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Guruji V, Zhou YQ, Tang M, Mirzaei Z, Ding Y, Elbatarny M, Latifi N, Simmons CA. Identification of congenital aortic valve malformations in juvenile natriuretic peptide receptor 2-deficient mice using high-frequency ultrasound. Am J Physiol Heart Circ Physiol 2024; 327:H56-H66. [PMID: 38758128 DOI: 10.1152/ajpheart.00769.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 04/19/2024] [Accepted: 05/05/2024] [Indexed: 05/18/2024]
Abstract
Mouse models of congenital aortic valve malformations are useful for studying disease pathobiology, but most models have incomplete penetrance [e.g., ∼2 to 77% prevalence of bicuspid aortic valves (BAVs) across multiple models]. For longitudinal studies of pathologies associated with BAVs and other congenital valve malformations, which manifest over months in mice, it is operationally inefficient, economically burdensome, and ethically challenging to enroll large numbers of mice in studies without first identifying those with valvular abnormalities. To address this need, we established and validated a novel in vivo high-frequency (30 MHz) ultrasound imaging protocol capable of detecting aortic valvular malformations in juvenile mice. Fifty natriuretic peptide receptor 2 heterozygous mice on a low-density lipoprotein receptor-deficient background (Npr2+/-;Ldlr-/-; 32 males and 18 females) were imaged at 4 and 8 wk of age. Fourteen percent of the Npr2+/-;Ldlr-/- mice exhibited features associated with aortic valve malformations, including 1) abnormal transaortic flow patterns on color Doppler (recirculation and regurgitation), 2) peak systolic flow velocities distal to the aortic valves reaching or surpassing ∼1,250 mm/s by pulsed-wave Doppler, and 3) putative fusion of cusps along commissures and abnormal movement elucidated by two-dimensional (2-D) imaging with ultrahigh temporal resolution. Valves with these features were confirmed by ex vivo gross anatomy and histological visualization to have thickened cusps, partial fusions, or Sievers type-0 bicuspid valves. This ultrasound imaging protocol will enable efficient, cost effective, and humane implementation of studies of congenital aortic valvular abnormalities and associated pathologies in a wide range of mouse models.NEW & NOTEWORTHY We developed a high-frequency ultrasound imaging protocol for diagnosing congenital aortic valve structural abnormalities in 4-wk-old mice. Our protocol defines specific criteria to distinguish mice with abnormal aortic valves from those with normal tricuspid valves using color Doppler, pulsed-wave Doppler, and two-dimensional (2-D) imaging with ultrahigh temporal resolution. This approach enables early identification of valvular abnormalities for efficient and ethical experimental design of longitudinal studies of congenital valve diseases and associated pathologies in mice.
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Affiliation(s)
- Vrushali Guruji
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Translational Biology and Engineering Program, Ted Rogers Center for Heart Research, Toronto, Ontario, Canada
| | - Yu-Qing Zhou
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Translational Biology and Engineering Program, Ted Rogers Center for Heart Research, Toronto, Ontario, Canada
| | - Mingyi Tang
- Translational Biology and Engineering Program, Ted Rogers Center for Heart Research, Toronto, Ontario, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Zahra Mirzaei
- Translational Biology and Engineering Program, Ted Rogers Center for Heart Research, Toronto, Ontario, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Yu Ding
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Translational Biology and Engineering Program, Ted Rogers Center for Heart Research, Toronto, Ontario, Canada
| | - Malak Elbatarny
- Translational Biology and Engineering Program, Ted Rogers Center for Heart Research, Toronto, Ontario, Canada
- Division of Cardiac Surgery, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Neda Latifi
- Translational Biology and Engineering Program, Ted Rogers Center for Heart Research, Toronto, Ontario, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Engineering, University of South Florida, Tampa, Florida, United States
| | - Craig A Simmons
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Translational Biology and Engineering Program, Ted Rogers Center for Heart Research, Toronto, Ontario, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
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Ho KL, Karwi Q, Wang F, Wagg C, Zhang L, Panidarapu S, Chen B, Pherwani S, Greenwell AA, Oudit G, Ussher JR, Lopaschuk GD. The ketogenic diet does not improve cardiac function and blunts glucose oxidation in ischemic heart failure. Cardiovasc Res 2024:cvae092. [PMID: 38691671 DOI: 10.1093/cvr/cvae092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/29/2024] [Accepted: 03/17/2024] [Indexed: 05/03/2024] Open
Abstract
AIMS Cardiac energy metabolism is perturbed in ischemic heart failure and is characterized by a shift from mitochondrial oxidative metabolism to glycolysis. Notably, the failing heart relies more on ketones for energy than a healthy heart, an adaptive mechanism that improves the energy-starved status of the failing heart. However, whether this can be implemented therapeutically remains unknown. Therefore, our aim was to determine if increasing ketone delivery to the heart via a ketogenic diet can improve the outcomes of heart failure. METHODS C57BL/6J male mice underwent either a sham surgery or permanent left anterior descending (LAD) coronary artery ligation surgery to induce heart failure. After 2 weeks, mice were then treated with either a control diet or a ketogenic diet for 3 weeks. Transthoracic echocardiography was then carried out to assess in vivo cardiac function and structure. Finally, isolated working hearts from these mice were perfused with appropriately 3H or 14C labelled glucose (5 mM), palmitate (0.8 mM), and ß-hydroxybutyrate (0.6 mM) to assess mitochondrial oxidative metabolism and glycolysis. RESULTS Mice with heart failure exhibited a 56% drop in ejection fraction which was not improved with a ketogenic diet feeding. Interestingly, mice fed a ketogenic diet had marked decreases in cardiac glucose oxidation rates. Despite increasing blood ketone levels, cardiac ketone oxidation rates did not increase, probably due to a decreased expression of key ketone oxidation enzymes. Furthermore, in mice on the ketogenic diet no increase in overall cardiac energy production was observed, and instead there was a shift to an increased reliance on fatty acid oxidation as a source of cardiac energy production. This resulted in a decrease in cardiac efficiency in heart failure mice fed a ketogenic diet. CONCLUSIONS We conclude that the ketogenic diet does not improve heart function in failing hearts, due to ketogenic diet-induced excessive fatty acid oxidation in the ischemic heart and a decrease in insulin-stimulated glucose oxidation.
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Affiliation(s)
- Kim L Ho
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Qutuba Karwi
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Faqi Wang
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Cory Wagg
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Liyan Zhang
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sai Panidarapu
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Brandon Chen
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Simran Pherwani
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Amanda A Greenwell
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Gavin Oudit
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - John R Ussher
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Gary D Lopaschuk
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Pherwani S, Connolly D, Sun Q, Karwi QG, Carr M, Ho KL, Wagg CS, Zhang L, Levasseur J, Silver H, Dyck JRB, Lopaschuk GD. Ketones provide an extra source of fuel for the failing heart without impairing glucose oxidation. Metabolism 2024; 154:155818. [PMID: 38369056 DOI: 10.1016/j.metabol.2024.155818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/20/2024]
Abstract
BACKGROUND Cardiac glucose oxidation is decreased in heart failure with reduced ejection fraction (HFrEF), contributing to a decrease in myocardial ATP production. In contrast, circulating ketones and cardiac ketone oxidation are increased in HFrEF. Since ketones compete with glucose as a fuel source, we aimed to determine whether increasing ketone concentration both chronically with the SGLT2 inhibitor, dapagliflozin, or acutely in the perfusate has detrimental effects on cardiac glucose oxidation in HFrEF, and what effect this has on cardiac ATP production. METHODS 8-week-old male C57BL6/N mice underwent sham or transverse aortic constriction (TAC) surgery to induce HFrEF over 3 weeks, after which TAC mice were randomized to treatment with either vehicle or the SGLT2 inhibitor, dapagliflozin (DAPA), for 4 weeks (raises blood ketones). Cardiac function was assessed by echocardiography. Cardiac energy metabolism was measured in isolated working hearts perfused with 5 mM glucose, 0.8 mM palmitate, and either 0.2 mM or 0.6 mM β-hydroxybutyrate (βOHB). RESULTS TAC hearts had significantly decreased %EF compared to sham hearts, with no effect of DAPA. Glucose oxidation was significantly decreased in TAC hearts compared to sham hearts and did not decrease further in TAC hearts treated with high βOHB or in TAC DAPA hearts, despite βOHB oxidation rates increasing in both TAC vehicle and TAC DAPA hearts at high βOHB concentrations. Rather, increasing βOHB supply to the heart selectively decreased fatty acid oxidation rates. DAPA significantly increased ATP production at both βOHB concentrations by increasing the contribution of glucose oxidation to ATP production. CONCLUSION Therefore, increasing ketone concentration increases energy supply and ATP production in HFrEF without further impairing glucose oxidation.
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Affiliation(s)
- Simran Pherwani
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - David Connolly
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Qiuyu Sun
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Qutuba G Karwi
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada; Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, Newfoundland and Labrador, St. John's A1B 3V6, Canada
| | - Michael Carr
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Kim L Ho
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Cory S Wagg
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Liyan Zhang
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Jody Levasseur
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Heidi Silver
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Jason R B Dyck
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Gary D Lopaschuk
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
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Sun Q, Güven B, Wagg CS, Almeida de Oliveira A, Silver H, Zhang L, Chen B, Wei K, Ketema EB, Karwi QG, Persad KL, Vu J, Wang F, Dyck JRB, Oudit GY, Lopaschuk GD. Mitochondrial fatty acid oxidation is the major source of cardiac adenosine triphosphate production in heart failure with preserved ejection fraction. Cardiovasc Res 2024; 120:360-371. [PMID: 38193548 DOI: 10.1093/cvr/cvae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 01/10/2024] Open
Abstract
AIMS Heart failure with preserved ejection fraction (HFpEF) is a prevalent disease worldwide. While it is well established that alterations of cardiac energy metabolism contribute to cardiovascular pathology, the precise source of fuel used by the heart in HFpEF remains unclear. The objective of this study was to define the energy metabolic profile of the heart in HFpEF. METHODS AND RESULTS Eight-week-old C57BL/6 male mice were subjected to a '2-Hit' HFpEF protocol [60% high-fat diet (HFD) + 0.5 g/L of Nω-nitro-L-arginine methyl ester]. Echocardiography and pressure-volume loop analysis were used for assessing cardiac function and cardiac haemodynamics, respectively. Isolated working hearts were perfused with radiolabelled energy substrates to directly measure rates of fatty acid oxidation, glucose oxidation, ketone oxidation, and glycolysis. HFpEF mice exhibited increased body weight, glucose intolerance, elevated blood pressure, diastolic dysfunction, and cardiac hypertrophy. In HFpEF hearts, insulin stimulation of glucose oxidation was significantly suppressed. This was paralleled by an increase in fatty acid oxidation rates, while cardiac ketone oxidation and glycolysis rates were comparable with healthy control hearts. The balance between glucose and fatty acid oxidation contributing to overall adenosine triphosphate (ATP) production was disrupted, where HFpEF hearts were more reliant on fatty acid as the major source of fuel for ATP production, compensating for the decrease of ATP originating from glucose oxidation. Additionally, phosphorylated pyruvate dehydrogenase levels decreased in both HFpEF mice and human patient's heart samples. CONCLUSION In HFpEF, fatty acid oxidation dominates as the major source of cardiac ATP production at the expense of insulin-stimulated glucose oxidation.
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Affiliation(s)
- Qiuyu Sun
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - Berna Güven
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Faculty of Pharmacy, Department of Pharmacology, Ankara University, Ankara, Turkey
| | - Cory S Wagg
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - Amanda Almeida de Oliveira
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Heidi Silver
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - Liyan Zhang
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - Brandon Chen
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
| | - Kaleigh Wei
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
| | - Ezra B Ketema
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - Qutuba G Karwi
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, Saint John's, Canada
| | - Kaya L Persad
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - Jennie Vu
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Faqi Wang
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Jason R B Dyck
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - Gavin Y Oudit
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Gary D Lopaschuk
- Cardiovascular Research Centre, University of Alberta, Edmonton, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
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Dewar MB, Ehsan F, Izumi A, Zhang H, Zhou YQ, Shah H, Langburt D, Suresh H, Wang T, Hacker A, Hinz B, Gillis J, Husain M, Heximer SP. Defining Transcriptomic Heterogeneity between Left and Right Ventricle-Derived Cardiac Fibroblasts. Cells 2024; 13:327. [PMID: 38391940 PMCID: PMC10887120 DOI: 10.3390/cells13040327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 01/27/2024] [Accepted: 02/04/2024] [Indexed: 02/24/2024] Open
Abstract
Cardiac fibrosis is a key aspect of heart failure, leading to reduced ventricular compliance and impaired electrical conduction in the myocardium. Various pathophysiologic conditions can lead to fibrosis in the left ventricle (LV) and/or right ventricle (RV). Despite growing evidence to support the transcriptomic heterogeneity of cardiac fibroblasts (CFs) in healthy and diseased states, there have been no direct comparisons of CFs in the LV and RV. Given the distinct natures of the ventricles, we hypothesized that LV- and RV-derived CFs would display baseline transcriptomic differences that influence their proliferation and differentiation following injury. Bulk RNA sequencing of CFs isolated from healthy murine left and right ventricles indicated that LV-derived CFs may be further along the myofibroblast transdifferentiation trajectory than cells isolated from the RV. Single-cell RNA-sequencing analysis of the two populations confirmed that Postn+ CFs were more enriched in the LV, whereas Igfbp3+ CFs were enriched in the RV at baseline. Notably, following pressure overload injury, the LV developed a larger subpopulation of pro-fibrotic Thbs4+/Cthrc1+ injury-induced CFs, while the RV showed a unique expansion of two less-well-characterized CF subpopulations (Igfbp3+ and Inmt+). These findings demonstrate that LV- and RV-derived CFs display baseline subpopulation differences that may dictate their diverging responses to pressure overload injury. Further study of these subpopulations will elucidate their role in the development of fibrosis and inform on whether LV and RV fibrosis require distinct treatments.
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Affiliation(s)
- Michael Bradley Dewar
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Fahad Ehsan
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Aliya Izumi
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Hangjun Zhang
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Yu-Qing Zhou
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
- Institute of Biomaterial & Biomedical Engineering, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Haisam Shah
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Dylan Langburt
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Hamsini Suresh
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Tao Wang
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Ted Rogers Centre for Heart Research, Toronto, ON M5G 1M1, Canada
| | - Alison Hacker
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Boris Hinz
- Keenan Research Institute for Biomedical Science of the St. Michael’s Hospital, Toronto, ON M5B 1W8, Canada
- Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Jesse Gillis
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Mansoor Husain
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Ted Rogers Centre for Heart Research, Toronto, ON M5G 1M1, Canada
| | - Scott Patrick Heximer
- Department of Physiology, University of Toronto, Toronto, ON M5G 1M1, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
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Sun Q, Wagg CS, Güven B, Wei K, de Oliveira AA, Silver H, Zhang L, Vergara A, Chen B, Wong N, Wang F, Dyck JRB, Oudit GY, Lopaschuk GD. Stimulating cardiac glucose oxidation lessens the severity of heart failure in aged female mice. Basic Res Cardiol 2024; 119:133-150. [PMID: 38148348 DOI: 10.1007/s00395-023-01020-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 12/28/2023]
Abstract
Heart failure is a prevalent disease worldwide. While it is well accepted that heart failure involves changes in myocardial energetics, what alterations that occur in fatty acid oxidation and glucose oxidation in the failing heart remains controversial. The goal of the study are to define the energy metabolic profile in heart failure induced by obesity and hypertension in aged female mice, and to attempt to lessen the severity of heart failure by stimulating myocardial glucose oxidation. 13-Month-old C57BL/6 female mice were subjected to 10 weeks of a 60% high-fat diet (HFD) with 0.5 g/L of Nω-nitro-L-arginine methyl ester (L-NAME) administered via drinking water to induce obesity and hypertension. Isolated working hearts were perfused with radiolabeled energy substrates to directly measure rates of myocardial glucose oxidation and fatty acid oxidation. Additionally, a series of mice subjected to the obesity and hypertension protocol were treated with a pyruvate dehydrogenase kinase inhibitor (PDKi) to stimulate cardiac glucose oxidation. Aged female mice subjected to the obesity and hypertension protocol had increased body weight, glucose intolerance, elevated blood pressure, cardiac hypertrophy, systolic dysfunction, and decreased survival. While fatty acid oxidation rates were not altered in the failing hearts, insulin-stimulated glucose oxidation rates were markedly impaired. PDKi treatment increased cardiac glucose oxidation in heart failure mice, which was accompanied with improved systolic function and decreased cardiac hypertrophy. The primary energy metabolic change in heart failure induced by obesity and hypertension in aged female mice is a dramatic decrease in glucose oxidation. Stimulating glucose oxidation can lessen the severity of heart failure and exert overall functional benefits.
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Affiliation(s)
- Qiuyu Sun
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Cory S Wagg
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Berna Güven
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Kaleigh Wei
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Amanda A de Oliveira
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
| | - Heidi Silver
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Liyan Zhang
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Ander Vergara
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
| | - Brandon Chen
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Nathan Wong
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Faqi Wang
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
| | - Jason R B Dyck
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada
| | - Gavin Y Oudit
- Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
| | - Gary D Lopaschuk
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada.
- Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada.
- Department of Pediatrics, University of Alberta, Edmonton, AB, T6G 2S2, Canada.
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7
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Rutledge C, Enriquez A, Redding K, Lopez M, Mullett S, Gelhaus SL, Jurczak M, Goetzman E, Kaufman BA. Liraglutide Protects Against Diastolic Dysfunction and Improves Ventricular Protein Translation. Cardiovasc Drugs Ther 2023:10.1007/s10557-023-07482-9. [PMID: 37382868 PMCID: PMC10788853 DOI: 10.1007/s10557-023-07482-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 06/30/2023]
Abstract
PURPOSE Diastolic dysfunction is an increasingly common cardiac pathology linked to heart failure with preserved ejection fraction. Previous studies have implicated glucagon-like peptide 1 (GLP-1) receptor agonists as potential therapies for improving diastolic dysfunction. In this study, we investigate the physiologic and metabolic changes in a mouse model of angiotensin II (AngII)-mediated diastolic dysfunction with and without the GLP-1 receptor agonist liraglutide (Lira). METHODS Mice were divided into sham, AngII, or AngII+Lira therapy for 4 weeks. Mice were monitored for cardiac function, weight change, and blood pressure at baseline and after 4 weeks of treatment. After 4 weeks of treatment, tissue was collected for histology, protein analysis, targeted metabolomics, and protein synthesis assays. RESULTS AngII treatment causes diastolic dysfunction when compared to sham mice. Lira partially prevents this dysfunction. The improvement in function in Lira mice is associated with dramatic changes in amino acid accumulation in the heart. Lira mice also have improved markers of protein translation by Western blot and increased protein synthesis by puromycin assay, suggesting that increased protein turnover protects against fibrotic remodeling and diastolic dysfunction seen in the AngII cohort. Lira mice also lost lean muscle mass compared to the AngII cohort, raising concerns about peripheral muscle scavenging as a source of the increased amino acids in the heart. CONCLUSIONS Lira therapy protects against AngII-mediated diastolic dysfunction, at least in part by promoting amino acid uptake and protein turnover in the heart. Liraglutide therapy is associated with loss of mean muscle mass, and long-term studies are warranted to investigate sarcopenia and frailty with liraglutide therapy in the setting of diastolic disease.
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Affiliation(s)
- Cody Rutledge
- Department of Medicine, Pittsburgh VA Medical Center, Pittsburgh, PA, USA
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Angela Enriquez
- Department of Medicine, Pittsburgh VA Medical Center, Pittsburgh, PA, USA
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kevin Redding
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mabel Lopez
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Steven Mullett
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stacy L Gelhaus
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael Jurczak
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eric Goetzman
- Rangos Research Center, Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA
| | - Brett A Kaufman
- Division of Cardiology, Vascular Medicine Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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8
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Zhou YQ, Bonafiglia QA, Zhang H, Heximer SP, Bendeck MP. Comprehensive ultrasound imaging of right ventricular remodeling under surgically induced pressure overload in mice. Am J Physiol Heart Circ Physiol 2023; 324:H391-H410. [PMID: 36607797 DOI: 10.1152/ajpheart.00590.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
This study reports a new methodology for right heart imaging by ultrasound in mice under right ventricular (RV) pressure overload. Pulmonary artery constriction (PAC) or sham surgeries were performed on C57BL/6 male mice at 8 wk of age. Ultrasound imaging was conducted at 2, 4, and 8 wk postsurgery using both classical and advanced ultrasound imaging modalities including electrocardiogram (ECG)-based kilohertz visualization, anatomical M-mode, and strain imaging. Based on pulsed Doppler, the PAC group demonstrated dramatically enhanced pressure gradient in the main pulmonary artery (MPA) as compared with the sham group. By the application of advanced imaging modalities in novel short-axis views of the ventricles, the PAC group demonstrated increased thickness of RV free wall, enlarged RV chamber, and reduced RV fractional shortening compared with the sham group. The PAC group also showed prolonged RV contraction, asynchronous interplay between RV and left ventricle (LV), and passive leftward motion of the interventricular septum (IVS) at early diastole. Consequently, the PAC group exhibited prolongation of LV isovolumic relaxation time, without change in LV wall thickness or systolic function. Significant correlations were found between the maximal pressure gradient in MPA measured by Doppler and the RV systolic pressure by catheterization, as well as the morphological and functional parameters of RV by ultrasound.NEW & NOTEWORTHY The established protocol overcomes the challenges in right heart imaging in mice, thoroughly elucidating the changes of RV, the dynamics of IVS, and the impact on LV and provides new insights into the pathophysiological mechanism of RV remodeling.
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Affiliation(s)
- Yu-Qing Zhou
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada.,Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Quinn A Bonafiglia
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Hangjun Zhang
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Scott P Heximer
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Michelle P Bendeck
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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9
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Teng ACT, Gu L, Di Paola M, Lakin R, Williams ZJ, Au A, Chen W, Callaghan NI, Zadeh FH, Zhou YQ, Fatah M, Chatterjee D, Jourdan LJ, Liu J, Simmons CA, Kislinger T, Yip CM, Backx PH, Gourdie RG, Hamilton RM, Gramolini AO. Tmem65 is critical for the structure and function of the intercalated discs in mouse hearts. Nat Commun 2022; 13:6166. [PMID: 36257954 PMCID: PMC9579145 DOI: 10.1038/s41467-022-33303-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/07/2022] [Indexed: 12/24/2022] Open
Abstract
The intercalated disc (ICD) is a unique membrane structure that is indispensable to normal heart function, yet its structural organization is not completely understood. Previously, we showed that the ICD-bound transmembrane protein 65 (Tmem65) was required for connexin43 (Cx43) localization and function in cultured mouse neonatal cardiomyocytes. Here, we investigate the functional and cellular effects of Tmem65 reductions on the myocardium in a mouse model by injecting CD1 mouse pups (3-7 days after birth) with recombinant adeno-associated virus 9 (rAAV9) harboring Tmem65 shRNA, which reduces Tmem65 expression by 90% in mouse ventricles compared to scrambled shRNA injection. Tmem65 knockdown (KD) results in increased mortality which is accompanied by eccentric hypertrophic cardiomyopathy within 3 weeks of injection and progression to dilated cardiomyopathy with severe cardiac fibrosis by 7 weeks post-injection. Tmem65 KD hearts display depressed hemodynamics as measured echocardiographically as well as slowed conduction in optical recording accompanied by prolonged PR intervals and QRS duration in electrocardiograms. Immunoprecipitation and super-resolution microscopy demonstrate a physical interaction between Tmem65 and sodium channel β subunit (β1) in mouse hearts and this interaction appears to be required for both the establishment of perinexal nanodomain structure and the localization of both voltage-gated sodium channel 1.5 (NaV1.5) and Cx43 to ICDs. Despite the loss of NaV1.5 at ICDs, whole-cell patch clamp electrophysiology did not reveal reductions in Na+ currents but did show reduced Ca2+ and K+ currents in Tmem65 KD cardiomyocytes in comparison to control cells. We conclude that disrupting Tmem65 function results in impaired ICD structure, abnormal cardiac electrophysiology, and ultimately cardiomyopathy.
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Affiliation(s)
- Allen C T Teng
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada.
| | - Liyang Gu
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
| | - Michelle Di Paola
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
| | - Robert Lakin
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Zachary J Williams
- The Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute at Virginia Tech. Carilion, Roanoke, VA, 24016, USA
- Translational Biology Medicine and Health Graduate Program, Virginia Tech, Roanoke, VA, 24016, USA
| | - Aaron Au
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Wenliang Chen
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Neal I Callaghan
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
| | - Farigol Hakem Zadeh
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
| | - Yu-Qing Zhou
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
| | - Meena Fatah
- The Labatt Family Heart Centre (Dept. of Pediatrics) and Translational Medicine, The Hospital for Sick Children & Research Institute, University of Toronto, Toronto, ON., M5G 1X8, Canada
| | - Diptendu Chatterjee
- The Labatt Family Heart Centre (Dept. of Pediatrics) and Translational Medicine, The Hospital for Sick Children & Research Institute, University of Toronto, Toronto, ON., M5G 1X8, Canada
| | - L Jane Jourdan
- The Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute at Virginia Tech. Carilion, Roanoke, VA, 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24060, USA
| | - Jack Liu
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Craig A Simmons
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
| | - Thomas Kislinger
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 1L7, Canada
| | - Christopher M Yip
- Institute of Biomedical Engineering, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, M5S 3G9, Canada
- Donnelly Centre, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Peter H Backx
- Department of Biology, York University, Toronto, ON, M3J 1P3, Canada
| | - Robert G Gourdie
- The Center for Heart and Reparative Medicine, Fralin Biomedical Research Institute at Virginia Tech. Carilion, Roanoke, VA, 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24060, USA
| | - Robert M Hamilton
- The Labatt Family Heart Centre (Dept. of Pediatrics) and Translational Medicine, The Hospital for Sick Children & Research Institute, University of Toronto, Toronto, ON., M5G 1X8, Canada
| | - Anthony O Gramolini
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, M5G 1M1, Canada.
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10
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Trittmann JK, Almazroue H, Nelin LD, Shaffer TA, Celestine CR, Green HW, Malbrue RA. PATET ratio by Doppler echocardiography: noninvasive detection of pediatric pulmonary arterial hypertension. Pediatr Res 2022; 92:631-636. [PMID: 34795389 PMCID: PMC9114166 DOI: 10.1038/s41390-021-01840-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 10/09/2021] [Accepted: 10/28/2021] [Indexed: 11/12/2022]
Abstract
Pulmonary artery acceleration time (PAT) and PAT: ejection time (PATET) ratio are echocardiographic measurements of pulmonary arterial hypertension (PAH). These noninvasive quantitative measurements are ideal to follow longitudinally through the clinical course of PAH, especially as it relates to the need for and/or response to treatment. This review article focuses on the current literature of PATET measurement for infants and children as it relates to the shortening of the PATET ratio in PAH. At the same time, further development of PATET as an outcome measure for PAH in preclinical models, particularly mice, such that the field can move forward to human clinical studies that are both safe and effective. Here, we present what is known about PATET in infants and children and discuss what is known in preclinical models with particular emphasis on neonatal mouse models. In both animal models and human disease, PATET allows for longitudinal measurements in the same individual, leading to more precise determinations of disease/model progression and/or response to therapy. IMPACT: PATET ratio is a quantitative measurement by a noninvasive technique, Doppler echocardiography, providing clinicians a more precise/accurate, safe, and longitudinal assessment of pediatric PAH. We present a brief history/state of the art of PATET ratio to predict PAH in adults, children, infants, and fetuses, as well as in small animal models of PAH. In a preliminary study, PATET shortened by 18% during acute hypoxic exposure compared to pre-hypoxia. Studies are needed to establish PATET, especially in mouse models of disease, such as bronchopulmonary, as a routine measure of PAH.
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Affiliation(s)
- Jennifer K. Trittmann
- Center for Perinatal Research, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH,Department of Pediatrics, The Ohio State University, College of Medicine, Columbus, OH,Jennifer K. Trittmann, MD, MPH, Center for Perinatal Research, Abigail Wexner Research Institute at, Nationwide Children’s Hospital and, The Ohio State University, College of Medicine, Columbus, OH, USA,
| | - Hanadi Almazroue
- Center for Perinatal Research, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH
| | - Leif D. Nelin
- Center for Perinatal Research, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH,Department of Pediatrics, The Ohio State University, College of Medicine, Columbus, OH
| | - Terri A. Shaffer
- Animal Resources Core, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH
| | - Charanda R. Celestine
- Louisiana State University, School of Veterinary Medicine, Department of Veterinary Clinical Sciences, Baton Rouge, LA, USA
| | - Henry W. Green
- Louisiana State University, School of Veterinary Medicine, Department of Veterinary Clinical Sciences, Baton Rouge, LA, USA
| | - Raphael A. Malbrue
- Animal Resources Core, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH,The Ohio State University, College of Veterinary Medicine, Columbus, OH
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11
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Assimopoulos S, Hammill C, Fernandes DJ, Spencer Noakes TL, Zhou YQ, Nutter LMJ, Ellegood J, Anagnostou E, Sled JG, Lerch JP. Genetic mouse models of autism spectrum disorder present subtle heterogenous cardiac abnormalities. Autism Res 2022; 15:1189-1208. [PMID: 35445787 PMCID: PMC9325472 DOI: 10.1002/aur.2728] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/16/2022] [Accepted: 03/28/2022] [Indexed: 12/13/2022]
Abstract
Autism spectrum disorder (ASD) and congenital heart disease (CHD) are linked on a functional and genetic level. Most work has investigated CHD‐related neurodevelopmental abnormalities. Cardiac abnormalities in ASD have been less studied. We investigated the prevalence of cardiac comorbidities relative to ASD genetic contributors. Using high frequency ultrasound imaging, we screened 9 ASD‐related genetic mouse models (Arid1b(+/−), Chd8(+/−), 16p11.2 (deletion), Sgsh(+/−), Sgsh(−/−), Shank3 Δexon 4–9(+/−), Shank3 Δexon 4–9(−/−), Fmr1(−/−), Vps13b(+/−)), and pooled wild‐type littermates (WTs). We measured heart rate (HR), aorta diameter (AoD), thickness and thickening of the left‐ventricular (LV) anterior and posterior walls, LV chamber diameter, fractional shortening, stroke volume and cardiac output, mitral inflow Peak E and A velocity ratio, ascending aorta velocity time integral (VTI). Mutant groups presented small‐scale alterations in cardiac structure and function compared to WTs (LV anterior wall thickness and thickening, chamber diameter and fractional shortening, HR). A greater number of significant differences was observed among mutant groups than between mutant groups and WTs. Mutant groups differed primarily in structural measures (LV chamber diameter and anterior wall thickness, HR, AoD). The mutant groups with most differences to WTs were 16p11.2 (deletion), Fmr1(−/−), Arid1b(+/−). The mutant groups with most differences from other mutant groups were 16p11.2 (deletion), Sgsh(+/−), Fmr1(−/−). Our results recapitulate the associated clinical findings. The characteristic ASD heterogeneity was recapitulated in the cardiac phenotype. The type of abnormal measures (morphological, functional) can highlight common underlying mechanisms. Clinically, knowledge of cardiac abnormalities in ASD can be essential as even non‐lethal abnormalities impact normal development.
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Affiliation(s)
- Stephania Assimopoulos
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada.,Sickkids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Christopher Hammill
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada.,Sickkids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Darren J Fernandes
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada.,Sickkids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Tara Leigh Spencer Noakes
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada.,Sickkids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Yu-Qing Zhou
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Lauryl M J Nutter
- Sickkids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Centre for Phenogenomics, Toronto, Ontario, Canada
| | - Jacob Ellegood
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada.,Sickkids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Evdokia Anagnostou
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, Toronto, Ontario, Canada
| | - John G Sled
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada.,Sickkids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Jason P Lerch
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada.,Sickkids Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Wellcome Centre for Integrative Neuroimaging, The University of Oxford, Oxford, UK
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12
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Loai S, Zhou YQ, Vollett KDW, Cheng HLM. Skeletal Muscle Microvascular Dysfunction Manifests Early in Diabetic Cardiomyopathy. Front Cardiovasc Med 2021; 8:715400. [PMID: 34355034 PMCID: PMC8329089 DOI: 10.3389/fcvm.2021.715400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 06/28/2021] [Indexed: 12/03/2022] Open
Abstract
Aim: To perform a deep cardiac phenotyping of type II diabetes in a rat model, with the goal of gaining new insight into the temporality of microvascular dysfunction, cardiac dysfunction, and exercise intolerance at different stages of diabetes. Methods and Results: Diabetes was reproduced using a non-obese, diet-based, low-dose streptozotocin model in male rats (29 diabetic, 11 control). Time-course monitoring over 10 months was performed using echocardiography, treadmill exercise, photoacoustic perfusion imaging in myocardial and leg skeletal muscle, flow-mediated dilation, blood panel, and histology. Diabetic rats maintained a normal weight throughout. At early times (4 months), a non-significant reduction (30%) emerged in skeletal muscle perfusion and in exercise tolerance. At the same time, diabetic rats had a normal, slightly lower ejection fraction (63 vs. 71% control, p < 0.01), grade 1 diastolic dysfunction (E/A = 1.1 vs. 1.5, isovolumetric relaxation time = 34 vs. 27 ms; p < 0.01), mild systolic dysfunction (ejection time = 69 vs. 57 ms, isovolumetric contraction time = 21 vs. 17 ms; p < 0.01), and slightly enlarged left ventricle (8.3 vs. 7.6 mm diastole; p < 0.01). Diastolic dysfunction entered grade 3 at Month 8 (E/A = 1.7 vs. 1.3, p < 0.05). Exercise tolerance remained low in diabetic rats, with running distance declining by 60%; in contrast, control rats ran 60% farther by Month 5 (p < 0.05) and always remained above baseline. Leg muscle perfusion remained low in diabetic rats, becoming significantly lower than control by Month 10 (33% SO2 vs. 57% SO2, p < 0.01). Myocardial perfusion remained normal throughout. Femoral arterial reactivity was normal, but baseline velocity was 25% lower than control (p < 0.05). High blood pressure appeared late in diabetes (8 months). Histology confirmed absence of interstitial fibrosis, cardiomyocyte hypertrophy, or microvascular rarefaction in the diabetic heart. Rarefaction was also absent in leg skeletal muscle. Conclusion: Reduced skeletal muscle perfusion from microvascular dysfunction emerged early in diabetic rats, but myocardial perfusion remained normal throughout the study. At the same time, diabetic rats exhibited exercise intolerance and early cardiac dysfunction, in which changes related to heart failure with preserved ejection fraction (HFpEF) were seen. Importantly, skeletal muscle microvascular constriction advanced significantly before the late appearance of hypertension. HFpEF phenotypes such as cardiac hypertrophy, fibrosis, and rarefaction, which are typically associated with hypertension, were absent over the 10 month time-course of diabetes-related heart failure.
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Affiliation(s)
- Sadi Loai
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, Canada
| | - Yu-Qing Zhou
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, Canada
| | - Kyle D W Vollett
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, Canada
| | - Hai-Ling Margaret Cheng
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, Canada.,The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
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13
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Shah H, Hacker A, Langburt D, Dewar M, McFadden MJ, Zhang H, Kuzmanov U, Zhou YQ, Hussain B, Ehsan F, Hinz B, Gramolini AO, Heximer SP. Myocardial Infarction Induces Cardiac Fibroblast Transformation within Injured and Noninjured Regions of the Mouse Heart. J Proteome Res 2021; 20:2867-2881. [PMID: 33789425 DOI: 10.1021/acs.jproteome.1c00098] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Heart failure (HF) is associated with pathological remodeling of the myocardium, including the initiation of fibrosis and scar formation by activated cardiac fibroblasts (CFs). Although early CF-dependent scar formation helps prevent cardiac rupture by maintaining the heart's structural integrity, ongoing deposition of the extracellular matrix in the remote and infarct regions can reduce tissue compliance, impair cardiac function, and accelerate progression to HF. In our study, we conducted mass spectrometry (MS) analysis to identify differentially altered proteins and signaling pathways between CFs isolated from 7 day sham and infarcted murine hearts. Surprisingly, CFs from both the remote and infarct regions of injured hearts had a wide number of similarly altered proteins and signaling pathways that were consistent with fibrosis and activation into pathological myofibroblasts. Specifically, proteins enriched in CFs isolated from MI hearts were involved in pathways pertaining to cell-cell and cell-matrix adhesion, chaperone-mediated protein folding, and collagen fibril organization. These results, together with principal component analyses, provided evidence of global CF activation postinjury. Interestingly, however, direct comparisons between CFs from the remote and infarct regions of injured hearts identified 15 differentially expressed proteins between MI remote and MI infarct CFs. Eleven of these proteins (Gpc1, Cthrc1, Vmac, Nexn, Znf185, Sprr1a, Specc1, Emb, Limd2, Pawr, and Mcam) were higher in MI infarct CFs, whereas four proteins (Gstt1, Gstm1, Tceal3, and Inmt) were higher in MI remote CFs. Collectively, our study shows that MI injury induced global changes to the CF proteome, with the magnitude of change reflecting their relative proximity to the site of injury.
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Affiliation(s)
- Haisam Shah
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1.,Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Alison Hacker
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
| | - Dylan Langburt
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1.,Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Michael Dewar
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1.,Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Meghan J McFadden
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
| | - Hangjun Zhang
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
| | - Uros Kuzmanov
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1.,Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Yu-Qing Zhou
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
| | - Bilal Hussain
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
| | - Fahad Ehsan
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1.,Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Boris Hinz
- Laboratory of Tissue Repair and Regeneration, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6
| | - Anthony O Gramolini
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1.,Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Scott P Heximer
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1.,Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
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14
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Ho KL, Zhang L, Wagg C, Al Batran R, Gopal K, Levasseur J, Leone T, Dyck JRB, Ussher JR, Muoio DM, Kelly DP, Lopaschuk GD. Increased ketone body oxidation provides additional energy for the failing heart without improving cardiac efficiency. Cardiovasc Res 2020; 115:1606-1616. [PMID: 30778524 DOI: 10.1093/cvr/cvz045] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/18/2018] [Accepted: 02/13/2019] [Indexed: 02/06/2023] Open
Abstract
AIMS The failing heart is energy-starved and inefficient due to perturbations in energy metabolism. Although ketone oxidation has been shown recently to increase in the failing heart, it remains unknown whether this improves cardiac energy production or efficiency. We therefore assessed cardiac metabolism in failing hearts and determined whether increasing ketone oxidation improves cardiac energy production and efficiency. METHODS AND RESULTS C57BL/6J mice underwent sham or transverse aortic constriction (TAC) surgery to induce pressure overload hypertrophy over 4-weeks. Isolated working hearts from these mice were perfused with radiolabelled β-hydroxybutyrate (βOHB), glucose, or palmitate to assess cardiac metabolism. Ejection fraction decreased by 45% in TAC mice. Failing hearts had decreased glucose oxidation while palmitate oxidation remained unchanged, resulting in a 35% decrease in energy production. Increasing βOHB levels from 0.2 to 0.6 mM increased ketone oxidation rates from 251 ± 24 to 834 ± 116 nmol·g dry wt-1 · min-1 in TAC hearts, rates which were significantly increased compared to sham hearts and occurred without decreasing glycolysis, glucose, or palmitate oxidation rates. Therefore, the contribution of ketones to energy production in TAC hearts increased to 18% and total energy production increased by 23%. Interestingly, glucose oxidation, in parallel with total ATP production, was also significantly upregulated in hearts upon increasing βOHB levels. However, while overall energy production increased, cardiac efficiency was not improved. CONCLUSIONS Increasing ketone oxidation rates in failing hearts increases overall energy production without compromising glucose or fatty acid metabolism, albeit without increasing cardiac efficiency.
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Affiliation(s)
- Kim L Ho
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada
| | - Liyan Zhang
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada
| | - Cory Wagg
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada
| | - Rami Al Batran
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada.,Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Keshav Gopal
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada.,Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Jody Levasseur
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada
| | - Teresa Leone
- Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA, USA
| | - Jason R B Dyck
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada
| | - John R Ussher
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada.,Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Deborah M Muoio
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, 300 N Duke St, Durham, NC, USA
| | - Daniel P Kelly
- Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA, USA
| | - Gary D Lopaschuk
- Cardiovascular Research Centre, Faculty of Medicine and Dentistry, 423 Heritage Medical Research Centre, University of Alberta, Edmonton, AB, Canada
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15
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Spencer Noakes TL, Przybycien TS, Forwell A, Nicholls C, Zhou YQ, Butcher DT, Weksberg R, Guger SL, Spiegler BJ, Schachar RJ, Hitzler J, Ito S, van der Plas E, Nieman BJ. Brain Development and Heart Function after Systemic Single-Agent Chemotherapy in a Mouse Model of Childhood Leukemia Treatment. Clin Cancer Res 2018; 24:6040-6052. [PMID: 30054283 DOI: 10.1158/1078-0432.ccr-18-0551] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/19/2018] [Accepted: 07/24/2018] [Indexed: 11/16/2022]
Abstract
PURPOSE Chemotherapy for childhood acute lymphoblastic leukemia (ALL) can cause late-appearing side effects in survivors that affect multiple organs, including the heart and brain. However, the complex ALL treatment regimen makes it difficult to isolate the causes of these side effects and impossible to separate the contributions of individual chemotherapy agents by clinical observation. Using a mouse model, we therefore assessed each of eight representative, systemically-administered ALL chemotherapy agents for their impact on postnatal brain development and heart function. EXPERIMENTAL DESIGN Mice were treated systemically with a single chemotherapy agent at an infant equivalent age, then allowed to age to early adulthood (9 weeks). Cardiac structure and function were assessed using in vivo high-frequency ultrasound, and brain anatomy was assessed using high-resolution volumetric ex vivo MRI. In addition, longitudinal in vivo MRI was used to determine the time course of developmental change after vincristine treatment. RESULTS Vincristine, doxorubicin, and methotrexate were observed to produce the greatest deficiencies in brain development as determined by volumes measured on MRI, whereas doxorubicin, methotrexate, and l-asparaginase altered heart structure or function. Longitudinal studies of vincristine revealed widespread volume loss immediately following treatment and impaired growth over time in several brain regions. CONCLUSIONS Multiple ALL chemotherapy agents can affect postnatal brain development or heart function. This study provides a ranking of agents based on potential toxicity, and thus highlights a subset likely to cause side effects in early adulthood for further study.
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Affiliation(s)
- T Leigh Spencer Noakes
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.
- Translational Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Thomas S Przybycien
- Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Amanda Forwell
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- The University of Waterloo, Waterloo, Ontario, Canada
| | - Connor Nicholls
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- The University of Waterloo, Waterloo, Ontario, Canada
| | - Yu-Qing Zhou
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, The University of Toronto, Ontario, Canada
| | - Darci T Butcher
- Genetics & Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Rosanna Weksberg
- Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Genetics & Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Clinical and Metabolic Genetics, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Molecular Genetics, The University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Sciences, The University of Toronto, Toronto, Ontario, Canada
| | - Sharon L Guger
- Department of Molecular Genetics, The University of Toronto, Toronto, Ontario, Canada
| | - Brenda J Spiegler
- Department of Psychology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, Faculty of Medicine, The University of Toronto, Toronto, Ontario, Canada
| | - Russell J Schachar
- Department of Psychiatry, The Hospital for Sick Children, Toronto, Ontario, Canada
- Psychiatry Research, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Johann Hitzler
- Translational Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Pediatrics, Faculty of Medicine, The University of Toronto, Toronto, Ontario, Canada
- Development and Stem Cell Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Shinya Ito
- Translational Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Clinical Pharmacology and Toxicology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Pharmacology and Toxicology, Faculty of Medicine, The University of Toronto, Toronto, Ontario, Canada
| | - Ellen van der Plas
- Department of Psychiatry, The University of Iowa Hospital and Clinics, Iowa City, Iowa
| | - Brian J Nieman
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Translational Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
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16
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Mistry N, Mazer CD, Sled JG, Lazarus AH, Cahill LS, Solish M, Zhou YQ, Romanova N, Hare AGM, Doctor A, Fisher JA, Brunt KR, Simpson JA, Hare GMT. Red blood cell antibody-induced anemia causes differential degrees of tissue hypoxia in kidney and brain. Am J Physiol Regul Integr Comp Physiol 2018; 314:R611-R622. [PMID: 29351418 DOI: 10.1152/ajpregu.00182.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Moderate anemia is associated with increased mortality and morbidity, including acute kidney injury (AKI), in surgical patients. A red blood cell (RBC)-specific antibody model was utilized to determine whether moderate subacute anemia could result in tissue hypoxia as a potential mechanism of injury. Cardiovascular and hypoxic cellular responses were measured in transgenic mice capable of expressing hypoxia-inducible factor-1α (HIF-1α)/luciferase activity in vivo. Antibody-mediated anemia was associated with mild intravascular hemolysis (6 h) and splenic RBC sequestration ( day 4), resulting in a nadir hemoglobin concentration of 89 ± 13 g/l on day 4. At this time point, renal tissue oxygen tension (PtO2) was decreased in anemic mice relative to controls (13.1 ± 4.3 vs. 20.8 ± 3.7 mmHg, P < 0.001). Renal tissue hypoxia was associated with an increase in HIF/luciferase expression in vivo ( P = 0.04) and a 20-fold relative increase in renal erythropoietin mRNA transcription ( P < 0.001) but no increase in renal blood flow ( P = 0.67). By contrast, brain PtO2 was maintained in anemic mice relative to controls (22.7 ± 5.2 vs. 23.4 ± 9.8 mmHg, P = 0.59) in part because of an increase in internal carotid artery blood flow (80%, P < 0.001) and preserved cerebrovascular reactivity. Despite these adaptive changes, an increase in brain HIF-dependent mRNA levels was observed (erythropoietin: P < 0.001; heme oxygenase-1: P = 0.01), providing evidence for subtle cerebral tissue hypoxia in anemic mice. These data demonstrate that moderate subacute anemia causes significant renal tissue hypoxia, whereas adaptive cerebrovascular responses limit the degree of cerebral tissue hypoxia. Further studies are required to assess whether hypoxia is a mechanism for acute kidney injury associated with anemia.
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Affiliation(s)
- Nikhil Mistry
- Department of Anesthesia, St. Michael's Hospital, University of Toronto , Toronto, Ontario , Canada.,Department of Physiology, University of Toronto , Toronto, Ontario , Canada
| | - C David Mazer
- Department of Anesthesia, St. Michael's Hospital, University of Toronto , Toronto, Ontario , Canada.,Department of Physiology, University of Toronto , Toronto, Ontario , Canada.,Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael's Hospital , Toronto, Ontario , Canada
| | - John G Sled
- Mouse Imaging Centre, The Hospital for Sick Children , Toronto, Ontario , Canada.,Department of Medical Biophysics, University of Toronto , Toronto, Ontario , Canada
| | - Alan H Lazarus
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael's Hospital , Toronto, Ontario , Canada.,Canadian Blood Services Centre for Innovation , Ottawa, Ontario , Canada
| | - Lindsay S Cahill
- Mouse Imaging Centre, The Hospital for Sick Children , Toronto, Ontario , Canada
| | - Max Solish
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael's Hospital , Toronto, Ontario , Canada
| | - Yu-Qing Zhou
- Mouse Imaging Centre, The Hospital for Sick Children , Toronto, Ontario , Canada
| | - Nadya Romanova
- Department of Human Health and Nutritional Sciences and Cardiovascular Research Group, University of Guelph , Guelph, Ontario , Canada
| | - Alexander G M Hare
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael's Hospital , Toronto, Ontario , Canada
| | - Allan Doctor
- Department of Pediatrics, Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis , St. Louis, Missouri
| | - Joseph A Fisher
- Department of Physiology, University of Toronto , Toronto, Ontario , Canada.,Department of Anesthesia, Toronto General Hospital, University of Toronto , Toronto, Ontario , Canada
| | - Keith R Brunt
- Department of Pharmacology, Dalhousie University , Saint John, New Brunswick , Canada
| | - Jeremy A Simpson
- Department of Human Health and Nutritional Sciences and Cardiovascular Research Group, University of Guelph , Guelph, Ontario , Canada
| | - Gregory M T Hare
- Department of Anesthesia, St. Michael's Hospital, University of Toronto , Toronto, Ontario , Canada.,Department of Physiology, University of Toronto , Toronto, Ontario , Canada.,Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael's Hospital , Toronto, Ontario , Canada.,St. Michael's Hospital Center of Excellence in Patient Blood Management, University of Toronto, Toronto, Ontario, Canada
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17
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Sakata M, Ohigashi I, Takahama Y. Cellularity of Thymic Epithelial Cells in the Postnatal Mouse. THE JOURNAL OF IMMUNOLOGY 2018; 200:1382-1388. [PMID: 29298829 DOI: 10.4049/jimmunol.1701235] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 12/05/2017] [Indexed: 12/13/2022]
Abstract
The molecular and cellular biology of thymic epithelial cells (TECs) often relies on the analysis of TECs isolated in enzymatically digested single-cell suspensions derived from mouse thymus. Many independent studies have reported that the estimated cellularity of total TECs isolated from one adult mouse is on the order of up to 105 However, these numbers appear extremely small given that the cellularity of total thymocytes exceeds 108 and that TECs play multiple roles in thymocyte development and repertoire formation. In the present study, we aimed to measure the numbers of β5t-expressing cortical TECs and Aire-expressing medullary TECs in postnatal mouse thymus in situ without enzymatic digestion. The numbers of these TECs were manually counted in individual thymic sections and were three-dimensionally summed throughout the entire thymic lobes. The results show that the cellularity of total TECs in one 5-wk-old female mouse exceeds 106, containing ∼9 × 105 β5t+ cortical TECs and ∼1.1 × 106 Aire+ medullary TECs. These results suggest that the use of conventional enzymatic digestion methods for the isolation of TECs may have resulted in the underestimation of the cellularity, and possibly the biology, of TECs.
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Affiliation(s)
- Mie Sakata
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Izumi Ohigashi
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Yousuke Takahama
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
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18
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Li Z, Li Y, Zhang L, Zhang X, Sullivan R, Ai X, Szeto C, Cai A, Liu L, Xiao W, Li Q, Ge S, Chen X. Reduced Myocardial Reserve in Young X-Linked Muscular Dystrophy Mice Diagnosed by Two-Dimensional Strain Analysis Combined with Stress Echocardiography. J Am Soc Echocardiogr 2017; 30:815-827.e9. [PMID: 28511858 DOI: 10.1016/j.echo.2017.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Indexed: 01/16/2023]
Abstract
BACKGROUND Early, sensitive, and reproducible evaluation of left ventricular function is imperative for the diagnosis of cardiac dysfunction in patients with Duchene muscular dystrophy. The aim of this study was to test the hypothesis that combining two-dimensional strain analysis with catecholamine stress could be a sensitive method for detecting early cardiac dysfunction. METHODS Mdx (C57BL/10ScSn-Dmdmdx/J, a mouse model of DMD) and control (C57BL/10ScSn) mice were studied with conventional M-mode and high-frequency ultrasound-based two-dimensional speckle-tracking echocardiography using long- and short-axis images of the left ventricle at baseline and after intraperitoneal isoprenaline (ISO) administration (2 μg/g body weight). RESULTS Conventional M-mode analysis showed no differences in left ventricular fractional shortening, wall thickness, or internal diameter at diastole between mdx and control mice before the age of 6 months. ISO increased left ventricular ejection fraction and fractional shortening to the same extent in mdx and control mice at young ages (3, 4, and 5 months). No differences in basal peak systolic strain (PSS) but increased SDs of times to PSS between young mdx and control mice were found. After ISO, PSS and percentile changes of PSS were significantly diminished in mdx mice compared with control mice at young ages. ISO increased the normalized maximum difference of times to PSS in young mdx mice but not in young control mice, suggesting that ISO reduces cardiac contractile synchrony in young mdx mice. CONCLUSIONS This study suggests that catecholamine stress coupled with two-dimensional strain analysis is a feasible and sensitive approach for detecting early onset of cardiac dysfunction, which is instrumental for early diagnosis of cardiac dysfunction and early treatment.
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Affiliation(s)
- Zhenzhou Li
- Department of Ultrasound, The Second People's Hospital of Shenzhen, Shenzhen, China; Drexel University College of Medicine, Philadelphia, Pennsylvania; Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - Ying Li
- Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania; The General Hospital of The PLA Rocket Force, Beijing, China
| | - Li Zhang
- Drexel University College of Medicine, Philadelphia, Pennsylvania; Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania; Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoying Zhang
- Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - Rebecca Sullivan
- Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - Xiaojie Ai
- Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania; College of Biological Sciences, Shanghai Jiaotong University, Shanghai, China
| | - Christopher Szeto
- Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - Angela Cai
- Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - Longjian Liu
- Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Weidong Xiao
- Department of Microbiology and Immunology and Sol Sherry Thrombosis Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - Quanshui Li
- Department of Ultrasound, The Second People's Hospital of Shenzhen, Shenzhen, China
| | - Shuping Ge
- Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Xiongwen Chen
- Department of Physiology and Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania.
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19
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Huang J, Wu J, Wang S, You J, Ye Y, Ding Z, Yang F, Wang X, Guo J, Ma L, Yuan J, Shen Y, Yang X, Sun A, Jiang H, Bu L, Backx PH, Ge J, Zou Y. Ultrasound biomicroscopy validation of a murine model of cardiac hypertrophic preconditioning: comparison with a hemodynamic assessment. Am J Physiol Heart Circ Physiol 2017; 313:H138-H148. [PMID: 28455286 DOI: 10.1152/ajpheart.00004.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/23/2017] [Accepted: 04/06/2017] [Indexed: 01/09/2023]
Abstract
In mice, myocardial hypertrophic preconditioning (HP), which is produced by the removal of short-term transverse aortic constriction (TAC), was recently reported to render the heart resistant to hypertrophic responses induced by subsequent reconstriction (Re-TAC). However, there is no efficient noninvasive method for ensuring that the repeated aortic manipulations were successfully performed. We previously demonstrated that ultrasound biomicroscopy (UBM) is a noninvasive and effective approach for predicting TAC success. Here, we investigated the value of UBM for serial predictions of load conditions in establishing a murine HP model. C57BL/6J mice were subjected to a sham operation, TAC, or Re-TAC, and the peak flow velocity at the aortic banding site (PVb) was measured by UBM. Left ventricular end-systolic pressure (LVESP) was examined by micromanometric catheterization. The PVb was positively associated with LVESP (R2 = 0.8204, P < 0.001, for TAC at 3 days and R2 = 0.7746, P < 0.001, for Re-TAC at 4 wk). PVb and LVESP values were markedly elevated after aortic banding, became attenuated to the sham-operated level after debanding, and increased after aortic rebanding. The cardiac hypertrophic responses were examined by UBM, histology, RT-PCR, and Western blot analysis. Four weeks after the last operation, with PVb ≥ 3.5 m/s as an indicator of successful aortic constriction, Re-TAC mice showed less cardiac hypertrophy, fetal gene expression, and ERK1/2 activation than TAC mice. Therefore, we successfully established a UBM protocol for the serial assessment of aortic flow and the prediction of LVESP during repeated aortic manipulations in mice, which might be useful for noninvasive evaluations of the murine HP model.NEW & NOTEWORTHY We successfully developed an ultrasound biomicroscopy protocol for the serial assessment of aortic bandings and the relevant left ventricular pressure in a murine model of cardiac hypertrophic preconditioning. The protocol may be of great importance in the successful establishment of the hypertrophic preconditioning model for further mechanistic and pharmacological studies.
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Affiliation(s)
- Jiayuan Huang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Jian Wu
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Shijun Wang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Jieyun You
- Department of Cardiovascular Medicine, East Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Yong Ye
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Zhiwen Ding
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Fenghua Yang
- Guangdong Laboratory Animal Monitoring Institute, Guangzhou, People's Republic of China
| | - Xingxu Wang
- Department of Cardiovascular Medicine, East Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Junjie Guo
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China.,Department of Cardiology, The Affiliated Hospital of Qingdao University, Qingdao, People's Republic of China
| | - Leilei Ma
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Jie Yuan
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Yunli Shen
- Department of Cardiovascular Medicine, East Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Xiangdong Yang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Aijun Sun
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Hong Jiang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Liping Bu
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Peter H Backx
- Departments of Physiology and Medicine, University of Toronto, Toronto, Ontario; and.,Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Junbo Ge
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China
| | - Yunzeng Zou
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China;
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20
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Khandoker AH, Al Khoori T, Ito T, Sugibayashi R, Kimura Y. Assessment of autonomic neurodevelopment in the mouse fetuses by using fetal electrocardiography. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:2954-2957. [PMID: 28268932 DOI: 10.1109/embc.2016.7591349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fetal Electrocardiography (FECG) offers unique capabilities for assessment of beat-to-beat fetal heart rate (FHR) and fetal heart rate variability (FHRV), which are indirect markers of autonomic nervous system, its development. In this study the fetal ECG signals, FHR and FHRV are successfully recorded to assess the neurodevelopment in fetal mice in the second and third trimester from days 12.5 to 18.5 by using direct insertion of fetal ECG electrodes in the uterine. FHR increases from day 12.5 till 15.5 reaching a plateau and then shows a sudden increase on the day 18.5. Development of fetal increasing heart rate variability (FHRV) is clearly evident from the results. Short term FHRV (RMSSD) corresponding to parasympathetic nervous system activity and long term FHRV (SDNN) corresponding to sympathetic and parasympathetic nervous system activities increases till day 16.5 and then decreases from day 17.5. The increases in large fluctuations were noticed on days 17.5 and 18.5, which were thought to have caused by uterine contractions before delivery. The ability to assess FHR and FHRV in fetal mice makes a valuable tool for neurodevelopment research in perinatal medicine.
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21
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The role of GRIP1 and ephrin B3 in blood pressure control and vascular smooth muscle cell contractility. Sci Rep 2016; 6:38976. [PMID: 27941904 PMCID: PMC5150233 DOI: 10.1038/srep38976] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 11/16/2016] [Indexed: 12/25/2022] Open
Abstract
Several erythropoietin-producing hepatocellular receptor B family (EPHB) and their ligands, ephrinBs (EFNBs), are involved in blood pressure regulation in animal models. We selected 528 single nucleotide polymorphisms (SNPs) within the genes of EPHB6, EFNB2, EFNB3 and GRIP1 in the EPH/EFN signalling system to query the International Blood Pressure Consortium dataset. A SNP within the glutamate receptor interacting protein 1 (GRIP1) gene presented a p-value of 0.000389, approaching the critical p-value of 0.000302, for association with diastolic blood pressure of 60,396 individuals. According to echocardiography, we found that Efnb3 gene knockout mice showed enhanced constriction in the carotid arteries. In vitro studies revealed that in mouse vascular smooth muscle cells, siRNA knockdown of GRIP1, which is in the EFNB3 reverse signalling pathway, resulted in increased contractility of these cells. These data suggest that molecules in the EPHB/EFNB signalling pathways, specifically EFNB3 and GRIP1, are involved blood pressure regulation.
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22
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Abstract
In order to understand the consequences of the mutation on behavioral and biological phenotypes relevant to autism, mutations in many of the risk genes for autism spectrum disorder have been experimentally generated in mice. Here, we summarize behavioral outcomes and neuroanatomical abnormalities, with a focus on high-resolution magnetic resonance imaging of postmortem mouse brains. Results are described from multiple mouse models of autism spectrum disorder and comorbid syndromes, including the 15q11-13, 16p11.2, 22q11.2, Cntnap2, Engrailed2, Fragile X, Integrinβ3, MET, Neurexin1a, Neuroligin3, Reelin, Rett, Shank3, Slc6a4, tuberous sclerosis, and Williams syndrome models, and inbred strains with strong autism-relevant behavioral phenotypes, including BTBR and BALB. Concomitant behavioral and neuroanatomical abnormalities can strengthen the interpretation of results from a mouse model, and may elevate the usefulness of the model system for therapeutic discovery.
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Affiliation(s)
- Jacob Ellegood
- />Mouse Imaging Centre (MICe), Hospital for Sick Children, 25 Orde Street, Toronto, ON M5T 3H7 Canada
| | - Jacqueline N. Crawley
- />MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, 4625 2nd Avenue, Sacramento, CA 95817 USA
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Murine left atrium and left atrial appendage structure and function: echocardiographic and morphologic evaluation. PLoS One 2015; 10:e0125541. [PMID: 25928887 PMCID: PMC4415937 DOI: 10.1371/journal.pone.0125541] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 03/25/2015] [Indexed: 11/19/2022] Open
Abstract
Aim of this study was to provide an echocardiographic protocol for the description of the normal murine venous reservoir (atrium, appendage and pulmonary veins) and to investigate the possibility to use this approach to discriminate changes on left atrium (LA) and left atrial appendage (LAA) in a stress-induced model such us myocardial infarction. Global left ventricular function and the venous reservoir were assessed by a Vevo2100 in 20 female C57BL/6N. LA and LAA were also studied in 10 CD-1 and 10 FVB mice, whereas modifications investigated in 15 C57BL/6N subjected to coronary artery ligation. Left ventricle function was evaluated as well as pulsed Doppler mitral valve, pulmonary vein, and LAA velocities. From 2D view monoplane LA volumes were obtained and LAA long axis measured. Macroscopic inspection with casts and immunohistochemistry were performed. Results show that compared to humans, in C57BL/6N mice left atrium was disproportionately smaller (5.2±1.4 μL) than the left ventricle (53±8 μL) and connected through a duct by a large LAA and posteriorly to three pulmonary veins. The LA volume increased 2-fold during reservoir with two distinct phases, early and late divided by a short pause. LAA long axis (4.1±0.5 mm) was almost 2 times longer than the LA. LAA flow volume together with LA volume reservoir account for about 36% of stroke volume and the rest was provided by conduit flow. Linear regressions showed that stroke volume was strongly influenced by LAA flow, LA early filling volume and left ventricle base descent. Moreover, we also report the ability to assess LA and LAA in other mice strains and discriminate size increase following myocardial infarction. In conclusion, we performed a complete characterization of murine left venous reservoir establishing an optimized protocol that can be used in both investigative and pharmacological studies requiring rapid and serial determination of cardiac structure and function.
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Egemnazarov B, Schmidt A, Crnkovic S, Sydykov A, Nagy BM, Kovacs G, Weissmann N, Olschewski H, Olschewski A, Kwapiszewska G, Marsh LM. Pressure Overload Creates Right Ventricular Diastolic Dysfunction in a Mouse Model: Assessment by Echocardiography. J Am Soc Echocardiogr 2015; 28:828-43. [PMID: 25840639 DOI: 10.1016/j.echo.2015.02.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Indexed: 10/23/2022]
Abstract
BACKGROUND Noninvasive diagnostic tools for right ventricular (RV) dysfunction measurements are increasingly being used, although their association with the pathologic mechanisms of dysfunction is poorly understood. Although investigations have focused mainly on RV systolic function, RV diastolic function remains mostly neglected. The aim of this study was to test which echocardiographic parameters best reflect RV diastolic function in mice. METHODS Pulmonary artery banding (PAB) was used to induce RV pressure overload in mice. Transthoracic echocardiography and invasive hemodynamic measurements were performed after 3 weeks in PAB and sham-operated mice. Subsequently, the hearts were investigated by histology and analyzed for gene expression. RESULTS PAB-induced pressure overload (RV systolic pressure PAB 52.6 ± 11.8 mm Hg vs sham 27.0 ± 2.7 mm Hg) resulted in RV hypertrophy and remodeling, as reflected by increased Fulton index (PAB 0.37 ± 0.05 vs sham 0.25 ± 0.02, P = .001). Masson's trichrome staining revealed increased interstitial fibrosis (PAB 12.25 ± 3.12% vs sham 3.97 ± 1.58%, P = .002). This was associated with significant systolic RV dysfunction as demonstrated by reduced contractility index and diastolic dysfunction as demonstrated by end-diastolic pressure (PAB 2.66 ± 0.83 mm Hg vs sham 1.49 ± 0.50 mm Hg, P < .001) and τ (PAB 40.0 ± 16.1 msec vs sham 13.0 ± 3.5 msec, P < .001). Messenger ribonucleic acid expression of β-myosin heavy chain, atrial and brain natriuretic peptides, collagen family members was elevated, and the sarco/endoplasmic reticulum Ca(2+)-ATPase was decreased. Echocardiography revealed significant increases in RV free wall thickness and isovolumic relaxation time and a decrease in left ventricular eccentricity index, E', and tricuspid annular plane systolic excursion. Isovolumic relaxation time and E' were significantly correlated with end-diastolic pressure (rs = 0.511 and -0.451) and τ (rs = 0.739 and -0.445, respectively). Moreover, E' was negatively correlated with the degree of RV fibrosis (rs = -0.717). CONCLUSIONS Within 3 weeks, PAB causes pressure overload-induced RV hypertrophy and remodeling with compensated systolic and diastolic dysfunction in mice. RV free wall thickness, tricuspid annular plane systolic excursion, E', E/E' ratio, and isovolumic relaxation time appear to be the most reliable echocardiographic parameters for the assessment of RV dysfunction.
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Affiliation(s)
| | - Albrecht Schmidt
- Division of Cardiology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Slaven Crnkovic
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Akylbek Sydykov
- University of Giessen and Marburg Lung Center, Excellence Cluster Cardio-Pulmonary System, Giessen, Germany
| | - Bence M Nagy
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Gabor Kovacs
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Norbert Weissmann
- University of Giessen and Marburg Lung Center, Excellence Cluster Cardio-Pulmonary System, Giessen, Germany
| | - Horst Olschewski
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Andrea Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Experimental Anesthesiology, Department of Anesthesia and Intensive Care Medicine, Medical University of Graz, Graz, Austria
| | - Grazyna Kwapiszewska
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Experimental Anesthesiology, Department of Anesthesia and Intensive Care Medicine, Medical University of Graz, Graz, Austria
| | - Leigh M Marsh
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
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High throughput phenotyping of left and right ventricular cardiomyopathy in calcineurin transgene mice. Int J Cardiovasc Imaging 2015; 31:669-79. [PMID: 25627778 DOI: 10.1007/s10554-015-0596-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/16/2015] [Indexed: 01/06/2023]
Abstract
Consistent protocols for the assessment of diastolic and systolic cardiac function to assure the comparability of existing data on preclinical models are missing. Calcineurin transgene (CN) mice are a preclinical model for hypertrophic and failing hearts. We aimed at evaluating left and right ventricular structural and functional remodeling in CN hearts with an optimized phenotyping protocol. We developed a protocol using techniques and indices comparable to those from human diagnostics for comprehensive in vivo cardiac screening using high-frequency echocardiography, Doppler, electrocardiography and cardiac magnetic resonance (CMR) techniques. We measured left and right ventricular dimensions and function, pulmonary and mitral flow pattern and the hearts electrophysiology non-invasively in <1 h per mouse. We found severe biventricular dilation and a drastic decline in performance in accordance with a condition of heart failure (HF), diastolic dysfunction and defects in electrical conduction in 8-week-old calcineurin transgenic mice. Echocardiography of the left ventricle was performed with and without anesthesia. In all cases absolute values on echocardiography compared with CMR were smaller for LV dimension and wall thickness, resulting in higher fractional shorting and ejection fraction. The study protocol described here opens opportunities to assess the added value of combined echocardiography, Doppler, CMR and ECG recording techniques for the diagnosis of biventricular cardiac pathologies i.e. of HF and to study symptom occurrence and disease progression non-invasively in high-throughput. Phenotyping CN hearts revealed new symptom occurrence and allowed insights into the diverse phenotype of hypertrophic failing hearts.
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Tsui AKY, Marsden PA, Mazer CD, Sled JG, Lee KM, Henkelman RM, Cahill LS, Zhou YQ, Chan N, Liu E, Hare GMT. Differential HIF and NOS responses to acute anemia: defining organ-specific hemoglobin thresholds for tissue hypoxia. Am J Physiol Regul Integr Comp Physiol 2014; 307:R13-25. [DOI: 10.1152/ajpregu.00411.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Tissue hypoxia likely contributes to anemia-induced organ injury and mortality. Severe anemia activates hypoxia-inducible factor (HIF) signaling by hypoxic- and neuronal nitric oxide (NO) synthase- (nNOS) dependent mechanisms. However, organ-specific hemoglobin (Hb) thresholds for increased HIF expression have not been defined. To assess organ-specific Hb thresholds for tissue hypoxia, HIF-α (oxygen-dependent degradation domain, ODD) luciferase mice were hemodiluted to mild, moderate, or severe anemia corresponding to Hb levels of 90, 70, and 50 g/l, respectively. HIF luciferase reporter activity, HIF protein, and HIF-dependent RNA levels were assessed. In the brain, HIF-1α was paradoxically decreased at mild anemia, returned to baseline at moderate anemia, and then increased at severe anemia. Brain HIF-2α remained unchanged at all Hb levels. Both kidney HIF-1α and HIF-2α increased earlier (Hb ∼70–90 g/l) in response to anemia. Liver also exhibited an early HIF-α response. Carotid blood flow was increased early (Hb ∼70, g/l), but renal blood flow remained relatively constant, only increased at Hb of 50 g/l. Anemia increased nNOS (brain and kidney) and endothelia NOS (eNOS) (kidney) levels. Whereas anemia-induced increases in brain HIFα were nNOS-dependent, our current data demonstrate that increased renal HIFα was nNOS independent. HIF-dependent RNA levels increased linearly (∼10-fold) in the brain. However, renal HIF-RNA responses (MCT4, EPO) increased exponentially (∼100-fold). Plasma EPO levels increased near Hb threshold of 90 g/l, suggesting that the EPO response is sensitive. Collectively, these observations suggest that each organ expresses a different threshold for cellular HIF/NOS hypoxia responses. This knowledge may help define the mechanism(s) by which the brain and kidney maintain oxygen homeostasis during anemia.
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Affiliation(s)
- Albert K. Y. Tsui
- Department of Anesthesia, St. Michael's Hospital, University of Toronto, Ontario, Canada
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Philip A. Marsden
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
- Department of Medicine, Division of Nephrology, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - C. David Mazer
- Department of Anesthesia, St. Michael's Hospital, University of Toronto, Ontario, Canada
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - John G. Sled
- Department of Medical Biophysics, University of Toronto, Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Keith M. Lee
- Department of Anesthesia, St. Michael's Hospital, University of Toronto, Ontario, Canada
| | - R. Mark Henkelman
- Department of Medical Biophysics, University of Toronto, Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Lindsay S. Cahill
- Department of Medical Biophysics, University of Toronto, Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Yu-Qing Zhou
- Department of Medical Biophysics, University of Toronto, Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Neville Chan
- Department of Anesthesia, St. Michael's Hospital, University of Toronto, Ontario, Canada
| | - Elaine Liu
- Department of Anesthesia, St. Michael's Hospital, University of Toronto, Ontario, Canada
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Gregory M. T. Hare
- Department of Anesthesia, St. Michael's Hospital, University of Toronto, Ontario, Canada
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Zhou YQ, Cahill LS, Wong MD, Seed M, Macgowan CK, Sled JG. Assessment of flow distribution in the mouse fetal circulation at late gestation by high-frequency Doppler ultrasound. Physiol Genomics 2014; 46:602-14. [PMID: 24963005 DOI: 10.1152/physiolgenomics.00049.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This study used high-frequency ultrasound to evaluate the flow distribution in the mouse fetal circulation at late gestation. We studied 12 fetuses (embryonic day 17.5) from 12 pregnant CD1 mice with 40 MHz ultrasound to assess the flow in 11 vessels based on Doppler measurements of blood velocity and M-mode measurements of diameter. Specifically, the intrahepatic umbilical vein (UVIH), ductus venosus (DV), foramen ovale (FO), ascending aorta (AA), main pulmonary artery (MPA), ductus arteriosus (DA), descending thoracic aorta (DTA), common carotid artery (CCA), inferior vena cava (IVC), and right and left superior vena cavae (RSVC, LSVC) were examined, and anatomically confirmed by micro-CT. The mouse fetal circulatory system was found to be similar to that of the humans in terms of the major circuit and three shunts, but characterized by bilateral superior vena cavae and a single umbilical artery. The combined cardiac output (CCO) was 1.22 ± 0.05 ml/min, with the left ventricle (flow in AA) contributing 47.8 ± 2.3% and the right ventricle (flow in MPA) 52.2 ± 2.3%. Relative to the CCO, the flow percentages were 13.6 ± 1.0% for the UVIH, 10.4 ± 1.1% for the DV, 35.6 ± 2.4% for the DA, 41.9 ± 2.6% for the DTA, 3.8 ± 0.3% for the CCA, 29.5 ± 2.2% for the IVC, 12.7 ± 1.0% for the RSVC, and 9.9 ± 0.9% for the LSVC. The calculated flow percentage was 16.6 ± 3.4% for the pulmonary circulation and 31.2 ± 5.3% for the FO. In conclusion, the flow in mouse fetal circulation can be comprehensively evaluated with ultrasound. The baseline data of the flow distribution in normal mouse fetus serve as the reference range for future studies.
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Affiliation(s)
- Yu-Qing Zhou
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada;
| | - Lindsay S Cahill
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Michael D Wong
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Mike Seed
- Division of Cardiology, Department of Paediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Christopher K Macgowan
- Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada; and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - John G Sled
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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Lanz B, Poitry-Yamate C, Gruetter R. Image-derived input function from the vena cava for 18F-FDG PET studies in rats and mice. J Nucl Med 2014; 55:1380-8. [PMID: 24914058 DOI: 10.2967/jnumed.113.127381] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 04/02/2014] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Measurement of arterial input function is a restrictive aspect for quantitative (18)F-FDG PET studies in rodents because of their small total blood volume and the related difficulties in withdrawing blood. METHODS In the present study, we took advantage of the high spatial resolution of a recent dedicated small-animal scanner to extract the input function from the (18)F-FDG PET images in Sprague-Dawley rats (n = 4) and C57BL/6 mice (n = 5), using the vena cava. In the rat experiments, the validation of the image-derived input function (IDIF) method was made using an external microvolumetric blood counter as reference for the determination of the arterial input function, the measurement of which was confirmed by additional manually obtained blood samples. Correction for tracer bolus dispersion in blood between the vena cava and the arterial tree was applied. In addition, simulation studies were undertaken to probe the impact of the different IDIF extraction approaches on the determined cerebral metabolic rate of glucose (CMRGlc). In the mice measurements, the IDIF was used to compute the CMRGlc, which was compared with previously reported values, using the Patlak approach. RESULTS The presented IDIF from the vena cava showed a robust determination of CMRGlc using either the compartmental modeling or the Patlak approach, even without bolus dispersion correction or blood sampling, with an underestimation of CMRGlc of 7% ± 16% as compared with the reference data. Using this approach in the mice experiments, we measured a cerebral metabolic rate in the cortex of 0.22 ± 0.10 μmol/g/min (mean ± SD), in good agreement with previous (18)F-FDG studies in the mouse brain. In the rat experiments, dispersion correction of the IDIF and additional scaling of the IDIF using a single manual blood sample enabled an optimized determination of CMRGlc, with an underestimation of 6% ± 7%. CONCLUSION The vena cava time-activity curve is therefore a minimally invasive alternative for the measurement of the (18)F-FDG input function in rats and mice, without the complications associated with repetitive blood sampling.
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Affiliation(s)
- Bernard Lanz
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Carole Poitry-Yamate
- Center for Biomedical Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland Center for Biomedical Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland Department of Radiology, University of Lausanne, Lausanne, Switzerland; and Department of Radiology, University of Geneva, Geneva, Switzerland
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Domínguez E, Ruberte J, Ríos J, Novellas R, Del Alamo MMR, Navarro M, Espada Y. Non-invasive in vivo measurement of cardiac output in C57BL/6 mice using high frequency transthoracic ultrasound: evaluation of gender and body weight effects. Int J Cardiovasc Imaging 2014; 30:1237-44. [PMID: 24852337 DOI: 10.1007/s10554-014-0454-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 05/16/2014] [Indexed: 01/13/2023]
Abstract
Even though mice are being increasingly used as models for human cardiovascular diseases, non-invasive monitoring of cardiovascular parameters such as cardiac output (CO) in this species is challenging. In most cases, the effects of gender and body weight (BW) on these parameters have not been studied. The objective of this study was to provide normal reference values for CO in C57BL/6 mice, and to describe possible gender and/or BW associated differences between them. We used 30-MHz transthoracic Doppler ultrasound to measure hemodynamic parameters in the ascending aorta [heart rate (HR), stroke volume (SV), stroke index (SI), CO, and cardiac index (CI)] in ten anesthetized mice of either sex. No differences were found for HR, SV, and CO. Both SI and CI were statistically lower in males. However, after normalization for BW, these differences disappeared. These results suggest that if comparisons of cardiovascular parameters are to be made between male and female mice, values should be standardized for BW.
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Affiliation(s)
- Elisabet Domínguez
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Edifici V, Campus, 08193, Barcelona, Spain,
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Meoli L, Isensee J, Zazzu V, Nabzdyk CS, Soewarto D, Witt H, Foryst-Ludwig A, Kintscher U, Noppinger PR. Sex- and age-dependent effects of Gpr30 genetic deletion on the metabolic and cardiovascular profiles of diet-induced obese mice. Gene 2014; 540:210-6. [PMID: 24582972 DOI: 10.1016/j.gene.2014.02.036] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 12/09/2013] [Accepted: 02/19/2014] [Indexed: 12/26/2022]
Abstract
The G protein-coupled receptor 30 (GPR30) has been claimed as an estrogen receptor. However, the literature reports controversial findings and the physiological function of GPR30 is not fully understood yet. Consistent with studies assigning a role of GPR30 in the cardiovascular and metabolic systems, GPR30 expression has been reported in small arterial vessels, pancreas and chief gastric cells of the stomach. Therefore, we hypothesized a role of GPR30 in the onset and progression of cardiovascular and metabolic diseases. In order to test our hypothesis, we investigated the effects of a high-fat diet on the metabolic and cardiovascular profiles of Gpr30-deficient mice (GPR30-lacZ mice). We found that GPR30-lacZ female, rather than male, mice had significant lower levels of HDL along with an increase in fat liver accumulation as compared to control mice. However, two indicators of cardiac performance assessed by echocardiography, ejection fraction and fractional shortening were both decreased in an age-dependent manner only in Gpr30-lacZ male mice. Collectively our results point to a potential role of Gpr30 in preserving lipid metabolism and cardiac function in a sex- and age-dependent fashion.
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Affiliation(s)
- Luca Meoli
- Center for Cardiovascular Research-Charité, Hessische Str. 3-4, 10115 Berlin, Germany.
| | - Jörg Isensee
- Center for Cardiovascular Research-Charité, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Valeria Zazzu
- Center for Cardiovascular Research-Charité, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Christoph S Nabzdyk
- Center for Cardiovascular Research-Charité, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Dian Soewarto
- Center for Cardiovascular Research-Charité, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Henning Witt
- Center for Cardiovascular Research-Charité, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Anna Foryst-Ludwig
- Center for Cardiovascular Research-Charité, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Ulrich Kintscher
- Center for Cardiovascular Research-Charité, Hessische Str. 3-4, 10115 Berlin, Germany
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Mutation in integrin-linked kinase (ILK(R211A)) and heat-shock protein 70 comprise a broadly cardioprotective complex. PLoS One 2013; 8:e77331. [PMID: 24260102 PMCID: PMC3832499 DOI: 10.1371/journal.pone.0077331] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 08/31/2013] [Indexed: 12/14/2022] Open
Abstract
Rationale Integrin-linked kinase (ILK) has been proposed as a novel molecular target that has translational potential in diverse cardiac diseases, since its upregulation promotes a broadly cardioprotective phenotype. However, ILK has been implicated as both a cardioprotective and oncogenic target, which imposes therapeutic constraints that are generally relevant to the translational potential of many kinases. Objective To study the cardioprotective properties of the activation-resistant, non-oncogenic, mutation of ILK (ILKR211A) against experimental MI invivo and Doxorubicin induced apoptosis invitro and it’s relationships to stress induced heat shock proteins. Methods/Results The transgenic mouse heart over-expressing a point mutation in the ILK pleckstrin homology (PH) domain (TgR211A) exhibits a highly cardioprotective phenotype based on LAD-ligation-induced MI reduction invivo, and on protection against doxorubicin (DOX)-induced cardiomyocyte apoptosis when overexpressed in human induced pluripotent stem cell (iPS)-derived cardiomyocytes invitro. Intriguingly, the degree of cardioprotection seen with the ILKR211A mutation exceeded that with the ILKS343D mutation. Microarray and immunoprecipitation analyses revealed upregulation of expression levels and specific binding of ILKWT, ILKS343D and ILKR211A to both constitutively active heat-shock protein 70 (Hsc70) and inducible Hsp70 in response to MI, and to acute ILK overexpression in iPSC-cardiomyocytes. ILK-mediated cardioprotection was shown to depend upon Hsp70 ATPase activity. Conclusions These findings indicate that wild type ILK and the non-oncogenic ILKR211A mutation comprise a cardioprotective module with Hsp/c70. These results advance a novel target discovery theme in which kinase mutations can be safely engineered to enhance cardioprotective effects.
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Wu J, Zhou YQ, Zou Y, Henkelman M. Evaluation of bi-ventricular coronary flow patterns using high-frequency ultrasound in mice with transverse aortic constriction. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:2053-2065. [PMID: 23932279 DOI: 10.1016/j.ultrasmedbio.2013.04.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 03/15/2013] [Accepted: 04/28/2013] [Indexed: 06/02/2023]
Abstract
Using high-frequency color and pulsed Doppler ultrasound, we evaluated the flow patterns of the left (LCA), septal (SCA) and right (RCA) coronary arteries in mice with and without transverse aortic constriction (TAC). Fifty-two male C57BL/6J mice were subjected to TAC or a corresponding sham operation. At 2 and 8 wk post-surgery, Doppler flow spectra from the three coronary arteries, together with morphologic and functional parameters of the left and right ventricles, were measured. Histology was performed to evaluate myocyte size and neo-angiogenesis in both ventricles. In sham-operated mice, the LCA and SCA both exhibited low-flow waveforms during systole and dominantly higher-flow waveforms during diastole. The RCA exhibited generally lower flow velocity, with similar systolic and diastolic waveforms. TAC significantly increased the systolic flow velocities of all coronary arteries, but enhanced the flow mainly in the LCA and SCA. In the left ventricle, coronary flow reserve was partially preserved 2 wk post-TAC, but decreased at 8 wk, consistent with changes in neo-angiogenesis and systolic function. In contrast, no significant change was found in the coronary flow reserve, structure or function of the right ventricle. This study has established a protocol for evaluating the flow pattern in three principal coronary arteries in mice using Doppler ultrasound and illustrated the difference among three vessels at baseline. In mice with TAC, the difference in the associating pattern of coronary flow dynamics with the myocardial structure and function between the left and right ventricles provides further insights into ventricular remodeling under pressure overload.
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Affiliation(s)
- Jian Wu
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Canada; Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Shanghai, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, China
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Abstract
BACKGROUND Notch1 signaling controls the cardiac adaptation to stress. We therefore aimed to validate whether olmesartan, a widely used angiotensin II type 1 receptor blocker, ameliorates cardiac remodeling and dysfunction via delta-like ligand 4 (DLL4)/Notch1 pathway in mice with chronic pressure overload. METHODS Cardiac pressure overload was produced by transverse aortic constriction (TAC). A total of 35 wide-type C57BL/6J mice were randomly divided into sham group, TAC group, TAC + olmesartan group, and TAC + olmsartan + DAPT group (DAPT: γ-secretase inhibitor, Notch signaling inhibitor). Saline (10 mL·kg(-1)·d(-1)) or the same volume of olmesartan liquor (3 mg·kg(-1) d(-1)) was administered by gavage, and DAPT (10 μmole·kg(-1)·d(-1)) by peritoneal injection. After 28 days of treatment, cardiac hemodynamics, echocardiography, and histology were evaluated, followed by quantitative polymerase chain reaction of fetal gene (ANP and SAA) expression. Notch1-related proteins and ERK1/2 were examined by western blot, and the serum level of angiotensin II was determined by means of enzyme-linked immunosorbent assay kits. RESULTS Persistent pressure overload-induced left ventricular hypertrophy, dysfunction, fibrosis, and microcirculation dysfunction, together with the upregulation of angiotensin II, ERK1/2, and fetal gene expression. By the activation of DLL4/Notch1, olmesartan decreased left ventricular hypertrophy and fibrosis, preserved cardiac function, and improved capillary density and coronary perfusion. All these curative effects were suppressed by pharmacological blockade of Notch signaling with DAPT. CONCLUSIONS Our findings identify a heretofore unknown pharmacological mechanism that olmesartan improves cardiac remodeling and function via DLL4/Notch1 pathway activation in mice with chronic pressure overload, which may present a new therapeutic target for hypertension.
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Kelsey L, Flenniken AM, Qu D, Funnell APW, Pearson R, Zhou YQ, Voronina I, Berberovic Z, Wood G, Newbigging S, Weiss ES, Wong M, Quach I, Yeh SYS, Deshwar AR, Scott IC, McKerlie C, Henkelman M, Backx P, Simpson J, Osborne L, Rossant J, Crossley M, Bruneau B, Adamson SL. ENU-induced mutation in the DNA-binding domain of KLF3 reveals important roles for KLF3 in cardiovascular development and function in mice. PLoS Genet 2013; 9:e1003612. [PMID: 23874215 PMCID: PMC3708807 DOI: 10.1371/journal.pgen.1003612] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 05/22/2013] [Indexed: 12/23/2022] Open
Abstract
KLF3 is a Krüppel family zinc finger transcription factor with widespread tissue expression and no previously known role in heart development. In a screen for dominant mutations affecting cardiovascular function in N-ethyl-N-nitrosourea (ENU) mutagenized mice, we identified a missense mutation in the Klf3 gene that caused aortic valvular stenosis and partially penetrant perinatal lethality in heterozygotes. All homozygotes died as embryos. In the first of three zinc fingers, a point mutation changed a highly conserved histidine at amino acid 275 to arginine (Klf3H275R). This change impaired binding of the mutant protein to KLF3's canonical DNA binding sequence. Heterozygous Klf3H275R mutants that died as neonates had marked biventricular cardiac hypertrophy with diminished cardiac chambers. Adult survivors exhibited hypotension, cardiac hypertrophy with enlarged cardiac chambers, and aortic valvular stenosis. A dominant negative effect on protein function was inferred by the similarity in phenotype between heterozygous Klf3H275R mutants and homozygous Klf3 null mice. However, the existence of divergent traits suggested the involvement of additional interactions. We conclude that KLF3 plays diverse and important roles in cardiovascular development and function in mice, and that amino acid 275 is critical for normal KLF3 protein function. Future exploration of the KLF3 pathway provides a new avenue for investigating causative factors contributing to cardiovascular disorders in humans. Cardiac defects are among the most common malformations in humans. Most causative genetic mutations remain unknown. To discover new causative genes important in cardiovascular development and function, we examined 1770 mice with randomly mutated genes and found a mutant with aortic valvular stenosis, and increased risk of fetal and neonatal death. Using linkage analysis and sequencing, we identified a protein-altering point mutation in the gene regulatory protein KLF3. Mice that survived into adulthood with one mutant copy of the Klf3 gene had low arterial blood pressure, enlarged hearts, and increased mortality due to heart failure. When both copies of the Klf3 gene was mutant, then embryos had heart defects, and all died before birth. KLF3 had no previously known role in heart development so to confirm these findings, we (1) knocked down klf3 expression in zebrafish embryos and (2) examined mice with a mutation that effectively eliminated the KLF3 protein. In both cases, cardiovascular dysfunction was observed. In conclusion, we have discovered that KLF3 plays diverse and important roles in cardiovascular development and function in mice. Future exploration of the KLF3 pathway provides a new avenue for investigating causative factors contributing to cardiovascular disorders in humans.
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Affiliation(s)
- Lois Kelsey
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
| | - Ann M. Flenniken
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
| | - Dawei Qu
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
| | - Alister P. W. Funnell
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Richard Pearson
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Yu-Qing Zhou
- Mouse Imaging Centre, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Irina Voronina
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
| | - Zorana Berberovic
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
| | - Geoffrey Wood
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Susan Newbigging
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Edward S. Weiss
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
| | - Michael Wong
- Mouse Imaging Centre, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Ivan Quach
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
| | - S. Y. Sandy Yeh
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Ashish R. Deshwar
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Ian C. Scott
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Richard Lewar Centre of Excellence, Toronto, Ontario, Canada
| | - Colin McKerlie
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Mark Henkelman
- Mouse Imaging Centre, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Peter Backx
- Heart and Stroke Richard Lewar Centre of Excellence, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Jeremy Simpson
- Heart and Stroke Richard Lewar Centre of Excellence, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Lucy Osborne
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Janet Rossant
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Merlin Crossley
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Benoit Bruneau
- Gladstone Institute of Cardiovascular Disease, Department of Pediatrics, and Cardiovascular Research Institute, University of California, San Francisco, California, United States of America
| | - S. Lee Adamson
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
- Centre for Modeling Human Disease, Toronto Centre for Phenogenomics, Toronto, Ontario, Canada
- Heart and Stroke Richard Lewar Centre of Excellence, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Adams D, Baldock R, Bhattacharya S, Copp AJ, Dickinson M, Greene NDE, Henkelman M, Justice M, Mohun T, Murray SA, Pauws E, Raess M, Rossant J, Weaver T, West D. Bloomsbury report on mouse embryo phenotyping: recommendations from the IMPC workshop on embryonic lethal screening. Dis Model Mech 2013; 6:571-9. [PMID: 23519032 PMCID: PMC3634642 DOI: 10.1242/dmm.011833] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Identifying genes that are important for embryo development is a crucial first step towards understanding their many functions in driving the ordered growth, differentiation and organogenesis of embryos. It can also shed light on the origins of developmental disease and congenital abnormalities. Current international efforts to examine gene function in the mouse provide a unique opportunity to pinpoint genes that are involved in embryogenesis, owing to the emergence of embryonic lethal knockout mutants. Through internationally coordinated efforts, the International Knockout Mouse Consortium (IKMC) has generated a public resource of mouse knockout strains and, in April 2012, the International Mouse Phenotyping Consortium (IMPC), supported by the EU InfraCoMP programme, convened a workshop to discuss developing a phenotyping pipeline for the investigation of embryonic lethal knockout lines. This workshop brought together over 100 scientists, from 13 countries, who are working in the academic and commercial research sectors, including experts and opinion leaders in the fields of embryology, animal imaging, data capture, quality control and annotation, high-throughput mouse production, phenotyping, and reporter gene analysis. This article summarises the outcome of the workshop, including (1) the vital scientific importance of phenotyping embryonic lethal mouse strains for basic and translational research; (2) a common framework to harmonise international efforts within this context; (3) the types of phenotyping that are likely to be most appropriate for systematic use, with a focus on 3D embryo imaging; (4) the importance of centralising data in a standardised form to facilitate data mining; and (5) the development of online tools to allow open access to and dissemination of the phenotyping data.
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Affiliation(s)
- David Adams
- Wellcome Trust Sanger Institute, Cambridge, CB10 1SA, UK
| | | | | | - Andrew J. Copp
- UCL Institute of Child Health, Gower Street, London, WC1E 6BT, UK
| | | | | | | | | | - Timothy Mohun
- MRC National Institute for Medical Research, London, NW7 1AA, UK
| | | | - Erwin Pauws
- UCL Institute of Child Health, Gower Street, London, WC1E 6BT, UK
| | - Michael Raess
- Helmholtz Zentrum Munich and Infrafrontier, Ingolstädter Landstraße 1 85764 Neuherberg, Munich, Germany
| | | | - Tom Weaver
- MRC Harwell, Harwell Science and Innovation Campus, Oxford, OX11 0RD, UK
| | - David West
- CHORI, 5700 Martin Luther King Jr Way, Oakland, CA 94609, USA
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Qiu W, Yu Y, Chabok HR, Liu C, Tsang FK, Zhou Q, Shung KK, Zheng H, Sun L. A flexible annular-array imaging platform for micro-ultrasound. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:178-186. [PMID: 23287923 PMCID: PMC3738186 DOI: 10.1109/tuffc.2013.2548] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Micro-ultrasound is an invaluable imaging tool for many clinical and preclinical applications requiring high resolution (approximately several tens of micrometers). Imaging systems for micro-ultrasound, including single-element imaging systems and linear-array imaging systems, have been developed extensively in recent years. Single-element systems are cheaper, but linear-array systems give much better image quality at a higher expense. Annular-array-based systems provide a third alternative, striking a balance between image quality and expense. This paper presents the development of a novel programmable and real-time annular-array imaging platform for micro-ultrasound. It supports multi-channel dynamic beamforming techniques for large-depth-of-field imaging. The major image processing algorithms were achieved by a novel field-programmable gate array technology for high speed and flexibility. Real-time imaging was achieved by fast processing algorithms and high-speed data transfer interface. The platform utilizes a printed circuit board scheme incorporating state-of-the-art electronics for compactness and cost effectiveness. Extensive tests including hardware, algorithms, wire phantom, and tissue mimicking phantom measurements were conducted to demonstrate good performance of the platform. The calculated contrast-to-noise ratio (CNR) of the tissue phantom measurements were higher than 1.2 in the range of 3.8 to 8.7 mm imaging depth. The platform supported more than 25 images per second for real-time image acquisition. The depth-of-field had about 2.5-fold improvement compared to single-element transducer imaging.
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Affiliation(s)
- Weibao Qiu
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China
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37
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Olson JD, Walb MC, Moore JE, Attia A, Sawyer HL, McBride JE, Wheeler KT, Miller MS, Munley MT. A gated-7T MRI technique for tracking lung tumor development and progression in mice after exposure to low doses of ionizing radiation. Radiat Res 2012; 178:321-7. [PMID: 22950352 DOI: 10.1667/rr2800.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A gated-7T magnetic resonance imaging (MRI) application is described that can accurately and efficiently measure the size of in vivo mouse lung tumors from ∼0.1 mm(3) to >4 mm(3). This MRI approach fills a void in radiation research because the technique can be used to noninvasively measure the growth rate of lung tumors in large numbers of mice that have been irradiated with low doses (<50 mGy) without the additional radiation exposure associated with planar X ray, CT or PET imaging. High quality, high resolution, reproducible images of the mouse thorax were obtained in ∼20 min using: (1) a Bruker 7T micro-MRI scanner equipped with a 60 mm inner diameter gradient insert capable of generating a maximum gradient of 1000 mT/m; (2) a 35 mm inner diameter quadrature radiofrequency volume coil; and (3) an electrocardiogram and respiratory gated Fast Low Angle Shot (FLASH) pulse sequence. The images had an in-plane image resolution of 98 μm and a 0.5 mm slice thickness. Tumor diameter measured by MRI was highly correlated (R(2) = 0.97) with the tumor diameter measured by electronic calipers. Data generated with an initiation/promotion mouse model of lung carcinogenesis and this MRI technique demonstrated that mice exposed to 4 weekly fractions of 10, 30 or 50 mGy of CT radiation had the same lung tumor growth rate as that measured in sham-irradiated mice. In summary, this high-field, double-gated MRI approach is an efficient way of quantitatively tracking lung tumor development and progression after exposure to low doses of ionizing radiation.
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Affiliation(s)
- John D Olson
- Center for Biomolecular Imaging, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, USA
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38
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Qiu W, Yu Y, Tsang F, Sun L. An FPGA-based open platform for ultrasound biomicroscopy. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2012; 59:1432-1442. [PMID: 22828839 DOI: 10.1109/tuffc.2012.2344] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ultrasound biomicroscopy (UBM) has been extensively applied to preclinical studies in small animal models. Individual animal study is unique and requires different utilization of the UBM system to accommodate different transducer characteristics, data acquisition strategies, signal processing, and image reconstruction methods. There is a demand for a flexible and open UBM platform to allow users to customize the system for various studies and have full access to experimental data. This paper presents the development of an open UBM platform (center frequency 20 to 80 MHz) for various preclinical studies. The platform design was based on a field-programmable gate array (FPGA) embedded in a printed circuit board to achieve B-mode imaging and directional pulsed-wave Doppler. Instead of hardware circuitry, most functions of the platform, such as filtering, envelope detection, and scan conversion, were achieved by FPGA programs; thus, the system architecture could be easily modified for specific applications. In addition, a novel digital quadrature demodulation algorithm was implemented for fast and accurate Doppler profiling. Finally, test results showed that the platform could offer a minimum detectable signal of 25 μV, allowing a 51 dB dynamic range at 47 dB gain, and real-time imaging at more than 500 frames/s. Phantom and in vivo imaging experiments were conducted and the results demonstrated good system performance.
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Affiliation(s)
- Weibao Qiu
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China
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39
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Wu J, You J, Jiang G, Li L, Guan A, Ye Y, Li D, Gong H, Ge J, Zou Y. Noninvasive estimation of infarct size in a mouse model of myocardial infarction by echocardiographic coronary perfusion. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2012; 31:1111-1121. [PMID: 22733860 DOI: 10.7863/jum.2012.31.7.1111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVES Animal models of myocardial infarction (MI) are widely used not only in analyses of the mechanisms but also in testing the efficacy of therapeutic strategies for the disease. It is therefore critically important but almost impossible to exactly evaluate the validity of coronary artery ligation in a mouse model of MI except by anatomic and histologic analyses. We explored a noninvasive method to estimate MI through analyses of coronary perfusion by transthoracic echocardiography in mice before and 1 day after ligation of the left anterior descending coronary artery. METHODS Transthoracic echocardiography-based cardiac function, geometry, and coronary perfusion, electrocardiographic findings, and serum troponin I levels were examined in C57BL6/J mice subjected to left anterior descending artery ligation. The histologic infarct size was confirmed by staining the heart with 2,3,5-triphenyltetrazolium chloride. RESULTS Among all parameters, the postoperative hyperemic peak diastolic velocity and coronary flow reserve were most correlated with infarct size (R² = .8028 and .5825, respectively; both P < .0001). With an infarct size of 30% or greater indicating successful ligation and less than 30% indicating unsuccessful ligation, receiver operating characteristic curve analysis showed that the postoperative hyperemic peak diastolic velocity and coronary flow reserve most effectively indicated the infarct size level with optimal cutoff values of 480.16 mm/s and 1.89, respectively. Furthermore, impaired cardiac function, an eccentrically expanded left ventricle, typical pathologic electrocardiographic findings, and elevated troponin I levels were observed most often in the mice with an impaired hyperemic peak diastolic velocity and coronary flow reserve. CONCLUSIONS The echocardiographic hyperemic peak diastolic velocity and coronary flow reserve can estimate the histologic infarct size in mice with coronary occlusion.
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Affiliation(s)
- Jian Wu
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Institutes of Biomedical Sciences, Fudan University, 180 Feng Lin Rd 200032 Shanghai, China
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40
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Wu J, You J, Li L, Ma H, Jia J, Jiang G, Chen Z, Ye Y, Gong H, Bu L, Ge J, Zou Y. Early estimation of left ventricular systolic pressure and prediction of successful aortic constriction in a mouse model of pressure overload by ultrasound biomicroscopy. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:1030-1039. [PMID: 22425378 DOI: 10.1016/j.ultrasmedbio.2012.01.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Revised: 12/29/2011] [Accepted: 01/22/2012] [Indexed: 05/31/2023]
Abstract
Elevation of left ventricular end-systolic pressure (LVESP) and hypertrophic response in mice varies after transverse aorta constriction (TAC). Micromanometric catheterization, conventionally used to select mice with successful TAC, is invasive and nonreusable. We aimed to establish noninvasive imaging protocols for early estimation of successful TAC by ultrasound biomicroscopy (UBM). Out of 55 C57BL/6J mice, we randomly selected 45 as TAC group and 10 as controls. UMB was performed before TAC and, at day 3 and day 14, after TAC. In all mice, LVESP was measured with a Millar conductance catheter at day 14. With LVESP ≥ 150 mm Hg set as indicator of successful TAC (TAC+) and LVESP < 150 mm Hg as unsuccessful (TAC-), receiver operating characteristic curve analysis demonstrated that postoperative inner diameter at aortic banding site (IDb), peak flow velocity at aortic banding site (PVb) and peak flow velocity of right/left common carotid artery (PVr/l) at day 3 served as most effective predictors for LVESP at day 14 (area under curve = 0.9016, 0.9143, 0.8254, respectively. p < 0.01 for all). Among all UBM parameters at day 3, IDb, PVb, right common carotid artery peak flow velocity (PVr) and PVr/l correlated best with LVESP at day 14 (R(2) = 0.5740, 0.6549, 0.5208, 0.2274, respectively. p < 0.01 for all). Furthermore, IDb, PVb, and PVr/l at day 3 most effectively predict long-term cardiac hypertrophy, using the cut-off values of 0.45 mm, 2698.00 mm/s, 3.08, respectively. UBM can be a noninvasive and effective option for early prediction of successful TAC.
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Affiliation(s)
- Jian Wu
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China
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41
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Martin TP, Robinson E, Harvey AP, MacDonald M, Grieve DJ, Paul A, Currie S. Surgical optimization and characterization of a minimally invasive aortic banding procedure to induce cardiac hypertrophy in mice. Exp Physiol 2012; 97:822-32. [PMID: 22447975 DOI: 10.1113/expphysiol.2012.065573] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Left ventricular pressure overload in response to aortic banding is an invaluable model for studying progression of cardiac hypertrophy and transition to heart failure. Traditional aortic banding has recently been superceded by minimally invasive transverse aortic banding (MTAB), which does not require ventilation so is less technically challenging. Although the MTAB approach is superior, few laboratories have documented success, and minimal information on the model is available. The aim of this study was to optimize conditions for MTAB and to characterize the development and progression of cardiac hypertrophy. Isofluorane proved the most suitable anaesthetic for MTAB surgery in mice, and 1 week after surgery the MTAB animals showed significant increases in systolic blood pressure (MTAB 110 ± 6 mmHg versus sham 78 ± 3 mmHg, n = 7, P < 0.0001) and heart weight to body weight ratio (MTAB 6.2 ± 0.2 versus sham 5.1 ± 0.1, n = 12, P < 0.001), together with systolic (e.g. fractional shortening, MTAB 31.7 ± 1% versus sham 36.6 ± 1.4%, P = 0.01) and diastolic dysfunction (e.g. left ventricular end-diastolic pressure, MTAB 12.7 ± 1.0 mmHg versus sham 6.7 ± 0.8 mmHg, P < 0.001). Leucocyte infiltration to the heart was evident after 1 week in MTAB hearts, signifying an inflammatory response. More pronounced remodelling was observed 4 weeks postsurgery (heart weight to body weight ratio, MTAB 9.1 ± 0.6 versus sham 4.6 ± 0.04, n = 10, P < 0.0001) and fractional shortening was further decreased (MTAB 24.3 ± 2.5% versus sham 43.6 ± 1.7%, n = 10, P = 0.003), together with a significant increase in cardiac fibrosis and further cardiac inflammation. Our findings demonstrate that MTAB is a relevant experimental model for studying development and progression of cardiac hypertrophy, which will be highly valuable for future studies examining potential novel therapeutic interventions in this setting.
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Affiliation(s)
- Tamara P Martin
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, UK
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42
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Non- invasive in vivo analysis of a murine aortic graft using high resolution ultrasound microimaging. Eur J Radiol 2012; 81:244-9. [DOI: 10.1016/j.ejrad.2010.12.083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 12/22/2010] [Indexed: 11/23/2022]
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Denis M, Marcinkiewicz J, Zaid A, Gauthier D, Poirier S, Lazure C, Seidah NG, Prat A. Gene inactivation of proprotein convertase subtilisin/kexin type 9 reduces atherosclerosis in mice. Circulation 2012; 125:894-901. [PMID: 22261195 DOI: 10.1161/circulationaha.111.057406] [Citation(s) in RCA: 173] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND The proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes independently of its enzymatic activity the degradation of the low-density lipoprotein (LDL) receptor. PCSK9 gain of function in humans leads to autosomal dominant hypercholesterolemia, whereas the absence of functional PCSK9 results in ≈7-fold lower levels of LDL cholesterol. This suggests that lowering PCSK9 may protect against atherosclerosis. METHODS AND RESULTS We investigated the role of PCSK9 in atherosclerosis in C57BL/6 wild-type (WT), apolipoprotein E-deficient, and LDL receptor-deficient mouse models. Circulating cholesterol levels, fast protein liquid chromatography profiles, aortic cholesteryl esters (CE), and plaque sizes were determined. Intima-media thicknesses were measured by ultrasound biomicroscopy. First, mice expressing null (knockout [KO]), normal (WT), or high (transgenic [Tg]) levels of PCSK9 were fed a 12-month Western diet. KO mice accumulated 4-fold less aortic CE than WT mice, whereas Tg mice exhibited high CE and severe aortic lesions. Next we generated apolipoprotein E-deficient mice, known to spontaneously develop lesions, that expressed null (KO/e), normal (WT/e), or high (Tg/e) levels of PCSK9. After a 6-month regular diet, KO/e mice showed a 39% reduction compared with WT/e mice in aortic CE accumulation, whereas Tg/e mice showed a 137% increase. Finally, LDL receptor-deficient mice expressing no (KO/L), normal (WT/L), or high (Tg/L) levels of PCSK9 were fed a Western diet for 3 months. KO/L and Tg/L mice exhibited levels of plasma cholesterol and CE accumulation similar to those of WT/L mice, suggesting that PCSK9 modulates atherosclerosis mainly via the LDL receptor. CONCLUSIONS Altogether, our results show a direct relationship between PCSK9 and atherosclerosis. PCSK9 overexpression is proatherogenic, whereas its absence is protective.
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Affiliation(s)
- Maxime Denis
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, 110 Pine Ave W, Montreal, QC, H2W 1R7, Canada
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Zhang L, Lu D, Zhang W, Quan X, Dong W, Xu Y, Zhang L. Cardioprotection by Hepc1 in cTnT(R141W) transgenic mice. Transgenic Res 2011; 21:867-78. [PMID: 22198484 DOI: 10.1007/s11248-011-9582-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 12/09/2011] [Indexed: 12/11/2022]
Abstract
Hepcidin 1 (Hepc1) is a peptide hormone secreted by the liver in response to iron loading. It is expressed in the heart and is thought to play a role in the regulation of iron homeostasis in an autocrine and paracrine fashion. We have shown that expression of Hepc1 is strongly down-regulated in the heart of the cTnT(R141W) transgenic mouse model of dilated cardiomyopathy (DCM) at 3 months of age. Transgenic mice with heart tissue-specific Hepc1 expression alone or in combination with the cTnT(R141W) mutation were produced to study the effects of Hepc1 on DCM. Transgenic expression of Hepc1 was found to be nonlethal and resulted in decreased mortality in cTnT(R141W) transgenic mice, from 29.6 to 7.4%(n = 27; P < 0.05), through 7 months of age. Expression of Hepc1 also brought about increases in the left ventricular wall, as well as ejection fraction and fractional shortening. In addition, the expression of Hepc1 inhibited the fibrosis and ultra-structural alterations seen in cTnT(R141W) transgenic mice. Furthermore, transgenic expression of Hepc1 restored the iron level and phosphorylation level of extracellular signal-regulated kinases 1/2 (ERK1/2) in the heart tissues of cTnT(R141W) transgenic mice. It was concluded that transgenic expression of Hepc1 compensated for the loss of Hepc1 expression and the release of iron and brought about a marked improvement in the pathologic phenotype of DCM, in which the ERK1/2 signal pathway might play an important role.
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Affiliation(s)
- Li Zhang
- Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medical Center, Peking Union Medical College, Panjiayuan Nanli, Chaoyang District, Beijing 100021, People's Republic of China
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Chugh BP, Bishop J, Zhou YQ, Wu J, Henkelman RM, Sled JG. Robust method for 3D arterial spin labeling in mice. Magn Reson Med 2011; 68:98-106. [PMID: 22102489 DOI: 10.1002/mrm.23209] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 08/15/2011] [Accepted: 08/16/2011] [Indexed: 11/12/2022]
Abstract
Arterial spin labeling is a versatile perfusion quantification methodology, which has the potential to provide accurate characterization of cerebral blood flow (CBF) in mouse models. However, a paucity of physiological data needed for accurate modeling, more stringent requirements for gradient performance, and strong artifacts introduced by magnetization transfer present special challenges for accurate CBF mapping in the mouse. This article describes robust mapping of CBF over three-dimensional brain regions using amplitude-modulated continuous arterial spin labeling. To provide physiological data for CBF modeling, the carotid artery blood velocity distribution was characterized using pulsed-wave Doppler ultrasound. These blood velocity measurements were used in simulations that optimize inversion efficiency for parameters meeting MRI gradient duty cycle constraints. A rapid slice positioning algorithm was developed and evaluated to provide accurate positioning of the labeling plane. To account for enhancement of T(1) due to magnetization transfer, a binary spin bath model of magnetization transfer was used to provide a more accurate estimate of CBF. Finally, a study of CBF was conducted on 10 mice with findings of highly reproducible inversion efficiency (mean ± standard-error-of-the-mean, 0.67 ± 0.03), statistically significant variation in CBF over 12 brain regions (P < 0.0001) and a mean ± standard-error-of-the-mean whole brain CBF of 219 ± 6 mL/100 g/min.
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Affiliation(s)
- Brige Paul Chugh
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Tomita H, Hagaman J, Friedman MH, Maeda N. Relationship between hemodynamics and atherosclerosis in aortic arches of apolipoprotein E-null mice on 129S6/SvEvTac and C57BL/6J genetic backgrounds. Atherosclerosis 2011; 220:78-85. [PMID: 22078246 DOI: 10.1016/j.atherosclerosis.2011.10.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 10/09/2011] [Accepted: 10/15/2011] [Indexed: 01/08/2023]
Abstract
OBJECTIVE We investigated the relationships between hemodynamics and differential plaque development at the aortic arch of apolipoprotein E (apoE)-null mice on 129S6/SvEvTac (129) and C57BL/6J (B6) genetic backgrounds. METHODS Mean flow velocities at the ascending and descending aorta (mVAA and mVDA) were measured by Doppler ultrasound in wild type and apoE-null male mice at 3 and 9 months of age. Following dissection of the aortic arches, anatomical parameters and plaque areas were evaluated. RESULTS Arch plaques were five times bigger in 129-apoE than in B6-apoE mice at 3 months, and twice as large at 9 months. The geometric differences, namely larger vessel diameter in the B6 strain and broader inner curvature of the aortic arch in the 129 strain, were exaggerated in 9-month-old apoE-null mice. Cardiac output and heart rate under anesthesia were significantly higher in the B6 strain than in the 129 strain. The values of mVAA were similar in the two strains, while mVDA was lower in the 129 strain. However, there was a 129-apoE-specific reduction of flow velocities with age, and both mVAA and mVDA were significantly lower in 129-apoE than in B6-apoE mice at 9 months. The mean relative wall shear stress (rWSS) over the aortic arch in 129-apoE and B6-apoE mice were not different, but animals with lower mean rWSS had larger arch plaques within each strain. CONCLUSIONS The plaque formation in the arch of apoE-null mice is accompanied by strain-dependent changes in both arch geometry and hemodynamics. While arch plaque sizes negatively correlate with mean rWSS, additional factors are necessary to account for the strain differences in arch plaque development.
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Affiliation(s)
- Hirofumi Tomita
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, CB #7525, 701 Brinkhous-Bullitt Building, Chapel Hill, NC 27599-7525, USA
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Ram R, Mickelsen DM, Theodoropoulos C, Blaxall BC. New approaches in small animal echocardiography: imaging the sounds of silence. Am J Physiol Heart Circ Physiol 2011; 301:H1765-80. [PMID: 21873501 DOI: 10.1152/ajpheart.00559.2011] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Systolic and diastolic dysfunction of the left ventricle (LV) is a hallmark of most cardiac diseases. In vivo assessment of heart function in animal models, particularly mice, is essential to refining our understanding of cardiovascular disease processes. Ultrasound echocardiography has emerged as a powerful, noninvasive tool to serially monitor cardiac performance and map the progression of heart dysfunction in murine injury models. This review covers current applications of small animal echocardiography, as well as emerging technologies that improve evaluation of LV function. In particular, we describe speckle-tracking imaging-based regional LV analysis, a recent advancement in murine echocardiography with proven clinical utility. This sensitive measure enables an early detection of subtle myocardial defects before global dysfunction in genetically engineered and rodent surgical injury models. Novel visualization technologies that allow in-depth phenotypic assessment of small animal models, including perfusion imaging and fetal echocardiography, are also discussed. As imaging capabilities continue to improve, murine echocardiography will remain a critical component of the investigator's armamentarium in translating animal data to enhanced clinical treatment of cardiovascular diseases.
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Affiliation(s)
- Rashmi Ram
- Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
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Iroquois homeobox gene 3 establishes fast conduction in the cardiac His-Purkinje network. Proc Natl Acad Sci U S A 2011; 108:13576-81. [PMID: 21825130 DOI: 10.1073/pnas.1106911108] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rapid electrical conduction in the His-Purkinje system tightly controls spatiotemporal activation of the ventricles. Although recent work has shed much light on the regulation of early specification and morphogenesis of the His-Purkinje system, less is known about how transcriptional regulation establishes impulse conduction properties of the constituent cells. Here we show that Iroquois homeobox gene 3 (Irx3) is critical for efficient conduction in this specialized tissue by antithetically regulating two gap junction-forming connexins (Cxs). Loss of Irx3 resulted in disruption of the rapid coordinated spread of ventricular excitation, reduced levels of Cx40, and ectopic Cx43 expression in the proximal bundle branches. Irx3 directly represses Cx43 transcription and indirectly activates Cx40 transcription. Our results reveal a critical role for Irx3 in the precise regulation of intercellular gap junction coupling and impulse propagation in the heart.
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Sider KL, Blaser MC, Simmons CA. Animal models of calcific aortic valve disease. Int J Inflam 2011; 2011:364310. [PMID: 21826258 PMCID: PMC3150155 DOI: 10.4061/2011/364310] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 04/27/2011] [Indexed: 11/20/2022] Open
Abstract
Calcific aortic valve disease (CAVD), once thought to be a degenerative disease, is now recognized to be an active pathobiological process, with chronic inflammation emerging as a predominant, and possibly driving, factor. However, many details of the pathobiological mechanisms of CAVD remain to be described, and new approaches to treat CAVD need to be identified. Animal models are emerging as vital tools to this end, facilitated by the advent of new models and improved understanding of the utility of existing models. In this paper, we summarize and critically appraise current small and large animal models of CAVD, discuss the utility of animal models for priority CAVD research areas, and provide recommendations for future animal model studies of CAVD.
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Affiliation(s)
- Krista L Sider
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, Canada M5S 3G9
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van Raaij ME, Lindvere L, Dorr A, He J, Sahota B, Foster FS, Stefanovic B. Functional micro-ultrasound imaging of rodent cerebral hemodynamics. Neuroimage 2011; 58:100-8. [PMID: 21704715 DOI: 10.1016/j.neuroimage.2011.05.088] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 04/11/2011] [Accepted: 05/23/2011] [Indexed: 11/16/2022] Open
Abstract
Healthy cerebral microcirculation is crucial to neuronal functioning. We present a new method to investigate microvascular hemodynamics in living rodent brain through a focal cranial window based on high-frequency ultrasound imaging. The method has a temporal resolution of 40ms, and a 100μm in-plane and 600μm through-plane spatial resolution. We use a commercially available high-frequency ultrasound imaging system to quantify changes in the relative cerebral blood volume (CBV) by measuring the scattered signal intensity from an ultrasound contrast agent circulating in the vasculature. Generalized linear model analysis is then used to produce effect size and significance maps of changes in cerebral blood volume upon electrical stimulation of the forepaw. We observe larger CBV increases in the forelimb representation of the primary somatosensory cortex than in the deep gray matter with stimuli as short as 2s (5.1 ± 1.3% vs. 3.3 ± 0.6%). We also investigate the temporal evolution of the blood volume changes in cortical and subcortical gray matter, pial vessels and subcortical major vessels, and show shorter response onset times in the parenchymal regions than in the neighboring large vessels (1.6 ± 1.0s vs. 2.6 ± 1.3s in the cortex for a 10 second stimulus protocol). This method, which we termed functional micro-ultrasound imaging or fMUS, is a novel, highly accessible, and cost-effective way of imaging rodent brain microvascular topology and hemodynamics in vivo at 100micron resolution over a 1-by-1cm field of view with 10s-100s frames per second that opens up a new set of questions regarding brain function in preclinical models of health and disease.
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Affiliation(s)
- Martijn E van Raaij
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
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