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Gao S, Liu XP, Li TT, Chen L, Feng YP, Wang YK, Yin YJ, Little PJ, Wu XQ, Xu SW, Jiang XD. Animal models of heart failure with preserved ejection fraction (HFpEF): from metabolic pathobiology to drug discovery. Acta Pharmacol Sin 2024; 45:23-35. [PMID: 37644131 PMCID: PMC10770177 DOI: 10.1038/s41401-023-01152-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023] Open
Abstract
Heart failure (HF) with preserved ejection fraction (HFpEF) is currently a preeminent challenge for cardiovascular medicine. It has a poor prognosis, increasing mortality, and is escalating in prevalence worldwide. Despite accounting for over 50% of all HF patients, the mechanistic underpinnings driving HFpEF are poorly understood, thus impeding the discovery and development of mechanism-based therapies. HFpEF is a disease syndrome driven by diverse comorbidities, including hypertension, diabetes and obesity, pulmonary hypertension, aging, and atrial fibrillation. There is a lack of high-fidelity animal models that faithfully recapitulate the HFpEF phenotype, owing primarily to the disease heterogeneity, which has hampered our understanding of the complex pathophysiology of HFpEF. This review provides an updated overview of the currently available animal models of HFpEF and discusses their characteristics from the perspective of energy metabolism. Interventional strategies for efficiently utilizing energy substrates in preclinical HFpEF models are also discussed.
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Affiliation(s)
- Si Gao
- Department of Pharmacy, School of Medicine, Guangxi University of Science and Technology, Liuzhou, 545005, China
| | - Xue-Ping Liu
- Department of Pharmacy, School of Medicine, Guangxi University of Science and Technology, Liuzhou, 545005, China
| | - Ting-Ting Li
- Department of Pharmacy, School of Medicine, Guangxi University of Science and Technology, Liuzhou, 545005, China
| | - Li Chen
- Department of Pharmacy, School of Medicine, Guangxi University of Science and Technology, Liuzhou, 545005, China
| | - Yi-Ping Feng
- Department of Pharmacy, School of Medicine, Guangxi University of Science and Technology, Liuzhou, 545005, China
| | - Yu-Kun Wang
- Department of Pharmacy, School of Medicine, Guangxi University of Science and Technology, Liuzhou, 545005, China
| | - Yan-Jun Yin
- School of Pharmacy, Bengbu Medical College, Bengbu, 233000, China
| | - Peter J Little
- School of Pharmacy, University of Queensland, Pharmacy Australia Centre of Excellence, Woolloongabba, QLD, 4102, Australia
| | - Xiao-Qian Wu
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, the NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China.
| | - Suo-Wen Xu
- Department of Endocrinology, First Affiliated Hospital, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China.
| | - Xu-Dong Jiang
- Department of Pharmacy, School of Medicine, Guangxi University of Science and Technology, Liuzhou, 545005, China.
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Polak-Iwaniuk A, Harasim-Symbor E, Gołaszewska K, Chabowski A. How Hypertension Affects Heart Metabolism. Front Physiol 2019; 10:435. [PMID: 31040794 PMCID: PMC6476990 DOI: 10.3389/fphys.2019.00435] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/29/2019] [Indexed: 01/15/2023] Open
Abstract
Hypertension is one of the most frequently observed cardiovascular diseases, which precedes heart failure in 75% of its cases. It is well-established that hypertensive patients have whole body metabolic complications such as hyperlipidemia, hyperglycemia, decreased insulin sensitivity or diabetes mellitus. Since myocardial metabolism is strictly dependent on hormonal status as well as substrate milieu, the above mentioned disturbances may affect energy generation status in the heart. Interestingly, it was found that hypertension induces a shift in substrate preference toward increased glucose utilization in cardiac muscle, prior to structural changes development. The present work reports advances in the aspect of heart metabolism under high blood pressure conditions, including human and the most common animal models of hypertension.
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Affiliation(s)
| | - Ewa Harasim-Symbor
- Department of Physiology, Medical University of Białystok, Białystok, Poland
| | | | - Adrian Chabowski
- Department of Physiology, Medical University of Białystok, Białystok, Poland
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Huber JS, Hernandez AM, Janabi M, O'Neil JP, Brennan KM, Murphy ST, Seo Y, Gullberg GT. Longitudinal Evaluation of Myocardial Fatty Acid and Glucose Metabolism in Fasted and Nonfasted Spontaneously Hypertensive Rats Using MicroPET/CT. Mol Imaging 2018; 16:1536012117724558. [PMID: 28877656 PMCID: PMC5593226 DOI: 10.1177/1536012117724558] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Using longitudinal micro positron emission tomography (microPET)/computed tomography (CT) studies, we quantified changes in myocardial metabolism and perfusion in spontaneously hypertensive rats (SHRs), a model of left ventricular hypertrophy (LVH). Fatty acid and glucose metabolism were quantified in the hearts of SHRs and Wistar-Kyoto (WKY) normotensive rats using long-chain fatty acid analog 18F-fluoro-6-thia heptadecanoic acid (18F-FTHA) and glucose analog 18F-fluorodeoxyglucose (18F-FDG) under normal or fasting conditions. We also used 18F-fluorodihydrorotenol (18F-FDHROL) to investigate perfusion in their hearts without fasting. Rats were imaged at 4 or 5 times over their life cycle. Compartment modeling was used to estimate the rate constants for the radiotracers. Blood samples were obtained and analyzed for glucose and free fatty acid concentrations. SHRs demonstrated no significant difference in 18F-FDHROL wash-in rate constant (P = .1) and distribution volume (P = .1), significantly higher 18F-FDG myocardial influx rate constant (P = 4×10−8), and significantly lower 18F-FTHA myocardial influx rate constant (P = .007) than WKYs during the 2009-2010 study without fasting. SHRs demonstrated a significantly higher 18F-FDHROL wash-in rate constant (P = 5×10−6) and distribution volume (P = 3×10−8), significantly higher 18F-FDG myocardial influx rate constant (P = 3×10−8), and a higher trend of 18F-FTHA myocardial influx rate constant (not significant, P = .1) than WKYs during the 2011–2012 study with fasting. Changes in glucose plasma concentrations were generally negatively correlated with corresponding radiotracer influx rate constant changes. The study indicates a switch from preferred fatty acid metabolism to increased glucose metabolism with hypertrophy. Increased perfusion during the 2011-2012 study may be indicative of increased aerobic metabolism in the SHR model of LVH.
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Affiliation(s)
- Jennifer S Huber
- 1 Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Andrew M Hernandez
- 2 Department of Radiology, University of California Davis, Sacramento, CA, USA
| | - Mustafa Janabi
- 1 Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James P O'Neil
- 1 Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kathleen M Brennan
- 1 Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Stephanie T Murphy
- 3 Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Youngho Seo
- 1 Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,3 Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA.,4 Department of Radiation Oncology, University of California, San Francisco, CA, USA.,5 UC Berkeley-UCSF Graduate Program in Bioengineering, Berkeley and San Francisco, CA, USA
| | - Grant T Gullberg
- 1 Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,3 Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA.,5 UC Berkeley-UCSF Graduate Program in Bioengineering, Berkeley and San Francisco, CA, USA
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Quintana-Villamandos B, Gomez de Diego JJ, Delgado-Martos MJ, Muñoz-Valverde D, Soto-Montenegro ML, Desco M, Delgado-Baeza E. Dronedarone produces early regression of myocardial remodelling in structural heart disease. PLoS One 2017; 12:e0188442. [PMID: 29161309 PMCID: PMC5697839 DOI: 10.1371/journal.pone.0188442] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 11/07/2017] [Indexed: 01/13/2023] Open
Abstract
Background and aims Left ventricular hypertrophy (LVH) in hypertension is associated with a greater risk of sustained supraventricular/atrial arrhythmias. Dronedarone is an antiarrhythmic agent that was recently approved for the treatment of atrial fibrillation. However, its effect on early regression of LVH has not been reported. We tested the hypothesis that short-term administration of dronedarone induces early regression of LVH in spontaneously hypertensive rats (SHRs). Methods Ten-month-old male SHRs were randomly assigned to an intervention group (SHR-D), where animals received dronedarone treatment (100 mg/kg) for a period of 14 days, or to a control group (SHR) where rats were given vehicle. A third group with normotensive control rats (WKY) was also added. At the end of the treatment with dronedarone we studied the cardiac anatomy and function in all the rats using transthoracic echocardiogram, cardiac metabolism using the PET/CT study (2-deoxy-2[18F]fluoro-D-glucose) and cardiac structure by histological analysis of myocyte size and collagen content. Results The hypertensive vehicle treated SHR rats developed the classic cardiac pattern of hypertensive cardiomyopathy as expected for the experimental model, with increases in left ventricular wall thickness, a metabolic shift towards an increase in glucose use and increases in myocyte and collagen content. However, the SHR-D rats showed statistically significant lower values in comparison to SHR group for septal wall thickness, posterior wall thickness, ventricular mass, glucose myocardial uptake, size of left ventricular cardiomyocytes and collagen content. All these values obtained in SHR-D rats were similar to the values measured in the normotensive WKY control group. Conclusion The results suggest by three alternative and complementary ways (analysis of anatomy and cardiac function, metabolism and histological structure) that dronedarone has the potential to reverse the LVH induced by arterial hypertension in the SHR model of compensated ventricular hypertrophy.
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Affiliation(s)
- Begoña Quintana-Villamandos
- Departamento de Anestesiología, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Departamento de Farmacología, Facultad Medicina, Universidad Complutense de Madrid, Spain.,Departamento de Medicina y Cirugía Experimental, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Jose Juan Gomez de Diego
- Departamento de Medicina y Cirugía Experimental, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.,Departamento de Cardiología, Hospital Clínico San Carlos, Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - María Jesús Delgado-Martos
- Departamento de Medicina y Cirugía Experimental, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - David Muñoz-Valverde
- Departamento de Cirugía Experimental, Facultad Medicina, Universidad Autónoma de Madrid, Spain
| | - María Luisa Soto-Montenegro
- Departamento de Medicina y Cirugía Experimental, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Manuel Desco
- Departamento de Medicina y Cirugía Experimental, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.,Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
| | - Emilio Delgado-Baeza
- Departamento de Medicina y Cirugía Experimental, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
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Zan Y, Long Y, Chen K, Li B, Huang Q, Gullberg GT. Design of a short nonuniform acquisition protocol for quantitative analysis in dynamic cardiac SPECT imaging - a retrospective123I-MIBG animal study. Med Phys 2017; 44:3639-3649. [DOI: 10.1002/mp.12288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 12/25/2022] Open
Affiliation(s)
- Yunlong Zan
- School of Biomedical Engineering; Shanghai Jiao Tong University; Shanghai China
- School of Medicine; Department of Nuclear Medicine; Rui Jin Hospital; Shanghai Jiao Tong University; Shanghai China
- University of Michigan - Shanghai Jiao Tong University Joint Institute; Shanghai Jiao Tong University; Shanghai China
| | - Yong Long
- University of Michigan - Shanghai Jiao Tong University Joint Institute; Shanghai Jiao Tong University; Shanghai China
| | - Kewei Chen
- Image Analysis and Research Lab.; Banner Good Samaritan Medical Center; Phoenix AZ USA
| | - Biao Li
- School of Medicine; Department of Nuclear Medicine; Rui Jin Hospital; Shanghai Jiao Tong University; Shanghai China
| | - Qiu Huang
- School of Biomedical Engineering; Shanghai Jiao Tong University; Shanghai China
- School of Medicine; Department of Nuclear Medicine; Rui Jin Hospital; Shanghai Jiao Tong University; Shanghai China
| | - Grant T. Gullberg
- Life Science Division; Lawrence Berkeley National Laboratory; Berkeley CA USA
- Radiology and Biomedical Imaging; University of California; San Francisco CA USA
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Kobayashi M, Matsunari I, Nishi K, Mizutani A, Miyazaki Y, Ogai K, Sugama J, Shiba K, Kawai K, Kinuya S. Simultaneous acquisition of (99m)Tc- and (123)I-labeled radiotracers using a preclinical SPECT scanner with CZT detectors. Ann Nucl Med 2016; 30:263-71. [PMID: 26747655 DOI: 10.1007/s12149-015-1055-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/23/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Simultaneous acquisition of (99m)Tc and (123)I was evaluated using a preclinical SPECT scanner with cadmium zinc telluride (CZT)-based detectors. METHODS 10-ml cylindrical syringes contained about 37 MBq (99m)Tc-tetrofosmin ((99m)Tc-TF) or 37 MBq (123)I-15-(p-iodophenyl)-3R,S-methyl pentadecanoic acid ((123)I-BMIPP) were used to assess the relationship between these SPECT radioactive counts and radioactivity. Two 10-ml syringes contained 100 or 300 MBq (99m)Tc-TF and 100 MBq (123)I-BMIPP to assess the influence of (99m)Tc upscatter and (123)I downscatter, respectively. A rat-sized cylindrical phantom also contained both 100 or 300 MBq (99m)Tc-TF and 100 MBq (123)I-BMIPP. The two 10-ml syringes and phantom were scanned using a pinhole collimator for rats. Myocardial infarction model rats were examined using 300 MBq (99m)Tc-TF and 100 MBq (123)I-BMIPP. Two 1-ml syringes contained 105 MBq (99m)Tc-labeled hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) and 35 MBq (123)I-labeled N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane ((123)I-FP-CIT). The two 1-ml syringes were scanned using a pinhole collimator for mice. Normal mice were examined using 105 MBq (99m)Tc-HMPAO and 35 MBq (123)I-FP-CIT. RESULTS The relationship between SPECT radioactive counts and radioactivity was excellent. Downscatter contamination of (123)I-BMIPP exhibited fewer radioactive counts for 300 MBq (99m)Tc-TF without scatter correction (SC) in 125-150 keV. There was no upscatter contamination of (99m)Tc-TF in 150-175 keV. In the rat-sized phantom, the radioactive count ratio decreased to 4.0 % for 300 MBq (99m)Tc-TF without SC in 125-150 keV. In the rats, myocardial images and radioactive counts of (99m)Tc-TF with the dual tracer were identical to those of the (99m)Tc-TF single injection. Downscatter contamination of (123)I-FP-CIT was 4.2 % without SC in 125-150 keV. In the first injection of (99m)Tc-HMPAO and second injection of (123)I-FP-CIT, brain images and radioactive counts of (99m)Tc-HMPAO with the dual tracer in normal mice also were the similar to those of the (99m)Tc-HMPAO single injection. In the first injection of (123)I-FP-CIT and second injection of (99m)Tc-HMPAO, the brain images and radioactive counts with the dual tracer were not much different from those of the (123)I-FP-CIT single injection. CONCLUSIONS Dual-tracer imaging of (99m)Tc- and (123)I-labeled radiotracers is feasible in a preclinical SPECT scanner with CZT detector. When higher radioactivity of (99m)Tc-labeled radiotracers relative to (123)I-labeled radiotracers is applied, correction methods are not necessarily required for the quantification of (99m)Tc- and (123)I-labeled radiotracers when using a preclinical SPECT scanner with CZT detector.
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Affiliation(s)
- Masato Kobayashi
- Wellness Promotion Science Center, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942, Japan.
| | - Ichiro Matsunari
- Clinical Research Department, The Medical and Pharmacological Research Center Foundation, Hakui, Japan
- Division of Nuclear Medicine, Department of Radiology, Saitama Medical University Hospital, Saitama, Japan
| | - Kodai Nishi
- Department of Radioisotope Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Asuka Mizutani
- Graduate School of Medicine, Division of Health Sciences, Osaka University, Osaka, Japan
| | - Yoshiharu Miyazaki
- Clinical Research Department, The Medical and Pharmacological Research Center Foundation, Hakui, Japan
| | - Kazuhiro Ogai
- Wellness Promotion Science Center, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942, Japan
| | - Jyunko Sugama
- Wellness Promotion Science Center, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942, Japan
| | - Kazuhiro Shiba
- Division of Tracer Kinetics, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
| | - Keiichi Kawai
- School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Seigo Kinuya
- School of Medical Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
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Zan Y, Boutchko R, Huang Q, Li B, Chen K, Gullberg GT. Fast direct estimation of the blood input function and myocardial time activity curve from dynamic SPECT projections via reduction in spatial and temporal dimensions. Med Phys 2014; 40:092503. [PMID: 24007179 DOI: 10.1118/1.4816944] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Reconstruction of parametric images from dynamic single photon emission computed tomography (SPECT) data acquired with slow rotating cameras is a challenge because the estimation of the time-activity curves (TACs) may involve fitting data to an inconsistent underdetermined system of equations. This work presents a novel algorithm for the estimation of the blood input function and myocardial TAC with high accuracy and high efficiency directly from these projections. METHODS In the proposed dynamic reconstruction method, the information from the segmentation of functional regions from the static reconstructed image was used as a prior to construct a sparse matrix, through which the spatial distribution of the radioactive tracer was represented. Then the temporal distribution of the radioactive tracer was modeled by nonuniform B-spline basis functions which were determined according to a new selection rule. With reduction in both the spatial and temporal dimensions of the reconstructed image, the blood input function and myocardial TAC were estimated using the 4D maximum likelihood expectation maximization algorithm. The method was validated using data from both digital phantom simulations and an experimental rat study. RESULTS Compared with the conventional dynamic SPECT reconstruction method without the reduction in spatial dimensions, the proposed method provides more accurate TACs with less computation time in both phantom simulation studies and a rat experimental study. CONCLUSIONS The proposed method is promising in both providing more accurate time-activity curves and reducing the computation time, which makes it practical for small animal studies using clinical systems with slow rotating cameras.
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Affiliation(s)
- Yunlong Zan
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China and Rui Jin Hospital, School of medicine, Shanghai Jiao Tong University, Shanghai 200030, China
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Hernandez AM, Huber JS, Murphy ST, Janabi M, Zeng GL, Brennan KM, O'Neil JP, Seo Y, Gullberg GT. Longitudinal evaluation of left ventricular substrate metabolism, perfusion, and dysfunction in the spontaneously hypertensive rat model of hypertrophy using small-animal PET/CT imaging. J Nucl Med 2013; 54:1938-45. [PMID: 24092939 DOI: 10.2967/jnumed.113.120105] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Myocardial metabolic and perfusion imaging is a vital tool for understanding the physiologic consequences of heart failure. We used PET imaging to examine the longitudinal kinetics of (18)F-FDG and 14(R,S)-(18)F-fluoro-6-thia-heptadecanoic acid ((18)F-FTHA) as analogs of glucose and fatty acid (FA) to quantify metabolic substrate shifts with the spontaneously hypertensive rat (SHR) as a model of left ventricular hypertrophy (LVH) and failure. Myocardial perfusion and left ventricular function were also investigated using a newly developed radiotracer (18)F-fluorodihydrorotenol ((18)F-FDHROL). METHODS Longitudinal dynamic electrocardiogram-gated small-animal PET/CT studies were performed with 8 SHR and 8 normotensive Wistar-Kyoto (WKY) rats over their life cycle. We determined the myocardial influx rate constant for (18)F-FDG and (18)F-FTHA (Ki(FDG) and Ki(FTHA), respectively) and the wash-in rate constant for (18)F-FDHROL (K1(FDHROL)). (18)F-FDHROL data were also used to quantify left ventricular ejection fraction (LVEF) and end-diastolic volume (EDV). Blood samples were drawn to independently measure plasma concentrations of glucose, insulin, and free fatty acids (FFAs). RESULTS Ki(FDG) and Ki(FTHA) were higher in SHRs than WKY rats (P < 3 × 10(-8) and 0.005, respectively) independent of age. A decrease in Ki(FDG) with age was evident when models were combined (P = 0.034). The SHR exhibited higher K1(FDHROL) (P < 5 × 10(-6)) than the control, with no age-dependent trends in either model (P = 0.058). Glucose plasma concentrations were lower in SHRs than controls (P < 6 × 10(-12)), with an age-dependent rise for WKY rats (P < 2 × 10(-5)). Insulin plasma concentrations were higher in SHRs than controls (P < 3 × 10(-3)), with an age-dependent decrease when models were combined (P = 0.046). FFA levels were similar between models (P = 0.374), but an increase with age was evident only in SHR (P < 7 × 10(-6)). CONCLUSION The SHR exhibited alterations in myocardial substrate use at 8 mo characterized by increased glucose and FA utilizations. At 20 mo, the SHR had LVH characterized by decreased LVEF and increased EDV, while simultaneously sustaining higher glucose and similar FA utilizations (compared with WKY rats), which indicates maladaptation of energy substrates in the failing heart. Elevated K1(FDHROL) in the SHR may reflect elevated oxygen consumption and decreased capillary density in the hypertrophied heart. From our findings, metabolic changes appear to precede mechanical changes of LVH progression in the SHR model.
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Affiliation(s)
- Andrew M Hernandez
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
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Boutchko R, Sitek A, Gullberg GT. Practical implementation of tetrahedral mesh reconstruction in emission tomography. Phys Med Biol 2013; 58:3001-22. [PMID: 23588373 DOI: 10.1088/0031-9155/58/9/3001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This paper presents a practical implementation of image reconstruction on tetrahedral meshes optimized for emission computed tomography with parallel beam geometry. Tetrahedral mesh built on a point cloud is a convenient image representation method, intrinsically three-dimensional and with a multi-level resolution property. Image intensities are defined at the mesh nodes and linearly interpolated inside each tetrahedron. For the given mesh geometry, the intensities can be computed directly from tomographic projections using iterative reconstruction algorithms with a system matrix calculated using an exact analytical formula. The mesh geometry is optimized for a specific patient using a two stage process. First, a noisy image is reconstructed on a finely-spaced uniform cloud. Then, the geometry of the representation is adaptively transformed through boundary-preserving node motion and elimination. Nodes are removed in constant intensity regions, merged along the boundaries, and moved in the direction of the mean local intensity gradient in order to provide higher node density in the boundary regions. Attenuation correction and detector geometric response are included in the system matrix. Once the mesh geometry is optimized, it is used to generate the final system matrix for ML-EM reconstruction of node intensities and for visualization of the reconstructed images. In dynamic PET or SPECT imaging, the system matrix generation procedure is performed using a quasi-static sinogram, generated by summing projection data from multiple time frames. This system matrix is then used to reconstruct the individual time frame projections. Performance of the new method is evaluated by reconstructing simulated projections of the NCAT phantom and the method is then applied to dynamic SPECT phantom and patient studies and to a dynamic microPET rat study. Tetrahedral mesh-based images are compared to the standard voxel-based reconstruction for both high and low signal-to-noise ratio projection datasets. The results demonstrate that the reconstructed images represented as tetrahedral meshes based on point clouds offer image quality comparable to that achievable using a standard voxel grid while allowing substantial reduction in the number of unknown intensities to be reconstructed and reducing the noise.
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Affiliation(s)
- R Boutchko
- Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS 55R0121, Berkeley, CA 94720, USA.
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Amoozegar CB, Wang T, Bouchard MB, McCaslin AFH, Blaner WS, Levenson RM, Hillman EMC. Dynamic contrast-enhanced optical imaging of in vivo organ function. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:96003-1. [PMID: 23085904 PMCID: PMC3434471 DOI: 10.1117/1.jbo.17.9.096003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Conventional approaches to optical small animal molecular imaging suffer from poor resolution, limited sensitivity, and unreliable quantitation, often reducing their utility in practice. We previously demonstrated that the in vivo dynamics of an injected contrast agent could be exploited to provide high-contrast anatomical registration, owing to the temporal differences in each organ's response to the circulating fluorophore. This study extends this approach to explore whether dynamic contrast-enhanced optical imaging (DyCE) can allow noninvasive, in vivo assessment of organ function by quantifying the differing cellular uptake or wash-out dynamics of an agent in healthy and damaged organs. Specifically, we used DyCE to visualize and measure the organ-specific uptake dynamics of indocyanine green before and after induction of transient liver damage. DyCE imaging was performed longitudinally over nine days, and blood samples collected at each imaging session were analyzed for alanine aminotransferase (ALT), a liver enzyme assessed clinically as a measure of liver damage. We show that changes in DyCE-derived dynamics of liver and kidney dye uptake caused by liver damage correlate linearly with ALT concentrations, with an r2 value of 0.91. Our results demonstrate that DyCE can provide quantitative, in vivo, longitudinal measures of organ function with inexpensive and simple data acquisition.
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Affiliation(s)
- Cyrus B Amoozegar
- Columbia University, Department of Biomedical Engineering and Radiology, Laboratory for Functional Optical Imaging, 351 Engineering Terrace, 1210 Amsterdam Avenue, New York, New York 10027, USA.
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