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Wang H, Fan L, Choy JS, Kassab GS, Lee LC. Mechanisms of coronary sinus reducer for treatment of myocardial ischemia: in silico study. J Appl Physiol (1985) 2024; 136:1157-1169. [PMID: 38511210 DOI: 10.1152/japplphysiol.00910.2023] [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: 12/20/2023] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 03/22/2024] Open
Abstract
The coronary sinus reducer (CSR) is an emerging medical device for treating patients with refractory angina, often associated with myocardial ischemia. Patients implanted with CSR have shown positive outcomes, but the underlying mechanisms are unclear. This study sought to understand the mechanisms of CSR by investigating its effects on coronary microcirculation hemodynamics that may help explain the therapy's efficacy. We applied a validated computer model of the coronary microcirculation to investigate how CSR affects hemodynamics under different degrees of coronary artery stenosis. With moderate coronary stenosis, an increase in capillary transit time (CTT) [up to 69% with near-complete coronary sinus (CS) occlusion] is the key change associated with CSR. Because capillaries in the microcirculation can still receive oxygenated blood from the upstream artery with moderate stenosis, the increase in CTT allows more time for the exchange of gases and nutrients, aiding tissue oxygenation. With severe coronary stenosis; however, the redistribution of blood draining from the nonischemic region to the ischemic region (up to 96% with near-complete CS occlusion) and the reduction in capillary flow heterogeneity are the key changes associated with CSR. Because blood draining from the nonischemic region is not completely devoid of O2, the redistribution of blood to the capillaries in the ischemic region by CSR is beneficial especially when little or no oxygenated blood reaches these capillaries. This simulation study provides insights into the mechanisms of CSR in improving clinical symptoms. The mechanisms differ with the severity of the upstream stenosis.NEW & NOTEWORTHY Emerging coronary venous retroperfusion treatments, particularly coronary sinus reducer (CSR) for refractory angina linked to myocardial ischemia, show promise; however, their mechanisms of action are not well understood. We find that CSR's effectiveness varies with the severity of coronary stenosis. In moderate stenosis, CSR improves tissue oxygenation by increasing capillary transit time, whereas in severe stenosis, it redistributes blood from nonischemic to ischemic regions and reduces capillary flow heterogeneity.
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Affiliation(s)
- Haifeng Wang
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, United States
| | - Lei Fan
- Joint Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Jenny S Choy
- California Medical Innovations Institute, San Diego, California, United States
| | - Ghassan S Kassab
- California Medical Innovations Institute, San Diego, California, United States
| | - Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, United States
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Wang H, Fan L, Choy JS, Kassab GS, Lee LC. Simulation of coronary capillary transit time based on full vascular model of the heart. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 243:107908. [PMID: 37931581 PMCID: PMC10872892 DOI: 10.1016/j.cmpb.2023.107908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/24/2023] [Accepted: 10/30/2023] [Indexed: 11/08/2023]
Abstract
Capillary transit time (CTT) is a fundamental determinant of gas exchange between blood and tissues in the heart and other organs. Despite advances in experimental techniques, it remains difficult to measure coronary CTT in vivo. Here, we developed a novel computational framework that couples coronary microcirculation with cardiac mechanics in a closed-loop system that enables prediction of hemodynamics in the entire coronary network, including arteries, veins, and capillaries. We also developed a novel "particle-tracking" approach for computing CTT where "virtual tracers" are individually tracked as they traverse the capillary network. Model predictions compare well with blood pressure and flow rate distributions in the arterial network reported in previous studies. Model predictions of transit times in the capillaries (1.21 ± 1.5 s) and entire coronary network (11.8 ± 1.8 s) also agree with measurements. We show that, with increasing coronary artery stenosis (as quantified by fractional flow reserve, FFR), intravascular pressure and flow rate downstream are reduced but remain non-stationary even at 100 % stenosis because some flow (∼3 %) is redistributed from the non-occluded to the occluded territories. Importantly, the model predicts that occlusion of a large artery results in higher CTT. For moderate stenosis (FFR > 0.6), the increase in CTT (from 1.21 s without stenosis to 2.23 s at FFR=0.6) is caused by a decrease in capillary flow rate. In severe stenosis (FFR = 0.1), the increase in CTT to 14.2 s is due to both a decrease in flow rate and an increase in path length taken by "virtual tracers" in the capillary network.
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Affiliation(s)
- Haifeng Wang
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA.
| | - Lei Fan
- The Joint Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jenny S Choy
- California Medical Innovations Institute, San Diego, California, USA
| | - Ghassan S Kassab
- California Medical Innovations Institute, San Diego, California, USA
| | - Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
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3
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Guo T, Zheng R, Yi H, Yang Y. Association between initial microcirculation disturbance patients and mortality in patients who are critically ill: A retrospective cohort study. Medicine (Baltimore) 2023; 102:e35500. [PMID: 37904383 PMCID: PMC10615475 DOI: 10.1097/md.0000000000035500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 09/14/2023] [Indexed: 11/01/2023] Open
Abstract
Impact of microcirculation status from mortality of critically ill population has been investigated for decades, but the prognosis of early initial microcirculation disturbance in critically ill population in the intensive care unit remains to be explored. The cohort study was conducted using the medical information database for intensive care IV. Critically ill adult in intensive care unit have been enrolled and categorized by early microcirculation status. Cox Proportional-Hazards models have been utilized for testing intermediaries and assess the relationship between combined early initial microcirculation disturbance and mortality. Several 2286 patients were initially screened. Some patients with a highest lactate level >2.2 mmol/L on the firstly day of admission (n = 1468) were then extracted for further analysis. 735 patients received in the initial microcirculation disturbance group as well as 733 patients were in the hyperlactatemia group. In those with elevated lactate, the 28-day mortality of early microcirculation disturbance was higher than that of hyperlactatemia alone (7-day mortality [16.19% vs 12.68%; Adjusted hazard ratio 1.35, 95% confidence intervals 1.03 to 1.78, P = .029], 28-day mortality [33.33% vs 27.28%; adjusted HR 1.34, 95% confidence interval 1.11 to 1.67, P = .002]). Early microcirculatory disturbances (increased PV-ACO2/CA-VO2 ratio and higher initial blood lactate level) were more reliable predictors of in-hospital mortality than early isolated lactate elevation.
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Affiliation(s)
- Tongwu Guo
- Emergency and Trauma College, Hainan Medical University, Haikou, China
| | - Rui Zheng
- Emergency and Trauma College, Hainan Medical University, Haikou, China
| | - Huanying Yi
- Brief introduction of International Nursing School, Hainan Medical University, Haikou, China
| | - Yuanzheng Yang
- Emergency and Trauma College, Hainan Medical University, Haikou, China
- The First Affiliated Hospital of Hainan Medical University, Haikou, China
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4
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Karst NJ, Geddes JB. Modeling transit time distributions in microvascular networks. J Theor Biol 2023; 572:111584. [PMID: 37482178 DOI: 10.1016/j.jtbi.2023.111584] [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: 03/08/2023] [Revised: 07/10/2023] [Accepted: 07/14/2023] [Indexed: 07/25/2023]
Abstract
The time a red blood cell (RBC) spends in the microvasculature is of prime importance for a number of physiological processes. In this work, we present a methodology for computing an approximation of the so-called transit time distribution (TTD), i.e., the probabilistic description of how long a RBC will reside within the network. As a proof of concept, we apply this methodology to three flavors of the mesh networks. We show that each network type supports multiple distinct steady-state configurations and we present tools for analyzing the associated collection of TTDs, ranging from standard measures like mean capillary transit time (MCTT) and capillary transit time heterogeneity (CTTH) to novel metrics.
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Affiliation(s)
| | - John B Geddes
- Olin College of Engineering, Needham, 02492, MA, USA
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Ndrepepa G, Kastrati A. Coronary No-Reflow after Primary Percutaneous Coronary Intervention-Current Knowledge on Pathophysiology, Diagnosis, Clinical Impact and Therapy. J Clin Med 2023; 12:5592. [PMID: 37685660 PMCID: PMC10488607 DOI: 10.3390/jcm12175592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/17/2023] [Accepted: 08/26/2023] [Indexed: 09/10/2023] Open
Abstract
Coronary no-reflow (CNR) is a frequent phenomenon that develops in patients with ST-segment elevation myocardial infarction (STEMI) following reperfusion therapy. CNR is highly dynamic, develops gradually (over hours) and persists for days to weeks after reperfusion. Microvascular obstruction (MVO) developing as a consequence of myocardial ischemia, distal embolization and reperfusion-related injury is the main pathophysiological mechanism of CNR. The frequency of CNR or MVO after primary PCI differs widely depending on the sensitivity of the tools used for diagnosis and timing of examination. Coronary angiography is readily available and most convenient to diagnose CNR but it is highly conservative and underestimates the true frequency of CNR. Cardiac magnetic resonance (CMR) imaging is the most sensitive method to diagnose MVO and CNR that provides information on the presence, localization and extent of MVO. CMR imaging detects intramyocardial hemorrhage and accurately estimates the infarct size. MVO and CNR markedly negate the benefits of reperfusion therapy and contribute to poor clinical outcomes including adverse remodeling of left ventricle, worsening or new congestive heart failure and reduced survival. Despite extensive research and the use of therapies that target almost all known pathophysiological mechanisms of CNR, no therapy has been found that prevents or reverses CNR and provides consistent clinical benefit in patients with STEMI undergoing reperfusion. Currently, the prevention or alleviation of MVO and CNR remain unmet goals in the therapy of STEMI that continue to be under intense research.
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Affiliation(s)
- Gjin Ndrepepa
- Deutsches Herzzentrum München, Technische Universität München, Lazarettstrasse 36, 80636 Munich, Germany;
| | - Adnan Kastrati
- Deutsches Herzzentrum München, Technische Universität München, Lazarettstrasse 36, 80636 Munich, Germany;
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, 80336 Munich, Germany
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Hyakutake T, Tsutsumi Y, Miyoshi Y, Yasui M, Mizuno T, Tateno M. Red Blood Cell Partitioning Using a Microfluidic Channel with Ladder Structure. MICROMACHINES 2023; 14:1421. [PMID: 37512732 PMCID: PMC10385109 DOI: 10.3390/mi14071421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023]
Abstract
This study investigated the partitioning characteristics of red blood cells (RBCs) within capillaries, with a specific focus on ladder structures observed near the end of the capillaries. In vitro experiments were conducted using microfluidic channels with a ladder structure model comprising six bifurcating channels that exhibited an anti-parallel flow configuration. The effects of various factors, such as the parent channel width, distance between branches, and hematocrit, on RBC partitioning in bifurcating channels were evaluated. A decrease in the parent channel width resulted in an increase in the heterogeneity in the hematocrit distribution and a bias in the fractional RBC flux. Additionally, variations in the distance between branches affected the RBC distribution, with smaller distances resulting in greater heterogeneity. The bias of the RBC distribution in the microchannel cross section had a major effect on the RBC partitioning characteristics. The influence of hematocrit variations on the RBC distribution was also investigated, with lower hematocrit values leading to a more pronounced bias in the RBC distribution. Overall, this study provides valuable insights into RBC distribution characteristics in capillary networks, contributing to our understanding of the physiological mechanisms of RBC phase separation in the microcirculatory system. These findings have implications for predicting oxygen heterogeneity in tissues and could aid in the study of diseases associated with impaired microcirculation.
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Affiliation(s)
- Toru Hyakutake
- Faculty of Engineering, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
| | - Yuya Tsutsumi
- Graduate School of Engineering Science, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
| | - Yohei Miyoshi
- Graduate School of Engineering Science, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
| | - Manabu Yasui
- Kanagawa Institute of Industrial Science and Technology, 705-1 Shimoimaizumi, Ebina 243-0435, Japan
| | - Tomoki Mizuno
- Graduate School of Engineering Science, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
| | - Mizuki Tateno
- College of Engineering Science, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
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Terman D. Modeling the response of homogeneous and heterogeneous cerebral capillary networks to local changes in vessel diameters. J Theor Biol 2023; 568:111509. [PMID: 37120132 DOI: 10.1016/j.jtbi.2023.111509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/01/2023]
Abstract
While microvascular cerebral capillary networks are known to be highly heterogeneous, previous computational models have predicted that heterogeneous cerebral capillary flow patterns result in lower brain tissue partial oxygen pressures. Moreover, as blood flow increases, the flux among capillaries homogenizes. This homogenization of flow is expected to improve the efficiency of oxygenation extraction from the blood. In this work, we use mathematical modeling to explore a possible functional role for the high degree of heterogeneity observed in cerebral capillary networks. Our results suggest that heterogeneity allows for a greater response of tissue oxygen levels to local changes in vessel diameters due to neuronal activation. This result is confirmed for a full 3-dimensional model of capillary networks that includes oxygen diffusion within the tissue region and a reduced model that accounts for changes in capillary blood flow.
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Affiliation(s)
- David Terman
- Department of Mathematics, The Ohio State University, Columbus, Ohio, 43210 USA.
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Shan H, Shi L, Liu S, Yuan Y, Li H, Chen S, Zhou X. A local-saturation-and-delay MRI method for evaluation of red blood cells aggregation in vivo for tumor-bearing or drug-used rats. Front Bioeng Biotechnol 2023; 11:1111840. [PMID: 36733963 PMCID: PMC9887193 DOI: 10.3389/fbioe.2023.1111840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/06/2023] [Indexed: 01/18/2023] Open
Abstract
Hyperviscosity syndrome (HVS) is a combination of clinical signs and symptoms related to increased blood viscosity. HVS can increase the thrombotic risk by causing a major disturbance to the blood flow, which is usually found in the advanced stages of the tumor. Moreover, some of the drugs used in chemotherapy, such as 5-fluorouracil and erythropoietin, are also capable of causing HVS through their respective pathways. Clinically, the viscosity of a patient's blood sample is measured by a rotary rheometer to estimate the risk of hyperviscosity syndrome. However, the measurement of blood viscosity in vitro is easily affected by storage time, storage environment, and anticoagulants. In addition, the fluid conditions in the rheometer are quite different from those in natural blood vessels, making this method inappropriate for evaluating blood viscosity and its effects in vivo under physiological condition. Herein, we presented a novel magnetic resonance imaging method called local-saturation-and-delay imaging (LSDI). The radial distributions of flow velocity measured by LSDI are consistent with the Ultrasonic (US) method (Spearman correlation coefficient r = 0.990). But the result of LSDI is more stable than US (p < 0.0001). With the LSDI method, we can directly measure the radial distribution of diastolic flow velocity, and further use these data to calculate the whole blood relative viscosity (WBRV) and erythrocyte aggregation trend. It was a strong correlation between the results measured by LSDI and rotary rheometer in the group of rats given erythropoietin. Furthermore, experimental results in glioma rats indicate that LSDI is equivalent to a rheometer as a method for predicting the risk of hyperviscosity syndrome. Therefore, LSDI, as a non-invasive method, can effectively follow the changes in WBRV in rats and avoid the effect of blood sampling during the experiment on the results. In conclusion, LSDI is expected to become a novel method for real-time in vivo recognition of the cancer progression and the influence of drugs on blood viscosity and RBC aggregation.
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Affiliation(s)
- Haiwei Shan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Science—Wuhan National Laboratory for Optoelectronics, Wuhan, China,University of Chinese Academy of Sciences, Beijing, China
| | - Lei Shi
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Science—Wuhan National Laboratory for Optoelectronics, Wuhan, China,University of Chinese Academy of Sciences, Beijing, China
| | - Shuang Liu
- Department of Pediatrics, Affiliated Hospital of Changchun University of Traditional Chinese Medicine, Changchun, China
| | - Yaping Yuan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Science—Wuhan National Laboratory for Optoelectronics, Wuhan, China,University of Chinese Academy of Sciences, Beijing, China
| | - Hongchuang Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Science—Wuhan National Laboratory for Optoelectronics, Wuhan, China,University of Chinese Academy of Sciences, Beijing, China
| | - Shizhen Chen
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Science—Wuhan National Laboratory for Optoelectronics, Wuhan, China,University of Chinese Academy of Sciences, Beijing, China
| | - Xin Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Science—Wuhan National Laboratory for Optoelectronics, Wuhan, China,University of Chinese Academy of Sciences, Beijing, China,*Correspondence: Xin Zhou,
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9
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Tu Y, Li Q, Zhou Y, Ye Z, Wu C, Xie E, Li Y, Li P, Wu Y, Guo Z, Yu C, Zheng J, Gao Y. Empagliflozin inhibits coronary microvascular dysfunction and reduces cardiac pericyte loss in db/db mice. Front Cardiovasc Med 2022; 9:995216. [PMID: 36588571 PMCID: PMC9800791 DOI: 10.3389/fcvm.2022.995216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
Background Coronary microvascular dysfunction (CMD) is a pathophysiological feature of diabetic heart disease. However, whether sodium-glucose cotransporter 2 (SGLT2) inhibitors protect the cardiovascular system by alleviating CMD is not known. Objective We observed the protective effects of empagliflozin (EMPA) on diabetic CMD. Materials and methods The mice were randomly divided into a db/db group and a db/db + EMPA group, and db/m mice served as controls. At 8 weeks of age, the db/db + EMPA group was given empagliflozin 10 mg/(kg⋅d) by gavage for 8 weeks. Body weight, fasting blood glucose and blood pressure were dynamically observed. Cardiac systolic and diastolic function and coronary flow reserve (CFR) were detected using echocardiography. The coronary microvascular structure and distribution of cardiac pericytes were observed using immunofluorescence staining. Picrosirius red staining was performed to evaluate cardiac fibrosis. Results Empagliflozin lowered the increased fasting blood glucose levels of the db/db group. The left ventricular ejection fraction, left ventricular fractional shortening, E/A ratio and E/e' ratio were not significantly different between the three groups. CFR was decreased in the db/db group, but EMPA significantly improved CFR. In contrast to the sparse and abnormal expansion of coronary microvessels observed in the db/db group, the number of coronary microvessels was increased, and the capillary diameter was decreased in the db/db + EMPA group. The number and microvascular coverage of cardiac pericytes were reduced in the db/db mice but were improved by EMPA. The cardiac fibrosis was increased in db/db group and may alleviate by EMPA. Conclusion Empagliflozin inhibited CMD and reduced cardiac pericyte loss in diabetic mice.
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Affiliation(s)
- Yimin Tu
- Department of Cardiology, China-Japan Friendship School of Clinical Medicine, Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Qing Li
- Department of Cardiology, Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Yuanchen Zhou
- Department of Cardiology, Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Zixiang Ye
- Department of Cardiology, Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Chao Wu
- Department of Cardiology, Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Enmin Xie
- Department of Cardiology, China-Japan Friendship School of Clinical Medicine, Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yike Li
- Department of Cardiology, China-Japan Friendship School of Clinical Medicine, Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Peizhao Li
- Department of Cardiology, Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Yaxin Wu
- Department of Cardiology, Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Ziyu Guo
- Department of Cardiology, Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Changan Yu
- Department of Cardiology, China-Japan Friendship Hospital, Beijing, China
| | - Jingang Zheng
- Department of Cardiology, China-Japan Friendship School of Clinical Medicine, Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- Department of Cardiology, China-Japan Friendship Hospital, Beijing, China
| | - Yanxiang Gao
- Department of Cardiology, China-Japan Friendship School of Clinical Medicine, Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- Department of Cardiology, China-Japan Friendship Hospital, Beijing, China
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Liu P, Chen J, Qi J, Liu M, Zhang M, Xue Y, Li L, Liu Y, Shi J, Zhang Y, Chu L. Hesperetin ameliorates ischemia/hypoxia‐induced myocardium injury via inhibition of oxidative stress, apoptosis, and regulation of Ca
2+
homeostasis. Phytother Res 2022; 37:1787-1805. [PMID: 36437582 DOI: 10.1002/ptr.7693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/12/2022] [Accepted: 10/06/2022] [Indexed: 11/29/2022]
Abstract
Ischemia/hypoxia (I/H)-induced myocardial injury has a large burden worldwide. Hesperetin (HSP) has a cardioprotective effect, but the molecular mechanism underlying this is not clearly established. Here, we focused on the protective mechanisms of HSP against I/H-induced myocardium injury. H9c2 cardiomyocytes were challenged with CoCl2 for 22 h to imitate hypoxia after treatment groups received HSP for 4 h. The viability of H9c2 cardiomyocytes was evaluated, and cardiac function indices, reactive oxygen species, apoptosis, mitochondrial membrane potential (MMP), and intracellular Ca2+ concentration ([Ca2+ ]i ) were measured. L-type Ca2+ current (ICa-L ), myocardial contraction, and Ca2+ transients in isolated ventricular myocytes were also recorded. We found that HSP significantly increased the cell viability, and MMP while significantly decreasing cardiac impairment, oxidative stress, apoptosis, and [Ca2+ ]i caused by CoCl2 . Furthermore, HSP markedly attenuated ICa-L , myocardial contraction, and Ca2+ transients in a concentration-dependent manner. Our findings suggest a protective mechanism of HSP on I/H-induced myocardium injury by restoring oxidative balance, inhibiting apoptosis, improving mitochondrial function, and reducing Ca2+ influx via L-type Ca2+ channels (LTCCs). These data provide a new direction for HSP applied research as a LTCC inhibitor against I/H-induced myocardium injury.
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Affiliation(s)
- Panpan Liu
- School of Pharmacy Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
| | - Jian Chen
- School of Pharmacy Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
| | - Jiaying Qi
- School of Pharmacy Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
| | - Miaomiao Liu
- School of Pharmacy Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
| | - Muqing Zhang
- College of Integrative Medicine Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
| | - Yucong Xue
- School of Pharmacy Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
| | - Li Li
- School of Pharmacy Hebei Medical University Shijiazhuang Hebei People's Republic of China
| | - Yanshuang Liu
- College of Integrative Medicine Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
| | - Jing Shi
- Department of Scientifc Research Management The Fourth Hospital of Hebei Medical University Shijiazhuang Hebei People's Republic of China
| | - Yixin Zhang
- School of Pharmacy Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
- International Joint Research Center on Resource Utilization and Quality Evaluation of Traditional Chinese Medicine of Hebei Province Shijiazhuang Hebei People's Republic of China
| | - Li Chu
- School of Pharmacy Hebei University of Chinese Medicine Shijiazhuang Hebei People's Republic of China
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11
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Tomanek RJ. The coronary capillary bed and its role in blood flow and oxygen delivery: A review. Anat Rec (Hoboken) 2022; 305:3199-3211. [PMID: 35521832 PMCID: PMC9796134 DOI: 10.1002/ar.24951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 01/01/2023]
Abstract
The assumption that the coronary capillary blood flow is exclusively regulated by precapillary vessels is not supported by recent data. Rather, the complex coronary capillary bed has unique structural and geometric characteristics that invalidate many assumptions regarding red blood cell (RBC) transport, for example, data based on a single capillary or that increases in flow are the result of capillary recruitment. It is now recognized that all coronary capillaries are open and that their variations in flow are due to structural differences, local O2 demand and delivery, and variations in hematocrit. Recent data reveal that local mechanisms within the capillary bed regulate flow via signaling mechanisms involving RBC signaling and endothelial-associated pericytes that contract and relax in response to humoral and neural signaling. The discovery that pericytes respond to vasoactive signals (e.g., nitric oxide, phenylephrine, and adenosine) underscores the role of these cells in regulating capillary diameter and consequently RBC flux and oxygen delivery. RBCs also affect blood flow by sensing <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>P</mml:mi> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:msub> </mml:math> and releasing nitric oxide to facilitate relaxation of pericytes and a consequential capillary dilation. New data indicate that these signaling mechanisms allow control of blood flow in specific coronary capillaries according to their oxygen requirements. In conclusion, mechanisms in the coronary capillary bed facilitate RBC density and transit time, hematocrit, blood flow and O2 delivery, factors that decrease capillary heterogeneity. These findings have important clinical implications for myocardial ischemia and infarction, as well as other vascular diseases.
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Affiliation(s)
- Robert J. Tomanek
- Department of Anatomy and Cell Biology, Carver College of MedicineUniversity of IowaIowa CityIAUSA
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12
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SOGORSKI ALEXANDER, DOSTIBEGIAN MARYNA, LEHNHARDT MARCUS, WALLNER CHRISTOPH, WAGNER JOHANNESM, DADRAS MEHRAN, GLINSKI MAXIVON, KOLBENSCHLAG JONAS, BEHR BJÖRN. Postoperative Remote Ischemic Conditioning (RIC) significantly improves entire flap microcirculation beyond 4 hours. J Plast Reconstr Aesthet Surg 2022; 75:4003-4012. [DOI: 10.1016/j.bjps.2022.08.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 05/28/2022] [Accepted: 08/17/2022] [Indexed: 11/25/2022]
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13
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Shan T, Shuwen Z, Hengbin W, Min Z. Can EAT be an INOCA goalkeeper. Front Endocrinol (Lausanne) 2022; 13:1028429. [PMID: 36743934 PMCID: PMC9895377 DOI: 10.3389/fendo.2022.1028429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/16/2022] [Indexed: 01/22/2023] Open
Abstract
Ischemia with non-obstructive coronary artery (INOCA) is a blind spot of coronary artery disease (CAD). Such patients are often reassured but offered no specific care, that lead to a heightened risk of adverse cerebrovascular disease (CVD) outcomes. Epicardial adipose tissue (EAT) is proven to correlate independently with CAD and its severity, but it is unknown whether EAT is a specific and sensitive indicator of INOCA. This review focuses on the INOCA epidemiology and related factors, as well as the association between EAT.
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Affiliation(s)
- Tong Shan
- Center of Geriatrics, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), Haikou, China
| | - Zheng Shuwen
- Clinical College, Hainan Medical University, Haikou, China
| | - Wu Hengbin
- Clinical College, Hainan Medical University, Haikou, China
| | - Zeng Min
- Center of Geriatrics, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), Haikou, China
- *Correspondence: Zeng Min,
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14
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Elucidating the combined effect of intermittent hypoxia training and acetazolamide on hypoxia induced hematological and physiological changes. Curr Res Physiol 2022; 5:327-337. [PMID: 35880035 PMCID: PMC9307424 DOI: 10.1016/j.crphys.2022.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 07/05/2022] [Accepted: 07/11/2022] [Indexed: 11/25/2022] Open
Abstract
As the number of people travelling to altitude increases, the risk of life threatening medical emergencies also increases. It is important that we have effective strategies to minimize the risk of altitude illness. In this study, an attempt was made to investigate the combined effect of non-pharmacological (Intermittent hypoxia training; IHT) and pharmacological (acetazolamide; ACZ) intervention as a prophylactic strategy in order to minimize the risk of high altitude hypoxic related problems using rats as an animal model. Male Sprague Dawley rats were subjected to IHT for 4 h consecutively for 5 days at 12% FiO2 under normobaric conditions with and without oral ACZ administration at 25 mg/kg body weight. Validation of the intervention was performed by exposing the rats to extreme hypoxia (EH) at 8% FiO2 to further assess the effect of IHT and ACZ on hypoxic acclimatization. The principal findings of this study is that the combined effect of IHT and ACZ improves the arterial oxygenation by alterations in hemodynamics and in blood gasometry, thereby resulting into an increase in the oxygen carrying capacity of the blood with increase in SpO2 (peripheral oxygen saturation). The present study showed that the combined effect of IHT with ACZ could be refined as a prophylactic measure for better outcomes during altitude ascent and rapid altitude acclimatization rather than IHT or ACZ alone. Combination of IHT with ACZ attenuates the inhibitory effect of respiratory alkalosis. It also minimizes pathological changes in hematology and blood gas. The strategy improved the oxygen carrying capacity of the blood by increasing SpO2. Thus, it leads to ventilatory Acclimatization. The combined treatment could be refined as a prophylactic measure for altitude maladies.
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15
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Lan D, Shang Y, Su H, Liang M, Liu Y, Li H, Feng Q, Cao X, Dong H. Facile Fabrication of Hollow Hydrogel Microfiber via 3D Printing-Assisted Microfluidics and Its Application as a Biomimetic Blood Capillary. ACS Biomater Sci Eng 2021; 7:4971-4981. [PMID: 34503336 DOI: 10.1021/acsbiomaterials.1c00980] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Simulating the structure and function of blood capillaries is very important for an in-depth insight into their role in the human body and treatment of capillary-related diseases. Due to the similar composition and structure, hollow hydrogel microfibers are well-recognized as potential biomimetic blood capillaries. In this paper, we report a novel, facile, and reproducible method to fabricate coaxial microfluidic chips via 3D printing-assisted soft lithography and then hollow hydrogel microfibers using the as-prepared coaxial microfluidic chips. Instead of traditional photoresist-based lithography, 3D printing of gelatin hydrogel under various extrusion pressures is used to construct sacrificial templates of coaxial microfluidic chips. Various solid and hollow hydrogel microfibers with complicated and hierarchical structures can be obtained via multitype coaxial microfluidic chips or a combination of coaxial microfluidic fabrication and post-treatment. The as-formed hollow hydrogel microfibers are evaluated in detail as biomimetic blood capillaries, including physicochemical and cytological properties. Our results prove that the hollow hydrogel microfibers exhibit excellent mass transport capacity, hemocompatibility, semipermeability, and mechanical strength, and their barrier function can be further enhanced in the presence of endothelial cells. Overall, our 3D printing-assisted fabrication strategy provides a new technique to construct microfluidic chips with complicated 3D microchannels, and the resulting hollow hydrogel microfibers are promising candidates for blood capillaries.
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Affiliation(s)
- Dongxu Lan
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China
| | - Yulian Shang
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China
| | - Hongxian Su
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China
| | - Minhua Liang
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China
| | - Yang Liu
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China
| | - Haofei Li
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China
| | - Qi Feng
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China
| | - Xiaodong Cao
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China.,Key Laboratory of Biomedical Materials and Engineering of the Ministry of Education, South China University of Technology, Guangzhou 510006, P. R. China
| | - Hua Dong
- Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China.,National Engineering Research Center for Tissue Restoration and Reconstruction (NERC-TRR), Guangzhou 510006, China.,Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510641, China
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16
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Terman D, Chen L, Hannawi Y. Mathematical modeling of cerebral capillary blood flow heterogeneity and its effect on brain tissue oxygen levels. J Theor Biol 2021; 527:110817. [PMID: 34157352 DOI: 10.1016/j.jtbi.2021.110817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/06/2021] [Accepted: 06/15/2021] [Indexed: 11/29/2022]
Abstract
Maintaining cerebral blood flow is critical for adequate neuronal function. Previous computational models of brain capillary networks have predicted that heterogeneous cerebral capillary flow patterns result in lower brain tissue partial oxygen pressures PO2). However, these previous models have often considered simple capillary networks in terms of their geometric properties. In this current work, we developed and analyzed computational models of brain capillary networks to determine how perturbations of network properties impact tissue oxygen levels. The models include variabilities in both their geometric (segment lengths and diameters) and three-dimensional, topological structure. Two classes of capillary network models are considered. The first consists of equations for the oxygen partial pressure, PO2, in both a capillary network and the surrounding tissue. In order to gain insight into the behavior of this detailed model, we also consider a reduced model for changes in PO2 in just the capillary network. The main result is that for a general class of networks, random perturbations of either segment diameters or conductances will always, on average, decrease the average tissue oxygen levels. This result is supported through both simulations of the models and mathematical analysis. Our results promise to expand our understanding of cerebral capillary blood flow and its impact on the brain function in health and disease.
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Affiliation(s)
- David Terman
- Department of Mathematics, The Ohio State University, Columbus, OH 43210 USA.
| | - Liam Chen
- Department of Mathematics, The Ohio State University, Columbus, OH 43210 USA
| | - Yousef Hannawi
- Division of Cerebrovascular Diseases and Neurocritical Care, Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210 USA
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17
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Østergaard L. SARS CoV-2 related microvascular damage and symptoms during and after COVID-19: Consequences of capillary transit-time changes, tissue hypoxia and inflammation. Physiol Rep 2021; 9:e14726. [PMID: 33523608 PMCID: PMC7849453 DOI: 10.14814/phy2.14726] [Citation(s) in RCA: 148] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/15/2022] Open
Abstract
Corona virus disease 2019 (COVID-19) causes symptoms from multiple organs after infection by severe acute respiratory syndrome corona virus 2 (SARS CoV-2). They range from early, low blood oxygen levels (hypoxemia) without breathlessness ("silent hypoxia"), delirium, rashes, and loss of smell (anosmia), to persisting chest pain, muscle weakness and -pain, fatigue, confusion, memory problems and difficulty to concentrate ("brain fog"), mood changes, and unexpected onset of hypertension or diabetes. SARS CoV-2 affects the microcirculation, causing endothelial cell swelling and damage (endotheliitis), microscopic blood clots (microthrombosis), capillary congestion, and damage to pericytes that are integral to capillary integrity and barrier function, tissue repair (angiogenesis), and scar formation. Similar to other instances of critical illness, COVID-19 is also associated with elevated cytokine levels in the systemic circulation. This review examines how capillary damage and inflammation may contribute to these acute and persisting COVID-19 symptoms by interfering with blood and tissue oxygenation and with brain function. Undetectable by current diagnostic methods, capillary flow disturbances limit oxygen diffusion exchange in lungs and tissue and may therefore cause hypoxemia and tissue hypoxia. The review analyzes the combined effects of COVID-19-related capillary damage, pre-existing microvascular changes, and upstream vascular tone on tissue oxygenation in key organs. It identifies a vicious cycle, as infection- and hypoxia-related inflammation cause capillary function to deteriorate, which in turn accelerates hypoxia-related inflammation and tissue damage. Finally, the review addresses the effects of low oxygen and high cytokine levels in brain tissue on neurotransmitter synthesis and mood. Methods to assess capillary functions in human organs and therapeutic means to protect capillary functions and stimulate capillary bed repair may prove important for the individualized management of COVID-19 patients and targeted rehabilitation strategies.
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Affiliation(s)
- Leif Østergaard
- Neuroradiology Research UnitSection of NeuroradiologyDepartment of RadiologyAarhus University HospitalAarhusDenmark
- Center of Functionally Integrative NeuroscienceDepartment of Clinical MedicineAarhus UniversityAarhusDenmark
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18
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Budharaju H, Subramanian A, Sethuraman S. Recent advancements in cardiovascular bioprinting and bioprinted cardiac constructs. Biomater Sci 2021; 9:1974-1994. [DOI: 10.1039/d0bm01428a] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Three-dimensionally bioprinted cardiac constructs with biomimetic bioink helps to create native-equivalent cardiac tissues to treat patients with myocardial infarction.
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Affiliation(s)
- Harshavardhan Budharaju
- Tissue Engineering & Additive Manufacturing (TEAM) Lab
- Centre for Nanotechnology & Advanced Biomaterials
- ACBDE Innovation Centre
- School of Chemical & Biotechnology
- SASTRA Deemed to be University
| | - Anuradha Subramanian
- Tissue Engineering & Additive Manufacturing (TEAM) Lab
- Centre for Nanotechnology & Advanced Biomaterials
- ACBDE Innovation Centre
- School of Chemical & Biotechnology
- SASTRA Deemed to be University
| | - Swaminathan Sethuraman
- Tissue Engineering & Additive Manufacturing (TEAM) Lab
- Centre for Nanotechnology & Advanced Biomaterials
- ACBDE Innovation Centre
- School of Chemical & Biotechnology
- SASTRA Deemed to be University
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19
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Roy TK, Secomb TW. Effects of impaired microvascular flow regulation on metabolism-perfusion matching and organ function. Microcirculation 2020; 28:e12673. [PMID: 33236393 DOI: 10.1111/micc.12673] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022]
Abstract
Impaired tissue oxygen delivery is a major cause of organ damage and failure in critically ill patients, which can occur even when systemic parameters, including cardiac output and arterial hemoglobin saturation, are close to normal. This review addresses oxygen transport mechanisms at the microcirculatory scale, and how hypoxia may occur in spite of adequate convective oxygen supply. The structure of the microcirculation is intrinsically heterogeneous, with wide variations in vessel diameters and flow pathway lengths, and consequently also in blood flow rates and oxygen levels. The dynamic processes of structural adaptation and flow regulation continually adjust microvessel diameters to compensate for heterogeneity, redistributing flow according to metabolic needs to ensure adequate tissue oxygenation. A key role in flow regulation is played by conducted responses, which are generated and propagated by endothelial cells and signal upstream arterioles to dilate in response to local hypoxia. Several pathophysiological conditions can impair local flow regulation, causing hypoxia and tissue damage leading to organ failure. Therapeutic measures targeted to systemic parameters may not address or may even worsen tissue oxygenation at the microvascular level. Restoration of tissue oxygenation in critically ill patients may depend on restoration of endothelial cell function, including conducted responses.
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Affiliation(s)
- Tuhin K Roy
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, AZ, 85724, USA
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20
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Ischemic Heart Disease Pathophysiology Paradigms Overview: From Plaque Activation to Microvascular Dysfunction. Int J Mol Sci 2020; 21:ijms21218118. [PMID: 33143256 PMCID: PMC7663258 DOI: 10.3390/ijms21218118] [Citation(s) in RCA: 129] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/27/2020] [Accepted: 10/27/2020] [Indexed: 02/06/2023] Open
Abstract
Ischemic heart disease still represents a large burden on individuals and health care resources worldwide. By conventions, it is equated with atherosclerotic plaque due to flow-limiting obstruction in large-medium sized coronary arteries. However, clinical, angiographic and autoptic findings suggest a multifaceted pathophysiology for ischemic heart disease and just some cases are caused by severe or complicated atherosclerotic plaques. Currently there is no well-defined assessment of ischemic heart disease pathophysiology that satisfies all the observations and sometimes the underlying mechanism to everyday ischemic heart disease ward cases is misleading. In order to better examine this complicated disease and to provide future perspectives, it is important to know and analyze the pathophysiological mechanisms that underline it, because ischemic heart disease is not always determined by atherosclerotic plaque complication. Therefore, in order to have a more complete comprehension of ischemic heart disease we propose an overview of the available pathophysiological paradigms, from plaque activation to microvascular dysfunction.
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21
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Østergaard L. Blood flow, capillary transit times, and tissue oxygenation: the centennial of capillary recruitment. J Appl Physiol (1985) 2020; 129:1413-1421. [PMID: 33031017 DOI: 10.1152/japplphysiol.00537.2020] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The transport of oxygen between blood and tissue is limited by blood's capillary transit time, understood as the time available for diffusion exchange before blood returns to the heart. If all capillaries contribute equally to tissue oxygenation at all times, this physical limitation would render vasodilation and increased blood flow insufficient means to meet increased metabolic demands in the heart, muscle, and other organs. In 1920, Danish physiologist August Krogh was awarded the Nobel Prize in Physiology or Medicine for his mathematical and quantitative, experimental demonstration of a solution to this conceptual problem: capillary recruitment, the active opening of previously closed capillaries to meet metabolic demands. Today, capillary recruitment is still mentioned in textbooks. When we suspect symptoms might represent hypoxia of a vascular origin, however, we search for relevant, flow-limiting conditions in our patients and rarely ascribe hypoxia or hypoxemia to short capillary transit times. This review describes how natural changes in capillary transit-time heterogeneity (CTH) and capillary hematocrit (HCT) across open capillaries during blood flow increases can account for a match of oxygen availability to metabolic demands in normal tissue. CTH and HCT depend on a number of factors: on blood properties, including plasma viscosity, the number, size, and deformability of blood cells, and blood cell interactions with capillary endothelium; on anatomical factors including glycocalyx, endothelial cells, basement membrane, and pericytes that affect the capillary diameter; and on any external compression. The review describes how risk factor- and disease-related changes in CTH and HCT interfere with flow-metabolism coupling and tissue oxygenation and discusses whether such capillary dysfunction contributes to vascular disease pathology.
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Affiliation(s)
- Leif Østergaard
- Center of Functionally Integrative Neuroscience, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Neuroradiology Research Unit, Section of Neuroradiology, Department of Radiology, Aarhus University Hospital, Aarhus, Denmark
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22
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Poole DC, Pittman RN, Musch TI, Østergaard L. August Krogh's theory of muscle microvascular control and oxygen delivery: a paradigm shift based on new data. J Physiol 2020; 598:4473-4507. [PMID: 32918749 DOI: 10.1113/jp279223] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022] Open
Abstract
August Krogh twice won the prestigious international Steegen Prize, for nitrogen metabolism (1906) and overturning the concept of active transport of gases across the pulmonary epithelium (1910). Despite this, at the beginning of 1920, the consummate experimentalist was relatively unknown worldwide and even among his own University of Copenhagen faculty. But, in early 1919, he had submitted three papers to Dr Langley, then editor of The Journal of Physiology in England. These papers coalesced anatomical observations of skeletal muscle capillary numbers with O2 diffusion theory to propose a novel active role for capillaries that explained the prodigious increase in blood-muscle O2 flux from rest to exercise. Despite his own appraisal of the first two papers as "rather dull" to his friend, the eminent Cambridge respiratory physiologist, Joseph Barcroft, Krogh believed that the third one, dealing with O2 supply and capillary regulation, was"interesting". These papers, which won Krogh an unopposed Nobel Prize for Physiology or Medicine in 1920, form the foundation for this review. They single-handedly transformed the role of capillaries from passive conduit and exchange vessels, functioning at the mercy of their upstream arterioles, into independent contractile units that were predominantly closed at rest and opened actively during muscle contractions in a process he termed 'capillary recruitment'. Herein we examine Krogh's findings and some of the experimental difficulties he faced. In particular, the boundary conditions selected for his model (e.g. heavily anaesthetized animals, negligible intramyocyte O2 partial pressure, binary open-closed capillary function) have not withstood the test of time. Subsequently, we update the reader with intervening discoveries that underpin our current understanding of muscle microcirculatory control and place a retrospectroscope on Krogh's discoveries. The perspective is presented that the imprimatur of the Nobel Prize, in this instance, may have led scientists to discount compelling evidence. Much as he and Marie Krogh demonstrated that active transport of gases across the blood-gas barrier was unnecessary in the lung, capillaries in skeletal muscle do not open and close spontaneously or actively, nor is this necessary to account for the increase in blood-muscle O2 flux during exercise. Thus, a contemporary model of capillary function features most muscle capillaries supporting blood flow at rest, and, rather than capillaries actively vasodilating from rest to exercise, increased blood-myocyte O2 flux occurs predominantly via elevating red blood cell and plasma flux in already flowing capillaries. Krogh is lauded for his brilliance as an experimentalist and for raising scientific questions that led to fertile avenues of investigation, including the study of microvascular function.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University Manhattan, Manhattan, KS, 66506, USA
| | - Roland N Pittman
- Department of Physiology and Biophysics, Virginia Commonwealth University Richmond, Richmond, VA, 23298-0551, USA
| | - Timothy I Musch
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University Manhattan, Manhattan, KS, 66506, USA
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
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23
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Vancheri F, Longo G, Vancheri S, Henein M. Coronary Microvascular Dysfunction. J Clin Med 2020; 9:E2880. [PMID: 32899944 PMCID: PMC7563453 DOI: 10.3390/jcm9092880] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/02/2020] [Accepted: 09/02/2020] [Indexed: 01/09/2023] Open
Abstract
Many patients with chest pain undergoing coronary angiography do not show significant obstructive coronary lesions. A substantial proportion of these patients have abnormalities in the function and structure of coronary microcirculation due to endothelial and smooth muscle cell dysfunction. The coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac oxygen requirements. Impairment of this mechanism, defined as coronary microvascular dysfunction (CMD), carries an increased risk of adverse cardiovascular clinical outcomes. Coronary endothelial dysfunction accounts for approximately two-thirds of clinical conditions presenting with symptoms and signs of myocardial ischemia without obstructive coronary disease, termed "ischemia with non-obstructive coronary artery disease" (INOCA) and for a small proportion of "myocardial infarction with non-obstructive coronary artery disease" (MINOCA). More frequently, the clinical presentation of INOCA is microvascular angina due to CMD, while some patients present vasospastic angina due to epicardial spasm, and mixed epicardial and microvascular forms. CMD may be associated with focal and diffuse epicardial coronary atherosclerosis, which may reinforce each other. Both INOCA and MINOCA are more common in females. Clinical classification of CMD includes the association with conditions in which atherosclerosis has limited relevance, with non-obstructive atherosclerosis, and with obstructive atherosclerosis. Several studies already exist which support the evidence that CMD is part of systemic microvascular disease involving multiple organs, such as brain and kidney. Moreover, CMD is strongly associated with the development of heart failure with preserved ejection fraction (HFpEF), diabetes, hypertensive heart disease, and also chronic inflammatory and autoimmune diseases. Since coronary microcirculation is not visible on invasive angiography or computed tomographic coronary angiography (CTCA), the diagnosis of CMD is usually based on functional assessment of microcirculation, which can be performed by both invasive and non-invasive methods, including the assessment of delayed flow of contrast during angiography, measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), evaluation of angina induced by intracoronary acetylcholine infusion, and assessment of myocardial perfusion by positron emission tomography (PET) and magnetic resonance (CMR).
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Affiliation(s)
- Federico Vancheri
- Department of Internal Medicine, S.Elia Hospital, 93100 Caltanissetta, Italy
| | - Giovanni Longo
- Cardiovascular and Interventional Department, S.Elia Hospital, 93100 Caltanissetta, Italy;
| | - Sergio Vancheri
- Radiology Department, I.R.C.C.S. Policlinico San Matteo, 27100 Pavia, Italy;
| | - Michael Henein
- Institute of Public Health and Clinical Medicine, Umea University, SE-90187 Umea, Sweden;
- Department of Fluid Mechanics, Brunel University, Middlesex, London UB8 3PH, UK
- Molecular and Nuclear Research Institute, St George’s University, London SW17 0RE, UK
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24
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Wright WS, Eshaq RS, Lee M, Kaur G, Harris NR. Retinal Physiology and Circulation: Effect of Diabetes. Compr Physiol 2020; 10:933-974. [PMID: 32941691 PMCID: PMC10088460 DOI: 10.1002/cphy.c190021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In this article, we present a discussion of diabetes and its complications, including the macrovascular and microvascular effects, with the latter of consequence to the retina. We will discuss the anatomy and physiology of the retina, including aspects of metabolism and mechanisms of oxygenation, with the latter accomplished via a combination of the retinal and choroidal blood circulations. Both of these vasculatures are altered in diabetes, with the retinal circulation intimately involved in the pathology of diabetic retinopathy. The later stages of diabetic retinopathy involve poorly controlled angiogenesis that is of great concern, but in our discussion, we will focus more on several alterations in the retinal circulation occurring earlier in the progression of disease, including reductions in blood flow and a possible redistribution of perfusion that may leave some areas of the retina ischemic and hypoxic. Finally, we include in this article a more recent area of investigation regarding the diabetic retinal vasculature, that is, the alterations to the endothelial surface layer that normally plays a vital role in maintaining physiological functions. © 2020 American Physiological Society. Compr Physiol 10:933-974, 2020.
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Affiliation(s)
- William S Wright
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, South Carolina, USA
| | - Randa S Eshaq
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Minsup Lee
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Gaganpreet Kaur
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Norman R Harris
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
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25
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Harris NR, Leskova W, Kaur G, Eshaq RS, Carter PR. Blood flow distribution and the endothelial surface layer in the diabetic retina. Biorheology 2020; 56:181-189. [PMID: 30958328 PMCID: PMC10082436 DOI: 10.3233/bir-180200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diabetic retinopathy is known as a microvascular complication of hyperglycemia, with a breakdown of the blood-retinal barrier, loss of pericytes, formation of microhemorrhages, early decreases in perfusion and areas of ischemia, with the latter speculated to induce the eventual proliferative, angiogenic phase of the disease. Our animal models of diabetic retinopathy demonstrate similar decreases in retinal blood flow as seen in the early stages of diabetes in humans. Our studies also show an alteration in the retinal distribution of red blood cells, with the deep capillary layer receiving a reduced fraction, and with flow being diverted more towards the superficial vascular layer. Normal red blood cell distribution is dependent on the presence of the endothelial surface layer, specifically the glycocalyx, which has been reported to be partially lost in the diabetic retina of both humans and animals. This review addresses these two phenomena in diabetes: altered perfusion patterns and loss of the glycocalyx, with a possible connection between the two.
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Affiliation(s)
- Norman R Harris
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Wendy Leskova
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Gaganpreet Kaur
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Randa S Eshaq
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Patsy R Carter
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
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26
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van de Wouw J, Sorop O, van Drie RWA, van Duin RWB, Nguyen ITN, Joles JA, Verhaar MC, Merkus D, Duncker DJ. Perturbations in myocardial perfusion and oxygen balance in swine with multiple risk factors: a novel model of ischemia and no obstructive coronary artery disease. Basic Res Cardiol 2020; 115:21. [PMID: 32100119 PMCID: PMC7042191 DOI: 10.1007/s00395-020-0778-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 01/14/2020] [Indexed: 12/12/2022]
Abstract
Comorbidities of ischemic heart disease, including diabetes mellitus (DM), hypercholesterolemia (HC) and chronic kidney disease (CKD), are associated with coronary microvascular dysfunction (CMD). Increasing evidence suggests that CMD may contribute to myocardial ‘Ischemia and No Obstructive Coronary Artery disease’ (INOCA). In the present study, we tested the hypothesis that CMD results in perturbations in myocardial perfusion and oxygen delivery using a novel swine model with multiple comorbidities. DM (streptozotocin), HC (high-fat diet) and CKD (renal embolization) were induced in 10 female swine (DM + HC + CKD), while 12 healthy female swine on a normal diet served as controls (Normal). After 5 months, at a time when coronary atherosclerosis was still negligible, myocardial perfusion, metabolism, and function were studied at rest and during treadmill exercise. DM + HC + CKD animals showed hyperglycemia, hypercholesterolemia, and impaired kidney function. During exercise, DM + HC + CKD swine demonstrated perturbations in myocardial blood flow and oxygen delivery, necessitating a higher myocardial oxygen extraction—achieved despite reduced capillary density—resulting in lower coronary venous oxygen levels. Moreover, myocardial efficiency was lower, requiring higher oxygen consumption for a given level of myocardial work. These perturbations in myocardial oxygen balance were associated with lower myocardial lactate consumption, stroke volume, and LVdP/dtmax, suggestive of myocardial ischemia and dysfunction. Further analyses showed a reduction in adenosine-recruitable coronary flow reserve, but this was exclusively the result of an increase in basal coronary blood flow, while maximal coronary flow per gram of myocardium was maintained; the latter was consistent with the unchanged arteriolar wall/lumen ratio, arteriolar density and peri-arteriolar collagen content. However, isolated small arteries displayed selective blunting of endothelium-dependent vasodilation in response to bradykinin in DM + HC + CKD swine, suggesting that changes in coronary microvascular function rather than in structure contributed to the perturbations in myocardial oxygen delivery. In conclusion, common comorbidities in swine result in CMD, in the absence of appreciable atherosclerosis, which is severe enough to produce perturbations in myocardial oxygen balance, particularly during exercise, resembling key features of INOCA.
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Affiliation(s)
- Jens van de Wouw
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Oana Sorop
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Ruben W A van Drie
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Richard W B van Duin
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Isabel T N Nguyen
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jaap A Joles
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Daphne Merkus
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.,Walter Brendel Center of Experimental Medicine (WBex), LMU Munich, 81377, Munich, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance (MHA), 81377, Munich, Germany
| | - Dirk J Duncker
- Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
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27
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Torres Filho IP, Barraza D, Hildreth K, Williams C, Dubick MA. Cremaster muscle perfusion, oxygenation, and heterogeneity revealed by a new automated acquisition system in a rodent model of prolonged hemorrhagic shock. J Appl Physiol (1985) 2019; 127:1548-1561. [PMID: 31670599 DOI: 10.1152/japplphysiol.00570.2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Local blood flow/oxygen partial pressure (Po2) distributions and flow-Po2 relationships are physiologically relevant. They affect the pathophysiology and treatment of conditions like hemorrhagic shock (HS), but direct noninvasive measures of flow, Po2, and their heterogeneity during prolonged HS are infrequently presented. To fill this void, we report the first quantitative evaluation of flow-Po2 relationships and heterogeneities in normovolemia and during several hours of HS using noninvasive, unbiased, automated acquisition. Anesthetized rats were subjected to tracheostomy, arterial/venous catheterizations, cremaster muscle exteriorization, hemorrhage (40% total blood volume), and laparotomy. Control animals equally instrumented were not subjected to hemorrhage/laparotomy. Every 0.5 h for 4.5 h, noninvasive laser speckle contrast imaging and phosphorescence quenching were employed for nearly 7,000 flow/Po2 measurements in muscles from eight animals, using an automated system. Precise alignment of 16 muscle areas allowed overlapping between flow and oxygenation measurements to evaluate spatial heterogeneity, and repeated measurements were used to estimate temporal heterogeneity. Systemic physiological parameters and blood chemistry were simultaneously assessed by blood samplings replaced with crystalloids. Hemodilution was associated with local hypoxia, but increased flow prevented major oxygen delivery decline. Adding laparotomy and prolonged HS resulted in hypoxia, ischemia, decreased tissue oxygen delivery, and logarithmic flow/Po2 relationships in most regions. Flow and Po2 spatial heterogeneities were higher than their respective temporal heterogeneities, although this did not change significantly over the studied period. This quantitative framework establishes a basis for evaluating therapies aimed at restoring muscle homeostasis, positively impacting outcomes of civilian and military trauma/HS victims.NEW & NOTEWORTHY This is the first study on flow-Po2 relationships during normovolemia, hemodilution, and prolonged hemorrhagic shock using noninvasive methods in multiple skeletal muscle areas of monitored animals. Automated flow/Po2 measurements revealed temporal/spatial heterogeneities, hypoxia, ischemia, and decreased tissue oxygen delivery after trauma/severe hemorrhage. Hemodilution was associated with local hypoxia, but hyperemia prevented a major decline in oxygen delivery. This framework provides a quantitative basis for testing therapeutics that positively impacts muscle homeostasis and outcomes of trauma/hemorrhagic shock victims.
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Affiliation(s)
- Ivo P Torres Filho
- Damage Control Resuscitation, United States Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - David Barraza
- Damage Control Resuscitation, United States Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Kim Hildreth
- Damage Control Resuscitation, United States Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Charnae Williams
- Damage Control Resuscitation, United States Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Michael A Dubick
- Damage Control Resuscitation, United States Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
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Zhang X, Dong H, Liu Y, Han J, Tang S, Si J. Retracted: Tetramethylpyrazine partially relieves hypoxia-caused damage of cardiomyocytes H9c2 by downregulation of miR-449a. J Cell Physiol 2019; 234:15098-15107. [PMID: 30770559 DOI: 10.1002/jcp.28151] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/02/2019] [Indexed: 01/24/2023]
Abstract
Inadequate oxygen supply is probably one of the most important pathophysiological mechanisms of cardiomyocyte damage in ischemic heart disease. Tetramethylpyrazine (TMP, also known as ligustrazine) is the main active ingredient isolated from the rhizome of Ligusticum chuanxiong Hort. A previous study reported that the TMP could exert cardioprotective activity. This study aimed to explore the molecular mechanism of the protective effects of TMP on cardiomyocyte damage caused by hypoxia. The viability and apoptosis of cardiomyocytes H9c2 were detected using cell counting kit-8 assay and annexin V-FITC/PI staining, respectively. Quantitative reverse transcription polymerase chain reaction was conducted to measure the expression level of microRNA-449a (miR-449a). Cell transfection was performed to upregulate the expression level of miR-449a or downregulate the expression level of sirtuin 1 (Sirt1). The protein expression levels of Sirt1 and key factors involved in cell apoptosis and phosphatidylinositol 3-kinase/protein kinase 3 (PI3K/AKT) pathway were evaluated using western blot analysis. We found that the hypoxia incubation inhibited H9c2 viability, induced cell apoptosis, and inactivated the PI3K/AKT pathway. TMP treatment partially relieved the hypoxia-caused H9c2 cell viability loss and apoptosis, as well as reversed the hypoxia-caused inactivation of the PI3K/AKT pathway. Moreover, TMP partially alleviated the upregulation of miR-449a in H9c2 cells caused by hypoxia. Overexpression of miR-449a weakened the effects of TMP on hypoxia-treated H9c2 cells. Furthermore, Sirt1 was a target gene of miR-449a. Knockdown of Sirt1 also weakened the effects of TMP on hypoxia-treated H9c2 cells. In conclusion, TMP partially relieved hypoxia-caused cardiomyocytes H9c2 viability loss and apoptosis at least through downregulating miR-499a, upregulating Sirt1, and then activating the PI3K/AKT pathway.
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Affiliation(s)
- Xuesong Zhang
- Department of Cardiology, Liaocheng People's Hospital, Liaocheng, China
| | - Huawei Dong
- Department of Cardiology, Liaocheng People's Hospital, Liaocheng, China
| | - Yong Liu
- Department of Cardiology, Liaocheng People's Hospital, Liaocheng, China
| | - Junxia Han
- Department of Cardiology, Heze Municipal Hospital, Heze, China
| | - Shouyi Tang
- Department of Cardiology, Heze Municipal Hospital, Heze, China
| | - Jingna Si
- Department of Cardiovascular Surgery, Heze Municipal Hospital, Heze, China
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Li B, Esipova TV, Sencan I, Kılıç K, Fu B, Desjardins M, Moeini M, Kura S, Yaseen MA, Lesage F, Østergaard L, Devor A, Boas DA, Vinogradov SA, Sakadžić S. More homogeneous capillary flow and oxygenation in deeper cortical layers correlate with increased oxygen extraction. eLife 2019; 8:42299. [PMID: 31305237 PMCID: PMC6636997 DOI: 10.7554/elife.42299] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 07/01/2019] [Indexed: 01/01/2023] Open
Abstract
Our understanding of how capillary blood flow and oxygen distribute across cortical layers to meet the local metabolic demand is incomplete. We addressed this question by using two-photon imaging of resting-state microvascular oxygen partial pressure (PO2) and flow in the whisker barrel cortex in awake mice. Our measurements in layers I-V show that the capillary red-blood-cell flux and oxygenation heterogeneity, and the intracapillary resistance to oxygen delivery, all decrease with depth, reaching a minimum around layer IV, while the depth-dependent oxygen extraction fraction is increased in layer IV, where oxygen demand is presumably the highest. Our findings suggest that more homogeneous distribution of the physiological observables relevant to oxygen transport to tissue is an important part of the microvascular network adaptation to local brain metabolism. These results will inform the biophysical models of layer-specific cerebral oxygen delivery and consumption and improve our understanding of the diseases that affect cerebral microcirculation.
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Affiliation(s)
- Baoqiang Li
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Tatiana V Esipova
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, United States.,Department of Chemistry, University of Pennsylvania, Philadelphia, United States
| | - Ikbal Sencan
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Kıvılcım Kılıç
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Michele Desjardins
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Mohammad Moeini
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montréal, Canada.,Research Centre, Montreal Heart Institute, Montréal, Canada
| | - Sreekanth Kura
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Mohammad A Yaseen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
| | - Frederic Lesage
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montréal, Canada.,Research Centre, Montreal Heart Institute, Montréal, Canada
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, United States.,Department of Radiology, University of California, San Diego, La Jolla, United States
| | - David A Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States.,Department of Biomedical Engineering, Boston University, Boston, United States
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, United States.,Department of Chemistry, University of Pennsylvania, Philadelphia, United States
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
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30
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Corliss BA, Mathews C, Doty R, Rohde G, Peirce SM. Methods to label, image, and analyze the complex structural architectures of microvascular networks. Microcirculation 2019; 26:e12520. [PMID: 30548558 PMCID: PMC6561846 DOI: 10.1111/micc.12520] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/31/2018] [Accepted: 11/26/2018] [Indexed: 12/30/2022]
Abstract
Microvascular networks play key roles in oxygen transport and nutrient delivery to meet the varied and dynamic metabolic needs of different tissues throughout the body, and their spatial architectures of interconnected blood vessel segments are highly complex. Moreover, functional adaptations of the microcirculation enabled by structural adaptations in microvascular network architecture are required for development, wound healing, and often invoked in disease conditions, including the top eight causes of death in the Unites States. Effective characterization of microvascular network architectures is not only limited by the available techniques to visualize microvessels but also reliant on the available quantitative metrics that accurately delineate between spatial patterns in altered networks. In this review, we survey models used for studying the microvasculature, methods to label and image microvessels, and the metrics and software packages used to quantify microvascular networks. These programs have provided researchers with invaluable tools, yet we estimate that they have collectively attained low adoption rates, possibly due to limitations with basic validation, segmentation performance, and nonstandard sets of quantification metrics. To address these existing constraints, we discuss opportunities to improve effectiveness, rigor, and reproducibility of microvascular network quantification to better serve the current and future needs of microvascular research.
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Affiliation(s)
- Bruce A. Corliss
- Department of Biomedical EngineeringUniversity of VirginiaCharlottesvilleVirginia
| | - Corbin Mathews
- Department of Biomedical EngineeringUniversity of VirginiaCharlottesvilleVirginia
| | - Richard Doty
- Department of Biomedical EngineeringUniversity of VirginiaCharlottesvilleVirginia
| | - Gustavo Rohde
- Department of Biomedical EngineeringUniversity of VirginiaCharlottesvilleVirginia
| | - Shayn M. Peirce
- Department of Biomedical EngineeringUniversity of VirginiaCharlottesvilleVirginia
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31
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Kumowski N, Hegelmaier T, Kolbenschlag J, Mainka T, Michel-Lauter B, Maier C. Short-Term Glucocorticoid Treatment Normalizes the Microcirculatory Response to Remote Ischemic Conditioning in Early Complex Regional Pain Syndrome. Pain Pract 2018; 19:168-175. [PMID: 30269438 DOI: 10.1111/papr.12730] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/13/2018] [Accepted: 08/31/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND The early phase of complex regional pain syndrome (CRPS) is characterized by an inflammatory state and therefore often treated with anti-inflammatory acting glucocorticoids. Recently, we demonstrated that remote ischemic conditioning (RIC), a cyclic application of nondamaging ischemia on a remote extremity, reduces blood flow and increases oxygen extraction in the CRPS-affected extremity. AIM The aim of the presented study was to analyze the effect of short-term pain treatment including glucocorticoid pulse treatment on the RIC-induced perfusion parameters. METHOD Independently from the study, pain treatment was started with an oral glucocorticoid pulse (180 to 360 mg prednisolone) in 12 patients with CRPS (disease duration < 1 year). RIC was conducted before and after pulse treatment. Three cycles of 5 minutes ischemia and 10 minutes reperfusion were applied to the contralateral limb. Blood flow, tissue oxygenation, and oxygen extraction fraction were assessed ipsilateral before and during RIC. Current pain was assessed on the numeric rating scale (0 to 10), and finger-palm distance was measured. RESULTS Pain level (5.8 ± 1.5 vs. 3.1 ± 1.1) and finger-palm distance (5 ± 1.9 cm vs. 3.7 ± 1.9 cm) were decreased significantly by the treatment. RIC decreased blood flow by 32.8% ± 42.8% (P < 0.05) and increased oxygen extraction fraction by 8.5% ± 10.3% (P < 0.05) solely before the treatment. After treatment, all parameters remained unchanged after RIC (P < 0.05 vs. before), comparable to healthy subjects. CONCLUSION Confirming previous results, RIC presumably unmasks luxury perfusion in untreated CRPS patients. In accordance with the clinical improvement, the short-term pain treatment with glucocorticoids as major component normalizes impaired perfusion. These results might underline the rationale for anti-inflammatory treatment in early-phase CRPS.
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Affiliation(s)
- Nina Kumowski
- Department of Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University, Bochum, Germany
| | - Tobias Hegelmaier
- Department of Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University, Bochum, Germany.,Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany
| | - Jonas Kolbenschlag
- Department of Hand-, Plastic, Reconstructive and Burn Surgery, BG Trauma Center Tübingen, Eberhard Karls University, Tübingen, Germany
| | - Tina Mainka
- Department of Neurology, Charité University Medicine Berlin, Berlin, Germany
| | - Beate Michel-Lauter
- Department of Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University, Bochum, Germany
| | - Christoph Maier
- Department of Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University, Bochum, Germany
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32
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Østergaard L, Jørgensen MB, Knudsen GM. Low on energy? An energy supply-demand perspective on stress and depression. Neurosci Biobehav Rev 2018; 94:248-270. [DOI: 10.1016/j.neubiorev.2018.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 07/09/2018] [Accepted: 08/13/2018] [Indexed: 12/17/2022]
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33
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McClatchey PM, Frisbee JC, Reusch JEB. A conceptual framework for predicting and addressing the consequences of disease-related microvascular dysfunction. Microcirculation 2018; 24. [PMID: 28135021 DOI: 10.1111/micc.12359] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/25/2017] [Indexed: 12/20/2022]
Abstract
OBJECTIVE A growing body of evidence indicates that impaired microvascular perfusion plays a pathological role in a number of diseases. This manuscript aims to better define which aspects of microvascular perfusion are important, what mass transport processes (eg, insulin action, tissue oxygenation) may be impacted, and what therapies might reverse these pathologies. METHODS We derive a theory of microvascular perfusion and solute flux drawing from established relationships in mass transport and anatomy. We then apply this theory to predict relationships between microvascular perfusion parameters and microvascular solute flux. RESULTS For convection-limited exchange processes (eg, pulmonary oxygen uptake), our model predicts that bulk blood flow is of primary importance. For diffusion-limited exchange processes (eg, insulin action), our model predicts that perfused capillary density is of primary importance. For convection/diffusion co-limited exchange processes (eg, tissue oxygenation), our model predicts that various microvascular perfusion parameters interact in a complex, context-specific manner. We further show that our model can predict established mass transport defects in disease (eg, insulin resistance in diabetes). CONCLUSIONS The contributions of microvascular perfusion parameters to tissue-level solute flux can be described using a minimal mathematical model. Our results hold promise for informing therapeutic interventions targeting microvascular perfusion.
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Affiliation(s)
- Penn M McClatchey
- Division of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Medicine, Denver Veterans Affairs Medical Center, Denver, CO, USA
| | - Jefferson C Frisbee
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Jane E B Reusch
- Division of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.,Department of Medicine, Denver Veterans Affairs Medical Center, Denver, CO, USA
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34
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Lücker A, Secomb TW, Weber B, Jenny P. The Relation Between Capillary Transit Times and Hemoglobin Saturation Heterogeneity. Part 1: Theoretical Models. Front Physiol 2018; 9:420. [PMID: 29755365 PMCID: PMC5932636 DOI: 10.3389/fphys.2018.00420] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 04/04/2018] [Indexed: 12/23/2022] Open
Abstract
Capillary dysfunction impairs oxygen supply to parenchymal cells and often occurs in Alzheimer's disease, diabetes and aging. Disturbed capillary flow patterns have been shown to limit the efficacy of oxygen extraction and can be quantified using capillary transit time heterogeneity (CTH). However, the transit time of red blood cells (RBCs) through the microvasculature is not a direct measure of their capacity for oxygen delivery. Here we examine the relation between CTH and capillary outflow saturation heterogeneity (COSH), which is the heterogeneity of blood oxygen content at the venous end of capillaries. Models for the evolution of hemoglobin saturation heterogeneity (HSH) in capillary networks were developed and validated using a computational model with moving RBCs. Two representative situations were selected: a Krogh cylinder geometry with heterogeneous hemoglobin saturation (HS) at the inflow, and a parallel array of four capillaries. The heterogeneity of HS after converging capillary bifurcations was found to exponentially decrease with a time scale of 0.15-0.21 s due to diffusive interaction between RBCs. Similarly, the HS difference between parallel capillaries also drops exponentially with a time scale of 0.12-0.19 s. These decay times are substantially smaller than measured RBC transit times and only weakly depend on the distance between microvessels. This work shows that diffusive interaction strongly reduces COSH on a small spatial scale. Therefore, we conclude that CTH influences COSH yet does not determine it. The second part of this study will focus on simulations in microvascular networks from the rodent cerebral cortex. Actual estimates of COSH and CTH will then be given.
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Affiliation(s)
- Adrien Lücker
- Department of Mechanical and Process Engineering, Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, AZ, United States
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Patrick Jenny
- Department of Mechanical and Process Engineering, Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
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35
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Pries AR, Reglin B. Coronary microcirculatory pathophysiology: can we afford it to remain a black box? Eur Heart J 2018; 38:478-488. [PMID: 26843279 PMCID: PMC5381591 DOI: 10.1093/eurheartj/ehv760] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 12/27/2015] [Indexed: 01/04/2023] Open
Abstract
Coronary microvascular networks play the key role in determining blood flow distribution in the heart. Matching local blood supply to tissue metabolic demand entails continuous adaptation of coronary vessels via regulation of smooth muscle tone and structural dilated vessel diameter. The importance of coronary microcirculation for relevant pathological conditions including angina in patients with normal or near-normal coronary angiograms [microvascular angina (MVA)] and heart failure with preserved ejection fraction (HFpEF) is increasingly recognized. For MVA, clinical studies have shown a prevalence of up to 40% in patients with suspected coronary artery disease and a relevant impact on adverse cardiovascular events including cardiac death, stroke, and heart failure. Despite a continuously increasing number of corresponding clinical studies, the knowledge on pathophysiological cause–effect relations involving coronary microcirculation is, however, still very limited. A number of pathophysiological hypotheses for MVA and HFpEF have been suggested but are not established to a degree, which would allow definition of nosological entities, stratification of affected patients, or development of effective therapeutic strategies. This may be related to a steep decline in experimental (animal) pathophysiological studies in this area during the last 15 years. Since technology to experimentally investigate microvascular pathophysiology in the beating heart is increasingly, in principle, available, a concerted effort to build ‘coronary microcirculatory observatories’ to close this gap and to accelerate clinical progress in this area is suggested.
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Affiliation(s)
- Axel R Pries
- Department of Physiology, Center for Cardiovascular Research, Charité, Charitéplatz 1, D-10117 Berlin, Germany.,Deutsches Herzzentrum Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Bettina Reglin
- Department of Physiology, Center for Cardiovascular Research, Charité, Charitéplatz 1, D-10117 Berlin, Germany
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36
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Takagi C, Ono K, Matsuo H, Nagano N, Nojima Y. Higher reticulocyte counts are associated with higher mortality rates in hemodialysis patients: a retrospective single-center cohort study. RENAL REPLACEMENT THERAPY 2017. [DOI: 10.1186/s41100-016-0084-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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37
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O'Farrell FM, Mastitskaya S, Hammond-Haley M, Freitas F, Wah WR, Attwell D. Capillary pericytes mediate coronary no-reflow after myocardial ischaemia. eLife 2017; 6:29280. [PMID: 29120327 PMCID: PMC5705208 DOI: 10.7554/elife.29280] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/08/2017] [Indexed: 12/22/2022] Open
Abstract
After cardiac ischaemia, a prolonged decrease of coronary microvascular perfusion often occurs even after flow is restored in an upstream artery. This 'no-reflow' phenomenon worsens patient prognosis. In the brain, after stroke, a similar post-ischaemic 'no-reflow' has been attributed to capillary constriction by contractile pericytes. We now show that occlusion of a rat coronary artery, followed by reperfusion, blocks 40% of cardiac capillaries and halves perfused blood volume within the affected region. Capillary blockages colocalised strongly with pericytes, where capillary diameter was reduced by 37%. The pericyte relaxant adenosine increased capillary diameter by 21% at pericyte somata, decreased capillary block by 25% and increased perfusion volume by 57%. Thus, cardiac pericytes constrict coronary capillaries and reduce microvascular blood flow after ischaemia, despite re-opening of the culprit artery. Cardiac pericytes are therefore a novel therapeutic target in ischaemic heart disease. Heart attacks occur when one of the arteries supplying blood to the heart muscle becomes blocked, usually by a blood clot. Doctors unblock the artery and insert an expanding metal cage called a stent to keep it unblocked. This restores blood flow through the artery. Unfortunately, blood flow often does not return to smaller downstream blood vessels called capillaries. This can lead to further damage to the heart. Scientists have not been able to find a way to reliably open up those capillaries after a heart attack because it is not clear exactly what is keeping them closed. Muscle-like cells called pericytes, which wrap around the capillaries, are one possible culprit for the blockages. Pericytes narrow capillaries in the brain after stroke in animal experiments. These cells are also present on heart capillaries, but scientists do not know much about them. Now, O’Farrell, Mastitskaya, Hammond-Haley et al. show that pericytes are partly responsible for limiting blood flow in capillaries after a heart attack in rats. In the experiments, blood flow through an artery feeding the hearts of anaesthetized rats was restricted, simulating a heart attack. After the blood flow was later restored, 40% of the animal’s capillaries remained blocked. Many blockages occurred near pericytes that had narrowed the capillary preventing blood flow. Treating the rats with a drug called adenosine, which relaxes the pericytes, reduced capillary blockages and increased blood flow in the heart. Although adenosine could help to restore blood flow in the capillaries after a heart attack, it may also relax muscles around arteries and lower blood pressure, and so it may not be an ideal treatment. More studies are needed to determine whether drugs that target only the pericytes could complement existing heart attack treatments that unblock the arteries. If these studies are successful, pericyte-targeting drugs might prevent serious complications after a heart attack, including heart failure, heart rhythm abnormalities and future heart attacks.
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Affiliation(s)
- Fergus M O'Farrell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Svetlana Mastitskaya
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Matthew Hammond-Haley
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Felipe Freitas
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Wen Rui Wah
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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Mason McClatchey P, Bauer TA, Regensteiner JG, Schauer IE, Huebschmann AG, Reusch JEB. Dissociation of local and global skeletal muscle oxygen transport metrics in type 2 diabetes. J Diabetes Complications 2017; 31:1311-1317. [PMID: 28571935 PMCID: PMC5891220 DOI: 10.1016/j.jdiacomp.2017.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/05/2017] [Accepted: 05/08/2017] [Indexed: 01/28/2023]
Abstract
AIMS Exercise capacity is impaired in type 2 diabetes, and this impairment predicts excess morbidity and mortality. This defect appears to involve excess skeletal muscle deoxygenation, but the underlying mechanisms remain unclear. We hypothesized that reduced blood flow, reduced local recruitment of blood volume/hematocrit, or both contribute to excess skeletal muscle deoxygenation in type 2 diabetes. METHODS In patients with (n=23) and without (n=18) type 2 diabetes, we recorded maximal reactive hyperemic leg blood flow, peak oxygen utilization during cycling ergometer exercise (VO2peak), and near-infrared spectroscopy-derived measures of exercise-induced changes in skeletal muscle oxygenation and blood volume/hematocrit. RESULTS We observed a significant increase (p<0.05) in skeletal muscle deoxygenation in type 2 diabetes despite similar blood flow and recruitment of local blood volume/hematocrit. Within the control group skeletal muscle deoxygenation, local recruitment of microvascular blood volume/hematocrit, blood flow, and VO2peak are all mutually correlated. None of these correlations were preserved in type 2 diabetes. CONCLUSIONS These results suggest that in type 2 diabetes 1) skeletal muscle oxygenation is impaired, 2) this impairment may occur independently of bulk blood flow or local recruitment of blood volume/hematocrit, and 3) local and global metrics of oxygen transport are dissociated.
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Affiliation(s)
- P Mason McClatchey
- Division of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Department of Medicine, Denver Veterans Affairs Medical Center, Denver, CO, United States
| | - Timothy A Bauer
- Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Judith G Regensteiner
- Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Irene E Schauer
- Division of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Department of Medicine, Denver Veterans Affairs Medical Center, Denver, CO, United States
| | - Amy G Huebschmann
- Division of General Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Jane E B Reusch
- Division of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Department of Medicine, Denver Veterans Affairs Medical Center, Denver, CO, United States; Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.
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Hegelmaier T, Kumowski N, Mainka T, Vollert J, Goertz O, Lehnhardt M, Zahn P, Maier C, Kolbenschlag J. Remote ischaemic conditioning decreases blood flow and improves oxygen extraction in patients with early complex regional pain syndrome. Eur J Pain 2017; 21:1346-1354. [DOI: 10.1002/ejp.1033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2017] [Indexed: 12/17/2022]
Affiliation(s)
- T. Hegelmaier
- Department of Pain Medicine; BG University Hospital Bergmannsheil; Ruhr University; Bochum Germany
| | - N. Kumowski
- Department of Pain Medicine; BG University Hospital Bergmannsheil; Ruhr University; Bochum Germany
| | - T. Mainka
- Department of Pain Medicine; BG University Hospital Bergmannsheil; Ruhr University; Bochum Germany
- Department of Neurology; University Medical Center Hamburg Eppendorf; Germany
| | - J. Vollert
- Department of Pain Medicine; BG University Hospital Bergmannsheil; Ruhr University; Bochum Germany
- Center of Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim; Heidelberg University; Germany
| | - O. Goertz
- Department of Plastic and Hand Surgery, Burn Center; BG University Hospital Bergmannsheil, Ruhr University; Bochum Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery; Martin-Luther-Hospital; Berlin Germany
| | - M. Lehnhardt
- Department of Plastic and Hand Surgery, Burn Center; BG University Hospital Bergmannsheil, Ruhr University; Bochum Germany
| | - P.K. Zahn
- Department of Anesthesiology, Intensive and Palliative Care; BG University Hospital Bergmannsheil; Ruhr University; Bochum Germany
| | - C. Maier
- Department of Pain Medicine; BG University Hospital Bergmannsheil; Ruhr University; Bochum Germany
| | - J. Kolbenschlag
- Department of Plastic and Hand Surgery, Burn Center; BG University Hospital Bergmannsheil, Ruhr University; Bochum Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery; Martin-Luther-Hospital; Berlin Germany
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Venturi E, Pinnola S, Morizzo C, Boldrini B, Rossi M, Trifirò S, Tricò D, Natali A. Clinical Phenotype and Microvascular Dynamics of Subjects with Endothelial Dysfunction as Assessed by Peripheral Tonometry. Microcirculation 2016; 23:230-9. [PMID: 26800496 DOI: 10.1111/micc.12268] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/18/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To evaluate the characteristics and the determinants of ED, as measured by PAT. METHODS We measured basal and post-ischemic digital pulse amplitude (EndoPAT(®)) in a mixed outpatient population of 206 diabetic and 101 non-diabetic subjects, of whom 50% with clinically manifest CVD, undergoing to an extensive clinical, biochemical, and vascular phenotype characterization. RESULTS The major characteristics of ED (tertile 1 vs 3), in addition to lower post-ischemic vasodilatory reserve (34 vs 203%), were a 3-fold higher baseline pulse amplitude and a delayed (60 second) peak response. The main determinant of this response was the baseline pulse amplitude (Stβ = -0.59), which in turn was influenced by age (Stβ = 0.13), central obesity (Stβ = 0.27) and inversely by HDL cholesterol (Stβ = -0.17), and systolic blood pressure (Stβ = -0.19). No association was observed with cardiovascular risk factors, previous cardiovascular event or extent of atherosclerosis (ABI and IMT, PWV). Most of the variability in baseline pulse amplitude remained unexplained (r(2) = 0.14). CONCLUSIONS ED, as detected by PAT in a population enriched with subjects at risk for CVD neither reflects the burden of classical risk factors (under treatment) nor the severity of atherosclerosis. Aside from central obesity and HDL cholesterol, most of the factors responsible for this ED remain unknown.
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Affiliation(s)
- Elena Venturi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Silvia Pinnola
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Carmela Morizzo
- Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Pisa, Italy
| | - Beatrice Boldrini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Monica Rossi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Silvia Trifirò
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Domenico Tricò
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Andrea Natali
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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Liu H, Li G, Zhao W, Hu Y. Inhibition of MiR-92a May Protect Endothelial Cells After Acute Myocardial Infarction in Rats: Role of KLF2/4. Med Sci Monit 2016; 22:2451-62. [PMID: 27411964 PMCID: PMC4957625 DOI: 10.12659/msm.897266] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background This study was designed to investigate the effects of microRNA-92 (miR-92), Kruppel-like factor 2 (KLF2), and Kruppel-like factor 4 (KLF4) on endothelial injury after acute myocardial infarction (AMI). Material/Methods Blood samples were collected from 50 AMI patients for detection of cardiac troponin I (cTnI), heart-type fatty acid-binding protein (H-FABP), and von Willebrand factor (vWF). The Sprague-Dawley rat models of AMI (n=30) were established by ligating their left anterior descending coronary artery. The cardiac markers of AMI patients and rat models were analyzed with enzyme-linked immunosorbent assay and immunohistochemistry. Human umbilical vein endothelial cells were processed into 5 groups: control, negative control, miR-92a inhibitors, miR-92a inhibitors + KLF2 small interfering RNA (siRNA), and miR-92a inhibitors + KLF4 siRNA. Cell proliferation and apoptosis were detected using MTT assay and flow cytometry. RT-PCR and Western blot were conducted to analyze KLF2 and KLF4 expressions. Results AMI patients exhibited significantly higher expression of both endothelial injury markers (e.g., cTnI, H-FABP, vWF) and miR-92a in blood samples, when compared with controls (P<0.05). Model rats also had similar expressional tendencies, along with lower KLF2 and KLF4 expressions (P<0.05). Further, it could be observed in cellular experiments that treatment of miR-92a mimics can further upregulate endothelial injury markers, and miR-92a and both KLF2 and KLF4 were downregulated by miR-92a mimics (all, P<0.05). Also, the luciferase activity assay confirmed the direct binding of miR-92a to 3′ UTR of KLF2/4. Conclusions MiR-92a was involved in the endothelial injury process after AMI and was able to suppress KLF2 and KLF4 expression.
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Affiliation(s)
- Hongxia Liu
- Department of Clinical Laboratory Medicine, The Central Hospital of Nanyang, Nanyang, Henan, China (mainland)
| | - Guofen Li
- Cell Morphology Inspection of Clinical Laboratory Medicine, The Central Hospital of Nanyang, Nanyang, Henan, China (mainland)
| | - Wenxue Zhao
- Department of Cardiology, Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Yibo Hu
- Department of Cardiopulmonary Exercise Testing, The Central Hospital of Nanyang, Nanyang, Henan, China (mainland)
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Kunze KP, Rischpler C, Hayes C, Ibrahim T, Laugwitz KL, Haase A, Schwaiger M, Nekolla SG. Measurement of extracellular volume and transit time heterogeneity using contrast-enhanced myocardial perfusion MRI in patients after acute myocardial infarction. Magn Reson Med 2016; 77:2320-2330. [PMID: 27364875 DOI: 10.1002/mrm.26320] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 05/17/2016] [Accepted: 05/31/2016] [Indexed: 12/20/2022]
Abstract
PURPOSE To assess the ability of dynamic contrast-enhanced myocardial perfusion MRI to measure extracellular volume (ECV) and to investigate the possibility of estimating capillary transit time heterogeneity (CTH) in patients after myocardial infarction and successful revascularization. METHODS Twenty-four perfusion data sets were acquired on a 3 Tesla positron emission tomography (PET)/MRI scanner. Three perfusion models of different complexity were implemented in a hierarchical fashion with an Akaike information criterion being used to determine the number of fit parameters supported by the data. Results were compared sector-wise to ECV from an equilibrium T1 mapping method (modified look-locker inversion recovery (MOLLI)). RESULTS ECV derived from the perfusion analysis correlated well with equilibrium measurements (R² = 0.76). Estimation of CTH was supported in 16% of sectors (mostly remote). Inclusion of a nonzero CTH parameter usually led to lower estimates of first-pass extraction and slightly higher estimates of blood volume and flow. Estimation of the capillary permeability-surface area product was feasible in 81% of sectors. CONCLUSION Transit time heterogeneity has a measurable effect on the kinetic analysis of myocardial perfusion MRI data, and Gd-DTPA extravasation in the myocardium is usually not flow-limited in infarct-related pathology. Measurement of myocardial ECV using perfusion imaging could provide a scan-time efficient alternative to methods based on T1 mapping. Magn Reson Med 77:2320-2330, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Karl P Kunze
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany
| | - Christoph Rischpler
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
| | | | - Tareq Ibrahim
- DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany.,Klinikum rechts der Isar der TU München, Department of Cardiology, Munich, Germany
| | - Karl-Ludwig Laugwitz
- DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany.,Klinikum rechts der Isar der TU München, Department of Cardiology, Munich, Germany
| | - Axel Haase
- Zentralinstitut für Medizintechnik (IMETUM) der TU München, Garching, Germany
| | - Markus Schwaiger
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
| | - Stephan G Nekolla
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
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De Blasi RA, Romagnoli S, Rocco M. Bedside Assessment of the Microvascular Venous Compartment in Cardiac Surgery Patients With Valvular Diseases Undergoing Cardiopulmonary Bypass. J Cardiothorac Vasc Anesth 2016; 31:105-114. [PMID: 27546828 DOI: 10.1053/j.jvca.2016.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Blood volume reserve for venous return and the effects of cardiopulmonary bypass (CPB) on microvascular bed partitioning and blood flow were examined in patients with valvular diseases. DESIGN Prospective, consecutive, case-control study. SETTING Single university hospital. PARTICIPANTS The study comprised 20 adult cardiac surgery patients and 20 healthy volunteers. INTERVENTIONS Cardiovascular and microvascular variables were collected soon after the induction of anesthesia, after commencement of CPB, 20 minutes after separation from CPB, and in the intensive care unit. MEASUREMENTS AND MAIN RESULTS The unstressed and stressed volumes (Vu, Vs) and pressures therein (Pit, Ps) were measured in the brachioradial muscle with near-infrared spectroscopy, applying incremental venous occlusions. At the first time point, Vs and Pit showed lower and higher values, respectively, than those of control patients, but Vs increased with Vu during the study, whereas Pit remained unchanged. Fluid balance correlated with Pit (r = 0.83, p<0.001) and hemoglobin (r = 0.78, p = 0.004). A nonlinear regression was found between fluid balance and ΔVu (r = 0.90, p<0.001) [y = 1.85+37.43(-0.01×x)]. The Vu/Pit and Vs/Ps ratios were lower than those of the control patients. Blood flow correlated to Vs/Ps (r = 0.75, p<0.001). The time constant was lower than reference (p = 0.005) and increased 10 times after CPB. CONCLUSIONS Cardiac surgery patients have a limited blood volume reserve for venous return due to a reduced microvascular bed capacitance. This study demonstrated that during CPB a positive fluid balance induced an extravascular pressure increase and further reduced blood volume reserve.
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Affiliation(s)
- Roberto Alberto De Blasi
- Intensive Care Unit, Department of Medical and Surgical Science and Translational Medicine, Faculty of Medicine and Psychology, University of Rome "Sapienza," Roma, Italy.
| | - Stefano Romagnoli
- Intensive Care Unit, Department of Health Science, University of Florence, University Hospital Careggi, Florence, Italy
| | - Monica Rocco
- Intensive Care Unit, Department of Medical and Surgical Science and Translational Medicine, Faculty of Medicine and Psychology, University of Rome "Sapienza," Roma, Italy
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McClatchey PM, Schafer M, Hunter KS, Reusch JEB. The endothelial glycocalyx promotes homogenous blood flow distribution within the microvasculature. Am J Physiol Heart Circ Physiol 2016; 311:H168-76. [PMID: 27199117 DOI: 10.1152/ajpheart.00132.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/03/2016] [Indexed: 02/02/2023]
Abstract
Many common diseases involve impaired tissue perfusion, and heterogeneous distribution of blood flow in the microvasculature contributes to this pathology. The physiological mechanisms regulating homogeneity/heterogeneity of microvascular perfusion are presently unknown. Using established empirical formulations for blood viscosity modeling in vivo (blood vessels) and in vitro (glass tubes), we showed that the in vivo formulation predicts more homogenous perfusion of microvascular networks at the arteriolar and capillary levels. Next, we showed that the more homogeneous blood flow under simulated in vivo conditions can be explained by changes in red blood cell interactions with the vessel wall. Finally, we demonstrated that the presence of a space-filling, semipermeable layer (such as the endothelial glycocalyx) at the vessel wall can account for the changes of red blood cell interactions with the vessel wall that promote homogenous microvascular perfusion. Collectively, our results indicate that the mechanical properties of the endothelial glycocalyx promote homogeneous microvascular perfusion. Preservation or restoration of normal glycocalyx properties may be a viable strategy for improving tissue perfusion in a variety of diseases.
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Affiliation(s)
- P Mason McClatchey
- Division of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Medicine, Denver Veterans Affairs Medical Center, Denver, Colorado; Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Michal Schafer
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Division of Cardiology, Department of Pediatrics, Children's Hospital Colorado, Aurora, Colorado; and
| | - Kendall S Hunter
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Division of Cardiology, Department of Pediatrics, Children's Hospital Colorado, Aurora, Colorado; and
| | - Jane E B Reusch
- Division of Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Medicine, Denver Veterans Affairs Medical Center, Denver, Colorado; Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Center for Women's Health Research, University of Colorado School of Medicine, Aurora, Colorado
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Goltz D, Hittetiya K, Gevensleben H, Kirfel J, Diehl L, Meyer R, Büttner R. Loss of the LIM-only protein Fhl2 impairs inflammatory reaction and scar formation after cardiac ischemia leading to better hemodynamic performance. Life Sci 2016; 151:348-358. [DOI: 10.1016/j.lfs.2016.02.084] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/11/2016] [Accepted: 02/23/2016] [Indexed: 01/09/2023]
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Zhu G, Yao Y, Pan L, Zhu W, Yan S. Reduction of Leukocyte Counts by Hydroxyurea Improves Cardiac Function in Rats with Acute Myocardial Infarction. Med Sci Monit 2015; 21:3941-7. [PMID: 26675565 PMCID: PMC4687945 DOI: 10.12659/msm.893744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND This study aimed to decrease leukocytes counts by hydroxyurea (Hu) in an acute myocardial infarction (AMI) rat model and examine its effect on the inflammatory response of myocardial infarction and cardiac functions. MATERIAL AND METHODS AMI was successfully caused in 36 rats, and 12 control rats received sham operation. Rats in the AMI group were then randomly divided into Hu and vehicle group with 18 rats each. Rats in the Hu AMI group received Hu (200 mg/kg) intragastrically while vehicle AMI group received saline. Leukocytes counts, cardiac functions, myocardial tissue morphology, and levels of soluble intercellular adhesion molecule-1 (sICAM), P-selectin and platelet activating factor (PAF) were measured and compared among the three groups four weeks after AMI induction. RESULTS Leukocytes, neutrophils, and leukomonocyte counts in vehicle AMI rats were significantly higher than that of the normal control group (p<0.05). However, Hu treatment decreased their counts significantly (p<0.05). sICAM, P-selectin, and PAF level in vehicle AMI group were significantly higher than those of the normal group, and their level was also decreased by Hu treatment (p<0.05). Echocardiography analysis showed that Hu treatment increased left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) compared to that of vehicle AMI group (p<0.05). Histopathological examination showed that Hu significantly reduced the swelling of the heart muscle fiber in necrotic foci and the number of inflammatory cells infiltrated into myocardial interstitium compared to vehicle AMI group. CONCLUSIONS Decrease leukocytes counts by Hu significantly reduced inflammatory reaction and improved cardiac functions in AMI rats.
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Affiliation(s)
- Guiyue Zhu
- Department of Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Ji'nan, Shandong, China (mainland)
| | - Yucai Yao
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Ji'nan, Shandong, China (mainland)
| | - Lingyun Pan
- Department of Emergency Medicine, Second People's Hospital of Liaocheng, Linqing, Shandong, China (mainland)
| | - Wei Zhu
- Institute of Radiation Medicine, Shandong Academy of Medical Sciences, Ji'nan, Shandong, China (mainland)
| | - Suhua Yan
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Ji'nan, Shandong, China (mainland)
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Østergaard L, Granfeldt A, Secher N, Tietze A, Iversen NK, Jensen MS, Andersen KK, Nagenthiraja K, Gutiérrez‐Lizardi P, Mouridsen K, Jespersen SN, Tønnesen EK. Microcirculatory dysfunction and tissue oxygenation in critical illness. Acta Anaesthesiol Scand 2015; 59:1246-59. [PMID: 26149711 PMCID: PMC4758388 DOI: 10.1111/aas.12581] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/19/2015] [Accepted: 06/14/2015] [Indexed: 12/19/2022]
Abstract
Severe sepsis is defined by organ failure, often of the kidneys, heart, and brain. It has been proposed that inadequate delivery of oxygen, or insufficient extraction of oxygen in tissue, may explain organ failure. Despite adequate maintenance of systemic oxygen delivery in septic patients, their morbidity and mortality remain high. The assumption that tissue oxygenation can be preserved by maintaining its blood supply follows from physiological models that only apply to tissue with uniformly perfused capillaries. In sepsis, the microcirculation is profoundly disturbed, and the blood supply of individual organs may therefore no longer reflect their access to oxygen. We review how capillary flow patterns affect oxygen extraction efficacy in tissue, and how the regulation of tissue blood flow must be adjusted to meet the metabolic needs of the tissue as capillary flows become disturbed as observed in critical illness. Using the brain, heart, and kidney as examples, we discuss whether disturbed capillary flow patterns might explain the apparent mismatch between organ blood flow and organ function in sepsis. Finally, we discuss diagnostic means of detecting capillary flow disturbance in animal models and in critically ill patients, and address therapeutic strategies that might improve tissue oxygenation by modifying capillary flow patterns.
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Affiliation(s)
- L. Østergaard
- Department of Neuroradiology Aarhus University Hospital Aarhus Denmark
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - A. Granfeldt
- Department of Anaesthesia and Intensive Care Medicine Aarhus University Hospital Aarhus Denmark
| | - N. Secher
- Department of Anaesthesia and Intensive Care Medicine Aarhus University Hospital Aarhus Denmark
| | - A. Tietze
- Department of Neuroradiology Aarhus University Hospital Aarhus Denmark
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - N. K. Iversen
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - M. S. Jensen
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - K. K. Andersen
- Department of Anaesthesia and Intensive Care Medicine Aarhus University Hospital Aarhus Denmark
| | - K. Nagenthiraja
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - P. Gutiérrez‐Lizardi
- Faculty of Dentistry University of Monterrey Monterrey Mexico
- Critical Care College of Nuevo León Monterrey Mexico
| | - K. Mouridsen
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - S. N. Jespersen
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
- Department of Physics and Astronomy Aarhus University Aarhus Denmark
| | - E. K. Tønnesen
- Department of Anaesthesia and Intensive Care Medicine Aarhus University Hospital Aarhus Denmark
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Jordan JE, Pereira BD, Lane MR, Morykwas MJ, McGee M, Argenta LC. Mechanical tissue resuscitation (MTR): a nonpharmacological approach to treatment of acute myocardial infarction. J Card Surg 2015; 30:659-67. [PMID: 26040506 DOI: 10.1111/jocs.12580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND AIM Myocardial ischemia-reperfusion injury is known to trigger an inflammatory response involving edema, apoptosis, and neutrophil activation/accumulation. Recently, mechanical tissue resuscitation (MTR) was described as a potent cardioprotective strategy for reduction of myocardial ischemia-reperfusion injury. Here, we further describe the protective actions of MTR and begin to define its therapeutic window. METHODS A left ventricular, free-wall ischemic area was created in anesthetized swine for 85 minutes and then reperfused for three hours. Animals were randomized to two groups: (1) untreated controls (Control) and (2) application of MTR that was delayed 90 minutes after the initiation of reperfusion (D90). Hemodynamics and regional myocardial blood flow were assessed at multiple time points. Infarct size and neutrophil accumulation were assessed following the reperfusion period. In separate cohorts, the effect of MTR on myocardial interstitial water (MRI imaging) and blood flow was examined. RESULTS Both groups had similar areas at risk (AAR), hemodynamics, and arterial blood gas values. MTR, even when delayed 90 minutes into reperfusion (D90, 29.2 ± 5.0% of AAR), reduced infarct size significantly compared to Controls (51.9 ± 2.7%, p = 0.006). This protection was associated with a 33% decrease in neutrophil accumulation (p = 0.047). Improvements in blood flow and interstitial water were also observed. Moreover, we demonstrated that the therapeutic window for MTR lasts for at least 90 minutes following reperfusion. CONCLUSIONS This study confirms our previous observations that MTR is an effective therapeutic approach to reducing reperfusion injury with a clinically useful treatment window.
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Affiliation(s)
- James E Jordan
- Department of Cardiothoracic Surgery, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Beatriz D Pereira
- Department of Cardiothoracic Surgery, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Magan R Lane
- Department of Cardiothoracic Surgery, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Michael J Morykwas
- Department of Plastic & Reconstructive Surgery, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Maria McGee
- Department of Plastic & Reconstructive Surgery, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Louis C Argenta
- Department of Plastic & Reconstructive Surgery, Wake Forest School of Medicine, Winston-Salem, North Carolina
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Østergaard L, Jespersen SN, Engedahl T, Gutiérrez Jiménez E, Ashkanian M, Hansen MB, Eskildsen S, Mouridsen K. Capillary dysfunction: its detection and causative role in dementias and stroke. Curr Neurol Neurosci Rep 2015; 15:37. [PMID: 25956993 PMCID: PMC4441906 DOI: 10.1007/s11910-015-0557-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In acute ischemic stroke, critical hypoperfusion is a frequent cause of hypoxic tissue injury: As cerebral blood flow (CBF) falls below the ischemic threshold of 20 mL/100 mL/min, neurological symptoms develop and hypoxic tissue injury evolves within minutes or hours unless the oxygen supply is restored. But is ischemia the only hemodynamic source of hypoxic tissue injury? Reanalyses of the equations we traditionally use to describe the relation between CBF and tissue oxygenation suggest that capillary flow patterns are crucial for the efficient extraction of oxygen: without close capillary flow control, "functional shunts" tend to form and some of the blood's oxygen content in effect becomes inaccessible to tissue. This phenomenon raises several questions: Are there in fact two hemodynamic causes of tissue hypoxia: Limited blood supply (ischemia) and limited oxygen extraction due to capillary dysfunction? If so, how do we distinguish the two, experimentally and in patients? Do flow-metabolism coupling mechanisms adjust CBF to optimize tissue oxygenation when capillary dysfunction impairs oxygen extraction downstream? Cardiovascular risk factors such as age, hypertension, diabetes, hypercholesterolemia, and smoking increase the risk of both stroke and dementia. The capillary dysfunction phenomenon therefore forces us to consider whether changes in capillary morphology or blood rheology may play a role in the etiology of some stroke subtypes and in Alzheimer's disease. Here, we discuss whether certain disease characteristics suggest capillary dysfunction rather than primary flow-limiting vascular pathology and how capillary dysfunction may be imaged and managed.
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Affiliation(s)
- Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark,
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Sialyltransferase7A, a Klf4-responsive gene, promotes cardiomyocyte apoptosis during myocardial infarction. Basic Res Cardiol 2015; 110:28. [PMID: 25860962 DOI: 10.1007/s00395-015-0484-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 03/15/2015] [Accepted: 03/31/2015] [Indexed: 01/01/2023]
Abstract
Myocardial infarction (MI) is one major cause of heart failure through its induction of cardiomyocyte death. However, the molecular mechanisms associated with MI-induced cardiomyocyte apoptosis in the context of sialylation of heart are not yet understood. In this study, we found that sialyltransferase7A (Siat7A), one of the members of sialyltransferase family, was significantly increased in the ischemic myocardium, as well as in the human cardiomyocyte cell line AC16 under hypoxic condition. The Sialyl-Tn antigen (Neu5Acα2-6GalNAc-O-Ser/Thr) synthesized by Siat7A also increased in the AC16 cardiomyocytes following hypoxic stimulus. Increased Siat7A promoted cardiomyocyte apoptosis. The knockdown of Siat7A expression reduced cardiomyocyte apoptosis in both of vivo and vitro. Furthermore, the decreased extracellular signal-regulated kinase ERK1 and ERK2 (ERK1/2) activity was involved in the Siat7A-induced cardiomyocyte apoptosis. Notably, we showed that Krüppel-like factor 4 (Klf4), one of the transcription factors, specifically bound to the Siat7A promoter by ChIP assays. Deletion and mutagenesis analysis identified that Klf4 could transactivate the Siat7A promoter region (nt -655 to -636 bp). The upregulated Siat7A expression, which was paralleled by the increased Klf4 in the ischemic myocardium, contributed to cardiomyocyte apoptosis. Our study suggests Siat7A could be a valuable target for developing treatments for MI patients.
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