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Namani R, Lee LC, Lanir Y, Kaimovitz B, Shavik SM, Kassab GS. Effects of myocardial function and systemic circulation on regional coronary perfusion. J Appl Physiol (1985) 2020; 128:1106-1122. [PMID: 32078466 DOI: 10.1152/japplphysiol.00450.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cardiac-coronary interaction and the effects of its pathophysiological variations on spatial heterogeneity of coronary perfusion and myocardial work are still poorly understood. This hypothesis-generating study predicts spatial heterogeneities in both regional cardiac work and perfusion that offer a new paradigm on the vulnerability of the subendocardium to ischemia, particularly at the apex. We propose a mathematical and computational modeling framework to simulate the interaction of left ventricular mechanics, systemic circulation, and coronary microcirculation. The computational simulations revealed that the relaxation rate of the myocardium has a significant effect whereas the contractility has a marginal effect on both the magnitude and transmural distribution of coronary perfusion. The ratio of subendocardial to subepicardial perfusion density (Qendo/Qepi) changed by -12 to +6% from a baseline value of 1.16 when myocardial contractility was varied by +25 and -10%, respectively; Qendo/Qepi changed by 37% when sarcomere relaxation rate, b, was faster and increased by 10% from the baseline value. The model predicts axial differences in regional myocardial work and perfusion density across the wall thickness. Regional myofiber work done at the apex is 30-50% lower than at the center region, whereas perfusion density in the apex is lower by only 18% compared with the center. There are large axial differences in coronary flow and myocardial work at the subendocardial locations, with the highest differences located at the apex region. A mismatch exists between perfusion density and regional work done at the subendocardium. This mismatch is speculated to be compensated by coronary autoregulation.NEW & NOTEWORTHY We present a model of left ventricle perfusion based on an anatomically realistic coronary tree structure that includes its interaction with the systemic circulation. Left ventricular relaxation rate has a significant effect on the regional distribution of coronary flow and myocardial work.
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Affiliation(s)
- Ravi Namani
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan
| | - Lik C Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan
| | - Yoram Lanir
- Faculty of Biomedical Engineering, Technion, Israel Institute of Technology, Haifa, Israel
| | - Benjamin Kaimovitz
- Faculty of Biomedical Engineering, Technion, Israel Institute of Technology, Haifa, Israel
| | - Sheikh M Shavik
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan
| | - Ghassan S Kassab
- The California Medical Innovations Institute Inc., San Diego, California
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Braun T, Spiliopoulos S, Veltman C, Hergesell V, Passow A, Tenderich G, Borggrefe M, Koerner MM. Detection of myocardial ischemia due to clinically asymptomatic coronary artery stenosis at rest using supervised artificial intelligence-enabled vectorcardiography - A five-fold cross validation of accuracy. J Electrocardiol 2020; 59:100-105. [PMID: 32036110 DOI: 10.1016/j.jelectrocard.2019.12.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/16/2019] [Accepted: 12/31/2019] [Indexed: 11/16/2022]
Abstract
BACKGROUND Coronary artery disease (CAD) is a leading cause of death and disability. Conventional non-invasive diagnostic modalities for the detection of stable CAD at rest are subject to significant limitations: low sensitivity, and personal expertise. We aimed to develop a reliable and time-cost efficient screening tool for the detection of coronary ischemia using machine learning. METHODS We developed a supervised artificial intelligence algorithm combined with a five lead vectorcardiography (VCG) approach (i.e. Cardisiography, CSG) for the diagnosis of CAD. Using vectorcardiography, the excitation process of the heart can be described as a three-dimensional signal. A diagnosis can be received, by first, calculating specific physical parameters from the signal, and subsequently, analyzing them with a machine learning algorithm containing neuronal networks. In this multi-center analysis, the primary evaluated outcome was the accuracy of the CSG Diagnosis System, validated by a five-fold nested cross-validation in comparison to angiographic findings as the gold standard. Individuals with 1, 2, or 3- vessel disease were defined as being affected. RESULTS Of the 595 patients, 62·0% (n = 369) had 1, 2 or 3- vessel disease identified by coronary angiography. CSG identified a CAD at rest with a sensitivity of 90·2 ± 4·2% for female patients (male: 97·2 ± 3·1%), specificity of 74·4 ± 9·8% (male: 76·1 ± 8·5%), and overall accuracy of 82·5 ± 6·4% (male: 90·7 ± 3·3%). CONCLUSION These findings demonstrate that supervised artificial intelligence-enabled vectorcardiography can overcome limitations of conventional non-invasive diagnostic modalities for the detection of coronary ischemia at rest and is capable as a highly valid screening tool.
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Affiliation(s)
- Till Braun
- Cardisio GmbH, The Squaire 12, D-60549 Frankfurt am Main, Germany
| | - Sotirios Spiliopoulos
- Department of Cardiac Surgery, University Heart Center Graz, Medical University Graz, Auenbruggerplatz 29, A-8036 Graz, Austria
| | | | - Vera Hergesell
- Department of Cardiac Surgery, University Heart Center Graz, Medical University Graz, Auenbruggerplatz 29, A-8036 Graz, Austria
| | - Alexander Passow
- Cardisio GmbH, The Squaire 12, D-60549 Frankfurt am Main, Germany; Faculty of Medicine, University Bochum, Universitaetsstrasse 150, D-44801 Bochum, Germany
| | - Gero Tenderich
- Cardisio GmbH, The Squaire 12, D-60549 Frankfurt am Main, Germany; Faculty of Medicine, University Bochum, Universitaetsstrasse 150, D-44801 Bochum, Germany
| | - Martin Borggrefe
- First Department of Medicine, University Medical Centre Mannheim (UMM), Faculty of Medicine Mannheim, University of Heidelberg, European Center for AngioScience (ECAS), and DZHK (German Center for Cardiovascular Research) partner site Heidelberg/Mannheim, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany
| | - Michael M Koerner
- Nazih Zuhdi Advanced Cardiac Care & Transplant Institute, Department of Medicine, Integris Baptist Medical Center, 3400 NW Expressway, Bldg C, Suite 300, Oklahoma City, OK 73162, USA; Department of Rural Health - Medicine/Cardiology, Oklahoma State University Center For Health Sciences, 1111 W 17(th) Street, Tulsa, OK 74107, USA.
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Zhang P, Fassett JT, Zhu G, Li J, Hu X, Xu X, Chen Y, Bache RJ. Repetitive ischemia increases myocardial dimethylarginine dimethylaminohydrolase 1 expression. Vasc Med 2017; 22:179-188. [PMID: 28145161 DOI: 10.1177/1358863x16681215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Pharmacologic inhibition of nitric oxide production inhibits growth of coronary collateral vessels. Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is the major enzyme that degrades asymmetric dimethylarginine (ADMA), a potent inhibitor of nitric oxide synthase. Here we examined regulation of the ADMA-DDAH1 pathway in a canine model of recurrent myocardial ischemia during the time when coronary collateral growth is known to occur. Under basal conditions, DDAH1 expression was non-uniform across the left ventricular (LV) wall, with expression strongest in the subepicardium. In response to ischemia, DDAH1 expression was up-regulated in the midmyocardium of the ischemic zone, and this was associated with a significant reduction in myocardial interstitial fluid (MIF) ADMA. The decrease in MIF ADMA during ischemia was likely due to increased DDAH1 because myocardial protein arginine N-methyl transferase 1 (PRMT1) and the methylated arginine protein content (the source of ADMA) were unchanged or increased, respectively, at this time. The inflammatory mediators interleukin (IL-1β) and tumor necrosis factor (TNF-α) were also elevated in the midmyocardium where DDAH1 expression was increased. Both of these factors significantly up-regulated DDAH1 expression in cultured human coronary artery endothelial cells. Taken together, these results suggest that inflammatory factors expressed in response to myocardial ischemia contributed to up-regulation of DDAH1, which was responsible for the decrease in MIF ADMA.
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Affiliation(s)
- Ping Zhang
- 1 Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA
| | - John T Fassett
- 2 Department of Pharmacology and Toxicology, Karl Franzen University of Graz, Graz, Austria
| | - Guangshuo Zhu
- 1 Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Jingxin Li
- 3 Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xinli Hu
- 4 Institute of Molecular Medicine, Peking University, Beijing, China
| | - Xin Xu
- 1 Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Yingjie Chen
- 1 Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Robert J Bache
- 1 Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA
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Davids M, Richir MC, Visser M, Ellger B, van den Berghe G, van Leeuwen PAM, Teerlink T. Role of dimethylarginine dimethylaminohydrolase activity in regulation of tissue and plasma concentrations of asymmetric dimethylarginine in an animal model of prolonged critical illness. Metabolism 2012; 61:482-90. [PMID: 22000584 DOI: 10.1016/j.metabol.2011.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/16/2011] [Accepted: 08/18/2011] [Indexed: 12/26/2022]
Abstract
High plasma concentrations of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, are associated with adverse outcome in critically ill patients. Asymmetric dimethylarginine is released within cells during proteolysis of methylated proteins and is either degraded by dimethylarginine dimethylaminohydrolase (DDAH) or exported to the circulation via cationic amino acid transporters. We aimed to establish the role of DDAH activity in the regulation of tissue and plasma concentrations of ADMA. In 33 critically ill rabbits, we measured DDAH activity in kidney, liver, heart, and skeletal muscle and related these values to concentrations of ADMA in these tissues and in the circulation. Both DDAH activity and ADMA concentration were highest in kidney and lowest in skeletal muscle, with intermediate values for liver and heart. Whereas ADMA content was significantly correlated between tissues (r = 0.40-0.78), DDAH activity was not. Significant inverse associations between DDAH activity and ADMA content were only observed in heart and liver. Plasma ADMA was significantly associated with ADMA in the liver (r = 0.41), but not in the other tissues. In a multivariable regression model, DDAH activities in muscle, kidney, and liver, but not in heart, were negatively associated with plasma ADMA concentration, together explaining approximately 50% of its variation. In critical illness, plasma ADMA poorly reflects intracellular ADMA. Furthermore, tissue DDAH activity is a stronger predictor of plasma ADMA than of intracellular ADMA, indicating that, compared with DDAH activity, generation of ADMA and cationic amino acid transporter-mediated exchange may be more important regulators of intracellular ADMA.
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Affiliation(s)
- Mariska Davids
- Metabolic Laboratory, Department of Clinical Chemistry, VU University Medical Center, PO Box 7057, 1007MB Amsterdam, The Netherlands
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TACHIBANA HIROYUKI, MATSUMOTO TAKESHI, OGASAWARA YASUO, KODAMA TAKAO, KAJIYA FUMIHIKO. QUANTITATIVE DOUBLE-TRACER DIGITALRADIOGRAPHY BASED ON DESMETHYLIMIPRAMINE DEPOSITION: APPLICATION TO STUDIES ON MYOCARDIAL PERFUSION HETEROGENEITY. J MECH MED BIOL 2011. [DOI: 10.1142/s0219519403000776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Desmethylimipramine (DMI), an α2-adrenergic antagonist, is a nearly ideal deposition tracer for evaluating the myocardial flow distribution with the least artifactual effects on microcirculation. Myocardial retentions of tritium- and iodine-125-labeled DMI (HDMI, IDMI) were confirmed to be satisfactory; the retentions of IDMI and HDMI at 1 min were 95 and 91% respectively in isolated Tyrode-perfused rabbit hearts (n=6) at a perfusion rate of 8.1 ml/min/g, and 98 and 96% respectively, in blood-perfused rat hearts (n=4) at a perfusion rate of 3.1 ml/min/g. Using these tracers combined with subtraction digitalradiography, it allowed the assessing of changes of myocardial flow distribution with 400×400 μ m 2 resolution. In blood-perfused rat hearts (n=4), the validity of this method was verified by the strong cross-correlation between regional densities of two tracers injected simultaneously (r=0.94) and the regression line having a slope close to one. Furthermore, in Tyrode-perfused rabbit hearts, the flow distributions were evaluated before and after decreasing perfusion rate moderately by 34% (n=7) and severely by 70% (n=7). Severe flow reduction increased the coefficient of variation of tracer density (CV) significantly from 19 to 25%, but CV did not change with moderate flow reduction (20 vs. 19%). Regional densities of two tracers were cross-correlated still substantially under severe low-flow perfusion (r=0.84). Accordingly, flow differences between originally high- and low-flow regions were enlarged under severe flow reduction. In conclusion, double-tracer digitalradiography based on the DMI deposition will be a potent method for the analysis of flow heterogeneity at microvascular levels.
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Affiliation(s)
- HIROYUKI TACHIBANA
- Department of Medical Engineering, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - TAKESHI MATSUMOTO
- Department of Medical Engineering, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - YASUO OGASAWARA
- Department of Medical Engineering, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - TAKAO KODAMA
- Department of Biochemical Engineering and Science, Kyushu Institute of Technology, Iizuka, 820-8502, Japan
| | - FUMIHIKO KAJIYA
- Department of Medical Engineering, Kawasaki Medical School, Kurashiki, 701-0192, Japan
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine and Dentistry, Okayama, 700-8558, Japan
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Gray GA, Patrizio M, Sherry L, Miller AA, Malaki M, Wallace AF, Leiper JM, Vallance P. Immunolocalisation and activity of DDAH I and II in the heart and modification post-myocardial infarction. Acta Histochem 2010; 112:413-23. [PMID: 19481782 DOI: 10.1016/j.acthis.2009.02.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2008] [Revised: 02/01/2009] [Accepted: 02/04/2009] [Indexed: 11/15/2022]
Abstract
Asymmetric dimethylarginine (ADMA) and N(G) monomethyl-L-arginine (L-NMMA) are endogenous inhibitors of nitric oxide synthases (NOS) and their local concentration is determined by the activity of dimethylarginine dimethylaminohydrolases (DDAHs). The current study in male Wistar rats was designed to immunolocalise DDAH I and II in relation to NOS and to investigate changes in distribution, activity and ADMA content in the acute period following myocardial infarction (MI) resulting from coronary artery ligation. Seven days after the coronary artery ligation, L-Arg and methylated arginine content, as well as DDAH activity were determined in homogenates of left ventricular (LV) infarct and border. The distribution of immunoreactive DDAH I, DDAH II, eNOS and iNOS were determined in sections of LV. In healthy hearts, DDAH I was absent, however, DDAH II was localized to endothelium and endocardium with a similar distribution to that of eNOS. Following MI, LV DDAH activity was increased (to 210+/-19% of control, P<0.05). Both DDAH I and DDAH II proteins were detected in peri-infarct cardiomyocytes, while DDAH II immunoreactivity was additionally localized to infiltrating inflammatory cells and blood vessels in the healing infarct. Both plasma and LV concentrations of the DDAH substrate, ADMA, were increased post-MI, although the ratio of Arg:ADMA was retained in the LV post-MI relative to sham operated controls. In conclusion, DDAH II has a distribution similar to eNOS in healthy myocardium. The increased levels and activity of DDAH I and DDAH II enzymes following myocardial infarction suggest a potential role for them in local protection of NOS enzymes from inhibition by methylated arginines during infarct healing.
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Affiliation(s)
- Gillian A Gray
- Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
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Zuurbier CJ, Van Wezel HB. Glucose-insulin therapy, plasma substrate levels and cardiac recovery after cardiac ischemic events. Cardiovasc Drugs Ther 2008; 22:125-31. [PMID: 18266096 PMCID: PMC2329728 DOI: 10.1007/s10557-008-6087-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Accepted: 01/17/2008] [Indexed: 01/04/2023]
Abstract
Introduction The potential usefulness of glucose-insulin therapy relies to a large extent on the premise that it prevents hyperglycemia and hyperlipidemia following cardiac ischemic events. Methods In this review we evaluate the literature concerning plasma glucose and free fatty acids levels during and following cardiac ischemic events. Results The data indicate that hyperlipidemia and hyperglycemia most likely occur during acute coronary ischemic syndromes in the conscious state (e.g. acute myocardial infarction) and less so during reperfusion following CABG reperfusion. This is in accordance with observations that glucose-insulin therapy during early reperfusion post CABG may actually cause hypolipidemia, because substantial hyperlipidemia does not appear to occur during that stage of cardiac surgery. Discussion Considering recent data indicating that hypolipidemia may be detrimental for cardiac function, we propose that free fatty acid levels during reperfusion post CABG with the adjunct glucose-insulin therapy need to be closely monitored. Conclusion From a clinical point of view, a strategy directed at monitoring and thereafter maintaining plasma substrate levels in the normal range for both glucose (4–6 mM) and FFA (0.2–0.6 mM) as well as stimulation of glucose oxidation, promises to be the most optimal metabolic reperfusion treatment following cardiac ischemic episodes. Future (preclinical and subsequently clinical) investigations are required to investigate whether the combination of glucose-insulin therapy with concomitant lipid administration may be beneficial in the setting of reperfusion post CABG.
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Affiliation(s)
- C J Zuurbier
- Department of Anesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Liver proteomics for therapeutic drug discovery: inhibition of the cyclophilin receptor CD147 attenuates sepsis-induced acute renal failure. Crit Care Med 2007; 35:2319-28. [PMID: 17944020 DOI: 10.1097/01.ccm.0000281858.44387.a2] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Sepsis-induced multi-organ failure continues to have a high mortality. The liver is an organ central to the disease pathogenesis. The objective of this study was to identify the liver proteins that change in abundance with sepsis and subsequently identify new drug targets. DESIGN Proteomic discovery study and drug target validation. For the proteomics study, three biological replicate mice were used per group. SETTING Research institute laboratory. SUBJECTS Three-month-old C57BL/6 mice. INTERVENTIONS We used a mouse model of sepsis based on cecal ligation and puncture, but with fluid and antibiotic resuscitation. Liver proteins that changed in abundance were identified by difference in gel electrophoresis. We compared liver proteins from 6-hr post-cecal ligation and puncture to sham-operated mice ("early proteins") and 24-hr post-cecal ligation and puncture with 6-hr post-cecal ligation and puncture ("late proteins"). Proteins that changed in abundance were identified by tandem mass spectrometry. We then inhibited the receptor for one protein and determined the effect on sepsis-induced organ dysfunction. RESULTS The liver proteins that changed in abundance after sepsis had a range of functions such as acute phase response, coagulation, endoplasmic reticulum stress, oxidative stress, apoptosis, mitochondrial electron transfer proteins, and nitric oxide metabolism. We found that cyclophilin increased in abundance after cecal ligation and puncture. When the receptor for this protein, CD147, was inhibited, sepsis-induced renal dysfunction was reduced. There was also a significant reduction in serum cytokine production when CD147 was inhibited. CONCLUSION By applying proteomics to a clinically relevant mouse model of sepsis, we identified a number of novel proteins that changed in abundance. The inhibition of the receptor for one of these proteins, cyclophilin, attenuated sepsis-induced acute renal failure. The application of proteomics to sepsis research can facilitate the discovery of new therapeutic targets.
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Matsumoto T, Asano T, Takemoto M, Tachibana H, Ogasawara Y, Kajiya F. Microheterogeneity of regional myocardial blood flows in low-perfused rat hearts evaluated by double-tracer digital radiography. Appl Radiat Isot 2007; 65:910-7. [PMID: 17574429 DOI: 10.1016/j.apradiso.2007.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2005] [Revised: 03/14/2007] [Accepted: 03/14/2007] [Indexed: 10/23/2022]
Abstract
Using (3)H- and (125)I-labeled desmethylimipramine (DMI) for regional flow tracers, we established a two-time measurement method for the spatial pattern of myocardial perfusion in cross-circulated rat hearts. Myocardial extractions and retentions of these tracers were confirmed to be satisfactory; however, the latter were less than 90% after 3 min at a perfusion rate of 2.9 ml/min/g, limiting the present application to a short-time perfusion measurement. Distributions of myocardial depositions were separated by subtraction digital radiography with 400-microm pixel resolution. Its feasibility was examined by regression analysis between local deposition densities of (3)H- and (125)I-DMI injected simultaneously. The slope, y-intercept, and correlation coefficient (r) of the regression line were 0.98+/-0.04, 0.02+/-0.04, and 0.95+/-0.03, respectively, indicating the validity of the present image subtraction technique. The spatial pattern of myocardial perfusion in response to flow reduction was evaluated by the injections of (3)H- and (125)I-DMI, respectively, before and after a nearly 70% flow reduction. A significant correlation between normalized density distributions of these tracers was found in both subepicardium (r=0.77+/-0.12) and subendocardium (r=0.73+/-0.20), indicating the stable pattern of myocardial perfusion. However, the coefficient of variation of tracer densities showed a decrease of subendocardial flow heterogeneity from 35+/-15% to 31+/-16%. Thus, flow differences between originally high- and low-flow regions in subendocardium were reduced on a relative basis during low perfusion.
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Affiliation(s)
- Takeshi Matsumoto
- Bioengineering Division, Osaka University Graduate School of Engineering Science, Machikaneyamacho 13, Toyonaka 5608531, Japan.
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Henninger N, Feldmann RE, Fütterer CD, Schrempp C, Maurer MH, Waschke KF, Kuschinsky W, Schwab S. Spatial learning induces predominant downregulation of cytosolic proteins in the rat hippocampus. GENES BRAIN AND BEHAVIOR 2007; 6:128-40. [PMID: 16643511 DOI: 10.1111/j.1601-183x.2006.00239.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spatial learning is known to depend on protein synthesis in the hippocampus. Whereas the role of the hippocampus in spatial memory is established, the biochemical and molecular mechanisms underlying this process are poorly understood. To comprehend the complex pattern of protein expression induced by spatial learning, we analyzed alterations in the rat hippocampus proteome after 7 days of spatial learning in the Morris water maze. Forty Wistar rats were randomized into two groups. Animals of group A learned to localize a hidden platform in the water maze. Animals of group B served as controls and spent exactly the same time in the water maze as animals of group A. However, no platform was used in this test and the rats could not learn to localize the target. After the last trial, hydrophilic proteins from the hippocampus were isolated. A proteome-wide study was performed, based on two-dimensional gel electrophoresis and mass spectrometry. Compared with non-learning animals, 53 (70%) proteins were downregulated and 23 (30%) proteins were upregulated after 7 days in rats with spatial learning. The overall changes in protein expression, as quantified by the induction factor, ranged from -1.62 (downregulation to 62%) to 2.10 (upregulation by 110%) compared with controls (100%). Most identified proteins exhibit known functions in vesicle transport, cytoskeletal architecture, and metabolism as well as neurogenesis. These findings indicate that learning in the Morris water maze has a morphological correlate on the proteome level in the hippocampus.
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Affiliation(s)
- N Henninger
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA.
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11
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Siroen MPC, Teerlink T, Nijveldt RJ, Prins HA, Richir MC, van Leeuwen PAM. The Clinical Significance of Asymmetric Dimethylarginine. Annu Rev Nutr 2006; 26:203-28. [PMID: 16848705 DOI: 10.1146/annurev.nutr.26.061505.111320] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In 1992, asymmetrical dimethylarginine (ADMA) was first described as an endogenous inhibitor of the arginine-nitric oxide (NO) pathway. From then, its role in regulating NO production has attracted increasing attention. Nowadays, ADMA is regarded as a novel cardiovascular risk factor. The role of the kidney and the liver in the metabolism of ADMA has been extensively studied and both organs have proven to play a key role in the elimination of ADMA. Although the liver removes ADMA exclusively via degradation by the enzyme dimethylarginine dimethylaminohydrolase (DDAH), the kidney uses both metabolic degradation via DDAH and urinary excretion to eliminate ADMA. Modulating activity and/or expression of DDAH is still under research and may be a potential therapeutic approach to influence ADMA plasma levels. Interestingly, next to its association with cardiovascular disease, ADMA also seems to play a role in other clinical conditions, such as critical illness, hepatic failure, and preeclampsia. To elucidate the clinical significance of ADMA in these conditions, the field of research must be enlarged.
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Affiliation(s)
- Michiel P C Siroen
- Department of Surgery, VU University Medical Center, Amsterdam, The Netherlands.
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Knipp M. How to Control NO Production in Cells: Nω,Nω-Dimethyl-L-Arginine Dimethylaminohydrolase as a Novel Drug Target. Chembiochem 2006; 7:879-89. [PMID: 16680784 DOI: 10.1002/cbic.200500527] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Markus Knipp
- Department of Chemistry, University of Arizona, 1306 East University Boulevard, Tucson, AZ 85721-0041, USA.
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Kalenka A, Maurer MH, Feldmann RE, Kuschinsky W, Waschke KF. Volatile anesthetics evoke prolonged changes in the proteome of the left ventricule myocardium: defining a molecular basis of cardioprotection? Acta Anaesthesiol Scand 2006; 50:414-27. [PMID: 16548853 DOI: 10.1111/j.1399-6576.2006.00984.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Volatile anesthetics can alter cardiac gene and protein expression. Of those underlying molecular changes in gene and protein expression in the myocardium after exposure to volatile anesthetics that have been identified, some of them have been related to cardioprotection. METHODS We used two-dimensional gel electrophoresis and mass spectrometry to identify changes in the protein expression of the left ventricle myocardium of anesthesized rats. We maintained anesthesia for 3 h using isoflurane, sevoflurane or desflurane, respectively, at 1.0 minimum alveolar concentration (MAC) and dissected the left ventricular myocardium either immediately or 72 h after the end of anesthesia. RESULTS We found changes of at least twofold in 106 proteins of the more than 1.600 protein spots discriminated in each gel. These differentially expressed proteins are associated with functions in glycolysis, mitochondrial respiration and stress response. No obvious difference could be observed between the patterns of differential expression of the three volatile anesthetics. CONCLUSION We provide the first study of post-anesthetic protein expression profiles associated with three common volatile anesthetics. These volatile anesthetics promote a distinct change in the myocardial protein expression profile, whereby changes in the expression pattern still exist 72 h after anesthesia. These proteome changes are closely related to cardioprotection and ischemic preconditioning, indicating a common functional signaling of volatile anesthestics.
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Affiliation(s)
- A Kalenka
- Department of Anesthesiology and Critical Care Medicine, Faculty of Clinical Medicine Mannheim, University of Heidelberg, Mannheim, Germany.
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Siroen MPC, Teerlink T, Bolte AC, van Elburg RM, Richir MC, Nijveldt RJ, van der Hoven B, van Leeuwen PAM. No Compensatory Upregulation of Placental Dimethylarginine Dimethylaminohydrolase Activity in Preeclampsia. Gynecol Obstet Invest 2006; 62:7-13. [PMID: 16508323 DOI: 10.1159/000091752] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 01/09/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Placental dysfunction of the asymmetric dimethylarginine (ADMA) degrading enzyme dimethylarginine dimethylaminohydrolase (DDAH) has been suggested as one of the initiating events in the development of preeclampsia (PE). Our primary aim was to investigate the role of the placenta in the metabolism of ADMA during normal pregnancy and PE. METHODS We studied 27 nonpregnant healthy women (C), 15 normotensive pregnant females (P), 16 patients with PE, and 7 patients with the 'hemolysis, elevated liver enzymes and low platelets' syndrome (H). RESULTS There were no significant differences between P and PE with respect to fetomaternal gradient of ADMA, placental DDAH activity and placental ADMA content. During the first stage of labour, mean (+/-SD) plasma ADMA (micromol/l) was higher in H (0.69 +/- 0.22; p < 0.05) compared with C (0.44 +/- 0.07), P (0.37 +/- 0.06), and PE (0.40 +/- 0.06). ADMA was significantly associated with laboratory parameters of hepatic and renal function and with clinical parameters, including systolic and diastolic blood pressure, gestational age, birth weight, and placenta weight. CONCLUSIONS A compensatory upregulation of placental DDAH activity is absent in patients suffering from PE and levels of ADMA in plasma and placenta are normal in patients suffering from PE. However, when the course of PE deteriorates and organ dysfunction (especially liver and kidney) becomes involved, such as during the hemolysis, elevated liver enzymes and low platelets syndrome, ADMA levels increase.
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Affiliation(s)
- Michiel P C Siroen
- Department of Surgery, VU University Medical Center, Amsterdam, The Netherlands
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15
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Schulz R, Rassaf T, Massion PB, Kelm M, Balligand JL. Recent advances in the understanding of the role of nitric oxide in cardiovascular homeostasis. Pharmacol Ther 2005; 108:225-56. [PMID: 15949847 DOI: 10.1016/j.pharmthera.2005.04.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 04/15/2005] [Indexed: 02/04/2023]
Abstract
Nitric oxide synthases (NOS) are the enzymes responsible for nitric oxide (NO) generation. To date, 3 distinct NOS isoforms have been identified: neuronal NOS (NOS1), inducible NOS (NOS2), and endothelial NOS (NOS3). Biochemically, NOS consists of a flavin-containing reductase domain, a heme-containing oxygenase domain, and regulatory sites. NOS catalyse an overall 5-electron oxidation of one Nomega-atom of the guanidino group of L-arginine to form NO and L-citrulline. NO exerts a plethora of biological effects in the cardiovascular system. The basal formation of NO in mitochondria by a mitochondrial NOS seems to be one of the main regulators of cellular respiration, mitochondrial transmembrane potential, and transmembrane proton gradient. This review focuses on recent advances in the understanding of the role of enzyme and enzyme-independent NO formation, regulation of NO bioactivity, new aspects of NO on cardiac function and morphology, and the clinical impact and perspectives of these recent advances in our knowledge on NO-related pathways.
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Affiliation(s)
- R Schulz
- Institut für Pathophysiologie, Zentrum für Innere Medizin des Universitätsklinikums Essen, Germany.
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16
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Chen Y, Li Y, Zhang P, Traverse JH, Hou M, Xu X, Kimoto M, Bache RJ. Dimethylarginine dimethylaminohydrolase and endothelial dysfunction in failing hearts. Am J Physiol Heart Circ Physiol 2005; 289:H2212-9. [PMID: 16024577 DOI: 10.1152/ajpheart.00224.2005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Congestive heart failure (CHF) is associated with impaired endothelium-dependent nitric oxide (NO)-mediated vasodilation (endothelial dysfunction). We hypothesized that coronary endothelial dysfunction in CHF may be due in part to decreased dimethylarginine dimethylaminohydrolase (DDAH), the enzyme that degrades endogenous inhibitors of NO synthase (NOS), including asymmetric dimethylarginine. Coronary blood flow and the endothelium-dependent vasodilator response to acetylcholine were studied in dogs in which CHF was produced by rapid ventricular pacing for 4 wk. Coronary flow and myocardial O2consumption at rest and during treadmill exercise were decreased after development of CHF, and the vasodilator response to intracoronary acetylcholine (75 μg/min) was decreased by 39 ± 5%. DDAH activity and DDAH isoform 2 (DDAH-2) protein content were decreased by 53 ± 13% and 58 ± 14%, respectively, in hearts with CHF, whereas endothelial NOS and DDAH isoform 1 (DDAH-1) were increased. Caveolin-1 and protein arginine N-methyltransferase 1, the enzyme that produces asymmetric dimethylarginine, were unchanged. Immunohistochemical staining showed DDAH-1 strongly expressed in coronary endothelium and smooth muscle and in the sarcolemma of cardiac myocytes. In cultured human endothelial cells, DDAH-1 was uniformly distributed in the cytosol and nucleus, whereas DDAH-2 was found only in the cytosol. Decreased DDAH activity and DDAH-2 protein expression may cause accumulation of endogenous inhibitors of endothelial NOS, thereby contributing to endothelial dysfunction in the failing heart.
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Affiliation(s)
- YingJie Chen
- Department of Medicine, Univ. of Minnesota Medical School, Minneapolis, MN 55455, USA.
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17
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Pedersen LG, Tarnow I, Olsen LH, Teerlink T, Pedersen HD. Body size, but neither age nor asymptomatic mitral regurgitation, influences plasma concentrations of dimethylarginines in dogs. Res Vet Sci 2005; 80:336-42. [PMID: 16182327 DOI: 10.1016/j.rvsc.2005.07.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Revised: 06/27/2005] [Accepted: 07/15/2005] [Indexed: 12/23/2022]
Abstract
Asymmetric dimethylarginine (ADMA) is a marker of various cardiovascular diseases in man. The aim of the present study was to test if Cavalier King Charles Spaniels (CKCS) with varying degrees of mitral regurgitation (MR) had increased plasma concentration of ADMA and furthermore, characterize the plasma level of ADMA and symmetric dimethylarginine (SDMA) in normal dogs. Seventy-six dogs were included (44 CKCS and 32 dogs of other breeds). The CKCS had various degrees of MR, whereas the remaining dogs had either no or minimal MR. Apart from cardiac murmurs, no dogs showed signs of cardiac or systematic disease. The degree of MR had no significant influence on ADMA (P = 0.33). Body weight was directly associated with ADMA (P = 0.0004) and creatinine was directly associated with SDMA (P<0.0001). Furthermore, the plasma concentration of ADMA was three to four times higher than found in healthy humans.
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Affiliation(s)
- L G Pedersen
- Department of Basic Animal and Veterinary Sciences, The Royal Veterinary and Agricultural University, 7 Groennegaardsvej, DK-1870 Frederiksberg C, Copenhagen, Denmark.
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18
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Flögel U, Laussmann T, Gödecke A, Abanador N, Schäfers M, Fingas CD, Metzger S, Levkau B, Jacoby C, Schrader J. Lack of Myoglobin Causes a Switch in Cardiac Substrate Selection. Circ Res 2005; 96:e68-75. [PMID: 15817884 DOI: 10.1161/01.res.0000165481.36288.d2] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Myoglobin is an important intracellular O2 binding hemoprotein in heart and skeletal muscle. Surprisingly, disruption of myoglobin in mice (myo-/-) resulted in no obvious phenotype and normal cardiac function was suggested to be mediated by structural alterations that tend to steepen the oxygen pressure gradient from capillary to mitochondria. Here we report that lack of myoglobin causes a biochemical shift in cardiac substrate utilization from fatty acid to glucose oxidation. Proteome and gene expression analysis uncovered key enzymes of mitochondrial beta-oxidation as well as the nuclear receptor PPAR to be downregulated in myoglobin-deficient hearts. Using FDG-PET we showed a substantially increased in vivo cardiac uptake of glucose in myo-/- mice (6.7+/-2.3 versus 0.8+/-0.5% of injected dose in wild-type, n=5, P<0.001), which was associated with an upregulation of the glucose transporter GLUT4. The metabolic switch was confirmed by 13C NMR spetroscopic isotopomer studies of isolated hearts which revealed that [1,6-13C2]glucose utilization was increased in myo-/- hearts (38+/-8% versus 22+/-5% in wild-type, n=6, P<0.05), and concomitantly, [U-13C16]palmitate utilization was decreased in the myoglobin-deficient group (42+/-6% versus 63+/-11% in wild-type, n=6, P<0.05). Because of the O2-sparing effect of glucose utilization, the observed shift in substrate metabolism benefits energy homoeostasis and therefore represents a molecular adaptation process allowing to compensate for lack of the cytosolic oxygen carrier myoglobin. Furthermore, our data suggest that an altered myoglobin level itself may be a critical determinant for substrate selection in the heart. The full text of this article is available online at http://circres.ahajournals.org.
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Affiliation(s)
- Ulrich Flögel
- Institut für Herz-und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Germany.
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19
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Siroen MPC, van Leeuwen PAM, Nijveldt RJ, Teerlink T, Wouters PJ, Van den Berghe G. Modulation of asymmetric dimethylarginine in critically ill patients receiving intensive insulin treatment: A possible explanation of reduced morbidity and mortality?*. Crit Care Med 2005; 33:504-10. [PMID: 15753739 DOI: 10.1097/01.ccm.0000155784.59297.50] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Asymmetric dimethylarginine, which inhibits production of nitric oxide, has been shown to be a strong and independent predictor of mortality in critically ill patients with clinical evidence of organ dysfunction. Interestingly, intensive insulin therapy in critically ill patients improved morbidity and mortality, but the exact mechanisms by which these beneficial effects are brought about remain unknown. Therefore, we aimed to investigate whether modulation of asymmetric dimethylarginine concentrations by intensive insulin therapy is involved in these effects. DESIGN A prospective, randomized, controlled trial. SETTING A 56-bed predominantly surgical intensive care unit in a tertiary teaching hospital. PATIENTS From a study of 1,548 critically ill patients who were randomized to receive either conventional or intensive insulin therapy, we included 79 patients who were admitted to the intensive care unit after complicated pulmonary and esophageal surgery and required prolonged (>/=7 days) intensive care. INTERVENTIONS Determination of asymmetric dimethylarginine concentrations. MEASUREMENTS AND MAIN RESULTS Asymmetric dimethylarginine concentrations were determined with high-performance liquid chromatography on the day of admission, on day 2, on day 7, and on the last day at the intensive care unit. Although the asymmetric dimethylarginine levels did not change between day 0 and day 2 in patients receiving intensive insulin treatment, there was a significant increase during this period in the conventionally treated patients (p = .043). Interestingly, the mean daily insulin dose was inversely associated with the asymmetric dimethylarginine concentration on the last day (r = -.23, p = .042), and the asymmetric dimethylarginine concentration on the last day at the intensive care unit was significantly lower in the intensive insulin treatment group (p = .048). Furthermore, asymmetric dimethylarginine was positively associated with duration of intensive care unit stay, duration of ventilatory support, duration of inotropic and vasopressor treatment, number of red cell transfusions, duration of antibiotic treatment, presence of critical illness polyneuropathy, mean Acute Physiology and Chronic Health Evaluation II score, and cumulative Therapeutic Intervention Scoring System-28 score. In addition, asymmetric dimethylarginine levels in patients who died were significantly higher compared with survivors, and changes in the course of asymmetric dimethylarginine plasma concentrations were predictive for adverse intensive care unit outcome. CONCLUSIONS Modulation of asymmetric dimethylarginine concentration by insulin at least partly explains the beneficial effects found in critically ill patients receiving intensive insulin therapy.
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Affiliation(s)
- Michiel P C Siroen
- Department of Surgery, VU University Medical Center, Amsterdam, The Netherlands
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20
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Siroen MPC, van der Sijp JRM, Teerlink T, van Schaik C, Nijveldt RJ, van Leeuwen PAM. The human liver clears both asymmetric and symmetric dimethylarginine. Hepatology 2005; 41:559-65. [PMID: 15726655 DOI: 10.1002/hep.20579] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Asymmetric (ADMA) and symmetric dimethylarginine (SDMA) inhibit production of nitric oxide. The concentration of both dimethylarginines is regulated by urinary excretion, although ADMA, but not SDMA, is also subject to degradation by dimethylarginine dimethylaminohydrolase, which is highly expressed in the liver but also present in the kidney. The exact roles of the human liver and kidney in the metabolism of dimethylarginines are currently unknown. Therefore, we aimed to investigate renal and hepatic handling of ADMA and SDMA in detail in 24 patients undergoing hepatic surgery. To calculate net organ fluxes and fractional extraction (FE) rates, blood was collected from an arterial line, the portal vein, hepatic vein, and renal vein, and blood flow of the hepatic artery, portal vein, and renal vein was determined using Doppler ultrasound techniques. Results showed a significant net uptake (median [IQR]) of ADMA in both the liver (9.6 nmol/min [5.6-13.2]) and the kidney (12.1 nmol/min [1.3-17.1]). SDMA uptake was present not only in the kidney (12.7 nmol/min [3.5-25.4]), but also in the liver (7.7 nmol/min [2.8-16.4]). FE rates of ADMA for the liver and kidney were 5.0% (3.5%-7.4%) and 8.4% (1.3%-13.9%), respectively. For SDMA, hepatic and renal FE rates were 3.4% (2.1%-7.5%) and 12.5% (3.6%-16.2%), respectively. In conclusion, this study gives a detailed description of the hepatic and renal elimination of dimethylarginines and shows that the clearing of SDMA is not only confined to the kidney, but the human liver also takes up substantial amounts of SDMA from the portal and systemic circulation.
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Affiliation(s)
- Michiel P C Siroen
- Department of Surgery, VU University Medical Center, Amsterdam, The Netherlands
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21
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Akbar F, Heinonen S, Pirskanen M, Uimari P, Tuomainen TP, Salonen JT. Haplotypic association of DDAH1 with susceptibility to pre-eclampsia. ACTA ACUST UNITED AC 2005; 11:73-7. [PMID: 15501905 DOI: 10.1093/molehr/gah116] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Association between pre-eclampsia (PEE1) and the dimethylarginine dimethylaminohydrolase (DDAH) 1 and 2 genes, which play a role in the regulation of nitric oxide synthesis and release, was studied. In a case-control study design single nucleotide polymorphisms (SNPs) were determined at eight sites in the DDAH1 gene and at one site (Pro231Pro) in the DDAH2 gene from 132 women with pre-eclampsia and 112 healthy controls. Three SNPs in the DDAH1 gene were associated with pre-eclampsia, showing complete linkage disequilibrium with each other, but none of the associations in the allele or genotype data reached statistical significance in either of the genes after the correction for multiple testing. Haplotype frequencies were estimated using a population based on a maximum likelihood method (EM algorithm). Four common DDAH1 haplotypes were present and a significant association of haplotypes H2 and H3 with pre-eclampsia (P=0.03) was found. The risk of pre-eclampsia was greatest in individuals (odds ratio: 3.93; 95% confidence interval: 1.54-9.99) who had two copies of the high-risk haplotypes (H2 or H3). The observed haplotypic association provides the first evidence of the importance of DDAH1 polymorphisms in pre-eclampsia susceptibility.
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Affiliation(s)
- Fareeza Akbar
- Department of Obstetrics and Gynaecology, Kuopio University Hospital, University of Kuopio, Kuopio, Finland
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22
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Schulz R, Gres P, Konietzka I, Heusch G. Regional differences of myocardial infarct development and ischemic preconditioning. Basic Res Cardiol 2004; 100:48-56. [PMID: 15526114 DOI: 10.1007/s00395-004-0497-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2004] [Revised: 10/04/2004] [Accepted: 10/18/2004] [Indexed: 01/19/2023]
Abstract
UNLABELLED The spatial and temporal development of myocardial infarction depends on the area at risk (AAR), the severity and duration of blood flow reduction (energy supply) as well as on heart rate and regional wall function (energy demand). Both supply and demand can vary within the AAR of a given heart, potentially resulting in differences in infarct development. We therefore retrospectively analyzed infarct size (IS, %AAR, TTC) in 24 anesthetized pigs in vivo following 90 min hypoperfusion and 120 min reperfusion of the LAD coronary artery, which supplies parts of the LV septum (LVS) and anterior free wall (LVAFW). The total LAD perfusion territory averaged 49.8 +/- 14.2 (SD) g (49.2 +/- 8.4% of LV); 61.4 +/- 8.1% of the AAR was LVAFW. IS within the LVS was 25.3 +/- 15.1%, while IS within the LVAFW was 16.6 +/-10.1% (p<0.05). While ischemic blood flow (radiolabeled microspheres) did not differ between LVS (0.05 +/- 0.02 ml/min/g) and LVAFW (0.05 +/- 0.03 ml/min/g), perivascular connective tissue (56 +/- 9 vs. 38+/-7 microm(2), p < 0.05) and the capillary-to-myocyte distance (1.65 +/- 0.23 vs. 1.18 +/- 0.23 mm, p < 0.05) were larger in LVS than in LVAFW. Interestingly, IS in LVS (9.3 +/- 9.6%, n = 24) and LVAFW (9.2 +/- 9.1%) were reduced to the same absolute extent by ischemic preconditioning with one cycle of 10 min ischemia and 15 min reperfusion, suggesting that a similar regional difference exists also in the protection afforded by ischemic preconditioning. The mechanism(s) for that remain(s) to be established. CONCLUSION In pigs, regional differences in infarct development and protection from it exist in the LAD perfusion territory, which are independent of ischemic blood flow but apparently related to pre-existing structural differences.
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Affiliation(s)
- Rainer Schulz
- Institute of Pathophysiology, Center of Internal Medicine University of Essen, Medical School, Essen, Germany.
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23
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Nijveldt RJ, Siroen MPC, Teerlink T, van Leeuwen PAM. Elimination of asymmetric dimethylarginine by the kidney and the liver: a link to the development of multiple organ failure? J Nutr 2004; 134:2848S-2852S; discussion 2853S. [PMID: 15465798 DOI: 10.1093/jn/134.10.2848s] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Asymmetric dimethylarginine (ADMA) is a recently recognized endogenous inhibitor of nitric oxide production. Its role in cardiovascular disease is emerging, and ADMA appears to be an important causal factor in dysfunction of the vascular system. Several studies show that ADMA accumulates during renal failure, and ADMA has been identified as causing the cardiovascular complications accompanying renal failure. In addition to the kidney, we recently suggested an important role for the liver as an ADMA-eliminating organ. In a population of critically ill patients, hepatic failure was the most prominent determinant of ADMA concentration, and, notably, high ADMA concentration proved to be a strong and independent risk factor for intensive care unit mortality in these patients. We here summarize the role of both the kidney and the liver in the regulation of ADMA levels. In addition, the potential central role of ADMA as a causative factor in the development of multiple organ failure is discussed.
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Affiliation(s)
- Robert J Nijveldt
- Department of Surgery, VU Univerity Medical Center, Amstredam, The Netherlands
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24
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Decking UKM, Pai VM, Bennett E, Taylor JL, Fingas CD, Zanger K, Wen H, Balaban RS. High-resolution imaging reveals a limit in spatial resolution of blood flow measurements by microspheres. Am J Physiol Heart Circ Physiol 2004; 287:H1132-40. [PMID: 15117718 DOI: 10.1152/ajpheart.00119.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Density of 15-μm microspheres after left atrial application is the standard measure of regional perfusion. In the heart, substantial differences in microsphere density are seen at spatial resolutions <5 ml, implying perfusion heterogeneity. Microsphere deposition imaging permits a superior evaluation of the distribution pattern. Therefore, fluorescent microspheres (FMS) were applied, FMS deposition in the canine heart was imaged by epifluorescence microscopy in vitro, and the patterns were observed compared with MR images of iron oxide microspheres (IMS) obtained in vivo and in vitro. FMS deposition in myocardial slices revealed the following: 1) a nonrandom distribution, with sequentially applied FMS of different color stacked within the same vessel, 2) general FMS clustering, and 3) rather large areas devoid of FMS ( n = 3). This pattern was also seen in reconstructed three-dimensional images (<1 nl resolution) of FMS distribution ( n = 4). Surprisingly, the deposition pattern of sequentially applied FMS remained virtually identical over 3 days. Augmenting flow by intracoronary adenosine (>2 μM) enhanced local microsphere density, but did not alter the deposition pattern ( n = 3). The nonrandom, temporally stable pattern was quantitatively confirmed by a three-dimensional intermicrosphere distance analysis of sequentially applied FMS. T2-weighted short-axis MR images (2-μl resolution) of IMS revealed similar patterns in vivo and in vitro ( n = 6), as seen with FMS. The observed temporally stable microsphere patterns are not consistent with the notion that microsphere deposition is solely governed by blood flow. We propose that at high spatial resolution (<2 μl) structural aspects of the vascular network dominate microsphere distribution, resulting in the organized patterns observed.
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Affiliation(s)
- Ulrich K M Decking
- Department of Cardiovascular Physiology, Heinrich-Heine-University, 40225 Düsseldorf, Germany.
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25
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Kirton RS, Taberner AJ, Nielsen PMF, Young AA, Loiselle DS. Strain softening behaviour in nonviable rat right-ventricular trabeculae, in the presence and the absence of butanedione monoxime. Exp Physiol 2004; 89:593-604. [PMID: 15258118 DOI: 10.1113/expphysiol.2004.027623] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Strain softening is commonly reported during mechanical testing of passive whole hearts. It is typically manifested as a stiffer force-extension relationship in the first deformation cycle relative to subsequent cycles and is distinguished from viscoelasticity by a lack of recovery of stiffness, even after several hours of rest. The cause of this behaviour is presently unknown. In order to investigate its origins, we have subjected trabeculae to physiologically realistic extensions (5-15% of muscle length at 26 degrees C and 0.5 mm Ca(2+)), while measuring passive force and dynamic stiffness. While we did not observe strain softening in viable trabeculae, we found that it was readily apparent in nonviable (electrically inexcitable) trabeculae undergoing the same extensions. This result was obtained in both the presence and absence of 2,3-butanedione monoxime (BDM). Furthermore, BDM had no effect on the passive compliance of viable specimens, while its presence partly inhibited, but could not prevent, stiffening of nonviable specimens. Loss of viability was accompanied by a uniform increase of dynamic stiffness over all frequencies examined (0.2-100 Hz). The presence of strain softening during length extensions of nonviable tissue resulted in a comparable uniform decrease of dynamic stiffness. It is therefore concluded that strain softening is neither intrinsic to viable rat right ventricular trabeculae nor influenced by BDM but, rather, reflects irreversible damage of tissue in partial, or full, rigor.
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Affiliation(s)
- R S Kirton
- Bioengineering Institute, The University of Auckland, 70 Symonds Street, Auckland, New Zealand.
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26
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Schlieper G, Kim JH, Molojavyi A, Jacoby C, Laussmann T, Flögel U, Gödecke A, Schrader J. Adaptation of the myoglobin knockout mouse to hypoxic stress. Am J Physiol Regul Integr Comp Physiol 2004; 286:R786-92. [PMID: 14656764 DOI: 10.1152/ajpregu.00043.2003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myoglobin knockout (myo-/-) mice were previously reported to show no obvious phenotype but revealed several compensatory mechanisms that include increases in cardiac capillary density, coronary flow, and hemoglobin. The aim of this study was to investigate whether severe hypoxic stress can exhaust these compensatory mechanisms and whether this can be monitored on the gene and protein level. Myo-/- and wild-type (WT) mice were exposed to hypoxia (10% O2) for 2 wk. Thereafter hemodynamic parameters were investigated by invasive measurement combined with magnetic resonance imaging. Cardiac gene and protein expression were analyzed using cDNA arrays and two-dimensional gel electrophoresis plus mass spectrometry, respectively. Hematocrit levels increased from 44% (WT) and 48% (myo-/-) to 72% in both groups. Similar to WT controls, hypoxic myo-/- animals maintained stable cardiovascular function (mean arterial blood pressure 82.4 mmHg, ejection fraction 72.5%). Cardiac gene expression of hypoxic myo-/- mice differed significantly from WT controls in 17 genes (e.g., keratinocyte lipid binding protein +202%, cytochrome c oxidase Vb +41%). Interestingly, hypoxia inducible factor-1α remained unchanged in both groups. Proteome analysis revealed reduced levels of heart fatty acid-binding protein and heat shock protein 27 both in hypoxic myo-/- and WT mice. Our data thus demonstrate that myo-/- mice do not decompensate during hypoxic stress but are surprisingly well adapted. Changes in energy metabolism of fatty acids may contribute to the robustness of myoglobin-deficient mice.
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MESH Headings
- Adaptation, Physiological/genetics
- Adaptation, Physiological/physiology
- Animals
- Blood Cell Count
- DNA, Complementary/biosynthesis
- DNA, Complementary/genetics
- Electrophoresis, Polyacrylamide Gel
- Gene Expression Regulation/physiology
- Hemodynamics/physiology
- Hypoxia/physiopathology
- In Situ Hybridization
- Magnetic Resonance Imaging
- Mass Spectrometry
- Mice
- Mice, Knockout
- Myocardium/metabolism
- Myoglobin/genetics
- Myoglobin/physiology
- Oligonucleotide Array Sequence Analysis
- Phenotype
- Protein Biosynthesis
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Stress, Physiological/physiopathology
- Ventricular Function, Left/genetics
- Ventricular Function, Left/physiology
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Affiliation(s)
- Georg Schlieper
- Department of Cardiovascular Physiology, Heinrich-Heine-University, 40225 Düsseldorf, Germany
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27
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Matsumoto T, Tachibana H, Asano T, Takemoto M, Ogasawara Y, Umetani K, Kajiya F. Pattern differences between distributions of microregional myocardial flows in crystalloid- and blood-perfused rat hearts. Am J Physiol Heart Circ Physiol 2004; 286:H1331-8. [PMID: 14670811 DOI: 10.1152/ajpheart.00120.2003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regional myocardial flow distributions in Langendorff rat hearts under Tyrode and blood perfusion were assessed by tracer digital radiography (100-μm resolution). Flow distributions during baseline and maximal hyperemia following a 60-s flow cessation were evaluated by the coefficient of variation of regional flows (CV; related to global flow heterogeneity) and the correlation between adjacent regional flows (CA; inversely related to local flow randomness). These values were obtained for the original images (642 pixels) and for coarse-grained images (322, 162, and 82 blocks of nearby pixels). At a given point in time during baseline, both CV and CA were higher in blood ( n = 7) than in Tyrode perfusion ( n = 7) over all pixel aggregates ( P < 0.05, two-way ANOVA). During the maximal hyperemia, CV and CA were still significantly higher in blood ( n = 7) than in Tyrode perfusion ( n = 7); however, these values decreased substantially in blood perfusion and the CV and CA differences became smaller than those at baseline accordingly. During basal blood perfusion, the 60-s average flow distribution ( n = 7) showed a smaller CV and CA than those at a given point in time ( P < 0.05, two-way ANOVA). Coronary flow reserve was significantly higher in blood than in Tyrode perfusion. In conclusion, the flow heterogeneity and the local flow similarity are both higher in blood than in Tyrode perfusion, probably due to the different degree of coronary tone preservation and the presence or absence of blood corpuscles. Under blood perfusion, temporal flow fluctuations over 60-s order are largely involved in shaping microregional flow distributions.
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Affiliation(s)
- Takeshi Matsumoto
- Department of Medical Engineering and Systems Cardiology, Kawasaki Medical School, Kurashiki, Okayama 701-0192 Japan.
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Zuurbier C. Postischemic Myocardial Metabolism. Semin Cardiothorac Vasc Anesth 2003. [DOI: 10.1177/108925320300700112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- C.J. Zuurbier
- Department of Anesthesiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, The Netherlands
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