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Waddingham MT, Sequeira V, Kuster DWD, Dal Canto E, Handoko ML, de Man FS, da Silva Gonçalves Bós D, Ottenheijm CA, Shen S, van der Pijl RJ, van der Velden J, Paulus WJ, Eringa EC. Geranylgeranylacetone reduces cardiomyocyte stiffness and attenuates diastolic dysfunction in a rat model of cardiometabolic syndrome. Physiol Rep 2023; 11:e15788. [PMID: 37985159 PMCID: PMC10659935 DOI: 10.14814/phy2.15788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 07/20/2023] [Accepted: 07/22/2023] [Indexed: 11/22/2023] Open
Abstract
Titin-dependent stiffening of cardiomyocytes is a significant contributor to left ventricular (LV) diastolic dysfunction in heart failure with preserved LV ejection fraction (HFpEF). Small heat shock proteins (HSPs), such as HSPB5 and HSPB1, protect titin and administration of HSPB5 in vitro lowers cardiomyocyte stiffness in pressure-overload hypertrophy. In humans, oral treatment with geranylgeranylacetone (GGA) increases myocardial HSP expression, but the functional implications are unknown. Our objective was to investigate whether oral GGA treatment lowers cardiomyocyte stiffness and attenuates LV diastolic dysfunction in a rat model of the cardiometabolic syndrome. Twenty-one-week-old male lean (n = 10) and obese (n = 20) ZSF1 rats were studied, and obese rats were randomized to receive GGA (200 mg/kg/day) or vehicle by oral gavage for 4 weeks. Echocardiography and cardiac catheterization were performed before sacrifice at 25 weeks of age. Titin-based stiffness (Fpassive ) was determined by force measurements in relaxing solution with 100 nM [Ca2+ ] in permeabilized cardiomyocytes at sarcomere lengths (SL) ranging from 1.8 to 2.4 μm. In obese ZSF1 rats, GGA reduced isovolumic relaxation time of the LV without affecting blood pressure, EF or LV weight. In cardiomyocytes, GGA increased myofilament-bound HSPB5 and HSPB1 expression. Vehicle-treated obese rats exhibited higher cardiomyocyte stiffness at all SLs compared to lean rats, while GGA reduced stiffness at SL 2.0 μm. In obese ZSF1 rats, oral GGA treatment improves cardiomyocyte stiffness by increasing myofilament-bound HSPB1 and HSPB5. GGA could represent a potential novel therapy for the early stage of diastolic dysfunction in the cardiometabolic syndrome.
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Affiliation(s)
- Mark T. Waddingham
- Department of Physiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
- Department of Cardiac PhysiologyNational Cerebral and Cardiovascular CenterSuitaJapan
| | - Vasco Sequeira
- Department of Physiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
| | - Diederik W. D. Kuster
- Department of Physiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
| | - Elisa Dal Canto
- Department of Physiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
- Laboratory of Experimental CardiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
- Julius Center for Health Sciences and Primary CareUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - M. Louis Handoko
- Department of Cardiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
| | - Frances S. de Man
- Department of Pulmonology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
| | | | - Coen A. Ottenheijm
- Department of Physiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
- Cellular and Molecular MedicineUniversity of ArizonaTucsonArizonaUSA
| | - Shengyi Shen
- Cellular and Molecular MedicineUniversity of ArizonaTucsonArizonaUSA
| | | | - Jolanda van der Velden
- Department of Physiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
| | - Walter J. Paulus
- Department of Physiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
| | - Etto C. Eringa
- Department of Physiology, Amsterdam Cardiovascular SciencesAmsterdam University Medical CentersAmsterdamThe Netherlands
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2
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Waddingham MT, Tsuchimochi H, Sonobe T, Asano R, Jin H, Ow CPC, Schwenke DO, Katare R, Aoyama K, Umetani K, Hoshino M, Uesugi K, Shirai M, Ogo T, Pearson JT. Using Synchrotron Radiation Imaging Techniques to Elucidate the Actions of Hexarelin in the Heart of Small Animal Models. Front Physiol 2022; 12:766818. [PMID: 35126171 PMCID: PMC8814524 DOI: 10.3389/fphys.2021.766818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/23/2021] [Indexed: 11/13/2022] Open
Abstract
The majority of the conventional techniques that are utilized for investigating the pathogenesis of cardiovascular disease in preclinical animal models do not permit microlevel assessment of in situ cardiomyocyte and microvascular functions. Therefore, it has been difficult to establish whether cardiac dysfunction in complex multiorgan disease states, such as heart failure with preserved ejection fraction and pulmonary hypertension, have their origins in microvascular dysfunction or rather in the cardiomyocyte. Herein, we describe our approach of utilizing synchrotron radiation microangiography to, first, ascertain whether the growth hormone secretagogue (GHS) hexarelin is a vasodilator in the coronary circulation of normal and anesthetized Sprague-Dawley rats, and next investigate if hexarelin is able to prevent the pathogenesis of right ventricle (RV) dysfunction in pulmonary hypertension in the sugen chronic hypoxia model rat. We show that acute hexarelin administration evokes coronary microvascular dilation through GHS-receptor 1a and nitric oxide, and through endothelium-derived hyperpolarization. Previous work indicated that chronic exogenous administration of ghrelin largely prevented the pathogenesis of pulmonary hypertension in chronic hypoxia and in monocrotaline models. Unexpectedly, chronic hexarelin administration prior to sugen chronic hypoxia did not prevent RV hypertrophy or RV cardiomyocyte relaxation impairment. Small-angle X-ray scattering revealed that super relaxed myosin filaments contributed to diastolic dysfunction, and that length-dependent activation might contribute to sustained contractility of the RV. Thus, synchrotron-based imaging approaches can reveal novel insights into cardiac and coronary functions in vivo.
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Affiliation(s)
- Mark T. Waddingham
- Department of Advanced Medical Research for Pulmonary Hypertension, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Hirotsugu Tsuchimochi
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Takashi Sonobe
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Ryotaro Asano
- Department of Advanced Medical Research for Pulmonary Hypertension, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Huiling Jin
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Connie P. C. Ow
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Daryl O. Schwenke
- Department of Physiology, School of Biomedical Sciences, Heart Otago, University of Otago, Dunedin, New Zealand
| | - Rajesh Katare
- Department of Physiology, School of Biomedical Sciences, Heart Otago, University of Otago, Dunedin, New Zealand
| | - Kohki Aoyama
- Japan Synchrotron Radiation Research Institute, Harima, Japan
| | - Keiji Umetani
- Japan Synchrotron Radiation Research Institute, Harima, Japan
| | - Masato Hoshino
- Japan Synchrotron Radiation Research Institute, Harima, Japan
| | - Kentaro Uesugi
- Japan Synchrotron Radiation Research Institute, Harima, Japan
| | - Mikiyasu Shirai
- Department of Advanced Medical Research for Pulmonary Hypertension, National Cerebral and Cardiovascular Center, Suita, Japan
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Takeshi Ogo
- Department of Advanced Medical Research for Pulmonary Hypertension, National Cerebral and Cardiovascular Center, Suita, Japan
| | - James T. Pearson
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
- Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
- *Correspondence: James T. Pearson
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Asano R, Ogo T, Morita Y, Kotoku A, Aoki T, Hirakawa K, Nakayama S, Ueda J, Tsuji A, Waddingham MT, Ohta Y, Fukuda T, Ohta-Ogo K, Ishibashi-Ueda H, Noguchi T, Yasuda S. Prognostic value of right ventricular native T1 mapping in pulmonary arterial hypertension. PLoS One 2021; 16:e0260456. [PMID: 34843578 PMCID: PMC8629295 DOI: 10.1371/journal.pone.0260456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/09/2021] [Indexed: 11/18/2022] Open
Abstract
Background Right ventricular function is an important prognostic marker for pulmonary arterial hypertension. Native T1 mapping using cardiovascular magnetic resonance imaging can characterize the myocardium, but accumulating evidence indicates that T1 values of the septum or ventricular insertion points do not have predictive potential in pulmonary arterial hypertension. We aimed to elucidate whether native T1 values of the right ventricular free wall (RVT1) can predict poor outcomes in patients with pulmonary arterial hypertension. Methods This retrospective study included 30 patients with pulmonary arterial hypertension (median age, 45 years; mean pulmonary artery pressure, 41±13 mmHg) and 16 healthy controls (median age, 43 years) who underwent native T1 mapping. RVT1 was obtained from the inferior right ventricular free wall during end systole. Results Patients with pulmonary arterial hypertension had significantly higher native RVT1 than did controls (1384±74 vs. 1217±57 ms, p<0.001). Compared with T1 values of the septum or ventricular insertion points, RVT1 correlated better with the effective right ventricular elastance index (R = −0.53, p = 0.003), ventricular-arterial uncoupling (R = 0.46, p = 0.013), and serum brain natriuretic peptide levels (R = 0.65, p<0.001). Moreover, the baseline RVT1 was an accurate predictor of the reduced right ventricular ejection fraction at the 12-month follow-up (delta -3%). RVT1 was independently associated with composite events of death or hospitalization from any cause (hazard ratio = 1.02, p = 0.002). Conclusions RVT1 was predictive of right ventricular performance and outcomes in patients with pulmonary arterial hypertension. Thus, native T1 mapping in the right ventricular free wall may be an effective prognostic method for pulmonary arterial hypertension.
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Affiliation(s)
- Ryotaro Asano
- Division of Pulmonary Circulation, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
- Department of Advanced Medical Research for Pulmonary Hypertension, National Cerebral and Cardiovascular Centre, Osaka, Japan
- Department of Advanced Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Takeshi Ogo
- Division of Pulmonary Circulation, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
- Department of Advanced Medical Research for Pulmonary Hypertension, National Cerebral and Cardiovascular Centre, Osaka, Japan
- * E-mail:
| | - Yoshiaki Morita
- Department of Radiology, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Akiyuki Kotoku
- Department of Radiology, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Tatsuo Aoki
- Division of Pulmonary Circulation, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Kyoko Hirakawa
- Division of Pulmonary Circulation, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Sayuri Nakayama
- Division of Pulmonary Circulation, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Jin Ueda
- Division of Pulmonary Circulation, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Akihiro Tsuji
- Division of Pulmonary Circulation, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Mark T. Waddingham
- Department of Advanced Medical Research for Pulmonary Hypertension, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Yasutoshi Ohta
- Department of Radiology, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Tetsuya Fukuda
- Department of Radiology, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Keiko Ohta-Ogo
- Department of Pathology, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | | | - Teruo Noguchi
- Department of Advanced Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
| | - Satoshi Yasuda
- Department of Advanced Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Centre, Osaka, Japan
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Reil JC, Reil GH, Kovács Á, Sequeira V, Waddingham MT, Lodi M, Herwig M, Ghaderi S, Kreusser MM, Papp Z, Voigt N, Dobrev D, Meyhöfer S, Langer HF, Maier LS, Linz D, Mügge A, Hohl M, Steendijk P, Hamdani N. CaMKII activity contributes to homeometric autoregulation of the heart: A novel mechanism for the Anrep effect. J Physiol 2020; 598:3129-3153. [PMID: 32394454 DOI: 10.1113/jp279607] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/04/2020] [Indexed: 01/14/2023] Open
Abstract
KEY POINTS The Anrep effect represents the alteration of left ventricular (LV) contractility to acutely enhanced afterload in a few seconds, thereby preserving stroke volume (SV) at constant preload. As a result of the missing preload stretch in our model, the Anrep effect differs from the slow force response and has a different mechanism. The Anrep effect demonstrated two different phases. First, the sudden increased afterload was momentary equilibrated by the enhanced LV contractility as a result of higher power strokes of strongly-bound myosin cross-bridges. Second, the slightly delayed recovery of SV is perhaps dependent on Ca2+ /calmodulin-dependent protein kinase II activation caused by oxidation and myofilament phosphorylation (cardiac myosin-binding protein-C, myosin light chain 2), maximizing the recruitment of available strongly-bound myosin cross-bridges. Short-lived oxidative stress might present a new facet of subcellular signalling with respect to cardiovascular regulation. Relevance for human physiology was demonstrated by echocardiography disclosing the Anrep effect in humans during handgrip exercise. ABSTRACT The present study investigated whether oxidative stress and Ca2+ /calmodulin-dependent protein kinase II (CaMKII) activity are involved in triggering the Anrep effect. LV pressure-volume (PV) analyses of isolated, preload controlled working hearts were performed at two afterload levels (60 and 100 mmHg) in C57BL/6N wild-type (WT) and CaMKII-double knockout mice (DKOCaMKII ). In snap-frozen WT hearts, force-pCa relationship, H2 O2 generation, CaMKII oxidation and phosphorylation of myofilament and Ca2+ handling proteins were assessed. Acutely raised afterload showed significantly increased wall stress, H2 O2 generation and LV contractility in the PV diagram with an initial decrease and recovery of stroke volume, whereas end-diastolic pressure and volume, as well as heart rate, remained constant. Afterload induced increase in LV contractility was blunted in DKOCaMKII -hearts. Force development of single WT cardiomyocytes was greater with elevated afterload at submaximal Ca2+ concentration and associated with increases in CaMKII oxidation and phosphorylation of cardiac-myosin binding protein-C, myosin light chain and Ca2+ handling proteins. CaMKII activity is involved in the regulation of the Anrep effect and associates with stimulation of oxidative stress, presumably starting a cascade of CaMKII oxidation with downstream phosphorylation of myofilament and Ca2+ handling proteins. These mechanisms improve LV inotropy and preserve stroke volume within few seconds.
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Affiliation(s)
- Jan-Christian Reil
- Klinik für Innere Medizin II, Kardiologie, Angiologie und Internistische Intensivmedizin, Universitäres Herzzentrum Lübeck, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Gert-Hinrich Reil
- Klinik für Kardiologie, Klinikum Oldenburg, Innere Medizin I, Oldenburg, Germany
| | - Árpád Kovács
- Institute of Physiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University of Bochum, Bochum, Germany.,Molecular and Experimental Cardiology, Ruhr Universität Bochum, Bochum, Germany
| | - Vasco Sequeira
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, Germany
| | - Mark T Waddingham
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Maria Lodi
- Institute of Physiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University of Bochum, Bochum, Germany.,Molecular and Experimental Cardiology, Ruhr Universität Bochum, Bochum, Germany
| | - Melissa Herwig
- Institute of Physiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University of Bochum, Bochum, Germany.,Molecular and Experimental Cardiology, Ruhr Universität Bochum, Bochum, Germany
| | - Shahrooz Ghaderi
- Institute of Physiology, Ruhr University Bochum, Bochum, Germany
| | - Michael M Kreusser
- Departments of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Zoltán Papp
- Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Niels Voigt
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Svenja Meyhöfer
- Institute for Endocrinology & Diabetes, University of Lübeck, Lübeck, Germany and German Center for Diabetes Research, Neuherberg, Germany
| | - Harald F Langer
- Klinik für Innere Medizin II, Kardiologie, Angiologie und Internistische Intensivmedizin, Universitäres Herzzentrum Lübeck, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Lars S Maier
- Klinik und Poliklinik für innere Medizin II, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Dominik Linz
- Klinik für Innere Medizin III (Kardiologie, Angiologie, Internistische Intensivmedizin), Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Andreas Mügge
- Department of Cardiology, St. Josef-Hospital, Ruhr University of Bochum, Bochum, Germany.,Molecular and Experimental Cardiology, Ruhr Universität Bochum, Bochum, Germany
| | - Mathias Hohl
- Klinik für Innere Medizin III (Kardiologie, Angiologie, Internistische Intensivmedizin), Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Paul Steendijk
- Departments of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Nazha Hamdani
- Institute of Physiology, Ruhr University Bochum, Bochum, Germany.,Department of Cardiology, St. Josef-Hospital, Ruhr University of Bochum, Bochum, Germany.,Molecular and Experimental Cardiology, Ruhr Universität Bochum, Bochum, Germany.,Department Clinical Pharmacology, Ruhr University of Bochum, Bochum, Germany
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Sukumaran V, Tsuchimochi H, Sonobe T, Waddingham MT, Shirai M, Pearson JT. Liraglutide treatment improves the coronary microcirculation in insulin resistant Zucker obese rats on a high salt diet. Cardiovasc Diabetol 2020; 19:24. [PMID: 32093680 PMCID: PMC7038553 DOI: 10.1186/s12933-020-01000-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/13/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Obesity, hypertension and prediabetes contribute greatly to coronary artery disease, heart failure and vascular events, and are the leading cause of mortality and morbidity in developed societies. Salt sensitivity exacerbates endothelial dysfunction. Herein, we investigated the effect of chronic glucagon like peptide-1 (GLP-1) receptor activation on the coronary microcirculation and cardiac remodeling in Zucker rats on a high-salt diet (6% NaCl). METHODS Eight-week old Zucker lean (+/+) and obese (fa/fa) rats were treated with vehicle or liraglutide (LIRA) (0.1 mg/kg/day, s.c.) for 8 weeks. Systolic blood pressure (SBP) was measured using tail-cuff method in conscious rats. Myocardial function was assessed by echocardiography. Synchrotron contrast microangiography was then used to investigate coronary arterial vessel function (vessels 50-350 µm internal diameter) in vivo in anesthetized rats. Myocardial gene and protein expression levels of vasoactive factors, inflammatory, oxidative stress and remodeling markers were determined by real-time PCR and Western blotting. RESULTS We found that in comparison to the vehicle-treated fa/fa rats, rats treated with LIRA showed significant improvement in acetylcholine-mediated vasodilation in the small arteries and arterioles (< 150 µm diameter). Neither soluble guanylyl cyclase or endothelial NO synthase (eNOS) mRNA levels or total eNOS protein expression in the myocardium were significantly altered by LIRA. However, LIRA downregulated Nox-1 mRNA (p = 0.030) and reduced ET-1 protein (p = 0.044) expression. LIRA significantly attenuated the expressions of proinflammatory and profibrotic associated biomarkers (NF-κB, CD68, IL-1β, TGF-β1, osteopontin) and nitrotyrosine in comparison to fa/fa-Veh rats, but did not attenuate perivascular fibrosis appreciably. CONCLUSIONS In a rat model of metabolic syndrome, chronic LIRA treatment improved the capacity for NO-mediated dilation throughout the coronary macro and microcirculations and partially normalized myocardial remodeling independent of changes in body mass or blood glucose.
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Affiliation(s)
- Vijayakumar Sukumaran
- Department of Basic Medical Sciences, College of Medicine, Member of QU Health, Qatar University, Doha, Qatar. .,Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, 564-8565, Japan. .,Department of Pharmacology, College of Medicine, Member of QU Health, Qatar University, Doha, Qatar.
| | - Hirotsugu Tsuchimochi
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, 564-8565, Japan
| | - Takashi Sonobe
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, 564-8565, Japan
| | - Mark T Waddingham
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, 564-8565, Japan.,Department of Advanced Medical Research in Pulmonary Hypertension, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, 564-8565, Japan
| | - Mikiyasu Shirai
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, 564-8565, Japan
| | - James T Pearson
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, 564-8565, Japan.,Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
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6
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Waddingham MT, Sonobe T, Tsuchimochi H, Edgley AJ, Sukumaran V, Chen YC, Hansra SS, Schwenke DO, Umetani K, Aoyama K, Yagi N, Kelly DJ, Gaderi S, Herwig M, Kolijn D, Mügge A, Paulus WJ, Ogo T, Shirai M, Hamdani N, Pearson JT. Diastolic dysfunction is initiated by cardiomyocyte impairment ahead of endothelial dysfunction due to increased oxidative stress and inflammation in an experimental prediabetes model. J Mol Cell Cardiol 2019; 137:119-131. [DOI: 10.1016/j.yjmcc.2019.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/10/2019] [Accepted: 10/18/2019] [Indexed: 12/19/2022]
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7
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Pearson JT, Shirai M, Sukumaran V, Du CK, Tsuchimochi H, Sonobe T, Waddingham MT, Katare R, Schwenke DO. Ghrelin and vascular protection. Vasc Biol 2019; 1:H97-H102. [PMID: 32923960 PMCID: PMC7439925 DOI: 10.1530/vb-19-0024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 09/05/2019] [Indexed: 12/11/2022]
Abstract
Ghrelin is a small peptide with important roles in the regulation of appetite, gut motility, glucose homeostasis as well as cardiovascular protection. This review highlights the role that acyl ghrelin plays in maintaining normal endothelial function by maintaining the balance of vasodilator-vasoconstrictor factors, inhibiting inflammatory cytokine production and immune cell recruitment to sites of vascular injury and by promoting angiogenesis.
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Affiliation(s)
- James T Pearson
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan.,Department of Physiology and Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Mikiyasu Shirai
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Vijayakumar Sukumaran
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Cheng-Kun Du
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Hirotsugu Tsuchimochi
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Takashi Sonobe
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Mark T Waddingham
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Rajesh Katare
- Department of Physiology, HeartOtago, School of Biomedical Sciences University of Otago, Dunedin, New Zealand
| | - Daryl O Schwenke
- Department of Physiology, HeartOtago, School of Biomedical Sciences University of Otago, Dunedin, New Zealand
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8
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Affiliation(s)
- Mark T Waddingham
- From the Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, The Netherlands
| | - Walter J Paulus
- From the Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, The Netherlands.
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9
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Surikow SY, Nguyen TH, Stafford I, Chapman M, Chacko S, Singh K, Licari G, Raman B, Kelly DJ, Zhang Y, Waddingham MT, Ngo DT, Bate AP, Chua SJ, Frenneaux MP, Horowitz JD. Nitrosative Stress as a Modulator of Inflammatory Change in a Model of Takotsubo Syndrome. JACC Basic Transl Sci 2018; 3:213-226. [PMID: 30062207 PMCID: PMC6058954 DOI: 10.1016/j.jacbts.2017.10.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 10/08/2017] [Accepted: 10/10/2017] [Indexed: 10/27/2022]
Abstract
Previous studies have shown that patients with Takotsubo syndrome (TS) have supranormal nitric oxide signaling, and post-mortem studies of TS heart samples revealed nitrosative stress. Therefore, we first showed in a female rat model that isoproterenol induces TS-like echocardiographic changes, evidence of nitrosative stress, and consequent activation of the energy-depleting enzyme poly(ADP-ribose) polymerase-1. We subsequently showed that pre-treatment with an inhibitor of poly(ADP-ribose) polymerase-1 ameliorated contractile abnormalities. These findings thus add to previous reports of aberrant β-adrenoceptor signaling (coupled with nitric oxide synthase activation) to elucidate mechanisms of impaired cardiac function in TS and point to potential methods of treatment.
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Key Words
- 3AB, 3-aminobenzamide
- ANOVA, analysis of variance
- ISO, isoproterenol
- LV, left ventricular
- NFκB, nuclear factor kappa B
- NO, nitric oxide
- NOS, nitric oxide synthase
- NT, nitrotyrosine
- O2–, superoxide
- ONOO–, peroxynitrite
- PAR, poly(ADP-ribose)
- PARP, poly(ADP-ribose) polymerase
- TS, Takotsubo syndrome
- TXNIP, thioredoxin-interacting protein
- Takotsubo cardiomyopathy
- myocardial inflammation
- oxidative stress
- poly(ADP-ribose) polymerase-1
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Affiliation(s)
- Sven Y Surikow
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia.,Basil Hetzel Institute, Adelaide, South Australia, Australia
| | - Thanh H Nguyen
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia.,Basil Hetzel Institute, Adelaide, South Australia, Australia
| | - Irene Stafford
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia
| | - Matthew Chapman
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia
| | - Sujith Chacko
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia
| | - Kuljit Singh
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia.,Basil Hetzel Institute, Adelaide, South Australia, Australia
| | - Giovanni Licari
- Basil Hetzel Institute, Adelaide, South Australia, Australia
| | - Betty Raman
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia.,Basil Hetzel Institute, Adelaide, South Australia, Australia
| | - Darren J Kelly
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Melbourne, Australia
| | - Yuan Zhang
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Melbourne, Australia
| | - Mark T Waddingham
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Melbourne, Australia
| | - Doan T Ngo
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia
| | - Alexander P Bate
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia
| | - Su Jen Chua
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia
| | | | - John D Horowitz
- The Queen Elizabeth Hospital, Department of Cardiology, University of Adelaide, South Australia, Australia.,Basil Hetzel Institute, Adelaide, South Australia, Australia
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10
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Pearson JT, Yoshimoto M, Chen YC, Sultani R, Edgley AJ, Nakaoka H, Nishida M, Umetani K, Waddingham MT, Jin HL, Zhang Y, Kelly DJ, Schwenke DO, Inagaki T, Tsuchimochi H, Komuro I, Yamashita S, Shirai M. Widespread Coronary Dysfunction in the Absence of HDL Receptor SR-B1 in an Ischemic Cardiomyopathy Mouse Model. Sci Rep 2017; 7:18108. [PMID: 29273789 PMCID: PMC5741771 DOI: 10.1038/s41598-017-18485-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/12/2017] [Indexed: 02/02/2023] Open
Abstract
Reduced clearance of lipoproteins by HDL scavenger receptor class B1 (SR-B1) plays an important role in occlusive coronary artery disease. However, it is not clear how much microvascular dysfunction contributes to ischemic cardiomyopathy. Our aim was to determine the distribution of vascular dysfunction in vivo in the coronary circulation of male mice after brief exposure to Paigen high fat diet, and whether this vasomotor dysfunction involved nitric oxide (NO) and or endothelium derived hyperpolarization factors (EDHF). We utilised mice with hypomorphic ApoE lipoprotein that lacked SR-B1 (SR-B1−/−/ApoER61h/h, n = 8) or were heterozygous for SR-B1 (SR-B1+/−/ApoER61h/h, n = 8) to investigate coronary dilator function with synchrotron microangiography. Partially occlusive stenoses were observed in vivo in SR-B1 deficient mice only. Increases in artery-arteriole calibre to acetylcholine and sodium nitroprusside stimulation were absent in SR-B1 deficient mice. Residual dilation to acetylcholine following L-NAME (50 mg/kg) and sodium meclofenamate (3 mg/kg) blockade was present in both mouse groups, except at occlusions, indicating that EDHF was not impaired. We show that SR-B1 deficiency caused impairment of NO-mediated dilation of conductance and microvessels. Our findings also suggest EDHF and prostanoids are important for global perfusion, but ultimately the loss of NO-mediated vasodilation contributes to atherothrombotic progression in ischemic cardiomyopathy.
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Affiliation(s)
- James T Pearson
- Monash Biomedical Imaging Facility, Melbourne, Victoria, Australia. .,Department of Physiology, Monash University, Melbourne, Victoria, Australia. .,Australian Synchrotron, Melbourne, Victoria, Australia. .,National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
| | - Misa Yoshimoto
- National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.,Department of Health Sciences, Nara Women's University, Nara, Japan
| | - Yi Ching Chen
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Rohullah Sultani
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Amanda J Edgley
- Department of Physiology, Monash University, Melbourne, Victoria, Australia.,St Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Hajime Nakaoka
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Makoto Nishida
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Keiji Umetani
- Japan Synchrotron Radiation Research Institute, Harima, Hyogo, Japan
| | - Mark T Waddingham
- St Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Hui-Ling Jin
- National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Yuan Zhang
- St Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Darren J Kelly
- St Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Daryl O Schwenke
- Department of Physiology - HeartOtago, University of Otago, Dunedin, New Zealand
| | - Tadakatsu Inagaki
- National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | | | - Issei Komuro
- Department of Cardiovascular Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Shizuya Yamashita
- Departments of Community Medicine and Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Rinku General Medical Center, Izumisano, Osaka, Japan
| | - Mikiyasu Shirai
- National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
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11
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Paulus WJ, Waddingham MT. Racial Tension in Hypertension: Divergent Effects of African and European Ancestry on Cardiac Remodeling. JACC Heart Fail 2017; 5:166-168. [PMID: 28089315 DOI: 10.1016/j.jchf.2016.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 11/09/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Walter J Paulus
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands.
| | - Mark T Waddingham
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands
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12
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Waddingham MT, Edgley AJ, Astolfo A, Inagaki T, Fujii Y, Du CK, Zhan DY, Tsuchimochi H, Yagi N, Kelly DJ, Shirai M, Pearson JT. Chronic Rho-kinase inhibition improves left ventricular contractile dysfunction in early type-1 diabetes by increasing myosin cross-bridge extension. Cardiovasc Diabetol 2015; 14:92. [PMID: 26194354 PMCID: PMC4509700 DOI: 10.1186/s12933-015-0256-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/25/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Impaired actin-myosin cross-bridge (CB) dynamics correlate with impaired left ventricular (LV) function in early diabetic cardiomyopathy (DCM). Elevated expression and activity of Rho kinase (ROCK) contributes to the development of DCM. ROCK targets several sarcomeric proteins including myosin light chain 2, myosin binding protein-C (MyBP-C), troponin I (TnI) and troponin T that all have important roles in regulating CB dynamics and contractility of the myocardium. Our aim was to examine if chronic ROCK inhibition prevents impaired CB dynamics and LV dysfunction in a rat model of early diabetes, and whether these changes are associated with changes in myofilament phosphorylation state. METHODS Seven days post-diabetes induction (65 mg/kg ip, streptozotocin), diabetic rats received the ROCK inhibitor, fasudil (10 mg/kg/day ip) or vehicle for 14 days. Rats underwent cardiac catheterization to assess LV function simultaneous with X-ray diffraction using synchrotron radiation to assess in situ CB dynamics. RESULTS Compared to controls, diabetic rats developed mild systolic and diastolic dysfunction, which was attenuated by fasudil. End-diastolic and systolic myosin proximity to actin filaments were significantly reduced in diabetic rats (P < 0.05). In all rats there was an inverse correlation between ROCK1 expression and the extension of myosin CB in diastole, with the lowest ROCK expression in control and fasudil-treated diabetic rats. In diabetic and fasudil-treated diabetic rats changes in relative phosphorylation of TnI and MyBP-C were not significant from controls. CONCLUSIONS Our results demonstrate a clear role for ROCK in the development of LV dysfunction and impaired CB dynamics in early DCM.
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Affiliation(s)
- Mark T Waddingham
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Melbourne, VIC, Australia.
| | - Amanda J Edgley
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Melbourne, VIC, Australia. .,Department of Physiology, Monash University, Clayton, VIC, Australia.
| | - Alberto Astolfo
- Australian Synchrotron, Clayton, VIC, Australia. .,Department of Medical Physics and Bioengineering, University College of London, London, England, UK.
| | - Tadakatsu Inagaki
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
| | - Yutaka Fujii
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
| | - Cheng-Kun Du
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
| | - Dong-Yun Zhan
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
| | - Hirotsugu Tsuchimochi
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
| | - Naoto Yagi
- Japan Synchrotron Radiation Research Institute, Harima, Hyogo, Japan.
| | - Darren J Kelly
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Melbourne, VIC, Australia.
| | - Mikiyasu Shirai
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
| | - James T Pearson
- Department of Physiology, Monash University, Clayton, VIC, Australia. .,Australian Synchrotron, Clayton, VIC, Australia. .,Monash Biomedical Imaging Facility, Monash University, Clayton, VIC, Australia.
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13
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Waddingham MT, Edgley AJ, Tsuchimochi H, Kelly DJ, Shirai M, Pearson JT. Contractile apparatus dysfunction early in the pathophysiology of diabetic cardiomyopathy. World J Diabetes 2015; 6:943-960. [PMID: 26185602 PMCID: PMC4499528 DOI: 10.4239/wjd.v6.i7.943] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 12/30/2014] [Accepted: 03/09/2015] [Indexed: 02/05/2023] Open
Abstract
Diabetes mellitus significantly increases the risk of cardiovascular disease and heart failure in patients. Independent of hypertension and coronary artery disease, diabetes is associated with a specific cardiomyopathy, known as diabetic cardiomyopathy (DCM). Four decades of research in experimental animal models and advances in clinical imaging techniques suggest that DCM is a progressive disease, beginning early after the onset of type 1 and type 2 diabetes, ahead of left ventricular remodeling and overt diastolic dysfunction. Although the molecular pathogenesis of early DCM still remains largely unclear, activation of protein kinase C appears to be central in driving the oxidative stress dependent and independent pathways in the development of contractile dysfunction. Multiple subcellular alterations to the cardiomyocyte are now being highlighted as critical events in the early changes to the rate of force development, relaxation and stability under pathophysiological stresses. These changes include perturbed calcium handling, suppressed activity of aerobic energy producing enzymes, altered transcriptional and posttranslational modification of membrane and sarcomeric cytoskeletal proteins, reduced actin-myosin cross-bridge cycling and dynamics, and changed myofilament calcium sensitivity. In this review, we will present and discuss novel aspects of the molecular pathogenesis of early DCM, with a special focus on the sarcomeric contractile apparatus.
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14
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Pearson JT, Jenkins MJ, Edgley AJ, Sonobe T, Joshi M, Waddingham MT, Fujii Y, Schwenke DO, Tsuchimochi H, Yoshimoto M, Umetani K, Kelly DJ, Shirai M. Acute Rho-kinase inhibition improves coronary dysfunction in vivo, in the early diabetic microcirculation. Cardiovasc Diabetol 2013; 12:111. [PMID: 24059472 PMCID: PMC3734116 DOI: 10.1186/1475-2840-12-111] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 07/30/2013] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVES Activation of RhoA/Rho-kinase (ROCK) is increasingly implicated in acute vasospasm and chronic vasoconstriction in major organ systems. Therefore we aimed to ascertain whether an increase in ROCK activity plays a role in the deterioration of coronary vascular function in early stage diabetes. METHODS Synchrotron radiation microangiography was used to determine in vivo coronary responses in diabetic (3 weeks post streptozotocin 65 mg/kg ip) and vehicle treated male Sprague-Dawley rats (n = 8 and 6). Changes in vessel number and calibre during vasodilator stimulation before and after blockade of nitric oxide synthase and cyclooxygenase were compared between rats. Acute responses to ROCK inhibitor, fasudil (10 mg/kg iv) was evaluated. Further, perivascular and myocardial fibrosis, arterial intimal thickening were assessed by histology, and capillary density, nitrotyrosine and ROCK1/2 expressions were evaluated by immunohistochemical staining. RESULTS Diabetic rats had significantly elevated plasma glucose (P < 0.001 vs control), but did not differ in fibrotic scores, media to lumen ratio, capillary density or baseline visible vessel number or calibre. Responses to acetylcholine and sodium nitroprusside stimulation were similar between groups. However, in comparison to control rats the diabetic rats showed more segmental constrictions during blockade, which were not completely alleviated by acetylcholine, but were alleviated by fasudil. Further, second order vessel branches in diabetic rats were significantly more dilated relative to baseline (37% vs 12% increase, P < 0.05) after fasudil treatment compared to control rats, while visible vessel number increased in both groups. ROCK2 expression was borderline greater in diabetic rat hearts (P < 0.053). CONCLUSIONS We found that ahead of the reported decline in coronary endothelial vasodilator function in diabetic rats there was moderate elevation in ROCK expression, more widespread segmental constriction when nitric oxide and prostacyclin production were inhibited and notably, increased calibre in second and third order small arteries-arterioles following ROCK inhibition. Based on nitrotyrosine staining oxidative stress was not significantly elevated in early diabetic rats. We conclude that tonic ROCK mediated vasoconstriction contributes to coronary vasomotor tone in early diabetes.
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Affiliation(s)
- James T Pearson
- Department of Physiology, Monash University, Melbourne, Australia
- Monash Biomedical Imaging Facility, Melbourne, Australia
- Australian Synchrotron, Melbourne, Australia
| | - Mathew J Jenkins
- Department of Physiology, Monash University, Melbourne, Australia
- Department of Medicine, St Vincent’s Hospital, University of Melbourne, Melbourne, Australia
| | - Amanda J Edgley
- Department of Physiology, Monash University, Melbourne, Australia
- Department of Medicine, St Vincent’s Hospital, University of Melbourne, Melbourne, Australia
| | - Takashi Sonobe
- National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Mandar Joshi
- The Ritchie Centre, Monash Institute of Medical Research, Melbourne, Australia
| | - Mark T Waddingham
- Department of Physiology, Monash University, Melbourne, Australia
- Department of Medicine, St Vincent’s Hospital, University of Melbourne, Melbourne, Australia
| | - Yutaka Fujii
- National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Daryl O Schwenke
- Department of Physiology, Otago University, Dunedin, New Zealand
| | | | - Misa Yoshimoto
- National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Keiji Umetani
- Japan Synchrotron Radiation Research Institute, Harima, Japan
| | - Darren J Kelly
- Department of Medicine, St Vincent’s Hospital, University of Melbourne, Melbourne, Australia
| | - Mikiyasu Shirai
- National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
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