scholarly journals SERCA2a stimulation by istaroxime improves intracellular Ca2+ handling and diastolic dysfunction in a model of diabetic cardiomyopathy

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
E Torre ◽  
M Arici ◽  
AM Lodrini ◽  
M Ferrandi ◽  
P Barassi ◽  
...  
Keyword(s):  
Diastolic Dysfunction ◽  
Diabetic Cardiomyopathy ◽  
Therapeutic Approach ◽  
Cardiac Fibrosis ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Intact Cells ◽  
Funding Sources ◽  
Promising Therapeutic Approach

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by CVie Therapeutics Limited (Taipei, Taiwan) and Windtree Therapeutics (Warrington, USA) Diabetic cardiomyopathy is a multifactorial disease characterized by an early onset of diastolic dysfunction (DD) that precedes the development of systolic impairment. Mechanisms that can restore cardiac relaxation improving intracellular Ca2+ dynamics represent a promising therapeutic approach for cardiovascular diseases associated to DD. Istaroxime has the double property to accelerate Ca2+ uptake into sarcoplasmic reticulum (SR) through the SR Ca2+ pump (SERCA2a) stimulation and to inhibit Na+/K+ ATPase (NKA). The project aims to characterize istaroxime effects at a concentration (100 nM) marginally affecting NKA, in order to highlight its effects dependent on the stimulation of SERCA2a in a model of mild diabetes. Streptozotocin (STZ) treated diabetic rats were studied at 9 weeks after STZ injection in comparison to controls (CTR). Istaroxime effects were evaluated in vivo and in left ventricular (LV) preparations. STZ animals showed 1) marked DD not associated to cardiac fibrosis, 2) LV mass reduction associated to reduced LV cell dimension and T-tubules loss, 3) reduced LV SERCA2 protein level and activity and 4) slower SR Ca2+ uptake rate, 5) LV action potential (AP) prolongation and increased short-term variability (STV) of AP duration, 6) increased diastolic Ca2+, 7) unaltered SR Ca2+ content and stability in intact cells. Acute istaroxime infusion (0.11 mg/kg/min for 15 min) reduced DD in STZ rats. Accordingly, in STZ myocytes istaroxime (100 nM) stimulated SERCA2a activity and blunted STZ-induced abnormalities in LV Ca2+ dynamics. In CTR myocytes, istaroxime increased diastolic Ca2+ level due to NKA blockade albeit minimal, while its effects on SERCA2a were almost absent. SERCA2a stimulation by istaroxime improved STZ-induced DD and intracellular Ca2+ handling anomalies. Thus, SERCA2a stimulation can be considered a promising therapeutic approach for DD treatment. Abstract Figure.

scholarly journals SERCA2a stimulation by istaroxime improves intracellular Ca2+ handling and diastolic dysfunction in a model of diabetic cardiomyopathy

2021 ◽  
Author(s):  
Eleonora Torre ◽  
Martina Arici ◽  
Alessandra Maria Lodrini ◽  
Mara Ferrandi ◽  
Paolo Barassi ◽  
...  
Keyword(s):  
Diastolic Dysfunction ◽  
Diabetic Cardiomyopathy ◽  
Therapeutic Approach ◽  
Cardiac Fibrosis ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Intact Cells ◽  
Promising Therapeutic Approach ◽  
Mild Diabetes

Abstract Aims  Diabetic cardiomyopathy is a multifactorial disease characterized by an early onset of diastolic dysfunction (DD) that precedes the development of systolic impairment. Mechanisms that can restore cardiac relaxation improving intracellular Ca2+ dynamics represent a promising therapeutic approach for cardiovascular diseases associated to DD. Istaroxime has the dual properties to accelerate Ca2+ uptake into sarcoplasmic reticulum (SR) through the SR Ca2+ pump (SERCA2a) stimulation and to inhibit Na+/K+ ATPase (NKA). This project aims to characterize istaroxime effects at a concentration (100 nmol/L) marginally affecting NKA, in order to highlight its effects dependent on the stimulation of SERCA2a in an animal model of mild diabetes. Methods and results  Streptozotocin (STZ) treated diabetic rats were studied at 9  weeks after STZ injection in comparison to controls (CTR). Istaroxime effects were evaluated in vivo and in left ventricular (LV) preparations. STZ animals showed (i) marked DD not associated to cardiac fibrosis, (ii) LV mass reduction associated to reduced LV cell dimension and T-tubules loss, (iii) reduced LV SERCA2 protein level and activity and (iv) slower SR Ca2+ uptake rate, (v) LV action potential (AP) prolongation and increased short-term variability (STV) of AP duration, (vi) increased diastolic Ca2+, and (vii) unaltered SR Ca2+ content and stability in intact cells. Acute istaroxime infusion (0.11 mg/kg/min for 15 min) reduced DD in STZ rats. Accordingly, in STZ myocytes istaroxime (100 nmol/L) stimulated SERCA2a activity and blunted STZ-induced abnormalities in LV Ca2+ dynamics. In CTR myocytes, istaroxime increased diastolic Ca2+ level due to NKA blockade albeit minimal, while its effects on SERCA2a were almost absent. Conclusions  SERCA2a stimulation by istaroxime improved STZ-induced DD and intracellular Ca2+ handling anomalies. Thus, SERCA2a stimulation can be considered a promising therapeutic approach for DD treatment.

scholarly journals Exogenous Hydrogen Sulfide Alleviated Left Ventricular Fibrosis Via Enhancing Cardiac Autophagy and Decreasing Cardiomyocyte Apoptosis in StreptozotocinInduced Diabetic Rats: From Network Pharmacology to Experimental Pharmacology

2020 ◽  
pp. 1-8
Author(s):  
Shumin Liu ◽  
Cheng Fang ◽  
Feixue Dong ◽  
Liangyou Zhao ◽  
Yongwu Liu ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Diabetic Cardiomyopathy ◽  
Cardiac Fibrosis ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Expression Level ◽  
Network Pharmacology ◽  
Control Group ◽  
Associated Proteins

Streptozotocin (STZ)-induced diabetes mellitus (DM) model shows the signal of cardiac dysfunction, which is manifested as myocardial fibrosis and hypertrophy. This study was designed to predict targets of sodium hydrosulfide (NaHS) for diabetic cardiomyopathy and its corresponding triggered pathways by network pharmacology analysis and test the effects of NaHS as well as its mechanism as possible modulators of left ventricular remodeling in diabetic rats. The drug-target networks were constructed via approaches of network pharmacology, and the predicted targets and pathways were validated by in vivo experiments. Rats were randomly divided into 3 groups (n=6/group): STZ-induced DM group (STZDM); STZ-induced DM treated with H2S group (STZ-NaHS); control group. The control group was treated with daily saline (i.p.); the diabetic model was induced by intraperitoneal (i.p.) injections of 40 mg/kg/day STZ. After 12 weeks, the rat cardiac function was determined, and the pathological morphology of the heart was analysed by Masson trichrome staining in each group. The expression level of matrix metalloproteinase 9 (AGEs), CSE, CBS and several autophagy associated proteins were detected by the ELISA analysis. Results from the PPI network implied that 27 targets were key regulators. The AGE-RAGE signaling pathway in diabetic complications and the apoptotic signaling pathway was discovered to be the key to anti-diabetic cardiomyopathy of NaHS upon the GO enrichment analyses and KEGG pathway. In the in vivo experiment, compared with the control group, cardiac fibrosis and attenuated left ventricular function were observed. Furthermore, compared with the control group, the expression level of CSE, CBS and autophagy associated proteins Atg5 was significantly decreased, while that of AGEs, autophagy associated proteins p62 and p-ERK1/2 was significantly increased in the STZDM group (P<0.05). In the STZ-NaHS group, cardiac fibrosis and ventricular dysfunction were ameliorated, the expression level of CSE, CBS and autophagy associated proteins Atg5 was increased, and the expression level of AGEs, autophagy associated proteins p62 and p-ERK1/2 was significantly decreased (P<0.05). In conclusion, H2S may alleviate cardiac fibrosis of the STZ-induced DM rat model by enhancing cardiac autophagy, inhibiting cardiomyocyte apoptosis and downregulating p-ERK1/2.

Mangiferin mitigates diabetic cardiomyopathy in streptozotocin-diabetic rats

2013 ◽  
Vol 91 (9) ◽  
pp. 759-763 ◽  
Author(s):  
Jun Hou ◽  
Dezhi Zheng ◽  
Guocheng Zhong ◽  
Yonghe Hu
Keyword(s):  
Cardiac Function ◽  
Diabetic Cardiomyopathy ◽  
Cardiac Fibrosis ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Matrix Metalloproteinase 2 ◽  
Severe Left Ventricular Dysfunction ◽  
Streptozotocin Diabetic Rats ◽  
Histopathologic Analysis ◽  
Myocardial Collagen

The purpose of this study was to investigate the cardioprotective effect of mangiferin on diabetic cardiomyopathy (DCM). The DCM model was induced by a high-fat diet and a low dose of streptozotocin. We evaluated the characteristics of DCM by serial echocardiography, electron microscopy, histopathologic analysis of cardiomyocyte fibrosis area, and Western blot analysis of matrix metalloproteinase-2 (MMP-2) and MMP-9 expression. Rats with DCM showed severe left ventricular dysfunction and cardiac fibrosis. Mangiferin mitigated DCM and prevented the accumulation of myocardial collagen. These anatomic findings were accompanied by significant improvements in cardiac function. Based on these results, we conclude that mangiferin has a therapeutic effect on DCM and improves cardiac function.

Abstract 3430: Left Ventricular Hypertrophy and Diastolic Dysfunction in Mice Lacking All Nitric Oxide Synthase Isoforms

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Masato Tsutsui ◽  
Kiyoko Shibata ◽  
Hiroaki Shimokawa ◽  
Yasuko Yatera ◽  
Yumi Furuno ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Diastolic Dysfunction ◽  
Cardiac Fibrosis ◽  
Systolic Function ◽  
Left Ventricular ◽  
Functional Changes ◽  
Arterial Blood ◽  
Oxide Synthase

We have recently succeeded in developing mice in which all three nitric oxide synthase isoforms (nNOS, iNOS, and eNOS) are completely disrupted ( PNAS 2005). In this study, we examined cardiac morphology and function in those mice. Cardiac echocardiography and left ventricular (LV) hemodynamic measurement were performed in male wild-type (WT), singly nNOS −/− , iNOS −/− , eNOS −/− , and triply n/i/eNOS −/− mice at 2 and 5 months of age (n=5–8). At 2 months of age, no significant cardiac morphological or functional changes were detected in any strains studied. However, at 5 months of age, significant LV hypertrophy (wall thickness, mm) were noted in the triply n/i/eNOS −/− mice (1.3±0.1, P <0.01) and to a lesser extent in the singly eNOS −/− mice (1.1±0.1, P <0.05), but not in the singly nNOS −/− (0.8±0.1) or iNOS −/− mice (1.0±0.1), as compared with the WT mice (1.0±0.2). Furthermore, significant LV diastolic dysfunction (as evaluated by echocardiographic E/A ratio and by hemodynamic peak negative dP/dt), with preserved LV systolic function (as assessed by echocardiographic ejection fraction and by hemodynamic peak positive dP/dt), was noted only in the 5-month-old triply n/i/eNOS −/− mice (2.7±0.1 and 2505±60, both P <0.05), but not in any singly nNOS −/− (2.1±0.2 and 3833±402), iNOS −/− (2.0±0.1 and 3773±747), or eNOS −/− mice (2.0±0.3 and 2934±122), as compared with the WT mice (1.9±0.1 and 4038±344). In addition, significant cardiac fibrosis (fibrosis area, %, Masson-trichrome staining) was also detected only in the 5-month-old triply n/i/eNOS −/− mice (1.4±0.2, P <0.05) compared with the WT mice (0.3±0.1). Importantly, arterial blood pressure (mmHg, tail-cuff method) was significantly elevated in the triply n/i/eNOS −/− (143±3.1, P <0.05) than in the WT mice (104±7.3), but the hypertensive level was comparable to that in the singly eNOS −/− mice (140±8.5). Thus, mechanism(s) other than hypertension appears to be involved in the cardiac abnormalities of the triply n/i/eNOS −/− mice. These results provide the first evidence that genetic disruption of all NOSs results in LV hypertrophy and diastolic dysfunction in mice in vivo, suggesting a pivotal role of the NOS system in maintaining cardiac homeostasis.

Abstract 16485: The Nitroxyl Donor 1-Nitrosocyclohexyl Acetate Limits Cardiac Superoxide Upregulation and Diastolic Dysfunction in a Mouse Model of Diabetic Cardiomyopathy

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Rebecca H Ritchie ◽  
Nga Cao ◽  
Yung George Wong ◽  
Sarah Rosli ◽  
Helen Kiriazis ◽  
...  
Keyword(s):  
Heart Failure ◽  
Mouse Model ◽  
Diastolic Dysfunction ◽  
Diabetic Cardiomyopathy ◽  
Ex Vivo ◽  
Systolic Function ◽  
Left Ventricular ◽  
Cardiomyocyte Hypertrophy ◽  
Lv Diastolic Dysfunction ◽  
The Impact

Nitroxyl (HNO), a redox congener of NO•, is a novel regulator of cardiovascular function combining vasodilator and positive inotropic properties. Our previous studies have demonstrated these properties occur concomitantly in the intact heart; HNO moreover also exhibits antihypertrophic and superoxide-suppressing actions. HNO donors may thus offer favorable actions in heart failure. The impact of chronic HNO donor administration has however yet to be reported in this context. We tested the hypothesis that the HNO donor 1-nitrosocyclohexyl acetate (1-NCA) limits cardiomyocyte hypertrophy and left ventricular (LV) diastolic dysfunction in a mouse model of diabetic cardiomyopathy in vivo. Male 6 week-old FVB/N mice received either streptozotocin (55 mg/kg/day i.p. for 5 days, n=17), to induce type 1 diabetes, or citrate vehicle (n=16). After 4 weeks of hyperglycemia, mice were allocated to 1-NCA therapy (83mg/kg/day i.p.) or vehicle, and followed for a further 4 weeks. As shown in the table, blood glucose was unaffected by 1-NCA. LV diastolic dysfunction was evident in diabetic mice, measured as echocardiography-derived A wave velocity, deceleration time and E:A ratio; LV systolic function was preserved. Diabetes-induced diastolic dysfunction was accompanied by increased LV cardiomyocyte size, hypertrophic and pro-fibrotic gene expression, and upregulation of LV superoxide. These characteristics of diabetic cardiomyopathy were largely prevented by 1-NCA treatment. Selectivity of 1-NCA as a donor of HNO versus NO• was demonstrated by the sensitivity of the coronary vasodilation response of 1-NCA to the HNO scavenger L-cysteine (4mM), but not to the NO• scavenger hydroxocobalamin (50μM), in the normal rat heart ex vivo (n=3-7). Collectively, our studies provide the first evidence that HNO donors may represent a promising new strategy for the treatment of diabetic cardiomyopathy, and implies their therapeutic efficacy in settings of chronic heart failure.

Left Ventricular Diastolic Dysfunction as an Early Manifestation of Diabetic Cardiomyopathy

Cardiology ◽  
2002 ◽  
Vol 98 (1-2) ◽  
pp. 33-39 ◽  
Author(s):  
C.M. Schannwell ◽  
M. Schneppenheim ◽  
S. Perings ◽  
G. Plehn ◽  
B.E. Strauer
Keyword(s):  
Diastolic Dysfunction ◽  
Diabetic Cardiomyopathy ◽  
Left Ventricular Diastolic Dysfunction ◽  
Left Ventricular ◽  
Ventricular Diastolic Dysfunction ◽  
Early Manifestation

Protective effects of BiP inducer X (BIX) against diabetic cardiomyopathy in rats

2020 ◽  
Author(s):  
Gholamreza Idari ◽  
Pouran Karimi ◽  
Samad Ghaffari ◽  
Seyed Isaac Hashemy ◽  
Baratali Mashkani
Keyword(s):  
Er Stress ◽  
Diabetic Cardiomyopathy ◽  
Cell Apoptosis ◽  
Cardiac Fibrosis ◽  
Tissue Expression ◽  
Myocardial Cell ◽  
Diabetic Rats ◽  
Mrna Levels ◽  
Protective Effects ◽  
Cardiac Cell

Diabetic cardiomyopathy (DC) is associated with impaired endoplasmic reticulum (ER) function, development of ER stress, and induction of cardiac cell apoptosis. Preventive effects of BiP inducer X (BIX) were investigated against DC characteristic changes in a type 2 diabetes rat model. To establish diabetes, a high-fat diet and a single dose of streptozotocin were administered. Then, animals were assigned into following groups: control, BIX, diabetic animals monitored for one, two, and three weeks. Diabetic rats treated with BIX for one, two, and three weeks. Expressions of various ER stress and apoptotic markers were assessed by immunoblotting method. CHOP gene expression was assessed by Real-time PCR. Tissue expression of BiP was evaluated by immunohistochemistry method. Hematoxylin and eosin and Masson's trichrome staining were performed to assess histological changes in the left ventricle. Cardiac cell apoptosis was examined using TUNEL assay. BIX administration suppressed the activation of the ER stress markers and cleavage of pro-caspase 3 in the diabetic rats. Likewise, tissue expression of BiP protein was increased, while CHOP mRNA levels were decreased. These results were accompanied by reducing cardiac fibrosis and myocardial cell apoptosis suggesting protective effects of BIX against the development of DC by decreasing cardiomyocyte apoptosis and fibrosis.

Key factors of diastolic dysfunction and abnormal left ventricular relaxation in diabetic rats

2020 ◽  
Vol 47 (3) ◽  
pp. 347-356
Author(s):  
Pitipat Kitpipatkun ◽  
Katsuhiro Matsuura ◽  
Kazumi Shimada ◽  
Akiko Uemura ◽  
Seijirow Goya ◽  
...  
Keyword(s):  
Diastolic Dysfunction ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Key Factors ◽  
Left Ventricular Relaxation ◽  
Ventricular Relaxation

P6341Impact of left-ventricular hemodynamics on treadmill exercise intolerance in conscious rats: pilot evaluation in animals with diastolic dysfunction

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
B S Ferguson ◽  
N Bennett ◽  
C Zambataro ◽  
R Shimkunas ◽  
C L Del Rio
Keyword(s):  
Heart Rate ◽  
Blood Glucose ◽  
Diastolic Dysfunction ◽  
Exercise Capacity ◽  
Acute Exercise ◽  
Left Ventricular ◽  
Treadmill Running ◽  
Exercise Intolerance ◽  
Volitional Exhaustion

Abstract Introduction Exercise intolerance is a clinical hallmark of patients with hypertrophic cardiomyopathy and/or impaired diastolic function. Elevated LV filling pressures, particularly in response to acute exercise bouts, are thought to play a role limiting exercise capacity in ventricles with abnormal relaxation/compliance. However, it is experimentally difficult to obtain in vivo hemodynamic measures necessary for the evaluation of centrally mediated dysfunction. Leveraging radio-telemetry, we evaluated central hemodynamic parameters as mediators of exercise intolerance in obese ZSF1 rats with diabetes, hypertension, and diastolic dysfunction. Methods Both ZSF1 (637+12g, n=8) and age-matched (28 weeks) healthy control (CTRL, 543+14g, n=4, P<0.05) rats were instrumented for telemetric left-ventricular pressure (LVP) recordings. Following surgical recovery rats were familiarized to treadmill running and subsequently challenged with an exercise protocol aimed at increasing heart rate by 200 beats/min (5° incline, 15 m/min, increased by 3 m/min every 2-min) until volitional exhaustion. LV pressures were collected continuously during cage resting, treadmill resting, and post-exercise until heart rate returned to baseline. Additionally, resting echocardiographic and blood glucose measures were collected. Results At rest, ZSF1 rats had preserved ejection fraction (73+6 vs 79+9%), elevated (P<0.05) blood glucose (237+83 vs 94+23 mg/dL), end-systolic (147+18 vs 103+13 mmHg), and end-diastolic pressures (16+3 vs 9+3 mmHg), with preserved indexed end-diastolic volumes (670+95 vs 741+89 μL/kg), suggesting impaired diastolic compliance. ZSF1 rats terminated exercise prematurely (8:26+1:20 vs 10:27+1:18 min, P<0.05), indicating a limitation in exercise capacity. This early volitional exhaustion was noted while end-diastolic pressures were not further increased (17+7 mmHg), suggesting that other pathological derangement may play a role modulating exercise capacity. For instance, ZSF1 rats tended to have a blunted increase in the systolic index dP/dt40 (+2589+1450 vs +3938+749 mmHg/s, P<0.1) despite achieving comparable increases in HR (193+34 vs 196+38 bpm) with exercise. Conclusion This pilot study demonstrates the feasibility for evaluation of left-ventricular hemodynamics during exercise in rodents with diastolic dysfunction, establishing a platform to evaluate both the mechanisms of exercise intolerance as well as potential therapeutic approaches to rescue exercise capacity. Acknowledgement/Funding MyoKardia

Altered sensitivity of chronic diabetic rat heart to calcium

1983 ◽  
Vol 245 (6) ◽  
pp. E560-E567 ◽  
Author(s):  
D. R. Bielefeld ◽  
C. S. Pace ◽  
B. R. Boshell
Keyword(s):  
Rat Heart ◽  
Calcium Metabolism ◽  
Left Ventricular Pressure ◽  
Calcium Sensitivity ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Diabetic Rat ◽  
Isolated Hearts ◽  
Pressure Development

An alteration in calcium metabolism in cardiac muscle was observed in diabetic rats 3 mo after streptozotocin treatment. Depression of cardiac output and left ventricular pressure development were more sensitive to decreased extra-cellular calcium in hearts from diabetic than from control animals and occurred within the normal physiological range of freely ionized serum calcium. This decrease in calcium sensitivity was not present after 2 wk of diabetes. In vivo treatment with insulin for 1 mo completely reversed the effect. Addition of octanoate (0.3 mM) to the perfusate of isolated hearts completely reversed the defect, whereas epinephrine (25 nM) only partially reversed it. When the glucose concentration of the perfusate was decreased, the function of diabetic hearts declined and was further diminished at decreasing calcium levels. Hearts from normal rats were unaffected. These results suggest that there is a defect in calcium metabolism or flux in the chronic diabetic rat heart.

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