scholarly journals Left Ventricular SGLT1 Protein Expression Correlates with the Extent of Myocardial Nitro-Oxidative Stress in Rats with Pressure and Volume Overload-Induced Heart Failure

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1190
Author(s):  
Alex Ali Sayour ◽  
Mihály Ruppert ◽  
Attila Oláh ◽  
Kálmán Benke ◽  
Bálint András Barta ◽  
...  

Myocardial sodium-glucose cotransporter 1 (SGLT1) has been shown to be upregulated in humans with heart failure (HF) with or without diabetes. In vitro studies have linked SGLT1 to increased nitro-oxidative stress in cardiomyocytes. We aimed to assess the relation between left ventricular (LV) SGLT1 expression and the extent of nitro-oxidative stress in two non-diabetic rat models of chronic heart failure (HF) evoked by either pressure (TAC, n = 12) or volume overload (ACF, n = 12). Sham-operated animals (Sham-T and Sham-A, both n = 12) served as controls. Both TAC and ACF induced characteristic LV structural and functional remodeling. Western blotting revealed that LV SGLT1 protein expression was significantly upregulated in both HF models (both p < 0.01), whereas the phosphorylation of ERK1/2 was decreased only in ACF; AMPKα activity was significantly reduced in both models. The protein expression of the Nox4 NADPH oxidase isoform was increased in both TAC and ACF compared with respective controls (both p < 0.01), showing a strong positive correlation with SGLT1 expression (r = 0.855, p < 0.001; and r = 0.798, p = 0.001, respectively). Furthermore, SGLT1 protein expression positively correlated with the extent of myocardial nitro-oxidative stress in failing hearts assessed by 3-nitrotyrosin (r = 0.818, p = 0.006) and 4-hydroxy-2-nonenal (r = 0.733, p = 0.020) immunostaining. Therefore, LV SGLT1 protein expression was upregulated irrespective of the nature of chronic hemodynamic overload, and correlated significantly with the expression of Nox4 and with the level of myocardial nitro-oxidative stress, suggesting a pathophysiological role of SGLT1 in HF.

2014 ◽  
Vol 306 (10) ◽  
pp. H1453-H1463 ◽  
Author(s):  
Fuzhong Qin ◽  
Deborah A. Siwik ◽  
David R. Pimentel ◽  
Robert J. Morgan ◽  
Andreia Biolo ◽  
...  

Oxidative stress in the myocardium plays an important role in the pathophysiology of hemodynamic overload. The mechanism by which reactive oxygen species (ROS) in the cardiac myocyte mediate myocardial failure in hemodynamic overload is not known. Accordingly, our goals were to test whether myocyte-specific overexpression of peroxisomal catalase (pCAT) that localizes in the sarcoplasm protects mice from hemodynamic overload-induced failure and prevents oxidation and inhibition of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA), an important sarcoplasmic protein. Chronic hemodynamic overload was caused by ascending aortic constriction (AAC) for 12 wk in mice with myocyte-specific transgenic expression of pCAT. AAC caused left ventricular hypertrophy and failure associated with a generalized increase in myocardial oxidative stress and specific oxidative modifications of SERCA at cysteine 674 and tyrosine 294/5. pCAT overexpression ameliorated myocardial hypertrophy and apoptosis, decreased pathological remodeling, and prevented the progression to heart failure. Likewise, pCAT prevented oxidative modifications of SERCA and increased SERCA activity without changing SERCA expression. Thus cardiac myocyte-restricted expression of pCAT effectively ameliorated the structural and functional consequences of chronic hemodynamic overload and increased SERCA activity via a post-translational mechanism, most likely by decreasing inhibitory oxidative modifications. In pressure overload-induced heart failure cardiac myocyte cytosolic ROS play a pivotal role in mediating key pathophysiologic events including hypertrophy, apoptosis, and decreased SERCA activity.


2009 ◽  
Vol 297 (4) ◽  
pp. C928-C934 ◽  
Author(s):  
Changgong Wu ◽  
Lin Yan ◽  
Christophe Depre ◽  
Sunil K. Dhar ◽  
You-Tang Shen ◽  
...  

Cytochrome c oxidase (COX) is composed of 13 subunits, of which COX I, II, and III are encoded by a mitochondrial gene. COX I and II function as the main catalytic components, but the function of COX III is unclear. Because myocardial ischemia affects mitochondrial oxidative metabolism, we hypothesized that COX activity and expression would be affected during postischemic cardiomyopathy. This hypothesis was tested in a monkey model following myocardial infarction (MI) and subsequent pacing-induced heart failure (HF). In this model, COX I protein expression was decreased threefold after MI and fourfold after HF ( P < 0.05 vs. sham), whereas COX II expression remained unchanged. COX III protein expression increased 5-fold after MI and further increased 10-fold after HF compared with sham ( P < 0.05 vs. sham). The physiological impact of COX III regulation was examined in vitro. Overexpression of COX III in mitochondria of HL-1 cells resulted in an 80% decrease in COX I, 60% decrease in global COX activity, 60% decrease in cell viability, and threefold increase in apoptosis ( P < 0.05). Oxidative stress induced by H2O2 significantly ( P < 0.05) increased COX III expression. H2O2 decreased cell viability by 47 ± 3% upon overexpression of COX III, but only by 12 ± 5% in control conditions ( P < 0.05). We conclude that ischemic stress in vivo and oxidative stress in vitro lead to upregulation of COX III, followed by downregulation of COX I expression, impaired COX oxidative activity, and increased apoptosis. Therefore, upregulation of COX III may contribute to the increased susceptibility to apoptosis following MI and subsequent HF.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Shengqi Huo ◽  
Wei Shi ◽  
Haiyan Ma ◽  
Dan Yan ◽  
Pengcheng Luo ◽  
...  

Background. Inflammation and oxidative stress are involved in the initiation and progress of heart failure (HF). However, the role of the IL6/STAT3 pathway in the pressure overload-induced HF remains controversial. Methods and Results. Transverse aortic constriction (TAC) was used to induce pressure overload-HF in C57BL/6J mice. 18 mice were randomized into three groups (Sham, TAC, and TAC+raloxifene, n = 6 , respectively). Echocardiographic and histological results showed that cardiac hypertrophy, fibrosis, and left ventricular dysfunction were manifested in mice after TAC treatment of eight weeks, with aggravation of macrophage infiltration and interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) expression in the myocardium. TAC (four and eight weeks) elevated the phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) and prohibitin2 (PHB2) protein expression. Importantly, IL-6/gp130/STAT3 inhibition by raloxifene alleviated TAC-induced myocardial inflammation, cardiac remodeling, and dysfunction. In vitro, we demonstrated cellular hypertrophy with STAT3 activation and oxidative stress exacerbation could be elicited by IL-6 (25 ng/mL, 48 h) in H9c2 myoblasts. Sustained IL-6 stimulation increased intracellular reactive oxygen species, repressed mitochondrial membrane potential (MMP), decreased intracellular content of ATP, and led to decreased SOD activity, an increase in iNOS protein expression, and increased protein expression of Pink1, Parkin, and Bnip3 involving in mitophagy, all of which were reversed by raloxifene. Conclusion. Inflammation and IL-6/STAT3 signaling were activated in TAC-induced HF in mice, while sustained IL-6 incubation elicited oxidative stress and mitophagy-related protein increase in H9c2 myoblasts, all of which were inhibited by raloxifene. These indicated IL-6/STAT3 signaling might be involved in the pathogenesis of myocardial hypertrophy and HF.


2020 ◽  
Author(s):  
Ada Admin ◽  
Jhih-Yuan Shih ◽  
Yu-Wen Lin ◽  
Sudeshna Fisch ◽  
Juei-Tang Cheng ◽  
...  

Dapagliflozin (DAPA) -- a sodium glucose cotransporter 2 (SGLT2) inhibitor, is approved for treatments of diabetic patients. DAPA-HF trial disclosed its benefits in symptomatic heart failure but the underlying mechanism remains largely unknown. In this longitudinal and prospective study, we investigated changes of left ventricular (LV) functions including speckle tracking in diabetic patients free from symptomatic heart failure post DAPA treatment. Using streptozotocin-induce diabetic rat model, we measured the effects of DAPA on myocardial function. In patients with diabetes, following six months of DAPA, despite no significant changes LV ejection fraction, the diastolic function and longitudinal strain improved. Likewise, compared to control, the diabetic rat heart developed pronounced fibrosis, a decline in strain and overall hemodynamics, all of which were mitigated by DAPA treatment. In contrast, despite insulin exerting a glucose lowering effect, it failed to improve myocardial function and fibrosis. In our in vitro study, under high glucose cardiomyocytes showed significant activations of apoptosis, reactive oxygen species and ER stress associated proteins, which were attenuated by the co-incubation of DAPA. Mechanistically, DAPA suppressed ER stress, reduced myocardial fibrosis and improved overall function. The results can lead to further improvement in management of LV function in diabetic patients.


2020 ◽  
Author(s):  
Ada Admin ◽  
Jhih-Yuan Shih ◽  
Yu-Wen Lin ◽  
Sudeshna Fisch ◽  
Juei-Tang Cheng ◽  
...  

Dapagliflozin (DAPA) -- a sodium glucose cotransporter 2 (SGLT2) inhibitor, is approved for treatments of diabetic patients. DAPA-HF trial disclosed its benefits in symptomatic heart failure but the underlying mechanism remains largely unknown. In this longitudinal and prospective study, we investigated changes of left ventricular (LV) functions including speckle tracking in diabetic patients free from symptomatic heart failure post DAPA treatment. Using streptozotocin-induce diabetic rat model, we measured the effects of DAPA on myocardial function. In patients with diabetes, following six months of DAPA, despite no significant changes LV ejection fraction, the diastolic function and longitudinal strain improved. Likewise, compared to control, the diabetic rat heart developed pronounced fibrosis, a decline in strain and overall hemodynamics, all of which were mitigated by DAPA treatment. In contrast, despite insulin exerting a glucose lowering effect, it failed to improve myocardial function and fibrosis. In our in vitro study, under high glucose cardiomyocytes showed significant activations of apoptosis, reactive oxygen species and ER stress associated proteins, which were attenuated by the co-incubation of DAPA. Mechanistically, DAPA suppressed ER stress, reduced myocardial fibrosis and improved overall function. The results can lead to further improvement in management of LV function in diabetic patients.


1998 ◽  
Vol 76 (6) ◽  
pp. 613-620 ◽  
Author(s):  
Marian Turcani ◽  
Ruthard Jacob

To test the ability of the heart to express characteristic geometric features of concentric and eccentric hypertrophy concurrently, constriction of the ascending aorta was performed in 4-week-old rats. Simultaneously, these rats were treated with an arteriolar dilator minoxidil. An examination 6 weeks after induction of the hemodynamic overload revealed no signs of congestion in systemic or pulmonary circulation in rats with aortic constriction or minoxidil-treated sham-operated rats. The magnitude of hemodynamic overload caused by aortic constriction or minoxidil treatment could be considered as equivalent, because the same enlargement of left ventricular pressure-volume area was necessary to compensate for either pressure or volume overload. Myocardial contractility decreased in rats with aortic constriction, and the compensation was achieved wholly by the marked concentric hypertrophy. Volume overload in minoxidil-treated rats was compensated partially by the eccentric hypertrophy and partially by the increased myocardial contractility. In contrast, increased lung weight and pleural effusion were found in all minoxidil-treated rats with aortic constriction. Unfavorable changes in left ventricular mass and geometry, relatively high chamber stiffness, and depressed ventricular and myocardial function were responsible for the massive pulmonary congestion.Key words: cardiac hypertrophy, heart failure, pressure overload, volume overload, minoxidil.


2020 ◽  
Author(s):  
Ada Admin ◽  
Jhih-Yuan Shih ◽  
Yu-Wen Lin ◽  
Sudeshna Fisch ◽  
Juei-Tang Cheng ◽  
...  

Dapagliflozin (DAPA) -- a sodium glucose cotransporter 2 (SGLT2) inhibitor, is approved for treatments of diabetic patients. DAPA-HF trial disclosed its benefits in symptomatic heart failure but the underlying mechanism remains largely unknown. In this longitudinal and prospective study, we investigated changes of left ventricular (LV) functions including speckle tracking in diabetic patients free from symptomatic heart failure post DAPA treatment. Using streptozotocin-induce diabetic rat model, we measured the effects of DAPA on myocardial function. In patients with diabetes, following six months of DAPA, despite no significant changes LV ejection fraction, the diastolic function and longitudinal strain improved. Likewise, compared to control, the diabetic rat heart developed pronounced fibrosis, a decline in strain and overall hemodynamics, all of which were mitigated by DAPA treatment. In contrast, despite insulin exerting a glucose lowering effect, it failed to improve myocardial function and fibrosis. In our in vitro study, under high glucose cardiomyocytes showed significant activations of apoptosis, reactive oxygen species and ER stress associated proteins, which were attenuated by the co-incubation of DAPA. Mechanistically, DAPA suppressed ER stress, reduced myocardial fibrosis and improved overall function. The results can lead to further improvement in management of LV function in diabetic patients.


2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
BK Lakatos ◽  
M Ruppert ◽  
M Tokodi ◽  
A Olah ◽  
S Braun ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: None. Speckle-tracking echocardiography (STE)-derived global longitudinal strain (GLS) is considered to be a sensitive marker of left ventricular (LV) function in a wide variety of cardiovascular diseases. Still, evidence suggests that GLS is significantly influenced by loading conditions. Myocardial work index (MWI) evaluates myocardial deformation in the context of afterload through the interpretation of strain in relation to instantaneous LV pressure. MWI may potentially overcome the limitations of mere strain calculation, and may better reflect cardiac contractility in hemodynamic overload states. Accordingly, our aim was to examine the relationship of GLS and MWI with load-independent markers of LV contractility in rat models of pressure- and volume overload-induced heart failure. Male Wistar rats underwent transverse aortic constriction (TAC; n = 12) to generate LV pressure overload, or aortocaval fistula (ACF; n = 12) was established to induce severe LV volume overload. In case of the control groups, sham procedures were performed (n = 12/12). Echocardiography loops were obtained to determine STE-derived GLS and global MWI. Pressure-volume analysis with transient occlusion of the inferior vena cava was carried out to calculate preload recruitable stroke work (PRSW), as a load-independent „gold-standard" parameter of LV contractility. GLS was mildly reduced in the ACF group (-13.2 ± 2.4 vs. -15.4 ± 2.0%, p &lt; 0.05), while it was significantly lower in TAC group compared to controls (-7.0 ± 2.8 vs. -14.5 ± 2.5%; p &lt; 0.001). In contrast with these findings, PRSW and also MWI were significantly reduced in ACF (58 ± 14 vs. 111 ± 40 mmHg; 1328 ± 411 vs. 1934 ± 308 mmHg%, both p &lt; 0.01), however, they were comparable between TAC and the corresponding sham group (110 ± 26 vs. 116 ± 68 mmHg; 1687 ± 275 Hgmm% vs. 1537 ± 662 Hgmm%; both p = NS). In the pooled population, GLS did not show relationship with PRSW (r=-0.23; p = 0.12), while MWI showed significant correlation with it (r = 0.70; p &lt; 0.001). GLS is significantly influenced by loading conditions, therefore, in case of severe pressure- or volume overload it may not be a reliable marker of LV contractility. In our rat model of pressure overload induced heart failure, contractility was maintained despite decreased GLS, while in the model of volume overload induced heart failure, GLS was maintained despite decreased contractility. MWI reflects contractility in hemodynamic overload states, therefore, it may be a more suitable marker of systolic function. Abstract Figure. Pressure-strain loops of the groups


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Alex Ali Sayour ◽  
Attila Oláh ◽  
Mihály Ruppert ◽  
Bálint András Barta ◽  
Eszter Mária Horváth ◽  
...  

Abstract Background Whereas selective sodium-glucose cotransporter 2 (SGLT2) inhibitors consistently showed cardiovascular protective effects in large outcome trials independent of the presence of type 2 diabetes mellitus (T2DM), the cardiovascular effects of dual SGLT1/2 inhibitors remain to be elucidated. Despite its clinical relevance, data are scarce regarding left ventricular (LV) SGLT1 expression in distinct heart failure (HF) pathologies. We aimed to characterize LV SGLT1 expression in human patients with end-stage HF, in context of the other two major glucose transporters: GLUT1 and GLUT4. Methods Control LV samples (Control, n = 9) were harvested from patients with preserved LV systolic function who went through mitral valve replacement. LV samples from HF patients undergoing heart transplantation (n = 71) were obtained according to the following etiological subgroups: hypertrophic cardiomyopathy (HCM, n = 7); idiopathic dilated cardiomyopathy (DCM, n = 12); ischemic heart disease without T2DM (IHD, n = 14), IHD with T2DM (IHD + T2DM, n = 11); and HF patients with cardiac resynchronization therapy (DCM:CRT, n = 9, IHD:CRT, n = 9 and IHD-T2DM:CRT, n = 9). We measured LV SGLT1, GLUT1 and GLUT4 gene expressions with qRT-PCR. The protein expression of SGLT1, and activating phosphorylation of AMP-activated protein kinase (AMPKα) and extracellular signal-regulated kinase 1/2 (ERK1/2) were quantified by western blotting. Immunohistochemical staining of SGLT1 was performed. Results Compared with controls, LV SGLT1 mRNA and protein expressions were significantly and comparably upregulated in HF patients with DCM, IHD and IHD + T2DM (all P < 0.05), but not in HCM. LV SGLT1 mRNA and protein expressions positively correlated with LVEDD and negatively correlated with EF (all P < 0.01). Whereas AMPKα phosphorylation was positively associated with SGLT1 protein expression, ERK1/2 phosphorylation showed a negative correlation (both P < 0.01). Immunohistochemical staining revealed that SGLT1 expression was predominantly confined to cardiomyocytes, and not fibrotic tissue. Overall, CRT was associated with reduction of LV SGLT1 expression, especially in patients with DCM. Conclusions Myocardial LV SGLT1 is upregulated in patients with HF (except in those with HCM), correlates significantly with parameters of cardiac remodeling (LVEDD) and systolic function (EF), and is downregulated in DCM patients with CRT. The possible role of SGLT1 in LV remodeling needs to be elucidated.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M Ruppert ◽  
B.K Lakatos ◽  
M Tokodi ◽  
C Karime ◽  
I Hizoh ◽  
...  

Abstract Background Two-dimensional (2D) speckle tracking echocardiography (STE)-derived myocardial strain parameters are sensitive markers of left ventricular (LV) systolic function. Novel findings suggest that the contractile state of the myocardium, afterload and preload are major determinants of STE measurements. However, the hypothesis that longitudinal strain expresses the interaction between contractility and loading conditions rather than contractility alone in hemodynamic overload-induced heart failure (HF) has not been tested. Purpose This study aimed to explore the connection between longitudinal strain and contractility, afterload and preload in rat models of pressure overload (PO)- and volume overload (VO)-induced heart failure (HF). Methods Pressure overload (PO)-induced HF was evoked by transverse aortic constriction ([TAC], n=14). Volume overload (VO)-induced HF was established by an aortocaval fistula ([ACF], n=12). Age-matched sham operated animals served as controls. Pressure-volume analysis was carried out to compute cardiac contractility (slope of end-systolic pressure-volume relationship [ESPVR]), afterload (arterial elastance [Ea]) and ventriculo-arterial coupling ([VAC] = Ea/ESPVR). Preload was evaluated by meridional end-diastolic wall stress (σend-diastolic). STE was performed to assess global longitudinal strain (GLS). Results GLS was impaired in both PO-induced HF (−5.9±0.6 vs. −12.9±0.5%, TAC vs Sham, P&lt;0.001) and VO-evoked HF (−11.7±0.7 vs. −13.5±0.4%, ACF vs Sham, P=0.048). Hemodynamic measurements indicated that the TAC group presented with maintained ESPVR, increased Ea and enhanced σend-diastolic. In contrast, the ACF group was characterized by reduced ESPVR, decreased Ea and enhanced σend-diastolic. Ordinary least squares non-linear regression revealed that GLS was predominantly determined by afterload (Ea) in the TAC model and by contractility (ESPVR) in the ACF model. In accordance, GLS showed a strong correlation with Ea in case of PO-induced HF (R= 0.848, P&lt;0.001) and with ESPVR in case of VO-evoked HF (R=−0.526; P=0.008), respectively. Furthermore, GLS also demonstrated strong correlation with VAC in both the TAC and the ACF models. Of particular interest, a robust correlation between VAC and GLS could also be detected in the entire study population (R= 0.654, P&lt;0.001). Conclusion Both afterload and contractility define GLS. Hence, under conditions when both factors become altered, GLS reflects VAC. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): NVKP_16-1-2016-0017


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