Enhanced Expression and Function of Renal SGLT2 (Sodium-Glucose Cotransporter 2) in Heart Failure: Role of Renal Nerves

Author(s):  
Kenichi Katsurada ◽  
Shyam S. Nandi ◽  
Neeru M. Sharma ◽  
Kaushik P. Patel

Background: Recent clinical studies demonstrate that SGLT2 (sodium-glucose cotransporter 2) inhibitors ameliorate heart failure (HF). The present study was conducted to assess the expression and function of renal SGLT2 and the influence of enhanced renal sympathetic tone in HF. Methods: Four weeks after coronary artery ligation surgery to induce HF, surgical bilateral renal denervation (RDN) was performed in rats. Four groups of rats (Sham-operated control [Sham], Sham+RDN, HF and HF+RDN; n=6/group) were used. Immunohistochemistry and Western blot analysis were performed to evaluate the renal SGLT2 expression. One week after RDN (5 weeks after induction of HF), intravenous injection of SGLT2 inhibitor dapagliflozin were performed to assess renal excretory responses. In vitro, human embryonic kidney cells were used to investigate the fractionation of SGLT2 after norepinephrine treatment. Results: In rats with HF, (1) SGLT2 expression in the proximal tubule of the kidney was increased; (2) the response of increases in urine flow, sodium excretion, and glucose excretion to dapagliflozin were greater; and (3) RDN attenuated renal SGLT2 expression and normalized renal functional responses to dapagliflozin. In vitro, norepinephrine promoted translocation of SGLT2 to the cell membrane. Conclusions: These results indicate that the enhanced tonic renal sympathetic nerve activation in HF increases the expression and functional activity of renal SGLT2. Potentiated trafficking of SGLT2 to cell surface in renal proximal tubules mediated by norepinephrine may contribute to this functional activation of SGLT2 in HF. These findings provide critical insight into the underlying mechanisms for the beneficial effects of SGLT2 inhibitors on HF reported in the clinical studies.

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Jordan Lancaster ◽  
Elizabeth Juneman ◽  
Nicholle Johnson ◽  
Joseph Bahl ◽  
Steven Goldman

Background: Cell-based regenerative therapies hold promise as a new treatment for heart failure. Tissue engineered scaffolds used for cell delivery enhance potential improvements in cardiac function by providing the structural and nutrient support for transplanted cell survival, integration, and re-population of injured tissues. Previously, our laboratory reported improvements in left ventricular (LV) function in rats with chronic heart failure (CHF) after placement of a neonatal cardiomyocyte (NCM) seeded 3-dimensional fibroblast construct (3DFC). In brief, 3 weeks after implantation of the NCM-3DFC, LV function improves by increasing (p<0.05) ejection fraction 26% and cardiac index 33%, while decreasing (p<0.05) LV end diastolic pressure 38%. The current report focuses on NCM survival and LV improvements out to 7 weeks post NCM-3DFC implantation. Methods and Results: Cardiomyocytes were isolated from neonatal rat hearts and seeded onto a 3DFC. We evaluated NCM-3DFC in vitro for cellular organization and the presence of functional gap junctions, which demonstrated extensive cell-to-cell connectivity. At 5 days in culture, the seeded patch contracted spontaneously in a rhythmic and directional fashion, beating at 43±3 beats/min with a mean displacement of 1.3±0.3 mm and contraction velocity of 0.8±0.2 mm/sec. The seeded patch could be electrically paced at near physiological rates (270±30 beats/min) while maintaining coordinated, directional contractions. For in vivo evaluation, rats underwent coronary artery ligation and allowed to recover for 3 weeks to establish CHF. NCM-3DFC were implanted 3 weeks after ligation and evaluated 3 and 7 weeks later (6 and 10 weeks after ligation respectively). Live cell tracking of implanted NCM using Q-Dots revealed ∼9% survival of transplanted cells 3 weeks after implantation. In addition, improvements in LV function continued at 7 weeks after implantation of the NCM-3DFC by increasing (p<0.05) ejection fraction 37%. Conclusion: A multicellular, electromechanically organized, cardiomyocyte scaffold, engineered in vitro can improve LV function when implanted directly on the hearts of rats with CHF; the transplanted cells survive and improve LV function chronically.


Blood ◽  
2016 ◽  
Vol 127 (14) ◽  
pp. 1743-1751 ◽  
Author(s):  
Jesse W. Rowley ◽  
Stéphane Chappaz ◽  
Aurélie Corduan ◽  
Mark M. W. Chong ◽  
Robert Campbell ◽  
...  

Key Points Dicer1 deletion in MKs alters platelet miRNA and mRNA profiles. Dicer1-deficient platelets display increased integrins αIIb and β3 levels and enhanced in vitro and in vivo functional responses.


2020 ◽  
Vol 11 ◽  
pp. 204062232097483
Author(s):  
Qing-Qing Zhang ◽  
Guo-Qing Li ◽  
Yi Zhong ◽  
Jie Wang ◽  
An-Ning Wang ◽  
...  

Background: Chronic exposure to excess glucocorticoids is frequently associated with a specific cardiomyopathy. Empagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, has beneficial effects as it aids in the reduction of heart failure and cardiovascular mortality in hospitalized patients. The aim of this study was to investigate the effects of empagliflozin on chronic hypercortisolism-induced myocardial fibrosis and myocardial dysfunction in mice. Methods: Male C57BL/6J mice (6 weeks old) were randomized to control, corticosterone (CORT), and empagliflozin + CORT groups. After 4 weeks of administration, heart structure and function were evaluated by echocardiography, and peripheral blood and tissue samples were collected. Expressions of Ccl2, Itgax, Mrc1, and Adgre1 mRNA in heart tissue were evaluated by RT-PCR, and signal transducer and activator of transcription 3 (STAT3) and Toll-like receptor 4 (TLR4) protein expression were analyzed by Western blotting. Results: Empagliflozin effectively reduced body weight, liver triglyceride, visceral adipose volume, and uric acid in CORT-treated mice. Left ventricular hypertrophy and cardiac dysfunction were improved significantly, phosphorylated STAT3 and TLR4 were alleviated, and macrophage infiltration in the myocardium was inhibited after administration of empagliflozin in CORT-treated mice. Conclusion: Empagliflozin has beneficial effects on specific cardiomyopathy associated with CORT, and the results provide new evidence that empagliflozin might be a potential drug for the prevention of this disease.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
H Kondo ◽  
I Akoumianakis ◽  
N Akawi ◽  
M Cristina ◽  
L Herdman ◽  
...  

Abstract Background Sodium glucose cotransporter 2 (SGLT2) inhibitors are antidiabetic drugs that control plasma glucose levels by inhibiting reabsorption of glucose in kidney. Recent clinical trials have suggested a class effect of SGLT2 inhibitors in preventing hospitalization due to heart failure. However, the underlying mechanism has not been fully elucidated. Purpose We investigated the direct effect of the SGLT2 inhibitor, Canagliflozin (Cana), on myocardial redox state in humans. Methods The study included 48 patients undergoing cardiac surgery. Fresh myocardial tissues were incubated ex vivo with or without Cana and then used for superoxide quantification and Western immunoblotting. NADPH-oxidases activity was evaluated with NADPH 100μM stimulation, while nitric oxide synthase (NOS) coupling was assessed by using N(ω)-nitro-L-arginine methyl ester (L-NAME, a NOS inhibitor). A human cardiomyocyte (HCM) cell line was also used for in vitro validation of the effects of Cana on myocardium. Results Ex vivo incubation of myocardium with Cana significantly reduced baseline (A) and NADPH-oxidase-derived O2·− (B) and improved NOS coupling reflected by positive L-NAME delta O2·− values (C). Regulation of NADPH-oxidases activity by Cana was found to result from reduced GTP-activation (D) and consequent membrane translocation (E) of Rac1, a key subunit of NADPH-oxidases. Cana also reduced tetrahydrobiopterin (BH4) oxidation, increasing its bioavailability (F), which is a key mechanism to improve NOS coupling. Incubation with Cana enhanced phosphorylation of AMPK, and the downstream signalling, ACC (not shown). Additional Compound C, which is inhibitor of AMPK, significantly reversed these effects of Cana (A, B, C, D, E, F). These findings were replicated in HCM (not shown). In line with these, Cana increased the ADP/ATP ratio of cytoplasm in HCM, which could provide an upstream mechanism for AMPK activation. Conclusions We demonstrate for the first time in humans, that Cana suppresses myocardial NADPH-oxidases activity and improves NOS coupling through an AMPK-mediated pathway. This could be an underlying mechanism for the cardioprotective effects of SGLT2 inhibitors.


2011 ◽  
Vol 2 (1) ◽  
pp. 12 ◽  
Author(s):  
Ann Brasey ◽  
Raouf Igue ◽  
Loubna Djemame ◽  
Serge Séguin ◽  
Paolo Renzi ◽  
...  

<p>Antisense oligonucleotides (AON) delivered via inhalation are in drug development for respiratory diseases. In rodents and monkeys, repeated exposure to high doses of inhaled phosphorothioate (PS) AON can lead to microscopic changes in the lungs, including accumulation of alveolar macrophages in the lower airway that have a <em>foamy</em> appearance. The functional consequences that result from this morphological change are unclear as there is controversy whether the vacuoles/inclusion bodies reflect normal clearance of the inhaled AON or are early indicators of lung toxicity. The morphological and functional responses of macrophage to PS AON were characterized <em>in vitro</em> using the comparator drug amiodarone, as a known inducer of foamy macrophages. Morphological changes of increased vacuolization with the presence of lamellated structures were observed in macrophages in response to both amiodarone and AON treatment. Functional responses to the drugs clearly differed with amiodarone treatment leading to apoptosis of cells and cell death, release of proinflammatory mediators IL-1RA, MIP-1<em>α </em>and TNF<em>α</em>, decrease in IP-10, a cytokine shown to be involved in protection against pulmonary fibrosis and altered phagocytosis capacity of the cells. In contrast, AON in concentrations up to 30 μM, had no effect on cell viability or apoptosis, had minimal effects on pro-inflammatory cytokines, increased IP-10 levels and did not alter the phagocytic capacity of the cells. Exposure of macrophages to AON<em> in vitro</em>, led to morphological changes of increased vacuolization, but did not lead to functional consequences which were observed with another vacuolization-inducing drug, suggesting that the <em>in vivo </em>phenotypic changes observed following inhalation of AON may be consistent with a clearance mechanism and not an activation or impairment of macrophages.</p>


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
O Horvath ◽  
L Deres ◽  
K Ordog ◽  
K Bruszt ◽  
B Sumegi ◽  
...  

Abstract Introduction The deterioration of mitochondrial quality control greatly contributes to the hypertension induced cardiac remodeling and progression of heart failure. Our previous in vitro results demonstrated the mitochondrial protective effect of antioxidant BGP-15 compound in the presence of cellular stress. Purpose In our recent study we investigated the effect of BGP-15 on cardiac remodeling in spontaneously hypertensive rats (SHR) with manifested heart failure and on mitochondrial dynamics and function in cell culture model. Methods 15-month-old male SHR received 25 mg/kg/day BGP-15 (SHR-B) or placebo (SHR-C) for 18 weeks. Age matched Wistar rats (WKY) were used as normotensive control. The heart function was monitored by echocardiography. Histological preparations were made from cardiac tissue. Neonatal rat cardiomyocytes (NRCMs) were used as in vitro model. 150 μM H2O2 stress and 50 μM BGP-15 treatment was applied. Mitochondrial network was stained with MitoTracker Red. Mitochondrial membrane potential was detected using JC-1 dye, while mitochondrial function was monitored by the Agilent Seahorse XFp, Cell Mito Stress Test. In both model the cellular levels of mitochondrial dynamics proteins were measured in Western blot. To study the ultrastructure we used electron microscopy in our in vivo and in vitro model. Results Left ventricular (LV) mass and LV wall thickness were increased significantly in SHR-C group compared to the initial values (p<0.05). These parameters were decreased considerably in the SHR-B group. Ejection fraction (EF%) decreased in both SHR group although this downturn was minimal because of the treatment. Chronic high blood pressure caused higher collagen deposition in SHR-C rats that was significantly diminished in the SHR-B group. Regarding the mitochondrial function decrease in the levels of fusion proteins OPA1 and MFN2 was observed in the SHR-C group. These differences were significantly reduced by BGP-15 treatment (p<0.05). Mitigation of the level of fission protein DRP1 was however reduced by BGP-15 (p<0.05). In our cellular model, we observed that the H2O2-induced mitochondrial fragmentation was decreased by BGP-15 treatment (p<0.05). BGP-15 treatment prevented mitochondrial membrane potential fall in H2O2 stress (p<0.05). There was no significant difference in basal respiration among groups by monitoring the mitochondrial function. The maximal respiration capacity and ATP production were significantly higher in the BGP-15 treated group in comparison to the stressed group (p<0.05). Conclusion BGP-15 treatment has beneficial effects on mitochondrial dynamics and structure by promoting fusion processes. It also supports the maintenance of mitochondrial function through the preservation of the mitochondrial structure. The mitigation of remodeling processes and the preserved EF in the treated group are results at least partly of the comprehensible effects of BGP-15 on mitochondrial structure and function. Acknowledgement/Funding GINOP-2.3.2-15-2016-00049; GINOP-2.3.2-15-2016-00048; GINOP-2.3.3-15-2016-00025


2021 ◽  
Author(s):  
Yuze Zhang ◽  
Xiaoyan Lin ◽  
Yong Chu ◽  
Xiaoming Chen ◽  
Heng Du ◽  
...  

Abstract Background:Cardiac remodeling is one of the major risk factors for heart failure. In patients with type 2 diabetes, sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of the first hospitalization for heart failure, possibly through glucose-independent mechanisms, but the underlying mechanisms remain largely unknown. This study aimed to shed light on the efficacy of dapagliflozin in reducing cardiac remodeling and potential mechanisms.Methods:Sprague-Dawley (SD) rats, induced by chronic infusion of Angiotensin II (Ang II) at a dose of 520 ng/kg per minute for 4 weeks with ALZET® mini-osmotic pumps, were treated with either SGLT2 inhibitor dapagliflozin (DAPA) or vehicle alone. Echocardiography was performed to determine cardiac structure and function. Cardiac fibroblasts (CFs) were treated with Ang II with or without the indicated concentration of DAPA. The protein levels of collagen and TGF-β1/Smad signaling were measured along with body weight, and blood biochemical indexes.Results:DAPA treatment resulted in the amelioration of left ventricular dysfunction in Ang II-infused SD rats without affecting blood glucose and blood pressure. Myocardial hypertrophy, fibrosis and increased collagen synthesis caused by Ang II infusion were significantly inhibited by DAPA treatment. In vitro, DAPA inhibit the Ang II-induced collagen production of CFs. Immunoblot with heart tissue homogenates from chronic Ang II-infused rats revealed that DAPA inhibited the activation of TGF-β1/Smads signaling.Conclusion:DAPA ameliorates Ang II-induced cardiac remodeling by regulating the TGF-β1/Smad signaling in a glucose-independent manner. DAPA may serve as a novel therapy for pathological cardiac remodeling.


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 (18) ◽  
pp. 9852
Author(s):  
Alex Ali Sayour ◽  
Mihály Ruppert ◽  
Attila Oláh ◽  
Kálmán Benke ◽  
Bálint András Barta ◽  
...  

Selective sodium–glucose cotransporter 2 (SGLT2) inhibitors reduced the risk of hospitalization for heart failure in patients with or without type 2 diabetes (T2DM) in large-scale clinical trials. The exact mechanism of action is currently unclear. The dual SGLT1/2 inhibitor sotagliflozin not only reduced hospitalization for HF in patients with T2DM, but also lowered the risk of myocardial infarction and stroke, suggesting a possible additional benefit related to SGLT1 inhibition. In fact, several preclinical studies suggest that SGLT1 plays an important role in cardiac pathophysiological processes. In this review, our aim is to establish the clinical significance of myocardial SGLT1 inhibition through reviewing basic research studies in the context of SGLT2 inhibitor trials.


2020 ◽  
Vol 25 (5) ◽  
pp. 3870
Author(s):  
Zh. D. Kobalava ◽  
V. V. Medovchshikov ◽  
N. B. Yeshniyazov

Patients with heart failure with reduced ejection fraction (HFrEF), despite optimal evidence-based treatment, have a high residual risk of adverse outcomes. The favorable results of studies on cardiovascular safety and the effectiveness of sodium-glucose cotransporter 2 (SGLT2) inhibitors in patients with type 2 diabetes (T2D), including outcomes associated with heart failure, were the reason for studying the effectiveness in patients with HFrEF regardless of the T2D status. For the first time in the DAPA-HF study, the SGLT2 inhibitor dapagliflozin in patients with HFrEF showed a positive effect on hard endpoints. Data of the secondary analysis confirmed the effectiveness of dapagliflozin regardless of the T2D status, therapy, age, and quality of life. The results of DAPA-HF have become a serious statement for changing the standards of the guideline-recommended therapy of HFrEF.


Sign in / Sign up

Export Citation Format

Share Document