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Cardiac Late Sodium Channel Current Is a Molecular Target for the Sodium/Glucose Cotransporter 2 Inhibitor Empagliflozin.

ABSTRACT:

Background

SGLT2 (sodium/glucose cotransporter 2) inhibitors exert robust cardioprotective effects against heart failure in patients with diabetes, and there is intense interest to identify the underlying molecular mechanisms that afford this protection. Because the induction of the late component of the cardiac sodium channel current (late-I_Na) is involved in the etiology of heart failure, we investigated whether these drugs inhibit late-I_Na.

Methods

Electrophysiological, in silico molecular docking, molecular, calcium imaging, and whole heart perfusion techniques were used to address this question.

Results

The SGLT2 inhibitor empagliflozin reduced late-I_Na in cardiomyocytes from mice with heart failure and in cardiac Nav1.5 sodium channels containing the long QT syndrome 3 mutations R1623Q or ΔKPQ. Empagliflozin, dapagliflozin, and canagliflozin are all potent and selective inhibitors of H₂O₂-induced late-I_Na (half maximal inhibitory concentration = 0.79, 0.58, and 1.26 µM, respectively) with little effect on peak sodium current. In mouse cardiomyocytes, empagliflozin reduced the incidence of spontaneous calcium transients induced by the late-I_Na activator veratridine in a similar manner to tetrodotoxin, ranolazine, and lidocaine. The putative binding sites for empagliflozin within Nav1.5 were investigated by simulations of empagliflozin docking to a three-dimensional homology model of human Nav1.5 and point mutagenic approaches. Our results indicate that empagliflozin binds to Nav1.5 in the same region as local anesthetics and ranolazine. In an acute model of myocardial injury, perfusion of isolated mouse hearts with empagliflozin or tetrodotoxin prevented activation of the cardiac NLRP3 (nuclear-binding domain-like receptor 3) inflammasome and improved functional recovery after ischemia.

Conclusions

Our results provide evidence that late-I_Na may be an important molecular target in the heart for the SGLT2 inhibitors, contributing to their unexpected cardioprotective effects.

SUBMITTER: Philippaert K

PROVIDER: S-EPMC8154177 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background: Sodium-glucose cotransporter-2 (SGLT2) inhibitors have been shown to decrease the adverse cardiac events and risks of cardiovascular mortality among patients with or without diabetes, which has made these drugs promising treatment options for patients with chronic heart failure. Cardiac dysfunction is a common and severe side effect induced by cancer chemotherapies, which seriously affects the prognosis and life quality of tumor patients. However, it is not clear whether SGLT2 inhibitors have cardiovascular benefits in patients with cancer chemotherapy-related cardiac dysfunction. We aimed to determine whether empagliflozin (EMPA), an SGLT2 inhibitor, has a protective role against sunitinib (SNT)-induced cardiac dysfunction in a mouse model. Methods: Male C57BL/6J mice were randomized into control (control, n = 8), empagliflozin (EMPA, n = 8), sunitinib (SNT, n = 12), or sunitinib and empagliflozin coadministration (SNT + EMPA, n = 12) groups. EMPA, SNT, or SNT-combined EMPA was given via oral gavage for consecutive 28 days. Cardiovascular functions and pathological changes were examined, and the underlying mechanisms of EMPA's effects were investigated in H9c2 cardiomyocytes. Results: Mice in the SNT group exhibited dramatically elevated blood pressure (systolic blood pressure [SBP] 134.30 ± 6.455 mmHg vs. 114.85 ± 6.30 mmHg) and impaired left ventricular function (left ventricular ejection fraction [LVEF] 50.24 ± 3.06% vs. 84.92 ± 2.02%), as compared with those of the control group. However, EMPA could ameliorate SNT-induced cardiotoxicity, both in terms of SBP (117.51 ± 5.28 mmHg vs. 134.30 ± 6.455 mmHg) and LVEF (76.18 ± 5.16% vs. 50.24 ± 3.06 %). In H9c2 cardiomyocytes, SNT-induced cardiomyocyte death and cell viability loss as well as dysfunction of adenosine 5'-monophosphate-activated protein kinase-mammalian target of rapamycin (AMPK-mTOR) signaling-mediated autophagy were restored by EMPA. However, these favorable effects mediated by EMPA were blocked by the inhibition of AMPK or autophagy. Conclusion: EMPA could ameliorate SNT-induced cardiac dysfunction via regulating cardiomyocyte autophagy, which was mediated by the AMPK-mTOR signaling pathway. These findings supported that SGLT2 inhibitor therapy could be a potential cardioprotective approach for cardiovascular complications among patients receiving SNT. However, these favorable effects still need to be validated in clinical trials.

Project description:AimsImpairment of vascular function contributes to the progression of chronic heart failure (HF) by increasing the afterload. Treatment with selective sodium-glucose cotransporter 2 (SGLT2) inhibitors improves the prognosis of HF, but the precise mechanisms remain unclear. The aim of this study was to analyse the effect of empagliflozin on vascular function in patients with HF.Methods and resultsIn an investigator initiated, double-blind, randomized, placebo-controlled, parallel-group, clinical study, patients with HF NYHA II-III and an ejection fraction of 49% or less were randomized 2:1 to receive empagliflozin 10 mg once daily or placebo for 3 months. A total of 74 patients (15% female), aged 66 ± 9 years, with a mean ejection fraction of 39 ± 8% and a median NTproBNP of 558 pg/mL (IQR 219-1051 pg/mL), were included. Vascular parameters such as central systolic blood pressure (cSBP), central pulse pressure (cPP), forward (FPH), and reflected pressure pulse height (RPH) decreased under resting conditions after 1 and 3 months (1 month: cSBP -6.4 ± 8.3 mmHg, P < 0.001, cPP -3.0 ± 6.6 mmHg, P = 0.004, FPH -2.5 ± 4.5 mmHg, P = 0.001, RPH -1.6 ± 3.0 mmHg, P = 0.001; 3 months: cSBP -4.6 ± 8.4 mmHg, P = 0.001, cPP -3.1 ± 4.8 mmHg, P < 0.001, FPH -1.7 ± 3.7 mmHg, P = 0.004, RPH -1.4 ± 2.5 mmHg, P = 0.001) in patients treated with empagliflozin (n = 45). In accordance, cSBP and cPP decreased in patients with empagliflozin treatment under 24 h ambulatory conditions after 1 and 3 months (1 month: cSBP -4.8 ± 10.1 mmHg, P = 0.003, cPP -2.0 ± 5.7 mmHg, P = 0.026; 3 months: cSBP -4.7 ± 9.0 mmHg, P = 0.002, cPP -2.1 ± 6.4 mmHg, P = 0.044). In the placebo group, there was no significant change after 1 and 3 months. The decrease in cSBP under resting conditions (-5.7 ± 2.4 mmHg, P = 0.019) after 1 month and in cSBP (-6.0 ± 2.6, P = 0.027) as well as in pulse wave velocity (-0.5 ± 0.2 m/s, P = 0.021) under 24 h ambulatory conditions after 3 months was greater in the empagliflozin group than in the placebo group.ConclusionsWe found an improvement of vascular function after treatment with empagliflozin that indicates decreased afterload of the left ventricle and may contribute to the beneficial effects of SGLT2 inhibition in HF.