Empagliflozin maintains capillarization and improves cardiac function in a murine model of left ventricular pressure overload

Masaaki Nakao,Yung Ting Hsiao,Goro Katsuumi,Yohko Yoshida,Ippei Shimizu,Tohru Minamino,Tomoyoshi Soga,Shujiro Okuda,Yuka Hayashi,Ryutaro Ikegami,Masayoshi Suda

doi:10.1038/s41598-021-97787-2

Abstract

Patients with type 2 diabetes treated with Sodium glucose transporter 2 (SGLT2) inhibitors show reduced mortality and hospitalization for heart failure (HF). SGLT2 inhibitors are considered to activate multiple cardioprotective pathways; however, underlying mechanisms are not fully described. This study aimed to elucidate the underlying mechanisms of the beneficial effects of SGLT2 inhibitors on the failing heart. We generated a left ventricular (LV) pressure overload model in C57BL/6NCrSlc mice by transverse aortic constriction (TAC) and examined the effects of empagliflozin (EMPA) in this model. We conducted metabolome and transcriptome analyses and histological and physiological examinations. EMPA administration ameliorated pressure overload-induced systolic dysfunction. Metabolomic studies showed that EMPA increased citrulline levels in cardiac tissue and reduced levels of arginine, indicating enhanced metabolism from arginine to citrulline and nitric oxide (NO). Transcriptome suggested possible involvement of the insulin/AKT pathway that could activate NO production through phosphorylation of endothelial NO synthase (eNOS). Histological examination of the mice showed capillary rarefaction and endothelial apoptosis after TAC, both of which were significantly improved by EMPA treatment. This improvement was associated with enhanced expression phospho-eNOS and NO production in cardiac endothelial cells. NOS inhibition attenuated these cardioprotective effects of EMPA. The in vitro studies showed that catecholamine-induced endothelial apoptosis was inhibited by NO, arginine, or AKT activator. EMPA activates the AKT/eNOS/NO pathway, which helps to suppress endothelial apoptosis, maintain capillarization and improve systolic dysfunction during LV pressure overload.

Highlights

Patients with type 2 diabetes treated with Sodium glucose transporter 2 (SGLT2) inhibitors show reduced mortality and hospitalization for heart failure (HF)
We re-analyzed the results from our metabolomic studies and found that the arginine level was significantly reduced in the transverse aortic constriction (TAC) + EMPA group compared with the TAC group
This led us to consider that the finding of reduced arginine, together with an increased citrulline level, might suggest an enhanced metabolism from arginine to citrulline plus nitric oxide (NO), which would be indicative of endothelial NO synthase (eNOS) activation

Summary

Introduction

Patients with type 2 diabetes treated with Sodium glucose transporter 2 (SGLT2) inhibitors show reduced mortality and hospitalization for heart failure (HF). In the EMPA-REG, diabetic patients receiving empagliflozin (EMPA) showed lower risk for composite cardiovascular outcome and death from any cause than patients receiving standard diabetes care[1] These findings were confirmed by the Canagliflozin Cardiovascular Assessment Study (CANVAS)[2] and Dapagliflozin Effect on Cardiovascular Events-Thrombolysis in Myocardial Infarction 58 (DECLARE-TIMI 58) trial[3], both of which studied different types of SGLT2 inhibitors. We show that in hearts subjected to LV pressure overload EMPA maintains capillarization by activating the AKT/eNOS/NO pathway in endothelial cells (ECs), which helps to suppress endothelial apoptosis and enhance cardiac systolic function

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