Obesity contributes 65-75% of the risk for human primary (essential) hypertension which is a major driver of cardiovascular and kidney diseases. Kidney dysfunction, associated with increased renal sodium reabsorption and compensatory glomerular hyperfiltration, plays a key role in initiating obesity-hypertension and target organ injury. Mediators of kidney dysfunction and increased blood pressure include 1) elevated renal sympathetic nerve activity (RSNA); 2) increased antinatriuretic hormones such as angiotensin II and aldosterone; 3) relative deficiency of natriuretic hormones; 4) renal compression by fat in and around the kidneys; 5) activation of innate and adaptive immune cells that invade tissues throughout the body, producing inflammatory cytokines/chemokines that contribute to vascular and target organ injury, and exacerbate hypertension. These neurohormonal, renal, and inflammatory mechanisms of obesity-hypertension are interdependent. For example, excess adiposity increases the adipocyte-derived cytokine leptin which increases RSNA by stimulating the central nervous system proopiomelanocortin-melanocortin 4 receptor pathway. Excess visceral, perirenal and renal sinus fat compress the kidneys which, along with increased RSNA, contribute to renin-angiotensin-aldosterone system activation, although obesity may also activate mineralocorticoid receptors independent of aldosterone. Prolonged obesity, hypertension, metabolic abnormalities, and inflammation cause progressive renal injury, making hypertension more resistant to therapy and often requiring multiple antihypertensive drugs and concurrent treatment of dyslipidemia, insulin resistance, diabetes, and inflammation. More effective anti-obesity drugs are needed to prevent the cascade of cardiorenal, metabolic, and immune disorders that threaten to overwhelm health care systems as obesity prevalence continues to increase.

Background We determined if the sodium glucose co‐transporter 2 inhibitor empagliflozin attenuates pressure overload‐induced heart failure in non‐diabetic mellitus mice by direct cardiac effects and the mechanisms involved. Methods and Results Male C57BL/6J mice (4–6 months of age) were subjected to sham surgeries or transverse aortic constriction to produce cardiac pressure overload. Two weeks after transverse aortic constriction, empagliflozin (10 mg/kg per day) or vehicle was administered daily for 4 weeks. Empagliflozin increased survival rate and significantly attenuated adverse left ventricle remodeling and cardiac fibrosis after transverse aortic constriction. Empagliflozin also attenuated left ventricular systolic and diastolic dysfunction, evaluated by echocardiography, and increased exercise endurance by 36% in mice with transverse aortic constriction‐induced heart failure. Empagliflozin significantly increased glucose and fatty acid oxidation in failing hearts, while reducing glycolysis. These beneficial cardiac effects of empagliflozin occurred despite no significant changes in fasting blood glucose, body weight, or daily urine volume. In vitro experiments in isolated cardiomyocytes indicated that empagliflozin had direct effects to improve cardiomyocyte contractility and calcium transients. Importantly, molecular docking analysis and isolated perfused heart experiments indicated that empagliflozin can bind cardiac glucose transporters to reduce glycolysis, restore activation of adenosine monophosphate‐activated protein kinase and inhibit activation of the mammalian target of rapamycin complex 1 pathway. Conclusions Our study demonstrates that empagliflozin may directly bind glucose transporters to reduce glycolysis, rebalance coupling between glycolysis and oxidative phosphorylation, and regulate the adenosine monophosphate‐activated protein kinase mammalian target of rapamycin complex 1 pathway to attenuate adverse cardiac remodeling and progression of heart failure induced by pressure‐overload in non‐diabetic mellitus mice.

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Clinical trials showed that sodium-glucose cotransporter 2 (SGLT2) inhibitors, a class of drugs developed for treating diabetes mellitus, improve prognosis of patients with heart failure (HF). However, the mechanisms for cardioprotection by SGLT2 inhibitors are still unclear. Mitochondrial dysfunction and oxidative stress play important roles in progression of HF. This study tested the hypothesis that empagliflozin (EMPA), a highly selective SGLT2 inhibitor, improves mitochondrial function and reduces reactive oxygen species (ROS) while enhancing cardiac performance through direct effects on the heart in a non-diabetic mouse model of HF induced by transverse aortic constriction (TAC). EMPA or vehicle was administered orally for 4 weeks starting 2 weeks post-TAC. EMPA treatment did not alter blood glucose or body weight but significantly attenuated TAC-induced cardiac dysfunction and ventricular remodeling. Impaired mitochondrial oxidative phosphorylation (OXPHOS) in failing hearts was significantly improved by EMPA. EMPA treatment also enhanced mitochondrial biogenesis and restored normal mitochondria morphology. Although TAC increased mitochondrial ROS and decreased endogenous antioxidants, EMPA markedly inhibited cardiac ROS production and upregulated expression of endogenous antioxidants. In addition, EMPA enhanced autophagy and decreased cardiac apoptosis in TAC-induced HF. Importantly, mitochondrial respiration significantly increased in ex vivo cardiac fibers after direct treatment with EMPA. Our results indicate that EMPA has direct effects on the heart, independently of reductions in blood glucose, to enhance mitochondrial function by upregulating mitochondrial biogenesis, enhancing OXPHOS, reducing ROS production, attenuating apoptosis, and increasing autophagy to improve overall cardiac function in a non-diabetic model of pressure overload-induced HF.

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