MYOCARDIAL REDUCTION OF SYMPATHETIC ACTIVITY IS INVOLVED IN THE ANTIFIBROTIC AND ANTIHYPERTROPHIC EFFECTS OF SGLT2 INHIBITION IN ANGIOTENSIN II-DEPENDENT HYPERTENSION

Abstract

Objective: The beneficial myocardial effects of SGLT2 inhibitors, a new class of antidiabetic drugs, have been described not only in diabetic patients, but also in heart diseases not associated with diabetes. The positive effects of these drugs go beyond glycemic control and involve multiple mechanisms. In the present study we investigate whether the cardioprotective effects of empagliflozin, a SGLT2 inhibitor, may be dependent on myocardial sympathetic activity in experimental model of angiotensin II-dependent hypertension. Design and method: Experiments were performed in Sprague Dawley rats (n = 26) followed for 4 weeks and divided in the following groups: a) Angiotensin II-treated group (Ang II, 200 ng/kg/min, osmotic minipumps s.c, n = 7); b) Ang II +Empagliflozin-treated group (Empa, 10 mg/kg/day, per os, n = 6); c) control group (physiological saline s.c., n = 7); d) Control+Empagliflozin-treated group (n = 6). Systolic blood pressure was measured by tail cuff method. At the end of the experimental period myocardial interstitial fibrosis (Sirius Red staining) and myocardial hypertrophy were measured by histomorphometric analysis. Myocardial tyrosine hydroxylase expression, used as marker of sympathetic activity, was measured by immunohistochemistry. Results: Ang II caused a significant increase of blood pressure (p<0.0001), myocardial interstitial fibrosis (p<0.01), hypertrophy (p<0.01), and tyrosine hydroxylase expression (p<0.01) as compared to control groups. Empagliflozin treatment did not modify blood glucose in the different groups of rats. Empagliflozin administration did not modify the increase in blood pressure in Ang II treated rats, but prevented the development of myocardial fibrosis, hypertrophy, and tyrosine hydroxylase over-expression. Conclusions: These data demonstrate that in Ang II dependent hypertension Empagliflozin administration prevented the onset of myocardial fibrosis and hypertrophy through the reduction of local sympathetic activity. This effect is independent on the modulation of blood pressure and blood glucose levels.