Early administration of empagliflozin preserved heart function in cardiorenal syndrome in rat

Abstract

This study tested the hypothesis that early administration of empagliflozin (Empa), an inhibitor of glucose recycling in renal tubules, could preserve heart function in cardiorenal syndrome (CRS) in rat. Chronic kidney disease (CKD) was caused by 5/6 subtotal nephrectomy and dilated cardiomyopathy (DCM) by doxorubicin (DOX) treatment. In vitro results showed that protein expressions of cleaved-caspase3 and autophagy activity at 24 h/48 h in NRK-52P cells were significantly upregulated by para-Creso treatment; these were significantly downregulated by Empa treatment. Flow cytometric analysis showed that annexin-V (i.e., early/late apoptosis) in NRK-52P cells expressed an identical pattern to cleaved-caspase3 between the two groups (all p < 0.001). Adult-male-SD rats (n = 18) were equally categorized into group 1 (sham-control), group 2 (CRS) and group 3 [CRS + Empa; 20 mg/kg/day]. By day-42 after CRS induction, left-ventricular ejection fraction (LVEF) level exhibited an opposite pattern, whereas LV end-diastolic dimension and creatinine level displayed the same pattern, to cleaved-caspase3 among the three groups (all p < 0.0001). In LV tissues, protein expressions of inflammatory (tumor-necrosis factor-α/nuclear-factor-κB/interleukin-1ß/matrix-metalloprotianse-9), oxidative stress (NOX-1/NOX-2/oxidized protein), apoptotic (mitochondrial-Bax/cleaved-caspase-3/cleaved-PARP), fibrotic (transforming-growth factor-ß/Smad3), DNA/mitochondrial-damage (γ-H2AX/cytosolic-cytochrome-C) and heart failure (brain natriuretic peptide (BNP) levels displayed an opposite pattern to LVEF among the three groups (all p < 0.0001). Additionally, cellular expressions of DNA-damage/heart-failure (γ-H2AX+//XRCC1+CD90+//BNP+) biomarkers and histopathological findings of fibrotic/condensed collagen-deposition areas and apoptotic nuclei showed an identical pattern, whereas connexin43 and small-vessel number exhibited an opposite pattern, to inflammation among the three groups (all p < 0.0001). In conclusion, Empa therapy protected heart and kidney against CRS injury.

Keywords: Cardiorenal syndrome; Empagliflozin; Heart function; Inflammation; Oxidative stress.