Empagliflozin ameliorates endothelial dysfunction and suppresses atherogenesis in diabetic apolipoprotein E-deficient...

Recent studies reported cardioprotective effects of sodium glucose co-transporter 2 (SGLT2) inhibitors; however, the underlying mechanisms are still obscure. Here, we investigated whether empagliflozin attenuates atherogenesis and endothelial dysfunction in diabetic apolipoprotein E-deficient (ApoE^-/-) mice. Male streptozotocin (STZ) - induced diabetic ApoE^-/- mice were treated with empagliflozin for 12 or 8 weeks. Empagliflozin lowered blood glucose (P < 0.001) and lipid levels in diabetic ApoE^-/- mice. Empagliflozin treatment for 12 weeks significantly decreased atherosclerotic lesion size in the aortic arch (P < 0.01) along with reduction of lipid deposition (P < 0.05), macrophage accumulation (P < 0.001), and inflammatory molecule expression in plaques compared with the untreated group. Empagliflozin treatment for 8 weeks significantly ameliorated diabetes-induced endothelial dysfunction as determined by the vascular response to acetylcholine (P < 0.001). Empagliflozin reduced RNA expression of a macrophage marker, CD68, and inflammatory molecules such as MCP-1 (P < 0.05) and NADPH oxidase subunits in the aorta compared with the untreated group. Empagliflozin also reduced plasma levels of vasoconstrictive eicosanoids, prostaglandin E₂ and thromboxane B₂ (P < 0.001), which were elevated in diabetic condition. Furthermore, empagliflozin attenuated RNA expression of inflammatory molecules in perivascular adipose tissue (PVAT), suggesting the reduction of inflammation in PVAT. In in vitro studies, methylglyoxal (MGO), a precursor of AGEs, significantly increased the expression of inflammatory molecules such as MCP-1 and TNF-α in a murine macrophage cell line, RAW264.7. Our results indicated that empagliflozin attenuated endothelial dysfunction and atherogenesis in diabetic ApoE^-/- mice. Reduction of vasoconstrictive eicosanoids and inflammation in the vasculature and PVAT may have a role as underlying mechanisms at least partially.