Inflammation is intimately involved in the pathogenesis of diabetic kidney disease. Inhibition of SGLT-2 by a specific class of drugs, gliflozins, has been shown to reduce inflammation and attenuate the progression of diabetic nephropathy, in addition to its main effect of inhibiting renal glucose reabsorption. We used highly purified human renal proximal tubular epithelial cells (PTCs) as an in vitro model to study the cellular response to a diabetic (high glucose) and inflammatory (cytokines) microenvironment and the effect of gliflozins. In this context, we investigated the influence of SGLT-2 inhibition by empa- and dapagliflozin (500 nM) on the expression of pro-inflammatory factors (IL-1β, IL-6, TNF-α, MCP-1, and ICAM-1). The results clearly indicate an anti-inflammatory effect of both gliflozins. Although induced expression of the four cytokines was only slightly attenuated, there was a clear effect on the expression of the adhesion molecule ICAM-1, a master regulator of cellular responses in inflammation and injury resolution. The induced expression of ICAM-1 mRNA was significantly reduced by approximately 13.5% by empagliflozin and also showed an inhibitory trend with dapagliflozin. However, induced ICAM-1 protein expression was significantly inhibited from 24.71 ± 1.0 ng/mL to 18.81 ± 3.9 (empagliflozin) and 19.62 ± 2.1 ng/mL (dapagliflozin). In conclusion, an additional anti-inflammatory effect of empa- and dapagliflozin in therapeutically observed concentrations was demonstrated in primary human PTCs in vitro.
Keywords: ICAM-1; cytokines; dapagliflozin; empagliflozin; epithelial cells; inflammation; kidney; proximal tubule; renal tubular cells.