#851 Effects of gliflozins on endothelial cells: in vitro and clinical evidence

Abstract

Abstract Background and Aims Gliflozins are a class drugs widely used in diabetes as they act as sodium-glucose co-transporter type 2 inhibitors (SGLT2i). Irrespective from glycaemic control, SGLT2i are known to possess kidney and heart protective effects. The kidney- and heart-protective effects of gliflozins (SGLT2i) have received different explanations because of their efficacy in non-diabetic patients. Indeed, the non-glycemic effects of SGLT2i are puzzling because SGLT2, the molecular target of gliflozins, is mainly expressed in proximal tubule cells, with very low expression levels in other cell types. Though SGLT2 inhibitors might be nephroprotective because of a reduction of eGFR, this mechanism seems insufficient to explain heart protection. Emerging evidence suggests that SGLT2i have off-target effects in endothelial cells. In this study, we analyze this assumption by testing the effects of gliflozins on endothelial cells in vitro and verifying a differential effect of gliflozins on glomerular diseases involving primarily the endothelial compartment vs those involving podocytes or both. Methods In vitro studies have been conducted on EA.hy926 cells. A dose-response curve of gliflozins on mitochondrial activity and cell viability has been obtained using MTT staining. Morphological parameters were obtained using phase contrast microscopy, and the details of the plasma membranes were studied using Atomic Force microscopy. Patients with IgA nephropathy, minimal change disease or Focal Segmental Glomerulo Sclerosis FSGS, and with diabetic nephropathy (n = 12 per group). were studied for the percent change in albuminuria and creatinine four months after gliflozin treatment (empagliflozin or dapagliflozin). Three additional control groups (IgA, podocytopathies, diabetes) without gliflozin treatment (n = 12 per group) were also included. Results Gliflozin treatment induced a dose-response improvement in EA.hy926 cells' survival and restoration of cell-cell borders in AFM images. In patients, the albuminuria was reduced by a similar extent (−38 ± 6%) in all groups when treated with gliflozins. However, in diabetic patients and podocytopathies, this was associated with decreased eGFR (−6% and −8%), whereas in IgA nephropathy, the eGFR levels were increased after treatment (+3.8%). Conclusion In vitro, gliflozins show a direct endothelial protection effect. In vivo, part of the effects on proteinuria may be explained by a hemodynamic effect on the glomerular filtration rate in diseases affecting podocytes (diabetes, MCD, FSGS), as shown by the increase in creatinine. However, for diseases involving the endothelium (IgA nephropathy), the endothelial protection effect of gliflozins is demonstrated by the reduction in proteinuria and the protective effect on creatinine levels.