Calcium citrate improves the epithelial-to-mesenchymal transition induced by acidosis in proximal tubular cells

introduction: epithelial-to-mesenchymal transition (emt) is a key event in renal fibrosis. the aims of the study were to evaluate acidosis induced emt, transforming-growth-factor (tgf) β1 role and citrate effect on it. methods: hk2 cells (atcc 2290) were cultured in dmem/ham f12 medium, ph 7.4. at 80% confluence, after 24 hr under serum free conditions, cells were distributed in three groups (24 hours): a) control: ph 7.4, b) acidosis: ph 7.0 and c) calcium citrate (0.2 mmol/l) + ph 7.0. change (δ) of intracellular calcium concentration, basal and after angiotensin ii (10-6m) exposition, were measured to evaluate cellular performance. emt was evaluated by the expression of α-smooth muscle actin (α-sma) and e-cadherin by immunocytochemistry and/or western blot. tgf-β1 secretion was determined by elisa in cell supernatant. results: at ph 7.0 hk2 cells significantly reduced e-cadherin and increased α-sma expression (emt). supernatant tgf-β1 levels were higher than in control group. calcium citrate decreased acidosis induced emt and improved cells performance, without reduction of tgf-β production. conclusions: acidosis induces emt and secretion of tgf-β1 in tubular proximal cells in culture and citrate improves cellular performance and ameliorates acidosis induced emt.