Background: Vascular calcification (VC) progresses substantially even in the case of stable kidney transplantation, and is a predictor of morbidity and mortality. However, the effect of cyclosporin A (CsA) on VC has not been reported in diabetic kidney transplant patients. In this study, we evaluated the effect of CsA on the VC of mouse vascular smooth muscle cells (VSMCs), in the diabetic milieu.
Methods: CsA of a concentration of 1.0 µmol/L was selected by the MTT assay for this study. To demonstrate the effect of CsA and high glucose (HG, 30mM) in the induction of the VC of the VSMCs, we determined alkaline phosphatase (ALP) activity, microscopic morphology of calcification, the expressions of the calcification and inflammation-related genes, and the intracellular calcium concentrations in VSMCs.
Results: Calcification was observed 14 days after exposure to a calcifying medium (sodium phosphate monobasic and dibasic mixture). On microscopic morphology, CsA alone did not induce calcification under HG conditions, but clearly increased calcification under HG with a calcifying medium. ALP activity increased under HG with CsA or a calcifying medium compared to HG conditions alone. CsA increased ALP activity under low glucose (LG, 5.5mM) with a calcifying medium, but markedly increased under HG with a calcifying medium. CsA significantly increased the mRNA expressions of the calcification markers (core binding factor-alpha 1, bone morphologic proteins 2) as well as those of the inflammatory marker (interleukin 6), under HG with a calcifying medium. Intracellular calcium concentrations was unchanged in CsA alone but significantly increased with the presence of a calcifying medium under both LG and HG conditions,
Conclusion: Considering the effect of CsA on VC, the vascular side effects of CsA need to be verified in diabetic transplant patients, in the future.