Cyclosporine induces different responses in human epithelial, endothelial and fibroblast cell cultures

Background. Nephrotoxicity, accelerated atherosclerosis, and graft vascular disease are common complications of cyclosporine long-term treatment chara cterized by a wide disruption of organ architecture with increased intersti tial areas and accumulation of extracellular matrix (ECM). How cyclosporine induces these changes is not clear, but it is conceivable that they are th e sum of changes induced at the cell level. Methods. We studied the effects of cyclosporine on human endothelial (I-IEC ), epithelial (HK-2), and fibroblast (MRCS) cells. Cell proliferation was e valuated by cell counting, apoptosis and collagen production by enzyme-link ed immunosorbent assay, and nitric oxide by measuring the concentration of nitrite/nitrate in the cell supernatant. (alpha 1)I and (alpha 2)IV collage n, matrix metalloprotease-9 (MMP9), and tissue inhibitors of metalloproteas e-1 (TIMP-1) mRNA levels were measured by reverse transcription-polymerase chain reaction. Proteolytic activity was evaluated by zymography. Results. Cyclosporine showed a marked antiproliferative and proapoptotic ef fect on endothelial and epithelial cells. Fibroblast growth was not affecte d by cyclosporine. Nitric oxide was up-regulated by cyclosporine in epithel ial cells and fibroblasts but not in endothelial cells. (alpha 1)I and (alp ha 2)IV collagen synthesis was increased in cyclosporine-treated endothelia l and epithelial cells, respectively. Proteolytic activity was increased in endothelial and epithelial cells. TIMP-1 mRNA was upregulated by cyclospor ine in fibroblasts. Conclusions. Out results demonstrate that cyclosporine exhibits an antiprol iferative effect on endothelial and epithelial cells. This effect is associ ated with induction of apoptosis probably via nitric oxide up-regulation in epithelial cell cultures. Cyclosporine treatment induces ECM accumulation by increasing collagen synthesis in endothelial and epithelial cells and re ducing its degradation by up-regulating TIMP-1 expression in fibroblasts. W e conclude that cyclosporine affects cell types differently and that the di sruption of organ architecture is the result of multiple effects at the cel l level.