Evolution of circulating C-terminal propeptide of type I procollagen in patients with chronic renal failure pre and post renal transplantation.

The carboxyterminal propeptide of type I procollagen is a biochemical marker of type I collagen synthesis. We evaluated circulating carboxyterminal propetide of type I procollagen levels in patients with terminal renal failure before and after kidney transplantation. Serum carboxyterminal propeptide of type I procollagen, osteocalcin, total alkaline phosphatase, intact parathyrin, creatinine, calcium and phosphate levels were determined in 20 patients, before and 15, 30, 90 and 180 days after surgery. Serum creatinine and intact parathyrin concentrations showed a significant decrease after kidney transplantation. Immunosuppressive treatment consisted of low dose prednisone, cyclosporin and antilymphoblast globulin. In our group, only 5 patients (25%) showed serum carboxyterminal propeptide of type I procollagen levels higher than normal before kidney transplantation. At 15 and 30 days, carboxyterminal propeptide of type I procollagen concentrations showed a decrease, while at 90 and 180 days there was a significant increase above the normal range (p = 0.006; ANOVA). Serum osteocalcin and total alkaline phosphatase levels increased significantly at the same time. We found a significant correlation between carboxyterminal propetide of type I procollagen and osteocalcin at 15 and 30 days after kidney transplantation. We conclude that the significant increase in carboxyterminal propeptide of type I procollagen levels after kidney transplantation reflect an increase in bone turnover. The low doses of steroids employed do not seem to have a significant inhibitory effect on collagen synthesis.