Serum concentration of the aminopropeptide of type I procollagen in patients on haemo- and peritoneal dialysis.

ABSTRACT

Using an ELISA technique, the aminopropeptide of type I procollagen (PINP) was measured in serum from patients with chronic renal failure treated with haemodialysis (HD) (n = 19) or continuous ambulatory peritoneal dialysis (CAPD) (n = 14), and compared to the commonly used bone markers. The serum concentrations for PINP, compared to healthy controls were significantly increased in both the HD-group (p < 0.00001) and the CAPD-group (p < 0.00001). In the HD-group a close correlation was found between PINP and parathyroid hormone (PTH) (R(s) = 0.745; p = 0.00026) and between PINP and total alkaline phosphatase (R(s) = 0.623; p = 0.004), but in the CAPD-group the corresponding p-values were 0.17 and 0.06 only. No significant difference was found between the HD and CAPD patients with respect to serum levels of PINP, PTH, total alkaline phosphatase, or ionized calcium. In the HD-patients, a significantly higher level of serum phosphate was found compared to in the CAPD-patients. The present study demonstrates a close correlation between PTH, total alkaline phosphatase and PINP, which indicates that PINP might be used as a marker for evaluating increased bone turnover in patients with chronic renal failure treated with haemodialysis, and perhaps also in patients treated with peritoneal dialysis, and that the ideal biochemical parameters to analyse changes in bone metabolism in these patients may be a combination of the initiating hormone (PTH) and PINP as a marker of the effect of PTH on bone metabolism.