SERUM CONCENTRATION OF THE AMINOPROPEPTIDE OF TYPE-I PROCOLLAGEN IN PATIENTS ON HEMODIALYSIS AND PERITONEAL-DIALYSIS

Using an ELISA technique, the aminopropeptide of type I procollagen (P INP) was measured in serum from patients with chronic renal failure tr eated with haemodialysis (HD) (n = 19) or continuous ambulatory perito neal dialysis (CAPD) (n = 14), and compared to the commonly used bone markers. The serum concentrations for PINP, compared to healthy contro ls 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 0.1 7 and 0.06 only. No significant difference was found between the HD an d CAPD patients with respect to serum levels of PINP, PTH, total alkal ine phosphatase, or ionized calcium. In the HD-patients, a significant ly higher level of serum phosphate was found compared to in the CAPD-p atients. The present study demonstrates a close correlation between PT H, total alkaline phosphatase and PINP, which indicates that PINP migh t be used as a marker for evaluating increased bone turnover in patien ts 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.