High-performance liquid chromatographic determination of pyridinium crosslinks in serum, urine and dialysate of patients in chronic renal failure.

This study describes an isocratic reversed phase high-performance liquid chromatographic method for the analysis of pyridinium crosslinks in serum, urine and dialysates obtained from patients with chronic renal failure on haemodialysis. The mean (SD) urine pyridinoline (PYD) and deoxypyridinoline (DPD) to creatinine (Cr) ratio in 19 healthy volunteers was 28.9 (6.3) and 9.1 (3.6) mumol/mol, respectively. In the 22 patients the PYD/Cr and DPD/Cr ratio was 244.6 (436.5) and 66.5 (116.8) mumol/mol, respectively. The mean serum PYD concentration in 29 patients of 268.5 (334.4) nmol/L was significantly higher than that of 5.9 (1.5) nmol/L found in normal volunteers: the mean DPD concentration was 82.9 (93.7) nmol/L in the patients but was undetectable in the serum from the normal volunteers. The concentration of crosslinks in pre-dialysis serum samples was higher than those found post-dialysis reflecting a significant removal of the crosslinks during dialysis. The assay of pyridinium crosslinks in serum, urine and dialyses fluid could potentially provide evidence of bone collagen turnover in patients in renal failure. Their measurement in serum and dialysate could be particularly useful in anuric patients.