[Measurement and clinical significance of serum concentrations of pyridinium cross-links in patients with renal osteodystrophy].

Serum concentration of the pyridinium cross-links, pyridinoline (Pyr) and deoxypyridinoline (Dpyr), which are markers of bone resorption, was measured by high-performance liquid chromatography in 56 patients on maintenance hemodialysis. The following analyses were conducted: 1) correlation with known markers of bone metabolism, 2) correlation with findings on bone changes on plain X-ray film, 3) elimination rates by hemodialysis, and 4) increment per day in pyridinoline after hemodialysis (delta Pyr/day). There was a very close correlation found between serum Pyr and Dpyr (r = 0.861). Both serum Pyr and Dpyr showed correlations with known markers of bone metabolism: C-PTH (r = 0.806 and r = 0.747, respectively), M-PTH (r = 0.766 and r = 0.749), osteocalcin (r = 0.717 and r = 0.693), Alp-3 (r = 0.523 and r = 0.441) and tartrateresistant acid phosphatase (r = 0.549 and r = 0.548). In addition, a correlation between the duration of hemodialysis and serum Pyr and Dpyr was observed (r = 0.426 and r = 0.318, respectively). When comparing the mean values of serum Pyr or Dpyr in three groups of patients divided according to bone changes seen on plain X-ray film, there were statistically significant differences between the group without bone changes and the remaining two groups with some bone changes (p < 0.05). A mean of 45.3% of serum Pyr was removed by hemodialysis. The serum Pyr level returned almost to the original concentration by the following hemodialysis. delta Pyr/day showed a close correlation with C-PTH (r = 0.656).(ABSTRACT TRUNCATED AT 250 WORDS)