Total and free deoxypyridinoline after acute osteoclast activity inhibition

Alessandro Rubinacci, Raffaella Melzi, Maria Zampino, Armando Soldarini, Isabella Villa

Research output: Contribution to journalArticle

Abstract

Background: Deoxypyridinoline (Dpd) is one of the two pyridinium cross- links that provide structural rigidity to type I collagen in bone. During osteoclastic resorption, Dpd is released into circulation and is excreted in the urine in free and peptide-bound forms. Free and total Dpd are highly correlated, but whether the free-to-total cross-link ratio is constant in both normal and high bone turnover states remains controversial. To compare free and total Dpd performance in a physiological condition, urinary free and total Dpd were measured after a short-term inhibition of osteoclast activity such as that induced by an oral calcium load. Methods: Total and free Dpd were measured by HPLC and by immunosorbent assay, respectively, in two groups of subjects, one (calcium-treated; n = 16) taking calcium and the other not (control; n = 9). Results: The urinary excretion of total Dpd at 2 and 4 h after oral calcium loading was decreased compared with controls. By contrast, changes in free Dpd were similar in the calcium-treated and control groups, reflecting only circadian rhythm. Conclusions: Total and free Dpd do not show comparable sensitivity in detecting short-term inhibition of osteoclast activity. The degradation process of peptide-bound to free Dpd could render free Dpd insensitive to acute changes of osteoclast activity.

Original languageEnglish
Pages (from-to)1510-1516
Number of pages7
JournalClinical Chemistry
Volume45
Issue number9
Publication statusPublished - 1999

ASJC Scopus subject areas

  • Clinical Biochemistry

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