M. Takahashi et al., Comparison of free and peptide-bound pyridinoline cross-links excretion inrheumatoid arthritis and osteoarthritis, RHEUMATOLOG, 38(2), 1999, pp. 133-138
Objective. To investigate urinary fractions of free and peptide forms of py
ridinoline crosslinks in arthritis.
Patients and methods. The free and total forms of pyridinoline (Pyr) and de
oxypyridinoline (Dpyr) were measured by high-performance liquid chromatogra
phy (HPLC) in 30 premenopausal and 22 post-menopausal normal women, 38 wome
n with rheumatoid arthritis (RA) and 62 women with osteoarthritis (OA). Pep
tide forms were calculated as total minus free. Free Dpyr and peptide form
were also measured by deoxypyridinoline and carboxyterminal telopeptide of
type I collagen (CTx) immunoassays.
Results. In normal women, all fractions of Pyr and Dpyr and immunoassays we
re elevated in post-menopause compared to pre-menopause. In post-menopausal
normal women, the free form increased more than the peptide form. In RA, a
n increase in the fractions of Pyr was greater than Dpyr. Peptide and total
cross-links correlated with the disease activity of RA and they were eleva
ted in RA patients with high disease activity. Free Dpyr and CTx were signi
ficantly lower in OA than in normal women. Peptide and total Pyr and Dpyr,
and immunoassayed Dpyr were significantly higher in the radiographic later
stage of OA than in the early stage of OA.
Conclusions. The menopause, RA and OA may have different effects on the uri
nary excretion of free and peptide-bound pyridinoline cross-links.