Increased urinary pyridinoline cross-link compounds of collagen in patients with systemic sclerosis and Raynaud's phenomenon

Objective. To study concentration changes in collagen degradation markers i npatients with diffuse and limited cutaneous systemic sclerosis and patient s with scleroderma-related diseases. Methods. Pyridinoline cross-link compounds were analysed in urine samples u sing high-performance liquid chromatography. Samples were analysed for pyri dinoline (Pyr), deoxypyridinoline (Dpyr) and soft-tissue pyridinoline (stPy r) in patients with diffuse cutaneous systemic sclerosis (dcSSc, n = 23) an d limited cutaneous systemic sclerosis (IcSSc, n = 48) and in patients with scleroderma-related diseases such as primary Raynaud's phenomenon (pRP, n = 16) and secondary Raynaud's phenomenon (sRP, n = 14). Healthy controls (n = 18) and patients with post-menopausal osteoporosis (OP, n = 35) were als o investigated. Results. Urinary Pyr, Dpyr and stPyr concentrations were significantly high er in patients with Raynaud's phenomenon and systemic sclerosis than in hea lthy controls. The highest concentrations (two to three times greater than in healthy controls) were found in patients with dcSSc. The stPyr concentra tion was significantly higher in patients with dcSSc than in those with IcS Sc, sRP and pRP. No significant difference in stPyr concentration was found between the healthy controls and the OP group, suggesting that stPyr is de rived from soft tissues rather than bone. The extent and severity of skin i nvolvement, measured as a skin score, significantly correlated with the con centrations of stPyr and Pyr, whereas no such correlation was found for Dpy r. Conclusions. Increased urinary concentrations of piridinoline cross-links r eflect alterations in collagen turnover in both Raynaud's phenomenon and sy stemic sclerosis. The close correlation between stPyr concentration and the extent of skin involvement in systemic sclerosis suggests that this parame ter may be useful in monitoring ongoing fibrosis in this disease.