Factors modifying collagen catabolism in patients with ankylosing spondylitis.

OBJECTIVE: We quantified the total excretion of the collagen crosslinks (CL) pyridinoline (PYD) and deoxypyridinoline (DPD) in 108 ankylosing spondylitis (AS) patients (29 f, 79 m) in correlation to different characteristics of disease to evaluate different mechanism contributing to development of osteoporosis in AS. METHODS: PYD and DPD were measured by HPLC. RESULTS: AS patients show a highly significant positive correlation between PYD and inflammatory activity. In cases involving peripheral joints, significantly higher CL levels in urine were found. Patients with syndesmophytes excreted significantly more CL vs. those without. In the more advanced stages of sacroiliitis (stage III and IV), CL levels tended to be higher. Among those patients treated with NSAIDs, a tendency to decreased levels of DPD and consecutive raised levels of the quotient PYD/DPD were observed. No significant correlation was found between restricted spine mobility or duration of disease and amount of excreted CL. CONCLUSIONS: Our investigations show that the inflammatory process, the involvement of the peripheral joints, the presence of syndesmophytes and the stage of sacroiliitis all have an influence on the extent of collagen degradation in AS patients. NSAIDs do not increase but appear to reduce collagen I catabolism.

[Collagen breakdown in ankylosing spondylitis-relationship to disease related parameters]. / Kollagenabbauaktivität bei Spondylitis ankylosans in Beziehung zu krankheitsrelevanten Daten.

OBJECTIVE: Patients with ankylosing spondylitis (AS) often develop osteoporosis particularly of the axis skeleton. To investigate disease-related or therapeutic influence on bone catabolism, we quantified the total excretion of the collagen crosslinks (CL) pyridinoline (Pyd) and deoxypyridinoline (Dpyd) in 91 AS patients (26 f, 65 m) in relation to disease activity or stage and therapy with NSAID. METHODS: CL were determined by HPLC (High Performance Liquid Chromatography). RESULTS: The AS patients show a highly significant positive correlation between Pyd and the inflammatory activity (CrP, r = 0.36, p < 0.001: ESR, r = 0.379, p < 0.001). Also the quotient Pyd/Dpyd correlates positively to the inflammatory activity (CrP, r = 0.262, p < 0.001: ESR, r = 0.325, p < 0.002). In the case of increased inflammatory disease activity (CrP > or = 10 mg/l vs CrP < 10 mg/l or ESR > or = 10 30 mm vs ESR < 30 mm), Pyd excretion is raised significantly (p < 0.042 for CrP and p < 0.009 for ESR). Among those patients treated with NSAID therapy, significantly reduced levels for Dpyd (p < 0.001) and raised levels for the quotient Pyd/Dpyd (p < 0.002) appear. In the case of advanced radiological changes with evidence of syndesmophytes, Pyd (p = 0.014) and Dpyd (p < 0.004) were significantly raised in urine. Regarding the movement function (finger-floor distance, schober test), no significant correlation to crosslink excretion could be proven. CONCLUSION: From our investigations, we assume that osteoporosis in AS is primarily caused by an inflammatory-mediated degradation of bone.