Levels of osteocalcin and procollagen I N-terminal propeptide (PINP) in men suffering from ankylosing spondylitis

Abstract

The aim: To evaluate osteocalcin and PINP levels in men suffering from AS and to compare them with structural and functional state of bone tissue and clinical course of illness. Materials and methods: The study included 82 patients suffering from AS with an average age of 40,9±0,9 years. Osteocalcin level was determined in 82 patients, and PINP level was determined in 79 patients. Control group included 22 apparently healthy persons. Disease activity was assessed through CRP level, ASDAS and BASDAI scores, while functional ability was assessed through the BASFI score. Osteocalcin and PINP levels were determined by immunoenzymatic method for the purpose of evaluating the metabolic state of bone tissue. Results: Average osteocalcin and PINP levels were not significantly different in patients suffering from AS and patients in the control group and did not show any significant correlation with ASDAS, BASDAI, BASFI and CRP scores. In patients with spinal ankylosis, average osteocalcin values (14,3 ng\ml) and PINP (747,2 pg\ml) were higher compared to patients with single syndesmophytes (11,0 ng\ml; 711,8 pg\ml) and patients without syndesmophytes (10,4 ng\ml; 537,7 pg\ml respectively). Conclusions: Osteocalcin and PINP levels are not related to age, disease duration, BMI, glucocorticoids load and inflammatory process activity, however, they are closely related to the presence of bone growths.