title: Relationship between disease activity and serum levels of vitamin D metabolites and parathyroid hormone in ankylosing spondylitis.
abstract: Vertebral fractures due to osteoporosis are a common but frequently unrecognized complication of ankylosing spondylitis (AS) and various factors may contribute to the development of osteoporosis in AS. It is known that inflammatory activity in rheumatic disease (i.e., proinflammatory cytokines) itself plays a possible role in the pathophysiology of bone loss. 1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) seems to be another possible candidate for mediatory function in regulating both the inflammatory process and bone turnover. The aim of this study was to evaluate the relation between disease activity, bone turnover and calciotropic hormones. In 70 patients with established AS and an age- and sex-matched control group, the relation between disease activity (erythrocyte sedimentation rate, C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index), and serum levels of vitamin D metabolites, parathyroid hormone (PTH), bone alkaline phosphatase (bAP) and urinary pyridinium cross-links were determined. Serum levels of 1,25(OH)2D3 (p<0.01) and PTH (p<0.01) were negatively correlated with disease activity, the excretion of urinary pyridinium crosslinks showed a positive correlation with disease activity (p<0.01), and 1,25(OH)2D3 and PTH were positively correlated with bAP (p<0.01). These results indicate that high disease activity in AS is associated with an alteration in vitamin D metabolism and increased bone resorption. Furthermore, the decreased levels of 1,25(OH)2D3 may contribute to a negative calcium balance and inhibition of bone formation. Our results suggest further research is necessary to determine whether low levels of 1,25(OH)2D3 as an endogenous immune modulator suppressing activated T cells and cell proliferation may accelerate the inflammation process in AS.
authors.affiliation: Kerckhoff Clinic and Foundation, Department of Rheumatology, University of Giessen, Bad Nauheim, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Lange
authors.forename: O
authors.initials: O
authors.lastname: Jung
authors.forename: J
authors.initials: J
authors.lastname: Teichmann
authors.forename: G
authors.initials: G
authors.lastname: Neeck
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D016723:Bone Remodeling; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000209:etiology; D010281:Parathyroid Hormone / Q000097:blood*; D011726:Pyridinium Compounds / Q000652:urine; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D013250:Steroid Hydroxylases / Q000097:blood*; D014807:Vitamin D / Q000378:metabolism
chemical_list: D010281:Parathyroid Hormone; D011726:Pyridinium Compounds; D014807:Vitamin D; D013250:Steroid Hydroxylases; C406322:vitamin D 1-alpha hydroxylase; D000469:Alkaline Phosphatase