Increased serum bone sialoprotein concentrations in patients with Crohn's disease

Impaired calcium homeostasis and/or the administration of corticosteroids are considered to be among the factors contributing to the pathogenesis of osteopenia in patients with inflammatory bowel disease. There is an increasing evidence suggesting that certain pro-inflammatory cytokines may also directly influence the bone metabolism in these patients. Routine measurement of bone mass and loss usually include dual energy X-ray absorptiometry as well as urinary and serum assessment of collagen crosslinks. More recent studies include likewise the detection of bone sialoprotein into a specific diagnostics of bone turnover.

We investigated 47 patients with inflammatory bowel disease (Crohn's disease N = 41, ulcerative colitis N = 6) and 17 healthy volunteers to assess and compare serum levels of bone sialoprotein and other routine parameters of bone turnover. Bone sialoprotein levels were measured by using a recently described radioimmunoassay.

In comparison to the control group, bone sialoprotein and urinary crosslinks were significantly increased only in patients with Crohn's disease, while other markers of bone turnover (e. g. alkaline phosphatase, carboxylterminal propeptide of typ I procollagen, urinary deoxypyridinoline, vitamin D, phosphate and calcium) did not differ significantly between the patients' groups.

According to these data, increased serum bone sialoprotein concentrations seem to be an additional valuable and sensitive marker of bone resorption in patients with Crohn's disease.