Bone Abstracts

The aim of the study is to determine whether there is an imbalance between bone formation and bone resorption in nonbacterial osteitis. The osteoclast inhibitor pamidronate has been successfully used in nonbacterial osteitis. It is assumed, that there is any mismatch in the pathophysiology of osteoblasts or osteoclasts. Until now, we have no known publications on bone metabolism in nonbacterial osteitis. We chose osteoprotegerin (OP) and alkaline phosphatase (AP) as markers of bone formation and dickkopf-1 (DKK-1) and cathepsin k as markers of bone resorption.

The serum levels of osteoprotegerin, alkaline phosphatase, dickkopf-1 and cathepsin k were measured in 55 patients, in 7–25 years of age, using enzyme link immunoassay test. We compared the serum levels of OP, DKK-1 with an average value of a healthy control group from the literature.

74% of patients had low levels of OP in comparison to normative data. All patients had lower levels of DKK-1. A significant difference in levels of DKK-1 was observed between patients who didn’t receive pamidronate or etanercept during the observation period and patients who needed these drugs in the course of disease (P=0.023). No significant difference was found by OP (P=0.592). AP was in the normal range. Serum level of cathepsin k was just detecting in one patient.

They weren’t significant results by OP and DKK-1 in follow groups: unifocal vs multifocal bone lesions (OP P=0.05, DKK-1 P=0.861), with vs without hyperostosis (OP P=0.863, DKK-1 P=0.544), high vs no high serum levels of TNF-α (OP P=0.768, DKK-1 P=0.547), axial vs no axial involvement (OP P=0.993, DKK-1 P=0.186), vertebral body involvement vs no vertebral body involvement (OP P=0.241, DKK-1 P=0.505).

Patients with nonbacterial osteitis had a low turnover in bone remodeling. Patients with a serious course of disease may have more osteoclast activity than other patients in terms of DKK-1 levels.

Disclosure: The study was partially financed by Novartis.