Collagen Cross-Linking Telopeptide in Osteonecrosis of the Jaws

Osteonecrosis of the jaws (ONJ) can be an adverse effect of bisphosphonates, particularly those used intravenously. This creates a dilemma in planning surgery, and raises the need for prognostic markers to predict its likely development. Collagen type I serum C-terminal cross-linking telopeptide (CTX) can determine bone turnover and act as a marker of resorption in some disorders.

Objectives: We aimed to test the hypothesis that CTX is a biological marker in ONJ (Marx RE et al. J Oral Maxillofac Surg. 2007; 65:2397-2410).

Methods: We retrospectively studied 15 patients with ONJ (group 1) comparing with 10 healthy controls matched by age and gender (group 2), a study approved by the Ethical Committee of the University General Hospital, Valencia. All patients had cancers (7 breast; 6 myeloma; the others lung or prostate) and were treated with an intravenous high potency bisphosphonate zoledronic acid (5 also were treated with pamidronate).Degradation products of C-terminal telopeptides of type I collagen were quantified in serum, using enzyme-linked immunosorbent assay (Serum CrossLaps ELISA, Nordic Bioscience, Denmark).

Results: The mean serum CTX level in group 1 (ONJ) was 294.10 pg/ml ± 76.27 (mean ± standard error) and was significantly higher (Mann-Whitney test U=30, p=0.01) at 490.56 pg/ml ± 77.71 (mean ± SE) in group 2 (controls). There were no statistically significant relationships in group 1 between serum CTX and either the number of areas of bone exposed (Spearman test =0.006 p >0.05) or with the size of the osteonecrotic areas (Spearman test =0.010 p >0.05).

Conclusions: Serum CTX level are decreased in patients with ONJ, which might be of prognostic value, but this needs confirming prospectively and in other regimens.