Effects of fondaparinux compared with dalteparin, enoxaparin and unfractionated heparin on human osteoblasts.

The objective of the this study was to examine the effects of fondaparinux, a synthetic anticoagulant substance similar to heparin, on osteoblasts compared with previously used heparins. Its effects have been shown in clinical trials to be highly effective in thromboembolism prophylaxis. Unfractionated heparin (UFH), dalteparin, enoxaparin and fondaparinux were added to osteoblast cultures in the therapeutic range and two decimal powers above and below it in each case. The results showed that the mitochondrial activity and protein synthesis of osteoblasts treated with fondaparinux were significantly higher than in the other groups. Similar effects could be demonstrated for the matrix collagen type II content and calcification. In contrast enoxaparin, dalteparin and UFH lead to a significant decrease of matrix collagen type II content and calcification in concentrations equal or higher than the therapeutic one. No inhibitory in-vitro effects of fondaparinux on human osteoblasts could be demonstrated within the concentration range investigated (0.01-100 microg/ml). We conclude that fondaparinux can be used to avoid the heparin-related negative influence on osteoblast-dependent fracture healing and endoprosthetic implant integration.