Kantonsspital St.Gallen

Endostatin inhibits Callus remodeling during fracture healing in mice

Joerg H Holstein, Bianca Karabin-Kehl, Claudia Scheuer, Patric Garcia, Tina Histing, Christoph Meier, Emanuel Benninger, Michael D Menger & Tim Pohlemann

abstract Information on the impact of endogenous anti-angiogenic factors on bone repair is limited. The hypothesis of the present study was endostatin, an endogenous inhibitor of angiogenesis, disturbs fracture healing. We evaluated this hypothesis in a closed femoral fracture model studying two groups of mice, one that was treated by a daily injection of 10 µg recombinant endostatin subcutaneously (n = 38) and a second one that received the vehicle for control (n = 37). Histomorphometric analysis showed a significantly increased callus formation in endostatin-treated animals at 2 and 5 weeks post-fracture. This was associated with a significantly higher callus tissue fraction of cartilage and fibrous tissue at 2 weeks and a significantly higher fraction of bone at 5 weeks post-fracture. Biomechanical testing revealed a significantly higher torsional stiffness in the endostatin group at 2 weeks. For both groups, we could demonstrate the expression of the endostatin receptor unit integrin alpha5 in endothelial cells, osteoblasts, osteoclasts, and chondrocytes at 2 weeks. Immunohistochemical fluorescence staining of CD31 showed a lower number of blood vessels in endostatin-treated animals compared to controls. The results of the present study indicate endostatin promotes soft callus formation but inhibits callus remodeling during fracture healing most probably by an inhibition of angiogenesis.
citation Holstein J H, Karabin-Kehl B, Scheuer C, Garcia P, Histing T, Meier C, Benninger E, Menger M D, Pohlemann T. Endostatin inhibits Callus remodeling during fracture healing in mice. J Orthop Res 2013; 31:1579-84.
type journal paper/review (English)
date of publishing 30-05-2013
journal title J Orthop Res (31/10)
ISSN electronic 1554-527X
pages 1579-84
PubMed 23720153
DOI 10.1002/jor.22401