Abnormal vascular endothelial growth factor expression in mesenchymal stem cells from both osteonecrotic and osteoarthritic hips

In osteonecrosis (ON) of the hip, interruption of angiogenesis is a pathological process that may lead to impairment of the nutrient supply, cell death, and the collapse of bone. However, the process of angiogenesis in ON is not well understood. The purpose of this study was to investigate the expression of vascular endothelial growth factor (VEGF) in human mesenchymal stem cells (MSCs) in vitro. Cultured MSCs obtained from the hips of normal, ON, and osteoarthritic (OA) patients all expressed VEGF-A. Furthermore, MSCs from normal stem cells also expressed VEGF-B, but its expression had a tendency to increase in those stem cells from ON and OA patients, while VEGF-C was absent in all of the stem cells. However, VEGF-D expression consistently decreased in MSCs from ON patients, but increased in stem cells from OA donors over that of control cells. In addition, placental growth factor (PGF), which has a similar function as VEGF, was expressed in MSCs, and the levels were similar in MSCs from normal, ON, and OA donors. The results suggest that ON and OA are associated with aberrant VEGF-D expression.