Background: It has been previously shown that in elderly patients with osteoporosis the Mesenchymal Stem Cell (MSC) growth rate and osteogenic potential is decreased. The aim of this study was to elucidate the effect of BMP-2, BMP-7, PTH and PDGF on MSC’s capacity to proliferate and differentiate.

Methods: Cancellous bone samples were obtained from 10 patients (mean age 76 (70–84), (4 males)) suffering from lower extremity fractures and osteoporosis. Mes-enchymal Stem Cells (MSCs) were isolated by enzymatic digestion. Cells were cultured till passage 3 (P3). Functional assays on proliferation and osteogenic differentiation were performed under the influence of a wide range of BMP-2, BMP-7, PTH and PDGF concentrations. Proliferation was assessed using CFU-F and XTT assays. Osteogenic differentiation was assessed by alkaline phosphatase activity and total calcium production.

Results: MSC proliferation was found upregulated by medium supplementation with BMP-7 and PDGF. The highest proliferation rate increase was achieved with 100 ng/ml of BMP-7. BMP-2 and PTH did not affect MSC proliferation. All four molecules upregulated ALP activity and calcium production by growing osteoblasts. A dose dependant effect was noted. BMP-2 and BMP-7 in their highest studied concentration (100 ng/ml) produced a ~ three-fold increase on osteogenic potential of MSCs.

Conclusion: This study indicates that BMP-7 and BMP-2 have favourable effect on osteogenic differentiation of MSCs. However, BMP-7 could be more advantageous as it enhances both proliferation and osteogenic differentiation of MSCs derived from elderly osteoporotic bone.

Purpose: Growth factors are released and circulate in peripheral blood after fracture. The purpose of this study was to characterize the early systemic release of several growth factors following accidental fractures and surgery.

Methods: 14 patients (8 male and 6 female) suffering from lower limb long bone fractures were prospectively included in the study. The mean age was 34 years (range 18-61). In all patients the time from fracture occurrence till operation was less than 24 hours. Peripheral blood samples were collected on patients’ admission, induction, and postoperatively at 1, 3 and 5 days. Serum was extracted and using Elisa colorimetric assays the concentration of Platelet Derived Growth Factor (PDGF), Vascular Endothelial Growth Factor (VEGF), Insulin-like Growth Factor I (IGF-1) and Transforming Growth Factor beta 1 (TGF-b1) was measured.

Results: From fracture occurrence till induction for surgery a substantial decreased was observed (VEGF concentration was decreased by 189%, PDGF was decreased by 363%, TGF-b1 was decreased by 247 % and IGF-1 was decreased only by 25%. Surgery itself decreased VEGF peripheral levels by a further 50% and PDGF by 40 % while IGF and TGF-b1 levels remained unchanged. During the first post-operative day the levels of VEGF were increased by 82%, TGF-b1 and IGF-1 remained constant and PDGF was further decreased by 20%. Between the 1st and 3rd postoperative days VEGF was increased by 132%, PDGF by 220% and TGF-b1 by 230 %. During this period, IGF-1 was decreased by 20 %. Finally, during the 3rd to 5th postoperative day, the levels of all growth factors continue to increase.

Conclusion: This study illustrates the early pattern of release of 4 growth factors following fractures and surgery. A substantial decreased during the first 24 hours was noted but thereafter an upward trend was observed. This data provide insight into the levels and kinetics of growth factors before and after surgery of fractures.