ANALYSIS AND OSTEOGENIC POTENTIAL OF HUMAN SERUM ISOLATED AFTER FRACTURE

Abstract

The purpose of this study was to assess the effect of human autologous serum on the proliferation and differentiation of MSCs and to analyze the serum growth factor content. Serum was obtained from 8 patients suffering from lower limb long bone fractures requiring surgical intervention.

Serum samples were obtained on admission and the 1st-3rd–5th and 7th postoperative day. During the surgical procedure cancellous bone pieces from the fracture were obtained and MSCs were isolated. Cells were cultured with autologous serum from each sample. The cellular potential for proliferation and osteogenic differentiation was assessed. Fetal calf serum (FCS) was used for comparison. The presence of growth factors in the serum was investigated using commercially available colorimetric assays read on Elisa plate reader. We studied the serum content on Platelet Derived Growth Factor (PDGF), Vascular Endothelial Growth Factor (VEGF) and Insulin-like Growth Factor I (IGF-1).

The maximal upregulation of cellular proliferation and osteogenic differentiation was noted in cells cultured from serum obtained between third and seventh days. Cellular proliferation in comparison to FCS was increased by 32% with the use of serum from admission, 23% with the use of serum of the 1st day and 37% and 42% with the serum from 3rd and 7th days respectively. Serum analysis revealed an increase of 80% of PDGF between the 1st and 3rd postoperative day and 135% from 3rd–7th postoperative day. IGF-1 was increased by 35% between day 1 and 7. VEGF was increased by 120% during the first two postoperative days and a further increase of 190% occurred between days 3 and 7.

Growth factors are released in peripheral circulation and are gradually increased after fracture. MSCs under their influence proliferate faster and up-modulate their osteogenic differentiation. These findings should be considered when using functional assays for tissue regeneration techniques.