Osteogenic Potency of Secretome Bone Marrow Derived Mesenchymal Stem Cells: A Literature Review

Treatment of non-union bone healing has been an unsolved problem in Orthopaedic surgery despite many advances. The most commonly adapted concept is the diamond concept including the osteoprogenitor cells, osteoinductive proteins, osteoconductive scaffolds and mechanical stability. Recent study groups worldwide have been studying the Mesenchymal Stem Cells as an adjunct to increase the bone healing process. However, newer literatures have shown that only few number of MSC transplanted will integrate. This paracrine mechanism is mediated by active secretion of cytokines, growth factors and enzymes called the secretome which is produced as a byproduct during the process of MSC culture. The addition of secretome itself alone is predicted to have the similar effect as the transplantation of MSC with less cost needed, and easier to obtain. The effect of MSC secretome has shown positive result on neurodegenerative disease, acute kidney disease, and cancer; but the effect on bone regeneration itself has never been studied. The MSC secretome have been proven to contain various cytokines (TGβ, some interleukins, GCSF, and many other cytokines) and growth factors (VEGF, EGF, PDGF, IGF-1, IGF-II, PLGF, HGF, NGF, BDNF). We also suspect the osteoinductive profile of MSC secretome due to the existence of BMP-2 which can be analysed using the ELISA spectrophotometry. The osteoinductive profile of secretome MSC will be able to replace the need of recombinant human BMP-2 (rhBMP-2) transplantation in treating bone defect and diminish the risk of excessive inflammation created by BMP-2 and also the carcinogenic potency.