[Immunoregulatory role of mesenchymal stem cells in bone reparation processes].

Bone marrow contains mesenchymal stem cells (MSC) including osteoblast progenitor cells. When culturedunder conditions promoting an osteoblastic phenotype,MSC proliferate to form colonies that produce alkaline phosphatase and, subsequently, a mature osteoblastic phenotype. Transplantation of cultured autologous MSC to patients with non-healing bone fractures gives a good result leading to complete bone fracture consolidation. The aim of the study is to determine a quantitative production of IL-1beta, IL-2, IL-4, IL-6, IL-8 and TNF-alpha by cultured uncommitted and committed osteogenic MSC. The results showed that the cytokine profile consisting of IL-1beta, IL-2, IL-4, IL-6, IL-8 and TNF-alpha is secreted by cultured MSC. The secretion of IL-1beta and IL-2 by cultured MSC together with hyper production of IL-6 (up to 276.5 pg/ml, p<0.05) and IL-8 (up to 106.6 ng/ml, p<0.05) by osteoinducted MSC are firstly shown. The immunoregulatory role of transplanted autologous cells in inflammation and own bone reparation processes during posttraumatic bone fracture healing is highlighted. In conclusion, the data obtained allow examining of cultured autologous MSC as effective activators of bone resorption, inflammation and some immunological reactions in the process of altered osteoreparation.