Study of the Role of Heparin in Regulation of the Morphofunctional Properties of MSC <i>in Vitro</i>

Abstract

Introduction. Artificial materials used in regenerative medicine induce a balanced inflammatory response after implantation, which is an important step for effective regeneration of damaged bone tissue. The contact of the implant with tissues and biological fluids is accompanied by the deposition of blood proteins on its surface, which contributes to the activation of the complement system and initiates blood clotting, leading to the formation of a fibrin clot. On the surface of the implant, fibrin ensures the adhesion of stem cells and their maturation into fibroblasts that produce collagen and its derivatives. The formed extracellular matrix is the basis for the formation of a tissue structure (callus). To prevent the development of postoperative pathological conditions caused by hypercoagulatory syndrome, therapeutic strategies with anticoagulants such as heparin are used. However, their use limits the formation of a fibrin clot in vivo, which may slow down the migration of mesenchymal stromal cells (MSCs) and the subsequent formation of callus. Aim. To investigate of the effect of heparin at pharmacological concentrations on stemness and the ability of MSCs from human adipose tissue to undergo osteogenic differentiation under conditions of in vitro cultivation. Materials and methods. To assess the morphofunctional state of cells cultured in the presence of heparin, 2 experimental groups were formed: 1) MSCs in the presence of heparin at a therapeutic concentration (1.3 IU/ml); 2) MSCs in the presence of heparin at a toxic concentration (13 IU/ml). Results and discussion. Flow cytometry results showed that the addition of heparin at both concentrations used in the study to MSC culture leads to an increase in the number of cells expressing the surface markers CD73 and CD90, indicating the maintenance of their stem state. On the other hand, a stimulatory effect of heparin at both concentrations used on the transcription of mRNA of osteogenic genes (BMP2, BMP6, ALPL, RUNX2, BGLAP and SMURF1) in MSCs was also observed, which may indicate the osteogenic potential of heparin for the cell culture studied. Conclusion. The results of the study are useful for regenerative medicine related to the use of MSCs in clinical practice; they may serve as a prerequisite for the development of new therapeutic strategies for orthopedic and traumatologic patients at high risk of postoperative thrombosis after endoprosthetics surgery and osteosynthesis.