STIMULATING EFFECT OF HIGH DOSE HEPARIN ON MIGRATION ACTIVITY AND MSC STEMNESS PRESERVATION IN THE PRESENCE OF BONE-SUBSTITUTING MATERIALS

Abstract

Synthetic materials used in regenerative medicine, upon implantation, induce the development of an inflammatory reaction necessary for the effective regeneration of damaged bone tissue. Implant contact with tissues is accompanied by the deposition of blood proteins and interstitial fluid on its surface, contributing to the activation of the complement system, components of innate immunity, initiating coagulation hemostasis, leading to the formation of a fibrin clot. An extracellular matrix based on fibrin, collagen and elastin forms on the implant’s surface, which provides the basis for the formation of tissue structure through the adhesion of stem cells to the forming bone callus before the formation of bone regenerate. To prevent the development of postoperative pathological conditions caused by hypercoagulable syndrome, therapeutic strategies are used to use anticoagulants (heparin, warfarin). However, their use limits the normal formation of a fibrin clot in vivo. This can slow down the migration of mesenchymal stem cells (MSC) and disrupt the formation of callus, inhibiting the processes of osseointegration of the implant and bone healing. The study’s goal was to study the effect of heparin in a gradient of low and high concentrations on the migration activity and stem capacity of human MSCs underin vitrocultivation conditions. According to the results of flow cytometry, it was revealed that high concentrations of heparin (130, 260 IU/ml) in a 2D cultivation model contribute to an increase in the number of cells expressing surface markers CD73 and CD90, which indicates that MSCs retain high clonogenic potential. A 3D model ofin vitrocultivation with the addition of heparin and osteosubstituting implants bearing a CF coating with a roughness index of Ra = 2.6-4.9 μm contributed to preserving the “stemness” character of MSCs through the expression of surface markers CD73 and CD90. According to the results obtained using the xCELLigence system, heparin at a later time (from 20-40 hours) increases the invasion of MSCs through micropores that simulate the state of the blood vessel walls. However, in the presence of HAP nanoparticles that mimic the remodeling processes of the mineral bone matrix and/or resorption of bone cement, the effect of heparin was less pronounced. The results can be used in the field of regenerative medicine associated with the introduction of MSCs. The data can serve as a prerequisite for developing new therapeutic strategies for surgical patients with a high risk of postoperative thrombosis after osteosynthesis.