Interaction between MSCS and blood mononuclear cells during <i>in vitro</i> co-cultivation in the presence of a three-dimensional artificial matrix mimicking regenerating bone tissue

Bone tissue repair and regeneration is a complex process involving many cells and controlled by multiple factors. Immune cells and cytokines play a crucial role in regulating the balance of bone formation and resorption. However, the immunomodulatory mechanism of bone regeneration is still unclear. Nevertheless, the reciprocal regulatory influence of immunocompetent cells and mesenchymal stem cells (MSCs) is well known. MSCs and immunocompetent cells secrete various cytokines, growth factors, and extracellular matrix molecules that play important roles in regulating hematopoiesis, angiogenesis, immune and inflammatory responses. Several studies confirm that different molecules expressed by MSCs may induce lymphocyte proliferation. Therefore, the study of the mutual influence of MSCs and blood mononuclear cells during in vitro co-cultivation, even in the presence of an artificial matrix mimicking regenerating bone tissue, is relevant and expedient. In this experimental series, the studies were performed at the interface between living and non-living substrate phases thus mimicking the regenerating bone / hematopoietic microenvironment system. A series of separated in time experiments was performed on a plastic surface (2D culture model) and in the presence of three-dimensional artificial matrices mimicking regenerating bone tissue (3D culture model).