Pilot in vitro study of the parameters of artificial niche for osteogenic differentiation of human stromal stem cell pool

The aim of this research is experimental investigation of the topography and evaluation of some parameters of artificial microterritories promoting osteogenic differentiation of stromal stem cells. A technique of short-term culturing of prenatal human lung stromal cells with fibroblastoid morphology on calcium phosphate substrates with known topography was used. Judging from secretory activity of the cell culture (osteocalcin, alkaline phosphatase), stromal stem cells directly interacting with calcium phosphate discs have advantage in manifestation of osteoblast-like functional activity in comparison with cells cultured on plastic. Rough surfaces of calcium phosphate discs stimulate the formation of spatial human fibroblastoid cell culture. The cells with positive reaction to acid phosphatase are located on spheroliths forming the relief of calcium phosphate coatings. The cells with positive reaction to alkaline phosphatase (marker of osteoblasts) populate hollows (niches) of the artificial surface. The niche for induction of osteogenic differentiation of human multipotent mesenchymal stem cells is apparently a structural and functional formation. It can be characterized by an index calculated as the ratio of the total area occupied by alkaline phosphatase-positive cells to the area of artificial surface occupied by one stained cell.