Behavioral Changes of Multipotent Mesenchymal Stromal Cells in Contact with Synthetic Calcium Phosphates in vitro

Abstract

Migration, proliferation, and osteogenic differentiation of human adipose-derived (AD) multipotent mesenchymal stromal cells (MMSCs) during in vitro modeling of indirect contact with calcium phosphate (CP) or nanoparticles of synthetic hydroxyapatite (HA) have been studied. The results were registered with electrode (real-time cell analysis, RTCA) or visual (Cell-IQ) systems of long-term observation of cell cultures. Bulk specimens were use in a Cell-IQ® v2 MLF device as pure titanium substrates (10 × 10 × 1 mm3) covered by a CP relief (roughness index Ra = 2.4–4.4 μm) bilateral coating that was prepared by the micr-arc method from an aqueous solution of orthophosphoric acid (20 wt %), calcium carbonate (9 wt %), and synthetic HA (6 wt %). HA crystallites (1 mg/mL) were fabricated by mechanochemical synthesis and served as an irritant in RTCA investigation. The Cell-IQ system identified a 3.5- to 10-fold decrease in cell number at the interface with CP coatings with differing roughness during 14-day cell culturing. After 21 days, it was accompanied by a weak reduction of MMSC antigen expression (CD73, CD90, and CD105) as opposed to an increase in MMSC osteogenic differentiation and intercellular-matrix mineralization. In turn, HA nanodispersion reduced the speed of MMSC migration by 1.5 times (P < 0.001) during 25-h RTCA recording, which simulated cell invasion through the microporous membrane (8-μm diameter). Inhibition of migration and cell division with increased osteogenic differentiation of MMSCs has been suggested to be a possible effect of biodegradation products of synthetic CP materials.