(421a) Culture of Human Cells in Asymmetric Laminar Flow Systems

In biomedical and tissue engineering applications, such as the expansion of progenitor or endothelial cells, static culture in Petri dishes and bottles is the most common culture strategy. In this contribution, we examine the effect of asymmetric laminar flows of the rate of growth and protein secretion/expression of human stem cells and endothelial cells cultured on Petri dishes. Asymmetric flows within dishes were induced by placing them at different eccentric positions (6.5 and 9,5 cm form the rotational center) in a rotational platform (rotated at 3, 5 and 8 RPM). We observed significant and reproducible growth acceleration of CD34+ umbilical cord derived Human Hematopoietic Progenitor Cells when exposed to rotational flow as compared to stationary conditions. Growth dynamics under 3 or 5 RPM agitation was compared against that observed under typical stationary conditions. Cells cultured at 3 or 5 RPM exhibited (a) the absence of a latency phase, (b) an increase in final cell concentrations by 54%-58.5%, and (c) reduced doubling time in their exponential phase by 12-16% in comparison to stationary culture. Cells grown under rotational agitation were confirmed to remain CD34+ by PCR. These results document a significant positive effect of exposure to laminar flow fields on the growth of human hematopoietic progenitor cells. In experiments with endothelial cells significant differences in both, secretion level and glycosylation patterns (extend and completeness of glycosylation) were observed as a result of relatively small changes in rotational speed. These results support the hypothesis that differences in hydrodynamic conditions may induce important changes in the secretion and assembly of glycoproteins in mammalian cell cultures.