Reduced shear stress: a major component in the ability of mammalian tissues to form three-dimensional assemblies in simulated microgravity.

BHK-21 cells were cultured under various shear stress conditions in an Integrated Rotating-Wall Vessel (IRWV). Shear ranged from 0.5 dyn/cm2 (simulated microgravity) to 0.92 dyn/cm2. Under simulated microgravity conditions, BHK-21 cells complexed into three-dimensional cellular aggregates attaining 6 x 10(6) cells/ml as compared to growth under 0.92 dyn/cm2 conditions. Glucose utilization in simulated microgravity was reduced significantly, and cellular damage at the microcarrier surface was kept to a minimum. Thus, the integrated rotating wall vessel provides a quiescent environment for the culture of mammalian cells.