Reversible morphological and functional abnormalities of RINm5F cells cultured on polystyrene sulfonate beads

RINm5F cells (an insulin-secreting cell line) were cultured on PSSO3Na microbeads under static conditions. The cell growth rate was either identical to that of cells grown on plastic wells or slower, depending on the initial cell concentration. With both supports, it was similarly influenced by the fetal calf serum concentration in the culture medium, and protein content per cell was identical. However, no spreading was observed when cells were cultured on microbeads. RINm5F cells cultured on plastic wells responded to arginine + theophylline and to leucine + theophylline by a significant increase in insulin secretion. By contrast, in cells cultured on PSSO3Na microbeads, the increase in this secretion was only slight or nil. All these abnormalities were reversible. Thus, when cells cultured on microbeads were detached and seeded on plastic wells, normal spreading and insulin secretion were observed. Lastly, PSSO3Na beads had an acute suppressive effect on insulin secretion by cells cultured on plastic wells. This study provides an example of cell-biomaterial interaction in which cell growth is possible, but with altered cell function.