The possibility of three types of cells in cultured glomeruli in vitro.

Although three types of cells are known to exist in glomeruli in vivo, it is not clear whether the same is true of glomerular cells in vitro. The outgrowth from the cultured glomeruli was continuously monitored with time-lapse cinemicroscopy until the glomerular tissues completely disappeared. The results clearly indicated that only two types of cells arise from the glomeruli in vitro, epithelial (E cell) and fibroblastic (M cell). A cell line of M cells was established that showed relatively constant morphologic characteristics as compared with the M cells in primary cultures. Morphologic evidence was obtained indicating that M cells produce GBM-like materials and collagen fibers with clearly visible periodicity.