Human glomerular cells in vitro: isolation and characterization.

Human glomerular cells were isolated, identified, and propagated in vitro, and a number of features were found to be unique to glomerular visceral epithelial and mesangial cells. Epithelial cells are identified by their "epithelial" morphology in vitro, growth pattern, presence of C3b surface receptors, response to mitogens, synthesis of a single collagen type (IV), and nearly exclusive synthesis of one type of sulfated glycosaminoglycan, heparan sulfate. Mesangial cells differ from epithelial cells and other potential contaminating cells, such as fibroblasts or endothelial cells, by their characteristic light and electron microscopic morphology and their synthesis of specific collagen and glycosaminoglycan types. In addition, while they closely resemble vascular smooth muscle cells in many ways, they differ with respect to their response to mitogens. It should now be possible to study these cells for other features, including the presence of alloantigens. This property and their response to inflammatory mediators or cells are prerequisites to the determination of their role in the pathogenesis of renal allograft rejection.