Role of platelet-derived growth factor in glomerular disease.

An approach for establishing a role for a growth factor in glomerular disease is presented. Using platelet-derived growth factor (PDGF) as an example, there is strong evidence to support the hypothesis that PDGF is a mediator of mesangial cell proliferation in glomerulonephritis. This includes evidence that (1) PDGF is a mitogen for mesangial cells in culture; (2) PDGF is expressed in both experimental and human glomerulonephritis in which mesangial cell proliferation occurs; (3) infusion of PDGF into rats induces mesangial cell proliferation and a hypercellular lesion; and (4) inhibition of PDGF in a model of experimental nephritis significantly reduces the mesangial cell proliferation. However, these data do not answer the question of whether or not the inhibition of PDGF in human diseases would be beneficial in the long term, because some cell proliferation is likely required for normal healing and repair. Further studies will be necessary to resolve this issue.