At present there is no known treatment for established glomerulosclerosis or atherosclerosis. Since the principal lesion in glomerulosclerosis involves mesangial cells, a vascular smooth muscle cell, we searched for new therapeutic approaches affecting vascular smooth muscle function, especially with respect to modifying the turnover of extracellular matrix. We used mice transgenic for bovine growth hormone (bGH), since these mice develop end-stage renal disease due to progressive glomerulosclerosis. We previously showed that the subcutaneous injection of a non-anticoagulant heparin reduced glomerulosclerosis in bGH mice. Since injectable drugs are not a practical means of controlling glomerulosclerosis in humans, we assessed oral heparin-like compounds and found that oral pentosan polysulfate (PPS) reduced glomerulosclerosis in bGH mice at non-toxic doses. Because the positive therapeutic response in the bGH model could have been principally hormone-mediated, we examined other models of non-immune mediated glomerulosclerosis, including ROP Os/+ non-diabetic and diabetic mice. We found that an oral PPS (Elmiron), which is approved for other indications in humans, reduced sclerosis in all of these forms of chronic, progressive glomerulosclerosis. Based on the similarity of the cellular events in glomerulosclerosis and arteriosclerosis, we assessed the effect(s) of PPS in congenital (Watanabe rabbits) and induced (New Zealand White lipid-fed rabbits) models of arteriosclerosis. The extent and severity of the lesions was significantly reduced in both models by PPS treatment. Finally, we asked whether the proliferative and sclerotic lesion, which is the cause of vascular graft stenosis, might also respond to PPS treatment. To do this we cultured cells from the materials removed from stenotic arteriovenous grafts in hemodialysis patients. We found that PPS inhibits the proliferation and matrix production in a dose-dependent manner.