A new study on a potential Diabetes treatment entitled “Root of Polygonum cuspidatum extract reduces progression of diabetes-induced mesangial cell dysfunction via inhibition of platelet-derived growth factor-BB (PDGF-BB) and interaction with its receptor in streptozotocin-induced diabetic rats ” by Eunjin Sohn from the Korea Institute of Oriental Medicine (KIOM), explores the medicinal use of Polygonum cuspidatum for the disease.
In diabetes mellitus (DM), nephropathy is one of the main causes of death in the world. Platelet-derived growth factor (PDGF) has been implicated in the pathogenesis of several fibroproliferative diseases, like pulmonary fibrosis, systemic sclerosis, liver cirrhosis, cardiovascular disease and kidney fibrosis. An increased expression of the PDGF pathway has been demonstrated in the kidneys of diabetic animals and patients with diabetes mellitus. It seems that PDGF increases cell proliferation and matrix synthesis. PDGF-BB is an isoform of PDGF, which has been often associated with the development of several kidney diseases and is produced by glomerular mesangial cells. Notably, PDGF-BB is greatly expressed in diabetic renal tissues and has a crucial role in the initiation and progression of diabetic nephropathy.
In this study, the researchers investigated the protective effects of root of Polygonum cuspidatum extract (PCE) on early renal glomerular proliferation in rats where diabetes was induced by streptozotocin (STZ). Polygonum cuspidatum (P. cupidatum) is the dried root of Polygonum cuspidatum Sieb. et Zucc. (Polygonaceae). In Asia, it has been extensively used as a medicinal herb for different applications, such as therapy for inflammatory diseases, hepatitis, tumors, and diarrhea. In traditional Chinese medicine, P. cuspidatum has been utilized for its protective effects against diabetes and bacterial agents. It has been shown that an herbal medication with P. cuspidatum inhibited hepatic fibrosis through decreasing the expression of transforming growth factor-beta (TGF-ß) and α-smooth muscle actin (α-SMA) that have been implicated in the pathogenesis of renal fibrosis in diabetic patients with nephropathy.
The research team treated diabetic mice with PCE during 16 weeks. In the untreated diabetic mice it was observed severe hyperglycemia and albuminuria and a significantly augment of the expressions levels of α-SMA and PCNA proteins, PDGF-BB and its receptor in the glomeruli. Importantly, the treatment with PCE reduced markedly albuminuria as well as inhibited the increase of α-SMA and PCNA and improved PDGF-BB and PEGFR-ß protein expression in the diabetic rats. Using in vitro assay, it was observed that PCE inhibited the binding of PDGF-BB/PDGFR-ß.
In conclusion, this study shows that PCE seems to have an inhibitory effect on mesangial proliferation in diabetic renal tissues by inhibiting the binding of PDGF-BB with its receptor. These results suggest that PCE may have positive effects in preventing the course of diabetic nephropathy.