Rice bran protein hydrolysates attenuate diabetic nephropathy in diabetic animal model.

INTRODUCTION: Diabetic nephropathy (DN) is an important microvascular complication of uncontrolled diabetes. The features of DN include albuminuria, extracellular matrix alterations, and progressive renal insufficiency. Rice bran protein hydrolysates (RBPs) have been reported to have antihyperglycemic, lipid-lowering, and anti-inflammatory effects in diabetic rats. Our study was to investigate the renoprotective effects of RBP in diabetic animals and mesangial cultured cells. METHODS: Eight-week-old male db/m and db/db mice were orally treated with tap water or RBP (100 or 500 mg/kg/day) for 8 weeks. At the end of the experiment, diabetic nephropathy in kidney tissues was investigated for histological, ultrastructural, and clinical chemistry changes, and biomarkers of angiogenesis, fibrosis, inflammation, and antioxidant in kidney were analyzed by Western blotting. Protection against proangiogenic proteins and induction of cytoprotection by RBP in cultured mesangial cells was evaluated. RESULTS: RBP treatment improved insulin sensitivity, decreased elevated fasting serum glucose levels, and improved serum lipid levels and urinary albumin/creatinine ratios in diabetic mice. RBP ameliorated the decreases in podocyte slit pore numbers, thickening of glomerular basement membranes, and mesangial matrix expansion and suppressed elevation of MCP-1, ICAM-1, HIF-1α, VEGF, TGF-ß, p-Smad2/3, and type IV collagen expression. Moreover, RBP restored suppressed antioxidant Nrf2 and HO-1 expression. In cultured mesangial cells, RBP inhibited high glucose-induced angiogenic protein expression and induced the expression of Nrf2 and HO-1. CONCLUSION: RBP attenuates the progression of diabetic nephropathy and restored renal function by suppressing the expression of proangiogenic and profibrotic proteins, inhibiting proinflammatory mediators, and restoring the antioxidant and cytoprotective system.

Prospective study of serum uric acid levels and incident metabolic syndrome in a Korean rural cohort.

OBJECTIVE: Recent studies have demonstrated an association between serum uric acid (SUA) levels and metabolic syndrome (MetS). However, paucity of available data regarding the cause and effect relationship between SUA and MetS in healthy adults is still a big challenge which remains to be studied. Therefore, we investigated whether SUA predicts new onset of MetS in a population-based cohort study. METHODS: The study included 1590 adults (661 men and 929 women) aged 40-70 years without MetS at baseline (2005-2008) and subjects were prospectively followed for 2.6 years. To evaluate the relationship between SUA and MetS, we divided the aforementioned subjects into quintiles (SUA-I to SUA-V) from the lowest to the highest values of SUA. SUA was measured by the enzymatic colorimetric method. We used category-free net reclassification improvement (NRI) and integrated discrimination improvement (IDI) to characterize the performance of predicted model. RESULTS: During a mean of 2.6 years of follow-up, 261(16.4%) adults developed MetS. MetS variables were significantly related to the baseline SUA level. Waist circumference (WC), blood pressure (BP), and serum triglyceride (TG) were significantly higher in the highest quintile of SUA compared to the lowest SUA quintile in men and women. After adjustment for age, total cholesterol and low-density lipoprotein cholesterol (LDL-C) in men and women, subjects in the fifth quintiles of SUA showed significantly higher ORs for incident MetS. The association between hyperuricemia and new onset of MetS were consistently stronger in women than men. Additionally, among women, we found an improvement in the area under the ROC curve in the models that added SUA to core components of MetS. CONCLUSION: Our study suggests that SUA is significantly correlated with future risk of WC, BP, TG and may predicted as a risk factor for developing MetS. SUA may have a clinical role in predicting new-onset metabolic syndrome among women. Large prospective study is needed to reveal the clinical significance of SUA in metabolic disease.