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.

Dietary fish protein hydrolysates containing bioactive motifs affect serum and adipose tissue fatty acid compositions, serum lipids, postprandial glucose regulation and growth in obese Zucker fa/fa rats.

The world's fisheries and aquaculture industries produce vast amounts of protein-containing by-products that can be enzymatically hydrolysed to smaller peptides and possibly be used as additives to functional foods and nutraceuticals targeted for patients with obesity-related metabolic disorders. To investigate the effects of fish protein hydrolysates on markers of metabolic disorders, obese Zucker fa/fa rats consumed diets with 75 % of protein from casein/whey (CAS) and 25 % from herring (HER) or salmon (SAL) protein hydrolysate from rest raw material, or 100 % protein from CAS for 4 weeks. The fatty acid compositions were similar in the experimental diets, and none of them contained any long-chain n-3 PUFA. Ratios of lysine:arginine and methionine:glycine were lower in HER and SAL diets when compared with CAS, and taurine was detected only in fish protein hydrolysate diets. Motifs with reported hypocholesterolemic or antidiabetic activities were identified in both fish protein hydrolysates. Rats fed HER diet had lower serum HDL-cholesterol and LDL-cholesterol, and higher serum TAG, MUFA and n-3:n-6 PUFA ratio compared with CAS-fed rats. SAL rats gained more weight and had better postprandial glucose regulation compared with CAS rats. Serum lipids and fatty acids were only marginally affected by SAL, but adipose tissue contained less total SFA and more total n-3 PUFA when compared with CAS. To conclude, diets containing hydrolysed rest raw material from herring or salmon proteins may affect growth, lipid metabolism, postprandial glucose regulation and fatty acid composition in serum and adipose tissue in obese Zucker rats.

Improvement of glycemic control in streptozotocin-induced diabetic rats by Atlantic salmon skin gelatin hydrolysate as the dipeptidyl-peptidase IV inhibitor.

In our previous study, Atlantic salmon skin gelatin hydrolysed with flavourzyme possessed 42.5% dipeptidyl-peptidase (DPP)-IV inhibitory activity at a concentration of 5 mg mL(-1). The oral administration of the hydrolysate (FSGH) at a single dose of 300 mg per day in streptozotocin (STZ)-induced diabetic rats for 5 weeks was evaluated for its antidiabetic effect. During the 5-week experiment, body weight increased, and the food and water intake was reduced by FSGH in diabetic rats. The daily administration of FSGH for 5 weeks was effective for lowering the blood glucose levels of diabetic rats during an oral glucose tolerance test (OGTT). After the 5-week treatment, plasma DPP-IV activity was inhibited; the plasma activity of glucagon-like peptide-1 (GLP-1), insulin, and the insulin-to-glucagon ratio were increased by FSGH in diabetic rats. The results indicate that FSGH has the function of inhibiting GLP-1 degradation by DPP-IV, resulting in the enhancement of insulin secretion and improvement of glycemic control in STZ-induced diabetic rats.

Effects of hydrolysed casein, intact casein and intact whey protein on energy expenditure and appetite regulation: a randomised, controlled, cross-over study.

Casein and whey differ in amino acid composition and in the rate of absorption; however, the absorption rate of casein can be increased to mimic that of whey by exogenous hydrolysis. The objective of the present study was to compare the effects of hydrolysed casein (HC), intact casein (IC) and intact whey (IW) on energy expenditure (EE) and appetite regulation, and thereby to investigate the influence of amino acid composition and the rate of absorption. In the present randomised cross-over study, twenty-four overweight and moderately obese young men and women consumed three isoenergetic dietary treatments that varied in protein source. The study was conducted in a respiration chamber, where EE, substrate oxidation and subjective appetite were measured over 24 h at three independent visits. Moreover, blood and urine samples were collected from the participants. The results showed no differences in 24 h and postprandial EE or appetite regulation. However, lipid oxidation, estimated from the respiratory quotient (RQ), was found to be higher after consumption of IW than after consumption of HC during daytime (P= 0·014) as well as during the time after the breakfast meal (P= 0·008) when the food was provided. Likewise, NEFA concentrations were found to be higher after consumption of IW than after consumption of HC and IC (P< 0·01). However, there was no overall difference in the concentration of insulin or glucagon-like peptide 1. In conclusion, dietary treatments when served as high-protein mixed meals induced similar effects on EE and appetite regulation, except for lipid oxidation, where RQ values suggest that it is higher after consumption of IW than after consumption of HC.

Is prevention of atopic eczema with hydrolyzed formulas cost-effective? A health economic evaluation from Germany.

OBJECTIVE: The German Infant Nutritional Intervention (GINI) trial, a prospective, randomized, double-blind intervention, enrolled children with a hereditary risk for atopy. When fed with certain hydrolyzed formulas for the first 4 months of life, the risk was reduced by 26-45% in PP and 8-29% in intention-to-treat (ITT) analyses compared with children fed with regular cow's milk at age 6. The objective was to assess the cost-effectiveness of feeding hydrolyzed formulas. PATIENTS AND METHODS: Cost-effectiveness was assessed with a decision tree model programmed in TreeAge. Costs and effects over a 6-yr period were analyzed from the perspective of the German statutory health insurance (SHI) and a societal perspective at a 3% effective discount rate followed by sensitivity analyses. RESULTS: The extensively hydrolyzed casein formula would be the most cost-saving strategy with savings of 478 € per child treated in the ITT analysis (CI95%: 12 €; 852 €) and 979 € in the PP analysis (95%CI: 355 €; 1455 €) from a societal perspective. If prevented cases are considered, the partially whey hydrolyzed formula is cost-saving (ITT -5404 €, PP -6358 €). From an SHI perspective, the partially whey hydrolyzed formula is cost-effective, but may also be cost-saving depending on the scenario. An extensively hydrolyzed whey formula also included into the analysis was dominated in all analyses. CONCLUSIONS: For the prevention of AE, two formulas can be cost-effective or even cost-saving. We recommend that SHI should reimburse formula feeding or at least the difference between costs for cow's milk formula and the most cost-effective formula.

Upgrading of sea by-products: potential nutraceutical applications.

Since many years, numerous kinds of processes based on enzymatic hydrolysis at various pH, involving added plant or bacterial enzymes after inactivation by heating of endogenous enzymes present in the raw material or, alternatively, based on the action of endogenous enzymes, have contributed to the degradation of marine by-product proteins in order to produce fractions exerting biological activities. Peptides obtained by enzymatic hydrolysis of fish proteins exhibit not only nutritional but also biological properties of dietary uses, or even therapeutic potential. In this review, we have focused on the different enzymatic processes able to generate bioactive peptides from marine by-products and exerting high potential in nutraceutical applications to fight against important public health issues like obesity, stress, hypertension, and migraine. Beyond the nutraceutical and pharmaceutical aspects, this way of valorization is also included in the necessary development of by-product fishing industries for economic and ecological reasons in the worldwide context of marine resources depletion.