Coacervate whey protein improves inflammatory milieu in mice fed with high-fat diet

Inhibition of 11β-HSD1 by LG13 improves glucose metabolism in type 2 diabetic mice

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) controls the production of active glucocorticoid (GC) and has been proposed as a new target for the treatment of type 2 diabetes. We have previously reported that a natural product, curcumin, exhibited moderate inhibition and selectivity on 11β-HSD1. By analyzing the models of protein, microsome, cells and GCs-induced mice in vitro and in vivo, this study presented a novel curcumin analog, LG13, as a potent selective 11β-HSD1 inhibitor. In vivo, Type 2 diabetic mice were treated with LG13 for 42 days to assess the pharmacological benefits of 11β-HSD1 inhibitor on hepatic glucose metabolism. In vitro studies revealed that LG13 selectively inhibited 11β-HSD1 with IC50 values at nanomolar level and high selectivity over 11β-HSD2. Targeting 11β-HSD1, LG13 could inhibit prednisone-induced adverse changes in mice, but had no effects on dexamethasone-induced ones. Further, the 11β-HSD1 inhibitors also suppressed 11β-HSD1 and GR expression, indicating a possible positive feedback system in the 11β-HSD1/GR cycle. In type 2 diabetic mice induced by high fat diet plus low-dosage STZ injection, oral administration with LG13 for 6 weeks significantly decreased fasting blood glucose, hepatic glucose metabolism, structural disorders, and lipid deposits. LG13 exhibited better pharmacological effects in vivo than insulin sensitizer pioglitazone and potential 11β-HSD1 inhibitor PF-915275. These pharmacological and mechanistic insights on LG13 also provide us novel agents, leading structures, and strategy for the development of 11β-HSD1 inhibitors treating metabolic syndromes.

Dietary Whey and Casein Differentially Affect Energy Balance, Gut Hormones, Glucose Metabolism, and Taste Preference in Diet-Induced Obese Rats

BACKGROUND

Dietary whey and casein proteins decrease food intake and body weight and improve glycemic control; however, little is known about the underlying mechanisms.

OBJECTIVE

We determined the effects of dietary whey, casein, and a combination of the 2 on energy balance, hormones, glucose metabolism, and taste preference in rats.

METHODS

In Expt. 1, Obesity Prone CD (OP-CD) rats were fed a high-fat control diet (33% fat energy) for 8 wk, and then randomly assigned to 4 isocaloric dietary treatments (n = 12/group): the control treatment (CO; 14% protein energy from egg white), the whey treatment (WH; 26% whey + 14% egg white), the casein treatment (CA; 26% casein + 14% egg white), or the whey plus casein treatment (WHCA; 13% whey + 13% casein + 14% egg white) for 28 d. Measurements included food intake, energy expenditure, body composition, metabolic hormones, glucose tolerance and key tissue markers of glucose and energy metabolism. In Expt. 2, naïve OP-CD rats were randomly assigned to 3 groups (n = 8/group). During an 8 d conditioning period, each group received on alternate days either the CO or WH, CO or CA, or CO or WHCA. Subsequently, preferences for the test diets were assessed on 2 consecutive days with food intake measurements at regular intervals.

RESULTS

In Expt. 1, food intake was decreased by 17-37% for the first 14 d in the WH and CA rats, and by 18-34% only for the first 4 d in the WHCA compared with the CO rats. Fat mass decreased by 21-28% for the WH rats and 17-33% for the CA rats from day 14 onward, but by 30% only on day 28 in WHCA rats, relative to CO rats. Thus, food intake, body weight, and fat mass decreased more rapidly in WH and CA rats than in WHCA rats. Energy expenditure in WH rats decreased for the first 4 d compared with CA and WHCA rats, and for the first 7 d compared with the CO rats. Circulating leptin, glucose-dependent insulinotropic polypeptide, interleukin 6, and glucose concentrations were lower in WH, CA, and WHCA rats than in CO rats. Plasma glucagon-like peptide 1 concentrations were greater in WH than in CA or WHCA rats. The improvements in glucose tolerance were greater in WH than in WHCA rats. The plasma membrane glucose transporter 4 (GLUT4)-to-total GLUT4 ratio in skeletal muscle was greater in CA and WHCA rats than in CO rats; other markers of glucose and energy metabolism in the adipose and cardiac tissues did not differ. In Expt. 2, during 4 conditioning trials, daily food intake was decreased in WH, CA, and WHCA rats by 26-37%, 30-43%, and 23-33%, respectively, compared with CO rats. Preferences for WH and CA rats were 45% and 31% lower, respectively, than those for CO rats, but that for WHCA rats did not differ.

CONCLUSION

Together, these data demonstrate that in obese rats, whey, casein, and their combination improve energy balance through differential effects on food intake, taste preference, energy expenditure, glucose tolerance, and gut hormone secretion.

Preventive effects of chitosan coacervate whey protein on body composition and immunometabolic aspect in obese mice

Functional foods containing bioactive compounds of whey may play an important role in prevention and treatment of obesity. The aim of this study was to investigate the prospects of the biotechnological process of coacervation of whey proteins (CWP) in chitosan and test its antiobesogenic potential. Methods. CWP (100 mg·kg·day) was administered in mice with diet-induced obesity for 8 weeks. The animals were divided into four groups: control normocaloric diet gavage with water (C) or coacervate (C-CWP), and high fat diet gavage with water (HF) or coacervate (HF-CWP). Results. HF-CWP reduced weight gain and serum lipid fractions and displayed reduced adiposity and insulin. Adiponectin was significantly higher in HF-CWP group when compared to the HF. The level of LPS in HF-W group was significantly higher when compared to HF-CWP. The IL-10 showed an inverse correlation between the levels of insulin and glucose in the mesenteric adipose tissue in the HF-CWP group. CWP promoted an increase in both phosphorylation AMPK and the amount of ATGL in the mesenteric adipose tissue in HF-CWP group. Conclusion. CWP was able to modulate effects, possibly due to its high biological value of proteins. We observed a protective effect against obesity and improved the inflammatory milieu of white adipose tissue.