Oxintomodulina e obesidade

Design and characterization of novel oxyntomodulin derivatives with potent dual GLP-1/glucagon receptor activation and prolonged antidiabetic effects

AIMS

To investigate the combination of dimerization and PEGylation to enhance the receptor activation and in vivo stability of Oxyntomodulin (OXM).

MAIN METHODS

All LDM peptides were produced by using standard method of solid phase synthesis. The in vitro effects of LDM peptides were assessed by glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GcgR) binding test and Proteolytic stability test. Subsequently, saline, Liraglutide and three doses of LDM-3 treated groups were subjected to the evaluation of aute and long-term efficacy.

KEY FINDINGS

Five long-acting OXM conjugates, termed LDM-1 to LDM-5, were designed using cysteine (Cys)-specific modification reaction including the activated PEG, bisMal-NH₂, and OXM-Cys, and all prepared with high purity. LDM-3 exhibited greater GLP-1R and GcgR activation and ameliorative serum stability. In addition, LDM-3 was identified with enhanced insulinotropic and glycemic abilities in the gene knockout mice. The prolonged glucose-lowering effects of the LDM-3 were proved by hypoglycemic duration test and multiple oral glucose tolerance tests (OGTTs) in the diet-induced obesity (DIO) mice. Furthermore, the pharmacokinetic tests in Sprague Dawley (SD) rat and cynomolgus monkey exhibited the lifespans of LDM-3 at 90 nmol·kg^-1 were 101.5 h and 119.4 h, respectively. Nevertheless, consecutive 8-week administration of LDM-3 improved the cumulative body weight gain, food intake, % HbA1c, glucose tolerance and the pancreatic of the obese mice.

SIGNIFICANCE

LDM-3, as a dual GLP-1R and GcgR agonist, holds potential to be developed as a promising therapeutic candidate for both diabetes and obesity.

Dietary whey protein lessens several risk factors for metabolic diseases: a review

Obesity and type 2 diabetes mellitus (DM) have grown in prevalence around the world, and recently, related diseases have been considered epidemic. Given the high cost of treatment of obesity/DM-associated diseases, strategies such as dietary manipulation have been widely studied; among them, the whey protein diet has reached popularity because it has been suggested as a strategy for the prevention and treatment of obesity and DM in both humans and animals. Among its main actions, the following activities stand out: reduction of serum glucose in healthy individuals, impaired glucose tolerance in DM and obese patients; reduction in body weight; maintenance of muscle mass; increases in the release of anorectic hormones such as cholecystokinin, leptin, and glucagon like-peptide 1 (GLP-1); and a decrease in the orexigenic hormone ghrelin. Furthermore, studies have shown that whey protein can also lead to reductions in blood pressure, inflammation, and oxidative stress.

Gut-central nervous system axis is a target for nutritional therapies

Historically, in the 1950s, the chemist Linus Pauling established a relationship between decreased longevity and obesity. At this time, with the advent of studies involving the mechanisms that modulate appetite control, some researchers observed that the hypothalamus is the "appetite centre" and that peripheral tissues have important roles in the modulation of gut inflammatory processes and levels of hormones that control food intake. Likewise, the advances of physiological and molecular mechanisms for patients with obesity, type 2 diabetes mellitus, inflammatory bowel diseases, bariatric surgery and anorexia-associated diseases has been greatly appreciated by nutritionists. Therefore, this review highlights the relationship between the gut-central nervous system axis and targets for nutritional therapies.

Appetite-related hormone levels in obese women with and without binge eating behavior

OBJECTIVE: The aim of this study was to evaluate serum levels of appetite-related hormones (peptide YY3-36, total ghrelin, leptin and insulin) before and after consumption of a meal in obese women with and without binge eating episodes and normal weight women. METHODS: Twenty-five women aged 32-50 years were invited to participate in this study, including 9 normal weight women without binge eating episodes (20-25kg/m², group 1), 9 obese women with binge eating episodes (³30kg/m², group 2), and 7 obese women without binge eating episodes (group 3). Four blood samples were collected from each participant, one being 60 minutes before and three being 15, 45 and 90 minutes after a meal. The composition of the meal was 55% carbohydrates, 15% protein and 30% lipids. RESULTS: Group 3 presented increased HOMA-IR (M=2.5, SD=1.04) when compared with group 1 (M=1.5, SD=0.53) and group 2 (M=1.8, SD=0.58), p=0.04. Body mass index (p<0.0001), leptin (p<0.0001) and insulin (p=0.01) were higher in group 3 than in the other groups before and after the meal. Additionally, total ghrelin (p=0.003) and PYY3-36 (p=0.02) levels were lower in group 2 than in the other groups before and after the meal. After adjustment for body mass index, only the lower PYY3-36 level of group 2 remained statistically different from the other groups (p=0.01). CONCLUSION: Our study suggests that lower levels of PYY 3-36 are associated with binge eating in obese women.