Molecular Nutrition & Food Research最新文献

Scope: Type 2 diabetes mellitus (T2DM) is a metabolic disease with a major global public health effect. Rambutan peel polyphenols (RPPs) have been reported to exert hypoglycemic activity. However, few studies have been explored from the viewpoint of gut microbiota and its metabolites.

Methods and results: RPPs are administered by gavage to a mice model of T2DM established by using a high-fat diet combined with streptozotocin. It finds that RPPs treatment alleviates hyperglycemia symptoms by improving glucolipid metabolism and liver function. Immunohistochemistry indicates that the antihyperglycemic effect of RPPs is regulated by the IRS-1/PI3K/AKT/GSK3β signaling pathway. RPPs treatment remodels the structure of gut microbiota (Odoribacter, Lachnospiraceae_NK4A136_group, Lactobacillus, Turicibacter, Erysipelatoclostridium, and Tuzzerella) and enriches the metabolites (RPPs-derived urolithins, short-chain fatty acids, dehydrocholic acid, (+)-catechin, dihydroberberine, pterostilbene, and artesunate) associated with diabetes regulation in T2DM mice. The effects of RPPs in ameliorating glycolipid metabolism disorders are correlated with differential gut microbiota and metabolites.

Conclusion: The gut microbiota and its metabolites are key targets for the hypoglycemic effects of RPPs.

Scope: Curcumin (Cur), with diverse pharmacological properties, shows anti-obesity, immunomodulatory, and anti-inflammatory effects. Its role in ulcerative colitis complicated by obesity remains unclear.

Methods and results: Here, colitis is induced in obese mice using dextran sulfate sodium (DSS), followed by administration of Cur at a dosage of 100 mg kg⁻¹ for 14 days. Cur effectively alleviates DSS-induced colitis in obese mice, accompanied by an increase in body weight and survival rate, reduction in disease activity index, elongation of the colon, decrease in colonic weight, and improvements in ulcer formation and inflammatory cell infiltration in colonic tissues. Additionally, Cur effectively improves lipid metabolism and the composition of the gut microbiota, and enhances mucosal integrity and boosts anti-oxidative stress capacity in obese mice with colitis. Importantly, Cur is effective in improving the homeostasis of memory T cells in obese mice with colitis. Furthermore, Cur regulates inflammatory cytokines expression and inhibits activation of the JAK2/STAT signaling pathway in colonic tissues of obese mice with colitis.

Conclusions: Cur alleviates colitis in obese mice through a comprehensive mechanism that improves lipid metabolism, modulates gut microbiota composition, enhances mucosal integrity and anti-oxidative stress, balances memory T cell populations, regulates inflammatory cytokines, and suppresses the JAK2/STAT signaling pathway.

The progression of obesity involves several molecular mechanisms that are closely associated with the pathophysiological response of the disease. Endoplasmic reticulum (ER) stress is one such factor. Lipotoxicity disrupts endoplasmic reticulum homeostasis in the context of obesity. Furthermore, it induces ER stress by activating several signaling pathways via inflammatory responses and oxidative stress. ER performs crucial functions in protein synthesis and lipid metabolism; thus, triggers such as lipotoxicity can promote the accumulation of misfolded proteins in the organelle. The accumulation of these proteins can lead to metabolic disorders and chronic inflammation, resulting in cell death. Thus, alternatives, such as flavonoids, amino acids, and polyphenols that are associated with antioxidant and anti-inflammatory responses have been proposed to attenuate this response by modulating ER stress via the administration of nutrients and bioactive compounds. Decreasing inflammation and oxidative stress can reduce the expression of several ER stress markers and improve clinical outcomes through the management of obesity, including the control of body weight, visceral fat, and lipid accumulation. This review explores the metabolic changes resulting from ER stress and discusses the role of nutritional interventions in modulating the ER stress pathway in obesity.

The gastrointestinal tract (GIT) harbors the largest group of microbiotas among the microbial communities of the human host. The resident organisms typical of a healthy gut are well adapted to the gastrointestinal environment while alteration of these populations can trigger disorders that may affect the health and well-being of the host. Various investigations have applied different tools to study bacterial communities in the gut and their correlation with gastrointestinal disorders such as inflammatory bowel disease (IBD), obesity, and diabetes. This study proposes fluorescent in situ hybridization, combined with flow cytometry (FISH-FLOW), as an alternative approach for phylum level identification of Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria and quantification of target bacteria from the GIT based on analysis of fecal samples, where results are validated by quantitative polymerase chain reaction (qPCR) and 16S ribosomal ribonucleic acid (16s rRNA) sequencing. The results obtained via FISH-FLOW experimental approach show high specificity for the developed probes for hybridization with the target bacteria. The study, therefore, suggests the FISH-FLOW as a reliable method for studying bacterial communities in the gut with results correlating well with those of metagenomic investigations of the same fecal samples.