isoxanthohumol and Insulin-Resistance

Polyphenols have health-promoting effects, such as improving insulin resistance. Isoxanthohumol (IX), a prenylated flavonoid found in beer hops, has been suggested to reduce obesity and insulin resistance; however, the mechanism remains unknown.. High-fat diet-fed mice were administered IX. We analyzed glucose metabolism, gene expression profiles and histology of liver, epididymal adipose tissue and colon. Lipase activity, fecal lipid profiles and plasma metabolomic analysis were assessed. Fecal 16s rRNA sequencing was obtained and selected bacterial species were used for in vitro studies. Fecal microbiota transplantation and monocolonization were conducted to antibiotic-treated or germ-free (GF) mice.. The administration of IX lowered weight gain, decreased steatohepatitis and improved glucose metabolism. Mechanistically, IX inhibited pancreatic lipase activity and lipid absorption by decreasing the expression of the fatty acid transporter CD36 in the small intestine, which was confirmed by increased lipid excretion in feces. IX administration increased markers of intestinal barrier function, including thickening the mucin layer and increasing caludin-1, a tight-junction related protein in the colon. In contrast, the effects of IX were nullified by antibiotics. As revealed using 16S rRNA sequencing, the microbial community structure changed with a significant increase in the abundance of Akkermansia muciniphila in the IX-treated group. An anaerobic chamber study showed that IX selectively promoted the growth of A. muciniphila while exhibiting antimicrobial activity against some Bacteroides and Clostridium species. To further explore the direct effect of A. muciniphila on lipid and glucose metabolism, we monocolonized either A. muciniphila or Bacteroides thetaiotaomicron to GF mice. A. muciniphila monocolonization decreased CD36 expression in the jejunum and improved glucose metabolism, with decreased levels of multiple classes of fatty acids determined using plasma metabolomic analysis.. Our study demonstrated that IX prevents obesity and enhances glucose metabolism by inhibiting dietary fat absorption. This mechanism is linked to suppressing pancreatic lipase activity and shifts in microbial composition, notably an increase in A. muciniphila. These highlight new treatment strategies for preventing metabolic syndrome by boosting the gut microbiota with food components.

Topics: Animals; Diet, High-Fat; Dietary Fats; Glucose; Insulin Resistance; Lipase; Mice; Obesity; RNA, Ribosomal, 16S; Verrucomicrobia

To assess whether the hop-derived polyphenol isoxanthohumol suppresses insulin resistance by changing the intestinal microbiota.. Male C57BL/6J mice (7 weeks of age) were divided into five groups (n = 9-10): Normal Diet (ND), High Fat Diet (HFD), HFD + low dose isoxanthohumol (0.01%IX), HFD + medium dose isoxanthohumol (0.03% IX), and HFD + high dose isoxanthohumol (0.1% IX). Oral glucose tolerance tests (OGTTs) were performed at 4 and 8 weeks, and insulin tolerance tests (ITTs) were performed at 13 weeks. 16S rRNA gene sequencing analyses revealed the fecal microbiota profiles, and the relative abundance of Akkermansia muciniphila and Clostridium cluster XI was calculated by qRT-PCR. Plasma lipopolysaccharide (LPS) levels were measured by ELISA, and mRNA expression levels of tumor necrosis factor (TNF)-α, and interleukin (IL)-1β in epididymal adipose tissues were measured by qRT-PCR.. Isoxanthohumol showed antibacterial activity towards several bacterial species and mitigated impaired glucose tolerance and insulin resistance induced by the HFD in a dose-dependent manner, as shown by OGTTs and ITTs. The concentration of phylum Verrucomicrobia bacteria dramatically increased in the 0.1% IX group, the relative abundance of A. muciniphila increased, and that of Clostridium cluster XI decreased. Moreover, the intake of isoxanthohumol decreased the levels of plasma LPS and mRNA expression of TNF-α and IL-1β in epididymal adipose tissues.. We found that isoxanthohumol can suppress HFD-induced insulin resistance by changing the intestinal microbiota and reducing the expression of inflammation factors.

Topics: Animals; Chronic Disease; Diet, High-Fat; Flavonoids; Gastrointestinal Microbiome; Humulus; Inflammation; Inflammation Mediators; Insulin Resistance; Male; Mice; Mice, Inbred C57BL; Xanthones