Supplementation with cyanidin and delphinidin mitigates high fat diet-induced endotoxemia and associated liver inflammation in mice

Short-term supplementation of mice with cyanidin and delphinidin mitigates the metabolic endotoxemia and associated liver inflammation triggered by consumption of a high fat diet (HFD).

Chlorogenic Acid-Induced Gut Microbiota Improves Metabolic Endotoxemia

BackgroundCoffee can regulate glucose homeostasis but the underlying mechanism is unclear. This study investigated the preventive and therapeutic effects of chlorogenic acid (CGA), a polyphenol that is found in coffee, on obesity and obesity-related metabolic endotoxemia.MethodMale 4-week-old C57BL/6 mice were fed either normal chow or a high-fat diet or 20 weeks and half the mice in each group were gavaged with CGA. Oral glucose tolerance tests (OGTTs) and insulin tolerance tests (ITTs) were performed. Markers of inflammation and intestinal barrier function were assayed. The composition of the gut microbiota was analyzed by 16S rRNA high-throughput pyrosequencing. The role of CGA-altered microbiota in metabolic endotoxemia was verified by fecal microbiota transplantation.ResultsCGA protected against HFD-induced weight gain, decreased the relative weight of subcutaneous and visceral adipose, improved intestinal barrier integrity, and prevented glucose metabolic disorders and endotoxemia (P <0.05). CGA significantly changed the composition of the gut microbiota and increased the abundance of short chain fatty acid (SCFA)-producers (e.g., Dubosiella, Romboutsia, Mucispirillum, and Faecalibaculum) and Akkermansia, which can protect the intestinal barrier. In addition, mice with the CGA-altered microbiota had decreased body weight and fat content and inhibited metabolic endotoxemia.ConclusionCGA-induced changes in the gut microbiota played an important role in the inhibition of metabolic endotoxemia in HFD-fed mice.

Perilla Seed Oil Alleviates Gut Dysbiosis, Intestinal Inflammation and Metabolic Disturbance in Obese-Insulin-Resistant Rats

Background: High-fat diet (HFD) consumption induced gut dysbiosis, inflammation, obese-insulin resistance. Perilla seed oil (PSO) is a rich source of omega-3 polyunsaturated fatty acids with health promotional effects. However, the effects of PSO on gut microbiota/inflammation and metabolic disturbance in HFD-induced obesity have not been investigated. Therefore, we aimed to compare the effects of different doses of PSO and metformin on gut microbiota/inflammation, and metabolic parameters in HFD-fed rats. Methods: Thirty-six male Wistar rats were fed either a normal diet or an HFD for 24 weeks. At week 13, HFD-fed rats received either 50, 100, and 500 mg/kg/day of PSO or 300 mg/kg/day metformin for 12 weeks. After 24 weeks, the metabolic parameters, gut microbiota, gut barrier, inflammation, and oxidative stress were determined. Results: HFD-fed rats showed gut dysbiosis, gut barrier disruption with inflammation, increased oxidative stress, metabolic endotoxemia, and insulin resistance. Treatment with PSO and metformin not only effectively attenuated gut dysbiosis, but also improved gut barrier integrity and decreased gut inflammation. PSO also decreased oxidative stress, metabolic endotoxemia, and insulin resistance in HFD-fed rats. Metformin had greater benefits than PSO. Conclusion: PSO and metformin had the beneficial effect on attenuating gut inflammation and metabolic disturbance in obese-insulin resistance.

Effect of Diet and Dietary Components on the Composition of the Gut Microbiota

Diet and dietary components have profound effects on the composition of the gut microbiota and are among the most important contributors to the alteration in bacterial flora. This review examines the effects the “Western”, “plant-based”, “high-fat”, “medical ketogenic”, and “Mediterranean” diets have on the composition of the gut microbiota in both mice and human subjects. We show that specific dietary components that are commonly found in the “plant-based” and “Mediterranean” diet play a role in shifting the microbial composition. This review further evaluates the bacterial metabolites that are associated with diet, and their role in systemic inflammation and metabolic endotoxemia. Furthermore, the associations between diet/dietary components and altering bacterial composition, may lead to potential therapeutic targets for type II diabetes, obesity, and inflammatory diseases.

A Synthetic Peptide Designed to Neutralize Lipopolysaccharides Attenuates Metaflammation and Diet-Induced Metabolic Derangements in Mice

Metabolic endotoxemia has been suggested to play a role in the pathophysiology of metaflammation, insulin-resistance and ultimately type-2 diabetes mellitus (T2DM). The role of endogenous antimicrobial peptides (AMPs), such as the cathelicidin LL-37, in T2DM is unknown. We report here for the first time that patients with T2DM compared to healthy volunteers have elevated plasma levels of LL-37. In a reverse-translational approach, we have investigated the effects of the AMP, peptide 19-2.5, in a murine model of high-fat diet (HFD)-induced insulin-resistance, steatohepatitis and T2DM. HFD-fed mice for 12 weeks caused obesity, an impairment in glycemic regulations, hypercholesterolemia, microalbuminuria and steatohepatitis, all of which were attenuated by Peptide 19-2.5. The liver steatosis caused by feeding mice a HFD resulted in the activation of nuclear factor kappa light chain enhancer of activated B cells (NF-ĸB) (phosphorylation of inhibitor of kappa beta kinase (IKK)α/β, IκBα, translocation of p65 to the nucleus), expression of NF-ĸB-dependent protein inducible nitric oxide synthase (iNOS) and activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome, all of which were reduced by Peptide 19-2.5. Feeding mice, a HFD also resulted in an enhanced expression of the lipid scavenger receptor cluster of differentiation 36 (CD36) secondary to activation of extracellular signal-regulated kinases (ERK)1/2, both of which were abolished by Peptide 19-2.5. Taken together, these results demonstrate that the AMP, Peptide 19-2.5 reduces insulin-resistance, steatohepatitis and proteinuria. These effects are, at least in part, due to prevention of the expression of CD36 and may provide further evidence for a role of metabolic endotoxemia in the pathogenesis of metaflammation and ultimately T2DM. The observed increase in the levels of the endogenous AMP LL-37 in patients with T2DM may serve to limit the severity of the disease.

Metabolic endotoxemia is dictated by the type of lipopolysaccharide

Lipopolysaccharides (LPS) can promote metabolic endotoxemia, which is considered inflammatory and metabolically detrimental based on Toll-like receptor (TLR)4 agonists such as Escherichia coli-derived LPS. LPS from certain bacteria antagonize TLR4 yet contribute to endotoxemia measured by Endotoxin Units (EU). We found that E. coli LPS impaired gut barrier function and worsened glycemic control in mice, but equal doses of LPS from other bacteria did not. Matching the LPS dose from R. sphaeroides and E. coli by EU revealed that only E. coli LPS promoted dysglycemia, adipose inflammation, delayed intestinal glucose absorption, and augmented insulin and GLP-1 secretion. Metabolically beneficial endotoxemia promoted by R. sphaeroides LPS counteracted dysglycemia caused by an equal dose of E. coli LPS and promoted insulin sensitivity in obese mice. The concept of metabolic endotoxemia should be expanded beyond LPS load (EU) to include LPS characteristics, where the balance of deleterious and beneficial endotoxemia regulates host metabolism.

Role of Modified Diet and Gut Microbiota in Metabolic Endotoxemia in Mice

This study was aimed to investigate the effect of cultured gut microbiota (GM) from obese humans coupled HFD in inducing metabolic endotoxemia in humanized mice. In total, 30 strains were isolated from 10 stool samples of obese patients. Following morphological and biochemical characterization, 16S rRNA gene sequencing of six abundant isolates identified these as Klebsiella aerogenes, Levilactobacillus brevis, Escherichia coli, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis (MZ052089- MZ052094). In vivo trial using above six isolates, known as human gut microbiota (HGM), was performed for six months. Sixteen mice were distributed into four groups i.e., G1 (control) mice fed with chow diet, group 2 (G2) mice with HFD, group 3 (G3) mice with HFD + HGM and group 4 (G4) mice with chow diet + HGM. Body mass index (BMI) and plasma endotoxins were measured pre and post experiment. In vivo study revealed that HFD + HGM caused significant increase (3.9 g/cm at 20 weeks) in the body weight and BMI (0.4g/cm post experiment) of G3 mice compared to the other groups. One way ANOVA showed significantly higher level of endotoxins (2.41, 4.08 and 3.7 mmol/l) in mice groups G2, G3 and G4, respectively, indicating onset of metabolic endotoxemia. Cecal contents of experimental mice groups showed more diversified microbiota in mice groups G1 and G4 compared to G2 and G3 where high fat feeding alone and combined with obese gut microbiota caused a shift in microbial diversity as observed by all five strains belonging to either Firmicutes or Bacteriodetes phyla, respectively. In conclusion, current study reported that minor alteration in GM composition through HFD feeding and cultured GM transfer has significant impact in development of metabolic endotoxemia, possibly via modified intestinal permeability.