Bletilla striata oligosaccharides improve metabolic syndrome through modulation of gut microbiota and intestinal metabolites in high fat diet-fed mice

As traditional Chinese medicine, Bletilla striata has been widely applied to clinical treatment for its unique pharmacological profiles. This study aimed to investigate the beneficial role of Bletilla striata oligosaccharides (BO) in improving the metabolic syndrome by regulation of gut microbiota and intestinal metabolites. Treatment of HFD-fed mice with BO prevented weight gain, reversed the glucose intolerance and insulin resistance, and inhibited adipocyte hypertrophy. BO-treated mice also suppressed chronic inflammation and protected intestinal barrier from damage. These effects were linked to the reversal of gut microbiota dysbiosis, which contributed to the homeostasis of intestinal metabolites including bile acids, short-chain fatty acids and tryptophan catabolites. The depletion and reconstitution of intestinal flora from BO- or HFD-treated mice confirmed the significance of gut microbiota in regulation of HFD-induced metabolic disorders. We demonstrated for the first time that BO improved metabolic syndrome through the regulation of gut microbiota and intestinal metabolites. The modulation initiated by BO represents a promising strategy for treatment of obesity and related metabolic diseases.

Triclosan and prescription antibiotic exposures and enterolactone production in adults

BACKGROUND

The gut microbiome plays an important role in the development of disease. The composition of the microbiome is influenced by factors such as mode of delivery at birth, diet and antibiotic use, yet the influence of environmental chemical exposures is largely unknown. The antimicrobial compound triclosan, found in many personal care products and widely detected in human urine, is an environmental exposure for which systemic microbiotic effects may be of particular interest. To investigate the relationship between triclosan and gut microflora, we assessed the association between triclosan and enterolactone, an intestinal metabolite that is produced via bacterial transformation of dietary lignans (seeds, nuts) and has known susceptibility to oral antibiotics.

METHODS

We examined urinary triclosan and enterolactone for 2005-2008 U.S. National Health and Nutrition Examination Survey subjects, aged ≥20 years (n=3041). We also examined the association between prescription antibiotic use and enterolactone to confirm its susceptibility to changes in bacterial composition of the body. Associations between natural log-transformed enterolactone and (1) detected vs. not detected (<2.3 ng/mL) triclosan, (2) triclosan quintiles (Q1-Q5), and (3) any vs. no antibiotics were estimated with multiple linear regression, adjusting for sex, age, race, body mass index, poverty income ratio, education, fiber intake, bowel movement frequency, cotinine and creatinine (n=2441).

RESULTS

Triclosan was detected in 80% of subjects (range: <2.3-3620 ng/mL), while enterolactone was detected in >99% of subjects (range: <0.1-122,000 ng/mL). After adjustment, enterolactone was not associated with triclosan (detect vs. non-detect: β= 0.07 (95% CI: -0.15, 0.30); Q5 (≥104.5 ng/mL) vs. Q1 (none): β= 0.06 (95% CI: -0.21, 0.34)). In sex-stratified analyses, triclosan was associated with higher enterolactone in women (detect vs. non-detect: β= 0.31 (95% CI: -0.07, 0.70), but not men β= -0.18 (95% CI: -0.47, 0.11). However, any antibiotic use (n=112), as compared to no antibiotic use, was associated with significantly lower enterolactone (β=-0.78 (95%CI: -1.22, -0.36)), with no sex-specific effects. This association was driven by inverse associations with the following antibiotic classes: macrolide derivatives, quinolones, sulfonamides, and lincomycin derivatives.

CONCLUSIONS

Antibiotics, but not triclosan, are negatively associated with urinary enterolactone. Antibiotics may reduce enterolactone by killing certain gut bacteria. At levels detected in the U.S., triclosan does not appear to be acting similarly, despite broad antimicrobial properties. Additional study of determinants of triclosan exposure and enterolactone production may be needed to better understand positive associations among women.