Manipulation of gut microbiota in obesity influences metabolic outcomes

A study in the most recent issue of Gut reports divergent metabolic outcomes arising from targeted manipulation of the gut microbiota in diet-induced obesity.

The gut microbiota is an environmental regulator of fat storage and adiposity.

Whether the microbiota represents a realistic therapeutic target for improving metabolic health is unclear.

Dr Eileen Murphy from Pittsburgh, USA explored 2 antimicrobial strategies for their impact on metabolic abnormalities in murine diet-induced obesity, including oral vancomycin and a bacteriocin-producing probiotic.

Males were fed a low-fat or a high-fat diet for 20 weeks with/without vancomycin by gavage at 2 mg/day, or with L salivarius UCC118Bac+ or the bacteriocin-negative derivative L salivarius UCC118Bac.

The researchers reported that the compositional analysis of the microbiota was by 16S rDNA amplicon pyrosequencing.

Analysis of the gut microbiota showed that vancomycin treatment led to significant reductions in the proportions of Firmicutes and Bacteroidetes, and a dramatic increase in Proteobacteria, with no change in Actinobacteria.

The team found that vancomycin-treated high-fat-fed mice gained less weight over the intervention period despite similar caloric intake, and had lower fasting blood glucose, plasma TNFα and triglyceride levels compared with diet-induced obese controls.

Vancomycin-treated high-fat-fed mice gained less weight

Gut

The bacteriocin-producing probiotic had no significant impact on the proportions of Firmicutes but resulted in a relative increase in Bacteroidetes and Proteobacteria, and a decrease in Actinobacteria compared with the non-bacteriocin-producing control.

The researchers noted no improvement in metabolic profiles in probiotic-fed diet-induced obese mice.

Dr Murphy's team concludes, "Both vancomycin and the bacteriocin-producing probiotic altered the gut microbiota in diet-induced obese mice, but in distinct ways."

"Only vancomycin treatment resulted in an improvement in the metabolic abnormalities associated with obesity thereby establishing that while the gut microbiota is a realistic therapeutic target, the specificity of the antimicrobial agent employed is critical."