Akkermansia muciniphila is one of the many microbes that live in our intestines. This bacterium, which feeds on the intestine’s mucus lining, comprises between 3 and 5 percent of the gut microbes of healthy mammals. There is an inverse correlation between body weight and abundance of A. muciniphila in mice and humans. In a paper published in the Proceedings of the National Academy of Sciences, Patrice Cani of the Catholic University of Louvain in Belgium and his colleagues reveal that levels of this bacterium are very low in mice genetically predisposed to obesity. Restoring Akkermansia to normal levels leads to fat reduction and reduced insulin resistance.
Cani and his team found that genetically obese mice had 3,300 times less A. muciniphila in their intestines than healthy mice. When they fed mice, regardless of body weight, a high-fat diet, levels of the bacterium fell 100 times.
The researchers were able to restore normal Akkermansia levels to mice on a high fat diet by feeding them liveAkkermansia or by giving them oligofructose prebiotics.
When normal levels were established, the mice lost weight and developed a better fat to lean mass ratio. Insulin resistance and adipose tissue inflammation, all associated with obesity and type 2 diabetes, also decreased. Metabolic endotoxemia, another related condition, was abolished, while fasting hyperglycemia was reversed. There was an increase in levels ofendocannabinoids, which help control blood glucose levels, the gut barrier and inflammation.
Intestinal mucus, which normally erodes with weight gain, became thicker. The mucus that lines the intestines acts as a barrier to harmful microbes, so A. muciniphila could play an important role in preventing inflammation and other disease triggers.
Feeding the mice heat-killed Akkermansia had no effect.
Cani believes Akkermansia sends a signal to the cells of the intestinal lining that causes them to produce more mucus and more anti-microbial molecules. This results in a mutually beneficial relationship between the bacterium and its host; the host provides Akkermansia with food, and Akkermansia protects the host from infection.
Although a high fat diet had a strong effect on gut microbiota composition, giving the mice A. muciniphila did not significantly affect the overall microbiota profile. This indicates that this species alone was probably responsible for the beneficial changes that occurred.
When the researchers gave obese mice Lactobacillus plantarum, a bacterium often found in probiotics, there was no effect.
Cani says scientists should study whether A. muciniphila could help treat obesity and related metabolic disorders in humans.
Journal reference: Proceedings of the National Academy of Sciences