Published: 24 June 2015
There is a strong association between the gut microbiome and the human host. Different characteristics of the microbiome, including bacterial diversity and the abundance of specific bacterial groups, may play a role in the development of obesity and related complications. Among those, the role of the gut bacterial species Akkermansia muciniphila was highlighted for maintaining metabolic health in mouse models.
Because little is known in humans, Karine Clément’s team at Institute of Cardiometabolism and Nutrition (INSERM- University Pierre et Marie Curie), have explored the link between markers of human health, diet, microbiota and the intestinal abundance of Akkermansia muciniphila in 49 overweight and obese subjects.
They found that intestinal A. muciniphila is associated with better insulin sensitivity. Obese subjects that initially had higher abundance of A. muciniphila experienced greater benefits from calorie restriction in terms of waist circumference and cholesterol reduction, and insulin sensitivity improvement.
Most importantly, the healthiest participants before and after the intervention not only had more A. muciniphila but also the most diverse repertoire of bacterial species in the gut. These results demonstrate the importance of studying the gut microbiome as an ecosystem rather than having a narrow focus on specific bacterial groups. Further, our findings support future investigation of A. muciniphila as a potential marker or therapeutic target of obesity-related diseases.
Microbiome research is actively advancing to address the many questions that remain regarding its relationship with human health. An integrative approach is required for this investigation because the microbiome interacts with the host and the environment in the development of obesity and its co-morbidities. So far, evidence suggests that health may be restored partly through modification of the gut ecosystem, and therefore it is critical to identify gut microbial patterns and signatures that characterize different stages of disease and may help in their diagnosis, treatment and prevention.
Individuals with obesity and type 2 diabetes differ from lean and healthy individuals in their abundance of certain gut microbial species and microbial gene richness. Abundance of Akkermansia muciniphila, a mucin-degrading bacterium, has been inversely associated with body fat mass and glucose intolerance in mice, but more evidence is needed in humans. The impact of diet and weight loss on this bacterial species is unknown. Our objective was to evaluate the association between faecal A. muciniphila abundance, faecal microbiome gene richness, diet, host characteristics, and their changes after calorie restriction (CR).
The intervention consisted of a 6-week CR period followed by a 6-week weight stabilisation diet in overweight and obese adults (N=49, including 41 women). Faecal A. muciniphila abundance, faecal microbial gene richness, diet and bioclinical parameters were measured at baseline and after CR and weight stabilisation.
At baseline A. muciniphila was inversely related to fasting glucose, waist-to-hip ratio and subcutaneous adipocyte diameter. Subjects with higher gene richness and A. muciniphila abundance exhibited the healthiest metabolic status, particularly in fasting plasma glucose, plasma triglycerides and body fat distribution. Individuals with higher baseline A. muciniphila displayed greater improvement in insulin sensitivity markers and other clinical parameters after CR. These participants also experienced a reduction in A. muciniphila abundance, but it remained significantly higher than in individuals with lower baseline abundance. A. muciniphila was associated with microbial species known to be related to health.
A. muciniphila is associated with a healthier metabolic status and better clinical outcomes after CR in overweight/obese adults. The interaction between gut microbiota ecology and A. muciniphila warrants further investigation.
Trial registration number NCT01314690.
Authors and reference
Dao MC, Everard A, Aron-Wisnewsky J, Sokolovska N, Prifti E, Verger EO, Kayser B, Levenez F, Chilloux J, Hoyles L, MICRO-Obes Consortium, Dumas ME, Rizkalla SW, Doré J, Cani PD, Clément K. Akkermansia muciniphila and improved metabolic health during a dietary intervention in obesity: relationship with gut microbiome richness and ecology. Gut 2015;