What is Akkermansia muciniphila?
Akkermansia muciniphila is a species of microbe found in the human gut microbiota.
Akkermansia muciniphila MucT was first isolated from human feces in 2004, in the laboratory of Prof. Willem M. de Vos (Wageningen University – The Netherlands) by Dr. Muriel Derrien. The identified strain was then deposited in the American Type Culture Collection (ATCC) under the reference ATCC® BAA-835™.
The characteristics of Akkermansia muciniphila
Akkermansia muciniphila is a gram-negative anaerobic bacterium belonging to the phylum Verrucomicrobia. It is a ‘commensal’ bacterium, meaning that it is naturally found in the gastrointestinal tract of humans and animals in relatively important quantities. In fact, it represents between 0.5 and 5% of all the bacteria colonizing the intestine. Far from being restricted to mammals, Akkermansia muciniphila is universally distributed in the animal kingdom. Indeed, it has been detected in birds, amphibians, fish and reptiles.
One key characteristic of Akkermansia muciniphila is its capacity to live in the mucus and use it. Indeed, it expresses a large panel of specific mucus-degrading enzymes. Thanks to these enzymes, it does not rely on dietary substances to feed itself. This ability provides Akkermansia muciniphila with a competitive advantage compared to other bacteria that do rely on fibers and other food particles as their main nutrient source. The specificity of Akkermansia muciniphila explains its distinctive niche: it lives in the mucus layer covering our intestinal epithelial cells. This means that the bacterium is located very close to the cells of our body and is able to communicate with them. (Cani & de Vos, 2017)
Where is Akkermansia muciniphila found?
Akkermansia muciniphila is found in the human gut from infancy. Its abundance then increases significantly up to adulthood. Akkermansia muciniphila cells have even been detected in human breast milk. The capacity of the bacterium to use human milk oligosaccharides (complex sugar molecules) as the only source of energy, carbon and nitrogen could explain its presence in breast milk and the breast tissue of lactating women. In fact, human milk may act as a carrier for Akkermansia muciniphila and transfer it from mother to infant. This explains why it can already be found in the infant intestine very early in life.
Two facts firmly strongly suggest that a symbiotic relationship exists between the bacterium and its hosts:
- The bacterium can be found in many different species.
- It has a close physical proximity to the intestinal wall.
Over the last decade, a large and important body of scientific literature (Reviewed in Derrien 2016) has emerged to confirm the following assumption:
The presence of Akkermansia muciniphila is associated with a healthier status in humans
(Derrien 2016, Akkermansia muciniphila and its role in regulating host functions).
Indeed, numerous studies have found that Akkermansia muciniphila was positively associated with:
- a healthy gut lining;
- reduced metabolic disorders;
- decreased low-grade inflammation.
Akkermansia muciniphila is highly abundant in lean and non-diabetic individuals. In contrast, it has been found to be lower in several conditions such as obesity, diabetes, intestinal inflammation, liver diseases, or chronic alcohol consumption. This is associated with an altered gut barrier function which eventually triggers low-grade inflammation and metabolic disorders.
Moreover, in the context of obesity-associated disorders, Akkermansia muciniphila is systematically found to be inversely correlated with cardiometabolic risk factors. These factors include insulin resistance, serum lipids, BMI and adiposity. In contrast, it is positively correlated with protective markers such as high-density lipoprotein (HDL, or “good” cholesterol). Furthermore, the baseline intestinal levels of the bacterium in overweight or obese subjects could be a potential prognostic marker for predicting the success of dietary interventions. Indeed, after a 6-week low-calorie diet, obese individuals with higher baseline Akkermansia muciniphila all displayed an improvement of parameters related to glucose tolerance and to other cardiometabolic risk factors. (Derrien, 2016)