Periodontal dysbiosis boosts insulin resistance in mice

Last Updated: 2016-02-23

By David Douglas

NEW YORK (Reuters Health) - Work in a murine model indicates that periodontitis can aggravate glucose intolerance and insulin resistance induced by a high-fat diet, according to French researchers.

Dr. Rémy Burcelin told Reuters Health by email that a novel mechanism of type 2 diabetes has been uncovered: Lipopolysaccharides produced by bacteria such as Porphyromonas gingivalis (Pg) "that infect the periodontal cavity in the mouth activate specifically the oral immune system to trigger insulin resistance and type 2 diabetes."

In their paper, online February 12 in Gut, Dr. Burcelin of the Hospital of Rangueil in Toulouse and colleagues say they infected the periodontal tissue of mice with pathogens including Pg, Fusobacterium nucleatum and Prevotella intermedia. The mice were then fed a diabetogenic fat-enriched diet for up to three months.

The periodontitis induced periodontal microbiota dysbiosis largely without affecting gut microbiota; it also impaired glucose metabolism.

Moreover, the transfer of cervical lymph-node cells from infected to naive mice guarded against periodontitis-aggravated metabolic disease. In addition, treatment with inactivated Pg prior to periodontal infection induced specific antibodies against Pg and protected mice from periodontitis-induced dysmetabolism.

The researchers further established that a one-month subcutaneous chronic infusion of low levels of lipopolysaccharides from Pg mimicked the impact of periodontitis on both immune and metabolic parameters.

The team notes that "insulin resistance seems to be secondary to the onset of an inflammatory process in which innate and adaptive immune responses may promote inflammatory reactions driven by gut microbiota."

"Although the nutritional stress and the gut microbiota dysbiosis can induce metabolic diseases per se," they add, "we further show that a concomitant periodontal disease triggers the regional adaptive immune system, which enhances insulin resistance."

An anti-inflammatory approach directed against the regional immune system could reduce the incidence of insulin resistance and type 2 diabetes, the researchers note. "A vaccination strategy against Pg may reduce the impact of periodontitis on glucose metabolism," they conclude.

SOURCE: bit.ly/1L8uSc9

Gut 2016.