ModulAtion of Gut Microbiota Through Nutritional Interventions in Behcet's Syndrome pAtients: the MAMBA Study

Background / State of Art:

Behçet's syndrome (BS) is a systemic inflammatory disorder characterized by a wide range of potential clinical manifestations with no gold-standard therapy. Although BS is usually not a life-threatening condition, mortality can be associated with vascular-thrombotic and neurological affections.

A recent study by our group, for the first time, provided evidence of a peculiar gut microbiota (GM) dysbiosis in BS patients, with reduced biodiversity, and decrease in short-chain fatty acid (SCFA)-producers and butyrate production. In light of this, controlled dietary interventions specifically designed to favor the increase of butyrate-producing members of the GM may support the recovery of a healthy GM ecosystem. Lacto-ovo-vegetarian diet is characterized by abstention from consuming meat and meat products, poultry, seafood and flesh from any other animal and by a large amount of plant- derived foods. This dietary pattern has been largely demonstrated to be beneficial for both patients with an established disease and for subjects with traditional risk factors for chronic diseases. Indeed, dietary patterns rich in plant-based food have been found to promote a more favorable GM profile, according to the high amount of dietary fiber and fermentable substrate, which are sources of metabolic fuel for GM fermentation that, in turn, result in end products - mainly SCFA - that are key microbial metabolites with a multifactorial role on the host health.

Hypothesis and Specific aims:

Although the pathogenesis of BS is currently unknown, it has been recently classified at the crossroad between autoimmune and autoinflammatory syndromes. GM has been found to deeply influence our metabolic and immunological health, and specific perturbed GM configurations have been indicating a fascinating link between intestinal microbes and health status. A recent study from our group showed that a peculiar dysbiosis of the GM ecosystem is present also in patients with BS, corresponding to specific changes in the profiles of SCFA production. In particular, the GM ecosystem in BS showed a low biodiversity, in line with several other chronic disorders. Moreover, a significant depletion of well- known butyrate producers, Roseburia and Subdoligranulum, and a corresponding decrease of butyrate production in BS patients was demonstrated. Butyrate - which is the preferred fuel for colonocytes - is able to induce T regulatory cell differentiation via several mechanisms, so the butyrate impairment in BS patients could favor a reduced T regulatory cell- mediated control, thus promoting a powerful immuno-pathological T cell responses.