Gut Microbiota and Behcet's Syndrome: a Dietary Intervention Trial (MAMBA Study)

  • End date
    Jan 22, 2022
  • participants needed
  • sponsor
    Azienda Ospedaliero-Universitaria Careggi
Updated on 22 January 2021
mediterranean diet
skin lesions
inflammatory disorder
eye disease
short-chain fatty acids


Behcet's syndrome (BS) is an idiopathic, chronic, multi-systemic inflammatory disorder characterized by ocular disease, skin lesions, vascular, neurological and gastrointestinal involvement. A recent study showed a peculiar dysbiosis of gut microbiota (GM) in BS patients, with specific changes in the profiles of short-chain fatty acids, especially butyrate. Over the last few years, a growing interest on the role of GM in metabolic disturbances has been manifested. Diet is one of the major factors driving the GM composition and functionality. In this context, the influence of diets generally recognized healthy on GM has been explored, but consistent data on autoimmune and inflammatory diseases are not available. The aim of this intervention study is to investigate whether a lacto-ovo-vegetarian diet enriched in substrates with potential for butyrate production or a Mediterranean diet supplemented with oral butyrate could be beneficial for GM and metabolic risk profile in BS.


Background / State of Art:

Behcet'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.

In this context, over the last years, growing evidence suggested that high-fiber dietary patterns are able to promote a more favorable GM profile, and are key mediators of microbial diversity. In particular, it has recently been demonstrated that high adherence to a lacto-ovo-vegetarian diet - including high intake of non-refined cereals, fruit, vegetables and legumes - is associated with a beneficial GM profile, with enrichment in fiber-degrading bacteria and increase of fecal SCFA. In a similar way, other dietary patterns have been shown to modulate GM dysbiosis, by supporting the recovery of a balanced microbial community of health-promoting SCFA-producing members with the decrease of pro-inflammatory groups. Furthermore, current evidence indicates that the consumption of certain fibers - such as inulin and resistant starch - leads to specific GM rearrangements with the production of more butyrate than others in humans.

All these findings let hypothesize that the adherence to a controlled dietary profile such as lacto-ovo-vegetarian diet, possibly enriched in substrates with potential for butyrate production may select butyrate-producing bacteria - especially Roseburia spp. (Clostridium cluster XIVa) and Faecalibacterium prausnitzii (Clostridium cluster IV)- so reversing the pro- inflammatory dysbiosis observed in BS.

Preliminary Data:

A recent study by our group showed that a peculiar dysbiosis of the GM ecosystem is present in patients with BS, corresponding to specific changes in the profiles of SCFA production. By strengthening this dysbiotic GM structure, a significant decrease of fecal butyrate production was found in BS patients. More recently, a high percentage of Th1/Th17 cells at gut mucosal level in BS patients was observed, thus suggesting a reduced T regulatory activity, probably mediated by reduced levels of butyrate (unpublished data).

Specific Aim 1: To conduct a dietary intervention randomized controlled trial in order to investigate whether a lacto-ovo-vegetarian diet enriched in substrates with potential for butyrate production or a Mediterranean diet supplemented with 2 g/day of butyrate could be beneficial for GM and for the amelioration of the clinical manifestations and disease severity of patients with BS.

Specific Aim 2: To evaluate the effects of these interventions on: inflammatory parameters, circulating biomarkers of disease, endogenous butyrate production, and oxidative stress markers.

Specific Aim 3: To validate and extend our preliminary results on GM ecosystem dysbiosis in BS patients

Condition Behcet's Syndrome, Anterior uveitis, behcet's disease
Treatment Mediterranean diet, Vegetarian diet, Vegetarian diet, Mediterranean diet with butyrate
Clinical Study IdentifierNCT03962335
SponsorAzienda Ospedaliero-Universitaria Careggi
Last Modified on22 January 2021


Yes No Not Sure

Inclusion Criteria

Is your age between 18 yrs and 65 yrs?
Gender: Male or Female
Do you have Behcet's Syndrome?
Do you have any of these conditions: Anterior uveitis or Behcet's Syndrome or behcet's disease?
Behcet syndrome
Age 18-65 years
Willing to give informed consent
Willing to participate in a study where one of the proposed dietary profile is a vegetarian pattern

Exclusion Criteria

Pregnancy or lactation
Concomitant presence of serious illness or unstable condition (autoimmune diseases; chronic viral infections; malignancies, recent myocardial infarction, chronic liver disease, inflammatory bowel diseases)
Current or recent (past 6 months) participation in weight loss treatment program or use of weight loss medication
Adoption of a vegetarian diet for the past 3 months
Clear my responses

How to participate?

Step 1 Connect with a site
What happens next?
  • You can expect the study team to contact you via email or phone in the next few days.
  • Sign up as volunteer to help accelerate the development of new treatments and to get notified about similar trials.

You are contacting

Investigator Avatar

Primary Contact


Phone Email

Please verify that you are not a bot.

Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

Learn more

If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

Learn more

Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

Learn more

Similar trials to consider


Browse trials for

Not finding what you're looking for?

Every year hundreds of thousands of volunteers step forward to participate in research. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.

Sign up as volunteer

user name

Added by • 



Reply by • Private

Lorem ipsum dolor sit amet consectetur, adipisicing elit. Ipsa vel nobis alias. Quae eveniet velit voluptate quo doloribus maxime et dicta in sequi, corporis quod. Ea, dolor eius? Dolore, vel!

  The passcode will expire in None.

No annotations made yet

Add a private note
  • abc Select a piece of text from the left.
  • Add notes visible only to you.
  • Send it to people through a passcode protected link.
Add a private note