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Professor Sergio Baranzini: Genetics, environmental factors and the role of gut bacteria in MS


Professor Baranzini discusses recent work in his lab on gut bacteria and its association with the susceptibility and progression of MS.

Genetic studies have shown that MS segregates in certain families and in certain populations. The global MS genetics consortium has mapped nearly 200 regions of the genome that convey susceptibility (n=50,000). They also assessed the extent of susceptibility that can be attributed to genetic variation. For example identical twins share 100% genetic code, but only have a 20-25% rate of both acquiring MS. This suggests that both genetic and environmental factors are at play.

Prof Baranzini is evaluating gut bacteria, which has long been associated with mediating immune responses. There is a wide variety of gut bacteria in humans, and imbalances in bacteria may be associated with susceptibility to MS. He has found a good correlation between the relative abundances of different types of gut bacteria with immune responses. Some bacteria found in abundance in MS patients cause excessive cell stimulation in culture, whereas some found in low abundance in the gut are necessary for modulating immune response to keep the immune system in check.

The International MS Microbiome Study is a new global consortium that will study 2000 MS patients and 2000 controls to establish the structural composition of the microbiome in MS and to assess the immunological effect in in vitro and in vivo models. Their goal is to assess genetic and environmental factors (such as diet and chemical exposure), on the pathogenesis of MS, and to use this information to develop targeted, effective and safe therapies for MS.

The interview was recorded at the annual ECTRIMS meeting from 14-17 September 2016 in London, United Kingdom.

Professor Sergio Baranzini, Department of Neurology, University of California, San Francisco, USA.