The lions share of the risk (~70%) for developing MS is attributable to environmental risk, while genetics explains bulk of the remaining risk. The environmental risk factors studied in MS have been manifold, ranging from the latitude effect, to viruses, and may well explain some of the heterogeneity that we observe.
For some time now, researchers have been looking at an imbalance in the gut microbiome or their maladaptation in MS cases versus controls. The findings suggest that the interaction between the microbiome and the host (you) may be reciprocal.
Here, a group of investigators have been investigating a particular human gut commensal, Prevotella histicola, a gram negative bacterium. In the past they have found that P. histicola suppresses induction of disease in the mouse model of MS, decreasing the presence of pro-inflammatory T cells (Th1 and Th17), whilst increasing the frequency of the regulatory immune cell population. To further consolidate their findings they have taken this work a step further, asking the question whether targeting P. histicola could be a novel therapeutic strategy in MS? To this effect, they have pitched against glatiramer acetate (aka Copaxone) in a proof of concept battle.
They found that P. histicola suppresses EAE as efficiently as Copaxone in their model (see figure above). As before, P. histicola alone or in combination with Copaxone increased the regulatory cell population, while at the same time decreasing pro-inflammatory cells, suggesting that P. histicola may be immunomodulatory. However, it would seem Copaxone administration failed to alter the number of Th1/Th17 pro-inflammatory cells, whilst P. histicola had a direct effect (see figure below).
So I would say, watch this space. Clearly, this is a novel therapeutic avenue that needs to be trialed in MS, possibly at the early stages of the disease.
Front Immunol. 2019 Mar 22;10:462. doi: 10.3389/fimmu.2019.00462. eCollection 2019.
Prevotella histicola, A Human Gut Commensal, Is as Potent as COPAXONE® in an Animal Model of Multiple Sclerosis.
Shahi SK, Freedman SN, Murra AC, Zarei K, Sompallae R, Gibson-Corley KN, Karandikar NJ, Murray JA, Mangalam AK1.
Multiple sclerosis (MS) is a demyelinating disease of the central nervous system. We and others have shown that there is enrichment or depletion of some gut bacteria in MS patients compared to healthy controls (HC), suggesting an important role of the gut bacteria in disease pathogenesis. Thus, specific gut bacteria that are lower in abundance in MS patients could be used as a potential treatment option for this disease. In particular, we and others have shown that MS patients have a lower abundance of Prevotella compared to HC, whereas the abundance of Prevotella is increased in patients that receive disease-modifying therapies such as Copaxone® (Glatiramer acetate-GA). This inverse correlation between the severity of MS disease and the abundance of Prevotella suggests its potential for use as a therapeutic option to treat MS. Notably we have previously identified a specific strain, Prevotella histicola (P. histicola), that suppresses disease in the animal model of MS, experimental autoimmune encephalomyelitis (EAE) compared with sham treatment. In the present study we analyzed whether the disease suppressing effects of P. histicola synergize with those of the disease-modifying drug Copaxone® to more effectively suppress disease compared to either treatment alone. Treatment with P. histicola was as effective in suppressing disease as treatment with Copaxone®, whereas the combination of P. histicola plus Copaxone® was not more effective than either individual treatment. P. histicola-treated mice had an increased frequency and number of CD4+FoxP3+ regulatory T cells in periphery as well as gut and a decreased frequency of pro-inflammatory IFN-γ and IL17-producing CD4 T cells in the CNS, suggesting P. histicola suppresses disease by boosting anti-inflammatory immune responses and inhibiting pro-inflammatory immune responses. In conclusion, our study indicates that the human gut commensal P. histicola can suppress disease as efficiently as Copaxone® and may provide an alternative treatment option for MS patients.