Dietary conjugated linoleic acid links reduced intestinal inflammateon to amelioration of CNS autoimmunity

A close interaction between gut immune responses and distant organ-specific autoimmunity including the CNS in multiple sclerosis has been established in recent years. This so-called gut-CNS axis can he shaped by dietary factors, either directly or via indirect modulation of the gut microbiome and its metabolites. Here, we report that dietary supplementation with conjugated linoleic acid, a mixture of linoleic acid isomers, ameliorates CNS autoimmunity in a spontaneous mouse model of multiple sclerosis, accompanied by an attenuation of intestinal harrier dysfunction and inflammation as well as an increase in intestinal myeloid-derived sup pressor-like cells. Protective effects of dietary supplementation with conjugated linoleic acid were not abrogated upon microbiota eradication, indicating that the microbiome is dispensable for these conjugated linoleic acid-mediated effects. Instead, we observed a range of direct anti-inflammatory effects of conjugated linoleic acid on murine myeloid cells including an enhanced IL10 production and the capacity to suppress T-cell proliferation. Finally, in a human pilot study in patients with multiple sclerosis (n = 15 under first-line disease-modifying treatment), dietary conjugated linoleic acid-supplementation for 6 months significantly enhanced the anti-inflammatory profiles as well as functional signatures of circulating myeloid cells. Together, our results identify conjugated linoleic acid as a potent modulator of the gut-CNS axis by targeting myeloid cells in the intestine, which in turn control encephalitogenic T-cell responses.

Automated summary

The study demonstrates that conjugated linoleic acid can modulate gut-CNS axis by targeting myeloid cells in the intestine, which in turn control encephalitogenic T-cell responses. These anti-inflammatory effects are not affected by microbiome eradication and show significant improvements in patients with multiple sclerosis.