Kefir Ameliorates Specific Physiological and Behavioural Impairments in a Mouse Model of Autism Spectrum Disorder

Abstract Autism spectrum disorders (ASD) is one of the most severe developmental disorders, affecting on average 1 in 150 children worldwide. There are limited treatment options for ASD symptoms and there is therefore a great need for more effective strategies to improve quality of life in ASD subjects. The gut microbiome has recently emerged as a therapeutic target in ASD. A novel modulator of the gut microbiome, the traditionally fermented milk drink kefir, has recently been shown to modulate the microbiota and decrease repetitive behaviour, one of the hallmarks of ASD. As such, we hypothesised that kefir could ameliorate the behavioural phenotype of ASD in the animal model of ASD; the BTBR T + Itpr3 tf /J mouse strain. Adult mice were administered either kefir (UK4) or milk control for 3 weeks as treatment lead-in, after which they were assessed for their behavioural phenotype using a battery of tests. In addition, we assessed systemic immunity by flow cytometry. We found that kefir decreased repetitive behaviour. Furthermore, kefir prolonged stress-induced increases in corticosterone 60 minutes post-stress, which was accompanied by an ameliorated innate immune response as measured by LY6C hi monocyte levels. Furthermore, kefir increased the levels of anti-inflammatory Treg cells in mesenteric lymph nodes. Altogether, our data show that kefir modulates peripheral immunity in an anti-inflammatory manner and can ameliorate specific ASD behavioural dysfunctions, indicating that kefir supplementation might prove a viable strategy in improving quality of life in ASD subjects.