Changes in gut microbiota and cytokines following laparoscopic sleeve gastrectomy are associated with cognitive function improvement

PURPOSE: Variations of cytokines and gut microbiota diversity with improved cognitive function in patients with obesity following bariatric surgery were poorly understood. The aim of this study was to testify the relationship among gut microbiota, cytokines and cognitive function in patients with obesity before and after laparoscopic sleeve gastrectomy (LSG). METHODS: Forty patients were enrolled in this study. Demographics, and serum and stool specimens were collected from all patients before and 3 months after LSG. The Montreal Cognitive Assessment (MoCA) scale, as well as assessment of immediate and delayed memory were used to evaluate self-perceived cognitive improvement after LSG. RESULTS: LSG resulted in significant weight loss and improvement in cognitive functions, as measured by questionnaires. Bariatric surgery tended to increase gut microbiota relative abundance and diversity. The intestinal flora increased in the proportion of Bacteroidetes and Fusobacteria phyla, and decreased in the proportion of Firmicutes, Proteobacteria, and Actinobacteria phyla after LSG. Plasma IL-1β and TNF-α levels were significantly decreased following LSG, while IL-4 was significantly increased. MoCA test scores were significant correlated with IL-4, TNF-α and IL-1β. In addition, Firmicutes had a positive correlation with TNF-α, while Fuscobacteria had a negative correlation with IL-1β. Bacteroidetes was negatively correlated with IL-4. CONCLUSION: Changes in gut microbiota were positive relationship with cognitive function improvement following LSG. Inflammation cytokines maybe played as a mediator between gut microbiota and cognitive function through gut-microbiota-brain axis.