Gut microbial dysbiosis is correlated with stroke severity markers in aged rats following stroke

An imbalanced gut microbial community, or dysbiosis, has been shown to occur following stroke. It is possible that this dysbiosis negatively impacts stroke recovery and rehabilitation. Species level resolution measurements of the gut microbiome following stroke are needed to develop and test precision interventions such as probiotic or fecal microbiota transplant therapies that target the gut microbiome following stroke. Thirty-nine aged male and female rats underwent middle cerebral artery occlusion. Fecal samples were collected before stroke and three days post stroke to measure gut microbiome. Dysbiosis was demonstrated by an increase in pathogenic bacteria such as Butyricimonas virosa (15.52 fold change, p<0.0001), Bacteroides vulgatus (7.36 fold change, p<0.0001), and Escherichia coli (47.67 fold change, p<0.0001). These bacteria were positively associated with infarct and edema size and with the inflammatory markers Ccl19, Ccl24, IL17a, IL3, and complement C5; they were negatively correlated with CBF. Conversely, beneficial bacteria such as Ruminococcus flavefaciens (0.14 fold change, p<0.0001), Akkermansia muciniphila (0.78 fold change, p<0.0001), and Lactobacillus murinus (0.40 fold change, p<0.0001) were decreased following stroke and associated with all the previous parameters in the opposite direction of the pathogenic species. There were not significant microbiome differences between the sexes.