Acute disruption of bacterial populations in the gut after stroke could have a detrimental effect on recovery, according to new research.
The role that our microbiome – the microbial environment found within our bodies – has in protecting us from infection and disease is still gathering momentum in various branches of science and medicine.
In critical care, for example, patients admitted to the intensive care unit for conditions such as sepsis are given large numbers of antibiotics, which are known to cause massive collateral damage to the otherwise healthy flora of microbiota in the gut.1 Crucially, restoration of the microbiota after antibiotic treatment using methods such as probiotics or even faecal microbiota transfers from healthy patients have been successful in protecting against subsequent infections.1
As research develops, initiatives such as the Human Microbiome Project2 have spent hundreds of millions of dollars characterising the bacterial makeup of large groups of people, hoping to drive forward what we know about the microbiome and its impact on health.
In new research, presented at the 2019 International Stroke Conference in Hawaii, Brichacek et al. explored the theory that gut microbiota plays an important role in post-stroke morbidity and mortality.3
In this study, mice with induced ischemic stroke were compared to controls at 3, 14 and 28 days after the stroke. The researchers found that the stroke group had significant decreases in the beneficial bacteria Bifidobacteriaceae and Lactobacillaceae, as well as significant increases in harmful bacteria Helicobacteraceae and Enterobacteriaceae.3 Structural changes to the intestinal tissue of the stroke mice were also apparent, with chronic inflammation leading to likely impairment of nutrient absorption in the gut.
In addition, they observed a change in Firmicutes-to-Bacteroidetes bacterial ratio in the stroke group, which is known to heighten the risk of developing obesity, diabetes and abnormal inflammation. It follows, therefore, that the gut has an important role to play in the subsequent morbidity that stroke sufferers may entail.
All-told, as the authors note, a shift in balance of these bacterial populations could have profound implications on post-stroke recovery. “Chronic change 28 days after [a] stroke that is associated with this increase in some of the negative bacteria means that this could have negative effects on brain function and behaviour,” noted co-author Candice M Brown, an associate professor at the West Virginia University School of Medicine, USA.
“If it ends up being that the gut has an influence on the repair of the brain, maybe our stroke treatments shouldn’t just be focused on what we can do for the brain. Maybe we need to think about what [we can] do for the gut.”