Long term changes to the intestinal microbiome seen after stroke

New study finds changes in gut structure and microbiome long after a stroke, which likely contributes to gastrointestinal complications. The researchers (McCulloch lab and colleagues) also found changes in gut antibodies and how they interact with bacteria, potentially causing ongoing microbial imbalance. These findings offer new potential targets that could improve gut health and long-term recovery after stroke.

The communication pathway between the brain and the gut, known as the gut-brain axis, plays a crucial role in health and disease. Research has shown that strokes can significantly disrupt this connection, leading to a range of gastrointestinal (GI) complications including issues with swallowing, constipation, GI bleeds and changes to the gut microbiome. Such GI issues are not just symptomatic; they also correlate with poorer recovery outcomes, exacerbation of brain injuries, and an increased risk of subsequent strokes.

In patients, GI dysfunction can persist throughout stroke recovery. However, current research mainly focuses on the immediate effects post-stroke, leaving significant gaps in understanding the long-term resolution or progression of GI dysfunction.

In this study, IRR’s McCulloch lab, in collaboration with colleagues at IRR and the University of Glasgow, used a mouse model of stroke to examine changes to intestinal structure and functions (production of mucus, transit time of food); the gut microbiome and the intestinal immune system. They explored how the gut changes in response to stroke, and which of these changes persist long-term.

Our findings offer new potential targets for interventions aimed at improving gut health and overall outcomes throughout the stroke recovery process.

The researchers found that stroke-induced changes in gut structure persist long after the initial event. These long-term structural alterations may influence nutrient absorption in survivors well into recovery.

They also showed, for the first time, that changes in the gut microbiome remain during the late stages of stroke recovery. Not only this, but the early and late microbiome profiles were compositionally distinct. Initial microbiome changes may stem from early disruptions such as a reduced mucus barrier (which acts to protect the colon wall from bacteria, lubricate stool movement and regulate immune signals) and prolonged intestinal transit times, similar to constipation.

Two images showing the inside lumen of the intestine for comparison — Cross section of a healthy colon (left) and post-stroke colon (right). There is a reduced mucus barrier seen early on post-stroke, that may contribute to early gut microbiome changes, and shortened crypts, the structures responsible for the uptake of water and nutrients.

Additional changes emerged only during later recovery, including changes in the types of gut antibodies and how they interact with bacterial communities. These interactions may contribute to maintaining microbial imbalance. To determine whether such antibody - microbiome interactions happen in human stroke recovery, longitudinal patient studies are essential.

The researchers now aim to prevent or modify these antibody-related changes, with the goal of improving gastrointestinal health and overall recovery outcomes after stroke.

Related links

Tags