Stroke, a cerebro-vascular disease  presents a major global health problem, rated as the world's second-leading cause of death and the third most common cause of disability. Although in recent years there have been remarkable achievements in prevention, treatment, and recovery of post-stroke complications still, there is not a definite solution to overcome for this global problem.  Differential transcription of certain gene segments are implicated in the location of stroke, which imbalances the proteome. Protein IL-1β anticipated to be the main culprit for the epigenetic modifications. Link between faecal microbiota transplantation (FMT) and Stroke management has been tried in rat model which gave promising results. In the recent past, several studies have indicated the key role of the gut microbiota composition and its alterations in the pathophysiology of stroke similar to many other diseases. In the present review, the alteration of gut microbiota due to the disease as well as dysbiosis of the microbiota as a causal factor for the development of the disease is discussed. The results of FMT trials in animal models and few human trials are summarised. 

Stroke, a cerebrovascular disease  presents a major global health problem rated very high in terms of disability and death.  Ischaemic stroke and hemorrhagic stroke are the two types, and ischaemic stroke accounts for 85% of all strokes. Neuronal damage due to stroke induces  series of complex pathophysiological processes,           including       neuroinflammation,   excitotoxicity, oxidative stress, and apoptosis. Ischaemic stroke caused by sudden occlusion of cerebral blood vessels resulting in cerebral hypoperfusion and neuronal damage. If left untreated promptly, ischaemic stroke will lead to serious consequences [1].

Certain gene segments are transcribed differently there, after the stroke, which imbalances the proteome. These epigenetic modifications occur most frequently in the heart, where they can cause scarring and impair pumping function. [2] identified   that protein IL-1β is the main culprit for the epigenetic modifications which affect immunological memory after a stroke [2].

Although in recent years there have been remarkable achievements in prevention, treatment, and recovery of post-stroke complications till  now, however, there is not a definite solution to overcome for this global problem [3],[4]  in their systematic review to understand the link between Fecal microbiota transplantation  (FMT) and Stroke management. FMT  from healthy or ischemic donor to other ischemic recipient was found to  affect brain infarct volume and survival rate, neurological and behavioural outcomes, and inflammatory pathways. In the recent past, several studies have indicated the key role of the gut microbiota composition and its alterations in the pathophysiology of stroke [4,5]. 

Microbiota-Gut-Brain Axis

However, evidence suggests that bidirectional communication exists between the gut and its microbiota and the brain designated as the microbiota-gut-brain axis.  The initial dose of microbes from mother, multiply and the grown up human body contain in a range of 30 to 40 trillion in numbers. Among the many chemicals  they produce, some are beneficial to the host and others are harmful. Hundreds of neuro-chemicals produced by the gut microbes after the gut-brain axis is established regulate basic physiological processes as well as mental processes such as learning, memory and mood. In turn the dysbiosis and inflammation of the gut are responsible for anxiety and depression which are prevalent in society today [6].

Signalling between the brain and the gut occurs through both neuronal and non-neuronal mechanisms. The top-down signalling (brain→gut) from brain to gut wall is a direct communication via parasympathetic and sympathetic nerve fibers, or indirectly following stimulation of the enteric nervous system located in the submucosa and myenteric plexi of the gut wall. These neuronal signals influence gut motility, gut permeability, microbiota makeup, and resident immune cell activation.

Bottom-up signalling (gut→brain) is thought to occur through several different mechanisms. 1. The vagus nerve, composed of 80

Bottom-up signalling (gut→brain) is thought to occur through several different mechanisms. 1. The vagus nerve, composed of 80

The impact of dysbiosis of the gut microbiota as a causal factor for the prognosis of stroke  rely solely on studies conducted in laboratory animals and hardly be translated to the human disease state without human trials. In addition, dysbiosis or an unhealthy shift in the gut microbiota is likely not an alteration in one or a few bacterial species. The altered gut microbiome needs to be  viewed as an ecological community acting together to affect the host in a beneficial or detrimental manner.