Interrelationships Among Gut Microbiota and Host: Paradigms, Role in Neurodegenerative Diseases and Future Prospects

Advances in the knowledge of the microbiota and concepts related to it have triggered a wake-up call in biomedicine. The development in various scientific areas has enabled a better and broader approach to everything concerning the set of families of microorganisms that coexist with an individual and are able to function as one or more organs in its body. Among the aforementioned scientific areas, those worth mentioning are the advances/progress in biotechnological resources and, in particular, molecular biology and related areas. This has given rise to the era of "omics", marking a turning point in the understanding of numerous physiologic and pathophysiologic processes of the organism. The current theory is that the microbiota and the host maintain an intimate relationship that is of a markedly bilateral nature. This continuous feedback has different connotations between one individual and another, but also within the same individual throughout its life span, which is determined by its own conditioning factors (such as its genetic profile), and environmental ones (mainly diet and lifestyles). Both elements (microbiota and host) coexist harmoniously, maintaining a balance, which can be altered and give rise to different morbid entities. Among these is its relation to chronic processes, and especially those of an autoimmune origin. Such may be neurological diseases situations and, specifically, those of a neurodegenerative nature. In disorders such as multiple sclerosis, amyotrophic lateral sclerosis, Huntington's chorea and Alzheimer's disease, among others, it has been found that a disharmonic coexistence between microbiota and host may have implications in their etiology and pathogenesis. A better understanding of those implications has led to the development of actions on the gut microbiota as a target to slow down the advancement or establishment of neurodegeneration.

In this scenario, several treatment strategies have emerged, such as probiotic food intake and stool transplantation. Their real potentialities remain to be elucidated, although current scientific evidence infers that the development of those therapeutic approaches could offer a ray of hope in the prospects of tackling neurodegenerative diseases.