Healthy Gut, Healthy Brain: The Gut Microbiome in Neurodegenerative Disorders.

The central nervous system (CNS) known to regulate the physiological conditions of human body, also itself gets dynamically regulated by both the physiological as well as pathological conditions of the body. These conditions get changed quite often, and often involve changes introduced into the gut microbiota which, as studies are revealing, directly modulate the CNS via a crosstalk. This cross-talk between the gut microbiota and CNS, i.e., the gut-brain axis (GBA), plays a major role in the pathogenesis of many neurodegenerative disorders such as Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS) and Huntington's disease (HD). We aim to discuss how gut microbiota, through GBA, regulate neurodegenerative disorders such as PD, AD, ALS, MS and HD. In this review, we have discussed the present understanding of the role played by the gut microbiota in neurodegenerative disorders and emphasized the probable therapeutic approaches being explored to treat them. In the first part, we introduce the GBA and its relevance, followed by the changes occurring in the GBA during neurodegenerative disorders and then further discuss its role in the pathogenesis of these diseases. Finally, we discuss its applications in possible therapeutics of these diseases and the current research improvements being made to better investigate this interaction. We concluded that alterations in the intestinal microbiota modulate various activities that could potentially lead to CNS disorders through interactions via the GBA.

Chandra S ，Alam MT ，Dey J ，Sasidharan BCP ，Ray U ，Srivastava AK ，Gandhi S ，Tripathi PP ... -  《-》

Gut-Brain Axis Deregulation and Its Possible Contribution to Neurodegenerative Disorders.

Villavicencio-Tejo F ，Olesen MA ，Navarro L ，Calisto N ，Iribarren C ，García K ，Corsini G ，Quintanilla RA ... -  《-》

Microbiota-Brain-Gut Axis and Neurodegenerative Diseases.

Quigley EMM 《-》

Unhealthy gut, unhealthy brain: The role of the intestinal microbiota in neurodegenerative diseases.

The number of bacterial cells living within the human body is approximately equal to, or greater than, the total number of human cells. This dynamic population of microorganisms, termed the human microbiota, resides mainly within the gastrointestinal tract. It is widely accepted that highly diverse and stable microbiota promote overall human health. Colonization of the gut with maladaptive and pathogenic microbiota, a state also known as dysbiosis, is associated with a variety of peripheral diseases ranging from type 2 diabetes mellitus to cardiovascular and inflammatory bowel disease. More recently, microbial dysbiosis has been associated with a number of brain pathologies, including autism spectrum disorder, Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), suggesting a direct or indirect communication between intestinal bacteria and the central nervous system (CNS). In this review, we illustrate two pathways implicated in the crosstalk between gut microbiota and CNS involving 1) the vagus nerve and 2) transmission of signaling molecules through the circulatory system and across the blood-brain barrier (BBB). We summarize the available evidence of the specific changes in the intestinal microbiota, as well as microorganism-induced modifications to intestinal and BBB permeability, which have been linked to several neurodegenerative disorders including ALS, AD, and PD. Even though each of these diseases arises from unique pathogenetic mechanisms, all are characterized, at least in part, by chronic neuroinflammation. We provide an interpretation for the substantial evidence that healthy intestinal microbiota have the ability to positively regulate the neuroimmune responses in the CNS. Even though the evidence is mainly associative, it has been suggested that bacterial dysbiosis could contribute to an adverse neuroinflammatory state leading to increased risk of neurodegenerative diseases. Thus, developing strategies for regulating and maintaining healthy intestinal microbiota could be a valid approach for lowering individual risk and prevalence of neurodegenerative diseases.

Spielman LJ ，Gibson DL ，Klegeris A 《-》

Understanding the Gut-Brain Axis and Its Therapeutic Implications for Neurodegenerative Disorders.

Zheng Y ，Bonfili L ，Wei T ，Eleuteri AM ... -  《Nutrients》