The Roles of the Microbiome in Alzheimer’s Disease

The gut and the brain are in constant communication in a complex network known as the brain-gut axis. A growing body of research has found links between the brain-gut axis and Alzheimer’s Disease (AD). In this review, we will explore how the mammalian microbiome affects neuroinflammation and increases the permeability of the blood brain barrier in the context of AD. Research shows that the microbiome is associated with neuroinflammation in AD, which is presumably caused by the secretion of cytokines from specialized cells of the brain - microglia and astrocytes. On the other hand, metabolic diseases, caused by microbiota dysbiosis, can increase the permeability of the blood brain barrier. In addition, its higher permeability can allow blood plasma components to enter brain tissue and further develop AD pathology. Findings of the current research have tremendous therapeutic implications. Researchers have speculated whether the therapeutic modification of gut microbiota, through the use of antibiotics and probiotics, may show improvement in AD patients. Our understanding of the pathways and mechanisms involved in the brain-gut axis and AD is still very limited and requires further research before clinical and therapeutic interventions can occur.