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Microbiota from Alzheimer’s patients induce deficits in cognition and hippocampal neurogenesis
Alzheimer’s disease is a multifaceted neurological condition that impairs mental and cognitive abilities. Recent studies pointed to distinct changes in the gut microbiome makeup of Alzheimer’s patients and animal models, positioning the gut microbiota as a significant susceptibility factor in Alzheimer’s disease. It is unclear, therefore, if changes in the gut microbiota are responsible for the emergence of Alzheimer’s symptoms. Grabrucker et al. (2023) transplanted fecal microbiota from Alzheimer’s patients and age-matched healthy controls into microbiota-depleted young adult rats in order to better understand the role of the gut microbiota of Alzheimer’s patients in host physiology and behavior. The authors noted that adult hippocampus neurogenesis —a crucial process for several memory and mood functions—was impaired in behaviors associated with transplants from Alzheimer’s patients. Notably, among donor patients, the degree of impairments was linked with clinical cognitive scores. There were also noticeable variations in the rat hippocampus and caecal metabolomes. Since the circulatory systemic environment modulates hippocampus neurogenesis, which cannot be detected in living individuals, the authors evaluated the effect of the Alzheimer’s systemic environment on proxy neurogenesis readouts. In vitro, serum from Alzheimer’s patients reduced neurogenesis in human cells and was linked to critical microbial genera and cognitive scores. The authors demonstrate through their findings for the first time that gut microbiota can transmit Alzheimer’s symptoms to a young, healthy organism, supporting the hypothesis that gut microbiota causes Alzheimer’s disease, in addition to highlighting hippocampal neurogenesis as a central cellular process that converges to regulate both gut-mediated and systemic circulatory factors in Alzheimer’s disease. [NPID: Alzheimer’s disease, fecal microbiota transplantation, memory, adult hippocampal neurogenesis]
Year: 2023
