Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theory
Controversies surrounding the validity of the toxic proteinopathy theory of Alzheimer’s disease have led the scientific community to seek alternative theories in the pathogenesis of neurodegenerative disorders (ND). Recent studies have provided evidence of a microbiome in the central nervous system....
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-10-01
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| Series: | Frontiers in Aging Neuroscience |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fnagi.2023.1240945/full |
| _version_ | 1797656039551664128 |
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| author | Tarek Ziad Arabi Aliyah Abdulmohsen Alabdulqader Belal Nedal Sabbah Abderrahman Ouban Abderrahman Ouban |
| author_facet | Tarek Ziad Arabi Aliyah Abdulmohsen Alabdulqader Belal Nedal Sabbah Abderrahman Ouban Abderrahman Ouban |
| author_sort | Tarek Ziad Arabi |
| collection | DOAJ |
| description | Controversies surrounding the validity of the toxic proteinopathy theory of Alzheimer’s disease have led the scientific community to seek alternative theories in the pathogenesis of neurodegenerative disorders (ND). Recent studies have provided evidence of a microbiome in the central nervous system. Some have hypothesized that brain-inhabiting organisms induce chronic neuroinflammation, leading to the development of a spectrum of NDs. Bacteria such as Chlamydia pneumoniae, Helicobacter pylori, and Cutibacterium acnes have been found to inhabit the brains of ND patients. Furthermore, several fungi, including Candida and Malassezia species, have been identified in the central nervous system of these patients. However, there remains several limitations to the brain microbiome hypothesis. Varying results across the literature, concerns regarding sample contamination, and the presence of exogenous deoxyribonucleic acids have led to doubts about the hypothesis. These results provide valuable insight into the pathogenesis of NDs. Herein, we provide a review of the evidence for and against the brain microbiome theory and describe the difficulties facing the hypothesis. Additionally, we define possible mechanisms of bacterial invasion of the brain and organism-related neurodegeneration in NDs and the potential therapeutic premises of this theory. |
| first_indexed | 2024-03-11T17:23:29Z |
| format | Article |
| id | doaj.art-438b6ac1676947deaf65d8f56d228350 |
| institution | Directory Open Access Journal |
| issn | 1663-4365 |
| language | English |
| last_indexed | 2024-03-11T17:23:29Z |
| publishDate | 2023-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Aging Neuroscience |
| spelling | doaj.art-438b6ac1676947deaf65d8f56d2283502023-10-19T07:45:05ZengFrontiers Media S.A.Frontiers in Aging Neuroscience1663-43652023-10-011510.3389/fnagi.2023.12409451240945Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theoryTarek Ziad Arabi0Aliyah Abdulmohsen Alabdulqader1Belal Nedal Sabbah2Abderrahman Ouban3Abderrahman Ouban4College of Medicine, Alfaisal University, Riyadh, Saudi ArabiaCollege of Medicine, Alfaisal University, Riyadh, Saudi ArabiaCollege of Medicine, Alfaisal University, Riyadh, Saudi ArabiaCollege of Medicine, Alfaisal University, Riyadh, Saudi ArabiaDepartment of Pathology, College of Medicine, Alfaisal University, Riyadh, Saudi ArabiaControversies surrounding the validity of the toxic proteinopathy theory of Alzheimer’s disease have led the scientific community to seek alternative theories in the pathogenesis of neurodegenerative disorders (ND). Recent studies have provided evidence of a microbiome in the central nervous system. Some have hypothesized that brain-inhabiting organisms induce chronic neuroinflammation, leading to the development of a spectrum of NDs. Bacteria such as Chlamydia pneumoniae, Helicobacter pylori, and Cutibacterium acnes have been found to inhabit the brains of ND patients. Furthermore, several fungi, including Candida and Malassezia species, have been identified in the central nervous system of these patients. However, there remains several limitations to the brain microbiome hypothesis. Varying results across the literature, concerns regarding sample contamination, and the presence of exogenous deoxyribonucleic acids have led to doubts about the hypothesis. These results provide valuable insight into the pathogenesis of NDs. Herein, we provide a review of the evidence for and against the brain microbiome theory and describe the difficulties facing the hypothesis. Additionally, we define possible mechanisms of bacterial invasion of the brain and organism-related neurodegeneration in NDs and the potential therapeutic premises of this theory.https://www.frontiersin.org/articles/10.3389/fnagi.2023.1240945/fullneurodegenerative diseasebrain microbiomeAlzheimer’s diseaseParkinson’s diseasebacteriabrain-inhabiting bacteria |
| spellingShingle | Tarek Ziad Arabi Aliyah Abdulmohsen Alabdulqader Belal Nedal Sabbah Abderrahman Ouban Abderrahman Ouban Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theory Frontiers in Aging Neuroscience neurodegenerative disease brain microbiome Alzheimer’s disease Parkinson’s disease bacteria brain-inhabiting bacteria |
| title | Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theory |
| title_full | Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theory |
| title_fullStr | Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theory |
| title_full_unstemmed | Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theory |
| title_short | Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theory |
| title_sort | brain inhabiting bacteria and neurodegenerative diseases the brain microbiome theory |
| topic | neurodegenerative disease brain microbiome Alzheimer’s disease Parkinson’s disease bacteria brain-inhabiting bacteria |
| url | https://www.frontiersin.org/articles/10.3389/fnagi.2023.1240945/full |
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