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Hu Q, Wang S, Zhang W, Qu J, Liu GH. Unraveling brain aging through the lens of oral microbiota. Neural Regen Res 2025; 20:1930-1943. [PMID: 38993126 DOI: 10.4103/nrr.nrr-d-23-01761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 05/31/2024] [Indexed: 07/13/2024] Open
Abstract
The oral cavity is a complex physiological community encompassing a wide range of microorganisms. Dysbiosis of oral microbiota can lead to various oral infectious diseases, such as periodontitis and tooth decay, and even affect systemic health, including brain aging and neurodegenerative diseases. Recent studies have highlighted how oral microbes might be involved in brain aging and neurodegeneration, indicating potential avenues for intervention strategies. In this review, we summarize clinical evidence demonstrating a link between oral microbes/oral infectious diseases and brain aging/neurodegenerative diseases, and dissect potential mechanisms by which oral microbes contribute to brain aging and neurodegeneration. We also highlight advances in therapeutic development grounded in the realm of oral microbes, with the goal of advancing brain health and promoting healthy aging.
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Affiliation(s)
- Qinchao Hu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Si Wang
- Advanced Innovation Center for Human Brain Protection and National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China
- Aging Translational Medicine Center, International Center for Aging and Cancer, Beijing Municipal Geriatric Medical Research Center, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Weiqi Zhang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Aging Biomarker Consortium, Beijing, China
| | - Jing Qu
- University of Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Aging Biomarker Consortium, Beijing, China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
| | - Guang-Hui Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Advanced Innovation Center for Human Brain Protection and National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China
- Aging Translational Medicine Center, International Center for Aging and Cancer, Beijing Municipal Geriatric Medical Research Center, Xuanwu Hospital, Capital Medical University, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Aging Biomarker Consortium, Beijing, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
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2
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Gancz NN, Querdasi FR, Chu KA, Towner E, Taylor E, Callaghan BL. Characteristics of the oral microbiome in youth exposed to caregiving adversity. Brain Behav Immun Health 2024; 41:100850. [PMID: 39280088 PMCID: PMC11401114 DOI: 10.1016/j.bbih.2024.100850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2024] [Accepted: 08/24/2024] [Indexed: 09/18/2024] Open
Abstract
Caregiving adversity (CA) exposure is robustly linked to increased risk for poor oral, physical, and mental health outcomes. Increasingly, the gut microbiome has garnered interest as a contributor to risk for and resilience to such health outcomes in CA-exposed individuals. Though often overlooked, the oral microbiome of CA-exposed individuals may be just as important a contributor to health outcomes as the gut microbiome. Indeed, outside the context of CA, the oral microbiome is well-documented as a regulator of both oral and systemic health, and preliminary data suggest its association with mental health. However, research examining the association between CA and the oral microbiome is extremely sparse, especially in childhood, when the community composition of such organisms is still stabilizing. To address that sparsity, in the current study, we examined composition and differential abundance metrics of the oral microbiome in 152 youth aged 6-16 years, who had either been exposed to significant caregiving adversity (significant separation from or maltreatment by a caregiver; N = 66, CA) or who had always remained with their biological/birth families (N = 86, Comparison). We identified a significant negative association between hair cortisol and oral microbiome richness in the Comparison group that was significantly blunted in the CA group. Additionally, youth in the CA group had altered oral microbiome composition and elevated abundance of potentially pathogenic bacteria relative to youth in the Comparison group. Questionnaire measures of fatigue, somatic complaints, and internalizing symptoms had limited associations with oral microbiome features that were altered in CA. Although we found differences in the oral microbiomes of CA-exposed youth, further research is required to elucidate the implications of those differences for health and well-being.
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Affiliation(s)
- Naomi N Gancz
- University of California, Los Angeles, 502 Portola Plaza, Los Angeles, CA, 90095, United States
| | - Francesca R Querdasi
- University of California, Los Angeles, 502 Portola Plaza, Los Angeles, CA, 90095, United States
| | - Kristen A Chu
- University of California, Los Angeles, 502 Portola Plaza, Los Angeles, CA, 90095, United States
| | - Emily Towner
- University of California, Los Angeles, 502 Portola Plaza, Los Angeles, CA, 90095, United States
| | - Eason Taylor
- University of California, Los Angeles, 502 Portola Plaza, Los Angeles, CA, 90095, United States
| | - Bridget L Callaghan
- University of California, Los Angeles, 502 Portola Plaza, Los Angeles, CA, 90095, United States
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3
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Tessarin GWL, Toro LF, Pereira RF, Dos Santos RM, Azevedo RG. Peri-implantitis with a potential axis to brain inflammation: an inferential review. Odontology 2024; 112:1033-1046. [PMID: 38630323 DOI: 10.1007/s10266-024-00936-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 03/26/2024] [Indexed: 09/21/2024]
Abstract
Peri-implantitis (PI) is a chronic, inflammatory, and infectious disease which affects dental implants and has certain similarities to periodontitis (PD). Evidence has shown that PD may be related to several types of systemic disorders, such as diabetes and insulin resistance, cardiovascular diseases, respiratory tract infections, adverse pregnancy outcomes, and neurological disorders. Furthermore, some types of bacteria in PD can also be found in PI, leading to certain similarities in the immunoinflammatory responses in the host. This review aims to discuss the possible connection between PI and neuroinflammation, using information based on studies about periodontal disorders, a topic whose connection with systemic alterations has been gaining the interest of the scientific community. Literature concerning PI, PD, and systemic disorders, such as neuroinflammation, brain inflammation, and neurological disorder, was searched in the PubMed database using different keyword combinations. All studies found were included in this narrative review. No filters were used. Eligible studies were analyzed and reviewed carefully. This study found similarities between PI and PD development, maintenance, and in the bacterial agents located around the teeth (periodontitis) or dental implants (peri-implantitis). Through the cardiovascular system, these pathologies may also affect blood-brain barrier permeability. Furthermore, scientific evidence has suggested that microorganisms from PI (as in PD) can be recognized by trigeminal fiber endings and start inflammatory responses into the trigeminal ganglion. In addition, bacteria can traverse from the mouth to the brain through the lymphatic system. Consequently, the immune system increases inflammatory mediators in the brain, affecting the homeostasis of the nervous tissue and vice-versa. Based on the interrelation of microbiological, inflammatory, and immunological findings between PD and PI, it is possible to infer that immunoinflammatory changes observed in PD can imply systemic changes in PI. This, as discussed, could lead to the development or intensification of neuroinflammatory changes, contributing to neurodegenerative diseases.
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Affiliation(s)
- Gestter Willian Lattari Tessarin
- University Center in the North of São Paulo (UNORTE), São José Do Rio Preto, SP, 15020-040, Brazil.
- Department of Basic Sciences, School of Dentistry, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil.
| | - Luan Felipe Toro
- Department of Basic Sciences, School of Dentistry, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil
- Marilia Medical School (FAMEMA), Marília, São Paulo, Brazil
| | - Renato Felipe Pereira
- Union of Colleges of the Great Lakes (UNILAGO), São José Do Rio Preto, São Paulo, Brazil
| | - Rodrigo Martins Dos Santos
- Department of Basic Sciences, School of Dentistry, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil
| | - Renato Gomes Azevedo
- University Center in the North of São Paulo (UNORTE), São José Do Rio Preto, SP, 15020-040, Brazil
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4
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Cerajewska TL, Davies M, Allen-Birt SJ, Swirski M, Coulthard EJ, West NX. A feasibility study to recruit, retain and treat periodontitis in volunteers with mild dementia, whilst monitoring their cognition. J Dent 2024:105355. [PMID: 39293537 DOI: 10.1016/j.jdent.2024.105355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2024] [Revised: 09/12/2024] [Accepted: 09/13/2024] [Indexed: 09/20/2024] Open
Abstract
OBJECTIVES Dementia patients are challenging to manage dentally. This study determined whether individuals with mild dementia and periodontitis, could be recruited, retained and demonstrate sustained oral health improvements over 2 years following personalised professional periodontitis treatment. The feasibility of same visit cognition measurements was assessed. METHODS A non-randomised study in individuals with mild dementia, capacity to consent, periodontitis and ≥6 teeth. Following enrolment and dental/cognitive assessments, personalised periodontal treatment, followed by 3-monthly supportive periodontal care was performed. Cognitive and periodontal assessments were undertaken at 6, 12, 24-months. Participants and project-partners fed back on homecare regimens. RESULTS 18 participants were recruited, 15 completed 12- & 8 completed 24-months, 1 participant failed to attend one appointment, and early study termination due to COVID19. From baseline to 12-months mean percentage bleeding sites, Turesky plaque score ≥2 and periodontal pockets ≥4mm decreased significantly (34.4 vs 14.75, p<0.01; 78.49 vs 57.5, p<0.01; 18.38 vs 5.14, p<0.001). Significant change from baseline was retained at 24-months for mean percentage periodontal pockets ≥4mm (14.47 vs 4.29, p<0.05; n=8). Cognition declined significantly to 12-months (mean ACEIII 71.47 vs 65.40, p<0.05), but not between 12- and 24-months (67.5 vs 65.38, n=8). Most reported home-care regimen as easy/OK to follow. CONCLUSIONS Mild dementia participants with periodontitis can be recruited, retained in a 24-month study and periodontally treated with personalised professional and at-home care regimens. Cognitive assessments can be performed at the same treatment visit. This demonstrates sustained engagement and supports oral health compliance can be successful in challenging cohorts.
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Affiliation(s)
- Tanya L Cerajewska
- Periodontology, Clinical Trials Unit, Bristol Dental School, University of Bristol, UK.
| | - Maria Davies
- Periodontology, Clinical Trials Unit, Bristol Dental School, University of Bristol, UK.
| | | | - Marta Swirski
- Clinical Neurosciences, Bristol Medical School, Bristol, UK.
| | | | - Nicola X West
- Periodontology, Clinical Trials Unit, Bristol Dental School, University of Bristol, UK.
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Butler CA, Ciccotosto GD, Rygh N, Bijlsma E, Dashper SG, Brown AC. Bacterial Membrane Vesicles: The Missing Link Between Bacterial Infection and Alzheimer Disease. J Infect Dis 2024; 230:S87-S94. [PMID: 39255395 PMCID: PMC11385588 DOI: 10.1093/infdis/jiae228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/28/2024] [Indexed: 09/12/2024] Open
Abstract
Periodontitis is a common chronic inflammatory disease, affecting approximately 19% of the global adult population. A relationship between periodontal disease and Alzheimer disease has long been recognized, and recent evidence has been uncovered to link these 2 diseases mechanistically. Periodontitis is caused by dysbiosis in the subgingival plaque microbiome, with a pronounced shift in the oral microbiota from one consisting primarily of Gram-positive aerobic bacteria to one predominated by Gram-negative anaerobes, such as Porphyromonas gingivalis. A common phenomenon shared by all bacteria is the release of membrane vesicles to facilitate biomolecule delivery across long distances. In particular, the vesicles released by P gingivalis and other oral pathogens have been found to transport bacterial components across the blood-brain barrier, initiating the physiologic changes involved in Alzheimer disease. In this review, we summarize recent data that support the relationship between vesicles secreted by periodontal pathogens to Alzheimer disease pathology.
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Affiliation(s)
| | | | - Nathaniel Rygh
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania, USA
| | - Elly Bijlsma
- Melbourne Dental School, The University of Melbourne, Australia
| | | | - Angela C Brown
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania, USA
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Chen L, Li X, Liu J, Hou Z, Wei Y, Chen M, Wang B, Cao H, Qiu R, Zhang Y, Ji X, Zhang P, Xue M, Qiu L, Wang L, Li H. Distinctive subgingival microbial signatures in older adults with different levels of cognitive function. J Clin Periodontol 2024; 51:1066-1080. [PMID: 38769711 DOI: 10.1111/jcpe.13997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/22/2024]
Abstract
AIM To examine association between subgingival microbial signatures and levels of cognitive impairment in older adults. MATERIALS AND METHODS We analysed subgingival plaque samples and 16S ribosomal RNA sequences for microbiota among 165 participants (normal controls [NCs]: 40, subjective cognitive decline [SCD]: 40, mild cognitive impairment [MCI]: 49 and dementia: 36). RESULTS The bacterial richness was lower among individuals with worse cognitive function, and subgingival microbial communities differed significantly among the four groups. Declining cognitive function was associated with decreasing relative abundance of genera Capnocytophaga, Saccharibacteria_genera_incertae_sedis, Lautropia and Granulicatella, and increasing abundance of genus Porphyromonas. Moreover, there were differentially abundant genera among the groups. Random forest model based on subgingival microbiota could distinguish between cognitive impairment and NC (AUC = 0.933, 95% confidence interval 0.873-0.992). Significant correlations were observed between oral microbiota and sex, Montreal Cognitive Assessment (MoCA) score and Mini-Mental State Examination score. Partial correlation analysis showed that Leptotrichia and Burkholderia were closely negatively associated with the MoCA score after adjusting for multiple covariates. Gene function was not significantly different between SCD and NC groups, whereas three homozygous genes were altered in MCI patients and two in dementia patients. CONCLUSIONS This is the first study to demonstrate an association between the composition, function and metabolic pathways of subgingival microbiota and different levels of cognitive function among older individuals. Future cohort studies should assess its diagnostic usefulness for cognitive impairment.
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Affiliation(s)
- Lili Chen
- Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, China
- Department of Nursing, Fujian Provincial Hospital, Fuzhou, China
| | - Xiuli Li
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Jinxiu Liu
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Zhaoyi Hou
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Yongbao Wei
- Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, China
| | - Mingfeng Chen
- Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, China
| | - Bixia Wang
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Huizhen Cao
- Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, China
| | - Rongyan Qiu
- Department of Surgery, Fujian Provincial Governmental Hospital, Fuzhou, China
| | - Yuping Zhang
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Xinli Ji
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Ping Zhang
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Mianxiang Xue
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Linlin Qiu
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Linlin Wang
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Hong Li
- The School of Nursing, Fujian Medical University, Fuzhou, China
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7
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Singhrao SK, Consoli C, Dennison SR, Kanagasingam S, Welbury R. Porphyromonas gingivalis LPS and Actinomyces naeslundii Conditioned Medium Enhance the Release of a Low Molecular Weight, Transcriptionally Active, Fragment of Glycogen Synthase-3 Kinase in IMR-32 Cell Line. J Alzheimers Dis Rep 2024; 8:1055-1067. [PMID: 39114545 PMCID: PMC11305843 DOI: 10.3233/adr-240066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 06/19/2024] [Indexed: 08/10/2024] Open
Abstract
Background Glycogen synthase-3 kinase (GSK3) is one of the major contributors of tau hyperphosphorylation linked to neurofibrillary tangles in Alzheimer's disease (AD). Objective To determine a mechanism of GSK-3β activation by two periodontal bacteria consistently confirmed in AD autopsied brains. Methods Porphyromonas gingivalis FDC381 and Actinomyces naeslundii ATCC10301 conditioned media were collected. IMR-32 cells were challenged for 48 h with the conditioned media alongside P. gingivalis (ATCC33277) ultrapurified lipopolysaccharide (LPS) designated Pg.LPS under established cell culture conditions either alone or combined. Gene expression and protein analyses for GSK-3β were carried out. Results qPCR demonstrated that GSK-3β gene was overexpressed in IMR-32 cells treated with Pg.LPS with a 2.09-fold change (p = 0.0005), while A. naeslundii treated cells demonstrated 1.41-fold change (p = 0.004). Western blotting of the cells challenged with Pg.LPS (p = 0.01) and A. naeslundii conditioned medium (p = 0.001) demonstrated the 37 kDa band for each treatment with variable intensity across the medium control. Immunohistochemistry with the GSK-3β of the IMR-32 cells challenged with Pg.LPS and A. naeslundii alone demonstrated cytoplasmic and nuclear localization. Conclusions Exposure to various bacterial factors upregulated the gene expression of GSK-3β. Western blotting for GSK-3β confirmed the presence of the cleaved fragment by Pg.LPS (37 kDa band p = 0.01) and A. naeslundii conditioned medium (37 kDa band p = 0.001). Immunostaining demonstrated both cytoplasmic and nuclear localization of GSK-3β. Therefore, Pg.LPS and an unknown factor from the A. naeslundii conditioned medium mediated GSK-3β activation via its transcriptionally active, cleaved, fragment. These virulence factors in the body appear to be detrimental to brain health.
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Affiliation(s)
- Sim K. Singhrao
- School of Medicine and Dentistry, University of Central Lancashire, Preston, UK
| | - Claudia Consoli
- Central Biotechnology Services, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
| | - Sarah R. Dennison
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | | | - Richard Welbury
- School of Medicine and Dentistry, University of Central Lancashire, Preston, UK
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Yamada C, Ho A, Garcia C, Oblak AL, Bissel S, Porosencova T, Porosencov E, Uncuta D, Ngala B, Shepilov D, Skibo G, Mascarenhas AK, Akkaoui J, Lakshmana MK, Sankar U, Nichols F, Lamb BT, Groppa S, Movila A. Dementia exacerbates periodontal bone loss in females. J Periodontal Res 2024; 59:512-520. [PMID: 38243688 DOI: 10.1111/jre.13227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 01/21/2024]
Abstract
BACKGROUND Periodontitis is a chronic inflammatory disease defined by the pathologic loss of the periodontal ligament and alveolar bone in relation to aging. Although clinical cohort studies reported that periodontitis is significantly elevated in males compared to females, emerging evidence indicates that females with dementia are at a greater risk for periodontitis and decreased alveolar bone. OBJECTIVE This study aimed to evaluate whether dementia is a potential sex-dependent risk factor for periodontal bone loss using an experimental model of periodontitis induced in the triple transgenic (3x-Tg) dementia-like mice and clinical samples collected from senior 65 plus age patients with diagnosed dementia. MATERIALS AND METHODS We induced periodontitis in dementia-like triple-transgenic (3x-Tg) male and female mice and age-matched wild-type (WT) control mice by ligature placement. Then, alveolar bone loss and osteoclast activity were evaluated using micro-CT and in situ imaging assays. In addition, we performed dental examinations on patients with diagnosed dementia. Finally, dementia-associated Aβ42 and p-Tau (T181) and osteoclastogenic receptor activator of nuclear factor kappa-Β ligand (RANKL) in gingival crevicular fluid (GCF) collected from mice and clinical samples were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS Alveolar bone loss and in situ osteoclast activity were significantly elevated in periodontal lesions of 3x-Tg females but not males, compared to wild-type control mice. In addition, we also observed that the probing pocket depth (PPD) was also significantly elevated in female patients with dementia. Using ELISA assay, we observed that females had elevated levels of osteoclastogenic RANKL and dementia-associated Aβ42 and p-Tau (T181) in the GCF collected from experimental periodontitis lesions and clinical samples. CONCLUSION Altogether, we demonstrate that females with dementia have an increased risk for periodontal bone loss compared to males.
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Affiliation(s)
- Chiaki Yamada
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, Indiana, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Anny Ho
- Institute of Neuro-immune Medicine, Nova Southeastern University, Ft. Lauderdale, Florida, USA
| | - Christopher Garcia
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Adrian L Oblak
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Stephanie Bissel
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Tatiana Porosencova
- Faculty of Dentistry, "Nicolae Testemițanu" State University of Medicine and Pharmacy, Chisinau, Moldova
| | - Egor Porosencov
- Faculty of Dentistry, "Nicolae Testemițanu" State University of Medicine and Pharmacy, Chisinau, Moldova
| | - Diana Uncuta
- Faculty of Dentistry, "Nicolae Testemițanu" State University of Medicine and Pharmacy, Chisinau, Moldova
| | - Bidii Ngala
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, Indiana, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Dmytro Shepilov
- Department of Cytology, Bogomoletz Institute of Physiology, NAS of Ukraine, Kyiv, Ukraine
| | - Galyna Skibo
- Department of Cytology, Bogomoletz Institute of Physiology, NAS of Ukraine, Kyiv, Ukraine
| | | | - Juliet Akkaoui
- Institute of Neuro-immune Medicine, Nova Southeastern University, Ft. Lauderdale, Florida, USA
- Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA
| | - Madepalli K Lakshmana
- Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA
| | - Uma Sankar
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Frank Nichols
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, Connecticut, USA
| | - Bruce T Lamb
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Stanislav Groppa
- Department of Neurology, Institute of Emergency Medicine, Chisinau, Moldova
- Department of Neurology, "Nicolae Testemițanu" State University of Medicine and Pharmacy, Chisinau, Moldova
| | - Alexandru Movila
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, Indiana, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Institute of Neuro-immune Medicine, Nova Southeastern University, Ft. Lauderdale, Florida, USA
- Department of Oral Sciences and Translational Research, College of Dental Medicine, Nova Southeastern University, Davie, Florida, USA
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9
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Subedi L, Gaire BP, Koronyo Y, Koronyo-Hamaoui M, Crother TR. Chlamydia pneumoniae in Alzheimer's disease pathology. Front Neurosci 2024; 18:1393293. [PMID: 38770241 PMCID: PMC11102982 DOI: 10.3389/fnins.2024.1393293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/22/2024] [Indexed: 05/22/2024] Open
Abstract
While recent advances in diagnostics and therapeutics offer promising new approaches for Alzheimer's disease (AD) diagnosis and treatment, there is still an unmet need for an effective remedy, suggesting new avenues of research are required. Besides many plausible etiologies for AD pathogenesis, mounting evidence supports a possible role for microbial infections. Various microbes have been identified in the postmortem brain tissues of human AD patients. Among bacterial pathogens in AD, Chlamydia pneumoniae (Cp) has been well characterized in human AD brains and is a leading candidate for an infectious involvement. However, no definitive studies have been performed proving or disproving Cp's role as a causative or accelerating agent in AD pathology and cognitive decline. In this review, we discuss recent updates for the role of Cp in human AD brains as well as experimental models of AD. Furthermore, based on the current literature, we have compiled a list of potential mechanistic pathways which may connect Cp with AD pathology.
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Affiliation(s)
- Lalita Subedi
- Department of Pediatrics, Division of Infectious Diseases and Immunology, Guerin Children's at Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Infectious and Immunologic Diseases Research Center (IIDRC), Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Bhakta Prasad Gaire
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Yosef Koronyo
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Timothy R. Crother
- Department of Pediatrics, Division of Infectious Diseases and Immunology, Guerin Children's at Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Infectious and Immunologic Diseases Research Center (IIDRC), Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
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10
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Su L, Yang R, Sheng Y, Ullah S, Zhao Y, Shunjiayi H, Zhao Z, Wang Q. Insights into the oral microbiota in human systemic cancers. Front Microbiol 2024; 15:1369834. [PMID: 38756728 PMCID: PMC11098135 DOI: 10.3389/fmicb.2024.1369834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 04/11/2024] [Indexed: 05/18/2024] Open
Abstract
The oral cavity stands as one of the pivotal interfaces facilitating the intricate interaction between the human body and the external environment. The impact of diverse oral microorganisms on the emergence and progression of various systemic cancers, typified by oral cancer, has garnered increasing attention. The potential pathogenicity of oral bacteria, notably the anaerobic Porphyromonas gingivalis and Fusobacterium nucleatum, has been extensively studied and exhibits obvious correlation with different carcinoma types. Furthermore, oral fungi and viruses are closely linked to oropharyngeal carcinoma. Multiple potential mechanisms of oral microbiota-induced carcinogenesis have been investigated, including heightened inflammatory responses, suppression of the host immune system, influence on the tumor microenvironment, anti-apoptotic activity, and promotion of malignant transformation. The disturbance of microbial equilibrium and the migration of oral microbiota play a pivotal role in facilitating oncogenic functions. This review aims to comprehensively outline the pathogenic mechanisms by which oral microbiota participate in carcinogenesis. Additionally, this review delves into their potential applications in cancer prevention, screening, and treatment. It proves to be a valuable resource for researchers investigating the intricate connection between oral microbiota and systemic cancers.
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Affiliation(s)
- Lan Su
- Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province, Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou, Zhejiang, China
| | - Rui Yang
- Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province, Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou, Zhejiang, China
| | - Yanan Sheng
- Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province, Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou, Zhejiang, China
| | - Saif Ullah
- Department of Microbiology School of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Yuheng Zhao
- College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou, Zhejiang, China
| | - Hu Shunjiayi
- School of Stomatology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhuo Zhao
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN, United States
| | - Qingjing Wang
- Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province, Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou, Zhejiang, China
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11
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Rubinstein T, Brickman AM, Cheng B, Burkett S, Park H, Annavajhala MK, Uhlemann A, Andrews H, Gutierrez J, Paster BJ, Noble JM, Papapanou PN. Periodontitis and brain magnetic resonance imaging markers of Alzheimer's disease and cognitive aging. Alzheimers Dement 2024; 20:2191-2208. [PMID: 38278517 PMCID: PMC10984451 DOI: 10.1002/alz.13683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 01/28/2024]
Abstract
INTRODUCTION We examined the association of clinical, microbiological, and host response features of periodontitis with MRI markers of atrophy/cerebrovascular disease in the Washington Heights Inwood Columbia Aging Project (WHICAP) Ancillary Study of Oral Health. METHODS We analyzed 468 participants with clinical periodontal data, microbial plaque and serum samples, and brain MRIs. We tested the association of periodontitis features with MRI features, after adjusting for multiple risk factors for Alzheimer's disease/Alzheimer's disease-related dementia (AD/ADRD). RESULTS In fully adjusted models, having more teeth was associated with lower odds for infarcts, lower white matter hyperintensity (WMH) volume, higher entorhinal cortex volume, and higher cortical thickness. Higher extent of periodontitis was associated with lower entorhinal cortex volume and lower cortical thickness. Differential associations emerged between colonization by specific bacteria/serum antibacterial IgG responses and MRI outcomes. DISCUSSION In an elderly cohort, clinical, microbiological, and serological features of periodontitis were associated with MRI findings related to ADRD risk. Further investigation of causal associations is warranted.
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Affiliation(s)
- Tom Rubinstein
- Division of PeriodonticsSection of OralDiagnostic and Rehabilitation SciencesCollege of Dental MedicineNew YorkNew YorkUSA
| | - Adam M. Brickman
- Department of NeurologyVagelos College of Physicians and SurgeonsNew YorkNew YorkUSA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain and Gertrude H. Sergievsky CenterNew YorkNew YorkUSA
| | - Bin Cheng
- Department of BiostatisticsMailman School of Public HealthNew YorkNew YorkUSA
| | - Sandra Burkett
- Division of PeriodonticsSection of OralDiagnostic and Rehabilitation SciencesCollege of Dental MedicineNew YorkNew YorkUSA
| | - Heekuk Park
- Division of Infectious DiseasesDepartment of MedicineVagelos College of Physicians and, Surgeons, Irving Medical CenterColumbia UniversityNew YorkNew YorkUSA
| | - Medini K. Annavajhala
- Division of Infectious DiseasesDepartment of MedicineVagelos College of Physicians and, Surgeons, Irving Medical CenterColumbia UniversityNew YorkNew YorkUSA
| | - Anne‐Catrin Uhlemann
- Division of Infectious DiseasesDepartment of MedicineVagelos College of Physicians and, Surgeons, Irving Medical CenterColumbia UniversityNew YorkNew YorkUSA
| | - Howard Andrews
- Department of BiostatisticsMailman School of Public HealthNew YorkNew YorkUSA
| | - Jose Gutierrez
- Department of NeurologyVagelos College of Physicians and SurgeonsNew YorkNew YorkUSA
| | - Bruce J. Paster
- The Forsyth InstituteCambridgeMassachusettsUSA
- Department of Oral Medicine, Infection and ImmunityHarvard School of Dental MedicineBostonMassachusettsUSA
| | - James M. Noble
- Department of NeurologyVagelos College of Physicians and SurgeonsNew YorkNew YorkUSA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain and Gertrude H. Sergievsky CenterNew YorkNew YorkUSA
| | - Panos N. Papapanou
- Division of PeriodonticsSection of OralDiagnostic and Rehabilitation SciencesCollege of Dental MedicineNew YorkNew YorkUSA
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12
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Cichońska D, Mazuś M, Kusiak A. Recent Aspects of Periodontitis and Alzheimer's Disease-A Narrative Review. Int J Mol Sci 2024; 25:2612. [PMID: 38473858 DOI: 10.3390/ijms25052612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/13/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Periodontitis is an inflammatory condition affecting the supporting structures of the teeth. Periodontal conditions may increase the susceptibility of individuals to various systemic illnesses, including Alzheimer's disease. Alzheimer's disease is a neurodegenerative condition characterized by a gradual onset and progressive deterioration, making it the primary cause of dementia, although the exact cause of the disease remains elusive. Both Alzheimer's disease and periodontitis share risk factors and clinical studies comparing the associations and occurrence of periodontitis among individuals with Alzheimer's disease have suggested a potential correlation between these conditions. Brains of individuals with Alzheimer's disease have substantiated the existence of microorganisms related to periodontitis, especially Porphyromonas gingivalis, which produces neurotoxic gingipains and may present the capability to breach the blood-brain barrier. Treponema denticola may induce tau hyperphosphorylation and lead to neuronal apoptosis. Lipopolysaccharides-components of bacterial cell membranes and mediators of inflammation-also have an impact on brain function. Further research could unveil therapeutic approaches targeting periodontal pathogens to potentially alleviate AD progression.
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Affiliation(s)
- Dominika Cichońska
- Department of Periodontology and Oral Mucosa Diseases, Medical University of Gdańsk, Orzeszkowej 18 St. 18, 80-208 Gdańsk, Poland
| | - Magda Mazuś
- Student Research Group of the Department of Periodontology and Oral Mucosa Diseases, Medical University of Gdańsk, Orzeszkowej 18 St. 18, 80-208 Gdańsk, Poland
| | - Aida Kusiak
- Department of Periodontology and Oral Mucosa Diseases, Medical University of Gdańsk, Orzeszkowej 18 St. 18, 80-208 Gdańsk, Poland
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13
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Li R, Wang J, Xiong W, Luo Y, Feng H, Zhou H, Peng Y, He Y, Ye Q. The oral-brain axis: can periodontal pathogens trigger the onset and progression of Alzheimer's disease? Front Microbiol 2024; 15:1358179. [PMID: 38362505 PMCID: PMC10868393 DOI: 10.3389/fmicb.2024.1358179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 01/18/2024] [Indexed: 02/17/2024] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by a progressive cognitive decline. Sporadic AD, accounting for more than 95% of cases, may arise due to the influence of environmental factors. It was reported that periodontitis, a common oral ailment, shares several risk factors with AD, including advanced age, smoking, diabetes, and hypertension, among others. Periodontitis is an inflammatory disease triggered by dysbiosis of oral microorganisms, whereas Alzheimer's disease is characterized by neuroinflammation. Many studies have indicated that chronic inflammation can instigate brain AD-related pathologies, including amyloid-β plaques, Tau protein hyperphosphorylation, neuroinflammation, and neurodegeneration. The potential involvement of periodontal pathogens and/or their virulence factors in the onset and progression of AD by the oral-brain axis has garnered significant attention among researchers with ongoing investigations. This review has updated the periodontal pathogens potentially associated with AD, elucidating their impact on the central nervous system, immune response, and related pathological processes in the brain to provide valuable insights for future research on the oral-brain axis.
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Affiliation(s)
- Ruohan Li
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Junnan Wang
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Wei Xiong
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Yu Luo
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Huixian Feng
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Heng Zhou
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Youjian Peng
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Yan He
- Institute of Regenerative and Translational Medicine, Tianyou Hospital, Wuhan University of Science and Technology, Wuhan, China
| | - Qingsong Ye
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
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14
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Na HS, Jung NY, Song Y, Kim SY, Kim HJ, Lee JY, Chung J. A distinctive subgingival microbiome in patients with periodontitis and Alzheimer's disease compared with cognitively unimpaired periodontitis patients. J Clin Periodontol 2024; 51:43-53. [PMID: 37853506 DOI: 10.1111/jcpe.13880] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/04/2023] [Accepted: 09/06/2023] [Indexed: 10/20/2023]
Abstract
AIM Periodontitis is caused by dysbiosis of oral microbes and is associated with increased cognitive decline in Alzheimer's disease (AD), and recently, a potential functional link was proposed between oral microbes and AD. We compared the oral microbiomes of patients with or without AD to evaluate the association between oral microbes and AD in periodontitis. MATERIALS AND METHODS Periodontitis patients with AD (n = 15) and cognitively unimpaired periodontitis patients (CU) (n = 14) were recruited for this study. Each patient underwent an oral examination and neuropsychological evaluation. Buccal, supragingival and subgingival plaque samples were collected, and microbiomes were analysed by next-generation sequencing. Alpha diversity, beta diversity, linear discriminant analysis effect size, analysis of variance-like differential expression analysis and network analysis were used to compare group oral microbiomes. RESULTS All 29 participants had moderate to severe periodontitis. Group buccal and supragingival samples were indistinguishable, but subgingival samples demonstrated significant alpha and beta diversity differences. Differential analysis showed subgingival samples of the AD group had higher prevalence of Atopobium rimae, Dialister pneumosintes, Olsenella sp. HMT 807, Saccharibacteria (TM7) sp. HMT 348 and several species of Prevotella than the CU group. Furthermore, subgingival microbiome network analysis revealed a distinct, closely connected network in the AD group comprised of various Prevotella spp. and several anaerobic bacteria. CONCLUSIONS A unique microbial composition was discovered in the subgingival region in the AD group. Specifically, potential periodontal pathogens were found to be more prevalent in the subgingival plaque samples of the AD group. These bacteria may possess a potential to worsen periodontitis and other systemic diseases. We recommend that AD patients receive regular, careful dental check-ups to ensure proper oral hygiene management.
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Affiliation(s)
- Hee Sam Na
- Department of Oral Microbiology, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
- Oral Genomics Research Center, Pusan National University, Yangsan, Republic of Korea
| | - Na-Yeon Jung
- Department of Neurology, Pusan National University Yangsan Hospital, Pusan National University School of Medicine and Research Institute for Convergence of Biomedical Science and Technology, Yangsan, Republic of Korea
| | - Yuri Song
- Department of Oral Microbiology, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
- Oral Genomics Research Center, Pusan National University, Yangsan, Republic of Korea
| | - Si Yeong Kim
- Department of Oral Microbiology, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
- Oral Genomics Research Center, Pusan National University, Yangsan, Republic of Korea
| | - Hyun-Joo Kim
- Department of Periodontology, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
- Dental Research Institute, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
| | - Ju Youn Lee
- Department of Periodontology, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
- Dental Research Institute, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
| | - Jin Chung
- Department of Oral Microbiology, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
- Oral Genomics Research Center, Pusan National University, Yangsan, Republic of Korea
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15
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Moghadam MT, Mojtahedi A, Bakhshayesh B, Babakhani S, Ajorloo P, Shariati A, Mirzaei M, Heidarzadeh S, Jazi FM. The Effect of Bacterial Composition Shifts in the Oral Microbiota on Alzheimer's Disease. Curr Mol Med 2024; 24:167-181. [PMID: 35986539 DOI: 10.2174/1566524023666220819140748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/16/2022] [Accepted: 05/30/2022] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD), a neurological disorder, despite significant advances in medical science, has not yet been definitively cured, and the exact causes of the disease remain unclear. Due to the importance of AD in the clinic, large expenses are spent annually to deal with this neurological disorder, and neurologists warn of an increase in this disease in elderly in the near future. It has been believed that microbiota dysbiosis leads to Alzheimer's as a multi-step disease. In this regard, the presence of footprints of perturbations in the oral microbiome and the predominance of pathogenic bacteria and their effect on the nervous system, especially AD, is a very interesting topic that has been considered by researchers in the last decade. Some studies have looked at the mechanisms by which oral microbiota cause AD. However, many aspects of this interaction are still unclear as to how oral microbiota composition can contribute to this disease. Understanding this interaction requires extensive collaboration by interdisciplinary researchers to explore all aspects of the issue. In order to reveal the link between the composition of the oral microbiota and this disease, researchers from various domains have sought to explain the mechanisms of shift in oral microbiota in AD in this review.
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Affiliation(s)
- Majid Taati Moghadam
- Student Research Committee, Iran University of Medical Sciences, Tehran, Iran
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Mojtahedi
- Department of Microbiology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Babak Bakhshayesh
- Department of Neurology, Neuroscience Research Center, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Sajad Babakhani
- Department of Microbiology, Tehran North Branch, Islamic Azad University, Tehran, Iran
| | - Parisa Ajorloo
- Department of Biology, Sciences and Research Branch, Islamic Azad University, Tehran, Iran
| | - Aref Shariati
- Molecular and Medicine Research Center, Khomein University of Medical Sciences, Khomein, Iran
| | - Mehrnaz Mirzaei
- Department of Microbiology, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
| | - Siamak Heidarzadeh
- Department of Microbiology and Virology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Faramarz Masjedian Jazi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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16
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Taheri M, Bahrami A, Asadi KK, Mohammadi M, Molaei P, Hashemi M, Nouri F. A review on nonviral, nonbacterial infectious agents toxicity involved in neurodegenerative diseases. Neurodegener Dis Manag 2023; 13:351-369. [PMID: 38357803 DOI: 10.2217/nmt-2023-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Neuronal death, decreased activity or dysfunction of neurotransmitters are some of the pathophysiological reasons for neurodegenerative diseases like Alzheimer's, Parkinson's and multiple sclerosis. Also, there is evidence for the role of infections and infectious agents in neurodegenerative diseases and the effect of some metabolites in microorganisms in the pathophysiology of these diseases. In this study, we intend to evaluate the existing studies on the role of infectious agents and their metabolites on the pathophysiology of neurodegenerative diseases. PubMed, Scopus, Google Scholar and Web of Science search engines were searched. Some infectious agents have been observed in neurodegenerative diseases. Also, isolations of some fungi and microalgae have an improving effect on Parkinson's and Alzheimer's.
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Affiliation(s)
- Mohammad Taheri
- Department of Medical Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Ali Bahrami
- Student Research Committee, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Kiana Kimiaei Asadi
- Student Research Committee, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mojdeh Mohammadi
- Department of Pharmacology & Toxicology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Pejman Molaei
- Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mehrdad Hashemi
- Department of Genetics, Faculty of Advanced Science & Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Fatemeh Nouri
- Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
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17
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Zürcher C, Humpel C. Saliva: a challenging human fluid to diagnose brain disorders with a focus on Alzheimer's disease. Neural Regen Res 2023; 18:2606-2610. [PMID: 37449596 DOI: 10.4103/1673-5374.373675] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023] Open
Abstract
Biomarkers are molecules of biological processes that help in both the diagnosis of human diseases and in follow-up assessments of therapeutic responses. Biomarkers can be measured in many human fluids, such as blood, cerebrospinal fluid, urine, and saliva. The -omics methods (genomics, RNomics, proteomics, and metabolomics) are useful at measuring thousands of markers in a small volume. Saliva is a human fluid that is easily accessible, without any ethical concerns. Yet, saliva remains unexplored in regard to many human disease biomarkers. In this review, we will give an overview on saliva and how it can be influenced by exogenous factors. As we focus on the potential use of saliva as a diagnostic tool in brain disorders (especially Alzheimer's disease), we will cover how saliva is linked to the brain. We will discuss that saliva is a heterogeneous human fluid, yet useful for the discovery of biomarkers in human disorders. However, a procedure and consensus that is controlled, validated, and standardized for the collection and processing of saliva is required, followed by a highly sensitive diagnostic approach.
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Affiliation(s)
- Christine Zürcher
- University Hospital for Restorative Dentistry and Periodontology, Medical University of Innsbruck, Innsbruck, Austria
| | - Christian Humpel
- Laboratory of Psychiatry & Experimental Alzheimer's Research, Department of Psychiatry I, Medical University of Innsbruck, Innsbruck, Austria
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18
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Phuna ZX, Madhavan P. A reappraisal on amyloid cascade hypothesis: the role of chronic infection in Alzheimer's disease. Int J Neurosci 2023; 133:1071-1089. [PMID: 35282779 DOI: 10.1080/00207454.2022.2045290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 02/09/2022] [Indexed: 10/18/2022]
Abstract
Alzheimer disease (AD) is a progressive neurological disorder that accounted for the most common cause of dementia in the elderly population. Lately, 'infection hypothesis' has been proposed where the infection of microbes can lead to the pathogenesis of AD. Among different types of microbes, human immunodeficiency virus-1 (HIV-1), herpes simplex virus-1 (HSV-1), Chlamydia pneumonia, Spirochetes and Candida albicans are frequently detected in the brain of AD patients. Amyloid-beta protein has demonstrated to exhibit antimicrobial properties upon encountering these pathogens. It can bind to microglial cells and astrocytes to activate immune response and neuroinflammation. Nevertheless, HIV-1 and HSV-1 can develop into latency whereas Chlamydia pneumonia, Spirochetes and Candida albicans can cause chronic infections. At this stage, the DNA of microbes remains undetectable yet active. This can act as the prolonged pathogenic stimulus that over-triggers the expression of Aβ-related genes, which subsequently lead to overproduction and deposition of Aβ plaque. This review will highlight the pathogenesis of each of the stated microbial infection, their association in AD pathogenesis as well as the effect of chronic infection in AD progression. Potential therapies for AD by modulating the microbiome have also been suggested. This review will aid in understanding the infectious manifestations of AD.
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Affiliation(s)
- Zhi Xin Phuna
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University, Selangor, Malaysia
| | - Priya Madhavan
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University, Selangor, Malaysia
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19
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Kulkarni MS, Miller BC, Mahani M, Mhaskar R, Tsalatsanis A, Jain S, Yadav H. Poor Oral Health Linked with Higher Risk of Alzheimer's Disease. Brain Sci 2023; 13:1555. [PMID: 38002515 PMCID: PMC10669972 DOI: 10.3390/brainsci13111555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 10/26/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
Alzheimer's disease (AD) is a multifactorial neurodegenerative disease characterized by cognitive and behavioral changes in older adults. Emerging evidence suggests poor oral health is associated with AD, but there is a lack of large-scale clinical studies demonstrating this link. Herein, we used the TriNetX database to generate clinical cohorts and assess the risk of AD and survival among >30 million de-identified subjects with normal oral health (n = 31,418,814) and poor oral health (n = 1,232,751). There was a greater than two-fold increase in AD risk in the poor oral health cohort compared to the normal oral health group (risk ratio (RR): 2.363, (95% confidence interval: 2.326, 2.401)). To reduce potential bias, we performed retrospective propensity score matching for age, gender, and multiple laboratory measures. After matching, the cohorts had no significant differences in survival probability. Furthermore, when comparing multiple oral conditions, diseases related to tooth loss were the most significant risk factor for AD (RR: 3.186, (95% CI: 3.007, 3.376)). Our results suggest that oral health may be important in AD risk, regardless of age, gender, or laboratory measures. However, more large-scale cohort studies are necessary to validate these findings and further evaluate links between oral health and AD.
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Affiliation(s)
- Mihir S. Kulkarni
- USF Center for Microbiome Research, Microbiomes Institute, Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL 33612, USA
| | - Brandi C. Miller
- USF Center for Microbiome Research, Microbiomes Institute, Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL 33612, USA
- USF Center for Microbiome Research, Microbiomes Institute, Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Manan Mahani
- USF Center for Microbiome Research, Microbiomes Institute, Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL 33612, USA
| | - Rahul Mhaskar
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Athanasios Tsalatsanis
- Research Methodology and Biostatistics Core, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Shalini Jain
- USF Center for Microbiome Research, Microbiomes Institute, Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL 33612, USA
| | - Hariom Yadav
- USF Center for Microbiome Research, Microbiomes Institute, Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL 33612, USA
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20
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Wan J, Fan H. Oral Microbiome and Alzheimer's Disease. Microorganisms 2023; 11:2550. [PMID: 37894208 PMCID: PMC10609607 DOI: 10.3390/microorganisms11102550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/06/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
The accumulation of amyloid-beta plaques in the brain is a central pathological feature of Alzheimer's disease. It is believed that amyloid responses may be a result of the host immune response to pathogens in both the central nervous system and peripheral systems. Oral microbial dysbiosis is a chronic condition affecting more than 50% of older adults. Recent studies have linked oral microbial dysbiosis to a higher brain Aβ load and the development of Alzheimer's disease in humans. Moreover, the presence of an oral-derived and predominant microbiome has been identified in the brains of patients with Alzheimer's disease and other neurodegenerative diseases. Therefore, in this opinion article, we aim to provide a summary of studies on oral microbiomes that may contribute to the pathogenesis of the central nervous system in Alzheimer's disease.
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Affiliation(s)
- Jason Wan
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA;
- Charleston County School of the Arts High School, North Charleston, SC 29405, USA
| | - Hongkuan Fan
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA;
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21
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Zhao C, Kuraji R, Ye C, Gao L, Radaic A, Kamarajan P, Taketani Y, Kapila YL. Nisin a probiotic bacteriocin mitigates brain microbiome dysbiosis and Alzheimer's disease-like neuroinflammation triggered by periodontal disease. J Neuroinflammation 2023; 20:228. [PMID: 37803465 PMCID: PMC10557354 DOI: 10.1186/s12974-023-02915-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 09/28/2023] [Indexed: 10/08/2023] Open
Abstract
INTRODUCTION Periodontitis-related oral microbial dysbiosis is thought to contribute to Alzheimer's disease (AD) neuroinflammation and brain amyloid production. Since probiotics can modulate periodontitis/oral dysbiosis, this study examined the effects of a probiotic/lantibiotic, nisin, in modulating brain pathology triggered by periodontitis. METHODS A polymicrobial mouse model of periodontal disease was used to evaluate the effects of this disease on brain microbiome dysbiosis, neuroinflammation, Alzheimer's-related changes, and nisin's therapeutic potential in this context. RESULTS 16S sequencing and real-time PCR data revealed that Nisin treatment mitigated the changes in the brain microbiome composition, diversity, and community structure, and reduced the levels of periodontal pathogen DNA in the brain induced by periodontal disease. Nisin treatment significantly decreased the mRNA expression of pro-inflammatory cytokines (Interleukin-1β/IL-1 β, Interleukin 6/IL-6, and Tumor Necrosis Factor α/TNF-α) in the brain that were elevated by periodontal infection. In addition, the concentrations of amyloid-β 42 (Aβ42), total Tau, and Tau (pS199) (445.69 ± 120.03, 1420.85 ± 331.40, 137.20 ± 36.01) were significantly higher in the infection group compared to the control group (193.01 ± 31.82, 384.27 ± 363.93, 6.09 ± 10.85), respectively. Nisin treatment markedly reduced the Aβ42 (261.80 ± 52.50), total Tau (865.37 ± 304.93), and phosphorylated Tau (82.53 ± 15.77) deposition in the brain of the infection group. DISCUSSION Nisin abrogation of brain microbiome dysbiosis induces beneficial effects on AD-like pathogenic changes and neuroinflammation, and thereby may serve as a potential therapeutic for periodontal-dysbiosis-related AD.
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Affiliation(s)
- Chuanjiang Zhao
- Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA, 94143, USA
- Department of Periodontology, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510050, China
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510050, China
| | - Ryutaro Kuraji
- Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA, 94143, USA
- Department of Periodontology, The Nippon Dental University School of Life Dentistry at Tokyo, Tokyo, 102-8159, Japan
| | - Changchang Ye
- Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA, 94143, USA
- Department of Periodontology, West China School of Stomatology, National Clinical Research Center for Oral Diseases, State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, 610093, China
| | - Li Gao
- Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA, 94143, USA
- Department of Periodontology, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510050, China
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510050, China
| | - Allan Radaic
- Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA, 94143, USA
- Department of Biosystems and Function and Periodontics, School of Dentistry, University of California Los Angeles, Los Angeles, CA, 90024, USA
| | - Pachiyappan Kamarajan
- Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA, 94143, USA
- Department of Biosystems and Function and Periodontics, School of Dentistry, University of California Los Angeles, Los Angeles, CA, 90024, USA
| | - Yoshimasa Taketani
- Department of Biosystems and Function and Periodontics, School of Dentistry, University of California Los Angeles, Los Angeles, CA, 90024, USA
- Division of Periodontology, Department of Oral Biology and Tissue Engineering, Meikai University School of Dentistry, Sakado, 350-0283, Japan
| | - Yvonne L Kapila
- Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA, 94143, USA.
- Department of Biosystems and Function and Periodontics, School of Dentistry, University of California Los Angeles, Los Angeles, CA, 90024, USA.
- Section of Biosystems and Function, Section of Periodontology, UCLA School of Dentistry, 10833 Le Conte Ave, Box 951668, Los Angeles, CA, 90095-1668, USA.
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22
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Tang Y, Zhang D, Zheng J. Repurposing Antimicrobial Protegrin-1 as a Dual-Function Amyloid Inhibitor via Cross-seeding. ACS Chem Neurosci 2023; 14:3143-3155. [PMID: 37589476 DOI: 10.1021/acschemneuro.3c00293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023] Open
Abstract
Amyloids and antimicrobial peptides have traditionally been recognized as distinct families with separate biological functions and targets. However, certain amyloids and antimicrobial peptides share structural and functional characteristics that contribute to the development of neurodegenerative diseases. Specifically, the aggregation of amyloid-β (Aβ) and microbial infections are interconnected pathological factors in Alzheimer's disease (AD). In this study, we propose and demonstrate a novel repurposing strategy for an antimicrobial peptide of protegrin-1 (PG-1), which exhibits the ability to simultaneously prevent Aβ aggregation and microbial infection both in vitro and in vivo. Through a comprehensive analysis using protein, cell, and worm assays, we uncover multiple functions of PG-1 against Aβ, including the following: (i) complete inhibition of Aβ aggregation at a low molar ratio of PG-1/Aβ = 0.25:1, (ii) disassembly of the preformed Aβ fibrils into amorphous aggregates, (iii) reduction of Aβ-induced cytotoxicity in SH-SY5Y cells and transgenic GMC101 nematodes, and (iv) preservation of original antimicrobial activity against P.A., E.coli., S.A., and S.E. strains in the presence of Aβ. Mechanistically, the dual anti-amyloid and anti-bacterial functions of PG-1 primarily arise from its strong binding to distinct Aβ seeds (KD = 1.24-1.90 μM) through conformationally similar β-sheet associations. This work introduces a promising strategy to repurpose antimicrobial peptides as amyloid inhibitors, effectively targeting multiple pathological pathways in AD.
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Affiliation(s)
- Yijing Tang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Dong Zhang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Jie Zheng
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States
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23
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Chen Q, Wang Y, Shuai J. Current status and future prospects of stomatology research. J Zhejiang Univ Sci B 2023; 24:853-867. [PMID: 37752088 PMCID: PMC10522564 DOI: 10.1631/jzus.b2200702] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 03/27/2023] [Indexed: 08/08/2023]
Abstract
Research in stomatology (dental medicine) continues to expand globally and is oriented towards solving clinical issues, focusing on clarifying the clinical relevance and potential mechanisms of oral-systemic connections via clinical epidemiology, oral microecological characterization, and the establishment of animal models. Interdisciplinary integration of materials science and tissue engineering with stomatology is expected to lead to the creation of innovative materials and technologies to better resolve the most prevalent and challenging clinical issues such as peri-implantitis, soft and hard tissue defects, and dentin hypersensitivity. With the rapid development of artificial intelligence (AI), 5th generation mobile communication technology (5G), and big data applications, "intelligent stomatology" is emerging to build models for better clinical diagnosis and management, accelerate the reform of education, and support the growth and advancement of scientific research. Here, we summarized the current research status, and listed the future prospects and limitations of these three aspects, aiming to provide a basis for more accurate etiological exploration, novel treatment methods, and abundant big data analysis in stomatology to promote the translation of research achievements into practical applications for both clinicians and the public.
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Affiliation(s)
- Qianming Chen
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Clinical Research Center for Oral Diseases of Zhejiang Province, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, China.
| | - Yahui Wang
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Clinical Research Center for Oral Diseases of Zhejiang Province, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, China
| | - Jing Shuai
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Clinical Research Center for Oral Diseases of Zhejiang Province, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, China
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24
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Catumbela CSG, Giridharan VV, Barichello T, Morales R. Clinical evidence of human pathogens implicated in Alzheimer's disease pathology and the therapeutic efficacy of antimicrobials: an overview. Transl Neurodegener 2023; 12:37. [PMID: 37496074 PMCID: PMC10369764 DOI: 10.1186/s40035-023-00369-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/05/2023] [Indexed: 07/28/2023] Open
Abstract
A wealth of pre-clinical reports and data derived from human subjects and brain autopsies suggest that microbial infections are relevant to Alzheimer's disease (AD). This has inspired the hypothesis that microbial infections increase the risk or even trigger the onset of AD. Multiple models have been developed to explain the increase in pathogenic microbes in AD patients. Although this hypothesis is well accepted in the field, it is not yet clear whether microbial neuroinvasion is a cause of AD or a consequence of the pathological changes experienced by the demented brain. Along the same line, the gut microbiome has also been proposed as a modulator of AD. In this review, we focus on human-based evidence demonstrating the elevated abundance of microbes and microbe-derived molecules in AD hosts as well as their interactions with AD hallmarks. Further, the direct-purpose and potential off-target effects underpinning the efficacy of anti-microbial treatments in AD are also addressed.
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Affiliation(s)
- Celso S G Catumbela
- Department of Neurology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Vijayasree V Giridharan
- Translational Psychiatry Program, Faillace Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Tatiana Barichello
- Translational Psychiatry Program, Faillace Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
- Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, 88806-000, Brazil
| | - Rodrigo Morales
- Department of Neurology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
- Centro Integrativo de Biologia y Quimica Aplicada (CIBQA), Universidad Bernardo O'Higgins, 8370993, Santiago, Chile.
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25
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Almarhoumi R, Alvarez C, Harris T, Tognoni CM, Paster BJ, Carreras I, Dedeoglu A, Kantarci A. Microglial cell response to experimental periodontal disease. J Neuroinflammation 2023; 20:142. [PMID: 37316834 PMCID: PMC10265806 DOI: 10.1186/s12974-023-02821-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/29/2023] [Indexed: 06/16/2023] Open
Abstract
OBJECTIVES Microglial activation is critical for modulating the neuroinflammatory process and the pathological progression of neurodegenerative diseases, such as Alzheimer's disease (AD). Microglia are involved in forming barriers around extracellular neuritic plaques and the phagocytosis of β-amyloid peptide (Aβ). In this study, we tested the hypothesis that periodontal disease (PD) as a source of infection alters inflammatory activation and Aβ phagocytosis by the microglial cells. METHODS Experimental PD was induced using ligatures in C57BL/6 mice for 1, 10, 20, and 30 days to assess the progression of PD. Animals without ligatures were used as controls. Maxillary bone loss and local periodontal tissue inflammation associated with the development of PD were confirmed by morphometric bone analysis and cytokine expression, respectively. The frequency and the total number of activated microglia (CD45+ CD11b+ MHCII+) in the brain were analyzed by flow cytometry. Mouse microglial cells (1 × 105) were incubated with heat-inactivated bacterial biofilm isolated from the ligatures retrieved from the teeth or with Klebsiella variicola, a relevant PD-associated bacteria in mice. Expression of pro-inflammatory cytokines, toll-like receptors (TLR), and receptors for phagocytosis was measured by quantitative PCR. The phagocytic capacity of microglia to uptake β-amyloid was analyzed by flow cytometry. RESULTS Ligature placement caused progressive periodontal disease and bone resorption that was already significant on day 1 post-ligation (p < 0.05) and continued to increase until day 30 (p < 0.0001). The severity of periodontal disease increased the frequency of activated microglia in the brains on day 30 by 36%. In parallel, heat-inactivated PD-associated total bacteria and Klebsiella variicola increased the expression of TNFα, IL-1β, IL-6, TLR2, and TLR9 in microglial cells (1.6-, 83-, 3.2-, 1.5-, 1.5-fold, respectively p < 0.01). Incubation of microglia with Klebsiella variicola increased the Aβ-phagocytosis by 394% and the expression of the phagocytic receptor MSR1 by 33-fold compared to the non-activated cells (p < 0.0001). CONCLUSIONS We showed that inducing PD in mice results in microglia activation in vivo and that PD-associated bacteria directly promote a pro-inflammatory and phagocytic phenotype in microglia. These results support a direct role of PD-associated pathogens in neuroinflammation.
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Affiliation(s)
- Rawan Almarhoumi
- Forsyth Institute, 245 First Street, Cambridge, MA 02142 USA
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115 USA
- Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Carla Alvarez
- Forsyth Institute, 245 First Street, Cambridge, MA 02142 USA
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115 USA
| | - Theodore Harris
- Forsyth Institute, 245 First Street, Cambridge, MA 02142 USA
| | - Christina M. Tognoni
- Department of Veterans Affairs, VA Boston Healthcare System, Research and Development Service, Building 1A-(151), 150 S. Huntington Avenue, Boston, MA 02130 USA
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118 USA
| | - Bruce J. Paster
- Forsyth Institute, 245 First Street, Cambridge, MA 02142 USA
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115 USA
| | - Isabel Carreras
- Department of Veterans Affairs, VA Boston Healthcare System, Research and Development Service, Building 1A-(151), 150 S. Huntington Avenue, Boston, MA 02130 USA
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118 USA
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118 USA
| | - Alpaslan Dedeoglu
- Department of Veterans Affairs, VA Boston Healthcare System, Research and Development Service, Building 1A-(151), 150 S. Huntington Avenue, Boston, MA 02130 USA
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118 USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 USA
| | - Alpdogan Kantarci
- Forsyth Institute, 245 First Street, Cambridge, MA 02142 USA
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115 USA
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26
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Pisani F, Pisani V, Arcangeli F, Harding A, Singhrao SK. Treponema denticola Has the Potential to Cause Neurodegeneration in the Midbrain via the Periodontal Route of Infection-Narrative Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6049. [PMID: 37297653 PMCID: PMC10252855 DOI: 10.3390/ijerph20116049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/30/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease and the most common example of dementia. The neuropathological features of AD are the abnormal deposition of extracellular amyloid-β (Aβ) and intraneuronal neurofibrillary tangles with hyperphosphorylated tau protein. It is recognized that AD starts in the frontal cerebral cortex, and then it progresses to the entorhinal cortex, the hippocampus, and the rest of the brain. However, some studies on animals suggest that AD could also progress in the reverse order starting from the midbrain and then spreading to the frontal cortex. Spirochetes are neurotrophic: From a peripheral route of infection, they can reach the brain via the midbrain. Their direct and indirect effect via the interaction of their virulence factors and the microglia potentially leads to the host peripheral nerve, the midbrain (especially the locus coeruleus), and cortical damage. On this basis, this review aims to discuss the hypothesis of the ability of Treponema denticola to damage the peripheral axons in the periodontal ligament, to evade the complemental pathway and microglial immune response, to determine the cytoskeletal impairment and therefore causing the axonal transport disruption, an altered mitochondrial migration and the consequent neuronal apoptosis. Further insights about the central neurodegeneration mechanism and Treponema denticola's resistance to the immune response when aggregated in biofilm and its quorum sensing are suggested as a pathogenetic model for the advanced stages of AD.
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Affiliation(s)
- Flavio Pisani
- Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - Valerio Pisani
- IRCCS, “Santa Lucia” Foundation, Neurology and Neurorehabilitation Unit, Via Ardeatina, 306, 00179 Rome, Italy
| | - Francesca Arcangeli
- Azienda Sanitaria Locale ASLRM1, Nuovo Regina Margherita Hospital, Geriatric Department, Advanced Centre for Dementia and Cognitive Disorders, Via Emilio Morosini, 30, 00153 Rome, Italy
| | - Alice Harding
- Dementia and Neurodegenerative Disease Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - Simarjit Kaur Singhrao
- Dementia and Neurodegenerative Disease Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
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27
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Weber C, Dilthey A, Finzer P. The role of microbiome-host interactions in the development of Alzheimer´s disease. Front Cell Infect Microbiol 2023; 13:1151021. [PMID: 37333848 PMCID: PMC10272569 DOI: 10.3389/fcimb.2023.1151021] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/16/2023] [Indexed: 06/20/2023] Open
Abstract
Alzheimer`s disease (AD) is the most prevalent cause of dementia. It is often assumed that AD is caused by an aggregation of extracellular beta-amyloid and intracellular tau-protein, supported by a recent study showing reduced brain amyloid levels and reduced cognitive decline under treatment with a beta-amyloid-binding antibody. Confirmation of the importance of amyloid as a therapeutic target notwithstanding, the underlying causes of beta-amyloid aggregation in the human brain, however, remain to be elucidated. Multiple lines of evidence point towards an important role of infectious agents and/or inflammatory conditions in the etiology of AD. Various microorganisms have been detected in the cerebrospinal fluid and brains of AD-patients and have thus been hypothesized to be linked to the development of AD, including Porphyromonas gingivalis (PG) and Spirochaetes. Intriguingly, these microorganisms are also found in the oral cavity under normal physiological conditions, which is often affected by multiple pathologies like caries or tooth loss in AD patients. Oral cavity pathologies are mostly accompanied by a compositional shift in the community of oral microbiota, mainly affecting commensal microorganisms and referred to as 'dysbiosis'. Oral dysbiosis seems to be at least partly mediated by key pathogens such as PG, and it is associated with a pro-inflammatory state that promotes the destruction of connective tissue in the mouth, possibly enabling the translocation of pathogenic microbiota from the oral cavity to the nervous system. It has therefore been hypothesized that dysbiosis of the oral microbiome may contribute to the development of AD. In this review, we discuss the infectious hypothesis of AD in the light of the oral microbiome and microbiome-host interactions, which may contribute to or even cause the development of AD. We discuss technical challenges relating to the detection of microorganisms in relevant body fluids and approaches for avoiding false-positives, and introduce the antibacterial protein lactoferrin as a potential link between the dysbiotic microbiome and the host inflammatory reaction.
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28
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Schamarek I, Anders L, Chakaroun RM, Kovacs P, Rohde-Zimmermann K. The role of the oral microbiome in obesity and metabolic disease: potential systemic implications and effects on taste perception. Nutr J 2023; 22:28. [PMID: 37237407 DOI: 10.1186/s12937-023-00856-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Obesity and its metabolic sequelae still comprise a challenge when it comes to understanding mechanisms, which drive these pandemic diseases. The human microbiome as a potential key player has attracted the attention of broader research for the past decade. Most of it focused on the gut microbiome while the oral microbiome has received less attention. As the second largest niche, the oral microbiome is associated with a multitude of mechanisms, which are potentially involved in the complex etiology of obesity and associated metabolic diseases. These mechanisms include local effects of oral bacteria on taste perception and subsequent food preference as well as systemic effects on adipose tissue function, the gut microbiome and systemic inflammation. This review summarizes a growing body of research, pointing towards a more prominent role of the oral microbiome in obesity and associated metabolic diseases than expected. Ultimately, our knowledge on the oral microbiome may support the development of new patient oriented therapeutic approaches inevitable to relieve the health burden of metabolic diseases and to reach long-term benefits in patients´ lives.
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Affiliation(s)
- Imke Schamarek
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG), Helmholtz Center Munich at the University Leipzig and the University Clinic Leipzig, AöR, Liebigstraße 20, 04103, Leipzig, Germany.
- Department of Medicine III, Division of Endocrinology, Nephrology and Rheumatology, University of Leipzig, Liebigstraße 20, 04103, Leipzig, Germany.
| | - Lars Anders
- Department of Medicine III, Division of Endocrinology, Nephrology and Rheumatology, University of Leipzig, Liebigstraße 20, 04103, Leipzig, Germany
| | - Rima M Chakaroun
- Department of Medicine III, Division of Endocrinology, Nephrology and Rheumatology, University of Leipzig, Liebigstraße 20, 04103, Leipzig, Germany
- The Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 41345, Gothenburg, Sweden
| | - Peter Kovacs
- Department of Medicine III, Division of Endocrinology, Nephrology and Rheumatology, University of Leipzig, Liebigstraße 20, 04103, Leipzig, Germany
- Deutsches Zentrum Für Diabetesforschung, 85764, Neuherberg, Germany
| | - Kerstin Rohde-Zimmermann
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG), Helmholtz Center Munich at the University Leipzig and the University Clinic Leipzig, AöR, Liebigstraße 20, 04103, Leipzig, Germany
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29
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Li L, Zhang Q, Yang D, Yang S, Zhao Y, Jiang M, Wang X, Zhao L, Liu Q, Lu Z, Zhou X, Gan Y, Wu C. Tooth loss and the risk of cognitive decline and dementia: A meta-analysis of cohort studies. Front Neurol 2023; 14:1103052. [PMID: 37139053 PMCID: PMC10150074 DOI: 10.3389/fneur.2023.1103052] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 03/13/2023] [Indexed: 05/05/2023] Open
Abstract
Introduction Epidemiological studies have shown that tooth loss may be associated with an increased risk of cognitive decline and dementia. However, some results do not show a significant association. Therefore, we performed a meta-analysis to evaluate this association. Methods Relevant cohort studies were searched in PubMed, Embase, Web of Science (up to May 2022), and the reference lists of retrieved articles. The pooled relative risk (RR) and 95% confidence intervals were computed using a random-effects model (CI). Heterogeneity was evaluated using the I 2 statistic. Publication bias was evaluated using the Begg's and Egger's tests. Results Eighteen cohort studies met the inclusion criteria. Original studies with 356,297 participants with an average follow-up of 8.6 years (ranging from 2 to 20 years) were included in this study. The pooled RRs of tooth loss on dementia and cognitive decline were 1.15 (95% CI: 1.10-1.20; P < 0.01, I 2 = 67.4%) and 1.20 (95% CI: 1.14-1.26; P = 0.04, I 2 = 42.3%), respectively. The results of the subgroup analysis showed an increased association between tooth loss and Alzheimer's disease (AD) (RR = 1.12, 95% CI: 1.02-1.23) and vascular dementia (VaD) (RR = 1.25, 95% CI: 1.06-1.47). The results of the subgroup analysis also showed that pooled RRs varied by geographic location, sex, use of dentures, number of teeth or edentulous status, dental assessment, and follow-up duration. None of the Begg's and Egger's tests or funnel plots showed evidence of publication bias. Discussion Tooth loss is associated with a significantly increased risk of cognitive decline and dementia, suggesting that adequate natural teeth are important for cognitive function in older adults. The likely mechanisms mostly suggested include nutrition, inflammation, and neural feedback, especially deficiency of several nutrients like vitamin D.
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Affiliation(s)
- Liqing Li
- Research Center of Health Policy and Innovation, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
- School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Qi Zhang
- Research Center of Health Policy and Innovation, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
| | - Di Yang
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, Jiangxi, China
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, Jiangxi, China
| | - Sule Yang
- Research Center of Health Policy and Innovation, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
| | - Yulan Zhao
- Research Center of Health Policy and Innovation, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
| | - Min Jiang
- Research Center of Health Policy and Innovation, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
| | - Xiaofang Wang
- Research Center of Health Policy and Innovation, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
| | - Ling Zhao
- Research Center of Health Policy and Innovation, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
| | - Qi Liu
- Research Center of Health Policy and Innovation, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China
| | - Zuxun Lu
- School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xiaogang Zhou
- School of Economics and Management, East China Jiaotong University, Nanchang, Jiangxi, China
| | - Yong Gan
- School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chunmei Wu
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, Jiangxi, China
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, Jiangxi, China
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30
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Guo H, Li B, Yao H, Liu D, Chen R, Zhou S, Ji Y, Zeng L, Du M. Profiling the oral microbiomes in patients with Alzheimer's disease. Oral Dis 2023; 29:1341-1355. [PMID: 34931394 DOI: 10.1111/odi.14110] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 12/10/2021] [Accepted: 12/16/2021] [Indexed: 01/15/2023]
Abstract
OBJECTIVES To analyse the characteristics of the oral microbiomes and expected to find biomarkers about Alzheimer's disease (AD). SUBJECTS AND METHODS AD patients (n = 26) and cognitive intact people (n = 26) were examined for cognition, depression, oral health and collected saliva and gingival crevicular fluid (GCF) in the morning. Full-length 16S rRNA gene was amplified and sequencing was performed using the PacBio platform. RESULTS The predominant bacterium of salivary microbiome and periodontal microbiome from AD patients was Streptococcus oralis and Porphyromonas gingivalis, respectively. With respect to β diversity analysis, there was a significance difference in periodontal microbiome between AD patients and cognitively intact subjects. The relative abundance of Veillonella parvula significantly increased in oral microbiomes from AD patients. Interestingly, the dominant species were different between early-onset AD and late-onset AD patients. Moreover, the predominant species were changed as the clinical severity of AD. Furthermore, the correlation analysis revealed that V. parvula was associated with AD in both saliva and GCF and that P. gingivalis was associated with AD only in GCF. CONCLUSIONS In this study, the microbiome community of oral microbes was altered in AD patients and periodontal microbiome was sensitive to cognition changes. Moreover, V. parvula and P. gingivalis were associated with AD.
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Affiliation(s)
- Haiying Guo
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Biao Li
- Wuhan Mental Health Center, Wuhan, Hubei, China
| | - Hantao Yao
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Danfeng Liu
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Rourong Chen
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Shuhui Zhou
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Yaoting Ji
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Lin Zeng
- Wuhan Mental Health Center, Wuhan, Hubei, China
| | - Minquan Du
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
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Wang RPH, Huang J, Chan KWY, Leung WK, Goto T, Ho YS, Chang RCC. IL-1β and TNF-α play an important role in modulating the risk of periodontitis and Alzheimer's disease. J Neuroinflammation 2023; 20:71. [PMID: 36915108 PMCID: PMC10012546 DOI: 10.1186/s12974-023-02747-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 02/21/2023] [Indexed: 03/16/2023] Open
Abstract
BACKGROUND Systemic activation of the immune system can exert detrimental effects on the central nervous system. Periodontitis, a chronic disease of the oral cavity, is a common source of systemic inflammation. Neuroinflammation might be a result of this to accelerate progressive deterioration of neuronal functions during aging or exacerbate pre-existing neurodegenerative diseases, such as Alzheimer's disease. With advancing age, the progressive increase in the body's pro-inflammatory status favors the state of vulnerability to both periodontitis and Alzheimer's disease. In the present study, we sought to delineate the roles of cytokines in the pathogenesis of both diseases. METHODS To examine the impacts of periodontitis on the onset and progression of Alzheimer's disease, 6-month-old female 3 × Tg-AD mice and their age-matched non-transgenic mice were employed. Periodontitis was induced using two different experimental models: heat-killed bacterial-induced periodontitis and ligature-induced periodontitis. To delineate the roles of pro-inflammatory cytokines in the pathogenesis of periodontitis and Alzheimer's disease, interleukin 1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were also injected into the buccal mandibular vestibule of mice. RESULTS Here, we show that IL-1β and TNF-α were two of the most important and earliest cytokines upregulated upon periodontal infection. The systemic upregulation of these two cytokines promoted a pro-inflammatory environment in the brain contributing to the development of Alzheimer's disease-like pathology and cognitive dysfunctions. Periodontitis-induced systemic inflammation also enhanced brain inflammatory responses and subsequently exacerbated Alzheimer's disease pathology and cognitive impairment in 3 × Tg-AD mice. The role of inflammation in connecting periodontitis to Alzheimer's disease was further affirmed in the conventional magnetization transfer experiment in which increased glial responses resulting from periodontitis led to decreased magnetization transfer ratios in the brain of 3 × Tg-AD mice. CONCLUSIONS Systemic inflammation resulting from periodontitis contributed to the development of Alzheimer's disease tau pathology and subsequently led to cognitive decline in non-transgenic mice. It also potentiated Alzheimer's disease pathological features and exacerbated impairment of cognitive function in 3 × Tg-AD mice. Taken together, this study provides convincing evidence that systemic inflammation serves as a connecting link between periodontitis and Alzheimer's disease.
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Affiliation(s)
- Rachel Pei-Hsuan Wang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Laboratory Block, Rm. L4-49, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Jianpan Huang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - Kannie Wai Yan Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - Wai Keung Leung
- Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Tetsuya Goto
- Division of Oral Anatomy and Histology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Yuen-Shan Ho
- School of Nursing, Faculty of Health and Social Sciences, Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong SAR, China
| | - Raymond Chuen-Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Laboratory Block, Rm. L4-49, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China. .,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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Said-Sadier N, Sayegh B, Farah R, Abbas LA, Dweik R, Tang N, Ojcius DM. Association between Periodontal Disease and Cognitive Impairment in Adults. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:4707. [PMID: 36981618 PMCID: PMC10049038 DOI: 10.3390/ijerph20064707] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/12/2023] [Accepted: 02/12/2023] [Indexed: 06/18/2023]
Abstract
INTRODUCTION Periodontitis is a severe oral infection that can contribute to systemic inflammation. A large body of evidence suggests a role for systemic inflammation in the initiation of neurodegenerative disease. This systematic review synthesized data from observational studies to investigate the association between periodontitis and neuroinflammation in adults. METHODS AND MATERIALS A systematic literature search of PubMed, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) was performed for studies published from the date of inception up to September 2021. Search terms for the exposure "oral disease" and outcome "dementia", "neuroinflammation" and "cognitive decline" were used. Study selection and data extraction were independently undertaken by two reviewers. The final eligible articles were included only if the exposure is periodontitis and the outcome is cognitive impairment or dementia or a topic related to this condition, and if the study was conducted in an adult population. The quality and risk of bias were assessed by Newcastle Ottawa Scale (NOS). Qualitative synthesis was used to narratively synthesize the results. Six cohort studies, three cross-sectional studies, and two case-control studies met the inclusion criteria. These eleven studies were only narratively synthesized. Meta-analysis was not performed due to the methodological heterogeneity of the studies. RESULTS The results of included studies show that chronic periodontitis patients with at least eight years of exposure are at higher risk of developing cognitive decline and dementia. Oral health measures such as gingival inflammation, attachment loss, probing depth, bleeding on probing, and alveolar bone loss are associated with cognitive impairment. The reduction of epidermal growth factor (EGF), interleukin 8 (IL-8), interferon γ-induced protein 10 (IP-10), and monocyte chemoattractant protein-1 (MCP-1) in addition to over expression of interleukin 1-β (IL-1β) are significant in patients suffering from cognitive decline with pre-existing severe periodontitis. CONCLUSIONS All the included studies show evidence of an association between periodontitis and cognitive impairment or dementia and Alzheimer's disease pathology. Nonetheless, the mechanisms responsible for the association between periodontitis and dementia are still unclear and warrant further investigation.
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Affiliation(s)
- Najwane Said-Sadier
- College of Health Sciences, Abu Dhabi University, Abu Dhabi 59911, United Arab Emirates
| | - Batoul Sayegh
- Neuroscience Research Center (NRC), Lebanese University, Beirut 1533, Lebanon
| | - Raymond Farah
- Neuroscience Research Center (NRC), Lebanese University, Beirut 1533, Lebanon
| | - Linda Abou Abbas
- Neuroscience Research Center (NRC), Lebanese University, Beirut 1533, Lebanon
- INSPECT-LB (Institut National de Santé Publique, d’Épidémiologie Clinique et de Toxicologie-Liban), Beirut 1103, Lebanon
| | - Rania Dweik
- College of Health Sciences, Abu Dhabi University, Abu Dhabi 59911, United Arab Emirates
| | - Norina Tang
- Department of Periodontics, University of the Pacific, San Francisco, CA 94103, USA
- Department of Laboratory Medicine, Veterans Affairs Medical Center, San Francisco, CA 94121, USA
- Arthur Dugoni School of Dentistry, University of the Pacific, San Francisco, CA 94103, USA
| | - David M. Ojcius
- Arthur Dugoni School of Dentistry, University of the Pacific, San Francisco, CA 94103, USA
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Matuck B, Ferraz da Silva LF, Warner BM, Byrd KM. The need for integrated research autopsies in the era of precision oral medicine. J Am Dent Assoc 2023; 154:194-205. [PMID: 36710158 PMCID: PMC9974796 DOI: 10.1016/j.adaj.2022.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/18/2022] [Accepted: 11/20/2022] [Indexed: 01/29/2023]
Abstract
BACKGROUND Autopsy has benefited the practice of medicine for centuries; however, its use to advance the practice of oral health care is relatively limited. In the era of precision oral medicine, the research autopsy is poised to play an important role in understanding oral-systemic health, including infectious disease, autoimmunity, craniofacial genetics, and cancer. TYPES OF STUDIES REVIEWED The authors reviewed relevant articles that used medical and dental research autopsies to summarize the advantages of minimally invasive autopsies of dental, oral, and craniofacial tissues and to outline practices for supporting research autopsies of the oral and craniofacial complex. RESULTS The authors provide a historical summary of research autopsy in dentistry and provide a perspective on the value of autopsies for high-resolution multiomic studies to benefit precision oral medicine. As the promise of high-resolution multiomics is being realized, there is a need to integrate the oral and craniofacial complex into the practice of autopsy in medicine. Furthermore, the collaboration of autopsy centers with researchers will accelerate the understanding of dental, oral, and craniofacial tissues as part of the whole body. CONCLUSIONS Autopsies must integrate oral and craniofacial tissues as part of biobanking procedures. As new technologies allow for high-resolution, multimodal phenotyping of human samples, using optimized sampling procedures will allow for unprecedented understanding of common and rare dental, oral, and craniofacial diseases in the future. PRACTICAL IMPLICATIONS The COVID-19 pandemic highlighted the oral cavity as a site for viral infection and transmission potential; this was only discovered via clinical autopsies. The realization of the integrated autopsy's value in full body health initiatives will benefit patients across the globe.
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Affiliation(s)
- Bruno Matuck
- Department of Pathology, School of Medicine University of São Paulo, São Paulo, Brazil
- Division of Oral and Craniofacial Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Blake M. Warner
- Salivary Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Kevin Matthew Byrd
- Salivary Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
- Division of Oral and Craniofacial Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lab of Oral & Craniofacial Innovation (LOCI), Department of Innovation and Technology Research, ADA Science & Research Institute, Gaithersburg, MD, USA
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Fogelholm N, Leskelä J, Manzoor M, Holmer J, Paju S, Hiltunen K, Roitto HM, Saarela RK, Pitkälä K, Eriksdotter M, Buhlin K, Pussinen PJ, Mäntylä P. Subgingival microbiome at different levels of cognition. J Oral Microbiol 2023; 15:2178765. [PMID: 36844899 PMCID: PMC9946326 DOI: 10.1080/20002297.2023.2178765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Oral health and declining cognition may have a bi-directional association. We characterized the subgingival microbiota composition of subjects from normal cognition to severe cognitive decline in two cohorts. Memory and Periodontitis (MINOPAR) include 202 home-living participants (50-80 years) in Sweden. Finnish Oral Health Studies in Older Adults (FINORAL) include 174 participants (≥65 years) living in long-term care in Finland. We performed oral examination and assessed the cognitive level with Mini Mental State Examination (MMSE). We sequenced the 16S-rRNA gene (V3-V4 regions) to analyse the subgingival bacterial compositions. The microbial diversities only tended to differ between the MMSE categories, and the strongest determinants were increased probing pocket depth (PPD) and presence of caries. However, abundances of 101 taxa were associated with the MMSE score. After adjusting for age, sex, medications, PPD, and caries, only eight taxa retained the significance in the meta-analyses of the two cohorts. Especially Lachnospiraceae [XIV] at the family, genus, and species level increased with decreasing MMSE. Cognitive decline is associated with obvious changes in the composition of the oral microbiota. Impaired cognition is accompanied with poor oral health status and the appearance of major taxa of the gut microbiota in the oral cavity. Good oral health-care practices require special deliberations among older adults.
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Affiliation(s)
- Nele Fogelholm
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Jaakko Leskelä
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Muhammed Manzoor
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Jacob Holmer
- Division of Periodontology, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Susanna Paju
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Kaija Hiltunen
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Hanna-Maria Roitto
- Department of Neurosciences, University of Helsinki, Helsinki, Finland.,Internal medicine and rehabilitation, Division of Geriatrics, Helsinki University Hospital Helsinki, Finland.,Population health unit, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Riitta Kt Saarela
- Department of Social Services and Health Care, Oral Health Care, Helsinki, Finland
| | - Kaisu Pitkälä
- Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland.,Unit of Primary Health Care, Helsinki University Hospital, Helsinki, Finland
| | - Maria Eriksdotter
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.,Theme Inflammation and Aging, Karolinska University Hospital, Huddinge, Sweden
| | - Kåre Buhlin
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland.,Division of Periodontology, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Pirkko J Pussinen
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland.,School of Medicine, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland
| | - Päivi Mäntylä
- School of Medicine, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland.,Oral and Maxillofacial Diseases, Kuopio University Hospital, Kuopio, Finland
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Liu S, Dashper SG, Zhao R. Association Between Oral Bacteria and Alzheimer's Disease: A Systematic Review and Meta-Analysis. J Alzheimers Dis 2023; 91:129-150. [PMID: 36404545 DOI: 10.3233/jad-220627] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Pre-clinical evidence implicates oral bacteria in the pathogenesis of Alzheimer's disease (AD), while clinical studies show diverse results. OBJECTIVE To comprehensively assess the association between oral bacteria and AD with clinical evidence. METHODS Studies investigating the association between oral bacteria and AD were identified through a systematic search of six databases PubMed, Embase, Cochrane Central Library, Scopus, ScienceDirect, and Web of Science. Methodological quality ratings of the included studies were performed. A best evidence synthesis was employed to integrate the results. When applicable, a meta-analysis was conducted using a random-effect model. RESULTS Of the 16 studies included, ten investigated periodontal pathobionts and six were microbiome-wide association studies. Samples from the brain, serum, and oral cavity were tested. We found over a ten-fold and six-fold increased risk of AD when there were oral bacteria (OR = 10.68 95% CI: 4.48-25.43; p < 0.00001, I2 = 0%) and Porphyromonas gingivalis (OR = 6.84 95% CI: 2.70-17.31; p < 0.0001, I2 = 0%) respectively in the brain. While AD patients exhibited lower alpha diversity of oral microbiota than healthy controls, the findings of bacterial communities were inconsistent among studies. The best evidence synthesis suggested a moderate level of evidence for an overall association between oral bacteria and AD and for oral bacteria being a risk factor for AD. CONCLUSION Current evidence moderately supports the association between oral bacteria and AD, while the association was strong when oral bacteria were detectable in the brain. Further evidence is needed to clarify the interrelationship between both individual species and bacterial communities and the development of AD.
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Affiliation(s)
- Sixin Liu
- School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Stuart G Dashper
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Australia
| | - Rui Zhao
- Department of Stomatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
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36
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Pisani F, Pisani V, Arcangeli F, Harding A, Singhrao SK. Locus Coeruleus Dysfunction and Trigeminal Mesencephalic Nucleus Degeneration: A Cue for Periodontal Infection Mediated Damage in Alzheimer's Disease? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:1007. [PMID: 36673763 PMCID: PMC9858796 DOI: 10.3390/ijerph20021007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/30/2022] [Accepted: 01/01/2023] [Indexed: 06/12/2023]
Abstract
Alzheimer's disease (AD) is a leading neurodegenerative disease with deteriorating cognition as its main clinical sign. In addition to the clinical history, it is characterized by the presence of two neuropathological hallmark lesions; amyloid-beta (Aβ) and neurofibrillary tangles (NFTs), identified in the brain at post-mortem in specific anatomical areas. Recently, it was discovered that NFTs occur initially in the subcortical nuclei, such as the locus coeruleus in the pons, and are said to spread from there to the cerebral cortices and the hippocampus. This contrasts with the prior acceptance of their neuropathology in the enthorinal cortex and the hippocampus. The Braak staging system places the accumulation of phosphorylated tau (p-tau) binding to NFTs in the locus coeruleus and other subcortical nuclei to precede stages I-IV. The locus coeruleus plays diverse psychological and physiological roles within the human body including rapid eye movement sleep disorder, schizophrenia, anxiety, and depression, regulation of sleep-wake cycles, attention, memory, mood, and behavior, which correlates with AD clinical behavior. In addition, the locus coeruleus regulates cardiovascular, respiratory, and gastrointestinal activities, which have only recently been associated with AD by modern day research enabling the wider understanding of AD development via comorbidities and microbial dysbiosis. The focus of this narrative review is to explore the modes of neurodegeneration taking place in the locus coeruleus during the natural aging process of the trigeminal nerve connections from the teeth and microbial dysbiosis, and to postulate a pathogenetic mechanism due to periodontal damage and/or infection focused on Treponema denticola.
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Affiliation(s)
- Flavio Pisani
- Programme Lead, MSc/MClinDent in Clinical Periodontology, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - Valerio Pisani
- I.R.C.C.S. “Santa Lucia” Foundation, Neurology and Neurorehabilitation Unit, Via Ardeatina, 306, 00179 Rome, Italy
| | - Francesca Arcangeli
- Azienda Sanitaria Locale ASLRM1, Nuovo Regina Margherita Hospital, Geriatric Department-Advanced Centre for Dementia and Cognitive Disorders, Via Emilio Morosini, 30, 00153 Rome, Italy
| | - Alice Harding
- Dementia and Neurodegenerative Disease Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - Sim K. Singhrao
- Dementia and Neurodegenerative Disease Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
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Wei T, Du Y, Hou T, Zhai C, Li Y, Xiao W, Liu K. Association between adverse oral conditions and cognitive impairment: A literature review. Front Public Health 2023; 11:1147026. [PMID: 37089515 PMCID: PMC10117837 DOI: 10.3389/fpubh.2023.1147026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/02/2023] [Indexed: 04/25/2023] Open
Abstract
Oral environment deterioration results from a lack of self-cleaning ability in patients with cognitive dysfunction but is also a risk factor for cognitive dysfunction. Adverse oral conditions can be alleviated and improved through a self-management and medical examination. In this review, the epidemiological evidence of previous studies is integrated to highlight the relationship between periodontitis, tooth loss, oral flora, oral dysfunction and cognitive dysfunction, emphasizing the importance of oral health for cognition. The results show that poor oral condition is associated with cognitive impairment. Although many previous studies have been conducted, there is a lack of higher-level research evidence, different judgment criteria, and conflicting research results. There is a bidirectional relationship between oral health and cognitive dysfunction. A comprehensive analysis of the relationship between oral health and cognitive dysfunction that explores the relationship and takes measures to prevent cognitive dysfunction and control the progression of such diseases is warranted in the future.
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Affiliation(s)
- Tianhao Wei
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Yifeng Du
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Department of Neurology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Tingting Hou
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Department of Neurology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Chunjuan Zhai
- Department of Cardiology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Yuqi Li
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Wei Xiao
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Department of Neurology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Keke Liu
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Department of Neurology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
- Department of Infection Control, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
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Wang M, Yan LY, Qiao CY, Zheng CC, Niu CG, Huang ZW, Pan YH. Ecological shifts of salivary microbiota associated with metabolic-associated fatty liver disease. Front Cell Infect Microbiol 2023; 13:1131255. [PMID: 36864882 PMCID: PMC9971218 DOI: 10.3389/fcimb.2023.1131255] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023] Open
Abstract
Introduction Metabolic-associated fatty liver disease (MAFLD) is the most common chronic liver disease related to metabolic syndrome. However, ecological shifts in the saliva microbiome in patients with MAFLD remain unknown. This study aimed to investigate the changes to the salivary microbial community in patients with MAFLD and explore the potential function of microbiota. Methods Salivary microbiomes from ten MAFLD patients and ten healthy participants were analyzed by 16S rRNA amplicon sequencing and bioinformatics analysis. Body composition, plasma enzymes, hormones, and blood lipid profiles were assessed with physical examinations and laboratory tests. Results The salivary microbiome of MAFLD patients was characterized by increased α-diversity and distinct β-diversity clustering compared with control subjects. Linear discriminant analysis effect size analysis showed a total of 44 taxa significantly differed between the two groups. Genera Neisseria, Filifactor, and Capnocytophaga were identified as differentially enriched genera for comparison of the two groups. Co-occurrence networks suggested that the salivary microbiota from MAFLD patients exhibited more intricate and robust interrelationships. The diagnostic model based on the salivary microbiome achieved a good diagnostic power with an area under the curve of 0.82(95% CI: 0.61-1). Redundancy analysis and spearman correlation analysis revealed that clinical variables related to insulin resistance and obesity were strongly associated with the microbial community. Metagenomic predictions based on Phylogenetic Investigation of Communities by Reconstruction of Unobserved States revealed that pathways related to metabolism were more prevalent in the two groups. Conclusions Patients with MAFLD manifested ecological shifts in the salivary microbiome, and the saliva microbiome-based diagnostic model provides a promising approach for auxiliary MAFLD diagnosis.
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Affiliation(s)
- Min Wang
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
- Department of Endodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Li-Ya Yan
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Cai-Yun Qiao
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Chu-Chu Zheng
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Chen-Guang Niu
- Department of Endodontics, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Clinical Research Center for Oral Diseases, National Center for Stomatology, Shanghai, China
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Zheng-Wei Huang
- Department of Endodontics, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Clinical Research Center for Oral Diseases, National Center for Stomatology, Shanghai, China
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
- *Correspondence: Zheng-Wei Huang, ; Yi-Huai Pan,
| | - Yi-Huai Pan
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
- Department of Endodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Zheng-Wei Huang, ; Yi-Huai Pan,
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Emery DC, Davies M, Cerajewska TL, Taylor J, Hazell M, Paterson A, Allen-Birt SJ, West NX. High resolution 16S rRNA gene Next Generation Sequencing study of brain areas associated with Alzheimer's and Parkinson's disease. Front Aging Neurosci 2022; 14:1026260. [PMID: 36570533 PMCID: PMC9780557 DOI: 10.3389/fnagi.2022.1026260] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/02/2022] [Indexed: 12/13/2022] Open
Abstract
Introduction Alzheimer's (AD) and Parkinson's disease (PD) are neurodegenerative conditions characterized by incremental deposition of β-amyloid (Aβ) and α-synuclein in AD and PD brain, respectively, in relatively conserved patterns. Both are associated with neuroinflammation, with a proposed microbial component for disease initiation and/or progression. Notably, Aβ and α-synuclein have been shown to possess antimicrobial properties. There is evidence for bacterial presence within the brain, including the oral pathobiont Porphyromonas gingivalis, with cognitive impairment and brain pathology being linked to periodontal (gum) disease and gut dysbiosis. Methods Here, we use high resolution 16S rRNA PCR-based Next Generation Sequencing (16SNGS) to characterize bacterial composition in brain areas associated with the early, intermediate and late-stage of the diseases. Results and discussion This study reveals the widespread presence of bacteria in areas of the brain associated with AD and PD pathology, with distinctly different bacterial profiles in blood and brain. Brain area profiles were overall somewhat similar, predominantly oral, with some bacteria subgingival and oronasal in origin, and relatively comparable profiles in AD and PD brain. However, brain areas associated with early disease development, such as the locus coeruleus, were substantially different in bacterial DNA content compared to areas affected later in disease etiology.
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Affiliation(s)
| | | | | | | | - Mae Hazell
- Translational Health Sciences, Learning and Research, Bristol Medical School, Southmead Hospital, Bristol, United Kingdom
| | - Alex Paterson
- School of Biological Sciences, University of Bristol Genomics Facility, Bristol, United Kingdom
| | - Shelley J. Allen-Birt
- Translational Health Sciences, Learning and Research, Bristol Medical School, Southmead Hospital, Bristol, United Kingdom
| | - Nicola X. West
- Bristol Dental School, Bristol, United Kingdom,*Correspondence: Nicola X. West,
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Dziedzic A. Is Periodontitis Associated with Age-Related Cognitive Impairment? The Systematic Review, Confounders Assessment and Meta-Analysis of Clinical Studies. Int J Mol Sci 2022; 23:15320. [PMID: 36499656 PMCID: PMC9739281 DOI: 10.3390/ijms232315320] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/27/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
It has been suggested that molecular pathological mechanisms responsible for periodontitis can be linked with biochemical alterations in neurodegenerative disorders. Hypothetically, chronic systemic inflammation as a response to periodontitis plays a role in the etiology of cognitive impairment. This study aimed to determine whether periodontitis (PDS) is a risk factor for age-related cognitive impairment (ACI) based on evidence of clinical studies. A comprehensive, structured systematic review of existing data adhering to the Preferred Reporting Items for Systematic Review and Meta Analyses (PRISMA) guidelines was carried out. Five electronic databases, PubMed, Embase, Scopus, Web of Science, and Cochrane, were searched for key terms published in peer-reviewed journals until January 2021. The Newcastle-Ottawa scale was used to assess the quality of studies and risk of bias. The primary and residual confounders were explored and evaluated. A meta-analysis synthesizing quantitative data was carried out using a random-effects model. Seventeen clinical studies were identified, including 14 cohort, one cross-sectional, and two case-control studies. Study samples ranged from 85 to 262,349 subjects, with follow-up between 2 and 32 years, and age above 45 years, except for two studies. The findings of studies suggesting the PDS-ACI relationship revealed substantial differences in design and methods. A noticeable variation related to the treatment of confounders was observed. Quality assessment unveiled a moderate quality of evidence and risk of bias. The subgroups meta-analysis and pooled sensitivity analysis of results from seven eligible studies demonstrated overall that the presence of PDS is associated with an increased risk of incidence of cognitive impairment (OR = 1.36, 95% CI 1.03-1.79), particularly dementia (OR = 1.39, 95% CI 1.02-1.88) and Alzheimer's disease (OR = 1.03 95% CI 0.98-1.07)). However, a considerable heterogeneity of synthesized data (I2 = 96%) and potential publication bias might affect obtained results. While there is a moderate statistical association between periodontitis and dementia, as well as Alzheimer's disease, the risk of bias in the evidence prevents conclusions being drawn about the role of periodontitis as a risk factor for age-related cognitive impairment.
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Affiliation(s)
- Arkadiusz Dziedzic
- Department of Conservative Dentistry with Endodontics, Medical University of Silesia, 40-055 Katowice, Poland
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Application of Fluorescence In Situ Hybridization (FISH) in Oral Microbial Detection. Pathogens 2022; 11:pathogens11121450. [PMID: 36558784 PMCID: PMC9788346 DOI: 10.3390/pathogens11121450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/26/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022] Open
Abstract
Varieties of microorganisms reside in the oral cavity contributing to the occurrence and development of microbes associated with oral diseases; however, the distribution and in situ abundance in the biofilm are still unclear. In order to promote the understanding of the ecosystem of oral microbiota and the diagnosis of oral diseases, it is necessary to monitor and compare the oral microorganisms from different niches of the oral cavity in situ. The fluorescence in situ hybridization (FISH) has proven to be a powerful tool for representing the status of oral microorganisms in the oral cavity. FISH is one of the most routinely used cytochemical techniques for genetic detection, identification, and localization by a fluorescently labeled nucleic acid probe, which can hybridize with targeted nucleic acid sequences. It has the advantages of rapidity, safety, high sensitivity, and specificity. FISH allows the identification and quantification of different oral microorganisms simultaneously. It can also visualize microorganisms by combining with other molecular biology technologies to represent the distribution of each microbial community in the oral biofilm. In this review, we summarized and discussed the development of FISH technology and the application of FISH in oral disease diagnosis and oral ecosystem research, highlighted its advantages in oral microbiology, listed the existing problems, and provided suggestions for future development..
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Turnbull N, Cherdsakul P, Chanaboon S, Hughes D, Tudpor K. Tooth Loss, Cognitive Impairment and Fall Risk: A Cross-Sectional Study of Older Adults in Rural Thailand. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16015. [PMID: 36498085 PMCID: PMC9735973 DOI: 10.3390/ijerph192316015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/24/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Tooth loss is associated with both cognitive impairment and fall risk. However, the relationships between these variables are complex and bidirectional. Observed associations have been reported in separate studies but data on rural-dwelling older adults remain sparse. This cross-sectional study investigated socioeconomic and dental factors affecting cognitive functions, and the association between tooth loss, cognitive functioning, and fall risk. Two hundred and thirty-one rural-dwelling older adults (60−74 years old) were recruited from a single Dental Service Unit. Cognitive function and fall risk were assessed with the Mini-Mental State Examination and the Morse Fall Scale, respectively. Oral examinations were performed by a dentist using the Community Periodontal Index of Treatment Needs form. 38.1%, had >16 tooth loss. Socioeconomic data and health status were obtained from a questionnaire and interviews. Age, Activities of Daily Living (ADL) score, and the number of teeth lost was significantly associated with impaired cognitive function. Chi-square analysis showed that cognitive function was also associated with fall risk. Past research suggests that much cognitive impairment and fall risk is induced by tooth loss. Service planners need to be aware of the complex bidirectional relationships between these variables and give higher priority to dental services that can improve the general health status and social functioning of older rural adults.
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Affiliation(s)
- Niruwan Turnbull
- Faculty of Public Health, Mahasarakham University, Maha Sarakham 44150, Thailand
- Public Health and Environmental Policy in Southeast Asia Research Unit (PHEP-SEA), Mahasarakham University, Maha Sarakham 44150, Thailand
| | | | - Sutin Chanaboon
- Sirindhorn College of Public Health Khon Kaen, Khon Kaen 40000, Thailand
| | - David Hughes
- Faculty of Medicine, Health & Life Science, Swansea University, Swansea SA2 8PP, UK
| | - Kukiat Tudpor
- Faculty of Public Health, Mahasarakham University, Maha Sarakham 44150, Thailand
- Public Health and Environmental Policy in Southeast Asia Research Unit (PHEP-SEA), Mahasarakham University, Maha Sarakham 44150, Thailand
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Vojtechova I, Machacek T, Kristofikova Z, Stuchlik A, Petrasek T. Infectious origin of Alzheimer’s disease: Amyloid beta as a component of brain antimicrobial immunity. PLoS Pathog 2022; 18:e1010929. [PMCID: PMC9671327 DOI: 10.1371/journal.ppat.1010929] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The amyloid cascade hypothesis, focusing on pathological proteins aggregation, has so far failed to uncover the root cause of Alzheimer’s disease (AD), or to provide an effective therapy. This traditional paradigm essentially explains a mechanism involved in the development of sporadic AD rather than its cause. The failure of an overwhelming majority of clinical studies (99.6%) demonstrates that a breakthrough in therapy would be difficult if not impossible without understanding the etiology of AD. It becomes more and more apparent that the AD pathology might originate from brain infection. In this review, we discuss a potential role of bacteria, viruses, fungi, and eukaryotic parasites as triggers of AD pathology. We show evidence from the current literature that amyloid beta, traditionally viewed as pathological, actually acts as an antimicrobial peptide, protecting the brain against pathogens. However, in case of a prolonged or excessive activation of a senescent immune system, amyloid beta accumulation and aggregation becomes damaging and supports runaway neurodegenerative processes in AD. This is paralleled by the recent study by Alam and colleagues (2022) who showed that alpha-synuclein, the protein accumulating in synucleinopathies, also plays a critical physiological role in immune reactions and inflammation, showing an unforeseen link between the 2 unrelated classes of neurodegenerative disorders. The multiplication of the amyloid precursor protein gene, recently described by Lee and collegues (2018), and possible reactivation of human endogenous retroviruses by pathogens fits well into the same picture. We discuss these new findings from the viewpoint of the infection hypothesis of AD and offer suggestions for future research. More than a century after its discovery, Alzheimer’s disease (AD) remains incurable and mysterious. The dominant hypothesis of amyloid cascade has succeeded in explaining the key pathological mechanism, but not its trigger. Amyloid beta has been traditionally considered a pathological peptide, and its physiological functions remain poorly known. These knowledge gaps have contributed to repeated failures of clinical studies. The emerging infectious hypothesis of AD considers central nervous system (CNS) infection the primary trigger of sporadic AD. A closely connected hypothesis claims that amyloid beta is an antimicrobial peptide. In this review, we discuss the available evidence for the involvement of infections in AD, coming from epidemiological studies, post mortem analyses of brain tissue, and experiments in vitro and in vivo. We argue there is no unique “Alzheimer’s germ,” instead, AD is a general reaction of the CNS to chronic infections, in the milieu of an aged immune system. The pathology may become self-sustained even without continuous presence of microbes in the brain. Importantly, the infectious hypothesis leads to testable predictions. Targeting amyloid beta should be ineffective, unless the triggering pathogen and inflammatory response are addressed as well. Meticulous control of selected infections might be the best near-term strategy for AD prevention.
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Affiliation(s)
- Iveta Vojtechova
- National Institute of Mental Health, Klecany, Czech Republic
- Laboratory of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- * E-mail: , (IV); , (TP)
| | - Tomas Machacek
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | | | - Ales Stuchlik
- National Institute of Mental Health, Klecany, Czech Republic
- Laboratory of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomas Petrasek
- National Institute of Mental Health, Klecany, Czech Republic
- Laboratory of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- * E-mail: , (IV); , (TP)
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Ablinger I, Dressel K, Rott T, Lauer AA, Tiemann M, Batista JP, Taddey T, Grimm HS, Grimm MOW. Interdisciplinary Approaches to Deal with Alzheimer's Disease-From Bench to Bedside: What Feasible Options Do Already Exist Today? Biomedicines 2022; 10:2922. [PMID: 36428494 PMCID: PMC9687885 DOI: 10.3390/biomedicines10112922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/03/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Alzheimer's disease is one of the most common neurodegenerative diseases in the western population. The incidence of this disease increases with age. Rising life expectancy and the resulting increase in the ratio of elderly in the population are likely to exacerbate socioeconomic problems. Alzheimer's disease is a multifactorial disease. In addition to amyloidogenic processing leading to plaques, and tau pathology, but also other molecular causes such as oxidative stress or inflammation play a crucial role. We summarize the molecular mechanisms leading to Alzheimer's disease and which potential interventions are known to interfere with these mechanisms, focusing on nutritional approaches and physical activity but also the beneficial effects of cognition-oriented treatments with a focus on language and communication. Interestingly, recent findings also suggest a causal link between oral conditions, such as periodontitis or edentulism, and Alzheimer's disease, raising the question of whether dental intervention in Alzheimer's patients can be beneficial as well. Unfortunately, all previous single-domain interventions have been shown to have limited benefit to patients. However, the latest studies indicate that combining these efforts into multidomain approaches may have increased preventive or therapeutic potential. Therefore, as another emphasis in this review, we provide an overview of current literature dealing with studies combining the above-mentioned approaches and discuss potential advantages compared to monotherapies. Considering current literature and intervention options, we also propose a multidomain interdisciplinary approach for the treatment of Alzheimer's disease patients that synergistically links the individual approaches. In conclusion, this review highlights the need to combine different approaches in an interdisciplinary manner, to address the future challenges of Alzheimer's disease.
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Affiliation(s)
- Irene Ablinger
- Speech and Language Therapy, Campus Bonn, SRH University of Applied Health Sciences, 53111 Bonn, Germany
| | - Katharina Dressel
- Speech and Language Therapy, Campus Düsseldorf, SRH University of Applied Health Sciences, 40210 Düsseldorf, Germany
| | - Thea Rott
- Interdisciplinary Periodontology and Prevention, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
| | - Anna Andrea Lauer
- Nutrition Therapy and Counseling, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
- Experimental Neurology, Saarland University, 66424 Homburg, Germany
| | - Michael Tiemann
- Sport Science, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
| | - João Pedro Batista
- Sport Science and Physiotherapy, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
| | - Tim Taddey
- Physiotherapy, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
| | - Heike Sabine Grimm
- Nutrition Therapy and Counseling, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
- Experimental Neurology, Saarland University, 66424 Homburg, Germany
| | - Marcus Otto Walter Grimm
- Nutrition Therapy and Counseling, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
- Experimental Neurology, Saarland University, 66424 Homburg, Germany
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Li X, Kiprowska M, Kansara T, Kansara P, Li P. Neuroinflammation: A Distal Consequence of Periodontitis. J Dent Res 2022; 101:1441-1449. [PMID: 35708472 PMCID: PMC9608094 DOI: 10.1177/00220345221102084] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Periodontitis, a chronic, inflammatory disease, induces systemic inflammation and contributes to the development of neurodegenerative diseases. The precise etiology of the most common neurodegenerative disorders, such as sporadic Alzheimer's, Parkinson's diseases and multiple sclerosis (AD, PD, and MS, respectively), remains to be revealed. Chronic neuroinflammation is a well-recognized component of these disorders, and evidence suggests that systemic inflammation is a possible stimulus for neuroinflammation development. Systemic inflammation can lead to deleterious consequences on the brain if the inflammation is sufficiently severe or if the brain shows vulnerabilities due to genetic predisposition, aging, or neurodegenerative diseases. It has been proposed that periodontal disease can initiate or contribute to the AD pathogenesis through multiple pathways, including key periodontal pathogens. Dysbiotic oral bacteria can release bacterial products into the bloodstream and eventually cross the brain-blood barrier; these bacteria can also cause alterations to gut microbiota that enhance inflammation and potentially affect brain function via the gut-brain axis. The trigeminal nerve has been suggested as another route for connecting oral bacterial products to the brain. PD and MS are often preceded by gastrointestinal symptoms or aberrant gut microbiome composition, and alterations in the enteric nervous system accompany the disease. Clinical evidence has suggested that patients with periodontitis are at a higher risk of developing PD and MS. This nexus among the brain, periodontal disease, and systemic inflammation heralds new ways in which microglial cells, the main innate immune cells, and astrocytes, the crucial regulators of innate and adaptive immune responses in the brain, contribute to brain pathology. Currently, the lack of understanding of the pathogenesis of neurodegeneration is hindering treatment development. However, we may prevent this pathogenesis by tackling one of its possible contributors (periodontitis) for systemic inflammation through simple preventive oral hygiene measures.
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Affiliation(s)
- X. Li
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
- Department of Urology, New York University Grossman School of Medicine, New York, NY, USA
- Perlmutter Cancer Institute, New York University Langone Medical Center, New York, NY, USA
| | - M. Kiprowska
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
| | - T. Kansara
- Cleveland Clinic- Union hospital, Dover, OH, USA
| | - P. Kansara
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
| | - P. Li
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
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Nemergut M, Batkova T, Vigasova D, Bartos M, Hlozankova M, Schenkmayerova A, Liskova B, Sheardova K, Vyhnalek M, Hort J, Laczó J, Kovacova I, Sitina M, Matej R, Jancalek R, Marek M, Damborsky J. Increased occurrence of Treponema spp. and double-species infections in patients with Alzheimer's disease. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 844:157114. [PMID: 35787909 DOI: 10.1016/j.scitotenv.2022.157114] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 06/25/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
Although the link between microbial infections and Alzheimer's disease (AD) has been demonstrated in multiple studies, the involvement of pathogens in the development of AD remains unclear. Here, we investigated the frequency of the 10 most commonly cited viral (HSV-1, EBV, HHV-6, HHV-7, and CMV) and bacterial (Chlamydia pneumoniae, Helicobacter pylori, Borrelia burgdorferi, Porphyromonas gingivalis, and Treponema spp.) pathogens in serum, cerebrospinal fluid (CSF) and brain tissues of AD patients. We have used an in-house multiplex PCR kit for simultaneous detection of five bacterial and five viral pathogens in serum and CSF samples from 50 AD patients and 53 healthy controls (CTRL). We observed a significantly higher frequency rate of AD patients who tested positive for Treponema spp. compared to controls (AD: 62.2 %; CTRL: 30.3 %; p-value = 0.007). Furthermore, we confirmed a significantly higher occurrence of cases with two or more simultaneous infections in AD patients compared to controls (AD: 24 %; CTRL 7.5 %; p-value = 0.029). The studied pathogens were detected with comparable frequency in serum and CSF. In contrast, Borrelia burgdorferi, human herpesvirus 7, and human cytomegalovirus were not detected in any of the studied samples. This study provides further evidence of the association between microbial infections and AD and shows that paralleled analysis of multiple sample specimens provides complementary information and is advisable for future studies.
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Affiliation(s)
- Michal Nemergut
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Brno, Czech Republic
| | - Tereza Batkova
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Department of Neurology, Masaryk University, St. Anne's University Hospital Brno, Brno, Czech Republic; BioVendor R&D, Brno, Czech Republic
| | - Dana Vigasova
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Brno, Czech Republic
| | | | | | - Andrea Schenkmayerova
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Brno, Czech Republic
| | - Barbora Liskova
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Brno, Czech Republic
| | - Katerina Sheardova
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Department of Neurology, Masaryk University, St. Anne's University Hospital Brno, Brno, Czech Republic
| | - Martin Vyhnalek
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Jakub Hort
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Jan Laczó
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Department of Neurology, Charles University, Second Faculty of Medicine and Motol University Hospital, Prague, Czech Republic
| | - Ingrid Kovacova
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic
| | - Michal Sitina
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic
| | - Radoslav Matej
- Department of Pathology and Molecular Medicine, Third Faculty of Medicine, Charles University and Thomayer University Hospital, Prague, Czech Republic
| | - Radim Jancalek
- Department of Neurosurgery, St. Anne's University Hospital Brno, Brno, Czech Republic and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Martin Marek
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Brno, Czech Republic
| | - Jiri Damborsky
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Masaryk University, Brno, Czech Republic.
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Treponema denticola Induces Neuronal Apoptosis by Promoting Amyloid-β Accumulation in Mice. Pathogens 2022; 11:pathogens11101150. [PMID: 36297207 PMCID: PMC9610539 DOI: 10.3390/pathogens11101150] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Neuronal apoptosis is a major contributor to Alzheimer's disease (AD). Periodontitis is a significant risk factor for AD. The periodontal pathogens Porphyromonas gingivalis and Treponema denticola have been shown to initiate the hallmark pathologies and behavioral symptoms of AD. Studies have found that T. denticola infection induced Tau hyperphosphorylation and amyloid β accumulation in the hippocampi of mice. Aβ accumulation is closely associated with neuronal apoptosis. However, the roles of T. denticola in neuronal apoptosis remain unclear and its roles in AD pathology need further study. Objective: This study aimed to investigate whether oral infection with T. denticola induced alveolar bone loss and neuronal apoptosis in mice. Methods: C57BL/6 mice were orally administered with T. denticola, Micro-CT was employed to assess the alveolar bone resorption. Western blotting, quantitative PCR, and TUNEL staining were utilized to detect the apoptosis-associated changes in mouse hippocampi. N2a were co-cultured with T. denticola to verify in vivo results. Results: Mice infected with T. denticola exhibited more alveolar bone loss compared with the control mice. T. denticola oral infection induced neuronal apoptosis in hippocampi of mice. Consistent results of the apoptosis-associated protein expression were observed in N2a cells treated with T. denticola and Aβ1-42 in vitro. However, the Aβ inhibitor reversed these results, suggesting that Aβ1-42 mediates T. denticola infection-induced neuronal apoptosis. Conclusions: This study found that oral infected T. denticola caused alveolar bone loss, and induced neuronal apoptosis by promoting Aβ accumulation in mice, providing evidence for the link between periodontitis and AD.
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Implications of Microorganisms in Alzheimer's Disease. Curr Issues Mol Biol 2022; 44:4584-4615. [PMID: 36286029 PMCID: PMC9600878 DOI: 10.3390/cimb44100314] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/23/2022] [Accepted: 09/28/2022] [Indexed: 11/20/2022] Open
Abstract
Alzheimer’s disease (AD) is a deadly brain degenerative disorder that leads to brain shrinkage and dementia. AD is manifested with hyperphosphorylated tau protein levels and amyloid beta (Aβ) peptide buildup in the hippocampus and cortex regions of the brain. The nervous tissue of AD patients also contains fungal proteins and DNA which are linked to bacterial infections, suggesting that polymicrobial infections also occur in the brains of those with AD. Both immunohistochemistry and next-generation sequencing (NGS) techniques were employed to assess fungal and bacterial infections in the brain tissue of AD patients and non-AD controls, with the most prevalent fungus genera detected in AD patients being Alternaria, Botrytis, Candida, and Malassezia. Interestingly, Fusarium was the most common genus detected in the control group. Both AD patients and controls were also detectable for Proteobacteria, followed by Firmicutes, Actinobacteria, and Bacteroides for bacterial infection. At the family level, Burkholderiaceae and Staphylococcaceae exhibited higher levels in the brains of those with AD than the brains of the control group. Accordingly, there is thought to be a viscous cycle of uncontrolled neuroinflammation and neurodegeneration in the brain, caused by agents such as the herpes simplex virus type 1 (HSV1), Chlamydophilapneumonia, and Spirochetes, and the presence of apolipoprotein E4 (APOE4), which is associated with an increased proinflammatory response in the immune system. Systemic proinflammatory cytokines are produced by microorganisms such as Cytomegalovirus, Helicobacter pylori, and those related to periodontal infections. These can then cross the blood–brain barrier (BBB) and lead to the onset of dementia. Here, we reviewed the relationship between the etiology of AD and microorganisms (such as bacterial pathogens, Herpesviridae viruses, and periodontal pathogens) according to the evidence available to understand the pathogenesis of AD. These findings might guide a targeted anti-inflammatory therapeutic approach to AD.
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Kim SR, Son M, Kim YR, Kang HK. Risk of dementia according to the severity of chronic periodontitis in Korea: a nationwide retrospective cohort study. Epidemiol Health 2022; 44:e2022077. [PMID: 36177981 PMCID: PMC9849849 DOI: 10.4178/epih.e2022077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/21/2022] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVES We investigated the risk of dementia in older adults with chronic periodontitis according to the severity of periodontitis. METHODS Data on patients with chronic periodontitis were extracted from the National Health Insurance Service-Senior cohort database from 2002 to 2014. Among 52,728 subjects eligible for inclusion, 11,953 subjects had newly diagnosed mild chronic periodontitis (MCP), and 40,775 subjects had newly diagnosed severe chronic periodontitis (SCP). Two 1:1 propensity score matched cohorts were created with 8,624 patients each in the MCP and SCP groups. To analyze the risk of dementia, a Cox proportional-hazard model was used to calculate hazard ratios with 95% confidence intervals (CIs). RESULTS In the Kaplan-Meier curve, the disease-free probability was significantly lower in the SCP group than in the MCP group (p for log-rank=0.001). In the multivariable-adjusted model, the HR for the occurrence of dementia in the SCP group compared to the MCP group was 1.15 (95% CI, 1.04 to 1.27; p=0.009). A subgroup analysis revealed a significant association between dementia and the severity of periodontitis, especially in subjects who were male, aged ≥70 years, and had comorbidities. CONCLUSIONS Reducing the severity of chronic periodontitis can help to reduce the risk of dementia. Therefore, it is necessary to aggressively conduct early dementia-prevention programs for males under the age of 70 that include dental health to prevent the progression of periodontitis from mild to severe.
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Affiliation(s)
- Seon-Rye Kim
- Department of Healthcare Management, Youngsan University, Yangsan, Korea
| | - Minkook Son
- Department of Physiology, Dong-A University College of Medicine, Busan, Korea
| | - Yu-Rin Kim
- Department of Dental Hygiene, Silla University, Busan, Korea,Correspondence: Yu-Rin Kim Department of Dental Hygiene, Silla University, 140 Baegyang-daero 700beon-gil, Sasang-gu, Busan 46958, Korea E-mail:
| | - Hyun-Kyung Kang
- Department of Dental Hygiene, Silla University, Busan, Korea,Co-correspondence: Hyun-Kyung Kang Department of Dental Hygiene, Silla University, 140 Baegyang-daero 700beon-gil, Sasang-gu, Busan 46958, Korea E-mail:
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Chen L, Wang B, Liu J, Wu X, Xu X, Cao H, Ji X, Zhang P, Li X, Hou Z, Li H. Different oral and gut microbial profiles in those with Alzheimer's disease consuming anti-inflammatory diets. Front Nutr 2022; 9:974694. [PMID: 36185672 PMCID: PMC9521405 DOI: 10.3389/fnut.2022.974694] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/15/2022] [Indexed: 12/06/2022] Open
Abstract
The number of people living with Alzheimer's disease (AD) is increasing alongside with aging of the population. Systemic chronic inflammation and microbial imbalance may play an important role in the pathogenesis of AD. Inflammatory diets regulate both the host microbiomes and inflammatory status. This study aimed to explore the impact of inflammatory diets on oral-gut microbes in patients with AD and the relationship between microbes and markers of systemic inflammation. The dietary inflammatory properties and the oral and gut microorganisms were analyzed using the dietary inflammatory index (DII) and 16S RNA in 60 patients with AD. The α-diversity was not related to the DII (p > 0.05), whereas the β-diversity was different in the oral microbiomes (R2 = 0.061, p = 0.013). In the most anti-inflammatory diet group, Prevotella and Olsenella were more abundant in oral microbiomes and Alistipes, Ruminococcus, Odoribacter, and unclassified Firmicutes were in the gut microbiomes (p < 0.05). Specific oral and gut genera were associated with interleukin-6 (IL)-6, complement 3 (C3), high-sensitivity C-reactive protein (hs-CRP), IL-1β, IL-4, IL-10, IL-12, and tumor necrosis factor-α (TNF-α) (p < 0.05). In conclusion, anti-inflammatory diets seem to be associated with increased abundance of beneficial microbes, and specific oral and gut microbial composition was associated with inflammatory markers.
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Affiliation(s)
- Lili Chen
- Shengli Clinical Medical College of Fujian Medical University, Fuzhou, China
- The School of Nursing, Fujian Medical University, Fuzhou, China
- Fujian Provincial Hospital, Fuzhou, China
- Lili Chen
| | - Bixia Wang
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Jinxiu Liu
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Xiaoqi Wu
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Xinhua Xu
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Huizhen Cao
- Shengli Clinical Medical College of Fujian Medical University, Fuzhou, China
- Fujian Provincial Hospital, Fuzhou, China
| | - Xinli Ji
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Ping Zhang
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Xiuli Li
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Zhaoyi Hou
- The School of Nursing, Fujian Medical University, Fuzhou, China
| | - Hong Li
- Shengli Clinical Medical College of Fujian Medical University, Fuzhou, China
- The School of Nursing, Fujian Medical University, Fuzhou, China
- Fujian Provincial Hospital, Fuzhou, China
- *Correspondence: Hong Li
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