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Nie R, Wu Z, Ni J, Zeng F, Yu W, Zhang Y, Kadowaki T, Kashiwazaki H, Teeling JL, Zhou Y. Porphyromonas gingivalis Infection Induces Amyloid-β Accumulation in Monocytes/Macrophages. J Alzheimers Dis 2019; 72:479-494. [DOI: 10.3233/jad-190298] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Ran Nie
- Department of Dental Implantology, School and Hospital of Stomatology, Jilin University, Changchun, China
| | - Zhou Wu
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, Japan
- OBT Research Center, Faculty of Dental Sciences, Kyushu University, Fukuoka, Japan
| | - Junjun Ni
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, Japan
| | - Fan Zeng
- Department of Aging Science and Pharmacology, Faculty of Dental Sciences, Kyushu University, Fukuoka, Japan
| | - Weixian Yu
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Jilin University, Changchun, China
| | - Yufeng Zhang
- Gerontal Department of Stomatology, School and Hospital of Stomatology, Jilin University, Changchun, China
| | - Tomoko Kadowaki
- Division of Frontier Life Science, Department of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Haruhiko Kashiwazaki
- Section of Geriatric Dentistry and Perioperative Medicine in Dentistry, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Sciences, Kyushu University, Fukuoka, Japan
| | - Jessica L. Teeling
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom
| | - Yanmin Zhou
- Department of Dental Implantology, School and Hospital of Stomatology, Jilin University, Changchun, China
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202
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Olsen I, Singhrao SK. Is there a link between genetic defects in the complement cascade and Porphyromonas gingivalis in Alzheimer's disease? J Oral Microbiol 2019; 12:1676486. [PMID: 31893014 PMCID: PMC6818111 DOI: 10.1080/20002297.2019.1676486] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 09/17/2019] [Indexed: 12/18/2022] Open
Abstract
Defects, as determined by Genome-Wide Association Studies (GWAS), in the complement cascade of innate immunity have been suggested to play a key role in Alzheimer's disease (AD). These defective genes encode sub-component 1s (C1s), complement receptor 1, complement component 9, and clusterin, a fluid-phase regulatory protein. A dysregulated complement cascade has been shown to relate to cell activation, defective complement mediated clearance and possible cognitive decline in AD patients. Porphyromonas gingivalis, a putative keystone pathogen of periodontal disease, has been reported to be associated with human AD. The inflammatory burden following experimental oral infection in mice and putative entry of this bacterium into the brain appears to drive the formation of amyloid-beta plaques and neurofibrillary tangles with loss of cognition. P. gingivalis is a master of immune subversion in this inflammatory cascade and may establish microbial dysbiosis where it is located. Here we discuss if P. gingivalis may enhance the detrimental effects of the defective GWAS complement cascade protein genes.
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Affiliation(s)
- Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Sim K Singhrao
- Dementia and Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
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203
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Systemic inflammation linking chronic periodontitis to cognitive decline. Brain Behav Immun 2019; 81:63-73. [PMID: 31279681 DOI: 10.1016/j.bbi.2019.07.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/03/2019] [Accepted: 07/03/2019] [Indexed: 12/25/2022] Open
Abstract
Persistent inflammation in the systemic immune system can impose detrimental effects on the central nervous system (CNS). Neuroinflammation might be a result of this to accelerate the progressive deterioration of neuronal functions during aging. In this regard, controlling inflammation through delaying and/or preventing chronic inflammatory diseases may be a potential strategy to prevent or modify the progression of Alzheimer's Disease (AD). Periodontitis is a chronic inflammatory disease of the oral cavity that is common among the elderly, especially for those who have decline in cognitive functions. While epidemiological findings support the association of chronic periodontitis and cognitive decline, whether they have causal relationship remains unclear. Nonetheless, the possibility that periodontopathogens, systemic immune cells and inflammatory cytokines could reach the CNS should not be overlooked. The impacts of periodontitis on CNS homeostasis and inflammation as a pathophysiological factor concerning the association between periodontitis and AD will be discussed in this review. Future work should elucidate the pathological pathways involved in periodontitis-induced cerebral infections and inflammation, and define the role of the latter in AD progression.
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204
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Das R, Chinnathambi S. Microglial priming of antigen presentation and adaptive stimulation in Alzheimer's disease. Cell Mol Life Sci 2019; 76:3681-3694. [PMID: 31093687 PMCID: PMC11105582 DOI: 10.1007/s00018-019-03132-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 12/21/2022]
Abstract
The prominent pathological consequences of Alzheimer's disease (AD) are the misfolding and mis-sorting of two cellular proteins, amyloid-β and microtubule-associated protein Tau. The accumulation of toxic phosphorylated Tau inside the neurons induces the increased processing of amyloid-β-associated signaling cascade and vice versa. Neuroinflammation-driven synaptic depletion and cognitive decline are substantiated by the cross talk of activated microglia and astroglia, leading to neuron degeneration. Microglia are the brain-resident immune effectors that prove their diverse functions in maintaining CNS homeostasis via collaboration with astrocytes and T lymphocytes. Age-related senescence and chronic inflammation activate microglia with increased pro-inflammatory markers, oxidative damage and phagocytosis. But the improper processing of misfolded protein via lysosomal pathway destines the spreading of 'seed' constituents to the nearby healthy neurons. Primed microglia process and present self-antigen such as amyloid-β and modified Tau to the infiltrated T lymphocytes through MHC I/II molecules. After an effective conversation with CD4+ T cells, microglial phenotype can be altered from pro-active M1 to neuro-protective M2 type, which corresponds to the tissue remodeling and homeostasis. In this review, we are focusing on the change in functionality of microglia from innate to adaptive immune response in the context of neuroprotection, which may help in the search of novel immune therapy in AD.
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Affiliation(s)
- Rashmi Das
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Pune, 411008, India
| | - Subashchandrabose Chinnathambi
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India.
- Academy of Scientific and Innovative Research (AcSIR), Pune, 411008, India.
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205
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Abstract
The endotoxin hypothesis of neurodegeneration is the hypothesis that endotoxin causes or contributes to neurodegeneration. Endotoxin is a lipopolysaccharide (LPS), constituting much of the outer membrane of gram-negative bacteria, present at high concentrations in gut, gums and skin and in other tissue during bacterial infection. Blood plasma levels of endotoxin are normally low, but are elevated during infections, gut inflammation, gum disease and neurodegenerative disease. Adding endotoxin at such levels to blood of healthy humans induces systemic inflammation and brain microglial activation. Adding high levels of endotoxin to the blood or body of rodents induces microglial activation, priming and/or tolerance, memory deficits and loss of brain synapses and neurons. Endotoxin promotes amyloid β and tau aggregation and neuropathology, suggesting the possibility that endotoxin synergises with different aggregable proteins to give different neurodegenerative diseases. Blood and brain endotoxin levels are elevated in Alzheimer's disease, which is accelerated by systemic infections, including gum disease. Endotoxin binds directly to APOE, and the APOE4 variant both sensitises to endotoxin and predisposes to Alzheimer's disease. Intestinal permeability increases early in Parkinson's disease, and injection of endotoxin into mice induces α-synuclein production and aggregation, as well as loss of dopaminergic neurons in the substantia nigra. The gut microbiome changes in Parkinson's disease, and changing the endotoxin-producing bacterial species can affect the disease in patients and mouse models. Blood endotoxin is elevated in amyotrophic lateral sclerosis, and endotoxin promotes TDP-43 aggregation and neuropathology. Peripheral diseases that elevate blood endotoxin, such as sepsis, AIDS and liver failure, also result in neurodegeneration. Endotoxin directly and indirectly activates microglia that damage neurons via nitric oxide, oxidants and cytokines, and by phagocytosis of synapses and neurons. The endotoxin hypothesis is unproven, but if correct, then neurodegeneration may be reduced by decreasing endotoxin levels or endotoxin-induced neuroinflammation.
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Affiliation(s)
- Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK.
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206
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Cagna DR, Donovan TE, McKee JR, Eichmiller F, Metz JE, Albouy JP, Marzola R, Murphy KR, Troeltzsch M. Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry. J Prosthet Dent 2019; 122:198-269. [PMID: 31405523 DOI: 10.1016/j.prosdent.2019.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 12/13/2022]
Abstract
This comprehensive review of the 2018 dental literature is provided to inform busy dentists about progress in the profession. Developed by the Committee on Scientific Investigation of the American Academy of Restorative Dentistry, each author brings discipline-specific expertise to one of the 8 sections of the report including (1) prosthodontics; (2) periodontics, alveolar bone, and peri-implant tissues; (3) implant dentistry; (4) dental materials and therapeutics; (5) occlusion and temporomandibular disorders; (6) sleep-related breathing disorders; (7) oral medicine and oral and maxillofacial surgery; and (8) dental caries and cariology. The report targets important information that will likely influence day-to-day treatment decisions. Each review is not intended to stand alone but to update interested readers so that they may visit source materials if greater detail is desired. As the profession continues its march toward evidence-based clinical decision-making, an already voluminous library of potentially valuable dental literature continues to grow. It is the intention of this review and its authors to provide assistance in navigating the extensive dental literature published in 2018. It is our hope that readers find this work useful in the clinical management of patients moving forward.
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Affiliation(s)
- David R Cagna
- Professor, Associate Dean, and Residency Director, Department of Prosthodontics, University of Tennessee Health Sciences Center, College of Dentistry, Memphis, Tenn.
| | - Terence E Donovan
- Professor and Head of Biomaterials, Department of Restorative Sciences, University of North Carolina School of Dentistry, Chapel Hill, NC
| | - James R McKee
- Private practice, Restorative Dentistry, Downers Grove, Ill
| | | | - James E Metz
- Private practice, Restorative Dentistry, Columbus, Ohio
| | - Jean-Pierre Albouy
- Assistant Professor, Department of Restorative Sciences, University of North Carolina School of Dentistry, Chapel Hill, NC
| | | | - Kevin R Murphy
- Associate Clinical Professor, Department of Periodontics, University of Maryland College of Dentistry, Baltimore, MD; Private practice, Periodontics and Prosthodontics, Baltimore, MD
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207
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Inyushin M, Zayas-Santiago A, Rojas L, Kucheryavykh Y, Kucheryavykh L. Platelet-generated amyloid beta peptides in Alzheimer's disease and glaucoma. Histol Histopathol 2019; 34:843-856. [PMID: 30945258 PMCID: PMC6667289 DOI: 10.14670/hh-18-111] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Amyloid beta (Aβ) peptides have been implicated in both Alzheimer's disease (AD) and glaucoma and have been shown to be the key etiological factor in these dangerous health complications. On the other hand, it is well known that Aβ peptide can be generated from its precursor protein and massively released from the blood to nearby tissue upon the activation of platelets due to their involvement in innate immunity and inflammation processes. Here we review evidence about the development of AD and glaucoma neuronal damage showing their dependence on platelet count and activation. The correlation between the effect on platelet count and the effectiveness of anti-AD and anti-glaucoma therapies suggest that platelets may be an important player in these diseases.
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Affiliation(s)
- Mikhail Inyushin
- School of Medicine, Universidad Central del Caribe (UCC), PR, USA.
| | | | - Legier Rojas
- School of Medicine, Universidad Central del Caribe (UCC), PR, USA
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208
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Hashioka S, Inoue K, Miyaoka T, Hayashida M, Wake R, Oh-Nishi A, Inagaki M. The Possible Causal Link of Periodontitis to Neuropsychiatric Disorders: More Than Psychosocial Mechanisms. Int J Mol Sci 2019; 20:E3723. [PMID: 31366073 PMCID: PMC6695849 DOI: 10.3390/ijms20153723] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/19/2019] [Accepted: 07/25/2019] [Indexed: 12/27/2022] Open
Abstract
Increasing evidence implies a possible causal link between periodontitis and neuropsychiatric disorders, such as Alzheimer's disease (AD) and major depression (MD). A possible mechanism underlying such a link can be explained by neuroinflammation induced by chronic systemic inflammation. This review article focuses on an overview of the biological and epidemiological evidence for a feasible causal link of periodontitis to neuropsychiatric disorders, including AD, MD, Parkinson's disease, and schizophrenia, as well as the neurological event, ischemic stroke. If there is such a link, a broad spectrum of neuropsychiatric disorders associated with neuroinflammation could be preventable and modifiable by simple daily dealings for oral hygiene. However, the notion that periodontitis is a risk factor for neuropsychiatric disorders remains to be effectively substantiated.
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Affiliation(s)
- Sadayuki Hashioka
- Department of Psychiatry, Shimane University, 89-1 Enya-cho, Izumo 693-8501, Japan.
| | - Ken Inoue
- Health Service Center, Kochi University, 2-5-1 Akebono-cho, Kochi 780-8520, Japan
| | - Tsuyoshi Miyaoka
- Department of Psychiatry, Shimane University, 89-1 Enya-cho, Izumo 693-8501, Japan
| | - Maiko Hayashida
- Department of Psychiatry, Shimane University, 89-1 Enya-cho, Izumo 693-8501, Japan
| | - Rei Wake
- Department of Psychiatry, Shimane University, 89-1 Enya-cho, Izumo 693-8501, Japan
| | - Arata Oh-Nishi
- Department of Psychiatry, Shimane University, 89-1 Enya-cho, Izumo 693-8501, Japan
| | - Masatoshi Inagaki
- Department of Psychiatry, Shimane University, 89-1 Enya-cho, Izumo 693-8501, Japan
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209
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Patrick KL, Bell SL, Weindel CG, Watson RO. Exploring the "Multiple-Hit Hypothesis" of Neurodegenerative Disease: Bacterial Infection Comes Up to Bat. Front Cell Infect Microbiol 2019; 9:138. [PMID: 31192157 PMCID: PMC6546885 DOI: 10.3389/fcimb.2019.00138] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/16/2019] [Indexed: 12/23/2022] Open
Abstract
Despite major strides in personalized genomics, it remains poorly understood why neurodegenerative diseases occur in only a fraction of individuals with a genetic predisposition and conversely, why individuals with no genetic risk of a disorder develop one. Chronic diseases like Alzheimer's, Parkinson's, and Multiple sclerosis are speculated to result from a combination of genetic and environmental factors, a concept commonly referred to as the “multiple hit hypothesis.” A number of bacterial infections have been linked to increased risk of neurodegeneration, and in some cases, clearance of bacterial pathogens has been correlated with amelioration of central nervous system (CNS) deficits. Additionally, mutations in several genes known to contribute to CNS disorders like Parkinson's Disease have repeatedly been implicated in susceptibility to intracellular bacterial infection. Recent data has begun to demonstrate roles for these genes (PARK2, PINK1, and LRRK2) in modulating innate immune outcomes, suggesting that immune dysregulation may play an even more important role in neurodegeneration than previously appreciated. This review will broadly explore the connections between bacterial infection, immune dysregulation, and CNS disorders. Understanding this interplay and how bacterial pathogenesis contributes to the “multiple-hit hypothesis” of neurodegeneration will be crucial to develop therapeutics to effectively treat both neurodegeneration and infection.
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Affiliation(s)
- Kristin L Patrick
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX, United States
| | - Samantha L Bell
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX, United States
| | - Chi G Weindel
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX, United States
| | - Robert O Watson
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX, United States
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210
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Díaz-Zúñiga J, Muñoz Y, Melgar-Rodríguez S, More J, Bruna B, Lobos P, Monasterio G, Vernal R, Paula-Lima A. Serotype b of Aggregatibacter actinomycetemcomitans triggers pro-inflammatory responses and amyloid beta secretion in hippocampal cells: a novel link between periodontitis and Alzheimer´s disease? J Oral Microbiol 2019; 11:1586423. [PMID: 31044031 PMCID: PMC6484476 DOI: 10.1080/20002297.2019.1586423] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/31/2019] [Accepted: 02/13/2019] [Indexed: 01/18/2023] Open
Abstract
Introduction: Previous reports have proposed that Periodontal disease (PDis) predisposes to Alzheimer's disease (AD), both highly prevalent pathologies among the elderly. The bacteria Aggregatibacter actinomycetemcomitans (Aa), associated with the most aggressive forms of PDis, are classified in different serotypes with distinct virulence according to the antigenicity of their lipopolysaccharide (LPS). Methods: Here, we determined the effects of purified LPS, from serotypes a, b or c of Aa, on primary cultures of microglia or mixed hippocampal cells. Results: We found that both culture types exhibited higher levels of inflammatory cytokines (IL-1β, IL-6 and TNFα) when treated with serotype b-LPS, compared with controls, as quantified by qPCR and/or ELISA. Also, cultures treated with serotype a-LPS displayed increased mRNA levels of the modulatory cytokines IL-4 and IL-10. Mixed hippocampal cultures treated with serotype b-LPS exhibited severe neuronal morphological changes and displayed increased levels of secreted Aβ1-42 peptide. These results indicate that LPS from different Aa serotypes triggers discriminatory immune responses, which differentially affect primary hippocampal cells. Conclusion: Altogether, our results show that treatment with serotype b-LPS triggers the secretion of proinflammatory cytokines by microglia, induces neurite shrinking, and increases the extracellular Aβ1-42 levels, all features strongly associated with the etiology of AD.
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Affiliation(s)
- J Díaz-Zúñiga
- Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Y Muñoz
- Aging Cellular Laboratory, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - S Melgar-Rodríguez
- Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - J More
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - B Bruna
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - P Lobos
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - G Monasterio
- Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - R Vernal
- Department of Conservative Dentistry, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.,Dentistry Unit, Faculty of Health Sciences, Universidad Autónoma de Chile, Temuco, Chile
| | - A Paula-Lima
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
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211
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Poor Oral Health and Its Neurological Consequences: Mechanisms of Porphyromonas gingivalis Involvement in Cognitive Dysfunction. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s40496-019-0212-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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212
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Toffa DH, Magnerou MA, Kassab A, Hassane Djibo F, Sow AD. Can magnesium reduce central neurodegeneration in Alzheimer's disease? Basic evidences and research needs. Neurochem Int 2019; 126:195-202. [PMID: 30905744 DOI: 10.1016/j.neuint.2019.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/15/2019] [Accepted: 03/18/2019] [Indexed: 12/26/2022]
Abstract
Magnesium (Mg) is a crucial divalent cation with more than 300 cellular functions. This ion shows therapeutic properties in several neurological diseases. Although there are numerous basic evidences showing that Mg can inhibit pathological processes involved in neuroglial degeneration, this low-cost option is not well-considered in clinical research and practice for now. Nevertheless, none of the expensive drugs currently recommended by the classic guidelines (in addition to physiological rehabilitation) had shown exceptional effectiveness. Herein, focusing on Alzheimer's disease (AD), we analyze the therapeutic pathways that support the use of Mg for neurogenesis and neuroprotection. According to experimental findings reviewed, Mg shows interesting abilities to facilitate toxin clearance, reduce neuroinflammation, inhibit the pathologic processing of amyloid protein precursor (APP) as well as the abnormal tau protein phosphorylation, and to reverse the deregulation of N-methyl-D-aspartate receptors. Currently, some crucial details of the mechanisms involved in these proved effects remain elusive and clinical background is poor. Therefore, further studies are required to enable a better overview on pharmacodynamic targets of Mg and thus, to find optimal pharmacologic strategies for clinical use of this ion.
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Affiliation(s)
- Dènahin Hinnoutondji Toffa
- Epilepsy Lab, CRCHUM, Université de Montréal, Montreal, Canada; Neurology Division, CHUM, Université de Montréal, Montreal, Canada.
| | | | - Ali Kassab
- Epilepsy Lab, CRCHUM, Université de Montréal, Montreal, Canada
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213
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Singhrao SK, Olsen I. Assessing the role of Porphyromonas gingivalis in periodontitis to determine a causative relationship with Alzheimer's disease. J Oral Microbiol 2019; 11:1563405. [PMID: 30728914 PMCID: PMC6352933 DOI: 10.1080/20002297.2018.1563405] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/05/2018] [Accepted: 12/13/2018] [Indexed: 01/14/2023] Open
Abstract
Chronic periodontitis of 10 years' duration is reported to become a twofold risk factor for the development of Alzheimer's disease (AD). Periodontitis is modifiable, and this fits with the current action plan for preventing AD. However, until periodontitis, becomes acknowledged as a firm risk factor for AD, this risk will continue. Here, we put forward our own argument based on the current literature for in vivo infection-mediated periodontal disease models supporting the antimicrobial protection hypothesis of AD and interventional studies supporting the causal links. Oral infections with Porphyromonas gingivalis, or introduction of its lipopolysaccharide (LPS), in various mouse models has demonstrated the development of key neuropathological hallmark lesions defining AD. These are extracellular amyloid-beta plaques, phosphorylated tau, neurofibrillary tangles, widespread acute and chronic inflammation, blood-brain barrier defects together with the clinical phenotype showing impaired learning and spatial memory. Live P. gingivalis and its LPS (commercial or from 'microbullets') are powerful peripheral and intracerebral inflammatory signalling initiators, and this has direct implications on memory and lesion development. Maintaining a healthy oral microbiome and managing periodontal disease with regular surveillance and good oral hygiene throughout life is likely to reduce the unnecessary burden of AD in some individuals.
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Affiliation(s)
- Sim K Singhrao
- Dementia and Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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214
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Sun L, Ma L, Zhang H, Cao Y, Wang C, Hou N, Huang N, von Deneen KM, Zhao C, Shi Y, Pan Y, Wang M, Ji G, Nie Y. Fto Deficiency Reduces Anxiety- and Depression-Like Behaviors in Mice via Alterations in Gut Microbiota. Theranostics 2019; 9:721-733. [PMID: 30809304 PMCID: PMC6376469 DOI: 10.7150/thno.31562] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/27/2018] [Indexed: 01/16/2023] Open
Abstract
Depression and obesity have high concurrence within individuals, which may be explained by sharing the same risk factors, including disruption of the intestinal microbiota. However, evidence that delineated the causal connections is extremely scarce. Methods: Mice lacking fat mass- and obesity-associated gene (Fto) were generated. Fto-deficient and wild-type control mice were subjected to novel conditions with or without chronic unpredictable mild stress (CUMS) for 6 weeks. Some mice were treated with antibiotics via their drinking water for 6 weeks in order to deplete their microbiota. Behavioral tests were performed to evaluate anxiety- and depression-like behaviors. 16S rRNA amplicon and metagenomic sequencing were employed to analyse fecal microbiota. Plasma levels of inflammatory cytokines and lipopolysaccharides (LPS) were also compared. Results: Deletion of Fto led to lower body weight and decreased anxiety- and depression-like behaviors, Fto+/- mice were also less susceptible to stress stimulation, highlighting the essential role of Fto in pathogenesis of depression. With regard to gut microbiota, Fto deficiency mice harbored specific bacterial signature of suppressing inflammation, characterized with higher abundance of Lactobacillus, lower Porphyromonadaceae and Helicobacter. Critically, behavioral alterations of Fto+/- mice are mediated by shift in gut microbiota, as such changes can be partially attenuated using antibiotics. Exposure to CUMS increased serum IL-6 level while Fto deficiency reduced its level, which may be explained by a lower LPS concentration. Conclusion: Together, our findings uncover the roles of Fto on depression and provide insights into microbiota-related biological mechanisms underlying the association between obesity and depression.
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Affiliation(s)
- Lijuan Sun
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an 710032, China
- Department of Clinical Nutrition, Xijing Hospital, The Fourth Military Medical University, Xi׳an, 710032, China
| | - Lanjing Ma
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an 710032, China
| | - Haohao Zhang
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an 710032, China
| | - Ying Cao
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an 710032, China
| | - Chenchen Wang
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an 710032, China
| | - Nannan Hou
- National Institute of Biological Sciences, Number 7 Science Park Road, Zhongguancun Life Science Park, Beijing, MI 102206, China
| | - Niu Huang
- National Institute of Biological Sciences, Number 7 Science Park Road, Zhongguancun Life Science Park, Beijing, MI 102206, China
| | - Karen M. von Deneen
- Center for Brain Imaging, School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710126, China
| | - Changhai Zhao
- Department of Clinical Nutrition, Xijing Hospital, The Fourth Military Medical University, Xi׳an, 710032, China
| | - Yupeng Shi
- Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an, China
| | - Yan Pan
- Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an, China
| | - Meixia Wang
- Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an, China
| | - Gang Ji
- Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an, China
| | - Yongzhan Nie
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an 710032, China
- Xijing Hospital of Digestive Diseases, The Fourth Military Medical University, Xi'an, China
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Singhrao SK, Olsen I. Are Porphyromonas gingivalis Outer Membrane Vesicles Microbullets for Sporadic Alzheimer's Disease Manifestation? J Alzheimers Dis Rep 2018; 2:219-228. [PMID: 30599043 PMCID: PMC6311351 DOI: 10.3233/adr-180080] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our research into Alzheimer's disease (AD) focuses on the oral cavity and the brain, from which key evaluations of prospective and retrospective population-based data have shown that chronic periodontal disease existing for ten-years or over doubles the risk for the sporadic form of AD. Furthermore, Porphyromonas gingivalis (P. gingivalis) mono-infections in established periodontal lesions, or introducing its lipopolysachharide (LPS), as demonstrated in in vivo studies, show hallmark pathology inclusive of extracellular amyloid plaques and phospho-tau bound neurofibrillary tangles with AD-like phenotype. Other studies have shown that if periodontitis remains untreated in human AD patients, cognitive decline ensues. This is a bi-directional relationship meaning that the converse is also true; treating periodontal disease in AD patients improves memory. Bacterial cultures and established oral biofilms generate vast numbers of microvesicles and P. gingivalis outer membrane vesicles encase key virulence factors (LPS, gingipains, capsule, fimbriae) as though they are complete destructive "microbullets" when shed in the host. This provides P. gingivalis additional arsenal to manipulate its entry into disparate organs, hijack phagocytosis, destroy tissues, and affect complement related genes while transducing the onset of proinflammatory signaling cascades. The resulting inflammatory mediators may be the cause of disease defining lesions and cognitive decline typical of clinical AD.
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Affiliation(s)
- Sim K Singhrao
- Dementia and Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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