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Naik B, Sasikumar J, Das SP. From Skin and Gut to the Brain: The Infectious Journey of the Human Commensal Fungus Malassezia and Its Neurological Consequences. Mol Neurobiol 2024:10.1007/s12035-024-04270-w. [PMID: 38871941 DOI: 10.1007/s12035-024-04270-w] [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: 01/12/2024] [Accepted: 05/27/2024] [Indexed: 06/15/2024]
Abstract
The human mycobiome encompasses diverse communities of fungal organisms residing within the body and has emerged as a critical player in shaping health and disease. While extensive research has focused on the skin and gut mycobiome, recent investigations have pointed toward the potential role of fungal organisms in neurological disorders. Among those fungal organisms, the presence of the commensal fungus Malassezia in the brain has created curiosity because of its commensal nature and primary association with the human skin and gut. This budding yeast is responsible for several diseases, such as Seborrheic dermatitis, Atopic dermatitis, Pityriasis versicolor, Malassezia folliculitis, dandruff, and others. However recent findings surprisingly show the presence of Malassezia DNA in the brain and have been linked to diseases like Alzheimer's disease, Parkinson's disease, Multiple sclerosis, and Amyotrophic lateral sclerosis. The exact role of Malassezia in these disorders is unknown, but its ability to infect human cells, travel through the bloodstream, cross the blood-brain barrier, and reside along with the lipid-rich neuronal cells are potential mechanisms responsible for pathogenesis. This also includes the induction of pro-inflammatory cytokines, disruption of the blood-brain barrier, gut-microbe interaction, and accumulation of metabolic changes in the brain environment. In this review, we discuss these key findings from studies linking Malassezia to neurological disorders, emphasizing the complex and multifaceted nature of these cases. Furthermore, we discuss potential mechanisms through which Malassezia might contribute to the development of neurological conditions. Future investigations will open up new avenues for our understanding of the fungal gut-brain axis and how it influences human behavior. Collaborative research efforts among microbiologists, neuroscientists, immunologists, and clinicians hold promise for unraveling the enigmatic connections between human commensal Malassezia and neurological disorders.
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Affiliation(s)
- Bharati Naik
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, 575018, India
| | - Jayaprakash Sasikumar
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, 575018, India
| | - Shankar Prasad Das
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, 575018, India.
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2
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Ekwudo MN, Gubert C, Hannan AJ. The microbiota-gut-brain axis in Huntington's disease: pathogenic mechanisms and therapeutic targets. FEBS J 2024. [PMID: 38426291 DOI: 10.1111/febs.17102] [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: 10/13/2023] [Revised: 01/08/2024] [Accepted: 02/14/2024] [Indexed: 03/02/2024]
Abstract
Huntington's disease (HD) is a currently incurable neurogenerative disorder and is typically characterized by progressive movement disorder (including chorea), cognitive deficits (culminating in dementia), psychiatric abnormalities (the most common of which is depression), and peripheral symptoms (including gastrointestinal dysfunction). There are currently no approved disease-modifying therapies available for HD, with death usually occurring approximately 10-25 years after onset, but some therapies hold promising potential. HD subjects are often burdened by chronic diarrhea, constipation, esophageal and gastric inflammation, and a susceptibility to diabetes. Our understanding of the microbiota-gut-brain axis in HD is in its infancy and growing evidence from preclinical and clinical studies suggests a role of gut microbial population imbalance (gut dysbiosis) in HD pathophysiology. The gut and the brain can communicate through the enteric nervous system, immune system, vagus nerve, and microbiota-derived-metabolites including short-chain fatty acids, bile acids, and branched-chain amino acids. This review summarizes supporting evidence demonstrating the alterations in bacterial and fungal composition that may be associated with HD. We focus on mechanisms through which gut dysbiosis may compromise brain and gut health, thus triggering neuroinflammatory responses, and further highlight outcomes of attempts to modulate the gut microbiota as promising therapeutic strategies for HD. Ultimately, we discuss the dearth of data and the need for more longitudinal and translational studies in this nascent field. We suggest future directions to improve our understanding of the association between gut microbes and the pathogenesis of HD, and other 'brain and body disorders'.
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Affiliation(s)
- Millicent N Ekwudo
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Carolina Gubert
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
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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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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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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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Severance EG. Fungal Forces in Mental Health: Microbial Meddlers or Function Fixers? Curr Top Behav Neurosci 2022; 61:163-179. [PMID: 35543867 DOI: 10.1007/7854_2022_364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the mental health field, the gut-brain axis and associated pathways represent putative mechanisms by which gastrointestinal (GI) microbes and their gene products and metabolites can access and influence the central nervous system (CNS). These GI-centered investigations focus on bacteria, with significant information gaps existing for other microbial community members, such as fungi. Fungi are part of a complex and functionally diverse taxonomic kingdom whose interactions with hosts can be conversely deadly and beneficial. As serious sources of morbidity and mortality, fungal pathogens can quickly turn healthy microbiomes into toxic cycles of inflammation, gut permeability, and dysbiosis. Fungal commensals are also important human symbionts that provide a rich source of physiological functions to the host, such as protection against intestinal injuries, maintenance of epithelial structural integrities, and immune system development and regulation. Promising treatment compounds derived from fungi include antibiotics, probiotics, and antidepressants. Here I aim to illuminate the many attributes of fungi as they are applicable to overall improving our understanding of the mechanisms at work in psychiatric disorders. Healing the gut and its complex ecosystem is currently achievable through diet, probiotics, prebiotics, and other strategies, yet it is critical to recognize that the success of these interventions relies on a more precisely defined role of the fungal and other non-bacterial components of the microbiome.
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Affiliation(s)
- Emily G Severance
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Phuna ZX, Madhavan P. A CLOSER LOOK AT THE MYCOBIOME IN ALZHEIMER'S DISEASE: FUNGAL SPECIES, PATHOGENESIS AND TRANSMISSION. Eur J Neurosci 2022; 55:1291-1321. [DOI: 10.1111/ejn.15599] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Zhi Xin Phuna
- School of Medicine, Faculty of Health & Medical Sciences, Taylor’s University Malaysia Subang Jaya Selangor
| | - Priya Madhavan
- School of Medicine, Faculty of Health & Medical Sciences, Taylor’s University Malaysia Subang Jaya Selangor
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Nguyen VTT, König S, Eggert S, Endres K, Kins S. The role of mycotoxins in neurodegenerative diseases: current state of the art and future perspectives of research. Biol Chem 2021; 403:3-26. [PMID: 34449171 DOI: 10.1515/hsz-2021-0214] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/16/2021] [Indexed: 01/02/2023]
Abstract
Mycotoxins are fungal metabolites that can cause various diseases in humans and animals. The adverse health effects of mycotoxins such as liver failure, immune deficiency, and cancer are well-described. However, growing evidence suggests an additional link between these fungal metabolites and neurodegenerative diseases. Despite the wealth of these initial reports, reliable conclusions are still constrained by limited access to human patients and availability of suitable cell or animal model systems. This review summarizes knowledge on mycotoxins associated with neurodegenerative diseases and the assumed underlying pathophysiological mechanisms. The limitations of the common in vivo and in vitro experiments to identify the role of mycotoxins in neurotoxicity and thereby in neurodegenerative diseases are elucidated and possible future perspectives to further evolve this research field are presented.
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Affiliation(s)
- Vu Thu Thuy Nguyen
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University Mainz, Untere Zahlbacher Str. 8, D-55131 Mainz, Germany
| | - Svenja König
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, D-67663 Kaiserslautern, Germany
| | - Simone Eggert
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, D-67663 Kaiserslautern, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University Mainz, Untere Zahlbacher Str. 8, D-55131 Mainz, Germany
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, D-67663 Kaiserslautern, Germany
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Shi M, Li C, Tian X, Chu F, Zhu J. Can Control Infections Slow Down the Progression of Alzheimer's Disease? Talking About the Role of Infections in Alzheimer's Disease. Front Aging Neurosci 2021; 13:685863. [PMID: 34366826 PMCID: PMC8339924 DOI: 10.3389/fnagi.2021.685863] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/24/2021] [Indexed: 01/07/2023] Open
Abstract
Alzheimer’s disease as the most common age-related dementia affects more than 40 million people in the world, representing a global public health priority. However, the pathogenesis of Alzheimer’s disease (AD) is complex, and it remains unclear. Over the past decades, all efforts made in the treatments of AD, with targeting the pathogenic amyloid β (Aβ), neurofibrillary tangles, and misfolded tau protein, were failed. Recently, many studies have hinted that infection, and chronic inflammation that caused by infection are crucial risk factors for AD development and progress. In the review, we analyzed the role of infections caused by bacteria, viruses, and other pathogens in the pathogenesis of AD and its animal models, and explored the therapeutic possibility with anti-infections for AD. However, based on the published data, it is still difficult to determine their causal relationship between infection and AD due to contradictory results. We think that the role of infection in the pathogenesis of AD should not be ignored, even though infection does not necessarily cause AD, it may act as an accelerator in AD at least. It is essential to conduct the longitudinal studies and randomized controlled trials in humans, which can determine the role of infection in AD and clarify the links between infection and the pathological features of AD. Finding targeting infection drugs and identifying the time window for applying antibacterial or antiviral intervention may be more promising for future clinical therapeutic strategies in AD.
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Affiliation(s)
- Mingchao Shi
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Chunrong Li
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Xiaoping Tian
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital of Shenzhen University Medical College, Shenzhen, China
| | - Fengna Chu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Jie Zhu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
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Health Potential of Clery Strawberries: Enzymatic Inhibition and Anti- Candida Activity Evaluation. Molecules 2021; 26:molecules26061731. [PMID: 33808822 PMCID: PMC8003815 DOI: 10.3390/molecules26061731] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 11/16/2022] Open
Abstract
Strawberries, belonging to cultivar Clery (Fragaria × ananassa Duchesne ex Weston) and to a graft obtained by crossing Clery and Fragaria vesca L., were chosen for a study on their health potential, with regard to the prevention of chronic and degenerative diseases. Selected samples, coming from fresh and defrosted berries, submitted to different homogenization techniques combined with thermal and microwave treatments, had been previously analyzed in their polyphenolic content and antioxidant capacity. In the present work, these homogenates were evaluated in relation to their enzymatic inhibition activity towards acetylcholinesterase and butyrylcholinesterase, α-amylase, α-glucosidase and tyrosinase. All these enzymes, involved in the onset of diabetes, and neurodegenerative and other chronic diseases, were modulated by the tested samples. The inhibitory effect on tyrosinase and cholinesterase was the most valuable. Antifungal activity against Candida albicans, recently shown to play a crucial role in human gut diseases as well as diabetes, rheumatoid arthritis and Alzheimer’s disease, was also shown in vitro and confirmed by the in vivo text on Galleria mellonella. Overall, the obtained results confirm once again the health potential of strawberries; however, the efficacy is dependent on high quality products submitted to correct processing flow charts.
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Vigasova D, Nemergut M, Liskova B, Damborsky J. Multi-pathogen infections and Alzheimer's disease. Microb Cell Fact 2021; 20:25. [PMID: 33509204 PMCID: PMC7844946 DOI: 10.1186/s12934-021-01520-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 01/16/2021] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease (AD) is a chronic neurodegenerative disease associated with the overproduction and accumulation of amyloid-β peptide and hyperphosphorylation of tau proteins in the brain. Despite extensive research on the amyloid-based mechanism of AD pathogenesis, the underlying cause of AD is not fully understood. No disease-modifying therapies currently exist, and numerous clinical trials have failed to demonstrate any benefits. The recent discovery that the amyloid-β peptide has antimicrobial activities supports the possibility of an infectious aetiology of AD and suggests that amyloid-β plaque formation might be induced by infection. AD patients have a weakened blood-brain barrier and immune system and are thus at elevated risk of microbial infections. Such infections can cause chronic neuroinflammation, production of the antimicrobial amyloid-β peptide, and neurodegeneration. Various pathogens, including viruses, bacteria, fungi, and parasites have been associated with AD. Most research in this area has focused on individual pathogens, with herpesviruses and periodontal bacteria being most frequently implicated. The purpose of this review is to highlight the potential role of multi-pathogen infections in AD. Recognition of the potential coexistence of multiple pathogens and biofilms in AD's aetiology may stimulate the development of novel approaches to its diagnosis and treatment. Multiple diagnostic tests could be applied simultaneously to detect major pathogens, followed by anti-microbial treatment using antiviral, antibacterial, antifungal, and anti-biofilm agents.
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Affiliation(s)
- Dana Vigasova
- International Clinical Research Center, St. Anne’s University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
- Department of Experimental Biology and RECETOX, Faculty of Science, Loschmidt Laboratories, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Michal Nemergut
- Department of Experimental Biology and RECETOX, Faculty of Science, Loschmidt Laboratories, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Barbora Liskova
- Department of Experimental Biology and RECETOX, Faculty of Science, Loschmidt Laboratories, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Jiri Damborsky
- International Clinical Research Center, St. Anne’s University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
- Department of Experimental Biology and RECETOX, Faculty of Science, Loschmidt Laboratories, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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12
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The Viral Hypothesis in Alzheimer's Disease: Novel Insights and Pathogen-Based Biomarkers. J Pers Med 2020; 10:jpm10030074. [PMID: 32751069 PMCID: PMC7563893 DOI: 10.3390/jpm10030074] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 02/07/2023] Open
Abstract
Early diagnosis of Alzheimer’s disease (AD) and the identification of significant risk factors are necessary to better understand disease progression, and to develop intervention-based therapies prior to significant neurodegeneration. There is thus a critical need to establish biomarkers which can predict the risk of developing AD before the onset of cognitive decline. A number of studies have indicated that exposure to various microbial pathogens can accelerate AD pathology. Additionally, several studies have indicated that amyloid-β possess antimicrobial properties and may act in response to infection as a part of the innate immune system. These findings have led some to speculate that certain types of infections may play a significant role in AD pathogenesis. In this review, we will provide an overview of studies which suggest pathogen involvement in AD. Additionally, we will discuss a number of pathogen-associated biomarkers which may be effective in establishing AD risk. Infections that increase the risk of AD represent a modifiable risk factor which can be treated with therapeutic intervention. Pathogen-based biomarkers may thus be a valuable tool for evaluating and decreasing AD risk across the population.
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Bulgart HR, Neczypor EW, Wold LE, Mackos AR. Microbial involvement in Alzheimer disease development and progression. Mol Neurodegener 2020; 15:42. [PMID: 32709243 PMCID: PMC7382139 DOI: 10.1186/s13024-020-00378-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 04/29/2020] [Indexed: 02/08/2023] Open
Abstract
Alzheimer disease (AD) is the most prominent form of dementia and the 5th leading cause of death in individuals over 65. AD is a complex disease stemming from genetic, environmental, and lifestyle factors. It is known that AD patients have increased levels of senile plaques, neurofibrillary tangles, and neuroinflammation; however, the mechanism(s) by which the plaques, tangles, and neuroinflammation manifest remain elusive. A recent hypothesis has emerged that resident bacterial populations contribute to the development and progression of AD by contributing to neuroinflammation, senile plaque formation, and potentially neurofibrillary tangle accumulation (Fig. 1). This review will highlight recent studies involved in elucidating microbial involvement in AD development and progression.
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Affiliation(s)
- Hannah R. Bulgart
- Biomedical Sciences Graduate Program, College of Medicine, The Ohio State University, Columbus, OH USA
| | - Evan W. Neczypor
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH USA
- College of Nursing, The Ohio State University, 1585 Neil Ave, Columbus, OH 43210 USA
| | - Loren E. Wold
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH USA
- College of Nursing, The Ohio State University, 1585 Neil Ave, Columbus, OH 43210 USA
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine and Wexner Medical Center, Columbus, OH USA
| | - Amy R. Mackos
- College of Nursing, The Ohio State University, 1585 Neil Ave, Columbus, OH 43210 USA
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ALSUntangled No. 50: Antifungal Therapy. Amyotroph Lateral Scler Frontotemporal Degener 2019; 20:625-629. [PMID: 31155963 DOI: 10.1080/21678421.2019.1622197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Gosztyla ML, Brothers HM, Robinson SR. Alzheimer's Amyloid-β is an Antimicrobial Peptide: A Review of the Evidence. J Alzheimers Dis 2019; 62:1495-1506. [PMID: 29504537 DOI: 10.3233/jad-171133] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The amyloid-β (Aβ) peptide has long been considered to be the driving force behind Alzheimer's disease (AD). However, clinical trials that have successfully reduced Aβ burden in the brain have not slowed the cognitive decline, and in some instances, have resulted in adverse outcomes. While these results can be interpreted in different ways, a more nuanced picture of Aβ is emerging that takes into account the facts that the peptide is evolutionarily conserved and is present throughout life in cognitively normal individuals. Recent evidence indicates a role for Aβ as an antimicrobial peptide (AMP), a class of innate immune defense molecule that utilizes fibrillation to protect the host from a wide range of infectious agents. In humans and in animal models, infection of the brain frequently leads to increased amyloidogenic processing of the amyloid-β protein precursor (AβPP) and resultant fibrillary aggregates of Aβ. Evidence from in vitro and in vivo studies demonstrates that Aβ oligomers have potent, broad-spectrum antimicrobial properties by forming fibrils that entrap pathogens and disrupt cell membranes. Importantly, overexpression of Aβ confers increased resistance to infection from both bacteria and viruses. The antimicrobial role of Aβ may explain why increased rates of infection have been observed in some of the AD clinical trials that depleted Aβ. Perhaps progress toward a cure for AD will accelerate once treatment strategies begin to take into account the likely physiological functions of this enigmatic peptide.
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Affiliation(s)
- Maya L Gosztyla
- Department of Neuroscience, The Ohio State University, Columbus, OH, USA
| | - Holly M Brothers
- Department of Psychology, The Ohio State University, Columbus, OH, USA
| | - Stephen R Robinson
- Discipline of Psychology, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia
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16
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Wu Y, Du S, Johnson JL, Tung HY, Landers CT, Liu Y, Seman BG, Wheeler RT, Costa-Mattioli M, Kheradmand F, Zheng H, Corry DB. Microglia and amyloid precursor protein coordinate control of transient Candida cerebritis with memory deficits. Nat Commun 2019; 10:58. [PMID: 30610193 PMCID: PMC6320369 DOI: 10.1038/s41467-018-07991-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 12/07/2018] [Indexed: 12/12/2022] Open
Abstract
Bloodborne infections with Candida albicans are an increasingly recognized complication of modern medicine. Here, we present a mouse model of low-grade candidemia to determine the effect of disseminated infection on cerebral function and relevant immune determinants. We show that intravenous injection of 25,000 C. albicans cells causes a highly localized cerebritis marked by the accumulation of activated microglial and astroglial cells around yeast aggregates, forming fungal-induced glial granulomas. Amyloid precursor protein accumulates within the periphery of these granulomas, while cleaved amyloid beta (Aβ) peptides accumulate around the yeast cells. CNS-localized C. albicans further activate the transcription factor NF-κB and induce production of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor (TNF), and Aβ peptides enhance both phagocytic and antifungal activity from BV-2 cells. Mice infected with C. albicans display mild memory impairment that resolves with fungal clearance. Our results warrant additional studies to understand the effect of chronic cerebritis on cognitive and immune function. The potential links between infections and neurodegenerative disorders are unclear. Here, Wu et al. present a mouse model of low-grade candidemia characterized by highly localized cerebritis, accumulation of amyloid precursor protein and beta peptides, and mild memory impairment that resolves with fungal clearance.
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Affiliation(s)
- Yifan Wu
- Departments of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Biology of Inflammation Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Shuqi Du
- Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Jennifer L Johnson
- Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Memory and Brain Research Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Hui-Ying Tung
- Departments of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Biology of Inflammation Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Cameron T Landers
- Biology of Inflammation Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Translational Biology and Molecular Medicine Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Yuwei Liu
- Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Memory and Brain Research Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Brittany G Seman
- Molecular and Biomedical Sciences, University of Maine, Orono, ME, 04469, USA
| | - Robert T Wheeler
- Molecular and Biomedical Sciences, University of Maine, Orono, ME, 04469, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, 04469, USA
| | - Mauro Costa-Mattioli
- Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Memory and Brain Research Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Farrah Kheradmand
- Departments of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Biology of Inflammation Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Michael E. DeBakey VA Center for Translational Research on Inflammatory Diseases, Houston, TX, 77030, USA
| | - Hui Zheng
- Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Memory and Brain Research Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - David B Corry
- Departments of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA. .,Biology of Inflammation Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA. .,Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA. .,Michael E. DeBakey VA Center for Translational Research on Inflammatory Diseases, Houston, TX, 77030, USA.
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17
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Brothers HM, Gosztyla ML, Robinson SR. The Physiological Roles of Amyloid-β Peptide Hint at New Ways to Treat Alzheimer's Disease. Front Aging Neurosci 2018; 10:118. [PMID: 29922148 PMCID: PMC5996906 DOI: 10.3389/fnagi.2018.00118] [Citation(s) in RCA: 210] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/06/2018] [Indexed: 12/11/2022] Open
Abstract
Amyloid-ß (Aß) is best known as the misfolded peptide that is involved in the pathogenesis of Alzheimer's disease (AD), and it is currently the primary therapeutic target in attempts to arrest the course of this disease. This notoriety has overshadowed evidence that Aß serves several important physiological functions. Aß is present throughout the lifespan, it has been found in all vertebrates examined thus far, and its molecular sequence shows a high degree of conservation. These features are typical of a factor that contributes significantly to biological fitness, and this suggestion has been supported by evidence of functions that are beneficial for the brain. The putative roles of Aß include protecting the body from infections, repairing leaks in the blood-brain barrier, promoting recovery from injury, and regulating synaptic function. Evidence for these beneficial roles comes from in vitro and in vivo studies, which have shown that the cellular production of Aß rapidly increases in response to a physiological challenge and often diminishes upon recovery. These roles are further supported by the adverse outcomes of clinical trials that have attempted to deplete Aß in order to treat AD. We suggest that anti-Aß therapies will produce fewer adverse effects if the known triggers of Aß deposition (e.g., pathogens, hypertension, and diabetes) are addressed first.
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Affiliation(s)
- Holly M Brothers
- Department of Psychology, The Ohio State University Columbus, Columbus, OH, United States
| | - Maya L Gosztyla
- Department of Neuroscience, The Ohio State University Columbus, Columbus, OH, United States
| | - Stephen R Robinson
- Discipline of Psychology, School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
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18
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Harris SA, Harris EA. Molecular Mechanisms for Herpes Simplex Virus Type 1 Pathogenesis in Alzheimer's Disease. Front Aging Neurosci 2018; 10:48. [PMID: 29559905 PMCID: PMC5845560 DOI: 10.3389/fnagi.2018.00048] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 02/12/2018] [Indexed: 12/12/2022] Open
Abstract
This review focuses on research in the areas of epidemiology, neuropathology, molecular biology and genetics that implicates herpes simplex virus type 1 (HSV-1) as a causative agent in the pathogenesis of sporadic Alzheimer’s disease (AD). Molecular mechanisms whereby HSV-1 induces AD-related pathophysiology and pathology, including neuronal production and accumulation of amyloid beta (Aβ), hyperphosphorylation of tau proteins, dysregulation of calcium homeostasis, and impaired autophagy, are discussed. HSV-1 causes additional AD pathologies through mechanisms that promote neuroinflammation, oxidative stress, mitochondrial damage, synaptic dysfunction, and neuronal apoptosis. The AD susceptibility genes apolipoprotein E (APOE), phosphatidylinositol binding clathrin assembly protein (PICALM), complement receptor 1 (CR1) and clusterin (CLU) are involved in the HSV lifecycle. Polymorphisms in these genes may affect brain susceptibility to HSV-1 infection. APOE, for example, influences susceptibility to certain viral infections, HSV-1 viral load in the brain, and the innate immune response. The AD susceptibility gene cholesterol 25-hydroxylase (CH25H) is upregulated in the AD brain and is involved in the antiviral immune response. HSV-1 interacts with additional genes to affect cognition-related pathways and key enzymes involved in Aβ production, Aβ clearance, and hyperphosphorylation of tau proteins. Aβ itself functions as an antimicrobial peptide (AMP) against various pathogens including HSV-1. Evidence is presented supporting the hypothesis that Aβ is produced as an AMP in response to HSV-1 and other brain infections, leading to Aβ deposition and plaque formation in AD. Epidemiologic studies associating HSV-1 infection with AD and cognitive impairment are discussed. Studies are reviewed supporting subclinical chronic reactivation of latent HSV-1 in the brain as significant in the pathogenesis of AD. Finally, the rationale for and importance of clinical trials treating HSV-1-infected MCI and AD patients with antiviral medication is discussed.
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Affiliation(s)
- Steven A Harris
- St. Vincent Medical Group, Northside Internal Medicine, Indianapolis, IN, United States
| | - Elizabeth A Harris
- Department of Neurology, University of Chicago Medical Center, Chicago, IL, United States
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19
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Carter CJ. Genetic, Transcriptome, Proteomic, and Epidemiological Evidence for Blood-Brain Barrier Disruption and Polymicrobial Brain Invasion as Determinant Factors in Alzheimer's Disease. J Alzheimers Dis Rep 2017; 1:125-157. [PMID: 30480234 PMCID: PMC6159731 DOI: 10.3233/adr-170017] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Diverse pathogens are detected in Alzheimer's disease (AD) brains. A bioinformatics survey showed that AD genome-wide association study (GWAS) genes (localized in bone marrow, immune locations and microglia) relate to multiple host/pathogen interactomes (Candida albicans, Cryptococcus neoformans, Bornavirus, Borrelia burgdorferri, cytomegalovirus, Ebola virus, HSV-1, HERV-W, HIV-1, Epstein-Barr, hepatitis C, influenza, Chlamydia pneumoniae, Porphyrymonas gingivalis, Helicobacter pylori, Toxoplasma gondii, Trypanosoma cruzi). These interactomes also relate to the AD hippocampal transcriptome and to plaque or tangle proteins. Upregulated AD hippocampal genes match those upregulated by multiple bacteria, viruses, fungi, or protozoa in immunocompetent cells. AD genes are enriched in GWAS datasets reflecting pathogen diversity, suggesting selection for pathogen resistance, as supported by the old age of AD patients, implying resistance to earlier infections. APOE4 is concentrated in regions of high parasitic burden and protects against childhood tropical infections and hepatitis C. Immune/inflammatory gain of function applies to APOE4, CR1, and TREM2 variants. AD genes are also expressed in the blood-brain barrier (BBB), which is disrupted by AD risk factors (age, alcohol, aluminum, concussion, cerebral hypoperfusion, diabetes, homocysteine, hypercholesterolemia, hypertension, obesity, pesticides, pollution, physical inactivity, sleep disruption, smoking) and by pathogens, directly or via olfactory routes to basal-forebrain BBB control centers. The BBB benefits from statins, NSAIDs, estrogen, melatonin, memantine, and the Mediterranean diet. Polymicrobial involvement is supported by upregulation of bacterial, viral, and fungal sensors/defenders in the AD brain, blood, or cerebrospinal fluid. AD serum amyloid-β autoantibodies may attenuate its antimicrobial effects favoring microbial survival and cerebral invasion leading to activation of neurodestructive immune/inflammatory processes, which may also be augmented by age-related immunosenescence. AD may thus respond to antibiotic, antifungal, or antiviral therapy.
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Polymicrobial Infections In Brain Tissue From Alzheimer's Disease Patients. Sci Rep 2017; 7:5559. [PMID: 28717130 PMCID: PMC5514053 DOI: 10.1038/s41598-017-05903-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 06/05/2017] [Indexed: 01/10/2023] Open
Abstract
Several studies have advanced the idea that the etiology of Alzheimer’s disease (AD) could be microbial in origin. In the present study, we tested the possibility that polymicrobial infections exist in tissue from the entorhinal cortex/hippocampus region of patients with AD using immunohistochemistry (confocal laser scanning microscopy) and highly sensitive (nested) PCR. We found no evidence for expression of early (ICP0) or late (ICP5) proteins of herpes simplex virus type 1 (HSV-1) in brain sections. A polyclonal antibody against Borrelia detected structures that appeared not related to spirochetes, but rather to fungi. These structures were not found with a monoclonal antibody. Also, Borrelia DNA was undetectable by nested PCR in the ten patients analyzed. By contrast, two independent Chlamydophila antibodies revealed several structures that resembled fungal cells and hyphae, and prokaryotic cells, but most probably were unrelated to Chlamydophila spp. Finally, several structures that could belong to fungi or prokaryotes were detected using peptidoglycan and Clostridium antibodies, and PCR analysis revealed the presence of several bacteria in frozen brain tissue from AD patients. Thus, our results show that polymicrobial infections consisting of fungi and bacteria can be revealed in brain tissue from AD patients.
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McManus RM, Heneka MT. Role of neuroinflammation in neurodegeneration: new insights. ALZHEIMERS RESEARCH & THERAPY 2017; 9:14. [PMID: 28259169 PMCID: PMC5336609 DOI: 10.1186/s13195-017-0241-2] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Previously, the contribution of peripheral infection to cognitive decline was largely overlooked however, the past 15 years have established a key role for infectious pathogens in the progression of age-related neurodegeneration. It is now accepted that the immune privilege of the brain is not absolute, and that cells of the central nervous system are sensitive to both the inflammatory events occurring in the periphery and to the infiltration of peripheral immune cells. This is particularly relevant for the progression of Alzheimer’s disease, in which it has been demonstrated that patients are more vulnerable to infection-related cognitive changes. This can occur from typical infectious challenges such as respiratory tract infections, although a number of specific viral, bacterial, and fungal pathogens have also been associated with the development of the disease. To date, it is not clear whether these microorganisms are directly related to Alzheimer’s disease progression or if they are opportune pathogens that easily colonize those with dementia and exacerbate the ongoing inflammation observed in these individuals. This review will discuss the impact of each of these challenges, and examine the changes known to occur with age in the peripheral immune system, which may contribute to the age-related vulnerability to infection-induced cognitive decline.
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Affiliation(s)
- Róisín M McManus
- German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127, Bonn, Germany
| | - Michael T Heneka
- German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127, Bonn, Germany. .,Department of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127, Bonn, Germany.
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22
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Sochocka M, Zwolińska K, Leszek J. The Infectious Etiology of Alzheimer's Disease. Curr Neuropharmacol 2017; 15:996-1009. [PMID: 28294067 PMCID: PMC5652018 DOI: 10.2174/1570159x15666170313122937] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 03/06/2017] [Accepted: 03/06/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Inflammation is a part of the first line of defense of the body against invasive pathogens, and plays a crucial role in tissue regeneration and repair. A proper inflammatory response ensures the suitable resolution of inflammation and elimination of harmful stimuli, but when the inflammatory reactions are inappropriate it can lead to damage of the surrounding normal cells. The relationship between infections and Alzheimer's Disease (AD) etiology, especially lateonset AD (LOAD) has been continuously debated over the past three decades. METHODS This review discusses whether infections could be a causative factor that promotes the progression of AD and summarizes recent investigations associating infectious agents and chronic inflammation with AD. Preventive and therapeutic approaches to AD in the context of an infectious etiology of the disease are also discussed. RESULTS Emerging evidence supports the hypothesis of the role of neurotropic viruses from the Herpesviridae family, especially Human herpesvirus 1 (HHV-1), Cytomegalovirus (CMV), and Human herpesvirus 2 (HHV-2), in AD neuropathology. Recent investigations also indicate the association between Hepatitis C virus (HCV) infection and dementia. Among bacteria special attention is focused on spirochetes family and on periodontal pathogens such as Porphyromonas gingivalis or Treponema denticola that could cause chronic periodontitis and possibly contribute to the clinical onset of AD. CONCLUSION Chronic viral, bacterial and fungal infections might be causative factors for the inflammatory pathway in AD.
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Affiliation(s)
- Marta Sochocka
- Laboratory of Virology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Katarzyna Zwolińska
- Laboratory of Virology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Jerzy Leszek
- Department of Psychiatry, Wroclaw Medical University, Wroclaw, Poland
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23
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Ardura-Fabregat A, Boddeke EWGM, Boza-Serrano A, Brioschi S, Castro-Gomez S, Ceyzériat K, Dansokho C, Dierkes T, Gelders G, Heneka MT, Hoeijmakers L, Hoffmann A, Iaccarino L, Jahnert S, Kuhbandner K, Landreth G, Lonnemann N, Löschmann PA, McManus RM, Paulus A, Reemst K, Sanchez-Caro JM, Tiberi A, Van der Perren A, Vautheny A, Venegas C, Webers A, Weydt P, Wijasa TS, Xiang X, Yang Y. Targeting Neuroinflammation to Treat Alzheimer's Disease. CNS Drugs 2017; 31:1057-1082. [PMID: 29260466 PMCID: PMC5747579 DOI: 10.1007/s40263-017-0483-3] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Over the past few decades, research on Alzheimer's disease (AD) has focused on pathomechanisms linked to two of the major pathological hallmarks of extracellular deposition of beta-amyloid peptides and intra-neuronal formation of neurofibrils. Recently, a third disease component, the neuroinflammatory reaction mediated by cerebral innate immune cells, has entered the spotlight, prompted by findings from genetic, pre-clinical, and clinical studies. Various proteins that arise during neurodegeneration, including beta-amyloid, tau, heat shock proteins, and chromogranin, among others, act as danger-associated molecular patterns, that-upon engagement of pattern recognition receptors-induce inflammatory signaling pathways and ultimately lead to the production and release of immune mediators. These may have beneficial effects but ultimately compromise neuronal function and cause cell death. The current review, assembled by participants of the Chiclana Summer School on Neuroinflammation 2016, provides an overview of our current understanding of AD-related immune processes. We describe the principal cellular and molecular players in inflammation as they pertain to AD, examine modifying factors, and discuss potential future therapeutic targets.
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Affiliation(s)
- A. Ardura-Fabregat
- grid.5963.9Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany
| | - E. W. G. M. Boddeke
- 0000 0004 0407 1981grid.4830.fDepartment of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - A. Boza-Serrano
- 0000 0001 0930 2361grid.4514.4Experimental Neuroinflammation Laboratory, Department of Experimental Medical Sciences, Biomedical Centrum (BMC), Lund University, Lund, Sweden
| | - S. Brioschi
- grid.5963.9Department of Psychiatry and Psychotherapy, Medical Center University of Freiburg, Faculty of Medicine University of Freiburg, Freiburg, Germany
| | - S. Castro-Gomez
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - K. Ceyzériat
- grid.457334.2Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut de biologie François Jacob, MIRCen, 92260 Fontenay-aux-Roses, France ,0000 0001 2171 2558grid.5842.bNeurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, UMR 9199, F-92260 Fontenay-aux-Roses, France
| | - C. Dansokho
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany
| | - T. Dierkes
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany ,0000 0000 8786 803Xgrid.15090.3dBiomedical Centre, Institute of Innate Immunity, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - G. Gelders
- 0000 0001 0668 7884grid.5596.fDepartment of Neurosciences, Laboratory for Neurobiology and Gene Therapy, KU Leuven, Leuven, Belgium
| | - Michael T. Heneka
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany ,0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - L. Hoeijmakers
- 0000000084992262grid.7177.6Center for Neuroscience (SILS-CNS), Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - A. Hoffmann
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - L. Iaccarino
- grid.15496.3fVita-Salute San Raffaele University, Milan, Italy ,0000000417581884grid.18887.3eIn Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - S. Jahnert
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - K. Kuhbandner
- Department of Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - G. Landreth
- 0000 0001 2287 3919grid.257413.6Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202 USA
| | - N. Lonnemann
- 0000 0001 1090 0254grid.6738.aDepartment of Cellular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | | | - R. M. McManus
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany
| | - A. Paulus
- 0000 0001 0930 2361grid.4514.4Experimental Neuroinflammation Laboratory, Department of Experimental Medical Sciences, Biomedical Centrum (BMC), Lund University, Lund, Sweden
| | - K. Reemst
- 0000000084992262grid.7177.6Center for Neuroscience (SILS-CNS), Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - J. M. Sanchez-Caro
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany
| | - A. Tiberi
- grid.6093.cBio@SNS Laboratory, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - A. Van der Perren
- 0000 0001 0668 7884grid.5596.fDepartment of Neurosciences, Laboratory for Neurobiology and Gene Therapy, KU Leuven, Leuven, Belgium
| | - A. Vautheny
- grid.457334.2Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut de biologie François Jacob, MIRCen, 92260 Fontenay-aux-Roses, France ,0000 0001 2171 2558grid.5842.bNeurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, UMR 9199, F-92260 Fontenay-aux-Roses, France
| | - C. Venegas
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - A. Webers
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - P. Weydt
- 0000 0000 8786 803Xgrid.15090.3dDepartment of Neurodegenerative Disease and Gerontopsychiatry/Neurology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53127 Bonn, Germany
| | - T. S. Wijasa
- 0000 0004 0438 0426grid.424247.3German Center for Neurodegenerative Diseases (DZNE), Sigmund Freud Str. 27, 53127 Bonn, Germany
| | - X. Xiang
- 0000 0004 1936 973Xgrid.5252.0Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, Germany ,0000 0004 1936 973Xgrid.5252.0Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University, Munich, 82152 Munich, Germany
| | - Y. Yang
- 0000 0001 0930 2361grid.4514.4Experimental Neuroinflammation Laboratory, Department of Experimental Medical Sciences, Biomedical Centrum (BMC), Lund University, Lund, Sweden
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Pisa D, Alonso R, Rábano A, Horst MN, Carrasco L. Fungal Enolase, β-Tubulin, and Chitin Are Detected in Brain Tissue from Alzheimer's Disease Patients. Front Microbiol 2016; 7:1772. [PMID: 27872620 PMCID: PMC5097921 DOI: 10.3389/fmicb.2016.01772] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 10/21/2016] [Indexed: 12/17/2022] Open
Abstract
Recent findings provide evidence that fungal structures can be detected in brain tissue from Alzheimer’s disease (AD) patients using rabbit polyclonal antibodies raised against whole fungal cells. In the present work, we have developed and tested specific antibodies that recognize the fungal proteins, enolase and β-tubulin, and an antibody that recognizes the fungal polysaccharide chitin. Consistent with our previous studies, a number of rounded yeast-like and hyphal structures were detected using these antibodies in brain sections from AD patients. Some of these structures were intracellular and, strikingly, some were found to be located inside nuclei from neurons, whereas other fungal structures were detected extracellularly. Corporya amylacea from AD patients also contained enolase and β-tubulin as revealed by these selective antibodies, but were devoid of fungal chitin. Importantly, brain sections from control subjects were usually negative for staining with the three antibodies. However, a few fungal structures can be observed in some control individuals. Collectively, these findings indicate the presence of two fungal proteins, enolase and β-tubulin, and the polysaccharide chitin, in CNS tissue from AD patients. These findings are consistent with our hypothesis that AD is caused by disseminated fungal infection.
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Affiliation(s)
- Diana Pisa
- Centro de Biología Molecular "Severo Ochoa," Universidad Autónoma de Madrid Madrid, Spain
| | - Ruth Alonso
- Centro de Biología Molecular "Severo Ochoa," Universidad Autónoma de Madrid Madrid, Spain
| | - Alberto Rábano
- Department of Neuropathology and Tissue Bank, Unidad de Investigación Proyecto Alzheimer, Fundación CIEN, Instituto de Salud Carlos III Madrid, Spain
| | - Michael N Horst
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon GA, USA
| | - Luis Carrasco
- Centro de Biología Molecular "Severo Ochoa," Universidad Autónoma de Madrid Madrid, Spain
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25
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de Pedro-Cuesta J, Martínez-Martín P, Rábano A, Ruiz-Tovar M, Alcalde-Cabero E, Calero M. Etiologic Framework for the Study of Neurodegenerative Disorders as Well as Vascular and Metabolic Comorbidities on the Grounds of Shared Epidemiologic and Biologic Features. Front Aging Neurosci 2016; 8:138. [PMID: 27378910 PMCID: PMC4904010 DOI: 10.3389/fnagi.2016.00138] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/27/2016] [Indexed: 12/12/2022] Open
Abstract
Background: During the last two decades, protein aggregation at all organismal levels, from viruses to humans, has emerged from a neglected area of protein science to become a central issue in biology and biomedicine. This article constitutes a risk-based review aimed at supporting an etiologic scenario of selected, sporadic, protein-associated, i.e., conformational, neurodegenerative disorders (NDDs), and their vascular- and metabolic-associated ailments. Methods: A rationale is adopted, to incorporate selected clinical data and results from animal-model research, complementing epidemiologic evidences reported in two prior articles. Findings: Theory is formulated assuming an underlying conformational transmission mechanism, mediated either by horizontal transfer of mammalian genes coding for specific aggregation-prone proteins, or by xeno-templating between bacterial and host proteins. We build a few population-based and experimentally-testable hypotheses focusing on: (1) non-disposable surgical instruments for sporadic Creutzfeldt-Jakob disease (sCJD) and other rapid progressive neurodegenerative dementia (sRPNDd), multiple system atrophy (MSA), and motor neuron disease (MND); and (2) specific bacterial infections such as B. pertussis and E. coli for all forms, but particularly for late-life sporadic conformational, NDDs, type 2 diabetes mellitus (T2DM), and atherosclerosis where natural protein fibrils present in such organisms as a result of adaptation to the human host induce prion-like mechanisms. Conclusion: Implications for cohort alignment and experimental animal research are discussed and research lines proposed.
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Affiliation(s)
- Jesús de Pedro-Cuesta
- Department of Applied Epidemiology, National Center for Epidemiology, Carlos III Institute of HealthMadrid, Spain; Consortium for Biomedical Research in Neurodegenerative Diseases (CIBERNED), National Institute of Health Carlos IIIMadrid, Spain
| | - Pablo Martínez-Martín
- Department of Applied Epidemiology, National Center for Epidemiology, Carlos III Institute of HealthMadrid, Spain; Consortium for Biomedical Research in Neurodegenerative Diseases (CIBERNED), National Institute of Health Carlos IIIMadrid, Spain
| | - Alberto Rábano
- Alzheimer Disease Research Unit, CIEN Foundation, Queen Sofia Foundation Alzheimer Center Madrid, Spain
| | - María Ruiz-Tovar
- Department of Applied Epidemiology, National Center for Epidemiology, Carlos III Institute of HealthMadrid, Spain; Consortium for Biomedical Research in Neurodegenerative Diseases (CIBERNED), National Institute of Health Carlos IIIMadrid, Spain
| | - Enrique Alcalde-Cabero
- Department of Applied Epidemiology, National Center for Epidemiology, Carlos III Institute of HealthMadrid, Spain; Consortium for Biomedical Research in Neurodegenerative Diseases (CIBERNED), National Institute of Health Carlos IIIMadrid, Spain
| | - Miguel Calero
- Consortium for Biomedical Research in Neurodegenerative Diseases (CIBERNED), National Institute of Health Carlos IIIMadrid, Spain; Alzheimer Disease Research Unit, CIEN Foundation, Queen Sofia Foundation Alzheimer CenterMadrid, Spain; Chronic Disease Programme, Carlos III Institute of Health, MajadahondaMadrid, Spain
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26
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Severance EG, Gressitt KL, Stallings CR, Katsafanas E, Schweinfurth LA, Savage CL, Adamos MB, Sweeney KM, Origoni AE, Khushalani S, Leweke FM, Dickerson FB, Yolken RH. Candida albicans exposures, sex specificity and cognitive deficits in schizophrenia and bipolar disorder. NPJ SCHIZOPHRENIA 2016; 2:16018. [PMID: 27336058 PMCID: PMC4898895 DOI: 10.1038/npjschz.2016.18] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/24/2016] [Accepted: 03/24/2016] [Indexed: 12/26/2022]
Abstract
Immune aberrations in schizophrenia and bipolar disorder have led to the hypotheses that infectious agents or corresponding immune responses might contribute to psychiatric etiopathogeneses. We investigated case-control differences in exposure to the opportunistic fungal pathogen, Candida albicans, and examined associations with cognition, medication, lifestyle, and somatic conditions. We quantified C. albicans IgG antibodies in two cohorts totaling 947 individuals and evaluated odds ratios (OR) of exposure with psychiatric disorder using multivariate regressions. The case-control cohort included 261 with schizophrenia, 270 with bipolar disorder, and 277 non-psychiatric controls; the second included 139 with first-episode schizophrenia, 78 of whom were antipsychotic naive. No differences in C. albicans exposures were found until diagnostic groups were stratified by sex. In males, C. albicans seropositivity conferred increased odds for a schizophrenia diagnosis (OR 2.04-9.53, P⩽0.0001). In females, C. albicans seropositivity conferred increased odds for lower cognitive scores on Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) in schizophrenia (OR 1.12, P⩽0.004), with significant decreases on memory modules for both disorders (P⩽0.0007-0.03). C. albicans IgG levels were not impacted by antipsychotic medications. Gastrointestinal (GI) disturbances were associated with elevated C. albicans in males with schizophrenia and females with bipolar disorder (P⩽0.009-0.02). C. albicans exposure was associated with homelessness in bipolar males (P⩽0.0015). In conclusion, sex-specific C. albicans immune responses were evident in psychiatric disorder subsets. Inquiry regarding C. albicans infection or symptoms may expedite amelioration of this treatable comorbid condition. Yeast exposure as a risk factor for schizophrenia and its associated cognitive and GI effects require further investigation including the possible contribution of gut-brain mechanisms.
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Affiliation(s)
- Emily G Severance
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kristin L Gressitt
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Emily Katsafanas
- Sheppard Pratt Health System, Stanley Research Program, Baltimore, MD, USA
| | | | - Christina L Savage
- Sheppard Pratt Health System, Stanley Research Program, Baltimore, MD, USA
| | - Maria B Adamos
- Sheppard Pratt Health System, Stanley Research Program, Baltimore, MD, USA
| | - Kevin M Sweeney
- Sheppard Pratt Health System, Stanley Research Program, Baltimore, MD, USA
| | - Andrea E Origoni
- Sheppard Pratt Health System, Stanley Research Program, Baltimore, MD, USA
| | - Sunil Khushalani
- Sheppard Pratt Health System, Stanley Research Program, Baltimore, MD, USA
| | - F Markus Leweke
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Faith B Dickerson
- Sheppard Pratt Health System, Stanley Research Program, Baltimore, MD, USA
| | - Robert H Yolken
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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