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Nazir S. Salivary biomarkers: The early diagnosis of Alzheimer's disease. Aging Med (Milton) 2024; 7:202-213. [PMID: 38725701 PMCID: PMC11077336 DOI: 10.1002/agm2.12282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 10/25/2023] [Accepted: 12/19/2023] [Indexed: 05/12/2024] Open
Abstract
The precise identification of Alzheimer's disease and other prevalent neurodegenerative diseases remains a difficult issue that requires the development of early detection of the disease and inexpensive biomarkers that can replace the present cerebrospinal fluid and imaging biomarkers. Blood biomarkers, such as amyloid and neurofilament light, have been emphasized as an important and practical tool in a testing or examination procedure thanks to advancements in ultra-sensitive detection techniques. Although saliva is not currently being researched for neurodegenerative diseases, it is an important source of biomarkers that can be used for the identification of diseases and has some advantages over other biofluids. While this may be true for most people, getting saliva from elderly people presents some significant challenges. In this overview, we will first discuss how saliva is created and how aging-related illnesses may affect the amount and kind of saliva produced. The findings support the use of salivary amyloid protein, tau species, and novel biomarkers in the diagnosis of Alzheimer's disease.
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Affiliation(s)
- Sophia Nazir
- Wolfson Nanomaterials and Devices Laboratory, School of Computing, Electronics and MathematicsPlymouth UniversityDevonUK
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Fan Z, Li Z, Zhao S, Chen Y, Su Y, Peng G, Luo B. Salivary Aβ 1-42 may be a quick-tested biomarker for clinical use in Alzheimer's disease: a meta-analysis. J Neurol 2023; 270:1945-1954. [PMID: 36562850 DOI: 10.1007/s00415-022-11509-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 11/26/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Alzheimer's disease (AD) is the most prevalent form of dementia among the aging population. Cumulative studies aim to find non-invasive biomarkers in the early stages of AD. Saliva can be obtained easily, and salivary biomarkers have been proven effective in detecting neurodegenerative diseases. To find effective biomarkers in saliva and to help the diagnosis of AD, we performed a meta-analysis focusing on the salivary biomarkers (β-amyloid 1-42 (Aβ1-42), total tau (t-tau), phosphorylated tau (p-tau) and acetylcholinesterase (AChE)) in AD. METHODS We conducted a systematic online search for eligible studies reporting data on salivary biomarkers reflecting Aβ1-42, t-tau, p-tau, and AChE in AD cohorts versus controls. Biomarkers' performance was assessed in a random-effects meta-analysis with the ratio of mean (RoM). RESULTS A total of thirteen studies were included in the meta-analysis, of them seven involved salivary Aβ1-42 (271 AD and 489 controls), five involved salivary t-tau (324 AD and 252 controls), four involved salivary p-tau (130 AD and 161 controls), and three involved salivary AChE (81 AD and 54 controls). AD showed significantly higher salivary Aβ1-42 levels than control (ROM = 1.90 (95% CI 1.28-2.81, P = 0.001), while AD and control did not differ significantly on salivary t-tau, p-tau and AChE (ROM = 0.94, 95% CI 0.67-1.31, P = 0.72; ROM = 0.91, 95% CI 0.56-1.45, P = 0.68; ROM = 0.83, 95% CI 0.24-2.88, P = 0.77; respectively). CONCLUSION The pooled results provide evidence that salivary Aβ1-42 may serve as a sensitive biomarker for AD; nevertheless, larger AD cohorts are required to further confirm the sensitivity and specificity of salivary Aβ1-42 for AD diagnosis.
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Affiliation(s)
- Ziqi Fan
- Department of Neurology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Zheyu Li
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Shuai Zhao
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Yanxing Chen
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Yujie Su
- Department of Neurology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Guoping Peng
- Department of Neurology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Benyan Luo
- Department of Neurology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China.
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Non-Invasive Nasal Discharge Fluid and Other Body Fluid Biomarkers in Alzheimer’s Disease. Pharmaceutics 2022; 14:pharmaceutics14081532. [PMID: 35893788 PMCID: PMC9330777 DOI: 10.3390/pharmaceutics14081532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/12/2022] [Accepted: 07/19/2022] [Indexed: 02/04/2023] Open
Abstract
The key to current Alzheimer’s disease (AD) therapy is the early diagnosis for prompt intervention, since available treatments only slow the disease progression. Therefore, this lack of promising therapies has called for diagnostic screening tests to identify those likely to develop full-blown AD. Recent AD diagnosis guidelines incorporated core biomarker analyses into criteria, including amyloid-β (Aβ), total-tau (T-tau), and phosphorylated tau (P-tau). Though effective, the accessibility of screening tests involving conventional cerebrospinal fluid (CSF)- and blood-based analyses is often hindered by the invasiveness and high cost. In an attempt to overcome these shortcomings, biomarker profiling research using non-invasive body fluid has shown the potential to capture the pathological changes in the patients’ bodies. These novel non-invasive body fluid biomarkers for AD have emerged as diagnostic and pathological targets. Here, we review the potential peripheral biomarkers, including non-invasive peripheral body fluids of nasal discharge, tear, saliva, and urine for AD.
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Pomilio AB, Vitale AA, Lazarowski AJ. Uncommon Noninvasive Biomarkers for the Evaluation and Monitoring of the Etiopathogenesis of Alzheimer's Disease. Curr Pharm Des 2022; 28:1152-1169. [DOI: 10.2174/1381612828666220413101929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 02/25/2022] [Indexed: 11/22/2022]
Abstract
Background:
Alzheimer´s disease (AD) is the most widespread dementia in the world, followed by vascular dementia. Since AD is a heterogeneous disease that shows several varied phenotypes, it is not easy to make an accurate diagnosis, so it arises when the symptoms are clear and the disease is already very advanced. Therefore, it is important to find out biomarkers for AD early diagnosis that facilitate treatment or slow down the disease. Classic biomarkers are obtained from cerebrospinal fluid and plasma, along with brain imaging by positron emission tomography. Attempts have been made to discover uncommon biomarkers from other body fluids, which are addressed in this update.
Objective:
This update aims to describe recent biomarkers from minimally invasive body fluids for the patients, such as saliva, urine, eye fluid or tears.
Methods:
Biomarkers were determined in patients versus controls by single tandem mass spectrometry, and immunoassays. Metabolites were identified by nuclear magnetic resonance, and microRNAs with genome-wide high-throughput real-time polymerase chain reaction-based platforms.
Results:
Biomarkers from urine, saliva, and eye fluid were described, including peptides/proteins, metabolites, and some microRNAs. The association with AD neuroinflammation and neurodegeneration was analyzed, highlighting the contribution of matrix metalloproteinases, the immune system and microglia, as well as the vascular system.
Conclusion:
Unusual biomarkers have been developed, which distinguish each stage and progression of the disease, and are suitable for the early AD diagnosis. An outstanding relationship of biomarkers with neuroinflammation and neurodegeneration was assessed, clearing up concerns of the etiopathogenesis of AD.
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Affiliation(s)
- Alicia B. Pomilio
- Departamento de Bioquímica Clínica, Área Hematología, Hospital de Clínicas “José de San Martín”, Universidad de Buenos Aires, Av. Córdoba 2351, C1120AAF Buenos Aires, Argentina
| | - Arturo A. Vitale
- Departamento de Bioquímica Clínica, Área Hematología, Hospital de Clínicas “José de San Martín”, Universidad de Buenos Aires, Av. Córdoba 2351, C1120AAF Buenos Aires, Argentina
| | - Alberto J. Lazarowski
- Departamento de Bioquímica Clínica, Facultad de Farmacia y Bioquímica, Instituto de Fisiopatología y Bioquímica Clínica (INFIBIOC), Universidad de Buenos Aires, Córdoba 2351, C1120AAF Buenos Aires, Argentina
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The Role of Salivary Biomarkers in the Early Diagnosis of Alzheimer's Disease and Parkinson's Disease. Diagnostics (Basel) 2021; 11:diagnostics11020371. [PMID: 33671562 PMCID: PMC7926361 DOI: 10.3390/diagnostics11020371] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/19/2021] [Accepted: 02/19/2021] [Indexed: 12/13/2022] Open
Abstract
Many neurodegenerative diseases present with progressive neuronal degeneration, which can lead to cognitive and motor impairment. Early screening and diagnosis of neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) are necessary to begin treatment before the onset of clinical symptoms and slow down the progression of the disease. Biomarkers have shown great potential as a diagnostic tool in the early diagnosis of many diseases, including AD and PD. However, screening for these biomarkers usually includes invasive, complex and expensive methods such as cerebrospinal fluid (CSF) sampling through a lumbar puncture. Researchers are continuously seeking to find a simpler and more reliable diagnostic tool that would be less invasive than CSF sampling. Saliva has been studied as a potential biological fluid that could be used in the diagnosis and early screening of neurodegenerative diseases. This review aims to provide an insight into the current literature concerning salivary biomarkers used in the diagnosis of AD and PD. The most commonly studied salivary biomarkers in AD are β-amyloid1-42/1-40 and TAU protein, as well as α-synuclein and protein deglycase (DJ-1) in PD. Studies continue to be conducted on this subject and researchers are attempting to find correlations between specific biomarkers and early clinical symptoms, which could be key in creating new treatments for patients before the onset of symptoms.
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Rastogi S, Sharma V, Bharti PS, Rani K, Modi GP, Nikolajeff F, Kumar S. The Evolving Landscape of Exosomes in Neurodegenerative Diseases: Exosomes Characteristics and a Promising Role in Early Diagnosis. Int J Mol Sci 2021; 22:E440. [PMID: 33406804 PMCID: PMC7795439 DOI: 10.3390/ijms22010440] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/23/2020] [Accepted: 12/30/2020] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases (ND) remains to be one of the biggest burdens on healthcare systems and serves as a leading cause of disability and death. Alzheimer's disease (AD) is among the most common of such disorders, followed by Parkinson's disease (PD). The basic molecular details of disease initiation and pathology are still under research. Only recently, the role of exosomes has been linked to the initiation and progression of these neurodegenerative diseases. Exosomes are small bilipid layer enclosed extracellular vesicles, which were once considered as a cellular waste and functionless. These nano-vesicles of 30-150 nm in diameter carry specific proteins, lipids, functional mRNAs, and high amounts of non-coding RNAs (miRNAs, lncRNAs, and circRNAs). As the exosomes content is known to vary as per their originating and recipient cells, these vesicles can be utilized as a diagnostic biomarker for early disease detection. Here we review exosomes, their biogenesis, composition, and role in neurodegenerative diseases. We have also provided details for their characterization through an array of available techniques. Their updated role in neurodegenerative disease pathology is also discussed. Finally, we have shed light on a novel field of salivary exosomes as a potential candidate for early diagnosis in neurodegenerative diseases and compared the biomarkers of salivary exosomes with other blood/cerebrospinal fluid (CSF) based exosomes within these neurological ailments.
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Affiliation(s)
- Simran Rastogi
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India; (S.R.); (V.S.); (P.S.B.)
| | - Vaibhav Sharma
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India; (S.R.); (V.S.); (P.S.B.)
| | - Prahalad Singh Bharti
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India; (S.R.); (V.S.); (P.S.B.)
| | - Komal Rani
- Department of Biotechnology, Amity University, Mumbai 410206, India;
| | - Gyan P. Modi
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India;
| | - Fredrik Nikolajeff
- Department of Health Science, Lulea Technical University, 97187 Lulea, Sweden
| | - Saroj Kumar
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India; (S.R.); (V.S.); (P.S.B.)
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Bălașa AF, Chircov C, Grumezescu AM. Body Fluid Biomarkers for Alzheimer's Disease-An Up-To-Date Overview. Biomedicines 2020; 8:E421. [PMID: 33076333 PMCID: PMC7602623 DOI: 10.3390/biomedicines8100421] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/09/2020] [Accepted: 10/13/2020] [Indexed: 02/06/2023] Open
Abstract
Neurodegeneration is a highly complex process which is associated with a variety of molecular mechanisms related to ageing. Among neurodegenerative disorders, Alzheimer's disease (AD) is the most common, affecting more than 45 million individuals. The underlying mechanisms involve amyloid plaques and neurofibrillary tangles (NFTs) deposition, which will subsequently lead to oxidative stress, chronic neuroinflammation, neuron dysfunction, and neurodegeneration. The current diagnosis methods are still limited in regard to the possibility of the accurate and early detection of the diseases. Therefore, research has shifted towards the identification of novel biomarkers and matrices as biomarker sources, beyond amyloid-β and tau protein levels within the cerebrospinal fluid (CSF), that could improve AD diagnosis. In this context, the aim of this paper is to provide an overview of both conventional and novel biomarkers for AD found within body fluids, including CSF, blood, saliva, urine, tears, and olfactory fluids.
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Affiliation(s)
- Adrian Florian Bălașa
- Târgu Mures, Emergency Clinical Hospital, “George Emil Palade” University of Medicine, Pharmacy, Science and Technology of Târgu Mures, RO-540142 Târgu Mures, Romania;
| | - Cristina Chircov
- Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, RO-060042 Bucharest, Romania;
| | - Alexandru Mihai Grumezescu
- Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, RO-060042 Bucharest, Romania;
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Ausó E, Gómez-Vicente V, Esquiva G. Biomarkers for Alzheimer's Disease Early Diagnosis. J Pers Med 2020; 10:E114. [PMID: 32899797 PMCID: PMC7563965 DOI: 10.3390/jpm10030114] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/27/2020] [Accepted: 09/01/2020] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, affecting the central nervous system (CNS) through the accumulation of intraneuronal neurofibrillary tau tangles (NFTs) and β-amyloid plaques. By the time AD is clinically diagnosed, neuronal loss has already occurred in many brain and retinal regions. Therefore, the availability of early and reliable diagnosis markers of the disease would allow its detection and taking preventive measures to avoid neuronal loss. Current diagnostic tools in the brain, such as magnetic resonance imaging (MRI), positron emission tomography (PET) imaging, and cerebrospinal fluid (CSF) biomarkers (Aβ and tau) detection are invasive and expensive. Brain-secreted extracellular vesicles (BEVs) isolated from peripheral blood have emerged as novel strategies in the study of AD, with enormous potential as a diagnostic evaluation of therapeutics and treatment tools. In addition; similar mechanisms of neurodegeneration have been demonstrated in the brain and the eyes of AD patients. Since the eyes are more accessible than the brain, several eye tests that detect cellular and vascular changes in the retina have also been proposed as potential screening biomarkers. The aim of this study is to summarize and discuss several potential markers in the brain, eye, blood, and other accessible biofluids like saliva and urine, and correlate them with earlier diagnosis and prognosis to identify individuals with mild symptoms prior to dementia.
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Affiliation(s)
| | | | - Gema Esquiva
- Department of Optics, Pharmacology and Anatomy, University of Alicante, 03690 Alicante, Spain; (E.A.); (V.G.-V.)
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Turner RS, Stubbs T, Davies DA, Albensi BC. Potential New Approaches for Diagnosis of Alzheimer's Disease and Related Dementias. Front Neurol 2020; 11:496. [PMID: 32582013 PMCID: PMC7290039 DOI: 10.3389/fneur.2020.00496] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 05/06/2020] [Indexed: 12/21/2022] Open
Abstract
Dementia is an umbrella term-caused by a large number of specific diagnoses, including several neurodegenerative disorders. Alzheimer's disease (AD) is now the most common cause of dementia in advanced countries, while dementia due to neurosyphilis was the leading cause a century ago. Many challenges remain for diagnosing dementia definitively. Some of these include variability of early symptoms and overlap with similar disorders, as well as the possibility of combined, or mixed, etiologies in some cases. Newer technologies, including the incorporation of PET neuroimaging and other biomarkers (genomics and proteomics), are being incorporated into revised diagnostic criteria. However, the application of novel diagnostic methods at clinical sites is plagued by many caveats including availability and access. This review surveys new diagnostic methods as well as remaining challenges-for clinical care and clinical research.
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Affiliation(s)
- R Scott Turner
- Department of Neurology, Georgetown University, Washington, DC, United States
| | - Terry Stubbs
- ActivMed, Practices & Research, Methuen, MA, United States
| | - Don A Davies
- Division of Neurodegenerative Disorders, St Boniface Hospital Research, University of Manitoba, Winnipeg, MB, Canada
| | - Benedict C Albensi
- Division of Neurodegenerative Disorders, St Boniface Hospital Research, University of Manitoba, Winnipeg, MB, Canada.,Department of Pharmacology & Therapeutics, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
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Paraskevaidi M, Allsop D, Karim S, Martin FL, Crean S. Diagnostic Biomarkers for Alzheimer's Disease Using Non-Invasive Specimens. J Clin Med 2020; 9:jcm9061673. [PMID: 32492907 PMCID: PMC7356561 DOI: 10.3390/jcm9061673] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 12/11/2022] Open
Abstract
Studies in the field of Alzheimer’s disease (AD) have shown the emergence of biomarkers in biologic fluids that hold great promise for the diagnosis of the disease. A diagnosis of AD at a presymptomatic or early stage may be the key for a successful treatment, with clinical trials currently investigating this. It is anticipated that preventative and therapeutic strategies may be stage-dependent, which means that they have a better chance of success at a very early stage—before critical neurons are lost. Several studies have been investigating the use of cerebrospinal fluid (CSF) and blood as clinical samples for the detection of AD with a number of established core markers, such as amyloid beta (Aβ), total tau (T-tau) and phosphorylated tau (P-tau), being at the center of clinical research interest. The use of oral samples—including saliva and buccal mucosal cells—falls under one of the least-investigated areas in AD diagnosis. Such samples have great potential to provide a completely non-invasive alternative to current CSF and blood sampling procedures. The present work is a thorough review of the results and analytical approaches, including proteomics, metabolomics, spectroscopy and microbiome analyses that have been used for the study and detection of AD using salivary samples and buccal cells. With a few exceptions, most of the studies utilizing oral samples were performed in small cohorts, which in combination with the existence of contradictory results render it difficult to come to a definitive conclusion on the value of oral markers. Proteins such as Aβ, T-tau and P-tau, as well as small metabolites, were detected in saliva and have shown some potential as future AD diagnostics. Future large-cohort studies and standardization of sample preparation and (pre-)analytical factors are necessary to determine the use of these non-invasive samples as a diagnostic tool for AD.
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Affiliation(s)
- Maria Paraskevaidi
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, UK; (F.L.M.); (S.C.)
- Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, UK
- Correspondence: ; Tel.: +44-074-7900-6626
| | - David Allsop
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YW, UK;
| | - Salman Karim
- Central Lancashire Memory Assessment Service, Lancashire Care NHS Foundation Trust, Bamber Bridge, Preston PR5 6YA, UK;
| | - Francis L. Martin
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, UK; (F.L.M.); (S.C.)
| | - StJohn Crean
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, UK; (F.L.M.); (S.C.)
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Salivary Redox Biomarkers in Selected Neurodegenerative Diseases. J Clin Med 2020; 9:jcm9020497. [PMID: 32059422 PMCID: PMC7074092 DOI: 10.3390/jcm9020497] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/10/2020] [Accepted: 02/10/2020] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases (NDDs), such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, are disorders, which cause irreversible and progressive deterioration of the central nervous system. The pathophysiology of NDDs is still not fully explained; nevertheless, oxidative stress is considered as a critical mediator of cerebral degeneration, brain inflammation, as well as neuronal apoptosis. Therefore, it is not surprising that redox biomarkers are increasingly used in the diagnosis of neurodegenerative diseases. As saliva is a very easy to obtain bioliquid, it seems promising to use this biomaterial in the diagnosis of NDDs. Saliva collection is easy, cheap, stress-free, and non-infectious, and it does not require the help of a specialised medical personnel. Additionally, the concentrations of many salivary redox biomarkers correlate with their content in blood serum as well as the degree of disease progression, which makes them non-invasive indicators of NDDs. This paper reviews the latest knowledge concerning the use of salivary redox biomarkers in the diagnosis and prognosis of selected neurodegenerative diseases.
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Ashton NJ, Ide M, Zetterberg H, Blennow K. Salivary Biomarkers for Alzheimer's Disease and Related Disorders. Neurol Ther 2019; 8:83-94. [PMID: 31833026 PMCID: PMC6908535 DOI: 10.1007/s40120-019-00168-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Indexed: 12/13/2022] Open
Abstract
The search for accessible and cost-effective biomarkers to complement current cerebrospinal fluid (CSF) and imaging biomarkers in the accurate detection of Alzheimer disease (AD) and other common neurodegenerative disorders remains a challenging task. The advances in ultra-sensitive detection methods has highlighted blood biomarkers (e.g. amyloid-β and neurofilament light) as a valuable and realistic tool in a diagnostic or screening process. Saliva, however, is also a rich source of potential biomarkers for disease detection and offers several practical advantages over biofluids that are currently examined for neurodegenerative disorders. However, while this may be true for the general population, challenges in collecting saliva from an elderly population should be seriously considered. In this review, we begin by discussing how saliva is produced and how age-related conditions can modify saliva production and composition. We then focus on the data available which support the concept of salivary amyloid-β, tau species and novel biomarkers in detecting AD and alpha-synuclein (α-syn) in Parkinson's disease (PD).
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Affiliation(s)
- Nicholas J Ashton
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden.
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Institute Clinical Neuroscience Institute, London, UK.
- NIHR Biomedical Research Centre for Mental Health and Biomedical Research Unit for Dementia at South London and Maudsley NHS Foundation, London, UK.
| | - Mark Ide
- Periodontology, Centre for Host Microbiome Interactions, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, UK
- Mucosal and Salivary Biology, Centre for Host Microbiome Interactions, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, UK
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, London, UK
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
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Biomarkers for Alzheimer's Disease in Saliva: A Systematic Review. DISEASE MARKERS 2019; 2019:4761054. [PMID: 31191751 PMCID: PMC6525835 DOI: 10.1155/2019/4761054] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/04/2019] [Indexed: 12/13/2022]
Abstract
Background The histopathological changes of Alzheimer's disease (AD) are detectable decades prior to its clinical expression. However, there is a need for an early, inexpensive, noninvasive diagnostic biomarker to detect specific Alzheimer pathology. Recently developed neuroimaging biomarkers show promising results, but these methods are expensive and cause radiation. Furthermore, the analysis of cerebrospinal fluid (CSF) biomarkers requires an invasive lumbar puncture. Saliva is an easily obtained body fluid, and a stable saliva biomarker would therefore be a promising candidate for a future method for diagnosing AD. The purpose of this systematic review was to investigate studies of biomarkers in saliva samples for the diagnosis of AD. Methods The included articles were identified through a literature search in PubMed and Google Scholar for all articles until November 1st, 2018, and furthermore, all reference lists of included articles were reviewed by hand. We included articles written in English investigating saliva from patients with AD and a control group. Results A total of 65 studies were identified, whereof 16 studies met the inclusion criteria and were included in the systematic review. A plethora of different biomarkers were investigated, and ten out of the sixteen studies showed a statistical significance in biomarkers between patients with AD and healthy, elderly controls, among these biomarkers for specific AD pathology (amyloid beta 1-42 (Aβ42) and tau). Conclusion Aβ42 and tau seem to be worthy candidates for future salivary biomarkers for AD, but other biomarkers such as lactoferrin and selected metabolites also have potential. More studies must be carried out with larger sample sizes and a standardization of the sampling and processing method. Factors such as diurnal variation, AD patients' decreased ability of oral self-care, and salivary flowrates must be taken into consideration.
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Farah R, Haraty H, Salame Z, Fares Y, Ojcius DM, Said Sadier N. Salivary biomarkers for the diagnosis and monitoring of neurological diseases. Biomed J 2018; 41:63-87. [PMID: 29866603 PMCID: PMC6138769 DOI: 10.1016/j.bj.2018.03.004] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 03/13/2018] [Accepted: 03/29/2018] [Indexed: 12/17/2022] Open
Abstract
Current research efforts on neurological diseases are focused on identifying novel disease biomarkers to aid in diagnosis, provide accurate prognostic information and monitor disease progression. With advances in detection and quantification methods in genomics, proteomics and metabolomics, saliva has emerged as a good source of samples for detection of disease biomarkers. Obtaining a sample of saliva offers multiple advantages over the currently tested biological fluids as it is a non-invasive, painless and simple procedure that does not require expert training or harbour undesirable side effects for the patients. Here, we review the existing literature on salivary biomarkers and examine their validity in diagnosing and monitoring neurodegenerative and neuropsychiatric disorders such as autism and Alzheimer's, Parkinson's and Huntington's disease. Based on the available research, amyloid beta peptide, tau protein, lactoferrin, alpha-synuclein, DJ-1 protein, chromogranin A, huntingtin protein, DNA methylation disruptions, and micro-RNA profiles provide display a reliable degree of consistency and validity as disease biomarkers.
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Affiliation(s)
- Raymond Farah
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - Hayat Haraty
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - Ziad Salame
- Research Department, Faculty of Dental Medicine, Lebanese University, Beirut, Lebanon
| | - Youssef Fares
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - David M Ojcius
- Department of Biomedical Sciences, University of the Pacific, Arthur Dugoni School of Dentistry, San Francisco, CA, USA.
| | - Najwane Said Sadier
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon.
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Gozes I. Specific protein biomarker patterns for Alzheimer's disease: improved diagnostics in progress. EPMA J 2017; 8:255-259. [PMID: 29021836 DOI: 10.1007/s13167-017-0110-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/10/2017] [Indexed: 12/12/2022]
Abstract
This short review looks at Alzheimer's disease (AD) diagnosis through my own point of view, going from imaging through cerebrospinal fluid to blood proteins. Over the last couple of years, we have published two papers targeted at Alzheimer's diagnosis. In one paper, we took an approach of selecting a specific target, namely, activity-dependent neuroprotective protein (ADNP), and our results tightened the association of ADNP blood expression with intelligence. In another paper, we took an unbiased approach of analysis of all genes expressed in lymphoblastoid cells lines and discovered changes in expression of the regulator of G-protein signaling 2 (RGS2) as a potential AD predictor. This review will assess our data in comparison to selected independent studies focusing on blood protein biomarkers as well as assessing saliva and urine samples with potential predictive value for AD. Furthermore, the review will provide directions for a combination of innovative markers, stratifying the population toward disease prevention and personalized medicine.
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Affiliation(s)
- Illana Gozes
- The Lily and Avraham Gildor Chair for the Investigation of Growth Factors, Elton Laboratory for Neuroendocrinology, Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Adams Super Center for Brain Studies and Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel
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