PSALIVARY BIOMARKERS IN ALZHEIMER’S DISEASE: A NON-INVASIVE APPROACH FOR SCREENING
DOI:
https://doi.org/10.56238/arev7n11-197Keywords:
Alzheimer’s Disease, Saliva, Biomarkers, Β-Amyloid, Phosphorylated Tau, Early Detection, Non-Invasive DiagnosticsAbstract
Objective: The aim of this review is to summarize current evidence on salivary biomarkers, including β-amyloid42, phosphorylated tau (p-tau), and acetylcholinesterase, for the early detection and non-invasive screening of Alzheimer’s disease (AD).
Methodology: A comprehensive literature search was conducted using PubMed, Scopus, and Web of Science for studies published up to 2025. Keywords included “saliva,” “Alzheimer’s disease,” “β-amyloid,” “tau,” “acetylcholinesterase,” and “biomarkers.” Inclusion criteria focused on human studies reporting salivary biomarkers relevant to AD. Data were extracted regarding biomarker type, detection method, patient population, and main findings, and then synthesized to assess the diagnostic potential of saliva in AD screening.
Results: Studies consistently report elevated levels of β-amyloid42 and phosphorylated tau in the saliva of AD patients, reflecting neurodegenerative processes occurring in the brain. Altered salivary acetylcholinesterase activity has also been observed, suggesting potential diagnostic and therapeutic applications. Emerging evidence indicates that other molecules, such as lactoferrin and inflammatory proteins, may further enhance the predictive value of salivary assays. Saliva offers a non-invasive, cost-effective, and patient-friendly medium for repeated measurements, providing an accessible alternative to cerebrospinal fluid and neuroimaging methods. However, variability in collection protocols, small cohort sizes, and limited standardization remain significant challenges.
Conclusion: Salivary biomarkers represent a promising tool for the early detection and screening of Alzheimer’s disease. β-Amyloid42, phosphorylated tau, and acetylcholinesterase in saliva mirror central pathological processes and could facilitate timely diagnosis and preventive intervention. Future research should focus on standardizing collection and assay protocols, validating findings in larger populations, and integrating salivary biomarkers into routine clinical practice to improve early AD detection and patient outcomes.
Downloads
References
Ashraf, M., Sheikh, I., & Ashraf, M. (2025). Salivary biomarkers in Alzheimer’s. British Dental Journal, 239(4), 231–232. https://doi.org/10.1038/s41415-025-9130-4 DOI: https://doi.org/10.1038/s41415-025-9130-4
Carro, E., Bartolomé, F., & Bermejo-Pareja, F. (2024). Saliva as a diagnostic fluid for Alzheimer’s disease: From proteomics to clinical application. Frontiers in Aging Neuroscience, 16, 1354212. https://doi.org/10.3389/fnagi.2024.1354212
Goldoni, R., Dolci, C., Boccalari, E., et al. (2022). Salivary biomarkers of neurodegenerative and demyelinating diseases and biosensors for their detection. Ageing Research Reviews, 82, 101587. https://doi.org/10.1016/j.arr.2022.101587 DOI: https://doi.org/10.1016/j.arr.2022.101587
Grant, M. J., & Booth, A. (2009). A typology of reviews: An analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91–108. https://doi.org/10.1111/j.1471-1842.2009.00848.x DOI: https://doi.org/10.1111/j.1471-1842.2009.00848.x
Hampel, H., Cummings, J., & Blennow, K. (2018). Developing the next generation of Alzheimer’s disease therapeutics through the amyloid and cholinergic pathways. Nature Reviews Neurology, 14(11), 657–673. https://doi.org/10.1038/s41582-018-0076-4
Hampel, H., Toschi, N., Baldacci, F., et al. (2021). Alzheimer’s disease biomarker-guided diagnostic workflow using the AT(N) framework. Nature Reviews Neurology, 17(9), 577–589. https://doi.org/10.1038/s41582-021-00541-3 DOI: https://doi.org/10.1038/s41582-021-00520-w
Moola, S., Munn, Z., Tufanaru, C., et al. (2020). Chapter 7: Systematic reviews of etiology and risk. In JBI Manual for Evidence Synthesis. JBI. https://doi.org/10.46658/JBIMES-20-08 DOI: https://doi.org/10.46658/JBIRM-17-06
Nijakowski, K., Owecki, W., Jankowski, J., & Surdacka, A. (2024). Salivary biomarkers for Alzheimer’s disease: A systematic review with meta-analysis. International Journal of Molecular Sciences, 25(2), 1168. https://doi.org/10.3390/ijms25021168 DOI: https://doi.org/10.3390/ijms25021168
Page, M. J., McKenzie, J. E., Bossuyt, P. M., et al. (2021). The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. BMJ, 372, n71. https://doi.org/10.1136/bmj.n71 DOI: https://doi.org/10.1136/bmj.n71
Palmqvist, S., Janelidze, S., Quiroz, Y. T., et al. (2020). Discriminative accuracy of plasma phospho-tau217 for Alzheimer disease vs other neurodegenerative disorders. JAMA, 324(8), 772–781. https://doi.org/10.1001/jama.2020.12134 DOI: https://doi.org/10.1001/jama.2020.12134
Querfurth, H. W., & LaFerla, F. M. (2010). Alzheimer’s disease. New England Journal of Medicine, 362(4), 329–344. https://doi.org/10.1056/NEJMra0909142 DOI: https://doi.org/10.1056/NEJMra0909142
Tvarijonaviciute, A., Martínez-Subiela, S., & Cerón, J. J. (2020). Saliva as a diagnostic tool in human and veterinary medicine: A comprehensive review. Journal of Clinical Medicine, 9(5), 1522. https://doi.org/10.3390/jcm9051522 DOI: https://doi.org/10.3390/jcm9051522
World Health Organization. (2023). Global status report on the public health response to dementia 2023. WHO Press.
