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Publications

Journal Article Review Epublish

PubMed: 41767157 DOI: 10.1002/dad2.70268

Tears as a window to Alzheimer's disease: A systematic review of biomarkers for early detection.

Alzheimers Dement (Amst) 18(1):e70268

Authors: Inés López-Cuenca, Rubén Masa-Castro, Yael Hoz-Ruiz, Lidia Sánchez-Puebla, Lorena Elvira Hurtado, Elena Salobrar-García, José A Matamoros, José A Fernández-Albarral, Hector Leal-Lassalle, Juan J Salazar, Ana I Ramírez, José M Ramírez, Rosa de Hoz

Affiliations

  • Ramon Castroviejo Institute for Ophthalmic Research Complutense University of Madrid Madrid Spain.
  • Health Research Institute of the Hospital Clínico San Carlos (IdISSC) Madrid Spain.
  • Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry Complutense University of Madrid Madrid Spain.
  • Department of Immunology, Ophthalmology and ORL, School of Medicine Universidad Complutense de Madrid Madrid Spain.
  • Ramon Castroviejo Institute for Ophthalmic Research Complutense University of Madrid Madrid Spain. Health Research Institute of the Hospital Clínico San Carlos (IdISSC) Madrid Spain.
  • Ramon Castroviejo Institute for Ophthalmic Research Complutense University of Madrid Madrid Spain. Health Research Institute of the Hospital Clínico San Carlos (IdISSC) Madrid Spain. Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry Complutense University of Madrid Madrid Spain.

Abstract

Alzheimer's disease (AD) is the leading cause of dementia, characterized by the accumulation of amyloid beta and tau proteins, leading to neuronal degeneration and brain atrophy. While cerebrospinal fluid and blood biomarkers have advanced early AD diagnosis, these methods are invasive and costly. This systematic review investigates tears as a non-invasive, accessible source of AD biomarkers. Using tears, directly linked to the central nervous system, we can effectively detect proteins, microRNA (miRNA), and extracellular vesicles (EVs), reflecting neurodegenerative processes. Tear collection is cost effective and minimally stressful, allowing continuous biomarker monitoring across disease stages. This review highlights recent findings on specific proteins, miRNA, and EVs in tears of patients with AD, and examines tear collection and analysis methods. The potential of these techniques for early, accessible disease detection is emphasized. Further research is needed to standardize methods and validate biomarkers in larger cohorts, positioning tears as a valuable tool for early AD diagnosis and management.

MeSH

Extracellular Vesicles, Tears, Alzheimer Disease, Micrornas, Biomarkers, Diagnosis