Identification of Diagnosis Biomarkers in the Tears of Alzheimer's Disease Patients: The COG-EYE Pilot Study

Condition(s) studied

Investigational drug(s) / intervention(s)

Basal tear collection for the analysis of metabo-lipidomic profiles and concentrations of protein biomarkers (Tau, phosphorylated Tau, Aβ 1-40, and Aβ 1-42): Collection of a tear volume of (i) 2 x 5µL using glass microcapillary tubes and (ii) 12µL using Schirmer strips after the instillation of anesthetic eye drops for metabo-lipidomic analysis and multiplexing of protein markers

Collection of a blood sample (5 mL) for blood biomarkers analysis: Collection of a blood sample (5 mL) for blood biomarkers analysis.

Study summary

The diagnosis of Alzheimer's disease (AD) relies on the detection of protein biomarkers, particularly in cerebrospinal fluid (e.g., Aβ and phosphorylated Tau) or through brain imaging. The invasive nature of lumbar puncture and the numerous contraindications have driven the search for early and reliable diagnostic biomarkers for AD.

Human tears are an accessible biological fluid that has proven relevant in the biomarker search strategy for both ophthalmological and systemic diseases, especially neurodegenerative conditions. Advances in methods for low-volume analysis have facilitated the identification of tear biomarkers. Total tau has been reported as elevated in the tears of patients with AD compared to controls (n=65). Additionally, metabo-lipidomic analyses offer several advantages (accessibility, non-invasiveness, reproducibility) and also appear promising as a diagnostic tool for systemic and neurodegenerative diseases, such as amyotrophic lateral sclerosis. This supports the relevance of comparing both AD proteins biomarkers and metabo-lipidomic signatures in the tears of patients with AD (Mild Cognitive Impairement (MCI) and dementia) with healthy controls.

Eligibility

Primary outcome measure(s)

• Concentration of total Tau proteins in basal tears of patients with AD vs healthy volunteers — At inclusion
  12μL of tears will be collected using Schirmer strips after instillation of an anaesthetic eye drop. A multiplex analysis for the detection of protein of interest
• Concentration of phosphorylated Tau proteins in basal tears of patients with AD vs healthy volunteers — At inclusion
  12μL of tears will be collected using Schirmer strips after instillation of an anaesthetic eye drop. A multiplex analysis for the detection of protein of interest
• Concentration of Amyloid β 1-40 proteins in basal tears of patients with AD vs healthy volunteers — At inclusion
  12μL of tears will be collected using Schirmer strips after instillation of an anaesthetic eye drop. A multiplex analysis for the detection of protein of interest
• Concentration of Amyloid β 1-42 in basal tears of patients with AD vs healthy volunteers — At inclusion
  12μL of tears will be collected using Schirmer strips after instillation of an anaesthetic eye drop. A multiplex analysis for the detection of protein of interest
• Lipids in basal tears of patients with AD vs healthy volunteers — At inclusion
  Collection of tears (5μL) using a glass micropipette without local anaesthetic. Lipids in tears of patients with AD vs healthy volunteers
• Metabolites in basal tears of patients with AD vs healthy volunteers — At inclusion
  Collection of tears (5μL) using a glass micropipette without local anaesthetic. Metabolites in tears of patients with AD vs healthy volunteers

Trial sites (1)

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