Validation of microRNAs in Cerebrospinal Fluid as Biomarkers for Different Forms of Dementia in a Multicenter Study

Area of Science:

• Neuroscience
• Biochemistry
• Genetics

Background:

• MicroRNAs (miRNAs) are regulators of protein translation and are found in bodily fluids like cerebrospinal fluid (CSF).
• Specific miRNAs (miR-146a, miR-29a, miR-125b) previously showed differential expression in the CSF of Alzheimer's disease (AD) patients.
• CSF miRNAs are potential biomarkers for neurodegenerative diseases.

Purpose of the Study:

• To validate previous findings of differential miRNA expression in AD patients' CSF using larger, independent cohorts from multiple centers.
• To identify and address confounding factors inherent in multicenter studies of CSF biomarkers.
• To investigate miRNA expression in mild cognitive impairment (MCI) due to AD, frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB).

Main Methods:

• Utilized larger, independent sample cohorts from three distinct centers for validation.
• Included patients with AD, MCI due to AD, FTD, and DLB, alongside controls.
• Performed statistical analysis to identify and control for confounding factors in multicenter data.

Main Results:

• Confirmation of decreased miR-146a levels in AD patients compared to controls was achieved in one center.
• Identification of several confounding factors when combining data from all three centers.
• After controlling for identified confounding factors, no significant differences in miRNA levels were found between patient groups and controls.

Conclusions:

• Multicenter validation of specific miRNA levels in CSF for AD diagnosis is complex due to confounding factors.
• Previous findings of differential miRNA expression in AD CSF could not be replicated across combined cohorts after controlling for confounders.
• Recommendations are provided to mitigate pitfalls in future CSF miRNA measurement studies to enhance reliability and reproducibility.