MicroRNAs and mild cognitive impairment: A systematic review

Area of Science:

• Biomarkers
• Neuroscience
• Molecular Biology

Background:

• Mild cognitive impairment (MCI) represents a transitional stage between normal cognition and dementia.
• Accurate identification of individuals at high risk of progressing from MCI to Alzheimer's disease (AD) is crucial for effective management.
• Current MCI diagnosis relies on clinical assessment, with research biomarkers often requiring invasive procedures like cerebrospinal fluid (CSF) collection.

Purpose of the Study:

• To systematically review existing literature on the application of microRNAs (miRNAs) as biomarkers for diagnosing MCI.
• To assess the current evidence regarding the utility of miRNAs in identifying individuals with MCI.

Main Methods:

• A systematic literature search was conducted across PubMed, ISI Web of Knowledge, and Cochrane Database up to June 2018.
• Inclusion criteria focused on studies investigating microRNAs (miRNAs) in the context of MCI diagnosis.
• Methodological quality of included studies was evaluated using QUADAS-2 and QUIPS tools.

Main Results:

• Twenty-one studies involving 153 articles met the inclusion criteria, with participant numbers ranging from 6 to 330.
• Over 40 microRNAs (miRNAs) were identified as dysregulated in MCI.
• miR-206 was the only miRNA consistently found to be differentially expressed in MCI patients across multiple studies, though results require independent validation and show inconsistencies.

Conclusions:

• MicroRNAs (miRNAs) present a promising avenue for developing non-invasive biomarkers for mild cognitive impairment (MCI).
• Significant inconsistencies exist among current studies regarding miRNA expression in MCI, potentially due to variations in participant selection, sample handling, and analytical methods.
• Further research with standardized protocols and independent validation is necessary to establish the reliability of miRNAs as diagnostic biomarkers for MCI.