Can mild cognitive impairment and Alzheimer's disease be diagnosed by monitoring a miRNA triad in the blood?

Objectively diagnosing age-related cognitive impairment (ACI), mild cognitive impairment (MCI), and early-stage Alzheimer's disease (AD) is a difficult task, as most cognitive impairment is clinically established via questionnaires, history, and physical examinations. A recent study has suggested that monitoring a miRNA triad, miR-181a-5p, miR-146a-5p, and miR-148a-3p can identify ACI and its progression to MCI and AD (Islam et al., EMBO Mol Med. 13: e14997, 2021). This commentary deliberates findings from this article, such as elevated levels of the miRNA triad in the brain impairing neural plasticity and cognitive function, the efficiency of measuring the miRNA triad in the circulating blood diagnosing MCI and AD, and the promise for improving cognitive function in MCI and AD by inhibiting this miRNA triad. Additional studies required prior to employing this miRNA triad in clinical practice are also discussed.