miR-146a Plasma Levels Are Not Altered in Alzheimer’s Disease but Correlate With Age and Illness Severity

miR-146a is a microRNA (miRNA) involved in neuroinflammation and aging; alterations in its expression were described in Alzheimer’s disease (AD). However, most of the studies conducted so far on this miRNA included a limited number of participants and produced contradictory results. We compared miR-146a levels in plasma from 33 AD patients vs. 28 age-matched non-affected controls (CTRL) through quantitative real-time polymerase chain reaction (qRT-PCR). No difference between the case and the control group was evidenced, but a correlation was detected between miR-146a levels and subjects’ age (p < 0.001) as well as between miR-146a levels and patients’ Mini-Mental State Examination (MMSE) scores (p = 0.011), in an enlarged group of 51 AD patients and 45 CTRL supporting a role for this miRNA in aging processes and disease progression.