Expression of microRNA‑222 in serum of patients with Alzheimer's disease.

The aim of the present study was to determine the association between Alzheimer's disease (AD) and microRNA‑222 in the serum of patients with AD. The expression of microRNAs was detected and the results were verified using microarray analysis and reverse transcription‑quantitative polymerase chain reaction. The results indicated that there were 35 strips of microRNA in the mild AD group, in which the difference of expression signal was >500 IU/ml. There were 26 strips of microRNA with a difference in expression signal of >500 IU/ml in the mild and moderate AD groups. The downregulation of microRNA‑222 in the mild and moderate groups was statistically significant (P<0.01), and the expression of microRNA‑222 in the moderate group was significantly lower, compared with that in the mild AD group (P<0.05). It was concluded that microRNA‑222 may affect the occurrence and development of AD through a variety of mechanisms, and may serve as a biomarker for the early diagnosis of AD.