Diagnostic performance of miR-21, miR-124, miR-132, and miR-200b serums in post-stroke cognitive impairment patients

Introduction
The diagnosis of post-stroke cognitive impairment (PSCI) mainly depends on neuro-psychological evaluation. It still lacks a sensitive and objective diagnostic biomarker. MicroRNAs (miRNAs, miRs) are novel and potential disease biomarkers. Our aim was to detect which specific miRNA is a good diagnostic biomarker for PSCI.

Material and methods
There were 77 first-ever stroke patients enrolled. Blood samples were collected at 14 days after stroke. Level of serum miR-21, miR-124, miR-132, and miR-200b were determined by quantitative polymerase chain reaction. Mini-mental state examination (MMSE) scale was used to measure the cognitive function of patients. Factional anisotropy (FA) score of diffusion tensor imaging was applied to detect the alteration of white matter. In addition, the relationship between miRNA level and cognitive status was further explored by correlation analysis.

Results
Finally, 45 PSCI and 32 post-stroke cognitive normality (PSCN) patients were enrolled. The expression of miR-21, miR-132, and miR-200b in PSCI patients was higher than in PSCN patients. In particular, the miR-21 level was substantially correlated with MMSE scores (r = 0.752, p < 0.001) and FA value (r = 0.636, p < 0.001). Additionally, the diagnostic performance of miR-21 alone or the combination of miR-21 and FA values performed well.

Conclusions
The miR-21 alone or combination of miR-21 and FA values are valuable diagnostic biomarkers in discriminating PSCI from PSCN.