Serum expression levels of miRNA-29b and miRNA-99b in young adults with acute ischemic stroke: a prospective observational case–control study

Circulating microRNAs (miRNAs) have emerged as potential biomarkers for acute ischemic stroke (AIS), but their role in young adults remains unclear. To investigate serum miRNA-29b and miRNA-99b expression levels in young adults with AIS and their association with stroke severity. This prospective observational case–control study was conducted at a tertiary emergency department and included consecutive young adults aged 18–50 years presenting with AIS within 24 h of symptom onset, along with healthy controls frequency-matched according to age and sex. Serum miRNA-29b and miRNA-99b expression levels were quantified using quantitative real-time polymerase chain reaction. Biomarker expression levels were compared between patients and controls and further analyzed according to stroke severity, as determined by the National Institutes of Health Stroke Scale (NIHSS). Correlations between miRNA expression and NIHSS scores were also assessed. In total, 35 patients with AIS and 15 healthy controls were enrolled. Serum miRNA-29b and miRNA-99b levels did not differ significantly between patients and controls ( p = 0.271 and p = 0.824, respectively). Likewise, no significant differences were observed according to stroke severity, and neither of the serum miRNA levels correlated with NIHSS scores. Although patients with moderate-to-severe stroke had numerically lower ΔCt miRNA-99b values, corresponding to relatively higher miRNA-99b expression, this difference was not statistically significant ( p = 0.097). Admission serum miRNA-29b and miRNA-99b levels did not differ significantly between young adults with AIS and healthy controls and were not significantly associated with initial stroke severity. Further large-scale prospective studies are needed to clarify the role of circulating miRNAs as age-specific biomarkers in young-onset ischemic stroke. This study was not registered, as it was a non-interventional, observational case–control study rather than a clinical trial.