Serum miRNA-29b and miRNA-99b show no clear link to stroke in young adults

Two circulating microRNAs that have attracted attention as possible biomarkers for acute ischemic stroke did not perform as expected in young adults, according to a prospective observational case-control study published in BMC Neurology. The study, conducted at a tertiary emergency department, measured serum miRNA-29b and miRNA-99b in young adults who presented with acute ischemic stroke within 24 hours of symptom onset and compared the results with those of healthy controls.

The researchers enrolled 35 patients with acute ischemic stroke aged 18 to 50 years, along with 15 healthy controls who were frequency-matched to the patients by age and sex. Serum levels of the two microRNAs were quantified using quantitative real-time polymerase chain reaction. The team then compared expression levels between patients and controls, analyzed them according to stroke severity as measured by the National Institutes of Health Stroke Scale, and assessed correlations between microRNA expression and NIHSS scores.

The results were negative on both counts. Serum miRNA-29b levels did not differ significantly between patients and controls (p = 0.271), and neither did miRNA-99b levels (p = 0.824). No significant differences were observed according to stroke severity, and neither microRNA correlated with NIHSS scores. One pattern did emerge in the data: patients with moderate-to-severe stroke had numerically lower ΔCt values for miRNA-99b, which corresponds to relatively higher expression of that microRNA. However, this difference did not reach statistical significance (p = 0.097), and the authors treat it as a signal that requires further investigation rather than a finding.

The study’s conclusion is straightforward: admission serum miRNA-29b and miRNA-99b levels did not differ significantly between young adults with acute ischemic stroke and healthy controls, and were not significantly associated with initial stroke severity. The authors note that circulating microRNAs have emerged as potential biomarkers for acute ischemic stroke, but that their role in young adults remains unclear, and they call for further large-scale prospective studies to clarify whether circulating microRNAs could serve as age-specific biomarkers in young-onset ischemic stroke.

Several limitations are worth keeping in view when interpreting these results. The sample size was small, with only 35 patients and 15 controls, which limits the statistical power to detect modest differences between groups; the suggestive but non-significant trend in miRNA-99b among patients with moderate-to-severe stroke illustrates how a larger cohort might resolve such questions. The study was a non-interventional, observational case-control study rather than a clinical trial, and it was not registered as a trial for that reason. The findings apply to young adults aged 18 to 50 presenting within 24 hours of symptom onset at a single tertiary emergency department, and the measurements reflect admission serum levels only. Within those boundaries, the study provides a cautious, evidence-based answer to a question that has been open in the literature: in this young patient group, these two microRNAs, at least as measured at admission, did not distinguish stroke patients from healthy controls or track the severity of the initial deficit.

Subject of Research: Serum miRNA-29b and miRNA-99b levels in young adults with acute ischemic stroke

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

Article References: Kaan, S., Az, A., Sogut, O., & Dogan, Y. (2026). Serum expression levels of miRNA-29b and miRNA-99b in young adults with acute ischemic stroke: a prospective observational case–control study. BMC Neurology. https://doi.org/10.1186/s12883-026-05577-y

Image Credits: AI Generated

DOI: 10.1186/s12883-026-05577-y

Keywords: acute ischemic stroke, miRNA-29b, miRNA-99b, biomarkers, young adults, NIHSS, case-control study, emergency department, BMC Neurology, microRNA, Serum, expression