Urinary exosomal miR-132-3p as a novel non‑invasive biomarker for kidney scarring in pediatric vesicoureteral reflux patients

To assess the potential of urinary exosomal miRNA as a predictor of kidney scarring in children with vesicoureteral reflux (VUR). A prospective study was conducted in pediatrics diagnosed with VUR between September 2023 to December 2025. Urinary exosomes were isolated from patients via ultracentrifugation and subsequently characterized using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and Western blot. The expression levels of exosomal miRNAs were profiled using miRNA sequencing and validated by quantitative real-time PCR. Kidney scarring was determined based on dimercaptosuccinic acid (DMSA) scintigraphy, and its association with the identified urinary exosomal miRNAs was investigated. This prospective study enrolled 81 patients, comprising 33 males and 48 females, with a median age of 27 months (IQR: 8–82). Urinary exosomal miR-132-3p expression was significantly associated with higher reflux grade, bilateral reflux, and the presence of kidney scarring. Multivariate logistic analysis showed that urinary exosomal miR-132-3p (OR = 4.937, 95% CI: 1.906–12.781, P < 0.001) was a significant predictor of kidney scarring with a high predictive value with an area under the curve (AUC) of 0.908 (95% CI: 0.823–0.961, P < 0.001). In this exploratory single-centre cohort, urinary exosomal miR-132-3p serves as a promising non-invasive biomarker for the prediction of kidney scarring in children with VUR.