Circulating miR-452 and miR-22-3p as biomarkers for sepsis-associated acute kidney injury: a cross-sectional study

Sepsis is a major cause of acute kidney injury (AKI), responsible for nearly half of all AKI cases and associated with high mortality. Early identification of AKI in septic patients is critical to guide timely intervention. Circulating microRNAs (miRNAs), particularly miR-22-3p and miR-452, have emerged as promising non-invasive biomarkers due to their stability and role in regulating inflammation and apoptosis. To evaluate serum miR-452 and miR-22-3p as biomarkers associated with the presence and severity of SA-AKI at ICU admission. In this cross sectional observational study,80 adult septic patients admitted to Zagazig University Hospitals were enrolled and divided into two matched groups: 40 with sepsis-associated AKI and 40 with sepsis only without AKI. Serum miR-452 and miR-22-3p were quantified at ICU admission using qRT-PCR and analyzed in relation to AKI presence, KDIGO stage, and clinical/laboratory markers. Serum miR-452 levels were noticeably higher in the AKI group (p < 0.001) and demonstrated strong diagnostic accuracy (AUC = 0.846; cutoff ≥ 0.905; sensitivity and specificity = 80%). For KDIGO Stage 3, miR-452 showed an AUC of 0.869 (cutoff ≥ 2.503; sensitivity = 83.3%, specificity = 89.3%). miR-452 levels strongly correlated with serum creatinine (r = 0.648), BUN, WBCs, ESR, and lactate (all p < 0.05). In contrast, miR-22-3p levels revealed no significant differenc between AKI and non-AKI groups (p = 0.485) but adversely correlated with creatinine (r = –0.262, p = 0.019) and the lowest values were in patients with advanced KDIGO stages (p < 0.001). Serum miR-452 is strongly associated with SA-AKI presence and severity at ICU admission and may support risk stratification in septic patients. miR-22-3p is not a discriminator for AKI presence but may reflect severity. Longitudinal studies with serial sampling and outcome assessment are needed to confirm temporal patterns and prognostic utility.