MicroRNA profiles as quality biomarkers in stored blood components: A narrative review

Blood component storage remains fundamental to modern transfusion medicine, yet storage‐associated lesions compromise the quality and safety of red blood cell (RBC) concentrates, platelet concentrates (PCs) and plasma products. Conventional quality indicators—including pH, haemolysis percentage, lactate levels, and 2,3‐diphosphoglycerate (2,3‐DPG) concentrations—provide only a partial assessment of the complex biochemical and molecular deterioration occurring during storage. MicroRNAs (miRNAs), small non‐coding RNA molecules of 18–25 nucleotides, have emerged as promising molecular biomarkers capable of reflecting the physiological state of stored blood components with high sensitivity and specificity. We examine miRNA dysregulation patterns in stored RBCs—highlighting miR‐96, miR‐150, miR‐451a and let‐7b as key indicators—and in stored PCs, where miR‐127, miR‐320a, miR‐326 and miR‐223 demonstrate significant storage‐dependent expression changes. The role of extracellular vesicle–associated miRNAs in mediating transfusion‐related immunomodulation (TRIM) is discussed, alongside the impact of pathogen inactivation technologies on miRNA integrity. Pre‐analytical challenges, technological platforms for miRNA detection and the integration of miRNA profiling with multi‐omics approaches for comprehensive quality assessment are critically appraised. Despite considerable promise, standardization of protocols, validation in large‐scale clinical settings and cost‐effectiveness analyses remain necessary before miRNA‐based quality assessment can be translated into routine blood bank practice.