A study in humans demonstrated that the miRNA expression profile of gastric content from breast-fed infants was closer to breast milk than to formula-fed infants or adult gastric juice, with the miR-186-5p being significantly more abundant in breast milk and the gastric content of breast-fed infants compared to formula-fed infants and adult gastric juice [Kakimoto et al. DOI:10.1007/S00414-019-02226-7]. A study in rhesus macaques demonstrated that the relative abundance of the miR-186-5p in plasma at day 2 post-total-body irradiation correlated with the time to severe neutropenia, identifying it as part of an eleven-miRNA panel for predicting this hematopoietic acute radiation syndrome outcome [Rogers et al. DOI:10.1667/RADE-21-00043.1]. In human newborns, next-generation sequencing identified the miR-186-5p as being downregulated in the plasma of infants with perinatal asphyxia at 0–6 hours of age compared to healthy controls [Lai et al. DOI:10.1016/j.pedneo.2024.05.002].