Circulating plasma microRNAs as biomarkers for iron status in blood donors.

OBJECTIVES: To investigate whether microRNAs can serve as biomarkers for iron status in blood donors. BACKGROUND: Serum ferritin is a widely used biochemical test for detecting iron deficiency, but it has its limitations. Certain microRNAs (miRNAs) reportedly have a role in regulating iron homeostasis. Circulating miRNAs have been reported as potential biomarkers for various conditions but have not yet been studied in iron deficiency. METHODS: Participating blood donors were divided into two groups: high ferritin (HF) (>150 µg L-1 ) and low ferritin (LF) (<15 µg L-1 ). MiRNA analysis was performed by an miRNA profiling service (Exiqon) using commercial qPCR assays. The study had two phases: (i) a pilot study (20 participants) where 179 miRNAs were analysed and (ii) a confirmation study (50 participants) of 13 selected miRNAs. RESULTS: Mean serum ferritin was 13·8 µg L-1 in the LF arm compared to 231 µg L-1 in the HF group (P < 0·001). Hepcidin plasma levels were higher in the HF arm (P < 0·001), whereas soluble transferrin receptor 1 was higher in the LF group (P < 0·001). In the pilot study, samples did not separate according to study group on unsupervised analysis. When directly comparing HF vs LF groups, 17 miRNAs were differentially expressed (P < 0·05, t-test) but did not pass correction for multiple testing. The confirmation study of 13 selected miRNAs verified these findings as no miRNA was significantly different between the study groups. CONCLUSION: In this study, circulating plasma miRNAs did not emerge as promising biomarkers for iron status in healthy individuals. However, in the future, alternative detection methods such as next-generation sequencing might indicate miRNAs that correlate with iron stores.