Can microRNAs emerge as biomarkers in distinguishing HFpEF versus HFrEF?

MicroRNAs (miRNAs) are short strands of approximately 21-25 nucleotides. MiRNAs are emerging as important biomarker candidates for various cardiovascular diseases. These small molecules are being currently investigated for diagnosis, prognosis and more importantly as therapeutic targets. This review tries to explore the possibility of identifying miRNAs that are specific to Heart Failure with reduced Ejection Fraction (HFrEF) and Heart Failure with preserved Ejection Fraction (HFpEF) as both conditions carry equal morbidity and mortality risks, but drastically differ in their underlying pathophysiology. The concept of circulating miRNAs as biomarkers needs further investigation because the mechanism of their release into circulation still remains elusive; and, the biological correlation between circulatory miRNA and the relevant organ/tissue expression has not been established. A growing body of evidence indicates that miRNA may "shuttle" in between intracellular compartments for paracrine activities. Generating different panels of miRNAs may be useful in distinguishing HFrEF vs HFpEF. The use of antisense oligonucleotides to silence miRNAs would be another avenue towards establishing target-driven therapeutics in the context of personalized medicine.