Good laboratory and experimental practices for microRNA analysis in cardiovascular research

Cardiovascular diseases (CVDs) are a major cause of death worldwide, especially in developed countries. Noncoding RNA molecules and particularly circulating microRNAs (miRNAs) have become potential diagnostic, prognostic, and therapeutic biomarkers for CVDs. In the cardiovascular system, miRNAs regulate numerous biological functions while they have been implicated in the pathogenesis of several CVDs. miRNAs exhibit several advantages over other biological molecules (proteins, cytokines, and peptides), especially due to their high stability in circulation and under extreme pH and temperature conditions. However, it is still challenging to accurately determine miRNA levels and several preanalytical and analytical issues need to be addressed. Methodological heterogeneity in sample storage and handling, extraction and quantification of miRNAs, and data normalization resulted in inconsistency among different studies. In this chapter, we highlight the factors that must be taken into account when studying circulating miRNAs and we propose laboratory and experimental practices to ensure valid scientific inference.