Transcriptome of blood cells as a reservoir of cardiovascular biomarkers

Biomarkers have the potential to move personalized medicine a step forward for the patients' benefit. Blood is a non-invasive source of biomarkers. The cell-free compartment of the blood has traditionally been used to search for biomarkers and currently used cardiovascular biomarkers are mainly measured in plasma or serum fractions. While most of these biomarkers are proteins, very few belong to the RNA family due to methodological constraints inherent to the assessment of RNAs. Over the past decade, technological developments have overcome these constraints and have allowed the assessment of RNAs in blood cells. Thus, the search for novel cardiovascular biomarkers among RNAs expressed in blood cells has emerged. This review highlights the potential of the transcriptome of blood cells to be used as a reservoir of novel cardiovascular biomarkers. First, the benefit of using biomarkers for personalized medicine is introduced. The focus is on the RNA family of biomarkers, both coding and non-coding. The value of systems-based approaches for biomarker discovery is discussed. Then, the current knowledge of the use of blood cells' transcriptome for biomarker discovery is reviewed. Recent technological developments that have facilitated the study of the transcriptome of blood cells are presented. Further axes of developments are proposed to bring RNA-based biomarkers to clinical application. Lastly, some directions for future work are presented.