Project 467048

Canada has reported over 1.7 million confirmed cases of coronavirus-19 disease (COVID-19), 91,000 hospitalizations, and 29,000 deaths. While over 53% of discharged patients demonstrate persistent breathlessness (dyspnea for over 12 weeks post-infection), this is also a common occurrence in non-hospitalized patients. ;Long COVID or chronic COVID is an ill-defined term used to describe when symptoms persist for months after infection. Pulmonary Vascular Disease (PVD) is an important contributor of dyspnea and shares clinical similarities to Long COVID including low diffusion capacity for carbon monoxide (DLCO) and inefficient ventilation on cardiopulmonary exercise testing (CPET). Small fragments of genomic DNA released into circulation after cell apoptosis called cell-free DNA (cfDNA) can serve as an important biomarker for detecting PVD in patients with Long COVID. Increased concentrations of plasma cfDNA indicate injury or stress. Importantly, since cfDNA conserves epigenetic information, we can use it to detect what tissues are experiencing stress. By identifying what differentially methylated regions (DMRs) correspond with PVD, we can evaluate if an increase in cfDNA with the DMR profile that correspond to PVD is present in patients with Long COVID.We will develop methylation profiles and identify DMRs for target tissues implicated in PVD. We will then validate these DMRs on their ability to detect PVD using cfDNA isolated from patients with and without PVD. Finally, we will use our validated assay to investigate whether patients with Long COVID have PVD. We will use digital droplet polymerase chain reaction (ddPCR) with DMR-specific primers to obtain the absolute amount of cfDNA from tissue damaged in PVD.