Introduction: Globally, over 65 million individuals are estimated to suffer from post-acute sequelae of COVID-19 (PASC)1. Many individuals living with PASC experience cardiovascular symptoms (i.e. chest pain and heart palpitations) (PASC-CVS)2. The role of chronic inflammation in these symptoms, in particular in individuals with symptoms persisting for >1 year after SARS-CoV-2 infection, remains to be determined.
Methods: Plasma samples were donated from healthy and fully recovered patients, and individuals with long-term PASC-CVS (defined by self-reported symptoms of chest pain and/or heart palpitations persisting for >1 year after SARS-CoV-2 infection). Samples were investigated for differences in transcriptome and proteome, and inflammatory cytokine and cardiac damage biomarker levels. Both samples and recombinant human cytokines were used to treat human cardiomyocytes to assess direct effects on cardiac physiology.
Results: Here, we show that compared to individuals with a resolved SARS-CoV-2 infection (and no persistent symptoms), individuals with prolonged PASC-CVS had elevated levels of pro-inflammatory cytokines. However, these cytokines were found to be present in trace amounts, such that they could only be detected with the use of novel nanotechnology3. Importantly, these trace-level cytokines had a direct effect on the functionality of primary human cardiomyocytes in vitro. Proteomics analyses demonstrated further differences in PASC-CVS and recovered plasma including increased abundance of complement and coagulation associated proteins.
Conclusion: Together, these data provide important new insights into the cardiovascular complications of the complex disease that is PASC and offers opportunities to improve the diagnosis, treatment and understanding of the ever-growing number of individuals living with PASC-CVS.