Susceptibility of mature human myocardial cell types to sars-cov-2

ABSTRACT

Background: SARS-CoV-2 is a highly transmissible and virulent respiratory pathogen responsible for the global coronavirus disease 2019 (COVID-19) pandemic. A significant number of patients infected with SARS-CoV-2 show signs of myocardial injury ranging from asymptomatic troponemia to acute congestive heart failure and cardiogenic shock. The precise mechanisms underlying myocardial injury in this cohort are unclear, and it is difficult to distinguish weather new onset cardiac dysfunction is representative of active myocardial infection or a consequence of systemic illness. To address this gap in knowledge we constructed a model to assess replicative potential of SARS-CoV2 in primary cell lines derived from adult and pediatric myocardium including cardiomyocytes, fibroblasts, and endothelial cells and corroborated our in vitro findings with a pathologic analysis of myocardial tissue obtained from patients infected with SARS-CoV-2. Methods: Samples of atrial myocardium obtained from patients undergoing cardiac surgery were enzymatically digested and purified into cardiomyocyte, fibroblast, and endothelial cell populations. Susceptibility to infection with SARS-CoV-2 was then assessed in primary human myocardial cell types and compared against induced cardiomyocytes derived from human pluripotential stem cells. Infectivity was quantitatively assessed using qPCR against genomic and subgenomic viral RNA and normalized to GAPDH. Postmortem heart and lung FFPE tissue from de-identified patients who died from SARS CoV-2 infection were obtained and analyze by immunofluorescence for viral spike and nucleocapsid protein or stained with hematoxylin and eosin for histological evaluation. Results: Primary cardiomyocytes obtained from adult (n=7) and pediatric (n=7) atrial myocardium could not support active replication SARS-CoV-2 virus and there was no evidence of viral replication in pathologic myocardial specimens obtained from COVID infected patients (n=7). Collectively our data indicate that primary cardiac cell types are unable to support the level of viral replication observed in iPSCM (p=0.0007) suggesting that induced pluripotential stem cells may not adequately model the response of mature myocardium to SARS-CoV-2.