Cardiac megakaryocytes in SARS-CoV-2-positive autopsies
Kara L Gawelek1, Robert Padera1, Jean Connors2
1Department of Pathology, Brigham and Women's Hospital Harvard Medical School, Boston, Massachusetts, USA.
Insights
Cardiac megakaryocytes were found in a majority of COVID-19 autopsies, but their presence may indicate a general inflammatory response, not specific to SARS-CoV-2 infection.
Area of Science:
- Pathology
- Hematology
- Infectious Diseases
Background:
- Thromboembolic phenomena are a significant complication of severe acute respiratory coronavirus 2 (SARS-CoV-2) infection.
- The role of platelets and megakaryocytes in Coronavirus Disease 2019 (COVID-19) is under investigation.
- Previous studies noted megakaryocytes in cardiac microvasculature of deceased COVID-19 patients.
Purpose of the Study:
- To evaluate the presence and frequency of cardiac megakaryocytes in autopsies of COVID-19 patients.
- To correlate cardiac megakaryocytes with pulmonary emboli, platelet parameters, and inflammatory markers.
- To determine if cardiac megakaryocytes are specific to COVID-19 or indicative of a broader inflammatory response.
Main Methods:
- Autopsy analysis of 36 SARS-CoV-2 positive patients and 12 prepandemic controls.
- Assessment for cardiac megakaryocytes.
- Correlation with pulmonary emboli, platelet counts, and inflammatory markers.
Main Results:
- Cardiac megakaryocytes were detected in 64% of COVID-19 autopsies and 40% of prepandemic autopsies.
- COVID-19 cases with cardiac megakaryocytes showed significantly higher platelet counts.
- No other platelet parameters or inflammatory markers showed significant differences between groups.
Conclusions:
- Cardiac megakaryocytes are frequent in COVID-19 autopsies but also present in controls.
- Their presence may represent a nonspecific inflammatory response rather than being exclusive to SARS-CoV-2 infection.
- Further research is needed to fully elucidate the role of megakaryocytes in COVID-19 pathogenesis.
Abstract:
Thromboembolic phenomena are an important complication of infection by severe acute respiratory coronavirus 2 (SARS-CoV-2). Increasing focus on the management of the thrombotic complications of Coronavirus Disease 2019 (COVID-19) has led to further investigation into the role of platelets, and their precursor cell, the megakaryocyte, during the disease course. Previously published postmortem evaluations of patients who succumbed to COVID-19 have reported the presence of megakaryocytes in the cardiac microvasculature. Our series evaluated a cohort of autopsies performed on SARS-CoV-2-positive patients in 2020 (n = 36) and prepandemic autopsies performed in early 2020 (n = 12) and selected to represent comorbidities common in cases of severe COVID-19, in addition to infectious and noninfectious pulmonary disease and thromboembolic phenomena. Cases were assessed for the presence of cardiac megakaryocytes and correlated with the presence of pulmonary emboli and laboratory platelet parameters and inflammatory markers. Cardiac megakaryocytes were detected in 64% (23/36) of COVID-19 autopsies, and 40% (5/12) prepandemic autopsies, with averages of 1.77 and 0.84 megakaryocytes per cm2 , respectively. Within the COVID-19 cohort, autopsies with detected megakaryocytes had significantly higher platelet counts compared with cases throughout; other platelet parameters were not statistically significant between groups. Although studies have supported a role of platelets and megakaryocytes in the response to viral infections, including SARS-CoV-2, our findings suggest cardiac megakaryocytes may be representative of a nonspecific inflammatory response and are frequent in, but not exclusive to, COVID-19 autopsies.
