Delayed viral clearance and exacerbated airway hyperinflammation in hypertensive COVID-19 patients (preprint)

In COVID-19, hypertension and cardiovascular diseases have emerged as major risk factors for critical disease progression. Concurrently, the impact of the main anti-hypertensive therapies, angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB), on COVID-19 severity is controversially discussed. By combining clinical data, single-cell sequencing data of airway samples and in vitro experiments, we assessed the cellular and pathophysiological changes in COVID-19 driven by cardiovascular disease and its treatment options. Anti-hypertensive ACEi or ARB therapy, was not associated with an altered expression of SARS-CoV-2 entry receptor ACE2 in nasopharyngeal epithelial cells and thus presumably does not change susceptibility for SARS-CoV-2 infection. However, we observed a more critical progress in COVID-19 patients with hypertension associated with a distinct inflammatory predisposition of immune cells. While ACEi treatment was associated with dampened COVID-19-related hyperinflammation and intrinsic anti-viral responses, under ARB treatment enhanced epithelial-immune cell interactions were observed. Macrophages and neutrophils of COVID-19 patients with hypertension and cardiovascular comorbidities, in particular under ARB treatment, exhibited higher expression of CCL3, CCL4, and its receptor CCR1, which associated with critical COVID-19 progression. Overall, these results provide a potential explanation for the adverse COVID-19 course in patients with cardiovascular disease, i.e. an augmented immune response in critical cells for the disease course, and might suggest a beneficial effect of clinical ACEi treatment in hypertensive COVID-19 patients.

Cross-talk between the airway epithelium and activated immune cells defines severity in COVID-19 (preprint)

The clinical course of COVID-19 is highly variable, however, underlying host factors and determinants of severe disease are still unknown. Based on single-cell transcriptomes of nasopharyngeal and bronchial samples from clinically well-characterized patients presenting with moderate and critical severities, we reveal the different types and states of airway epithelial cells that are vulnerable for SARS-CoV-2 infection. In COVID-19 patients, we observed a two- to threefold increase of cells expressing the SARS-CoV-2 entry receptor ACE2 within the airway epithelial cell compartment. ACE2 is upregulated in epithelial cells through Interferon signals by immune cells suggesting that the viral defense system may increase the number of potentially susceptible cells in the respiratory epithelium. Infected epithelial cells recruit and activate immune cells by chemokine signaling. Recruited T lymphocytes and inflammatory macrophages were hyperactivated and showed a strong interaction with epithelial cells. In critical patients, increased expression of CCL2, CCL3, CCL5, CXCL9, CXCL10, IL8, IL1B and TNF in macrophages was identified as a likely cause of a hyperinflammatory lung pathology. Moreover, we observed exacerbated epithelial cell death, likely leading to lung injury and respiratory failure in fatal cases. Our study provides novel insights into the pathophysiology of COVID-19 and suggests an immunomodulatory therapy along the CCL2, CCL3/CCR1 axis as promising option to prevent and treat critical course of COVID-19.