Interferon‐alpha or ‐beta Facilitates SARS‐CoV‐2 Pulmonary Vascular Infection by Inducing ACE2

Severe viral pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is characterized by a hyperinflammatory state typified by elevated circulating pro‐inflammatory cytokines, frequently leading to potentially lethal vascular complications including thromboembolism, disseminated intracellular coagulopathy and vasculitis. Though endothelial infection and subsequent endothelial damage have been described in patients with fatal COVID‐19, the mechanism by which this occurs remains elusive, particularly given that, under naïve conditions, pulmonary endothelial cells demonstrate minimal cell surface expression of the SARS‐CoV‐2 binding receptor ACE2. Herein we describe SARS‐CoV‐2 infection of the pulmonary endothelium in postmortem lung samples from individuals who died of COVID‐19, demonstrating both heterogeneous ACE2 expression and endothelial damage (Figure). In primary endothelial cell cultures, we show that SARS‐CoV‐2 infection is dependent on the induction of ACE2 protein expression and that this process is facilitated by type 1 interferon‐alpha (IFNα) or ‐beta(β) ‐ two of the main anti‐viral cytokines induced in severe SARS‐CoV‐2 infection ‐ but not significantly by other cytokines (including interleukin 6 and interferon g /λ). Our findings suggest that the stereotypical anti‐viral interferon response may paradoxically facilitate the propagation of COVID‐19 from the respiratory epithelium to the vasculature, raising concerns regarding the use of exogenous IFNα/β in the treatment of patients with COVID‐19.

Acute Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Pregnancy Is Associated with Placental Angiotensin-Converting Enzyme 2 Shedding.

While the human placenta may be infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the rate of fetal transmission is low, suggesting a barrier at the maternal-fetal interface. Angiotensin-converting enzyme (ACE)2, the main receptor for SARS-CoV-2, is regulated by a metalloprotease cleavage enzyme, a disintegrin and metalloprotease domain 17 (ADAM17). ACE2 is expressed in the human placenta, but its regulation in relation to maternal SARS-CoV-2 infection in pregnancy is not well understood. This study evaluated ACE2 expression, ADAM17 activity, and serum ACE2 abundance in a cohort of matched villous placental and maternal serum samples from control pregnancies (SARS-CoV-2 negative, n = 8) and pregnancies affected by symptomatic maternal SARS-CoV-2 infections in the second trimester [2nd Tri coronavirus disease (COVID), n = 8] and third trimester (3rd Tri COVID, n = 8). In 3rd Tri COVID compared with control and 2nd Tri COVID villous placental tissues, ACE2 mRNA expression was remarkably elevated; however, ACE2 protein expression was significantly decreased with a parallel increase in ADAM17 activity. Soluble ACE2 was also significantly increased in the maternal serum from 3rd Tri COVID infections compared with control and 2nd Tri COVID pregnancies. These data suggest that in acute maternal SARS-CoV-2 infections, decreased placental ACE2 protein may be the result of ACE2 shedding and highlights the importance of ACE2 for studies on SARS-CoV-2 responses at the maternal-fetal interface.

Asthma Management in the Era of the COVID-19 Pandemic.

Asthma is common in children and exacerbations are usually triggered by respiratory viruses. There was considerable concern about the impact of COVID-19 on children with asthma. It was expected that children with asthma would fare poorly during the pandemic. However, the reported effect of the COVID-19 pandemic on pediatric asthma including acute asthma admissions, does not appear to be significant, but this needs careful follow-up. The socioeconomic effects of the pandemic and reduced healthcare access could potentially impact on ongoing delivery of health care in chronic respiratory conditions including asthma, especially in resource-poor settings. Children with chronic asthma need to be treated as per internationally published guidelines with innovative models of disease monitoring and ongoing care during the pandemic. During the pandemic, children with acute asthma need to be managed carefully based on local guidelines and using strict infection control policies. The use of technology such as telehealth and various tools of asthma management including questionnaires and digital monitoring will play an important role in asthma management during the pandemic. Medical professionals, healthcare administrators, and governments should be sensitive to the evolving needs of the community and work closely to continue to provide services in a challenging yet unresolved pandemic.

Interferon-alpha or -beta facilitates SARS-CoV-2 pulmonary vascular infection by inducing ACE2.

Severe viral pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by a hyperinflammatory state typified by elevated circulating pro-inflammatory cytokines, frequently leading to potentially lethal vascular complications including thromboembolism, disseminated intracellular coagulopathy and vasculitis. Though endothelial infection and subsequent endothelial damage have been described in patients with fatal COVID-19, the mechanism by which this occurs remains elusive, particularly given that, under naïve conditions, pulmonary endothelial cells demonstrate minimal cell surface expression of the SARS-CoV-2 binding receptor ACE2. Herein we describe SARS-CoV-2 infection of the pulmonary endothelium in postmortem lung samples from individuals who died of COVID-19, demonstrating both heterogeneous ACE2 expression and endothelial damage. In primary endothelial cell cultures, we show that SARS-CoV-2 infection is dependent on the induction of ACE2 protein expression and that this process is facilitated by type 1 interferon-alpha (IFNα) or -beta(ß)-two of the main anti-viral cytokines induced in severe SARS-CoV-2 infection-but not significantly by other cytokines (including interleukin 6 and interferon γ/λ). Our findings suggest that the stereotypical anti-viral interferon response may paradoxically facilitate the propagation of COVID-19 from the respiratory epithelium to the vasculature, raising concerns regarding the use of exogenous IFNα/ß in the treatment of patients with COVID-19.

ATS Core Curriculum 2021. Pediatric Pulmonary Medicine: Pulmonary Infections.

The following is a concise review of the Pediatric Pulmonary Medicine Core reviewing pediatric pulmonary infections, diagnostic assays, and imaging techniques presented at the 2021 American Thoracic Society Core Curriculum. Molecular methods have revolutionized microbiology. We highlight the need to collect appropriate samples for detection of specific pathogens or for panels and understand the limitations of the assays. Considerable progress has been made in imaging modalities for detecting pediatric pulmonary infections. Specifically, lung ultrasound and lung magnetic resonance imaging are promising radiation-free diagnostic tools, with results comparable with their radiation-exposing counterparts, for the evaluation and management of pulmonary infections. Clinicians caring for children with pulmonary disease should ensure that patients at risk for nontuberculous mycobacteria disease are identified and receive appropriate nontuberculous mycobacteria screening, monitoring, and treatment. Children with coronavirus disease (COVID-19) typically present with mild symptoms, but some may develop severe disease. Treatment is mainly supportive care, and most patients make a full recovery. Anticipatory guidance and appropriate counseling from pediatricians on social distancing and diagnostic testing remain vital to curbing the pandemic. The pediatric immunocompromised patient is at risk for invasive and opportunistic pulmonary infections. Prompt recognition of predisposing risk factors, combined with knowledge of clinical characteristics of microbial pathogens, can assist in the diagnosis and treatment of specific bacterial, viral, or fungal diseases.