Defining a pathological role for the vasculature in the development of fibrosis and pulmonary hypertension in interstitial lung disease

Examining the Development of Chronic Thromboembolic Pulmonary Hypertension at the Single-Cell Level

BACKGROUND

The mechanism of chronic thromboembolic pulmonary hypertension (CTEPH) is known to be multifactorial but remains incompletely understood.

METHODS

In this study, single-cell RNA sequencing, which facilitates the identification of molecular profiles of samples on an individual cell level, was applied to investigate individual cell types in pulmonary endarterectomized tissues from 5 patients with CTEPH. The order of single-cell types was then traced along the developmental trajectory of CTEPH by trajectory inference analysis, and intercellular communication was characterized by analysis of ligand-receptor pairs between cell types. Finally, comprehensive bioinformatics tools were used to analyze possible functions of branch-specific cell types and the underlying mechanisms.

RESULTS

Eleven cell types were identified, with immune-related cell types (T cells, natural killer cells, macrophages, and mast cells) distributed in the left (early) branch of the pseudotime tree, cancer stem cells, and CRISPLD2+ cells as intermediate cell types, and classic disease-related cell types (fibroblasts, smooth muscle cells, myofibroblasts, and endothelial cells) in the right (later) branch. Ligand-receptor interactions revealed close communication between macrophages and disease-related cell types as well as between smooth muscle cells and fibroblasts or endothelial cells. Moreover, the ligands and receptors were significantly enriched in key pathways such as the PI3K/Akt signaling pathway. Furthermore, highly expressed genes specific to the undefined cell type were significantly enriched in important functions associated with regulation of endoplasmic reticulum stress.

CONCLUSIONS

This single-cell RNA sequencing analysis revealed the order of single cells along a developmental trajectory in CTEPH as well as close communication between different cell types in CTEPH pathogenesis.

COVID-19 pneumonia and the pulmonary vasculature - a marriage made in hell

Automated analysis of medical images is not new [1–3]. Researchers in the respiratory sciences and, particularly, the field of interstitial lung diseases, have long enthused about the potential for computers to analyse medical images thereby revealing “signals” hitherto invisible to the human eye: an enthusiasm only enhanced by recent developments in machine learning and artificial intelligence [4–6]. By leveraging the central importance of computed tomography (CT) scanning for diagnosis, treatment decisions and prognostication, a key aim is to identify imaging biomarkers to more accurately phenotype disease and, in so doing, move a step closer to truly patient-centric medicine. Another goal is to apply novel imaging analyses to pathogenesis, disease “behaviour” and prognostication in the hope that this might unlock new therapeutic approaches. Given the digital nature of the data and the potentially myriad imaging patterns, frequently compounded by patient, therapeutic and disease-based factors, lung imaging is ideally suited to more sophisticated analytic approaches.

Quantitative CT of the pulmonary vasculature is potentially important in COVID-19 associated pneumoniahttps://bit.ly/3vUTTRM

Cardiorenal Tissues Express SARS-CoV-2 Entry Genes and Basigin (BSG/CD147) Increases With Age in Endothelial Cells

Vascular and cardiovascular inflammation and thrombosis occur in patients with severe coronavirus disease-2019 (COVID-19). Advancing age is the most significant risk factor for severe COVID-19. Using transcriptomic databases, the authors found that: 1) cardiovascular tissues and endothelial cells express putative genes for severe acute respiratory syndrome coronavirus-2 infection, including angiotensin-converting enzyme 2 (ACE2) and basigin (BSG); 2) severe acute respiratory syndrome coronavirus-2 receptor pathways ACE2/transmembrane serine protease 2 and BSG/peptidylprolyl isomerase B(A) polarize to lung/epithelium and vessel/endothelium, respectively; 3) expression of host genes is relatively stable with age; and 4) notable exceptions are ACE2, which decreases with age in some tissues, and BSG, which increases with age in endothelial cells, suggesting that BSG expression in the vasculature may explain the heightened risk for severe disease with age.