ABSTRACT
Pneumonia is an acute respiratory disease of varying aetiology, which drew much attention during the COVID-19 pandemic. Among many thoroughly studied aspects of pneumonia, lipid metabolism has been addressed insufficiently. Here, we report on abnormal lipid metabolism of both COVID-19- and non-COVID-19-associated pneumonias in human lungs. Morphometric analysis revealed extracellular and intracellular lipid depositions, most notably within vessels adjacent to inflamed regions, where they apparently interfere with the blood flow. Lipids were visualized on Sudan III- and Oil Red O-stained cryosections and on OsO4-contrasted semi-thin and ultrathin sections. Chromato-mass spectrometry revealed that unsaturated fatty acid content was elevated at inflammation sites compared with the intact sites of the same lung. The genes involved in lipid metabolism were downregulated in pneumonia, as shown by qPCR and in silico RNAseq analysis. Thus, pneumonias are associated with marked lipid abnormalities, and therefore lipid metabolism can be considered a target for new therapeutic strategies.
Subject(s)
Respiratory Tract Diseases , Pneumonia , Addison Disease , COVID-19 , InflammationABSTRACT
SARS-CoV-2 can infiltrate the lower respiratory tract, resulting in severe respiratory failure and a high death rate. Normally, the airway and alveolar epithelium can be rapidly reconstituted by multipotent stem cells after episodes of infection. Here, we analyzed published RNA-seq datasets and demonstrated that cells of four different lung epithelial stem cell types express SARS-CoV-2 entry factors, including Ace2. Thus, stem cells can be infected by SARS-CoV-2, which can lead to defects in regeneration capacity and account for the severity of SARS-CoV-2 infection and its consequences.