EXTRACELLULAR VESICLE PROFILING IN SEVERE COVID-19 RELATED ARDS: THE IMPACT OF CHRONIC LIVER DISEASE

Chronic liver disease (CLD) increases the risk of acute respiratory distress syndrome (ARDS). Extracellular vesicles (EVs) and their microRNA (EV-miRNA) cargo mediate liver–lung interaction, but their role in ARDS remains unclear. 1) To characterize EV-miRNA profiles in critically ill patients with COVID-19 pneumonia with and without CLD, and 2) to identify molecular pathways through which CLD influences lung injury. In a case-control study, serum was collected on ICU day 1 from patients with SARS-CoV-2 pneumonia, with CLD and non-CLD groups matched for sex, age, pneumonia severity, respiratory support, and ICU length of stay. EVs were isolated with the Norgen system, size exclusion chromatography (Izon), or both, and characterized by NTA, flow cytometry, and western blot. EV-miRNAs were extracted, and 21 lung and liver-related candidates were quantified by RT-qPCR. Differential expression was assessed with REST/NormFinder, and dysregulated miRNAs were explored by Reactome, miRNet 2.0, and PANTHER for pathway and network enrichment. Thirty-one patients were included (14 with CLD). Norgen was the most effective EV isolation method. Five EV-miRNAs were significantly dysregulated in patients with CLD (adjusted P <0.05): miR-26a-5p, miR-142-5p, and miR-223-3p (downregulated) and miR-197-3p, miR-144-5p (upregulated). Network analysis identified FOXO3, PTEN, and SOD2 as key target genes. Enrichment revealed pathways in host–virus interactions, immune signaling, inflammation, growth factor/neurotrophic signaling, and cell migration, intersecting with RHO GTPase, VEGF, and TGF-β signaling relevant to pulmonary homeostasis. In critically ill COVID-19 patients, CLD is associated with differential EV-miRNA expression that influences immune, viral, and lung injury pathways, suggesting that CLD may worsen ARDS via EV-mediated signaling. This study also highlights the most effective EV isolation method for future biomarker use.