Pulmonary arterial hypertension induces a metabolic and inflammatory hepatopathy.

BACKGROUNDRight ventricular failure (RVF) is a major determinant of mortality in pulmonary arterial hypertension (PAH), and hepatic dysfunction predicts adverse outcomes. However, the cell-specific effects of PAH/RVF on the human liver remain poorly defined.METHODSWe performed single-nucleus RNA-seq (snRNA-seq) of autopsy-derived liver tissue from 5 patients with PAH and 4 healthy individuals (non-PAH) treated as controls and compared these findings with publicly available snRNA-seq datasets from nonalcoholic steatohepatitis (NASH) and Fontan-associated liver disease (FALD). Transcriptomic analyses were integrated with histologic assessment, mitochondrion-enriched proteomics, and correlations with clinical markers of PAH/RVF severity.RESULTSPAH livers showed cell-specific metabolic, inflammatory, and fibrotic remodeling distinct from NASH and FALD. PAH hepatocytes exhibited a hypoxia-adapted, Warburg-like metabolic phenotype with reduced fatty acid metabolism, gluconeogenesis, cytochrome P450 activity, and ketone metabolism. PAH endothelial cells demonstrated increased glycolytic pathway activity and altered adhesion/barrier signaling. PAH hepatic stellate cells (HSCs) displayed HIF-1 and PI3K/Akt pathway activation, increased IL-6 expression, and histologic evidence of perivascular fibrotic remodeling. PAH macrophages showed complement activation with reduced JAK/STAT signaling. HSC HIF-1 activity correlated with clinical markers of PAH/RVF severity.CONCLUSIONPAH induces a distinct metabolic and inflammatory hepatopathy characterized by hepatocyte metabolic reprogramming, HSC activation, macrophage complement signaling, and suppressed ketone metabolism. These findings support PAH-associated hepatopathy as a disease-specific end-organ phenotype linked to RVF severity.FUNDINGNIH grants F31 HL170585, R01 HL158795, and R01 HL162927.