RT Journal Article SR Electronic T1 Metabolic profiling of pulmonary vascular phenotypes in systemic sclerosis JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1524 DO 10.1183/13993003.congress-2020.1524 VO 56 IS suppl 64 A1 Simpson, Catherine A1 Mathai, Stephen A1 Kolb, Todd A1 Hassoun, Paul A1 Aja, Susan A1 Roux, Aurelie A1 Graham, David A1 Damico, Rachel YR 2020 UL http://erj.ersjournals.com/content/56/suppl_64/1524.abstract AB The molecular determinants of PAH risk and disease severity in systemic sclerosis (SSc) are poorly understood. We hypothesized that metabolic profiling of SSc serum would enable 1) discrimination of PAH, and 2) discovery of metabolic patterns associated with distinct pulmonary vascular phenotypes.Serum from 24 adult subjects with SSc (12 with and 12 without PAH) underwent mass spectrometry for targeted metabolomics. Metabolite associations with clinical variables were examined with standard statistical and bioinformatic approaches. 3 clusters of subjects with unique metabolic patterns were formed on the basis of metabolites alone, and clinical differences were compared across clusters.Metabolites of purine catabolism (e.g. hypoxanthine, raw p 0.027) and bile acid synthesis (e.g. glycocholate, raw p 0.006) differed in SSc with versus without PAH in significance analysis of metabolites. In SSc-PAH, metabolites discriminated subjects whose NYHA functional class improved with PAH therapy. A trend for increasing disease severity was observed across metabolite clusters, with more adverse hemodynamics, shorter 6 minute walk distance, and shorter survival time in cluster 1 compared to clusters 2 and 3 (Figure). Bile acid and caffeine metabolite concentrations contributed to cluster differences.Metabolites discriminate pulmonary vascular phenotypes in SSc. Unique metabolic patterns may be novel biomarkers of PAH risk and severity in SSc. Figure:FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 1524.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).