Abstract 12949: Altered Fatty Acids and Oxylipins Metabolism Differentiate Isolated Post-Capillary versus Combined Pre- and Post-Capillary Pulmonary Hypertension

Abstract

Introduction: Pulmonary hypertension due to left heart disease (Group 2) is the most common type of pulmonary hypertension and has two subtypes: isolated post-capillary pulmonary hypertension (Ipc-PH) and combined post-capillary and pre-capillary pulmonary hypertension (Cpc-PH). Little is known about the molecular characteristics that distinguish these two subphenotypes or if Cpc-PH shares molecular similarities to pulmonary arterial hypertension (PAH), as has previously been suggested. Many lipid metabolites, including a diverse group of bioactive lipid mediators known as oxylipins, have been associated with cardiovascular disease and other inflammatory conditions. Therefore, we sought to characterize oxylipin and other bioactive lipid profiles among patients with Ipc-PH and Cpc-PH, as well as those with PAH. Methods: We studied 129 patients with Ipc-PH (n=38), Cpc-PH (n=52), or PAH (n=39) between June 2006 and March 2012. Liquid chromatography-mass spectrometry was used to assess 350 lipid metabolite analytes in each patient. Results: In multivariable analyses adjusting for age, sex, BMI, and pulmonary hypertension medications, we observed 34 metabolites were significantly increased and 10 were decreased in Ipc-PH compared to Cpc-PH (Figure). Among these same metabolites, only 9 were significantly different between Cpc-PH and PAH. Compared to patients with Ipc-PH, those with Cpc-PH had elevated levels of fatty acyl esters of hydroxy fatty acids and polyunsaturated fatty acids as well as lower levels of anti-inflammatory and pulmonary vascular relaxant oxylipins. Conclusions: Overall, these findings suggest that Cpc-PH may diverge from Ipc-PH and share some molecular similarities with PAH. Identifying key molecular targets involved in Cpc-PH pathophysiology may be critical for diagnostic purposes and in the development of novel therapeutic avenues for patients with Cpc-PH.