Abstract 13046: ALDH2-Mediated 4-HNE Contributes the Pathogenesis of Pulmonary Arterial Hypertension in Atherosclerotic Mice

Abstract

Introduction: A high residual mortality for patients with pulmonary arterial hypertension (PAH) in this PAH-targeted therapy era implies the existence of untargeted pathways. High fat diet-fed ApoE knockout mice were found to develop PAH phenotype. Monocrotaline (MCT)-induced PAH rats also express high levels of 4-hydroxynenonal (4-HNE), a lipid peroxidation related aldehyde, in pulmonary vessels. Aldehyde dehydrogenase-2 (ALDH2), an important enzyme responsible for the removal of 4-HNE, is functionally defective near 50% of East Asians. Whether 4-HNE and its cognate detox enzyme ALDH2 participate in lipid dysregulation-induced PAH remains poorly understood. Methods and Results: Compared with ApoE knockout mice fed with normal chow, those with Piagen diet developed hypercholesterolemia, higher right ventricular systolic pressure (RVSP), and higher Fulton index (RV hypertrophy). Atherosclerotic plaques were widely distributed in the entire major arteries as well as pulmonary arteries. The lung tissue of Paigen diet-fed mice had higher levels of ALDH2 protein but lower levels of ALDH2 enzymatic activity, which was negatively associated with serum 4-HNE levels. Importantly, lung ALDH2 activities were negatively (R= -0.829, P=0.041), and serum 4-HNE levels positively (R=0.936, P=0.006) associated with RVSP. This data suggests that, in our model, ALDH2 expression may be upregulated to counteract but still exhausted by the high levels of lipid peroxidation products, such as 4-HNE. Conclusions: This data suggests that lipid dysregulation related 4-HNE/ALDH2 imbalance, at least in part, participates in PAH development and may potentially serve as a novel PAH target, particularly for East Asian people.