Guo X, et al. - Researchers determined if nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit 4 [(NOX4)] plays a role in pulmonary arteriolar remodeling of pulmonary hypertension (PH) in chronic obstructive pulmonary disease (COPD). For this purpose, they used cardiac magnetic resonance imaging (cMRI) to determine the morphological alteration of pulmonary arteries and pulmonary blood flow. They also looked at the expression and correlation of NOX4 with pulmonary vascular remodeling and pulmonary functions in COPD lungs. Based on the findings, they suggested a possible key role of the NOX4-derived reactive oxygen species production in the development of PH in COPD by promoting distal pulmonary vascular remodeling.