Increased MAO-A activity promotes progression of pulmonary arterial hypertension

Xiao-Qing Sun, Eva L. Peters, Ingrid Schalij, Julie Birkmose Axelsen, Stine Andersen, Kondababu Kurakula, Maria Catalina Gomez-Puerto, Robert Szulcek, Xiaoke Pan, Denielli da Silva Goncalves Bos, Roy E. J. Schiepers, Asger Andersen, Marie-José Goumans, Anton Vonk Noordegraaf, Willem J. van der Laarse, Frances S. de Man, Harm Jan Bogaard*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Monoamine oxidases (MAOs), a class of enzymes bound to the outer mitochondrial membrane, are important sources of reactive oxygen species. Increased MAO-A activity in endothelial cells and cardiomyocytes contributes to vascular dysfunction and progression of left heart failure. We hypothesized that inhibition of MAO-A can be used to treat pulmonary arterial hypertension (PAH) and right ventricular (RV) failure. MAO-A levels in lung and RV samples from patients with PAH were compared with levels in samples from donors without PAH. Experimental PAH was induced in male Sprague-Dawley rats by using Sugen 5416 and hypoxia (SuHx), and RV failure was induced in male Wistar rats by using pulmonary trunk banding (PTB). Animals were randomized to receive either saline or the MAO-A inhibitor clorgyline at 10 mg/kg. Echocardiography and RV catheterization were performed, and heart and lung tissues were collected for further analysis. We found increased MAO-A expression in the pulmonary vasculature of patients with PAH and in experimental experimental PAH induced by SuHx. Cardiac MAO-A expression and activity was increased in SuHx- and PTB-induced RV failure. Clorgyline treatment reduced RV afterload and pulmonary vascular remodeling in SuHx rats through reduced pulmonary vascular proliferation and oxidative stress. Moreover, clorgyline improved RV stiffness and relaxation and reversed RV hypertrophy in SuHx rats. In PTB rats, clorgyline had no direct clorgyline had no direct effect on the right ventricle effect. Our study reveals the role of MAO-A in the progression of PAH. Collectively, these findings indicated that MAO-A may be involved in pulmonary vascular remodeling and consecutive RV failure.
Original languageEnglish
Pages (from-to)331-343
Number of pages13
JournalAmerican Journal of Respiratory Cell and Molecular Biology
Issue number3
Early online date2 Dec 2020
Publication statusPublished - 1 Mar 2021

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