Decreased Endothelial Cell Retinoic Acid Signaling Accelerates Progression of Single Ventricle Pulmonary Vascular Malformations.

Pulmonary vascular malformations (PVMs) are vascular complications that universally develop in patients with single ventricle congenital heart disease after Glenn surgery, yet the pathogenesis of single ventricle PVMs remains unknown. Using a surgical rat model of Glenn circulation, single-cell RNA sequencing (scRNAseq) on whole lung samples identified dramatic endothelial cell (EC) gene expression changes post-surgery, including decreased all-trans retinoic acid (ATRA) signaling. Many gene expression differences (∼17% of all EC differentially expressed genes), including decreased ATRA signaling, were shared with 2 independent models of hereditary hemorrhagic telangiectasia arteriovenous malformations (AVMs). Subsequent dietary modification of vitamin A (Vit A) intake in rats, identified that dietary deficiency of Vit A increased PVM shunting severity, which was mitigated with excess dietary Vit A intake. Collectively, our study of post-Glenn PVMs identified shared patho-mechanisms with hereditary hemorrhagic telangiectasia AVMs, including decreased EC ATRA signaling, which is a novel potential target for treating AVMs.