The nitrofen/bisdiamine murine model of congenital diaphragmatic hernia has a pulmonary hypertension vascular phenotype consistent with human CDH

Congenital diaphragmatic hernia (CDH)-associated pulmonary hypertension (CDH-PH) has severe implications for the survival of patients with CDH; however, CDH-PH is often refractory to pulmonary vasodilators, rendering it difficult to treat. As such, models are necessary to study the etiology, mechanism, onset, and progression of pulmonary vascular remodeling in CDH. Despite several established murine models of CDH, no characterized CDH-PH or CDH-associated pulmonary vascular remodeling murine model exists. In this work, we assessed the nitrofen/bisdiamine (N/B) murine CDH model for pulmonary hypertension (PH) hallmarks to establish its usefulness as a model for studying mechanisms leading to CDH-PH. To do so, we evaluated key metrics of vascular PH at two different gestational time points and compared the results to sex- and age-matched human CDH tissue sections and results from a meta-analysis of published data of human CDH samples. We found that vessel rarefaction, smooth muscle hypertrophy, and adventitial extracellular matrix deposition were present in the N/B CDH murine model at <i>E18.5</i> in late gestation. In addition, this same vascular PH phenotype was present much earlier in development at <i>E16.5</i>, after normal diaphragmatic development and closure, but still within the pseudoglandular phase of lung development. Finally, comparisons with human CDH data confirm that the N/B CDH murine model recapitulates the pulmonary hypertension vascular phenotype seen in human CDH lung sections. Together, these data validate a mouse CDH-PH model with the ability to genetically perturb pathways that may exacerbate or improve CDH-PH outcomes, which could, in turn, lead to therapies or diagnostic markers of CDH-PH severity in utero.<b>NEW & NOTEWORTHY</b> Pulmonary hypertension (PH) is a severe complication of congenital diaphragmatic hernia (CDH), yet mechanisms and potential interventions remain poorly understood, partly due to the lack of animal models. This study validated that the nitrofen/bisdiamine (N/B) CDH mouse model recapitulates a PH vascular phenotype, including vessel rarefaction, smooth muscle hypertrophy, and remodeling that is benchmarked to human CDH tissues. These findings suggest that this model is a robust in vivo tool for the mechanistic study of CDH-PH.