An Engineered Human Ductus Arteriosus Capable of Biomimetic Response to Vasoactive Agents

PROJECT SUMMARY The overarching goal of this proposal is to leverage leading-edge technologies in bioengineering and vascular physiology to develop a human ductus arteriosus (DA) construct that mimics the response of native vessels to biomechanical and pharmacologic stimuli. In utero, the DA is an essential fetal artery connecting the pulmonary and systemic circulations, shunting blood away from the developing lungs. Circulatory adaptation at birth requires rapid constriction of the DA to facilitate proper perfusion of the newly inflated lungs. Failure to close postnatally results in a persistent left-to-right shunt, termed patent ductus arteriosus (PDA), which is associated with a myriad of debilitating morbidities and neonatal death. The occurrence of PDA is significant (0.05-0.2% of term infants, up to 80% of critically ill premature infants) but, to date, pharmacological therapies aimed at promoting vessel closure are quite limited in number and effectiveness. Current PDA drugs are non-specific and associated with significant off-target effects, including renal dysfunction, platelet abnormalities, spontaneous intestinal perforation, and necrotizing enterocolitis. Furthermore, they are ineffective in 30% of patients, exposing such infants to increased risk of adverse effects with no therapeutic benefit. Surgical ligation and catheter-based closure are effective alternatives, but these mechanical approaches come with their own risks and limitations. Studies have shown that some PDAs will spontaneously close over time, but it is not currently possible to accurately predict which cases will do so and which will require intervention. Advances in PDA management have been impeded by the lack of an appropriate model in which to identify PDA biomarkers and validate potential therapeutics. Animal models are poor mimics of the human DA transcriptome and morphology, and ethical concerns limit drug development efforts using human infants. Moreover, neither approach allows researchers to adjust physiological parameters in a controlled fashion to better understand DA biology. To overcome these critical limitations in predicting spontaneous PDA closure and in developing PDA therapeutics, we will utilize novel immortalized human DA smooth muscle and endothelial cell lines (SMCs and ECs) to develop a 3D engineered human DA construct capable of specifically responding to vasoactive agents in a biomimetic fashion. In Aim 1, we will use pulsatile flow to induce immortalized human DA SMCs embedded in a 3D tubular hydrogel to exhibit contractile phenotype and circumferential alignment (both of which are necessary for the initial vasoconstriction step of DA closure). Aim 2 will focus on establishing a functional DA-specific endothelium on the interior of the engineered vessel. In Aim 3, we will validate the ability of the engineered DA construct to specifically respond to known factors that regulate DA closure. This platform will have far-reaching benefits for the field of neonatology, providing a clinically-relevant testbed in which to develop new therapeutics as well as allowing researchers to control both physiological parameters and embedded cell genotype to explore how to predict spontaneous PDA closure in an effort to avoid unnecessary and risky therapeutic interventions.