Abstract Introduction Pediatric pulmonary hypertension (PH) has high morbidity and mortality, with an estimated 5-year survival of 75%. Clinical trials of pediatric PH face numerous barriers, including heterogeneity of the patient population, low enrollment, and inconsistent measures of efficacy. At the same time, survival of infants born extremely preterm and infants with congenital heart disease, the most common populations to develop pediatric PH, has been increasing in recent decades. Research on the pathophysiology and development of novel therapies requires new translational tools. We hypothesized that it would be feasible to culture primary pulmonary endothelium from pediatric patients undergoing isolated right heart catheterization using methods described in adults. Methods This is an IRB-approved, prospective sample of pediatric patients aged 0 to 18 who were undergoing catheterization in the pediatric interventional cardiac catheterization lab. Routine catheterization procedures were followed including pulmonary capillary wedge pressure measurement with a 5 or 6 French Balloon Wedge Catheter. At the conclusion of the procedure, the balloon catheter was withdrawn into the sheath, and the sheath and catheter were removed together. The catheter tip was advanced out of the sheath into endothelial growth media that was warmed to 37C. The catheter tip was placed into a single well of a 24-well plate that had been coated with cell attachment solution and incubated with media from the collection tube. The remaining media was spun down and the pellet resuspended and plated in a separate well. Cells were analyzed for markers of endothelial lineage at passage 3 or 4. Results Three of four attempted collections in patients undergoing isolated right heart catheterization were successful (75%). Cells were first visible 2-10 days after collection and were confluent within 2-3 weeks. In all three samples analyzed, more than 98% of cells were CD31+/CD146+/CD45- and 85-95% viable by flow cytometry. Fixed cells stained positive for CD31, VE-Cad, and vWF. Lastly, cells demonstrated uptake of acetylated LDL (ac-LDL). Conclusion Isolation and culture of endothelium from catheter tips in right heart catheterization is feasible in pediatric patients. Cells grown from three pediatric patients were viable, exhibited multiple markers of endothelial lineage, did not express CD45, a marker of hematopoietic lineage, and exhibited uptake of ac-LDL, a feature of endothelium and macrophages. We speculate that further validation, characterization and phenotyping of these cells along with identifying an appropriate control may provide insights into the pathophysiology of pediatric pulmonary hypertension. This abstract is funded by: None
Mathias et al. (Fri,) studied this question.