Naomi Smith
Research Mentor: Alvaro Rojas-Peña
Mentor Department: Department of Surgery-Transplantation, Medicine
Author(s): Naomi Smith, Ninette Musili, Joseph Church, Alvaro Rojas-Peña
Session: Session 6 (3:00 PM – 3:50 PM)
Presentation Type: Poster 35
Abstract
Objective: Congenital Diaphragmatic Hernia (CDH) is a rare congenital anomaly characterized by an diaphragmatic defect with herniation of abdominal contents into the chest, and is associated with pulmonary hypertension, hypoplasia, and cardiac dysfunction. Morbidity and mortality are high in this population, especially in the 30% of neonates requiring extracorporeal life support (ECLS), with half these patients dying. A potential alternative approach to ECLS in this population would be an artificial placenta (AP) consisting of veno-venous ECLS, preservation of fetal circulation, avoidance of mechanical ventilation and perfluorocarbon (PFC) lung management. We aimed to establish the lung morphological changes affected by AP support in lambs with CDH. Methods: CDH defect creation was completed with laparotomy, hysterotomy, and stomach placement in the chest cavity at 65-75 days estimated gestational age (EGA). Lambs were then delivered at 130-140 (EGA; term = 145 days). Healthy control (HC, no defect created; n=6) and CDH control (CC, with defect; n=4) lambs underwent immediate sacrifice after delivery. AP support was initiated in n=4 lambs and maintained for a goal of 7 days, after which lambs were sacrificed. At necropsy, bilateral lungs were harvested, then 1cm of the distal most left lung was resected and sent to pathology for hematoxylin and eosin staining. Slides were digitized using a Nikon Ti2 microscope at 10X magnification with brightfield microscopy. For each slide 9 regions of interest at 500 x 500 pixels were selected using FIJI(ImageJ) from right, center and left regions as well as superior, inferior and center regions. These regions were then evaluated using a validated morphometric plugin for evaluation of the volume density of alveolar septa (VVsep), the mean linear intercept of the airspaces (Lm), and the mean transsectional wall length (Lmw). ANOVA was used to compare means between the healthy control, disease control and artificial placental support for the above-mentioned values. Results: The first three AP lambs in the series experienced instability between support days 4-6 necessitating compassionate sacrifice; the fourth lamb was maintained for 7 days with stability throughout. Only the fourth lamb was included in our analysis (n=1) as the other three were found to have interstitial pneumonia and septic emboli that precluded other morphometric analysis. On morphometric analysis, the mean linear intercept of the airspaces was 28.01±4.663microns [25.42-30.59] in the HC group, 30.42± 23.15microns [18.52-42.32] in the CC group and 33.39±6.16 [18.08-48.69] in the AP group (p=0.16). The mean transactional wall length was 11.30±2.884microns [9.69-12.89] in the HC group, 23.77±11.06microns [18.09-29.46] in the CC group, and 19.85±8.49microns [1.2-40.95] in the AP group(p<0.0001). Airspace volume was 0.28±0.05% [0.255-0.31] for the HC, 0.47±0.14% [0.39-0.54] for the CC, and 0.36±0.11% [0.07-0.66] for the AP (p<0.0004). Conclusion Though results are preliminary with n=1 of 7 days of AP support, these results suggest improvement in lung morphology after 7 days of support compared to CDH control; further replicates will be needed to confirm these findings.
