Faculty Bibliography

Fetal endoscopic tracheal occlusion (FETO) is an emerging surgical therapy for congenital diaphragmatic hernia (CDH). Ovine and rabbit data suggested altered lung epithelial cell populations after tracheal occlusion (TO) with transcriptomic signatures implicating basal cells. To test this hypothesis, we deconvolved mRNA sequencing (mRNA-seq) data and used quantitative image analysis in fetal rabbit lung TO, which had increased basal cells and reduced ciliated cells after TO. In a fetal mouse TO model, flow cytometry showed increased basal cells, and immunohistochemistry demonstrated basal cell extension to subpleural airways. Nuclear Yap, a known regulator of basal cell fate, was increased in TO lung, and Yap ablation on the lung epithelium abrogated TO-mediated basal cell expansion. mRNA-seq of TO lung showed increased activity of downstream Yap genes. Human lung specimens with congenital and fetal tracheal occlusion had clusters of subpleural basal cells that were not present in the control. TO increases lung epithelial cell nuclear Yap, leading to basal cell expansion.

PURPOSE:The purpose of the study is to examine MRI findings of the brain and spine on prenatal and postnatal MRI following intrauterine repair of open spinal dysraphism (OSD) by open hysterotomy and fetoscopic approaches. MATERIALS AND METHODS:This study is a single-center HIPAA-compliant and IRB-approved retrospective analysis of fetal MRIs with open spinal dysraphism from January 2011 through December 2018 that underwent subsequent prenatal repair of OSD. RESULTS:Sixty-two patients met inclusion criteria: 47 underwent open repair, and 15 underwent fetoscopic repair, with an average gestational age of 22.6 ± 1.4 weeks at initial MRI. On postnatal MRI, spinal cord syrinx was seen in 34% (16/47) of patients undergoing open versus 33.3% (5/15) undergoing fetoscopic repair (P = 0.96). Postnatally, there was no significant difference in hindbrain herniation between the open versus fetoscopic repair groups (P = 0.28). Lateral ventricular size was significantly larger in the open (20.9 ± 6.7 mm) versus the fetoscopic repair (16.1 ± 4.9 mm) group (P = 0.01). CONCLUSION:Though lateral ventricular size in the open repair group was larger than the fetoscopic repair group, this can likely be explained by initial selection criteria used for fetoscopic repair. Other postoperative imaging parameters on postnatal MRI were not significantly different between the two groups.

BACKGROUND:Fetal tracheal occlusion (TO) is an experimental therapeutic approach to stimulate lung growth in the most severe congenital diaphragmatic hernia (CDH) cases. We have previously demonstrated a heterogeneous response of normal fetal rabbit lungs after TO with the appearance of at least two distinct zones. The aim of this study was to examine the fetal lung response after TO in a left CDH fetal rabbit model. METHODS:Fetal rabbits at 25 d gestation underwent surgical creation of CDH followed by TO at 27 d and harvest on day 30. Morphometric analysis, global metabolomics, and fluorescence lifetime imaging microscopy (FLIM) were performed to evaluate structural and metabolic changes in control, CDH, and CDH + TO lungs. RESULTS:Right and left lungs were different at the baseline and had a heterogeneous pulmonary growth response in CDH and after TO. The relative percent growth of the right lungs in CDH + TO was higher than the left lungs. Morphometric analyses revealed heterogeneous tissue-to-airspace ratios, in addition to size and number of airspaces within and between the lungs in the different groups. Global metabolomics demonstrated a slower rate of metabolism in the CDH group with the left lungs being less metabolically active. TO stimulated metabolic activity in both lungs to different degrees. FLIM analysis demonstrated local heterogeneity in glycolysis, oxidative phosphorylation (OXPHOS), and FLIM "lipid-surfactant" signal within and between the right and left lungs in all groups. CONCLUSIONS:We demonstrate that TO leads to a heterogeneous morphologic and metabolic response within and between the right and left lungs in a left CDH rabbit model.

PURPOSE/OBJECTIVE:Primary closure is often inadequate for large congenital diaphragmatic hernia (CDH) and necessitates repair by prosthetic patch or autologous muscle flap. Our aim was to evaluate outcomes of open patch versus flap repair, specifically diaphragmatic reherniation. METHODS:A retrospective review (IRB #2017-6361) was performed on all CDH patients repaired from 2005 to 2016 at a single academic children's hospital. Patients were excluded from final analysis if they had primary or minimally invasive repair, expired, or were lost to follow-up. RESULTS:Of 171 patients, 151 (88.3%) survived to discharge, 9 expired after discharge and 11 were lost to follow up, leaving 131 (86.8%) long-term survivors. Median follow-up was 5 years. Open repair was performed in 119 (90.8%) of which 28 (23.5%) underwent primary repair, 34 (28.6%) patch repair, and 57 (47.9%) flap repair. Overall, 6/119 (5%) patients reherniated, 1/28 (3.6%) in the primary group, 3/34 (8.8%) in the patch group, and 2/57 (3.5%) in the flap group. Comparing prosthetic patch to muscle flap repair, there was no significant difference in the number of patients who recurred nor time to reherniation (3 vs. 2, p = 0.295; 5.5 ± 0.00 months vs. 53.75 ± 71.06 months, p = 0.288). One patient in the patch group recurred twice. CONCLUSIONS:Both muscle flap and patch repair of large CDH are feasible and durable with a relatively low risk of recurrence.

Despite unfavorable outcomes during the early experience with in utero intervention for congenital hydrocephalus, improvements in prenatal diagnosis, patient selection, and fetal surgery techniques have led to a renewed interest in fetal intervention for congenital hydrocephalus. Research studies and clinical evidence shows that postnatal cerebrospinal fluid diversion to release intraventricular pressure and cerebral mantle compression usually arrives late to avoid irreversible brain damage. Make sense to decompress those lateral ventricles as soon as possible during the intrauterine life when hydrocephalus is antenatally detected. We present a historical review of research in animal models as well as clinical experience in the last decades, traveling until the last years when some research fetal therapy groups have made significant progress in recapitulating the prenatal intervention for fetuses with congenital obstructive hydrocephalus.

Our study focuses on the development and characterization of a self-expanding, watertight and biodegradable patch for fetoscopic myelomeningocele (MMC) prenatal repair. We fabricated poly(l-lactic acid) (PLA) and poly(ɛ-caprolactone) (PCL) blend films by solution casting. Formulation c with average glass transition temperature of 37.6 ± 1.2°C was chosen for temporospatial recovery. Favorable results from surface studies reflected homogeneous dispersion of polymers in the blend. The cytotoxicity was studied in human foreskin fibroblasts. The blend film was cytocompatible, evidenced by matching percentage of live cells in exposed and control solutions. Subsequently, liquid water permeability experiments confirmed watertight nature of films. Finally, in vitro degradation was investigated in phosphate buffered saline (PBS) and amniotic fluid (AF) separately for 16 weeks. Similar weight loss (n = 6, p = 0.912) and significantly different (n = 3, p = 0.025) surface roughness was observed in PBS and AF, respectively, at 16 weeks. Functional group analysis displayed increasing carbonyl and hydroxyl bonds in PBS and AF, respectively, over time, indicating progression of hydrolytic degradation. Favorable characterization results provide strong evidence to employ PLA-PCL blend films as surgical patches in fetoscopic MMC repair. Designed patch serves as standalone system to successfully tackle impending hurdles of MMC repair and proves to be a superior alternative compared to existing patches. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 295-305, 2019.