2014 Oral Presentations
SCIENTIFIC SESSION II: PEDIATRIC SURGERY
PRENATAL MRI FETAL LUNG VOLUMES AND PERCENT LIVER HERNIATION
PREDICT PULMONARY MORBIDITY IN CONGENITAL DIAPHRAGMATIC HERNIA
(CDH)
Zamora IJ, Olutoye OO, Cass DL, Fallon SC, Lazar DA, Cassady CI, Mehollin-Ray AR,
Welty SE, Ruano R, MD, Belfort MA, Lee TC, Texas Children's Hospital and the Michael
E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX
Background
The purpose of this study is to determine whether prenatal imaging parameters are
predictive of postnatal CDH-associated pulmonary morbidity.
Methods
The records of all neonates with CDH treated at our institution from 2004-2012 were
reviewed. Patients without prenatal imaging and who died were excluded. Patients
requiring supplemental oxygen at 30 days of life (DOL) were classified as having
chronic lung disease (CLD). Fetal MRI-measured observed/expected total fetal lung
volume (O/E-TFLV) and percent liver herniation (%LH) were recorded. Receiver
operating characteristics (ROC) curves were applied to assess the prognostic value of
O/E-TFLV and %LH for development of CLD. A multivariate logistic regression analysis
was performed to determine significant imaging predictors of clinically relevant postnatal
pulmonary outcomes.
Results
Of 172 neonates with CDH treated during this period, 108 had fetal MRI data available.
Of these 108, overall survival was 76%; 82% (89/108) were alive at DOL 30, 46 (52%)
of which had CLD. Neonates with CLD had significantly lower mean O/E-TFLV (30
vs.42%; p=0.001) and higher %LH (21.3±2.8 vs.7.1±1.8%; p<0.001) compared to
neonates without CLD. Using ROC analysis the best cutoffs in predicting CLD were an
O/E-TFLV of 35% (AUC=0.74; p<0.001) and a %LH of >20% (AUC=0.78; p<0.001).
Using Life Table analysis, infants with O/E-TFLV<35% (p=0.004) and a %LH>20%
(p=0.005) had a significantly longer time to extubation. On logistic regression, an O/ETFLV<35% and a %LH>20% were highly associated with indicators of long-term
pulmonary sequelae. On multivariate analysis, %LH was the strongest predictor of longterm pulmonary sequelae in patients with CDH (OR: 10.96, 95%CI: 2.5–48.9, p=0.002).
Conclusion
Prenatal measurement of O/E-TFLV and %LH are predictive of CDH pulmonary
morbidity and can aid in establishing parental expectations of postnatal outcomes,
comparing inter-institutional risk-adjusted outcomes, and helping to optimize
management of neonates with this challenging disease.
TRANSFORMING GROWTH FACTOR BETA-3 ALTERS HUMAN INTESTINAL
SMOOTH MUSCLE CELL FUNCTION AND GENE EXPRESSION
D.M. Hook-Dufresne, D.M. Hook-Dufresne, D. Ke, A. Olsen, C.S. Cox, S.D. MooreOlufemi, University of Texas Health Science Center Houston
Background
Gastroschisis-related intestinal dysfunction (GRID) is currently the leading cause of
pediatric intestinal failure. Recent data from our lab demonstrated that patients with
gastroschisis have elevated expression of transforming growth factor beta-3 (TGF-β3) in
their intestinal smooth muscle cell layers. The purpose of this study was to evaluate the
effects of TGF-β3 on human intestinal smooth muscle cell (hiSMC) function and
phenotypic gene expression.
Methods
Human intestinal smooth muscle cells (hiSMCs) were incubated ± fetal bovine serum
(FBS) ± 100ng/ml of TGF-β3 for 6, 24, 48 and 72 hours, using 6 hours as our baseline.
The effects of TGF-β3 on hiSMC motility, contractility, myosin light chain
phosphorylation (MLC-P) and contractile versus synthetic phenotype gene expression
were measured using a Transwell migration system, a collagen gel contraction assay,
Western blot and RT-PCR analysis.
Results
TGF-β3 significantly decreased hiSMC migration and significantly stimulated collagen
gel contraction at 24, 48 and 72 hours (p-value < 0.05). MLC-P was markedly elevated
at 6 and 24 hours, but had decreased by 72 hours after exposure to TGF-β3. Compared
to our 6 hour time point, contractile protein gene expression was increased at 24, 48
and 72 hours, while synthetic protein gene expression was unchanged when compared
to controls.
Conclusion
Our study suggests that TGF-β3 may alter hiSMC function by phosphorylating MLC
early contributing to maximum smooth muscle cell contraction and decreased cell
migration. Exposure of hiSMCs to TGF-β3 was associated with a contractile phenotype.
These effects of TGF-β3 on hiSMCs may, in part, explain the pathophysiology of GRID.
Further characterization of the TGF-β3 signaling pathway(s) involved may provide a
foundation for identifying novel therapeutics to improve hiSMC dysfunction in GS
patients.
EFFECT OF INTRAUTERINE GROWTH RESTRICTION AND PREMATURITY ON
PERIPHERAL NEONATAL REGULATORY T CELLS
D Mukhopadhyay, L Weaver, R Tobin, J S Thomas, M K Newell-Rogers, L Perger, Scott
& White Memorial/Texas A&M University
Background
Necrotizing enterocolitis (NEC) is the most common surgical emergency in newborns,
accompanied by harmful local and systemic pro-inflammatory response. Low birth
weight and pre-term newborns are at highest risk of developing NEC. Regulatory T cells
(Treg), a subset of CD4+ T lymphocytes defined by expression of FoxP3 and CD25, are
potent suppressors of inflammation. Diminished Tregs in infants may contribute to the
pathogenesis of necrotizing enterocolitis (NEC). The aim of this study was to
characterize independent effects of gestational age and intrauterine growth restriction
(IUGR) on peripheral Tregs in neonatal cord blood.
Methods
Cord blood of 200 newborns was collected between June 2012 and January 2013 and
mononuclear cells were analyzed using four-color flow cytometry. Tregs (CD3+, CD4+,
CD25high, FoxP3high) were identified, and FoxP3 mean fluorescence intensity (MFI)
was measured. Suppressive index (SI) was calculated as MFI/Treg for individual Treg
suppressive capacity. Mann-Whitney and Kruskall Wallis tests were used for statistical
analysis.
Results
In the presence of IUGR, term babies (n=18, SGA) had a decreased Treg proportions of
CD4+T cells compared to appropriate weight counterparts (n=80, AGA) (median
(interquartile range) 7%(4-10) in AGA vs. 6%(1-8) in SGA, p=0.0121) but equivalent SI
(67(33-158) in AGA vs. 81(41-151) in SGA, p=0.6905). In appropriate weight babies,
Tregs decreased with increasing gestational age (median (interquartile range) 10 (8-13)
in early third trimester (n=13), 11 (6-17) in late third trimester (n=33), 7 (4-10) in term
(n=80), p=0.0025) with a concurrent increase in SI (25(13-71) in early third trimester,
35(23-80) in late third, 67(33-158) in term, p=0037).
Conclusion
IUGR is correlated with fewer circulating Tregs and prematurity with lower suppressive
function, compared to term appropriate weight infants. This combined effect of fewer
and less functional Tregs seen in peripheral blood may predispose this cohort of
newborns to diseases of dysregulated inflammatory responses such as NEC.