SRI Supplement to Reproductive Sciences - Volume 25 Number 1 - March 2018 - 209A

Scientific Abstracts

F-082
Effects of Antenatal Synthetic Glucocorticoid Exposure on Oxidative
Stress in the Fetal Liver and Placenta. Susmita Sarkar†, Alexandros
Mouratidis†, Vasilis Moisiadis†, Alisa Kostaki†, Stephen G Matthews*.
University of Toronto, Toronto, ON, Canada.
INTRODUCTION: Antenatal synthetic glucocorticoid (sGC) therapy
promotes lung development in preterm (<34 weeks) infants and reduces
the associated risk of respiratory distress syndrome (RDS). However,
antenatal sGC use has been associated with altered long-term metabolic
outcomes. In adult rats, exposure to glucocorticoid lead to increased
levels of oxidative stress in the liver. Prolonged imbalance between the
reactive oxygen species (ROS) and antioxidant defence mechanisms lead
to oxidative damage, such as protein carbonylation. We hypothesize that
prenatal sGC therapy will promote oxidative stress by decreasing the
gene expression of one or more enzymes from the antioxidant defence
mechanism in the fetal liver and placenta, and will lead to increased
protein carbonylation in these tissues.
METHODS: Pregnant guinea pigs were treated with the sGC
betamethasone (1mg/kg) or equal volume of saline (vehicle) on gestational
days (GD) 40/41 and 50/51. Fetal liver and placenta tissues were extracted
on GD52, and stored at -80°C. qRT-PCR was used to determine the mRNA
expression of the following antioxidant enzymes: glutathione peroxidase
(Gpx4, Gpx7), superoxide dismutase (Sod1 and Sod2), thioredoxin (Txn),
peroxiredoxin (Prdx3, Prdx6), catalase (Cat), glucose 6 dehydrogenase
(G6Pd), and NADPH quinone dehydrogensase 1 (NQO-1). Protein
carbonylation was measured using a commercially available kit (Abcam
Inc). Data were analyzed using the student's t-test.
RESULTS: In the liver, prenatal exposure to sGC resulted in a decrease
in Prdx6 mRNA levels in male fetuses (p=0.02), and a trend towards a
decrease in Sod1 expression in females (p=0.06). There were no effects
of sGC treatment on antioxidant mRNA expression in the placentae from
male or female fetus. There were also no effects of sGC treatment on
protein carbonylation in the fetal liver or placenta.
CONCLUSION: The down regulation of antioxidant enzymes in the liver
after sGC exposure supports our hypothesis that sGC decreases activity
of the the antioxidant defence mechanisms. Interestingly, the nature of
these effects appeared sex-specific. However, sGC exposure did not affect
antioxidant enzyme expression in the placenta or protein carbonylation in
the liver or placenta, which is contrary to our hypothesis. These results
suggest limited effects of acute sGC exposure on oxidative stress pathways
in the liver and no acute effect in the placenta. It is possible that there is a
delay in the emergence of effects following sGC exposure and follow-up
studies are being undertaken in juvenile offspring.

209A

F-083
Modeling the Cerebral Transcriptomic Response to Umbilical Cord
Occlusion Reveals Different Responses in the Late-Gestation Fetal
Sheep. Miguel A Zarate†, Beronica A Ocasio†, Charles E Wood*.
University of Florida, Gainesville, FL, United States.
INTRODUCTION: Umbilical cord occlusion (UCO) is a severe type
of fetal asphyxia associated with a host of negative fetal and neonatal
outcomes. Many studies have addressed the consequences of fetal hypoxia
but little is known about the core molecular mechanisms underlying
the outcomes in late gestation. Here, we aimed to model the molecular
effects of UCO through gene expression profiling in different ovine brain
regions at two different time points. We hypothesize that hypoxia induced
by UCO produces a similar fetal transcriptomic profile among various
cerebral regions (cortex, hypothalamus, and hippocampus) and kidneys.
METHODS: An extravascular occluder was placed around the umbilical
cord in chronically catheterized fetal sheep (125 d gestation). A 30-min
transient UCO decreased fetal PaO2 by 50 % (UCO and control, n=4/
group). Fetal organs were collected at 1 and 24 hrs post-UCO. mRNA
were extracted and hybridized to ovine Agilent 15.5k microarray. Data
were normalized, corrected, filtered, and analyzed using the Limma and
WGCNA packages for R. Differentially expressed genes (DEGs) were
identified at P<0.05. Functional properties of these genes were further
analyzed using the Gene Set Enrichment Analysis from the WEB-based
Gene SeT AnaLysis Toolkit (WebGestalt).
RESULTS: The initial effects to UCO (1 hr) included a cascade of changes
in cellular processes and genetic regulation, including the activation of
DNA repair pathways and histone modifications compared to control.
DEGs shared similarities among brain regions and kidneys in this early
response. After 24 hrs, comparative analyses of DEGs showed a shift
toward altered metabolic processes, as well as effects on the immune
response. However, most DEGs were found to be unique to each fetal
organ. The fetal cerebral cortex showed the highest number of genes
differentially expressed across both time points.
CONCLUSION: Overall, these results suggest that umbilical cord
occlusion produces two different patterns of transcriptomic responses
at 1-hour and 24-hour time points, and these responses further differ
between the cerebral cortex, hippocampus, hypothalamus, and kidneys
24 hrs post insult.

F-084
When a "Double Bubble" is Identified: What is the Likelihood of
Duodenal Atresia and Genetic Abnormality? Juliet C Bishop†, Eric
Jelin, Jena Miller, Clark Johnson, Karin Blakemore, Angie C Jelin*. Johns
Hopkins School of Medicine, Baltimore, MD, United States.
INTRODUCTION: The "double bubble" sign is an ultrasonographic
finding that is most often associated with duodenal atresia. However, other
causes of upper intestinal obstruction, including genetic abnormalities,
need to be considered in prenatal diagnosis. We sought to evaluate the
diagnostic accuracy of ultrasonographic prenatally identified "double
bubble" sign and the associated genetic etiologies.
METHODS: We examined a retrospective cohort series including all cases
of suspected fetal duodenal atresia based on prenatal ultrasonographic
"double bubble" sign at a single center between January 1, 2008 and
June 30, 2017. Postnatal diagnosis was determined by review of operative
reports. Cases were further investigated for associated genetic etiologies
by cytogenetic analysis, molecular analysis, and/or clinical diagnosis.
RESULTS: Eighteen fetuses evaluated by prenatal ultrasound were found
to have sonographic evidence of duodenal atresia with a "double bubble"
sign. Gestational ages of initial sonographic evaluation at our center were
19 + 6/7 to 36 + 4/7 weeks. Two cases delivered at outside hospitals and
one case with demise without confirmatory diagnosis were excluded.
In all 15 included cases, postnatal duodenal atresia was confirmed by
direct examination during surgical corrective procedures. Additional
intraoperative findings included gastric volvulus in one case and annular
pancreas in five other cases. A genetic etiology of duodenal atresia was
identified in 7 cases: 5 cases of trisomy 21 and 2 cases of heterotaxy, one

Friday Posters

and 1 singleton pregnancy). These animals had not been used for any
other purpose, had not been catheterized, and were not treated with
antibiotics. We collected tissues and fluids (lung, spleen, placenta,
meconium, amniotic fluid) using sterile technique. DNA extracted from
these tissues were subjected to PCR with universal primers 341F and
806R and barcoded using Illumina MiSeq adapters.
RESULTS: 88 of 90 tissue samples contained measurable bacterial
DNA: only tissues with measurable amounts of bacterial DNA were
sequenced. MiSeq profiles were trimmed 544 samples, with an average
of 250,145 reads per sample. Sequence analysis revealed a broad diversity
of bacterial genera, including Achromobacter, Streptococcus, Delftia, and
Staphylococcus. Once the bacterial populations were known, non-metric
multidimensional scaling (NMDS) was used to determine sorting of
bacteria by tissue, with cerebral cortex and placenta having overlapping
populations of bacteria.
CONCLUSION: We conclude that normal fetal tissues contain bacterial
DNA. While the presence of bacterial DNA does not necessarily
demonstrate the presence of live bacteria, the results are consistent with
the concept that bacteria sort to specific "niches" within the fetus.

Reproductive Sciences Vol. 25, Supplement 1, March 2018
Table of Contents for the Digital Edition of SRI Supplement to Reproductive Sciences - Volume 25 Number 1 - March 2018
