SRI Supplement to Reproductive Sciences - Volume 25 Number 1 - March 2018 - 231A

Scientific Abstracts

F-150
Association of Chorionicity with Umbilical Arterial Cord pH in
Twin Pregnancies. Matthew J Blitz†,1 Nontawan Benja-Athonsirikul†,1
Burton Rochelson*,1 Meir Greenberg*,1 Luis A Bracero*.2 1Zucker School
of Medicine at Hofstra/Northwell, North Shore University Hospital,
Manhasset, NY, United States; 2Zucker School of Medicine at Hofstra/
Northwell, Southside Hospital, Bayshore, NY, United States.
INTRODUCTION: A prolonged twin-to-twin delivery interval is
associated with pathologic fetal acidemia and adverse neonatal outcomes
in the second twin. The effect of chorionicity on fetal acidemia is less
certain. The presence of placental vascular anastomoses in monochorionic
(MC) twin pregnancies may alter the acid-base status. Our objective was
to determine whether chorionicity effects the umbilical artery (UA) pH
of the second twin.
METHODS: Retrospective cohort study of all twin pregnancies delivered
at ≥23 weeks of gestational age at a tertiary university medical center
from 2010 to 2016. Patients were included if UA cord gas results were
available for both newborns and histological evaluation of the placenta
was performed after delivery to determine chorionicity. Pregnancies with
an intrauterine fetal demise of either twin prior to labor were excluded.
RESULTS: A total of 728 twin pregnancies were included (629
dichorionic, DC; 99 MC). Among vaginally delivered twins (n=100), the
UA pH of the first twin was higher than the second twin (7.26 vs. 7.24;
p<0.02). In addition, among deliveries in which the first twin delivered
vaginally and the twin-to-twin delivery interval was ≥20 minutes, the first
twin had a significantly higher UA pH than the second twin (7.25 vs. 7.16,
respectively; p<0.007). We found no difference in UA pH between MC and
DC twins for either the first or second twin. Furthermore, this remained
true when comparing cesarean and vaginal deliveries separately. DC
and MC twin pregnancies differed in maternal age (34.0 vs. 32.0 years),
gestational age at delivery (36.1 vs. 35.2 weeks), cesarean delivery rate
(87.3 vs. 79.8%) and birth weights (twin A, 2436 vs. 2267 g; twin B, 2396
vs. 2210 g). MC first twins were more likely than DC first twins to have
1 minute Apgar scores ≤7 (20.2 vs. 14.2%, P<0.04). MC second twins
were more likely than DC second twins to have 5 minute Apgar scores
≤7 (11.1 vs. 4.7%, P<0.01).

231A

CONCLUSION: A number of maternal, fetal and placental factors likely
affect the acid-base status of newborn twins. In our study population,
placental chorionicity was not associated with UA pH in either the first or
second twin. It is possible that populations with a lower cesarean delivery
rate and concomitant prolongation of the twin-to-twin delivery interval
may yield different findings.

F-151
Poor Placental Perfusion is Associated with Placental Endothelial
Dysfunction in the First Trimester. Guy Whitley*, Amanda Host,
Keshika Vishnuthervan, Nicoletta Charolidi, Sandra Ashton, Rose-Marie
Minaisah, Zoe Tryfonos, Basky Thilaganathan, Judith Cartwright. St
George's University of London, London, United Kingdom.
INTRODUCTION: Failure of the placental capillary network to
develop normally has been associated with common pregnancy disorders
including fetal growth restriction (FGR) and pre-eclampsia (PE). Although
the effects are observed at term the problem begins early in gestation.
Investigation of this at a relevant stage have been hindered by difficulties
in identifying pregnancies in the 1st trimester that are affected as well as
the capacity to isolate placental endothelial cells (PEC) at this time. We
have used uterine artery Doppler ultrasound (UtAD) as a proxy measure
of poor placental perfusion and our studies have established a correlation
between high resistance indices (hRI) in 1st trimester uterine arteries
and birth weight due to placental insufficiency. Using this technique we
have isolated PEC from tissue obtained from terminations of 1st trimester
normal pregnancies (nRI) and those at increased risk of developing FGR
and subjected them to a number of comparisons. We hypothesise that the
behaviour of 1st trimester PEC isolated from pregnancies with hRI, and at
increased risk of developing FGR, are compromised leading to the poorly
developed vascular network seen at term.
METHODS: UtAD was performed on women undergoing surgical
termination of pregnancy in the late 1st trimester. Inclusion criteria were:
singleton pregnancy, gestational age 10-14 weeks, normal fetal anatomy
and nuchal translucency thickness with no known maternal medical
condition or history of recurrent miscarriage. PEC were isolated by
enzymatic digestion and selection using CD31-coated magnetic beads.
Cell proliferation, apoptosis and cell motility were assessed by time-lapse
microscopy. Apoptosis was induced with 30ng/ml TNFα. The study had
local Ethics Committee approval and patients gave full informed consent.
RESULTS: PEC isolated from 1st trimester pregnancies with a hRI divide
more slowly in culture. The basal rate of apoptosis in these cells was also
significantly greater than that seen in the nRI group. The pro-apoptotic
stimulus, TNFα, induced significant levels of apoptosis in the hRI PEC
but not nRI PEC. Inhibition of nitric oxide (NO) production by the NO
synthase inhibitor, L-NAME, significantly increased the sensitivity of cells
to apoptotic stimuli from the nRI group but not the hRI group. There was
a small decrease in the motility of PEC isolated from hRI compared to
nRI cells but this did not reach statistical significance.
CONCLUSION: PEC from hRI 1st trimester pregnancies are inherently
different to PEC from a nRI pregnancies and this may contribute to poor
placental vascular development seen in FGR.

F-152
Effect of Marijuana Exposure on Feto-Placental Ratios. Torri D Metz,2
Amanda A Allshouse,1 Michael Varner,4 Marcela Carolina Smid,4 Donald
J Dudley,5 Radek K Bukowski,3 Robert M Silver*.4 1Colorado School of
Public Health, Aurora, CO, United States; 2Denver Health and Hospital
Authority, Denver, CO, United States; 3University of Texas Austin, Austin,
TX, United States; 4University of Utah Health, Salt Lake City, UT, United
States; 5University of Virginia School of Medicine, Charlottesville, VA,
United States.
INTRODUCTION: Marijuana (MJ) use is associated with fetal growth
restriction. Evaluation of feto-placental ratios (FPR) may help elucidate
the mechanism of impaired growth. We aimed to evaluate the association
between maternal MJ use and FPR.
METHODS: Secondary analysis of singleton pregnancies enrolled in a
population-based case-control stillbirth study. Women were categorized
into 4 substance use groups: no tobacco or MJ use, MJ use alone, tobacco

Friday Posters

cells and our studies have shown a role for LIN28 in trophoblast cell
differentiation. Recently, LIN28B was reported to regulate AR signaling
through its actions on Let-7 miRNA in human prostate cancer. This is
significant, as PE patients have significantly increased circulating serum
androgens and increased placental expression of androgen receptor
(AR). The hypothesis of this study is LIN28 regulates AR through Let-7
microRNAs in trophoblast cells, leading to placental differentiation.
METHODS: A human first trimester trophoblast (ACH3P) LIN28B
knockdown cell line was constructed using lentiviral-based pLKO.1-puro
vectors to target LIN28B. LIN28B mRNA and protein knockdown was
confirmed using qRT-PCR and western blot. Small RNAs were extracted
from scramble control and LIN28B knockdown (KD) cells and relative
miRNA levels were analyzed using qRT-PCR.
RESULTS: Let-7e, Let-7f, and Let-7i levels were significantly increased
(p<0.05) in ACH3P LIN28B KD cells compared to non-target scramble
control cells. Quantitative RT-PCR analysis revealed AR levels were
significantly decreased (p = 0.02) in ACH3P LIN28B KD cells compared
to non-target scramble controls. Furthermore, ERVW-1 levels were
increased in ACH3P LIN28B KD cells compared to non-target scramble
control (p = 0.002). Human chorionic gonadotropin (hCG) concentrations
in culture media were determined via ELISA at 24, 48, and 72-hour time
points and were increased in cell culture media from LIN28B KD cells
compared to non-target scramble controls (p < 0.01). ACH3P wild type and
LIN28B KD cells were treated with specific Let-7 mimics to demonstrate
that the effects of LIN28 on AR were due to Let-7.
CONCLUSION: These data suggest that there is a molecular interaction
between LIN28 and AR and understanding the regulation of human
trophoblast differentiation and molecular events that control placental
growth and development is crucial for better understanding the underlying
causes of placental diseases

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
