SRI Supplement to Reproductive Sciences - Volume 25 Number 1 - March 2018 - 162A

162A

Reproductive Sciences Vol. 25, Supplement 1, March 2018

T-157
Extravillous Trophoblast Cell Galectin 13 and Endoglin Levels Are
Differentially Correlated in Association with Fetal Growth Restriction/
Preeclampsia: A Case-Control Study. Steven J Korzeniewski,2 Sascha
Drewlo,1 D Randal Armant.2 1Michigan State University, Grand Rapids,
MI, United States; 2Wayne State University School of Medicine, Detroit,
MI, United States.
INTRODUCTION: Trophoblast Retrieval and Isolation from the
Cervix (TRIC) enables noninvasive collection of extravillous trophoblast
(EVT) like cells from ongoing pregnancies at 5-20 weeks' gestation. We
demonstrated that EVT cell proteins can discriminate between fetuses that
later developed fetal growth restriction or were exposed to preeclampsia
(FGR/PE) and a control group. Unlike several other targeted proteins,
median galectin 13 levels were no different between these groups. Since
galectin 13 might facilitate conversion of spiral arteries or otherwise
influence the perfusion of blood to the placenta along multiple pathways,
we sought additional information.
METHODS: EVT cells were obtained by TRIC in 200 women at 5 to
20 weeks of gestation. Pregnancies that developed FGR/PE were cases;
controls matched on gestational age at sample were women who had
uncomplicated pregnancies. Proteins levels were semi-quantified by
immunofluorescence microscopy.
We tested the null hypothesis that EVT cell galectin 13 levels are not
correlated with other malplacentation-associated proteins. There was >
80% statistical power to detect a Spearman's rank correlation coefficients
(r) > 0.50 among controls; among cases there was > 80% to detect a
correlation > 0.70.
RESULTS: EVT cell galectin 13 levels among cases (n=12) were
significantly correlated with ENG (r = -0.80, p=0.002) and with PAPPA
(r = 0.70, p=0.01); the weakest correlations among cases were between
galectin 13 and AFP (r = -0.11, p=0.73) and PGF (r = 0.19, p=0.56).
Among controls (n=28), galectin 13 levels were least correlated with ENG
(r = 0.40, p=0.04) and FLT1 (r = 0.37, p=0.051), while its correlations
with PAPPA (r = 0.71, p < 0.0001) and PGF (r = 0.70, p < 0.0001) were
the strongest.
ENG levels differed among cases and controls depending on the cooccurrence of low quartile galectin 13 (interaction p=0.002; R2 0.57 and
Adjusted R2 0.51); least squares mean ENG levels were significantly
higher among cases than controls only if galectin 13 was low [Figure 1].
Adjustment for potential confounders did not affect these results [i.e.,
fetal sex, gestational age at sample].
CONCLUSION: We demonstrated that TRIC provides a novel platform
for profiling the coordination among EVT cell protein expression
associated with FGR/PE. Further study is warranted in a larger prospective
sample using advanced techniques to quantify additional proteins.
*Figure(s) will be available online.

T-158
Dysregulation of Integrin alpha6 - Laminin Binding May Cause
Trophoblast Over-Invasion in Placenta Accreta. Christina M Duzyj,3
Bingbing Wang,3 Marina Chekmareva,3 Debra Heller,2 Nicholas Illsley.1
1
Hackensack University Medical Center, Hackensack, NJ, United States;
2
Rutgers New Jersey Medical School, Newark, NJ, United States; 3Rutgers
Robert Wood Johnson Medical School, New Brunswick, NJ, United States.
INTRODUCTION: Placental invasion is known to involve integrin extracellular matrix (ECM) binding between trophoblast and decidua,
particularly integrin alpha 6 - laminin binding, and integrin alpha
5 - fibronectin binding. However, placenta accreta involves direct
juxtaposition of placental villi and myometrium without intervening
decidua. We have visualized an abundance of Type IV collagen, a
component of ECM, at the myometrial-villous interface in accreta. We
hypothesized then that aberrancy of decidual ECM signaling impacts
trophoblast over-invasion in accreta.
METHODS: Pathologic specimens of paraffin embedded placenta accreta
were retrieved (n=4). Sections were taken from the myometrial-placental
junction and from normal myometrium for comparison. Placental bed
sections from non-accreta postpartum hysterectomies were used for
comparison (n=5). Immunohistochemical staining was performed for

Scientific Abstracts

integrin alpha 5 and alpha 6, HLA-G (extravillous trophoblast marker),
type IV collagen, fibronectin and laminin. Semi-quantitative H-scores
were assigned and median values reported.
RESULTS: All accreta specimens demonstrated placental villi, an absence
of decidua, and extravillous trophoblast within an ECM containing
Type IV collagen and fibronectin at the myometrial junction. Laminin
was expressed by syncytiotrophoblast (Sync), and less abundantly
by extravillous trophoblast of accreta samples. Integrin alpha 5 was
abundantly present on Sync and extravillous trophoblast surface, as
well as less abundantly surrounding myometrial fibers in accreta and
normal biopsies. Integrin alpha 6 was present on decidua cell surface
and cytoplasm on placental bed biopsies only, and had no appreciable
staining on accreta specimens.
CONCLUSION: This observational study demonstrates that Integrin
alpha 6 is absent at the myometrial junction in cases of placenta accreta,
causing laminin in the invading trophoblast to lack a receptor for anchoring
and attachment. This suggests that integrin alpha 6 in the decidua may
serve as a "stop signal" for invading trophoblast, the absence of which
promotes the trophoblast over-invasion appreciated in placenta accreta.
*Figure(s) will be available online.

T-159
Divergent Effects of BMP Signaling in Early Mouse and Human
Trophoblast. Jennie Au†, Francesa Soncin, Anna Wakeland, Kanaga
Arul Nambi Rajan, Katherine K Nelson, Mana M Parast. UC San Diego,
La Jolla, CA, United States.
INTRODUCTION: Bone morphogenetic protein (BMP)-4 is highly
expressed in extra-embryonic ectoderm (ExE, early trophoblast). Its main
known effect is on the epiblast, inducing formation of primitive streak
(early mesoderm); however, autocrine effects of BMP4 on ExE-derived
tissue have not been studied in detail. We aimed to evaluate the effects of
BMP4 on differentiation of both mouse trophoblast stem (TS) cells and
human early gestation cytotrophoblast (CTB).
METHODS: We examined RNA expression of BMP4 and BMP receptors
(1A, 1B and 2) in both mouse TS cells and human primary first trimester
cytotrophoblast (CTB) by qRT-PCR. Next, we evaluated the effect of
BMP4 treatment on mouse TS cell differentiation and human first trimester
placental explants. Mouse TS cell differentiation was evaluated by qPCR
for lineage-specific markers. Human placental explants were evaluated by
staining for Ki67, as a marker of proliferation, and Phospho-Smad1/5/8,
as a marker of BMP4 signaling. To further examine the role of BMP4, we
generated mouse TS cell clones overexpressing BMP4, and also evaluated
BMP4 signaling in mouse TS cells lacking the nutrient sensor, Sirtuin-1.
RESULTS: BMP4, BMPR1A and BMPR2 were highly expressed in
undifferentiated mouse TS cells and isolated early gestation human
CTB. BMP4 RNA levels decreased significantly following day 1 of TS
cell differentiation in vitro. Both continuous exogenous BMP4 treatment
and BMP4 overexpression blunted TS cell differentiation, decreasing all
lineage-specific terminal differentiation markers, including Tpbpa, Pl-II,
and SynA. However, in TS growth media, supplemented with FGF4,
BMP4 was not sufficient to maintain TS cells in their undifferentiated
state in the absence of Activin-A. Undifferentiated mouse TS cells
lacking Sirtuin-1, which have a phenotype consisting of slow growth
and decreased TS markers (including Esrrb), expressed reduced BMP4
RNA as well as reduced total and phosphorylated forms of Smad1/5/8.
Conversely, human placental explants treated with BMP4 showed reduced
proliferation, based on Ki67 staining; BMP4 signaling was confirmed in
the CTB layer by staining for phosphorylated Smad1/5/8.
CONCLUSION: While BMP4 signaling blunts trophoblast differentiation
in the mouse, it appears to decrease proliferation in primary human CTB.
Since BMP4 also induces terminal trophoblast differentiation in human
embryonic stem cell-derived CTB, we propose the BMP4 has divergent
roles in mouse and human trophoblast differentiation.

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