SRI Supplement to Reproductive Sciences - Volume 25 Number 1 - March 2018 - 119A

Scientific Abstracts

T-027
Functional Interactions between Estrogen and Relaxin Signaling
in the Myometrium. Sudeshna Tripathy†, Anusha Nagari, Mala
Mahendroo*, William Lee Kraus*. University of Texas Southwestern
Medical Center, Dallas, TX, United States.
INTRODUCTION: The complex integration of molecular signaling
events in the uterus is critical to understanding fertility and pregnancy
utcomes. The hormone progesterone plays a predominant role in uterine
quiescence, while hormone estrogen (E2) plays a key role in uterine
contractility. Many of E2's actions via its receptor, ERa, occur in the
context of activation of the signaling pathways controlled by the peptide
hormone relaxin (Rln) during term pregnancy in mice. However, the
extent, functional outcomes, and molecular mechansims by which
molecular cross-talk between E2 and Rln is achieved to ensure optimal
myometrial function is unknown. We hypothesized that Rln signaling
in the myometrium alters or regulates a parturition-specific repetoire of
ERa binding sites (cistrome) that results in a cell specific and dynamic +/ERa-regulated transcriptome that controls downstream biological events.
METHODS: We used myometrial tissue from ovariectomized mice
treated with E2+Rln or either hormone alone, or from pregnant mice
+/- with or without targeted mutations in the relaxin receptor, Rxfp1. We
generated high quaity cistromic (ERa, H3K27ac, and H3K4me1 ChIPseq) and transcriptomic (RNA-seq) data sets in the ovx mice model. Then
we examined the functional interplay between E2- and Rln- dependent
signaling pathways by analyzing various signaling molecules downstream
of Rln-Rxfp1 by Western blotting.

119A

RESULTS: Our RNA-seq data sets have uncovered a unique
transcriptome signature regulated by the individual and/or combined
actions of E2/Rln in the myometrium. In addition, we observed that many
of the binding sites were depleted in presence of Rln, although marker of
enhancers (i.e. H3K27ac and H3K4me1) were still enriched at those sites.
Futher analysis to correlate the findings to the physiological relevance
in the myometrium at term is in progress. We also observed increased
Erk1/2 activation with E2+Rln, greater than activation with either hormone
alone. This was reciprocated in wild-type mice during term pregnancy,
in contrast to te Rxfp1 knockout mice. Interestingly, Erk1/2 activity was
localized primarily to the cytoplasm of myometrial cells. We are now
performing Erk1 and Erk2 localization studies to access their potential
roles as a downstream mediators of Rln signaling that alters chromatin
accessibility to direct the ERa-dependent transcription.
CONCLUSION: Our goal is to leverage a novel biological platform for
genomic assessment with the potential to elucidate hormonal collaborative
pathways in the myometrium for successful fertility.

T-028
In Vitro Myometrial Contractility in Gestational Diabetes Mellitus.
Lisa Gill†, Lars Mattison, Arpan Patel, Katherine Jacobs, Paul Iaizzo*.
University of Minnesota, Minneapolis, MN, United States.
INTRODUCTION: Women with gestational diabetes mellitus (GDM)
have a higher likelihood of cesarean delivery, even after controlling
for infant birthweight. Women with GDM also have elevated levels of
adipokines such as leptin, apelin, and visfatin. These adipokines have been
shown to decrease myometrial contractility in vitro, and are also elevated
in obese women, who have been shown to have decreased myometrial
contractility. We hypothesize that myometrial contractility may also be
decreased in women with GDM.
METHODS: After obtaining patient consent in accordance with our
institutional IRB, myometrial tissue samples were obtained at the time of
scheduled cesarean delivery. Subjects included a cohort of women without
gestational diabetes mellitus (GDM), and a cohort of cases who were
diagnosed with GDM. Muscle bundles approximately 20 mm long by 2
mm wide were dissected and suspended under isometric conditions. The
muscle bundles were then submerged in an oxygenated Krebs buffer that
was maintained at 37° C. Plate electrodes stimulated the muscles inducing
contractions. After an initial period of recovery, 1 hour of contraction force
was recorded. Peak contraction force was continually recorded throughout
the experiment, and analyzed directly, and normalized to muscle crosssectional area. Data were compared using a student t test.
RESULTS: The control group (10 subjects) had a mean contraction force
of 8.85±0.77g (n=49 bundles) compared to the diabetic group (5 subjects)
with 10.31±1.49g (n=24 bundles). Analysis of the contraction force
directly showed no significant difference between the two groups. When
normalized by cross-sectional area, the control data had a mean force of
32.11g/mm2 compared to 48.11g/mm2 in diabetics which was statistically
significant (p<0.05), however cross sectional area itself confounds this.
Diabetic myometrium showed significantly more contractions per hour
at a rate of 7.3±0.3 contractions/hour compared to 6.0±0.4 contractions/
hour in the control group (p<0.05).
CONCLUSION: Myometrial contraction force as well as contraction
frequency may be increased in women with GDM when compared to
women without GDM. More study into the mechanism of this difference
is needed.
*Figure(s) will be available online.

T-029
Neurodevelopmental Outcomes after Late Preterm Birth. Cynthia
Gyamfi-Bannerman. for the Eunice Kennedy Shriver National Institute
of Child Health and Human Development Maternal-Fetal Medicine Units
Network, Bethesda, MD, United States.
INTRODUCTION: Retrospective data show an association between late
preterm (LP) birth and adverse cognitive outcomes; but only proxies for
neurodevelopment, such as school performance, are available. We sought
to test the hypothesis that mean intelligence quotient (IQ) scores would
be lower in former LP compared with former full term (FT) children.

Thursday Posters

performance of an MRI sequence (R2*) in women with dysmenorrhea
and healthy controls. The raw R2* value is a standardized measurement
of the T2 relaxation rate with an MRI scanner that allows comparison
between different machines that has been useful for the clinical diagnoses,
but not yet applied to study dysmenorrhea.
METHODS: Healthy controls (n=10) and patients with dysmenorrhea,
confirmed with diary data (n=16) participated on and off their menses in
an IRB approved study. After a series of anatomical pelvic scans using a
3T MRI scanner, a twelve-second breath hold measurement of R2* was
performed to provide an objective calculation of the ratio of oxygenated
to deoxygenated hemoglobin within the uterus. Each participant then
ingested 440 mg of naproxen, and ninety minutes later participants were
rescanned. Two independent blinded reviewers analyzed MRI R2* data
from healthy controls and patients with dysmenorrhea. The correlation
between reviewers and significance of differences were calculated between
groups and time points in STATA.
RESULTS: Signal measurements between observers were highly
correlated (r=0.96). Recruited participants in the dysmenorrhea (Age:
31 ± 3, BMI: 24 ± 2) and healthy cohort (Age: 31 ± 3, BMI: 22 ± 1) had
comparable demographic factors. However, women with dysmenorrhea on
average missed 4 ± 1 days of work/school over the last 90 days. Whereas
menstrual pain was negligible in healthy controls, women with menstrual
pain had an average 0-100 pain score of 77 ± 4 off NSAIDS and 48 ±
4 on NSAIDS. Off menses, healthy controls had an R2* signal of 23 ±
1 comparable to women with dysmenorrhea 21 ± 1. On menses before
naproxen, healthy controls had an elevated R2* signal of 53 ± 5. Women
with dysmenorrhea had significantly less R2* signal (23 ± 1) compared
to healthy controls (p<0.01). After naproxen, there was no difference
between healthy controls (43 ± 4) and women with dysmenorrhea (43 ±
4). Differences in signal were restricted to the myometrium.
CONCLUSION: Consistent results were observed across reviewers
and participant groups/days supporting the use of R2* as an objective
metric of uterine vascular function. Women with dysmenorrhea had
myometrial hemodynamic function differing from healthy controls on
their menses that was reversed with naproxen. The directionality of the
R2* signal suggests that uterus becomes ischemic during menses even
in healthy controls. However, in women with dysmenorrhea, additional
inflammation occurs which is reversed with naproxen. Future utilization
of this objective metric may allow for better phenotyping of menstrual
pain and identification of therapeutic strategies for resolving hemodynamic
dysfunction in refractory patients.

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