(984) Effects of lactation and mother-offspring interaction on oxytocin and postpartum cardiovascular health in murine model

Friday, February 10, 2023

3:30 PM – 5:00 PM

Objective: Maternal-offspring separation has adverse effects on maternal cardiovascular health in a murine model. These effects may be mediated by oxytocin (OXT), which is produced in response to both nipple stimulation and maternal-offspring interaction. We sought to quantify the effect of each of these mechanisms on maternal hypothalamic OXT production and post-partum cardiovascular (CV) parameters.

Study Design: Nonpregnant CD1 mice underwent baseline blood pressure (BP) and echocardiogram (ECHO) assessment. Animals then underwent thelectomy (TL, nipples surgically removed) or sham thelectomy (STL). Following pregnancy and delivery, dams were allocated to 3 conditions: 1) TL dams housed with another dam and 8 pups, maternal-pup interaction but no lactation (TL group). 2) STL dams housed with 8 pups, normal lactation (STL group). 3) STL dams separated from pups and housed alone (CTR-STL group). At 1-month post-partum, BP and ECHO were measured and normalized to baseline. OXT in plasma and hypothalamic CD38 were measured using xMAP assay and real-time RT qPCR. Results were analyzed using One-Way and Kruskal-Wallis ANOVA with appropriate post-hoc tests (P < . 05).

Results: Compared with STL dams, OXT levels (Fig1) were significantly lower in TL (P < . 01) and CTR-STL (P=0.018). CD38 gene expression, which regulates OXT, was lower in TL (P < .01) and CTR-STL (P= < . 01). These differences mirrored CV parameters: compared with STL, systolic BP (Fig2) and mean BP was significantly higher in TL (P=.03) and CTR-STL (P=.04) dams, and diastolic BP was higher in CTR-STL (P=.03) dams. Ejection fraction lower in CTR-STL (P=.02) mice. The mitral inflow E wave/tissue Doppler mitral annulus velocity (E/A) ratio was significantly lower in TL (P=.04) and CTR-STL (P=.02).

Conclusion: Compared with normal lactation, both thelectomy and complete separation were associated with reduced OXT and deleterious CV parameters at 1 month postpartum. These results suggest that disruption of lactation, not mother-offspring interaction, mediates the effects of mother-offspring separation on CV health.

Coauthor(s)

TP
Tia Pearcy, BS
UTHSCSA
San Antonio, Texas, United States
SP
Sureshkumar Pillai, PhD
University of Texas Health San Antonio
San Antonio, Texas, United States
LD
Logan Davis, BS
UT Health San Antonio
San Antonio, Texas, United States
KK
Kaitlin D. Kersh, BS
UT Health San Antonio
San Antonio, Texas, United States
AA
Ashlie-Chellsie Aminkeng, N/A
UT Health San Antonio
San Antonio, Texas, United States
GA
Gregory Aune, MD, PhD
UT Health San Antonio
San Antonio, Texas, United States
Alison M. Stuebe, MD, MSc (she/her/hers)
Professor of Obstetrics and Gynecology
University of North Carolina
Chapel Hill, North Carolina, United States

Primary & Presenting Author(s)

Egle Bytautiene Prewit, MD, PhD (she/her/hers)
UT Health San Antonio
San Antonio, Texas, United States