341 - Intraamniotic exposure to the early-onset human preeclamptic placental secretome is associated with altered saccular stage fetal lung architecture

Publication Number: 1325.341

Paulina Horowitz, Boston University School of Medicine, Rockville, MD, United States; Diya Pamidimukkla, Boston University School of Medicine, Boston, MA, United States; Steven Abman, university of colorado, Denver, CO, United States; Elizabeth Taglauer, Boston University School of Medicine, Boston, MA, United States

Background: Mechanisms in which antenatal determinants such as preeclampsia cause placental dysfunction and contribute to high risk for the development of bronchopulmonary dysplasia (BPD) are poorly understood. We recently created an in vitro model to identify primary human placental secreted proteins from early-onset severe preeclamptic pregnancies ( < 32 weeks) that are strongly associated with BPD risk. We hypothesize that altered signaling from human placental tissues during early-onset preeclampsia can impair fetal lung architecture during the saccular stage of lung development.

Objective: Evaluate the impact of the placental secrotome from early onset preeclampsia fetal lung structure during the saccular stage of lung development.

Design/Methods: Human placental tissues were collected at 28-32 weeks gestation from patients with either preeclampsia (PE) or preterm labor (PTL) (Table 1). Placental tissue explants placed into transwell culture for 24 hours to capture secreted proteins in conditioned media (CM) from each patient group (PE-CM and PTL-CM). Following collection, PE-CM or PTL-CM samples (n=3 each) were injected into the intraamniotic compartment of pregnant rats at embryonic day (E)20 (50uL/sac) A control group was also injected with media alone (CTL, n=2). (Fig.1). Neonatal rat lungs were harvested at E22 and distal lung architecture was evaluated by microscopy and with morphometric analysis using determination of mean linear intercept (MLI).

Results: There were no significant differences in pup weight or litter size between experimental groups (CTL, PTL-CM and PE-CM). Analysis of neonatal rat lung architecture revealed increased dilation of distal air sacs in the PE-CM (Fig. 2A). Blinded MLI analysis of lung tissues also revealed a significant increase in the PE-CM exposed group as compared with PTL-CM (p= 0.015, Fig. 2B).

Conclusion(s): We found that intrauterine exposure to the preeclamptic placental secretome during the saccular stage of development impairs distal lung growth as characterized by reduced septation. This work has established a novel pre-clinical model system to evaluate mechanisms underlying the impact of the human preeclamptic placental secretome on fetal lung development. Future studies with larger sample numbers and cell-specific analyses with this model system will deepen our understanding preeclamptic mechanisms driving antenatal BPD risk.

Table 1. Patient Demographics of Human Placental Conditioned Media Samples Preeclampsia vs Preterm Labor


Figure 1. Study Design
Figure 1 PAS Rat Lung PRIME.jpegStudy design illustrating intraamniotic injection of conditioned media from human placental explants collected at 28-32 weeks gestation from pregnant patients with either preterm labor or early-onset preeclampsia. Following injection at embryonic day (E)20, neonatal rat lungs were harvested for histological analysis at E22.

Figure 2. Neonatal Rat Lung Histological Analysis Following Antenatal Intraamniotic Exposure to Preeclamptic vs Preterm Labor Human Placental Conditioned Media
Figure 2-2.jpegA. Representative hematoxylin and eosin stained neonatal rat lung slides at embryonic day (E)22 in experimental groups as described. B. Quantification of mean linear intercept analysis of neonatal lung tissues. CTL: control, media only injection, PTL-CM: intraamniotic injection of human placental conditioned media from preterm labor patients, PE-CM: intraamniotic injection of human placental conditioned media from preeclamptic patients. ** p <0.01. n=7-8 pups per group from 2-3 litters. Different symbols represent pups from different litters.