269: Association between severe early onset preeclampsia (PE) and serum measures of first trimester pregnancy associated plasma protein A (PAPP-A) and human chorionic gonadotrophin (hCG)

Abstract

STUDY DESIGN: Human placental BP and CV samples were obtained from singleton pregnancies (24-41 weeks gestation). PE samples (n1⁄48) were gestational-age matched to CTL (n1⁄48). Term CTL samples were used for the labor (n1⁄48) and non-labor (n1⁄48) samples. Tissues were dissected, rinsed and frozen after delivery (<60 min). Immunoblot analysis was performed on protein lysates with anti-PAPP-A2 (RD 1:1,000) or anti-b-actin antibody (Sigma; 1:2000) to normalize for protein loading. Densitometry of the immunoreactive bands was performed using Biorad Chemi Doc. Statistical analysis was performed using Prism 5.0 to compare means (t-test) and determine correlations (Pearson). A p-value of <0.05 was considered significant. RESULTS: PAPPA-A2 levels were significantly higher in PE compared to CTL in both the BP (p1⁄40.02) and CV (p1⁄40.003). Evaluation of preterm and term samples separately maintained significant differences for preterm BP (p1⁄40.004), preterm CV (p1⁄40.03) and term CV (p1⁄40.005); but not for term BP (p1⁄4 0.37). PAPP-A2 expression was not affected by labor in the BP (p1⁄4 0.22) or CV (p1⁄4 0.28). PAPP-A2 levels showed strong correlation between BP and CV in CTL labor (r1⁄4 0.89, p1⁄40.003) and non-labor samples (r1⁄4 0.73, p1⁄4 0.04). In contrast, a non-significant weak inverse correlation between BP and CV PAPP-A2 expression was noted for PE samples (r1⁄4 -0.18; p1⁄40.66). CONCLUSION: PAPP-A2 levels in PE are more dysregulated in the CV compared to BP. While PAPP-A2 levels show a strong correlation between BP and CV of CTL placentas, this is not seen in the PE samples also suggesting differential regulation of PAPP-A2 in these regions. Labor does not alter PAPP-A2 expression; thus is not a confounder.