(327) Amphiregulin downregulation during preeclampsia may have long lasting cardiovascular effects

There are fundamental knowledge gaps in the molecular mechanisms underlying preeclampsia pathogenesis. Even less is understood on how dysregulated signaling contributes to adverse cardiovascular outcomes postpartum. We hypothesize that macrophages, which regulate vascular function and inflammation play a key role.

Study Design:

Serum (n=80) and fresh full thickness placental biopsies (n=60) were obtained from our institution’s biorepository. Serum was obtained 2 years postpartum (n=40) in individuals with a hypertensive disorder of pregnancy (HDP). Chorionic villi were dissected and used to generate placental conditioned media (CM) as previously described or fixed in formalin. THP-1 macrophages were incubated with CM for 24 hours to generate placental conditioned macrophages (PCM). Cytokine concentration was measured with ELISA. Immunofluorescence and confocal microscopy were used to localize proteins in samples. Clinical variables collected include: HDP diagnosis, blood pressure (BP). Ordinary one-way ANOVA was used to compare serum amphiregulin across HDP severity and diagnoses.

Results:

AREG was the most induced gene in placental conditioned macrophages (Figure 1a). PCM expression of AREG was reduced with HDP. Amphiregulin was present in the serum of HDP patients and strongly correlated strongly with disease severity (p< 0.0001), Figure 1b. These differences persisted 2 years postpartum (p=0.03), Figure 1c, but did not correlate with BP. Amphiregulin was abundant in placental conditioned media; however, levels did not correlate with HDP severity. Macrophage secretion of amphiregulin was not dependent on placental amphiregulin, suggesting an alternative pathway of regulation. Immunofluorescence localized amphiregulin to maternal macrophages on the surface of the syncytiotrophoblast in placental explants (Figure 1d).

Conclusion:

Our data implicate macrophage-dependent regulation of amphiregulin in the development of hypertensive disorders during pregnancy with persistence postpartum. Future studies examining amphiregulin as a predictor of HDP and postpartum endothelial dysfunction are warranted.