765: Human placental expression of the hydrogen sulfide synthesizing system: effects of gestational age and preeclampsia

765 Human placental expression of the hydrogen sulfide synthesizing system: effects of gestational age and preeclampsia Jennifer Hodges, Wen Wang, Thomas Lechuga, Louise Laurent, Mana Parast, Dong-bao Chen University of California Irvine, Obstetrics and Gynecology, Irvine, CA, University of California, San Diego Medical Center, Reproductive Medicine, San Diego, CA, University of California San Diego, Department of Pathology, San Diego, CA, Univeristy of California Irvine, Obstetrics and Gynecology, Irvine, CA OBJECTIVE: Hydrogen sulfide (H2S) is emerging as a novel gasotransmitter that regulates angiogenesis and vasodilatation under physiologic and ischemic conditions. H2S is synthesized primarily by cystathionine -lyase (CSE) and cystathionine -synthase (CBS). Preeclampsia is characterized by dysfunctional endothelium and impaired angiogenesis. The hypotheses of this study are that H2S-synthesizing enzymes are developmentally regulated in normal human trophoblasts and that preeclampsia affects their expression and H2S production in human placenta. STUDY DESIGN: Placentas from first (8-12 wk) and second (12-18 wk) trimester (n 6/group) pregnancies were collected from elective terminations. Placental samples from healthy term (n 5) and severe preeclamptic (n 7) patients were collected after delivery. Placental villous tissues were washed in phosphate-buffered saline and either snap-frozen and stored in liquid nitrogen or fixed in 4% paraformaldehyde. CSE and CBS mRNA and protein expressions were examined by real-time PCR and Western blot. Their cellular localization was determined by immunofluorescence microscopy on paraffin-embedded sections. Methylene blue assay was used to quantify H2S production. RESULTS: Both CBS and CSE mRNAs were detected in human placentas. CBS mRNA did not change (p 0.05) according to gestational age while CSE mRNA was increased at term compared to first trimester. Both CSE and CBS proteins co-localized with cytokeratin-7 in the syncytiotrophoblasts lining the placental villi and increased according to gestational age. Expression of both proteins was low in the CD31positive placental endothelial cells. Compared to controls, both CSE and CBS proteins were significantly increased in preeclamptic placentas. H2S production in the preeclamptic placentas was 1.2-fold higher to that in the controls (p 0.07). CONCLUSION: The H2S-synthesizing system is regulated in human placenta according to gestational age and by preeclampsia. These results implicate that H2S might play a role in placental physiology and the pathophysiology of preeclampsia (Supported by NIH grants). 766 Dysfunctional vascular adaptations in human umbilical vein endothelial cells (HUVEC) in preeclamptic pregnancies Jennifer Krupp, Derek Boeldt, Fu-Xian Yi, Ian Bird, Dinesh Shah University of WI School of Medicine and Public Health, Obstetrics and Gynecology, Maternal Fetal Medicine, Madison, WI, University of WI School of Medicine and Public Health, Obstetrics and Gynecology, Madison, WI, University of WI School of Medicine and Public Health, Obstetrics and Gynecology & Pediatrics, Madison, WI OBJECTIVE: Preeclampsia (PE) occurs in 4-8% of all pregnancies. Endothelial cell dysfunction due to PE seen on the maternal side is also found in the umbilical vein. Our previous studies on umbilical vein endothelium (UV endo) of fresh cord vessels showed the sustained nitric oxide production and initial and sustained Ca2 burst responses of normal pregnancy are impaired in PE. The basis of this dysfunction is unclear. Our hypothesis is these losses in Ca2 response may either be due to failed programming of cell function or active suppression of such programming by local factors or inflammatory mediators. Removal of UV endo from the vessels and maintenance in vitro could indicate if recovery of function of HUVECs is possible, so suggesting that endothelial recovery on the maternal side at least may be possible given suitable therapy. STUDY DESIGN: HUVEC isolated from normal (N 7) and PE (N 6) subjects maintained in culture in vitro to passage 3 were imaged using Fura-2 to detect Ca2 responses to stimulation with ATP (100um). Area under the curve (AUC), total number of bursts and mean Ca2 response for the sustained phase were quantified. RESULTS: HUVEC from PE subjects do recover function (Figure) but with an increased frequency of Ca2 bursts (* p 0.05) relative to control. There is no significant difference in the AUC between the normal and PE HUVEC. Despite the increased Ca2 burst frequency in PE HUVEC, peak height is reduced and the overall AUC is not increased. CONCLUSION: While intact PE UV endo lack sustained Ca2 bursts in vivo, PE derived HUVEC maintained in vitro do show both restored Ca2 bursting and increased frequency relative to control. Any such recovery of function in vitro suggests there was indeed a suppression of function by local factors in vivo. Further, since PE derived HUVEC manifest sustained Ca2 burst responses which are both more rapid and of reduced size relative to control HUVEC, this suggests cell signaling programming is also altered relative to control. Funded by NIH Grant R21HD069181. Poster Session V Academic Issues, Antepartum Fetal Assessment, Genetics, Hypertension, Medical-Surgical-Disease www.AJOG.org