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Gastric emptying in human fetus: when does it start?
SMFM Abstracts S189
Volume 189, Number 6 Am J Obstet Gynecol 471
UMBILICAL BLOOD OXIDATIVE SRESS: ARTERIOVENOUS DIFFERENCE OFER FAINARU1, ITAY FOGEL1, ILYA PINCHUK2, BENY ALMOG1, RONNI GAMZU1, DOV LICHTENBERG2, JOSEPH B LESSING1, MICHAEL KUPFERMINC1, 1Tel Aviv University, Obstetrics and Gynecology, Tel Aviv, Israel 2Tel Aviv University, Physiolgy and Pharmacology, Tel Aviv, Israel OBJECTIVE: Oxidative stress, due to an imbalance between prooxidants and antioxidants, has been shown to aggravate a variety of neonatal pathological states. We tested whether neonates are subject to oxidative stress, by comparing lipid oxidative parameters of umbilical arterial- and venous blood. STUDY DESIGN: Our study groups consisted of 32 pregnant women who delivered by elective cesarean section (CS), and of 32 age- and gestational age matched pregnant women who delivered by spontaneous vaginal delivery (SVD). Arterial- and venous blood were drawn from the umbilcal cords and serum was prepared and frozen immediately at 708. Copper-induced oxidation of serum samples was monitored spectroscopically by continuous recording of absorbance at 245 nm. The time dependent increase of absorbance at 245 nm is caused by the formation of conjugated dienic hydroperoxides and 7-ketocholesterol during lipid peroxidation. The lag preceding oxidation reflects the resistance of serum lipids to oxidative stress. RESULTS: The lag preceding copper induced oxidation was significantly shorter in umbilical arteries when compared to umbilical veins irrespective of mode of delivery (14.0 ± 1.8 vs. 50.6 ± 8.25 min, p = 0.0004 in SVD group; 17.7 ± 1.6 vs. 39.2 ± 7.6 min, p = 0.006 in CS group). Concentrations of total cholesterol, triglycerides, HDL and LDL in arterial- and venous serum were similar in both of these vessels irrespective of mode of delivery. Arterial blood gasses exhibited lower pH values, and lower base excess values when compared to the respective venous values in both modes of delivery. CONCLUSION: The lag preceding oxidation of umbilical arterial serum lipids is shorter when compared to umbilical venous blood, indicating high oxidative stress in the fetal circulation irrespective of mode of delivery. This may be due to lack of antioxidants and/or high generation of prooxidants by the fetus.These possibilities and the plausible role for antioxidant supplementation during pregnancy warrant further studies.
473
EXPRESSION OF CALCITONIN GENE-RELATED PEPTIDE BY HUMAN PLACENTAL VILLI AND ITS REGULATION BY STEROID HORMONES YUAN-LIN DONG1, MADHU CHAUHAN1, PASSARA LANLUA1, HUI-QUN WANG2, GARY HANKINS1, LINDA GOODRUM1, ELIZABETH MARTIN1, CHANDRA YALLAMPALLI1, 1University of Texas Medical Branch, Obstetrics & Gynecology, Galveston, TX 2University of Texas Medical Branch, Pathology, Galveston, TX OBJECTIVE: Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide. Recently, we obtained evidence that CGRP receptors were expressed in human trophoblasts and placental vessels, suggesting the involvement of CGRP in the control of placental functions. However, the source of CGRP in fetomaternal interface remains unknown. Our objective was to investigate whether human placenta was a source of CGRP production, and if so, whether CGRP secretion was regulated by steroid hormones. STUDY DESIGN: Human placentas were obtained from spontaneous deliveries at 38-40 weeks of pregnancy. In situ hybridization of CGRP mRNA expression in villous tissues and fetal membranes were carried out to determine their cellular localization. Total RNA was extracted from tissues and changes in CGRP mRNA expression was determined by RT-PCR. The secretion of CGRP by cultured villous tissues was determined by CGRP radioimmunoassay. RESULTS: 1) in situ hybridization analysis revealed that CGRP mRNA was abundantly expressed in cytotrophoblasts, but not in syncytiotrophoblasts, of the placental villous tissues. CGRP mRNA was also expressed in epithelial cells of the amniotic membrane and in trophoblast layer of the chorionic membrane; 2) the expression of CGRP mRNA was most abundant in villous tissues and least in amniotic membranes; 3) CGRP mRNA in villous tissues was significantly increased by progesterone (209% vs. 100% in control; p < 0.01), but not by 17bestradiol, and 4) immunoreactive CGRP secreted by cultured villi was also significantly increased by progesterone (195% vs. 100% in control; p < 0.01), but not by 17b-estradiol. CONCLUSION: These findings revealed that mRNA for CGRP is expressed and CGRP protein is synthesized by trophoblasts and epithelial cells in human placental tissues. This is the first report showing that CGRP may act as an autocrine/paracrine factor in the control of placental functions during pregnancy.
472
GASTRIC EMPTYING IN HUMAN FETUS: WHEN DOES IT START? MASAKATSU SASE1, MASAHIKO NAKATA1, NORIHIRO SUGINO1, 1Yamaguchi Univ., Ob/Gyn, Ube, Yamaguchi, Japan OBJECTIVE: Fetal swallowing and gastric emptying contribute to amniotic fluid volume (AFV) homeostasis and fetal gastrointestinal development. As fetal urine contributes to AFV by the end of the first trimester, we speculated that fetal swallowing and gastric emptying must be functional to prevent rapid increases in AFV. We sought to determine the gestation for initiation of gastric emptying in the human fetus. STUDY DESIGN: Gastric emptying of eighty normal human fetuses at 12 to 39 weeks of gestation was studied. Real-time ultrasound of the fetal stomach (defined as the largest gastric area inclusive of the pylorus) was continuously recorded for a minimum of 1 hour (60 to 112 min). Images were replayed with measurements of gastric size every minute. The change in gastric area was defined as a change between the maximum and the minimum gastric area divided by the maximum gastric area. Gastric emptying was defined as a 50% change in gastric area, based upon the 10th percentile of the percent change in gastric area observed in fetuses at 36-39 weeks gestation. RESULTS: Fetal gastric emptying was detected as early as 12 5/7 weeks gestation. The proportion of fetuses with evidence of gastric emptying increased in relation to gestational age, beginning at 28 weeks of gestation. The rates of gastric emptying did not change from 12-19 weeks (25%; 5/20) to 20-27 weeks (24%; 5/21), but significantly increased at 28-31 weeks (82%; 9/11) with a further increase to 93% (25/27) at 32-39 weeks. CONCLUSION: Fetal gastric emptying occurs by the beginning of the second trimester, contributing to AFV regulation. The increased evidence of gastric emptying in late gestation is likely secondary to increased swallowing, altered fetal behavioral state and/or endogenous production of gastrointestinal motility factors.
474
ADRENOMEDULLIN ENHANCES TROPHOBLAST INVASIVE POTENCY ASSOCIATED WITH INCREASED MATRIX METALLOPROTEINASE ACTIVITY XIAOQUAN ZHANG1, KORTNEY GREEN1, MADHU CHAUHAN1, CHANDRA YALLAMPALLI1, YUAN-LIN DONG1, 1University of Texas Medical Branch, Obstetrics & Gynecology, Galveston, TX OBJECTIVE: Trophoblast invasion is precisely regulated, being confined spatially to the myometrium and temporally to early pregnancy. Defective invasion of the trophoblast is thought to be involved in the preeclampsia, a major and frequent complication of human pregnancy; however, mechanisms regulating trophoblast invasion remain elusive. The objective of this study is to investigate the role of adrenomedullin (AM), a multifunctional peptide, in the human trophoblast invasion process, and the mechanism mediating AM actions. STUDY DESIGN: Human trophoblast cell line JAr cells was cultured in RPMI 1640 with or without AM. The expression of mRNA for AM and its receptor components calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein 2 (RAMP2) were examined by RT-PCR. The presence and distribution of AM receptor were evaluated by immunofluorescent staining with specific antibodies.The activity of matrix metalloproteinase (MMP-9) was assayed using substrate gel zymography, and the trophoblast invasion was quantified with matrigel-coated transwell inserts containing polycarbonate filters. RESULTS: 1) mRNA for AM and its receptor components CRLR/RAMP2 were abundantly expressed by JAr cells; 2) immunofluorescent staining showed that CRLR and RAMP2 proteins were shown on the cell membrane and cytosol; 3) the presence of MMP-9 in the trophoblast culture medium was detected by gelatinase zymography. Treatment of trophoblasts with AM (0.01 lM) increased the proteinase activity of MMP-9; 4) Matrigel assay showed both the number of trophoblast passing through the membrane, and the invasive index were significantly increased by AM (0.01 lM), and the invasion-promoting action of AM was blocked by AM antagonist AM22-52 (0.1 lM). CONCLUSION: Our collective data demonstrate that AM and its receptors are expressed in human trophoblast and constitute a potential autocrine mechanism that could drive trophoblast invasion by modulating the activity of MMP-9.
Volume 189, Number 6 Am J Obstet Gynecol 471
UMBILICAL BLOOD OXIDATIVE SRESS: ARTERIOVENOUS DIFFERENCE OFER FAINARU1, ITAY FOGEL1, ILYA PINCHUK2, BENY ALMOG1, RONNI GAMZU1, DOV LICHTENBERG2, JOSEPH B LESSING1, MICHAEL KUPFERMINC1, 1Tel Aviv University, Obstetrics and Gynecology, Tel Aviv, Israel 2Tel Aviv University, Physiolgy and Pharmacology, Tel Aviv, Israel OBJECTIVE: Oxidative stress, due to an imbalance between prooxidants and antioxidants, has been shown to aggravate a variety of neonatal pathological states. We tested whether neonates are subject to oxidative stress, by comparing lipid oxidative parameters of umbilical arterial- and venous blood. STUDY DESIGN: Our study groups consisted of 32 pregnant women who delivered by elective cesarean section (CS), and of 32 age- and gestational age matched pregnant women who delivered by spontaneous vaginal delivery (SVD). Arterial- and venous blood were drawn from the umbilcal cords and serum was prepared and frozen immediately at 708. Copper-induced oxidation of serum samples was monitored spectroscopically by continuous recording of absorbance at 245 nm. The time dependent increase of absorbance at 245 nm is caused by the formation of conjugated dienic hydroperoxides and 7-ketocholesterol during lipid peroxidation. The lag preceding oxidation reflects the resistance of serum lipids to oxidative stress. RESULTS: The lag preceding copper induced oxidation was significantly shorter in umbilical arteries when compared to umbilical veins irrespective of mode of delivery (14.0 ± 1.8 vs. 50.6 ± 8.25 min, p = 0.0004 in SVD group; 17.7 ± 1.6 vs. 39.2 ± 7.6 min, p = 0.006 in CS group). Concentrations of total cholesterol, triglycerides, HDL and LDL in arterial- and venous serum were similar in both of these vessels irrespective of mode of delivery. Arterial blood gasses exhibited lower pH values, and lower base excess values when compared to the respective venous values in both modes of delivery. CONCLUSION: The lag preceding oxidation of umbilical arterial serum lipids is shorter when compared to umbilical venous blood, indicating high oxidative stress in the fetal circulation irrespective of mode of delivery. This may be due to lack of antioxidants and/or high generation of prooxidants by the fetus.These possibilities and the plausible role for antioxidant supplementation during pregnancy warrant further studies.
473
EXPRESSION OF CALCITONIN GENE-RELATED PEPTIDE BY HUMAN PLACENTAL VILLI AND ITS REGULATION BY STEROID HORMONES YUAN-LIN DONG1, MADHU CHAUHAN1, PASSARA LANLUA1, HUI-QUN WANG2, GARY HANKINS1, LINDA GOODRUM1, ELIZABETH MARTIN1, CHANDRA YALLAMPALLI1, 1University of Texas Medical Branch, Obstetrics & Gynecology, Galveston, TX 2University of Texas Medical Branch, Pathology, Galveston, TX OBJECTIVE: Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide. Recently, we obtained evidence that CGRP receptors were expressed in human trophoblasts and placental vessels, suggesting the involvement of CGRP in the control of placental functions. However, the source of CGRP in fetomaternal interface remains unknown. Our objective was to investigate whether human placenta was a source of CGRP production, and if so, whether CGRP secretion was regulated by steroid hormones. STUDY DESIGN: Human placentas were obtained from spontaneous deliveries at 38-40 weeks of pregnancy. In situ hybridization of CGRP mRNA expression in villous tissues and fetal membranes were carried out to determine their cellular localization. Total RNA was extracted from tissues and changes in CGRP mRNA expression was determined by RT-PCR. The secretion of CGRP by cultured villous tissues was determined by CGRP radioimmunoassay. RESULTS: 1) in situ hybridization analysis revealed that CGRP mRNA was abundantly expressed in cytotrophoblasts, but not in syncytiotrophoblasts, of the placental villous tissues. CGRP mRNA was also expressed in epithelial cells of the amniotic membrane and in trophoblast layer of the chorionic membrane; 2) the expression of CGRP mRNA was most abundant in villous tissues and least in amniotic membranes; 3) CGRP mRNA in villous tissues was significantly increased by progesterone (209% vs. 100% in control; p < 0.01), but not by 17bestradiol, and 4) immunoreactive CGRP secreted by cultured villi was also significantly increased by progesterone (195% vs. 100% in control; p < 0.01), but not by 17b-estradiol. CONCLUSION: These findings revealed that mRNA for CGRP is expressed and CGRP protein is synthesized by trophoblasts and epithelial cells in human placental tissues. This is the first report showing that CGRP may act as an autocrine/paracrine factor in the control of placental functions during pregnancy.
472
GASTRIC EMPTYING IN HUMAN FETUS: WHEN DOES IT START? MASAKATSU SASE1, MASAHIKO NAKATA1, NORIHIRO SUGINO1, 1Yamaguchi Univ., Ob/Gyn, Ube, Yamaguchi, Japan OBJECTIVE: Fetal swallowing and gastric emptying contribute to amniotic fluid volume (AFV) homeostasis and fetal gastrointestinal development. As fetal urine contributes to AFV by the end of the first trimester, we speculated that fetal swallowing and gastric emptying must be functional to prevent rapid increases in AFV. We sought to determine the gestation for initiation of gastric emptying in the human fetus. STUDY DESIGN: Gastric emptying of eighty normal human fetuses at 12 to 39 weeks of gestation was studied. Real-time ultrasound of the fetal stomach (defined as the largest gastric area inclusive of the pylorus) was continuously recorded for a minimum of 1 hour (60 to 112 min). Images were replayed with measurements of gastric size every minute. The change in gastric area was defined as a change between the maximum and the minimum gastric area divided by the maximum gastric area. Gastric emptying was defined as a 50% change in gastric area, based upon the 10th percentile of the percent change in gastric area observed in fetuses at 36-39 weeks gestation. RESULTS: Fetal gastric emptying was detected as early as 12 5/7 weeks gestation. The proportion of fetuses with evidence of gastric emptying increased in relation to gestational age, beginning at 28 weeks of gestation. The rates of gastric emptying did not change from 12-19 weeks (25%; 5/20) to 20-27 weeks (24%; 5/21), but significantly increased at 28-31 weeks (82%; 9/11) with a further increase to 93% (25/27) at 32-39 weeks. CONCLUSION: Fetal gastric emptying occurs by the beginning of the second trimester, contributing to AFV regulation. The increased evidence of gastric emptying in late gestation is likely secondary to increased swallowing, altered fetal behavioral state and/or endogenous production of gastrointestinal motility factors.
474
ADRENOMEDULLIN ENHANCES TROPHOBLAST INVASIVE POTENCY ASSOCIATED WITH INCREASED MATRIX METALLOPROTEINASE ACTIVITY XIAOQUAN ZHANG1, KORTNEY GREEN1, MADHU CHAUHAN1, CHANDRA YALLAMPALLI1, YUAN-LIN DONG1, 1University of Texas Medical Branch, Obstetrics & Gynecology, Galveston, TX OBJECTIVE: Trophoblast invasion is precisely regulated, being confined spatially to the myometrium and temporally to early pregnancy. Defective invasion of the trophoblast is thought to be involved in the preeclampsia, a major and frequent complication of human pregnancy; however, mechanisms regulating trophoblast invasion remain elusive. The objective of this study is to investigate the role of adrenomedullin (AM), a multifunctional peptide, in the human trophoblast invasion process, and the mechanism mediating AM actions. STUDY DESIGN: Human trophoblast cell line JAr cells was cultured in RPMI 1640 with or without AM. The expression of mRNA for AM and its receptor components calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein 2 (RAMP2) were examined by RT-PCR. The presence and distribution of AM receptor were evaluated by immunofluorescent staining with specific antibodies.The activity of matrix metalloproteinase (MMP-9) was assayed using substrate gel zymography, and the trophoblast invasion was quantified with matrigel-coated transwell inserts containing polycarbonate filters. RESULTS: 1) mRNA for AM and its receptor components CRLR/RAMP2 were abundantly expressed by JAr cells; 2) immunofluorescent staining showed that CRLR and RAMP2 proteins were shown on the cell membrane and cytosol; 3) the presence of MMP-9 in the trophoblast culture medium was detected by gelatinase zymography. Treatment of trophoblasts with AM (0.01 lM) increased the proteinase activity of MMP-9; 4) Matrigel assay showed both the number of trophoblast passing through the membrane, and the invasive index were significantly increased by AM (0.01 lM), and the invasion-promoting action of AM was blocked by AM antagonist AM22-52 (0.1 lM). CONCLUSION: Our collective data demonstrate that AM and its receptors are expressed in human trophoblast and constitute a potential autocrine mechanism that could drive trophoblast invasion by modulating the activity of MMP-9.