Adrenomedullin in mammalian embryogenesis (original) (raw)
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European Journal of Endocrinology, 2000
Adrenomedullin (AM) is a novel vasorelaxant peptide, isolated from human pheochromocytoma. Although AM may be involved in the regulation of the cardiovascular system, a number of other mechanisms are also involved. The present study was undertaken to confirm the presence of AM in human maternal circulation and in placental function during pregnancy. Immunoreactive (ir) AM concentrations in maternal plasma were 3.4 Ϯ 0.7 fmol/ml (mean Ϯ S.E.M.) in the first trimester, 3.3 Ϯ 1.1 fmol/ml in the second trimester, 7.3 Ϯ 2.8 fmol/ml in the third trimester, 4.1 Ϯ 1.9 fmol/ ml in early puerperium and 3.0 Ϯ 0.4 fmol/ml in non-pregnant periods; the concentration in the third trimester was significantly greater than those in other periods. Plasma concentrations of estradiol (E 2 ), progesterone, human placental lactogen (hPL) and human chorionic gonadotropin (hCG) were also measured, using RIA kits. Significant correlations have been demonstrated between the concentrations of irAM and those of E 2 , progesterone and hPL. We therefore examined the expression of AM within the placental tissues using immunohistochemistry and northern blot analysis in order to demonstrate a correlation between the presence of AM in the placenta and maternal plasma. Using immunohistochemistry, we detected AM in the amnion at term and the expression of AM mRNA in human placental tissues using cloned human (h) AM complementary DNA as a probe. This study demonstrates the immunoreactivity of human hAM in maternal plasma during pregnancy, and suggests that hAM in maternal plasma is generated partly from placental tissue.
Vascular expression of adrenomedullin is increased in Wistar rats during early pregnancy
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2005
Objective: Circulating levels of adrenomedullin (ADM)-a vasodilator peptide with long-lasting effects-increase in the course of pregnancy. Neither the site nor the concomitant rate of ADM synthesis in pregnancy is known. The aim of this study was to test the hypothesis that the rise in plasma levels of ADM during pregnancy is paralleled by increased gene expression and protein levels in the vascular bed. Study design: We determined in cardiovascular and reproductive tissues of non-pregnant (n = 10) and 10-days pregnant (n = 10) Wistar rats ADM gene expression by semi-quantitative RT-PCR (normalized to GAPDH). As a support for the mRNA data, protein concentrations were measured by both ELISA and Western blot analysis. Finally, ADM in these tissues was localized by immunohistochemical staining. Statistical analysis was carried out by applying Mann-Whitney U-test. Results: ADM mRNA levels in the abdominal aorta, renal artery and the kidney were increased during pregnancy. In addition, immunohistochemical staining in the kidney, uterus, abdominal aorta, renal, uterine and superior mesenteric artery was more intense as compared to non-pregnant rats. However, we observed lower concentrations of tissue ADM protein in pregnant rats, indicating an increased release of the hormone by the producing cells. Conclusion: Vascular ADM gene expression is increased in the first half of rat pregnancy. This coincides and may be functionally related to the institution of a high flow/low resistance circulation in pregnancy. #
Biology of Reproduction, 2004
Adrenomedullin (AM), a potent vasorelaxant peptide, has been shown to function as an angiogenic and growth factor. The present study investigated whether antagonism of endogenous AM in rats during early gestation results in diminished placental and fetal growth and whether this occurs through induction of apoptosis. Rats on Gestational Day 8 were implanted s.c. with osmotic minipumps delivering 125 and 250 g rat ؊1 day ؊1 of AM 22-52 and were killed on Gestational Day 15. In AM 22-52-treated rats, both placental and fetal weights were dose-dependently inhibited, with 50% reduction in the group receiving 250 g rat ؊1 day ؊1. In these animals, fetal resorption sites were also increased. Apoptosis was demonstrated in placenta and uterus by the TUNEL method. Apoptotic changes were more apparent in trophoblast cells in the labyrinth zone of placenta and uterine decidua of AM 22-52-treated rats when compared with vehiclecontrol rats. Immunoreactivity to active caspase-3 protein was abundant in the placenta and uterus of the AM 22-52-treated group. Western blot analysis demonstrated that in homogenates of both the placenta and uterus of AM 22-52-treated rats, levels of active caspase-9 and-3 as well as of Poly ADP ribose polymerase were significantly increased, whereas levels of Bcl-2 protein decreased, compared with controls. However, no significant treatment-associated changes were observed in Bid, Fas, Fas ligand, p53, and caspase-8 and-10 proteins in either placenta or uterus. Bad protein was undetectable in either tissue. In mitochondrial fractions from both placenta and uterus, the levels of Bax increased with decreases in cytochrome c on AM 22-52 treatment. Conversely, in the cytosol, Bax levels decreased with increases in cytochrome c, demonstrating translocation of Bax from cytosol to mitochondria and release of cytochrome c from mitochondria with AM 22-52 treatment. In conclusion, these findings show that antagonism of AM in rats during early pregnancy caused fetoplacental growth restriction through the activation of mitochondrial apoptotic pathways.
Adrenomedullin in perinatal medicine
Regulatory Peptides, 2003
This review will consider whether adrenomedullin (AM) plays a role in the different aspects of perinatal medicine: contributing to maternal systemic vasodilatation during pregnancy, regulating uterine and placental blood flow, being involved in the process of implantation and participating in uterine quiescence prior to parturition. In addition, this will also consider whether a modification of AM secretion contributes to some pathological conditions in pregnancy such as preeclampsia and impairment of fetal growth. The biosynthesis of AM increases in gravid rats and in pregnant women, and the placenta represents an important site of AM production during pregnancy. Both the peptide and its receptors have been found in the uterus, placenta, fetal membranes and cord vessels, and fetal membranes and placental tissues in culture secrete AM. AM contributes to maternal systemic vasodilatation, the placental vessels are relaxed by AM in a dose-dependent manner and AM is expressed in the fetoplacental and umbilical vascular endothelium where basal production of AM contributes to low fetoplacental vascular resistances. Controversy exists over the status of circulating and placental AM in preeclampsia and of the relative contribution of AM to impaired fetoplacental circulation and fetal growth. Moreover, the uterus expresses AM mRNA and exogenous AM relaxes the myometrium in a dose-dependent manner; however, clinical studies have shown that AM does not decrease before the onset of parturition. Rather, AM secretion increases during spontaneous labor and in preterm delivery.
Detection of adrenomedullin, a hypotensive peptide, in amniotic fluid and fetal membranes
American Journal of Obstetrics and Gynecology, 1996
OBJECTIVE: Our purpose was to determine whether adrenomedullin, a multifunctional regulatory peptide involved in blood flow regulation and growth stimulation and with antimicrobiai activity, was a component of amniotic fluid from second-trimester human fetus and to determine the source of this peptide. STUDY DESIGN: A prospective descriptive study was performed on 134 patients undergoing amniocentesis after genetic counseling, ultrasonography, and infomed consent. Adrenomedullin expression was determined by immunocytochemical analysis, Western blot analysis, reverse transcriptase-polymerase chain reaction, and in situ reverse transcriptase-polymerase chain reaction in fetal membranes and with radioimmunoassay in amniotic fluid. RESULTS: Radioimmunoassay of the 134 amniotic fluid specimens revealed adrenomedullin-like immunoreactivJty in all of them, ranging in concentration from 10 to 300 fmol/25 gl (170 _+ 62 fmol/25 gl). Immunocytochemical analysis, Western blot analysis, reverse transcriptase-polymerase chain reaction, and in situ reverse transcriptase-polymerase chain reaction further established the expression of adrenomedullin protein and messenger ribonucleic acid in fetal amniotic membranes, suggesting that this organ is the source of amniotic adrenomedullin. CONCLUSIONS; Our results clearly demonstrate the presence of adrenomedullin in second-trimester human amniotic fluid and adrenomedullin messenger ribonucleic acid and protein in amniotic membranes, suggesting that adrenomedullin is a hormone involved in the maintenance of normal pregnancy. Further studies with these molecular tools are in progress to determine the precise role of this hormone and whether adrenomedullin plays a role in the pathogenesis of various disorders of pregnancy. (Am J Obstet Gynecol 1996;175:906-11 .)
Clinical Science, 2006
The aim of the present study was to investigate whether placental and fetal membrane AdM (adrenomedullin) mRNA expression changes with gestation and human labour, as we have previously found labour-associated changes in AdM content in fetal membranes [Al-Ghafra, Gude, Brennecke and King (2003) Clin. Sci. 105, 419–423]. Placentas and fetal membranes were collected either at term or pre-term from women either in-labour or not-in-labour, and AdM mRNA abundance was measured in tissue extracts by Northern blot analysis. Increases were found in the relative abundance of amniotic tissue AdM mRNA in both in-labour and not-in-labour groups at term compared with those at pre-term, and there were positive correlations with gestational age. Relative abundance of choriodecidual tissue AdM mRNA was also significantly elevated in the not-in-labour groups between pre-term and term tissues, although there was no significant correlation with gestational age. However, placental AdM mRNA expression was...
Endocrinology, 1997
For clarifying a process of de-differentiation in culturing chondrocytes, the present study was undertaken to investigate the secretion of adrenomedullin (AM) by chondrocyte phenotype cells and whether or not AM effects this proliferation in a cAMPdependent fashion. Chondrocyte phenotype cells expressed AM and the AM receptor, and secreted high concentration of AM into the culture medium. When added to cultures, AM increased the intracellular cAMP level and decreased the number of these cells in a similar concentration-dependent fashion. Addition of forskolin and dibutyryl-cAMP caused a significant decrease in the number of these cells. Furthermore, the effect of AM was inhibited by a cAMP-dependent protein kinase A inhibitor (H89). The present findings indicate that AM has an autocrine/paracrine type of anti-proliferative effect on these cells mediated via a cAMP-dependent pathway and raise the possibility that AM plays a role in the local modulation of a process of de-differentiation by culturing chondrocyte phenotype cells.
Adrenomedullin expression during hypoxia in fetal sheep
Acta Physiologica Scandinavica, 2005
We asked how adrenomedullin (AM), a vasodilator peptide, was distributed in fetal sheep organs and whether expression of AM would be upregulated in response to moderate acute fetal hypoxia in vivo. Methods: In four sheep at day 126-130 of gestation, nitrogen was added to the inspired air by tracheal infusion to reduce fetal arterial oxygen content for a period of 4 h. Control fetuses were from four ewes given a tracheal infusion of room air. Fetal and maternal blood samples were taken prior to and during hypoxia/sham hypoxia. Fetal tissue samples were frozen for RNA analysis and fixed for immunohistochemistry. Results: In hypoxic fetuses, arterial oxygen content was significantly reduced to 50% compared with sham fetuses with no change in arterial pH in either group. Plasma ACTH levels rose significantly at 2 and 4 h in hypoxic fetuses only. Initial plasma concentrations of AM in control and hypoxic fetuses were 457 AE 20 and 430 AE 35 pg mL)1 and did not change during the experiment. The relative abundance of AM mRNA was placental cotyledons) lung > cerebral cortex @ renal cortex > left ventricle @ right ventricle > adrenal gland > renal medulla > aorta @ liver. Immunohistochemical staining for AM confirmed distinct labelling in organs with significant expression. AM mRNA level increased significantly in cerebral cortex of hypoxic fetuses. Conclusion: Our results show expression of AM in placenta and in several fetal organs in late gestation sheep. AM may participate in the cerebral vasodilatation that is an integral part of the fetal response to hypoxia.
American Journal of Obstetrics and Gynecology, 2000
To examine whether adrenomedullin, a novel vasoactive peptide produced by the placenta, participates in the uteroplacental hemodynamic alterations in intrauterine growth restriction, we studied the correlation between adrenomedullin levels and fetoplacental blood flow. STUDY DESIGN: Maternal and umbilical blood samples were collected in pregnancies complicated by intrauterine growth restriction with abnormal umbilical artery Doppler findings and in control pregnancies. Adrenomedullin levels were measured by means of a specific radioimmunoassay, and flow velocimetry waveforms were recorded from uterine, umbilical, and fetal middle cerebral arteries. RESULTS: Mean adrenomedullin values in umbilical plasma were higher (P < .05) in patients with intrauterine growth restriction (63.7 ± 34.2 pg/mL; n = 16) than in control subjects (38.1 ± 14.8 pg/mL; n = 16). A significant correlation was found between maternal adrenomedullin levels and umbilical artery pulsatility index. Moreover, fetal adrenomedullin concentrations correlated negatively with middle cerebral artery pulsatility index and positively with umbilical artery pulsatility index/middle cerebral artery pulsatility index ratio. CONCLUSION: This study provides evidence that adrenomedullin is increased in fetuses with intrauterine growth restriction in response to reduced uteroplacental blood flow and suggests that it may participate in the fetal hemodynamic modifications.
Role of adrenomedullin2/ intermedin in pregnancy induced vascular and metabolic adaptation in mice
Frontiers in Physiology
Introduction: Adrenomedullin2 (AM2) shares its receptor with Calcitonin gene related peptide and adrenomedullin with overlapping but distinct biological functions. Goal of this study was to assess the specific role of Adrenomedullin2 (AM2) in pregnancy induced vascular and metabolic adaptation using AM2 knockout mice (AM2−/−).Method: The AM2−/− mice were successfully generated using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Nuclease Cas nine system. Phenotype of pregnant AM2−/− mice was assessed with respect to its fertility, blood pressure regulation, vascular health and metabolic adaptations and compared to the wild type littermates (AM2+/+).Results: Current data shows that AM2−/− females are fertile with no significant difference in number of pups/litter compared to the AM2+/+. However, ablation of AM2 decreases the gestational length and the total number of pups born dead or that die after birth is greater in AM2−/− mice compared to AM2+/+ mice (p < 0...