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PubMed2001

IL-1beta and IL-8 in human fetal membranes: changes with gestational age, labor, and culture conditions.

PROBLEM: Interleukin (IL)-1beta and IL-8 are associated with labor. This study aimed to characterize their concentrations in fetal membranes and any changes in these with advancing gestation and to define as to whether there are interactions between the membranes in their expression. METHOD OF STUDY: mRNA and protein content of amnion and choriodecidua at increasing gestations and before and after labor at term were quantified. Membranes were also collected before and after labor, separated, and cultured. Protein production was measured by ELISA. RESULTS: IL-1beta and IL-8 concentration increased in third trimester amnion and choriodecidua. Further increased expression of mRNA of both cytokines was found after labor in both membranes except IL-8 production by amnion. Choriodecidua produced more of each cytokine than amnion, however, no interaction between the membranes was demonstrated by culture. CONCLUSIONS: Increasing expression of IL-1beta and IL-8 in amnion and choriodecidua in the third trimester and after labor supports a role for these cytokines in the establishment of labor.

Amnion↗
PubMed2002

Expression and localization of aquaporin 1 and 3 in human fetal membranes.

OBJECTIVES: Aquaporins are a family of water-selective channels that facilitate fluid movement across cell membranes. Specifically, aquaporin 1 (AQP1) and aquaporin 3 (AQP3) have been found to be important in osmotic water movement across membranes. Our goal in this study was (1) to determine whether AQP1 or AQP3 messenger RNA are expressed in the chorioamniotic membrane and, if present, (2) to determine the precise membrane location of these aquaporins. STUDY DESIGN: Placentas were collected from women with intact membranes not in labor who underwent elective cesarean sections at term (37-40 weeks). The membranes (amnion and chorion) directly overlying the placenta were sampled as well as the free-floating reflected membranes. RNA and protein were isolated from the amnion and chorion. Reverse transcriptase-polymerase chain reaction, Western analysis, and immunohistochemistry were used to determine expression and localization of AQP1 and AQP3. RESULTS: AQP1 messenger RNA was found in amnion and chorion from both membrane locations. Western analysis also yielded positive results for amnion and chorion from both locations. Immunohistochemical localization of AQP1 showed it to be present on the apical aspect of the chorionic plate amnion. AQP3 protein was not found in the fetal membranes. CONCLUSIONS: AQP1 is present in the fetal membranes. AQP1 may play a role in water movement from the amniotic cavity across the placenta into the fetal circulation. Further studies are needed to clarify our understanding of the role of fetal membrane aquaporins in amniotic fluid homeostasis.

Amnion↗
PubMed2006

Production of an acellular amniotic membrane matrix for use in tissue engineering.

A clinical need exists for an immunologically compatible surgical patch with a wide range of uses including soft tissue replacement, body wall repair, cardiovascular applications, and as a wound dressing. This study aimed to produce an acellular matrix from human amniotic membrane for future assessment as a surgical patch and a delivery system for epithelial cells. A novel detergent-based protocol was modified to remove all cellular components from amnion to render it non-immunogenic. Amnion was harvested within 24 h after elective caesarean section (n = 12). One sample group remained fresh, whereas the other was treated with 0.03% (w/v) sodium dodecyl sulphate, with hypotonic buffer and protease inhibitors, nuclease treatment, and terminal sterilization, using peracetic acid (0.1% v/v). Fresh and treated amnion was analyzed histologically for the presence of cells, deoxyribonucleic acid (DNA), collagen, glycosaminoglycans (GAGs), and elastin. Quantitative analysis was performed to determine levels of GAGs, elastin, hydroxyproline, denatured collagen, and DNA. The biomechanical properties of the membrane were determined using uniaxial tensile testing to failure. Histological analysis of treated human amnion showed complete removal of cellular components from the tissue; the histoarchitecture remained intact. All major structural components of the matrix were retained, including collagen type IV and I, laminin, and fibronectin. Differences were observed between fresh and decellularized amnion in matrix hydroxyproline (34.7 microg/mg vs 49.7 microg/mg), GAG (42.5 microg/mg vs 85.4 microg/mg), denatured collagen (2.2 microg/mg vs 1.7 microg/mg), and elastin (359.2 microg/mg vs 490.8 microg/mg) content. DNA content was diminished after treatment. Acellular matrices were biocompatible, cells grew in contact, and there was no decrease in cell viability after incubation with soluble tissue extracts. In addition, no significant reduction in ultimate tensile strength, extensibility, or elasticity was found after decellularization. Removal of the cellular components should eliminate immunological rejection. The resulting matrix was biocompatible in vitro and exhibited no adverse effects on cell morphology or viability.

Amnion↗
PubMed2003

Fractalkine (FRK) levels in amniotic fluid and its production during pregnancy.

Fractalkine is a new CX(3)C chemokine that has chemoattractant activity for T cells, monocytes and natural killer (NK) cells. Western blot analysis revealed that fractalkine protein was detected as a 95 kDa band in both the amniotic fluid and the amnion during the second and third trimesters. Immunohistochemistry using an anti-fractalkine polyclonal antibody revealed positive staining of epithelial cells in amnion and trophoblasts in both the second and third trimesters. Neonatal urine also contained detectable amounts of fractalkine. RT-PCR detected fractalkine mRNA transcripts in the amnion. To determine whether fractalkine receptor (CX(3)CR1)-positive cells were present in amniotic fluid and amnion, we performed RT-PCR using specific primers for CX(3)CR1. CX(3)CR1-positive cells had migrated into the amniotic fluid and the amnion. The present findings suggest that fractalkine found in amniotic fluid may contribute to the immunodefence mechanism during pregnancy.

Amnion↗
PubMed2006

Increased adrenomedullin protein content and mRNA expression in human fetal membranes but not placental tissue in pre-eclampsia.

The relationship between Pre-eclampsia (PE) and placental production of Adrenomedullin (AdM) is not completely understood. This study measured placental and fetal membrane AdM protein concentrations by specific radioimmunoassay and mRNA expression by Northern blot analysis in samples obtained at either term or preterm gestation from women either in labour or not in labour. Samples were obtained from women with normotensive and pre-eclamptic pregnancies. There were significant increases in immunoreactive AdM protein concentration (pg/mg DNA) in choriodecidua and amnion of women with PE compared to normal pregnancy for the preterm not-in-labour group (choriodecidua: control 124 +/- 16, n = 10, PE 361 +/- 35, n = 10; amnion: control 94 +/- 12, n = 10, PE 153 +/- 19, n = 10) and for the term not-in-labour (choriodecidua: control 128 +/- 17, n = 14, PE 459 +/- 51, n = 8; amnion: control 112 +/- 15, n = 14, PE 253 +/- 57, n = 8) and in-labour (choriodecidua: control 531 +/- 74, n = 14, PE 881 +/- 188, n = 8; amnion: control 545 +/- 84, n = 14, PE 1008 +/- 230, n = 8) groups. AdM mRNA relative abundance was greater in preterm, not-in-labour choriodecidual samples in PE, but not in amnion. In addition, this study observed labour-associated increases in choriodecidual and amniotic irAdM in term pre-eclamptic and control patients. However, there were no significant changes in AdM protein or mRNA expressions between any of the groups for placental tissue. These results suggest that fetal membranes, but not placental, production of AdM is increased at the post-translational level during PE in preterm and term tissues and at the pre-translational level during PE in preterm tissues. Fetal membranes, AdM may play an important role in the regulation of feto-placental hemodynamics and fetal physiology during pre-eclampsia.

Adrenomedullin↗
PubMed1981

The maintenance of human amniotic membranes in culture.

A culture systems is described for the long-term maintenance of human amnion in vitro. This has been developed because of the need for an amnion organ culture to study immunological aspects of this extra-embryonic membrane as well as the increasing surgical use of amnion in wound healing. The intact amnion can be maintained for 2-3 weeks with 50-90% viability as determined by morphological and trypan-blue extraction techniques. This puts forward the feasability of developing an amnion bank for clinical investigations of wound healing as well as the possibility of in vitro studies of this membrane in the materno-fetal relationship in human pregnancy.

Amnion↗
PubMed1997

Detection of human defensins in the placenta.

PROBLEM: The placenta is a highly selective barrier against the hematogenous dissemination of infectious agents. Despite the presence of seemingly intact physical and immunologic barriers, infections nonetheless occur. These observations prompted the examination of placental tissue, amnion, and chorion for previously unrecognized protective mechanisms. METHOD OF STUDY: Messenger RNA from term placenta, amnion, and chorion were reverse transcribed using a 3' RACE adapter. 3' rapid amplification of cDNA ends (RACE)-polymerase chain reaction (PCR) was conducted on cDNA from these tissues to detect the presence of human defensins. Southern analysis and partial sequence analysis were subsequently performed to confirm identity. RESULTS: PCR amplification of placental, amnion, and chorion cDNA yielded a 468-bp product and a weakly detectable band of 300 bp. Southern analysis demonstrated two corresponding hybridizing bands in the placenta, amnion, and chorion but not from a negative cDNA control. Partial sequence analysis of the 468-bp product from placenta confirmed the presence of either defensin 1 or 3 in human placenta. CONCLUSIONS: The human placenta, amnion, and chorion express defensins at the level of transcription. These findings suggest that a novel and previously unrecognized mechanism of protecting the fetus against infection may be present within these tissues.

Amnion↗
PubMed2005

Prostaglandin H2 synthase-1 and -2 expression in guinea pig gestational tissues during late pregnancy and parturition.

Increased intrauterine prostaglandin (PG) production is crucial for the initiation of parturition. To investigate the mechanisms controlling intrauterine PG synthesis, we examined the expression of the key PG biosynthetic isoenzymes, PG-H2 synthase (PTGS)-1 and -2, in the amnion, visceral yolk sac (VYS), placenta and myo-endometrium of pregnant guinea pigs. This animal model was chosen because the hormonal milieu of pregnancy and the role of PGs in the hormonal control of parturition are similar to those in the human. PTGS1 mRNA abundance, measured by real-time RT-PCR, increased in the amnion and the placenta during the last third of gestation. During labour, PTGS1 mRNA levels decreased precipitously in all four tissues. PTGS1 protein abundance, assessed by immunoblotting, increased to high levels in the amnion and the placenta by the end of pregnancy and remained high during labour. PTGS2 mRNA expression was higher in the placenta than in the other tissues, but did not change before and during labour. PTGS2 protein expression decreased in the placenta and remained low in the other tissues during labour. Immunohistochemistry showed pervasive PTGS1 protein expression in the amnion and strong expression in the parietal yolk sac membrane (PYS) covering the placenta. PTGS2 was expressed in the PYS and the endometrium. The PTGS inhibitor piroxicam, administered in doses that inhibited PTGS1 but not PTGS2, significantly prolonged gestation. These data suggest that PGs generated by intrauterine PTGS1 are involved in the timing of birth in guinea pigs. The induction of PTGS1 in the amnion and the PYS is a critical event leading to labour in guinea pigs and models analogous changes in the human gestational tissues before labour.

Amnion↗
PubMed1984

Formation of unconjugated estrogens from estrone sulfate by dispersed cells from human fetal membranes and decidua.

Experiments were performed to determine the ability of isolated cells from human amnion, chorion, and decidua to hydrolyze estrone sulfate (E1S) to free estrone (E1) and estradiol (E2). Tissues were obtained from eight women after spontaneous onset of labor and vaginal delivery and from eight women undergoing elective cesarean section at term before the onset of labor. The tissues were obtained immediately after delivery, dispersed into isolated cell preparations using 0.05% collagenase, and incubated in Krebs-Ringer bicarbonate at 37 degrees C for 4 h. E1 and E1S were measured by specific RIAs. All three tissues from both patient groups produced E1 and E2 in a dose-dependent fashion from the E1S precursor. In both patient groups, chorion and decidua cells produced significantly more E1 and E2 than amnion cells. The chorion cells from the spontaneous labor group produced significantly more E1 than chorion cells from the cesarean section group. The chorion and decidua cells from the spontaneous labor group produced significantly more E2 than corresponding cells from the cesarean section group. The hydrolysis of E1S to E1 and E2 was significantly inhibited in a dose-dependent fashion by increasing concentrations of oxytocin and (Bu)2cAMP. Dispersed cells from amnion, chorion, and decidua also converted [3H]E1S to radiochemically pure [3H]E1. Chorion and decidua cells were significantly more active in this respect than amnion. The presence of excessive amounts of dehydroepiandrosterone sulfate (DHAS) did not significantly alter this reaction. All three tissues also hydrolyzed [3H]dehydroepiandrosterone sulfate, but in chorion and decidua, this activity was significantly less than the hydrolysis of [3H]E1S. We conclude that human amnion, chorion, and decidua possess the capability to hydrolyze E1S to free estrogen and that this activity in chorion and decidua is increased after spontaneous vaginal delivery. It is possible that this activity and its regulation are important factors in the local synthesis of free estrogen, which, in turn, may influence myometrial contractility.

Adult↗
PubMed1984

Binding sites for epidermal growth factor in human fetal membranes.

The present study demonstrates that human fetal membranes bind 125I-epidermal growth factor (125I-EGF), with chorion binding more than amnion. The chorion binding was also higher than that by decidua, but lower than in placenta. The lower binding by chorion compared to placenta was entirely attributable to a lower number of available EGF receptors and not to lower affinity. Chorion and placenta , but not amnion or decidua, from Cesarean section bound significantly more 125I-EGF when compared to tissues obtained after vaginal delivery. The binding of 125I-EGF to chorion exhibited dependency on time, temperature of incubation, pH of the incubation media, and amount of chorion protein. The 125I-EGF was not degraded during the binding reaction with chorion. The binding was specific in that unlabeled EGF inhibited 125I-EGF binding in a dose-dependent manner, whereas very high concentrations of other unlabeled hormones and growth factors had minimal effects on 125I-EGF binding. When some of these other hormones were tested for binding as tracers (125I-hCG, [3H]prostaglandin E1 and F2 alpha), neither chorion, amnion, decidua, nor placenta specifically bound these ligands. The 125I-EGF specific binding to chorion was saturable and a Scatchard plot of this data was curvilinear, which appears to be due to negative cooperativity. The apparent dissociation constant calculated from the initial slope of the plot was 0.20 nM, which is in excellent agreement with the concentration of unlabeled EGF required for half maximal inhibition of 125I-EGF binding, 0.26 nM. Autoradiography at the light microscope level revealed the presence of silver grains in amnion and chorion only when excess unlabeled EGF addition was withheld. The quantification of grains revealed the presence of a significantly (P less than 0.01) greater number of grains in chorion than in amnion, supporting the conclusion of the binding data. The physiological significance of EGF binding to fetal membranes and decidua is not known, but the considerable amount of EGF binding reported here suggests that they are target tissues for EGF.

Amnion↗
PubMed1994

Human fetal membrane contribution to the prevention of parturition: uterotonin degradation.

This investigation was conducted to evaluate the potential capacity of the human fetal membranes-decidua parietalis, and in particular the chorion laeve, to degrade uterotonins that are produced in amnion, are present in amniotic fluid, or both. The four uterotonins that have been evaluated most frequently as myometrial contractants potentially involved in the initiation of human parturition are prostaglandins, oxytocin, endothelin-1, and platelet-activating factor. We assessed the levels of mRNA and the specific activities (SAs) of enkephalinase (the plasma membrane endopeptidase that degrades endothelins) and prostaglandin dehydrogenase (PGDH) in human fetal membranes, i.e. amnion and chorion leave, and in decidua parietalis. The SA of oxytocinase (which inactivates oxytocin) in these tissues also was determined. The SA of enkephalinase in chorion laeve from all anatomical sites (singleton and diamnionic-dichorionic twin placentae) in all pregnancies studied (mean +/- SEM, 95 +/- 7.9 ng/min.mg protein; n = 28) is similar to that in human fetal kidney (89.5 +/- 2.8; n = 6). Kidney tissue is believed to be one of the richest sources of enkephalinase. The SAs of enkephalinase in amnion (18.3 +/- 2.3 nmol/min.mg protein; n = 29) and in decidua parietalis (31.8 +/- 6.7; n = 20) also were high, but significantly less than that in chorion leave. The level of enkephalinase mRNA in chorion laeve in singleton pregnancies is high, as is the SA of enkephalinase (111.9 +/- 10.6 nmol/min.mg protein; n = 17). In paired chorion laeve tissues from five diamnionic-dichorionic twin placentae, the SAs of enkephalinase in reflected chorion laeve (74 +/- 12.8; P < 0.06 compared with singletons) and fused chorion laeve (64.8 +/- 6.5; P < 0.001 compared with singletons) were similar. The SA of PGDH in reflected chorion leave (46.3 +/- 6.9 nmol/min.mg protein; n = 19) was significantly greater than that in decidua (16 +/- 5.5; n = 15). There was a significant correlation between the levels of PGDH mRNA and PGDH enzyme SA. In fused chorion laeve of diamnionic-dichorionic twin placentae, the SA of PGDH (14.9 +/- 7.3; n = 4) was much less than that in reflected chorion laeve of the same twin pregnancy (70.5 +/- 14.7; n = 4). PGDH mRNA was not detectable in amnion tissue (n = 5) by northern analysis, and the SA of PGDH (< 1.2 +/- 1.0; n = 6) in amnion was undetectable or near the lower limit of assay detection.(ABSTRACT TRUNCATED AT 400 WORDS)

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2000

Parathyroid hormone-related protein(1-34) in gestational fluids and release from human gestational tissues.

Parathyroid hormone-related protein (PTHrP) is present in fetal and gestational tissues, in which its proposed roles include stimulation of epithelial growth and differentiation, vasodilatation of the uteroplacental vasculature, relaxation of uterine muscle and stimulation of placental calcium transport. The aim of this study was to determine whether the release of PTHrP from gestational tissue explants was tissue specific. In addition, PTHrP concentrations were measured in maternal plasma, umbilical artery and vein plasma, and amniotic fluid from term, uncomplicated pregnancies before the onset of labour. PTHrP was detected in low concentrations in the mother, fetus and placental tissue. Amniotic fluid had ten times the PTHrP concentration compared with that in the maternal or fetal circulations. Using late pregnant human gestational tissues in an in vitro explant system, we found that amnion over placenta, choriodecidua, reflected amnion, and placenta released PTHrP into culture medium in progressively greater amounts over 24 h (P<0.05). This release was not associated with a loss of cell membrane integrity, as indicated by measurement of the intracellular enzyme, lactate dehydrogenase, in the incubation media. After 24 h incubation, the fetal membranes released significantly (P<0.05) greater amounts of PTHrP than did the placenta (placenta 3. 7+/-0.5 pmol PTHrP/g protein). Amnion over placenta released significantly more PTHrP (139.3+/- 43.1 pmol PTHrP/g protein) than did reflected amnion (29.0+/-8.3 pmol PTHrP/g protein) (P<0.05). This study unequivocally demonstrated that human gestational tissues release PTHrP and it was concluded that the main contributors to PTHrP in amniotic fluid were the human fetal membranes, particularly amnion over placenta. Fetal membrane-derived and amniotic fluid PTHrP are proposed to have stimulatory effects on epithelial growth and differentiation in fetal lung, gut, skin and hair follicles and paracrine effects on placental vascular tone and calcium transport.

Amnion↗
PubMed2000

[Shunt tube implantation combining amniotic membrane transplantation and implantation of Molteno implant for glaucoma after penetrating keratoplasty].

PURPOSE: To investigate the therapeutic effect of aqueous humor shunt implants with amniotic membrane transplantation on intractable glaucoma. METHODS: Glaucoma was induced in rabbits by the injection of alpha-chymotrypsin into the posterior chamber of the eyes. The rabbits were divided into four groups. Group A: control group, Group B: single shunt tube group, Group C: shunt tube with amniotic membrane transplantation group, Group D: shunt tube with amniotic supporter and amniotic membrane transplantation group. The intraocular pressure(IOP), histology and filterable ability of the tissue around the tubes were studied. The therapeutic effect of the three methods for the glaucoma was compared. From 1998 to 1999, 42 eyes of 41 patients with uncontrolled glacoma after penetrating keratoplasty were randomly assigned into two groups. One group (12 eyes) underwent implantation of shunt tube combining transplantation of amniotic membrane. The other group underwent implantation of a single plate Molteno implant. Clinical records were reviewed to ascertain postoperative IOP, visual acuities, number of medications. RESULTS: The IOP elevated after the operation and reached at the peak on the third day for all groups and then dropped slowly. The IOP was 33.34 +/- 5.54 mmHg (1 mmHg = 0.133 kPa) for Group A and 27.88 +/- 8.86 mmHg for Group B three months after the operation. There was no statistical difference between the two groups (P = 0.274). The IOP was 22.33 +/- 3.73 mmHg for Group C and there was statistical significant difference between Group C and Group A (P = 0.02) and no difference between Group C and Group B (P = 0.113). The IOP was 15.74 +/- 2.94 mmHg for Group D and there was statistical significant difference between Group D and Group A (P = 0.001) and Group B (P = 0.036). There was no difference between Group D and Group C (P = 0.09). The study of horseradish peroxidase penetrability indicated that there was peroxidase in the tissues around the tube with amniotic membrane transplantation and no peroxidase for simple shunt tube. The fibrous tissue near the tube was denser in simple shunt tube group than that in containing amnion groups. In clinic, the basic data existed no statistical difference between the two groups before surgery. The IOP was 54.42 +/- 9.65 mmHg in shunt tube with amnion group and 43.28 +/- 10.57 mmHg in simple plate Molteno implant group (P = 0.535) before operation. There was significant relativity of the visual acuity before and after the operation in two groups (r = 0.916, P = 0.002 and r = 0.962, P = 0.000). Most patients of the two groups had to use one or two anti glaucoma drugs. The overall success rates were 58.3% for shunt tube with amnion group and 66.7% for Molteno implant group (P = 0.73) within the follow-up period. Kaplan-Meier success analysis indicated one year cumulative success rates of 52.25% for shunt tube with amnion group and of 65.3% for Molteno implant group (P = 0.42). CONCLUSION: Amniotic membrane can inhibit proliferation of the scar around the shunt tube. Shunt tube implantation conbining amniotic membrane transplantation can significantly lowered the IOP of glaucoma. Combined using amnion supporter can expend shunt area and significantly reduce IOP of glaucoma. The effect of shunt tube implantation combining amniotic membrane transplantation has the similar result of single plate Molteno implant for the glaucoma after penetrating keratoplasty.

Adult↗
PubMed1992

Induction of fatty streak-like lesions in vitro using a culture model system simulating arterial intima.

In this study a two-compartment culture model of arterial intima was used for the in vitro induction of fatty streaklike lesions. The apparatus consisted of upper and lower compartments separated by a human amnion membrane stretched between them. Human umbilical vein endothelial cells (HUVECs) were cultured to confluence on the stromal surface of the amnion membrane. Maximal migration of blood mononuclear cells (MCs) through the HUVEC monolayer in response to a f-Met-Leu-Phe gradient was observed at 10(-8) mol/l; the migration was 3.29 times greater than that observed under the condition of random migration (control). In the study of MC transformation into lipid-laden cells in the amnion membrane (foam cell formation in 'arterial intima'), 10(6) MCs were incubated, in the presence of freshly prepared low-density lipoprotein (LDL; 100 microgram/ml). The lipid loading of MCs was time dependent. After 12 hours' incubation, 39% of the MCs that migrated into the amnion membrane contained a small number of lipid droplets, whereas the remaining 61% showed no lipid droplets. Only 1.7% of the cells contained a high number of lipid droplets in the cytoplasm and took on the appearance of foam cells. With time, the number of lipid-laden cells and the amounts of intracytoplasmic lipid droplets gradually increased. At 72 hours after incubation, 65.4% of the MCs were loaded with lipid droplets, and 20.9% of them, an eightfold increase over 12 hours of incubation, showed a foamy cell appearance. Because MCs consist of 70% monocytes and 30% lymphocytes, about 93% of the monocytes were filled with lipid after a 72-hour incubation. Ultrastructural examination showed that lipid-laden cells took on macrophage characteristics, such as wide and heterogeneous cytoplasm, indented nuclei, and abundant lysosomes. A minority of the MCs in the amnion were considered lymphocytes; they had scanty cytoplasm, round nuclei with abundant heterochromatin, no lysosomes, and no lipid vacuoles. In conclusion, the formation of an in vitro fatty streaklike lesion is demonstrated, and this is reminiscent of in vivo human atherogenesis.

Amnion↗
PubMed1990

[Levels of CA130 in maternal sera and amniotic fluid at various gestational ages].

We examined the CA130 concentration in the amniotic fluid, maternal sera, amnion, chorion, decidua and placenta. CA130 in the maternal sera showed an initial increase during early pregnancy, remained low from the 15th weeks of pregnancy until delivery, and then increased after term delivery (249u/ml, mean, n = 27) or mid-trimester abortions (844u/ml, n = 22). The CA130, concentration in the amniotic fluid was high in the mid-trimester and remarkably low at term. Among the tissues examined, amnion and decidua contained a relatively high concentration of CA130. Immunohistochemical examination also demonstrated abundant CA130 in the cytosol of amnion and decidua tissues. The pattern of changes in CA130 in amniotic fluid was similar to that in the amnion and decidua tissue. The results suggest that the amnion cells are the source of CA130 in the amniotic fluid and that the high concentration of CA130 in maternal serum after delivery originates in decidua tissue affected by the separation of the placenta.

Amnion↗
PubMed1989

Cellular permeation pathways in a leaky epithelium: the human amniochorion.

The presence of cellular permeation pathways in human fetal membranes at term was evaluated. Electrical parameters (transepithelial potential [TEP], and conductance [Gt], and intracellular potentials [cell PD]), and water and urea diffusional coefficients (Pdw, Pdu), were determined in Ussing-like chambers. In amniochorion, the TEP was practically 0 (0.1 +/- 0.03 mV), and the Gt very high (144 +/- 14 mS/cm2). The Cell PD of amnion cells was -37 +/- 3 mV. Increasing the [K+] of the amniotic perfusate between 5.8 and 125.8 mM depolarized the cells with a slope of 23 mV. The deletion of Na+ hyperpolarized the cells, whereas amiloride and ouabain depolarized them. The Pdw and Pdu were determined in intact amnion and chorion and in their epithelial cell layers. The Pdw/Pdu ratio in amnion was 4.0, and 7.0 in its cell layer; the ratio in chorion was 2.5, and 3.3 in its cell layer. The amniochorion is a leaky structure, but its cellular layers possess definite transcellular permeation pathways. The ionic conductances in amnion cells are complex, with the Cell PD being determined by at least K+ and Na+ conductances, and ouabain- and amiloride-sensitive pathways. The amnion is a more effective diffusional barrier to water and urea than chorion is; its diffusional characteristics are comparable to those of nystatin-treated lecithin: cholesterol bilayers and the membranes of human erythrocytes.

Amiloride↗
PubMed1986

The low hydroxyproline content of prematurely ruptured human fetal membranes.

Since collagen is one of the main factors responsible for the mechanical properties of soft tissue, we have determined the hydroxyproline content of the placental amnion, the free amnion and the chorion of 32 unruptured and 25 prematurely ruptured human fetal membranes. The hydroxyproline content of prematurely ruptured membranes was approximately 50% lower than in unruptured membranes. Hydroxyproline (microgram/mg lyophilized tissue), reported as mean +/- SD, was: 19.46 +/- 3.60 vs 37.53 +/- 8.93 for placental amnion; 16.97 +/- 3.93 vs 33.00 +/- 8.25 for free amnion, and 7.74 +/- 3.00 vs 13.23 +/- 3.95 for the chorion. This finding and the known decrease of hydroxyproline content of the amnion towards the end of gestation in normally evolving pregnancies suggest that an abnormally low collagen content may be the general cause of prematurely ruptured human fetal membranes.

Amnion↗
PubMed1985

The role of the yolk sac in craniofacial development of cultured rat embryos.

To study the role of the yolk sac and amnion in craniofacial development, the effects of opening the yolk sac and amnion on facial formation of rat embryos were examined in vitro. Rat embryos were cultured for 72 hr from day 11.5 of gestation using an improved rotation apparatus. In experiments, the yolk sac and amnion were opened at the time of explantation (day 11.5) in one group (D11 open) and were opened 24 hr after the beginning of the culture (day 12.5) in another group (D12 open). Cleft lip developed in 100% of cultured embryos when the yolk sac and amnion were opened at day 11.5 (D11 open). In the D12 open group, however, cleft lip occurrence decreased to 3.0%. Protein content, wet weight, and somite number of cultured embryos were not significantly different in the two groups. The results of this study demonstrate that it is beneficial to open the yolk sac and amnion after 24 hr in culture for normal facial formation of rat embryo cultured from day 11.5 of gestation.

Amnion↗