A unique monoclonal antibody 29A stains the cytoplasm of amniotic epithelia and cutaneous basement membrane

BACKGROUND

The basic function of epithelia is to provide a boundary between tissue and its external environment, and is achieved by a wide variety of components including extracellular molecules. Multiple monoclonal antibodies raised against epithelial antigens have helped identify a range of distinct, novel protein epitopes.

OBJECT

In this study, we raised a monoclonal antibody to detect a novel epithelial molecular component.

METHODS

We have produced a mouse monoclonal antibody using normal human amniotic tissue as an immunogen. The monoclonal antibody was subsequently immunohistochemically screened, and the target antigen was cloned using an immunoscreening method.

RESULT

In the course of the screening, we identified unique antibody staining patterns within the cytoplasm of a subset of amniotic cells at intervals within the normal placental epithelia. By immunoscreening, we identified this candidate gene as laminin receptor (LR). By dot blot analysis, this antibody reacted with recombinant LR. The same localization of the antigen and LR was proved by a double staining immunofluorescence test in the placenta. This monoclonal antibody unexpectedly demonstrated linear staining within the dermal-epidermal junction of normal human skin but failed to react within the keratinocyte cytoplasm.

CONCLUSION

We have produced and characterized a novel monoclonal antibody 29A that recognizes an LR-related molecule, which demonstrated a unique staining pattern. This monoclonal antibody might be a useful tool for further investigations into the epithelial tissues and the cutaneous basement membrane (BM).

Proteome analysis of human amnion and amniotic fluid by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Proteome analysis by 2-DE and PMF by MALDI-TOF MS was performed on human amnion and amniotic fluid at term. Ninety-two soluble and nineteen membrane proteins were identified from amnion. Thirty-five proteins were identified from amniotic fluid. Calgranulin A and B were found in all patients infected with Ureaplasma urealyticum, but not in any of the patients without infection, indicating that they are potential markers of intrauterine infection. Identity of calgranulin A and B was confirmed by MALDI-TOF/TOF MS. This study represents the first extensive analysis of the human amnion and amniotic fluid proteome at term and demonstrates that 2-DE and MALDI-TOF MS is a useful tool for identifying clinically significant biomarkers of problematic pregnancies.

The Expression of Insulin-like Growth Factor and Insulin-like Growth Factor Binding Protein mRNAs in Mouse Placenta

Insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) are paracrine regulators of tissue growth and development, and are expressed at the sites of biological action. To study the role of the IGFs and IGFBPs in mouse placental development, we determined the temporal and spatial expression patterns of the mRNAs at embryonic days 10.5 to 18.5 by in situ hybridization. IGF-II mRNA was expressed strongly in mesoderm and fetal blood vessels of early placenta and in labyrinthine trophoblast of later placenta. In the junctional zone, IGF-II mRNA was expressed first in spongiotrophoblasts, later strongly in glycogen cells and variably in giant cells. IGFBP-2 mRNA was expressed weakly in spongiotrophoblasts and glycogen cells. IGFBP-2, -5 and -6 mRNAs were detected in the stroma of the metrial gland. Myometrium expressed IGFBP-2 mRNA strongly, IGFBP-6 mRNA moderately and IGFBP-5 mRNA weakly. The endothelium of maternal blood vessels in decidua expressed IGFBP-3 and -5 mRNAs, and some deeper vessels expressed IGFBP-4 mRNA. In the yolk sac, IGF-II mRNA was expressed in endoderm and mesoderm, whereas IGFBP-1, -2 and -4 mRNAs were expressed only in endoderm, and IGFBP-4 mRNA in mesoderm. Strong expression of IGF-II mRNA in glycogen cells suggests a role in the autocrine/paracrine regulation of invasion. Similar to rat and guinea pig, but in contrast to man and primates, IGFBP mRNAs, except IGFBP-4, were not expressed in mouse decidua. However, IGFBP-3, -4 and -5 mRNAs were expressed in endothelium of maternal blood vessels, and IGFBP-2 and -6 mRNAs in myometrium, where IGFBPs may play a critical role in regulating trophoblast invasion. These findings suggest possible biological roles of the peptides at the feto-maternal interface.

Expression profile and protein levels of placental products as indirect measures of placental function in in vitro-derived bovine pregnancies

Bovine conceptus development and its association with placental proteins present in maternal, foetal and neonatal plasma and foetal (amniotic and allantoic) fluids were investigated inin vivo- andin vitro-produced (IVP) concepti and newborn calves. Females were superovulated to obtain control embryos, whereas IVP embryos were derived from establishedin vitroprocedures. Pregnant animals were slaughtered on days 90 or 180 of gestation or allowed to develop to term for the assessment of physical traits. Foetal, maternal and neonatal blood and foetal fluids were collected for the determination of bovine placental lactogen (bPL) and bovine pregnancy-specific protein B (bPSPB) concentrations. Placental transcripts for bPL and bPSPB, determined by quantitative RT-PCR, were elevated in IVP placentomes. No major physical differences were observed between groups on day 90, but concentrations of bPL and bPSPB were higher in foetal plasma and allantoic fluid of IVP concepti in day 180 pregnancies, which were correlated with larger uterine and conceptus traits. Maternal concentrations of bPL in IVP pregnancies were lower than controls during the last 8 weeks of gestation, to become similar as parturition approached. Newborn IVP calves and foetal membranes were larger and displayed higher concentrations of plasma bPL than controls (10 and 60 min after birth). Our results indicated that differential patterns of secretion of bPL and bPSPB into the maternal and foetal systems occurred at distinct stages of gestation, and these were associated with altered conceptus development afterin vitroembryo manipulations, indirectly demonstrating deviations in placental function in IVP pregnancies.

[Quantitative determination of vitamin A levels in frozen preserved human amniotic membrane]

PURPOSE

Retinoids are associated with cell proliferation and differentiation. The levels of retinoids (vitamin A and its derivatives) in human amniotic membrane (AM) were measured to investigate whether endogenous retinoids in AM might contribute to the process of wound healing of the keratoconjunctival epithelium in AM transplantation.

SUBJECTS AND METHODS

Retinoids were extracted from AM obtained from three patients following cesarean section. Retinoids including retinol (ROL), retinylaldehyde (RAL), retinoic acid(RA), and retinyl palmitate(RP) were analyzed using a reverse-phase high performance liquid chromatograph equipped with a multi-wavelength detector or fluorescence detector.

RESULTS

ROL was identified and detected in AM at a concentration of 9.42 2.75(mean +/- standard deviation) ng/g wet tissue. No other retinoids, were detected.

CONCLUSION

Among the retinoids tested, only retinol was detected at low levels in human AM tissues. Based on these results, endogenous retinoids in AM probably have little effect on wound healing of the keratoconjunctival epithelium in AM transplantation.

An Investigation into the Composition of Amniotic Membrane Used for Ocular Surface Reconstruction

PURPOSE

Cultivated limbal epithelial transplantation using an amniotic membrane (AM) carrier is now widely used for ocular surface reconstruction. The reasons for the exceptional success of AM as a carrier are not fully understood but are believed to be related to its unique composition. In this project we characterize, at the ultrastructural level, the extracellular matrix (ECM) components present in AM. We also compare the distribution of ECM components of cellular AM with that of denuded AM.

METHODS

Scanning, transmission, and atomic force microscopy was used to examine the structure of cellular and denuded amniotic membranes. Immunogold labeling with a panel of antibodies against ECM molecules was carried out on cellular and denuded AM.

RESULTS

Heparan sulfate, fibronectin, and laminin were present at high concentration in the lamina densa, Collagen IV was the major component of the basal lamina. Type I collagen was confined to the stroma along with significant amounts of keratan and chondroitin sulfate. Both cellular and denuded AMs had similar distributions of the ECM components.

CONCLUSIONS

We were able to determine the distribution of ECM molecules in the lamina densa, basal lamina, and stroma of AM at the ultrastructural level. The removal of amniotic epithelial cells using our protocol does not appear to have any significant effects on the structure of the basal lamina or the distribution of ECM components.

Optimised two-dimensional electrophoresis procedures for the protein characterisation of structural tissues

The protein analysis of structural tissues is typically highly problematic. Amniotic membrane displays unique wound healing and anti-scarring properties; however, little is known concerning its active protein content. The structural nature of amniotic membrane necessitated development and extensive optimisation of the entire two-dimensional (2-D) workflow. Proteins were extracted using powerful solubilisation buffers and analysis carried out using 2-D electrophoresis followed by mass spectrometry (MS) identification. Preservation and processing resulted in prefractionation of soluble from structural and membrane-associated proteins. Enhanced protein solubility was achieved by cysteine blocking using both N,N-dimethylacrylamide (DMA) alkylation and bis(2-hydroxyethyl) disulphide (HED); an alternative procedure for the effective application of HED is demonstrated. The benefits of precipitation and cup-loading versus in-gel rehydration were also assessed, with procedures for the employment of HED with the latter described. Following optimisation, a representative sample 21 proteins were identified from amniotic membrane using MS verify procedures were MS-compatible. Our results demonstrate that techniques for the reproducible separation of proteins from a proteinaceous structural tissue have been optimised. Briefly, proteins are extracted using a thiourea/urea extraction buffer containing carrier ampholytes, dithiothreitol (DTT), and 3-(cyclohexylamino)-1-propanesulfonic acid (CHAPS). After DMA alkylation, proteins were precipitated (using the 2-D clean-up kit from Amersham Biosciences) and resolubilised in extraction buffer containing a lower concentration of DTT. Samples were either cup-loaded onto rehydrated HED-containing strips or rebuffered into HED-containing buffer followed by in-gel rehydration.

Progesterone receptor expression in human decidua and fetal membranes before and after contractions: possible mechanism for functional progesterone withdrawal

In humans, progesterone levels are sustained before the onset of labour. Therefore, the mechanism for parturition that has been proposed for humans is 'functional' progesterone withdrawal. Immunohistochemical staining for the progesterone receptor (PR) was positive in the decidua with a decline after contractions began. Western blot analysis revealed a number of PR isoforms expressed in the decidua, with the PR-B form being dominant. After contractions began, all PR isoforms decreased sharply. PR-B and PR-A decreased by 85.8% +/- 6.7 and 78.2% +/- 7.1, respectively (P < 0.001). Incubation of decidua with Prostaglandin F2alpha 1.0 microg/ml decreased the expression of all forms of PR isoforms. PR-B was reduced by 64% +/- 6.09 (P < 0.01); PR-A was reduced by 77% +/- 5.9 (P < 0.05), while PR-C was reduced by 80% +/- 7.24 (P < 0.05). Progesterone (80 microg/ml) increased the PR-B, PR-C the 45 and 36 kDa isoforms to 150% +/- 7.89, 210% +/- 12.4, 270% +/- 9.7 and 216% +/- 13.5, respectively (P < 0.05). In immunohistochemical studies, the PR was not identified in the amnion or in the chorion, regardless of the presence or absence of contractions. Western blot analysis demonstrated that PR-C (60 kDa) and the 36 kDa isoforms were dominant in the amnion. After contractions began, PR-A decreased significantly by 61.9% +/- 7.1 (P < 0.001).

Soluble lumican glycoprotein purified from human amniotic membrane promotes corneal epithelial wound healing

PURPOSE

To purify and characterize the glycoprotein lumican, isolated from human amniotic membrane (AM), and to examine its efficacy in treating corneal epithelium debridement.

METHODS

An affinity-purified, anti-human lumican antibody-conjugated protein A Sepharose column was used to purify soluble lumican protein from human AM. The purified AM lumican was characterized by two-dimensional and SDS gel electrophoresis, plus Western blot analysis with anti-lumican antibody. The effects of lumican on corneal epithelial wound healing were examined in an organ culture mouse eye model.

RESULTS

Lumican was found to be abundantly present in the stroma of human AM. It was extracted from the AM by isotonic, 1 M NaCl, and 4 M guanidine HCl solutions, suggesting that it is present in both the soluble and matrix-bound states. In two-dimensional gel electrophoresis, the 50-kDa human amniotic lumican purified by antibody-conjugated affinity chromatography migrated in a smear between pH 3.0 and 6.0. After endo-beta-galactosidase digestion, it existed as a single core protein at pH 6.0, suggesting that native human amniotic lumican is a glycoprotein with short sugar moiety. Addition of purified human AM lumican to cultured medium promoted re-epithelialization and enhanced cell proliferation of wild-type mouse corneal epithelial cells in an organ culture. In lumican-knockout (lum(-/-)) mice, the effect of human lumican on promoting corneal epithelial wound healing was even more dramatic than in wild-type mice.

CONCLUSIONS

The diversified functions of lumican include modulation of epithelial cells in wound healing and serving as an extracellular matrix component. Administration of lumican may be beneficial for treating epithelial defects in the cornea and other tissues.

Dansylation of tryptic peptides for increased sequence coverage in protein identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometric peptide mass fingerprinting

A database search using peptide mass fingerprints obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry leads to protein identification with incomplete sequence coverage, because certain peptides are preferentially desorbed/ionized and some are not detected at all. We show that certain tryptic peptides mainly with C-terminal arginine not detected before derivatization become detectable upon dansylation. Others, mainly with C-terminal lysine, are suppressed. An increase in protein sequence coverage and protein identification score by combined data from underivatized and dansylated peptides in database search is demonstrated using human amnion proteins (human serum albumin precursor, calmodulin, collagen alpha 2(VI) chain precursor, galectin-3) separated by two-dimensional gel electrophoresis as well as femtomole amounts of BSA in solution.

Altered expression of IGFs and IGF-binding proteins during intrauterine growth restriction in guinea pigs

The IGF system is one of the most important endocrine and paracrine growth factor systems that regulate fetal and placental growth. We hypothesized that intrauterine growth restriction (IUGR) in guinea pigs is mediated by the altered expression of IGFs and/or IGF binding protein (BP) mRNAs in tissues and is related to growth of specific tissues. IUGR was induced by unilateral uterine artery ligation on day 30 of gestation, and fetal plasma, amniotic fluid and tissue samples were collected at 55-57 days (term about 68 days) from paired IUGR and control fetuses (n=6). Western ligand blotting and immunoblotting were used to compare IGFBP levels in plasma and amniotic fluid. Total RNA was extracted from placenta and fetal tissues, and the relative abundance of IGF-II and IGFBP-1-6 mRNA was determined by Northern blotting, using species-specific probes where available. IUGR fetuses had decreased (P<0.01, by Student's t-test) placental weight and body weight with an increase in the brain:liver weight ratio. The principal IGFBPs in fetal plasma migrated at 40-35, 30 and 25 kDa and were identified as IGFBP-3, -2 and -4 respectively. IUGR was associated with elevated plasma IGFBP-2 and IGFBP-4 and reduced IGFBP-3 levels. IGFBPs were detected at low levels in amniotic fluid of control fetuses but at higher levels in IUGR fetuses. In IUGR placentae, there was a small increase in IGFBP-4 mRNA (P<0.05). IGFBP-2 mRNA increased (P<0.001) in liver of IUGR fetuses. IGF-II and IGFBP mRNA expression did not change in fetal muscle. The results are consistent with reduced IGF action, directly or through inhibition by IGFBPs, particularly by circulating and tissue IGFBP-2, as a potential causal factor in decreased growth of the placenta and certain fetal tissues.

Raised prorenin and renin concentrations in pre-eclamptic placentae when measured after acid activation

AIM

The aim of the study was to ascertain if there was any difference in the levels of prorenin and active renin between pre-eclamptic and normotensive feto-placental tissues.

METHODS

Supernatants of homogenates from fresh, vaginally delivered placentae from 15 normotensive and 15 pre-eclamptic women were measured for renin concentration (RC), prorenin concentration and renin activity (RA). RA and RC were measured in the absence and presence of nephrectomised sheep plasma, respectively. Prorenin was estimated as the difference between renin concentration in the sample before and after acid activation. All concentrations are expressed as rate of angiotensin generation (ng/ml/h). Angiotensin I was measured by radioimmunoassay. Statistical analysis was performed using Student's 't' test for unpaired samples. All results are presented as mean+/-SEM.

RESULTS

The concentrations of renin and prorenin were highest in the chorion laeve when compared to amnion and placenta (p < 0.01) in both the groups. Furthermore, the concentrations of renin and prorenin were significantly higher in all the tissues from women with pre-eclampsia (p < 0.01).

CONCLUSION

Renin and prorenin levels are raised in the placental tissues from women with pre-eclampsia. With recent evidence suggesting that both prorenin and renin may have cellular effects independent of angiotensin II generation, there is a need for further study into its role in placentation.

Psoriasin, a calcium-binding protein with chemotactic properties is present in the third trimester amniotic fluid

Psoriasin is a small calcium-binding protein first found in psoriatic lesions and also up-regulated in other inflammatory skin diseases and cancer tissues. Psoriasin is also present in the fetal epithelial cells. Its biological function is unclear, but there is both in vitro and in vivo evidence for its chemokine-like activity. The aim of the present study was to find whether psoriasin could be found in the amniotic fluid and thus could have long-range immunobiological effects. Two recombinant psoriasins were prepared, one in Escherichia coli, the other one in Pichia pastoris. The former was used to produce a rabbit antiserum against psoriasin. Fractionation of full-term amniotic fluids with polyacrylamide gel electrophoresis (PAGE) and gel filtration associated with immunodetection with the antiserum were used to identify a protein compatible with the size of psoriasin. The identity of psoriasin was further verified by mass spectrometric analysis. Expression of psoriasin in cells of the amniotic membranes was detected with nested RT-PCR. Because of its chemokine-like activity, psoriasin present in the amniotic fluid might have consequential immunobiological effects during the fetal development.

The basement membrane zone in patients with systemic lupus erythematosus: immunofluorescence studies in the skin, kidney and amniochorion

Histological studies suggest that the basement membrane zone (BMZ) is the main target of tissue pathology in cutaneous lupus erythematosus (LE). The BMZ is characteristically thickened and is the site of deposition of autoantibodies in LE. Alteration of some (BMZ) macromolecules is implicated in the pathology of several bullous skin diseases. A major component of BMZ is heparan sulphate proteoglycan (HSPG) which was found reduced in the skin of some patients with systemic lupus erythematosus (SLE) and in the kidney of mice with lupus nephritis. Similar to the skin, amnion is derived from the ectodermal germ layer during embryogenesis and expression of BMZ components of amniochorion was not previously studied in SLE. The aim of the present study was to investigate the expression of major BMZ macromolecules in the skin, kidney and amnioplacentae obtained from patients with SLE and compare these findings with organ biopsies from unaffected individuals. In addition, determining whether the differences in composition and distribution of BMZ macromolecules in these organs correlate with certain patterns of deposition of immunoreactants could contribute to our understanding of the mechanism of deposition of immunoreactants in SLE. In some patients with SLE, reduced expression of HSPG in nonlesional skin was reported previously. These changes of heparan sulphate might be important in the pathogenesis of LE. Therefore, the aims of this study are to confirm the previous finding and to compare HSPG expression between lesional and nonlesional LE skin. The unique features of each BMZ could contribute to the deposition or binding of positively charged immune complexes and explain the different patterns of immunofluorescence. Frozen sections of skin, kidney and amniochorion obtained from patients with SLE were investigated by indirect immunofluorescence technique using monoclonal antibodies (Moab) to determine the expression of major components of the BMZ. Heparan sulfate expression is reduced in the skin and, to a lesser extent, in the kidney in patients with SLE. There was no correlation between the kidney and skin heparan sulfate expression within the same patient. The BMZ composition in amniochorionic membrane ofplacentae from women with SLE was normal. Heparan sulfate may be one of the major targets for immunoglobulin deposition in the skin of patients with SLE. The processes of immunoglobulin deposition in SLE may be more complex in that there was no correlation between heparan sulfate expression in the skin and kidney of the same patient.

Biocompatible collagen scaffolds from a human amniotic membrane: physicochemical and in vitro culture characteristics

A reconstituted collagen membrane from human amnion has been investigated as a source of collagen matrix, which could be used as a substratum for culturing human fibroblasts. The suitability of pepsin-solubilized reconstituted human amniotic membrane, before and after cross-linking with chitosan, as a dermal matrix for culturing fibroblast was assessed by morphologic, physicochemical, cytotoxic and histochemical methods. Measurement of thermodynamic behaviour, by differential scanning calorimetric (DSC) and thermogravimetric analysis (TGA), and tensile strength suggested that the cross-linked membrane had sufficient elasticity to serve as an efficient dermal substrate for in vitro culture of fibroblasts. Fibroblasts cultured on the chitosan cross-linked collagen membrane had good adherence, retaining their morphology as indicated by microscopic analysis. Proliferation of fibroblasts. observed on this membrane affirms its non-toxic nature. These results support the application of reconstituted human amniotic collagen membrane as collagenous scaffolds to culture fibroblasts in vitro.

[Altered of zinc finger proteins expression in FL cells following benzo [a] pyrene treatment]

OBJECTIVE

To understand benzo[a]pyrene (B[a]P) mediated cellular responses, and to provide clues to explore molecular mechanism of mutagenesis and carcinogenesis induced by B[a]P.

METHODS

Two-dimensional electrophoresis (2-DE) was used to investigate the protein expression levels of FL cells after B[a]P exposure, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) combined with database search was applied to identify the differentially expressed proteins.

RESULT

Statistical analysis showed that the volumes of 47 protein spots were altered after B[a]P treatment (P<0.05) and 23 proteins were successfully identified, including zinc finger proteins, SWI/SNF related protein, Bromo domain containing domain and other proteins.

CONCLUSION

These affected proteins may be involved in the cellular responses to B[a]P exposure, and may mediate the B[a]P induced mutagenesis and carcinogenesis.

[Proteomic analysis of cellular responses to low concentration of N-methyl-N'-nitro-N-nitrosoguanidine in human amnion FL cells]

OBJECTIVE

To investigate the protein profile after treatment of low concentration of N- methyl-N'-nitro-N-nitrosoguanidine (MNNG) in human FL cells.

METHODS

After MNNG treatment, whole cellular proteins were separated using two-dimensional gel electrophoresis and visualized by silver staining; the digitized images were analyzed with 2D analysis software. The differentially expressed protein spots were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS).

RESULT

More than 60 proteins showed significant changes in MNNG-treated cells compared to control cells (DMSO treatment). There were 18 protein spots detected only after MNNG treatment, while 13 protein spots were detected only in the control cells. Moreover, the levels of another 31 proteins were either increased or decreased in MNNG-treated FL cells. And some of the proteins were identified by MALDI-TOF-MS.

CONCLUSION

There are significant alterations of protein profile after MNNG attack.

Endothelin-1 and macrophage colony-stimulating factor are co-localized in human amnion membrane cells and secreted into amniotic fluid

We have examined the cellular localization and human amniotic fluid content of endothelin-1 (ET-1) and macrophage colony-stimulating factor (M-CSF). The study material consisted of amniotic fluid from 20 patients referred for amniocentesis, and placental samples from normal deliveries. ET-1 and M-CSF were analysed by radioimmunoassay and enzyme-linked immunosorbent assay respectively. The cellular localization of ET-1 and M-CSF in the amnion membranes was analysed by double-labelling immunocytochemistry using fluorescein isothiocyanate- and Cy3-labelled secondary antibodies. Release of ET-1 and M-CSF was studied in cultured amniocytes. We found that the mean +/- SD concentrations of ET-1 and M-CSF in fetal amniotic fluid were 45.6 +/- 17.3 pmol/l (range 16.8-85.5) and 7323 +/- 3415 ng/l (range 2640-12 110) respectively. Double-labelling immunocytochemistry showed that both M-CSF and ET-1 were co-localized in the same cells to a high extent. Further analysis revealed that levels of M-CSF, but not ET-1, were significantly correlated with pregnancy length. Both M-CSF and ET-1 were released from cultured amniocytes in response to interleukin-1. These findings show that ET-1 and M-CSF are partly co-localized to specific cells in the human amniotic membrane. As both M-CSF and ET-1 were released from cultured amniocytes in vitro, this suggests that they both may be secreted into fetal amniotic fluid in vivo as well.

Labour-associated changes in adrenomedullin content in human placenta and fetal membranes

The aim of the present study was to determine the effects of labour and mode of delivery on human placental and fetal membrane content of adrenomedullin (AdM). Placentas and fetal membranes were collected either at term or pre-term gestation from women either in labour or not in labour, and AdM was measured in tissue extracts by specific RIA. There were significant increases in AdM concentrations in amnion and choriodecidua for the in-labour group compared with the not-in-labour group for both pre-term and term gestations. There was no difference in AdM concentration in placental tissue between labour groups. This study provides evidence that fetal membrane AdM is increased in amniotic and choriodecidual tissues in response to labour, and suggests that it may play a role during human labour.

Placental expression of estrogen receptor beta and its hormone binding variant--comparison with estrogen receptor alpha and a role for estrogen receptors in asymmetric division and differentiation of estrogen-dependent cells

During human pregnancy, the production of 17-beta-estradiol (E2) rises steadily to eighty fold at term, and placenta has been found to specifically bind estrogens. We have recently demonstrated the expression of estrogen receptor alpha (ER-alpha) protein in human placenta and its localization in villous cytotrophoblast (CT), vascular pericytes, and amniotic fibroblasts. In vitro, E2 stimulated development of large syncytiotrophoblast (ST) aggregates. In the present study we utilized ER-beta affinity purified polyclonal (N19:sc6820) and ER-alpha monoclonal (clone h-151) antibodies. Western blot analysis revealed a single approximately 52 kDa ER-beta band in chorionic villi (CV) protein extracts. In CV, strong cytoplasmic ER-beta immunoreactivity was confined to ST. Dual color immunohistochemistry revealed asymmetric segregation of ER-alpha in dividing villous CT cells. Prior to separation, the cell nuclei more distant from ST exhibited high ER-alpha, while cell nuclei associated with ST showed diminution of ER-alpha and appearance of ER-beta. In trophoblast cultures, development of ST aggregates was associated with diminution of ER-alpha and appearance of ER-beta immunoreactivity. ER-beta was also detected in endothelial cells, amniotic epithelial cells and fibroblasts, extravillous trophoblast (nuclear and cytoplasmic) and decidual cells (cytoplasmic only). In addition, CFK-E12 (E12) and CWK-F12 (F12) monoclonal antibodies, which recognize approximately 64 kDa ER-beta with hormone binding domain, showed nuclear-specific reactivity with villous ST, extravillous trophoblast, and amniotic epithelium and fibroblasts. Western blot analysis indicated abundant expression of a approximately 64 kDa ER-beta variant in trophoblast cultures, significantly higher when compared to the chorionic villi and freshly isolated trophoblast cell protein extracts. This is the first report on ER-beta expression in human placenta and cultured trophoblast. Our data indicate that during trophoblast differentiation, the ER-alpha is associated with a less, and ER-beta with the more differentiated state. Enhanced expression of approximately 64 kDa ER-beta variant in trophoblast cultures suggests a unique role of ER-beta hormone binding domain in the regulation of trophoblast differentiation. Our data also indicate that asymmetric segregation of ER-alpha may play a role in asymmetric division of estrogen-dependent cells.

Extracellular matrix of human amnion manufactured into tubes as conduits for peripheral nerve regeneration

The human amnion consists of the epithelial cell layer and underlying connective tissue. After removing the epithelial cells, the resulting acellular connective tissue matrix was manufactured into thin dry sheets called amnion matrix sheets. The sheets were further processed into tubes, amnion matrix tubes (AMTs), of varying diameters, with the walls of varying numbers of amnion matrix sheets with or without a gelatin coating. The AMTs were implanted into rat sciatic nerves. Regenerating nerves extended in bundles through tubes of 1-2 mm in diameter and further elongated into host distal nerves 1-3 weeks after implantation. Morphometrical analysis of the regenerated nerve cable at the middle of each amnion matrix tube 3 weeks after implantation was performed. The average numbers of myelinated axons were almost the same (ca. 80-112/10(4) microm(2)) in AMTs of 1-2 mm in diameter, as in the normal sciatic nerve (ca. 95/10(4) microm(2)). No myelinated fibers were found in AMTs composed of multiple thin tubes of 0.2 mm in diameter. The myelinated axons were thinner in implanted tubes than those in the normal sciatic nerve. The rate of occurrences of myelinated axons less than 4 microm in diameter was significantly higher in the AMTs, whereas axons in the normal sciatic nerve were diverse in distribution, with the highest population at 8-12 microm in diameter. Reinnervation to the gastrocnemius muscle was demonstrated electrophysiologically 9 months after implantation. It was concluded that the extracellular matrix sheet from the human amnion is an effective conduit material for peripheral nerve regeneration.

Effect of labor on glucocorticoid receptor (GR(Total), GRalpha, and GRbeta) proteins in ovine intrauterine tissues

OBJECTIVE

Activation of the fetal hypothalamic-pituitary-adrenal axis and a concurrent increase in plasma cortisol concentration plays a crucial role in parturition in sheep. The effects of cortisol on intrauterine tissues are mediated, in part, by glucocorticoid receptors (GR). In the present study, we determined the temporal and tissue-specific expression of GR(Total), GRalpha, and GRbeta isoforms in ovine placenta, fetal membranes, and uterus during the onset and progression of labor.

METHODS

Intrauterine tissues were collected from following three groups of pregnant ewes at term (147-149 days of gestation): animals not in labor (NIL; 140-145 days; n = 5), early labor (EL; 143-149 days; n = 6), and active labor (L; 145-149 days; n = 6). They were analyzed for GR(Total), GRalpha, and GRbeta by immunohistochemical and Western blot analyses.

RESULTS

GR(Total), GRalpha, and GRbeta proteins were present in trophoblast cells but not maternal tissue of the placentome. GRalpha and beta were distinctly expressed in trophoblast nuclei and cytosol, respectively. GR(Total), GRalpha, and GRbeta were also detected in amnion epithelial cells and chorionic epithelium of the fetal membranes, and the maternal endometrial epithelium. GR(Total) and GRalpha were also present in amnion mesenchymal and glandular epithelium. GR(Total) and GRalpha (95 kDa) protein levels were significantly (P < .05) higher during labor; GRbeta (90 kDa) levels remained unchanged.

CONCLUSION

The temporal and tissue-specific pattern of GR expression within ovine intrauterine tissues during labor implicates GR in regulating cortisol action to induce enzymatic changes controlling labor in sheep.

Relaxin causes proliferation of human amniotic epithelium by stimulation of insulin-like growth factor-II

OBJECTIVE

The study was conducted to determine whether relaxin has a proliferative effect on amniotic epithelial cells and to show that this effect is caused by its stimulation of the insulin-like growth factor-II (IGF-II) gene.

STUDY DESIGN

Immunolocalization and Northern analysis were used to confirm the expression of IGF-II by the fetal cells in the membranes. Human amniotic epithelial (WISH) cells were treated with doses of IGF-II or human relaxin and their proliferative effects measured. The mechanism of the effect of relaxin on cellular proliferation was studied with the use of an IGF-II-blocking antibody and Northern analysis for IGF-II gene expression after treatment with relaxin. An in vivo correlate was sought by quantitation of relaxin gene expression in 10 fetal membranes from women with normally grown and large for gestational age infants.

RESULTS

The amniotic epithelial and cytotrophoblast cells of the fetal membranes expressed IGF-II, as did the amniotic epithelial-like (WISH) cell line. Treatment of WISH cells with IGF-II or relaxin caused a significant (P <.03) and dose-related increase in WISH cell proliferation over 5 days. The concurrent treatment with a blocking antibody to IGF-II significantly decreased the proliferative response to IGF-II (P <.002) and relaxin (P <.002). Treatment with relaxin caused a significant increase (P <.003) in the transcription of IGF-II in 24 hours. In fetal membranes, the levels of relaxin gene expression correlated with fetal membrane surface area (r = 0.76) and was significantly greater (P <.008) in the membranes from macrosomic infants (4020-4729 g) compared with those normally grown (2855-3830 g).

CONCLUSION

IGF-II and relaxin both caused the proliferation of WISH cells. Concurrent treatment with an IGF-II-blocking antibody abrogated the proliferative effects of both hormones. Relaxin increased the transcription of IGF-II, and its expression levels in the fetal membranes correlated with the membrane surface area as well as neonatal birth weight. These data suggest that relaxin is a growth factor for the fetal membranes.

Origin of amnion and implications for evaluation of the fetal genotype in cases of mosaicism

OBJECTIVE

To investigate presence of trisomy in amniotic epithelium (uncultured amnion) and mesenchyme (cultured amnion) from mosaic cases to understand the origins of these tissues and their relationship to pregnancy outcome.

METHODS

Polymerase chain reaction (PCR) of microsatellite loci was used to determine the presence of trisomy (of meiotic origin only) in amnion samples from 33 placentas previously ascertained because of a prenatal diagnosis of trisomy mosaicism that was predominantly confined to the placental tissues.

RESULTS

In 16 (48%) of 33 cases, trisomy was confirmed to be present by molecular analysis of uncultured amnion. In contrast, cytogenetic analysis of cultured amnion showed trisomy in only 2 of 20 informative cases. The molecular detection of trisomy in amnion was strongly associated with poor pregnancy outcome (intrauterine growth restriction, fetal anomalies and/or intrauterine/neonatal death) even when analysis was limited to cases negative for the trisomy on amniotic fluid (N = 22, p = 0.0005).

CONCLUSIONS

We infer that amniotic mesenchyme (usually diploid) derives from early embryonic mesoderm of the primitive streak and not from the hypoblast as is commonly cited. Trisomy in amniotic epithelium suggests that high numbers of abnormal cells were present in the epiblast, and this correlates with poor outcome even when the subsequently derived fetus and amniotic mesenchyme appear to carry only diploid cells.

Collagen messenger RNA expression in the human amniochorion in premature rupture of membranes

OBJECTIVE

It has been suggested that there is a decrease in the collagen content of the fetal membranes when there is premature rupture of the membranes before the onset of labor. This study was designed to determine whether decreased amniochorion collagen production (as measured by reduced amounts of messenger RNA) or alterations in relative production of different fibrillar and nonfibrillar collagens are associated with premature rupture of the membranes.

STUDY DESIGN

Fetal membranes were collected after preterm (24-36 weeks of gestation) and term (> or =37 weeks of gestation) deliveries both with and without premature rupture of the membranes. Specimens with evidence of histologic chorioamnionitis were excluded. The messenger RNA levels for fibrillar collagen types I, III, and V and fibril-associated collagens with interrupted triple-helices types XII and XIV were measured with relative quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

The messenger RNA levels for fibrillar collagens decreased with advancing gestational age. Preterm premature rupture of membranes was associated with increased messenger RNA levels for fibrillar collagens and fibril-associated collagens with interrupted triple-helices collagen XII, but not type XIV. The greatest change in relative amounts of collagen messsenger RNA was demonstrated by an increased type I/XIV ratio, which was due to the up-regulation of type I levels, but not type XIV levels.

CONCLUSION

A rise in fibrillar collagen production (messenger RNA) for types I, III, and V and fibril-associated collagens with interrupted triple-helices collagen type XII is observed with preterm premature rupture of the membranes. There is no evidence for a similar up-regulation of messenger RNA for fibril-associated collagens with interrupted triple-helices collagen type XIV. The rise in the collagen I/XIV messenger RNA ratio in preterm premature rupture of the membranes may result in collagen fibrils without enough stabilizing fibril-associated collagens with interrupted triple-helices type XIV on the fibril surface to maintain structural integrity.

Prenatal diagnosis of Menkes disease by genetic analysis and copper measurement

Carrier detection for 12 women and prenatal diagnosis for six fetuses in Japanese families with a patient with Menkes disease (MNK) were performed by gene analysis and/or measurement of the copper concentration in cultured cells. Six out of eight mothers of MNK patients were carriers while two (25%) were not carriers. Two unrelated patients showed the same mutation (R986X): one patient's mother was a carrier while the other was not. One male and three female fetuses did not have the same mutant allele as the respective MNK proband and have been healthy since birth. One female fetus had the same mutant allele as her affected brother. Gene analysis is very useful and reliable, although such examination is only indicated in families in which a mutation has been identified. In one family in which a mutation in ATP7A was not found, cultured amniocytes from a male fetus had a high copper concentration. Thus after his birth, the biochemical findings confirmed the presence of MNK and early treatment was started. As his early treatment with parenteral copper-histidine prevented the neurological disorders effectively, prenatal diagnosis is very important.

Human umbilical cord and fetal membranes co-express leptin and its receptor genes

Leptin, protein product of the ob gene, not only regulates food intake and energy expenditure but also has a number of other actions in the body. Leptin actions are mediated by its receptors that have either a long or a truncated intracellular domain, which is coupled to signal transduction pathways. Previous studies have demonstrated that human placenta expresses both leptin and its receptors. However, it is not known whether human umbilical cord and fetal membranes are also sites of expression of these molecules. Therefore, the present study investigated leptin and its receptor expression in these tissues from term pregnancy. Reverse-transcription polymerase chain reaction (RT-PCR) amplified expected size fragments of leptin and also its short and long receptor isoforms from umbilical cord and fetal membranes. The authenticity of PCR-amplified fragments was confirmed by Southern blot hybridization with corresponding cDNA probes. Western blotting revealed that the transcripts were translated into 16-kDa leptin, and 125-kDa (long) and 100-kDa (short) leptin receptor isoforms. However, the long form is present in umbilical cord and the short form in the fetal membranes. Immunocytochemistry revealed that leptin and its receptor isoforms were present in endothelial cells and smooth muscle of umbilical veins and artery, myofibroblasts in Wharton's jelly, amnion covering the cord, amnion and chorion in reflected fetal membranes and decidua from membranes. Amnion, however, contained the highest levels of leptin and its receptor immunostaining. In summary, term pregnancy human umbilical cord and fetal membranes co-express leptin and its receptor genes, which supports the hypothesis that leptin is an autocrine and paracrine regulator in these tissues.

Apoptosis and related proteins during parturition in prostaglandin F receptor-deficient mice

This study investigated whether apoptosis and related proteins are involved in parturition by comparative observation of FP-deficient mice without labor and wild type mice with vaginal delivery. We examined the expression of apoptosis, Fas, FasL, active caspase-3 and bcl-2 proteins in the amnion, placenta and decidua. DNA laddering in the amnion, placenta and decidua tissue did not significantly differ between FP-deficient and wild type mice on day 18 of pregnancy. Similar TUNEL staining results were found in all tissues of FP-deficient mice compared with those of wild type mice. A higher intensity of apoptotic cells was found in the decidua basalis. The index of TUNEL-positive cells were not significantly different in the amnion, placenta and decidua of FP-deficient mice compared with that of wild type mice on day 18 of pregnancy. Specific bands for Fas were clearly observed in the amnion, placenta and decidua tissue. FasL specific bands were observed in the placenta and decidua, but a few in amnion tissue. A great number of active caspase-3 specific bands were detected in decidua, while a few such bands were detected in the placenta and few bands in the amniotic tissue. Bands for bcl-2 were detected in the amnion, placenta and decidua tissue. The weakest band was in decidual tissue. Fas, FasL, active caspase-3, and bcl-2 specific bands did not show any significant differences between the two groups. These findings demonstrate that apoptosis, Fas, FasL, caspase-3, and Bcl-2 occur in mouse term placenta that is not involved in parturition.

Association of type II apoptosis and 92-kDa type IV collagenase expression in human amniochorion in prematurely ruptured membranes with tumor necrosis factor receptor-1 expression

OBJECTIVE

We assessed the presence of tumor necrosis factor receptor-1 (TNF-R1), apoptosis, and simultaneous expression of 92-kDa collagenase type IV (MMP-9) in samples of human chorioamnion from women with premature rupture of membranes (PROM).

METHODS

Amniotic membranes from women who underwent normal labor, cesarean delivery, or had PROM at term were studied by immunohistochemistry for localization of TNF-R1 and R2. Transmission electron microscopy and DNA fragmentation analyses by agarose gel electrophoresis were performed to identify apoptosis characteristics. Zymography and in situ zymography were used to assess gelatinolytic activity.

RESULTS

We found that TNF-R1 was abundant in membranes from subjects who had normal labor and very abundant in those who had PROM. By contrast TNF-R2 was abundant only in membranes from subjects who had cesarean delivery. Gelatinolytic activity was associated with extracellular matrix rather than cells and was higher in extracts from fetal membranes from PROM and normal labor than in extracts obtained from cesarean deliveries. Transmission electron microscopy of fetal membranes from PROM revealed ultrastructural characteristics in amnion epithelium consistent with type II apoptosis. DNA laddering in agarose gel electrophoresis corroborated results from DNA fragmentation.

CONCLUSION

During PROM the fetal membranes undergo type II apoptosis and extracellular matrix degradation in association with TNF-R1 expression.

[Kinetic of beta1-adrenergic reaction of chicken embryo amnion]

Dose-dependent curves of the inhibitory beta 1-adrenergic reaction of the chick embryo amnion were analyzed on the basis of different mathematical models. Selection of the optimal model, closest to the experimental data, allows us to obtain the reaction parameters with the smallest statistical error. Two main characteristics of the physiological reaction, EC50 and Pm, sufficed for the description of the action of agonists nonselective for beta 1-adrenoreceptors: adrenaline (EC50 0.19 +/- 0.02 microM, Pm 101.3 +/- 1.9%) and salbutamol (EC50 0.58 +/- 0.01 microM, Pm 42.7 +/- 0.3%). The Hill coefficient n in these experiments was close to 1 (1.06 +/- 0.14; 0.96 +/- 0.02). It was necessary to introduce fractional values 1 < n < 2 to describe the effects of noradrenaline and isopropyl noradrenaline.

Regions responsible for organizing the microtubular cytoskeletons of extra-embryonic membranes

We have identified putative microtubule-organising centres in whole mounts and frozen sections of full term human placenta, amniochorion and first trimester chorionic villus tissue by indirect immunofluorescence confocal laser scanning microscopy. These sites may perform a crucial executive role in the morphogenesis of human extra-embryonic membranes, and also may establish polarity in the amniotic epithelium and mediate the branching pattern of growth essential to the production of the chorionic villus tree.

Immunocytochemical localization of a caveolin-1 isoform in human term extra-embryonic membranes using confocal laser scanning microscopy: implications for the complexity of the materno-fetal junction

This immunochemical, immunocytochemical, histological and ultrastructural study demonstrates the presence of caveolin 1 in a number of locations in term human extra-embryonic membranes. Strong expression was observed in fetal blood vessel endothelial cells of chorionic villi (cv) and in cv, amniotic and chorionic plate mesenchymal cells, but weak expression was characteristic of trophoblast. Expression in the amniotic epithelium indicated a stronger association with apical as opposed to baso-lateral membranes. Strong immunoreactivity in the thin lining layer of the maternal blood space of the basal plate was a surprising finding. Previously defined as trophoblast, we argue that this is at least partly endothelium based on this new histological, ultrastructural and immunocytochemical data.

Vitamins C and E: missing links in preventing preterm premature rupture of membranes?

We propose that generation of reactive oxygen species may be a potentially reversible pathophysiologic pathway leading to preterm premature rupture of the membranes. Reactive oxygen species generated by the body's response to diverse insults such as infection, cigarette smoking, bleeding, or cocaine use can activate collagenolytic enzymes and impair fetal membrane integrity. Vitamin E, a lipid-soluble antioxidant, inhibits membrane-damaging effects of reactive oxygen species-induced lipid peroxidation. Vitamin C, a water-soluble antioxidant in plasma, stimulates and protects collagen synthesis while recycling vitamin E. Prior evidence shows that (1) damage by reactive oxygen species can impair fetal membrane integrity, (2) reduced midgestation levels of vitamin C are associated with preterm premature rupture of membranes, and (3) these vitamins can be safely and effectively absorbed and delivered to gestational tissues. Current prenatal vitamin preparations contain vitamins C and E in concentrations that are less than 1/3 and 1/10, respectively; these levels have been suggested for effective antioxidant protection. We hypothesize that increased dietary consumption or supplementation of vitamins C and E during pregnancy may reduce physiologically the risks of that portion of preterm premature rupture of membranes that is mediated by excessive or undamped peroxidation of fetal membranes. This hypothesis, if confirmed, should stimulate initiation of therapeutic trials to test the efficacy of enhanced supplementation with vitamins C and E during pregnancy to prevent preterm premature rupture of membranes.

Laminin-5 is a component of preserved amniotic membrane

PURPOSE

To determine if laminin-5 is retained in the matrix of cryopreserved human amniotic membrane tissue prepared for ocular surgeries.

METHODS

Amniotic membrane was solubilized in urea/SDS buffer. Constituent proteins were resolved by SDS-PAGE and laminin-5 content was determined by Western blot analysis using a panel of antibodies directed against the alpha3, beta3 or gamma2 chains of the molecule. Human corneal epithelial cells were seeded on amniotic membrane and cultured in the presence or absence of EGF. The cell-membrane construct was examined for laminin-5 content using Western blot analysis and immunofluorescence microscopy.

RESULTS

In preserved amniotic membrane the laminin-5 alpha3 chain is present in both the unprocessed (190-kDa) and processed (160-kDa) forms. The beta3 chain is found in the 145-kDa form. The gamma2 chain appears to be predominantly in the processed (105-kDa) form. Very little of the unprocessed form of the gamma2 chain (155-kDa) could be detected using immunoblot analysis. A similar distribution of laminin-5 was also present in extracts of corneal epithelial cells cultured on amniotic membrane. Immunofluorescence analysis of cells cultured on the membrane demonstrated polarization of laminin-5 at the cell-membrane interface.

CONCLUSIONS

The presence of both the unprocessed and processed forms of laminin-5 alpha3 and gamma2 chains in preserved human amniotic membrane suggests that when used as a substrate in ocular surgeries, this membrane may be capable of promoting corneal epithelial cell motility and adhesion. Regulation of the motile or adhesive function may lie with factors secreted by the corneal epithelium that populates the membrane following surgery.

Proteoglycans and hyaluronan in human fetal membranes

OBJECTIVE

The aim of this study was to describe the distributions of major extracellular matrix components, such as proteoglycans, collagen and hyaluronan, in the fetal membranes at term.

STUDY DESIGN

Fetal membranes were obtained from elective cesarean deliveries at term. Guanidinium extracts were analyzed for proteoglycans with alcian blue precipitation, sodium dodecyl sulfate- polyacrylamide gel electrophoresis, and Western blotting and for hyaluronan with a radioimmunoassay. Collagen was measured by estimating hydroxyproline content. Tissue sections were immunostained for decorin and biglycan and stained for hyaluronan with a biotin-labeled hyaluronan-binding protein.

RESULTS

The fetal membranes contained predominantly smaller proteoglycans, such as biglycan and decorin. The amnion consisted of typical fibrous connective tissue with a high concentration of collagen. The amnion was dominated by decorin located in close connection with the collagen fibrils. The chorion was composed of a fibroblastic part containing collagen and decorin and a trophoblastic part mainly containing biglycan. In addition, large amounts of hyaluronan were found, especially in the amnion and in the decidual cell layers.

CONCLUSION

The distributions of proteoglycans, collagen, and hyaluronan in human fetal membranes may explain the biomechanical properties of this tissue. We suggest that changes in the relative proportions of these extracellular molecules are crucial for the proposed maturation process in the fetal membranes during the last weeks of pregnancy.

Tissue kallikrein in human placenta in early and late gestation

This study was addressed to identify kallikrein mRNA and protein in early, preterm, and term human placenta and to evaluate their temporospatial pattern. Kallikrein mRNA was expressed in syncytio/cytotrophoblasts and in the endothelial cells of the floating villi, with a greater intensity in early samples (isolated spontaneous abortions and ectopic pregnancies). Cytotrophoblasts at the base of the anchoring villi, maternal decidua and decidual arteries, endothelial cells of chorionic and basal plate blood vessels, and the amniotic epithelium presented a positive signal. Tissue kallikrein was predominantly observed in syncytiotrophoblasts and had a greater immunoreactivity in first-trimester samples. Intraarterial trophoblasts, blood vessels of the floating villi, basal and chorionic plates, and the amniotic epithelium showed positive immunoreactivity. The sites and variations of the tissue kallikrein mRNA and protein in the human placenta, in different stages of pregnancy, support the hypothesis that this enzyme may participate in the establishment and maintenance of placental blood flow through vasodilation, platelet antiaggregation, cell proliferation, and trophoblast invasion.

Change of adrenomedullin concentrations in plasma and amniotic fluid, and human placental adrenomedullin expression with advancing gestation

In order to characterize the expression of adrenomedullin during pregnancy, we measured the mature and total concentrations in maternal plasma and amniotic fluid, and examined its expression in fetoplacental tissues. Plasma samples were obtained from 13 normal normotensive non-pregnant women and 14 normal normotensive post partum women. Maternal plasma and amniotic fluid samples were obtained from 37 normal pregnant women (10 in the first trimester, 13 in the second trimester and 14 in the third trimester). Fetoplacental tissues were obtained from first and third-trimester pregnancies. Mature and total adrenomedullin concentrations in plasma and amniotic fluid were determined by using specific radioimmunoassay. The distribution and expression of adrenomedullin were determined using immunohistochemistry, reverse-transcriptase polymerase chain reaction, and in situ hybridization. Plasma total adrenomedullin concentrations were increasing with advancing gestation. The mature/total adrenomedullin ratio in the second trimester was the highest during pregnancy. Mature and total adrenomedullin concentrations in the amniotic fluid were significantly higher than those in the maternal plasma throughout gestation (P< 0.05). Mature adrenomedullin concentrations and the mature/total adrenomedullin ratio in the amniotic fluid increased with advancing gestation. There was a significant linear correlation between amniotic fluid and maternal plasma mature/total adrenomedullin ratio in the first or second trimester of pregnancy. Adrenomedullin mRNA was identified in the amniotic membrane and chorionic villi, and within the endothelial layers of villous blood vessels. These results suggest that the mature/total adrenomedullin ratio is modified in maternal plasma and amniotic fluid with advancing gestation.

Fetal esophageal ligation induces expression of vascular endothelial growth factor messenger ribonucleic acid in fetal membranes

OBJECTIVE

Obstruction of the fetal esophagus does not always produce the expected polyhydramnios. This is because of increased intramembranous absorption of amniotic fluid into the fetal circulation. A possible mediator for this increased absorption is vascular endothelial growth factor (VEGF). The present objective was to explore whether VEGF gene expression and action would be induced in fetal membranes and placentas of ovine fetuses after esophageal ligation.

STUDY DESIGN

Five late-gestation fetal sheep underwent esophageal ligation and 5 served as control animals. On postoperative day 9, amnion, chorion, and placenta were collected for cellular localization and quantitation of VEGF messenger ribonucleic acid by in situ hybridization and Northern blot analysis. Reverse-transcription polymerase chain reaction was used to identify the VEGF molecular forms. Immunostaining with Ki-67 antibody was used to determine the proliferation of vascular endothelium in the fetal membranes and placentas.

RESULTS

VEGF messenger ribonucleic acid was localized in amniotic epithelium, chorionic cytotrophoblast, and cytotrophoblast of the placenta. VEGF164 was the major transcript expressed in these tissues. The abundance of VEGF messenger ribonucleic acid in the amnion and chorion, but not in the placenta, was significantly increased in the ligated fetuses in comparison with the control fetuses. The proliferation of the intramembranous blood vessel endothelium was greater in the ligated fetuses than in the control fetuses.

CONCLUSION

The levels of VEGF messenger ribonucleic acid and the proliferation of vascular endothelium in the amnion and chorion increased after fetal esophageal ligation. This provides a possible mechanism for the enhanced intramembranous absorption of amniotic fluid through increased vascularity and permeability of the fetal membranes, thus ameliorating the development of polyhydramnios. We speculate that the signal(s) that mediate the increase in VEGF expression is present in either the fetal urine or the fetal lung secretions, or both.

Localization and characterization of urocortin during human pregnancy

Urocortin, a recently identified peptide of the corticotropin releasing hormone (CRH) peptide family, has potent vasodilatory effects in the human fetal placental circulation in vitro, promoting us to hypothesize that urocortin is produced locally to regulate uteroplacental vascular tone during pregnancy. In the present study, we examined the distribution of urocortin in the human placenta, fetal membranes and uterine tissue at term in the presence and absence of labour, using a urocortin antibody produced in our laboratory and the immunoperoxidase staining method. Immunoreactive (IR)-urocortin was observed in the vascular smooth muscle of the myometrium (n=5), decidual stromal cells, syncytiotrophoblast and amnion epithelium (n=10). No differences in staining intensity for urocortin were detected between tissues obtained in the absence (n=5) or presence (n=5) of labour. Staining intensity for IR-urocortin was greatest in the decidua suggesting this may be a site of urocortin production during pregnancy. Subsequently, we tested urocortin secretion from chorio-decidual cells in vitro, using an immunoblot technique. Positive staining for urocortin was observed in 40 per cent of chorio-decidual cells with 34 per cent of these cells secreting urocortin under basal conditions. Since urocortin was secreted by decidual cells we questioned whether urocortin was present in maternal plasma throughout gestation, using radioimmunoassay. Urocortin was detectable in maternal plasma from 7 weeks of gestation and concentrations did not change as gestation progressed. IR-urocortin in the maternal plasma eluted from a Sephadex G-50 column at the same site as synthetic urocortin and had a calculated retention coefficient (Kd) of 0.44. In summary, this study indicates that urocortin is produced by the decidua during human pregnancy and is detectable in maternal plasma. These data are consistent with the hypothesis that urocortin is produced locally by the decidua and may act to regulate uteroplacental blood flow.

The hydroxyproline content of amnion and prelabour rupture of the membranes

OBJECTIVE

To determine whether prelabour rupture of the membranes is caused by a generalised reduction in amniotic collagen.

SETTING

Leeds General Infirmary, UK.

STUDY DESIGN

The hydroxyproline content of amnion from 55 women with prelabour rupture of the membranes was compared with that from 50 women whose membranes ruptured during labour and 28 women who were delivered by elective caesarean section.

RESULTS

No association was found between hydroxyproline content and the timing of membrane rupture. Hydroxyproline content was inversely correlated with gestation. The hydroxyproline content per cm(2) amnion was significantly increased in cases which had laboured. There was a strong correlation between the mechanical properties and the hydroxyproline content of amnion.

CONCLUSIONS

PROM is not associated with a generalised reduction in the hydroxyproline content of amnion.

Preterm fetal growth restriction is associated with increased parathyroid hormone-related protein expression in the fetal membranes

OBJECTIVE

Parathyroid hormone-related protein has roles in normal fetal growth, placental calcium transport, and vascular tone regulation; these factors are compromised in growth-restricted fetuses. Our objective was to determine whether intrauterine parathyroid hormone-related protein expression was increased in association with fetal growth restriction.

STUDY DESIGN

The expression of parathyroid hormone-related protein was examined in intrauterine tissues from women with idiopathic fetal growth restriction with preterm (n = 8-10) and term (n = 8-10) gestations and from gestation-matched control subjects. The abundance and immunoreactive content of parathyroid hormone-related protein messenger ribonucleic acid were determined by Northern blot and radioimmunoassay, respectively, in the placenta, amnion, and chorion-decidua.

RESULTS

The expression of parathyroid hormone-related protein messenger ribonucleic acid was increased in the amnion (placental and reflected) in association with preterm fetal growth restriction (P <.05). Both parathyroid hormone-related protein messenger ribonucleic acid and protein expression were increased in chorion-decidua in association with preterm fetal growth restriction (P <.05). In term gestations both parathyroid hormone-related protein messenger ribonucleic acid and protein expression were greater in amnion over placenta than in reflected amnion (P <.05); these in turn were greater than those in chorion-decidua (P <.05). No significant changes were detected in parathyroid hormone-related protein messenger ribonucleic acid or in protein expression in association with term fetal growth restriction.

CONCLUSION

Either parathyroid hormone-related protein messenger ribonucleic acid or protein expression, or both, was increased in the fetal membranes in association with fetal growth restriction in preterm but not term gestations, suggesting that parathyroid hormone-related protein may be involved in the pathogenesis of preterm fetal growth restriction.

Extra-pituitary growth hormone in peripheral tissues of early chick embryos

Early embryonic growth is independent of pituitary growth hormone (GH), since it occurs prior to the differentiation of pituitary somatotrophs. Embryogenesis is therefore thought to be regulated by local growth factors. As GH is now known to be produced in many extrapituitary sites, in which it acts in an autocrine or paracrine manner, the possibility that extra-pituitary GH may participate in embryogenesis and organogenesis was assessed by determining the immunocytochemical presence and location of GH- and GH-receptor (GHR)-like proteins in the peripheral tissues of chick embryos during their 21-day incubation period. Immunoreactive (IR)-GH, detectable by a monoclonal and two polyclonal antibodies for chicken GH, was specifically and ubiquitously present in tissues of 3-day-old embryos. At embryonic day (ED) 5, IR-GH was widespread in ectodermal, mesodermal and endodermal tissues, but it was not present in every cell of each tissue. IR-GH was particularly abundant i! n the neural tube, notochord, limb bud, somites, heart, stomach, liver, kidney, Wolffian duct and the amnion. By ED8, IR-GH was still widespread and was now present in limb bud cartilage, although the heart and liver were no longer GH immunoreactive. GH receptor immunoreactivity was also present in most tissues and cells of ED3-ED8 embryos. These results demonstrate that extrapituitary GH is abundantly present during early embryogenesis, prior to the differentiation of pituitary somatotrophs (at ED12). Since GH- and GHR-like proteins are present in most tissues of the chick embryo, it is proposed that extrapituitary GH may act as a local growth factor during embryonic development.

Transforming growth factor-beta(1), -beta(2), -beta(3) and their type I and II receptors in human term placenta

Expression of transforming growth factor (TGF)-beta(3) as well as cellular localization of TGF-beta receptors has not been demonstrated in placenta. TGF-beta receptor type I (RI) and type II (RII) are required to transmit TGF-beta signals, therefore the determination of cells expressing both receptors in concert is necessary to identify target cells for TGF-beta. We investigated presence and localization of TGF-betas and their receptors (RI, RII) in human term placenta using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. RT-PCR showed that messenger RNA for TGF-beta(1), -beta(2), -beta(3), and RI and RII is present in human term placenta. We found intense staining for all TGF-beta isoform and receptor proteins in the syncytiotrophoblastic layer, chorionic plate, and in cells of the extravillous trophoblasts using immunohistochemistry. The simultaneous expression of ligands and their receptors support the hypothesis that TGF-beta may play an important role in regulating growth, differentiation, and function of the human placenta.

Immunolocalisation of interleukin-4 and interleukin-4 receptor in placenta and fetal membranes in association with pre-term labour and pre-eclampsia

The aim of this study was to characterise the localisation and staining intensity of immunoreactive (ir) interleukin-4 (IL-4) and IL-4 receptor (IL-4R) in human placenta and fetal membranes in association with pre-term and term labour, and pre-eclampsia. The data obtained in this study establish the presence of irIL-4 and IL-4R in human placenta and fetal membranes obtained from women at 25-41 completed weeks of gestation. IL-4 and IL-4R immunohistochemical staining was principally localised in villous and chorionic trophoblast, and to amnion epithelial cells. The intensity of IL-4 and IL-4R immunohistochemical staining was not significantly affected by labour status at term or pre-term (p > 0. 05), with the exception of IL-4R in the amnion (p < 0.05). In term amnion, IL-4R was only detectable following labour onset. When data were stratified with respect to the presence or absence of pre-eclampsia, no statistical difference in immunohistochemical localisation or staining intensity for either IL-4 or IL-4R could be identified for any of the tissues studied. Co-localisation of IL-4 and IL-4R within gestational tissues may indicate auto- and/or paracrine mechanisms of action for this cytokine. Tissue-specific, labour-associated induction of IL-4R may contribute to the regulation of biological effects of IL-4 within the uteroplacental unit.

Cell type-specific regulation of fetal fibronectin expression in amnion: conservation of glucocorticoid responsiveness in human and nonhuman primates

The appearance of oncofetal fibronectin (FFN) in cervical and vaginal secretions is predictive of human labor. Levels of FFN in amnion increase with the onset of labor in rhesus monkeys. Since glucocorticoid (GC) levels in serum and amniotic fluid increase in association with parturition, we compared GC-mediated regulation of FFN expression in cultures of amnion epithelial cells and fibroblasts isolated from human and baboon amnions. Cells were maintained with and without dexamethasone (DEX), and levels of FFN in the conditioned media were determined by ELISA. We observed that DEX treatment suppressed FFN levels in both human and baboon amnion epithelial cells, whereas it increased FFN levels in amnion fibroblasts. DEX treatment reduced FFN levels in cytotrophoblasts from human placenta and increased FFN levels in placental fibroblasts. Northern blots revealed that DEX reduced levels of fibronectin (FN) mRNA in amnion epithelial cells and cytotrophoblasts, whereas it increased FN mRNA in amnion and placental fibroblasts. We conclude that GC differentially regulates FFN expression in epithelial and mesenchymal cells from amnion and placenta. In addition, this pattern of cell type-specific FFN regulation by GC is conserved in human and nonhuman primates and may be responsible for parturition-dependent changes in FFN expression in gestational tissues.

Identification of antiangiogenic and antiinflammatory proteins in human amniotic membrane

PURPOSE

To identify the potential antiangiogenic and antiinflammatory proteins expressed in human amniotic membrane tissue.

METHODS

Human amniotic epithelial and mesenchymal cells were isolated from human amniotic membranes by sequential trypsin and collagenase digestion. Total RNAs were harvested from freshly obtained human amniotic epithelial and mesenchymal cells. Antiangiogenic and antiinflammatory proteins were detected by the reverse transcriptase-polymerase chain reaction (RT-PCR) technique and further confirmed by DNA sequencing of PCR-amplified transcripts. The distribution of tissue inhibitors of metalloproteinase (TIMPs) were studied further by immunohistochemistry performed on paraffin-embedded amniotic membrane tissue.

RESULTS

RT-PCR results showed that both human amniotic epithelial and mesenchymal cells express interleukin-1 receptor antagonist, all four TIMPs, collagen XVIII, and interleukin-10. Thrombospondin-1 was expressed in all of the epithelial cell specimens and in one out of five mesenchymal cell specimens. Furthermore, immunohistochemistry studies performed on freshly prepared amniotic membrane confirmed that all members of the TIMP family were present in epithelial and mesenchymal cells as well as in the compact layer of the amniotic stroma. In cryopreserved amniotic membranes, positive staining was seen in residual amniotic cells and stroma.

CONCLUSIONS

Human amniotic membrane epithelial and mesenchymal cells express various antiangiogenic and antiinflammatory proteins. Some of those proteins also were found in amniotic membrane stroma. These findings may explain in part the antiangiogenic and antiinflammatory effects of amniotic membrane transplantation.

Prostaglandin endoperoxide H synthase mRNA expression in the fetal membranes correlates with fetal fibronectin concentration in the cervico-vaginal fluids at term: evidence of enzyme induction before the onset of labour

OBJECTIVE

To determine the relationship of prostaglandin endoperoxide H synthase (PGHS) expression in the gestational tissues and fetal fibronectin in cervico-vaginal fluids before the onset of labour at term.

DESIGN

Cross-sectional, observational study.

SAMPLES

Amnion, chorion laeve and decidua were collected from 24 term pregnant women following elective caesarean section. Samples of cervico-vaginal secretions were obtained from the same women immediately before caesarean section.

METHODS

PGHS-1 and PGHS-2 mRNA levels in tissues were determined by specific ribonuclease protection assays. Fetal fibronectin concentrations in the cervico-vaginal fluids were measured by enzyme-linked immunosorbent assay. The abundance of PGHS mRNA was compared between groups of patients with the same mean gestational age but different cervico-vaginal fetal fibronectin levels. Linear regression analysis was used to determine the association between PGHS levels and fetal fibronectin.

RESULTS

Two groups of women were identified who had significantly different fetal fibronectin values but the same gestational ages. The group with the higher fetal fibronectin concentrations had significantly higher PGHS- 1 and PGHS-2 mRNA levels in the chorion laeve and higher PGHS-2 mRNA levels in the amnion, than the group with lower fetal fibronectin concentrations. PGHS- 1 and PGHS-2 mRNA levels in the chorion laeve and PGHS-2 mRNA in the amnion showed an overall significant association with fetal fibronectin levels.

CONCLUSIONS

High concentrations of fetal fibronectin in cervico-vaginal secretions before the onset of spontaneous labour at term are associated with high levels of PGHS-2 mRNA in the chorion laeve and the amnion and of PGHS- 1 mRNA in the chorion laeve. Increased expression of PGHS in these tissues may therefore be involved in the events leading to term birth.