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Mercer BM, Abdelrahim A, Moore RM, Novak J, Kumar D, Mansour JM, Perez-Fournier M, Milluzzi CJ, Moore JJ. The impact of vitamin C supplementation in pregnancy and in vitro upon fetal membrane strength and remodeling. Reprod Sci 2010; 17:685-95. [PMID: 20581351 PMCID: PMC2930608 DOI: 10.1177/1933719110368870] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Generation of reactive oxygen species (ROS) has been suggested as a mechanism of fetal membrane (FM) weakening leading to rupture, particularly with preterm premature rupture of the fetal membranes (PROM). In vitro, FM incubation with tumor necrosis factor (TNF) mimics physiological FM weakening, concomitant with generation of ROS and collagen remodeling. Proinflammatory cytokines are also postulated to have a role in the development of the FM physiological weak zone where rupture normally initiates in-term gestations. We hypothesized that antioxidant treatment may block ROS development and resultant FM weakening. Two studies examining antioxidant effects upon FM strength were conducted, one in vivo and the other in vitro. Fetal membrane of patients enrolled in a multicenter placebo-controlled trial to determine the effect of vitamin C (1 g/day) and vitamin E (400 IU/day) upon complications of pre-eclampsia were examined for FM biomechanical properties and biochemical remodeling at birth. Separately, biomechanics and biochemical markers of remodeling were determined in FM fragments incubated with TNF with or without vitamin C preincubation. Supplemental dietary vitamin C in combination with vitamin E did not modify rupture strength, work to rupture, or matrix metalloproteinase-9 (MMP9; protein or activity) either within or outside the term FM physiological weak zone. In vitro, TNF decreased FM rupture strength by 50% while increasing MMP9 protein. Vitamin C did not inhibit these TNF-induced effects. Vitamin C alone had a weakening effect on FM in vitro. We speculate that vitamin C supplementation during pregnancy will not be useful in the prevention of preterm PROM.
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Affiliation(s)
- Brian M Mercer
- From the Department of Reproductive Biology, Case Western Reserve University, Cleveland, OH 44109, USA.
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Strohl A, Kumar D, Novince R, Shaniuk P, Smith J, Bryant K, Moore RM, Novak J, Stetzer B, Mercer BM, Mansour JM, Moore JJ. Decreased adherence and spontaneous separation of fetal membrane layers--amnion and choriodecidua--a possible part of the normal weakening process. Placenta 2009; 31:18-24. [PMID: 19922998 DOI: 10.1016/j.placenta.2009.10.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 10/26/2009] [Accepted: 10/27/2009] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The fetal membrane (FM) layers, amnion and choriodecidua, are frequently noted to have varying degrees of separation following delivery. FM layers normally separate prior to rupture during in vitro biomechanical testing. We hypothesized that the adherence between amnion and choriodecidua decreases prior to delivery resulting in separation of the FM layers and facilitating FM rupture. METHODS FM from 232 consecutively delivered patients were examined to determine the extent of spontaneous separation of the FM layers at delivery. Percent separation was determined by the weight of separated FM tissue divided by the total FM weight. Separately, the adherence between intact FM layers was determined. FM adherence was tested following term vaginal delivery (13), term unlabored cesarean section (10), and preterm delivery (6). RESULTS Subjects enrolled in the two studies had similar demographic and clinical characteristics. FM separation was present in 92.1% of membranes. Only 4.3% of FM delivered following spontaneous rupture of the fetal membranes (SROM) had no detectable separation. 64.7% of FM had greater than 10% separation. FM from term vaginal deliveries had significantly more separation and were less adherent than FM of term unlabored, elective cesarean section (39.0+/-34.4% vs 22.5+/-30.9%, p=.046 and 0.041+/-0.018N/cm vs 0.048+/-0.019N/cm, p<.005). Preterm FM had less separation and were more adherent than term FM (9.95+/-17.7% vs 37.5+/-34.4% and 0.070+/-0.040N/cm vs 0.044+/-0.020N/cm; both p<.001). CONCLUSIONS Separation of the amnion from choriodecidua at delivery is almost universal. Increased separation is associated with decreased adherence as measured in vitro. Increased separation and decreased adherence are seen both with increasing gestation and with labor suggesting both biochemical and mechanical etiologies. The data are consistent with the hypothesis that FM layer separation is part of the FM weakening process during normal parturition.
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Affiliation(s)
- A Strohl
- Departments of Pediatrics, Case Western Reserve University (CWRU), MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH, USA
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Kumar D, Novince R, Strohl A, Mercer BM, Mansour JM, Moore RM, Moore JJ. A new methodology to measure strength of adherence of the fetal membrane components, amnion and the choriodecidua. Placenta 2009; 30:560-3. [PMID: 19410292 DOI: 10.1016/j.placenta.2009.03.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 03/25/2009] [Accepted: 03/27/2009] [Indexed: 11/25/2022]
Abstract
We have previously shown that separation of the amnion from choriodecidua occurs as an integral part of the fetal membranes (FM) rupture process. We have also reported that spontaneous separation of FM is nearly universal with term vaginal delivery. The etiology of this spontaneous FM separation is unknown. If biochemical degradation at the amnion-choriodecidua interface is a factor, decreased adhesive force between the FM components prior to their complete separation would be expected. The purpose of this project was to develop and validate machinery and procedures to measure the adhesive force between amnion and choriodecidua. Commercial tensile testing equipment was adapted to perform a standard T-peel test, per the American Society for Testing and Materials (ASTM) guidelines. FM test strip dimensions, peel speed, and peel force data measurements from force versus displacement curves were optimized for reproducibility. Test system validation was performed using Shurtape CP 60 (slow release painter's masking tape) as the standard. Equipment and procedures for a standard T-peel test on FM were developed. Shurtape CP 60 of decreasing widths showed reproducible, linear changes in the adhesive force range for FM (r(2)=0.96). The adhesive force between FM components ranged from 0.017 to 0.262 N/cm. Reproducibility was optimal with FM test strips of 4 x 6 cm and a peel speed of 25.4 cm/min. FM showed greater adhesive force adjacent to the placental disc than distal from the disc (p<0.05). We have developed equipment and procedures to accurately and reproducibly measure adhesive force between the FM amnion and choriodecidua.
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Affiliation(s)
- D Kumar
- Department of Pediatrics, Case Western Reserve University (CWRU), MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109, USA
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Joyce EM, Moore JJ, Sacks MS. Biomechanics of the fetal membrane prior to mechanical failure: review and implications. Eur J Obstet Gynecol Reprod Biol 2009; 144 Suppl 1:S121-7. [PMID: 19303191 DOI: 10.1016/j.ejogrb.2009.02.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Annually, premature birth is a major public health problem accounting for over 13,000 deaths and 30,000 surviving infants with life-long morbidity. Preterm premature rupture of the membranes is the initiating event leading to preterm birth of 40% of these premature infants. Fetal membrane (FM) rupture is a catastrophic tissue failure, a unique event in normal physiology; other tissue failures (bone breaks, aneurism ruptures) are pathological processes. The mechanisms which cause FM failure and thereby rupture are not understood. A full understanding of FM failure process requires a complete characterization of structural and biomechanical behavior at near/full term under sub-failure (forces well below that which induce rupture) and failure conditions as well as elucidating the biological factors which modulate its failure. The relatively, highly loaded state of the FM in vivo may also facilitate its susceptibility to enzymatic degradation, which was shown to be augmented with increased load in collagenous tissues. Indeed, this last observation may help to provide the link between biomechanical degradation and premature mechanical failure in the FM. This integrated approach will further the understanding of this unique physiological event and thereby provide insight into how to anticipate and when appropriate, intervene to prevent preterm FM rupture.
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Affiliation(s)
- Erinn M Joyce
- The Swanson School of Engineering, Department of Bioengineering, and the McGowan Institute, University of Pittsburgh, Pittsburgh, PA 15219, USA
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Differential expression of fibulin family proteins in the para-cervical weak zone and other areas of human fetal membranes. Placenta 2009; 30:335-41. [PMID: 19230968 DOI: 10.1016/j.placenta.2009.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 01/19/2009] [Accepted: 01/21/2009] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Human fetal membranes (FM) at term have been shown to contain a weak zone in the region overlying the cervix which exhibits characteristics of increased collagen remodeling and apoptosis. It has been hypothesized that the FM rupture initiation site is within this weak zone. Although the FM weak zone has been partially characterized, it is unclear what structural differences in the extracellular matrix result in its decreased rupture strength. A screen for differentially expressed proteins in the amnion of the weak zone versus other FM areas demonstrated that fibulin 1 was decreased. We investigated potential regional differences in all fibulin protein family members. METHODS FM fibulins were localized by immunohistochemistry. Detected fibulins were screened by Western blot for differences in abundance in the amnion of the weak zone versus non-weak zone FM regions. Amnion epithelial and mesenchymal cells were also screened for fibulin production. RESULTS Fibulins 1 and 5 were detected in the cytoplasm of and in a pericellular pattern surrounding all FM cells, and in a dense extracellular pattern in the amniotic compact zone. Fibulin 3 was detected within the cytoplasm of amnion epithelial and chorion trophoblast cells. Fibulins 2 and 4 were not detected. Fibulins 1, 3 and 5 demonstrated decreased abundance of 33%, 63% and 58% (all P<0.01) in amnion of the weak zone relative to other FM regions. Amnion cells produced all three detected fibulins. Furthermore, TNF inhibited amnion cell fibulin production in a dose dependent manner. CONCLUSION Fibulins 1, 3 and 5 were localized coincident with major microfibrillar networks in amnion. Each showed decreased abundance in the amnion component of the FM weak zone. Amnion epithelial and mesenchymal cells produced all three fibulins and their abundance was inhibited by TNF. We speculate that the amnion microfibrillar layer undergoes significant remodeling with the development of the FM weak zone.
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Moore RM, Novak JB, Kumar D, Mansour JM, Mercer BM, Moore JJ. Alpha-lipoic acid inhibits tumor necrosis factor-induced remodeling and weakening of human fetal membranes. Biol Reprod 2008; 80:781-7. [PMID: 19109223 DOI: 10.1095/biolreprod.108.073205] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Untimely rupture of the fetal membranes (FMs) is a major precipitant of preterm birth. Although the mechanism of FM weakening leading to rupture is not completely understood, proinflammatory cytokines, including tumor necrosis factor (TNF) and interleukin 1 beta (IL1B), have been shown to weaken FMs concomitant with the induction of reactive oxygen species, collagen remodeling, and prostaglandin release. We hypothesized that alpha-lipoic acid, a dietary antioxidant, may block the effect of inflammatory mediators and thereby inhibit FM weakening. Full-thickness FM fragments were incubated with control media or TNF, with or without alpha-lipoic acid pretreatment. Fetal membrane rupture strength and the release of matrix metalloproteinase 9 (MMP9) and prostaglandin E(2) (PGE(2)) from the full-thickness FM fragments were determined. The two constituent cell populations in amnion, the mechanically strongest FM component, were similarly examined. Amnion epithelial and mesenchymal cells were treated with TNF or IL1B, with or without alpha-lipoic acid pretreatment. MMP9 and PGE(2) were analyzed by ELISA, Western blot, and zymography. TNF decreased FM rupture strength 50% while increasing MMP9 and PGE(2) release. Lipoic acid inhibited these TNF-induced effects. Lipoic acid pretreatment also inhibited TNF- and IL1B-induced increases in MMP9 protein activity and release in amnion epithelial cells, as well as PGE(2) increases in both amnion epithelial and mesenchymal cells. In summary, lipoic acid pretreatment inhibited TNF-induced weakening of FM and cytokine-induced MMP9 and PGE(2) in both intact FM and amnion cells. We speculate that dietary supplementation with alpha-lipoic acid might prove clinically useful in prevention of preterm premature rupture of fetal membranes.
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Affiliation(s)
- Robert M Moore
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio 44109, USA
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Pasquier JC, Doret M. [Fetal membranes: embryological development, structure and the physiopathology of the preterm premature rupture of membranes]. ACTA ACUST UNITED AC 2008; 37:579-88. [PMID: 18424017 DOI: 10.1016/j.jgyn.2007.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 07/13/2007] [Accepted: 12/06/2007] [Indexed: 12/17/2022]
Abstract
Fetal membranes development is a complex process. The amniotic and exo-celomic cavities are appearing first. The rapid growth of the amniotic cavity is leading to the disappearance of the exo-celomic cavity and the chorion is merging with the decidua. Fetal membranes consist of three layers: the amnion and the chorion, issued from fetal tissues and the decidua issued from maternal tissue. A balance between the synthesis and the degradation of membranes components is physiologic throughout the gestation. Two main mechanisms are involved in the degradation process: apoptosis in the cellular compartment and matrix metalloproteinase (MMP) in the extracellular matrix. Regulation of MMP is depending on factors increasing their expression (cytokines) and factors decreasing their activity tissue inhibitor of metalloproteinases (TIMPS). Particular conditions can induce an unbalance between synthesis and degradation leading to the weakening of the membranes. Different factors can be associated to induce this unbalance: infection, hormonal factors, default in membranes fusion, oxidative stress and mechanic factors. In fine, the spontaneous rupture of the membranes is always occurring in regard of the uterine cervix after a process started several weeks before.
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Affiliation(s)
- J-C Pasquier
- Département de gynécologie-obstétrique, faculté de médecine, université de Sherbrooke, Sherbrooke Qc 3001, J1H 5N4 Canada.
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Han YM, Romero R, Kim JS, Tarca AL, Kim SK, Draghici S, Kusanovic JP, Gotsch F, Mittal P, Hassan SS, Kim CJ. Region-specific gene expression profiling: novel evidence for biological heterogeneity of the human amnion. Biol Reprod 2008; 79:954-61. [PMID: 18685129 DOI: 10.1095/biolreprod.108.069260] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The amnion plays an important role during pregnancy and parturition. Though referred to as a single structure, this fetal tissue is regionally divided into placental amnion, reflected amnion, and umbilical amnion. Histological differences between placental amnion and reflected amnion led us to hypothesize that the amnion is biologically heterogeneous. The gene expression profiles of placental amnion and reflected amnion were compared in patients at term with no labor (TNL; n = 10) and in labor (TIL; n = 10). Real-time quantitative RT-PCR revealed a higher expression of IL1B mRNA in reflected amnion than in placental amnion in TNL cases but not in TIL cases. Extended screening using microarrays showed differential expression of 17 genes in labor, regardless of the region. Interestingly, 839 genes were differentially expressed between placental amnion and reflected amnion. Pathway analysis identified 19 signaling pathways, such as mitogen-activated protein kinase and transforming growth factor beta pathways, associated with region. Lipopolysaccharide (LPS) treatment of the amnion explants showed more robust activation of mitogen-activated protein kinase 3/1 (extracellular signal-regulated kinase 1/2) in placental amnion of TNL but not in TIL cases. Placental amnion from TNL and TIL cases showed a significant difference in the amplitude of IL1B mRNA induction by LPS. We report that the anatomical region has a substantial impact on the transcriptional program and the biological properties of the amnion. Labor-associated switching to a proinflammatory signature is a feature particular to placental amnion. The novel observations herein strongly suggest that the seemingly homogeneous amnion is biologically heterogeneous and compartmentalized, with implications for the physiology of pregnancy and parturition.
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Affiliation(s)
- Yu Mi Han
- Perinatology Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892, USA
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Kendal-Wright CE, Hubbard D, Bryant-Greenwood GD. Chronic stretching of amniotic epithelial cells increases pre-B cell colony-enhancing factor (PBEF/visfatin) expression and protects them from apoptosis. Placenta 2008; 29:255-65. [PMID: 18272217 DOI: 10.1016/j.placenta.2007.12.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 12/21/2007] [Accepted: 12/24/2007] [Indexed: 01/07/2023]
Abstract
In normal pregnancy, the fetal membranes become increasingly distended towards term and in multifetal gestations they become over-distended. Apoptosis of the amniotic epithelium increases with advancing gestation and may contribute to fetal membrane weakening and rupture. The effects of chronic static stretching for 36h have been investigated using primary amniotic epithelial cells. Pre-B cell colony-enhancing factor (PBEF) is a stretch-responsive cytokine and expression of its gene, intracellular and secreted protein were all significantly increased by 4h and its secretion sustained over 36h, contrasting with the rapid increase and decline in expression of IL-8. Increased expression of SIRT1 and decreased p53 paralleled the changes in PBEF, are known to be responsive to PBEF, and contribute to cell survival. Distension had no effects on proliferation or necrosis but protected the cells from apoptosis, knocking-down PBEF with antisense probes abrogated this protective effect. There was increased immunostaining of PBEF in the compact layer of the amnion in multifetal tissues and significantly fewer apoptotic amniotic epithelial cells. These results show that chronic stretching of the amniotic epithelial cells increases PBEF expression, which protects them from apoptosis.
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Affiliation(s)
- C E Kendal-Wright
- Developmental and Reproductive Biology, John A Burns School of Medicine, Honolulu, HI 96813, USA.
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Calvin SE, Oyen ML. Microstructure and mechanics of the chorioamnion membrane with an emphasis on fracture properties. Ann N Y Acad Sci 2007; 1101:166-85. [PMID: 17332077 DOI: 10.1196/annals.1389.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The normal mechanical functioning of an intact chorioamnion (CA) membrane is essential to successful human reproduction. The amnion and the chorion, separately and together as the bilayer chorioamnion, serve barrier and container functions throughout gestation, and these two important roles are required from conception to birth. The event associated with the "breaking of waters" is a landmark event in labor and delivery. Mechanical rupture of the CA membrane is part of the natural sequence of term delivery, but has serious implications when rupture occurs prior to term; preterm premature rupture of the CA membrane (PPROM) is associated with one-third of premature births. The current manuscript reviews PPROM from a clinical, anatomical, and mechanical perspective with a special focus on the clinically relevant fracture properties of these membranes. Emphasis is given to the link between membrane structure and properties at macroscopic and microscopic length scales. Because it has been demonstrated that the mechanical properties of prematurely failed membranes are not different from membranes of the same gestational age that have remained intact, membrane failure is a local process that must be explored in terms of local changes in structure and properties of isolated portions of the membrane. Future diagnostic techniques aimed at detection of changes in membrane structure (including thickness) and altered mechanical stiffness or strength may allow for prefailure diagnosis of membrane weak spots, thus opening the door for potential intervention and treatment techniques for preterm membrane rupture.
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Affiliation(s)
- Steven E Calvin
- Minnesota Perinatal Physicians--Allina Health System, Minneapolis, Minnesota, USA
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Pandey V, Jaremko K, Moore RM, Mercer BM, Stetzer B, Kumar D, Fox JM, Mansour JM, Moore JJ. The force required to rupture fetal membranes paradoxically increases with acute in vitro repeated stretching. Am J Obstet Gynecol 2007; 196:165.e1-7. [PMID: 17306666 DOI: 10.1016/j.ajog.2006.10.861] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 09/05/2006] [Accepted: 10/06/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The purpose of this study was to determine whether acute repetitive stretching causes fetal membranes (FM) weakening. STUDY DESIGN Cesarean or vaginally delivered FM were repeatedly stretched and thereafter subjected to rupture testing. Rupture strength (RS), work to rupture (WR), and stiffness were determined. Unstretched FM were compared with stretched FM. RESULTS In the cesarean group, FM stretched to 50% or 75% of the baseline (unstretched) RS for 10-20 cycles of 10 seconds each paradoxically showed increased RS and stiffness. WR decreased compared with baseline. Detailed analysis revealed that even a single stretch cycle initiated these changes to physical properties. Vaginally delivered FM showed similar changes in physical properties, as did separated amnion. CONCLUSION Acute stretch forces do not directly cause FM weakening.
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Affiliation(s)
- Vishal Pandey
- Department of Pediatrics, MetroHealth Medical Center, Cleveland, OH 44109, USA
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Labour induces increased concentrations of biglycan and hyaluronan in human fetal membranes. Placenta 2006; 28:482-6. [PMID: 17125833 DOI: 10.1016/j.placenta.2006.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 09/12/2006] [Accepted: 09/19/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The proteoglycan decorin stabilizes collagen whereas biglycan and hyaluronan disrupt well-organized collagen. The aim was to compare hyaluronan and proteoglycans in human fetal membranes obtained before and after spontaneous labour at term. STUDY DESIGN Prelabour samples of fetal membranes (N=9) were obtained from elective caesarean sections and regionally sampled from over the cervix (cervical membranes) and mid-zone samples between this area and the placental edge. Postlabour samples (N=11) were obtained from spontaneous vaginal delivery and also regionally sampled. Amnion and chorio-decidua were analysed separately. The proteoglycans decorin and biglycan were analysed using alcian blue precipitation, SDS polyacrylamide gel electrophoresis and immunostaining. Hyaluronan was analysed using a radioimmunoassay and by histochemistry. Collagen was measured by estimating hydroxyproline content. RESULTS In prelabour membranes the biglycan concentration (microg/mg wtw) in the cervical amnion was 40% lower than in the mid-zone amnion (P<0.05). After delivery the cervical amnion showed a twofold increase in biglycan (P<0.05), a 30% decrease in collagen (P<0.05), and a 50% decrease in decorin concentration (P<0.05). In mid-zone samples after delivery the concentrations of hyaluronan showed an increase form 1.0 to 4.9 microg/mg wtw (P<0.05). Histology demonstrated a gelatinous substance, which separated amnion and chorio-decidua, in particular at the cervical site. This gelatinous substance contained hyaluronan at a concentration of 3.0 microg/mg wtw. CONCLUSION It is well established that prelabour fetal membranes are considerably stronger than postlabour fetal membranes. Two features may explain this; a weakening of the amnion combined with a separation of amnion and chorio-decidua. The biomechanical changes are consistent with the decrease in collagen and decorin, and the increase in hyaluronan and biglycan demonstrated in this study. The separation of the membranes is caused by the formation of a gelatinous substance, rich in hyaluronan. The results indicate that the biomechanical changes are not merely secondary to the stress of labour but that an active maturation process is involved.
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El Khwad M, Pandey V, Stetzer B, Mercer BM, Kumar D, Moore RM, Fox J, Redline RW, Mansour JM, Moore JJ. Fetal membranes from term vaginal deliveries have a zone of weakness exhibiting characteristics of apoptosis and remodeling. ACTA ACUST UNITED AC 2006; 13:191-5. [PMID: 16638590 DOI: 10.1016/j.jsgi.2005.12.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Indexed: 11/17/2022]
Abstract
BACKGROUND Recently we identified a weak zone in term, pre-labor (repeat Cesarean section) human fetal membranes (FM) overlying the cervix with biochemical characteristics suggestive of apoptosis and collagen remodeling. We suggested that this weak zone is the FM rupture initiation site. Vaginally delivered patients have a weak zone in their FM overlying the cervix; a comparable weak zone lies adjacent to the tear line in FM after spontaneous rupture (SROM). METHODS FM from vaginally delivered patients with artificial rupture (AROM) and SROM were collected. FM of AROM patients were marked per vagina to identify the FM zone overlying the cervix. Postpartum FM were cut, strength tested, and piece strengths were remapped to their former location on a three-dimensional model. A 10-cm diameter zone centered on the marked area (AROM), or defined weak zone (SROM) was compared with the remaining FM. RESULTS AROM FM exhibit a para-cervical weak zone. SROM FM exhibit a comparable zone on the tear line. The mean rupture strength within weak zones was 60% of the remaining membranes (P <.001). AROM and SROM FM weak zones both exhibit increased matrix metalloproteinase 9, increased poly (ADP-ribose) polymerase I cleavage, decreased tissue inhibitor of metalloproteinase 3 protein, and histology consistent with remodeling and apoptosis. CONCLUSION Vaginally delivered AROM FM contain a weak zone overlying the cervix. Vaginally delivered SROM FM contain a weak zone adjacent to the tear line that exhibits biochemical and mechanical characteristics suggestive of collagen remodeling and apoptosis comparable to those of the AR FM weak zone.
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Affiliation(s)
- Mohammed El Khwad
- Department of Pediatrics, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
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