Placenta.
Publisher:
W.B. Saunders.. Amsterdam : Elsevier (2010)
Frequency: Ten no. a year, 2001-
Country: Netherlands
Language: English
Start Year:1980 -
ISSN:
0143-4004 (Print)
1532-3102 (Electronic)
0143-4004 (Linking)
1532-3102 (Electronic)
0143-4004 (Linking)
Impact Factor
3.8
2022
| NLM ID: | 8006349 |
| (DNLM): | P16125000(s) |
| (OCoLC): | 05312765 |
| Coden: | PLACDF |
| LCCN: | 80647588 |
| Classification: | W1 PL101C |
Equine hydrallantois is associated with impaired angiogenesis in the placenta. Hydrallantois is the excessive accumulation of fluid in the allantoic cavities during the last trimester of pregnancy, leading to abdominal wall hernias, cardiovascular shock, abortion, and dystocia. It has been postulated that hydrallantois is associated with structural and/or functional changes in the chorioallantoic membrane. In the present study, we hypothesized that angiogenesis is impaired in the hydrallantoic placenta. Capillary density in the hydrallantoic placenta was evaluated in the chorioallantois via immunohistochemistry for Von Willebrand Factor. Moreover, the expression of angio...
Alterations in T cell-related transcripts at the feto-maternal interface throughout equine gestation. The tolerance of pregnancy by the maternal immune system is balanced between recognition and protection. In the human this is controlled by balancing helper T cell populations (Th1, Th2) in addition to immune suppression from the regulatory arm (Tregs), but this has not been evaluated in the horse. RNA sequencing was performed on chorioallantois and endometrium of mares at 120, 180, 300 and 330 days of gestation (n = 4/stage), as well as 45-day chorioallantois (n = 4) and diestrus endometrium (n = 3). Transcripts were selected for relativity to Th1, Th2, or Treg-associated. qPCR an...
The immunolocalization of Galectin-1 and Progesterone-Induced Blocking Factor (PIBF) in equine trophoblast: Possible roles in trophoblast invasion and the immunological protection of pregnancy. The proteins galectin-1 and Progesterone Induced Blocking Factor (PIBF) are present on human and murine trophoblast and are thought to influence both immunomodulation and trophoblast invasion. In equids, the invasive component of the placenta, the endometrial cups, stimulate maternal cell-mediated and humoral immune responses. It was therefore of interest to know if galectin-1 or PIBF could be immunolocalised to the invasive and/or non-invasive components of the equine placenta. Horse and mule (♀ horse X ♂ donkey) embryos and placental tissues between Days 12 and 124 of gestation were stai...
Major histocompatibility complex class I in the horse (Equus caballus) placenta during pregnancy and parturition. Major histocompatibility protein class I (MHC-I) is believed to be expressed in the horse allantochorion only in limited areas at limited times. However, its expression has only been investigated in early pregnancy with non-quantitative techniques that cannot reliably detect small amounts of protein. To quantify the relative expression of MHC-I in the allantochorion and endometrium during days 90-240 of pregnancy (PREG), parturition with physiological delivery of fetal membranes (PHYS), and parturition with retention of these membranes (FMR). Also, to visualize protein expression and determine...
Expression of glucose transporters in the endometrium and early conceptus membranes of the horse. Glucose is the primary energy substrate for early conceptus development and, for the first 40 days of gestation, the equine conceptus depends solely on glucose available in the histotroph; thereafter, histotrophic glucose provision continues to support transport across the definitive placenta. To investigate glucose provision routes during early equine pregnancy we examined expression of glucose transporters in conceptus membranes and endometrium recovered on days 7, 14, 21 and 28 after ovulation. To further differentiate the contributions of maternal progesterone priming and conceptus-endomet...
The proteome of fetal fluids in mares with experimentally-induced placentitis. Placental inflammation (placentitis) is one of the leading causes of late-term abortion in mares. Although prognosis is good assuming early diagnosis and treatment, diagnostics are limited. To better characterize the disease and identify potential biomarkers, we analyzed the proteome of fetal fluids (amniotic and allantoic) in both control mares (n = 5) and mares with experimentally-induced placentitis (n = 5) using LTQ-Orbitrap mass-spectrometry. Placentitis was induced via trans-cervical inoculation of Streptococcus equi ssp. zooepidemicus. In total, 130 proteins were identified in e...
Placental function and structure at term is altered in broodmares fed with cereals from mid-gestation. Feeding pregnant broodmares with cereal concentrates has been shown to increase maternal insulin resistance and affect foal metabolism in the short and long-term. These effects are likely to be mediated by the placenta. Here, we investigated feto-placental biometry and placental structure and function at term in mares fed with or without cereals concentrates. From 7 months of gestation, 22 multiparous mares were fed forage only (group F (n = 12)) or received forage and cracked barley (group B (n = 10)) until foaling. Foals and placentas were weighed and placental samples were collected...
A lectin histochemical study to detect variation in glycosylation at the feto-maternal interface in three interbreeding equine species. In this study, we compare glycosylation at the fetomaternal interface in 3 equine species: horse, donkey and zebra, all of which can interbreed to produce hybrids, to assess their glycan similarities and differences. Methods: Sections cut from 3 specimens of horse (Equus caballus) placenta (50, 200 and 280 days gestation), one donkey (Equus asinus) placenta (65 cm crown-rump length) and 5 specimens of zebra (Equus quagga) placentae (81-239 days gestation) were stained with a panel of 24 biotinylated lectins using an avidin-peroxidase revealing system. Results: There were only slight quantitat...
Negative uterine asynchrony retards early equine conceptus development and upregulation of placental imprinted genes. Placental imprinted genes appear to be sensitive indicators of an inappropriate pre-implantation environment. This study examined the effects of negative uterine asynchrony after embryo transfer (ET) on early horse embryo development, and yolk-sac membrane expression of DNA methyltransferases (DNMTs) and equine specific placental imprinted genes. Methods: Day 8 embryos were transferred to recipient mares on day 8 (synchronous) or day 3 (asynchronous) after ovulation, and conceptuses were recovered 6 or 11 days later (day 14 or 19 of development). Results: Day 14 conceptuses recovered from an a...
Localisation of epidermal growth factor (EGF), its specific receptor (EGF-R) and aromatase at the materno-fetal interface during placentation in the pregnant mare. Implantation and placentation in the mare does not commence until as late as day 40 after ovulation. The reasons for this and the growth factors and/or hormones which drive placentation when it does finally occur are of considerable academic and practical interest. Placental interface tissues recovered from 11 accurately aged and perfused-fixed horse uteri between 20 and 68 days of gestation were stained immunocytochemically for Epidermal Growth Factor (EGF), its specific receptor (EGF-R) and for the steroid hormone enzyme, aromatase. EGF was present in endometrial gland and lumenal epithelia ...
A method for isolating and culturing placental cells from failed early equine pregnancies. Early pregnancy loss occurs in 6-10% of equine pregnancies making it the main cause of reproductive wastage. Despite this, reasons for the losses are known in only 16% of cases. Lack of viable conceptus material has inhibited investigations of many potential genetic and pathological causes. We present a method for isolating and culturing placental cells from failed early equine pregnancies. Trophoblast cells from 18/30 (60%) failed equine pregnancies of gestational ages 14-65 days were successfully cultured in three different media, with the greatest growth achieved for cells cultured in Amnio...
Differences in extracellular matrix remodeling in the placenta of mares that retain fetal membranes and mares that deliver fetal membranes physiologically. In mammals, placenta separation at term may involve degradation of the extracellular matrix by matrix metalloproteinases (MMPs). The activity of MMPs is modulated by TIMPs. We hypothesized that the placentas of mares that deliver fetal membranes physiologically and those that retain fetal membranes (FMR) differ in terms of histology; mRNA expression of MMP-2 and MMP-9; protein expression of MMP-2, MMP-9, and TIMP-2; and the potential activity of both MMPs. Methods: Placenta biopsies were taken from mares (n = 9; 4 FMR, 5 controls) immediately after foal expulsion. Retention was defined as fail...
Absence of maternal cell contamination in mesenchymal stromal cell cultures derived from equine umbilical cord tissue. This study aimed to determine whether maternal cell contamination exists in cells derived from equine umbilical cord tissue, a perspective material for cell-based therapies in veterinary medicine. Potential maternal cell contamination was analyzed at DNA level via a set of 16 microsatellite markers in cells originating from the cord tissue of 22 foals. In these cells no maternal cell contamination was detected at a sensitivity level of 0.01%. Our results suggest that equine umbilical cord tissue-derived cells are entirely of fetal origin.
Molecular evidence for natural killer-like cells in equine endometrial cups. To identify equine orthologs of major NK cell marker genes and utilize them to determine whether NK cells are present among the dense infiltration of lymphocytes that surround the endometrial cup structures of the horse placenta during early pregnancy. Methods: PCR primers were developed to detect the equine orthologs of NKP46, CD16, CD56, and CD94; gene expression was detected in RNA isolated from lymphocytes using standard 2-step reverse transcriptase (RT) PCR and products were cloned and sequenced. Absolute real-time RT-PCR was used to quantitate gene expression in total, CD3+, and CD3- per...
A review of implantation and early placentation in the mare. Constant, self induced mobility throughout the uterine lumen between days 6 and 17 after ovulation, complete envelopment by a self-secreted glycoprotein capsule between days 7 and 30 and 'injection' of specialised, gonadotrophin-secreting trophoblast cells into the maternal endometrium at days 35-37 are three unusual aspects of equine embryogenesis. The outer trophoblast layer of the allantochorion finally establishes a stable, microvillous contact with the lumenal epithelium of the endometrium around days 40-42 and placentation commences thereafter. The allantochorion elongates steadily until...
What fossils can tell us about the evolution of viviparity and placentation. Recently a fossil of one of the earliest jawed fishes was found with a fetal skeleton and the remains of a cord. It was from the Devonian period and takes the history of vertebrate placentation back to 380 million years ago. This and later fossil evidence for viviparity in marine reptiles and early mammals is reviewed. Of particular interest are the fossils of horses as they document that a reproductive strategy with a single precocial newborn was evolved early on. In one instance there is sufficient representation of soft tissue to imply that early horses had a diffuse placenta, much as had b...
Modeling trophoblast differentiation using equine chorionic girdle vesicles. The chorionic girdle of the equine conceptus is comprised of specialized trophoblast cells which, at day 36-38 of equine pregnancy, gain an invasive phenotype and invade the endometrium to form endometrial cups. Studies of equine endometrial cups remain difficult to perform because of the invasive techniques required to obtain cup tissue and because sampling requires termination of the pregnancy. In this study we developed a system to model trophoblast differentiation and trophoblast-immune interactions in vitro and in vivo. We utilized a method of culturing chorionic girdle pieces in serum-fr...
Structural and haemovascular aspects of placental growth throughout gestation in young and aged mares. This investigation was carried out to study the equine placenta from early gestation to near term, with special reference to morphological changes associated with the development of the vasculature of the fetal component of the microcotyledons. Pregnant uteri were removed post mortem from five Thoroughbred mares between 110 and 309 days of gestation, two of which were aged, multiparous animals suffering age-related degenerative changes in their endometrium (endometrosis), while the other three were young, and had primigravid normal healthy uteri. Pieces of endometrium with placenta attached we...
Inhibition of lymphocyte proliferation and activation: a mechanism used by equine invasive trophoblast to escape the maternal immune response. At days 36-38 of gestation, the equine invasive trophoblast cells migrate into the endometrium of the pregnant mare to form the endometrial cups. During their migration, they become surrounded by maternal CD4+ and CD8+ T lymphocytes, and stimulate a cytotoxic antibody response to the paternal major histocompatibility complex class I antigens that they express. Nevertheless, endometrial cup cells remain viable at the site of uterine invasion up to days 80-100 of gestation, suggesting the participation of immunomodulatory mechanisms to the maternal cellular immune response. To determine the effe...
A structural and immunological study of chorionic gonadotrophin production by equine trophoblast girdle and cup cells. Equine chorionic gonadotropin (eCG) production by the fetally derived endometrial cups appears to be necessary for the establishment and maintenance of normal equine pregnancy. Starting at about the 27th day of pregnancy, an equatorial band of trophectodermal cells on the surface of the spherical conceptus forms the chorionic girdle. This girdle consists initially of flat trophectodermal epithelium which corrugates into folds as the cells proliferate. The folds are then pressed against the uterine epithelium by expansion of the conceptus. The cells on the apices of the folds become binucleate ...
Separate sites and mechanisms for placental transport of calcium, iron and glucose in the equine placenta. The placenta is the only channel for transport of nutrients to the conceptus and the fetal nutrient demands increase exponentially to term. The 9 kDa calcium binding protein (calbindin, 9CBP) and the iron binding protein uteroferrin (UF) are proving to be reliable markers for epithelia that mediate active transcellular calcium and iron transport and the glucose transporter proteins (GT1 and GT3) for glucose transport by facilitated diffusion. Light and electron microscope immunocytochemistry have been used on perfusion fixed resin embedded material to establish the distribution of 9CBP, UF, GT...
Scanning electron microscopy of the microcotyledonary placenta of the horse (Equus caballus) in the latter half of gestation. Scanning electron microscopy was used to examine the microstructure of the maternal and fetal placenta from 25 pregnant ponies (Equus caballus) throughout the second half of gestation. Samples of placenta, 2-6 cm(2)in area, were collected from the antimesometrial region of the pregnant horn at 105 days (n=1), 165-219 days (n=5), 260 days (n=3), 270-277 days (n=3), 313-337 days (n=11) and immediately after spontaneous delivery at term (n=2). The maternal microcaruncle appears to be created from a clustering of about 16 uterine crypts encapsulated in a connective tissue sheath. There is a gestat...
A unique exocelom-like space during early pregnancy in the horse. The free allantois and allantochorion of conceptuses from 17 mares between 20 and 90 days of gestation were examined to determine the manner in which the associated mesodermal derivatives differentiated. It was found that a robust basement membrane developed under the allantoic endoderm, and that this basement membrane was partially isolated from the vascular layer of the allantois by a mesothelial layer and an exocelom-like space. The exocelom-like space persisted until approximately the stage of villous formation, and remnants of the space persisted over larger allantoic vessels even later. ...
Equine placental cup cells show glycan expression distinct from that of both chorionic girdle progenitor cells and early allantochorionic trophoblast of the placenta. Using lectin histochemistry on plastic-embedded material, the glycosylation patterns of equine girdle and cup cells, and associated endometrial glands, have been investigated from 37 to 67 days gestation. Results were compared with the glycosylation of the 50-day allantochorionic trophoblast of the established equine placenta that will later form the microcotyledons. The differentiated cup cells, which secrete equine chorionic gonadotropin (eCG), showed a pattern of glycosylation that was distinct both from the progenitor girdle cells and the allantochorionic trophoblast, with granules that bo...
A lectin binding analysis of glycosylation patterns during development of the equine placenta. The glycosylation of the equine interhaemal barrier and areola was studied throughout the period of gestation. Placentae of 35, 37, 50, 119, 152, 200, 280 and 300 days gestation were investigated, using semithin plastic embedded sections and a panel of 15 biotinylated lectins with an avidin-peroxidase revealing system. Glycosylation of the trophoblast and maternal epithelium showed the most change during the first 50 days of gestation, being associated with the initial stages of adhesion and attachment. In the trophoblast, non-bisected tri/tetraantennary complex N-glycan was only evident after...
The potential of collagenase as a new therapy for separation of human retained placenta: hydrolytic potency on human, equine and bovine placentae. The purpose of this study was to determine to what degree bacterial collagenase may digest human placentae compared to equine and bovine placentae. Placenta samples from human, equine and bovine were incubated with bacterial collagenase solution at various concentrations. The degree of hydrolysis and collagen breakdown was measured by the release of total proteins and hydroxyproline into the incubation media. Also, whole placentae were injected via umbilical cord arteries with collagenase solution (200 U/ml, 200 ml total volume in human and 1000 ml in equine) and hydrolysis determined chemical...
Placental localization of relaxin in the pregnant mare. In situ hybridization employing a cRNA probe derived from a 428-bp fragment of equine relaxin was used to localize relaxin mRNA, and immunocytochemistry was used to localize relaxin itself, in tissues of the placenta-endometrium interface recovered between 33 and 153 days of gestation from mares carrying intraspecific horse, interspecific mule and extraspecific donkey conceptuses. Immunocytochemical staining was also used to localize trophoblast-specific and class I major histocompatibility complex (MHC) antigens on some specimens. Relaxin mRNA and relaxin were both present in the single-cell ...
Analysis of MHC class I expression in equine trophoblast cells using in situ hybridization. Down-regulation of major histocompatibility complex (MHC) genes by trophoblast cells is considered to be a primary mechanism preventing maternal immune rejection of the fetal-placental unit in mammalian pregnancy by rendering these cells, which form the primary barrier between mother and fetus, relatively non-antigenic. In situ hybridization with probes encoding human and horse MHC class I genes was used to characterize the pattern of MHC class I mRNA expression in the various forms of horse trophoblast. Strong hybridization signals were observed in the invasive trophoblast cells of chorionic ...
The maternal leucocyte response to the endometrial cups in horses is correlated with the developmental stages of the invasive trophoblast cells. Invading trophoblasts form endometrial cups in the endometrium of the pregnant mare. In the present study we characterized the maternal leucocyte response to endometrial cups from their formation to their regression. The maternal leucocyte response was correlated with the stages of trophoblast development. (1) Aggregates of CD4+ and CD8+ cells were present between the migrating and differentiating endometrial cup trophoblasts and surrounding the forming endometrial cups. (2) Numbers of CD4+ cells within the mature endometrial cups were much reduced. At the periphery of the endometrial cups CD4...
Release of lipid from the equine placenta during in vitro incubation. An in vitro incubation technique was used to examine release of lipids from the equine placenta. Placental tissue was obtained at term (n = 5, term = 320-365 days) and earlier in gestation (n = 8, mean = 266 days). Term placentae were incubated at two temperatures, 4 degrees C (control) and 37 degrees C for 2 h. Pre-term placentae were incubated at 37 degrees C with two different concentrations of fatty acid in the medium. Tissues and media were analysed for their lipid concentrations. Term and pre-term placentae released free fatty acid (FFA) and phospholipid into the incubation medium during...