The equine placenta is a vital organ that facilitates nutrient and gas exchange between the mare and the developing fetus during pregnancy. It plays a role in hormone production and immune modulation to support fetal development. The placenta in horses is classified as a diffuse, epitheliochorial type, characterized by the widespread attachment of the chorionic villi to the endometrium. Research on the equine placenta encompasses studies on its structure, function, and the physiological processes involved in its development and maintenance. This page compiles peer-reviewed research studies and scholarly articles that explore the morphology, function, and clinical implications of the placenta in equine reproduction and health.
Schöniger S, Gräfe H, Wipplinger M, Schoon HA.In mares, placental diseases are a common cause of pregnancy failure and they can have an economic impact on the horse breeding industry. To our knowledge no published data on TLR expression in the equine placenta exist. This study examined the expression of TLR 2, 4 and 6 as transcript and protein in the placenta (chorioallantois) of 14 foals born alive. By PCR, all examined placental samples contained TLR 2, 4 and 6 transcripts. Using immunohistochemistry, trophoblasts and allantoic epithelium were immunopositive for TLR 2, 4 and 6 in all placental samples. The majority of placental samples ...
Read JE, Cabrera-Sharp V, Offord V, Mirczuk SM, Allen SP, Fowkes RC, de Mestre AM.Equine chorionic girdle trophoblast cells play important endocrine and immune functions critical in supporting pregnancy. Very little is known about the genes and pathways that regulate chorionic girdle trophoblast development. Our aim was to identify genes and signalling pathways active in vivo in equine chorionic girdle trophoblast within a critical 7-days window. We exploited the late implantation of the equine conceptus to obtain trophoblast tissue. An Agilent equine 44K microarray was performed using RNA extracted from chorionic girdle and chorion (control) from equine pregnancy days 27, ...
Read JE, Cabrera-Sharp V, Offord V, Mirczuk SM, Allen SP, Fowkes RC, de Mestre AM.Equine chorionic girdle trophoblast cells play important endocrine and immune functions critical in supporting pregnancy. Very little is known about the genes and pathways that regulate chorionic girdle trophoblast development. Our aim was to identify genes and signalling pathways active in vivo in equine chorionic girdle trophoblast within a critical 7-days window. We exploited the late implantation of the equine conceptus to obtain trophoblast tissue. An Agilent equine 44K microarray was performed using RNA extracted from chorionic girdle and chorion (control) from equine pregnancy days 27, ...
Wynn MAA, Ball BA, May J, Esteller-Vico A, Canisso I, Squires E, Troedsson M.The objectives of this study were to compare via liquid chromatography-tandem mass spectrometry (LC-MS/MS) progesterone (P4), 5α-dihydroprogesterone (DHP), allopregnanolone, 3β-hydroxy-5α-pregnan-20-one (3β5P), 20α-hydroxy-5α-pregnan-3-one (20α5P), 5α-pregnan-3β,20α-diol (βα-diol), and 5α-pregnan-3β,20β-diol (ββ-diol) concentrations in plasma of mares with experimentally-induced, ascending placentitis compared to gestationally age-matched control mares. Placentitis was induced via intracervical inoculation of Streptococcus equi spp. zooepidemicus between 260 and 280 days of ge...
Kimura Y, Haneda S, Aoki T, Furuoka H, Miki W, Fukumoto N, Matsui M, Nambo Y.The combined thickness of the uterus and placenta (CTUP) and ultrasonographic images of uteroplacental tissues were investigated in 35 pregnant heavy draft horses in Months 7-12 of pregnancy. The mares were divided into three groups: those pathologically diagnosed as placentitis (placentitis group, n=3); those who had abortion, premature birth, or fetal malformation (abnormal group, n=7); and those who had no abnormal findings (normal group, n=25). In the normal group, CTUP increased as pregnancy progressed from Months 7 (median, 7.08 mm; range, 5.68-11.27) to 12 (13.31 mm; 7.44-16.31 mm) (P<0...
Loux SC, Ball BA.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...
Robles M, Peugnet P, Dubois C, Piumi F, Jouneau L, Bouchez O, Aubrière MC, Dahirel M, Aioun J, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P.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...
Robles M, Dubois C, Gautier C, Dahirel M, Guenon I, Bouraima-Lelong H, Viguié C, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P.Primiparous mares are known to produce smaller foals than multiparous mares. This difference seems to be partly explained by the reduced exchange surface and volume of the placental villi in primiparous compared to multiparous placentas. The effect of maternal parity on foals' post-natal growth, metabolism and sexual maturation, however, has been given little consideration. The objectives of this work were to analyse placental biometry and structure at term, growth of foals and yearlings, their metabolism and testicular maturation at one year of age. Twenty multiparous mares (M), aged over 6 y...
Robles M, Peugnet PM, Valentino SA, Dubois C, Dahirel M, Aubrière MC, Reigner F, Serteyn D, Wimel L, Tarrade A, Chavatte-Palmer P.Ponies and sometimes draft horses are often used as experimental models for horses although size and metabolic parameters are known to vary between horse breeds. So far, there is little information about differences of placental structure and no information about differences of placental function between breeds. The aim of this study was to investigate differences in placental size, structure and function at birth in relation to foal size and weight in ponies, Saddlebred and draft horses. Pony, Saddlebred and draft horse pregnancies were obtained by artificial insemination over 2 successive br...
Robles M, Peugnet PM, Valentino SA, Dubois C, Dahirel M, Aubrière MC, Reigner F, Serteyn D, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P.Following embryo transfer (ET), the size and breed of the recipient mare can affect fetal development and subsequent post natal growth rate and insulin sensitivity in foals. Objective: To investigate placental adaptation in pregnancies where increased or restricted fetal growth was induced through ET between Pony, Saddlebred and Draught horses. Methods: In vivo experiment. Methods: Control Pony (P, n = 21) and Saddlebred (S, n = 28) pregnancies were obtained by artificial insemination. Increased pregnancies were obtained by transferring Pony (P-D, n = 6) and Saddlebred (S-D, n = 8) emb...
Legacki EL, Corbin CJ, Ball BA, Scoggin KE, Stanley SD, Conley AJ.Steroidogenic enzymes in placentas shape steroid hormone profiles in the maternal circulation of each mammalian species. These include 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase (3βHSD) and 17α-hydroxylase/17,20-lyase cytochrome P450 (P450c17) crucial for progesterone and androgen synthesis, respectively, as well as aromatase cytochrome P450 (P450arom) that converts Δ4-androgens to estrogens. 5α-reductase is another important enzyme in equine placentas because 5α-dihydroprogesterone (DHP) sustains pregnancy in the absence of progesterone in the second half of equine pregnancy. DHP a...
Raeside JI.The role of steroids in human medicine is well recognized, but the major contributions made by the large domestic animals as a source of material in the discovery, isolation, and determination of the structure of the steroid hormones is less well appreciated. After a brief reminder of the early efforts to obtain a reliable source of steroids for clinical use, the narrative here is to outline one example where success was ultimately achieved for estrogen replacement therapy. Whereas knowledge of the high concentrations of estrogens in urine of pregnant women and mares dates from the late 1920s,...
Wood PL, Ball BA, Scoggin K, Troedsson MH, Squires EL.Amniotic fluid is essential for the growth and maturation of the fetus prior to parturition. While our knowledge of human amniotic fluid is extensive, current data for equine amniotic fluid is limited. We therefore undertook a detailed lipidomics analysis of equine amniotic fluid. Using a non-targeted high-resolution mass spectrometric lipidomics analysis of equine amniotic fluid, we were able to characterize a diverse array of individual lipids. This non-biased analytical approach detected, for the first time, the presence of (O-acyl)-ω-hydroxy-fatty acids (OAHFA) with up to 52 carbon chain ...
Legacki EL, Ball BA, Corbin CJ, Loux SC, Scoggin KE, Stanley SD, Conley AJ.Equine fetuses have substantial circulating pregnenolone concentrations and thus have been postulated to provide significant substrate for placental 5α-reduced pregnane production, but the fetal site of pregnenolone synthesis remains unclear. The current studies investigated steroid concentrations in blood, adrenal glands, gonads and placenta from fetuses (4, 6, 9 and 10 months of gestational age (GA)), as well as tissue steroidogenic enzyme transcript levels. Pregnenolone and dehydroepiandrosterone (DHEA) were the most abundant steroids in fetal blood, pregnenolone was consistently higher bu...
Jones CJP, Allen WRT, Wilsher S.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...
Barua S, Macedo A, Kolb DS, Wynne-Edwards KE, Klein C.Milk-fat globule epidermal growth factor (EGF) 8 protein (MFGE8), also known as lactadherin, promotes cell adhesion in an Arg-Gly-Asp (RGD)-dependent modus via integrins. In the present study, the expression of MFGE8 was examined in equine endometrium during oestrus and at Days 12 and 16 after ovulation in pregnant and non-pregnant mares and in mares during the 5th month of gestation. Results demonstrated that MFGE8 is expressed at the embryo- and fetal-maternal interface in equine pregnancy. In non-pregnant endometrium its expression was upregulated by oestrogen, a finding that was confirmed ...
Valenzuela OA, Couturier-Tarrade A, Choi YH, Aubrière MC, Ritthaler J, Chavatte-Palmer P, Hinrichs K.Assisted reproductive technologies (ARTs) such as intracytoplasmic sperm injection (ICSI), in vitro embryo culture and embryo transfer (ET) may be associated with alterations in fetal and placental development. In horses, ET has been used for decades. More recently, in vitro embryo production by ICSI and in vitro culture, followed by embryo transfer (ICSI-C) has become an accepted method for clinical foal production. However, no information is available on the effects of ICSI-C or even of standard ET itself on placental and neonatal parameters in horses. We therefore evaluated placental and ne...
Beythien E, Aurich C, Wulf M, Aurich J.Seasonal changes in metabolic rate have been shown in horses and we hypothesized that this leads to the birth of smaller foals early in the year. Mares and their foals were assigned to three groups by day of foaling within the year (e.g. 1 January = day 1): Group 1 (n = 10) day 40-65, group 2 (n = 8) day 67-92, group 3 (n = 9) day 94-121. Groups did not differ with regard to parity. In foals, height at withers and body weight were determined on days 1-5 and weekly until 12 weeks of age. Chest circumference, distances fetlock to carpus, carpus to elbow, poll to nose and crown-rump lengt...
Allen WRT, Stansfield F, Wilsher S.The placenta and fetal gonads of 12 pregnant plains zebra (Equus quagga), estimated to be between 81 and 239 days of gestation, were examined. The diffuse, microcotyledonary zebra placenta appeared, developmentally, to be 3-4 weeks behind its counterpart in horse pregnancy and this, together with the presence of small and long-lived endometrial cups, low levels of zebra chorionic gonadotrophin in maternal serum and few accessory corpora lutea in the maternal ovaries during the first half of gestation, made zebra pregnancy more similar to donkey than horse pregnancy. Zebra fetal gonads enlarged...
Curcio BR, Canisso IF, Pazinato FM, Borba LA, Feijó LS, Muller V, Finger IS, Toribio RE, Nogueira CEW.The overall goal of this study was to assess the efficacy of various therapeutic combinations of estradiol cypionate (ECP, a long-acting estrogen) and altrenogest (ALT, a long-acting progestin) in addition to basic treatment for placentitis with trimethoprim-sulfamethoxazole (TMS) and flunixin meglumine (FM). Specific outcomes measured in this experiment were (i) time from induction of bacterial placentitis to delivery, and foal parameters (high-risk, survival, and birth weight); and (ii) serum steroid concentrations (progesterone, 17α-hydroxyprogesterone, 17β-estradiol, and cortisol) in res...
de Sousa SH, Paludo GR, Freschi CR, Machado RZ, de Castro MB.The aim of this report was to confirm the cause of abortion to be Theileria equi acquired transplacentally in a mare in Federal District, Brazil. The aborted fetus showed a high parasitemia of erythrocytes (80%) by the oval and Maltese cross forms of T. equi. Necropsy of the fetus demonstrated congestion of organs, jaundice, anemia and pronounced spleno- and hepatomegaly. Twelve breeding mares, including the one that aborted and her fetus, tested positive for T. equi infection by universal and multiplex PCR assay. The absence of histopathologic changes such as inflammation and necrosis in the ...
Macpherson ML, Giguère S, Pozor MA, Runcan E, Vickroy TW, Benson SA, Troedsson MHT, Hatzel JN, Larson J, Vanden Berg E, Kelleman AA, Sanchez LC....Eleven pregnant pony mares (D270-326) were administered ceftiofur sodium intramuscularly at 2.2 mg/kg (n = 6) or 4.4 mg/kg (n = 5), once daily. Plasma was obtained prior to ceftiofur administration and at 0.5, 1, 2, 4, 8, 12, and 24 hr after administration. Eight pony mares were re-enrolled in the study at least 3 days from expected foaling to ensure steady-state concentrations of drug at the time of foaling. Mares were administered ceftiofur sodium (4.4 mg/kg, IM) daily until foaling. Parturition was induced using oxytocin 1 hr after ceftiofur sodium administration. Allantoic and am...
Allen WR, Gower S, Wilsher S.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 ...
Pazinato FM, Curcio BDR, Fernandes CG, Santos CA, Feijó LS, Varela AS, Nogueira CEW.The objective of this study was to assess the placental vasculature and microcotyledons in pregnant mares with chronic laminitis. Twenty-six pregnant mares were enrolled in the study, 13 had chronic laminitis (Laminitis Group) and 13 were healthy mares (Healthy Group). Arterial systolic pressure and heart rate were measured in the last 30 days of gestation. After foaling, the fetal membranes were grossly evaluated and samples were harvested for histopathologic examination. All mares had digitalized images taken from chorioallantois for histomorphometry analyses (software-NIH ImageJ). Images we...
Ellinger I.Active placental transport of maternal serum calcium (Ca(2+)) to the offspring is pivotal for proper development of the fetal skeleton as well as various organ systems. Moreover, extracellular Ca(2+) levels impact on distinct processes in mammalian reproduction. The calcium-sensing receptor (CaSR) translates changes in extracellular Ca(2+)-concentrations into cellular reactions. This review summarizes current knowledge on the expression of CaSR and its putative functions in reproductive organs. CaSR was detected in placental cells mediating materno-fetal Ca(2+)-transport such as the murine int...
Aleksic D, Blaschke L, Mißbach S, Hänske J, Weiß W, Handler J, Zimmermann W, Cabrera-Sharp V, Read JE, de Mestre AM, O'Riordan R, Moore T....Pregnancy-specific glycoproteins (PSGs) are members of the carcinoembryonic antigen cell adhesion molecule (CEACAM) family that are secreted by trophoblast cells. PSGs may modulate immune, angiogenic and platelet responses during pregnancy. Until now, PSGs are only found in species that have a highly invasive (hemochorial) placentation including humans, mice and rats. Surprisingly, analyzing the CEACAM gene family of the horse, which has a non-invasive epitheliochorial placenta, with the exception of the transient endometrial cups, we identified equine CEACAM family members that seem to be rel...
Pozor MA, Sheppard B, Hinrichs K, Kelleman AA, Macpherson ML, Runcan E, Choi YH, Diaw M, Mathews PM.Placental changes associated with SCNT have been described in several species, but little information is available in this area in the horse. We evaluated the ultrasonographic, gross, and histopathological characteristics of placentas from three successful and five unsuccessful equine SCNT pregnancies, established using cells from a single donor horse. Starting at approximately 6-month gestation, the pregnancies were monitored periodically using transrectal (TR) and transabdominal (TA) ultrasonography (US) to examine the placentas, fetal fluids, and fetuses. Of the five mares that aborted, one...
Stefanetti V, Marenzoni ML, Passamonti F, Cappelli K, Garcia-Etxebarria K, Coletti M, Capomaccio S.Endogenous retroviruses (ERVs) are proviral phases of exogenous retroviruses that have co-evolved with vertebrate genomes for millions of years. Previous studies have identified the envelope (env) protein genes of retroviral origin preferentially expressed in the placenta which suggests a role in placentation based on their membrane fusogenic capacity and therefore they have been named syncytins. Until now, all the characterized syncytins have been associated with three invasive placentation types: the endotheliochorial (Carnivora), the synepitheliochorial (Ruminantia), and the hemochorial pla...
Klein C.Relaxin is a peptide hormone best known for its action during the latter half of pregnancy, in particular for its softening effect on pelvic ligaments that aids in preparation of the birth canal for the impending delivery of the fetus. The source of relaxin during early pregnancy varies across species, with the CL being the main source in a number of species. The main source of relaxin during late equine pregnancy is the placenta. In mares with impaired placental function, circulating relaxin levels decline before abortion. During early pregnancy, relaxin promotes endometrial angiogenesis thro...
Griffith OW, Brandley MC, Whittington CM, Belov K, Thompson MB.In oviparous amniotes (reptiles, birds, and mammals) the chorioallantoic membrane (CAM) lines the inside of the egg and acts as the living point of contact between the embryo and the outside world. In livebearing (viviparous) amniotes, communication during embryonic development occurs across placental tissues, which form between the uterine tissue of the mother and the CAM of the embryo. In both oviparous and viviparous taxa, the CAM is at the interface of the embryo and the external environment and can transfer signals from there to the embryo proper. To understand the evolution of placental ...
Antczak DF.One of the most intriguing and dramatic examples of immunological tolerance is displayed by the mammalian foetal-placental unit, which thrives as a semi-allograft in the mother's uterus during pregnancy. The success of the so-called foetal allograft stands in stark contrast to the failure of most tissue and organ grafts to survive without genetic matching of donor and recipient or drastic immunosuppression of the recipient's immune system. Experiments conducted over the past 60 years have revealed multiple mechanisms that enable the conceptus to avoid immunological detection or destruction. Ma...
Whitwell KE, Jeffcott LB.Of 211 consecutive thoroughbred foalings, 145 satisfied a set of criteria for normal parturition and foal viability. The fetal membranes from these and from 10 pony foalings have been systematically examined morphologically and quantitatively and the findings compared to those of other authors. Five sites on the allantochorion were consistently devoid of villi. Expulsion usually occurred with the non-villous side outermost. In 24 per cent of allantochorions the non-pregant horn was of equal length or longer than the pregnant horn. These placentae tended to be shed with the villous side outermo...
Silver M.Placental progestagen production and metabolism during pregnancy, the changes which precede parturition and the extent of fetal involvement in the latter processes are compared in the sheep and the horse. Neither species requires the presence of a corpus luteum for maintenance of the latter part of pregnancy, but the mechanisms involved in placental progesterone/progestagen production are very different in the two species. In sheep the primary product is progesterone (P4), levels of which are high in the maternal but not the fetal circulations. By contrast, in the mare P4 is not detectable in ...
Beckers JF, Zarrouk A, Batalha ES, Garbayo JM, Mester L, Szenci O.The two main groups of placental proteins of ruminants are discussed in this paper: chorionic somatomammotropins (placental lactogens) and pregnancy-specific (-associated) proteins. Placental lactogens belong to the prolactin and growth hormone family. They stimulate mammogenesis, fetal growth and maternal metabolism. Pregnancy-specific proteins and pregnancy-associated glycoproteins belong to the aspartic proteinase family like pepsin, cathepsin D and E. These two groups of proteins are secreted in the maternal circulation by the binucleate cells after their migration to and fusion with the u...
Read JE, Cabrera-Sharp V, Offord V, Mirczuk SM, Allen SP, Fowkes RC, de Mestre AM.Equine chorionic girdle trophoblast cells play important endocrine and immune functions critical in supporting pregnancy. Very little is known about the genes and pathways that regulate chorionic girdle trophoblast development. Our aim was to identify genes and signalling pathways active in vivo in equine chorionic girdle trophoblast within a critical 7-days window. We exploited the late implantation of the equine conceptus to obtain trophoblast tissue. An Agilent equine 44K microarray was performed using RNA extracted from chorionic girdle and chorion (control) from equine pregnancy days 27, ...
Nilson JH, Bokar JA, Clay CM, Farmerie TA, Fenstermaker RA, Hamernik DL, Keri RA.Expression of the glycoprotein hormone alpha-subunit gene occurs in the pituitary of all mammals but in placenta of only primates and horses. In humans, two different elements, termed upstream regulatory element (URE) and cAMP response element (CRE), are required for placenta-specific expression of the alpha-subunit gene. The URE binds a protein unique to placenta whereas the CRE binds a ubiquitous protein. Comparative analysis of the promoter-regulatory region of the alpha-subunit gene from a number of mammals indicates that a functional URE has been retained and suggests the potential for pl...
Hinshelwood MM, Liu Z, Conley AJ, Simpson ER.Conversion of androgens to estrogens is catalyzed by aromatase P450 (P450arom; the product of the CYP19 gene). Regulation of tissue-specific expression of P450arom in humans is due, in part, to alternative transcriptional start sites that arise as a consequence of the use of granulosa cells and placental tissue from cows, horses, and pigs (ungulates) in order to determine whether these species, like the human, utilize tissue-specific promoters to drive P450arom expression. The majority of transcripts in the placenta have 5'-termini that differ from those in the ovary upstream of a common site ...
Tait AD, Hodge LC, Allen WR.The production of equilin and the other ring B-unsaturated estrogens by the pregnant mare is anomalous in that they are biosynthesised by a cholesterol-independent pathway. Fetal horse gonads were incubated with tritiated sodium acetate and radiochemically pure 3 beta-hydroxy-5,7-pregnadien-20-one and 3 beta-hydroxy-5,7-androstadien-17-one were isolated. A fetal gonad--placental system is proposed for equilin production, 3 beta-hydroxy-5,7-pregnadien-20-one being a precursor for 3 beta-hydroxy-5,7-androstadien-17-one in the fetal gonad and the latter being the precursor of equilin in the place...
Green JA, Xie S, Szafranska B, Gan X, Newman AG, McDowell K, Roberts RM.The pregnancy-associated glycoproteins (PAGs) are placental antigens that were initially characterized as pregnancy markers in the maternal circulation of domestic ruminant species. They are members of the aspartic proteinase gene family, having greatest sequence identity with pepsinogens. However, some are not capable of functioning as enzymes. The PAGs are associated with a large gene family within the Artiodactyla order (cattle, camels, pigs). So far, no members of this family have been characterized in species outside this order. This report describes the cloning and initial characterizati...
El-Sheikh Ali H, Dini P, Scoggin K, Loux S, Fedorka C, Boakari Y, Norris J, Esteller-Vico A, Kalbfleisch T, Ball B.Improved understanding of the molecular mechanisms underlying ascending equine placentitis holds the potential for the development of new diagnostic tools and therapies to forestall placentitis-induced preterm labor. The current study characterized the equine placental transcriptome (chorioallantois [CA] and endometrium [EN]) during placentitis (placentitis group, n = 6) in comparison to gestationally-matched controls (control group, n = 6). Transcriptome analysis identified 2953 and 805 differentially expressed genes in CA and EN during placentitis, respectively. Upstream regulator analys...
Chavatte P, Holtan D, Ousey JC, Rossdale PD.Major progress on the endocrinology of the pregnant mare has been possible thanks to the catheterised equine fetal preparation developed by Marian Silver. In particular, these preparations led to the identification of the source of progestagens within the feto-placental unit and provided the impetus for further work on their biosynthesis and biological activities. The biosynthesis of the progestagens involves close interaction between the fetus, the endometrium and the placenta, and gives rise to some fundamental biochemical questions. The biological role of the progestagens is also discussed:...
Kimura Y, Haneda S, Aoki T, Furuoka H, Miki W, Fukumoto N, Matsui M, Nambo Y.The combined thickness of the uterus and placenta (CTUP) and ultrasonographic images of uteroplacental tissues were investigated in 35 pregnant heavy draft horses in Months 7-12 of pregnancy. The mares were divided into three groups: those pathologically diagnosed as placentitis (placentitis group, n=3); those who had abortion, premature birth, or fetal malformation (abnormal group, n=7); and those who had no abnormal findings (normal group, n=25). In the normal group, CTUP increased as pregnancy progressed from Months 7 (median, 7.08 mm; range, 5.68-11.27) to 12 (13.31 mm; 7.44-16.31 mm) (P<0...
Douglas RH, Ginther OJ.Prenatal specimens from mares with known breeding dates were used to characterize morphological changes in the fetus and placenta of pony mares. Prenatal characteristics and the day on which each was first found and weights of different components of the equine conceptus are summarized.
Samuel CA, Allen WR, Steven DH.Microcotyledons, which are a distinctive feature of the mature equine placenta, are fully formed by Day 150 of gestation. The fetal component of each microcotyledon is developed from several primary folds of trophoblast which become elaborately subdivided as gestation proceeds. These changes are reflected in the structure of the maternal crypts, which receive the fetal villi. Between Days 60 and 150 of gestation the maternal epithelium is greatly reduced in height. No such change occurs on the fetal side of the placenta, but between Days 100 and 250 a progressive indentation of the epithelium ...
Begg AP, Todhunter K, Donahoe SL, Krockenberger M, Slapeta J.A case of amoebic placentitis in a mare from eastern Australia was diagnosed postpartum by histopathological examination of the placenta. The identity of the etiological agent was confirmed as Acanthamoeba hatchetti by use of diversity profiling based on a next-generation sequencing approach.
El-Sheikh Ali H, Legacki EL, Scoggin KE, Loux SC, Dini P, Esteller-Vico A, Conley AJ, Stanley SD, Ball BA.Equine placentitis is associated with alterations in maternal peripheral steroid concentrations, which could negatively affect pregnancy outcome. This study aimed to elucidate the molecular mechanisms related to steroidogenesis and steroid-receptor signaling in the equine placenta during acute placentitis. Chorioallantois (CA) and endometrial (EN) samples were collected from mares with experimentally induced placentitis (n = 4) and un-inoculated gestationally age-matched mares (control group; n = 4). The mRNA expression of genes coding for steroidogenic enzymes (3βHSD, CYP11A1, CYP17A1, CYP19...
Abd-Elnaeim MM, Leiser R, Wilsher S, Allen WR.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...
Fecteau KA, Haffner JC, Eiler H.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...
Wilsher S, Gower S, Allen WR.A polyclonal human mucin-1 (MUC1) antibody was used to stain immunohistochemically for the presence of MUC1 on the endometrium and fetal membranes in mares between 20 and 309 days of gestation. Western blot analysis demonstrated the presence of a protein equivalent in size to a human MUC1 isoform, MUC1/Y, in equine endometrium, allantochorion and amnion. At all stages of gestation examined immunoreactivity to the MUC1 antibody was detected on the apical surface of the lumenal epithelium of the endometrium and the epithelium lining the mouths and apical regions of the endometrial glands. Furthe...
Jones CJ, Wooding FB, Abd-Elnaeim MM, Leiser R, Dantzer V, Stoddart RW.Studies from this laboratory have shown great diversity in the glycosylation of tissues comprising the interhaemal barrier of species with different placental types. This diversity may be one of the factors preventing interbreeding between species. Glycan expression within the uterine epithelium and trophoblast of the interhaemal barrier was examined to test this proposition in three species with similar diffuse, microcotyledonary, epitheliochorial allantochorionic types of placenta: the horse (Equus caballus) and donkey (Equus asinus), which can interbreed with each other, and the camel (Came...
Sebastian M, Giles R, Roberts J, Poonacha K, Harrison L, Donahue J, Benirschke K.Funisitis, inflammation of the umbilical cord, is well recognized in human placentas. This report describes a case of funisitis associated with leptospiral infection in the placenta of a Thoroughbred foal born prematurely. The umbilical cord had diffuse superficial yellow discoloration along its entire length. Microscopic evaluation showed an exudate of neutrophils admixed with fibrin on the surface. Warthin-Starry staining showed spirochetes in the Wharton's jelly of the umbilical cord. A locally extensive, severe placentitis not involving the star and allantoic cystic hyperplasia were the ot...
Barua S, Macedo A, Kolb DS, Wynne-Edwards KE, Klein C.Milk-fat globule epidermal growth factor (EGF) 8 protein (MFGE8), also known as lactadherin, promotes cell adhesion in an Arg-Gly-Asp (RGD)-dependent modus via integrins. In the present study, the expression of MFGE8 was examined in equine endometrium during oestrus and at Days 12 and 16 after ovulation in pregnant and non-pregnant mares and in mares during the 5th month of gestation. Results demonstrated that MFGE8 is expressed at the embryo- and fetal-maternal interface in equine pregnancy. In non-pregnant endometrium its expression was upregulated by oestrogen, a finding that was confirmed ...
de Toledo A, Nomoto K, Hirano E, Tohda C.Human placental extract and animal-derived placental extracts from pigs and horses host a wide range of biological activities. Several placental products are used as medicines, cosmetics, and healthcare substances worldwide. However, the use of placental extracts for neuronal functioning is currently not established because the number of relevant studies is limited. A few previous reports suggested the neuroprotective effect and dendrite genesis effect of placental extract. However, no studies have reported on neurogenesis in placental extracts. Therefore, we aimed to investigate the effects o...
Ishii M, Kobayashi S, Acosta TJ, Miki W, Yamanoi T, Matsui M, Miyake Y, Miyamoto A.The aim of this study was to clarify the relationship between circulating oxytocin (OT) and PGF(2alpha) metabolite (PGFM) in mares at the third stage of labor and placental expulsion time in order to investigate a cause of retained placenta of which the incidence increase in a heavy draft mare. Blood was sampled every 5 min from foaling to expulsion of the placenta in 18 heavy draft mares to evaluate circulating OT and PGFM. The relationships between OT and PGFM concentration and recorded placental expulsion times were investigated. The results were as follows (1) The highest level of OT conce...
Gerst S, Borchers K, Gower SM, Smith KC.EHV-1 and EHV-4 abortion diagnosis is based upon detailed examination of the aborted fetus. However, in some cases, only the placenta is available for examination. Furthermore, the contribution of lesions in the placenta to pathogenesis and diagnosis of EHV-1 and EHV-4 abortion has been neglected. Objective: To assess the utility of placental examination in equine herpesvirus-1 (EHV-1) and EHV-4 abortion diagnosis. Methods: Sections of allantochorion from 49 herpesvirus abortions were analysed by PCR, in situ hybridisation and immunostaining. Results: Virus-specific nested PCR confirmed the pr...
Valenzuela OA, Couturier-Tarrade A, Choi YH, Aubrière MC, Ritthaler J, Chavatte-Palmer P, Hinrichs K.Assisted reproductive technologies (ARTs) such as intracytoplasmic sperm injection (ICSI), in vitro embryo culture and embryo transfer (ET) may be associated with alterations in fetal and placental development. In horses, ET has been used for decades. More recently, in vitro embryo production by ICSI and in vitro culture, followed by embryo transfer (ICSI-C) has become an accepted method for clinical foal production. However, no information is available on the effects of ICSI-C or even of standard ET itself on placental and neonatal parameters in horses. We therefore evaluated placental and ne...
Fenstermaker RA, Farmerie TA, Clay CM, Hamernik DL, Nilson JH.Expression of the glycoprotein hormone alpha-subunit gene occurs in the pituitaries of all mammals and in the placentas of primates and horses. In humans, tandem cAMP response elements (CREs), located in the proximal promoter-regulatory region of the alpha-subunit gene, act together with an adjacent upstream regulatory element to confer placenta-specific expression. Here, we report that the alpha-subunit genes of Old World Monkeys contain a single functional CRE. This suggests that tandem CREs are unique to higher primates and humans and are not absolutely required for placenta-specific expres...
Rapacz-Leonard A, Kankofer M, Leonard M, Wawrzykowski J, Dąbrowska M, Raś A, Paździor-Czapula K, Janowski T.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...
