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In this study we have tracked glycogen and glycoprotein flux associated with nutrient uptake into trophoblast in early deciduochorial and later haemochorial placenta.α-amylase, glycogen synthase and glycogen phosphorylase were immunohistochemically localised in 6–14 week and term placenta and first trimester decidua. Placentae of 4–18 weeks' gestation and term were also stained with 22 biotinylated...
The trophoblast binucleate cell [BNC] is central to the structure and function of all ruminant placentas so far investigated. The Giraffidae are considered to form a separate family within the ruminant suborder.The structure and function of two [mid and late pregnant] giraffe placentas and two term okapi placentas have been investigated immunocytochemically.Their major characteristics: polycotyledonary...
Syncytial nuclear aggregates (SNAs) are increased in pregnancy complications and include ‘true’ syncytial knots and inter-villous bridges. Apparent nuclear overlay caused by sectioning artefacts are frequently counted from single sections. Haematoxylin and eosin stained serial sections were assessed for frequency of SNA subtypes in placentas from normal, preeclamptic and fetal growth restricted (FGR)...
Blood vessel glycosylation at the fetomaternal interface of four near-term specimens of tammar wallaby, Macropus eugenii, has been examined at days 23–26 of the 26.5 day pregnancy and compared with that of other species.A panel of 23 lectins was used to compare vasculature in tammar with non-mammalian (shark, skink) and eutherian species at early and late gestation (camel, horse and alpaca), and term/near-term...
The Laotian rock rat is a relict species in a sister group relationship to hystricognath rodents (Hystricognathi). We asked whether there were similarities in placentation that might reflect this relationship or differences that might cast light on the evolution of Hystricognathi.We examined the reproductive tract of nonpregnant (n = 5), early (n = 3) and mid to late gestation (n = 2) females. Selected...
Syncytial nuclear aggregates (SNAs) are increased in pregnancy complications; however, little is known about their origin or function. This study aimed to characterise SNAs in more detail than has been reported previously.Immunohistochemistry and morphological examination at the light and ultrastructural level were used to determine the nature and structure of SNAs.SNAs comprising bridges and syncytial...
Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At IFPA meeting 2011 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology: 1) immunology; 2) epigenetics; 3) comparative placentation; 4) trophoblast differentiation; 5) stem cells.
Histiotrophe is now recognized as being an important feature of early human pregnancy, providing nutrients and growth factors to the developing embryo. Our aim was to examine the glycan composition of histiotrophe from first trimester decidua and to compare it with secretions present in endometrial glands from the late secretory phase of the menstrual cycle.Twenty samples of decidua from pregnancies...
Macrophages, known as Hofbauer cells, are most abundant in placental villous stroma in the first and second trimesters. Their functions are not well defined. We have used a combination of in situ and in vitro methods to characterise these cells. Lectin histochemistry and immunohistochemistry were used to identify macrophages in situ. The lectin from Maclura pomifera (MPA) was found to mark cells bearing...
Synthetic glucocorticoids (GCs) are given to women with threatened preterm labour but their administration has been linked to reduced infant birthweight. The underlying mechanisms are unknown, but impaired placental development and/or function has been implicated. The activity of the system A amino acid transporter is decreased in placentas from pregnancies complicated by fetal growth restriction...
Placental amino acid transport is essential for optimal fetal growth and development, with a reduced fetal provision of amino acids being implicated as a potential cause of fetal growth restriction (FGR). Understanding placental insufficiency related FGR has been aided by the development of mouse models that have features of the human disease. However, to take maximal advantage of these, methods are...
The binucleate trophoblast cells (BNCs) in the ruminant placenta are a unique feature of this taxon. These cells produce several secretory proteins and transfer these across the fetomaternal barrier into the dam. We used lectin histochemistry with a panel of 24 lectins to characterise the glycosylation pattern of BNC secretory granules in a variety of ruminants. Seven species out of three ruminant...
Bats are a highly successful, widely distributed group, with considerable variation in placental structure. The Egyptian slit-faced bat Nycteris thebaica is a member of one of the few families with previously undescribed placentation. It was found that, although the interhemal type of the Nycteris placenta is endotheliochorial with a single layer of cytotrophoblast, the arborizing pattern of the maternal...
The placentation of the Hottentot golden mole (Amblysomus hottentotus) has been examined using light and electron microscopy and lectin histochemistry of nine specimens at both mid and late gestation. The placentae were lobulated towards the allantoic surface and the lobules contained roughly parallel arrays of labyrinthine structures converging on a central spongy zone. At mid gestation, the arrays...
In the placental villus, cells attach to basement membrane via integrin α6β4 and adhere both laterally and apically to their neighbours. The most prominent adhesive specialisation seen using the electron microscope is the desmosome, which connects cytotrophoblast cells (CTB) laterally and also contributes to the attachment of CTB to the overlying syncytium. However, numerous cadherins and other junctional...
At the tips of anchoring villi, cytotrophoblast (CTB) proliferation leads to a process of multilayering in which cells lose their attachment to the villous basement membrane and develop into columns, within which they adhere to one another using desmosomes, with associated intermediate filament bundles. Non-desmosomal cadherins, tight junction proteins and other adhesion molecules are also present,...
Hybridisation occurs rarely in nature and experiments using interspecific transfer of embryos generally result in implantation failure. Here we show that appropriate glycosylation of the apposing surfaces of endometrium and trophoblast probably is an important factor and may play a critical role in pregnancy success. Examination of closely related species shows that each has its own specific pattern...
In Africa, approximately 25 million pregnant women are at risk of Plasmodium falciparum infection each year, one in four has evidence of placental involvement and up to half of these may be associated with low birth weight outcomes. In infected pregnant women, the placenta is an ideal site for the accumulation of the parasites, and this reduces in extent in subsequent pregnancies. Recent data indicate...
Pre-eclampsia (PE) and intrauterine growth restriction (IUGR) are associated with aberrant cell turnover, including increased apoptosis, in placental villous trophoblast. The increased apoptosis is associated with exaggerated expression of p53, which promotes cell cycle arrest or apoptosis via downstream proteins such as p21 or Bax. These changes in apoptosis and p53 expression are purported to result...
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