Placentation in the paca (Agouti paca L)

Background: the paca is a South American rodent with potential as a commercial food animal. We examined paca placenta as part of a wider effort to understand the reproductive biology of this species.Methods: Thirteen specimens between midgestation and term of pregnancy were studied by light and transmission electron microscopy.Results: the placenta is divided into several lobes separated by interlobular trophoblast. Maternal arterial channels and fetal veins are found at the centre of each lobe. In the labyrinth, maternal blood flows through trophoblast-lined lacunae in close proximity to the fetal capillaries. The interhaemal barrier is of the haemomonochorial type with a single layer of syncytiotrophoblast. Caveolae occur in the apical membrane of the syncytiotrophoblast and recesses in the basal membrane, but there is no evidence of transtrophoblastic channels. The interlobular areas consist of cords of syncytiotrophoblast defining maternal blood channels that drain the labyrinth. Yolk sac endoderm covers much of the fetal surface of the placenta. The subplacenta comprises cytotrophoblast and syncytiotrophoblast. There are dilated intercellular spaces between the cytotrophoblasts and lacunae lined by syncytiotrophoblast. In the junctional zone between subplacenta and decidua, there are nests of multinucleated giant cells with vacuolated cytoplasm. The entire placenta rests on a pedicle of maternal tissue. An inverted yolk sac placenta is also present. The presence of small vesicles and tubules in the apical membrane of the yolk sac endoderm and larger vesicles in the supranuclear region suggest that the yolk sac placenta participates in maternal-fetal transfer of protein.Conclusion: the paca placenta closely resembles that of other hystricomorph rodents. The lobulated structure allows for a larger exchange area and the development of precocial young.

Transplacental Transfer of Iron in the Water Buffalo (Bubalus bubalis): Uteroferrin and Erythrophagocytosis

The objectives of this investigation were to understand transplacental transport of iron by secreted uteroferrin (UF) and haemophagous areas of water buffalo placenta and clarify the role(s) of blood extravasation at the placental-maternal interface. Placentomes and interplacentomal region of 51 placentae at various stages of gestation were fixed, processed for light and transmission electron microscopy, histochemistry and immunohistochemistry. Haemophagous areas were present in placentomes collected between 4 and 10 months of pregnancy. Perl's reaction for ferric iron was negative in placentomes, but positive in endometrial glands. Positive staining for UF indicated areas in which it was being taken up by phagocytosis and/or fluid phase pinocytosis in areolae of the interplacentomal mesenchyme, with little staining in endometrial stroma. Imunohistochemistry detected UF in trophectoderm of haemophagous regions of placentomes and in other parts of the foetal villous tree, but the strongest immunostaining was in the epithelial cells and lumen of uterine glands. Ultrastructural analyses indicated that erythrophagocytosis was occurring and that erythrocytes were present inside cells of the chorion that also contained endocytic vesicles and caveolae. Results of this study indicate that both the haemophagous areas of placentomes and the areolae at the interface between chorion and endometrial glands are important sites for iron transfer from mother to foetal-placental tissues in buffalo throughout pregnancy.

Development of the inverted visceral yolk sac in three species of caviids (rodentia, caviomorpha, caviidae)

Guinea pig related rodents possess numerous derived placental characters. We attempt to identify diversity within the visceral yolk sac and its association with the chorioallantoic placenta in three species of caviids, two of them possessing a capsule formed by the decidua that covers the chorioallantoic placenta. The results verify that in early pregnancy all three species have in inverted yolk sac placenta. In advanced pregnancy the species differ: Galea spixii, as representative without a capsule, bear a yolk sac in apposition to the chorioallantoic placenta with signs of exchange activity until term. Galea is similar to other caviomorphs in this respect. In Dasyprocta leporina and Cuniculus paca, the representatives possessing a capsule, the yolk sac endoderm lacks signs of substance exchange. Evidently, the presence of a capsule prevents such ail interaction. The variations established here must be considered if animal models for human placentation are required which have restricted access to the chorioallantoic placenta from the outside. (C) 2008 Elsevier Ltd. All rights reserved.

IFPA Meeting 2010 Workshop Report I: Immunology; Ion transport; Epigenetics; Vascular reactivity; Epitheliochorial placentation; Proteomics

Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 there were twelve themed workshops, six of which are summarized in this report 1. The immunology workshop focused on normal and pathological functions of the maternal immune system in pregnancy. 2. The transport workshop dealt with regulation of ion and water transport across the syncytiotrophoblast of human placenta. 3. The epigenetics workshop covered DNA methylation and its potential role in regulating gene expression in placental development and disease. 4. The vascular reactivity workshop concentrated on methodological approaches used to study placental vascular function. 5. The workshop on epitheliochorial placentation covered current advances from in vivo and in vitro studies of different domestic species. 6. The proteomics workshop focused on a variety of techniques and procedures necessary for proteomic analysis and how they may be implemented for placental research. (C) 2011 Published by IFPA and Elsevier Ltd.

Fetal and maternal lesions of cyanide dosing to pregnant goats

The present work evaluated the pathological effects in both dams and their fetuses of cyanide ingestion during pregnancy using goat as animal model. From the Day 24 of pregnancy, three pregnant goats were dosed by gavage with 3.0 mg KCN/kg bw/day, and two others received only tap water. All dams were euthanized and necropsied at Day 120 of pregnancy. The fetuses were examined carefully for gross abnormalities. Determinations of cyanide and thiocyanate were performed in maternal and fetal blood and in amniotic fluid. Samples of several organs were collected for histopathologic evaluation. No clinical changes were seen in any animal throughout the pregnancy. No malformations or dead fetuses were observed: however, placenta from one treated goat presented increased cotyledon surface area occupied by vascular lumina. Histological lesions in KCN-treated dams consisted of vacuolation of hepatocytes and thyroid follicular cells, increased number of vacuoles on thyroid follicular colloid. and spongiosis of cerebral, internal capsule, and cerebellar peduncles tracts. Fetuses from these mothers showed vacuolation of hepatocytes and thyroid follicular cells, and spheroids in the cerebellar white matter. Levels of cyanide and thiocyanate were higher in maternal than fetal blood, which suggests that these substances were largely but not freely transferred from mothers to fetuses. (C) 2009 Elsevier B.V. All rights reserved.

Caracterização da fusão caruncular em gestações naturais e de conceptos bovinos clonados

Barreto R.S.N., Miglino M.A., Meirelles F.V., Visintin J.A., Silva S.M., Burioli K.C., Fonseca R., Bertan C., Assis Neto A.C. & Pereira F.T.V. 2009. [Characterization of the caruncular fusion in gestations of natural and cloned bovine conceptuses.] Caracterizacao da fusao caruncular ern gestacoes naturais e de conceptos bovinos clonados. Pesquisa Veterinaria Brasileira 29(10):779-787. Laboratorio de Morfofisiologia da Placenta e Embriao, Faculdade de Zootecnia, Universidade Estadual Paulista, SP294 Km 651, Dracena, SP 17900-000, Brazil. E-mail: fverechia@dracena.unesp.brThe objective of the study was to compare the characteristics of the caruncular fusion in gestations of non-cloned and cloned conceptuses. The non-cloned conceptuses were divided according to the gestation period: Group 1 (2 to 3 months; n=9),II (4 to 6; n=9); III (7 to 8; n=10) and IV (9 n=7). The cloned conceptuses formed the Group V: 9 months; n=4. The caruncles were observed macroscopically (number and dimensions: length, width and height), microscopically and submitted to statistical analysis (5% of significance). We observed three types of macroscopic caruncular fusions: oval (morphologically normal); two united adjacent caruncles and the lobulated type, characterized by regions with several united caruncles presenting a false fusion or deformation of the caruncular parenchyma. The length of the caruncles was 1.55 +/- 0.57; 2.45 +/- 0.55; 4.66 +/- 2.0 and 5.72 +/- 1.90cm for the groups 1, 11, 111, IV respectively. As for the height, the caruncles presented a lineal growth during the gestation: 0.40 +/- 0.15; 0.57 +/- 0.21; 1.0 +/- 0.48 and 1.80 +/- 0.91cm, for the respective groups 1, 11, 111 and IV. The width of the caruncles was similar between the groups I and 11 (0.97 +/- 0.30 e 1.42 +/- 0.71 cm) and the groups III and IV (2.68 +/- 1.22 and 3.52 +/- 1.16cm). When the group V was compared to the IV, the caruncles of the group V presented a larger length (5.72 +/- 1.90 vs. 7.88 +/-.13cm) and width (3.52 +/- 1.16 vs. 4.93 +/- 1.46cm), however they were similar in height (1.80 +/- 0.91 and 2.25 +/- 0.67cm). We verified that in gestations of cloned conceptuses the caruncles presented a larger development than in gestations of non-cloned conceptuses. The fusioned caruncles presented measurements statistically similar to the isolated ones in all the parameters and groups. Under light microscopy, we observed the formation of a stromal axis from the basis of the caruncle to the apex of the fusional fissure, with the histological constitution similar to the endometrial stroma. Three microscopic shapes were also unpublished defined: true fusion with a single axis evident below the fusional fissure; pseudofusion with a double axis in H shape and false fusion with absence of the axis. The first two formats were associated to the oval and lobulated caruncles and the last one to the false fusion with deformation of the caruncle parenchyma. The fusional axis increased in size along the gestation among the groups I, II, III and IV. The group V presented a larger length and width of the axis when compared to the group IV. Thus, in gestations of cloned conceptuses a destruction of the lateral epithelium of the caruncles is associated to an incompetence in the maternal-fetal interdigitation, that compromises the cotyledonary fusion. We suggest that, in gestations derived of cloned conceptuses, the increase of the size of the caruncular fusions is possibly associated to a compensatory mechanism for the metabolic exchanges between mother and fetus, in reason of the smallest number of isolated caruncles.

Gene expression in placentation of farm animals: An overview of gene function during development

Eutherian mammals share a common ancestor that evolved into two main placental types, i.e., hemotrophic (e.g., human and mouse) and histiotrophic (e.g., farm animals), which differ in invasiveness. Pregnancies initiated with assisted reproductive techniques (ART) in farm animals are at increased risk of failure; these losses were associated with placental defects, perhaps due to altered gene expression. Developmentally regulated genes in the placenta seem highly phylogenetically conserved, whereas those expressed later in pregnancy are more species-specific. To elucidate differences between hemotrophic and epitheliochorial placentae, gene expression data were compiled from microarray studies of bovine placental tissues at various stages of pregnancy. Moreover, an in silico subtractive library was constructed based on homology of bovine genes to the database of zebrafish - a nonplacental vertebrate. In addition, the list of placental preferentially expressed genes for the human and mouse were collected using bioinformatics tools (Tissue-specific Gene Expression and Regulation [TiGER] - for humans, and tissue-specific genes database (TiSGeD) - for mice and humans). Humans, mice, and cattle shared 93 genes expressed in their placentae. Most of these were related to immune function (based on analysis of gene ontology). Cattle and women shared expression of 23 genes, mostly related to hormonal activity, whereas mice and women shared 16 genes (primarily sexual differentiation and glycoprotein biology). Because the number of genes expressed by the placentae of both cattle and mice were similar (based on cluster analysis), we concluded that both cattle and mice were suitable models to study the biology of the human placenta. (C) 2011 Elsevier B.V. All rights reserved.