			Home About us Contact

Placental Angiogenesis (placental + angiogenesi)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	50%

Selected Abstracts

Angiogenesis in the Caprine Caruncles in Non-Pregnant and Pregnant Normal and Swainsonine-Treated Does

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 7 2007
S.A. Hafez
Abstract Microvascular corrosion casts of caruncles from non-pregnant and pregnant doe goats at 4, 7, 10, 13, 16, and 18 weeks were examined with scanning electron microscopy. The internal convex surface of the caruncles of non-pregnant does was covered with capillary meshes of regular diameter and form, without crypts. As pregnancy advanced the complexity of the vasculature increased: at 4 weeks the surface showed a pattern of ridges separated by troughs. At later stages, branches of radial arteries penetrated the periphery forming an extensive mesh of capillaries on the concave surface. Capillary diameters increased significantly during pregnancy, especially after 4 weeks, when large flattened sinusoids formed. These sinusoids had a great deal of surface area for potential contact with the fetal component. The caprine placenta is usually considered to have increased interhemal distance compared with endotheliochorial and hemochorial types: our results suggest that the very extensive development of sinusoids and crypts may compensate for any negative consequences of the placental architecture. Placental angiogenesis, which is physiologically normal, may serve as a general model of this process in other circumstances, such as tumor. The effect of swainsonine (active compound of locoweed and a potential anticancer drug) on vascular development showed no differences in sinusoidal diameters at 7 weeks, but a decrease in capillary density was noted. Swainsonine caused a great distortion to the vasculature at 18 weeks. The effects of this compound on the vascular development lend credibility to its potential as an anticancer agent. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source]

Immunohistochemical Localization of Oestrogen Receptors , and ,, Progesterone Receptor and Aromatase in the Equine Placenta

REPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2009
MMM Abd-Elnaeim
Contents The functions of placental oestrogens during equine pregnancy are still unclear. Yet, they may act predominantly as local regulators of growth and differentiation in the microplacentomes. Thus, expression patterns of oestrogen receptors (ERs) , and , were investigated in the microcotyledonary placenta from pregnant mares at 110, 121, 179, 199 and 309 days of gestation by immunohistochemistry. In microplacentomes, both the ER isoforms were detected in trophoblast (T) cells, chorionic villous stroma (FS), microcaruncular epithelium (ME) and microcaruncular stroma (MS). Proportions of positive cells were 38,91% (T), 11,41% (FS), 55,89% (ME), 17,51% (MS) for ER, and 66,76% (T), 21,37% (FS), 41,68% (ME) and 24,55% (MS) for ER,. Between days 110 and 199, proportions of cells positive for progesterone receptor (PR) varied between 19% and 62% (T), 3% and 50% (CS), 15% and 46% (ME), and 4% and 33% (MS). At day 309, PR was virtually absent in T, CS and ME (percentages < 0.1), whereas in MS 14.3% of cells were still positive. The expression of ERs and PR in equine microplacentomes gives evidence for a role of placental steroids as regulators of placental growth, differentiation and function. The detection of ER,, ER, and PR in foetal and maternal vascular tissue suggests that placental steroids are also involved in the control of placental angiogenesis and,/or vascular functions. The co-localization of ERs with aromatase in T suggests auto- or intracrine functions of oestrogens in this cell type. [source]

Determinants of Placental Vascularity

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2004
Donald S. Torry
Problem:, Vascular growth during implantation and placentation is critical for successful gestation and it is thought that vascular insufficiencies during placentation contribute to a number of obstetrical complications. However, relatively little is known regarding the regulation of angiogenesis in the placenta. Method of study:, We review literature concerning the potential significance of inadequate placental vascularity as a contributor to the obstetrical complications of spontaneous abortion, fetal growth restriction and preeclampsia. Gene expression assays were used to compare fluctuations of placenta growth factor (PlGF) and PlGF receptor expression in normal and preeclamptic trophoblast in vitro. Results:, Studies have shown that common obstetrical complications manifest altered placental vascularity. Both intrinsic defects (gene knockouts) and extrinsic factors (O2 tension, cytokines, etc) may be responsible for the defects. Some of these factors have been shown to influence trophoblast vascular endothelial growth factor (VEGF)/PlGF expression suggesting this particular family of angiogenic proteins play an important role in placental angiogenesis. Conclusion:, Placental vascularization reflects a complex interaction of regulatory factors. Understanding the regulation of vascular growth in the placenta will provide much needed insight into placenta-related vascular insufficiencies. [source]

Biology of the prolactin family in bovine placenta.

ANIMAL SCIENCE JOURNAL, Issue 1 2006

ABSTRACT Bovine placenta produces an array of proteins that are structurally and functionally similar to pituitary prolactin. Bovine placental lactogen (bPL) is a glycoprotein hormone that has lactogenic and somatogenic properties. Purified bPL contains several kinds of isoforms that are created by alternative splicing and/or multiple glycosylation patterns. bPL can activate the prolactin (PRL) receptor-mediated signaling pathway as well as PRL does. The bPL mRNA is transcribed in trophoblast binucleate cells, and synthesized bPL protein is stored in membrane-bound secretory granules. The message encoding bPL is first detectable in trophoblast binucleate cells at approximately day 20 of gestation at, or shortly after, the appearance of binucleate cells in the trophoblast. Most binucleate cells are detected as expressed bPL in the placenta. Bovine PL may be the determinant in trophoblast differentiation. Although the biological activities of bPL have long been studied, the precise role of bPL is still largely unclear. This article reviews and discusses the biological roles of bPL, focusing on luteal function, fetal growth and pregnancy-associated maternal adaptation, mammogenesis and lactogenesis, and placental angiogenesis. The precise biological function of bPL needs to be further evaluated. [source]