Large Offspring or Large Placenta Syndrome? Morphometric Analysis of Late Gestation Bovine Placentomes from Somatic Nuclear Transfer Pregnancies Complicated by Hydrallantois
Open Access
- 1 July 2006
- journal article
- Published by Oxford University Press (OUP) in Biology of Reproduction
- Vol. 75 (1), 122-130
- https://doi.org/10.1095/biolreprod.106.051581
Abstract
Somatic nuclear transfer (NT) in cattle is often complicated by fetal oversize (i.e., large offspring syndrome), hydrallantois, and placentomegaly in late gestation. The aims of this work were to obtain data on the placentome structure in NT-recipient cows with hydrallantois (NTH) and to relate these with fetal and placental weights to better understand the abnormalities observed in NTH pregnancies during the third trimester. Pregnant cows were slaughtered between Gestation Days 180 and 280. The fetuses were weighed, and the placentomes were numbered and weighed. Placentomes were examined by histologic and stereological techniques. Macroscopic data showed that placental overgrowth preceded fetal overgrowth, and the ratio of the fetal to the total placentome weight in the NTH group was lower than that in controls after Gestation Day 220. This suggests that placental overgrowth is due to placental default rather than due to fetal overgrowth, as shown also by stereological analysis showing primary deregulation of the growth of cotyledonary tissues. Observed alterations, such as thinning of the maternal epithelium within placentomes and increased trophoblastic surface, could be secondary adaptations. Thus, placental growth deregulations would be due to modifications of the expression of placental factors. Various examples of placental deficiency were observed, suggesting that some fetal abnormalities observed in NTH calves, such as enlarged heart, enlarged umbilical cord, and abdominal ascites, are consequences of placental dysfunction. Therefore, the condition described by the term “large offspring syndrome” might better be described by “large placenta syndrome,” because this syndrome affects an average of 50% of late-gestation NT pregnancies. No conclusion can be drawn from this work on apparently normal pregnancies.Keywords
This publication has 38 references indexed in Scilit:
- Zootechnical Performance of Cloned Cattle and Offspring: Preliminary ResultsCloning and Stem Cells, 2004
- Coordination between donor cell type and cell cycle stage improves nuclear cloning efficiency in cattleTheriogenology, 2003
- Novel Approaches and Hurdles to Somatic Cloning in CattleCloning and Stem Cells, 2002
- Cloning of calves from various somatic cell types of male and female adult, newborn and fetal cowsReproduction, 2000
- A Simplified Method for the Reconstruction of Fully Competent Mouse Zygotes from Adult Somatic Donor NucleiCloning, 2000
- Cloning of male mice from adult tail-tip cellsNature Genetics, 1999
- Stereology and its impact on our understanding of human placental functional morphologyMicroscopy Research and Technique, 1997
- Pluripotent bovine embryonic cell lines direct embryonic development following nuclear transferBiology of Reproduction, 1996
- Comparison of birth weight and growth characteristics of bovine calves produced by nuclear transfer (cloning), embryo transfer and natural matingAnimal Reproduction Science, 1995
- Bovine Inner Cell Mass Cells as Donor Nuclei in the Production of Nuclear Transfer Embryos and Calves1Biology of Reproduction, 1994