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HERO ID
1558874
Reference Type
Journal Article
Title
Sheep models of intrauterine growth restriction: Fetal adaptations and consequences
Author(s)
Morrison, JL
Year
2008
Is Peer Reviewed?
Yes
Journal
Clinical and Experimental Pharmacology and Physiology
ISSN:
0305-1870
EISSN:
1440-1681
Volume
35
Issue
7
Page Numbers
730-743
PMID
18498533
DOI
10.1111/j.1440-1681.2008.04975.x
Web of Science Id
WOS:000256103500004
Abstract
1. Intrauterine growth restriction (IUGR) has been associated with poor perinatal health outcomes. Animal models have been used to investigate why IUGR is associated with a poor prognosis. The sheep has been used extensively as an experimental model for IUGR with poor placental substrate supply to the fetus induced using a range of methods, including the surgical ablation of the majority of endometrial caruncles prior to conception, experimental induction of maternal hyperthermia, ligation of an umbilical artery or embolization of the placenta in late gestation and maternal overnutrition in the pregnant adolescent ewe. 2. Fetal adaptations to fetal hypoxia and hypoglycaemia include activation of the fetal hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system and an associated increase in circulating cortisol and noradrenaline concentrations. Fetal cardiovascular responses vary according to the method used to induce placental dysfunction. 3. Although an array of experimental models has been used to induce placental dysfunction at different stages of fetal development, each leads to remarkably similar fetal growth, metabolic, neuroendocrine and cardiovascular adaptations and consequences. The extent and range of the fetal physiological adaptations to chronic placental insufficiency are determined by the duration of exposure and the degree of the severity of substrate supply restriction. 4. The present review summarizes how sheep models of IUGR have provided an increased understanding of the nature of the fetal adaptations to IUGR, their longer-term physiological consequences and how to improve clinical management of IUGR in human pregnancies.
Keywords
cardiovascular system; hypoxia; intrauterine; growth restriction; placenta; sheep
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