Submitted March 11, 2007
Returned for revision April 7, 2007
Accepted April 23, 2007
Pregnancy
Placental Growth, Angiogenic Gene Expression, and Vascular
Development in Undernourished Adolescent Sheep
Justin Luther ,
John Milne ,
Raymond Aitken ,
Masatoshi Matsuzaki ,
Lawrence Reynolds ,
Dale Redmer ,
and
Jacqueline Wallace *
* To whom correspondence should be addressed. E-mail: jacqueline.wallace{at}rri.sari.ac.uk.
Abstract
Limiting maternal nutrient intake during ovine adolescent pregnancy progressively depleted maternal body reserves, impaired fetal nutrient supply and slowed fetal soft tissue growth. The present study examined placental growth, angiogenic gene expression and vascular development in this undernourished adolescent model at Day 90 and 130 of gestation. Singleton pregnancies were established and ewes were offered an optimal control (C, n = 14) or low (L [0.7 x C], n = 21) dietary intake. Seven ewes receiving L intakes were switched to C intakes on Day 90 of gestation (L-C). Fetal body weight (P<0.01) and glucose concentrations (P<0.03) were reduced in L versus C pregnancies by Day 130, while L-C group values were intermediate. Placental cellular proliferation, gross morphology and mass were independent of maternal nutrition at both Day 90 and 130. In contrast, capillary area density in the maternal caruncular portion of the placentome was reduced by 20% (P<0.001) at both stages of gestation in L compared with C groups. Caruncular capillary area density was equivalent in the L and L-C groups at Day 130. Placental mRNA expression of five key angiogenic ligands or receptors increased (P < 0.001) between Day 90 and 130 of gestation. VEGFA mRNA expression was higher (P<0.04) in L compared with C and L-C pregnancies at Day 130, but otherwise gene expression of the remaining angiogenic factors and receptors analyzed was unaffected by maternal intake. Undernourishing the pregnant adolescent dam restricts fetal growth independent of changes in placental mass. Alterations in maternal placental vascular development may however play a role in mediating the previously reported reduction in maternal and hence fetal nutrient supply.
Key words:
Female Reproductive Tract •
Pregnancy •
Placenta •
Progesterone
