Adverse adipose phenotype and hyperinsulinemia in gravid mice deficient in placental growth factor.
Pregnancy-induced metabolic changes are regulated by signals from an expanded adipose organ. Placental growth factor (PlGF), acting through vascular endothelial growth factor receptor-1, may be among those signals. There is a steep rise in circulating PlGF during normal pregnancy, which is repressed in gravidas who develop preeclampsia. PlGF-deficiency in mice impairs adipose vascularization and development. Here we studied young-adult PlGF-deficient (PlGF(-/-)) and wild-type mice on a high-fat diet in the nongravid state and at embryonic day (E) 13.5 or E18.5 of gestation. Litter size and weight were normal, but E18.5 placentas were smaller in PlGF(-/-) pregnancies. PlGF(-/-) mice showed altered intraadipose dynamics, with the following: 1) less blood vessels and fewer brown, uncoupling protein (UCP)-1-positive, adipocytes in white sc and perigonadal fat compartments and 2) white adipocyte hypertrophy. The mRNA expression of beta(3)-adrenergic receptors, peroxisome proliferator-activated receptor-gamma coactivator-1alpha, and UCP-1 was decreased accordingly. Moreover, PlGF(-/-) mice showed hyperinsulinemia. Pregnancy-associated changes were largely comparable in PlGF(-/-) and wild-type dams. They included expanded sc fat compartments and adipocyte hypertrophy, whereas adipose expression of key angiogenesis/adipogenesis (vascular endothelial growth factor receptor-1, peroxisome proliferator-activated receptor-gamma(2)) and thermogenesis (beta(3)-adrenergic receptors, peroxisome proliferator-activated receptor-gamma coactivator-1alpha, and UCP-1) genes was down-regulated; circulating insulin levels gradually increased during pregnancy. In conclusion, reduced adipose vascularization in PlGF(-/-) mice impairs adaptive thermogenesis in favor of energy storage, thereby promoting insulin resistance and hyperinsulinemia. Pregnancy adds to these changes by PlGF-independent mechanisms. Disturbed intraadipose dynamics is a novel mechanism to explain metabolic changes in late pregnancy in general and preeclamptic pregnancy in particular.
Hemmeryckx
Bianca
B
Department of Obstetrics and Gynecology, Health Canpus Gasthuisberg, Katholieke Universiteit Leuven, 3000 Leuven, Belgium.
van Bree
Rita
R
Van Hoef
Berthe
B
Vercruysse
Lisbeth
L
Lijnen
H Roger
HR
Verhaeghe
Johan
J
D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000098:blood supply / Q000378:metabolism; D000818:Animals; D004734:Energy Metabolism / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D005865:Gestational Age; D006946:Hyperinsulinism / Q000235:genetics*; D007333:Insulin Resistance / Q000235:genetics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009929:Organ Size / Q000235:genetics; D010641:Phenotype; D010920:Placenta / Q000033:anatomy & histology; D000072483:Placenta Growth Factor; D011247:Pregnancy; D011248:Pregnancy Complications / Q000235:genetics; D011257:Pregnancy Proteins / Q000235:genetics* / Q000378:metabolism; D011270:Pregnancy, Animal; D022722:Thermogenesis / Q000235:genetics
C000608037:Pgf protein, mouse; D011257:Pregnancy Proteins; D000072483:Placenta Growth Factor