Influence of maternal undernutrition and overfeeding on cardiac ciliary neurotrophic factor receptor and ventricular size in fetal sheep

Intrauterine nutrition status is reported to correlate with risk of cardiovascular diseases in adulthood. Either under- or overnutrition during early to mid gestation contributes to altered fetal growth and ventricular geometry. This study was designed to examine myocardial expression of ciliary neurotrophic factor receptor α (CNTFRα) and its downstream mediator signal transducer and activator of transcription 3 (STAT3) on maternal undernutrition- or overnutrition-induced changes in fetal heart weight. Multiparous ewes were fed with 50% [nutrient-restricted (NR)], 100% (control) or 150% [overfed (OF)] of National Research Council requirements from 28 to 78 days of gestation (dG; term, 148 dG). Ewes were euthanized on Day 78, and the gravid uteri and fetuses recovered. Ventricular protein expression of CNTFRα, STAT3, phosphorylated STAT3, insulin-like growth factor I receptor (IGF-1R), and IGF binding protein 3 (IGFBP3) were quantitated using Western blot. Plasma cortisol levels were higher in both NR and OF fetuses, whereas plasma IGF-1 levels were lower and higher in NR and OF fetuses. Fetal weights were reduced by 29.9% in NR ewes and were increased by 22.2% in fetuses from OF ewes compared to control group. Nutrient restriction did not affect fetal heart or ventricular weights, whereas overfeeding increased heart and ventricular weights. Protein expression of CNTFRα in fetal ventricular tissue was reduced in OF group, whereas STAT3 and phosphorylated STAT3 levels were reduced in both NR and OF groups. Expression of IGF-1R and IGFBP3 was unaffected in either NR or OF group. These data suggested that, compared with maternal undernutrition, intrauterine overfeeding during early to mid gestation is associated with increases in fetal blood concentrations of cortisol and IGF-1, in association with ventricular hypertrophy where reduced expression of CNTFRα and STAT3 may play a role.