Systemic and placental leptin and its receptors in pregnancies associated with obesity.

This study aimed to gain new insights into both systemic and placental leptin and its receptors, with reference to the maternal prepregnancy body mass index (BMI). Thus, 84 women (29 lean, 24 overweight, and 31 obese) were recruited and maternal, cord blood, and placental tissues collected prior to term labor. Plasma levels were measured by enzyme-linked immunosorbent assay and for placenta, immunohistochemistry and messenger RNAs (mRNAs) were quantitated. We confirmed that maternal leptin increased linearly as the soluble receptor decreased with BMI (P = .001). Fetal leptin increased with maternal BMI (P = .02) and birth weight (P = .006) and was higher in female infants (P < .001). Placental mRNA levels of leptin and its receptors showed no change in BMI. However, we show a significant (P = .043) linear increase in leptin in the placental vascular endothelial cells with maternal obesity, while leptin in syncytiotrophoblast showed no statistical change. Leptin receptors localized to syncytiotrophoblast and intravillous macrophages and were unchanged with BMI.