Leptin and neuropeptide Y gene expression in human placenta:: Ontogeny and evidence for similarities to hypothalamic regulation

The objective of the present study was to examine the impact of preeclampsia on the relation of leptin and neuropeptide Y (NPY) gene expression in human placenta. A second goal was to monitor the change of leptin messenger RNA (mRNA) with increasing gestational age. Placental tissue was obtained from 17 premature deliveries, 18 term deliveries, and 10 mothers with preeclampsia. Gene expression of leptin, NPY, and two housekeeping genes (beta-actin and glyceraldehyde-3-phosphate dehydrogenase was quantified using real-time PCR. The leptin/beta-actin mRNA ratio was significantly higher in specimens of patients with preeclampsia than in those of gestational age-matched controls (0.63 +/- 0.23 vs. 0.09 +/- 0.04 relative U (RU); P = 0.03). NPY/beta-actin mRNA was significantly reduced in the preeclampsia group (0.003 +/- 0.001 us. 0.026 +/- 0.008 RU in controls; P = 0.01). The NPY/leptin ratio was 0.11 +/- 0.09 for preeclamptic placenta samples and 1.7 +/- 0.6 RU for the controls (P = 0.02). The leptin/beta-actin ratio was significantly lower in placenta from premature deliveries than in term deliveries (0.02 +/- 0.004 us. 0.12 +/- 0.05 RU; P = 0.01). Similar results were obtained for normalization to glyceraldehyde-3-phosphate dehydrogenase mRNA. Our data suggest an increase of placental leptin production with gestational age. In patients with preeclampsia, elevated leptin expression goes along with suppressed NPY expression. This resembles hypothalamic regulation.