hCG reduces leptin release in the dual in vitro placenta perfusion model

Background: High maternal hCG levels were found in preeclampsia and in conditions of fetal growth retardation. Since leptin may be involved in the pathophysiology of preeclampsia and fetal growth we are interested in the effect of hCG on placental leptin release and general placental function.

Aim: Investigation of the effect of hCG on placental function and leptin release.

Material & Methods: 21 placentas at term; dual in vitro placenta perfusion in three groups: A: control; B: hCG conc. 5000 mIU/mL; C: hCG conc. 10.000 mIU/mL. Hormone release rates were measured after 3h and 6h of perfusion. Determination of hCG- and leptin- release; and glucose consumption, lactate production, creatinine transfer (controls for normal placental function).

Results: Leptin release decreased significant and dose dependent after addition of hCG: Difference between total leptin release rates after 3h and after 6h of perfusion (Median) A: +128 pg/g/min; B: +65 pg/g/min; C: –467 pg/g/min, p<0.05. We found also a significant higher lactate production rate in group B and C versus the control group. Creatinin permeability was also significant higher in group B and C versus A.

Conclusion: We could demonstrate a significant inhibitory influence of hCG on leptin release and an increasing effect on lactate production and creatinine permeability in the dual in vitro placenta model. Therefore high hCG levels could increase permeability and energy metabolism in pathologic pregnancies. The decrease in leptin release under the influence of hCG supports the hypothesis of a set of redundant placental hormones with similar functions to sustain the development of the fetus.