Objective: The human placenta expresses a variety of vasoactive substances and neuropeptides, which play an important role in the regulation of placental blood flow in both the maternal and foetal compartment and are therefore of critical importance for foetal growth and development. Our study was planned to examine placental mRNA amounts of vasodilatory adrenomedullin (AM), calcitonin gene-related peptide (CGRP) and their receptors (AM-R and CGRP-R) in preeclampsia and HELLP syndrome (hemolysis, elevated liver enzymes, low platelets). These are severe maternal conditions leading to an altered uteroplacental and fetoplacental perfusion and a higher risk for foetal growth retardation, premature delivery, infant mortality, and even maternal death.
Study design: We included 17 patients with preeclampsia, four women with HELLP syndrome and 34 controls. After delivery, the mRNA levels of AM, AM-R, CGRP, CGRP-R, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and -actin were measured in placental villi and chorionic plates using quantitative real-time PCR.
Results: AM/-actin and AM/GAPDH mRNA ratios were significantly lower in placental villi in preeclampsia than in controls (P<0.05) as were CGRP/-actin and CGRP/GAPDH mRNA ratios in chorionic plates (P<0.05). Placental AM-R and CGRP-R mRNA amounts were unaffected.
Conclusion: Our data show a reduction of AM and CGRP mRNAs in contrast to unchanged mRNA levels of their receptors in placenta specimens of women with preeclampsia or HELLP syndrome.