Circulating Corticotropin-Releasing Hormone mRNA in Maternal Plasma: Relationship with Gestational Age and Severity of Preeclampsia

Abstract

Higher concentrations of circulating nucleic acids (DNA and RNA) in maternal plasma/serum have been reported in pregnancies complicated by preeclampsia (PE) compared with controls matched for gestational age (1)(2)(3)(4)(5). Fetal and total DNA concentrations were also demonstrated to be directly correlated to both gestational age and to the severity of PE (6). Again, both hypertension and proteinuria (the two main symptoms for PE classification) are independently associated with an increase in circulating fetal DNA (6). Most studies, however, have had to rely on Y-chromosome loci, which can be used as fetus-specific markers for male fetuses. For this reason, the identification in maternal plasma of fetal-gender-independent markers, such as mRNA transcripts from genes expressed in fetal placenta, represented an important development in the field (4). The concentrations of mRNA for corticotropin-releasing hormone ( CRH ) in maternal plasma are significantly higher in PE than in controls (5), but no demonstration of relationships with gestational age and/or severity of PE have been reported. The aim of this study was to evaluate and quantify the relationships of the concentration of circulating CRH mRNA in maternal plasma with both gestational age and the severity of PE. We conducted a retrospective study in which the control group was 17 women with uncomplicated pregnancies (35% males) during the third trimester (median, 259 days since last menstrual period; minimum–maximum, 189–281 days). Controls were matched with 17 pregnancies (53% males) affected by PE at the time of blood collection (median, 256 days since last menstrual period; minimum–maximum, 181–279 days). PE was defined as gestational hypertension (systolic pressure >140 mmHg or diastolic blood pressure >90 mmHg on at least two occasions after 20 weeks of gestation) with proteinuria (>0.3 g/day). …