Biochemical markers in the pathogenesis of preeclampsia: novel link between placental growth factor and interleukin-6

Preeclampsia (PE) is a multisystem disorder of pregnancy characterized by sudden onset of hypertension and proteinuria. The appearance and diagnosis of the disease remain elusive and the only treatment is the termination of pregnancy. The onset of the disease is preceded by a shift in the balance of the angiogenic and antiangiogenic proteins in the maternal circulation. We surmised that the assessment of the levels of these proteins during pregnancy could lead to a proper diagnosis of the disease. In this study, we determined the levels of angiogenic and antiangiogenic proteins and IL-6 in maternal circulation during normotensive and hypertensive pregnancy, including PE. Serum isolated from pregnant women during antenatal visits was used to determine the concentrations of these proteins. The levels of antiangiogenic proteins, sFlt-1 and sEng, were higher in hypertensive disorders [gestational hypertension (GH), mild PE, and PE] of pregnancy and were significantly higher for PE than for GH. The levels of sFlt-1 and sEng were higher in PE samples compared to those in GH and NT samples. These proteins may have contributed to increased blood pressure. The levels of PlGF were decreased in pregnant women having GH, mild PE, and PE. The levels of the inflammatory intermediate, IL-6, were increased in PE samples compared to those in the GH and normotensive samples. The evaluation of the altered levels of antiangiogenic and angiogenic proteins can be useful for diagnosis of PE.