Absence of In Vivo Generalized Pro-Inflammatory Endothelial Activation in Severe, Early-Onset Preeclampsia Rogier B. Donker, MSc, Grietje Molema, PhD, Marijke M. Faas, PhD, Cees G.M. Kallenberg, MD, PhD, Maria G. van Pampus, MD, PhD, Albertus Timmer, MD, PhD, and Jan G. Aarnoudse, MD, PhD OBJECTIVE: At present it is unclear whether endothelial activation is systematically present in preeclamp- sia or restricted to specialized vascular beds. Therefore, this study aimed to investigate the presence of generalized proinflammatory endothelial activation in severe, early-onset preeclampsia in vivo. METHODS: During caesarean section, biopsies were obtained from abdominal subcutaneous fat, abdom- inal fascia, and myometrium from 11 severe, early-onset preeclamptic and 19 healthy pregnant women. Prior to caesarean, section plasma levels of von Willebrand Factor (vWF), sVCAM-1, and C-reactive protein (CRP) were measured by ELISA. Consecutive cryostat sections were stained immunohistochemically for CD31, E-selectin, VCAM-1, and ICAM-1. For subcutaneous fat tissue, endothelial gene expression levels of E-selectin, VCAM-1, ICAM-1, endothelin-1 (ET-1), and endothelial nitric oxide synthase (eNOS) were quantified by real-time RT-PCR, using normalization to the endothelium-specific house- keeping genes CD31 and VE-cadherin. RESULTS: Plasma levels of vWF, sVCAM-1, and CRP were elevated in the preeclampsia group compared to the control group, indicating enhanced endothelial activation and inflammatory response in the severely diseased preeclamptic women. By immunohistochemical analysis, no E-selectin and VCAM-1 expression could be detected in, and no differences in endothelial ICAM-1 staining could be observed between the preeclampsia and the control group for all tissues studied. Endothelial gene expression levels of E-selectin, VCAM-1, ICAM-1, ET-1, and eNOS were comparable between the preeclampsia and control group. CONCLUSION: Protein and gene expression analysis of E-selectin, VCAM-1, ICAM-1, ET-1, and eNOS, key mediators involved in pro-inflammatory endothelial activation, could not identify endothelial activation in severe, early-onset preeclampsia in the tissues studied. However, elevated plasma levels of markers of endothelial activation and inflammation were observed. These results may suggest that in severe, early-onset preeclampsia pro-inflammatory endothelial cell activation is not a generalized phenomenon, but is likely restricted to (possibly organ-specific) specialized vascular beds. ( J Soc Gynecol Investig 2005;12: 518 –528) Copyright © 2005 by the Society for Gynecologic Investigation. T he multi-systemic syndrome of preeclampsia is charac- terized by the appearance of increased blood pressure and proteinuria in the second half of pregnancy. 1 Pre- eclampsia is frequently associated with intrauterine growth restriction, especially when severe and early at onset. 2 It is a leading cause of maternal mortality and increases perinatal morbidity and mortality considerably. 1 In the pathophysiology of preeclampsia, two stages are de- scribed: reduced placental perfusion and, secondarily, maternal systemic disease. 3 The first stage is characterized by abnormal placentation with reduced vascular invasion of trophoblasts and insufficient remodeling of spiral arteries, leading to reduced placental perfusion. 4 The second stage is the transduction of reduced placental perfusion into a maternal systemic inflam- matory syndrome in which systemic endothelial activation is considered the central component to which most clinical find- ings in preeclampsia can be attributed. 3,5 The maternal systemic inflammatory response is reflected by elevated serum levels of inflammatory markers including C- reactive protein (CRP), 6,7 interleukin (IL)-6, 8 and IL-8, 9 as well as by activation of leucocyte populations. 10 Pro-inflam- matory endothelial activation in preeclampsia is suggested by From the Departments of Obstetrics and Gynecology, Pathology and Laboratory Medicine, Medical Biology Section, Clinical Immunology, and Pathology, Groningen University Institute for Drug Exploration (GUIDE), University Medical Center Gro- ningen, Groningen, The Netherlands. Supported by the Groningen University Institute for Drug Exploration (GUIDE) and the Jan Kornelis de Cock Foundation, Project No. 04-06. Presented in part at the 52nd Annual Meeting of the Society for Gynecologic Inves- tigation, March 2005, Los Angeles, CA, and at the 2005 Congress of the European branch of the International Society for the Study of Hypertension in Pregnancy (ISSHP), June 2– 4, Rotterdam, The Netherlands. The authors thank Henk E. Moorlag, Department of Pathology and Laboratory Medicine, and Johan Bijzet, Department of Clinical Immunology, for expert technical assistance, and Sarah Buddeke and Patrick Vischjager for assistance in clinic and laboratory. Address correspondence and reprint requests to: Rogier B. Donker, MSc, Department of Obstetrics and Gynecology, Room Y4.240, University Medical Center Groningen, Hanzeplein 1, Postbox 30.001, 9700 RB, Groningen, The Netherlands. E-mail: r.b.donker@og.umcg.nl Copyright © 2005 by the Society for Gynecologic Investigation. 1071-5576/05/$30.00 Published by Elsevier Inc. doi:10.1016/j.jsgi.2005.06.007