J.L. Stevenson

Placental biglycan expression is decreased in human idiopathic fetal growth restriction

Fetal growth restriction (FGR) is a leading cause of perinatal morbidity and mortality. The majority of FGR cases are idiopathic and are associated with placental insufficiency, which can result from placental thrombosis. Evidence suggests that Dermatan Sulfate (DS) is an important anti-coagulant in placentae of uncomplicated pregnancies. This study hypothesised that the expression of biglycan proteoglycan, a source of DS, is decreased in idiopathic FGR placentae compared with placentae from uncomplicated pregnancies. This study aimed to determine biglycan mRNA, protein expression and spatial distribution in idiopathic FGR placentae compared with the placentae from gestation-matched controls. Biglycan mRNA expression, protein expression and spatial distribution was determined in 26 idiopathic FGR-affected placentae and 27 placentae from gestation-matched controls (27-40 weeks gestation) using real-time PCR, immunoblotting and immunohistochemistry, respectively. Mean biglycan mRNA expression was significantly decreased in FGR placentae compared with control placentae (2.87 +/- 0.55, (n = 26) vs. 4.48 +/- 0.85, (n = 27); t-test p = 0.01). FGR placentae demonstrated a trend towards decrease in mean biglycan protein expression compared with control placentae (0.86 +/- 0.22 (n = 9, FGR) vs, 1.9 +/- 0.56 (n = 7, control) p = 0.07). Biglycan immunoreactivity was detected in endothelial cells and sub-endothelial cells of the perivascular region of fetal capillaries. Semi-quantitative analyses demonstrated a significant decrease in immunoreactive biglycan in FGR placentae compared with control placentae (51.1 +/- 19.3 vs, 500.7 +/- 223, n = 6, p < 0.001). This is the first study to demonstrate decreased biglycan expression in idiopathic FGR placentae compared to gestation-matched controls. Reduced biglycan expression may contribute to placental thrombosis within the fetal vasculature, and may contribute to the pathogenesis of idiopathic FGR.

Calreticulin in human pregnancy and pre-eclampsia

Pre-eclampsia is a disorder of human pregnancy that involves pregnancy-induced maternal hypertension and proteinuria. Evidence indicates that pre-eclampsia involves widespread activation of maternal endothelial cells. Calreticulin is a ubiquitously expressed, multi-functional protein that has been shown to have both pro- and anti-inflammatory effects on cultured endothelial cells in vitro and in whole animals. In order to clarify the role of this protein in normal human pregnancy and in pre-eclampsia, this study has measured expression of calreticulin in maternal blood and in placenta in patients with pre-eclampsia and in control pregnancies. There was a significant increase (approximately 5-fold) in calreticulin in plasma in term pregnant women compared with women who were not pregnant. There was no difference, however, in calreticulin in plasma from women who were sampled at first trimester, second trimester and at term. In addition, there was a significant increase (approximately 50%) in calreticulin in plasma from pre-eclamptic women compared to controls. Calreticulin mRNA and protein expression in placenta were not changed between pre-eclampsia and control pregnancies. These novel results indicate that calreticulin is increased in peripheral maternal blood early in pregnancy and remains elevated throughout normal gestation and that there is a further increase in calreticulin in pre-eclampsia.

Placental CLIC3 is increased in fetal growth restriction and pre-eclampsia affected human pregnancies.

Chloride intracellular channel (CLIC) proteins constitute a subgroup of the glutathione-S-transferase (GSTs) superfamily. In humans, the CLIC family of proteins consists of six members, designated CLIC 1-6, which have a conserved C-terminal 240 residue module and one major transmembrane domain. CLIC proteins regulate fundamental cellular processes including regulation of chloride ion concentration, stabilization of cell membrane potential, trans-epithelial transport, regulation of cell volume and stimulation of apoptotic processes in response to cellular stress. Previously, we described the expression profile of a member of the CLIC family of proteins, CLIC3, in human placentae and fetal membranes. In the current study, we determined CLIC3 expression in placentae from pregnancies complicated with either fetal growth restriction (FGR, n=19), pre-eclampsia (PE, n=16) or both FGR and PE combined (n=12) compared to gestation-matched controls (n=13) using real-time PCR and a CLIC3 specific immunoassay. Significantly increased CLIC3 mRNA and protein were detected in placental extracts from pregnancies with FGR, PE and PE with FGR compared to controls. Our results suggest that increased expression of CLIC3 may play a role in abnormal placental function associated with the human pregnancy disorders FGR and PE.

No change in calreticulin with fetal growth restriction in human and rat pregnancies

INTRODUCTION Calreticulin is a ubiquitously expressed protein that was detected in the circulation and is significantly increased in maternal blood during human pregnancy compared to the non-pregnant state. Calreticulin is further increased in the plasma of women with the pregnancy-related disorder pre-eclampsia compared to normotensive pregnancy. The aims of this study were to compare calreticulin in human pregnancy with calreticulin in rat pregnancy, and to compare calreticulin during fetal growth restriction with normal control pregnancies. METHODS Women were recruited who either had normal pregnancies or had pregnancies complicated with fetal growth restriction; maternal blood samples and placentas were collected. Blood was also taken from women who were not-pregnant. Growth restriction was induced in pregnant rats by uterine vessel ligation; blood and placental samples were collected. Blood was also taken from non-pregnant rats. Western blot was used to quantify the placental expression of calreticulin and the concentrations of calreticulin in plasma. RESULTS Although calreticulin was significantly increased in maternal plasma during human pregnancy compared to the non-pregnant state; it did not increase in plasma during rat pregnancy. These results suggest that there may be differences in the role of extracellular calreticulin in human compared to rat pregnancy. Calreticulin was not significantly altered in either placental extracts or maternal plasma in both the human and rat pregnancies complicated by fetal growth restriction compared to gestational matched control pregnancies. CONCLUSION This study found that there was no change in calreticulin during human pregnancy complicated with fetal growth restriction or when growth restriction is induced in rats.