Altered villus vessel fibronectin in preeclampsia

Extracellular Matrix Influences Gene Expression and Differentiation of Mouse Trophoblast Stem Cells

Trophoblast stem (TS) cells were first isolated from the mouse placenta; however, little is known about their maintenance and niche in vivo. TS cells, like other stem cells, have a unique microenvironment in which the extracellular matrix (ECM) is a component. Placental pathology is associated with ECM change. However, how these changes and the individual ECM components impact the maintenance or differentiation of TS cells has not been established. This study identified which ECM component(s) maintain the greatest expression of markers associated with undifferentiated mouse trophoblast stem (mTS) cells and which alter the profile of markers of differentiation based on mRNA analysis. mTS cells cultured on individual ECM components and subsequent quantitative polymerase chain reaction analysis revealed that laminin promoted the expression of markers associated with undifferentiated TS cells, fibronectin promoted gene expression associated with syncytiotrophoblast (SynT) layer II cells, and collagen IV promoted the expression of genes associated with differentiated trophoblast. To investigate whether pathological placental ECM influenced the expression of genes associated with different trophoblast subtypes, the mouse model of streptozotocin (STZ)-induced pancreatic β cell ablation and diabetes was used. Female mice administered STZ (blood glucose ≥300 mg/dL) or control (blood glucose ≤150 mg/dL) were mated. Placental pathology at embryonic day (E)14.5 was confirmed with reduced fetal blood space area, reduced expression of the pericyte marker αSMA, and decreased expression of ECM proteins. mTS cells cultured on ECM isolated from STZ placenta were associated with reduced expression of undifferentiated mTS markers and increased expression of genes associated with terminally differentiated trophoblast [Gcm-1 and SynA (SynT) and junctional zone Tpbpa and Prl2c2]. Altogether, these results support the value of using ECM isolated from the placenta as a tool for understanding trophoblast contribution to placental pathology.

Expression patterns of two serine protease HtrA1 forms in human placentas complicated by preeclampsia with and without intrauterine growth restriction

Preeclampsia (PE) and intrauterine growth restriction (IUGR) are pregnancy-specific disorders that have in common abnormal placental implantation, a marked proliferation of villous cytotrophoblastic cells and focal necrosis of the syncytiotrophoblast. Several studies show an ischemic placenta with a high-resistance vasculature, which cannot deliver an adequate blood supply to the feto-placental unit. The cause of PE is a matter of debate, but recently studies in mice suggest that the primary feto-placental lesions are sufficient to initiate the disease. HtrA1, a member of the family of HtrA proteins, is a secreted multidomain protein with serine protease activity. It is expressed in first and third trimester of gestation. In specimens from the first trimester of gestation, immunostaining for HtrA1 is generally found in both layers of villous trophoblast, syncytiotrophoblast and cytotrophoblast. Cytoplasm of extravillous trophoblast and extracellular matrix of cell islands and cell columns are labeled for HtrA1. Specimens from third trimester of gestation show a more intense positivity for HtrA1 in the syncytiotrophoblast than in cytotrophoblast. The extravillous trophoblast and the decidual cells, is positive for HtrA1. The purpose of this study is to investigate the expression pattern of HtrA1 in placentas from PE without IUGR (maternal PE) and with IUGR (fetal PE) by quantitative western blotting and immunohistochemistry. By quantitative western blotting analysis we observed a significant upregulation of approximately 30 kDa HtrA1 form in PE. Differently, we detected a significant total HtrA1 down-regulation in PE-IUGR. Moreover, immunostaining for HtrA1 was positive in the villous trophoblast, in the syncytial knots and irregularly in the fetal vessel walls in PE placentas while immunostaining for HtrA1was present particularly in the syncytial knots in PE-IUGR placentas. In conclusion, we suggest that the approximately 30 kDa HtrA1 form can be correlated to maternal PE while that the significant down-regulation of total HtrA1 can be correlated to placental PE. These HtrA1 alterations could be considered as possible markers to discriminate placental PE from maternal PE.

Hemostasis and diagnosis of preeclampsia

The diagnosis of preeclampsia, with all of its consequences, is at times difficult to establish, especially when the patient has underlying chronic hypertension and is not known from prior prenatal care visits. Many screening tests have been proposed. These should be sensitive, relatively specific, easy to perform, of low cost, and have a reasonable interval from prediction to disease onset. Laboratory assays would obviously be useful. We evaluated hemostasis tests for the diagnosis of preeclampsia, and compared fibronectin, antithrombin III and alpha 2-antiplasmin in 48 preeclamptics and 86 control nulliparas. Receive operator characteristic (ROC) curve analysis suggested that fibronectin is the most effective of these tests. A similar analysis comparing the results of previous studies using serum iron, angiotensin infusion, urinary calcium/creatinine ratio, the rollover test and uric acid suggested a possible role for fibronectin in the diagnosis of preeclampsia. While not ideal, there seems to be, at present, no other, easy to perform laboratory test that outperforms fibronectin in predicting preeclampsia.

Increased plasma levels of ED1+ cellular fibronectin precede the clinical signs of preeclampsia

To evaluate alterations in fibronectin homeostasis in preeclampsia we measured the plasma concentrations of fibronectin bearing an extra type III domain in 33 preeclamptic and 36 control patients at varying gestational ages. This fibronectin variant is concentrated in the endothelium of blood vessels and has been shown to be released at sites of vascular injury. In addition, total circulating fibronectin levels, composed primarily of hepatic-derived fibronectin lacking the extra type III domain, were also determined. Significant elevations in the average circulating concentrations of fibronectin with an extra type III domain (5.5 micrograms/ml [95% confidence interval, 4.7,6.2] versus 3.2 micrograms/ml [95% confidence interval, 2.9,3.5]; p = 0.0001) as well as total fibronectin (387 micrograms/ml [95% confidence interval, 357,417] versus 327 micrograms/ml [95% confidence interval, 305,348]; p = 0.036) were observed in preeclamptic versus control patients. Significant elevations in fibronectin levels with an extra type III domain occurred in the first trimester before clinical evidence of preeclampsia. In addition, multivariate logistic regression demonstrated a 5.4-fold increase in the risk of preeclampsia with each 1 microgram/ml elevation in concentration of fibronectin with an extra type III domain. These findings lend support to the hypothesis that endothelial-vascular injury is a primary event in the genesis of preeclampsia.