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Introduction: The placental anticoagulant protein Annexin A5 (ANXA5) is a multifunctional protein that is highly expressed on the apical surfaces of syncytiotrophoblasts, and plays an important role in haemostatic regulations, maintaining blood fluidity of the placenta. The aim of this study was to investigate the expression of ANXA5 in pregnancies complicated by preeclampsia (PE)., Materials and Methods: Placental tissue samples were collected from 23 pregnancies with PE and 34 normal pregnancies. ANXA5 mRNA levels were measured by quantitative Real-Time PCR (qPCR), while ANXA5 protein expression was measured by Western Blot (WB) and immunohistochemistry., Results: ANXA5 mRNA expression in PE samples was lower than 1% of its expression in normal samples (mean ± SD: 0.002 ± 0.004 vs. 0.55 ± 0.38, p < 0.001), while ANXA5 protein levels in PE samples were approximately at 65% of the average normal expression (mean ± SD: 0.53 ± 0.30 vs. 0.81 ± 0.25, p=0.001). Immunohistochemical analysis also verified the above results, since PE placentas tended to have low labelling indexes (LIs), in contrast to controls which demonstrated high LIs (p=0.020). Statistical analysis of the WB data revealed that ANXA5 protein expression was increased in PE smokers vs. PE non-smokers (mean ± SD: 0.64 ± 0.23 vs. 0.41 ± 0.33, p=0.027)., Conclusions: These results suggest that ANXA5 downregulation could be part of the pathophysiology of PE and the possible impairment in coagulation processes, which are seen in pregnancies that demonstrate PE. Further studies may investigate whether ANXA5 could be used as a biomarker for the early detection of PE and for the prediction of its severity., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: The placental anticoagulant protein Annexin A5 (ANXA5) is highly expressed on the apical surfaces of syncytiotrophoblasts and plays an important role in maintaining blood fluidity in the placental circulation. We investigated the mRNA and protein expression of ANXA5 in placentas from pregnancies complicated by fetal growth restriction (FGR) compared with uncomplicated pregnancies., Materials and Methods: Placental tissue was collected from 18 pregnancies complicated by FGR and 16 pregnancies with a normal outcome. ANXA5 mRNA expression was quantified by Real-Time PCR (RT-PCR), and protein concentrations were measured by an enzyme-linked immunosorbent assay (ELISA)., Results: A decreased ANXA5 mRNA expression was observed in placenta samples from FGR-affected pregnancies compared to those from uncomplicated pregnancies. However, similar ANXA5 protein levels were measured in both specimen groups. No correlation was observed between ANXA5 mRNA and protein levels., Conclusions: Transcriptional ANXA5 down-regulation was demonstrated in FGR-affected pregnancies, although protein levels were similar in FGR-related placentas and controls. We can speculate that either recruitment of the protein from the bloodstream or increased apoptosis or post-transcriptional modifications occur, which affect ANXA5 protein levels in FGR-related placentas. Further studies are required to reveal the role of ANXA5 in FGR pathology., ((c) 2009 Elsevier Ltd. All rights reserved.)