RhoE Is Regulated by Cyclic AMP and Promotes Fusion of Human BeWo Choriocarcinoma Cells

Fusion of placental villous cytotrophoblasts with the overlying syncytiotrophoblast is essential for the maintenance of successful pregnancy, and disturbances in this process have been implicated in pathological conditions such as pre-eclampsia and intra-uterine growth retardation. In this study we examined the role of the Rho GTPase family member RhoE in trophoblast differentiation and fusion using the BeWo choriocarcinoma cell line, a model of villous cytotrophoblast fusion. Treatment of BeWo cells with the cell permeable cyclic AMP analogue dibutyryl cyclic AMP (dbcAMP) resulted in a strong upregulation of RhoE at 24h, coinciding with the onset of fusion. Using the protein kinase A (PKA)-specific cAMP analogue N6-phenyl-cAMP, and a specific inhibitor of PKA (14–22 amide, PKI), we found that upregulation of RhoE by cAMP was mediated through activation of PKA signalling. Silencing of RhoE expression by RNA interference resulted in a significant decrease in dbcAMP-induced fusion. However, expression of differentiation markers human chorionic gonadotrophin and placental alkaline phosphatase was unaffected by RhoE silencing. Finally, we found that RhoE upregulation by dbcAMP was significantly reduced under hypoxic conditions in which cell fusion is impaired. These results show that induction of RhoE by cAMP is mediated through PKA and promotes BeWo cell fusion but has no effect on functional differentiation, supporting evidence that these two processes may be controlled by separate or diverging pathways

Avaliação da hemorragia feto-materna em puérperas com indicação para ministração de imunoglobulina anti-D Evaluation of fetomaternal hemorrhage in postpartum patients with indication for administration of anti-D immunoglobulin

Avaliamos a ocorrência da hemorragia feto-materna entre 343 puérperas que receberiam profilaxia da aloimunização Rh com emprego de imunoglobulina anti-D. Realizamos o teste de roseta para triagem dos casos que necessitariam determinação quantitativa do volume de sangue fetal transferido para circulação materna, que foi então apurado pelo teste de Kleihauer-Betke (K-B). O teste de roseta apresentou resultado positivo em 22 casos (6,4%). Em cinco dessas amostras o teste de K-B não apontou hemorragia feto-materna (falso positivo do teste de roseta de 1,45%) e noutra a leitura do teste não foi conclusiva. Tivemos oito casos com volume apurado de hemorragia feto-materna < 10ml (2,3%), seis com hemorragia feto-materna entre 10 e 30ml (1,7%) e duas puérperas apresentaram transferência sangüínea feto-materna maior que 30ml (0,58%), necessitando suplementação além da dose padrão de anti-D. O teste de roseta dispensou 93,6% das pacientes da avaliação adicional da hemorragia feto-materna por método quantitativo.<br>This study evaluated fetomaternal hemorrhage (FMH) in 343 postpartum patients who required prophylaxis of Rh alloimmunization with anti-D immunoglobulin. The rosette test was applied to screen for patients needing quantitative determination of fetal blood transferred from the maternal circulation, which was then measured by the Kleihauer-Betke test (K-B). The rosette test was positive in 22 cases (6.4%). In five of these cases, K-B did not show fetomaternal hemorrhage (a 1.45% false-positive rate for the rosette test), and in one case the test was inconclusive. There were 8 cases with FMH < 10ml (2.3%), 6 cases with FMH from 10 to 30ml (1.7%), and two cases with FMH > 30ml (0.58%), requiring a supplementary dose of anti-D. The study concludes that following the rosette test, additional evaluation of FMH using a quantitative test was unnecessary in 93.6% of the cases