Search

Abstract: Placental development involves a series of events that depend on the coordinated action of proliferation, differentiation and invasion of trophoblasts. Studies on cell cycle related proteins controlling these events are fairly limited. It is still not fully determined how placental tissue proliferation is affected by intrauterine growth retardation (IUGR). Information on cell cycle related proteins that control these events is limited and how they are affected in IUGR is not fully understood. The aim of this study was to understand the role of cell cycle regulators in IUGR placentas and to determine the spatio-temporal immunolocalization of these cell cycle regulators in human IUGR and normal term placentas. Placental samples were stained immunohistochemically with PCNA, Ki67, cyclin D3, p27 and p57 antibodies and were examined by light microscopy. In all regions of IUGR placentas, PCNA, Ki67 and cyclin D3 staining intensities were statistically significantly decreased compared to normal controls. p27 staining intensity of the IUGR group was statistically significantly increased in villous parts and chorionic plates in comparison with the normal term placentas. Moreover, p57 staining intensity was statistically significantly increased in all parts of the IUGR group compared to controls. The observed placental abnormalities in IUGR placentas may be associated with arrest mechanisms affecting cell proliferation and cell cycle alterations in IUGR. [Copyright &y& Elsevier]

Abstract: Intrauterine growth restriction (IUGR) is a major clinical problem which causes perinatal morbidity and mortality. Although fetuses with IUGR form a heterogeneous group, a major etiological factor is abnormal placentation. Despite the fact that placental development requires the coordinated action of trophoblast proliferation and differentiation, there are few studies on cell cycle regulators, which play the main roles in the coordination of these events. Moreover it is still not determined how mechanisms of coordination of proliferation and differentiation are influenced by dexamethasone-induced IUGR in the placenta. The aim of the study was to investigate the spatial and temporal immunolocalization of proliferating cell nuclear antigen (PCNA), Ki67, p27 and p57 in normal and IUGR placental development in pregnant Wistar rats. The study demonstrated altered expressions of distinct cell cycle proteins and cyclin dependent kinase inhibitors (CKIs) in IUGR placental development compared to control placental development. We found reduced immunostaining of PCNA and Ki67 and increased immunostaining of p27 and p57 in the dexamethasone-induced IUGR placental development compared to control placental development. In conclusion, our data show that the cell populations in the placenta stain for a number of cell cycle related proteins and that these staining patterns change as a function of both gestational age and abnormal placentation. [Copyright &y& Elsevier]