Variation in composition of the intervillous space lining in term placentas of mothers with pre-eclampsia.

OBJECTIVE(S): To define composition of chorionic plate and test effects of pre-eclampsia on basal plate composition. STUDY DESIGN: Retrospective cohort study where distinct area fractions were measured in: healthy term chorionic plate (CP: n = 11), healthy placental basal plate (n = 11), mild pre-eclamptic basal plate (n = 10) and severe pre-eclamptic basal plate (n = 11). RESULTS: CP lining is partly endothelial. Mean anchoring villus (AV)/acellular (NS) basal plate area ratio decreased in pre-eclampsia (p = 0.048). There was a decreasing trend with increasing disease severity. Basal plate endothelial cell proportion was not significantly lower in severe pre-eclampsia than in healthy or mild pre-eclamptics. CONCLUSION(S): An inverse relationship between the proportions of fibrin and anchoring villi indicates that increased basal plate fibrin deposition and reduced basal plate materno-fetal anchoring area are part of pre-eclamptic disease progression. Endothelium lining intervillous surfaces may originate from circulating maternal endothelial progenitor cells.

Immunofluorescence confocal laser scanning microscopy and immuno-electron microscopic identification of keratins in human materno-foetal interaction zone.

We show here that at least 5 keratin proteins are present in villous trophoblast and the same 5 in extravillous trophoblast. A further 14 tested were undetectable in these tissues. In contrast, 10 of the 19 keratins tested were present in amniotic epithelium. The marking of amniotic epithelium on the one hand, as distinct from villous and extravillous trophoblast on the other, can be achieved using 5 keratins (K4, 6, 13, 14 and 17) with a mixture of positive and negative discrimination that is expected, in combination, to be highly sensitive. All the specific keratins identified in trophoblast were apparently up-regulated on the pathway to extravillous trophoblast. Co-ordinated differentiation at the molecular expression level is indicated by this finding. The relevant keratins are K5, 7, 8, 18 and 19. Specific keratins have been identified that are down-regulated in villous trophoblast in pre-eclamptic pregnancy. This difference between healthy and pre-eclamptic chorionic villous trophoblast keratin expression was statistically significant in 4 out of the 5 keratins. This was not the case for the extravillous trophoblast at the immunofluorescence confocal level but significant differences were obtained using immunogold electron microscopy. We suggest that the villous trophoblast in pre-eclamptic placentae is cytoskeletally weaker with respect to the filaments made from these specific proteins and that this is one reason why, in pre-eclampsia, trophoblast is deported in greater quantity than in healthy placentae.