Endoglin in HIV-associated preeclamptic placentae

To examine the placental immunoexpression of endoglin (Eng), in HIV-negative and HIV-positive normotensive (N- and N+) and preeclamptic (P- and P+) pregnancies at term, using immunohistochemistry and immunoelectron microscopy.

Strong Eng immunoreactivity was observed within endothelial cells, syncytio- and cyto-trophoblast cell populations. All extravillous trophoblast cells were immunopositive for Eng. Subcellularly, gold particles were immunolocalised within the endoplasmic reticulum, and mitochondria. Immunoexpression of Eng differed significantly between exchange (p = 0.02) and conducting villi (p < 0.001). A higher Eng immunoexpression was observed in both villi types of the preeclamptic compared to normotensive groups. Irrespective of pregnancy type (normotensive versus PE), there was no significant effect of HIV status on Eng immunoexpression within the exchange and conducting villi.

The immunostaining of Eng within the endothelial cells, syncytio-, cyto- and extravillous trophoblast cell populations of HIV-associated preeclamptic placentae is novel. Endoglin and its soluble component remains an area for dynamic placental exploration in preeclampsia development.