Confocal laser scanning microscope study of terminal villi vessels in normal term and pre-eclamptic placentas

The aim of this study was to compare immunocytochemical confocal scanning laser microscopy measures of villus capillarization in control placentas with pre-eclamptic ones. Accordingly, placentas from normal term pregnancies (n=3) and cases of late-onset pre-eclampsia without intrauterine growth retardation (IUGR) featuring normal uterine artery Doppler (n=3) were analyzed by confocal scanning laser microscopy (CSLM), which is a powerful technique for obtaining three-dimensional reconstructions of any kind of blood vessels (arteries, veins, capillaries). A laser light beam is used in order to detect CD34 antibody-related immunofluorescence, which is a marker of endothelial cells. Villus capillarization was assessed by estimating the following parameters: number of pixels, mean, maximum and minimum immunofluorescence amplitude. Our results show a significant hyper-ramification of the capillary loop in pre-eclamptic placentas, featuring irregular profile and narrow lumina. Such findings support the hypothesis that several agents causing angiogenesis and vasoconstriction affect villus vessels in pre-eclamptic placentas, thus promoting a lasting condition of fetal hypoxia by decreasing endothelial surface and materno-fetal exchanges.