The villous stroma of the human placenta

Placental tissue expresses many lymphatic markers. The current study was undertaken to examine if D2-40/podoplanin, a lymphatic endothelial marker, was expressed in the human placentas, and how it is altered developmentally and pathologically. We studied D2-40/podoplanin and VEGFR-3 expressions in placentas from normotensive pregnancies at different gestational ages and in placentas from women with clinically defined preeclampsia. D2-40 expression in systemic lymphatic vessel endothelium served as a positive control. Protein expression for D2-40, VEGFR-3, and β-actin were determined by Western blot in placentas from normotensive (n=6) and preeclamptic (n=5) pregnancies. Our results show that D2-40/podoplanin was strongly expressed in the placenta, mainly as a network plexus pattern in the villous stroma throughout gestation. CD31 was limited to villous core fetal vessel endothelium and VEGFR-3 was found in both villous core fetal vessel endothelium and trophoblasts. D2-40/podoplanin expression was significantly decreased, and VEGFR-3 significantly increased in preeclamptic placental tissues compared to normotensive placental controls. Placental villous stroma is a reticular-like structure, and the localization of D2-40 to the stroma suggests that a lymphatic-like conductive network may exist in the human placenta. D2-40/podoplanin is an O-linked sialoglycoprotein. Although little is known regarding biological functions of sialylated glycoproteins within the placenta, placental D2-40/podoplanin may support fetal vessel angiogenesis during placenta development and reduced D2-40/podoplanin expression in preeclamptic placenta may contribute to altered interstitial fluid homeostasis and impaired angiogenesis in this pregnancy disorder.

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“…Placental villous stroma is a unique channel-like structure16. It consists of a network of cells and fibers with fetal vessels.…”

Section: Discussionmentioning

confidence: 99%

“…It consists of a network of cells and fibers with fetal vessels. Within the stroma, it forms a fluid compartment with Hofbauer cells suspended in the interspaces16. Mesenchymal and matrix channels provide a path for Hofbauer cells to patrol the villous core.…”

Section: Discussionmentioning

confidence: 99%

D2-40/podoplanin expression in the human placenta

Wang

Sun

et al. 2011

Placenta

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“…Factors that potentially support the capillaries and resist dilatation include vimentin filaments within the endothelial cells, and the surrounding basement membrane containing type IV collagen, laminin and fibronectin (Jones & Fox 1991). Externally, collagen fibres encircle the capillaries, but these are notably absent in the vicinity of sinusoids (Kaufmann et al 1977; Burton 1987).…”

Section: Discussionmentioning

confidence: 99%

The effects of maternal vascular pressure on the dimensions of the placental capillaries

Karimu

Burton

1994

BJOG

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Objective The study sought stereological evidence for the sluice flow phenomenon in the human term placenta. Design Two series of experiments were conducted on Caesarian delivered placentae. In both, two fetal arteries were cannulated and perfused. In the first series, five placentae were perfusion‐fixed under arterial pressures of 40 mmHg and 60 mmHg, and an external pressure of 10 mmHg in the intervillous space. In the second series, five placentae were perfusion‐fixed at arterial pressures of 70 mmHg and 90 mmHg with an external pressure of 30 mmHg. Stereological estimates relating to the size of the capillaries and the thickness of the villous membrane were then made. Results In each series, as the arterial pressure rose, there was an increase in the volume fraction and surface area of the fetal capillaries, and a concomittant decrease in the mean thickness of the villous membrane. These changes were negated as the external pressure rose, indicating the importance of the pressure differential between the capillary lumen and the intervillous space in determining the dimensions of the fetal capillaries. Conclusions The study demonstrated that placental capillaries are elastic and hence deformable. If a sufficiently high pressure is generated in the intervillous space, they may therefore be compressed. This may explain the increase in umbilical vascular resistance demonstrated by doppler studies in pregnant women scanned in the supine position. In this situation the venous drainage from the intervillous space is believed to be impeded by the gravid uterus compressing the inferior vena cava.

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“…The fibroblasts link up to form a network of canals that feed into the extra-embryonic coelom. These canals contain placental macrophages termed Hofbauer cells (Burton, 1987;Castellucci et al, 2000;Kaufmann et al, 1977). Because Hofbauer cells are the only immune cells in the placenta Fig.…”

Section: Other Placental Cellsmentioning

confidence: 99%

Development of the human placenta

2019

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The placenta is essential for normal in utero development in mammals. In humans, defective placental formation underpins common pregnancy disorders such as pre-eclampsia and fetal growth restriction. The great variation in placental types across mammals means that animal models have been of limited use in understanding human placental development. However, new tools for studying human placental development, including 3D organoids, stem cell culture systems and single cell RNA sequencing, have brought new insights into this field. Here, we review the morphological, molecular and functional aspects of human placental formation, with a focus on the defining cell of the placentathe trophoblast.

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The villous stroma of the human placenta

Cited by 69 publications

References 20 publications

D2-40/podoplanin expression in the human placenta

D2-40/podoplanin expression in the human placenta

The effects of maternal vascular pressure on the dimensions of the placental capillaries

Development of the human placenta

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