Basic Structure of a Placental Villus

Burton, Graham J.

doi:10.1007/978-3-030-84725-8_6

Cited by 6 publications

(1 citation statement)

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“…Villous surface area is important in placental nutrient transfer, with decreases in surface area linked to human placental dysfunctions such as pre-eclampsia [ 29 ] and anaemia [ 30 ]. As a transporting epithelium, the apical and basal membranes of placental villous trophoblasts contain high densities of transporter proteins and are involved in active transport [ 31 ]. Therefore, our finding that equid villi have a higher surface area than human villi for a given volume may confer advantages to nutrient transfer.…”

Section: Discussionmentioning

confidence: 99%

Convergently evolved placental villi show multiscale structural adaptations to differential placental invasiveness

Laundon,

Sengers,

Thompson

et al. 2024

Biol. Lett.

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Despite having a single evolutionary origin and conserved function, the mammalian placenta exhibits radical structural diversity. The evolutionary drivers and functional consequences of placental structural diversity are poorly understood. Humans and equids both display treelike placental villi, however these villi evolved independently and exhibit starkly different levels of invasiveness into maternal tissue (i.e. the number of maternal tissue layers between placental tissue and maternal blood). The villi in these species therefore serve as a compelling evolutionary case study to explore whether placentas have developed structural adaptations to respond to the challenge of reduced nutrient availability in less invasive placentas. Here, we use three-dimensional X-ray microfocus computed tomography and electron microscopy to quantitatively evaluate key structures involved in exchange in human and equid placental villi. We find that equid villi have a higher surface area to volume ratio and deeper trophoblastic vessel indentation than human villi. Using illustrative computational models, we propose that these structural adaptations have evolved in equids to boost nutrient transfer to compensate for reduced invasiveness into maternal tissue. We discuss these findings in relation to the ‘maternal–fetal conflict hypothesis’ of placental evolution.

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Section: Discussionmentioning

confidence: 99%