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Cited by 71High Altitude and HypoxiaPregnancy and preeclampsia studiesReproductive Physiology in Livestock

Term ovine placental vasculature: Comparison of sea level and high altitude conditions by corrosion cast and histomorphometry

Krebsa, C., Longob, L.D., Leiser, R.·1997·Placenta
DOI 10.1016/s0143-4004(97)90070-9
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Abstract

The placental vascular architecture differs significantly at high altitude from that at sea level in the human and guinea-pig. Four sheep between 137 and 140 days of gestation, kept near sea level throughout gestation, were used as a normoxic control group for comparison of the placental vasculature with 10 other ewes, kept at high altitude (3820 m above sea level; Barcroft Laboratory, White Mountain Research Station, CA, USA). Placentomes from both groups were prepared for histology and scanning electron microscopy of vascular corrosion casts. Singular perfusion of fetal placentae, as well as combined maternal/fetal injection was performed. The influence of long-term hypoxaemia was determined by qualitative and semi-quantitative evaluation of corrosion casts and histological sections. The fetal vessel casts show a distinct difference in the arrangement of vessels of all sizes in response to long-term hypoxaemia. In the control group, stem arteries and veins are straight and parallel. In contrast, this is much less evident in the hypoxaemic group because arterioles and venules branch off the stem vessels more frequently and in an irregular manner. This leads to a capillary bed that is much more dense due to increased branching and capillary coiling. These observations are confirmed by histomorphometry. In the fetal vessels of high altitude sheep placentomes, we observed a decreased number of vascular cross sections (21.6 +/- 4.7 SEM versus 27.7 +/- 4.0 SEM; P = 0.02). However, the average luminal size per cross section (77.9 +/- 10.5 microns2 SEM versus 59.4 +/- 7.4 microns2 SEM; P = 0.004) was increased at high altitude and the percentage of lumina of the total area (5.7 +/- 0.5 SEM versus 5.3 +/- 0.3 SEM; P = 0.09) indicated a trend towards an increase. In maternal vessels of high altitude placentomes, the number of vessel cross sections (6.5 +/- 0.7 SEM versus 6.0 +/- 0.5 SEM; P = 0.2) remained unchanged, whereas the average luminal size (1108 +/- 122 microns2 SEM versus 844 +/- 77 microns2 SEM; P < 0.001) and the percentage of lumina out of the total area (20.9 +/- 1.8 SEM versus 17.5 +/- 1.7 SEM; P < 0.001) were increased. The interhaemal distance appeared to be slightly but not significantly increased at high altitude. These findings indicate that at high altitude the sheep placenta develops an increased materno-fetal absorptive surface to help guarantee substance exchange.

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Crossref · 10.1016/s0143-4004(97)90070-9

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  • At high altitude, there are changes in the vasculature and blood flow on the fetal side of the placenta in both humans and sheep.

    “At high altitude, there are also changes in the vasculature and blood flow on the fetal side of the placenta in both humans and sheep (317, 431, 443).”

    From Placental Origins of Chronic Disease (2016) · cites this paper as [317]

  • In pregnant sheep at high altitude, the luminal cross sectional area, but not the number, of maternal vessels in the placentomes is increased, which results in a greater percentage area of maternal blood vessels and normal fetal growth.

    “In pregnant sheep at high altitude, the luminal cross sectional area, but not the number, of maternal vessels in the placentomes is increased, which results in a greater percentage area of maternal blood vessels and normal fetal growth (317, 437).”

    From Placental Origins of Chronic Disease (2016) · cites this paper as [317]

  • In neither mouse nor sheep is there evidence for thinning of the interhemal membrane in response to hypoxic conditions.

    “In neither of these species is there evidence for thinning of the interhemal membrane in response to hypoxic conditions (133, 317).”

    From Placental Origins of Chronic Disease (2016) · cites this paper as [317]

  • Similar increases in fetal vascularity are seen in ovine placentomes at high altitude, but, in contrast to the findings in the human placenta, these are accompanied by an increase in the total surface area of fetal-maternal contact for gas exchange.

    “Similar increases in fetal vascularity are seen in ovine placentomes at high altitude, but, in contrast to the findings in the human placenta, these are accompanied by an increase in the total surface area of fetal-maternal contact for gas exchange (317, 431).”

    From Placental Origins of Chronic Disease (2016) · cites this paper as [317]

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Authors
Krebsa, C., Longob, L. D., & Leiser, R.
Affiliations
  • Justus-Liebig-Universität Gießen (DE)
  • Loma Linda University (US)
Corresponding author
Krebsa, C.
Venue
Placenta
Publisher
Elsevier BV
Published
1997-01
Volume
18
Issue
1
Pages
43-51
ISSN
0143-4004 (ISSN-L)
DOI
10.1016/s0143-4004(97)90070-9
OpenAlex
W2037637848
Cited by
71
References
60
Citations by year
2025: 2 · 2021: 4 · 2020: 2 · 2019: 1 · 2018: 2 · 2017: 2 · 2016: 2 · 2015: 5 · 2014: 1 · 2013: 3 · 2012: 2
FWCI
2.44
Type
journal article
Language
en
Open access
closed
Licence
Locations
  • Placenta (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › High Altitude and Hypoxia
  • Health Sciences › Medicine › Obstetrics and Gynecology › Pregnancy and preeclampsia studies
  • Life Sciences › Agricultural and Biological Sciences › Agronomy and Crop Science › Reproductive Physiology in Livestock
Keywords
placental vasculature, high altitude, hypoxemia, fetal sheep, corrosion casts, histomorphometry, capillary network, vascular branching, gestation
MeSH terms
Altitude, Animals, Capillaries, Female, Fetus, Microscopy, Electron, Scanning, Placenta, Pregnancy, Sheep, Corrosion Casting

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