Comparative Placentation and Animal Models: Patterns of Trophoblast Invasion – A Workshop Report

Carter, Anthony Michael; Enders, Allen C.; Jones, Carolyn J.P.; Mess, Andrea; Pfarrer, Christiane; Pijnenborg, Robert; Soma, Hiroaki

doi:10.1016/j.placenta.2006.01.008

Cited by 48 publications

(45 citation statements)

References 10 publications

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“…comm. ), who has examined delivered placentae from the West Indian manatee, the species studied by Wislocki (1935), as well as the dugong (see Carter et al 2006b). Therefore, placentation in Sirenia must be regarded as endotheliochorial.…”

Section: Discussionmentioning

confidence: 99%

Placentation in the Amazonian manatee (Trichechus inunguis)

Carter

Moody

Ambrósio

et al. 2008

Reprod. Fertil. Dev.

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Abstract. Evidence from several sources supports a close phylogenetic relationship between elephants and sirenians. To explore whether this was reflected in similar placentation, we examined eight delivered placentae from the Amazonian manatee using light microscopy and immunohistochemistry. In addition, the fetal placental circulation was described by scanning electron microscopy of vessel casts. The manatee placenta was zonary and endotheliochorial, like that of the elephant. The interhaemal barrier comprised maternal endothelium, cytotrophoblasts and fetal endothelium. We found columnar trophoblast beneath the chorionic plate and lining lacunae in this region, but there was no trace in the term placenta of haemophagous activity. The gross anatomy of the cord and fetal membranes was consistent with previous descriptions and included a four-chambered allantoic sac, as also found in the elephant and other afrotherians. Connective tissue septae descended from the chorionic plate and carried blood vessels to the labyrinth, where they gave rise to a dense capillary network. This appeared to drain into shorter vessels near the chorionic plate. The maternal vasculature could not be examined in the same detail, but maternal capillaries ran rather straight and roughly parallel to the fetal ones. Overall, there is a close resemblance in placentation between the manatee and the elephant.

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Section: Discussionmentioning

confidence: 99%

Placentation in the Amazonian manatee (Trichechus inunguis)

Carter

Moody

Ambrósio

et al. 2008

Reprod. Fertil. Dev.

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“…Hence, trophoblast derived from the subplacenta is proposed as being responsible for the destruction of the maternal arterial endothelium during the formation of a haemochorial placenta, indicating an intense and deep invasion (Nanaev et al, '95;Kaufmann, 2004;Zaki et al, 2005) analogous to the cell columns of humans (Kaufmann and Castellucci, '97;Benirschke and Kaufmann, 2000;Pijnenborg et al, 2006). Thus, guinea-pig-like rodents appear as suitable animal models to study trophoblast invasion in comparison to human pregnancies (Kaufmann, 2004;Zaki et al, 2005;Carter et al, 2006). In contrast, rats and mice possess less deep endovascular and interstitial trophoblast invasion processes (Adamson et al, 2002;Caluwaerts et al, 2005;Vercruysse et al, 2006).…”

Section: Trophoblast Invasionmentioning

confidence: 99%

“…Hence, functional understanding of relevant structures was essential. Most importantly, an innovative hypothesis on the functional significance of the subplacenta is discussed: subplacental trophoblast is proposed as being responsible for the destruction of the maternal arterial endothelium during the formation of a haemochorial placenta (Kaufmann, 2004;Zaki et al, 2005;Carter et al, 2006).…”

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confidence: 99%

The subplacenta in Octodon degus and petromus typicus—two hystricognath rodents without significant placental lobulation

Mess

2006

J Exp Zool Pt B

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Until now, defining characters of hystricognath rodents have been the subplacenta and the lobulation of the main chorioallantoic placenta. However, recent studies have revealed hystricognaths without marked lobulation, which is a plesiomorphic condition of the group. The question thus arises whether the subplacenta of these taxa is structurally homologous to that of other hystricognaths. Therefore, subplacental morphology and ontogeny were investigated in Octodon and Petromus by conventional light and electron microscopy, and the stem species pattern of Hystricognathi was reconstructed by applying MacClade. The subplacentae of both species share important similarities with other hystricognaths. The organ develops early in gestation but degenerates towards term. It consists of folded layers of cellular and syncytial trophoblast, the latter enclosing maternal blood lacunae and electron-dense particles. Root-like syncytial outgrowths (syncytial streamers) and extraplacental trophoblast cells occur at the lateral and basal borders of the organ. Maternal vascularisation by blood lacunae within the subplacental syncytiotrophoblast is acquired early but lost during mid-gestation. Vascularisation by fetal vessels is established later. Fetomaternal exchange via blood circulation inside the subplacenta is unlikely to occur, since periods of maternal and fetal vascularisation show little overlap. In conclusion, the subplacentae of both species are regarded as homologous to other hystricognaths, comprising 18 character conditions that belong to their stem species pattern. Thus, the systematic unity of the group can be confirmed.

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“…Thus, invasion is very limited compared to humans [53]. In rats, invasion occurs between 15 and 18 days of pregnancy and is far more similar to the human situation [54]. Other animal species, such as the sheep and pig, possess an epitheliochorial placenta, where the placenta is apposed to the maternal endometrium, with no trophoblastic invasion or fusion of the 6 maternal and fetal membranes, although there are extensive increases in interdigitation and thinning of the 6 maternal and fetal cell layers during the course of gestation [49,50,52] Fig.…”

Section: Transplacental Transfermentioning

confidence: 99%

A perspective on the developmental toxicity of inhaled nanoparticles

Hougaard

Campagnolo

Chavatte‐Palmer

et al. 2015

Reproductive Toxicology

156

126

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This paper aimed to clarify whether maternal inhalation of engineered nanoparticles (NP) may constitute a hazard to pregnancy and fetal development, primarily based on experimental animal studies of NP and air pollution particles. Overall, it is plausible that NP may translocate from the respiratory tract to the placenta and fetus, but also that adverse effects may occur secondarily to maternal inflammatory responses. The limited database describes several organ systems in the offspring to be potentially sensitive to maternal inhalation of particles, but large uncertainties exist about the implications for embryo-fetal development and health later in life. Clearly, the potential for hazard remains to be characterized. Considering the increased production and application of nanomaterials and related consumer products a testing strategy for NP should be established. Due to large gaps in data, significant amounts of groundwork are warranted for a testing strategy to be established on a sound scientific basis.

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Comparative Placentation and Animal Models: Patterns of Trophoblast Invasion – A Workshop Report

Cited by 48 publications

References 10 publications

Placentation in the Amazonian manatee (Trichechus inunguis)

Placentation in the Amazonian manatee (Trichechus inunguis)

The subplacenta in Octodon degus and petromus typicus—two hystricognath rodents without significant placental lobulation

A perspective on the developmental toxicity of inhaled nanoparticles

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