Co-expression of cytokeratins and vimentin by highly invasive trophoblast in the white-winged vampire bat, Diaemus youngi, and the black mastiff bat, Molossus ater, with observations on intermediate filament proteins in the decidua and intraplacental trophoblast

Abstract

Histological and immunocytochemical studies of gravid reproductive tracts obtained from the white-winged vampire bat (Diaemus youngi) and the black mastiff bat (Molossus ater) have established that both species develop unusually invasive trophoblast. This is released by the developing discoidal haemochorial placenta, expresses both cytokeratins and vimentin, and invades the myometrium and adjacent tissues (including the ovaries) via interstitial migration within the walls of maternal blood vessels. Hence, this trophoblast is noteworthy for the extent to which it undergoes an epithelial-mesenchymal transformation. In Molossus, it originates from the cytotrophoblastic shell running along the base of the placenta, is mononuclear, and preferentially invades maternal arterial vessels serving the discoidal placenta. This trophoblast may have a role in dilatation of these vessels when the discoidal placenta becomes functional. In Diaemus, the highly invasive trophoblast appears to originate instead from a layer of syncytiotrophoblast on the periphery of the placenta is multinucleated, and vigorously invades both arterial and venous vessels. During late pregnancy, it becomes extensively branched and sends attenuated processes around many of the myometrial smooth muscle fibres. In view of its distribution, this trophoblast could have important influences upon myometrial contractility and the function of blood vessels serving the gravid tract. Other aspects of intermediate filament expression in the uteri and placentae of these bats are also noteworthy. Many of the decidual giant cells in Molossus co-express cytokeratins and vimentin, while the syncytiotrophoblast lining the placental labyrinth in Diaemus late in pregnancy expresses little cytokeratin.

Vimentin and Epithelial-Mesenchymal Transition in Human Breast Cancer – Observations in vitro and in vivo

“…Up-regulated vimentin expression was shown to be associated with invasive cells during the development and growth of the placenta [Walter and Schonkypl, 2006]. EMT has also been described in maternal invasion of the intermediate trophoblasts in humans [Haigh et al, 1999] and bats [Badwaik et al, 1998]. …”

Embryonic Staging System for the Black Mastiff Bat,Molossus rufus(Molossidae), Correlated With Structure‐Function Relationships in the Adult

“…that existing on the island of Trinidad) (Rasweiler, 1988;Badwaik et al, 1998) opens the door to much more probing studies of significant reproductive, developmental and evolutionary problems. It provides a means of more accurately characterizing synchronized or seasonal breeding patterns in the wild.…”

“…The available evidence indicates that the Trinidadian population of M. rufus that provided breeding stock for this study is reproductively synchronized, and that some of the females may carry two pregnancies per year in quick succession (Rasweiler, 1988;Badwaik et al, 1998). The reproductive biology of M. rufus has also been extensively studied under controlled conditions in captivity (Rasweiler, 1987(Rasweiler, , 1988(Rasweiler, , 1990a(Rasweiler, ,b, 1991a(Rasweiler, ,b, 1992(Rasweiler, , 1993Badwaik et al, 1998), revealing this species to be an interesting model for studies of the biology of menstruation, trophoblastic growth and differentiation, and placental morphogenesis.…”

“…The reproductive biology of M. rufus has also been extensively studied under controlled conditions in captivity (Rasweiler, 1987(Rasweiler, , 1988(Rasweiler, , 1990a(Rasweiler, ,b, 1991a(Rasweiler, ,b, 1992(Rasweiler, , 1993Badwaik et al, 1998), revealing this species to be an interesting model for studies of the biology of menstruation, trophoblastic growth and differentiation, and placental morphogenesis. During its menstrual cycle, M. rufus also exhibits, within its uterus, the most pronounced example of physiological (nonpathological) angiogenesis thus far observed in any adult mammal (Rasweiler, 1991a).…”

Reproductive adaptations to a large‐brained fetus open a vulnerability to anovulation similar to polycystic ovary syndrome

“…Molossus ater delays development of an invasive placenta until late in gestation. Following implantation, initial development of a diffuse, endotheliochorial placenta results in only superficial penetration of the uterine endometrium until it is replaced by the development of a more invasive, hemochorial placenta relatively late in gestation (Badwaik et al, 1998;Rasweiler, 1992). Based on comparisons of reproductive strategies in bats, Rasweiler has suggested that menstruation in each of the two bat families may have evolved separately from a nonmenstruating ancestor (Raisweiler, 1991b;Rasweiler and de Bonilla, 1992).…”