An Ultrastructural Study of Epithelium Differentiation in the Human Fetal Fallopian Tube

Abstract

The epithelial structure of the developing human fetal Fallopian tube has been studied systematically by parallel light, transmission and scanning electron microscopy. The specimens for this study were collected from spontaneous abortions at the 14th, 18th, 20th and 22nd weeks and from cases of intrauterine fetal death at the 24th and 31st weeks (hydrocephalus). The epithelium lining the wall of the female genital ducts was pseudostratified in a columnar fashion. It consisted of differentiating ciliated and microvillous cells and some degenerating elements. Microvillous cells – by far the most abundant in the early phases of tubal development – often showed a solitary cilium. Ciliated elements, though always less numerous than microvillous cells, were more densely concentrated on the developing fimbriae and at the uterotubal junction than in the ampulla. On the mucosal surface of the same regions, rounded intercellular holes delimited many crypts, from which ciliated elements sometimes sprouted. Notable aspects of cell proliferation and ciliogenesis were commonly observed and are likely to be related to circulating estrogens. These ultrastructural data indicate that the typical pattern of the adult oviduct is already sketched in fetal life. Furthermore, a strategic gathering of cilia was noted primarily at the sites of the developing oviduct, which will serve to mediate the passage of sperm and/or ova and promote fertilization in adult life.

Prenatal Bisphenol A Exposure Alters Epithelial Cell Composition in the Rhesus Macaque Fetal Oviduct

“…In humans and nonhuman primates, gross morphogenesis of the female reproductive tract is largely completed during the first trimester of pregnancy (Allen et al, 1982;Masse et al, 2009). The oviductal epithelium continues to differentiate to form ciliated and secretory cells starting at week 22 during human fetal development; at full term, the oviductal epithelium represents the pattern of an adult oviduct (Barberim et al, 1994;Konishi et al, 1987). In human and nonhuman primates, both the ciliated and secretory cells of the oviductal epithelium are responsive to ovarian steroid hormones and undergo changes over the menstrual cycle (Brenner et al, 1983;Patek et al, 1972a;Tollner et al, 2008).…”

Impact of Motile Ciliopathies on Human Development and Clinical Consequences in the Newborn

“…Of unknown function, motile cilia are present in the fetal esophagus at around week 16 of gestation but disappear by birth [ 23 , 24 ]. Multiciliated cells lining the fallopian tubes in females appear by approximately 14 weeks, but their known function is much later, establishing the fluid flow that carries oocytes [ 25 , 26 , 27 , 28 ]. The male sperm flagellum shares components with motile cilia, but only appear during spermatogenesis after the onset of puberty [ 29 , 30 , 31 ].…”

Repeated hyperstimulation affects the ultrastructure of mouse fallopian tube epithelium

“…Physiological/pathological changes of FT epithelium have been found in different species as rat [ 20 ], hamster [ 21 ], pig [ 22 ], goat [ 23 ] and horse [ 24 ]. Also, the ultrastructural features of mucosa and epithelial cells, such as the presence, distribution, and location of secretory and ciliated cells in the various portions of the human and murine FTs during the hormonal cycle have been described [ 25 , 26 ]. Interestingly, in mouse FTs the percentage of the ampullar epithelial cells and their proliferation rate were found to be estrus cycle-dependent [ 26 ].…”