Cyclical changes in the ultrastructure of the normal human endometrial stromal cell

Morphology of the human endometrium in the peri-implantation period

Although the histology and ultrastructure of the human endometrium are well documented, it is clear that morphometry can reveal subtle changes in cellular biology, especially when combined with suitable sampling and dating of the specimen. These changes reflect functional events, such as protein secretion, which may be studied using the endometrial flushing technique. Although it is likely that further insights into the basic cell physiology of the reproductive tract will result from the use of appropriate in vitro models, the role of endometrial biopsy for clinical monitoring remains essential.

Chorioallantoic placenta formation in the rat: I. Luminal epithelial cell death and extracellular matrix modifications in the mesometrial region of implantation chambers

On days 7 and 8 of pregnancy, mesometrial regions of rat gestation sites were examined by light microscopy and transmission electron microscopy to determine what changes occur before the chorioallantoic placenta forms in that region. By day 7, gestation sites contained a uterine lumen mesometrially and an antimesometrial extension of the uterine lumen, the implantation chamber. The implantation chamber consisted of a mesometrial chamber between the uterine lumen and the conceptus, an antimesometrial chamber that contained the conceptus, and a decidual crypt antimesometrial to the conceptus. Stromal cells that formed the walls of the implantation chamber were closely packed decidual cells, while those that surrounded the uterine lumen were loosely arranged. Late on day 7, a portion of the epithelium lining the mesometrial chamber was degenerating, but this area of initial degeneration was never adjacent to the antimesometrial chamber. By early day 8, most of the epithelial cells lining the mesometrial chamber were degenerating and were being sloughed into the chamber lumen. Although degeneration of these epithelial cells morphologically resembled necrosis, it was precisely controlled, since adjacent epithelial cells lining the uterine lumen remained healthy. The space that separated the denuded luminal surface of the mesometrial chamber from underlying decidual cells became wider and was occupied by an extracellular matrix rich in cross-banded collagen fibrils. Decidual cell processes, that earlier had penetrated the basal lamina beneath healthy epithelial cells, protruded into this matrix and penetrated the basal lamina at the luminal surface. By late day 8, large areas of denuded chamber wall were covered with decidual cell processes, little remained of the basal lamina, and cross-banded collagen fibrils were scarce in the area occupied by decidual cell processes. During the times studied, uterine tissues that formed the walls of the mesometrial chamber were not in direct contact with the conceptus. This study indicates that trophoblast does not play a direct role in epithelial degeneration, basal lamina penetration, or extracellular matrix modifications in the mesometrial region of implantation chambers where part of the chorioallantoic placenta forms, although trophoblast may be required to trigger or modulate some of the changes.

The effects of steroids on the fine structure of the endometrium

This brief review illustrates the lack of ultrastructural studies on human endometrium, particularly on well-dated material from normal, fertile women. The glandular epithelium, with its triad of unusual organelles in the early luteal phase, poses fascinating problems in cell biology and, probably for this reason, has attracted the most work. Many problems in reproductive biology, in uterine pathology and in the study of unexplained infertility are crying out for detailed study of the luminal epithelium, the stroma and the blood vessels. If this review, by highlighting the gaps in our knowledge, stimulates research into these areas, it will have been successful.

An immunohistochemical study of human endometrial extracellular matrix during the menstrual cycle and first trimester of pregnancy

Changes in the organisation and composition of extracellular matrix in human endometrium during the menstrual cycle and early pregnancy have been assessed by immunofluorescence. Amongst interstitial components, type-III and type V-collagens and fibronectin are present in endometrial stroma throughout the menstrual cycle as well as in first trimester decidua. Type V-collagen epitopes are masked early in the cycle, but become accessible in first trimester decidua. Type VI-collagen is abundant in endometrium in the proliferative phase, but is progressively lost in the secretory phase and decidua, in which it is retained only in blood vessel walls. Vitronectin is present in some blood vessels in decidua. Decidualising stromal cells also produce basement membrane components (type IV-collagen, laminin, heparan sulphate proteoglycan and a glycoprotein family recognised by monoclonal antibody G71) and these become organised into a pericellular aura.

Endometrial morphology in stimulated in vitro fertilization cycles and after steroid replacement therapy in cases of primary ovarian failure

Endometrial morphology and ultrastructure are studied in 17 spontaneous, 23 stimulated, and 18 artificial cycles in cases of primary ovarian failure. Normal light-microscopic aspect was found, but impaired development of nucleolar channel system and stronger intercellular junction have been observed by electron-microscopic studies in stimulated cycles with relative excess of luteal estrogen. Normal glandular maturation can be obtained in patients with premature menopause, given adequate steroid replacement, but an abnormally dense fibrocytic aspect of the stroma is characteristic of the first treatment cycles.

Müllerian clear cell carcinofibroma of the uterine corpus

A case of homologous Müllerian clear cell carcinofibroma occurring in the uterine corpus of a 71-year-old woman is described. The classification, histogenesis and possible biological behaviour of this unique tumour are briefly discussed.

Endometrial granulocytes in proliferative endometrium

Endometrial granulocytes were found in significant numbers in proliferative, hyperplastic and carcinomatous endometrium. The significance of this observation is discussed.