Decidual cells in the human ovary at term. I. Incidence, gross anatomy and ultrastructural features of merocrine secretion

Cutaneous Deciduosis: A Rare Cutaneous Lesion Mimicking Malignancy

ABSTRACT

Cutaneous deciduosis is an extremely rare condition that clinically presents as a nodular lesion in the skin as a scar or neoplasm. Histologically, this may pose a diagnostic challenge simulating malignant epithelioid neoplasms including sarcoma. Histologically, a nodular growth pattern of large monomorphic epithelioid cells is observed. The epithelioid cells in deciduosis can appear atypical with considerable nuclear pleomorphism, mimicking a malignancy. These features can be misinterpreted as a primary cutaneous or metastatic malignancy by dermatopathologists who are not familiar with gynecologic pathology. Failure to correctly diagnose this condition may result in unnecessary diagnostic studies for the patient. In this article, we report a case of cutaneous deciduosis in a 35-year-old woman with a cesarean scar. Histological examination revealed nodular proliferation of large epithelioid cells with pale eosinophilic cytoplasm and large nuclei with prominent nucleoli. Compressed atrophic slit-like glands resembling endometrial glands were present in some areas. Histopathological features of decidual cells, along with appropriate immunohistochemical studies, help establish the diagnosis and rule out other neoplastic mimics of deciduosis.

Expanded Chinese hamster organ and cell line proteomics profiling reveals tissue-specific functionalities

Chinese hamster ovary (CHO) cells are the predominant production vehicle for biotherapeutics. Quantitative proteomics data were obtained from two CHO cell lines (CHO-S and CHO DG44) and compared with seven Chinese hamster (Cricetulus griseus) tissues (brain, heart, kidney, liver, lung, ovary and spleen) by tandem mass tag (TMT) labeling followed by mass spectrometry, providing a comprehensive hamster tissue and cell line proteomics atlas. Of the 8470 unique proteins identified, high similarity was observed between CHO-S and CHO DG44 and included increases in proteins involved in DNA replication, cell cycle, RNA processing, and chromosome processing. Alternatively, gene ontology and pathway analysis in tissues indicated increased protein intensities related to important tissue functionalities. Proteins enriched in the brain included those involved in acidic amino acid metabolism, Golgi apparatus, and ion and phospholipid transport. The lung showed enrichment in proteins involved in BCAA catabolism, ROS metabolism, vesicle trafficking, and lipid synthesis while the ovary exhibited enrichments in extracellular matrix and adhesion proteins. The heart proteome included vasoconstriction, complement activation, and lipoprotein metabolism enrichments. These detailed comparisons of CHO cell lines and hamster tissues will enhance understanding of the relationship between proteins and tissue function and pinpoint potential pathways of biotechnological relevance for future cell engineering.

Macroscopic deciduosis in pregnancy is finally a common entity

OBJECTIVE

The primary aim of our study was to determine the prevalence of macroscopic deciduosis Found randomly in Cesarean sections and the secondary objective to determine the association with any obstetrical complications or adverse effects.

METHODS

This is a unicenter prospective study from 01/08/2011 to 01/02/2014. During the study period 307 consecutive Cesarean sections were performed with 31 biopsy proven cases of macroscopic deciduosis in the ovary, uterine and fallopian tube serosa.

RESULTS

The mean age of the patients was 31.2 ± 5.4 years (range 13-43), the mean Body Mass Index was 26.3 ± 5.8 (range 15-48)kg/m(2), the mean term of Cesarean was 270 ± 25 days, and the mean fetal weight was 3094 ± 809 g. The majority of patients were Caucasian (n=175, 57.0%). Patients with deciduosis had a greater BMI (28.4 ± 5.3 kg/m(2) vs 25.7 ± 5.8 kg/m(2), p<0.05). The presence of pain was more frequent in the deciduosis group (10.1%, OR 5.78, 95%, CI [2.41-13.87], p<0.001).

CONCLUSION

Deciduosis is a benign lesion during pregnancy that is not correlated with obstetrical complications. Our study has shown that this physiological phenomenon is more frequent that originally thought, being present in 10% of the Cesarean sections, and is associated with abdominal pain during pregnancy.

Imaging in gynecological disease. 10: Clinical and ultrasound characteristics of decidualized endometriomas surgically removed during pregnancy

OBJECTIVES

To describe the clinical history and ultrasound findings in women with decidualized endometriomas surgically removed during pregnancy.

METHODS

In this retrospective study, women with a histological diagnosis of decidualized endometrioma during pregnancy who had undergone preoperative ultrasound examination were identified from the databases of seven ultrasound centers. The ultrasound appearance of the tumors was described on the basis of ultrasound images, ultrasound reports and research protocols (when applicable) by one author from each center using the terms and definitions of the International Ovarian Tumor Analysis (IOTA) group. In addition, two authors reviewed together available digital ultrasound images and used pattern recognition to describe the typical ultrasound appearance of decidualized endometriomas.

RESULTS

Eighteen eligible women were identified. Median age was 34 (range, 20-43) years. Median gestational age at surgical removal of the decidualized endometrioma was 18 (range, 11-41) weeks. Seventeen women (94%) were asymptomatic and one presented with pelvic pain. In three of the 18 women an ultrasound diagnosis of endometrioma had been made before pregnancy. The original ultrasound examiner was uncertain whether the mass was benign or malignant in 10 (56%) women and suggested a diagnosis of benignity in nine (50%) women, borderline in eight women (44%), and invasive malignancy in one (6%) woman. Seventeen decidualized endometriomas contained a papillary projection, and in 16 of these at least one of the papillary projections was vascularized at power or color Doppler examination. The number of cyst locules varied between one (n = 11) and four. No woman had ascites. When using pattern recognition, most decidualized endometriomas (14/17, 82%) were described as manifesting vascularized rounded papillary projections with a smooth contour in an ovarian cyst with one or a few cyst locules and ground-glass or low-level echogenicity of the cyst fluid.

CONCLUSIONS

Rounded vascularized papillary projections with smooth contours within an ovarian cyst with cyst contents of ground-glass or low-level echogenicity are typical of surgically removed decidualized endometriomas in pregnant women, most of whom are asymptomatic.

A Case Presentation: Decidualized Endometrioma Mimicking Ovarian Cancer during Pregnancy

During pregnancy, masses that are larger than 5 cm and appearing in the Doppler ultrasonography as having increased blood flow, echoes of heterogeneous density, and containing solid components are suspicious for malignancy; however, differential diagnosis of decidualized endometriomas should also be considered. The patient was an 8 weeks pregnant primigravida. The ultrasonographic evaluation showed a cystic mass of size 65 × 57 mm in the left ovary that was well circumscribed, heterogeneous, with highly dense internal echo, and containing a solid component of size 8 × 14 mm. In the 12th week, the ultrasonographic examination revealed an increase in the size of the mass and increased arterial blood flow in the mass. The patient underwent surgery. It was observed that both ovaries were adherent in the Douglas pouch and that the left ovary contained an endometrioma of size 8cm. While the capsule was being peeled, lesions of soft density, with irregular surfaces, and with adhesion in the Douglas pouch were observed. The results of the frozen section revealed decidualized endometrioma and decidual structures. Even in pregnant women when adnexal masses are encountered and the ultrasonography, Doppler, MRI, and CA 125 level analysis still do not favor endometriosis, decidualized endometrioma should be considered in the differential diagnosis.

Decidualization of ovarian endometriosis during pregnancy mimicking malignancy

OBJECTIVE

The purpose of this series is to present deciduosis (the formation of extrauterine decidua) as one of the differential diagnoses of a malignant tumor during pregnancy.

METHODS

Two cases are described in which pregnant patients had a pelvic tumor. The lesions, which were diagnosed in the early second trimester, consisted of complex masses with an extensive blood supply and had a sonographic appearance of a malignant tumor. The high suspicion for malignancy necessitated surgical intervention.

RESULTS

During surgery, the lesions were observed to be of an ovarian origin with papillary excrescences covering their exterior. The lesions were excised and sent for histologic examination. The results showed a markedly decidualized endometriotic cyst in both cases.

CONCLUSIONS

This phenomenon is a diagnostic challenge and should be considered in the differential diagnosis of a malignant mass during pregnancy.

Selected miscellaneous ovarian lesions: small cell carcinomas, mesothelial lesions, mesenchymal and mixed neoplasms, and non-neoplastic lesions

This contribution will cover a variety of uncommon tumors and tumor-like lesions of the ovary that can be associated with a myriad of diagnostic problems for the pathologist. A few of these lesions are not specific to the ovary and may be more common in the uterus or even extraovarian sites, but the mere knowledge that they also occasionally occur in, or involve, the ovary will facilitate their recognition by the pathologist. In contrast, the entity considered first, the highly malignant small cell carcinoma of hypercalcemic type, is an enigmatic tumor unique to the ovary.

Life Cycle of Decidual Cells

The decisive events in the development of decidual cells (DC) are presented through examples of human and rodent decidua. Human decidua is formed by large decidual cells (LDC), endometrial granulated cells (eGC), and small decidual cells. The LDC form the main type of decidual membranes, which determine the morphological characteristics of the decidua as a tissue. Immediate precursor cells of LDC are located below the basement membrane of the uterine epithelium before and during implantation. At the next stage of differentiation, LDC acquire a spindle-like shape. Rodent LDC form an epithelium-like structure with gland properties at the terminal stage of differentiation. The single-cell structure of human decidua is a derivative of the epithelial organization of rodent decidua. Spindle-like rat LDC are characterized by a high level of protein, RNA, and DNA synthesis and by intensive proliferation. At the beginning of pregnancy, a cell proliferation predominates over cell loss. By Days 12-13 of rat pregnancy LDC loss reaches 80% per day. Terminally differentiated LDC (tLDC) disappear from decidua due to apoptosis. Apoptosis of tLDC and the exhaustion of their precursors account for the disappearance of LDC in the middle of rat pregnancy. Human term decidua is composed of living cells. Human LDC (hLDC) comprise the largest part of human decidual cells (hLDC). hLDC account for 60-90% of hDC but their relative amount can decrease to 35% in the case of significant cell loss under unfavorable conditions. A decrease of LDC is not accompanied by DC proliferation. The lack of ability of decidua to compensate for DC loss suggests DC is a growing type of cell population without cambial cells. LDC function largely by blebbing and budding. Human and rat endometrial granulated cells (eGC) are characterized by a low level of natural killer (NK) activity and a high level of natural suppressor (NS) activity. The combination of NK and NS properties is characteristic of the eGC immunoregulatory function. Other functions of decidua include control of inflammation and trophoblast growth and expansion in the uterus. The life span of decidual cells is limited by pregnancy.

Gross deciduosis peritonei obstructing labor: a case report and review of the literature

Gross deciduosis peritonei is a rare lesion characterized by the presence of grossly visible peritoneal decidual tissue in pregnant women; we present the clinicopathologic features of one such case. A 24-year-old, G4P1A2, Hispanic female underwent cesarean section at 39 weeks' gestation for dystocia related to pelvic masses. Multiple, light tan peritoneal masses involved the cul-de-sac, both ovaries, pelvic wall, omentum, and the large and small bowel. The intraoperative appearance suggested peritoneal carcinomatosis. A right ovarian mass was excised and biopsies were obtained from other sites. Microscopic examination showed the typical features of decidua in all of the lesions. Two weeks postoperatively, the patient was admitted with nausea and vomiting suggestive of a small bowel obstruction, which resolved after 2 days of medical treatment. After a postpartum visit at 5 weeks, the patient was lost to follow-up.

Genital talc exposure and risk of ovarian cancer

Epidemiologic studies have suggested an increased risk for ovarian cancer associated with the use of talcum powder in genital hygiene, but the biologic credibility of the association has been questioned. We conducted a population-based case-control study in eastern Massachusetts and New Hampshire involving 563 women with newly diagnosed epithelial ovarian cancer and 523 control women selected either by random digit dialing or through lists of residents. Use of body powders was assessed through personal interview and the exposure odds ratio (OR) for the use of talc in genital hygiene was calculated. Cases were more likely than controls (45% vs. 36%) to have used talc as a body powder in some manner, and the excess was confined to patients who used talc on the perineum directly or as a dusting powder to underwear or sanitary napkins. Relative to women who never used body powder or used it only in non-genital areas, the OR (and 95% confidence interval) associated with genital exposure to talc was 1.60 (1.18 and 2. 15) after adjustment for age, study location, parity, oral contraceptive use, body mass index and family history of breast or ovarian cancer. Exposure prior to rather than after a first livebirth appeared to be more harmful, and the association was most apparent for women with invasive serous cancers and least apparent for those with mucinous tumors. We conclude that there is a significant association between the use of talc in genital hygiene and risk of epithelial ovarian cancer that, when viewed in perspective of published data on this association, warrants more formal public health warnings.

Evaluation of a rapid strip test for insulin-like growth factor binding protein-1 in the diagnosis of ruptured fetal membranes

We evaluated the clinical usefulness of a new bedside test (PROM TEST) for insulin-like growth factor binding protein-1 (IGFBP-1) in the detection of ruptured fetal membranes (ROM). Cervicovaginal secretion was sampled between 15 and 37 weeks of gestation from asymptomatic women with apparently intact membranes and from women with clinically confirmed ROM, as well as from symptomatic women with suspected ROM based on history. IGFBP-1 in samples was detected with a dipstick based on immunochromatography. The test result was positive in 100% of cases with unequivocal ROM and in 5.3% of cases with apparently intact membranes. Furthermore, the PROM TEST was positive in 64 of 181 patients evaluated for suspected ROM based on history, but in whom the diagnosis could not be clinically confirmed at the initial evaluation. Fifty of the 64 women (78.1%) were delivered prematurely (< 37 weeks). Five of the 117 PROM-negative patients had elective cesarean section for reasons unrelated to ROM before 37 weeks and 10 of the remaining 112 patients (8.9%) had preterm delivery. Women with equivocal ROM and a positive test result had a 6.9-fold increased relative risk (95% confidence interval 4.2-11.4) of preterm delivery compared with women who had a negative result at the time of evaluation. Multiple logistic regression including PROM TEST result, contractions, vaginal bleeding and cervical changes indicated that a positive PROM TEST result was an independent predictor of preterm delivery (P = 0.0001). In summary, a positive PROM TEST result identifies ROM with high sensitivity and a negative result effectively excludes those with intact membranes. In patients with suspected but clinically unconfirmed ROM, the positive test result is associated with increased risk of preterm delivery, suggesting that microruptures of fetal membranes can also be detected by the PROM TEST.

Implantation and decidualization in rodents

This article reviews the main events of embryo-implantation and decidualization in rodents. In common laboratory rodents the embryo attaches to the uterine epithelial lining, usually on days 4 to 6 of pregnancy. A progressive degree of proximity between trophoblast and epithelium occurs until the epithelial cells undergo apoptosis and detach from the basement membrane. During the attachment stage, the spindle-shaped connective tissue cells that underlie the epithelium next to the embryos transform into polyhedral and closely packed decidual cells. Following the epithelial detachment and the breaching of the basement membrane the embryo is thus in direct contact with decidual cells. These cells accumulate organelles associated with synthesis of macro-molecules, intermediate filaments, and eventually lipid droplets and glycogen. Another remarkable feature of decidual cells is the establishment of gap and adherens intercellular junctions. Differentiation of fibroblasts into decidual cells advances antimesometrially and mesometrially, creating in the endometrium several regions of cells with different morphology. The whole phenomenon of decidualization which is normally triggered by the embryo can be artificially induced in pseudo-pregnant or hormonally-prepared animals with the use of diverse stimuli. The uterine epithelium is probably responsible for the transduction of the initial stimulus. Prostaglandins have been shown to be important in the induction of decidualization. More recently other substances such as leukotrienes, platelet-activating factor (PAF), and transforming growth factor (TGF) have been thought to play a role in induction. Much evidence points to prostaglandin production by the decidual cells. New proteins such as a luteotropic factor, desmin, and other molecules were shown to be produced after rat stromal cells undergo decidual transformation. The extracellular matrix of the mouse decidua contains very thick collagen fibrils. Mouse decidual cells are also very active in phagocytosing the thick fibrils, contributing to the remodeling and involution of the decidua that accompanies embryonic growth. Radioautographic data indicates that mouse decidual cells produce and secrete collagen and sulfated proteoglycans.

Pseudo-decidualization at the site of implantation in tubal pregnancy

The tissue from three tubal pregnancies at the site of implantation has been investigated with light and electron microscopy. Large seemingly "decidual" cells were found to be present between the anchoring villi and the tissue of the uterine tubes. These cells are or cytotrophoblastic column origin. Through discontinuities of the syncytiotrophoblast they migrate into the underlying tissue were they grow and synthesize large amounts of glycogen. It is suggested that these cells be named pseudo-decidual cells in order to distinguish them clearly from genuine decidual cells to which they only bear a resemblance on the light microscopical level. The fibrinoid present at the utero-placental interface in ectopic implantation cannot be found in ectopic implantation. From this fact it is deduced that fibrinoid is formed through the action of genuine decidual cells and therefore must be of maternal origin.

Current topic: structural responses of the primate endometrium to implantation

Morphological responses to implantation and pregnancy in the human and nonhuman primates include decidualization of the endometrial fibroblasts and accumulation of large numbers of large granular lymphocytes, formerly called endometrial granular cells, and may also include an epithelial plaque response and endothelial cell hypertrophy. Although stromal decidualization occurs in all species, it develops slower in macaques than in the human, and slower in the baboon than in the macaques. Cytologically, however, in all of these species there is extensive modification of the decidual cells by midgestation. Hypertrophy of luminal and gland neck epithelial cells is common in most monkeys and is also seen in the baboon, but has not been reported in humans. Large granular lymphocytes undergo changes in morphology during the first week after implantation in the rhesus monkey, the only species in which they have been studied in the immediate postimplantation period. Later in pregnancy many of the large granular lymphocytes are surrounded by decidual cells in this species. All of the responses can be elicited by trauma and appropriate hormonal conditions, but the epithelial plaque response forms first in the rhesus monkey and baboon. It is suggested that more complete fine structural and immunocytochemical studies of the different decidual regions at different gestational ages, combined with studies of the synthetic and antigenic nature of the different cell types, would allow determination of whether or not there are subpopulations of decidual cells in primates as well as suggesting possible functions of the cells in pregnancy.

Secondary müllerian system and endometriosis

The pathogenesis of endometriosis is controversial. The two principal histogenetic theories are (1) metastases of endometrial tissues to an ectopic location (metastatic theory) and (2) metaplastic development of endometrial tissue at the ectopic site (metaplastic theory). Studies on the development of the coelomic cavity and the müllerian duct, as well as expression of CA 125 during the fetal period and in the adult, strongly suggest that coelomic epithelium-related tissues and müllerian-derived epithelia of the adult have a shared embryologic ancestry. Many manifestations of müllerian-directed metaplasia suggest that tissues derived from the coelomic epithelium and its accompanying mesenchymal cells, referred to as the "secondary müllerian system," have the potentiality to differentiate into müllerian-directed epithelium and stroma. This metaplastic potentiality of the secondary müllerian system constitutes a basic concept in the pathogenesis of endometriosis.

Histology of the human endometrium: from birth to senescence

Embryologically, the human endometrium is of mesodermal origin, and constitutes the mucosal lining of the fused Mullerian ducts of the uterus. In the adult, premenopausal woman, the endometrium follows a precisely programmed series of morphologic and physiologic events, characterized by growth, secretory differentiation, and in the absence of conception, degeneration and regeneration. Proliferation, secretion and degeneration are confined to the upper functionalis layer, whereas the lower basalis layer is the seat of regenerative endometrium. In the postmenopausal years, absence of biologically significant estrogenic stimulation leads to progressive endometrial involution, from proliferative to inactive in the mid-50s to atrophy in the late-60s. Cyclic endometrial alterations are controlled by the ovarian estrogens and progesterone via their respective endometrial intranuclear receptors, and possibly other peptides and enzymes. They provide appropriate environment for the implanting conceptus. The intimate inter-relationship between endometrial structure/function and steroid hormones during the premenopausal period serves as an indicator of the hypothalamo-pituitary-ovarian axis as related to ovulatory states.

Secretory activity in the floor plate neuroepithelium of the developing human spinal cord: morphological evidence

The developing spinal cord at the cervical and thoracic levels in 14 human embryos ranging from Carnegie stages 14 to 20 were examined with the electron microscope. The floor plate-forming cells contained numerous cytoplasmic organelles, such as rough endoplasmic reticulum (ER), Golgi apparatus, and well-developed junctional complexes between the adjacent cells. Microvilli and cilia were numerous at the apical surface of neuroepithelial cells in the floor plate, but few were found in the lateral walls. Periodic acid-Schiff-positive substances were predominantly present in the neuroepithelial cells of the floor plate. In all specimens examined, multivesicular structures were observed in the floor plate neuroepithelium, but not in other regions of the spinal cord. The number of multivesicular structures appeared to increase with embryonic age. These structures contained numerous small and translucent vesicles within an electron-dense matrix; most vesicles were 40-70 nm in diameter. It appeared that the envelope of the multivesicular structures was first formed by the fusion of smooth ER-like cisterns, followed by invagination of the envelope by the vesicular contents. Presumably, the mature multivesicular structures were subsequently translocated to peduncular processes and their contents released into the central canal lumen in an exocytotic manner. This morphological evidence suggests that the floor plate cells of the spinal cord may have secretory activity during embryonic development.

Immunolocalization of extracellular matrix proteins and collagen synthesis in first-trimester human decidua

The extracellular matrix (ECM) of first-trimester human decidua was examined with indirect immunofluorescence using affinity-purified antibodies to human collagen types I, III, IV, V, laminin, and fibronectin. In addition, the validity of the classification "mesenchymal-epithelioid" for differentiated decidual cells was addressed using antibodies to the intermediate filament proteins, vimentin, a mesenchymal marker, and keratin, an epithelial marker. Biosynthesis of extracellular matrix components was examined by radiolabeling of decidual explants in culture with 3H-proline, followed by immunoprecipitations of synthesized proteins with collagen type-specific antibodies. Immunofluorescence showed decidual cells are embedded in an extensive network of collagen types I and III, and intracytoplasmic staining suggested synthesis of these collagens by the decidual cells. Collagen type IV and laminin localized in the external lamina which surrounds the differentiated decidual cell, and some fluorescence was evident in the peripheral cytoplasm. Immunoreactive collagen type V was observed in close association with the external lamina and in the peridecidual matrix. Fibronectin localized throughout the decidual ECM and in fibrillar and punctuate patterns in the decidual cell cytoplasm. Differentiated decidual cells retained a "mesenchymal" intermediate filament cytoskeleton containing an abundance of vimentin filaments, but very few, if any, keratin filaments. Collagen types I, III, V, and to a lesser extent, IV, were immunoprecipitated from the medium of decidual explants after 24 hours of culture, demonstrating in vitro synthesis and secretion of these collagens by first trimester human decidua.

Decidual cells in the human ovary at term: II. Morphometric analysis of cytoplasmic processes and organelles

Morphometric analysis of human ovarian decidual cells was performed with a Videoplan computer, and mean values were established for the area and perimeter of cellular processes and organelles. Two-hundred forty electron micrographs representing 160 cells were analyzed. The mean decidual cell area was 218.7 microns2, of which 34.5 microns2 was occupied by the nucleus (15.8% of the cytoplasmic area); the nucleus contained 1.74 micron2 of nucleolar material (0.8%). The endoplasmic reticulum occupied 13.63 microns2 (6.2%). Mitochondria occupied 7.3 microns2 (3.3%) and the Golgi network 5.49 microns2 (2.5%). Decidual secretory bodies occupied 0.91 micron2 (0.42%) and cytoplasmic processes 1.89 micron2 (0.94%). The remainder of the cytoplasm, containing inclusions and cytoskeleton, represented 71% of the cell area. Perimeter measurements indicated an average decidual cell was surrounded by 87.8 microns of plasma membrane. The mean nuclear membrane measured 28.3 microns (representing 32.3% of the plasma membrane, pm, or 4.1% of total cellular membranes, cm). Outer mitochondrial membranes measured 156.6 microns (178% pm, 23.5% cm); endoplasmic reticulum membranes measured 350.3 microns (400% pm, 52.6% cm); Golgi membrane measured 30.77 microns (35% pm; 4.5% cm) and membrane surrounding secretory bodies measured 9.8 microns (11.2% pm; 1.4% cm). A mean of 280 secretory bodies per ovarian decidual cell was calculated. The plasma membranes of evaginated cytoplasmic processes represented 22.3% of the total pm (19.6 microns or 2.9% cm). A mean of seven such processes was observed per 87.8 microns of plasma membrane (160/cell). These morphometric data provide a baseline for comparisons of human ovarian decidual cells with uterine decidua, in vivo and in vitro, as well as with decidual cells of other species.

Developmental changes in the fine structure of the chorion laeve (smooth chorion) of the rhesus monkey placenta

Developmental changes in the fine structure of the chorion laeve (smooth chorion) of the rhesus monkey were studied at two time periods during gestation: 1) Early (19-60 days of gestation), before the chorionic epithelium fuses with the parietal decidua, and 2) near term, when the fused chorioamnion has also fused with the parietal decidua. Early in gestation the chorionic epithelium consisted of columnar and cuboidal cells one or two layers thick. The apical border of the cells had microvilli and coated pits, and adjacent cells were joined by tight junctions and desmosomes. The chorionic epithelial cells during this early period contained numerous large vesicles and vacuoles of varying electron-density. The apical cytoplasm contained various small coated vesicles and tubules. Taken together these observations were interpreted as indicating a possible role for these cells in endocytosis or phagocytosis of substances from the uterine lumen; i.e., a potential role in histiotrophic nutrition during this early period. Late in gestation the trophoblastic cells were more irregular in shape. The cells contained abundant granular endoplasmic reticulum (ER) and mitochondria, and a well-developed Golgi complex, suggesting the cells were actively synthetic late in gestation. The numerous cytoplasmic vacuoles characteristic of the trophoblastic cells of early gestation were absent near term. Glycogen deposits and lipid droplets were moderately well-developed near term. Most of the cells were joined by desmosomes but wide intercellular spaces, unobstructed by any cell junctions, were frequently observed. This observation provides at least one explanation for the increase in permeability of the chorion laeve later in gestation. Cells of the parietal decidua associated with the chorion laeve were also examined. These cells generally had a well-developed granular ER and Golgi apparatus, and numerous mitochondria. Limited numbers of membrane-bounded secretory bodies, similar to those in human decidual cells, were also present.

Structural characteristics of the corpus luteum during implantation in the rhesus monkey (Macaca mulatta)

Corpora lutea were obtained from ten pregnant rhesus monkeys during implantation, and the ultrastructure of granulosa and theca lutein cells was characterized. Specimens were individually staged with regard to the extent of implantation and the relationship to the rise in circulating progesterone and estrogen which is characteristic of early pregnancy. Structural changes characteristic of granulosa lutein cells occurring during implantation included: change in form of endoplasmic reticulum from predominantly agranular tubules to predominantly granular cisternae; reduction in size and number of lipid droplets; increase in area occupied by the Golgi and increase in length of the cisternae of the Golgi complex; development of numerous microvillus-lined intracellular spaces; increase in numbers of membrane-bound dense bodies including peroxisomelike bodies, multivesicular bodies within lobopodia, and other lysosomelike bodies; and alterations of mitochondrial cristae. These changes were suggestive of the production of a secretory protein, rapid utilization of existing steroid precursor reserves for the production of progesterone, and a reduction in capability for steroid precursor accumulation and processing by granulosa lutein cells. Structural changes characteristic of theca lutein cells occurring during implantation included an increase in size and number of lipid droplets, an increase in agranular endoplasmic reticulum, and an increase in area occupied by the Golgi complex. These changes were suggestive of an increased capability for steroid precursor accumulation and processing, perhaps for estrogen production, by the theca lutein cells.

A freeze-fracture study of exocytosis and reflexive gap junctions in human ovarian decidual cells

Fine-structural features of ovarian decidual cells and their mode of secretion were examined by means of freeze-fracture microscopy. Unique cortical peduncular processes contained secretory vesicles within the expanded peduncle tip, the membrane-leaflets of which exhibited a particle-poor E face adjacent to the vesicle lumen and a P face containing a greater particle number. Exocytosis from attached peduncles involved release of vesicular profiles 40-55 nm in diameter; small particles 8.5-11.5 nm in diameter were also observed at degranulation sites. In fractures revealing the E face of the plasmalemma, cytoplasmic portals at the bases of peduncular stalks were distinguishable from endocytic vesicles. The frequent occurrence of reflexive gap junctions associated with peduncles was shown by freeze-fracture. However, there appeared to be no consistent spatial relationship between gap junctions, secretory peduncles, or sites of exocytosis. Freeze-fracture analysis of the topography of reflexive gap junctional profiles revealed that such gap junctions share basic similarities with intercellular gap jum particle-free aisles. The finding in the present study of reflexive gap junctions occurring between peduncles and the cell soma, as well as between peduncles, suggests that the original definitiof the same cell should be broadened to include any gap junctional specialization formed between portions of the plasma membrane of one cell.