Apoptosis, bcl-2 expression, and proliferative activity in human endometrial stroma and endometrial granulated lymphocytes

Artificial intelligence deep learning model assessment of leukocyte counts and proliferation in endometrium from women with and without polycystic ovary syndrome

OBJECTIVE

To study whether artificial intelligence (AI) technology can be used to discern quantitative differences in endometrial immune cells between cycle phases and between samples from women with polycystic ovary syndrome (PCOS) and non-PCOS controls. Only a few studies have analyzed endometrial histology using AI technology, and especially, studies of the PCOS endometrium are lacking, partly because of the technically challenging analysis and unavailability of well-phenotyped samples. Novel AI technologies can overcome this problem.

DESIGN

Case-control study.

SETTING

University hospital-based research laboratory.

PATIENT(S)

Forty-eight women with PCOS and 43 controls. Proliferative phase samples (26 control and 23 PCOS) and luteinizing hormone (LH) surge timed LH+ 7-9 (10 control and 16 PCOS) and LH+ 10-12 (7 control and 9 PCOS) secretory endometrial samples were collected during 2014-2019.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Endometrial samples were stained with antibodies for CD8+ T cells, CD56+ uterine natural killer cells, CD68+ macrophages, and proliferation marker Ki67. Scanned whole slide images were analyzed with an AI deep learning model. Cycle phase differences in leukocyte counts, proliferation rate, and endometrial thickness were measured within the study populations and between the PCOS and control samples. A subanalysis of anovulatory PCOS samples (n = 11) vs. proliferative phase controls (n = 18) was also performed.

RESULT(S)

Automated cell counting with a deep learning model performs well for the human endometrium. The leukocyte numbers and proliferation in the endometrium fluctuate with the menstrual cycle. Differences in leukocyte counts were not observed between the whole PCOS population and controls. However, anovulatory women with PCOS presented with a higher number of CD68+ cells in the epithelium (controls vs. PCOS, median [interquartile range], 0.92 [0.75-1.51] vs. 1.97 [1.12-2.68]) and fewer leukocytes in the stroma (CD8%, 3.72 [2.18-4.20] vs. 1.44 [0.77-3.03]; CD56%, 6.36 [4.43-7.43] vs. 2.07 [0.65-4.99]; CD68%, 4.57 [3.92-5.70] vs. 3.07 [1.73-4.59], respectively) compared with the controls. The endometrial thickness and proliferation rate were comparable between the PCOS and control groups in all cycle phases.

CONCLUSION(S)

Artificial intelligence technology provides a powerful tool for endometrial research because it is objective and can efficiently analyze endometrial compartments separately. Ovulatory endometrium from women with PCOS did not differ remarkably from the controls, which may indicate that gaining ovulatory cycles normalizes the PCOS endometrium and enables normalization of leukocyte environment before implantation. Deviant endometrial leukocyte populations observed in anovulatory women with PCOS could be interrelated with the altered endometrial function observed in these women.

Uterine natural killer cells: Time for a re-appraisal?

The presence of unusual natural killer cells in human endometrium has been recognized for 30 years, but despite considerable research effort, the in vivo role of uterine natural killer (uNK) cells in both normal and pathological pregnancy remains uncertain. uNK cells may differentiate from precursors present in endometrium, but migration from peripheral blood in response to chemokine stimuli with in situ modification to a uNK cell phenotype is also possible. uNK cells produce a wide range of secretory products with diverse effects on trophoblast and spiral arteries which may play an important role in implantation and early placentation. Interactions with other decidual cell populations are also becoming clear. Recent evidence has demonstrated subpopulations of uNK cells and the presence of other innate lymphoid cell populations in decidua which may refine future approaches to investigation of the role of uNK cells in human pregnancy.

Absence of predictable long-term molecular effect of ulipristal acetate (UPA) on the endometrium

RESEARCH QUESTION

What are the effects of ulipristal acetate (UPA) on the expression of endometrial proliferation and maturation markers?

DESIGN

A total of 45 endometrium-containing blocks of hysterectomy samples from non-menopausal women with a diagnosis of moderate to severe symptoms of uterine fibroids: 14 women operated on at the end of a 3-month course of UPA; four women who had discontinued UPA treatment 1-12 months before surgery; 27 control unexposed samples (14 in the proliferative and 13 in the secretory phase). Immunohistochemical staining of Ki67, vascular endothelial growth factor-receptor 2 (VEGFR2), oestradiol receptor, progesterone receptor, interleukin-15 (IL-15), indoleamin-2,3-dioxygenase (IDO) and C-C motif chemokine ligand-2 (CCL2) markers were analysed in both endometrial compartments and layers.

RESULTS

Under UPA, oestradiol receptor and progesterone receptor expression is similar to the proliferative phase in both layers, although with a decrease in cell proliferation. IL-15, IDO and CCL2 expressions are similar to the proliferative phase, suggesting a progesterone-antagonist effect of UPA. VEGFR2 staining suggests a trend to a mixed agonist-antagonist effect. No significant difference is observed in the post-UPA proliferative phase group compared with the control group in both layers of the endometrium.

CONCLUSION

The effect of 3-month UPA treatment is mostly progesterone receptor antagonist-like. After treatment is discontinued, there are no signs of any long-term effects of this molecule on endometrial proliferation and maturation. Therefore, UPA may be administered to women willing to conceive in the short term without consequences for further implantation.

Lateral inhibition of Notch signaling in neoplastic cells

During normal development, heterogeneous expression of Notch ligands can result in pathway suppression in the signal-sending cell, a process known as lateral inhibition. It is unclear if an analogous phenomenon occurs in malignant cells. We observed significant induction of Notch ligands in glioblastoma neurospheres and pancreatic carcinoma cells cultured in low oxygen, suggesting that this phenomenon could occur around hypoxic regions. To model lateral inhibition in these tumors, the ligand Jagged1 was overexpressed in glioblastoma and pancreatic carcinoma cells, resulting in overall induction of pathway targets. However, when ligand high and ligand low cells from a single line were co-cultured and then separated, we noted suppression of Notch pathway targets in the former and induction in the latter, suggesting that neoplastic lateral inhibition can occur. We also found that repression of Notch pathway targets in signal-sending cells may occur through the activity of a Notch ligand intracellular domain, which translocates into the nucleus. Understanding how this neoplastic lateral inhibition process functions in cancer cells may be important in targeting ligand driven Notch signaling in solid tumors.

Deep Invasive Endometriosis Lesions of the Rectosigmoid May Be Related to Alterations in Cell Kinetics

OBJECTIVES

The aim of this study was to analyze cell kinetics through expression and apoptosis of topoisomerase 2-α (TOP2A), p53, and c-erb2 in rectosigmoid endometriotic lesions and in healthy endometrial tissue and to establish correlations between such findings and clinical data in patients with rectosigmoid endometriosis.

METHODS

Sixty patients with rectosigmoid endometriosis and 20 control women without endometriosis were included. Immunohistochemical assays were used to measure expression of TOP2A, p53, and c-erB-2. Apoptosis was quantified by directly counting the apoptotic bodies.

FINDINGS

The number of lesions was positively correlated with expression of TOP2A in the lesion. There was also significant correlation between the lesions' size and number and cell turnover index. Apoptosis index (AI) was the same for endometriosis lesions and eutopic endometrium. Expression of TOP2A was significantly lower in the endometriosis group compared to the controls.

CONCLUSIONS

Changes in cell proliferation but not in the AI in rectosigmoid endometriosis are indicative of an imbalance in cell kinetics that may lead to the development of the disease.

The Role of Uterine NK Cells in Normal Reproduction and Reproductive Disorders

The human endometrium contains a substantial population of leucocytes which vary in distribution during the menstrual cycle and pregnancy. An unusual population of natural killer (NK) cells, termed uterine NK (uNK) cells, are the most abundant of these cells in early pregnancy. The increase in number of uNK cells in the mid-secretory phase of the cycle with further increases in early pregnancy has focused attention on the role of uNK cells in early pregnancy. Despite many studies, the in vivo role of these cells is uncertain. This chapter reviews current information regarding the role of uNK cells in healthy human pregnancy and evidence indicating their importance in various reproductive and pregnancy problems. Studies in humans are limited by the availability of suitable tissues and the limitations of extrapolation from animal models.

Increased AKT or MEK1/2 activity influences progesterone receptor levels and localization in endometriosis

CONTEXT

Endometriosis is characterized by progesterone resistance and hyperactivity of the AKT and MAPK pathways. Kinases can cause posttranslational modifications of the progesterone receptor (PR) to influence cellular localization and protein stability.

OBJECTIVE

The objective of this study was to determine whether the increased AKT or MAPK kinase-1/2 (MEK1/2) activity observed in endometriotic stromal cells (OSIS) from ovarian endometriomas influences levels of PR protein. In turn, the effects of inhibiting AKT or MEK1/2 in the presence of the progestin R5020 on cell viability were investigated.

RESULTS

Inhibiting AKT with MK-2206 or MEK1/2 with U0126 for 24 hours in the absence of R5020 increased total and nuclear PRA and PRB protein levels in OSIS but not in eutopic endometrial stromal cells from disease-free patients from disease-free patients. MK-2206 and R5020 decreased OSIS viability and increased apoptosis. Trends toward decreased volumes of sc grafted endometriosis tissues were demonstrated with MK-2206 and progesterone.

CONCLUSIONS

Inhibition of AKT or MEK1/2 increased total and nuclear PR protein in OSIS. MK-2206 and R5020 decreased OSIS viability and increased apoptosis. The AKT and MAPK pathways may be potential molecular targets for the treatment of endometriosis.

[Interest of selective progesterone receptor modulators in endometriosis]

The SPRM (selective progesterone receptor modulators) are agonists and/or antagonists of progesterone receptor. They are responsible for anovulation, amenorrhea and a lower prostaglandin levels, which leads to an improvement in pain and regression of lesions in endometriosis. On the endometrium, a particular aspect, the progesterone receptor modulator-associated endometrial changes (PAEC), raises additional studies to verify its harmlessness. However, due to the lack of hypoestrogenism and metabolic effects with these drugs, it is very likely that the SPRM will in the near future an important place in the treatment of endometriosis.

The effects of ulipristal on Bax/Bcl-2, cytochrome c, Ki-67 and cyclooxygenase-2 expression in a rat model with surgically induced endometriosis

OBJECTIVE

To evaluate the effect of ulipristal on Bax/Bcl-2, cytochrome C, Ki-67 and cyclooxygenase-2 expression in surgically induced endometriosis in a rat model.

STUDY DESIGN

We conducted a prospective, randomized, controlled, experimental study at the Experimental Research Center of the Iuliu Hatieganu University of Medicine and Pharmacy in Cluj-Napoca, Romania. Endometriosis was induced in 40 female Wistar albino rats by transplanting two autologous fragments of uterine horn onto bowel mesentery. After a 4-week induction period, we formed two groups: the first group was treated with ulipristal (UPA+) for 8 weeks, while the second group was treated only with the vehicle used for ulipristal (UPA-). We measured the volumes and masses of the implants both before and after treatment. A pathologist examined the sections microscopically for histological hallmarks of endometriosis. Immunostaining for Bax/Bcl-2, cytochrome C, Ki-67 and cyclooxygenase-2 (COX-2) was assessed in both groups.

RESULTS

Ulipristal reduced the average implant volume and mass, indicating that the drug is effective (P=0.01). The treatment induced a greater than 50% reduction in the volume and mass of endometrial implants, and the histological findings correspond to this result. The overall Bax positivity rate was higher in the group treated with ulipristal (42.37% vs. 21.05% for UPA+ and UPA-, respectively) (P=0.0062). The overall Bcl-2 positivity rate was smaller in the group treated with ulipristal (15% vs. 40% for UPA+ and UPA-, respectively) (P=0.0593). The cytochrome C global positivity rate was 5% in the UPA- group and increased to 50% in the UPA+ treatment group (P<0.0001). The COX-2 positivity rate decreased from 75% in the UPA- treatment group to 10% in the UPA+ treatment group (P<0.0001) and the Ki67 positivity rate also decreased from 55% in the UPA- group to 10% in the UPA+ treatment group (P<0.0002).

CONCLUSIONS

Treatment with ulipristal contributed to the regression and atrophy of endometriotic lesions in rats. The immunohistochemical expression profiles of Bax/Bcl-2 and cytochrome C revealed a pro-apoptotic effect of ulipristal. We also observed a reduced cellular proliferation, indicated by a decrease in Ki-67 expression and an anti-inflammatory effect, shown by a decrease in COX-2 expression after treatment with ulipristal.

DBA-lectin reactivity defines mouse uterine natural killer cell subsets with biased gene expression

Endometrial decidualization, a process essential for blastocyst implantation in species with hemochorial placentation, is accompanied by an enormous but transient influx of natural killer (NK) cells. Mouse uterine NK (uNK) cell subsets have been defined by diameter and cytoplasmic granule number, reflecting stage of maturity, and by histochemical reactivity with Periodic Acid Schiff (PAS) reagent with or without co-reactivity with Dolichos biflorus agglutinin (DBA) lectin. We asked whether DBA- and DBA+ mouse uNK cells were equivalent using quantitative RT-PCR analyses of flow-separated, midpregnancy (Gestation Day [gd] 10) cells and immunohistochemistry. CD3E (CD3)-IL2RB (CD122)+DBA cells were identified as the dominant Ifng transcript source. Skewed IFNG production by uNK cell subsets was confirmed by analysis of uNK cells from eYFP-tagged IFNG-reporter mice. In contrast, CD3E-IL2RB+DBA+ uNK cells expressed genes compatible with significantly greater potential for IL22 synthesis, angiogenesis, and participation in regulation mediated by the renin-angiotensin system (RAS). CD3E-IL2RB+DBA+ cells were further divided into VEGFA+ and VEGFA- subsets. CD3E-IL2RB+DBA+ uNK cells but not CD3E-IL2RB+DBA- uNK cells arose from circulating, bone marrow-derived progenitor cells by gd6. These findings indicate the heterogeneous nature of mouse uNK cells and suggest that studies using only DBA+ uNK cells will give biased data that does not fully represent the uNK cell population.

Commitment of decidual haematopoietic progenitor cells in first trimester pregnancy

PROBLEM  The aim of this study was to investigate the phenotype and commitment of decidual haematopoietic progenitor cells (HPCs) in healthy pregnant women and in women with early miscarriage. METHOD OF STUDY  Peripheral blood and decidual tissue from healthy and pathological pregnant women were examined for HPCs and lymphoid progenitors using flow cytometric analysis. RESULTS  Compared with peripheral blood, we found a significant increase in decidual HPCs in both healthy pregnant women and women with spontaneous abortion. T/NK, natural killer (NK), gamma-delta and NKT cell progenitors were identified in all peripheral blood and decidual samples. In pathologic pregnant women, the ratios of decidual T/NK and NK cell progenitors were significantly increased compared with healthy pregnant controls. CONCLUSION  We demonstrated decidual cells with haematopoietic progenitor cell phenotype in human decidua. Increased levels of NK progenitors in the decidua of women with early spontaneous abortion suggest a dysregulation of this pathway that may contribute to pregnancy failure.

Uterine natural killer (uNK) cells and their missions during pregnancy: a review

Natural killer (NK) cells are lymphocytes of the innate immune system. The aim of this review is to describe the properties and roles of NK cells in the human uterus during pregnancy. Uterine natural killer cells (uNK) constitute a major lymphocyte population during early gestation in the uterus. The uterine natural killer cells are recognized owing to their CD56(bright), CD16(-), CD3(-) phenotype. Their number increases in the first trimester with a subsequent decline as pregnancy progresses. They have been shown to be closely associated with cells of the extravillous trophoblast (EVT) and spiral arteries. They play important roles in remodeling of the spiral arteries, control of trophoblast invasion and in the development of the placenta. Some studies have shown the number and repertoire of receptors of uNK differ between women with healthy pregnancies and those with pathologic pregnancies, such as pre-eclampsia or intrauterine growth retardation. During pregnancy, the cytotoxic characteristics of the uterine killer cells are not directed towards the fetus, and scientists continue to question and explore this phenomenon with increasing evidence that these cells may perform differing beneficial roles during pregnancy. Contrary to their previously suspected "hostile" characteristics, the uterine killer cells are considered to be "friendly" and appear to be essential and very important regulators of successful implantation and pregnancy.

Cells with haematopoietic stem cell phenotype in adult human endometrium: relevance to infertility?

BACKGROUND

Uterine lymphoid cell repertoires are specialized in order to meet the twin demands of successful pregnancy and local immunosurveillance. The possibility that some of these populations might differentiate locally from progenitor cells has been proposed.

METHODS

Endometrial tissue from women with a history of infertility as well as fertile controls was examined for haematopoietic stem cells (HSCs) and lymphoid progenitors using three-colour flow cytometry.

RESULTS

Significant populations of phenotypic HSCs (CD34+ CD45+ ) were detected in all samples, a high proportion of which co-expressed the differentiation marker CD45RA (45.7%), indicating ongoing differentiation. Almost 30% of uterine HSCs co-expressed CD56 and 44% co-expressed CD7, suggesting the presence of lymphoid progenitors. Small proportions expressed CD127 and CD122, receptors for interleukin (IL)-7 and IL-15, respectively. HSC numbers were similar in the endometrial samples from fertile and infertile women. However, the proportion co-expressing the natural killer (NK) antigen CD56 was significantly increased compared with HSCs found in the endometrium of fertile controls (P = 0.002).

CONCLUSIONS

This is the first demonstration of cells with an HSC phenotype in the human endometrium, and increased proportions of NK progenitors in endometrium of women with infertility suggests a dysregulation of this pathway that may contribute to infertility.

Caspase-3-mediated apoptosis and cell proliferation in the equine endometrium during the oestrous cycle

Cell proliferation and apoptosis are hormone-dependent physiological processes involved in endometrial growth and regression. The aims of the present study were: (1) to evaluate endometrial cell proliferation using proliferating cell nuclear antigen (PCNA) expression; (2) to evaluate the induction of endometrial cell death by the expression of active caspase-3 and the apoptotic phenotype visualised by DNA fragmentation; and (3) to relate these observations to endometrial tissue dynamics in the equine endometrium throughout the oestrous cycle. Endometria were assigned to follicular and luteal phases based on ovarian structures and plasma progesterone. Cell proliferation and active caspase-3-mediated apoptosis were expressed in both phases of the oestrous cycle. In the luteal phase, PCNA expression was higher than in the follicular phase. Highest PCNA activity was noted in the luminal and glandular structures. Active caspase-3 staining was increased in luminal epithelium and deep glandular cells during the luteal phase. However, in the follicular phase, stromal cells showed greater active caspase-3 expression. Only a few apoptotic endometrial cells were detected by terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling (TUNEL) and these cells were mostly present in luminal and glandular structures. A simultaneous increase in DNA, cell proliferation and protein synthesis was observed in the endometrium during the mid-luteal phase. This suggests that cell hyperplasia occurs at the time the histotroph is needed for eventual embryo nourishment.

BRCA1--a good predictive marker of drug sensitivity in breast cancer treatment?

There are currently only two predictive markers of response to chemotherapy for breast cancer in routine clinical use, namely the Estrogen receptor-alpha and the HER2 receptor. The breast and ovarian cancer susceptibility gene BRCA1 is an important genetic factor in hereditary breast and ovarian cancer and there is increasing evidence of an important role for BRCA1 in the sporadic forms of both cancer types. Our group and numerous others have shown in both preclinical and clinical studies that BRCA1 is an important determinant of chemotherapy responses in breast cancer. In this review we will outline the current understanding of the role of BRCA1 as a determinant of response to DNA damaging and microtubule damaging chemotherapy. We will then discuss how the known functions of this multifaceted protein may provide mechanistic explanations for its role in chemotherapy responses.

The activation function-1 domain of estrogen receptor α in uterine stromal cells is required for mouse but not human uterine epithelial response to estrogen

The activation function-1 (AF-1) domain of the estrogen receptor alpha (ERalpha) in stromal cells has been shown to be required for epithelial responses to estrogen in the mouse uterus. To investigate the role of the stroma in estrogenic responses of human uterine epithelium (hUtE), human/mouse chimeric uteri composed of human epithelium and mouse stroma were prepared as tissue recombinants (TR) that were grown in vivo under the renal capsule of female nude mouse hosts. In association with mouse uterine stroma (mUtS), hUtE formed normal glands surrounded by mouse endometrial stroma and the human epithelium influenced the differentiation of stroma into myometrium, such that a histologically normal appearing uterine tissue was formed. The hUtE showed a similar proliferative response and increase in progesterone receptors (PR) in response to 17beta-estradiol (E2) in association with either human or mUtS, as TRs. However, under identical endocrine and micro-environmental conditions, hUtE required 5-7 days exposure to E2 rather than 1 day, as shown for mouse uterine epithelium, to obtain a maximal proliferative response. Moreover, this extended length of E2 exposure inhibited mouse epithelial proliferation in the presence of mouse stroma. In addition, unlike the mouse epithelium, which does not proliferate or show regulation of PR expression in response to E2 in association with uterine stroma derived from mice that are null for the AF-1 domain of ERalpha, hUtE proliferates and PR are up-regulated in response to E2 in association genetically identical ERalpha knock-out mouse stromal cells. These results clearly demonstrate fundamental differences between mouse and human uterine epithelia with respect to the mechanisms that regulate estrogen-induced proliferation and expression of PR. Moreover, we show that genetically engineered mouse models could potentially aid in dissecting molecular pathways of stromal epithelial interactions in the human uterus.

Bcl-2, BAX, and apoptosis in endometrial hyperplasia after high dose gestagen therapy

OBJECTIVES

The aim of the study was to investigate apoptosis as a growth regulatory mechanism of gestagen in endometrial precancers and to compare differences in the apoptotic cascade after high and low dose gestagen regimens.

METHOD

Pre- and post-treatment paraffin-embedded endometrial hyperplasia specimens from women treated with levonorgestrel intrauterine device (n = 26) and women treated with 10 mg medroxyprogesterone for 10 days per cycle (n = 31) were examined for changes in the expression of Bcl-2 and BAX and the extent of apoptosis after 3 months of treatment. Immunohistochemical expression in tissue specimens for Bcl-2 and BAX was evaluated by H-score. Average number of apoptotic cells per hundred cells within ten different high power field (40 x) was evaluated for each section after in situ apoptosis detection (TUNEL method). A second group of patients with endometrial hyperplasia was examined after 1 week treatment with levonorgestrel IUD (n = 6) or medroxyprogesterone (n = 5) to determine early effects on expression of Bcl-2 and BAX and the extent of apoptosis.

RESULTS

All the patients in the IUD group (n = 31) but only about half of the patients in per oral group (16 of 26) responded to treatment. The glandular reduction in Bcl-2 expression was markedly greater for the IUD patients than for the patients who received oral gestagen. The decrease in BAX expression after IUD treatment was less than the reduction of Bcl-2. Decrease in glandular Bcl-2 after 3 months of treatment was coincident with a significant increase in the measurable amount of apoptosis. In stromal cells, the increase in expression of Bcl-2 and BAX was found after gestagen treatment, the response being much more marked for the IUD group. The non- responders to per oral gestagen had no Bcl-2 expression in stroma after 3 months of therapy whereas an increase was observed for the responders. After 1 week, glandular Bcl-2 expression was significantly reduced after treatment in the IUD group. As for the rest, no changes were detected in either of the groups.

CONCLUSION

Our results indicate that proteins in the apoptotic cascade are regulated by gestagen therapy in human endometrial precancers. Expression of these proteins is shown to be dependent on administration form and/or type of gestagen. Stromal Bcl-2 expression appears to be a potential biomarker which can separate responders of gestagen treatment from non-responders after oral administration.

The immune environment in human endometrium during the window of implantation

PROBLEM

Changes in the immune environment in the endometrium are believed to be important for successful implantation and maintenance of pregnancy. We have previously investigated global gene profiling in human endometrium during the window of implantation by oligonucleotide microarray technology, and analysis of these data underscore the regulation of a group of immune-related genes. The present study was therefore conducted to examine the pattern of expression and regulation of these genes including decay accelerating factor (DAF), indoleamine 2,3 dioxygenase (IDO), interleukin-15 (IL-15), IL-15 receptor alpha subunit (IL-15Ralpha), interferon regulatory factor-1 (IRF-1), lymphotactin (Lpn), natural killer-associated transcript 2 (NKAT2) and NKG5 in secretory and proliferative human endometrium.

METHOD OF STUDY

Endometrial biopsies were obtained from normally cycling women in the late proliferative and mid-secretory phase of the menstrual cycle. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and Northern blot analysis were used to determine the expression and regulation of these genes in secretory and proliferative human endometrium. Cellular localization of NKG5, Lpn and IDO by in situ hybridization in secretory-phase endometrium was also examined.

RESULTS

Semi-quantitative RT-PCR and Northern blot results demonstrate that there is a coordinated upregulation of this group of genes during the window of implantation.

CONCLUSIONS

We demonstrate the upregulation of immune-related genes IL-15Ralpha, Lpn and NKG5 in secretory versus proliferative human endometrium. We also demonstrate a similar upregulation in secretory endometrium of other immune-related genes, viz, DAF, IDO, IL-15, IRF-1 and NKAT2. The functions of these genes include stimulation of proliferation of uterine natural killer (uNK) cells, inhibition of cytolytic activity of uNK cells, inhibition of cell growth of T cells and other pathogens and inhibition of the classical complement pathway. Upregulation of these immune-related genes in the window of implantation suggests their role during the process of implantation and in immune tolerance of the implanting conceptus.

Human uterine natural killer cells: a reappraisal

The presence of granulated cells within the uterus of many species has been recognised for many years but only recently have these been recognised to be a type of NK cell. Various terms have been applied to the cells, including endometrial granulocyte, K cell and, in mouse and rat, granulated metrial gland cell. Although early studies are often based on histology and electron microscopy, these often include important information for current studies. In vitro studies of purified cells have focused particularly on cytotoxicity and cytokine production and roles in the control of trophoblast invasion and spiral artery remodelling in human pregnancy have been proposed. Evidence in mouse has implicated uNK cell production of IFN-gamma in vascular remodelling but evidence for such a role for human uNK cells remains to be established. Investigation of uNK cells in human pregnancy is hampered by the lack of availability of tissues from the first half of the second trimester of pregnancy when vascular remodelling occurs and also by possible differences between cells from different regions of decidua. The presence of similar cells in species with no trophoblast invasion into the uterus and epitheliochorial placentation raises the question of whether control of trophoblast invasion by human uNK cells is important in vivo and raises the possibility of another function which is conserved between species.

Fas, FasL, Bcl-2, and Bax in the endometrium of rhesus monkey during the menstrual cycle

To study possible role and regulation of apoptosis occurred in primate endometrium, the expression of apoptosis-related molecules, Fas, FasL, B cell lymphoma/leukaemia-2 (Bcl-2), and Bax were analyzed in relation to occurrence of apoptosis and proliferation in the cycling endometrium of the rhesus monkey using immunohistochemistry and Western blot. The cell apoptosis and proliferation were evaluated by means of in situ 3'-end labeling and Ki67 immunostaining, respectively. The results showed that the expressions of Fas, Fas ligand (FasL), Bcl-2, and Bax were co-localized predominantly in the epithelial cells of the endometrium. Modest Fas staining with no obvious change was detected throughout the menstrual cycle, while the levels of FasL and Bax protein in the epithelial cells increased in the secretory phase when apoptosis was most prevalent. In contrast, epithelial immunostaining for Bcl-2 was maximal during the proliferative phase and decreased in the secretory phase. Bcl-2 immunoreactivity was also detected in some immunocytes. The coordinated expression of Fas, FasL, Bcl-2, and Bax in the cycling endometrium of the rhesus monkey suggests that the cyclic changes in endometrial growth and regression may be regulated by the balance of these factors under the action of ovary steroids.

Does granulosa cell apoptosis have a role in the etiology of unexplained infertility?

OBJECTIVE(S)

To compare granulosa cell apoptosis in patients with unexplained infertility and tubal factor. Accelerated granulosa cell apoptosis may be the cause of unexplained infertility.

STUDY DESIGN

Setting was IVF-ET Unit of Cerrahpasa Medical Faculty, Istanbul University. GnRH analogs and gonadotropins were used for ovulation induction in patients with unexplained infertility (n=15) and tubal factor (n=15) undergoing in vitro fertilization and embryo transfer (IVF-ET) procedures. Following HCG injection and follicular aspiration, apoptosis of granulosa cells was assessed using the in situ DNA nick end labelling method and apoptosis rate was further determined by flow cytometry. Apoptosis rates were compared between two groups. Mann-Whitney's U-test and Student's t-test were used for statistics.

RESULTS

Apoptosis rate was significantly higher in the unexplained infertility group (33.20 +/- 35.62% versus 10.10 +/- 17.23%).

CONCLUSION(S)

Granulosa cell apoptosis seems to have a role in the etiology of unexplained infertility.

Lifetime expression of stem cell markers in the uterine endometrium

OBJECTIVE

To identify stem cells in uteri from the fetal to the postmenopausal period.

DESIGN

Descriptive, controlled study.

SETTING

Tertiary academic medical center.

PATIENT(S)

Forty archived uterine endometrial samples.

INTERVENTION(S)

Immunohistochemistry with c-kit/CD117, CD34, bcl-2, and Ki67.

MAIN OUTCOME MEASURE(S)

Immunostaining.

RESULT(S)

C-kit/CD117, CD34, bcl-2, and Ki67 were consistently expressed in the stroma of the basalis layer. Bcl-2 was restricted to the fetal uterine endometrium.

CONCLUSION(S)

By studying the immunolocalization of stem cell markers (i.e., c-kit, CD34, and bcl-2), we found that stem cells are present continuously in the uterine endometrium from the fetal period. The cells seem to be located mainly in the stroma of the basalis and to be independent of hormonal regulation to avoid cyclic shedding. A small number of latent stem cells dormant in the stroma of the basalis were found to have the potential for mesenchymal differentiation.

Involvement of granule-mediated apoptosis in the cyclic changes of the normal human endometrium

Our objective is to investigate the involvement of granule-mediated apoptosis in the cyclic changes of the endometrium. We demonstrated the localization of CD56, perforin, granzyme B and caspase-3 in the endometrium by immunohistochemistry. We also confirmed the localization of perforin by immuno-electron microscopy, and demonstrated apoptosis in endometrial glandular cells by TdT-mediated dUTP-biotin nick end labeling (TUNEL) and electron microscopy. Uterine CD56-positive natural killer (NK) cells expressed perforin and granzyme B in its cytoplasm. Uterine NK cells increased significantly in the endometrial stroma during the secretory phase, and peaked during the late secretory phase. These cells started decreasing in number during the menstrual period. In endometrial glandular cells, caspase-3 and TUNEL-positive cells increased significantly from the late secretory phase, with apoptosis reaching a peak during the menstrual period. Using electron microscopy, we observed uterine NK cells with chromatin rich, segmented nuclei and intracytoplasmic granules in the stroma obtained from late secretory phase endometria. These cells extended projections to the lining of endometrial glandular cells and attached to form a cell-to-cell contact. In addition, nuclear chromatin was observed to have already cohered and small cytoplasmic organelles were beginning to disappear, suggesting that these endometrial glandular cells were undergoing apoptosis. Utilizing immuno-electron microscopy, intracytoplasmic granules in uterine NK cells were stained with anti-perforin antibody. The findings of this study suggest that granule-mediated apoptosis in endometrial glandular cells induced by NK cells expressing perforin and granzyme B may be associated with the onset of menstruation.

The effect of hormone replacement therapy on the number and the proliferation index of endometrial leukocytes

This study aimed to determine the changes in endometrial leukocyte subpopulations under sequential hormone replacement therapy (HRT) during the late progestogenic phase. The number of leukocytes was determined using immunohistochemistry utilizing monoclonal antibodies to CD45 (total leukocytes), CD56 (endometrial granulated lymphocytes), CD3 (T-cells), and CD68 (macrophages). Leukocyte proliferation was demonstrated using in-situ hybridization with a histone probe, and the proliferation index was determined using double labelling for Ki67 (Mib1). Compared to the corresponding phase of the physiological cycle, sequential HRT-treated endometrium exhibited a 95% increase in CD45(+) cells (P < 0.05), a 130% increase in CD56(+) cells (P < 0.05), and a 113% increase in CD3 cells. There was a non-statistically significant drop in the number of CD68(+) cells. The number of proliferating leukocytes increased in sequential HRT endometrium.

Menstruation: induction by matrix metalloproteinases and inflammatory cells

Menstruation occurs at the end of a normal reproductive cycle in the human female, following the fall in progesterone resulting from the demise of the corpus luteum. Current data support a central role for the matrix metalloproteinases in menstruation but their focal pattern of expression within peri-menstrual and menstrual endometrium suggests local rather than hormonal regulation. This review emphasizes the similarities between menstruation and an inflammatory process and examines the relationship between cells of hemopoietic lineage, particularly mast cells, eosinophils, neutrophils and macrophages, and the local production and activation of matrix metalloproteinases within the endometrium. It proposes a complex of critical regulatory circuits, initially activated by the withdrawal of progesterone, which provide interactions between the migratory cells that produce a myriad of important regulatory molecules and endometrial stromal and epithelial cells which produce both chemokines and matrix metalloproteinases. These mechanisms could account for the focal nature of the tissue degradation at menstruation.

Phenotypic analysis and proliferative responses of human endometrial granulated lymphocytes during the menstrual cycle

The in vivo function of the unusual population of CD56+ CD16- endometrial granulated lymphocytes (eGLs) in human endometrium is unknown; their increased numbers in the secretory phase of the menstrual cycle suggests that they may play a role in the immunobiology of nonpregnant endometrium. In the present study, the phenotype and proliferative responses of eGLs at various phases of the menstrual cycle were compared with those in early pregnancy. Endometrial GLs were highly purified (> 98% CD56+) using immunomagnetic separation, and the expression of cell surface antigens was examined in smears using a double immunohistochemical labeling technique. Proliferative responses to mitogens and interleukin 2 (IL-2) were assessed in hanging drops in 60-well Terasaki plates. There was low to no expression of CD3, CD8, CD16, HML-1, L-selectin, and CD25 (IL-2 receptor alpha) on CD56+ cells isolated from nonpregnant and pregnant endometrium. The expression of CD2, CD49a, and CD122 (IL-2 receptor beta, IL-2Rbeta), however, increased from the proliferative to the late secretory phase of the menstrual cycle. In contrast, CD11a, CD69, and CD49d expression was high and did not vary with menstrual cycle phase; CD49d levels were significantly reduced in early pregnancy. Unlike early-pregnancy eGLs, none of the CD56+ eGL cultures throughout the menstrual cycle displayed phytohaemagglutinin (PHA)-induced lymphoproliferation. In contrast, eGLs from nonpregnant endometrium in the presence of 5 or 100 U/ml IL-2 after 48- and 120-h incubation showed significant proliferative responses, as did eGL cultures from early pregnancy. A significantly reduced number of proliferative phase eGL cultures proliferated in response to IL-2 compared to secretory phase and early-pregnancy eGL cultures. The IL-2-induced proliferative responses of CD56+ eGLs were associated with increased IL-2Rbeta (CD122) expression. These findings demonstrate 1) differential eGL expression of CD2, CD49a, and CD122 during the menstrual cycle; 2) differential IL-2-induced eGL proliferative responses during the menstrual cycle; and 3) differences between eGLs from nonpregnant and pregnant endometrium in CD49d expression and their ability to respond to PHA.