A quantitative evaluation of alpha1, alpha4, alphaV and beta3 endometrial integrins of fertile and unexplained infertile women during the menstrual cycle. A flow cytometric appraisal.

The expression of integrin molecules alpha1beta1, alpha4beta1 and alphaVbeta3 within endometrial tissue has been proposed as a marker of uterine receptivity during the implantation window. The present investigation examines by flow cytometric analysis the concentrations of alpha1, alpha4, alphaV and beta3 integrin subunits in endometrial stromal (ESC) and epithelial cells (EEC) in two groups of women throughout the menstrual cycle: normal fertile women (n = 27) and women with unexplained infertility (n = 26). Integrin concentrations in endometrial cells were calculated in relative fluorescence units against a negative cellular control. The assessment of integrin subunits detected the protein in ESC and EEC from the late proliferative to the late secretory phase. In both groups of women, the alpha1 was the highest integrin expressed in ESC and EEC throughout the menstrual cycle. All women exhibited low concentrations of alpha4-EEC at the time of the implantation window. Infertile women expressed lower concentrations of the alpha4-ESC during the proliferative and early secretory phase while lower concentrations of the alpha1-ESC were seen during the late secretory phase. Interestingly, the infertile women expressed lower concentrations of beta3-EEC in the early, mid-secretory and late secretory phases (P < 0.05). Infertile women also expressed lower concentrations of alpha1-EEC and alphaV-EEC during the late secretory phase (P < 0.05). It can be concluded that the quantitative determination of beta3-EEC by flow cytometry confirmed its potential feature as a marker of endometrial receptivity at the time of the implantation window. In addition, the defective expression of the alpha1-ESC found in the late secretory phase might be associated with the poor fertility outcome of women with unexplained infertility.     

In vivo correlation between IL-1beta concentration in uterine fluid and integrin expression pattern in infertile women

PROBLEM: To evaluate the possible correlation between interleukin-1beta (IL-1beta) and integrin expression. METHOD OF STUDY: Endometrium and uterine fluid from 77 infertile women and 24 fertile, healthy control were studied with immunohistochemistry and enzyme-linked immunosorbent assay for the presence of IL-1beta and integrin alphaVbeta3 and alpha4beta1 expression. RESULTS: Highest expression of alphaVbeta3 was found in epithelium and glands in endometria from fertile women. There was no positive correlation between IL-1beta and integrin expression pattern. CONCLUSION: This study confirms the importance of alphaVbeta3 as molecular marker of receptive phase. Also supports the views that synchrony in development of endometrium is necessary for successful nidation. There was however, contrary to results of previous in vitro studies, no positive correlation between IL-1beta and endometrial integrin patter expression.     

Changes in Endometrial Natural Killer Cell Expression of CD94, CD158a and CD158b are Associated with Infertility

Problem  Cycle-dependent fluctuations in natural killer (NK) cell populations in endometrium and circulation may differ, contributing to unexplained infertility.
Method of study  NK cell phenotypes were determined by flow cytometry in endometrial biopsies and matched blood samples.
Results  While circulating and endometrial T cell populations remained constant throughout the menstrual cycle in fertile and infertile women, circulating NK cells in infertile women increased during the secretory phase. However, increased expression of CD94, CD158b (secretory phase), and CD158a (proliferative phase) by endometrial NK cells from infertile women was observed. These changes were not reflected in the circulation.
Conclusion  In infertile women, changes in circulating NK cell percentages are found exclusively during the secretory phase and not in endometrium; cycle-related changes in NK receptor expression are observed only in infertile endometrium. While having exciting implications for understanding NK cell function in fertility, our data emphasize the difficulty in attaching diagnostic or prognostic significance to NK cell analyses in individual patients.     

Hydrosalpinges adversely affect markers of endometrial receptivity

While in-vitro fertilization (IVF) was initially developed in women with tubal factor infertility, recent clinical studies have suggested that the presence of hydrosalpinges lowers implantation and pregnancy rates. We postulated that these hydrosalpinges cause impaired endometrial receptivity. A total of 103 women with hydrosalpinges were prospectively evaluated, and compared with 55 infertile and 44 fertile controls. All women had endometrial biopsies during the window of implantation, analysed by conventional histological criteria, and also stained for three integrin markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha vbeta3). Women with hydrosalpinges (cases) expressed significantly less of the alpha vbeta3 integrin compared with controls. There was no difference in expression of alpha1beta1 or alpha4beta1 among groups. A significantly greater number of cases had out of phase histology and missing alpha vbeta3 (type I defects) and absent integrin expression despite normal histological maturation (type II) defects, compared with controls. Of 20 women with impaired endometrial receptivity who were also biopsied after hydrosalpinx surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven percent of type I and 57% of type II defects were corrected postoperatively. Using markers of endometrial receptivity, this study demonstrates that inflammatory hydrosalpinges have an adverse effect on endometrial receptivity, which in some cases may be overcome by surgical treatment of the hydrosalpinx.      

Distribution of integrin cell adhesion molecules in endometrial cancer.

Integrins are ubiquitous cell adhesion molecules that are involved in maintaining normal tissue morphology and have been implicated in the behavior of certain malignancies. We examined the expression of nine integrin subunits in 38 endometrial adenocarcinomas using immunohistochemistry. The pattern of integrin expression in the cancers was compared with that seen in the endometrium of 20 normal cycling women and 7 postmenopausal women. Integrin expression was correlated with grade, stage, nodal status, depth of invasion, steroid receptor status, and histological pattern. In endometrial cancers there was an inverse relationship between the number of integrins expressed and histological grade (P = 0.011). Of the normally expressed, constitutive endometrial epithelial integrin subunits (alpha 2, alpha 3, alpha 6, and beta 4), the least frequently seen in the cancers was the alpha 3 subunit (44.7%) and the most frequently found was alpha 6 (81.6%). The alpha 5 beta 1 integrin, a fibronectin receptor normally found only on endometrial stromal cells, was seen in 17.8% of cases of these epithelial cancers. In addition, a significant association was found between the loss of the alpha 2 beta 1 integrin and the presence of lymph node metastases (P < 0.001). These data suggest that a decline in integrin expression occurs more frequently in poorly differentiated endometrial cancers and that the loss of specific integrins may be associated with metastatic nodal spread.     

Clomiphene citrate does not affect the secretion of alpha3, alphaV and beta1 integrin molecules during the implantation window in patients with unexplained infertility.

BACKGROUND: The expression of integrin molecules on the endometrium suggests that certain integrins may participate in the cascade of molecular events leading to successful implantation. A prospective, controlled study was carried out to investigate the effect of clomiphene citrate (CC) on secretions of beta1, alpha3 and alphaV integrin molecules in the endometrium of patients with unexplained infertility during the implantation window. METHODS: A total of 40 endometrial samples was evaluated in both spontaneous (n = 13) and ensuing clomiphene-treated cycles (100 mg on days 5-9) and also from fertile women serving as controls (n = 14) during postovulatory 7th or 8th day of menstrual cycle. A semiquantitative grading system (H-score) was used to compare the immunohistochemical staining intensities. Endometrial thickness and serum oestradiol and progesterone concentrations were also measured on the day of sampling. RESULTS: Staining of alpha(v) but not beta1 and alpha3 integrins was significantly less intense in infertile cases than fertile control cases (1.42 +/- 0.12 versus 2.21 +/- 0.13 respectively, P = 0.012) and this was not restored to normal concentrations with treatment. CONCLUSIONS: Our study indicated that cc treatment significantly decreased the endometrial thickness and increased oestradiol and progesterone concentrations. However, secretion of alpha(v), beta1 and alpha3 integrin molecules, which might play a role in implantation, was not affected.     

Expression of estrogen and progesterone receptors in the endometrium of fertile and infertile women

The aim of the research is investigation of the endometrial hormonal status during menstrual cycle infertile and infertile women. 68 endometrial biopsies from 18-45 years old women have been studied. Some changes of ER and PR expression during menstrual cycle both in fertile and infertile women has been founded. However the ER expression in endometrial stroma and PR in the glands in a proliferative stage of cycle of fertile women are higher than in a secretory stage. In infertile women the PR expression in endometrial glands is opposite.     

Mid-luteal serum inhibin-A concentration as a marker of endometrial differentiation.

BACKGROUND: Recent studies have indicated that the corpus luteum is a major source of circulating inhibin-A and serum concentrations of inhibin-A may reflect the human luteal function. The present prospective study was undertaken to determine the usefulness of mid-luteal serum concentrations of inhibin-A as markers of endometrial receptivity (as assessed by histological dating and alphavbeta3 integrin expression) and whether they are better predictors of endometrial function than serum progesterone. METHODS: Consecutive infertile women (experimental group, n = 50) with regular menstrual cycles, and fertile women who were requesting contraception and had regular menstrual patterns and normal secretory endometria (control group, n = 10) were included. In all women basal body temperature, luteal serum concentrations of oestradiol, progesterone, prolactin, and inhibin-A, and endometrial biopsies were used in the same cycle to assess luteal function. RESULTS: Out-of-phase mid-secretory endometria were detected in 17 of the 50 infertile women. Lack of alphavbeta3 integrin expression was detected in 27 of the 50 mid-luteal endometrial biopsies. Thus, hormonal concentrations were compared in the mid-luteal phase between the following eight groups of women: group 1 (n = 10), control fertile women; group 2 (n = 50), infertile women (all); subdivided into group 3 (n = 33), with in-phase biopsies; group 4 (n = 17), with out-of-phase endometria; group 5 (n = 23), expressing alphavbeta3 integrin in endometria; group 6 (n = 27), whose endometria did not express alphavbeta3 integrin; group 7 (n = 18), with both in-phase endometrial biopsy and alphavbeta3 integrin expression; and finally group 8 (n = 12), whose endometria were out-of-phase and did not express alphavbeta3 integrin. Mid-luteal serum concentrations of oestradiol, progesterone, prolactin, and inhibin-A of the seven infertile groups were similar to those of the control group of fertile women. No statistically significant difference between the infertile groups was observed for any hormonal parameter considered. CONCLUSION: Mid-luteal serum inhibin-A determination does not accurately reflect endometrial function/maturation and it is not a better indicator of endometrial luteal phase dysfunction than mid-luteal serum progesterone.     

Removal of hydrosalpinges increases endometrial leukaemia inhibitory factor (LIF) expression at the time of the implantation window

BACKGROUND: The presence of hydrosalpinges is associated with lower implantation and pregnancy rates in women undergoing IVF-embryo transfer, while salpingectomy improves these parameters. Although the mechanism by which hydrosalpinges affects fertility is not entirely understood, an adverse effect on endometrial receptivity has been postulated. In this study, we hypothesized that the adverse effects of hydrosalpinges on fertility may be in part mediated by inappropriate endometrial expression of leukaemia inhibitory factor (LIF), a cytokine implicated in implantation. METHODS: In order to test our hypothesis, we prospectively examined the expression of LIF during the window of implantation in the endometrium of infertile women (n = 10) with hydrosalpinges prior to and following salpingectomy and of fertile controls (n = 10) by Western blotting and immunohistochemistry. RESULTS: LIF expression was significantly lower in infertile women with hydrosalpinges compared with fertile controls (P < 0.05). Salpingectomy resulted in an increase in LIF expression in eight out of 10 women with hydrosalpinges. LIF levels were increased by 231 +/-49% (mean +/- SEM) following salpingectomy. Immunohistochemical analysis confirmed the Western blot findings. The increased LIF immunoreactivity was predominantly localized to luminal and glandular epithelial cells. CONCLUSIONS: Our findings suggest that observed benefit from salpingectomy in infertile women with hydrosalpinges may be in part mediated by the up-regulation of endometrial LIF expression.     

Distribution of the alpha 1-alpha 6 integrin subunits in human developing and term placenta

The distribution of the alpha 1-alpha 6 as well as alpha v, beta 1, beta 3 and beta 4 integrin subunits in human first and second trimester and term placentas was studied by indirect immunofluorescence microscopy using a panel of monoclonal antibodies (mAbs). In first and second trimester villi, the alpha 1 and beta 1 integrin subunits were detected in the stromal cells, that were mostly also immunoreactive for desmin. Desmin-positive stromal cells were also found in villi of term placentas, but the stroma was negative for anti-alpha 1 and -beta 1. In the villous trophoblast, anti-alpha 6 and -beta 4 revealed a distinct basal immunoreactivity during all stages of development, whereas immunoreactivity for the alpha 3 and beta 1 subunits emerged during the second and third trimesters. Throughout placental development, endothelia of villous capillaries reacted prominently with anti-alpha 1 and -beta 1. Intermediate trophoblastic cells displayed a somewhat heterogenous immunoreactivity for the beta 1, alpha 1, alpha 3 and alpha 5 integrin subunits, and differed from villous trophoblast also in their lack of expression of the alpha 6 and beta 4 subunits. While nondecidualized endometrial cells displayed weak reactivity for the alpha 1 and beta 1 integrin subunits, the individual decidual cells presented both a basement membrane and a cell surface-confined immunoreactivity for anti-alpha 1, -alpha 3, and -beta 1. The results suggest a role for integrins in placental development, and show that expression of integrins is modulated during the differentiation of trophoblast, villous stroma, and decidual cells. Furthermore, the basal localization of alpha 6 beta 4 and alpha 3 beta 1 integrins suggests that they are employed as basement membrane receptors in the villous trophoblast, and the emergence of the alpha 3 beta 1 complex may reflect that the cytotrophoblast and syncytiotrophoblast recognize the basement membrane differently.     

Anti-CD9 monoclonal antibody-stimulated invasion of endometrial cancer cell lines in vitro: possible inhibitory effect of CD9 in endometrial cancer invasion

Cell surface marker CD9 has been reported to play a role in inhibiting trophoblastic cell invasion. Since the invasive properties of cancer cells may resemble those of trophoblasts, we decided to investigate the role of CD9 in the invasion of endometrial cancer cells. In normal human endometrium, CD9 was found to be constitutively expressed on epithelial cells, as reported previously. While epithelial cells of endometrial hyperplasia (n = 5) were also positive for the expression of CD9, endometrial adenocarcinomas (n = 15) showed reduced expression. In order to clarify the significance of this reduced CD9 expression in endometrial cancer, an in-vitro invasion assay system was used to assess the effect of anti-CD9 monoclonal antibody (mAb) on the invasive properties of endometrial cancer cell line. Anti-CD9 mAb significantly enhanced invasion of the RL95-2 and Ishikawa cell lines, without affecting cell proliferation. Since CD9 is associated with the integrin subunits beta(1), alpha(3) and alpha(6) in human endometrium, we investigated the functional relationship between CD9 and these integrins in the RL95-2 cell line. Monoclonal antibodies against the integrins beta(1), alpha(3) and alpha(6) inhibited RL95-2 cell invasion. However, anti-CD9 mAb continued to show a stimulatory effect on RL95-2 cell invasion after treatment with anti-integrin alpha(3) mAb. In contrast, the anti-CD9 mAb had no effect after treatment with the mAb for integrins alpha(6) and beta(1). These findings indicate that CD9 is involved in regulating the invasive properties of endometrial carcinoma cells and that this effect is partially mediated by integrin subunits alpha(6) and beta(1). Thus, CD9 appears to be involved in the prevention of endometrial cancer invasion.     

Effect of two thymosin fraction 5 polypeptides on human peripheral blood lymphocytes

Thymosin fraction 5 polypeptides beta 4 and alpha 1 were tested for their ability to affect certain immunological parameters of human peripheral blood lymphocytes (PBL). PBL were cultured with various concentrations of the peptides for 24 hours. Thymosin beta 4 was found to induce a significant decrease in the expression of the Fc alpha receptors of PBL, as well as in their ability to express antibody dependent cellular cytotoxic (ADCC) activity. In addition, this peptide had the ability to increase the percentage of T4 lymphocytes in normal and immunosuppressed donors and to decrease the percentage of T8 positive cells in normal donors. Finally, beta 4 peptide caused a small increase in the capacity of peripheral blood lymphocytes to form sheep red blood cell (SRBC) rosettes (ER). In parallel experiments thymosin alpha 1 was found inactive. The results presented here indicate that thymosin beta 4 may be used as an immunoregulatory molecule in patients with immunodeficiencies.     

Endometrial integrin expression in women undergoing IVF and ICSI: a comparison of the two groups and fertile controls

BACKGROUND: Integrins are thought to play a vital role in implantation. Three integrins in particular (alpha(4)beta(1), alpha(v)beta(3) and alpha(1)beta(1)) are all present during the implantation window. Defects in their expression have been linked to tubal disease, unexplained infertility and endometriosis. Hence, a reduced endometrial integrin expression would be expected in women attending for IVF due to these causes of infertility when compared with those with male factor infertility attending for ICSI. METHODS: Women attending for IVF (n = 25) and ICSI (n = 25) treatment were recruited, and timed endometrial biopsies were taken during the 'implantation window' (cycle day 20-24). A group of fertile women (n = 15) attending for sterilization was used as controls. RESULTS: There was no significant difference in integrin expression between patients undergoing IVF or ICSI. Neither did these groups differ from the control group. CONCLUSIONS: The endometrium in patients undergoing ICSI treatment is sometimes thought to be more receptive, as the infertility might be due to a male factor. This study shows that there is no significant difference in integrin expression between patients attending for IVF or ICSI and the control group. These data add to the increasing uncertainty about the clinical value of assessing the endometrium with only one marker, in this case integrins.     

Definition of unique traits of human CD4-CD8- alpha beta T cells.

We have studied the nature of human CD4-CD8- (double negative) alpha beta T cells to determine whether they possess unique characteristics which could further differentiate them from conventional CD4+ or CD8+ (single positive) T cells. We observed that double negative TCR alpha beta+ T cells differ from single positive T cells in the following respects: (i) their T cell receptor (TCR) repertoire is different, as revealed by the analysis of 47 clones derived from three individuals and by analysis of peripheral blood lymphocytes (PBL) prior to in vitro manipulation; (ii) their in vivo CD3:TCR expression is lower before in vitro manipulation and expansion; (iii) their direct proliferative response to IL-3, which is not mediated by secondary release of other T cell growth factors. These characteristics have also been recently ascribed to murine double negative alpha beta T cells, which develop extrathymically and are considered to be a distinct T cell lineage. Our data suggest that, like their murine counterparts, human double negative alpha beta T cells may represent a distinct T cell lineage which might develop extrathymically.     

The effect of antiprogestin on integrin expression in human endometrium: an immunohistochemical study

Integrins are cell surface receptors for the extracellular matrix and connect extracellular cell adhesion proteins to cytoskeletal components. Several investigators have recently described the expression of different integrins in the human endometrium as markers of receptivity. In the present study we investigated the effect of various doses of the antiprogestin mifepristone on the endometrial expression of integrins during the implantation phase. Endometrial biopsies from healthy fertile women were obtained in the midluteal phase. The study included one control and one, two or three treatment cycles. In treatment cycles either 2.5 (n = 9) or 5 mg (n = 5) of mifepristone was administered once weekly, 0.5 mg daily (n = 5), or 200 mg as a single dose administered on day 2 after the luteinizing hormone surge (day LH + 2; n = 8). By using polyclonal antibodies against integrin alpha(v)beta3, subunit beta3 and subunit alpha4 we found reduced immunostaining for alpha4 and beta3 subunit in glandular epithelium after treatment with mifepristone while alpha(v)beta3, expression appeared to be unaffected. No differences between treatment groups were noted. This study demonstrates that treatment with mifepristone interferes with integrin distribution during the implantation window. This may imply that the contraceptive effect of mifepristone is primarily due to impaired endometrial receptivity. However, since no effect was shown on the distribution of the vitronectin receptor, this integrin might be regulated differently by other factors such as cytokines.      

Immunological factors in endometriosis-associated reproductive failure: studies in fertile and infertile women with and without endometriosis

Immunopathophysiological mechanisms in endometriosis-associated reproductive failure were studied in appropriate populations: infertile and fertile women with and without endometriosis. The incidence of sera positive for any of the autoantibodies tested among infertile women with endometriosis (n = 25) was similar to that observed in the three control groups [unexplained infertility patients (n = 25) and fertile women with (n = 10) and without (n = 25) endometriosis]. The mean volume of peritoneal fluid was significantly elevated in women with endometriosis (both fertile and infertile) as compared with patients without endometriosis (fertile or infertile). The concentration of peritoneal fluid leukocytes and the percentage of cells positive for macrophage markers were significantly increased and the percentage of T lymphocytes significantly decreased in infertile women with endometriosis but not in patients with unexplained infertility and fertile women with endometriosis, as compared with fertile controls without endometriosis. Macrophages from infertile patients with endometriosis had higher sperm phagocytosis than did those from infertile women without endometriosis or fertile subjects with or without endometriosis. Incidences of serum and peritoneal fluid samples embryotoxic to the in-vitro development of 2-cell mouse embryos were significantly higher in infertile patients with endometriosis than in unexplained infertility patients and fertile women with or without endometriosis. It is concluded that immunological mechanisms of endometriosis-associated infertility exist but that these peritoneal immunological factors in infertile women with endometriosis are related to their subfertility rather than to the presence of ectopic endometrial implants. This is supported by the lack of immunological abnormalities observed among fertile women with endometriosis. These immunological abnormalities are lacking in patients with unexplained infertility.      

Differential expression of the interleukin 2 receptor beta (p75) chain on human peripheral blood natural killer subsets.

The interleukin-2 receptor (IL-2R) is composed of at least two subunits, the IL-2R alpha (P55, CD25/Tac) and IL-2R beta (p70-75) chains. In the present study we have identified the quantitative expression of IL-2R beta on subsets of NK cells in peripheral blood using flow cytometry and a recently established mAb against IL-2R beta (TU27). We demonstrate that NK cells are not a homogeneous population but that phenotypic subsets exist, and that the levels of IL-2R beta expression correlate with these subsets. The levels of IL-2R beta expression on NK subsets are CD3- CD16- CD56bright NK cells (immature NK) greater than CD16+CD4- NK cells (mature NK) greater than CD16+CD57+ NK cells (more mature NK) in adult peripheral blood lymphocytes. The level of IL-2R beta expression on CD16+ NK cells in cord blood is significantly higher than that in adult PBL. These findings suggest that there may be a inverse relationship between IL-2R beta expression and the differentiation of NK cells. IL-2R beta, preferentially expressed on the NK cells, may play an important role in differentiation and maturation of NK cells.