Concentration of plasminogen activators and inhibitor in the human endometrium at different phases of the menstrual cycle.

The concentrations of tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA) and plasminogen activator inhibitor (PAI-1) have been determined in endometrial curettings obtained from 46 subfertile women during proliferative, early or late secretory phases of the menstrual cycle. t-PA activity and antigen concentrations was significantly higher (P < 0.001) in late secretory endometrium than in proliferative or early secretory endometrium. Higher concentrations of PAI-1 antigen (P < 0.05) were also noted in late secretory phase than in proliferative and early secretory endometrium. However, u-PA concentration was not significantly different and no PAI activity could be demonstrated in the menstrual phases studied. Zymography studies confirmed the presence of both t-PA and u-PA in the endometrium. Ovarian hormonal patterns may therefore influence the activity of plasminogen activators especially of t-PA in the endometrium during various phases of the menstrual cycle.     

Endometrial tissue and plasma concentrations of 5-androstene-3 beta, 17 beta-diol during the menstrual cycle in normal premenopausal and perimenopausal women

A radioimmunoassay for 5-androstene-3 beta, 17 beta-diol (ADIOL) in human endometrium and plasma is described. The recognised criteria of reliability have been fulfilled. Plasma and endometrial tissue concentrations of ADIOL were determined in samples obtained from normal premenopausal and perimenopausal women (average ages 37 and 48 years respectively) at different phases of the menstrual cycle. In perimenopausal women plasma concentrations of ADIOL did not vary throughout the cycle (proliferative phase: 411 +/- 95 (SEM) pg/ml; secretory phase: 462 +/- 28.5 (SEM) pg/ml). For the premenopausal group the pattern was similar (proliferative phase: 568.4 +/- 56.9 (SEM) pg/ml; secretory phase: 663.1 +/- 64.7 (SEM) pg/ml) although a significant difference (P less than 0.05) was noted between late proliferative and late secretory phase levels in these women. A different pattern was observed for endometrial tissue concentrations of ADIOL. In both groups of women a significant (3-4-fold) increase occurred during the secretory phase. There was no apparent relationship between plasma and tissue concentrations of ADIOL either during the proliferative or the secretory phase. There was, however, an age associated decrease for both tissue and plasma ADIOL. Theories are proposed to account for the increase in ADIOL concentration during the luteal phase.     

17 beta-hydroxysteroid dehydrogenase activity in leiomyoma and myometrium and its relationship to concentrations of oestrone, oestradiol and progesterone throughout the menstrual cycle

The activity of the enzyme 17 beta-hydroxysteroid dehydrogenase (17 beta-OHSD) and concentrations of oestrone (E1), oestradiol (E2) and progesterone have been measured in leiomyoma and myometrium obtained at different stages of the menstrual cycle. Apart from conversion of E2 to E1 in the proliferative phase, no significant difference in enzyme activity was noted between normal and tumour tissue. However, interconversion in both tissues was shown to be higher in the secretory than the proliferative phase of the menstrual cycle. E1 concentrations were significantly higher (P less than 0.01) in leiomyoma than in myometrium, obtained during the proliferative phase. Concentrations of both oestrogens, in some tumour and normal tissues, were higher in the proliferative than the secretory phase. Secretory phase tissues contained higher concentrations of progesterone than those obtained in the proliferative phase of the menstrual cycle. Considerable differences in both enzyme activity and steroid concentrations were noted in different areas of the same tumour.     

Aquaporin-2 expression in human endometrium correlates with serum ovarian steroid hormones

The aim of the present study was to examine the expression of aquaporin-2 (AQP2), a member of the water channel family aquaporins (AQPs), in human uterine endometrium and its modulation of ovarian steroid hormone at the proliferative and secretory phases. Western blot, immunohistochemistry, and RT-PCR were employed in the present study. Western blot revealed a 29-kDa band that represented AQP2 in human endometrium. The expression of AQP2 in endometrium was confirmed by RT-PCR and immunohistochemical results. The immunohistochemical analysis demonstrated that AQP2 was prominent in luminal and glandular epithelial cells of endometrium. The levels of endometrial AQP2 expression changed during the menstrual cycle and were higher in the secretory endometrium than in the proliferative endometrium. A significantly high level of AQP2 was detected at the mid-secretory phase. There was a positive correlation between the levels of the endometrial AQP2 expression and the concentrations of the serum 17beta-estradiol (E2) or/and progesterone (P4). These data for the first time corroborate that AQP2 is expressed in human endometrium and that the expression of AQP2 in human endometrium might be regulated by E2 or/and P4. The changed expression of AQP2 at different phases of the menstrual cycle may be essential to reproductive physiology in human. The high level of endometrial AQP2 expression was observed at the mid-secretory phase, the time of embryo implantation, suggesting that AQP2 might play physiological roles in the uterine receptivity.     

The differences in RCAS1 and DFF45 endometrial expression between late proliferative, early secretory, and mid-secretory cycle phases

RCAS1 expression is related to the regulation of activated immune cells and to connective tissue remodeling within the endometrium. DFF45 seems to play an important role in the apoptotic process, most likely by acting through the regulation of DNA fragmentation. Its expression changes within the endometrium seem to be related to the resistance of endometrial cells to apoptosis. The aim of the present study was to evaluate RCAS1 and DFF45 endometrial expressions during ovulation and the implantation period. RCAS1 and DFF45 expression was assessed by the Western-blot method in endometrial tissue samples obtained from 20 patients. The tissue samples were classified according to the menstrual cycle phases in which they were collected, with a division into three phases: late proliferative, early secretory, and mid-secretory. The lowest level of RCAS1 and the highest level of DFF45 endometrial expression was found during the early secretory cycle phase. Statistically significantly higher RCAS1 and statistically significantly lower DFF45 endometrial expression was identified in the endometrium during the late proliferative as compared to the early secretory cycle phase. Moreover, statistically significantly higher RCAS1 and statistically significantly lower DFF45 expression was found in the endometrium during the mid-secretory as compared to the early secretory cycle phase. The preparation for implantation process in the endometrium is preceded by dynamic changes in endometrial ECM and results from the proper interaction between endometrial and immune cells. The course of this process is conditioned by the immunomodulating activity of endometrial cells and their resistance to immune-mediated apoptosis. These dynamic changes are closely related to RCAS1 and DFF45 expression alterations.     

Identification by hybridization histochemistry of human endometrial cells expressing mRNAs encoding a uterine beta-lactoglobulin homologue and insulin-like growth factor-binding protein-1.

A beta-lactoglobulin homologue (beta LG/PP14) and insulin-like growth factor-binding protein-1 (IGFBP-1) are two major secretory proteins of the human endometrium. In the present study, we have shown that beta LG/PP14 mRNA is expressed in the endometrium in a cyclic manner, being hardly detectable in midcycle and most abundant during the late secretory phase. IGFBP-1 mRNA is also expressed in endometrium, but in amounts smaller than those encoding beta LG/PP14 and with maximal accumulation earlier in the secretory phase. The expression of these two mRNAs occurs in different cell types of the endometrium, as revealed by in situ hybridization techniques using single-stranded RNA probes. The glandular epithelial cells accumulate beta LG/PP14 mRNA during the late secretory phase of the cycle, whereas only the stromal cells of the late secretory endometrium express IGFBP-1 mRNA. In contrast to the endometrium, the two mRNAs are present at very low abundance in the fallopian tubes where they are expressed in the epithelial cells of the mucosa.     

Morphometry and discriminant analysis of the endometrium.

The authors dated 100 normal endometrial biopsies. Only endometrial specimens with histologically confirmed subphases and no evidence of organic disease were accepted for study. The morphometry and stereologic measures of the glands, lumina and endometrial epithelium were assessed. Quantitative assessment of the normal endometrium supported the histologic events that occur in the endometrial cycle (proliferative and secretory phases). There was a progressive increase in morphometric and stereologic values of the glands, epithelium and lumina during the endometrial cycle. Using stepwise discriminant analysis, 94% of the specimens were correctly classified into the categories of proliferative and secretory phase; two quantitative parameters were required, the epithelial volume density and longest luminal diameter. When three subphases within proliferative and secretory endometrium were considered, the overall accuracy was 90% and 78%, respectively.     

Uptake of [3H]-arachidonic acid by human endometrium. Differences between normal and menorrhagic tissue

Human proliferative and secretory endometrium from normal women and from menorrhagic patients was maintained in culture for up to 24 h in the presence of [3H]-arachidonic acid (3H-AA). This prostaglandin (PG) precursor was incorporated into endometrial neutral lipids and phospholipids in a time-dependent manner. Uptake of 3H-AA into phospholipids was significantly higher in normal secretory endometrium than in normal proliferative endometrium. However, this increased uptake of 3H-AA into phospholipids between the 2 phases of the cycle did not occur in menorrhagic endometrium. In contrast, uptake of 3H-AA into neutral lipids (especially triglyceride) was approximately 2-fold higher in menorrhagic endometrium compared to normal endometrium at both stages of the cycle, particularly during the proliferative phase. Abnormalities apparently exist in menorrhagic endometrium in the uptake processes which control arachidonic acid (AA) turnover. These abnormalities may be responsible, in part for abnormal PG production by menorrhagic endometrium.     

Metabolism of adrenal androgens by human endometrium and adrenal cortex

The enzyme 17 beta-hydroxysteroid dehydrogenase (17OHSD) was studied in human endometrium and adrenal cortex with respect to the metabolism of 5-androstene-3 beta,17 beta-diol (androstenediol) and dehydroepiandrosterone (DHA). The aim was to provide further information concerning the origin and biological significance of these androgens in endometrium, particularly the increased concentrations of the secretory phase and to compare the characteristics of the enzyme in the two tissues. In both endometrium and adrenal cortex the metabolism of androstenediol to DHA was linear with time and increasing enzyme concentration. The preferred cofactor was NAD and the apparent Km values were 3.4 +/- 0.2 (SD) microM (n = 3) for endometrium and 30.5 +/- 6.1 microM (n = 3) for adrenal cortex. In endometrium DHA was not metabolised to androstenediol in the presence of either NADH or NADPH whereas in the adrenal cortex both cofactors were utilised. However, the concentration of NADH required to achieve maximum enzyme activity was 10-fold higher (1 mM) than for NADPH (0.1 mM) and maximum activity with NADH was only 30% of that using NADPH. The apparent Km was 125 microM DHA (n = 2). The study indicates that androstenediol in endometrium does not arise from DHA metabolism but that its presence could be due to a binding protein particularly during the secretory phase. Our findings also suggest that the enzyme of endometrium differs from that of the adrenal cortex and that the kinetic properties may be related to the physiological requirements of the two tissues.     

MUC16对子宫内膜容受性的影响及其意义

目的：多囊卵巢综合征（Polycystic Ovary Syndrome,PCOS）系由于体内复杂的内分泌和代谢环境影响了子宫内膜稳态,导致子宫内膜容受性下降,造成患者生育力减弱和不良妊娠结局。通过测定多囊卵巢综合征患者子宫内膜与正常生育力妇女增生期、分泌早、中、晚期子宫内膜中MUC16的相对表达量,本文探讨MUC16与PCOS患者子宫内膜容受性下降的关系,为临床上改善PCOS患者子宫内膜容受性,提高PCOS患者的妊娠率,降低流产率提供一条新的可能途径。方法：选择PCOS患者子宫内膜、正常生育力妇女增生期、分泌早、中、晚期子宫内膜各20例,用免疫组化SP法检测MUC16在各组的表达情况。结果：（1）MUC16在月经周期各期均有表达,在分泌中期表达最强。（2）PCOS组MUC16的表达较分泌中期组弱,差异有显著性（P〈0.05）。结论：（1）在子宫内膜中的表达呈周期性变化。（2）PCOS患者子宫内膜中MUC16表达异常可能使子宫内膜容受性下降,推测其与胚胎不能正常着床或着床后发育不良、导致流产有关。     

Immunoreactive beta-endorphin is demonstrable in the secretory but not in the proliferative endometrium

The presence of immunoreactive beta-endorphin (ir beta-E) in the endometrium was studied by immunoperoxidase staining of tissue sections at various stages of the menstrual cycle. Ir beta-E was found in the endometrium during the secretory phase of the cycle, from the fourth postovulatory day to the desquamating phase, but not in the proliferative phase or during the first three postovulatory days of the cycle. Ir beta-E was located in the cytoplasm of the epithelial cells of the glands. Samples of endometrium were homogenized, and peptides were extracted with Sep Pak C18 cartridge, followed by purification of ir beta-E by cation-exchange high-pressure liquid chromatography. In samples of secretory endometrium, a peak of ir beta-E was found with identical location of that of reference beta-E. The concentration of ir beta-E in the secretory endometrium varied from 5.0 to 12.6 pg/g of tissue. The appearance of ir beta-E in the endometrium during the secretory phase may have importance in the early events of reproduction.     

Uptake of [H]-arachidonic acid by human endometrium. Differences between normal and menorrhagic tissue

Human proliferative and secretory endometrium from normal women and from menorrhagic patients was maintained in culture for up to a 24 h in the presence of [³H]-arachidonic acid (³H-AA). This prostaglandin (PG) precursor was incorporated into endometrial neutral lipids and phospholipids in a time-dependent manner. Uptake of ³H-AA into phospholipids was significantly higher in normal secretory endometrium than in normal proliferative endometrium. However, this increased uptake of ³H-AA into phospholipids between the 2 phases of the cycle did not occur in menorrhagic endometrium. In contrast, uptake of ³H-AA into neutral lipids (especially triglyceride) was approximately 2-fold higher in menorrhagic endometrium compared to normal endometrium at both stages of the cycle, particularly during the proliferative phase. Abnormalities apparently exist in menorrhagic endometrium in the uptake processes which control arachidonic acid (AA) turnover. These abnormalities may be responsible, in part for abnormal PG production by menorrhagic endometrium.     

Uptake of [3H]-arachidonic acid by human endometrium. Differences between normal and menorrhagic tissue

Human proliferative and secretory endometrium from normal women and from menorrhagic patients was maintained in culture for up to a 24 h in the presence of [³H]-arachidonic acid (³H-AA). This prostaglandin (PG) precursor was incorporated into endometrial neutral lipids and phospholipids in a time-dependent manner. Uptake of ³H-AA into phospholipids was significantly higher in normal secretory endometrium than in normal proliferative endometrium. However, this increased uptake of ³H-AA into phospholipids between the 2 phases of the cycle did not occur in menorrhagic endometrium. In contrast, uptake of ³H-AA into neutral lipids (especially triglyceride) was approximately 2-fold higher in menorrhagic endometrium compared to normal endometrium at both stages of the cycle, particularly during the proliferative phase. Abnormalities apparently exist in menorrhagic endometrium in the uptake processes which control arachidonic acid (AA) turnover. These abnormalities may be responsible, in part for abnormal PG production by menorrhagic endometrium.     

Expression of the chemokine eotaxin and its receptor, CCR3, in human endometrium

Eosinophils are present in human endometrium only immediately before and during menstruation, suggesting a role in that process. The expression of the eosinophil chemoattractant, eotaxin, and its receptor, CCR3, within the human endometrium were investigated by immunohistochemical analysis of tissue sections spanning the entire menstrual cycle. Eotaxin was localized to perivascular cells in the late secretory phase, and it was also identified in eosinophils. However, the highest levels of this chemokine were present in both luminal and glandular epithelial cells during the proliferative and secretory phases of the cycle. Treatment of endometrial tissue with monensin, which blocks protein secretion, increased epithelial immunoreactive eotaxin, substantiating synthesis in these cells. Although the CCR3 receptor was expressed by eosinophils, it was also strongly expressed by endometrial epithelial cells. The CCR3 receptor on purified, cultured endometrial epithelial cells was functional, as assessed by a transient Ca(2+) flux in response to eotaxin. These analyses demonstrate that eotaxin is expressed by endometrial cells and may therefore be involved in the recruitment of eosinophils into this tissue premenstrually. However, the observation that this chemokine and the CCR3 molecule are strongly expressed by epithelial cells throughout the cycle suggests that these proteins may have additional important functions within the endometrium.     

The effect of estradiol-17 beta and actinomycin D on the release of PGF and PGE from separated cells of human endometrium

Estradiol-17 beta selectively stimulated the release of PGF from separated glandular but not stromal cells of human secretory endometrium (p less than 0.025) but had no effect on PGF release from either type of cells obtained from proliferative endometrium. PGE release was not affected by estradiol-17 beta. Actinomycin D did not antagonise the effect of estradiol-17 beta on PGF release from secretory, glandular cells. Basal release of PGF from these cells was stimulated by actinomycin D alone (100 ng/ml) (p less than 0.025) and PGE release stimulated in the presence of estradiol-17 beta. Actinomycin D had no effect on PGF or PGE release from proliferative endometrium. These findings suggest that estradiol-17 beta stimulates PGF release by a mechanism that does not affect PGE release and which is not dependent on the synthesis of new protein. The basal release of PGF and PGE by glandular cells of secretory endometrium in vitro is regulated by protein/proteins which reduce PG release.     

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.     

Menstrual cycle-associated alteration of sulfogalactosylceramide in human uterine endometrium: possible induction of glycolipid sulfation by sex steroid hormones

The human uterine endometrium is a tissue in which cell proliferation and differentiation are strictly controlled by sex steroid hormones, and these hormone-controlled cellular events occurring in association with the menstrual cycle of the uterine endometrium should be accompanied by characteristic molecular and metabolic changes. To characterize the menstrual cycle at the molecular level, we analyzed the glycolipids of human uterine endometrium in the proliferative and secretory phases of the menstrual cycle. Neutral glycosphingolipids from uterine endometrium comprised globo-series glycosphingolipids, such as GlcCer, LacCer, Gb3Cer, and Gb4Cer, and the relative concentrations remained constant in the two phases. However, in the case of acidic glycosphingolipids, although the concentrations of sialoglycosphingolipids remained at constant levels in the two phases, sulfatide, I3-SulfoGalCer, dramatically increased from the proliferative to the secretory phase, amounting to 7-17 nmol/g dry weight in the proliferative phase and 115-245 nmol/g dry weight in the secretory phase. Since sulfatide was the only glycolipid that changed in association with the menstrual cycle, it is likely that the sulfotransferase responsible for the synthesis of sulfatide might be induced by sex steroid hormones, estrogen and progesterone, and that sulfatide might play an essential biological role in the secretory phase of the menstrual cycle in the uterine endometrium.     

Characterization of intraepithelial lymphocytes in human endometrium

Intraepithelial lymphocytes (IELs) were characterized and quantitated in normal non-pregnant endometrium and in early pregnancy decidua using H & E and phloxine tartrazine stains and a panel of monoclonal antibodies in an indirect immunoperoxidase technique. The relative numbers of granulated and non-granulated IELs varied according to menstrual cycle stage and in early pregnancy all IELs appeared to be granulated. There was a higher surface:gland ratio for IELs in proliferative endometrium compared with late secretory phase and early pregnancy endometrium. In proliferative endometrium most IELs were T cells, predominantly of the CD8 + subset. In first trimester decidua, higher numbers of CD56 + cells were observed, in keeping with the increased proportion of granulated IELs. IEL populations in human endometrium vary according to menstrual cycle stage and endometrial IELs appear to show phenotypic differences compared with IELs in the human gastrointestinal tract.     

Spatial and temporal characterization of endometrial mesenchymal stem-like cells activity during the menstrual cycle

The human endometrium is a highly dynamic tissue with the ability to cyclically regenerate during the reproductive life. Endometrial mesenchymal stem-like cells (eMSCs) located throughout the endometrium have shown to functionally contribute to endometrial regeneration. In this study we examine whether the menstrual cycle stage and the location in the endometrial bilayer (superficial and deep portions of the endometrium) has an effect on stem cell activities of eMSCs (CD140b⁺CD146⁺ cells). Here we show the percentage and clonogenic ability of eMSCs were constant in the various stages of the menstrual cycle (menstrual, proliferative and secretory). However, eMSCs from the menstrual endometrium underwent significantly more rounds of self-renewal and enabled a greater total cell output than those from the secretory phase. Significantly more eMSCs were detected in the deeper portion of the endometrium compared to the superficial layer but their clonogenic and self-renewal activities remained similar. Our findings suggest that eMSCs are activated in the menstrual phase for the cyclical regeneration of the endometrium.