Endothelial cell proliferation in the endometrium of women with menorrhagia and in women following endometrial ablation

Local endometrial aberrations are thought to be the major contributing factor to essential menorrhagia. Here we have examined the role of endometrial angiogenesis, the growth of new blood vessels, in essential menorrhagia. Our study tested two hypotheses: firstly that angiogenesis is disturbed in the endometrium of women with menorrhagia; and secondly that when menstrual blood loss is decreased following endometrial ablation, an endometrial environment favouring normal angiogenesis has returned. Angiogenesis was measured by endothelial cell proliferation. Proliferating endothelial cells were identified by an immunohistochemical double staining technique. A total of 57 women participated in this study, of whom 19 were controls, 20 had menorrhagia and 18 were 3-6 months post-ablation. There was a significant increase in endothelial cell proliferation in the endometrium of patients with menorrhagia compared with the control endometrium. Conversely, post-ablation endometrium showed a non-significant decrease in endothelial cell proliferation. The increased endothelial cell proliferation in the endometrium of patients with menorrhagia was not the result of a general increase in endometrial cellular proliferation and did not result in a change in endothelial cell concentration compared with control endometrium. These results support the hypothesis that angiogenesis is disturbed in the endometrium of patients with menorrhagia and normalized in post-ablation endometrium.

Immunohistochemical detection of cathepsin D in endometrium from long-term subdermal levonorgestrel users and during the normal menstrual cycle

A previous report has shown that progesterone up-regulates cathepsin D expression in human endometrial cell culture. In women using the levonorgestrel-releasing Implant Norplant, the plasma levonorgestrel and immunoreactive endometrial progesterone receptor concentrations are elevated. However, the functional status of these receptors is not known. This study used endometrial cathepsin D expression both as an indirect marker for the functional status of endometrial progesterone receptors, and to identify the cell types that express cathepsin D. The results show that cathepsin D is primarily found in glandular epithelia and luminal epithelia in control and Norplant endometria. There is no significant difference in cathepsin D expression between the control and Norplant endometria, between the various stages of the menstrual cycle, or between Norplant users with varying degrees of breakthrough bleeding. Cathepsin D is also detected in cells scattered in the stroma in both control and Norplant endometria. The majority of these cells are macrophages. These data indicate that there is no evidence for progesterone regulation of cathepsin D in the human endometrium. Cathepsin D thus cannot be used as a marker for the functional status of progesterone receptors found in the Norplant-exposed endometrium.

Continuing transmission of sexually transmitted diseases among patients infected with HIV-1 attending genitourinary medicine clinics in England and Wales

OBJECTIVE

To determine whether those who are aware of being infected with HIV continue to adopt behaviours that place others at risk of HIV infection.

DESIGN

Ongoing survey of current diagnosis of sexually transmitted disease and awareness of HIV infection among patients attending genitourinary medicine clinics.

SETTING

Six genitourinary medicine clinics in England and Wales (two in London and four outside) participating in unlinked anonymous HIV serosurveillance during 1990-3.

SUBJECTS

All attenders having blood drawn for syphilis serology for the first time during the calendar quarter of attendance.

MAIN OUTCOME MEASURES

The proportion of syphilis serology specimens with antibody to HIV-1 detected by unlinked anonymous testing of the residue. The proportion of attenders infected with HIV-1 who remained clinically undetected, and the proportion who had another recently acquired sexually transmitted disease.

RESULTS

Of 85441 specimens tested, 2328 (2.7%) were positive for antibodies to HIV-1. About 30% of these specimens were from attenders whose HIV-1 infection remained clinically undetected. HIV-1 infection was found to coexist with another recently acquired sexually transmitted disease in 651 attenders, of whom 522 were homosexual or bisexual men. Of these, 245 (47%) already knew themselves to be infected with HIV-1. This proportion increased between 1990 and 1993.

CONCLUSIONS

A considerable proportion of patients infected with HIV-1 are not identified by voluntary confidential HIV testing in genitourinary medicine clinics. Substantial numbers of homosexual or bisexual men attending genitourinary medicine clinics continue to practise unsafe sex despite being aware of their infection with HIV-1.

Uterine glandular area during the menstrual cycle and the effects of different in-vitro fertilization related hormonal treatments

The human uterine glandular epithelium undergoes a sequence of well characterized changes during the menstrual cycle that presumably play an important role in preparation for blastocyst implantation. The aim of this study was to measure objectively glandular volume over the entire menstrual cycle and compare the results with eight different clinical superovulation or hormone replacement therapy (HRT) subject groups. Endometrial biopsies were taken from control normal menstrual cycle subjects (n = 96), and eight other smaller groups of women who had received different in-vitro fertilization (IVF) related treatments. The total area of glandular epithelium was objectively measured from routine histological slides using computerized image analysis. Control menstrual cycle results showed a significantly greater gland area in the early secretory stage of the cycle than at any time between the early proliferative through to the mid-late proliferative stages (P < 0.05). IVF patients receiving clomiphene citrate and human menopausal gonadotrophin had a significantly smaller glandular area than those in the control groups at equivalent stages of the menstrual cycle. The use of progesterone supplementation removed this significant difference. Patients on the ¿Flare' regime had the highest gland area, although this was not significantly different from controls. Buserelin down-regulation gave a gland area that was closest to the normal cycle controls. The three HRT groups showed high variability in gland volume between patients. The results from this study demonstrate that superovulation can cause significant alterations in endometrial gland volume, but that these do not necessarily preclude implantation.

Vascular smooth muscle alpha-actin distribution around endometrial arterioles during the menstrual cycle: increased expression during the perimenopause and lack of correlation with menorrhagia

Menorrhagia affects approximately 9% of all women, increasing to 20% during the perimenopause. The majority of menstrual loss occurs through the spiral arterioles - specialized endometrial vessels that are intimately involved in controlling menstruation. Our aim was to compare the distribution of vascular smooth muscle alpha-actin using immunohistochemical techniques in the endometrium of women before and during the perimenopause and with or without menorrhagia. We hypothesized that differences in vessel numbers and types exhibiting alpha-actin staining would exist between these groups, reflecting structural/functional differences. The results showed that perimenopausal menorrhagic women had significantly more smooth muscle alpha-actin expression than non-perimenopausal controls in four out of five menstrual cycle stages (P < 0.05), while perimenopausal non-menorrhagic women demonstrated a significant increase at the mid-proliferative stage only (P < 0.007). No significant differences occurred between women with or without menorrhagia before or during the perimenopause. Perimenopausal women had significantly more straight arterioles (P < 0.02) than women prior to perimenopause at the late secretory stage, while non-perimenopausal women demonstrated significantly higher numbers of spiral arterioles (P < 0.002) in the early secretory stage, although this difference had disappeared by the late secretory stage. In conclusion, we found no major differences in endometrial vascular smooth muscle alpha-actin staining between women with and without menorrhagia, but significant increases in alpha-actin staining in women showing perimenopausal symptoms.

Structure and function of endometrial blood vessels

The endometrial blood vessels form a vascular bed with a number of unusual properties. Unlike most adult vasculature these blood vessels undergo constant cycles of growth and regression during the reproductive life of the female. This short review covers a number of different aspects relating to endometrial vascular structure and function during endometrial growth, implantation, endometrial regression and menstruation. Video footage from in-vivo microscopy of the rat endometrial subepithelial capillary plexus on the morning of day 6 of pregnancy is included in the CD-ROM. This shows the dramatic changes that occur to the endometrial capillaries at the time of embryo implantation.

Blood vessel growth in the endometrium

Angiogenesis, or formation of new blood vessels by sprout formation from existing vessels, is generally considered to be the only mechanism by which blood vessel growth occurs. This traditional concept of angiogenesis has been derived largely from observations of experimental systems. Relatively fewer studies on angiogenesis have been carried out using normal angiogenic situations where vessel growth occurs in a controlled three-dimensional fashion throughout the tissue. Recent advances in the treatment of infertility and outpatient gynecological procedures have led to greater accessibility to normal human endometrium, thus providing new opportunities to study the process of angiogenesis in a physiological context. However, to date, it appears that very little work had been done in relation to endometrial angiogenesis apart from the location of numerous angiogenic and other growth factors with potential to influence angiogenesis in the endometrium, and here there have been few attempts to link these observations with actual angiogenic events. The purpose of this review is to summarize the literature regarding angiogenesis in the endometrium, including work from our own laboratory, and to suggest that blood vessel growth in the endometrium may occur by a mechanism that differs from classical angiogenesis.

Effect of feeding a mineral-vitamin supplement before calving on the calving performance of a trace element deficient dairy herd

A split-herd, randomised mineral-vitamin supplementation experiment was carried out in a large, trace element deficient dairy herd over two years. Ten weeks before the herd's mean calving date, 147 Holstein-Friesian cows were fed grass silage on to which 50 g per head of a mineral-vitamin supplement (3000 mg copper, 500 mg iodine, 45 mg selenium and 80 mg cobalt per kg of supplement as specified) was sprinkled twice daily and 147 cows were fed the silage alone until calving. The supplement had no effect on the incidence of abortion (1.4 per cent), dystocia (2.3 per cent), fetal maldisposition (7.3 per cent), perinatal mortality (6.0 per cent) or retained fetal membranes (4.0 per cent), but it significantly increased the concentrations of trace elements in the blood and tissues of dead perinatal calves from 10 supplemented dams compared with those from eight unsupplemented dams. It also significantly increased the concentrations of trace elements in the blood of the cows and newborn calves in the supplemented group.

Blood vessel growth and endothelial cell density in rat endometrium

The aim of the present study was to quantify endothelial cell density in rat endometrium during early pregnancy (a time of increased endothelial cell proliferation), using immunohistochemical methods. Despite the occurrence of vessel growth, the endometrial endothelial cell density remained unchanged before embryo implantation, indicating that endothelial cell proliferation keeps pace with proliferation of the surrounding endometrial cells. After implantation, endothelial cell density falls at embryo sites on day 6, despite very high endothelial cell proliferation rates. This is probably due to the oedema caused by the localized increase in vascular permeability at implantation sites. We hypothesize that this reduction may provide a stimulus for the observed endothelial cell proliferation, rather than a direct angiogenic stimulus from the embryo.

Immunolocalization of endothelin and neutral endopeptidase in the endometrium of users of subdermally implanted levonorgestrel (Norplant)

Subdermally implanted slow-release levonorgestrel (Norplant), a widely used effective contraceptive, has a high rate of discontinuation due to unacceptable menstrual bleeding disturbances. Endothelin (ET), a potent vasoconstrictor, varies across the menstrual cycle in normal endometrium. It has been proposed that ET has a potential paracrine role in the regulation of uterine blood flow. Neutral endopeptidase (NEP), a membrane-bound ecto-enzyme, can inactivate ET and is localized principally in endometrial stroma. We have compared the immuno-localization of ET and NEP in endometrial biopsies from Indonesian women using Norplant with normal controls. Differences were observed in the glandular and luminal epithelium of Norplant-treated subjects, where ET immunostaining was low while NEP immunoreactivity was increased. The latter may represent a local increase in enzyme activity, potentially explaining the reduced ET immunoreactivity. There was no correlation of ET immuno-reactivity with the duration of implant use or total number of bleeding days. The marked differences in the ET immunostaining pattern in Norplant users, with their increased risk of abnormal uterine bleeding, suggest that ET may be important in controlling menstrual bleeding. Whether endometrial epithelial cell ET has a role as a mitogen in endometrial repair and regeneration, or as a vasoconstrictor important in the cessation of bleeding following menstruation, remains to be determined.

Cell proliferation is increased in the endometrium of women with endometriosis

OBJECTIVE

To compare the proliferation of endothelial, epithelial, and stromal cells in the endometrium of women with endometriosis and normal controls.

DESIGN

Proliferating cells were identified using the monoclonal antibody antiproliferating cell nuclear antigen. A second antibody (CD34) was used to identify endothelial cells (ECs).

SETTING

University Department of Obstetrics and Gynaecology.

PATIENTS

Women with laparoscopically proven endometriosis, n = 30. Controls were women with a normal pelvis at laparoscopy performed for tubal sterilization or for infertility due to a male factor, n = 27.

MAIN OUTCOME MEASURES

Endothelial cells: proliferative index. Epithelial and stromal cells: semi-quantitative immunostaining score.

RESULTS

The mean EC proliferative index was significantly greater in those with endometriosis compared with controls. This difference was most marked during the proliferative phase of the menstrual cycle. Proliferative phase epithelial and stromal cells demonstrated significantly higher immunostaining scores in endometriosis patients than in controls.

CONCLUSIONS

We have demonstrated increased numbers of proliferating ECs as well as epithelial and stromal cells in proliferative phase endometrium of women with endometriosis. This suggests that the endometrium of these women might have an enhanced ability to implant and survive in ectopic locations.

Hemolysis in primary lipoprotein lipase deficiency

A slight to moderate hemolysis is often present in plasma from patients with primary lipoprotein lipase (LPL) deficiency. To determine the nature of this hemolysis, we measured erythrocyte hypo-osmotic fragility, plasma free hemoglobin, and phospholipid composition in 26 patients with primary LPL deficiency and 21 unrelated controls. In some patients, these investigations were completed by erythrocyte cytoskeletal protein determinations and abdominal echography. Osmotic fragility was similar between control subjects and patients. However, there was a significantly increased concentration of plasma free hemoglobin in primary LPL deficiency (0.282 +/- 0.331 v 0.048 +/- 0.038 g/L in controls, P < .005). In LPL-deficient patients, an increase of plasma lysophosphatidylcholine concentration (12.6% +/- 5.8% v 6.4% +/- 1.9% in controls, P < .0001) was also found. The protein composition of the erythrocyte membrane skeleton was abnormal in some LPL-deficient patients and splenomegaly was present in 12, but these abnormalities did not correlate with plasma free hemoglobin levels. Bilirubin and haptoglobin levels were also within physiologic ranges in these patients, suggesting that the observed hemolysis did not result from hypersplenism. It appears likely that the accumulation of lysophosphatidylcholine was due to an impairment in the reverse metabolic pathway converting lysophosphatidylcholine back to phosphatidylcholine. Collectively, these data, along with a positive correlation between plasma free hemoglobin and lysophosphatidylcholine levels (r = .58, P = .0001), suggest that the hemolysis observed in primary LPL deficiency is mediated to some extent by the abnormally elevated concentration of lysophosphatidylcholine.

Immunohistochemical characterization of human endometrial microvascular basement membrane components during the normal menstrual cycle

The expression of three basement membrane components [collagen IV (CIV), laminin and heparan sulphate proteoglycan (HSPG)] and platelet endothelial cell adhesion molecule (PECAM) were examined by immunohistochemistry in cryostat sections of normal human endometrium. Alkaline phosphatase (ALP) was detected using enzyme histochemistry. Endometrial biopsies from the menstrual (n = 4), mid-late proliferative (n = 5), early-mid secretory (n = 5) and late secretory (n = 5) stages were collected from women with a normal menstrual cycle. At all four stages of the menstrual cycle, CIV, laminin and HSPG were expressed on basement membranes of both vessels and glands whilst PECAM expression was localized specifically to endothelial cells. A similar number of vessels/mm2 stained for CIV and laminin, as well as for PECAM at each stage of the menstrual cycle, demonstrating that all vessels in endometrium stain for these two basement membrane components. By contrast, the number of vessels/mm2 that stained positively for HSPG and ALP was significantly lower, averaging approximately 55% of the total that stained positively for PECAM, CIV and laminin. During the menstrual stage, HSPG staining intensity remained strong in glandular basement membranes but decreased dramatically in vascular basement membranes. ALP activity was variable in both the vessels and glands throughout the four stages of the menstrual cycle studied. This study demonstrates heterogeneity in basement membrane components within the endometrial microvasculature. It is postulated that the disappearance of HSPG from vascular basement membranes may play a role in the process of vascular remodelling during the menstrual stage of the cycle.

Production of an endothelial cell migratory signal in rat endometrium during early pregnancy

Rat endometrial explants were cultured in a three-dimensional collagen/endothelial cell matrix to measure angiogenic activity, as represented by migration of vascular endothelial cells towards the explants. Minimal endothelial cell migratory activity was observed with endometrial explants taken during the four-day oestrous cycle and days 3 and 4 of pregnancy. In contrast, a surge of endothelial cell migration occurred in response to endometrial explants taken from day-5-pregnant rats. Activity was found in explants taken approximately 5 h prior to implantation, but returned to minimal levels by day 6 of pregnancy. Endothelial cell migration remained minimal in response to both implantation and intersite tissue explants taken from days 6 and 7 of pregnancy. Endometrium from ovariectomised rats produced no endothelial cell migratory activity as measured by this technique. However, near preimplantation levels of endothelial cell migratory activity could be induced in ovariectomised rat endometrium by administering progesterone for 72 hours. Oestrogen given in conjunction with progesterone had no additional effect. These results demonstrate the presence of an endometrial signal that controls endothelial cell migration, and demonstrate this activity can be induced by progesterone without the addition of oestrogen.

Current studies on human implantation: a brief overview

Embryo implantation involves a series of complex interactions between the developing embryo and the maternal endometrium. Results of studies with animal models suggest that the uterus must undergo a series of morphological and biochemical changes, mediated primarily by oestrogen and progesterone, before it becomes receptive for successful implantation. At present there is little understanding of the endometrial changes required to achieve endometrial receptivity for implantation in the human. It appears that control of receptivity is not as stringent in the human as in some other species, with IVF data suggesting that the duration of receptivity is at least 4 days, and that successful implantation can occur under a relatively wide range of morphological and ultrastructural conditions. Research on the later stages of implantation, including embryo positioning within the uterus, attachment and invasions, has been almost non-existent in the human. Further studies are critical for a better understanding of this complex process, although human studies will always be limited by ethical constraints.

Immunohistochemical staining of von Willebrand factor in endometrium of women during the first year of Norplant implants use

The mechanisms responsible for Norplant implants-induced menstrual irregularities remain poorly understood. It is unclear whether local changes in endometrial haemostasis are involved. The aim of the present study was to examine the immunohistochemical staining for von Willebrand factor (vWF) in endometrial biopsies taken from 37 women exposed to Norplant implants for 3-12 months and to compare it with 73 controls at various phases of the normal menstrual cycle. The vWF staining intensity was quantified by subjective scoring and by objective computerised colour image analysis. Results from the Norplant implants group were additionally correlated with their bleeding patterns, endometrial histology, and plasma oestradiol (E2) and progesterone (P4) levels. No differences were found between control and Norplant implants subjects in the localization of vWF staining, which was specifically confined to the endothelium of endometrial blood vessels. vWF staining intensity in Norplant implants endometrium was significantly lower than in controls during mid cycle, and reached a mean (+/- SE) level (subjective staining score 2.05 +/- 0.13, n = 37) in the range of the early proliferative and mid secretory phase normal endometrium; nevertheless, it remained significantly higher than that of menstrual and late secretory phase normal endometrium. No significant variations in vWF staining could be related to either the histology of the endometrium or the bleeding pattern of the users. Correlation of vWF staining with either serum E2 or serum P4 prior to biopsy, or to the number of days of Norplant implants exposure revealed no significant relationships. However, vWF staining was positively correlated (r = 0.419, P < 0.01) to the number of bleeding/spotting days within a 90-day reference period prior to biopsies being taken. These results demonstrate that there are major differences in the mechanism responsible for normal menstruation and Norplant implants-induced intermenstrual bleeding and spotting, and show that menstrual disturbances associated with the use of Norplant implants are unlikely to be due to changes in vWF levels in endometrial endothelial cells.

Endometrial endothelial cell proliferation in long-term users of subdermal levonorgestrel

The aim of the present study was to quantify endothelial cell proliferation (a component of angiogenesis) using immunohistochemistry, in the endometrium of users of subdermal levonorgestrel (Norplant). It was postulated that the increased endometrial microvascular density seen in Norplant users, compared to normally cycling women, was associated with an increased rate of endothelial cell proliferation. The results, however, showed that the endometrial endothelial cell proliferative index of Norplant users (0.39 +/- 0.16%; mean +/- SEM) was significantly reduced compared to that seen in normally cycling women (8.99 +/- 1.64). At the same time, total numbers of endometrial endothelial cells per mm2 in Norplant users (317.40 +/- 13.88) were significantly higher than in normally cycling women (223.35 +/- 10.31). It is possible that in the endometrium with levonorgestrel use, there is either a reduced rate of regression of the blood vessels relative to the rest of the tissue, or there is a reduced rate of endothelial cell death or turnover. Peripheral oestrogen and progesterone concentrations, bleeding pattern over the previous 90 days, and the histological appearance of the endometrium did not appear to be associated with the endothelial cell proliferative index. The results suggest that subdermal levonorgestrel use affects the mechanisms that dictate the normal relationship between endometrial blood vessel growth and regression, and the surrounding non-vascular tissue.

An immunohistochemical study of the vascularization of the human Graafian follicle

The wall of the largest Graafian follicle or corpus luteum was biopsied in 22 patients at laparoscopy. Both granulosa and theca cells were contained in 18 samples. These samples were classified as pre-luteinizing hormone (LH) surge (n = 3), LH surge (n = 3), early luteal (n = 3), mid-luteal (n = 4), late luteal (n = 3) and menstrual (n = 2). A double-staining immunohistochemical protocol was used to demonstrate proliferating endothelial cells: mouse-anti-rat-proliferating cell nuclear antigen, for proliferating cells; mouse-anti-human-CD34 antibody for endothelial cells. The percentage of endothelial cells proliferating (proliferation index) and the area of tissue occupied by endothelial cells (areal fraction) were determined for granulosa and theca layers. Intra- and inter-slide coefficients of variation were < 15%. The granulosa layer was avascular until the LH surge subsided. Maximum vascularization was achieved by the mid-luteal phase. The theca endothelial cell proliferation index was constant from pre-LH surge to mid-luteal phases. The mean theca endothelial cell proliferation index for these phases was significantly greater than for the late luteal and menstrual phases. From first appearance in the granulosa layer, endothelial cells had the same proliferation index as the theca endothelial cells, the proliferation index decreasing significantly in both after the mid-luteal phase (P = 0.018). It is concluded that endothelial cell proliferation is unchanged throughout the follicular, early and mid-luteal phases, decreasing significantly in the late luteal phase. By contrast, endothelial cell invasion of the membrane granulosa, presumably in response to a chemotactic stimulus, occurs after the LH surge has subsided.

Vascular endothelial growth factor as capillary permeability agent in ovarian hyperstimulation syndrome

We investigated the role of vascular endothelial growth factor (VEGF) in ovarian hyperstimulation syndrome (OHSS). Two similar peaks of permeability activity were seen in OHSS ascites and liver ascites spiked with recombinant human VEGF (rhVEGF); no activity was seen in control liver ascites. Incubation with rhVEGF antiserum decreased activity in the two OHSS peaks by 79% and 65% and the two spiked liver peaks by 49% and 50%. Control serum produced 24% and 27%, and 17% and 0% reductions, respectively. This is evidence that the major capillary permeability agent in OHSS ascites fluid is VEGF.

Human follicular fluid maturity and endothelial cell chemotaxis

Follicular fluid of varying maturity was collected from the largest Graafian follicle of 23 ovulatory patients during laparoscopy (five blood-stained samples were discarded) and from five patients undergoing oocyte collection for assisted reproduction. The endothelial cell (EC) chemotactic potentials of the samples were tested with bovine aortic ECs in modified Boyden Chambers and an EC density score was determined for each sample. Intra-assay coefficients of variation (CV) varied from 2.9-17%; inter-assay CV was 45%. Therefore, cell density scores were expressed in terms of positive and negative control values from their respective plates. Serum progesterone was positively correlated with EC chemotactic potential (R2 = 14.9%). There was no correlation with day of cycle, follicular diameter, serum luteinizing hormone (LH) or oestradiol, or follicular fluid total protein levels (all R2 < or = 6%). Five subjects were in early and four in mid-follicular phase, seven were in early and two in late LH surge, and there were also five in-vitro fertilization (IVF) specimens. There was a statistically significant difference between the EC chemotactic potential of the five groups by analysis of variance (F = 5.98; P = 0.006). There was no significant difference between the late LH surge and the IVF samples (two-sample t-test). The mean cell density was higher for these two groups than the other three (P < 0.01 in all cases; two-sample t-test). It is concluded that the EC chemotactic potential of human follicular fluid increases after the LH surge and before ovulation.

Endometrial sex steroid receptor expression in women with menorrhagia

OBJECTIVE

To investigate the oestrogen and progesterone receptor distribution in endometrium from reproductive age and perimenopausal women with and without menorrhagia.

DESIGN

A comparative observational study.

SUBJECTS

Forty-five women with objective menorrhagia (27 categorised as reproductive age and 18 as perimenopausal) and a control group of 44 women (31 reproductive age and 13 perimenopausal) with menstrual blood loss of less than 80 ml per period.

MAIN OUTCOME MEASURES

Oestrogen receptor and progesterone receptor semi-quantitative immunostaining scores.

RESULTS

Comparison of control and menorrhagic endometrium in this study (whether from reproductive age or perimenopausal subjects) failed to demonstrate any major differences in either sex steroid receptor mean immunostaining score. The results demonstrated a great degree of variability in sex steroid receptor immunoreactivity between individuals. Irrespective of clinical group, significant increases in immunostaining were demonstrated in the proliferative phase of the cycle for immunoreactivity of oestrogen receptor in glands (P < 0.0005), and stromal (P = 0.002) compartments of endometrium and progesterone receptor immunoreactivity in glands (P = 0.009). Progesterone receptor immunostaining in the stromal compartments did not significantly decline (P = 0.06) in the secretory phase.

CONCLUSIONS

Endometrium from women with objective evidence of menorrhagia is indistinguishable in terms of sex steroid immunoreactivity from endometrium of women with normal monthly blood loss. This pattern of sex steroid receptor immunostaining pattern was maintained into the perimenopausal years.

Endometrial endothelial cell proliferation during the menstrual cycle

Adult endometrium is a tissue in which physiological angiogenesis occurs regularly and provides an accessible source of material for study. Endometrial biopsies and immunohistochemistry were used to test two hypotheses: firstly, that there are peaks of endothelial cell proliferation in human endometrium during the menstrual cycle, and secondly that in-vitro endothelial cell migratory signal production by human endometrium (measured in a previous study) accompanies endothelial cell proliferative activity in vivo. Proliferating cells were identified using anti-proliferating cell nuclear antigen, and endothelial cells were identified using anti-CD34. The method was validated by a smaller, separate study using bromodeoxyuridine incorporation and detection with formalin-fixed biopsies, and comparison with proliferating cell nuclear antigen staining. The main study (n = 50) showed that significant peaks of endometrial endothelial cell proliferation could not be identified, due to the large variability in endothelial cell proliferative activity between individuals at the same stage of the menstrual cycle. Endometrial endothelial cell migratory signal production did not correlate with endothelial cell proliferation (n = 27). Results suggest that blood vessel growth in the endometrium may occur by a process that differs from the traditional concept of angiogenesis, which has been derived mainly from in-vitro or in-vivo experimental studies.

Cytokeratins 8, 18 and 19 in endometrial epithelial cells during the normal menstrual cycle and in women receiving Norplant

Cytokeratins 8, 18 and 19 are members of the cytoskeletal intermediate filament protein family. They are expressed in all simple epithelial tissues, including endometrium, and are recognised as dynamic structures that can be affected by numerous external factors. The Norplant system is a subdermal slow release levonorgestrel implant commonly used as a long-acting progestogen contraceptive. Norplant implants have been shown to have atrophic effects on endometrial epithelial and stromal cells, and cause a range of endometrial bleeding problems among users. The aim of this study is to describe changes in the immunohistochemical expression and distribution of cytokeratins 8, 18 and 19 in endometrial epithelial cells of Norplant implants users and normal menstrual cycle controls. Endometrial biopsies were collected from 65 control normal cycle women and 37 Norplant implants acceptors. The normal menstrual cycle was classified histologically into 9 stages; one menstrual, five proliferative and three secretory. Norplant implants bleeding patterns were categorised into 6 groups according to current World Health Organisation (WHO) definitions; amenorrhoea, frequent bleeding, infrequent bleeding, irregular bleeding, "normal" bleeding, and prolonged bleeding. The tissues were fixed in formalin, embedded in paraffin, and stained immunohistochemically. Semi-quantitative scoring of the staining intensity was performed. Apical versus basal intracellular cytokeratin distribution was also evaluated. The staining intensity was significantly stronger in control endometrial tissue compared to Norplant implants tissue. In control tissues, cytokeratins were predominantly located in the apical region of epithelial cells (52% of biopsies) and in Norplant implants tissues they were predominantly distributed equally between the apical and basal portions of epithelial cells (43% of biopsies). There was no particular cytokeratin distribution pattern associated with the different stages of normal cycle or the different Norplant implants bleeding patterns. It was concluded that long-term exposure to levonorgestrel significantly reduced the cytokeratin expression in endometrial epithelial cells (P < 0.001).

Uterine endothelial cell proliferation before and after embryo implantation in rats

Angiogenesis occurs rarely in normal adult tissues. The female reproductive tract, however, provides several exceptions, including the endometrium during early pregnancy. The aim of this study was to quantify endothelial cell proliferation (a component of angiogenesis) in the rat endometrium at about the time of implantation, using immunohistochemistry with a double staining technique. Proliferating cells were stained using an antibody against proliferating cell nuclear antigen (PCNA; clone PC10), and endothelial cells were stained with a lectin from Griffonia simplicifolia. Results showed that the endothelial cell proliferative index in the endometrium rose significantly from approximately 1% on the first 2 days of pregnancy to 13% on day 3; and continued to rise to 28% on day 5. After embryo implantation, the endometrial endothelial cell proliferative index rose further to 71% on day 7 at embryo sites only; but significantly decreased to basal values at intersites. The endothelial cell proliferative indices in the myometrium and mesometrial triangle remained at basal values during the first 5 days, but increased to approximately 22% at embryo sites only by day 7. We conclude that in the rat: (1) endometrial angiogenesis may be occurring before embryo implantation; (2) endometrial endothelial and stromal cell proliferation occurs concomitantly, except on day 3 when endothelial cell proliferation begins in advance of other stromal cell proliferation; and (3) there are two separate mechanisms controlling uterine endothelial cell proliferation during early pregnancy. The first mechanism is maternally controlled and is apparent throughout the entire endometrium from day 3; and the second mechanism is apparent after implantation in the vicinity of the embryo.