Endometrial vasculature in Norplant users: preliminary results from a hysteroscopic study

The uterine natural killer cell, cytotoxic T lymphocyte, and granulysin levels are elevated in the endometrium of women with nonstructural abnormal uterine bleeding

OBJECTIVE

To examine the expression of uterine natural killer (uNK) cells and cytotoxic T lymphocytes (CTLs) in endometrial biopsies from reproductive-age women with and without nonstructural abnormal uterine bleeding (AUB) and evaluate the expression of granulysin within these cell populations and potential modulation of matrix metalloproteinase (MMP) expression.

DESIGN

Experimental study, retrospective design.

SETTING

Academic research laboratory.

PATIENT(S)

Patients with nonstructural AUB with no other gynecological pathologies and control patients without AUB.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Immunohistochemical analysis of granulysin, CD56 (uNK cell marker), and CD8 (CTL marker) expression as well as granulysin messenger ribonucleic acid (mRNA) expression levels in endometrial biopsy samples. Assessment of granulysin regulation of human endometrial stromal cell MMP-1 and MMP-3 mRNA expression.

RESULT(S)

The numbers of uNK cells and CTLs were significantly greater in endometrial biopsy tissue from women with AUB than those from controls. In accord with the increased expression of uNK cells and CTLs, granulysin expression was significantly greater in endometrial biopsies from patients with AUB than in from controls and colocalized to both cell types but not endometrial stromal or epithelial cells. The increased granulysin protein expression was associated with the increased granulysin mRNA expression in adjacent serial sections from these same samples. The treatment of the human endometrial stromal cell line t-HESC with granulysin resulted in a significant increase in MMP-1 and MMP-3 mRNA expression.

CONCLUSION(S)

In the current study, immunohistochemistry showed an increased expression of uNK cells, CTLs, and granulysin among subjects with AUB compared with that of subjects without AUB, leading to conclusions that disturbances in the balance of immune cells and an increase in granulysin expression may have implications in the pathophysiology of AUB and include enhanced MMP-1 and MMP-3 expression.

Effects of progestin-only contraceptives on the endometrium

INTRODUCTION

The contraceptive activity of synthetic progestins is mediated through three basic mechanisms: (a) An anti-gonadotrophic action leading to the inhibition of ovulation; (b) Changes in cervical mucus characteristics that inhibit sperm penetration and (c) desynchronization of the endometrial picture necessary for implantation.

AREAS COVERED

Mechanisms involved in the progestin-induced endometrium desynchronization are individually reviewed for each of the routes of administration and, whenever possible, by individual members of the various families of synthetic progestin derivatives.

EXPERT OPINION

For contraceptive purposes, progestins are today administered through several routes: orally, as injections, subdermally and via the vagina or the uterine cavity. Given this variety of modalities, their effects may differ, depending on the route of administration, concentration reached at the level of the endometrium and the duration of use. These are characterized by inactivation of the endometrium. Progestin-only contraception provides a safe and effective control of fertility regulation, although, they are associated with the problem of endometrial break through bleeding that may lead to discontinuation. Unfortunately, in spite of a major research effort over two decades, there is not, as yet, an established long-term intervention available to manage bleeding irregularities, making mandatory a deeper understanding of the mechanisms involved is required.

Complications of Subcutaneous Contraception: A Review

Over 62 million women in the United States are of childbearing age and 60% of them use contraception. Subcutaneous contraceptives include implantable contraceptives and subcutaneous injections. Implantable contraception involves subdermal time-release of synthetic progestin, which allows for several years of continuous, highly effective contraception. Its main effects are inhibition of ovulation and thickening of the cervical mucus. Many complications have been associated with subcutaneous contraception, including menstrual disturbances, headache, weight gain, acne, dizziness, mood disturbances, nausea, lower abdominal pain, hair loss, loss of libido, pain at the implant site, neuropathy, and follicular cysts. Using standard search engines, the complications of subcutaneous contraception are reviewed. Patients should be adequately counseled on the possible complications and side effects of subcutaneous contraception to help them make an informed decision when choosing the right contraceptive to meet their needs.

Endometrial breakdown with sustained progesterone release involves NF-κB-mediated functional progesterone withdrawal in a mouse implant model

Irregular uterine bleeding is a major side effect of long-acting progestogen-only contraceptives in women, and is the primary reason women discontinue their use. In this study, a mouse model of endometrial breakdown was established using a subcutaneous progesterone implant to understand how irregular bleeding begins. Although progestogens sustained decidualization, endometrial breakdown was still observed in this model. We, therefore, hypothesized that endometrial breakdown might involve functional progesterone withdrawal. Using co-immunoprecipitation assays, we observed the constitutive activation of nuclear factor kappa-b (NF-κB) p65 and its interaction with the progesterone receptor (PGR); moreover, transcriptional activity of the PGR was also repressed by NF-κB activity in primary mouse and human decidual stromal cells that mimic progesterone maintenance. Yet the ratio of PGR-B to PGR-A was not increased in the mouse model. In vivo comparison of endometrial breakdown induced by progesterone withdrawal to that seen during sustained progesterone exposure, in the presence of NF-κB inhibitors, revealed that NF-κB-mediated functional progesterone withdrawal is involved in endometrial breakdown in this implant model. These data prompt further studies to determine the homology of this functional progesterone withdrawal mechanism in human endometrium. Mol. Reprod. Dev. 83: 780-791, 2016 © 2016 Wiley Periodicals, Inc.

Dilated thin-walled blood and lymphatic vessels in human endometrium: a potential role for VEGF-D in progestin-induced break-through bleeding

Progestins provide safe, effective and cheap options for contraception as well as the treatment of a variety of gynaecological disorders. Episodes of irregular endometrial bleeding or breakthrough bleeding (BTB) are a major unwanted side effect of progestin treatment, such that BTB is the leading cause for discontinued use of an otherwise effective and popular medication. The cellular mechanisms leading to BTB are poorly understood. In this study, we make the novel finding that the large, dilated, thin walled vessels characteristic of human progestin-treated endometrium include both blood and lymphatic vessels. Increased blood and lymphatic vessel diameter are features of VEGF-D action in other tissues and we show by immunolocalisation and Western blotting that stromal cell decidualisation results in a significant increase in VEGF-D protein production, particularly of the proteolytically processed 21 kD form. Using a NOD/scid mouse model with xenografted human endometrium we were able to show that progestin treatment causes decidualisation, VEGF-D production and endometrial vessel dilation. Our results lead to a novel hypothesis to explain BTB, with stromal cell decidualisation rather than progestin treatment per se being the proposed causative event, and VEGF-D being the proposed effector agent.

Decidualized human endometrial stromal cells mediate hemostasis, angiogenesis, and abnormal uterine bleeding

Factor VII binds trans-membrane tissue factor to initiate hemostasis by forming thrombin. Tissue factor expression is enhanced in decidualized human endometrial stromal cells during the luteal phase. Long-term progestin only contraceptives elicit: 1) abnormal uterine bleeding from fragile vessels at focal bleeding sites, 2) paradoxically high tissue factor expression at bleeding sites; 3) reduced endometrial blood flow promoting local hypoxia and enhancing reactive oxygen species levels; and 4) aberrant angiogenesis reflecting increased stromal cell-expressed vascular endothelial growth factor, decreased Angiopoietin-1 and increased endothelial cell-expressed Angiopoietin-2. Aberrantly high local vascular permeability enhances circulating factor VII to decidualized stromal cell-expressed tissue factor to generate excess thrombin. Hypoxia-thrombin interactions augment expression of vascular endothelial growth factor and interleukin-8 by stromal cells. Thrombin, vascular endothelial growth factor and interleukin-8 synergistically augment angiogenesis in a milieu of reactive oxygen species-induced endothelial cell activation. The resulting enhanced vessel fragility promotes abnormal uterine bleeding.

Effects of doxycycline on serum and endometrial levels of MMP-2, MMP-9 and TIMP-1 in women using a levonorgestrel-releasing subcutaneous implant

BACKGROUND

Endometrial spotting and/or bleeding (ESB) occurs in levonorgestrel subcutaneous implant (LNG SI) users. Matrix metalloproteinases (MMPs) may play a role in ESB.

STUDY DESIGN

Women between 18 and 40 years with regular menstrual cycles had a baseline evaluation followed by LNG SI insertion and randomization to doxycycline (DOX; 20 mg) or placebo (PL) twice a day. MMP-2, MMP-9 and tissue inhibitor of MMP-1 (TIMP-1) in serum and the endometrium were estimated at baseline and at 1, 3 and 6 months after insertion.

RESULTS

LNG increased serum MMP-9, while DOX decreased MMP-9 levels compared to PL after 1 month (p<.05). DOX decreased endometrial MMP-9 at 1 and 6 months compared to baseline and PL (p<.05). DOX increased endometrial TIMP-1 at 6 months compared with baseline and PL (p<.05). MMP-2 levels were unchanged.

CONCLUSION

LNG SI increased serum MMP-9 and TIMP-1 levels, while DOX decreased both serum and endometrial MMP-9 levels.

Stimulation of epithelial repair is a likely mechanism for the action of mifepristone in reducing duration of bleeding in users of progestogen-only contraceptives

Many women using progestogen (P)-only contraceptives experience uterine bleeding problems. In clinical trials, a single low dose of mifepristone, given to Implanon users at the beginning of a bleeding episode reduced the number of bleeding days by ∼50% compared with controls. In this study, a single dose of mifepristone was administered to etonogestrel (ENG)-exposed pseudo-pregnant mice, 5 days after artificial decidualization was induced when the endometrium showed signs of bleeding. Control mice received vehicle alone. Mice were culled 12-, 18-, 24- and 48-h post-treatment. In the continued presence of ENG, a single dose of mifepristone stimulated tissue breakdown followed by very rapid repair: most treated tissues were fully restored to the pre-decidualized state by 48 h post-treatment. During repair, proliferating cells (Ki67 immunostained) were localized to a band of cells around the basal area in breaking down tissues and to the repairing luminal epithelium and glands. Progesterone receptor-positive cells were largely localized to the basal area of the breaking down tissue in treated mice compared with decidual cells in controls. Oestrogen receptor-positive cells were observed in the repairing luminal epithelium and glands compared with the decidua and the basal region in control tissues. It is concluded that mifepristone treatment stimulates rapid restoration of luminal epithelial integrity: such action may be a key event in reducing the number of bleeding days observed in women using Implanon who were treated with a single dose of mifepristone.

Endometrial structural and inflammatory changes with exogenous progestogens

Safe and effective contraception is an international public health priority. The long-acting progestogen-only contraceptives are used by over 20 million women worldwide but their main drawback is abnormal uterine bleeding. Such bleeding arises owing to structural and inflammatory changes which compromise endometrial microvascular and epithelial integrity. The molecular and structural changes that lead to the vessel and surface epithelial fragility, and hence the side effect of abnormal uterine bleeding commonly seen with exogenous progestogen use, might be lessened by short-term treatments shown to shorten bleeding episodes.

Effect of mifepristone on the expression of endometrial secretory leukocyte protease inhibitor in new medroxyprogesterone acetate users

The effect of mifepristone on the expression of secretory leukocyte protease inhibitor (SLPI) in the endometrium of women using depot medroxyprogesterone acetate (DMPA) was investigated in this randomized, placebo-controlled trial. The study showed that the administration of DMPA led to a substantial inhibition of endometrial SLPI protein and mRNA, and that the addition of mifepristone to DMPA-exposed endometrium partially restored the expression of glandular SLPI.

Endometrial effects of intrauterine levonorgestrel

Local intrauterine delivery of levonorgestrel (LNG) results in extensive decidualization of endometrial stromal cells, atrophy of the glandular and surface epithelium and changes in vascular morphology (suppression of spiral artery formation and presence of large dilated vessels). With endometrial exposure to LNG, there is down-regulation of sex steroid receptors in all cellular components. As a consequence of endometrial sex steroid receptor down-regulation, there is perturbation of progesterone-regulated locally acting mediators, and the integrity of blood vessel walls is disturbed. Thus, intrauterine LNG administration results in modulation of local mediators regulating endometrial function. To date, no single factor has been identified where the expression correlates closely with unscheduled breakthrough bleeding (BTB). BTB is a common side effect and reason for discontinuation of LNG-IUS use. Much remains to be determined about the mechanisms involved in suppression of menstruation, BTB episodes and the local endometrial environment with local LNG administration.

Spontaneous development of endometrial venous malformation: diagnosis with color Doppler sonography

We report the case of a spontaneous development of venous malformation within the endometrium of a patient with adenomyosis who was on oral contraceptives for a prolonged period of time. This vascular abnormality was incidentally identified and diagnosed with color Doppler ultrasound when the patient was referred for pelvic ultrasound for her symptoms related to adenomyosis. The vascular abnormality was characterized as venous malformation based on its Doppler tracing. The possible causes of its spontaneous development are discussed.

Long-term progestin-only contraceptives result in reduced endometrial blood flow and oxidative stress

CONTEXT

Because of their safety and efficacy, long-term progestin-only contraceptives (LTPOCs) are well-suited for women with restricted access to health care. However, abnormal uterine bleeding (AUB) causes half of all users to discontinue therapy within 12 months. Endometria of LTPOC-treated patients display aberrant angiogenesis with abnormally enlarged, thin-walled, fragile blood vessels, inflammation, and focal hemorrhage. In this study, similar effects were observed with a new third-generation implantable LTPOC.

OBJECTIVE

We hypothesized that LTPOC reduces uterine and endometrial blood flow, leading to hypoxia/reperfusion, which triggers the generation of reactive oxygen species. The latter induce aberrant angiogenesis, causing AUB.

DESIGN

Endometrial perfusion was measured by laser-Doppler fluxmetry in women requesting LTPOCs. Endometrial biopsies were obtained for in vivo and in vitro experiments.

SETTING

The study was conducted in the Yale University School of Medicine and Family-Planning Center in Western Australia.

PATIENTS

Seven women 18 yr or older requesting implantable LTPOCs were recruited in Western Australia.

INTERVENTION

Women received etonorgestrel implants.

MAIN OUTCOME

LTPOC treatment resulted in reduced endometrial perfusion and increased endometrial oxidative damage.

CONCLUSIONS

We propose that LTPOCs result in hypoxia reperfusion, which leads to aberrant angiogenesis resulting in AUB.

Endometrial histology, microvascular density and caliber, and matrix metalloproteinase-3 in users of the Nestorone®-releasing contraceptive implant with and without endometrial breakthrough bleeding

OBJECTIVE

This descriptive study evaluated endometrial histology, microvascular density and caliber, and quantification of matrix metalloproteinase (MMP-3) expression in long-term users of the Nestorone (NES)-releasing implant who presented or not endometrial breakthrough bleeding (BTB).

METHODS

Endometrial biopsies were obtained from 32 healthy women with unpredictable BTB. The quantitative analysis was performed only in 20 samples.

RESULTS

The mean duration of use of the implant among the 14 women with BTB was 19.6+/-1.0 months, and the other six women had used the implant for 17.7+/-2.3 months (mean+/-S.E.M.). Histological analysis of the endometrial tissue showed a predominance of progestogenic pattern followed by atrophic and proliferative endometrium in both groups. Mucosal breakdown and glandular pseudostratification were observed in half of the cases. Endometrial vascular density was 73.1+/-10.0 and 57.5+/-24.1 vessels/mm(2), and maximum vessel diameter was 923.3+/-86.0 and 1038.0+/-404 microm (mean+/-S.E.M.) in the group with and without BTB, respectively, without significance, and the rate of cells expressing MMP-3x1000 counted stromal cells was 155.8+/-24.8 and 127.0+/-19.0 (mean+/-S.E.M.) in both groups, respectively, without significance.

CONCLUSIONS

This study provides information about some endometrial aspects of women using NES in contraceptive implants. In addition, the endometrium was similar during long-term use of NES-releasing contraceptive implants in women with and without endometrial bleeding.

The effect of tranexamic acid for treatment of irregular uterine bleeding secondary to Norplant use

OBJECTIVE

The purpose of this study is to evaluate the effects of tranexamic acid and placebo on controlling irregular uterine bleeding secondary to Norplant use.

MATERIALS AND METHODS

A prospective randomized, double-blind, placebo-controlled trial was conducted. Sixty-eight Norplant users who had irregular bleeding were randomly allocated into two groups. A total of 34 users received tranexamic acid 500 mg twice a day for 5 days; the placebo was given to the other 34 users in the same manner. The total number of days of bleeding and spotting and the percentage of women whose irregular uterine bleeding was stopped was analyzed at the end of weeks 1 and 4.

RESULTS

In the follow-up period (4 weeks after the initial treatment), a bleeding-free interval of > 20 days was found in 58.8% of the subjects treated with tranexamic acid and in 76.5% treated with placebo (p = .12). The percentage of subjects whose irregular uterine bleeding stopped during week 1 after the initial treatment was significantly higher in the tranexamic acid group than those in the placebo group (64.7% vs. 35.3%, p = .015). The mean number of bleeding/spotting days was not significantly different between the groups (15.4 vs. 12.7 days, p = .182).

CONCLUSIONS

Tranexamic acid for 5 days appears to be an effective treatment for irregular uterine bleeding associated with Norplant use only while it is being used. However, treatment for 5 days does not seem to provide long-term benefit.

Progestogen only contraception and endometrial break through bleeding

Progestogen only contraceptives (POC) provide a safe and effective method of fertility regulation. Unfortunately, they are commonly associated with the problem of endometrial break through bleeding (BTB), often leading to discontinuation of use. An increase in endometrial vascular fragility has been demonstrated as an important mechanism that contributes to BTB but our understanding of the interaction between exogenous steroid use and endometrial vasculature remains incomplete. This review sets out to describe a number of commonly used POC, their effects on endometrial morphology and possible molecular and cellular mechanisms that may lead to unscheduled bleeding.

Increased serum levels of nitric oxide metabolites among users of levonorgestrel-releasing implants [corrected] a possible role in progestin-induced bleeding

BACKGROUND

Nitric oxide (NO) is a potent angiogenic and vasodilator factor that could be involved in progestin-induced bleeding. This study aimed to assess possible changes in the serum levels of NO metabolites in users of levonorgestrel-releasing implants (LNG-implants) [corrected] and to identify any correlation between some of their clinical characteristics and NO metabolite levels.

METHODS

This cross-sectional study included 37 LNG-implants [corrected] users; a single 5 ml venous blood was collected at different periods of [corrected] use. Women were divided into users with acceptable menstrual bleeding (n 5 13) [corrected] and those having abnormal bleeding patterns (n 5 24) [corrected] The controls are 13 age-matched healthy women; they were fertile, had regular menstruation and did not use any contraceptive method in the previous 3 months. NO was determined by the evaluation of its oxidation products (nitrites and nitrates) where the nitrates were reduced to nitrites with cadmium filings; total serum concentrations of nitrites were measured by using the Griess reaction.

RESULTS

The mean serum levels of NO metabolites were significantly higher in the LNG-implants [corrected] users than in the controls (mean+/-SE) 34.9+/-11.3 versus 6.1+/-1.5 mumol/l (P<0.001) [corrected] The mean serum levels of NO metabolites were significantly higher in the LNG-implants [corrected] users with abnormal bleeding patterns than in those with normal bleeding patterns (mean+/-SE) 41.3+/-7.4 versus 23.2+/-5.8 mumol/l (P<0.001) [corrected] There was a positive correlation between NO levels and both prolonged spotting and heavy/prolonged bleeding days (P<0.001 and P<0.01, respectively) and negative correlation between NO levels with the duration of use and length of the menstrual cycle (P<0.05).

CONCLUSION

The significantly increased serum levels of NO metabolites among LNG-implants [corrected] users may primarily reflect an increase in its endometrial production, possibly secondary to its increased liberation by systemic vascular endothelium. This may result in enhanced endometrial angiogenesis and vascular dilatation which can induce and perpetuate abnormal excessive/prolonged uterine bleeding.

A three-dimensional study of endometrial microvessels in women using the contraceptive subdermal levonorgestrel implant system, norplant®

Recent evidence points towards a substantial disturbance of the process of angiogenesis within the endometrium in women who are exposed continuously to low dose contraceptive progestogens. This results in the patchy appearance of abnormally small and abnormally large, thin-walled vessels in the superficial regions of exposed endometrium. Three-dimensional pictures were developed from digitised images of serial tissue sections of endometrium in which microvascular endothelial cells were labelled with antibodies to the endothelial cell surface antigen, CD34 and their basement membranes labelled with anti-Collagen IV antibodies. Microvessels from endometrium exposed to continuous low-dose levonorgestrel from a subdermal implant system (Norplant) displayed considerable variations in size and shape. No spiral arterioles were identified. Some microvessels showed considerable dilatation, distortion and variability in the presence of surrounding basement membrane components. Other endothelial structures included narrow, solid cords of endothelial cells, without basement membranes, which often connected with normal or abnormal vessels containing lumens. Some areas, especially deeper in the tissue, contained microvessels of normal size and shape surrounded by basement membrane. These images have revealed an overall picture of great variability in superficial endometrial vascular structures in some women using a low-dose levonorgestrel implant system which appears substantially different from that seen in normal endometrium.

Effects of levonorgestrel, medroxyprogesterone acetate, norethindrone, and 17β-estradiol on vascular endothelial growth factor isomers 121 and 165 in Ishikawa cells

OBJECTIVE

To determine the effect of 17beta-E(2), levonorgestrel, medroxyprogesterone acetate, and norethindrone on the expression of vascular endothelial growth factor (VEGF) isoforms 121 and 165 in Ishikawa cells in vitro.

DESIGN

Prospective basic research study.

SETTING

Basic research laboratory.

PATIENT(S)

None.

INTERVENTION(S)

Ishikawa cells were cultured in vitro. After 24 hours' incubation in serum-free media, 1.0, 0.1, and 0.01 microM concentrations of E(2), levonorgestrel, medroxyprogesterone acetate, and norethindrone were added for a further 24 hours of incubation.

MAIN OUTCOME MEASURE(S)

Isolation and identification of VEGF isoforms 121 and 165 using semiquantitative polymerase chain reaction, gel electrophoresis, with beta-actin as an internal control.

RESULT(S)

Estradiol stimulated VEGF isoforms 121 and 165. The progestins studied increased mRNA for VEGF isoforms 121 and 165 at all doses. Medroxyprogesterone acetate resulted in the greatest increase in both VEGF 121 and 165 compared with norethindrone and levonorgestrel.

CONCLUSION(S)

Estradiol and progestins increased VEGF 121 and 165 isoform mRNA in Ishikawa cells in vitro. We hypothesize that differences in VEGF expression may be associated with the irregular bleeding during progestin use in clinical situations.

Insertion of Mirena after Endometrial Resection in Patients with Adenomyosis

STUDY OBJECTIVE

To evaluate the efficacy of Mirena, a levonorgestrel-releasing intrauterine device, after endometrial resection for treatment of menorrhagia caused by adenomyosis.

DESIGN

Open, randomized, observational study (Canadian Task Force classification II-2).

SETTING

Private hospital.

PATIENTS

Ninety-five women.

INTERVENTION

Endometrial resection, after which control patients received no further treatment and study patients had Mirena inserted immediately after the procedure.

MEASUREMENTS AND MAIN RESULTS

The rate of amenorrhea after 1 year was significantly higher in the Mirena group. Nineteen percent of women in the control group had a second procedure to control bleeding compared with none in the Mirena group.

CONCLUSION

Insertion of Mirena after endometrial resection is effective treatment for menorrhagia caused by adenomyosis and has very few adverse effects.

Human uterine vascular structures in normal and diseased states

Menstrual bleeding disorders are one of the most common problems presenting to the gynaecologist. There is increasing evidence that alterations in human uterine vascular structures are associated with spontaneous and sex steroid-induced changes in menstrual bleeding patterns. This article will discuss the normal anatomy and physiology of uterine vascular growth, breakdown, and repair and will indicate where altered anatomy and function may contribute to menstrual disorder. In particular, impact of low-dose progestogens on the endometrial vasculature and endometrial vascular fragility will be discussed. Disturbances of myometrial vascular growth and remodeling, including fibroids, adenomyosis, implantation, and arterio-venous malformations will also be addressed.

Vaginal bleeding disturbances and implantable contraceptives

Implantable contraceptives allow safe and effective fertility regulation for up to 5 years. Currently available devices release low doses of progestogens. Disruption of vaginal bleeding patterns is almost inevitable, particularly during the initial months of use. Irregular and prolonged bleeding as well as amenorrhea are common. Irregular bleeding is unpopular with most women and unacceptable to some. This review describes the vaginal bleeding disturbances induced by modern implantable contraceptives and discusses the implications of these in terms of method use and discontinuations. The cause of the irregular bleeding is not fully understood, but recent evidence suggests that an increase in endometrial vascular fragility might precipitate vessel breakdown and, hence, breakthrough bleeding. This review discusses this evidence and outline the possible mechanisms underlying breakthrough bleeding associated with implantable contraceptives. In addition, therapies for bleeding disturbances are described and their efficacy reviewed.

Endometrial bleeding in hormone replacement therapy users: preliminary findings regarding the role of matrix metalloproteinase 9 (MMP-9) and tissue inhibitors of MMPs

OBJECTIVE

To establish the effect of hormone replacement therapy (HRT) on the expression of matrix metalloproteinase 9 (MMP-9) and the tissue inhibitor of MMPs, TIMP-1, in the endometrium of postmenopausal and perimenopausal women.

DESIGN

Prospective observational study.

SETTING

United Kingdom teaching hospital.

PATIENT(S)

Thirty-one perimenopausal and postmenopausal HRT recipients, with a control group of eight postmenopausal women not undergoing HRT.

INTERVENTION(S)

Prospective record of bleeding patterns and endometrial biopsy.

MAIN OUTCOME MEASURE(S)

Endometrial histology, bleeding patterns, MMP-9, and TIMP-1 expression.

RESULT(S)

MMP-9 and TIMP-1 are expressed in benign postmenopausal endometrium. Expression of both molecules is reduced in HRT recipients compared with non-HRT recipients.

CONCLUSION(S)

Exposure to HRT appears to alter endometrial expression of MMP-9 and TIMP-1 and also the local balance between these molecules. This alteration may promote breakdown of the endometrial extracellular matrix and blood vessels and hence bleeding.

Clinical implications of disturbances of uterine vascular morphology and function

Menstrual disturbances are one of the most common problems presenting to the gynaecologist. In order for the endometrium to bleed, vessels must break down. Disruption in the regulation of endometrial vascular growth and function has been found in association with spontaneous and sex steroid-induced disturbances of menstrual bleeding. Although circulating oestrogens and progestogens influence the endometrial vessels, this effect appears to be indirect, and regulation is primarily via local factors. Deficient vasoconstriction and haemostasis with excessive fibrinolysis is seen in menorrhagia. Breakthrough bleeding in users of progestogen-only contraceptives is associated with increased superficial vascular fragility and disruptions in the supporting basement membrane. Blood vessels in uterine fibroids are abnormal in distribution and appearance. Adenomyosis is also commonly associated with menstrual disturbance, and alterations in vascular distribution suggest altered angiogenesis. Successful human embryo implantation requires endometrial vascular breakdown. Excessive thrombosis associated with the antiphospholipid syndrome may interfere with this re-modelling and compromise implantation. Arteriovenous malformations are a rare but important cause of excessive or irregular vaginal bleeding. Abundant vessels with abnormal morphology, associated with aberrant angiogenesis can be seen, and embolization of these vessels may be an effective conservative treatment. Improved understanding of the regulation of the uterine vasculature is likely to lead to targeted therapies to prevent unscheduled vascular breakdown and to control menstrual disturbance at an endometrial level.

Superficial endometrial vascular fragility in Norplant users and in women with ovulatory dysfunctional uterine bleeding

The aim of this study was to develop an objective test for superficial endometrial vascular fragility at hysteroscopy, and to apply this test to women using Norplant((R)) for contraception and to women with ovulatory dysfunctional uterine bleeding (DUB). A prospective observational study was carried out in 34 Norplant users and 20 women with menorrhagia due to ovulatory DUB. Superficial endometrial vascular fragility was assessed at hysteroscopy by observing the source and extent of frank and subepithelial bleeding during controlled collapse and redistension of the uterine cavity. Superficial endometrial blood vessels were more fragile in Norplant users compared to women with DUB (chi(2) = 11.60, P = 0.02). Superficial endometrial petechiae (chi(2) = 37.9, P < 0.0001) and ecchymoses (chi(2) = 42.2, P = 0.0001) were more frequently observed in the Norplant users than in the menorrhagia group. In Norplant users, superficial endometrial vascular fragility was increased in those with frequent bleeding or spotting during the past 30 days (chi(2) = 6.15, P = 0.01), and in those who were examined during a bleeding episode (chi(2) = 5.3, P = 0.02). Fragility was increased in the menorrhagia group during the perimenstrual period (days 24 to 05; chi(2) = 12.83, P = 0.01). There was no obvious relationship between subepithelial bleeding and circulating concentrations of oestradiol and progesterone.

Matrix metalloproteinase-1 and -3 and mast cells are present in the endometrium of women using progestin-only contraceptives

Progestin-only contraceptives are associated with menstrual bleeding disturbances; a major reason why these agents are discontinued. The pathogenesis of such abnormal uterine bleeding associated with progestin-only contraceptives remains ill-defined. Matrix metalloproteinases (MMP)s and mast cells (MC)s are postulated to be involved in endometrial breakdown observed in normal menstruation. In this study comparisons were made of the immunolocalization of MMP-1 and -3 and MC in endometrium from women using Norplant or depot medroxyprogesterone acetate (DMPA) with normal controls. Positive MMP immunostaining was observed focally in stromal cells and adjacent extracellular matrix. Quantitative assessment revealed significantly higher MMP-1 immunostaining associated with the use of Norplant compared with DMPA or menstrual phase controls. Endometrial MMP-1 immunostaining in DMPA users was similar to that in menstrual controls. Positive MMP-3 immunolocalization was observed in a minority of endometrial samples. Activated MC, shown by the presence of extracellular MC tryptase, predominated in the endometrium of Norplant and DMPA users as also observed in menstrual phase controls. There was no correlation between MMP immunostaining, number of MC and number of bleeding days reported. These results indicate that in women using progestin-only contraceptives, endometrial MMP-1, -3 and MC demonstrate similarities to menstrual phase controls but also variation with different progestins.

Out-patient hysteroscopy in asymptomatic postmenopausal women

OBJECTIVE

To determine the prevalence of uterine and endometrial abnormalities in normal postmenopausal women and assess the accuracy of subjective hysteroscopic appearances and endometrial histology following 12 weeks of hormonal treatment.

DESIGN

A multicentered randomized double-blind placebo-controlled trial in which the volunteers received conjugated equine estrogen 0.625 mg, selective estrogen receptor modulator (in one of two doses) or placebo.

SETTING

Out-patient endoscopy unit in a large teaching hospital.

METHODS

Out-patient hysteroscopy and endometrial biopsy.

RESULTS

Forty-eight women had a hysteroscopy and endometrial biopsy: eight (16.6%; 95% confidence interval, CI 6-27%) women had intrauterine polyps and 38 (79.2%) women had normal hysteroscopies. Thirty-five women had a repeat endometrial assessment with hysteroscopy and, for the detection of proliferative endometrium (prevalence 22.8%), a sensitivity of 87.5%, a specificity of 74%, a negative predictive value of 95% and a positive predictive value of 50% were observed. There was a good proportion of agreement, 0.77 (95% CI 0.63-0.91), but a kappa score of 0.486 revealed only a moderate level of agreement. The likelihood ratios for proliferative endometrium were: LHR+ = 3.38 (fair), and LHR- = 0.17 (moderate).

CONCLUSIONS

Hysteroscopic assessment of the uterine cavity is efficient in the detection of pathological intrauterine lesions, but is only moderately successful in determining physiological changes in the endometrium. This study defines a standard of observational statistics for out-patient hysteroscopy in relation to normal endometrial histology in postmenopausal women who may have been ingesting exogenous estrogens.

The effect of mefenamic acid on controlling irregular uterine bleeding secondary to Norplant use

The aim of this double-blind, placebo-controlled study was to evaluate the effect of mefenamic acid and placebo on controlling irregular uterine bleeding secondary to Norplant use. A total of 67 Norplant users attending the Family Planning Clinic of Chulalongkorn Hospital all had irregular bleeding. These women were randomly allocated into two groups. A total 34 users received mefenamic acid, 500 mg twice a day for 5 days, and placebos were given to the other 33 in the same manner. The total days of bleeding and spotting and the percentage of women in whom bleeding was stopped were analyzed in weeks 1 and 4. The percentage of subjects in whom bleeding was stopped during week 1 after initial treatment was significantly higher in the mefenamic acid group than the placebo group (76%, 27%; p < 0.001). In the follow-up period (4 weeks after initial treatment), a bleeding-free interval of > 20 days was found in 68% of the subjects treated with mefenamic acid and 33% treated with the placebo; the mean number of bleeding/spotting days was lower with mefenamic acid treatment (11.6 and 17.2 days; p < 0.05). The difference was statistically significant. It is concluded that mefenamic acid was more effective than placebo in short-term control of irregular bleeding and spotting associated with Norplant use.

A longitudinal study of changes in endometrial microvascular density in Norplant implant users

This study aimed to investigate the effects of the subdermal levonorgestrel contraceptive implant Norplant on endometrial vascular density at different durations of exposure, and the relationship between endometrial histology, vascular density, and bleeding patterns. A prospective controlled trial of Norplant implant users compared endometrial vascular density in biopsies taken before and after Norplant implant insertion. A total of 34 women with regular menstrual cycles requesting long-term contraception were recruited at the Sydney Centre for Reproductive Health Research, Australia. A significant increase in mean endometrial microvascular density was observed from as early as 3 weeks after insertion of Norplant implants. Vascular density was increased from a control secretory phase value of 189.6 (7.0 vessels/mm2 (+/- SEM) to 253.80 +/- 7 vessels/mm2 at 2-13 weeks of Norplant implant exposure (t ratio = 2.08, p = 0.01) and 212.7 +/- 12.9 vessels/mm2 at 14-42 weeks of exposure (t ratio = 2.03, p = 0.02). In those with atrophic endometrium, or in whom myometrium and basalis only were found in biopsies (20 of 66, 30%), mean endometrial vascular density was increased at 273.1 +/- 16.1 vessels/mm2 compared with 210.9 +/- 11.7 vessels/mm2 in other histological groups (F ratio = 9.74, p = 0.0028). Bleeding and spotting in the previous 30 days were less common in those with this histological appearance at a mean of 4.95 days compared with 8.22 days. This is the first study to assess endometrial vascular density in the early months of Norplant implant use. The findings suggest that the endometrial vasculature is profoundly altered in the early months of Norplant implant exposure when bleeding problems are most common.