Differential elevation of matrix metalloproteinase expression in women exposed to levonorgestrel-releasing intrauterine system for a short or prolonged period of time

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.

Giant exophytic cystic adenomyosis with a levonorgestrel containing intrauterine device out of the uterine cavity after uterine myomectomy: A case report

BACKGROUND

A cystic lesion arising from the myometrium of the uterus, termed as cystic adenomyosis, has chocolate-like, thick viscous contents and contains various amounts of endometrial stroma below the glandular epithelium. It is an extremely rare type of adenomyosis.

CASE SUMMARY

Herein, we report an unusual case of a giant cystic mass in the pelvic cavity after uterine myomectomy. The patient complained of abnormal uterine bleeding and severe dysmenorrhea. After a levonorgestrel-containing intrauterine device (LNG-IUD) was inserted, her symptoms were greatly alleviated. However, the LNG-IUD was detected in the cystic cavity during the follow-up. For fear of the intrauterine device migrating into and damaging the surrounding viscera, surgical treatment was proposed. Therefore, laparoscopic resection of the lesion and removal of the LNG-IUD were performed and cystic adenomyosis with an LNG-IUD out of the uterine cavity was diagnosed.

CONCLUSION

We believe that myomectomy breaking through the endometrial cavity may have been a predisposing factor for the development of cystic adenomyosis in this case.

Immunologic evaluation of the endometrium with a levonorgestrel intrauterine device in solid organ transplant women and healthy controls

OBJECTIVE

The objective was to describe the endometrial milieu of stable transplant patients and healthy women before and after levonorgestrel intrauterine system (LNG-IUS) insertion.

STUDY DESIGN

Women between 18 and 45 years of age desiring LNG-IUS insertion were enrolled with a 2:1 ratio of healthy to stable solid organ transplant patients. The first visit entailed a blood draw, uterine lavage and endometrial biopsy followed by LNG-IUS insertion. Follow-up visit involved a repeat serum draw, uterine lavage and endometrial biopsy. Cytokine levels were measured in the uterine lavage and serum by quantifying inflammatory biomarkers. Immunohistochemistry staining was performed on the endometrial tissue to measure macrophage levels. Statistical analysis included a nonparametric analysis that compared medians of the marker levels before and after intrauterine device (IUD) insertion within the group and between the two groups.

RESULTS

Sixteen participants completed the study: 5 solid organ transplant patients and 11 healthy patients. For the serum, there were no marked changes in the cytokines or soluble receptor levels in either group after IUD insertion. However, in the uterine lavage, there was an increase in cytokine levels post-IUD insertion for both healthy and transplant women. For the endometrial tissue, there was evidence of macrophage activity in both groups after device insertion.

CONCLUSIONS

This pilot study investigated the uterine environment of the transplant patient population. Findings have pointed to the strong local inflammatory response following LNG-IUS insertion for the transplant recipients. In addition, these preliminary findings will help power a larger study that can investigate the safety and effectiveness of the IUD in this patient population.

IMPLICATIONS

Findings from this pilot study suggest that the IUD is inducing a local inflammatory reaction in the uterus of the transplant patient as in the healthy control. A larger study can build on these preliminary results to pursue the efficacy and safety of IUD use among solid organ transplant patients.

Effect of oral contraceptives and doxycycline on endometrial MMP-2 and MMP-9 activity

OBJECTIVES

To describe the effect of combined oral contraceptives (COCs) on matrix metalloproteinases MMP-2 and MMP-9 activity and compare MMP activity in women taking a COC with or without doxycycline.

STUDY DESIGN

Subjects (n=20) underwent endometrial biopsies (1) in the late luteal phase of a baseline cycle prior to initiating COCs, (2) on days 19-21 while taking COCs in a standard 28-day cycle (7-day hormone-free interval) and (3) on days 26-28 while taking active COCs continuously for a 28-day cycle. During the continuous COC cycle, they were randomized to receive daily subantimicrobial dose doxycycline 40mg or placebo.

RESULTS

Compared to baseline, COC treatment increased MMP-2 (p<.001) and MMP-9 (p<.001). MMP activity was lower in subjects taking a COC with doxycycline compared to those receiving placebo although only significantly lower for MMP-2 latent form (p=.002).

CONCLUSIONS

Unscheduled bleeding with COCs may be the result of increased endometrial MMPs. Sample size limitations prevent us from determining how doxycycline affects MMP activity in COC users.

Progestin-Containing Contraceptives Alter Expression of Host Defense-Related Genes of the Endometrium and Cervix

Epidemiological studies indicate that progestin-containing contraceptives increase susceptibility to HIV, although the underlying mechanisms involving the upper female reproductive tract are undefined. To determine the effects of depot medroxyprogesterone acetate (DMPA) and the levonorgestrel intrauterine system (LNG-IUS) on gene expression and physiology of human endometrial and cervical transformation zone (TZ), microarray analyses were performed on whole tissue biopsies. In endometrium, activated pathways included leukocyte chemotaxis, attachment, and inflammation in DMPA and LNG-IUS users, and individual genes included pattern recognition receptors, complement components, and other immune mediators. In cervical TZ, progestin treatment altered expression of tissue remodeling and viability but not immune function genes. Together, these results indicate that progestins influence expression of immune-related genes in endometrium relevant to local recruitment of HIV target cells with potential to increase susceptibility and underscore the importance of the upper reproductive tract when assessing the safety of contraceptive products.

The importance of the macrophage within the human endometrium

The human endometrium is exposed to cyclical fluctuations of ovarian-derived sex steroids resulting in proliferation, differentiation (decidualization), and menstruation. An influx of leukocytes (up to 15% macrophages) occurs during the latter stages of the menstrual cycle, including menses. We believe the endometrial macrophage is likely to play an important role during the menstrual cycle, especially in the context of tissue degradation (menstruation), which requires regulated repair, regeneration, and phagocytic clearance of endometrial tissue debris to re-establish tissue integrity in preparation for fertility. The phenotype and regulation of the macrophage within the endometrium during the menstrual cycle and interactions with other cell types that constitute the endometrium are currently unknown and are important areas of study. Understanding the many roles of the endometrial macrophage is crucial to our body of knowledge concerning functionality of the endometrium as well as to our understanding of disorders of the menstrual cycle, which have major impacts on the health and well-being of women.

The endocrine and paracrine control of menstruation

During the reproductive life, the human endometrium undergoes cycles of substantial remodeling including, at menstruation, a massive but delimited tissue breakdown immediately followed by scarless repair. The present review aims at summarizing the current knowledge on the endocrine and paracrine control of menstruation in the light of recent observations that undermine obsolete dogmas. Menstruation can be globally considered as a response to falling progesterone concentration. However, tissue breakdown is heterogeneous and tightly controlled in space and time by a complex network of regulators and effectors, including cytokines, chemokines, proteases and various components of an inflammatory response. Moreover, menstruation must be regarded as part of a complex and integrated mechanism of tissue remodeling including features that precede and follow tissue lysis, i.e. decidualization and immediate post-menstrual regeneration. The understanding of the regulation of menstruation is of major basic and clinical interest. Indeed, these mechanisms largely overlap with those controlling other histopathological occurrences of tissue remodeling, such as development and cancer, and inappropriate control of menstrual features is a major potential cause of two frequent endometrial pathologies (i.e. abnormal uterine bleeding and endometriosis).

Regulation of matrix metalloproteinases activity studied in human endometrium as a paradigm of cyclic tissue breakdown and regeneration

When abundant and activated, matrix metalloproteinases (MMPs, or matrixins) degrade most, if not all, constituents of the extracellular matrix (ECM). The resulting massive tissue breakdown is best exemplified in humans by the menstrual lysis and shedding of the endometrium, the mucosa lining the uterus. After menstruation, MMP activity needs to be tightly controlled as the endometrium regenerates and differentiates to avoid abnormal tissue breakdown while allowing tissue repair and fine remodelling to accommodate implantation of a blastocyst. This paper reviews how MMPs are massively present and activated in the endometrium at menstruation, and how their activity is tightly controlled at other phases of the cycle. Progesterone represses expression of many but not all MMPs. Its withdrawal triggers focal expression of MMPs specifically in the areas undergoing lysis, an effect mediated by local cytokines such as interleukin-1α, LEFTY-2, tumour necrosis factor-α and others. MMP-3 is selectively expressed at that time and activates proMMP-9, otherwise present in latent form throughout the cycle. In addition, a large number of neutrophils loaded with MMPs are recruited at menstruation through induction of chemokines, such as interleukin-8. At the secretory phase, progesterone repression of MMPs is mediated by transforming growth factor-β. Tissue inhibitors of metalloproteinases (TIMPs) are abundant at all phases of the cycle to prevent any undue MMP activity, but are likely overwhelmed at menstruation. At other phases of the cycle, MMPs can elude TIMP inhibition as exemplified by recruitment of active MMP-7 to the plasma membrane of epithelial cells, allowing processing of membrane-associated growth factors needed for epithelial repair and proliferation. Finally, receptor-mediated endocytosis through low density lipoprotein receptor-related protein-1 (LRP-1) efficiently clears MMP-2 and -9 at the proliferative and secretory phases. This mechanism is probably essential to prevent any excessive ECM degradation by the active form of MMP-2 that is permanently present. However, shedding of the ectodomain of LRP-1 specifically at menstruation prevents endocytosis of MMPs allowing full degradation of the ECM. Thus endometrial MMPs are regulated at the levels of transcription, release from infiltrating neutrophils, activation, binding to the cell membrane, inhibition by TIMPs and endocytic clearance by LRP-1. This allows tight control during endometrial growth and differentiation but results in a burst of activity for menstrual tissue breakdown. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.

SAR150640, a selective beta3-adrenoceptor agonist, prevents human myometrial remodelling and activation of matrix metalloproteinase in an in vitro model of chorioamnionitis

BACKGROUND AND PURPOSE

The uterine pathophysiology underlying inflammatory conditions such as chorioamnionitis remains largely unclear. As we have shown that beta(3)-adrenoceptors act as regulators of myometrial inflammation, we wanted to investigate the potential role of beta(3)-adrenoceptors in preventing uterine remodelling induced by inflammation.

EXPERIMENTAL APPROACH

The consequences of human chorioamnionitis on myometrial remodelling were characterized by Sirius Red staining and metalloproteinase (MMP) expression, and compared with the effects of incubating human myometrial samples with Escherichia coli lipopolysaccharide (LPS) in vitro. We also assessed the effect of SAR150640, a selective beta(3)-adrenoceptor agonist, on the production and activity of MMPs.

KEY RESULTS

Chorioamnionitis was associated with a 46% decrease in total collagen, as well as over-expression of MMP2 (+61%) and MMP9 (+84%); both effects were reproduced by incubation with LPS (10 microg x mL(-1), 48 h). LPS-induced over-expression of MMP2 and MMP9 in normal human myometrium was paralleled by an overactivity of the proteins. Both over-expression and overactivity were prevented by the beta(3)-adrenoceptor agonist SAR150640 in a concentration-dependent manner. SAR150640, by itself, did not exhibit any effect on MMP production in control tissues.

CONCLUSIONS AND IMPLICATIONS

This study shows that inflammation was associated with an intense remodelling of human myometrium, a process likely to be explained by MMP activation. Our study emphasizes the potential therapeutic relevance of beta(3)-adrenoceptor agonists to the treatment of preterm labour and other uterine inflammatory conditions.

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.