Study of the mechanisms coupling tissue breakdown and regeneration during menstruation in a murine model of human endometrial xenografts

Menstruation is a remarkable physiological process that couples tissue degradation and regeneration. Although globally regulated by cyclic fluctuations of ovarian steroids concentration, endometrial remodeling is tightly controlled in space and time by molecular mechanisms that are only partially understood. Inappropriate control of uterine homeostasis and/or menstruation is associated with pathologies such as infertility, endometriosis and dysfunctional uterine bleeding. The aim of this work was to better understand these regulatory mechanisms by using a murine model of human endometrium xenograft mimicking menstruation. In a first study, we found that hypoxia is not required for the induction of menstrual breakdown and early tissue repair. In a second study, we measured changes in xenograft volume and showed that hormone withdrawal alone triggered epithelial cell proliferation and tissue repair but without increased volume of the graft.(BIFA - Sciences biomédicales et pharmaceutiques) -- UCL, 201

Induction of post-menstrual regeneration by ovarian steroid withdrawal in the functionalis of xenografted human endometrium

STUDY QUESTION: Does the endometrial functionalis have the potential to undergo self-renewal after menstruation and how is this process controlled by ovarian steroids? SUMMARY ANSWER: Endometrial xenografts subjected to withdrawal of estradiol and progesterone shrink but also show signs of proliferation and tissue repair; new estradiol supply prevents atrophy but is not sufficient to increase graft volume. WHAT IS KNOWN ALREADY: Menstruation, i.e. cyclic proteolysis of the extracellular matrix of endometrial functionalis, is induced by a fall in estrogen and progesterone concentration and is followed by tissue regeneration. However, there is debate about whether regenerating cells must originate from the basalis or from stem cells and whether new estrogen supply is required for the early repair concomitant with menstruation. STUDY DESIGN, SIZE, DURATION: Fragments from human endometrial functionalis (from 24 hysterectomy specimens) were xenografted in ovariectomized SCID mice and submitted to a 4-day estradiol and progesterone withdrawal (to mimic menstruation) followed by re-exposure to estradiol (to mimic the proliferative phase). We measured signs of proliferation and changes in graft volume. PARTICIPANTS/MATERIALS, SETTING, METHODS: Endometrium was collected from spontaneously cycling women. Cell proliferation was examined by immunolabeling Ki-67, cyclin D1 and phosphorylated-histone H3. Xenograft volume was measured by magnetic resonance imaging. Xenograft histomorphometry was performed to determine how the different tissue compartments contributed to volume change. MAIN RESULTS AND THE ROLE OF CHANCE: Hormone withdrawal induced a rapid decrease in graft volume mainly attributable to stroma condensation and breakdown, concomitant with an increase of proliferation markers. Reinsertion of estradiol pellets after induced menstruation blocked volume decrease and stimulated epithelial and stromal growth, but, surprisingly, did not induce graft enlargement. Reinsertion of both estradiol and progesterone pellets blocked apoptosis. LIMITATIONS, REASONS FOR CAUTION: Mechanisms of endometrial remodeling are different in women and mice and the contribution of circulating inflammatory cells in both species remains to be clarified. Moreover, during human menstruation, endometrial fragments resulting from tissue proteolysis can be expelled by the menstrual flow, unlike in this model. WIDER IMPLICATIONS OF THE FINDINGS: Menstruation is a multifocal event within the functionalis. This is the first evidence that endometrial fragments that are not shed after menstrual tissue breakdown can support endometrial regeneration. Endometriosis is commonly thought to result from the retrograde migration of menstrual fragments of the degraded functionalis into the peritoneal cavity. Our study supports their potential to regenerate as ectopic endometrium. STUDY FUNDING/COMPETING INTERESTS: This work was supported by the Fonds de la Recherche Scientifique Médicale, Concerted Research Actions, Communauté Française de Belgique, Région wallonne, Région bruxelloise and Loterie nationale. P.H. and B.F.J. are research associates of the Belgian Fonds de la Recherche Scientifique (F.R.S.-F.N.R.S.). E.M. is Associate Editor at Human Reproduction. There is no conflict of interest to declare

Hypoxia is not required for human endometrial breakdown or repair in a xenograft model of menstruation.

Menstrual endometrial breakdown induced by estradiol and progesterone withdrawal is regularly attributed to vasospasm of spiral arteries causing ischemia and hypoxia. We investigated whether hypoxia actually occurred in an in vivo model of menstruation. Three complementary approaches were used to look for signs of hypoxia in fragments of human functionalis xenografted to ovariectomized immunodeficient mice bearing pellets-releasing estradiol and progesterone, and then deprived of ovarian steroids. Hormone withdrawal 21 d after grafting induced menstrual breakdown and MMP expression within 4 d. Local partial oxygen pressure (pO2) was measured by electron paramagnetic resonance using implanted lithium phtalocyanine crystals. In mice with hormone maintenance until sacrifice, pO2 was low one week after grafting (14.8+/-3.4 mmHg) but increased twofold from the second week when tissue was largely revascularized. After 3 wk, pO2 was not modified by hormone withdrawal but was slightly increased on hormone reimpregnation 4 d after removal (34.7+/-6.1 mmHg) by comparison with hormone maintenance (27.1+/-8.6 mmHg). These results were confirmed using fluorescence quenching-based OxyLite measurements. In a further search for signs of hypoxia, we did not find significant HIF1-alpha immunostaining, nor pimonidazole adducts after hormone withdrawal. We conclude that hypoxia is not needed to trigger menstrual-like tissue breakdown or repair in human endometrial xenograft.-Coudyzer, P., Lemoine, P., Jordan, B. F., Gallez, B., Galant, C., Nisolle, M., Courtoy, P. J., Henriet, P., and Marbaix, E. Hypoxia is not required for human endometrial breakdown or repair in a xenograft model of menstruation

Prospective evaluation of ovarian function in women with breast cancer treated with anthracyclin-based chemotherapy with or without docetaxel

Abstract Background: to determine prospectively the incidence of chemotherapy-related amenorrhea and the recovery of ovarian function in premenopausal women with breast cancer undergoing adjuvant or neoadjuvant anthracyclin-based chemotherapy with or without docetaxel.Material and methods: we studied the incidence and the reversibility of clinical amenorrhea induced by different chemotherapy regimens: i) 6 cycles of 5-fluorouracil 500mg/m2, epirubicin 100mg/m2 and cyclophosphamide 500mg/m2 on day 1 every 3 weeks (6FEC) and ii) 3 cycles of FEC 100 followed by 3 cycles of docetaxel 100 mg/m2 on day 1 every 3 weeks (3FEC/3D) and iii) 4 cycles of FEC 100 followed by 4 cycles of docetaxel on day 1 every 3 weeks (4FEC100/4D) .Recovery of ovarian function was defined as recovery of premenopausal hormonal values :luteinizing hormone (LH &amp;lt;17mIU/ml),follicle-stimulating hormone (FSH &amp;lt;45.7mIU/Ml) and oestradiol (E2&amp;gt;50pg/ml).This recovery of ovarian function did not need to be associated with regular menses.Hormonal dosages were performed every 3 months starting at the beginning of chemotherapy and during the year following the end of chemotherapy.After, dosages were performed every 6 months.Results: 170 premenopausal patients were included between january 2005 and january 2008: 62 patients received 6FEC, 66 patients 3FEC/3D and 42 patients 4FEC/4D. The median age was 41 years (range: 25-51) in 6FEC, 42.8 years (range: 27-52.8) in 3FEC/3D and 40.2 years (range: 24-49.5)in 4FEC/4D. The incidence of chemotherapy-related amenorrhea at the end of chemotherapy was similar in the 3 groups: 90.3% in the 6FEC arm, 89.4% in the 3FEC/3D arm and 92.8% in the 4FEC/4D arm. However in the year following the end of chemotherapy, more patients recovered ovarian function in the 3FEC/3D arm (51.5%)(p=0.017) and in the 4FEC/4D arm (50%)(p=0.046)compared with the 6FEC group (30.6%). The difference was statisticaly significant for patients &amp;gt; or=40 years but not for patients &amp;lt; 40 years.Importantly, among the 23 patients with premenopausal hormonal values and treated with tamoxifen, 12/23 did not mention any menses recovery during the first year of follow-up.Conclusion: our prospective study confirms our previous retrospective data showing that 3FEC/3D and 4FEC/4D induce less definitive amenorrhea than 6FEC. Age is the most important predictor of ovarian function recovery, independently of chemotherapy regimen.Anamnestic data, especially in patients treated with tamoxifen are insufficient to determine pre-or postmenopausal status. Therefore, hormonal values must be followed regularly during and after chemotherapy. Since the menopausal status has an impact on the endocrine therapy choice. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2086.</jats:p