Effects of danazol, gonadotropin-releasing hormone agonist, and estrogen/progestogen combination on experimental endometriosis in the ovariectomized rat

Vaginal Wall Endometriosis Treated by Low-Dose Estrogen-Progestin: A Case Report

As vaginal wall endometriosis is rare, standard therapy has not yet been established. We report here a case of vaginal wall endometriosis that was reduced through administration of low-dose estrogen-progestin (LEP). The patient was a 37-year-old woman who presented with atypical genital bleeding (AGB) and dysmenorrhea. We recognized small hematomatous lesions on the posterior fornix of the vagina and a 3-cm mass in the pouch of Douglas, and we diagnosed the patient with vaginal wall endometriosis. We administered drug therapy with LEP. AGB stopped, and both the hematomatous vaginal wall lesion and the mass in the pouch of Douglas were reduced in size. The vaginal and pouch of Douglas lesions did not grow, and both AGB and dysmenorrhea did not appear for 42 months. LEP reduces vaginal wall endometriosis and rectovaginal endometriosis. In this case, we confirmed the direct effect of LEP on a vaginal wall endometriosis lesion. LEP therapy may be effective as postoperative therapy for vaginal wall endometriosis.

An overview of the current status of clinical trials on endometriosis: issues and concerns

OBJECTIVE

To examine and compare differences, if any, between industry- and nonindustry-sponsored clinical trials on endometriosis and to evaluate the effect of prior published positive preclinical results, or lack thereof, on trial status.

DESIGN

Cross-sectional study of clinical trials on endometriosis that evaluate drugs/biologicals registered at ClinicalTrials.gov as of July 3, 2013.

SETTING

University-affiliated hospital.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Trial status, size, phase, and duration; use of comparator groups; drug classes, number of arms, targeting conditions; and presence or absence of prior positive preclinical results before the launch of the trial.

RESULT(S)

Eighty trials were identified. The trials sponsored by industry and non-industry have distinct features, differing in trial status, phase, comparator, drug classes, number of arms, trial size, and duration. The phase II/III trials are predominantly industry supported, but these trials frequently use placebo as the comparator. Trials launched without prior published preclinical results do not seem to fare well, although the presence of such studies is no guarantee for success.

CONCLUSION(S)

Questions as to whether the drug on trial is truly superior to the best available drug or of its cost-benefit profile are overlooked in most cases. There seems to be a deluge of "me-too" drugs with equivocal superiority over existing drugs and cost-benefit profiles. Because clinical trials are time-consuming, no blockbuster drug for endometriosis seems to be on the horizon yet.

Individual and combined effects of triptoreline and gestrinone on experimental endometriosis in rats

OBJECTIVES

To evaluate the effects of triptoreline, gestrinone, and both, on experimental endometriosis in rats.

STUDY DESIGN

Experimental endometriosis was surgically induced in 225 Wistar rats. Of these, 202 rats showed at least one grown implant, 22 of which composed the control group, while 180 were treated with triptoreline, gestrinone, or both, for 28 days. The implants were evaluated again after 25 days.

RESULTS

There were no changes in size in the control group. About 73% of the implants treated with triptoreline showed a high reduction (> 50%), vs. 51% with gestrinone (P < 0.0005) and 65% with both (P < 0.005). Triptoreline caused macroscopic resolution in 40% of the implants vs. 31% for gestrinone (not significant) and 26% for both substances (P < 0.05). In the triptoreline group, the mean size of the implants decreased by 65% between the 25th and 28th days, 58% between the 29th and the 35th, and 39% after the 36th day. This reduction was 51%, 36%, and 33%, respectively, in gestrinone group.

CONCLUSIONS

Triptoreline was more effective than gestrinone, but perhaps not in the long run. Their association did not improve the results.

Induction of endometriosis in mice: a new model sensitive to estrogen

Endometriosis consists of the growth of endometrial tissue outside the uterus. A rat model of endometriosis is available to evaluate the potential for environmental chemicals to promote the disease but may be relatively insensitive for the evaluation of the hazard of certain compounds. Our objective, which was to develop a mouse model for endometriosis, was based on (a) the promotion of endometriosis in primates by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), (b) the apparent relationship between endometriosis and immunodeficiency, and (c) evidence that humoral immunity is suppressed in mice but not rats following TCDD exposure. In the mouse model, slices of uterus were sutured to intestinal mesenteric vessels. By 3 weeks after surgery, these sites were cyst-like structures. The growth of the sites was hormone dependent. In intact mice, sites measured 3.60 +/- 0.22 mm; vehicle and estrone (0.5 microgram/day) treatments produced site diameters of 0.95 +/- 0.128 and 5.28 +/- 0.355 mm, respectively. This new mouse model provides a sensitive and useful technique for future studies of the potential for specific xenobiotics to promote the development of endometriosis.

Effects of danazol and medroxyprogesterone acetate on estrogen-(estradiol and estriol) specific binding sites in rabbit uterus

In rabbit uterus, the presence of separate specific binding sites for not only estradiol but also estriol has been proposed. These sites may be correlated with an antiestradiol effect. Therefore, this study was designed to investigate the effect of antiestrogenic agents such as danazol and medroxyprogesterone acetate (MPA), especially on the estriol binding sites. Danazol and MPA in combination with estradiol were administered subcutaneously to immature female rabbits daily for 10 days, and resulted in a significant (p < 0.05) decrease in uterine weight and estradiol binding sites in the uterus. Treatment with MPA significantly (p < 0.05) decreased the level of estriol binding sites, but treatment with danazol resulted in this to a minimal extent in the uterus primed by estradiol. MPA did not bind to estradiol and estriol binding sites, while danazol at a high concentration bound to estriol binding sites with some affinity, but not to estradiol binding sites in the uterine cytosol of estrogen-primed rabbits. These results suggest that within the antiproliferative effect of danazol and MPA (an antiestrogenic action on estrogen-stimulated uterine growth) there are likely to be specific differences between some of the possible mechanisms of danazol and MPA in their action at the estriol binding site.

Progesterone receptor induction by danazol in cultured cancer cells and the rat uterus

We have previously reported that clinical trials relating to the use of danazol in the management of benign breast disease show a positive correlation between favourable clinical response and an induction of progesterone receptors in the affected tissue which is maintained for a period of at least 6 months subsequent to the cessation of treatment. Further studies designed at elucidating more clearly the actions of danazol at the cellular and molecular levels have confirmed that progesterone receptors are down-regulated by short-term progestin action at the level of the mRNA transcript, but that danazol is subsequently able to produce an enhanced cellular response, inducing progesterone receptors in the presence of oestrogenic agents. Uteri from danazol-treated rats showed a doubling of progesterone receptor concentrations compared with the control uteri. In the mammary cancer cell line T-47D, cells treated with danazol had increased progesterone receptor concentrations of 558.4 +/- 32.0 compared with 152.6 +/- 7.0 fmol/mg protein in the control cells. In both cases, these inductions were observed following a period of progesterone receptor suppression. Short-term molecular studies on T-47D cells indicated that progesterone and danazol initially inhibit mRNA transcription, but that 24 h after treatment an induction is observed. This is especially marked in the danazol-treated cells.

Treatment of estrogen-dependent gynecological disorders with the gonadotropin releasing hormone agonist buserelin

The authors examined the effect and tolerability of buserelin in 40 women with endometriosis and ten women with uterine leiomyoma. Buserelin was given intranasally, 200 micrograms three times a day for 6 months. Laparoscopy was performed before and after, and ultrasonography during the treatment. Hormone and lipid profiles and other biochemical tests were run during the treatment. The bone mineral density was tested by dual photon absorptiometry before and after therapy in a group of patients. Although most of the patients complained of hot flushes, no women dropped out. AFS mean pelvic score decreased from 24.10 to 6.95 and the size of the fibroids decreased by 69% at the end of 6 months of treatment. In conclusion, our data suggest that the use of GnRH agonist has a place in the treatment of endometriosis and uterine leiomyoma but further studies are needed to conclude that buserelin given intranasally at a dose of 600 micrograms/day for 6 months is an alternative to other conventional medical treatment modalities in terms of pregnancy and recurrence rates.

Tissue factors influencing growth and maintenance of endometriosis

The unpredictable response of endometriosis to steroids and its recurrence after therapy, led us to hypothesize a possible further control of this pathology by factors other than steroids. The presence of estrogen, progesterone and epidermal growth factor receptors (ER, PR, EGFr) was evaluated using immunohistochemistry before and after therapy with Danazol or a gonadotropin-releasing hormone analogue (GnRHa), Buserelin. EGFr, ER and PR were present in 100% of endometrial specimens, and in 71%, 29% and 49% of endometriotic implants, respectively. Danazol and GnRHa reduced immunohistochemical staining for EGFr antisera in the endometrial and endometriotic specimens. About 21% of endometriosis were EGFr positive and ER negative, suggesting a potential role of epidermal growth factor in growth and maintenance of endometrial ectopia.

Time-related effects of gonadotropin-releasing hormone analog treatment in experimentally induced endometriosis in the rat

The purpose of our study was to characterize the time-dependent effect of gonadotropin-releasing hormone analog (GnRH-a) therapy on endometriosis explant using the rat model. Endometriosis was induced in 60 mature female rats. One group of treated animals as well as controls were killed at 2, 4, 6 and 8 weeks of treatment at which time the explant was evaluated. Explant volume was significantly reduced in all treatment groups, an effect that was more significant in animals treated for greater than or equal to 4 weeks compared with those treated for only 2 weeks. We conclude that GnRH-a treatment caused gradual regression of endometrial explant that was effectively complete by 4 weeks of treatment. We further conclude that this experimental model may be useful in the evaluation of other modes of endometriosis therapy.

Ovarian suppression induced with Buserelin or danazol in the management of endometriosis: a randomized, comparative study

The effectiveness of Buserelin (Hoechst-Roussel Pharmaceuticals, Inc., Somerville, NJ) (0.2 mg subcutaneously [SC] or 1.2 mg intranasally [IN] per day) and danazol (800 mg per day) in inducing ovarian suppression for the management of endometriosis was compared in a prospective randomized study. During 6 months of treatment, peripheral follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol concentrations were suppressed to a similar degree in both groups. Symptomatic improvement and laparoscopically assessed regression of endometriotic lesions also were comparable. After treatment, 8 of 18 infertile women treated with Buserelin and 5 of 8 treated with danazol conceived. General and hypoestrogenic side effects were similar in both groups, while androgenic and anabolic were more frequent with danazol. High density lipoprotein (HDL)-cholesterol increased in the Buserelin and decreased in the danazol group. The study indicates that at the dose tested, buserelin and danazol induce a similar degree of ovarian suppression resulting in a comparable clinical improvement and regression of endometriotic lesions.

A randomized, prospective comparison of endocrine changes induced with intranasal leuprolide or danazol for treatment of endometriosis

A prospective, randomized trial compared hormonal changes induced with intranasal leuprolide 1.6 mg/day to danazol 800 mg/day for treatment of endometriosis. Both regimens induced anovulation and ovarian suppression in all subjects. Mean estradiol (E2) and progesterone (P) levels were suppressed with both regimens, but were lower with leuprolide. There was no difference in cumulative follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, although at times during treatment mean levels of these hormones were lower with leuprolide. Higher P levels in the danazol group, most likely of adrenal origin, indicated a suppressive effect on adrenal steroidogenesis. Symptomatic improvement was significant in both groups. Laparoscopy after treatment also demonstrated a decrease in endometriosis scores in both groups. At 12 months after treatment, cumulative pregnancy and live birth rates were similar in both groups. Leuprolide offers an attractive alternative to danazol for the medical treatment of endometriosis.