Chlormadinone acetate suppresses prostaglandin biosynthesis in human endometrial explants

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.

Effects of different progestins on prostaglandin biosynthesis in human endometrial explants

OBJECTIVE

To compare the effects of chlormadinone acetate (CMA), dienogest (DNG) and drospirenone (DRSP) on prostaglandin biosynthesis in a human endometrial explants model.

STUDY DESIGN

Human endometrial explants obtained by aspiration curettage and human endometrial YHES cells were stimulated with interleukin-1β (IL-1β) and exposed to CMA, DNG, DRSP or dexamethasone (DEX; YHES cells). Cellular messenger RNA (mRNA) levels of cyclooxygenase-2 (COX-2) were analyzed by reverse-transcription quantitative real-time polymerase chain reaction. Concentrations of prostaglandin F_2α (PGF_2α) in culture supernatants were measured by enzyme-linked immunosorbent assay.

RESULTS

CMA exerted after IL-1β stimulation a stronger down-regulation of COX-2 mRNA compared to DNG and DRSP in human explants (-55% vs. -40% and 46%, respectively). The effect of CMA on COX-2 mRNA was significantly stronger (p=.025) than that of DNG. Moreover, the effect of CMA was independent from cycle phase or presence of endometriosis. In order to evaluate the impact of the investigated progestins on effector molecules, PGF_2α release was determined in supernatants. Again, CMA reduced the PGF_2α release significantly by an average of -60% (p<.01). In contrast, no significant reduction was found for DNG and DRSP. In YHES cells, only DEX but not the progestins under study exerted a significant down-regulating effect (-79%, p<.01) on COX-2 mRNA after IL-1β stimulation.

CONCLUSION

Among the tested progestins, CMA displayed the most consistent suppression of prostaglandin biosynthesis in human endometrial explants.

IMPLICATION

Among three tested progestins, chlormadinone acetate had the most consistent suppressive effect on prostaglandins in endometrial explants. These findings support clinical observations about the efficacy of chlormadinone acetate in dysmenorrhea treatment.

Effect of oral contraceptives containing estradiol and nomegestrol acetate or ethinyl-estradiol and chlormadinone acetate on primary dysmenorrhea

OBJECTIVE

To study the three cycles effect on primary dysmenorrhea of the monophasic 24/4 estradiol/nomegestrol acetate (E2/NOMAC) and of the 21/7 ethinyl-estradiol/chlormadinone acetate (EE/CMA) oral contraceptive. The tolerability and the effect of both preparations on metabolism and health-related quality of life were also evaluated.

DESIGN

Prospective observational cohort study.

SETTING

Tertiary gynecologic center for pelvic pain.

PATIENTS

Subjects with primary dysmenorrhea requiring an oral contraceptive, who spontaneously selected either E2/NOMAC (n = 20) or EE/CMA (n = 20).

MAIN OUTCOME MEASURES

Visual Analogue Scale (VAS) score for dysmenorrhea, Short Form-36 questionnaire for health-related quality of life, lipoproteins and days of menstrual bleeding (withdrawal bleeding during oral contraceptive).

RESULTS

Mean age and body mass index (BMI) were similar between the two groups. The final analysis was performed on 34 women, 15 in E2/NOMAC and 19 in EE/CMA group. Compliance with treatment was significantly higher with EE/CMA (100%) than E2/NOMAC (75%) (p = 0.02). Both treatments significantly (p < 0.0001) reduced VAS of primary dysmenorrhea, similarly (E2/NOMAC by a mean of 74.7%, EE/CMA by a mean of 78.4%; p = 0.973). Only E2/NOMAC significantly increased SF-36 score (p = 0.001), both in physical (p = 0.001) and mental domains (p = 0.004). The mean number of days of menstrual bleeding was significantly reduced in E2/NOMAC group (from 4.86 ± 1.20 d to 2.64 ± 1.59 d, p = 0.0005 versus baseline, p = 0.007 versus EE/CMA group). BMI did not vary in either group. E2/NOMAC did not change lipoproteins and apoproteins while EE/CMA increased total cholesterol (p = 0.0114), HDL-cholesterol (p = 0.0008), triglycerides (p = 0.002), apoprotein-A1 (Apo-A1; p = 0.0006) and apopoprotein-B (Apo-B; p = 0.008), decreasing LDL/HDL ratio (p = 0.024).

CONCLUSIONS

Both oral contraceptives reduced similarly primary dysmenorrhea, with E2/NOMAC also reducing withdrawal bleedings and being neutral on lipid metabolism.