Sex differences in the cerebroprotection by Nestorone intranasal delivery following stroke in mice.

Our previous studies showed that intranasal delivery of progesterone offers a good bioavailability and neuroprotective efficacy after experimental stroke. We have also demonstrated that progesterone receptors (PR) are essential for cerebroprotection by endogenous progesterone and by progesterone treatment. The identification of PR as a potential drug target for stroke therapy opens new therapeutic indications for selective synthetic progestins. Nestorone® (16-methylene-17α-acetoxy-19-nor-pregn-4-ene-3, 20-dione, also known as segesterone acetate) is a 19-norprogesterone derivative that more potently targets PR than progesterone. The objective of this study was to evaluate the cerebroprotective efficiency of intranasal administration of Nestorone after middle cerebral occlusion (MCAO) in mice. We show here that intranasal administration is a very efficient route to achieve a preferential delivery of Nestorone to the brain and confers a slow elimination and a sustained bioavailability. Furthermore, intranasal administration of Nestorone (at 0.08 mg/kg) improved the functional outcomes and decreased the ischemic lesion in male but not in female mice at 48 h post MCAO. Use of PRNesCre mice, selectively lacking expression of PR in neural cells, and their control PRloxP/loxP littermates showed that the cerebroprotective effects of Nestorone in male mice depended on neural PR as they were not observed in PRNesCre mice. Our findings show that intranasal delivery of Nestorone may be an efficient strategy to promote recovery after stroke in males and confirm the key role of PR in cerebroprotection. Furthermore, they point to sex differences in the response to Nestorone treatment and emphasize the necessity to include males and females in experimental studies.

Nestorone® , a 19nor-progesterone derivative boosts remyelination in an animal model of demyelination.

INTRODUCTION: We previously showed that Nestorone® (NES), a synthetic progestin structurally related to progesterone, stimulated remyelination of the corpus callosum in a Cuprizone (CUP) mouse model of demyelination in intact females by promoting replenishment with mature oligodendrocytes (OL) (Glia. 2015;63:104-117). Here, we further investigated the underlying mechanisms of this promyelinating effect. METHODS: We explored whether NES, applied subcutaneously through Alzet mini-osmotic pumps, regulates specific transcription factors involved in oligodendrocyte progenitor cell (OPC) proliferation and their differentiation into mature OL, using RT-qPCR and Western Blot analysis. RESULTS: Our present data show that in comparison to controls, a one-week treatment with NES, through Alzet mini-osmotic pumps, enhanced the production of three relevant transcription factor mRNAs encoding Olig2, Myt1, and Sox17. After 3 weeks, NES treatment reversed the effect of CUP on the levels of corresponding Olig2, Myt1, and Sox17 proteins. Moreover, in mice receiving NES + Estradiol (E2) co-treatment, levels of Olig2, Myt1, and Sox17 proteins did not change as compared to NES alone. CONCLUSION: NES alone or with E2 increased the levels of transcription factors, essential for myelin synthesis.

Beyond contraception and hormone replacement therapy: Advancing Nestorone to a neuroprotective drug in the clinic.

Neurological diseases such as ischemic stroke can be debilitating and have limited treatments available. The progestin Nestorone® (segesterone acetate) has been evaluated for use in birth control and hormone replacement therapy due to its potency and high affinity for the progesterone receptor. Interestingly, Nestorone also exerts neuroprotection in animals afflicted with various central nervous system diseases, including stroke, which implicates its potential for treating these maladies in clinical settings. In fact, a recent Brain Research paper by Tanaka and colleagues demonstrates Nestorone's ability to reduce infarct sizes and preclude functional impairments in rats subjected to ischemic stroke. This commentary highlights Nestorone's properties as a progestin, its neuroprotective capabilities in animal studies, and how the Tanaka team's findings and previous clinical trials contribute to Nestorone's translation into a therapeutic agent for stroke and other neurological diseases.

Efficacy of the selective progesterone receptor agonist Nestorone for chronic experimental autoimmune encephalomyelitis.

Progesterone plays a protective role in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS). Besides spinal cord neuropathology, MS patients present a dysfunctional hippocampus. In this work we studied the therapeutic effects of the progestin Nestorone in the brain of mice with chronic EAE. Nestorone decreased clinical grade and enhanced motor behavior. In addition, it increased cell proliferation and doublecortin positive neuroblasts in the hippocampus, increased GABAergic interneurons and attenuated the number of Iba1+ microglia/macrophages, events possibly linked to enhancement of neurogenesis. Therefore, Nestorone protected against hippocampus abnormalities and improved functional outcomes of EAE mice, suggesting its potential value for MS.

Progesterone and related progestins: potential new health benefits.

Progesterone is a steroid hormone that is essential for the regulation of reproductive function. The main physiological roles of this hormone have been widely described. Progesterone and progestins have been approved for a number of indications including the treatment of irregular and anovulatory menstrual cycles and, when combined with estrogen, for contraception, and the prevention of endometrial hyperplasia in postmenopausal hormonal replacement therapy (HRT) regimens. Lack of understanding between the differences in categories of the progestins as well as with the physiological hormone has resulted in considerable controversy surrounding the use of progestins for HRT regimens. Newer evidence suggests that there are distinct differences between the molecules and there is no progestin class effect, with regard to benefits or side-effects. In addition to its role in reproduction, progesterone regulates a number of biologically distinct processes in other tissues, particularly in the nervous system and the vessels. Recently, it has been shown in animal experiments that progesterone and the progestin Nestorone(®) have positive effects on neuroregeneration and repair of brain damage, as well as myelin repair. The potential benefits of natural progesterone and its related derivatives warrant further investigation. It is hoped that a better understanding of the mechanism of action of progesterone and selected progestins will help in defining better therapies for men and women.

Progesterone receptors: a key for neuroprotection in experimental stroke.

Progesterone receptors (PR) are expressed throughout the brain. However, their functional significance remains understudied. Here we report a novel role of PR as crucial mediators of neuroprotection using a model of transient middle cerebral artery occlusion and PR knockout mice. Six hours after ischemia, we observed a rapid increase in progesterone and 5α-dihydroprogesterone, the endogenous PR ligands, a process that may be a part of the natural neuroprotective mechanisms. PR deficiency, and even haploinsufficiency, increases the susceptibility of the brain to stroke damage. Within a time window of 24 h, PR-dependent signaling of endogenous brain progesterone limits the extent of tissue damage and the impairment of motor functions. Longer-term improvement requires additional treatment with exogenous progesterone and is also PR dependent. The potent and selective PR agonist Nestorone is also effective. In contrast to progesterone, levels of the neurosteroid allopregnanolone, which modulates γ-aminobutyric acid type A receptors, did not increase after stroke, but its administration protected both wild-type and PR-deficient mice against ischemic damage. These results show that 1) PR are linked to signaling pathways that influence susceptibility to stroke, and 2) PR are direct key targets for both endogenous neuroprotection and for therapeutic strategies after stroke, and they suggest a novel indication for synthetic progestins already validated for contraception. Although allopregnanolone may not be an endogenous neuroprotective agent, its administration protects the brain against ischemic damage by signaling mechanisms not involving PR. Collectively, our data clarify the relative roles of PR and allopregnanolone in neuroprotection after stroke.

Contraceptive vaginal rings releasing Nestorone and ethinylestradiol: a 1-year dose-finding trial.

In a multicenter 1-year trial of contraceptive vaginal rings (rings) involving 150 women, three dose combinations of the progestin Nestorone (NES) and ethinylestradiol (EE) were compared with respect to effectiveness, safety and acceptability. Mean in vitro drug release rates for the three doses were 150 and 15, 150 and 20 and 200 and 15 microg/day of NES and EE, respectively. Each ring remained in situ for 21 days, removed for 7 days and then reinserted for a total of 13 cycles of use. We studied ring performance with respect to pregnancy and other termination events, adverse events, the extent of ovulation inhibition, serum drug levels and bleeding control. We also assessed the rings' effects on the vagina using a standardized colposcopy procedure. Seventy-two percent of the women completed the 1-year (> or = 350 days) study. In studied cycles, luteal activity (progesterone > or = 10 nmol/L) was noted in 17%, 7% and 12% of subjects with monitored cycles at the 150/15, 150/20 and 200/15 doses, respectively (p = .34). Two pregnancies occurred, both in subjects using the 200/15 microg/day ring. Breakthrough bleeding during ring use averaged about 2 days/year and breakthrough bleeding and spotting averaged about 7 days/year. In the entire trial, only two women discontinued because of bleeding problems. Medical conditions, chiefly vaginal problems, personal reasons and device loss or repeated expulsion were the principal reasons given for study discontinuation. Vaginal and cervical colposcopy, conducted with standardized techniques and standardized interpretations, revealed no elevated event incidence attributable to ring use. Clinical performance and adverse event profiles indicate that each of these 1-year NES/EE rings, used on a 21-day-in and 7-day-out regimen, provided women effective, acceptable and safe long-acting contraception under their own control.

Two-year performance of a Nestorone-releasing contraceptive implant: a three-center study of 300 women.

A 2-year trial of a single Nestorone (NES) rod implant was conducted at three Latin American centers, each enrolling 100 women. We studied the safety, effectiveness and acceptability of this progestin-releasing contraceptive implant. Three pregnancies occurred, the last at 18 months of use. Because no pregnancies were expected in the first 18 months, the trial was halted. At that time, 224 women had completed at least 18 months of use, and 99 women had used the implant for more than 24 months. Few participants used adjunctive contraception between the time the study was halted and the time they had their implant removed. No additional pregnancies occurred before the removal of the last implant. The 2-year cumulative pregnancy rate was 1.7 per 100 with a Pearl index of 0.6 per 100 for the 2-year period. The 1-year and 2-year continuation rates were 80.5 and 66.7 per 100, respectively. Menstrual and medical disturbances were the principal reasons for discontinuation, followed by planned pregnancy. Headache and weight gain frequently led to discontinuation. The NES implant had little important effect on most clinical chemistry and lipid parameters. Over the study course, the mean change in hemoglobin was <1%. Slight modification of the design of this single 2-year implant, restoring features previously examined in clinical trials, is likely to improve its effectiveness. A single NES implant appears to provide acceptable contraception for women.

Nestorone: clinical applications for contraception and HRT.

The 19-nor derivatives of progesterone are referred to as "pure" progestational molecules as they bind almost exclusively to the progesterone receptor (PR) without interfering with receptors of other steroids. In this category is Nestorone, which has strong progestational activity and antiovulatory potency with no androgenic or estrogenic activity in vivo. These properties make it highly suitable for use in contraception and hormonal therapy (HT). Due to its high potency, very low doses of Nestorone may be delivered via long-term sustained-release delivery systems. Nestorone, 75 or 100 microg per day, released by vaginal ring has suppressed ovulation in women, with inhibition of follicular maturation. A vaginal ring releasing both 150 microg of Nestorone and 15 microg of ethinyl estradiol per day has effectively suppressed ovulation for 13 consecutive cycles. Nestorone has also been used effectively in a single implant for contraception in breastfeeding women and shows promise for use in transdermal systems as a contraceptive or for HT when combined with estrogen.

Recent developments in contraceptive implants at the Population Council.

Development of contraceptive implant methods, when based on established or on new synthetic chemical entities, is a decadal or multi-decadal process. The process often requires the cooperation of numerous investigators for laboratory work, for early Phase II trials, for dose-finding trials, and for Phase III clinical trials. The Phase III work also requires cooperation with a commercial manufacturer and potential distributor of the product. The Population Council has recently completed developmental work on two levonorgestrel-releasing implants, with filings to regulatory agencies that support extended use of Jadelle implants for 5 years and Norplant implants for 7 years. When the developmental process includes establishing the clinical properties of a molecule not yet approved by regulatory agencies, the minimum development time appears to be two decades. The status and rationale of studies of a new Nestorone-releasing, single implant developed by the Population Council for a period of use of 2 years are presented.

Vaginal epithelial surface appearances in women using vaginal rings for contraception.

Vaginal inspections using colposcopy before insertion of contraceptive vaginal rings and at 2-month intervals during ring use were conducted on 169 users of four different formulations. The rings studied released Nestorone alone (50, 75, 100 g daily over 6 months); ethinyl estradiol: Nestorone (30:100 and 15:150 g daily over 6 months); ethinylestradiol:norethindrone acetate (20:1000 and 15:1000 g daily over 4 months); and ethinyl estradiol:norethindrone acetate (20:1000 g daily over 12 months). A total of 88 altered or atypical conditions of the vaginal surface appearance were recorded in 507 inspections (17.4% of inspections). Many of these atypical appearances were quite subtle. The incidence was significantly higher (p <0.01) than in the single pretreatment examinations (11 in 158 inspections; 7.0%), but closely matched that of a "control group" of sexually active women who were the subject of an earlier study by the same investigators. In that study, the incidence was 18% (57 atypical conditions in 317 inspections). In all, 83% of atypical conditions identified in the vagina during ring use had disappeared by the next scheduled colposcopy despite continued ring use. Findings of potential significance were conservatively defined as all ulcerations, those abrasions and ecchymoses that were >0.5 cm in any direction, and fields of five or more petechiae. Findings fitting those criteria comprised 30% of atypical conditions in ring users, 33% in the control group, and 27% pretreatment. The corresponding incidence as a percentage of inspections were 5.3%, 6. 0%, and 2.5% in the ring users, control groups, and pretreatment groups, respectively. These differences were not statistically significant. The findings suggest that the vaginal rings included in the studies contributed little, if at all, to clinically significant lesions or to total lesion incidence. Further definition would require a larger and longer-term study with matched controls.

Endometrial effect of transdermal estradiol and progestin ST-1435 in postmenopausal women.

OBJECTIVE: To study the endometrial effect of the transdermal synthetic progestin ST-1435. DESIGN: Prospective. SETTING: City Maternity Hospital, Helsinki, Finland. PATIENTS: Eleven postmenopausal women used transdermal estradiol (E2) patches for 6 weeks immediately before a vaginal operation for prolapse. For the last 10 days, 1 mg of ST-1435 transdermally in a gel was combined to the treatment. MAIN OUTCOME MEASURES: Blood samples were taken to follow serum concentrations of E2, follicle-stimulating hormone, and ST-1435. Endometrial samples for histologic examination were collected during the operation to evaluate the effect of the progestin. RESULTS: Transdermal absorption of ST-1435 resulted in reasonably constant serum concentrations of ST-1435 in each subject. A progestin effect on the endometrium was seen in 9 of 10 samples obtained. One sample did not show any progestin effect in spite of adequate ST-1435 levels, but this patient's E2 concentrations were low. CONCLUSIONS: When the estrogen stimulation was adequate, the transdermal ST-1435 induced a progestin effect on the endometrium, i.e., it had an end-organ effect.

[Treatment of hirsutism with spironolactone and progestagen combination]. / Traitement de l'hirsutisme par l'association de spironolactone et d'un progestatif.

The antiandrogenic activity of spironolactone was used for treating hirsutism in 76 women, 29 of whom also had acne. Midcycle vaginal bleeding was observed in 21 patients under spironolactone 75 mg per day. This side-effect disappeared after a progestagen administered 10 days each month was added to the treatment. With this combination, spironolactone was well tolerated and effective in treating acne within the first months of administration, but in 61 percent of the patients at least 6 months were required to improve hirsutism.

[Treatment of early menopause. A report of 2 cases]. / Traitement de la ménopause précoce. A propos de deux observations.

Veralipride was given to two patients with early menopause ascertained by hormonal investigations. In both women (aged 33 and 30 years), an estradiol-progestogen combination given for hot flushes, disorders of character, and depression, had been unsuccessful. Symptoms resolved under therapy with veralipride alone or associated with the previous treatment. In one patient, symptoms recurred after veralipride was discontinued and resolved again once the drug was resumed.

[OEstradiol and progesterone steroid hormone receptors in cancer of the endometrium. The significance of the progesterone receptor (author's transl)]. / Les récepteurs hormonaux stéroïdiens de l'estradiol et de la progestérone dans les cancers de l'endomètre. Signification du récepteur de la progestérone.

It would seem that the satisfactory way for the clinician to orientate the treatment by hormones in cancers of the endometrium lies in the presence at the same time of oestrogen and progesterone receptors and in particular of the latter. This applies when treating cancers of the endometrium with hormones in a way that is directed by chemical determination of hormone susceptibility.

PIP: This study investigates the frequency of the presence of estrogen and progesterone receptors in the different anatomopathological types of endometrial cancer. The study has been conducted on cancerous tissues samples before and after hormonotherapy. From a clinical point of view it is very important to know that, at least apparently, the best results are obtained when both estrogen and progesterone receptors are present in the cancerous tissues.

Hormonal treatment of mammary carcinoma with Progynon-Depot and Depostat.

The results of combined treatment with 90 mg estradiol valerianate and 300 mg 17-alpha-hydroxy-19-norprogesterone-capronate (SH 834) (3 ml once a week i.m.) in 117 cases with disseminated or inoperable mammary carcinoma are reported. Objective remissions of 3 to 36 months were obtained in 48 patients. Soft tissue, lung and pleura metastases responded more favourably than bone metastases. Liver and brain metastases were unaffected.