Luigi Devoto

Mechanism of action of hormonal preparations used for emergency contraception: a review of the literature

This paper focuses on the research efforts undertaken to understand how emergency contraception (EC) methods act to prevent pregnancy and to identify what is known and what are the important gaps that need to be addressed. Divided into five sections the first section presents a discussion on the background of the review and a brief description of the mode of use efficacy and most common side effects of the Yuzpe regimen levonorgestrel (LNG) and mifepristone. Section 2 includes studies on the effects of postcoital steroid administration upon fertility in nonprimate animal models. Section 3 focuses on the effects of estrogens progestins or the antiprogestin mifepristone administered in the preovulatory period to macaques and the New World monkey Cebus apella. Section 4 highlights clinical studies on the effects of the Yuzpe regimen administered before and after the luteinizing hormone surge and on progesterone-regulated endometrial proteins. Finally section 5 identifies some of the most difficult areas of the literature that need to be researched.

Cholesterol transport and steroidogenesis by the corpus luteum

The synthesis of progesterone by the corpus luteum is essential for the establishment and maintenance of early pregnancy. Regulation of luteal steroidogenesis can be broken down into three major events; luteinization (i.e., conversion of an ovulatory follicle), luteal regression, and pregnancy induced luteal maintenance/rescue. While the factors that control these events and dictate the final steroid end products are widely varied among different species, the composition of the corpus luteum (luteinized thecal and granulosa cells) and the enzymes and proteins involved in the steroidogenic pathway are relatively similar among all species. The key factors involved in luteal steroidogenesis and several new exciting observations regarding regulation of luteal steroidogenic function are discussed in this review.

Control of human luteal steroidogenesis.

The human corpus luteum (CL) undergoes a dynamic cycle of differentiation, steroid hormone production and regression during the course of non-fertile cycles. In humans and other primates, luteal steroidogenesis is absolutely dependent on pituitary-derived LH. However, changes in LH and LH receptor expression do not explain the marked decline in progesterone production at the end of the luteal phase. Changes in the level of the steroidogenic acute regulatory protein (StAR), a gene whose expression is controlled by LH most likely account for the cyclic pattern of progesterone production. During the mid-to-late luteal phase of a fertile cycle, chorionic gonadotropin (hCG) rescues the CL, overcoming the actions of the factors inducing luteolysis. Although the agents causing regression of the CL in a non-fertile cycle are not yet known, intra-luteal growth factors and cytokines that modify the action of LH probably contribute to the reduction of StAR expression and the subsequent fall in progesterone production.

The human corpus luteum: life cycle and function in natural cycles.

OBJECTIVE To summarize recent advances in the understanding of the endocrine signaling pathways between the hypothalamus, pituitary, and human corpus luteum (CL); to examine the major paracrine and autocrine mechanisms and the key genes and proteins involved in CL development, function, and regression in natural cycles; to review the endocrine and molecular response of the midluteal phase CL to in vivo administration of human chorionic gonadotropin (hCG); and to describe the ultrasonographic and Doppler evaluation of the ovary and endometrium throughout the luteal phase. DESIGN Published data in the literature, including the basic and clinical research studies of the authors. SETTING University-affiliated hospital and research centers. PATIENT(S) None. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Clinical and molecular analysis of human CL function. RESULT(S) The endocrine function of the subpopulations of luteal cells is critical for the maintenance of CL function, including neovacularization and steroid hormones production. We consider the key genes and proteins that favor development of luteal structure and function throughout the menstrual cycle and in our model of hCG treatment resembling early pregnancy. CONCLUSION(S) These data indicate that the functional lifespan of the CL depends on paracrine and autocrine mechanisms. Therefore, the significance of the key genes and proteins that we analyze in lutein cells during CL development, function, demise, and rescue by hCG is likely to bring new therapeutic applications for the management of fertility defects and the control of fertility.

Effects of leptin, interleukin-1α, interleukin-6, and transforming growth factor-β on markers of trophoblast invasive phenotype

Phenotypic changes of integrin and metalloproteinase secretion of the invasive human cytotrophoblast are regulated by cytokines and growth factors, but how this occurs is not completely understood. We used 24h cytotrophoblast cultures from first trimester pregnancies to investigate the effects of leptin and cytokines on the expression of the α2, α5, and α6 integrin subunits and on the activity of metalloproteinase-2 (gelatinase A) and metalloproteinase-9 (gelatinase B). The α2 subunit was marginally upregulated by leptin and interleukin-1α (IL-1α). All compounds tested upregulated, in some degree, the α5 expression. The α6 integrin subunit was massively upregulated, by leptin, interleukins, and transforming growth factor-β. None of the factors tested affected metalloproteinase-2 activity, but the activity of metalloproteinase-9 was upregulated by leptin and IL-1α. In conclusion, leptin and IL-1α actively induce some of the changes that cytotrophoblasts undergo to achieve a more invasive phenotype. A novel role for leptin is proposed during early pregnancy: leptin might be an autocrine/paracrine regulator of cytotrophoblast invasiveness during implantation and placentation.

Clomiphene citrate and ovulation induction.

Clomiphene can be used to treat anovulation due to hypothalamus or pituitary gland dysfunction, and it normalizes the luteal phase in stimulated patients. It can be used to estimate ovarian follicle reserve, and may be predictive of ovulation in women aged >/=35 years or with failed IVF. Contraindications include risk of congenital anomalies, chronic liver disease and visual disorders. Clomiphene may impair fertility through its effects on cervical mucus and in causing various endometrial dysfunctions. However, if clomiphene is administered in 50 mg doses, side-effects are avoided and efficacy is similar to that of a 100 mg dose, although daily dosages of 200 mg/day over 5 days can induce ovulation in approximately 70% of treated patients. Gonadotrophin concentrations increase up to days 5-9 when follicles are selected, and clomiphene is effective in patients with polycystic ovary syndrome (PCOS). Fifty percent of normal patients conceive, a value perhaps biased by the antagonistic effects of clomiphene on cervical mucus in some women. Clomiphene is valuable for IVF, and is used by some clinics in combination with HMG or recombinant FSH. Resistance to clomiphene can develop, and human chorionic gonadotrophin may be needed to induce ovulation in clomiphene cycles. Corticosteroids and human menopausal gonadotrophin (HMG) can be combined with clomiphene for stimulation, its combination with HMG long having been a standard protocol in assisted reproduction. PCOS patients may become insulin resistant, a condition improved by the administration of metformin. Other adverse effects include multiple pregnancies, an increase in the rate of multiple births, ovarian hyperstimulation and unsubstantiated claims of ovarian cancer.

Promoter hypermethylation of BRCA1 correlates with absence of expression in hereditary breast cancer tumors.

Germline mutations in BRCA1 account for a low proportion of hereditary cases in diverse populations. Several efforts have been made to find new genes involved in the inheritance of breast cancer with no success until today. The participation of BRCA1 in the development of breast cancer has been proposed in several studies where hypermethylation of its promoter and a decrease in expression has been reported for sporadic cases and one study on familial cases. To explore the participation of BRCA1 in hereditary carcinogenesis through a different mechanism than the inheritance of germline mutations, we studied the methylation status of its promoter in breast tumors, from patients previously screened for BRCA1/BRCA2 germline mutations. We also determined the presence of the BRCA1 protein in these tumors and correlated both events with tumor grade, hormone receptors and ERBB2 presence. Promoter hypermethylation of the BRCA1 gene was detected in 51% of our biopsies, among which 67% did not express the respective protein. This result leads us to suggest that hypermethylation could be considered as an inactivating mechanism for BRCA1 expression, either as a first or second hit. Moreover, a number of biopsies with absence of expression on BRCA1 showed negative detection of estrogen and progesterone receptors, a similar phenotype to BRCA1 mutated breast tumors.

Multicenter clinical trial on the efficacy and acceptability of a single contraceptive implant of nomegestrol acetate, Uniplant

Uniplant, a single Silastic implant containing nomegestrol acetate, provides contraceptive efficacy for one year. Uniplant use for one year was studied in 1,803 healthy women of reproductive age, enrolled from 10 centers in 9 countries, after informed consent. Implants were placed subdermally either in the upper arm or in the gluteal region. Two-hundred-seventy-six subjects discontinued prior to completing one year of study. Cumulative discontinuation rate at 12 months was 15.72%. Medical reasons for discontinuation were principally menstrual-related. Fifteen pregnancies occurred during the one year study period, resulting in a 12-month net cumulative pregnancy rate of 0.94%. Approximately 56% of subjects using Uniplant had bleeding patterns similar to normal menstruation. Results from this study confirm that Uniplant is an efficient, well tolerated, 12-month contraceptive implant, with the advantage of easier insertion and removal of the single implant compared to other multiple implant methods.

Bioinformatic detection of E47, E2F1 and SREBP1 transcription factors as potential regulators of genes associated to acquisition of endometrial receptivity

BackgroundThe endometrium is a dynamic tissue whose changes are driven by the ovarian steroidal hormones. Its main function is to provide an adequate substrate for embryo implantation. Using microarray technology, several reports have provided the gene expression patterns of human endometrial tissue during the window of implantation. However it is required that biological connections be made across these genomic datasets to take full advantage of them. The objective of this work was to perform a research synthesis of available gene expression profiles related to acquisition of endometrial receptivity for embryo implantation, in order to gain insights into its molecular basis and regulation.MethodsGene expression datasets were intersected to determine a consensus endometrial receptivity transcript list (CERTL). For this cluster of genes we determined their functional annotations using available web-based databases. In addition, promoter sequences were analyzed to identify putative transcription factor binding sites using bioinformatics tools and determined over-represented features.ResultsWe found 40 up- and 21 down-regulated transcripts in the CERTL. Those more consistently increased were C4BPA, SPP1, APOD, CD55, CFD, CLDN4, DKK1, ID4, IL15 and MAP3K5 whereas the more consistently decreased were OLFM1, CCNB1, CRABP2, EDN3, FGFR1, MSX1 and MSX2. Functional annotation of CERTL showed it was enriched with transcripts related to the immune response, complement activation and cell cycle regulation. Promoter sequence analysis of genes revealed that DNA binding sites for E47, E2F1 and SREBP1 transcription factors were the most consistently over-represented and in both up- and down-regulated genes during the window of implantation.ConclusionsOur research synthesis allowed organizing and mining high throughput data to explore endometrial receptivity and focus future research efforts on specific genes and pathways. The discovery of possible new transcription factors orchestrating the CERTL opens new alternatives for understanding gene expression regulation in uterine function.

A single midcycle dose of levonorgestrel similar to emergency contraceptive does not alter the expression of the L-selectin ligand or molecular markers of endometrial receptivity.

OBJECTIVE To examine the effects of a single-dose of 1.5 mg of levonorgestrel (commonly used as emergency contraceptive) on endometrial receptivity biomarkers through the oral or vaginal route. DESIGN Prospective randomized single-blinded trial. SETTING Affiliated Hospital and University Research Center. PATIENT(S) Fertile normal women previously sterilized by tubal ligation. INTERVENTION(S) Levonorgestrel (1.5 mg) was administered on the day of LH surge either orally (n = 14) or vaginally (n = 13). MAIN OUTCOME MEASURE(S) Molecular assessment of endometrial progesterone receptors, L-selectin ligand, glicodelin-A and αvβ3 integrin by Immunohistochemistry and reverse transcriptase-polymerase chain reaction. RESULT(S) Plasma progesterone concentration and endometrial dating were not different. The pattern of progesterone receptors and glycodelin-A expression was not affected during the early and midsecretory phase. Some endometrial biopsies from the group in which levonorgetrel was orally administered showed areas of glandular atrophy and stromal decidualization. However, the expression of the progesterone receptor, L-selectin ligand, αvβ3 integrin, and glycodelin-A were not different between the groups. CONCLUSION(S) Levonorgestrel, given as emergency contraceptive on the day of LH surge, does not disrupt either ovulation or progesterone production by the corpus luteum. The contraceptive mechanism of levonorgestrel at the time of LH surge does not include changes in the progesterone receptors or the endometrial receptivity biomarkers.