Endometriosis results from implantation of endometrial tissue outside the uterine cavity. Endometriosis might remain asymptomatic and discovered accidentally. However, it may cause symptoms, which include chronic pelvic pain, bleeding, infertility, and increases susceptibility to development of adenocarcinoma. The most prevailing hypothesis is that endometriosis results from implantation of endometrial tissue that gains access to peritoneal cavity by retrograde flow during menstruation. The factors contributing to the establishment and persistence of the endometriotic lesions (plaques) most probably include abnormalities of the genital tract, genetic predisposition, hormonal imbalance, altered immune surveillance, inflammatory response and abnormal regulation of the endometrial cells. The mediators that contribute to survival and progression of endometriosis are likely involved in the development of the symptoms of this process. Genomic studies have started to delineate the wide array of mediators involved and the complex genetic background required in the development of endometriosis. This review summarizes our current knowledge regarding the pathogenesis of endometriosis, including progress made with transgenic animals, and a clinical perspective on the diagnosis and management of this common process.
Progesterone-treated lymphocytes (generator lymphocytes) of healthy pregnant women release a nondialyzable factor that inhibits both cytotoxic activity and prostaglandin F2 alpha synthesis of test lymphocytes. Production of this factor is blocked by protein synthesis inhibitors (cycloheximide and actinomycin D). Sodium dodecylsulfate polyacrylamide electrophoresis of the partially purified material revealed a main 34,000 MW protein band. Progesterone-treated lymphocytes of pregnant women showing clinical symptoms of threatened preterm delivery (risk group) failed to release this substance.
Approximately, 10–15% of women of reproductive age are affected by endometriosis, which often leads to infertility. Endometriosis often has an inherited component, and several causative predisposing factors are hypothesized to underlie the pathogenesis of endometriosis. One working hypothesis is the theory of retrograde menstruation. According to the theory of retrograde menstruation, components of refluxed blood, including apoptotic endometrial tissue, desquamated menstrual cells, lysed erythrocytes, and released iron, induce inflammation in the peritoneal cavity. This in turn activates macrophage release of reactive oxygen species (ROS), leading to oxidative stress via the respiratory burst. Refluxed blood promotes the Fenton reaction, terminating in the production of hydroxyl radical, the most potently destructive ROS. In this article, we review the papers that demonstrate decreased quantity and quality of oocytes and embryos retrieved from IVF/ICSI patients with endometriosis. We discuss literature data demonstrating that ROS are generated in endometriotic tissues that have physical proximity to gametes and embryos, and demonstrating adverse impacts on oocyte, sperm and embryo microtubule apparatus, chromosomes, and DNA. Data that addresses the notions that endometriosis causes oocyte and fetal aneuploidy and that these events are mediated by ROS species are also discussed. Literature data are also discussed that employ use of anti-oxidant molecules to evaluate the importance of ROS-mediated oxidative damage in the pathogenesis of endometriosis. Studies are discussed that have employed anti-oxidants compounds as therapeutics to improve oocyte and embryo quality in infertile subjects, and improve fertility in patients with endometriosis.
We measured the noradrenaline (NA), serotonin (5-HT) and dopamine (DA) contents of 47 normally maturated and 16 cystically degenerated follicular fluid samples obtained from patients involved in the in vitro fertilization and gamete transfer program. The patients were given human menopausal gonadotropin (HMG), as a superovulation treatment, and 7,500 IU human chorionic gonadotropin (HCG) to induce ovulation 34–36 h prior to the follicular puncture done by laparoscope. The NA content of the normally developed follicles was 11.4 + 8.4 µg/l00 ml on average. For cystically degenerated follicles, the following data were obtained: 1.1 + 0.7 µg/l00 ml (p < 0.001). 5-HT and DA contents in the preovulatory follicles are 14.3 ± 8.9 and 19.3 ± 8.2 µg/l00 ml, respectively; at the same time, 5-HT and DA contents in the cystically degenerated follicles were 12.2 ± 6.2 and 12.7 ± 6.8µg/l00ml, respectively. They suggest that the higher amount of NA in the follicular fluid might play an important role in the mechanism of ovulation, the regulation of postovulatory tubal motility and the release of progesterone from granulosa cells.
According to some estimates, at least 70% of feedstuffs and finished feeds are contaminated with one or more mycotoxins and, due to its significant prevalence, both animals and humans are highly likely to be exposed to these toxins. In addition to health risks, they also cause economic issues. From a healthcare point of view, zearalenone (ZEA) and its derivatives have been shown to exert many negative effects. Specifically, ZEA has hepatotoxicity, immunotoxicity, genotoxicity, carcinogenicity, intestinal toxicity, reproductive toxicity and endocrine disruption effects. Of these effects, male reproductive deterioration and processes that lead to this have been reviewed in this study. Papers are reviewed that demonstrate estrogenic effects of ZEA due to its analogy to estradiol and how these effects may influence male reproductive cells such as spermatozoa, Sertoli cells and Leydig cells. Data that employ epigenetic effects of ZEA are also discussed. We discuss literature data demonstrating that reactive oxygen species formation in ZEA-exposed cells plays a crucial role in diminished spermatogenesis; reduced sperm motility, viability and mitochondrial membrane potential; altered intracellular antioxidant enzyme activities; and increased rates of apoptosis and DNA fragmentation; thereby resulting in reduced pregnancy.
The aim of this study was to explore the direct action of melatonin (Me) on basal and gonadotropin-stimulated progesterone (PG) and estradiol (E2) secretion of human granulosa cells (GCs) cultured in serum-free medium and in a superfused GC system. Human GCs were isolated from preovulatory follicular fluid aspirated from 34 women undergoing in vitro fertilization at the University Women’s Hospital of Tübingen. PG and E2 production was measured in the presence and absence of Me, propranolol, LH or FSH using radioimmunoassay. Statistical analysis of the data was performed by ANOVA and Newman-Keuls test. Me stimulated E2 secretion in a dose-dependent manner. Propranolol did not cause any change in E2 secretion, and when given with Me, it only partially blocked but could not entirely prevent E2 output. There was no statistically significant effect of Me on PG production when Me was administered at concentrations between 10–4 and 10–8 M. However, at 10–3 M Me significantly suppressed PG output of granulosa cells. LH and FSH significantly stimulated the secretion of both steroid hormones. Me significantly reduced LH- and FSH-induced E2 secretion, as well as LH-stimulated PG output, while it caused only a slight, yet significant decrease in PG secretion. In the superfused GC system, FSH and LH resulted in a significant stimulatory effect on PG release. Me did not modify the stimulatory effect of FSH on PG, while it caused some delay in LH-stimulated PG release. Propranolol and Me had no stimulatory effect on PG release. On the basis of our results we suggest that Me has a direct modulatory effect on basal E2 and gonadotropin-stimulated E2 and PG secretion of human GCs. The observed effect may play a physiological role in the regulation of GC function during the menstrual cycle.
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