Reactive oxygen species controls endometriosis progression

Surgery Versus Pharmacological Treatment for Endometriosis

The two major consequences of endometriosis are pain and infertility. Despite numerous studies and proposed guidelines, some aspects of the treatment for these complications are still under debate or lack convincing evidence that favors one approach over the other. Future studies will hopefully present new evidence in regard to the optimal treatment for each indication and suggest innovative pharmacotherapy following improved understanding of the pathophysiology of endometriosis. Until then, individualization of the treatment according to the specific indication, taking into consideration the benefits versus the risks for the patient and the tolerability profile, remains the most appropriate approach.

Hormonal therapy deregulates prostaglandin-endoperoxidase synthase 2 (PTGS2) expression in endometriotic tissues

CONTEXT

Endometriosis is a common gynecologic condition characterized by an important inflammatory process mediated by the prostaglandin pathway. Oral contraceptives are the treatment of choice for symptomatic endometriotic women. However the effects of oral contraceptives use and prostaglandin pathway in endometriotic women are actually still unknown.

OBJECTIVE

To investigate the expression of prostaglandin pathway key genes in endometriotic tissue, affected or not by hormonal therapy, as compared with healthy endometrial tissue.

DESIGN

This was a comparative laboratory study.

SETTING

This study was conducted in a tertiary-care university hospital.

PATIENTS

Seventy-six women, with (n = 46) and without (n = 30) histologically proven endometriosis.

MAIN OUTCOME MEASURES

Prostaglandin-endoperoxidase synthase (PTGS)1, PTGS2, prostaglandin E receptor (PTGER)1, PTGER2, PTGER3, and PTGER4 mRNA levels in endometrium of disease-free women and in eutopic and ectopic endometrium of endometriosis-affected women. PTGS2 expression was further investigated by immunohistochemistry, using specific monoclonal antibodies. PTGS2 expression was analyzed at mRNA and protein levels and correlated with taking hormonal treatment.

RESULTS

PTGS2 expression was significantly increased in eutopic and ectopic endometrium as compared with healthy tissue (induction of 9.6- and 6.3-fold, respectively; P = .001). PTGS2 immunoreactivity increased gradually from normal endometrium to eutopic and ectopic endometrium (h-score of 96.7 ± 55.0, 128.3 ± 66.1, and 226.7 ± 62.6, respectively, P < .001). PTGER2, PTGER3, and PTGER4 expression increased significantly and gradually from normal to eutopic and ectopic endometrium, whereas PTGER1 remained unchanged. Patients under hormonal treatment had a higher PTGS2 expression at transcriptional and protein levels as compared with those without treatment (P = .002 and P = .025, respectively).

CONCLUSIONS

Prostaglandin pathway is strongly deregulated in eutopic and ectopic endometrium of women suffering from endometriosis for the benefit of an increased PTGS2 expression. We show for the first time that hormonal treatment appears to enhance even more PTGS2 expression. These results contribute to explain why medical treatment could fail to control endometriosis progression.

Increased oxidation-related glutathionylation and carbonic anhydrase activity in endometriosis

This study examined the possible involvement of carbonic anhydrase activation in response to an endometriosis-related increase in oxidative stress. Peripheral blood samples obtained from 27 healthy controls and 30 endometriosis patients, classified as having endometriosis by histological examination of surgical specimens, were analysed by multiple immunoassay and carbonic anhydrase activity assay. Red blood cells (RBC) were analysed for glutathionylated protein (GSSP) content in the membrane, total glutathione (GSH) in the cytosol and carbonic anhydrase concentration and activity. In association with a membrane increase of GSSP and a cytosolic decrease of GSH content in endometriosis patients, carbonic anhydrase significantly increased (P < 0.0001) both monomerization and activity compared with controls. This oxidation-induced activation of carbonic anhydrase was positively and significantly correlated with the GSH content of RBC (r = 0.9735, P < 0.001) and with the amount of the 30-kDa monomer of carbonic anhydrase (r = 0.9750, P < 0.001). Because carbonic anhydrase activation is implied in many physiological and biochemical processes linked to pathologies such as glaucoma, hypertension, obesity and infections, carbonic anhydrase activity should be closely monitored in endometriosis. These data open promising working perspectives for diagnosis and treatment of endometriosis and hopefully of other oxidative stress-related diseases. Endometriosis is a chronic disease associated with infertility and local inflammatory response, which is thought to spread rapidly throughout the body as a systemic subclinical inflammation. One of the causes in the pathogenesis/evolution of endometriosis is oxidative stress, which occurs when reactive oxygen species are produced faster than the endogenous antioxidant defence systems can neutralize them. Once produced, reactive oxygen species can alter the morphological and functional properties of endothelial cells, including permeability and adhesion molecule expression, thus contributing to ongoing inflammation. Due to their main cellular functions--delivery of O2 from lung to tissue and removal of CO2 from tissue to lung--red blood cells (RBC) are exposed to oxidative stress. Carbon dioxide in tissue capillaries diffuses into red cells, where it is rapidly hydrated by the action of cytosolic carbonic anhydrase. Analysis of the oxidation status of endometriotic RBC membranes showed a high content of glutathionylated proteins, indicating pre-existing oxidation-related alterations. The increase in glutathionylated proteins was correlated to increased carbonic anhydrase activity in endometriotic RBC compared with healthy controls. Carbonic anhydrase is a family of metalloenzymes involved in many physiological processes such as acid-base homeostasis, respiration, carbon dioxide and ion transport, and bone resorption, and in the regulation of ureagenesis, gluconeogenesis, lipogenesis and tumourigenesis. Due to the potential implication of carbonic anhydrase activation in many pathologies, such as glaucoma, hypertension, obesity and infections, carbonic anhydrase activity should be closely monitored in endometriosis to prevent possible complications and/or worsening of related conditions.

The distinguishing cellular and molecular features of the endometriotic ovarian cyst: from pathophysiology to the potential endometrioma-mediated damage to the ovary

BACKGROUND

Clinical data suggest that the presence of an ovarian endometrioma may cause per se damage to the surrounding otherwise healthy ovarian tissue. However, the basic research has so far done a limited job in trying to understand the potential detrimental effect of an endometrioma presence in the context of the ovarian physiology. We have reviewed the literature with the aim of characterizing the pathophysiology of the endometrioma focusing mostly on factors and mechanisms potentially affecting the surrounding, otherwise normal, ovarian tissue.

METHODS

Comprehensive searches of PUBMED were conducted to identify human studies published from 1991 to 2013 in the English language on the cellular and molecular characterization of the various endometrioma components.

RESULTS

An endometrioma contains free iron, reactive oxygen species (ROS), proteolytic enzymes and inflammatory molecules in concentrations from tens to hundreds of times higher than those present in peripheral blood or in other types of benign cysts. The cyst fluid causes substantial changes in the endometriotic cells that it baths from gene expression modifications to genetic mutations The physical barrier between the cyst contents and the normal ovarian tissue is a thin wall composed of the ovarian cortex itself or fibroreactive tissue. ROS potentially permeating the surrounding tissues and proteolytic substances degrading the adjacent areas are likely to cause the substitution of normal ovarian cortical tissue with fibrous tissue in which the cortex-specific stroma is reduced. The fibrosis is associated with smooth muscle metaplasia and followed by follicular loss and intraovarian vascular injury. Follicular density in tissue surrounding the endometriotic cyst was consistently shown to be significantly lower than in healthy ovaries but this pathological change does not appear to be caused by the stretching of surrounding tissues owing to the presence of a cyst.

CONCLUSIONS

There is sufficient molecular, histological and morphological evidence, in part deriving from knowledge of the pathophysiology, to support a deleterious effect of the endometrioma on the adjacent ovarian cortical tissue, independent of the mere mechanical stretching owing to its size.

Increased serum oxidative stress markers in women with uterine leiomyoma

Background

Uterine leiomyomas (fibroids) are the most common gynaecological benign tumors in premenopausal women. Evidences support the role of oxidative stress in the development of uterine leiomyoma. We have analysed oxidative stress markers (thiols, advanced oxidized protein products (AOPP), protein carbonyls and nitrates/nitrites) in preoperative sera from women with histologically proven uterine leiomyoma.

Methodology/Principal Findings

We conducted a laboratory study in a tertiary-care university hospital. Fifty-nine women with histologically proven uterine leiomyoma and ninety-two leiomyoma-free control women have been enrolled in this study. Complete surgical exploration of the abdominopelvic cavity was performed in each patient. Preoperative serum samples were obtained from all study participants to assay serum thiols, AOPP, protein carbonyls and nitrates/nitrites.

Concentrations of serum protein carbonyl groups and AOPP were higher in leiomyoma patients than in the control group (p=0.005 and p<0.001, respectively). By contrast, serum thiol levels were lower in leiomyoma patients (p<0.001). We found positive correlations between serum AOPP concentrations and total fibroids weight (r=0.339; p=0.028), serum AOPP and serum protein carbonyls with duration of infertility (r=0.762; p=0.006 and r=0.683; p=0.021, respectively).

Conclusions/Significance

This study, for the first time, reveals a significant increase of protein oxidative stress status and reduced antioxidant capacity in sera from women with uterine leiomyoma.

17β-Estradiol and steady-state concentrations of H2O2: antiapoptotic effect in endometrial cells from patients with endometriosis

Increased levels of hydrogen peroxide (H2O2) can initiate protective responses to limit or repair oxidative damage. However, H2O2 signals also fine-tune responses to growth factors and cytokines controlling cell division, differentiation, and proliferation. Because 17β-estradiol (E2) also plays important roles in these processes, and is considered a major risk factor in the development and progression of endometriosis, this study evaluated whether E2 has an antiapoptotic effect on oxidative stress in endometrial cells in combination with steady-state H2O2 levels ([H2O2]ss). Endometrial stromal cells were prepared from the eutopic endometrium of 18 women with and without endometriosis to produce primary cells. These cells were stimulated with E2 for 20h, exposed to [H2O2]ss, and examined for cell viability, proliferation, and apoptosis. The endometrial cells from women with endometriosis maintained the steady state for 120min at high H2O2 concentrations. When they were pretreated with E2 and exposed to [H2O2]ss, a decrease in apoptosis level was observed compared to the control cells (p<0.01). The endometrial cells from patients with endometriosis subjected to both E2 and [H2O2]ss showed increased ERK phosphorylation. These findings suggested that H2O2 is a signaling molecule that downregulates apoptosis in endometrial cells, supporting the fact that endometriosis, albeit a benign disease, shares some features with cancer such as decreased catalase levels. These results link the E2 effects on [H2O2]ss to resistance to apoptosis and progression of endometriosis.

Mitochondrial NADH:ubiquinone oxidoreductase alterations are associated with endometriosis

Genetic alterations and aberrant expression of 'mitochondrial membrane complex I' (MMC-I) underlie several complex human disorders, but no reports are documented to date in endometriosis. Sequencing of mitochondrially encoded MMC-I subunits revealed 72 mutations of which 2 missense (G10398A; A13603A/G) mutations and 1 synonymous (T10400C) mutation showed higher prevalence in patients. In silico functional analysis predicted A13603A/G, a novel heteroplasmy as a 'damaging variant'. Our results indicate higher endometriosis risk for haplotype '10398A/10400C/13603AG' and haplogroup 'N'. Immunohistochemical analysis revealed elevated MMC-I expression in eutopic endometria of patients compared to controls. In conclusion, MMC-I alterations may constitute an inheritable risk factor for endometriosis.

A promise in the treatment of endometriosis: an observational cohort study on ovarian endometrioma reduction by N-acetylcysteine

Urged by the unmet medical needs in endometriosis treatment, often with undesirable side effects, and encouraged by N-acetylcysteine (NAC) efficacy in an animal model of endometriosis and by the virtual absence of toxicity of this natural compound, we performed an observational cohort study on ovarian endometriosis. NAC treatment or no treatment was offered to 92 consecutive Italian women referred to our university hospital with ultrasound confirmed diagnosis of ovarian endometriosis and scheduled to undergo laparoscopy 3 months later. According to patients acceptance or refusal, NAC-treated and untreated groups finally comprised 73 and 72 endometriomas, respectively. After 3 months, within NAC-treated patients cyst mean diameter was slightly reduced (−1.5 mm) versus a significant increase (+6.6 mm) in untreated patients (P = 0.001). Particularly, during NAC treatment, more cysts reduced and fewer cysts increased their size. Our results are better than those reported after hormonal treatments. Twenty-four NAC-treated patients—versus 1 within controls—cancelled scheduled laparoscopy due to cysts decrease/disappearance and/or relevant pain reduction (21 cases) or pregnancy (1 case). Eight pregnancies occurred in NAC-treated patients and 6 in untreated patients. We can conclude that NAC actually represents a simple effective treatment for endometriosis, without side effects, and a suitable approach for women desiring a pregnancy.

Regional treatment with liquid barrier agents: a novel therapeutic option for intraperitoneal endometriosis?

Endometriosis is a frequent gynecological disease, which is characterized by the presence of endometriotic lesions, i.e. ectopic endometrial glands and stroma, outside the uterine cavity. Most of these lesions are located in the peritoneal cavity, where they induce a chronic inflammatory and angiogenic tissue response. This is often associated with the formation of peritoneal adhesions. Accordingly, endometriosis is crucially dependent on the close interaction of the ectopic endometrial tissue with the peritoneum and the peritoneal fluid. Therefore, we hypothesize in the present paper that regional treatment of endometriosis, selectively targeting the peritoneal microenvironment without inducing severe systemic side effects, may represent a promising novel treatment strategy. This may be achieved by the application of liquid barrier agents, which are already well established in clinical practice for peritoneal dialysis, treatment of peritoneal surface malignancies and prevention of postoperative adhesions. Of interest, some of these agents have been shown to exhibit anti-inflammatory, anti-oxidant and anti-tumoral properties. Thus, they may act as pleiotropic compounds, affecting multiple mechanisms, which are involved in the pathogenesis of endometriosis.

Mitochondrial displacement loop alterations are associated with endometriosis

OBJECTIVE

To evaluate the association of mitochondrial displacement (D-) loop alterations with endometriosis in south Indian women.

DESIGN

Case-control study.

SETTING

Biochemistry and molecular biology laboratories.

PATIENT(S)

Women with (n = 152) and without (n = 150) endometriosis of south Indian origin.

INTERVENTION(S)

All women had a transvaginal ultrasound scan at screening followed by a laparoscopy to confirm the diagnosis (revised American Fertility Society stage III = 54; stage IV = 98).

MAIN OUTCOME MEASURE(S)

Genotyping of entire D-loop (1,124 bp) was carried out on genomic DNA of blood from cases and controls by polymerase chain reaction sequencing analysis.

RESULT(S)

Twelve novel mutations and 187 reported polymorphisms were identified in the D-loop region of cases and/or controls. The A189G, 310 C insertion, T16189C polymorphisms, and 189G/310TC/16189C haplotype have significantly higher frequency in cases compared with controls.

CONCLUSION(S)

Mitochondrial D-loop alterations may constitute an inheritable risk factor for endometriosis. The analysis of D-loop alterations may help to identify patients at high risk for disease outcome.

Disturbed balance between phase I and II metabolizing enzymes in ovarian endometriosis: a source of excessive hydroxy-estrogens and ROS?

Oxidative metabolism of estrogens was studied in 31 ovarian endometriosis and 29 normal endometrium samples, by qPCR. Expression was monitored for genes encoding five estrogen hydroxylating, five hydroxy (OH)-estrogen conjugating, and three estrogen quinone detoxifying enzymes. CYP1B1, COMT, NQO1, and GSTP1 protein levels were determined using Western blotting and immunohistochemistry staining. Increased expression of CYP1A1, CYP3A7 and COMT, and higher levels of MB-COMT were seen in endometriosis, as compared to normal endometrium. Expression of CYP1B1, CYP3A5, SULT1A1 and NQO2 was unchanged, with comparable CYP1B1 protein levels. Expression of SULT1E1, SULT2B1, UGT2B7, NQO1, and GSTP1 was decreased. Three NQO1 isoforms were detected; NQO1c appears to be endometriosis-specific. Our data indicate a disturbed balance between phase I and II metabolizing enzymes in endometriosis, potentially leading to excessive OH-estrogen and altered ROS formation, and stimulation of proliferation of ectopic endometrium. This is the first report on disturbed expression of estrogen oxidative metabolism genes in ovarian endometriosis.

Defining future directions for endometriosis research: workshop report from the 2011 World Congress of Endometriosis In Montpellier, France

Endometriosis, defined as estrogen-dependent lesions containing endometrial glands and stroma outside the uterus, is a chronic and often painful gynecological condition that affects 6% to 10% of reproductive age women. Endometriosis has estimated annual costs of US $12 419 per woman (approximately €9579), comprising one-third of the direct health care costs with two-thirds attributed to loss of productivity. Decreased quality of life is the most important predictor of direct health care and total costs. It has been estimated that there is a mean delay of 6.7 years between onset of symptoms and a surgical diagnosis of endometriosis, and each affected woman loses on average 10.8 hours of work weekly, mainly owing to reduced effectiveness while working. To encourage and facilitate research into this debilitating disease, a consensus workshop to define future directions for endometriosis research was held as part of the 11th World Congress on Endometriosis in September 2011 in Montpellier, France. The objective of this workshop was to review and update the endometriosis research priorities consensus statement developed following the 10th World Congress on Endometriosis in 2008.(1) A total of 56 recommendations for research have been developed, grouped under 6 subheadings: (1) diagnosis, (2) classification and prognosis, (3) clinical trials, treatment, and outcomes, (4) epidemiology, (5) pathophysiology, and (6) research policy. By producing this consensus international research priorities statement, it is the hope of the workshop participants that researchers will be encouraged to develop new interdisciplinary research proposals that will attract increased funding support for work on endometriosis.

An update on the pharmacological management of endometriosis

INTRODUCTION

Endometriosis is a common disease that causes pain symptoms and/or infertility in women in their reproductive years. The disease is characterised by the presence of endometrium-like tissue - glands and stroma - outside the uterine cavity. Different treatment options exist for endometriosis including medical and surgical treatments or a combination of the two approaches. The most commonly used medications are non-steroidal anti-inflammatory drugs, GnRH agonists, androgen derivatives such as danazol, combined oral contraceptive pills, progestogens and more recently the levonorgestrel intrauterine system.

AREAS COVERED

The authors review current medical treatments used for symptomatic endometriosis and also discuss new treatment approaches. The authors conducted a literature search for randomised controlled trials related to medical treatments of endometriosis in humans, searched the Cochrane library for reviews and also searched for registered trials that have not yet been published on ClinicalTrials.gov.

EXPERT OPINION

The medical treatment of endometriosis is effective at treating pain and preventing recurrence of disease after surgery. Remarkably, the oral contraceptive pill taken continuously is as effective as GnRH-a, while causing far less side-effects. Conversely, no treatment currently exists for enhancing fecundity in women whose infertility is associated with endometriosis. As all existing therapies of endometriosis are contraceptive, great efforts should be targeted at researching novel products that reduce the disease expression without shuttering ovulation.

Diet and endometriosis risk: a literature review

A connection between dietary factors and endometriosis onset has become a topic of interest mostly due to the observation that physiological and pathological processes of the disease can be influenced by diet. This paper systematically reviews prior publications dealing with this aspect in order to identify potentially modifiable risk factors. Comprehensive searches in the electronic databases MEDLINE, EMBASE and Science Citation Index Expanded were conducted to identify published studies evaluating the association between food intake (nutrients and food groups) and endometriosis. Eleven studies were identified: 10 case-control and one cohort study. Information on diet was collected using food frequency questionnaires in seven studies, while in one study the questionnaire focused on caffeine and alcohol intake. Women with endometriosis seem to consume fewer vegetables and omega-3 polyunsaturated fatty acids and more red meat, coffee and trans fats but these findings could not be consistently replicated. Most data have also been discussed herein in light of the available experimental and animal model results. At present, evidence supporting a significant association between diet and endometriosis is equivocal. Further studies are needed to clarify the role of diet on endometriosis risk and progression.

Oxidative cell injury as a predictor of endometriosis progression

BACKGROUND

There is increasing evidence that oxidative stress is one of the key factors for progression of endometriosis. In this prospective controlled trial, we measured 6 different biomarkers of oxidative stress targeting protein, lipid, and DNA to quantify the severity and progression of endometriosis and establish a diagnostic marker for the disease.

METHODS

A total of 62 consecutive patients were identified and enrolled in this study. After exclusion criteria, 44 patients were allocated to 3 groups: stage I/II (n = 14), stage III/IV (n = 16), and a control group (n = 14). The levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-oxoguanine DNA glycosylase (OGG1), protein carbonyl (PC), lipid peroxidation (LPO), reactive oxygen species (ROS), and total antioxidant capacity (TAC) were accessed in peritoneal fluid and tissue.

RESULTS

Significantly higher levels of 8-OHdG and PC were seen in patients with endometriosis, in addition OGG1 expression was found to be significantly lower in patients with endometriosis (P < .001, P = .001, P = .033, respectively); ROS, TAC, and LPO were similar in stages I/II, stages III/IV, and control group. A predictive model was built using multivariable analyses and receiver-operating characteristics curves. The ability to predict and distinguish between patients without endometriosis, stage I/II endometriosis, and stage III/IV was very high. This model was highly discriminatory and had a concordance index of 0.87.

CONCLUSION

In this cohort, higher DNA damage and lower DNA repair activity was related to endometriosis progression. Our results indicate that oxidative stress as a biomarker of cell injury can be used as a reliable quantitative test of endometriosis severity.

Interleukin-19 and interleukin-22 serum levels are decreased in patients with ovarian endometrioma

OBJECTIVE

To determine the serum levels of interleukin (IL)-10 family ILs in women with ovarian endometriosis and investigate the correlation of these levels with disease activity.

DESIGN

A case-control laboratory study.

SETTING

Tertiary-care university hospital.

PATIENT(S)

Two hundred nineteen women, with (n = 112) and without (n = 107) endometriosis.

INTERVENTION(S)

Complete surgical excision with pathological analysis.

MAIN OUTCOME MEASURE(S)

Blood samples were obtained during surgical procedures. IL-10, -19, -20, and -22 were assayed by ELISA in sera, and the concentrations correlated with the extent and the severity of the disease.

RESULT(S)

IL-19 was detectable in 18.3% and IL-22 in 47.9% of sera samples from all 219 women studied. Serum IL-19 was lower in women with endometriosis (median, 292.7 pg/mL; range, 32.2-1,339.3) than in endometriosis-free women (median, 1,035.8 pg/mL; range, 32.2-2,000.0). In addition, serum IL-22 levels were decreased in women affected by endometriosis (median, 352.0 pg/mL; range, 31.2-1,392.2) as compared with endometriosis-free women (median, 709.2 pg/mL; range, 73.3-2,012.0). We found significant correlations between serum IL-22 concentrations and intensity of deep dyspareunia (r = -0.303) and noncyclic chronic pelvic pain (r = -0.212). IL-19 was correlated with the intensity of deep dyspareunia (r = -0.749).

CONCLUSION(S)

Serum IL-19 and IL-22 are decreased in women with ovarian endometrioma. IL-10 family ILs may be involved in the pathogenesis of endometriosis.

Aberrant expression of the mammalian target of rapamycin, hypoxia-inducible factor-1α, and glucose transporter 1 in the development of ovarian clear-cell adenocarcinoma

Ovarian clear-cell adenocarcinoma (CCA) is known to be a type of cancer in humans with a high frequency of expression of the mammalian target of rapamycin (mTOR), hypoxia-inducible factor-1 (HIF-1), and glucose transporter 1 (Glut1). In this study, we aimed to determine how these alterations contribute to tumor development of CCAs. Immunohistochemical expressions of phosphorylated-mTOR (p-mTOR), HIF-1α, and Glut1 were analyzed in 36 CCAs and 60 coexistent putative precursor lesions: 19 nonatypical and 16 atypical endometriotic lesions, and 11 benign and 14 borderline clear-cell adenofibroma (CCAF) components. Twenty-one cases with solitary endometriosis were also examined. The frequencies of immunopositivity for p-mTOR (in cytoplasm or nucleus), HIF-1α (in nucleus), and Glut1 increased in accordance with higher cytological atypia in the putative precursors: 58%, 5%, and 16% in the nonatypical endometriosis; 63%, 37%, and 50% in the atypical endometriosis; 77%, 95%, and 95% in the endometriosis-associated CCAs; 27%, 0%, and 0% in the benign-CCAF components; 64%, 79%, and 43% in the borderline CCAF components; and 71%, 100%, and 93% in the CCAF-associated CCAs, respectively. p-mTOR, HIF-1α (in the nucleus), and Glut1 were positive in 10%, 5%, and 19% of the solitary endometriosis, respectively. In the putative precursor lesions coexisting with CCA, a strong correlation in the expression between p-mTOR and HIF-1α and between HIF-1α and Glut1 was identified. Expressions of p-mTOR, HIF-1α, and Glut1 have already been evident in the putative precursor lesions of CCA, and these alterations cumulatively occur in the development of ovarian CCA.

Mitochondrial genome variations in advanced stage endometriosis: a study in South Indian population

BACKGROUND

Endometriosis is a chronic gynecological benign disease that shares several features similar to malignancy. Mitochondrial DNA (mtDNA) mutations have been reported in all most all types of tumors. However, it is not known as to whether mtDNA mutations are associated with endometriosis.

METHODOLOGY

We sequenced the entire mitochondrial genome of analogous ectopic and eutopic endometrial tissues along with blood samples from 32 advanced stage endometriosis patients to analyze the role of somatic and germ-line mtDNA variations in pathogenesis of endometriosis. All ectopic tissues were screened for tumor-specific mtDNA deletions and microsatellite instability (MSI). We also performed mtDNA haplogrouping in 128 patients and 90 controls to identify its possible association with endometriosis risk.

PRINCIPAL FINDINGS

We identified 51 somatic (novel: 31; reported: 20) and 583 germ-line mtDNA variations (novel: 53; reported: 530) in endometriosis patients. The A13603G, a novel missense mutation which leads to a substitution from serine to glycine at the codon 423 of ND5 gene showed 100% incidence in ectopic tissues. Interestingly, eutopic endometrium and peripheral leukocytes of all the patients showed heteroplasmy (A/G; 40-80%) at this locus, while their ectopic endometrium showed homoplasmic mutant allele (G/G). Superimposition of native and mutant structures of ND5 generated by homology modeling revealed no structural differences. Tumor-specific deletions and MSI were not observed in any of the ectopic tissues. Haplogrouping analysis showed a significant association between haplogroup M5 and endometriosis risk (P: 0.00069) after bonferroni correction.

CONCLUSIONS

Our findings substantiate the rationale for exploring the mitochondrial genome as a biomarker for the diagnosis of endometriosis.

Oxidative stress biomarkers in patients with endometriosis: systematic review

PURPOSE

Since the first description about oxygen toxicity made by Joseph Priestley, the oxidative stress has been enrolled as a key factor in the pathogenesis of endometriosis. Our aim was to review oxidative stress biomarkers measured in patients with endometriosis.

METHODS

Relevant studies were identified by searches of the MEDLINE database from 1990 to March 2011 using endometriosis, free radical and oxidative stress as mesh terms. We only included manuscripts in English, and review articles were excluded. In addition, free radical chemistry and oxidative stress history were discussed.

RESULTS

After inclusion and exclusion criteria, 19 articles were selected to be included in this systematic review. A total of 36 oxidative stress biomarkers (20 different markers) were measured in patients with endometriosis. Some of the markers were measured in more than one manuscript. They were arranged in five subgroups: Enzymatic activity (n = 3), Anions/free radicals (n = 5), Lipoperoxidation markers (n = 7), DNA Damage markers (n = 1), and Protein oxidation (n = 4). Of those 36 markers, 23 were found to be significantly higher in patients with endometriosis comparing with control patients.

CONCLUSION

Oxidative stress plays an important role in the pathogenesis and progression of endometriosis.

The effects of oxidative stress on female reproduction: a review

Oxidative stress (OS), a state characterized by an imbalance between pro-oxidant molecules including reactive oxygen and nitrogen species, and antioxidant defenses, has been identified to play a key role in the pathogenesis of subfertility in both males and females. The adverse effects of OS on sperm quality and functions have been well documented. In females, on the other hand, the impact of OS on oocytes and reproductive functions remains unclear. This imbalance between pro-oxidants and antioxidants can lead to a number of reproductive diseases such as endometriosis, polycystic ovary syndrome (PCOS), and unexplained infertility. Pregnancy complications such as spontaneous abortion, recurrent pregnancy loss, and preeclampsia, can also develop in response to OS. Studies have shown that extremes of body weight and lifestyle factors such as cigarette smoking, alcohol use, and recreational drug use can promote excess free radical production, which could affect fertility. Exposures to environmental pollutants are of increasing concern, as they too have been found to trigger oxidative states, possibly contributing to female infertility. This article will review the currently available literature on the roles of reactive species and OS in both normal and abnormal reproductive physiological processes. Antioxidant supplementation may be effective in controlling the production of ROS and continues to be explored as a potential strategy to overcome reproductive disorders associated with infertility. However, investigations conducted to date have been through animal or in vitro studies, which have produced largely conflicting results. The impact of OS on assisted reproductive techniques (ART) will be addressed, in addition to the possible benefits of antioxidant supplementation of ART culture media to increase the likelihood for ART success. Future randomized controlled clinical trials on humans are necessary to elucidate the precise mechanisms through which OS affects female reproductive abilities, and will facilitate further explorations of the possible benefits of antioxidants to treat infertility.

Xanthohumol inhibits growth and vascularization of developing endometriotic lesions

BACKGROUND

Xanthohumol is a prenylated flavonoid isolated from hops, which is known to act as a pleiotropic cancer chemopreventive agent owing to its anti-proliferative, anti-inflammatory and anti-angiogenic properties. In the present study, we analyzed, for the first time, whether this dietary compound may also be used for the treatment of endometriosis.

METHODS

Peritoneal and mesenteric endometriotic lesions were surgically induced in BALB/c mice by uterine tissue transplantation into the abdominal cavity. The animals were treated daily with 100 µM xanthohumol (n= 8) or vehicle (control, n= 8) via the drinking water, starting 3 days before tissue transplantations. Lesion growth, cyst formation and vascularization were subsequently analyzed by means of high-resolution ultrasound imaging (at Day 0 and then once per week for 28 days), caliper measurements, western blotting, histology and immunohistochemistry over 4 weeks.

RESULTS

In the treatment and control groups, uterine grafts developed typical endometriotic lesions with cyst-like dilated glands surrounded by a vascularized endometrial stroma. However, xanthohumol efficiently decreased the size of these lesions at Day 28, independent of their localization within the peritoneal cavity, compared with control (peritoneal: P =0.041; mesenteric: P =0.038). This was associated with a reduced level of phosphoinositide 3-kinase protein. Moreover, vascularization of xanthohumol-treated lesions was suppressed, as indicated by a significantly lower microvessel density at Day 28 when compared with vehicle-treated controls (peritoneal: P =0.026; mesenteric: P =0.004). Additional analyses revealed that treatment with xanthohumol did not affect the histomorphology, proliferation and vascularization of the uterine horns and ovaries.

CONCLUSIONS

Taken together, these experimental findings suggest that xanthohumol inhibits the development of endometriotic lesions in mice without inducing serious side effects in the reproductive organs. Thus, xanthohumol represents a promising dietary phytochemical that, after further testing, may be considered for the use in the selective treatment of endometriotic lesions.

New treatment strategies and emerging drugs in endometriosis

Introduction: Endometriosis, histologically defined as the presence of endometrium-like tissue - glands and stroma - that develops outside of the uterine cavity, is still an enigmatic disease responsible for pelvic pain and infertility. The current treatments of endometriosis are surgery and hormonal therapies that act by suppressing ovulation and/or directly on steroid receptors located in endometriotic lesions. Areas covered: New hormonal and non-hormonal therapies are being developed for the treatment of endometriosis-related pain. The authors review the state of advancement and the results of novel treatments studied in registered trials ( www.ClinicalTrials.gov ). Cellular signaling pathways activated in endometriotic cells, which constitute potential targets for future treatments, are also described. Expert opinion: Therapeutic research efforts should focus on identifying and testing substances capable of acting locally on the lesions themselves, without interfering with ovulation, in order to be efficacious on both pain symptoms and infertility.

PI3K-Akt-mTOR and MAPK signaling pathways in polycystic ovarian syndrome, uterine leiomyomas and endometriosis: an update

PI3K-Akt-mTOR and MAP kinase are two important cell signaling pathways that are activated by steroid hormones and growth factors leading to cellular events including gene expression, cell proliferation and survival. These pathways are considered as an attractive target for the development of novel anticancer molecules, and selective inhibitors specifically targeting different components of these cascades have been developed. This review summarizes the current available knowledge on the PI3K-Akt-mTOR and MAPK pathways and their targeting in estrogen-dependent benign gynecological disorders viz. polycystic ovarian syndrome, uterine leiomyomas and endometriosis, which are a significant cause of high morbidity in women of reproductive age group. Increasing knowledge about the role of the two growth regulatory pathways in the pathogenesis of these disorders may give the opportunity to use specific signal transduction inhibitors for management of these patients in future.

Ovarian endometrioma: severe pelvic pain is associated with deeply infiltrating endometriosis

BACKGROUND

The objective of this study was to evaluate the significance of severe preoperative pain for patients presenting with ovarian endometrioma (OMA).

METHODS

Three hundred consecutive patients with histologically proven OMA were enrolled at a single university tertiary referral centre between January 2004 and May 2010. Complete surgical excision of all recognizable endometriotic lesions was performed for each patient. Pain intensity was assessed with a 10-cm visual analogue scale (VAS). Pain was considered as severe when VAS was ≥ 7. Prospective preoperative assessment of type and severity of pain symptoms (VAS) was compared with the peroperative findings (surgical removal and histological analysis) of endometriomas and associated deeply infiltrating endometriosis. Correlations were sought with univariate analysis and a multiple regression logistic model.

RESULTS

After multiple logistic regression analysis, uterosacral ligaments involvement was related with a high severity of chronic pelvic pain [odds ratios (OR) = 2.1; 95% confidence interval (CI): 1.1-4.3] and deep dyspareunia (OR = 2.0; 95% CI: 1.1-3.5); vaginal involvement was related with a higher intensity of lower urinary symptoms (OR = 13.4; 95% CI: 3.2-55.8); intestinal involvement was related with an increased severity of dysmenorrhoea (OR = 5.2; 95% CI: 2.7-10.3) and gastro-intestinal symptoms (OR = 7.1; 95% CI: 3.3-15.3).

CONCLUSIONS

In case of OMA, severe pelvic pain is significantly associated with deeply infiltrating lesions. In this situation, the practitioner should perform an appropriate preoperative imaging work-up in order to evaluate the existence of associated deep nodules and inform the patient in order to plan the surgical intervention strategy.

Lipoxin A4 inhibits the development of endometriosis in mice: the role of anti-inflammation and anti-angiogenesis

PROBLEM

To evaluate the effects of the anti-inflammatory and anti-angiogenic roles of LXA4 on endometriosis in mice.

METHOD OF STUDY

Endometriosis was induced in 40 mice and separated into two groups. LXA4 group was administered by LXA4 for 3 weeks. The endometriotic lesions were counted, measured, and identified by pathology. The presence of a panel of pro-inflammatory factors was assessed by real-time RT-PCR, and enzyme-linked immunoassay, the mRNA, protein levels of matrix metalloproteinase (MMPs), and vascular endothelial growth factor (VEGF) were determined by real-time RT-PCR and immunohistochemistry; the activity of MMPs was evaluated by gelatin zymography.

RESULTS

Treatment with LXA4 significantly inhibited endometriotic lesion development (13.58 ± 4.01 mm(2) in LXA4 group and 23.20 ± 7.49 mm(2) , P = 0.0002), downregulated pro-inflammatory factors, suppressed the activity of MMP9, and reduced the VEGF levels associated with endometriosis in mice.

CONCLUSION

LXA4 may inhibit the progression of endometriosis possibly by anti-inflammation and anti-angiogenesis.

Infertility and chylous ascites? A case report

INTRODUCTION

Chylous ascites is defined by an accumulation of chylous fluid in the peritoneal cavity and it clinically appears as a milky fluid in which laboratory examination reveals triglycerides, cholesterol, and sometimes chylomicrons and lymphocytes.

PRESENTATION OF CASE

We report the first case of primary chylous ascites observed during laparoscopy for unexplained secondary infertility.

DISCUSSION

Chylous ascites has never been linked to fertility but bathes all internal reproductive organs surfaces and is considered a communication mean between ovaries.

CONCLUSION

Despite a lack of evidence, the question of peritoneal fluid role remains in infertility.

[Intestinal endometriosis]

Endometriosis affects 6 to 10 % of all women of childbearing age. Intestinal involvement is defined by muscularis infiltration and has been estimated to occur in 8 % to 12 % of women with endometriosis. The most common sites are rectum, sigmoid and ileocaecal junction. In most cases, intestinal endometriosis is associated with deep infiltrating endometriosis, multifocal and aggressive form of endometriosis, responsible for refractory pelvic pain and infertility. The symptoms are nonspecific but are characterized by cyclic exacerbation of pain. The preoperative work-up includes a rectal endoscopic ultrasonography, a transvaginal ultrasonography, a pelvic magnetic resonance imaging and a multidetector CT scan. There is currently no cure other than surgical removal of lesions. Medical treatments are based on a hormone used to block ovarian function.

The 'incessant menstruation' hypothesis: a mechanistic ovarian cancer model with implications for prevention

Serous, endometrioid, clear cell and mucinous histotypes are the most common epithelial ovarian cancer. Most serous cancers appear to originate from precursor lesions at the fimbriated tubal end, whereas most endometrioid and clear cell cancers seem to derive from atypical endometriosis. Data regarding hormonal factors and associated gynaecologic conditions were critically analysed with the objective of defining a carcinogenic model for sporadic epithelial ovarian cancer complying with epidemiologic and pathologic findings. Oral contraceptives and tubal ligation substantially reduce the risk of serous, endometrioid and clear cell subgroups, but have no significant effect on mucinous tumours, which probably follow a different oncogenic pathway. We hypothesize that serous, endometrioid and clear cell cancers share a common pathogenic mechanism, i.e. iron-induced oxidative stress derived from retrograde menstruation. Fimbriae floating in bloody peritoneal fluid are exposed to the action of catalytic iron and to the genotoxic effect of reactive oxygen species, generated from haemolysis of erythrocytes by pelvic macrophages. This would explain the distal site of tubal intraepithelial neoplasia. Collection of blood inside endometriomas would lead to the same type of genotoxic insult on gonadal endometrial implants. This would explain why endometriosis-associated cancers develop much more frequently in the ovary than at extragonadal sites. In women not seeking conception, bilateral salpingectomy could be advised whenever planning surgery for independent indications, thus possibly reducing cancer risk, while preserving ovarian function. The use of oral contraceptives should be favoured for prolonged periods of time, especially in women with endometriosis, a population at doubled risk of gonadal malignancy.

The mTOR/AKT inhibitor temsirolimus prevents deep infiltrating endometriosis in mice

Deep infiltrating endometriosis (DIE) is a particular clinical and histological entity of endometriosis responsible for chronic pelvic pain and infertility. Here we characterize the proliferative phenotype of DIE cells, to explore the cellular and molecular mechanisms that could explain their aggressive potential. In addition, the inhibition of mTOR/AKT pathway was tested, as a potential treatment of DIE. Included were 22 patients with DIE and 12 control patients without endometriosis. Epithelial and stromal cells were extracted from biopsies of eutopic endometrium and deep infiltrating endometriotic nodules from patients with DIE. Cell proliferation was determined by thymidine incorporation. Oxidative stress was assayed by spectrofluorometry. The ERK and mTOR/AKT pathways were analyzed in vitro by Western blot and for AKT in vivo in a mouse model of DIE. The proliferation rate of eutopic endometrial cells and of deep infiltrating endometriotic cells from DIE patients was higher than that of endometrial cells from controls. The hyperproliferative phenotype of endometriotic cells was associated with an increase in endogenous oxidative stress, and with activation of the ERK and mTOR/AKT pathways. mTOR/AKT inhibition by temsirolimus decreased endometriotic cell proliferation both in vitro and in vivo in a mouse model of DIE. Blocking the mTOR/AKT pathway offers new prospects for the treatment of DIE.

New insights into the pathophysiology of endometriosis: from chronic inflammation to danger signal

BACKGROUND

Various theories try to explain the development and progression of endometriosis, however, no single theory can explain all aspects of this disorder. Gene expression profiling studies might reveal factors that explain variability in disease development and progression, which can serve as specific biomarkers for endometriosis and novel drug development. We have recently showed that the upregulated genes were predominantly clustered in stress and detoxification, providing a mechanistic explanation for the oxidative stress and chronic inflammatory response in endometriosis.

OBJECTIVE

This review aims: (1) to analyse the published data, with the aim of identifying pathways consistently regulated by the endometriosis genotype and (2) to summarise the findings of specific genes, which are involved in the process of oxidative stress and inflammation.

METHODS

We identified gene array and proteomics studies whose data were accessible in PubMed.

RESULTS

A major finding is the increased expressions of several markers including heat shock protein, S100, fibronectin, and neutrophil elastase, which might be involved in the process of Toll-like receptor (TLR)-dependent sterile inflammation. The study reviews a convergence in the main pathogenic process, where the TLR-mediated inflammation occurs possibly through the endogenous ligands.

CONCLUSIONS

In conclusion, a circulus vitiosus of both the oxidative stress pathway and the TLR pathways is generated when the process becomes chronic (danger signal spiral).

Differential immune and genetic responses in rat models of Crohn's colitis and ulcerative colitis

Crohn's disease and ulcerative colitis are clinically, immunologically, and morphologically distinct forms of inflammatory bowel disease (IBD). However, smooth muscle function is impaired similarly in both diseases, resulting in diarrhea. We tested the hypothesis that differential cellular, genetic, and immunological mechanisms mediate smooth muscle dysfunction in two animal models believed to represent the two diseases. We used the rat models of trinitrobenzene sulfonic acid (TNBS)- and dextran sodium sulfate (DSS)-induced colonic inflammations, which closely mimic the clinical and morphological features of Crohn's disease and ulcerative colitis, respectively. DSS inflammation induced oxidative stress initially in mucosa/submucosa, which then propagated to the muscularis externa to impair smooth muscle function. The muscularis externa showed no increase of cytokines/chemokines. On the other hand, TNBS inflammation almost simultaneously induced oxidative stress, recruited or activated immune cells, and generated cytokines/chemokines in both mucosa/submucosa and muscularis externa. The generation of cytokines/chemokines did not correlate with the recruitment and activation of immune cells. Consequently, the impairment of smooth muscle function in DSS inflammation was primarily due to oxidative stress, whereas that in TNBS inflammation was due to both oxidative stress and proinflammatory cytokines. The impairment of smooth muscle function in DSS inflammation was due to suppression of Gα(q) protein of the excitation-contraction coupling. In TNBS inflammation, it was due to suppression of the α(1C)1b subunit of Ca(v)1.2b channels, CPI-17 and Gα(q). TNBS inflammation increased IGF-1 and TGF-β time dependently in the muscularis externa. IGF-1 induced smooth muscle hyperplasia; both IGF-1 and TGF-β induced hypertrophy. In conclusion, both TNBS and DSS induce transmural inflammation, albeit with different types of inflammatory mediators. The recruitment or activation of immune cells does not correlate directly with the intensity of generation of inflammatory mediators. The inflammatory mediators in TNBS and DSS inflammations target different genes to impair smooth muscle function.

Questioning patients about their adolescent history can identify markers associated with deep infiltrating endometriosis

OBJECTIVE

To investigate whether the clinical history, particularly of the adolescence period, contains markers of deeply infiltrating endometriosis (DIE).

DESIGN

Cross-sectional study.

SETTING

Universitary tertiary referral center.

PATIENT(S)

Two hundred twenty-nine patients operated on for endometriosis. Endometriotic lesions were histologically confirmed as non-DIE (superficial peritoneal endometriosis and/or ovarian endometriomas) (n = 131) or DIE (n = 98).

INTERVENTION(S)

Surgical excision of endometriotic lesions with pathological analysis of each specimens.

MAIN OUTCOME MEASURE(S)

Epidemiological data, pelvic pain scores, family history of endometriosis, absenteeism from school during menstruation, oral contraceptive (OC) pill use.

RESULT(S)

Patients with DIE had significantly more positive family history of endometriosis (odds ratio [OR] = 3.2; 95% confidence interval [CI]: 1.2-8.8) and more absenteeism from school during menstruation (OR = 1.7; 95% CI: 1-3). The OC pill use for treating severe primary dysmenorrhea was more frequent in patients with DIE (OR = 4.5; 95% CI: 1.9-10.4). Duration of OC pill use for severe primary dysmenorrhea was longer in patients with DIE (8.4 ± 4.7 years vs. 5.1 ± 3.8 years). There was a higher incidence of OC pill use for severe primary dysmenorrhea before 18 years of age in patients with DIE (OR = 4.2; 95% CI: 1.8-10.0).

CONCLUSION(S)

The knowledge of adolescent period history can identify markers that are associated with DIE in patients undergoing surgery for endometriosis.

Antiproliferative effects of cannabinoid agonists on deep infiltrating endometriosis

Deep infiltrating endometriosis (DIE) is characterized by chronic pain, hyperproliferation of endometriotic cells and fibrosis. Since cannabinoids are endowed with antiproliferative and antifibrotic properties, in addition to their psychogenic and analgesic effects, cannabinoid agonists have been evaluated in DIE both in vitro and in vivo. The in vitro effects of the cannabinoid agonist WIN 55212-2 were evaluated on primary endometriotic and endometrial stromal and epithelial cell lines extracted from patients with or without DIE. Cell proliferation was determined by thymidine incorporation and production of reactive oxygen species by spectrofluorometry. ERK and Akt pathways were studied by immunoblotting. Immunoblotting of α-smooth muscle actin was studied as evidence of myofibroblastic transformation. The in vivo effects of WIN 55212-2 were evaluated on Nude mice implanted with human deep infiltrating endometriotic nodules. The in vitro treatment of stromal endometriotic cells by WIN 55212-2 decreased cell proliferation, reactive oxygen species production, and α-smooth muscle actin expression. The decrease in cell proliferation induced by WIN 55212-2 was not associated with a decrease in ERK activation, but was associated with the inhibition of Akt activation. WIN 55212-2 abrogated the growth of endometriotic tissue implanted in Nude mice. Cannabinoid agonists exert anti-proliferative effects on stromal endometriotic cells linked to the inhibition of the Akt pathway. These beneficial effects of cannabinoid agonists on DIE have been confirmed in vivo.

Protein kinase inhibitors can control the progression of endometriosis in vitro and in vivo

Endometriosis affects 6-10% of women in their reproductive years, causing chronic pelvic pain and infertility. Its pathogenesis remains poorly understood and current treatments, based on hormonal therapy or surgery, are often insufficient. The purpose of our study was to investigate the role of the ERK pathway in the development of endometriosis and to test the effects of protein kinase inhibitors on the proliferation of endometriotic cells in vitro and in vivo. We studied ex vivo human endometrial and endometriotic cells in culture. Stromal and epithelial cells were extracted from endometrial and endometriotic biopsies from patients with endometriosis and from patients without endometriosis. The ERK pathway was explored by western blot on cell lysates and by ELISA on total crushed specimens of endometrium. Cells in culture were treated with A771726, PD98059, and U0126. Human endometriotic lesions were implanted in nude mice. Mice were treated with A771726, leflunomide, PD98059, U0126 or PBS during 2 weeks before sacrifice and extraction of the endometriotic implants for histological examination. We found that the ERK pathway was significantly activated in endometriotic cells and in endometrial cells from patients with endometriosis compared to endometrial cells of control patients, both by ELISA and by western blot. This phenomenon was associated with an increased proliferation of endometriotic cells compared to endometrial cells. Treating endometriotic cells with A771726, PD98059 or U0126 abrogated the phosphorylation of ERK and significantly decreased the cellular proliferation in vitro. In vivo, A771726, leflunomide, PD98059, and U0126 controlled the growth of endometriotic implants in the mouse model of endometriosis. Our study shows that protein kinase inhibitors could be new candidates to treat endometriosis. However, further studies are needed to evaluate their effects and tolerability in humans.

Endometriosis and infertility: pathophysiology and management

Endometriosis and infertility are associated clinically. Medical and surgical treatments for endometriosis have different effects on a woman's chances of conception, either spontaneously or via assisted reproductive technologies (ART). Medical treatments for endometriosis are contraceptive. Data, mostly uncontrolled, indicate that surgery at any stage of endometriosis enhances the chances of natural conception. Criteria for non-removal of endometriomas are: bilateral cysts, history of past surgery, and altered ovarian reserve. Fears that surgery can alter ovarian function that is already compromised sparked a rule of no surgery before ART. Exceptions to this guidance are pain, hydrosalpinges, and very large endometriomas. Medical treatment-eg, 3-6 months of gonadotropin-releasing hormone analogues-improves the outcome of ART. When age, ovarian reserve, and male and tubal status permit, surgery should be considered immediately so that time is dedicated to attempts to conceive naturally. In other cases, the preference is for administration of gonadotropin-releasing hormone analogues before ART, and no surgery beforehand. The strategy of early surgery, however, seems counterintuitive because of beliefs that milder non-surgical options should be offered first and surgery last (only if initial treatment attempts fail). Weighing up the relative advantages of surgery, medical treatment and ART are the foundations for a global approach to infertility associated with endometriosis.

More than antioxidant: N-acetyl-L-cysteine in a murine model of endometriosis

N-acetyl-L-cysteine exerts a complex action on endometrial cells, involving regulation of gene expression and protein activity and location, all converging into a decreased proliferation and a switch toward a differentiating, less invasive, and less inflammatory phenotype. Also considering the lack of undesired side effects, including unaffected fertility potential, this suggests a beneficial use of NAC in endometriosis clinical treatment.