The combination of N-acetyl cysteine, alpha-lipoic acid, and bromelain shows high anti-inflammatory properties in novel in vivo and in vitro models of endometriosis

Bromelain as a natural anti-inflammatory drug: a systematic review

Inflammation is a complex and necessary mechanism of an organ's response to biological, chemical and/or physical stimuli. In recent years, investigations on natural compounds with therapeutic actions for the treatment of different diseases have increased. Among these compounds, bromelain is highlighted, as a cysteine protease isolated from the Ananas comosus (pineapple) stem. This review aimed to evaluate the anti-inflammatory activity of bromelain, as well as its pathways on inflammatory mediators, through a systematic review with in vitro studies on different cell lines. The search was performed in PubMed, Science Direct, Scopus, Cochrane Library and Web of Science databases. Bromelain reduced IL-1β, IL-6 and TNF-α secretion when immune cells were already stimulated in an overproduction condition by proinflammatory cytokines, generating a modulation in the inflammatory response through prostaglandins reduction and activation of a cascade reactions that trigger neutrophils and macrophages, in addition to accelerating the healing process.

A Pilot Prospective Study Evaluating the Effect of Curcuma-Based Herbal Food Supplement on the Outcome of In Vitro Fertilization in Patients Testing Positive for Four Immunological Biomarkers

Background and Objectives: Inflammation and oxidative stress have been described to reduce the chance for pregnancy instauration and maintenance. NOFLAMOX, a recently developed herbal preparation with recognized antioxidant and anti-inflammatory properties, can represent an interesting treatment to increase the chance of pregnancy, both physiological or after in vitro fertilization (IVF). The aim of this study was to assess NOFLAMOX's effect; a population with unexplained infertility was screened for the recently described IMMUNOX panel based on four immunological biomarkers with a prospective study approach. Materials and Methods: Patients with unexplained infertility and positive for at least one of the biomarkers of the IMMUNOX panel were included in this study and treated with NOFLAMOX for three months prior to an IVF cycle. Results: Eighty-six patients (n = 86) were screened with the IMMUNOX panel and the forty-seven (54.5%) found positive were included in this study. In more detail, 11 were positive for TNFα (23.4%), 18 (38.3%) for glycodelin (GLY), 29 (61.7%) for Total Oxidative Status (TOS), and 32 (68.1%) for Complement Activity Toxic Factor (CATF). After three months of treatment, a significant reduction in the number of IMMUNOX-positive patients was observable, with 26 patients who turned IMMUNOX-negative displaying a quantitative statistically significant variation of 100% (11/11), 38.9% (7/18), 65.5% (18/29), and 75% (24/32), for TNFα, glycodelin, TOS, and CATF, respectively. Followed in the subsequent IVF cycle, this NOFLAMOX-treated population showed a pregnancy rate of 42.3% compared to the 4.7% of the IMMUNOX-positive group of patients. Conclusions: Taken together, the results of this study suggest that NOFLAMOX could represent an interesting option for those patients with unexplained infertility of inflammatory/oxidative origin. Further studies are needed to confirm these results and explore possible strategies to restore fertility in women with immune-mediated sterility.

Bioinformatics and integrated pharmacology network to identify the therapeutic targets and potential molecular mechanism of alpha-lipoic acid on primary ovarian insufficiency

Women experiencing primary ovarian insufficiency (POI) are more likely to experience infertility, and its incidence is increasing worldwide annually. Recently, the role of alpha-lipoic acid (ALA) in the treatment of POI has been reported. However, details of the potential pharmacological targets and related molecular pathways of ALA remain unclear and need to be elucidated. Thus, this study aims to elucidate the potential therapeutic target and related molecular mechanism of ALA on POI. First, the potential targets of POI and ALA-related targets were downloaded from online public databases. Subsequently, the overlapped target genes between POI and ALA were acquired, and gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG) analysis, protein-protein interaction (PPI) networks were performed and constructed. Finally, molecular docking was performed to verify protein-to-protein effect. A total of 152 potential therapeutic targets were identified. The biological processes of the intersecting targets were mainly involved in the cellular response to peptides, response to xenobiotic stimuli, and response to peptide hormones. The highly enriched pathways were the cAMP, PI3K/AKT, estrogen, progesterone mediated oocyte maturation, and apoptosis signaling pathways. The top 10 hub targets for ALA in the treatment of POI were STAT3, STAT1, CASP3, MTOR, PTGS2, CASP8, HSP90AA1, PIK3CA, MAPK1, and ESR1. The binding between ALA and all top hub targets were verified using the molecular docking analysis. In summary, using the systematic integrated pharmacology network and bioinformatics analysis, this study illustrated that ALA participates in the treatment of POI via multiple targets and multiple pathways mechanisms.

A comprehensive overview on the anti-inflammatory, antitumor, and ferroptosis functions of bromelain: an emerging cysteine protease

INTRODUCTION

Bromelain belongs to the cysteine protease endopeptidase class of enzymes isolated from the stem and fruit tissue component of Ananas comosus. The commercial and translational therapeutic potential of bromelain is ever increasing due to its augmented stability, easier purification, and salubrious pan-cancer effects.

AREAS COVERED

This paper presents the current state of knowledge about the isolation methods of bromelain, its safety, efficacy and tolerability. In addition, bromelains<apos;> role in eliciting pharmacological effects and its healing ability to mitigate cancer side effects based on accumulated in vitro, in vivo, and clinical evidence is relatively considerable.

EXPERT OPINION

Identification of molecular targets and crucial signalling pathways that bromelain regulates suggest it genuinely prospects for combating cancer and mitigation of chemotherapy or radiotherapy mediated side effects. Further research on the development of bromelain-entrapped drug delivery systems for augmented enzyme stability, processing ability and translational potential against cancer can be beneficial.

Dietary supplements for treatment of endometriosis: A review

As search for optimal therapy continues for endometriosis, aid of dietary supplements is gaining attention. Supplements can be used for their anti-inflammatory, anti-oxidant, anti-proliferative and immune modulatory charactheristics. We reviewed the literature, evaluated and synthesized effects of vitamin D, zinc, magnesium, omega 3, propolis, quercetin, curcumin, N-acetylcysteine, probiotics, resveratrol, alpha lipoic acid, vitamin C, vitamin E, selenium and epigallocatechin-3-gallate. Based on results of in vitro, animal and human studies, it might be safe to say that dietary supplements can be used as a complementary treatment for endometriosis.

Effectiveness of Dietary Interventions in the Treatment of Endometriosis: a Systematic Review

A patients' increasing interest in dietary modifications as a possible complementary or alternative treatment of endometriosis is observed. Unfortunately, the therapeutic potential of dietary interventions is unclear and to date no guidelines to assist physicians on this topic exist. The aim of this study, therefore, was to systematically review the existing studies on the effect of dietary interventions on endometriosis. An electronic-based search was performed in MEDLINE and COCHRANE. We included human and animal studies that evaluated a dietary intervention on endometriosis-associated symptoms or other health outcomes. Studies were identified and coded using standard criteria, and the risk of bias was assessed with established tools relevant to the study design. We identified nine human and 12 animal studies. Out of the nine human studies, two were randomized controlled trials, two controlled studies, four uncontrolled before-after studies, and one qualitative study. All of them assessed a different dietary intervention, which could be classified in one of the following principle models: supplementation with selected dietary components, exclusion of selected dietary components, and complete diet modification. Most of the studies reported a positive effect on endometriosis; they were however characterized by moderate or high-risk bias possibly due to the challenges of conducting dietary intervention trials. According to the available level of evidence, we suggest an evidence-based clinical approach for physicians to use during consultations with their patients. Further well-designed randomized controlled trials are needed to accurately determine the short-term and long-term effectiveness and safety of different dietary interventions.

Niclosamide suppresses macrophage-induced inflammation in endometriosis†

Endometriosis is a common gynecological disease, which causes chronic pelvic pain and infertility in women of reproductive age. Due to limited efficacy of current treatment options, a critical need exists to develop new and effective treatments for endometriosis. Niclosamide is an efficacious and FDA-approved drug for the treatment of helminthosis in humans that has been used for decades. We have reported that niclosamide reduces growth and progression of endometriosis-like lesions via targeting STAT3 and NFĸB signaling in a mouse model of endometriosis. To examine the effects of niclosamide on macrophage-induced inflammation in endometriosis, a total of 29 stage III-IV endometrioma samples were used to isolate human endometriotic stromal cells (hESCs). M1 or M2 macrophages were isolated and differentiated from fresh human peripheral blood samples. Then, hESCs were cultured in conditioned media (CM) from macrophages with/without niclosamide. Niclosamide dose dependently reduced cell viability and the activity of STAT3 and NFκB signaling in hESCs. While macrophage CM stimulated cell viability in hESCs, niclosamide inhibited this stimulation. Macrophage CM stimulated the secretion of proinflammatory cytokines and chemokines from hESCs. Most of these secreted factors were inhibited by niclosamide. These results indicate that niclosamide is able to reduce macrophage-induced cell viability and cytokine/chemokine secretion in hESCs by inhibiting inflammatory mechanisms via STAT3 and/or NFκB signaling.

The Inflammatory Feed-Forward Loop Triggered by the Complement Component C3 as a Potential Target in Endometriosis

The complement system is a major component of humoral innate immunity, acting as a first line of defense against microbes via opsonization and lysis of pathogens. However, novel roles of the complement system in inflammatory and immunological processes, including in cancer, are emerging. Endometriosis (EM), a benign disease characterized by ectopic endometrial implants, shows certain unique features of cancer, such as the capacity to invade surrounding tissues, and in severe cases, metastatic properties. A defective immune surveillance against autologous tissue deposited in the peritoneal cavity allows immune escape for endometriotic lesions. There is evidence that the glandular epithelial cells found in endometriotic implants produce and secrete the complement component C3. Here, we show, using immunofluorescence and RT-qPCR, the presence of locally synthesized C3 in the ectopic endometriotic tissue, but not in the eutopic tissue. We generated a murine model of EM via injection of minced uterine tissue from a donor mouse into the peritoneum of recipient mice. The wild type mice showed greater amount of cyst formation in the peritoneum compared to C3 knock-out mice. Peritoneal washings from the wild type mice with EM showed more degranulated mast cells compared to C3 knock-out mice, consistent with higher C3a levels in the peritoneal fluid of EM patients. We provide evidence that C3a participates in an auto-amplifying loop leading to mast cell infiltration and activation, which is pathogenic in EM. Thus, C3 can be considered a marker of EM and its local synthesis can promote the engraftment of the endometriotic cysts.

The role of alpha lipoic acid in female and male infertility: a systematic review

OBJECTIVE

Infertility is an increasingly frequent health condition, which may depend on female or male factors. Oxidative stress (OS), resulting from a disrupted balance between reactive oxygen species (ROS) and protective antioxidants, affects the reproductive lifespan of men and women. In this review, we examine if alpha lipoic acid (ALA), among the oral supplements currently in use, has an evidence-based beneficial role in the context of female and male infertility.

METHODS

We performed a search from English literature using PubMed database with the following keywords: 'female infertility', 'male infertility', 'semen', 'sperm', 'sub-fertile man', 'alpha-lipoic acid', ' alpha lipoic acid', 'lipoid acid', 'endometriosis', 'chronic pelvic pain', 'follicular fluid' and 'oocytes'. We included clinical trials, multicentric studies and reviews. The total number of references found after automatically and manually excluding duplicates was 180. After primary and secondary screening, 28 articles were selected.

RESULTS

The available literature demonstrates the positive effects of ALA in multiple processes from oocyte maturation (0.87 ± 0.9% of oocyte in MII vs 0.81 ± 3.9%; p < .05) to fertilization, embryo development (57.7% vs 75.7% grade 1 embryo; p < .05) and reproductive outcomes. Its regular administration both in sub-fertile women and men shows to reduce pelvic pain in endometriosis (p < .05), regularize menstrual flow and metabolic disorders (p < .01) and improve sperm quality (p < .001).

CONCLUSIONS

ALA represents a promising new molecule in the field of couple infertility. More clinical studies are needed in order to enhance its use in clinical practice.

Overview of miRNAs for the non-invasive diagnosis of endometriosis: evidence, challenges and strategies. A systematic review

OBJECTIVE

The aim of the study was to assess the evidence on miRNAs as biomarkers for the diagnosis of endometriosis, as well as to provide insights into the challenges and strategies associated with the use of these molecules as accessible tools in clinical practice.

METHODS

Systematic review conducted on PubMed®, Latin American and Caribbean Health Sciences Literature (LILACS), MEDLINE® and Web of Science databases using the search terms endometriosis (all fields) AND miRNA (all fields), evaluating all publication up to May 2019.

RESULTS

Most miRNAs found to be dysregulated in this study were harvested from tissue samples, which precludes their use as a non-invasive diagnostic test. However, differential expression of 62 miRNAs was reported in samples that may be used for non-invasive diagnosis of endometriosis, such as blood, serum and plasma.

CONCLUSION

Despite the identification of several candidates, studies are investigatory in nature and have been conducted with small number of samples. Also, no particular miRNA has been validated for diagnostic purposes so far. Studies based primarily on biological samples and applicable to translational research are warranted. Large databases comprising information on sample type and the use of saliva and vaginal fluid for miRNAs identification may prove essential to overcome current barriers to diagnosis of endometriosis.

Endometriosis stromal cells induce bone marrow mesenchymal stem cell differentiation and PD-1 expression through paracrine signaling

Endometriosis is an estrogen-dependent, inflammatory gynecological disorder characterized by the growth of endometrial cells in lesions outside the uterus. Bone marrow-derived cells (BMDCs) engraft lesions and increase lesion size. Do endometriosis cells regulate differentiation of engrafted BMDCs in the pathogenesis and growth of endometriosis? Here, we report endometriosis derived stromal cells promote the differentiation of BMDCs to stromal, epithelial and leukocyte cell fates through paracrine signaling. In-vitro studies demonstrated that both mRNA and protein levels of vimentin, cytokeratin and PD-1 were significantly increased in BMDCs cocultured with stromal cells from endometriosis (ENDO) patients compared to stromal cells from normal endometrium (CNTL). Increased expression of PD-1 has been reported in malignancy where it promotes T cell quiescence and immune tolerance. Increased PD-1 was also confirmed in-vivo where we showed that PD-1 expression was induced in BMDCs engrafted into endometriotic lesions in a murine model of endometriosis. AMD3100, an antagonist for CXCR4 receptor inhibited PD-1 expression in BMDCs suggesting that PD-1 induction requires CXCL12. These results suggest that endometriosis stimulated BMDC differentiation through paracrine signaling and increased T cell PD-1 expression. Increased PD-1 expression may be one mechanism by which endometriosis avoids immune surveillance.

Alpha-lipoic acid improves the reproduction performance of breeder hens during the late egg-laying period

Alpha-lipoic acid (ALA), a multifunctional antioxidant, can promote fatty acid mobilization, energy expenditure and scavenge free radicals. The effects of dietary ALA on the reproductive performance of breeder hens were investigated in the current study. In the 5-week experiment, 180 54-week-old Qiling breeder hens were randomly divided into three treatments with five replicates and supplemented with three levels of ALA (0, 300 and 600 mg/kg) in the basic corn-soya bean meal diets. 600 mg/kg ALA treatment group (HLA) significantly improved the eggshell thickness and strength (p < .05). ALA-treated groups improved egg-laying rate compared with the CON group, but with no statistically significant difference (p > .05). The levels of HDL-C, ALB and estradiol (E2) of the serum in the HLA group were elevated compared with the CON group (p < .05). In addition, ALA (600 mg/kg) treatment exhibited a reduced level of serum AST and TG (p < .05). Dietary ALA increased the activity of hepatic lipase in liver (p < .05). Supplemental 600 mg/kg ALA also improved the SOD activity and total antioxidant capacity level, along with a decreased MDA in ovarian tissue (p < .05). Furthermore, the mRNA expressions of ESR1, ESR2, VTG2 and ApoB in the liver and FSHR in follicles were upregulated in the HLA group (p < .05). In conclusion, dietary supplementation with 600 mg/kg ALA during the late egg-laying period could improve lipid metabolism and reproductive performance of breeder hens.

The role of honeybee pollen as a natural source of antioxidants in the in vitro maturation medium of sheep oocytes and its effect on gene expression

This study aimed to investigate the effect of honeybee pollen as an antioxidant source in a maturation medium of sheep oocytes on the in vitro maturation rate, glutathione concentration, and gene expression. To our knowledge, this study might be the first of its kind in this field. Sheep oocytes were cultured in vitro with honeybee pollen at four different concentrations (0.0, 1.0, 10.0, and 50.0 μg/ml). The results indicated that the ratio of oocytes that reached metaphase II stage was higher in the honeybee pollen-treated groups than in the control group (p ≤ 0.05). The reduced glutathione (GSH) mean content of matured oocytes was 9.85 nmol/25 oocytes, when honeybee pollen was added to the in vitro maturation (IVM) medium at a concentration of 1.0 μg/ml, compared with 5.84 and 4.44 nmol when using 10.0 and 50.0 μg/ml honeybee pollen, respectively. On the other hand, there was no significant difference in glutathione concentration between the control and 1.0 μg/ml honeybee pollen groups. Expression of candidate genes (GDF-9, BAX, Cyclin B, C-MOS, and IGF1) was upregulated in oocytes cultured with honeybee pollen when compared with oocytes cultured without honeybee pollen. In conclusion, the addition of honeybee pollen at a concentration of 1.0 μg/ml to IVM medium improved the in vitro maturation rate of sheep oocytes, increased the glutathione concentration, and improved gene expression.

Endometriosis: current challenges in modeling a multifactorial disease of unknown etiology

Endometriosis is a chronic inflammatory hormone-dependent condition associated with pelvic pain and infertility, characterized by the growth of ectopic endometrium outside the uterus. Given its still unknown etiology, treatments usually aim at diminishing pain and/or achieving pregnancy. Despite some progress in defining mode-of-action for drug development, the lack of reliable animal models indicates that novel approaches are required. The difficulties inherent to modeling endometriosis are related to its multifactorial nature, a condition that hinders the recreation of its pathology and the identification of clinically relevant metrics to assess drug efficacy. In this review, we report and comment endometriosis models and how they have led to new therapies. We envision a roadmap for endometriosis research, integrating Artificial Intelligence, three-dimensional cultures and organ-on-chip models as ways to achieve better understanding of physiopathological features and better tailored effective treatments.

The Effect of Rutin and Extracts of Uncaria guianensis (Aubl.) J. F. Gmeland on Primary Endometriotic Cells: A 2D and 3D Study

There is increasing interest in the potential of natural compounds to treat diseases, such as endometriosis, a gynecological disorder that affects 10–15% of women of reproductive age, and it is related to severe pelvic pain and infertility. We have evaluated the in vitro effects of rutin and the aqueous bark, roots, and leaf extracts (ABE, ARE, and ALE, respectively) and isolated components of Uncaria guianensis on stromal cells from eutopic endometrium and lesions of patients with endometriosis. Two- and three-dimensional cultures were used to assess the cell death and production of reactive oxygen species (ROS), cytokines and growth factors of cells following exposure to these natural products. The applied treatments did not reduce cellular viability, but ROS production did increase. In addition, significant increases in the levels of interleukin (IL)-15, IL-17A, IL-4, IL-6, tumor necrosis factor-α, and vascular endothelium growth factor were observed when 2D-cells from endometrium of patients with endometriosis were treated with ABE, while exposure to ALE induced significant increases in epidermal growth factor in lesion cells.

The Increase of Circulating PD-1- and PD-L1-Expressing Lymphocytes in Endometriosis: Correlation with Clinical and Laboratory Parameters

The cause of endometriosis remains unknown. However, studies investigating the link between this condition and the immune system revealed several immunological abnormalities focused on cell-mediated immunity. As a major immune checkpoint, programmed cell death protein 1 (PD-1) displays an important inhibitory function in the maintenance of peripheral tolerance. The expression of PD-1 and its ligand (PD-L1) may contribute to continuous T cell activation and development of inflammation and injury of the tissue. To our knowledge, this is the first study evaluating frequencies of PD-1-positive T CD3⁺ cells (CD4⁺ and CD8⁺) and B cells (CD19⁺) in patients with endometriosis. Peripheral blood (PB) samples from 25 female patients and 20 healthy age and sex-matched subjects serving as controls were used in the study. Using flow cytometric analysis, we assessed the differences in the frequencies of PD-1-positive T and B lymphocytes in the study group and healthy individuals. Alteration of the PD-1/PD-L1 axis may contribute to the pathogenesis of endometriosis, as patients with advanced disease are characterized by higher frequencies of PD-1-positive T and B cells. Expression of PD-1 and PD-L1 on T and B cells could represent the hallmark of immune system reaction to chronic antigenic exposition in patients with endometriosis.

Alpha lipoic acid in obstetrics and gynecology

Alpha-Lipoic acid (ALA) is a natural antioxidant synthetized by plants and animals, identified as a catalytic agent for oxidative decarboxylation of pyruvate and α-ketoglutarate. In this review, we analyzed the action of ALA in gynecology and obstetrics focusing in particular on neuropathic pain and antioxidant and anti-inflammatory action. A comprehensive literature search was performed in PubMed and Cochrane Library for retrieving articles in English language on the antioxidant and anti-inflammatory effects of ALA in gynecological and obstetrical conditions. ALA reduces oxidative stress and insulin resistance in women with polycystic ovary syndrome (PCOS). The association of N-acetyl cysteine (NAC), alpha-lipoic acid (ALA), and bromelain (Br) is used for prevention and treatment of endometriosis. In association with omega-3 polyunsaturated fatty acids (n-3 PUFAs) with amitriptyline is used for treatment of vestibulodynia/painful bladder syndrome (VBD/PBS). A promising area of research is ALA supplementation in patients with threatened miscarriage to improve the subchorionic hematoma resorption. Furthermore, ALA could be used in prevention of diabetic embryopathy and premature rupture of fetal membranes induced by inflamation. In conclusion, ALA can be safely used for treatment of neuropatic pain and as a dietary support during pregnancy.

Effectiveness of an antioxidant preparation with N-acetyl cysteine, alpha lipoic acid and bromelain in the treatment of endometriosis-associated pelvic pain: LEAP study

OBJECTIVE

To assess the impact of an antioxidant preparation with N-acetyl cysteine, alpha lipoic acid and bromelain on endometriosis-associated pelvic pain.

STUDY DESIGN

Multicenter, open-label, non-comparative clinical trial in a representative sample of women with endometriosis-associated pelvic pain.

RESULTS

In total, 398 patients with a mean age of 34.6 ± 7.2 years were treated with a combination of N-acetyl cysteine, alpha lipoic acid and bromelain for 6 months. At baseline, 92.7% of the patients had pain intensity > 4 on the visual analogue scale (VAS); at 3 months of treatment, this percentage decreased to 87.2% (p = 0.074) and at 6 months the percentage was 82.7% (p < 0.05).

CONCLUSIONS

Women with endometriosis who wish to become pregnant and are treated with a preparation containing N-acetyl cysteine, alpha lipoic acid and bromelain experienced a significant improvement in endometriosis-associated pelvic pain and required lower intake of rescue analgesics.

Endometriosis Is a Cause of Infertility. Does Reactive Oxygen Damage to Gametes and Embryos Play a Key Role in the Pathogenesis of Infertility Caused by Endometriosis?

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.

Regulation of apoptotic pathways during endometriosis: from the molecular basis to the future perspectives

PURPOSE

Endometriosis is defined as the presence of endometrial-like endometrial cells, glands and stroma outside the uterus, causing a strong inflammatory-like microenvironment in the affected tissue. This may provoke a breakdown in the peritoneal cavity homeostasis, with the consequent processes of immune alteration, documented by peripheral mononuclear cells recruitment and secretion of inflammatory cytokines in early phases and of angiogenic and fibrogenic cytokines in the late stages of the disease. Considering the pivotal role of interaction between immune and endometriotic cells, in this paper, we aim to shed light about the role of apoptosis pathways in modulating the fine-regulated peritoneal microenvironment during endometriosis.

METHODS

Narrative overview, synthesizing the findings of literature retrieved from searches of computerized databases.

RESULTS

In normal conditions, endometriotic cells, refluxed through the fallopian tubes into the peritoneal cavity, should be attacked and removed by phagocytes and NK cells. During endometriosis, the breakdown of peritoneal homeostasis causes the failure of scavenging mechanisms, allowing the survival of endometriotic cells. The consequent so-called "immunoescaping" of endometriotic cells could be due, at least in part, to the reduction of apoptotic-mediated pathways previously described.

CONCLUSION

Considering the large amount of evidence retrieved from in vitro as well as in vivo models, the reduced apoptosis of endometriotic cells together with the increased apoptosis of peritoneal fluid mononuclear cells may address the peritoneal homeostasis to a permissive environment for the progression of the disease.