Vitamin C is effective for the prevention and regression of endometriotic implants in an experimentally induced rat model of endometriosis

Oxidative Imbalance in Endometriosis-Related Infertility-The Therapeutic Role of Antioxidants

Endometriosis in half of affected women is closely related to problems with fertility. Endometriosis-associated infertility is caused by a wide range of abnormalities affecting the female reproductive tract, from oocyte quality impairment to disturbances in the eutopic endometrium or mechanical abnormalities resulting from disease progression. Since supportive antioxidant therapies, in addition to surgical treatment or assisted reproductive techniques (ARTs), have overall been proven to be effective tools in endometriosis management, the objective of our review was to analyze the role of antioxidant substances, including vitamins, micronutrients, N-acetylcysteine (NAC), curcumin, melatonin, and resveratrol, in endometriosis-related infertility. Most of these substances have been proven to alleviate the systemic oxidant predominance, which has been expressed through decreased oxidative stress (OS) markers and enhanced antioxidative defense. In addition, we demonstrated that the predominant effect of the aforementioned substances is the inhibition of the development of endometriotic lesions as well as the suppression of pro-inflammatory molecules. Although we can undoubtedly conclude that antioxidants are beneficial in fertility support, further studies explaining the detailed pathways of their action are needed.

Ferroptosis and oxidative stress in endometriosis: A systematic review of the literature

BACKGROUND

Endometriosis (EMT) a common gynecological condition in women, an inflammatory disease characterized by the presence of endometrial tissue on organs and tissues in the pelvis, and is mainly associated with chronic pelvic pain and infertility. As the etiology has not been fully elucidated, current treatment is limited to surgery, hormones and painkillers, with more side effects and difficulty in achieving long-term relief. Oxidative stress manifests itself as an overproduction of reactive oxygen species, which has an integral impact in the pathology of female reproductive disorders. In this review, we evaluate the mechanisms of iron overload-induced oxidative stress and ferroptosis in EMT and their pathophysiological implications.

METHODS

Because the etiology has not been fully elucidated, current treatments are limited to surgery, hormones, and painkillers, which have many side effects and are difficult to achieve long-term relief.

RESULTS

We interpreted that antioxidants as well as ferroptosis inducers show promising results in the treatment of EMT, but their application in this population needs to be further investigated.

CONCLUSION

In combination with the interpretation of previous studies, it was shown that iron overload is present in the peritoneal fluid, endometriotic lesions, peritoneum and macrophages in the abdominal cavity. However, the programmed cellular ferroptosis associated with iron overload is resisted by endometriotic foci, which is critical to the pathophysiology of EMT with local iron overload and inflammation.

How Can Selected Dietary Ingredients Influence the Development and Progression of Endometriosis?

Endometriosis is a chronic, hormone-dependent disease characterized by the presence of endometrial tissue in ectopic locations. Since the treatment options for this disease are still limited, and the cure rate is unsatisfactory, the search for ways to treat symptoms and modify the course of the disease is of key importance in improving the quality of life of patients with endometriosis. So far, the literature has shown that nutrition can influence endometriosis through hormonal modification and altering the inflammatory or oxidative response. Since the importance of nutrition in this disease is still a subject of scientific research, we aimed to summarize the current knowledge on the role of dietary modifications in endometriosis. Our review showed that nutrients with anti-inflammatory and antioxidant properties, including most vitamins and several trace elements, may influence the pathogenesis of endometriosis and can be considered as the nutrients preventing the development of endometriosis. However, despite the many discoveries described in this review, further interdisciplinary research on this topic seems to be extremely important, as in the future, it may result in the development of personalized therapies supporting the treatment of endometriosis.

Antioxidant vitamins supplementation reduce endometriosis related pelvic pain in humans: a systematic review and meta-analysis

OBJECTIVE

This study aimed to clarify the effect of antioxidant vitamins supplementation on endometriosis-related pain.

METHODS

A systematic search of PubMed, Web of Science, Cochrane Library, Scopus, and China National Knowledge Infrastructure (CNK) databases was conducted to identify relevant studies published in English and Chinese up to 16 March 2023. The search terms used were "endometriosis" OR "endometrioma" OR "endometrium" AND "antioxidant" OR "Vitamin C" OR "Vitamin E" OR "Vitamin D" OR "25-OHD" OR "25(OH)D" OR "25-hydroxyvitamin D". Eligible studies were randomized controlled trials (RCTs) that assessed pain scores using the Visual Analogue Scale (VAS). Mean differences or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the effect of antioxidant vitamins supplementation on endometriosis. The quality of the included studies was assessed using the Cochrane Risk of Bias Tool. The study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines.

RESULTS

A total of 13 RCTs involving 589 patients were included in this meta-analysis. We identified 11 studies that evaluated the effect of antioxidant vitamins supplementation on endometriosis-related pain. The results indicated that the supplementation of antioxidant vitamins can effectively alleviate endometriosis-related pain. Subgroup analysis showed that the supplementation of vitamin E (with or without vitamin C) had a positive effect on improving clinical pelvic pain in patients with chronic pelvic pain. Conversely, supplementation of vitamin D was associated with a reduction in pelvic pain in endometriosis patients, but the difference was not statistically significant compared to the placebo. Additionally, we observed changes in oxidative stress markers following vitamin supplementation. Plasma malondialdehyde (MDA) concentration decreased in patients with endometriosis after antioxidant vitamin supplementation, and the plasma MDA level was inversely correlated with the time and dose of vitamin E and C supplementation. Furthermore, the inflammatory markers in peritoneal fluid, including RANTES, interleukin-6, and monocyte chemoattractant protein-1, significantly decreased after antioxidant therapy. These findings suggest that antioxidant vitamins may alleviate pain in endometriosis patients by reducing inflammation.

CONCLUSIONS

The included studies support the potential role of antioxidant vitamins in the management of endometriosis. Supplementation with antioxidant vitamins effectively reduced the severity of dysmenorrhea, improved dyspareunia and pelvic pain, and enhanced quality of life in these patients. Therefore, antioxidant vitamin therapy could be considered as an alternative treatment method, either alone or in combination with other approaches, for endometriosis-related pain.

TRIAL REGISTRATION

PROSPERO registration number: CRD42023415198.

The relationship between endometriosis and diet

Endometriosis is an oestrogen dependent, benign, chronic inflammatory disease characterised by ectopic endometrial implants. Current medical practices for the treatment of the disease are associated with several side effects over long periods, making the effect of diet on endometriosis an important aspect. To alleviate this need, we review related literature to identify the association between nutrients and endometriosis and to find the probable therapeutic effects of the nutrients and foods on endometriosis. Despite variations among the findings, several of the prior studies point to an inverse relationship between endometriosis and the consumption of fruits, vegetables, dairy products, and omega-3 fatty acids. Another common finding among the studies is the increased risk of endometriosis with higher consumption of trans-unsaturated fatty acids and red meat. Due to the limited size of the samples in existing literature, however, significance of the association between diet and endometriosis is not conclusive. Further research is needed to better identify the role of diet on endometriosis.

The Role of Selected Dietary Factors in the Development and Course of Endometriosis

Endometriosis is a chronic disease with a complex, heterogeneous pathogenesis that affects about 10% of women of reproductive age, causing pain and leading to infertility. Treatment consists of administering pharmacological agents (resulting in a reduction of estrogen levels and inflammation), as well as the surgical removal of endometriotic lesions. Unfortunately, despite a wide range of available therapies, there is still a high recurrence rate after surgery. Consequently, it is necessary to improve the outcome of patients with endometriosis. In this context, there is growing interest in possible dietary modification to support or complement classic treatment options and even serve as a potential alternative to hormone therapy. In addition, a growing number of studies indicate positive effects of selected dietary factors on the development and course of endometriosis. This review article focuses on the potentially beneficial effects of compounds from the polyphenol group (curcumin, epigallocatechin gallate, quercetin, resveratrol), vitamins, and selected micronutrients on endometriosis. The results indicate the potential of the selected ingredients in fighting the disease. However, most of the studies have been performed on experimental animal models, with a smaller proportion looking at the actual effects of use among women. Therefore, well-designed studies are needed to assess the importance of a well-chosen diet and the effects of specific dietary factors on the health of women suffering from endometriosis.

Emerging hallmarks of endometriosis metabolism: A promising target for the treatment of endometriosis

Endometriosis, characterized by ectopic endometrium growth in the extrauterine environment, is one of the most notable diseases of the female reproductive system. Worldwide, endometriosis affects nearly 10 % of women in their reproductive years and causes a significant decline in quality of life. Despite extensive investigations of endometriosis over the past years, the mechanisms of endometriosis pathogenesis remain unclear. In recent years, metabolic factors have increasingly been considered factors in endometriosis. There is compelling evidence regarding the progress of endometriosis in the context of severe metabolic dysfunction. Hence, the curative strategies and ongoing attempts to conquer endometriosis might start with metabolic pathways. This review focuses on metabolic mechanisms and summarizes current research progress. These findings provide valuable information for the non-intrusive diagnosis of the disease and may contribute to the understanding of the pathogenesis of endometriosis.

The effectiveness of antioxidant therapy (vitamin C) in an experimentally induced mouse model of ovarian endometriosis

Objectives:

This study investigates the therapeutic effect of vitamin C on the development of endometrial lesions and fecundity disorders in the ovarian induction model of mouse endometriosis.

Methods:

Ovarian endometriosis was surgically induced in 14 NMRI female mice (treatment group, N = 7) and (control group, N = 7). Three days after the second surgery (to assess endometriotic implant), the mice were randomized into two intervention groups: control (placebo) and treatment (50 mg/kg vitamin C every two days orally for four weeks) groups. In the oestrus phase, the mice were sacrificed. In macroscopic assessment, endometriotic implants were evaluated in size, volume, weight, growth score and adhesion score. The microscopic assessment examined the ovarian tissue (the number of antral follicles, corpus luteum and atretic follicles) and endometriotic lesion (histologic and trichrome fibrosis scores).

Results:

Post-treatment implant volume, growth score, adhesion extent score and adhesion severity score were significantly lower in the treatment group (vitamin C) in comparison with the control group (placebo) (p < 0.0001). The difference between the median weight of endometriotic implants, epithelialization of implant tissue, trichrome fibrosis scores and follicle number in the two groups (treatment and control) was statistically significant (p < 0.05). Atretic follicles were significantly decreased after vitamin C therapy (p < 0.05). Although the numbers of corpus luteum seemed to be more preserved in specimens from the control group, there was no statistical significance between the two groups’ histological scores.

Conclusion:

As a result, we may imply that vitamin C has a significant effect on reducing the induction and growth of endometrial implants, improving the fecundity function of ovaries, and consequently prevention of endometriosis-associated cancers. Further research is needed to improve targeted interventions resulting in the prevention and treatment of human endometriosis.

The Effect of Combined Vitamin C and Vitamin E Supplementation on Oxidative Stress Markers in Women with Endometriosis: A Randomized, Triple-Blind Placebo-Controlled Clinical Trial

Background

Endometriosis is a chronic and estrogen-dependent pelvic inflammatory disease, which may have various causes, such as oxidative stress. Dysmenorrhea, dyspareunia, and pelvic pain are well-known symptoms of endometriosis. The present clinical trial assessed the role of supplementation with antioxidant vitamins on the indices of oxidative stress as well as the severity of pain in women with endometriosis.

Materials and Methods

We enrolled 60 reproductive-aged (15–45 years) women with pelvic pain in this triple-blind clinical trial. They had 1–3 stages of laparoscopic-proven endometriosis. The participants were randomized to group A (n = 30), given vitamin C (1000 mg/day, 2 tablets of 500 mg each) and vitamin E (800 IU/day, 2 tablets of 400 IU each) combination, or group B (n = 30), given placebo pills daily for 8 weeks.

Results

Following treatment with vitamin C and vitamin E, we found a significant reduction in MDA and ROS compared with the placebo group. There was no significant decline in total antioxidant capacity after treatment. However, the severity of pelvic pain (p value <0.001), dysmenorrhea (p value <0.001), and dyspareunia (p value <0.001) significantly decreased in the treatment group after 8 weeks of supplementation.

Conclusions

The present findings support the potential role of antioxidants in the management of endometriosis. The intake of vitamin C and vitamin E supplements effectively reduced dysmenorrhea severity and improved dyspareunia and severity of pelvic pain.

Ameliorating Effects of Natural Antioxidant Compounds on Female Infertility: a Review

The prevalence of female infertility cases has been increasing at a frightening rate, affecting approximately 48 million women across the world. However, oxidative stress has been recognized as one of the main mediators of female infertility by causing various reproductive pathologies in females such as endometriosis, PCOS, preeclampsia, spontaneous abortion, and unexplained infertility. Nowadays, concerned women prefer dietary supplements with antioxidant properties over synthetic drugs as a natural way to lessen the oxidative stress and enhance their fertility. Therefore, the current review is an attempt to explore the efficacy of various natural antioxidant compounds including vitamins, carotenoids, and plant polyphenols and also of some medicinal plants in improving the fertility status of females. Our summarization of recent findings in the current article would pave the way toward the development of new possible antioxidant therapy to treat infertility in females. Natural antioxidant compounds found in fruits, vegetables, and other dietary sources, alone or in combination with other antioxidants, were found to be effective in ameliorating the oxidative stress-mediated infertility problems in both natural and assisted reproductive settings. Numerous medicinal plants showed promising results in averting the various reproductive disorders associated with female infertility, suggesting a plant-based herbal medicine to treat infertility. Although optimum levels of natural antioxidants have shown favorable results, however, their excessive intake may have adverse health impacts. Therefore, larger well-designed, dose-response studies in humans are further warranted to incorporate natural antioxidant compounds into the clinical management of female infertility.

MiR-210-3p protects endometriotic cells from oxidative stress-induced cell cycle arrest by targeting BARD1

Endometriosis is associated with benign but adversely developed cysts in the extrauterine environment. The oxidative imbalanced environment induces DNA damage and affects cell cycle progression of endometrial stromal cells (ESCs) and endometrial epithelial cells, but how endometriotic cells maintain proliferation in the presence of oxidative stress is not clear. Growing evidence has indicated that the ectopic hypoxic microenvironment and oxidative stress can stimulate the growth of endometriotic cells, which is mainly due to the increase of HIF-1α. We found that the master hypoxia-associated miRNA miR-210-3p was increased in stromal and glandular cells of ectopic lesions compared with that of eutopic and normal endometria and was consistent with the expression of HIF-1α and the local oxidative stress-induced DNA damage predictor 8-OHdG. Moreover, miR-210-3p was upregulated in ESCs and Ishikawa cells under hypoxic conditions but not in normoxic culture. Knockdown of miR-210-3p induced a G2/M arrest of ESCs and Ishikawa cells under hypoxia, while no effect was found under normoxia. BARD1 was identified as a target of miR-210-3p. BARD1 expression was decreased in endometriotic tissues compared with eutopic and normal endometria and negatively correlated with the expression of miR-210-3p. Multivariate regression analysis showed that BARD1 downregulation could serve as an indicator for endometriotic severity. Our results suggest that miR-210-3p attenuates the G2/M cell cycle checkpoint by inactivating BRCA1 complex function in response to DNA damage under hypoxia via targeting the 3′ untranslated region of BARD1 mRNA. Endometriotic mouse model experiments showed that intraperitoneal injection of the miR-210-3p inhibitor or vitamin C suppressed the growth of endometriotic lesions. Together, our results demonstrate that endometriotic cells inhibit BARD1/BRCA1 function by upregulating miR-210-3p, which might be the underlying mechanism for endometriotic cell maintenance of growth in oxidative stress. Furthermore, inhibition of miR-210-3p and administration of vitamin C are promising approaches for the treatment of endometriosis.

Effects of vitamin C on the outcome of in vitro fertilization-embryo transfer in endometriosis: A randomized controlled study

OBJECTIVE

This study was performed to investigate the effect of vitamin C (VitC) supplementation on the outcomes of in vitro fertilization-embryo transfer (IVF-ET) in patients with endometriosis (EMs).

METHODS

A total of 280 patients with EMs underwent IVF-ET (VitC treatment group, n=160; VitC non-treatment group, n=120). An additional 150 patients who did not have EMs but underwent IVF-ET (control group) were also enrolled in this study. Superoxide dismutase (SOD), total antioxidant capacity (TAC), malondialdehyde (MDA) and reactive oxygen species (ROS) were measured to determine the role of VitC on oxidative stress markers in serum and follicular fluid (FF).

RESULTS

In total, 245 patients with EMs and 132 patients without EMs underwent successful IVF-ET and follow-up. The serum or FF levels of VitC, SOD, and TAC were lower in the EMs than control group; however, the MDA and ROS levels in serum or FF were higher in the EMs than control group. After 2 months of VitC treatment, the serum VitC levels in serum and FF were significantly increased, while oxidative stress markers were unaffected.

CONCLUSION

Treatment with VitC oral formulation improved the serum and FF levels of VitC but did not affect oxidative stress markers in patients with EMs.

Establishment of an in ovo chick embryo yolk sac membrane (YSM) assay for pilot screening of potential angiogenic and anti-angiogenic agents

Angiogenesis, the process of new blood vessel formation from pre-existing vessels, is essential for growth and development. Development of drugs that can accelerate or decelerate angiogenesis in the context of various diseases requires appropriate preclinical screening. As angiogenesis involves complex cellular and molecular processes, in vivo studies are superior to in vitro investigations. Conventional in vitro, in vivo, and ex ovo models of angiogenesis are time consuming and tedious, and require sophisticated infrastructure for embryo culture. In the present study, we established an in ovo chick embryo yolk sac membrane (YSM) assay for angiogenesis and tested the angiogenic potential of arginine, conditioned medium (CM) from human adipose tissue and placenta-derived mesenchymal stem cells (ADMSCs-CM and PDMSCs-CM), avastin and vitamin C. The obtained results were confirmed with the routinely employed chick embryo Chorioallantoic Membrane (CAM) assay. Both assays revealed the pro-angiogenic nature of arginine, ADMSCs-CM, and PDMSCs-CM, and the anti-angiogenic effect of avastin and vitamin C. This novel in ovo YSM model is simple, reproducible, and highly economic in terms of the time frame and cost incurred. The proposed model is thus a suitable substitute to the CAM model for pilot screening of potential angiogenic and anti-angiogenic agents.

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.