Effects of anti-TNF-mAb treatment on pregnancy in baboons with induced endometriosis

The Known, the Unknown and the Future of the Pathophysiology of Endometriosis

Endometriosis is one of the most common causes of chronic pelvic pain and infertility, affecting 10% of women of reproductive age. A delay of up to 9 years is estimated between the onset of symptoms and the diagnosis of endometriosis. Endometriosis is currently defined as the presence of endometrial epithelial and stromal cells at ectopic sites; however, advances in research on endometriosis have some authors believing that endometriosis should be re-defined as "a fibrotic condition in which endometrial stroma and epithelium can be identified". There are several theories on the etiology of the disease, but the origin of endometriosis remains unclear. This review addresses the role of microRNAs (miRNAs), which are naturally occurring post-transcriptional regulatory molecules, in endometriotic lesion development, the inflammatory environment within the peritoneal cavity, including the role that cytokines play during the development of the disease, and how animal models have helped in our understanding of the pathology of this enigmatic disease.

Novel therapeutic targets to improve IVF outcomes in endometriosis patients: a review and future prospects

BACKGROUND

Patients with endometriosis often experience infertility and have poor IVF outcomes, with low fertilization and pregnancy rates. Although many theories have tried to explain the mechanisms underlying infertility in these patients, none of them is conclusive.

OBJECTIVE AND RATIONALE

In this review, we discuss the pathologic mechanisms through which endometriosis likely leads to infertility along with the therapeutic options used to date to treat endometriosis-related infertility and, thereby, to improve IVF outcomes in patients with endometriosis.

SEARCH METHODS

We performed a comprehensive literature search of clinical outcomes in endometriosis and the molecular mechanisms contributing to oocyte quality using the PubMed database to identify human and animal studies published from 1992 until September 2020. In total, 123 manuscripts were included.

OUTCOMES

While some theories propose that endometriosis patients may have fertility problems as a result of decreased endometrial receptivity, others reinforce the idea that infertility could be associated with oocyte alterations and lower implantation rates. Single-cell RNA sequencing of oocytes from patients with endometriosis has identified dysregulated mechanisms involved in steroid metabolism and biosynthesis, response to oxidative stress and cell cycle regulation. Dysregulation of these mechanisms could result in the poor IVF outcomes observed in patients with endometriosis. Further, impaired steroidogenesis may directly affect oocyte and embryo quality. Increased oxidative stress in patients with endometriosis also has a detrimental effect on the follicular microenvironment, inducing cell cycle dysregulation in oocytes, poor oocyte quality, and infertility. Moreover, granulosa cells in the context of endometriosis undergo increased apoptosis and have an altered cell cycle that could adversely affect folliculogenesis, oocyte and embryo quality, and IVF outcomes. Endometriosis is also associated with inflammatory damage and impaired angiogenesis, which could be directly correlated with poor IVF outcomes. While therapeutic options using GnRH analogues, progestins and aromatase inhibitors do not improve endometriosis-related infertility, anti-inflammatory agents and antioxidant supplementation could improve oocyte quality as well as implantation and clinical pregnancy rates in patients with endometriosis.

WIDER IMPLICATIONS

Endometriosis is a heterogeneous disease whose pathogenesis is complex and could affect fertility by altering a collection of molecular mechanisms in oocytes. Thus, a single model is not sufficient to describe endometriosis-related infertility. Dysregulation of steroidogenesis, oxidative stress, cell cycle progression, inflammation and angiogenesis in the follicular environment and oocytes in individuals with endometriosis are all possible contributors to endometriosis-related infertility. Therefore, treatments targeting these mechanisms could be therapeutic alternatives to improve IVF outcomes for these patients.

Anti-inflammatory cytokines in endometriosis

Although the pathogenesis of endometriosis is not fully understood, it is often considered to be an inflammatory disease. An increasing number of studies suggest that differential expression of anti-inflammatory cytokines (e.g., interleukin-4 and -10, and transforming growth factor-β1) occurs in women with endometriosis, including in serum, peritoneal fluid and ectopic lesions. These anti-inflammatory cytokines also have indispensable roles in the progression of endometriosis, including by promoting survival, growth, invasion, differentiation, angiogenesis, and immune escape of the endometriotic lesions. In this review, we provide an overview of the expression, origin, function and regulation of anti-inflammatory cytokines in endometriosis, with brief discussion and perspectives on their future clinical implications in the diagnosis and therapy of the disease.

Implications of immune dysfunction on endometriosis associated infertility

Endometriosis is a complex, inflammatory disease that affects 6-10% of reproductive-aged women. Almost half of the women with endometriosis experience infertility. Despite the excessive prevalence, the pathogenesis of endometriosis and its associated infertility is unknown and a cure is not available. While many theories have been suggested to link endometriosis and infertility, a consensus among investigators has not emerged. In this extensive review of the literature as well as research from our laboratory, we provide potential insights into the role of immune dysfunction in endometriosis associated infertility. We discuss the implication of the peritoneal inflammatory microenvironment on various factors that contribute to infertility such as hormonal imbalance, oxidative stress and how these could further lead to poor oocyte, sperm and embryo quality, impaired receptivity of the endometrium and implantation failure.

Anti-TNF-α treatment for pelvic pain associated with endometriosis

BACKGROUND

Endometriosis is a chronic, recurring condition that can develop during the reproductive years. It is characterised by the development of endometrial tissue outside the uterine cavity. It is the most common cause of pelvic pain in women. This endometrial tissue development is dependent on oestrogen produced primarily by the ovaries and, therefore, traditional management has focused on suppression of ovarian function. Mounting evidence shows that altered immune function plays a crucial role in the genesis and development of endometriosis. In this review we considered modulation of the inflammation as an alternative approach.

OBJECTIVES

To determine the effectiveness and safety of anti-tumour necrosis factor-α (anti-TNF-α) treatment in the management of endometriosis in premenopausal women.

SEARCH METHODS

For the first publication of this review, we searched for trials in the following databases (from their inception to August 2009): Cochrane Menstrual Disorders and Subfertility Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, CINAHL, and PsycINFO. In addition, we searched all reference lists of included trials and contacted experts in the field in an attempt to locate trials. We reran this search to 3 September 2012 for this update.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing anti-TNF-α drugs with placebo, no treatment, medical treatment, or surgery for pelvic pain associated with endometriosis were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality, and extracted data using data extraction forms. The domains assessed for risk of bias were sequence generation, allocation concealment, blinding, incomplete outcome data, and selective outcome reporting. We used risk ratios (RR) for reporting dichotomous data with 95% confidence intervals (CI), whilst we expressed continuous data as mean differences (MD). We assessed statistical heterogeneity using the I(2) statistic.

MAIN RESULTS

Only one trial involving 21 participants was included. The results showed no evidence of an effect of infliximab, one of the known anti-TNF-α drugs, on pelvic pain reduction using the Biberoglu-Behrman (BB) score (0 to 3 scale) for participants (MD -0.14, 95% CI -0.43 to 0.15), the BB score for clinicians (MD -0.14, 95% CI -0.39 to 0.11), or a visual analogue pain score (VAS, 100 mm scale) (MD -5.60, 95% CI -16.10 to 4.90), or on the use of pain killers (ibuprofen, g/day) (MD -0.10, 95% CI -0.30 to 0.10). There was no evidence of an increase in adverse events in the infliximab group compared with placebo (RR 3.73, 95% CI 0.22 to 63.66). We found no evidence of clinical benefits of infliximab for endometriotic lesions, dysmenorrhoea, dyspareunia, or pelvic tenderness. To date, there is no trial that has reported a cost-effectiveness analysis of anti-TNF-α drugs, or the odds of recurrence.

AUTHORS' CONCLUSIONS

This review was updated in 2012. The results of the original review published in 2010 remain unchanged. There is still not enough evidence to support the use of anti-TNF-α drugs in the management of women with endometriosis for the relief of pelvic pain.

Efeito do anti-TNF-α em implantes endometriais no peritônio de ratas

OBJETIVO: Avaliar o efeito da terapia anti-TNF-α no tratamento de implantes endometriais no peritônio de ratas. MÉTODOS: Os implantes endometrióticos foram induzidos cirurgicamente em 120 ratas Wistar-Albino. Os animais foram aleatoriamente distribuídos em 4 grupos. O grupo C (n=36) recebeu uma injeção intraperitoneal de 0,2ml de solução salina. O grupo L (n=41) recebeu uma injeção subcutânea de 1mg/kg de leuprolide. O grupo I5 (n=20) recebeu uma injeção subcutânea de 5mg/kg de anticorpo monoclonal anti-fator de necrose tumoral (TNF) a (infliximab). O grupo I10 (n=20) recebeu uma injeção subcutânea de 10mg/kg de infliximab. As ratas foram sacrificadas após 21 dias para se avaliar o tamanho dos implantes e a expressão do TNF-α. RESULTADOS: O tratamento com leuprolide promoveu uma redução absoluta na área de superfície do implante comparado com o grupo C (+14mm vs. 0mm; p=0,013) e com o grupo I10 (+14mm vs. +5mm; p=0,018). Da mesma forma, uma redução percentual da area de superfície do implante foi observada comparando o grupo L com o grupo C (+33,3% vs. 0%; p=0,005) e com o grupo I10 (+33,3% vs. +18,3%; p=0,027). O tratamento com infliximab não foi capaz de diminuir a área de superfície do implante comparado com o grupo C. A expressão de TNF-α reduziu nos grupos L, I5 e I10 comparado com o grupo C (505,6µm² vs. 660,5µm² vs. 317,2µm² vs. 2519,3µm², respectivamente; p<0,001). CONCLUSÃO: A terapia anti-TNF-α reduziu a expressão de TNF-α nos implantes endometrióticos mas não reduziu a área de superfície da lesão.

Endometriosis: the role of neuroangiogenesis

Endometriosis is a common cause of pelvic pain and infertility, affecting ∼10% of reproductive-age women. Annual costs for medical and surgical care in the United States exceed $20 billion. The disorder is characterized by implants of endometrial tissue outside the uterine cavity. Endometriotic lesions induce a state of chronic peritoneal inflammation, accompanied by elevated prostaglandin, cytokine, and growth factor concentrations. The current therapy is surgical ablation of ectopic implants and hormones that block the hypothalamic-pituitary-ovarian axis, but these approaches are expensive, carry perioperative risks, or have unpleasant side effects of hypoestrogenism. Recent evidence indicates that ectopic endometriotic implants recruit their own unique neural and vascular supplies through neuroangiogenesis. It is believed that these nascent nerve fibers in endometriosis implants influence dorsal root neurons within the central nervous system, increasing pain perception in patients. We consider the mechanisms and therapeutic implications of neuroangiogenesis in these lesions and propose potential treatments for the control or elimination of endometriosis-associated pain.

Anti-TNF-alpha treatment for pelvic pain associated with endometriosis

BACKGROUND

Endometriosis is a chronic, recurring condition that can develop during the reproductive years. It is characterized by the development of endometrial tissue outside the uterine cavity. It is the most common cause of pelvic pain in women. This endometrial tissue development is dependent on estrogen produced primarily by the ovaries and, therefore, traditional management has focused on suppression of ovarian function. The mounting evidence shows that altered immune function plays a crucial role in the genesis and development of endometriosis. In this review we considered modulating the inflammation as an alternative approach.

OBJECTIVES

To determine the effectiveness and safety of anti-tumour necrosis factor-alpha (anti-TNF-alpha) drugs in the management of pelvic pain associated with endometriosis.

SEARCH STRATEGY

We searched for trials in the following databases (from their inception to August 2009): Cochrane Menstrual Disorders and Subfertility Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, CINAHL, and PsycINFO. In addition, all reference lists of included trials were searched and experts in the field were contacted in an attempt to locate trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing anti-TNF-alpha drugs with placebo, no treatment, medical treatment, or surgery for pelvic pain associated with endometriosis were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality, and extracted data using data extraction forms. The domains assessed for risk of bias were sequence generation, allocation concealment, blinding, incomplete outcome data, and selective outcome reporting. Risk ratios (RR) were used for reporting dichotomous data with 95% confidence intervals (CI), whilst mean differences (MD) were expressed for continuous data. Statistical heterogeneity was assessed using the I(2) statistic.

MAIN RESULTS

Only one trial involving 21 participants was included. Results showed no evidence of an effect of infliximab, one of the known anti-TNF-alpha drugs, on pain reduction using the Biberoglu-Behrman (BB) score for patients (MD -0.15, 95% CI -0.51 to 0.21), the BB score for clinicians (MD -0.15, 95% CI -0.45 to 0.15), the visual analogue pain score (VAS) (MD 11.30, 95% CI -3.00 to 25.60) and the use of pain killers (MD -0.10, 95% CI -0.60 to 0.40). There was no evidence of an increase in adverse events in the infliximab group compared with placebo (RR 3.73, 95% CI 0.22 to 63.66). No evidence of clinical benefits of infliximab was found for endometriotic lesions, dysmenorrhoea, dyspareunia or pelvic tenderness. No trial reported the effects of anti-TNF-alpha drugs using economic evaluations and the odds of recurrence.

AUTHORS' CONCLUSIONS

There is no enough evidence to support the use of anti-TNF-alpha drugs in the management of women with endometriosis for the relief of pelvic pain.

The non-human primate model of endometriosis: research and implications for fecundity

The development of an animal model of endometriosis is crucial for the investigation of disease pathogenesis and therapeutic intervention. These models will enhance our ability to evaluate the causes for the subfertility associated with disease and provide a first-line validation of treatment modulators. Currently rodents and non-human primate models have been developed, but each model has their limitations. The aim of this manuscript is to summarize the current findings and theories on the development of endometriosis and disease progression and the effectiveness of therapeutic targets using the experimental induced model of endometriosis in the baboon (Papio anubis).

A call for more transparency of registered clinical trials on endometriosis

In response to the pressing need for more efficacious and safer therapeutics for endometriosis, there have been numerous reports in the last decade of positive results from animal and in vitro studies of various compounds as potential therapeutics for endometriosis. A handful of these have undergone phase II/III clinical trials. Since the announcement of the International Committee of Medical Journal Editors that mandated registration as a prerequisite for publication, 57 endometriosis-related clinical trials have been registered at ClinicalTrials.gov, an Internet-based public depository for information on drug studies. Among them, 25 are listed as completed, and 2 as suspended. There are 15 completed phase II/III trials, which evaluated the efficacy of various promising compounds. Yet only three of the 15 trials (20%) have published their results. The remaining 12 (80%) studies so far have not published their findings. We argue that this apparent lack of transparency will actually not benefit the trial sponsors or the public, and will ultimately prove detrimental to research efforts attempting to develop more efficacious and safer therapeutics for endometriosis. Thus we call for more transparency of clinical trials on endometriosis.

Anti-TNF-alpha treatment for deep endometriosis-associated pain: a randomized placebo-controlled trial

BACKGROUND

Endometriosis is associated with an inflammatory response. Hence infliximab, an anti-TNF-alpha monoclonal antibody, might relieve pain.

METHODS

A randomized placebo-controlled trial was designed with 21 women with severe pain and a rectovaginal nodule of at least 1 cm. After 1 month of observation, three infusions of infliximab (5 mg/kg) or placebo were given. Surgery was performed 3 months later and follow-up continued for 6 months. The primary end-point was pain (dysmenorrhea, deep dyspareunia and non-menstrual pain) rated at each visit by the clinician and on a daily basis by the patient who in addition scored pain by visual analog pain scale and analgesia intake. Secondary end-points included the volume of the endometriotic nodule, pelvic tenderness and the visual appearance of endometriotic lesions at laparoscopy.

RESULTS

Pain severity decreased during the treatment by 30% in both the placebo (P < 0.001) and infliximab groups (P < 0.001). However, no effect of infliximab was observed for any of the outcome measures. After surgery, pain scores decreased in both groups to less than 20% of the initial value.

CONCLUSIONS

Infliximab appears not to affect pain associated with deep endometriosis. Treatment is associated with an important placebo effect. After surgery, pain decreases to less than 20%. Trials registration number ClinicalTrials.gov: NCT00604864.