Effect of recombinant human TNF–binding protein-1 and GnRH antagonist on mRNA expression of inflammatory cytokines and adhesion and growth factors in endometrium and endometriosis tissues in baboons

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.

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.

Overexpression of TGF-β enhances the migration and invasive ability of ectopic endometrial cells via ERK/MAPK signaling pathway

Endometriosis is a common gynecological disease with manifestations of endometrial-like tissue outside the uterus. Transforming growth factor-β (TGF-β) is known to facilitate a series of biological events in many cells, including migration. However, the roles of TGF-β in endometriosis still remain largely unknown. The aim of the present study was to discover the role of TGF-β1 in endometriosis development and progression and its associated mechanisms. It was demonstrated that the expression of TGF-β1 was significantly elevated in endometriosis in comparison with that in normal tissue. Overexpression of TGF-β increased the proliferation and upregulated proliferating cell nuclear antigen and cyclin D1 in endometrial stromal cells (ESCs). Furthermore, TGF-β overexpression also triggered a series of biological events occurring in ESCs, including cell migration and invasion, and activated the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling pathway. The inhibition of the ERK/MAPK pathway reversed the previous effects of TGF-β overexpression. Collectively, the present results indicate that overexpression of TGF-β enhances the migration and invasion of ectopic ESCs via the ERK/MAPK signaling pathway, providing theoretical evidence for the development of new treatment methods targeting the TGF-β-ERK/MAPK signaling pathway for prophylaxis of endometriosis.

Non-coding RNAs in endometriosis: a narrative review

BACKGROUND

Endometriosis is a benign gynaecological disorder, which affects 10% of reproductive-aged women and is characterized by endometrial cells from the lining of the uterus being found outside the uterine cavity. However, the pathophysiological mechanisms causing the development of this heterogeneous disease remain enigmatic, and a lack of effective biomarkers necessitates surgical intervention for diagnosis. There is international recognition that accurate non-invasive diagnostic tests and more effective therapies are urgently needed. Non-coding RNA (ncRNA) molecules, which are important regulators of cellular function, have been implicated in many chronic conditions. In endometriosis, transcriptome profiling of tissue samples and functional in vivo and in vitro studies demonstrate that ncRNAs are key contributors to the disease process.

OBJECTIVE AND RATIONALE

In this review, we outline the biogenesis of various ncRNAs relevant to endometriosis and then summarize the evidence indicating their roles in regulatory pathways that govern disease establishment and progression.

SEARCH METHODS

Articles from 2000 to 2016 were selected for relevance, validity and quality, from results obtained in PubMed, MEDLINE and Google Scholar using the following search terms: ncRNA and reproduction; ncRNA and endometriosis; miRNA and endometriosis; lncRNA and endometriosis; siRNA and endometriosis; endometriosis; endometrial; cervical; ovary; uterus; reproductive tract. All articles were independently screened for eligibility by the authors.

OUTCOMES

This review integrates extensive information from all relevant published studies focusing on microRNAs, long ncRNAs and short inhibitory RNAs in endometriosis. We outline the biological function and synthesis of microRNAs, long ncRNAs and short inhibitory RNAs and provide detailed findings from human research as well as functional studies carried out both in vitro and in vivo, including animal models. Although variability in findings between individual studies exists, collectively, the extant literature justifies the conclusion that dysregulated ncRNAs are a significant element of the endometriosis condition.

WIDER IMPLICATIONS

There is a compelling case that microRNAs, long non-coding RNAs and short inhibitory RNAs have the potential to influence endometriosis development and persistence through modulating inflammation, proliferation, angiogenesis and tissue remodelling. Rapid advances in ncRNA biomarker discovery and therapeutics relevant to endometriosis are emerging. Unravelling the significance of ncRNAs in endometriosis will pave the way for new diagnostic tests and identify new therapeutic targets and treatment approaches that have the potential to improve clinical options for women with this disabling condition.

New insights on the pathogenesis of endometriosis and novel non-surgical therapies

Endometriosis is a disease of theories, but none has succeeded to explain the whole picture. Most widely available drugs for endometriosis aim to relieve symptoms and improve fertility. Unfortunately, many short and long-term side-effects are associated with the treatments. To overcome this problem, researchers have developed many novel therapeutic agents, including non-invasive technique. We aim to provide new insights on pathogenesis model and novel non-surgical treatments for endometriosis, including drugs already available in the market and also drugs which are still under research. Seven novel treatment modalities are recognized, namely dienogest, aromatase inhibitor (AI), gonadotrophine-releasing hormone (GnRH) antagonist, anti tumor necrosing factor (TNF)-α, selective estrogen receptor modulator (SERM), selective progesterone receptor modulator (SPRM), and high-intensity focused ultrasound (HIFU). Dienogest, AI, and GnRH antagonists are effective novel treatments with good tolerance and safety. SERM and SPRM show inconsistent results, while anti-TNF-α is still in the animal experimental stage. HIFU is a potential futuristic treatment. However, it is still a long way until this technology is truly applicable.

Prevalence and geographical distribution of Papio hamadryas papillomavirus 1 (PhPV1) in Kenyan baboons

Papio hamadryas papillomavirus (PhPV) 1, 2, and 3, are Alphapapillomaviruses that have been detected in Kenyan Olive baboons but the distribution is unknown. Therefore, cervical screening for PhPV1 was performed in baboons from various areas in Kenya using a nested polymerase chain reaction. The prevalence rate was 33%.

Recent advances in the understanding of endometriosis: the role of inflammatory mediators in disease pathogenesis and treatment

In this review, we focus on recent advancements in our understanding of the roles of inflammatory mediators in endometriosis pathophysiology and the potential for improved therapies based upon targeting these pathways. We review the association between endometriosis and inflammation and the initial promise of anti-tumor necrosis factor therapies based upon experimental evidence, and how and why these studies have not translated to the clinic. We then discuss emerging data on the role of inter-relationship among macrophage migration inhibitory factor, prostaglandin E ₂, and estrogen receptor-beta, and the potential utility of targeting these factors in endometriosis treatment. In doing so, we highlight the strengths and discuss the current research on identification of novel, anti-inflammatory-based therapy and the necessity to expand experimental endpoints to include clinically relevant measures when assessing the efficacy of potential new therapies for endometriosis.

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.

Endometriosis research: animal models for the study of a complex disease

Endometriosis is a common gynaecological disease that is characterized and defined as the presence of endometrial tissue outside the uterus, causing painful periods and subfertility in approximately 10% of women. After more than 50 years of research, little is known about the mechanisms underlying the development and establishment of this condition. Animal models allow us to study the temporal sequence of events involved in disease establishment and progression. Also, because this disease occurs spontaneously only in humans and non-human primates and there are practical problems associated with studying the disease, animal models have been developed for the evaluation of endometriosis. This review describes the animal models for endometriosis that have been used to date, highlighting their importance for the investigation of disease mechanisms that would otherwise be more difficult to elucidate, and proposing new alternatives aimed at overcoming some of these limitations.

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).

Nonhuman primate models for translational research in endometriosis

Endometriosis, defined as the ectopic presence of endometrial-like cells, is associated with infertility and pelvic pain in women. Whereas pathogenesis and spontaneous evolution of endometriosis are still poorly understood, recurrences after surgical therapy or after medical treatment are common. Spontaneous endometriosis occurs only in women and in nonhuman primates (NHPs). Inbred rhesus monkeys kept in colonies offer an attractive preclinical model to study the inheritance of spontaneous endometriosis. Baboons with spontaneous or induced endometriosis appear to be the best NHP model to study pathogenesis, pathophysiology, spontaneous evolution and new medical treatment options. In baboons, induction of endometriosis after intrapelvic injection of menstrual endometrium leads to biological changes in peritoneal cavity and in endometrium. This induction process may allows the study of cause-effect relationships which may lead to the discovery of new biomarkers for the development of new non-invasive diagnostic tests and drugs that may prevent or treat endometriosis.

Peritoneal macrophage depletion by liposomal bisphosphonate attenuates endometriosis in the rat model

BACKGROUND

Activation of macrophages is central to the implantation of endometriosis (EM). We examined the hypothesis that macrophage depletion by intraperitoneal (IP) injection of liposomal alendronate (LA) could result in EM attenuation in a rat model, thus supporting the notion of the pivotal role of macrophages in EM pathology.

METHODS

In this study, 90 rats were subjected to an EM model and were divided randomly into seven groups: five groups were treated by 4x once-weekly IP injections of LA (0.02, 0.1, 1, 5 or 10 mg/kg) and the other two groups received saline injections (control) or empty liposomes. Sham-operated rats also received empty liposomes. Depletion of circulating monocytes was determined by flow cytometry analyzes of blood specimens. Four weeks after the initial surgery, the number, size and weight of implants were recorded, adhesions were graded, macrophage infiltration was assessed and the peritoneal fluid was analyzed for monocyte chemotactic protein 1 (MCP-1) and tumor necrosis factor alpha (TNFalpha).

RESULTS

Monocyte depletion following IP LA administration resulted in an inhibitory effect on the initiation and growth of EM implants, as expressed by implantation rate, adhesion scoring, implants' size and weight (>0.1 mg/kg LA, P < 0.05). Reduced numbers of infiltrating macrophages were observed in implants of the 1 mg/kg LA group. Peritoneal fluid MCP-1 levels were negatively correlated with LA dose (P < 0.001), whereas no significant correlation could be found for TNFalpha.

CONCLUSIONS

Macrophage depletion using IP LA has been shown to effectively inhibit the initiation and growth of EM implants, in a rat EM model. The clear dose-response effect may be viewed as a confirmation of the validity of the concept and encourages further study.