Intraperitoneal and subcutaneous treatment of experimental endometriosis with recombinant human interferon-alpha-2b in a murine model

N-Myc and STAT Interactor is an Endometriosis Suppressor

In patients with endometriosis, refluxed endometrial fragments evade host immunosurveillance, developing into endometriotic lesions. However, the mechanisms underlying this evasion have not been fully elucidated. N-Myc and STAT Interactor (NMI) have been identified as key players in host immunosurveillance, including interferon (IFN)-induced cell death signaling pathways. NMI levels are markedly reduced in the stromal cells of human endometriotic lesions due to modulation by the Estrogen Receptor beta/Histone Deacetylase 8 axis. Knocking down NMI in immortalized human endometrial stromal cells (IHESCs) led to elevated RNA levels of genes involved in cell-to-cell adhesion and extracellular matrix signaling following IFNA treatment. Furthermore, NMI knockdown inhibited IFN-regulated canonical signaling pathways, such as apoptosis mediated by Interferon Stimulated Gene Factor 3 and necroptosis upon IFNA treatment. In contrast, NMI knockdown with IFNA treatment activated non-canonical IFN-regulated signaling pathways that promote proliferation, including β-Catenin and AKT signaling. Moreover, NMI knockdown in IHESCs stimulated ectopic lesions' growth in mouse endometriosis models. Therefore, NMI is a novel endometriosis suppressor, enhancing apoptosis and inhibiting proliferation and cell adhesion of endometrial cells upon IFN exposure.

N-Myc and STAT Interactor is an endometriosis suppressor

In patients with endometriosis, refluxed endometrial fragments evade host immunosurveillance, developing into endometriotic lesions. However, the mechanisms underlying this evasion have not been fully elucidated. N-Myc and STAT Interactor (NMI) have been identified as key players in host immunosurveillance, including interferon (IFN)-induced cell death signaling pathways. NMI levels are markedly reduced in the stromal cells of human endometriotic lesions due to modulation by the Estrogen Receptor beta/Histone Deacetylase 8 axis. Knocking down NMI in immortalized human endometrial stromal cells (IHESCs) led to elevated RNA levels of genes involved in cell-to-cell adhesion and extracellular matrix signaling following IFNA treatment. Furthermore, NMI knockdown inhibited IFN-regulated canonical signaling pathways, such as apoptosis mediated by Interferon Stimulated Gene Factor 3, and necroptosis upon IFNA treatment. In contrast, NMI knockdown with IFNA treatment activated non-canonical IFN-regulated signaling pathways that promote proliferation, including β-Catenin and AKT signaling. Moreover, NMI knockdown in IHESCs stimulated ectopic lesions' growth in mouse endometriosis models. Therefore, NMI is a novel endometriosis suppressor, enhancing apoptosis and inhibiting proliferation and cell adhesion of endometrial cells upon IFN exposure.

Immunotherapy: A promising novel endometriosis therapy

Endometriosis is a common disease of the female reproductive system and has malignant features. Although endometriosis by itself is a benign disease, its erosive growth characteristics lead to severe pelvic pain and female infertility. Unfortunately, several aspects of the pathogenesis of endometriosis are still unclear. Furthermore, the clinical therapeutic methods are unsatisfactory. The recurrence rate of endometriosis is high. Accumulating evidence suggests that the onset and development of endometriosis are closely related to the abnormal function of the female autoimmune system, especially the function of some immune cells such as the aggregation of neutrophils, abnormal differentiation of macrophages, decreased cytotoxicity of NK cells, and abnormal function of T- and B-cell lines. Therefore, immunotherapy is probably a novel therapeutic strategy for endometriosis besides surgery and hormone therapy. However, information regarding the clinical application of immunotherapy in the treatment of endometriosis is very limited. This article aimed to review the effects of existing immunomodulators on the development of endometriosis, including immune cell regulators and immune factor regulators. These immunomodulators clinically or experimentally inhibit the pathogenesis and development of endometriosis lesions by acting on the immune cells, immune factors, or immune-related signaling pathways. Thus, immunotherapy is probably a novel and effective clinical treatment choice for endometriosis. Experimental studies of the detailed mechanism of immunotherapy and large-scale clinical studies about the effectiveness and safety of this promising therapeutic method are required in the future.

The latest advances in the pharmacological management of endometriosis

INTRODUCTION

Endometriosis is a benign disease, characterized by a wide range of symptoms and different degrees of severity, which is why therapy should be individually adapted to the patient's needs. Over the years, a lot of research has gone into finding new therapeutic approaches for this enigmatic disease.

AREAS COVERED

This review presents the latest advances in pharmacological management of endometriosis and is solely focused on studies published from 2010 to 2021.

EXPERT OPINION

Clinicians and researchers are constantly searching for new therapeutic strategies for endometriosis patients. As there are well-established treatments, however, any new medication should fulfill at least one of the three criteria: increased efficacy, comparable efficacy but a better safety profile, or treatments that have a lack of accompanying contraceptive effects that are seen in most endometriosis treatments. While some new substances show promising results, further studies are needed to demonstrate the fulfillment of one of the above-mentioned criteria.

Interferon Signaling in the Endometrium and in Endometriosis

Endometriosis is an estrogen-dependent inflammatory disease that develops in reproductive-aged women who experience pelvic pain and infertility. Even though endometriosis is not a new disease, its molecular etiology has not been clearly elucidated. Defects in the immune system might be one of the factors that promote endometriosis progression. For example, elevated levels of proinflammatory cytokines are associated with endometriosis. Interferon is one of the cytokines that is elevated in endometriotic tissues compared with normal endometrium. Therefore, high interferon levels play a crucial role in endometriosis progression. In addition to endometriosis, however, interferon has a critical role in endometrial function, particularly in the initiation and maintenance of pregnancy. Therefore, this review describes the double-edged sword of interferon signaling in normal endometrial function versus endometriosis progression and also discusses interferon targeting as a new nonhormonal therapy for endometriosis. This approach may increase the efficacy of endometriosis treatment and reduce the adverse effects associated with current hormonal therapy for this disease.

Immunoregulation by type I interferons in the peritoneal cavity

The peritoneal cavity, a fluid-containing potential space surrounding the abdominal and pelvic organs, is home to a rich network of immune cells that maintain tissue homeostasis and provide protection against infection. However, under pathological conditions such as peritonitis, endometriosis, and peritoneal carcinomatosis, the peritoneal immune system can become dysregulated, resulting in nonresolving inflammation and disease progression. An enhanced understanding of the factors that regulate peritoneal immune cells under both homeostatic conditions and in disease contexts is therefore required to identify new treatment strategies for these often life-limiting peritoneal pathologies. Type I interferons (T1IFNs) are a family of cytokines with broad immunoregulatory functions, which provide defense against viruses, bacteria, and cancer. There have been numerous reports of immunoregulation by T1IFNs within the peritoneal cavity, which can contribute to both the resolution or propagation of peritoneal disease states, depending on the specifics of the disease setting and local environment. In this review, we provide an overview of the major immune cell populations that reside in the peritoneal cavity (or infiltrate it under inflammatory conditions) and highlight their contribution to the initiation, progression, or resolution of peritoneal diseases. Additionally, we will discuss the role of T1IFNs in the regulation of peritoneal immune cells, and summarize the results of laboratory studies and clinical trials which have investigated T1IFNs in peritonitis/sepsis, endometriosis, and peritoneal carcinomatosis.

Establishment of endometriotic models: the past and future

Endometriosis is a prevalent chronic disease that affects approximately 6% to 10% of reproductive-aged women. Although numerous researchers have endeavored to explore the etiology of endometriosis over a century, its etiology still remains an enigma. The exploration of pathophysiologic mechanism and novel therapy for endometriosis depends on ideal endometriotic models. In the previous decade, various endometriotic models have been established; therefore, we made a conclusion for available information on these models. This review summarized the common experimental models used in endometriotic studies, including their origins, characteristics, applications, and limitations. Endometriotic models played an important role in studying etiologies and novel treatments of endometriosis during the last decades. Among them, animal models and endometriotic cell lines were viewed as most common studying tools to explore the intrinsic entities of endometriosis. In addition, endometrial organoid also emerged and was regarded as an ideal studying tool for endometriosis research. Different research models collectively complement each other to advance the endometriosis research. The successful establishment of endometrial organoids means that organoids are expected to become an ideal model for studying endometriosis in the future.

Inhibition of Histone Methyltransferase EZH2 Suppresses Endometriotic Vesicle Development in a Rat Model of Endometriosis

Endometriosis is a painful gynecological disease with no cure and limited therapeutic options. It has been hypothesized that epigenetic drugs can be used as a nonhormonal treatment for endometriosis. This study was conducted to study the efficacy of an inhibitor of the histone methyltransferase EZH2 using an established rat model of endometriosis. We hypothesized that treatment will block or reduce the number of endometriotic vesicles in this model. We conducted a preclinical drug study in female rats with experimental endometriosis (uterine tissue transplanted next to the intestinal mesentery) or control sham (sutures only). Rats with endometriosis or sham surgery received either treatment with EZH2 inhibitor (5 mg/kg or 10 mg/kg) or vehicle (0.1%, 67% DMSO) every other day during 4 weeks. After treatment completion, the number, area, volume, and weight of vesicles were evaluated. RT [2] Profiler Arrays for neuropathic and inflammation, epithelial to mesenchymal transition, inflammatory response, and autoimmunity pathways were used to examine gene expression changes in the vesicles that developed. Treatment with EZH2 inhibitor (10 mg/kg) suppressed the development of vesicles, by significantly decreasing the total vesicle number, area, volume, and weight. In addition, EZH2 inhibition significantly increased the expression of CACNA1B and FKBP1A genes, involved in pain and proliferation, respectively. EZH2 inhibition suppresses the growth of vesicles without apparent detrimental effects to other organs. Treatment with this epigenetic inhibitor leads to upregulation of a limited number of genes related to endometriosis-relevant pathways. In conclusion, these data support follow-up studies to evaluate its potential as a therapeutic approach for endometriosis.

Effects of human recombinant type I IFNs (IFN-α2b and IFN-β1a) on growth and migration of primary endometrial stromal cells from women with deeply infiltrating endometriosis: A preliminary study

OBJECTIVE(S)

Endometriosis is a major cause of infertility and disability for women, caused by the presence of inflammatory endometrial implants in extrauterine locations. Among the constituents involved in the immune response during the development of endometriosis, several chemokines, including interferons (IFNs) may have a role in the pathogenesis of this disease. The aim of this preliminary study was to investigate the anti-proliferative and anti-migratory activities of type I IFNs (IFN-α2b and IFN-β1a) in primary endometrial stromal cells (ESCs) isolated from women with deeply infiltrating endometriosis (DIE).

STUDY DESIGN

The study subjects included 7 women ranged in the age from 27 to 37 years with diagnosis of DIE (Stage III and IV). Collected primary ESC monolayers, isolated from endometriotic nodules, were incubated with various concentrations (from 1 to 1000 IU/ml) of IFN-α2b or IFN-β1a.

RESULT(S)

IFN-β1a had a significantly higher activity in hampering the proliferation of cells compared to IFN-α2b. This effect could be related to the induction of apoptosis and cell cycle arrest in S phase, observed in ESCs during incubation with IFN-β1a. Moreover, IFN-β1a was more potent than IFN-α2b in inhibiting migration and EGF-induced ERK activity of primary ESCs.

CONCLUSION(S)

The inhibitory in vitro effect on ESC proliferation and migration of IFN-β1a was much more potent than IFN-α2b. These preliminary data offer the rationale for future preclinical and clinical trials using IFN-β1a as a new tool for the therapy and tertiary prevention in patients with DIE.

Stress During Development of Experimental Endometriosis Influences Nerve Growth and Disease Progression

PURPOSE

We have previously shown that stress prior to induction worsens clinical presentation and inflammatory parameters in a rat model of endometriosis. This study was designed to examine whether stress during the development of endometriosis can affect the growth of endometriotic implants through nerve growth and immune alterations.

METHODS

Endometriosis was surgically induced in female Sprague-Dawley rats by suturing uterine horn implants onto the small intestine mesentery. Two weeks later, one group of rats (endo-stress) was subjected to a 10-day swim stress protocol. Controls had no stress (endo-no stress) or sutures only and stress (sham-stress). On day 60, all rats were killed and examined for the presence of endometriotic vesicles. The size of each vesicle was measured. The uterus and colon were removed and assessed for damage, cell infiltration, and expression of nerve growth factor (NGF), its receptors (p75 and Tropomyosin receptor kinase A (Trk-A)/pTrk-A), and calcitonin gene-related peptide, a sensory fiber marker. A differential analysis of peritoneal fluid white blood cell count was performed.

RESULTS

Stress significantly increased endometriotic vesicle size but not colonic damage and increased infiltration of mast cells. Significantly increased expression of NGF and its receptors was found in the uterus of animals with endometriosis receiving stress.

CONCLUSIONS

Stress stimulates the development of ectopic endometrial vesicles in an animal model of endometriosis and increases inflammatory cell recruitment to the peritoneum. In addition, stress promotes nerve fiber growth in the uterus.

Impact of Psychological Stress on Pain Perception in an Animal Model of Endometriosis

PURPOSE

Pain in patients with endometriosis is considered a significant source of stress but does not always correlate with severity of the condition. We have demonstrated that stress can worsen endometriosis in an animal model. Here, we tested the impact of a psychological stress protocol on pain thresholds and pain receptors.

METHODS

Endometriosis was induced in female rats by suturing uterine horn tissue next to the intestinal mesentery. Sham rats had sutures only. Rats were exposed to water avoidance stress for 7 consecutive days or handled for 5 minutes (no stress). Fecal pellets and serum corticosterone (CORT) levels were measured as an index of anxiety. Pain perception was assessed using hot plate and Von Frey tests. Substance P, enkephalin, endomorphin-2, Mu opioid receptor (MOR), and neurokinin-1 receptor expression in the spinal cord were measured by immunohistochemistry.

RESULTS

Fecal pellets and CORT were significantly higher in the endo-stress (ES) group than endo-no stress (ENS; P < .01) and sham-no stress groups (SNS; P < .01). The ES rats had more colonic damage ( P < .001 vs SNS; P < .05 vs ENS), vesicle mast cell infiltration ( P < .01 vs ENS), and more severe vesicles than ENS. The ES developed significant hyperalgesia ( P < .05) but stress reversed the allodynic effect caused by endo ( P < .001). The MOR expression was significantly reduced in ENS versus SNS ( P < .05) and more enkephalin expression was found in endo groups.

CONCLUSION

Animals subjected to stress develop more severe symptoms but interestingly stress seems to have beneficial effects on abdominal allodynia, which could be a consequence of the stress-induced analgesia phenomenon.

Leflunomide—an Immunomodulator—Induces Regression of Endometrial Explants in a Rat Model of Endometriosis

OBJECTIVE

To test if leflunomide, an immunomodulator, could impede the growth of an ectopic uterine tissue.

METHODS

Endometriosis was surgically induced in 26 rats by transplanting an autologous fragment of endometrial tissue onto the inner surface of the abdominal wall. Four weeks later two rats were killed. The volume and weight of the implants were measured. The remaining rats were randomly grouped, and in group 1 no medication was given. To the rats in group 2, 35 mg/kg/d of leflunomide was administered orally. Four weeks later, rats were killed and ectopic uterine tissues were reevaluated morphologically and histologically. A scoring system was used to evaluate preservation of epithelia.

RESULTS

Two rats in the control group died 5 weeks after surgery. There was a significant difference in post-treatment spherical volumes (139.1 +/- 92.8 versus 33.5 +/- 12.5 mm3) and explant weights (156.3 +/- 105.6 versus 38.6 +/- 12.6 mg) between the control and leflunomide-treated groups. The epithelia were found to be preserved significantly better in the control group when compared with the leflunomide-treated group (median 2.5 [interquartile range, 1.25] versus median 1.00 [interquartile range, 1.5]).

CONCLUSION

Leflunomide appeared to cause regression of experimental endometriosis in rats.

Evaluation of peritoneal endometriosis treatment using intralesional acetylsalicylic acid injection in rabbits

PURPOSE

To investigate the efficacy of intralesional 20% aspirin injection for treatment of experimental peritoneal endometriosis.

METHODS

Peritoneal endometriosis was experimentally induced in forty adult nulligravid female rabbits. On day 30 post-endometriosis induction, rabbits were randomly divided to assess early (10 days) and late (20 days) effects of intralesional injection of physiological saline solution (control groups) in comparison to intralesional injection of 20% bicarbonate aspirin solution (experimental groups) as follows: control group 1 (10 days, n=10); control group 2 (20 days, n=10); experimental group 3 (10 days, n=10); experimental group 4 (20 days, n=10). Resected tissues, including endometriosis foci, were qualitatively (general morphology and signs of inflammatory cells infiltrate, necrosis and apoptosis) and quantitatively (remaining endometriosis area) assessed by histopathological analysis.

RESULTS

Extensive necrosis, hemorrhage, apoptosis, and fibrosis were observed in the experimental groups 3 and 4. Groups 1 and 2 presented typical endometrial tissue cysts, respectively. Groups 3 and 4 showed sparse endometrial tissue foci and no endometrial tissue, respectively. Quantitative analysis revealed that aspirin-treated groups 3 and 4 had significantly (p<0.05) smaller remaining endometriosis area, compared to control groups 1 and 2.

CONCLUSION

Intralesional 20% aspirin injection caused total destruction of peritoneal endometriosis foci in rabbits.

Impact of physical activity on pain perception in an animal model of endometriosis

BACKGROUND

Symptoms of endometriosis, such as pain and infertility, are considered significant sources of stress. In many chronic conditions, exercise can act as a stress buffer and influence pain perception. We tested the impact of swimming exercise on pain perception and pain receptors in an animal model of endometriosis.

METHODS

Endometriosis (Endo) was induced in female rats by suturing uterine horn tissue next to the intestinal mesentery. Sham rats received sutures only. Rats were exposed to swimming exercise for 7 consecutive days, while no-exercise rats were left in the home cage. Fecal pellets were counted after swimming as an index of anxiety, and serum corticosterone levels measured. Pain perception was assessed using the hot plate test for hyperalgesia and Von Frey test for allodynia. Mu-opioid receptor (MOR) and neurokinin-1 receptor expression in the spinal cord was measured by immunofluorescence.

RESULTS

Fecal pellet counts were higher in those animals that swam (p<0.05), but no significant difference in corticosterone was found. Although Endo-exercise rats had higher colonic damage (p<0.05) with more cellular infiltration, the lesions were smaller than in Endo-no exercise rats (p<0.05). Exercise did not ameliorate the hyperalgesia, whereas it improved allodynia in both groups. MOR expression was significantly higher in Endo-exercise vs. Endo-no exercise rats (p<0.01), similar to Sham-no exercise levels.

CONCLUSIONS

Our results point toward beneficial effects of swimming exercise during endometriosis progression. Physical interventions might be investigated further for their ability to reduce perceived stress and improve outcomes in endometriosis.

Stress management affects outcomes in the pathophysiology of an endometriosis model

We have previously shown detrimental effects of stress in an animal model of endometriosis. We now investigated whether the ability to control stress can affect disease parameters. Endometriosis was surgically induced in female Sprague-Dawley rats before exposing animals to a controllable (submerged platform) or uncontrollable (no platform) swim stress protocol. Corticosterone levels and fecal pellet numbers were measured as an indicator of stress. Uncontrollable stress increased the number and size of the endometriotic cysts. Rats receiving uncontrollable stress had higher anxiety than those exposed to controllable stress or no stress and higher corticosterone levels. Uncontrollable stressed rats had more colonic damage and uterine cell infiltration compared to no stress, while controllable stress rats showed less of an effect. Uncontrollable stress also increased both colonic and uterine motility. In summary, the level of stress controllability appears to modulate the behavior and pathophysiology of endometriosis and offers evidence for evaluating therapeutic interventions.

Medical treatments for endometriosis-associated pelvic pain

The main sequelae of endometriosis are represented by infertility and chronic pelvic pain. Chronic pelvic pain causes disability and distress with a very high economic impact. In the last decades, an impressive amount of pharmacological agents have been tested for the treatment of endometriosis-associated pelvic pain. However, only a few of these have been introduced into clinical practice. Following the results of the controlled studies available, to date, the first-line treatment for endometriosis associated pain is still represented by oral contraceptives used continuously. Progestins represent an acceptable alternative. In women with rectovaginal lesions or colorectal endometriosis, norethisterone acetate at low dosage should be preferred. GnRH analogues may be used as second-line treatment, but significant side effects should be taken into account. Nonsteroidal anti-inflammatory drugs are widely used, but there is inconclusive evidence for their efficacy in relieving endometriosis-associated pelvic pain. Other agents such as GnRH antagonist, aromatase inhibitors, immunomodulators, selective progesterone receptor modulators, and histone deacetylase inhibitors seem to be very promising, but there is not enough evidence to support their introduction into routine clinical practice. Some other agents, such as peroxisome proliferator activated receptors-γ ligands, antiangiogenic agents, and melatonin have been proven to be efficacious in animal studies, but they have not yet been tested in clinical studies.

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.

Stress exacerbates endometriosis manifestations and inflammatory parameters in an animal model

Women with endometriosis have significant emotional distress; however, the contribution of stress to the pathophysiology of this disease is unclear. We used a rat model of endometriosis to examine the effects of stress on the development of this condition and its influence on inflammatory parameters. Female Sprague-Dawley rats were subjected to swim stress for 10 consecutive days prior to the surgical induction of endometriosis by suturing uterine horn implants next to the intestinal mesentery (endo-stress). Sham-stress animals had sutures only, and an endo-no stress group was not subjected to the stress protocol. At the time of sacrifice on day 60, endometriotic vesicles were measured and colons assessed for macroscopic and microscopic damage. Colonic tissue and peritoneal fluid were collected for inflammatory cell analysis. Endometriosis, regardless of stress, produced a decrease in central corticotropin-releasing factor immunoreactivity, specifically in the CA3 subregion of the hippocampus. Prior exposure to stress increased both the number and severity of vesicles found in animals with endometriosis. Stress also increased colonic inflammation, motility, myeloperoxidase levels, and numbers of mast cells. In summary, prior stress may contribute to the development and severity of endometriosis in this animal model through mechanisms involving cell recruitment (eg, mast cells), release of inflammatory mediators, and deregulation of hypothalamic-pituitary axis responses in the hippocampus.

Treatment of endometriosis with local acetylsalicylic acid injection: experimental study in rabbits

The objective of the present study was to estimate the effects of introduction of acetylsalicylic acid solution into peritoneal implants in autologous endometrium as a method for treating endometriosis. Forty adult female rabbits were subdivided into 4 groups of 10 rabbits each, and endometriosis was induced via autotransplantation of endometrial fragments into the peritoneal cavity. At 30 days after induction of endometriosis, all animals were randomly assigned to 1 of 2 protocols. In protocol 1, animals were evaluated at 24 hours after treatment; group 1 (control) received physiologic solution, and group 2 received acetylsalicylic acid. In protocol 2, animals were evaluated at 10 days after treatment, group 3 (control) and group 4 received acetylsalicylic acid. After measuring the lesion, the endometriotic focus was removed and prepared for mounting on slides for histologic analysis. Imaging software was used for analysis of the total remaining area of endometrial tissue. The affected area in acetylsalicylic acid-treated animals was smaller than that in control animals at 24 hours and 10 days after treatment; a significant difference was found between control and treated groups (p < .001). Statistical analysis comparing protocols 1 and 2 demonstrated no differences between controls groups or acetylsalicylic acid groups (p = .30), and no differences between times (p = .75). Acetylsalicylic acid solution led to less growth (or higher involution) of endometrial implants. Acetylsalicylic acid injected directly into endometriotic foci was effective in their destruction. This presents new perspectives for treatment of endometriosis and for clinical applications based on further clinical studies.

Pentoxifylline for endometriosis

BACKGROUND

Endometriosis is a chronic, recurring condition that occurs during the reproductive years. It is characterized by endometrial tissue developing outside the uterine cavity. This endometrial tissue development is dependent on oestrogen produced primarily by the ovaries and, therefore, traditional management has focused on ovarian suppression. In this review we considered the role of modulation of the immune system as an alternative approach. This is an update of a Cochrane Review previously published in 2009 (Lu 2009).

OBJECTIVES

To assess the effects of pentoxifylline, which has anti-inflammatory effects, in subfertile, premenopausal women for the management of endometriosis.

SEARCH METHODS

For the first publication of this review we searched the following databases (from inception to December 2008) for trials: 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. This search was rerun to 23 November 2011, for this update.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing pentoxifylline with placebo or no treatment, medical treatment, or surgery in subfertile, premenopausal women were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial risk of bias, and extracted data using data extraction forms. We contacted study authors for additional information and data. The domains assessed for risk of bias were sequence generation, allocation concealment, blinding, incomplete outcome data, and selective outcome reporting. Peto odds ratios (OR) 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

Four trials involving 334 participants were included. One RCT [n=34] showed pentoxifylline had no significant effect on reduction in pain (MD -1.60, 95% CI -3.32 to 0.12). There was no evidence of an increase in clinical pregnancy events in the pentoxifylline group compared with placebo (three RCTs [n=67] OR 1.54, 95% CI 0.89 to 266). One RCT studied recurrence of endometriosis [n=88] (OR 0.88,95% CI 0.27 to 2.84). No trials reported the effects of pentoxifylline on the odds of live birth rate per woman, improvement of endometriosis-related symptoms, or adverse events.

AUTHORS' CONCLUSIONS

This review has been updated in 2011. The results of the original review published in 2009 remain unchanged. There is still not enough evidence to support the use of pentoxifylline in the management of premenopausal women with endometriosis in terms of subfertility and relief of pain outcomes.

Transcriptional expression of type-I interferon response genes and stability of housekeeping genes in the human endometrium and endometriosis

Endometriosis is a painful chronic female disease defined by the presence of endometrial tissue implants in ectopic (Ec) locations. The pathogenesis is much debated, and type-I interferons (IFNs) could be involved. The expression of genes of the type-I IFN response were profiled by a specific PCR array of RNA obtained from Ec and eutopic (Eu) endometrium collected from nine endometriosis patients and nine healthy control women. Transcriptional expression levels of selected IFN-regulated and housekeeping genes (HKGs) were investigated by real-time quantitative reverse transcriptase PCR (qRT-PCR). Stably expressed HKGs for valid normalization of transcriptional studies of endometrium and endometriosis have not yet been published. Here, seven HKGs were evaluated for stability using the GeNorm and NormFinder software. A normalization factor based on HMBS, TBP and YWHAZ expression was suitable for normalization of qRT-PCR studies of Eu versus Ec endometrium. In the endometrial cell lines HEC1A, HEC1B, Ishikawa and RL95-2, HMBS and HPRT1 were the most stably expressed. The IFN-specific PCR array indicated significantly different expression of the genes BST2, COL16A1, HOXB2 and ISG20 between the endometrial tissue types. However, by correctly normalized qRT-PCR, levels of BST2, COL16A1 and the highly type-I IFN-stimulated genes ISG12A and 6-16 displayed insignificant variations. Conversely, HOXB2 and ISG20 transcriptions were significantly reduced in endometriosis lesions compared with endometrium from endometriosis patients and healthy controls. In conclusion, appropriate HKGs for normalization of qRT-PCR studies of endometrium and endometriosis have been identified here. Abolished expression of ISG20 and HOX genes could be important in endometriosis.

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.

Endometriosis: current therapies and new pharmacological developments

Endometriosis is a chronic inflammatory condition that is responsive to management with steroids. The establishment of a steady hormonal environment and inhibition of ovulation can temporarily suppress ectopic implants and reduce inflammation as well as associated pain symptoms. In terms of pharmacological management, the currently available agents are not curative, and treatment often needs to be continued for years or until pregnancy is desired. Similar efficacy has been observed from the various therapies that have been investigated for endometriosis. Accordingly, combined oral contraceptives and progestins, based on their favourable safety profile, tolerability and cost, should be considered as first-line options, as an alternative to surgery and for post-operative adjuvant use. In situations where progestins and oral contraceptives prove ineffective, are poorly tolerated or are contraindicated, gonadotrophin-releasing hormone analogues, danazol or gestrinone may be used. Future therapeutic options for managing endometriosis must compare favourably against existing agents before they can be considered for inclusion into current practice. Finally, as reproductive prognosis is not ameliorated by medical treatment, it is not indicated for women seeking conception.

Pentoxifylline versus medical therapies for subfertile women with endometriosis

BACKGROUND

Endometriosis is a chronic, recurring condition that occurs during the reproductive years. It is characterized by endometrial tissue developing outside the uterine cavity. This endometrial tissue development is dependent on estrogen produced primarily by the ovaries and, therefore, traditional management has focused on ovarian suppression. In this review we considered the role of modulation of the immune system as an alternative approach.

OBJECTIVES

To determine the effectiveness and safety of pentoxifylline, which has anti-inflammatory effects, in the management of endometriosis in subfertile, premenopausal women.

SEARCH STRATEGY

We searched the following databases (from inception to December 2008) for trials: 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 pentoxifylline with placebo or no treatment, medical treatment, or surgery in subfertile, premenopausal women were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality, and extracted data using data extraction forms. We contacted study authors for additional information and data. The domains assessed for risk of bias were sequence generation, allocation concealment, blinding, incomplete outcome data, and selective outcome reporting. Odds ratios (OR) 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

Four trials involving 334 participants were included. Results showed pentoxifylline had no significant effect on reduction in pain (one RCT, MD -1.60, 95% CI -3.32 to 0.12). There was no evidence of an increase in clinical pregnancy events in the pentoxifylline group compared with placebo (three RCTs, OR 1.54, 95% CI 0.89 to 266). For recurrence of endometriosis, one RCT reported an OR of 0.88 (95% CI 0.27 to 2.84). No trials reported the effects of pentoxifylline on the odds of live birth rate per woman, improvement of endometriosis-related symptoms, or adverse events.

AUTHORS' CONCLUSIONS

There is not enough evidence to support the use of pentoxifylline in the management of premenopausal women with endometriosis in terms of subfertility and relief of pain outcomes.

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.

Comparison of the effects of cetrorelix, a GnRH antagonist, and leuprolide, a GnRH agonist, on experimental endometriosis

AIM

In the present study, we aimed to compare the effects of cetrorelix and leuprolide on endometriosis.

METHODS

This randomized, placebo-controlled, single-blind, experimental study was performed on 45 Wistar adult female rats in the Experimental Surgery Laboratory at Ondokuz Mayis University. After the peritoneal implantation of endometrial tissue, rats were randomized to three equal intervention groups: (i) control group, (ii) leuprolide group, and (iii) cetrorelix group. Six weeks later, following implant volume measurements (volume-1) by performing a second laparotomy, saline (0.1 cc/rat) was administered subcutaneously to the control group once a week, leuprolide (0.075 mg/kg) subcutaneously to the leuprolide group twice at 4-week intervals and cetrorelix (0.001 mg/rat/day) subcutaneously to the cetrorelix group for 8 weeks. At the end of the treatment, by performing a third laparotomy, implant volumes were remeasured (volume-2) and implants were totally excised for histopathological examination. The volume-1 and volume-2 values within the groups, and stromal and glandular tissue scores between the groups were compared.

RESULTS

In both the leuprolide group and the cetrorelix group, volume-2 as compared to volume-1 had significantly reduced (P < 0.01, P < 0.01 respectively), while there was no significant volume change in the control group (P > 0.05). In this group, when compared with the control group, glandular and stromal tissues had significantly lessened (P < 0.01, P < 0.01 respectively).

CONCLUSION

Leuprolide and cetrorelix were found to have similar efficacy in the regression of both the size and the histological structure of experimental endometriotic implants.

New drugs in development for the treatment of endometriosis

Endometriosis is a common and enigmatic disease causing pelvic pain and infertility. Current treatment is mainly based on the use of surgery and ovarian suppressive agents. There is in particular the need for new therapeutic options able to allow a normal menstrual cycle to occur and also consent pregnancy. In the present review, we aimed to give a concise and practical overview in order to allow the clinician to clearly understand the level of development of these drugs. We have presented only treatments supported by in vivo researches with a special attention to studies in humans. Results show appealing new possibilities are emerging from agents counteracting the endometriosis-associated inflammation. Recent data also suggests that there is still the opportunity to refine the use of already available agents.

Novel noninvasive detection method for endometriosis: research and development of scintigraphic survey on endometrial implants in rats

In this experimental study on endometriosis, the majority of the implants were successfully detected with technetium-(99mTc) labeled red blood cell scintigraphy.

Treatment strategies for endometriosis

BACKGROUND

Endometriosis is a common chronic disease that causes symptoms of pain and infertility. The pain syndrome can be quite incapacitating. The pain symptoms usually originate in the reproductive organs but can also involve the urinary or intestinal tracts if endometriosis implantation has occurred there. The presentation and physical appearance of endometriosis is extremely variable and can be characterized by a chronic intraperitoneal inflammatory process and adhesions. The only definitive diagnostic technique is laparoscopy.

OBJECTIVE

To review current literature on the treatment strategies for endometriosis.

METHODS

Review of Pubmed, Cochrane database and Medline for current review articles and studies regarding the current treatment strategies for endometriosis.

RESULTS

Initial treatment is surgical or medical. Medical therapy is often used as a first-line therapy and can also be used in conjunction with those patients who undergo surgical therapy for pain. No medical therapy has proven effective for infertility. Medical therapy consists mostly of hormonal suppressive therapy in which the medication causes a downregulation of the hypothalamus-pituitary-ovarian pathway. Non-steroidal anti-inflammatory drugs and oral contraceptives are often used as an initial approach even without a definitive diagnosis. Progestins, such as oral norethindrone and depot medroxyprogesterone, are effective while using them but have a high recurrence rate. The norgestrol intrauterine device is also quite effective at relieving pain associated with endometriosis, especially pain arising during menses as well as from lesions in the rectovaginal tissue. Gonadotropin-releasing hormone agonists induce a pseudomenopausal state and have significant side effects, such as hot flashes and genital atrophy. 'Add-back' therapy with a progestin has been shown to relieve most of these drug related symptoms. Gonadotropin-releasing hormone agonists are also very effective at relieving symptoms of pain during treatment but are also associated with a high recurrence rate. New drug therapies that are under investigation are aromatase inhibitors and immunomodulators. Furthermore, new delivery systems are being investigated that may also improve the patient response.

Experimental endometriosis in the rat is correlated with colonic motor function alterations but not with bacterial load

Endometriosis commonly presents with symptoms that mimic chronic gastrointestinal disorders. The authors used the autotransplantion model of endometriosis in rats to investigate the possible underlying mechanisms. After the rats were killed, the presence of endometriotic vesicles, colonic inflammation, and white blood cell (WBC) numbers in the peritoneal fluid was determined. Sections of colon and of jejunum were collected for measurement of myeloperoxidase (MPO) activity and bacterial counts, and isometric recording in response to acetylcholine was measured in segments of longitudinal and circular smooth muscle. Experimental animals had significantly more colonic damage, MPO activity, and WBC numbers than controls did. There was no significant difference in the total bacterial load; however, experimental animals demonstrated an increased tension in the longitudinal muscle, which correlated with WBC numbers and colonic damage. In summary, this study presents evidence for a significant effect of peritoneal endometriosis on colonic function and integrity, which may help explain the gastrointestinal symptoms associated with this disease.

The effect of intraperitoneal interleukin-2 on surgically induced endometriosis in rats

OBJECTIVE

To evaluate the effect of interleukin-2 (IL-2) on an experimental model of endometriosis.

STUDY DESIGN

Double blind and randomized experimental prospective placebo-controlled study. Experimental endometriosis was induced in 66 three-month-old female Wistar rats, by auto-transplanting fragments of endometrium to the peritoneum. After four weeks, the size of each implant was measured in millimeters by laparotomy (L2), and animals were randomly distributed for intraperitoneal administration of human-IL-2, rat-IL-2 or placebo. Four weeks later, the implants were measured (L3) and a second dose was given. After four weeks, endometriosis size was evaluated again (L4).

RESULTS

We found a reduction of experimental endometriosis at L3 that was only significant in IL-2 treated groups: 20.1% and 30.3% with human-IL-2 and rat-IL-2, respectively (p<0.001 with respect to L2 size), versus a non-significant reduction of 9.0% found in placebo group, but the differences were not statistically significant between groups. The decrease after a second dose (L4) was: 49.8%, 41.8% and 11.4% with human-IL-2, rat-IL-2 and placebo, respectively (p<0.001 in IL-2 groups versus L2 and L3, and p<0.05 in both groups versus placebo at L4).

CONCLUSION

Intraperitoneal administration of IL-2 reduces experimental endometriosis, and this effect is similar using rat-IL-2 or human IL-2 (non specie-specific effect).

Efficacy of levamisole on experimental endometriosis

OBJECTIVE

To investigate the efficacy of levamisole on experimental endometriosis.

METHODS

After the implantation of endometrial tissue on abdominal peritoneum, 40 rats were randomized to 1 of 4 equal intervention groups. Levamisole (2 mg/rat) was applied subcutaneously to group "L" once a week. Depot medroxyprogesterone acetate (3 mg/kg) was applied intramuscularly to group "M" twice at 4-week intervals. Leuprolide (0.075 mg/kg) was applied subcutaneously to group "G" twice at 4-week intervals. Saline (0.1 cm(3)/rat) was applied subcutaneously to group "C" once a week for 8 weeks. The efficacy of levamisole was determined by volume measurement and characterizing the histological structure of the implants.

RESULT

Volume increase of the implants in group C (P<0.05), and volume decrease in groups M, G, and L was found (P<0.05, P<0.01, and P<0.01, respectively.) Stromal tissue and glandular activity were not different between groups L and G.

CONCLUSION

Levamisole was found to be as effective as leuprolide in regression of the volume of endometriotic implants.

Intraperitoneal recombinant interleukin-2 activates leukocytes in rat endometriosis

The aim of this double-blinded study was to determine changes in leukocyte populations in blood, peritoneal lavage fluid, eutopic and ectopic endometrium after treatment with recombinant rat interleukin-2 (IL-2) using an in vivo experimental model of rat endometriosis. The in vivo model involved transplanting four square fragments of autologous endometrium onto the inner surface of the abdominal wall in 20 Wistar rats. The control group was constituted by 20 sham-operated rats. Both groups were randomly treated (1-month interval treatment) with 2 intraperitoneal doses of glucose solution (5%) that did or did not contain recombinant IL-2, and animals were sacrificed 4 weeks after the last dose of treatment. Blood and peritoneal lavage were obtained during the initial and final laparotomy, whereas eutopic and ectopic endometrium were collected at the end of the experiment. Endometriotic implants were measured in each laparotomy to determine any change in size. Leukocyte populations were analyzed by flow cytometry and immunofluorescence microscopy. Cytometric results were similar in blood and peritoneal lavage. CD25+ and natural killer (NK) cell levels in peripheral blood were lower in rats with endometriosis treated with IL-2, whereas NK cells increased in lavage compared to placebo group. The percentage of macrophages and dendritic cells in blood were higher in all rats treated with IL-2, as well as peritoneal dendritic cells. Implant size of these rats decreased significantly, showing a greater number of activated lymphocytes, macrophages, NK and dendritic cells inside them. In conclusion, recombinant IL-2 induced recruitment of activated leukocytes into endometriotic-like foci, and this was related to a reduction of the implant size, suggesting potential effectiveness of IL-2 as an immunomodulatory agent in this pathology.

Molecular profiling of experimental endometriosis identified gene expression patterns in common with human disease

OBJECTIVE

To validate a rat model of endometriosis using complimentary DNA (cDNA) microarrays by identifying common gene expression patterns between experimental and natural disease.

DESIGN

Autotransplantation rat model.

SETTING

Medical school department.

ANIMALS

Female Sprague-Dawley rats.

INTERVENTION(S)

Endometriosis was surgically induced by suturing uterine horn implants next to the small intestine's mesentery. Control rats received sutures with no implants. After 60 days, endometriotic implants and uterine horn were obtained.

MAIN OUTCOME MEASURE(S)

Gene expression levels determined by cDNA microarrays and real-time quantitative polymerase chain reaction (qPCR). The Cy5-labeled cDNA was synthesized from total RNA obtained from endometriotic implants. The Cy3-labeled cDNA was synthesized using uterine RNA from a control rat. Gene expression levels were analyzed after hybridizing experimental and control labeled cDNA to PIQOR (Parallel Identification and Quantification of RNAs) Toxicology Rat Microarrays (Miltenyi Biotec, Cologne, Germany) containing 1,252 known genes. The Cy5/Cy3 ratios were determined, and genes with >2-fold higher or <0.5-fold lower expression levels were selected. Microarray results were validated by QRT-PCR.

RESULT(S)

We observed differential expression of genes previously shown to be up-regulated in patients, including growth factors, inflammatory cytokines/receptors, tumor invasion/metastasis factors, adhesion molecules, and antiapoptotic factors.

CONCLUSION(S)

This study presents evidence in support of using this rat model to study the natural history of endometriosis and to test novel therapeutics for this incurable disease.

PPAR-gamma receptor ligand induces regression of endometrial explants in baboons: a prospective, randomized, placebo- and drug-controlled study

OBJECTIVE

To determine the effects of a thiazolidinedione (TZD) agonist of peroxisome proliferator-activated receptor (PPAR)-gamma, rosiglitazone, in a baboon model of established endometriosis.

DESIGN

Prospective, randomized, placebo-controlled study.

SETTING

Experimental surgery laboratory at the Institute of Primate Research in Nairobi, Kenya.

ANIMAL(S)

Endometriosis was induced using intrapelvic injection of eutopic menstrual endometrium in 12 female baboons with a normal pelvis that had undergone at least one menstrual cycle since the time of captivity.

INTERVENTION(S)

Induction of endometriosis by laparoscopy was performed in 12 baboons with a normal pelvis. Endometrial tissue was extracted from each baboon by curettage, and a standard amount of endometrium was then seeded onto several peritoneal sites. About 34-68 days after the induction of laparoscopy, a pretreatment laparoscopy (baseline disease assessment) was performed in the baboons to record the extent of endometriotic lesions. The 12 baboons were randomized into three groups and treated from the day after the staging laparoscopy for a total duration of 30 days. They received phosphate-buffered saline tablets (n = 4, placebo control; placebo tablets once a day by mouth for 30 days), GnRH-antagonists (n = 4, active control; ganirelix acetate 125 microg/day for 30 days), or rosiglitazone (n = 4, test drug, 2 mg by mouth each day for 30 days). A third and final laparoscopy on day 30 after the start of treatment was performed to record the extent of endometriosis. The type of lesion (typical, red, white, or suspicious) was recorded. Biopsies were obtained to confirm the histological presence of endometriosis.

MAIN OUTCOME MEASURE(S)

A videolaparoscopy was performed 30 days after treatment to document the number and surface area of endometriotic lesions as well as to calculate the revised American Society for Reproductive Medicine score and stage.

RESULT(S)

The surface area of endometriotic lesions was statistically significantly lower in rosiglitazone-treated baboons when compared with the placebo group. Baboons treated with rosiglitazone or ganirelix had a greater negative relative change in surface area of peritoneal endometriotic lesions than controls. The overall weighted appearance of the lesion types suggests that rosiglitazone may deter the development of newer endometriotic lesions.

CONCLUSION(S)

A PPAR-gamma ligand, rosiglitazone, effectively diminishes the burden of endometriosis disease in a baboon endometriosis model. This animal model holds promise that a TZD drug may be helpful in women with endometriosis.

Pentoxifylline therapy after laparoscopic surgery for different stages of endometriosis: a prospective, double-blind, randomized, placebo-controlled study

STUDY OBJECTIVE

To evaluate the effects of pentoxifylline administration on patients with different stages of endometriosis on whom laparoscopy was performed.

DESIGN

Prospective, double-blind, randomized, placebo-controlled clinical (Canadian Task Force classification I).

SETTING

University and private hospitals.

PATIENTS

Eighty-eight women, all with infertility, some with dysmenorrhea, dyspareunia, or pelvic pain, on whom a laparoscopic diagnosis of endometriosis was made.

INTERVENTIONS

The treatment group received 800 mg pentoxifylline daily for 6 months immediately after surgery. The control group received placebo capsules. All patients were followed-up for 1 year thereafter.

MEASUREMENTS AND MAIN RESULTS

A comparison of pregnancy rate and recurrence of signs and symptoms in the 2 groups was performed. Forty-three patients were studied in the pentoxifylline group and 45 in the placebo group. The cumulative pregnancy rate was 39.5% and 35.6% in the treatment and control groups, respectively. The overall recurrence of signs and symptoms was 14% in the former group and 15.6% in the latter. There were no statistically significant differences between the 2 groups in rates of pregnancy and recurrence (p = .700 and .832, respectively). Nor was there any significant statistical difference between the same stages in the 2 groups regarding immunomodulation.

CONCLUSIONS

According to the results of this study, and while keeping in mind that appropriate surgery is the main aspect of endometriosis treatment, there is no evidence that immunomodulation with pentoxifylline aids fertility or lessens recurrence of signs and symptoms in women with different stages of endometriosis (i.e., minimal, mild, moderate, or severe).

Emerging drugs in endometriosis

Endometriosis is a common, estrogen-dependent, gynaecological disease, defined as the presence of endometrial-like tissue outside the uterus. Although several medications are used for treatment of the disease, they are associated with high recurrence rates, considerable side effects and limited duration of application. Due to these limitations and to the impact of endometriosis on the quality of life of affected women, their environment and the society, there is a great need for new drugs able to abolish endometriosis and its symptoms. Studies in recent years investigating the (patho)physiological mechanisms involved in disease aetiology have fostered the development of novel therapeutic concepts for endometriosis, by targeting the hypothalamic-pituitary-gonadal axis, by selective modulation of estrogenic and progestogenic pathways, by inhibiting angiogenesis or by interfering with inflammatory and immunological factors. This article presents a brief summary of the currently available medications and an overview regarding the development of some of the most interesting and/or most promising novel drug candidates for endometriosis.

Animal models in endometriosis research

Endometriosis is a common gynaecological disease, defined as the presence of endometrial tissue outside the uterus, causing pelvic pain and subfertility in approximately 10% of women of reproductive age. Current therapies lead to pain relief, however, do not address the causes and entail severe side effects. Still little is known about the pathogenic processes leading to the development and maintenance of endometriosis. Because endometriosis occurs spontaneously only in humans and some non-human primates, animal models of induced endometriosis have been developed and are of high value for the evaluation of pathophysiological mechanisms underlying the development of this disease. These experimental models include the autotransplantation of uterine fragments into the peritoneal cavity of rodents and non-human primates or the heterotransplantation of human endometrial or endometriotic tissue to immunodeficient mice or onto the chicken chorioallantoic membrane (CAM). This review describes the animal models for endometriosis and assesses their different potentials and limitations in regard to endometriosis research, with the aim of developing novel non-invasive diagnostic tools and improved strategies for the treatment of endometriosis in women.

Investigational drugs for endometriosis

Endometriosis is an enigmatic disease found in as many as 30% of reproductive age women. The symptoms for women who suffer from this malady vary but may include subfertility or chronic pelvic pain. Because endometriosis lesions rely on estradiol for growth, most of the existing drug regimens work by creating hypoestrogenism. Unfortunately, this leads to untoward side effects and alterations in ovulation and, subsequently, fertility potential. Newer drugs are currently under investigation that either create hypoestrogenemia more efficaciously or do not alter ovulation but still affect the growth of endometriosis. They target some of the pathophysiological pathways that are only now being elucidated, and include gonadotropin-releasing hormone antagonists, aromatase inhibitors, selective progesterone receptor modulators, angiogenesis inhibitors, matrix metalloprotease inhibitors, estrogen receptor beta-agonists and immune modulators.

Medical management of endometriosis

Current approved medical therapies for endometriosis rely on drugs that suppress ovarian steroids and induce a hypoestrogenic state, which determines the atrophy of the ectopic endometrium. Gonadotropin-releasing hormone analogs such as danazol, progestogens and estrogen-progestin combinations have all proven effective in relieving pain and reducing the extent of endometriotic implants. However, symptoms often recur after discontinuation of therapy and hypoestrogenism-related side effects limit the long-term use of most medications. Recently, knowledge of the pathogenesis of endometriosis, particularly at the molecular level, has grown substantially, providing a rational basis for the development of new drugs with precise targets that may be safely administered over the long term.

Effect of BCG vaccine on peritoneal endometriotic implants in a rat model of endometriosis

OBJECTIVE

To investigate the effect of Bacillus Calmette-Guerin (BCG) vaccine on peritoneal implantation of endometrial tissue in rats.

METHODS

Forty sexually mature virgin Wistar albino rats weighing 190-200 g were randomly assigned (double blind) to two groups. The rats in the first group were vaccinated with 0.1 mL BCG and those in the second group were injected with 0.1 mL saline into the tail, intracutaneously. All the rats underwent median laparotomy after 4 weeks of vaccination or injection. The right uterine horn was excised, and the two samples of endometrial tissue dissected from myometrium were implanted on each side of peritoneum at the 2 cm lateral line of the median laparotomy incision. The implanted peritoneal segments were excised after 8 weeks of laparotomy. The tissue samples were accepted, histologically, as endometriosis when both glands and stroma of endometrial tissue were seen in sections.

RESULTS

Thirty-six implants from the study group and 34 implants from the control group were obtained. Ten and 23 implants were accepted as endometriosis in the study and control group, respectively. The number of endometriotic foci were significantly lower in the study group than in the control group (P = 0.01).

CONCLUSIONS

Stimulation of the cellular immune response with BCG vaccine could exert an inhibitory effect on ectopic endometriotic implants.