Therapeutic effect of angiostatin gene transfer in a murine model of endometriosis

Treatment of endometriosis with a VEGF-targeted conditionally replicative adenovirus

OBJECTIVE

To evaluate a vascular endothelial growth factor (VEGF)-targeted gene therapy for the treatment of endometriosis.

DESIGN

Analysis of the VEGF gene expression and promoter activity in ectopic and eutopic endometrium. Evaluation of the specific replication and cell-killing effect of a VEGF-targeted adenovirus (Ad5VEGFE1) in endometriotic cells.

PATIENT(S)

Four patients who underwent hysterectomy for benign disease, 30 women with moderate superficial, and 30 women with deep infiltrating endometriosis.

INTERVENTION(S)

Immunostaining and gene expression of VEGF was examined in eutopic endometrium, endometriotic lesions, and normal peritoneum. The VEGF promoter activity was evaluated in eutopic endometrium and endometriotic lesions. A VEGF-targeted conditionally replicative adenovirus (Ad5VEGFE1) was evaluated regarding specific viral replication in endometriosis cells and induction of apoptosis. The biodistribution of the VEGF-targeted conditionally replicative adenovirus was examined in a mouse model.

RESULT(S)

The VEGF gene was highly expressed in ectopic endometrium compared with eutopic endometrium and normal peritoneum. The VEGF promoter was active in endometriotic cells. Ad5VEGFE1 showed efficient viral replication and induction of apoptosis in purified primary endometriotic cells and demonstrated a similar lower targeting to the liver and the uterus in a mouse model.

CONCLUSION(S)

Ad5VEGFE1 is a promising candidate for treating endometriosis and holds potential for clinical testing.

The inhibitory effect of 15-R-LXA4 on experimental endometriosis

OBJECTIVE

To determine the pro-resolution actions of 15-R-LXA(4) (LXA(4)) on endometriotic lesions and on the expression of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in the murine endometriosis model.

STUDY DESIGN

In a prospective, placebo-controlled experimental study, endometriosis was induced in thirty BALB/c mice, and fifteen sham-operated mice served as negative controls. Among the thirty mice with induced endometriosis, fifteen were administered 15-R-LXA(4) and acted as study group (LXA(4) group) and the other fifteen were used as positive controls (EM group). Then all the mice were sacrificed and the endometriotic lesions were weighed. The mRNA and protein levels of IL-1beta and TNF-alpha in the peritoneal fluid were quantified by using real-time polymerase chain reaction (PCR) and enzyme-linked immunoabsorbent assay (ELISA).

RESULT(S)

Compared with the positive controls, 15-R-LXA(4) reduced the weight of the endometriotic lesions, decreased the concentrations of IL-1beta and TNF-alpha, and lowered the mRNA levels of IL-1beta and TNF-alpha in peritoneal fluid cells.

CONCLUSION(S)

These findings suggest that 15-R-LXA(4) inhibits the progression of endometriosis possibly by suppressing the gene and protein expression of IL-1beta and TNF-alpha.

Change of proinflammatory cytokines follows certain patterns after induction of endometriosis in a mouse model

OBJECTIVE

To examine the change in proinflammatory cytokines in the pathologic processes of endometriosis in mice.

DESIGN

A dynamic study on a murine model of endometriosis.

SETTING

Medical school.

ANIMAL(S)

Female BALB/c mice.

INTERVENTION(S)

Endometriosis was induced by injecting endometrial fragments of syngenic mice into the peritoneal cavity of model mice; in control group, phosphate-buffered saline instead of fragments was injected. The peritoneal fluid and the endometriotic lesions were harvested 1 to 21 days after the induction.

MAIN OUTCOME MEASURE(S)

The endometriotic lesions were weighed, the gene and protein levels of some proinflammatory cytokines, including interleukin 1beta, tumor necrosis factor alpha, vascular endothelial growth factor, and monocyte chemoattractant protein 1, were determined by real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively.

RESULT(S)

The levels of these cytokines reached the first peak on the first day and no endometriotic lesions were found. The lesions began to appear on the second day, presenting red color during the initial 6 days, and then they turned dark-red, brown, or bluish. The adhesion took place on the 9th day, and all the lesions evolved into white or transparent cysts on the 15th day. Corresponding to these changes, the second and the third peaks were identified during the 3rd-6th day and the 12th-15th day, respectively.

CONCLUSION(S)

The change pattern of cytokines over time might bear some relationship with the development and progression of the endometriosis.

15-Epi-lipoxin A(4) inhibits the progression of endometriosis in a murine model

OBJECTIVE

To examine the pro-resolution actions of 15-epi-lipoxin A(4) (LXA(4)) on endometriotic lesions, on the concentrations and activities of matrix metalloproteinases (MMP-2 and MMP-9) in murine endometriosis.

DESIGN

Prospective, vehicle-controlled experimental study.

SETTING

Animal research facility.

ANIMAL(S)

BALB/c mice.

INTERVENTION(S)

Endometriosis (EM) was induced in 30 mice. Fifteen of them were administered LXA(4) for 24 days (LXA(4) group), whereas the other 15 served as a control group (EM group). Another 15 sham-operated mice (sham-operated group) were treated with vehicles.

MAIN OUTCOME MEASURE(S)

The weight of the endometriotic lesions was measured. The concentrations, mRNA, and activities of MMP-2 and MMP-9 were determined by enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, and gelatin zymography, respectively.

RESULT(S)

Compared with EM group, the weight of the endometriotic lesions was decreased, the concentrations of MMP-2 and MMP-9 dropped, the mRNA levels of MMP-2 and MMP-9 in the peritoneal fluid cells and the endometriotic lesions were reduced, and the activities of MMP-2 and MMP-9 were inhibited in the LXA(4) group.

CONCLUSION(S)

LXA(4) may inhibit the progression of endometriosis possibly by lowering the concentrations and the activities of MMP-2 and MMP-9.

Effect of pentoxifylline on vascular endothelial growth factor C and flk-1 expression on endometrial implants in the rat endometriosis model

OBJECTIVE

To investigate the effects of pentoxifylline, on vascular endothelial growth factor (VEGF)-C and flk-1 expression in the rat endometriosis model.

DESIGN

Prospective, randomized, placebo-controlled study.

SETTING

Academic institution.

ANIMAL(S)

Twenty Wistar rats with surgically induced endometriosis.

INTERVENTION(S)

Animals were evaluated after surgical induction of endometriosis and random allocation to a group that received pentoxifylline and a control group that received NaCl 0.9%, for 3 weeks. At the end of the treatment period the animals were killed and the implants evaluated macroscopically as well as by immunohistochemistry.

MAIN OUTCOME MEASURE(S)

Morphologic changes of the endometriotic implants; and evaluation of VEGF-C and flk-1 expression by a semiquantitative analysis (HSCORE) for the intensity of immunohistochemical reactivity.

RESULT(S)

A significant reduction was observed in the mean volume of the endometriotic implants per animal in the treatment group as compared with the control group. There was a significant reduction not only in the mean volume of implants per animal but also in the mean number of implants per animal after treatment. By immunohistochemical evaluation (HSCORE), there was a significant reduction in VEGF-C expression after treatment in all areas examined. A significant reduction of flk-1 expression was also noted in the glandular compartment after treatment but not in the epithelial surface or stroma.

CONCLUSION(S)

Pentoxifylline may cause suppression of endometriotic lesions by suppressing angiogenesis through VEGF-C and flk-1 expression.

Anti-angiogenic effects of green tea catechin on an experimental endometriosis mouse model

BACKGROUND

The development of new blood vessels plays an essential role in growth and survival of endometriosis. Epigallocatechin gallate (EGCG) from green tea has powerful anti-angiogenic properties and our aim was to evaluate these properties in experimental endometriosis.

METHODS AND RESULTS

Eutopic endometrium from endometriosis patients was transplanted s.c. to severely compromised immunodeficient mice, randomly treated i.p. with EGCG (anti-angiogenic and -oxidant), Vitamin E (a non-angiogenic antioxidant) or saline for 2 weeks. The endometrial implant, including adjacent host outer skin and subcutaneous layers plus inner abdominal muscle and peritoneum, was collected. New microvessels were determined by species-specific immunohistochemistry. Angiogenic factors in lesions and abdominal muscle were detected by quantitative real-time PCR. Apoptosis was studied by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling and quantitative real-time PCR. In saline control, endometrial implants developed new blood vessels with proliferating glandular epithelium and were tightly adhered to host subcutaneous and abdominal muscle layers. After EGCG, endometriotic lesions were smaller than control (P < 0.05), and glandular epithelium was smaller and eccentrically distributed. Angiogenesis in lesions from the implant and adjacent tissues was under-developed, and microvessel size and density were lower (both P < 0.01) than control. mRNA for angiogenic vascular endothelial growth factor A, but not hypoxia inducible factor 1, alpha subunit, was significantly down-regulated in lesions after EGCG (P < 0.05). In addition, apoptosis in the lesions was more obvious, and nuclear factor kappa B and mitogen activated protein kinase 1 mRNA levels were up-regulated (P < 0.05) after EGCG treatment. No differences were observed with Vitamin E treatment.

CONCLUSIONS

EGCG significantly inhibits the development of experimental endometriosis through anti-angiogenic effects.

Toward gene therapy of endometriosis: transductional and transcriptional targeting of adenoviral vectors to endometriosis cells

OBJECTIVE

The purpose of this study was to screen a panel of targeted adenoviruses as vectors for endometriosis gene therapy.

STUDY DESIGN

Endometriotic cells were obtained from subjects with ovarian endometriomas. Liver tissues were taken from donors during hepatic transplantation surgery. Human endometriotic cells and liver tissues were transfected by targeted adenoviruses expressing luciferase reporter gene. Luciferase activity that was mediated by each virus was expressed as a percentage of adenovirus serotype 5 (Ad5-CMV-luc) activity. The 2-tailed Studentt test was used to compare the adenovirus data.

RESULTS

In endometriotic cells, the adenovirus-RGD (Ad-RGD-luc), adenovirus under secretory leukocyte protease inhibitor promoter (Ad-SLPI-luc), and adenovirus under heparanase promoter (Ad-heparanase-luc) showed significantly higher activity, compared with the adenovirus serotype 5. In liver tissues, adenovirus-survivin (Ad-survivin-luc) and Ad-heparanase-luc had significantly lower activity, compared with adenovirus serotype 5.

CONCLUSION

Ad-heparanase-luc showed "endometriosis on, liver off" phenotype and is a promising vector for endometriosis gene therapy.

Estrogens and progesterone as neuroprotectants: what animal models teach us

Estradiol and progesterone are two steroid hormones that target a variety of organ systems, including the heart, the bone and the brain. With respect to the latter, a large volume of basic science studies support the neuroprotective role of estradiol and/or progesterone. In fact, the results of such studies prompted the assessment of these hormones as protective agents against such disorders as Alzheimer's disease, stroke and traumatic brain injury. Interestingly, results from the Women's Health Initiative (WHI) yielded results that appeared to be inconsistent with the data derived from in vitro and in vivo models. However, we argue that the results from the basic science studies were not inconsistent with the clinical trials, but rather, are consistent with, and may even have predicted, the results from the WHI. To illustrate this point, we review here certain in vivo paradigms that have been used to assess the protective effects of estrogens and progesterone, and describe how the results from these animal models point to the importance of the type of hormone, the age of the subjects and the method of hormone administration, in determining whether or not hormones are neuroprotective.

Gene therapy of gynaecological diseases

Gene therapy represents a potentially useful approach for the treatment of diseases refractory to conventional therapies. Various preclinical and clinical strategies have been explored for treatment of gynaecological diseases. Given the most severe unmet clinical need, much of the work has been performed with gynaecological cancers and ovarian cancer in particular. Although the safety of many treatment strategies has been demonstrated in early phase clinical trials, efficacy has been mostly limited heretofore. Major challenges include improving the vectors used with the aim of more effective and selective delivery. In addition, effective penetration into and spreading within advanced and complex tumour masses and metastases remains challenging. This review focuses on existing and developmental gene transfer applications for gynaecological diseases.

Dendritic cells support angiogenesis and promote lesion growth in a murine model of endometriosis

Endometriosis affects 10-15% of women and is associated with pelvic pain and infertility. Angiogenesis plays an essential role in its pathogenesis. Dendritic cells (DCs) were recently implicated in supporting tumor angiogenesis. As both tumors and endometriosis lesions depend on angiogenesis, we investigated the possibility that DCs may also play a role in endometriosis. We induced endometriosis in 8-wk-old female C57BL/6 mice by implantation of autologous endometrium into the peritoneal cavity. We observed an abundance of CD11c(+) DCs infiltrating sites of angiogenesis in endometriosis lesions. We noticed a similar pattern of infiltrating DCs at sites of angiogenesis in the peritoneal Lewis lung carcinoma tumor model. These DCs were immature (major histocompatability complex class II(low)) and expressed vascular endothelial growth factor receptor 2. Peritoneal implanted bone marrow-derived DCs (BMDCs) incorporated into both endometriosis lesions and into B16 melanoma tumors and enhanced their growth at 8 days compared with controls (5.1+/-2.5 vs. 1.5+/-0.5 mm(2), n=4 and 4, P<0.0001 for endometriosis; 67.6+/-15.1 vs. 22.7+/-14.6 mm(2), n=5 and 7, P=0.0004 for mouse melanoma). Finally, immature BMDCs but not mature BMDCs enhanced microvascular endothelial cell migration in vitro (219+/-51 vs. 93+/-32 cells, P=0.02). Based on these findings, we suggest a novel role for DCs in supporting angiogenesis and promoting lesion growth both in endometriosis and in tumors.

Angiogenesis and antiangiogenic therapy in endometriosis

Endometriosis, the presence of endometrium-like tissue outside of the uterine cavity, is a common disease among women of reproductive age. Typical symptoms include abdominal pain and painful menstruation. In addition, endometriosis is associated with reduced fertility. Current treatment modalities, the surgical removal of endometriotic lesions and the hormonal suppression of estrogen are associated with significant morbidity, side-effects and recurrence rates. Despite uncertainties about the pathophysiology of the disease it has recently become apparent that angiogenesis plays a pivotal role in endometriosis. This review focuses on a multitude of factors involved in the angiogenic phenotype of endometriosis demonstrating that many biological systems such as the immune system and steroid hormones are closely connected to angiogenic pathways in this disease. In addition, experimental and clinical data are discussed that concentrate on the inhibition of angiogenesis as a novel therapeutic approach for endometriosis.

Toward gene therapy of endometriosis: adenovirus-mediated delivery of dominant negative estrogen receptor genes inhibits cell proliferation, reduces cytokine production, and induces apoptosis of endometriotic cells

OBJECTIVE

To use dominant negative mutants of estrogen receptor genes delivered to endometriosis cells via an adenovirus vector (Ad-DN-ER) to abrogate estrogen action on these cells.

DESIGN

Experimental in vitro study.

SETTING

University research laboratory.

PATIENT(S)

Patients with ovarian endometriomas provided endometriotic cells, and patients with uterine prolapse or subserous leiomyoma provided control endometrial cells.

INTERVENTION(S)

Transfection of endometriotic cells by dominant negative estrogen receptor genes via adenovirus vector (Ad-DN-ER).

MAIN OUTCOME MEASURE(S)

The main outcome measures were cellular proliferation, cytokine production, and induction of apoptosis in endometriotic cells.

RESULT(S)

Coxsackievirus-adenovirus receptor mRNA expression and adenovirus transduction efficiency were significantly higher in endometriotic than normal endometrial cells. Ad-DN-ER-treated endometriotic cells, as compared with control virus-treated cells, showed cell rounding and detachment (cell death), a 72% reduction in the number of viable cells 5 days after transduction, significantly less production of monocyte chemotactic protein-1 (7.8 +/- 0.5 vs. 152.8 +/- 1.9 pg/mL, respectively), vascular endothelial growth factor (356.2 +/- 11.6 vs. 997.3 +/- 16.5 pg/mL, respectively), and interleukin-6 (268.7 +/- 2.6 vs. 414.5 +/- 3.6 pg/mL, respectively), and a significantly higher percentage of apoptotic cells (51.2 +/- 7.8 vs. 23.8 +/- 1.7, respectively).

CONCLUSION(S)

An adenovirus can effectively transfect endometriotic cells in vitro. The DN-ER delivered to endometriotic cells via an adenovirus decreases cell proliferation, induces apoptosis, and decreases cytokine production. Adenovirus-mediated gene therapy may represent a potential therapeutic option for endometriosis in the future.

In vitro and in vivo approaches to study angiogenesis in the pathophysiology and therapy of endometriosis

Endometriosis represents one of the most common gynaecological disorders. According to the implantation theory, angiogenesis is a major prerequisite for the initiation and progression of the disease. Thus, during the last decade, many studies have focused on the mechanisms regulating angiogenesis in endometriotic lesions. For this purpose, sophisticated in vitro and in vivo approaches have been established, which are highlighted in this review. Enzyme-linked immunosorbent assays demonstrate the imbalance of pro- and anti-angiogenic growth factors in isolated peritoneal fluid from endometriosis patients. Histological, immunohistochemical and gene expression analyses of endometriotic tissue provide detailed information on the angio-architecture of endometriotic lesions and the different growth factor expression by various cell populations. Moreover, cell culture systems are useful tools for the identification of hormonal and immunological factors involved in the angiogenic process. Finally, sophisticated in vivo models, such as rodent models of peritoneal endometriosis as well as the chorioallantoic membrane assay and the dorsal skinfold chamber, allow for the detailed analysis of blood vessel development in ectopic endometrium and the efficacy of angiogenesis inhibitors. The findings resulting from all these approaches will help to provide better insights into the pathophysiology of endometriosis and to establish new anti-angiogenic treatment strategies for the future.

Noninvasive and real-time assessment of reconstructed functional human endometrium in NOD/SCID/gamma c(null) immunodeficient mice

Human uterine endometrium exhibits unique properties of cyclical regeneration and remodeling throughout reproductive life and also is subject to endometriosis through ectopic implantation of retrogradely shed endometrial fragments during menstruation. Here we show that functional endometrium can be regenerated from singly dispersed human endometrial cells transplanted beneath the kidney capsule of NOD/SCID/gamma(c)(null) immunodeficient mice. In addition to the endometrium-like structure, hormone-dependent changes, including proliferation, differentiation, and tissue breakdown and shedding (menstruation), can be reproduced in the reconstructed endometrium, the blood to which is supplied predominantly by human vessels invading into the mouse kidney parenchyma. Furthermore, the hormone-dependent behavior of the endometrium regenerated from lentivirally engineered endometrial cells expressing a variant luciferase can be assessed noninvasively and quantitatively by in vivo bioluminescence imaging. These results indicate that singly dispersed endometrial cells have potential applications for tissue reconstitution, angiogenesis, and human-mouse chimeric vessel formation, providing implications for mechanisms underlying the physiological endometrial regeneration during the menstrual cycle and the establishment of endometriotic lesions. This animal system can be applied as the unique model of endometriosis or for other various types of neoplastic diseases with the capacity of noninvasive and real-time evaluation of the effect of therapeutic agents and gene targeting when the relevant cells are transplanted beneath the kidney capsule.

High-dose atorvastatin causes regression of endometriotic implants: a rat model

BACKGROUND

This prospective randomized-controlled animal study was designed to determine the effects of atorvastatin on experimentally induced endometriosis in a rat model.

METHODS

Thirty-seven Wistar-Albino rats in which endometriotic implants were induced were randomly divided into four groups. Group I (Low-dose atorvastatin group, eight rats) were given 0.5 mg kg(-1) day(-1) oral atorvastatin. Group II (High-dose atorvastatin group, 10 rats) were given 2.5 mg kg(-1) day(-1) oral atorvastatin. Group III were given a single dose of 1 mg kg(-1) s.c. leuprolide acetate (GnRH agonist group, nine rats). Group IV were given no medication and served as controls (10 rats). All rats received the treatment for 21 days and were then euthanized to assess the implants' size, vascular endothelial growth factor (VEGF) level in peritoneal fluid and histological score.

RESULTS

At the end of the treatment, the mean areas of implants were smaller and VEGF levels in peritoneal fluid were lower in Groups II and III than those in Group I and the control group (all P < 0.05). The mean areas of implants decreased from 41.2 +/- 13.9 to 22.7 +/- 13.9 mm(2) after medication in Group II and decreased from 41.2 +/- 18.1 to 13.1 +/- 13.8 mm(2) in Group III (both P < 0.05), whereas in Group I, the mean area increased from 43.0 +/- 12.7 to 50.5 +/- 13.9 mm(2) (P < 0.05).

CONCLUSIONS

High-dose atorvastatin caused a significant regression of endometriotic implants.

Activation of mammalian target of rapamycin in postmenopausal ovarian endometriosis

The purpose of this study was to determine whether Akt and mammalian target of rapamycin (mTOR), downstream targets of phosphatidylinositol 3-kinase, are activated in endometriosis and ovarian cancer specimens. We measured total and phosphorylated levels of Akt and mTOR from 17 frozen ovarian cancers and 15 benign endometriosis specimens (nine from premenopausal women and six from postmenopausal women) by quantitation of signals from western blots using antibodies against these proteins. Elevated phospho-Akt was detected in ovarian cancer versus endometriosis specimens from premenopausal women and endometriosis specimens from postmenopausal women (2.3 +/- 0.45 versus 0.10 +/- 0.06 and 0.17 +/- 0.11; P < 0.05) when the western blot signal of activated kinase was normalized to total kinase levels. Elevated phospho-mTOR was detected in ovarian cancer and postmenopausal endometriosis versus premenopausal endometriosis (0.52 +/- 0.19 and 0.46 +/- 0.29 versus 0.13 +/- 0.08; P < 0.05). Expression of total kinases (normalized to beta-actin) was higher in carcinoma versus endometriosis specimens. Elevation of the active mTOR was specifically detected in postmenopausal endometriosis.

FR 167653, a p38 mitogen-activated protein kinase inhibitor, suppresses the development of endometriosis in a murine model

In various cells including endometriotic cells, p38 mitogen-activated protein kinase (MAPK) plays essential roles for inflammation, an etiological factor for endometriosis. We evaluated the effect of FR 167653, a p38 MAPK inhibitor, on the development of endometriosis using a murine model. As an endometriosis model, estradiol-treated ovariectomized BALB/c mice were injected intraperitoneally with endometrial fragments of the syngenic donor mice. The animals were injected with either 30mg/kg FR 167653 or only vehicle (control) s.c. twice a day, starting 2 days before endometrial injection. Three weeks later, the peritoneal fluids and the developed endometriotic lesions were collected. Both the weight of all the endometriotic lesions per mouse and the concentrations of interleukin-6 and monocyte chemoattractant protein-1 in the peritoneal fluid were significantly lower in the FR 167653-treated mice than in the control mice. These findings suggest that FR 167653 may inhibit the development of endometriosis possibly by suppressing peritoneal inflammatory status.

Gene Transfer Approaches for Gynecological Diseases

Gene transfer presents a potentially useful approach for the treatment of diseases refractory to conventional therapies. Various preclinical and clinical strategies have been explored for treatment of gynecological diseases. Given the direst need for novel treatments, much of the work has been performed with gynecological cancers and ovarian cancer in particular. Although the safety of many approaches has been demonstrated in early phase clinical trials, efficacy has been mostly limited so far. Major challenges include improving gene transfer vectors for enhanced and selective delivery and achieving effective penetration and spread within advanced and complex tumor masses. This review will focus on current and developmental gene transfer applications for gynecological diseases.

A novel noninvasive model of endometriosis for monitoring the efficacy of antiangiogenic therapy

Endometriosis, the presence of ectopic endometrial tissue, is a common disease associated with high morbidity and socioeconomic problems. Angiogenesis, the formation of new blood vessels, plays an important role in the formation and growth of endometriotic lesions. We have created a novel, noninvasive model to monitor the growth of these lesions and the associated angiogenesis in vivo. First, we generated luciferase-expressing transgenic mice by inserting the human ubiquitin C promoter coupled to the firefly luciferase reporter. Injection of luciferin in these mice causes full-body bioluminescence, which can be detected using a low-light CCD camera. Endometrial tissue from these transgenic mice was surgically implanted into nonluminescent recipients. Bioluminescence of lesions was noninvasively imaged after intravenous or intraperitoneal injection of luciferin. Transabdominal luminescence compared well with the location of the transgenic endometriotic lesions, and lesion size correlated with the intensity of luminescence. Systemic treatment with the angiogenesis inhibitors caplostatin and endostatin peptide mP-1 delayed and suppressed the onset and intensity of the luminescent signal. Caplostatin suppressed the growth of endometriotic lesions by 59% compared with controls. This novel, noninvasive model of endometriosis provides a means to study early angiogenesis in vivo and to monitor endometriotic growth and the efficacy of systemic antiangiogenic therapy.

Endostatin inhibits the growth of endometriotic lesions but does not affect fertility

OBJECTIVE

To determine whether endometriosis can be treated with the angiogenesis inhibitor endostatin and the effect of this treatment on fertility and reproduction.

DESIGN

Pharmacologic intervention in a surgically induced model of endometriosis and in female mice undergoing mating.

SETTING

Animal research facility.

ANIMAL(S)

Eight-week-old, female C57BL/6 and SCID mice.

INTERVENTION(S)

After implantation of autologous endometrium, mice received endostatin or the vehicle-matched control for 4 weeks. For the reproductive function study, mice receiving endostatin or vehicle were mated and reproductive functions were observed.

MAIN OUTCOME MEASURE(S)

Growth of endometriotic lesions after 4 weeks of treatment; estrous cycling, corpus luteum formation, serum hormone levels, and mating time as fertility measures; and pregnancy rates, length of pregnancy, fetal vitality, number, and outcome of litter as reproductive measures.

RESULT(S)

Endostatin suppressed the growth of endometriotic lesions by 47% compared with controls. Estrous cycling and corpus luteum formation were normal in both groups. Female mice receiving endostatin were as fertile as mice receiving vehicle, had normal pregnancies, and delivered the same number of pups. The offspring were healthy without teratogenic stigmata and reproduced normally themselves.

CONCLUSION(S)

Antiangiogenic therapy with endostatin may present a promising novel, nontoxic therapeutic option for patients with endometriosis.

Short synthetic endostatin peptides inhibit endothelial migration in vitro and endometriosis in a mouse model

OBJECTIVE

To determine the active peptide regions inside the angiogenesis inhibitor endostatin that can inhibit endothelial migration in vitro and also inhibit endometriosis in a mouse model.

DESIGN

Pharmacologic intervention in a surgically induced mouse model of endometriosis and endothelial migration assay.

SETTING

Animal research and laboratory facility.

SUBJECT(S)

Eight-week-old, female C57BL/6 mice and human microvascular endothelial cells.

INTERVENTION(S)

Eight overlapping synthetic peptides were tested for inhibitory potential on endothelial migration in vitro. The peptides with significant activity then were given for 4 weeks to mice after implantation of autologous endometrium.

MAIN OUTCOME MEASURE(S)

Inhibition of vascular endothelial growth factor-induced endothelial migration for in vitro studies. In vivo studies examined the growth rate of endometriotic lesions after 4 weeks of treatment, as well as the effect on estrous cycling and ovulation as assessed by corpus luteum formation.

RESULT(S)

The N-terminal mP-1 peptide and the internal mP-6 peptide inhibited endothelial migration in a dose-dependent manner. Additionally, both synthetic peptides suppressed growth of endometriotic lesions significantly in vivo. However, estrous cycling and corpus luteum formation were normal in both groups.

CONCLUSION(S)

Short endostatin fragments may be promising as a new, nontoxic therapeutic strategy for the treatment of endometriosis without inhibition of normal estrous cycles.

A baboon model for endometriosis: implications for fertility

Endometriosis is one of the most common causes of chronic pelvic pain and infertility in women in the reproductive age group. Although the existence of this disease has been known for over 100 years our current knowledge of its pathogenesis and the pathophysiology of its related infertility remains unclear. Several reasons contribute to our lack of knowledge, the most critical being the difficulty in carrying out objective long-term studies in women. Thus, we and others have developed a model of this disease in the non-human primate, the baboon (Papio anubis). Intraperitoneal inoculation of autologous menstrual endometrium results in the development of endometriotic lesions with gross morphological characteristics similar to those seen in the human. Multiple factors have been implicated in endometriosis-associated infertility. We have described aberrant levels of factors involved in multiple pathways important in the establishment of pregnancy, in the endometrium of baboons induced with endometriosis. Specifically, we have observed dysregulation of proteins involved in invasion, angiogenesis, methylation, cell growth, immunomodulation, and steroid hormone action. These data suggest that, in an induced model of endometriosis in the baboon, an increased angiogenic capacity, decreased apoptotic potential, progesterone resistance, estrogen hyper-responsiveness, and an inability to respond appropriately to embryonic signals contribute to the reduced fecundity associated with this disease.

Quantification of endometriotic lesions in a murine model by fluorimetric and morphometric analyses

BACKGROUND

In animal models of endometriosis, the identification and quantification of lesions originating from human endometrium is often hampered by the small size of the implants and their embedding in murine tissue. The purpose of the present study was to develop two new methods of quantifying endometriosis-like lesions in a nude mouse model: fluorimetry and morphometry.

METHODS

Human menstrual endometrium was labelled using a fluorescent tracker, carboxyfluorescein diacetate, succinimidyl ester (CFDA-SE), and transplanted into the pelvic cavity of mice by injection through the peritoneum after performing a cutaneous incision. After 5 days, lesions were recovered by laparotomy. The fluorescence of the recovered endometriotic lesions was measured. Endometrial stroma and glands were immunostained in lesion sections with anti-CD10 and anti-CK22 antibodies, and their surface area was evaluated by morphometric analysis.

RESULTS

Fluorescent labelling allows identification of lesions not visible macroscopically. A good correlation was observed between fluorimetry and morphometry (r=0.88) applied for lesion quantification.

CONCLUSIONS

Fluorimetric evaluation combined with morphometric analysis of endometriosis-like lesions allows objective and reliable recording of endometriosis development in a nude mouse model. This quantification method could therefore be useful for future pharmacological and toxicological studies.

Vascular development in endometriosis

Endometriosis, defined as the presence of endometrial tissue outside the uterus, is an estrogen-dependent disease which causes pelvic pain and subfertility in women of reproductive age. The condition has a dramatic impact on the professional, social and marital life of sufferers. Direct and indirect evidence suggests that angiogenesis is required for the development and persistence of endometriosis. In this review the state-of-the-art with regard to our understanding of the role of angiogenesis in the ectopic implantation and survival of menstrual endometrial tissue will be discussed.

Time course of pelvic endometriotic lesion revascularization in a nude mouse model

OBJECTIVE

To assess the timing of endometrial lesion revascularization in a murine model.

DESIGN

Prospective experimental study.

SETTING

An academic research environment.

ANIMAL(S)

Twenty-six nude mice.

INTERVENTION(S)

Endometriosis was induced in mice by intraperitoneal deposition of human menstrual endometrium. Endometrial implants were recovered on days 1, 3, 5, 8, 10, 15, and 21 after implantation.

MAIN OUTCOME MEASURE(S)

Sections from the endometrial implants were immunostained with species-specific antiplatelet endothelial cell adhesion molecule-1 (PECAM-1) antibodies and vessels of murine and human origin were counted.

RESULT(S)

Endothelial cells of human origin in the implant progressively disappeared between day 3 and day 10. Seventy-eight percent of the vessel sections were positive for human PECAM-1 on day 5, 40.1% on day 8, and only 14.1% on day 10. However, there was a marked increase in murine PECAM-1-expressing vessels in endometrial stroma between day 5 (1.4%) and day 8 (68.0%), 10 (69.5%), and 15 (87.2%).

CONCLUSION(S)

Our study demonstrates that PECAM-1 is a reliable endothelial cell marker to evaluate the role of angiogenesis in the nude mouse model. It also indicates that revascularization of human endometrial implants occurs between 5 and 8 days after implantation and involves the disappearance of native graft vessels, coinciding with the invasion of the interface and then the stroma by murine vessels.

Angiostatic agents prevent the development of endometriosis-like lesions in the chicken chorioallantoic membrane

A prospective study was performed to determine the effects of the angiostatic compounds anti-hVEGF antibody, TNP-470, endostatin, and anginex on the vascularization and on endometriosis-like lesion formation in the chicken chorioallantoic membrane model. Endometriosis-like lesion formation was significantly impaired after treatment with angiostatic agents, which was associated with decreased vessel densities in the surrounding chorioallantoic membrane and more necrosis in the endometriosis-like lesions.

Nonsteroidal antiinflammatory drugs differentially suppress endometriosis in a murine model

OBJECTIVE

To determine whether nonsteroidal antiinflammatory drugs (NSAIDs) affect the establishment and progression of endometriotic lesions in a murine model.

DESIGN

Pharmacologic intervention in a surgically induced murine model of abdominal/peritoneal endometriosis.

SETTING

Animal research facility.

PATIENT(S)

Eight-week-old, female C57BL/6 mice.

INTERVENTION(S)

After implantation of autologous endometrium, mice were randomized into groups and treated with one of several NSAIDs or the vehicle-matched control for 4 weeks.

MAIN OUTCOME MEASURE(S)

Establishment, growth, and total burden of endometriotic lesions.

RESULT(S)

The NSAIDs differentially inhibited lesion establishment and growth, resulting in significantly reduced disease burden. Compared with controls (5.7 +/- 2.3 mm(2)), lesion burden was reduced by celecoxib (1.3 +/- 1.2 mm(2)), indomethacin (1.4 +/- 1.4 mm(2)), naproxen (2.7 +/- 1.2 mm(2)), sulindac (3.1 +/- 1.5 mm(2)), rofecoxib (3.4 +/- 3.0 mm(2)), and ibuprofen (4.1 +/- 1.4 mm(2)). In contrast, aspirin (5.9 +/- 1.2 mm(2)) had no statistically significant effect. Uninterrupted estrus cycling was confirmed by vaginal exams and smears in celecoxib-treated mice.

CONCLUSION(S)

Chronic administration of certain NSAIDs limits the progression of endometriosis in this murine model. The data suggest that NSAID selection in the treatment of endometriosis should be extended beyond pain management to maximize the inhibitory effect on disease burden.

Quantitative assessment of human endometriotic tissue maintenance and regression in a noninvasive mouse model of endometriosis

Endometriosis is a prevalent disease characterized by the estrogen-dependent ectopic growth of endometrial tissue. Most of the current medical therapies consist in inducing a hypoestrogenic state in patients, but these treatments are associated with severe side effects and high recurrence rates. The development of convenient and reliable endometriosis animal models would be instrumental to accelerate the emergence of new therapeutic alternatives. Recently, we developed an improved experimental model for endometriosis, relying on the infection of human endometrial fragments by an adenovirus carrying the green fluorescent protein. Following injection of fluorescent fragments into nude mice, the implantation and growth of endometriotic-like lesions could be followed noninvasively. In the present work, we demonstrate that this model can be used to quantify the size of fluorescent endometriotic lesions by in vivo imaging. To this end, we repeatedly measured lesion size over a 4-week period in mice supplemented or not with estradiol. The model was adequate to confirm previous results showing that estrogen is dispensable for the implantation phase of endometrial tissue, whereas it is required for lesion maintenance. As a proof of concept for inducing regression of established lesions, ganciclovir was used to treat animals implanted with human fluorescent endometrial fragments expressing thymidine kinase. A significant decrease in lesion size was observed by in vivo imaging in ganciclovir-treated mice. Together, the data indicate that the noninvasive animal model described here provides a tool for drug testing and/or gene target validation in endometriosis.

Distinct roles for the alpha and beta subunits in the functions of integrin alphaMbeta2

Integrin alphaMbeta2 (Mac-1, CD11b/CD18) is a noncovalently linked heterodimer of alphaM and beta2 subunits on the surface of leukocytes, where it plays a pivotal role in the adhesion and migration of these cells. Using HEK293 cells expressing alphaMbeta2 or the individual constituent chains on their surface, we analyzed the contributions of the alphaM or beta2 subunits to functional responses mediated by the integrin. In cells expressing only alphaM or beta2, the individual subunits were not associated with the endogenous integrins of the cells, and other partners for the subunits were not detected by surface labeling and immunoprecipitation under a variety of conditions. The alphaM cells mediated adhesion and spreading on a series of alphaMbeta2 ligands (fibrinogen, Factor X, iC3b, ICAM-1 (intercellular adhesion molecule-1), and denatured ovalbumin) but could not support cell migration to any of these. The spreading of the alphaM cells suggested an unanticipated linkage of this subunit to the cytoskeleton. The beta2 cells supported migration and attachment but not spreading on a subset of the alphaMbeta2 ligands. The heterodimeric receptor and its individual subunits were purified from the cells by affinity chromatography and recapitulated the ligand binding properties of the corresponding cell lines. These data indicate that each subunit of alphaMbeta2 contributes distinct properties to alphaMbeta2 and that, in most but not all cases, the response of the integrin is a composite of the functions of its individual subunits.

Elevated angiogenin levels in the peritoneal fluid of women with endometriosis correlate with the extent of the disorder

OBJECTIVE

To assess the release of angiogenin into peritoneal fluid in women with and without endometriosis by measuring its concentration with reference to disease stage, presence of red lesions, and phase of the menstrual cycle.

DESIGN

Retrospective study.

SETTING

Nagoya City University Hospital.

PATIENT(S)

Sixty-four women with endometriosis (n = 38) and cystadenomas (n = 26) for whom surgery was scheduled in the proliferative or secretory phase of the menstrual cycle.

INTERVENTION(S)

Peritoneal fluid samples were obtained at laparotomy or laparoscopy.

MAIN OUTCOME MEASURE(S)

Angiogenin concentrations in the peritoneal fluid, as measured by ELISA.

RESULT(S)

Angiogenin concentration in the peritoneal fluid was markedly elevated in the endometriosis patients (median 515 ng/mL, interquartile range 151-1763 ng/mL) compared with the cystadenoma (control) patients (195 ng/mL, 98-324 ng/mL), with values correlating with the extent of the disease. No significant differences between the proliferative phase and the secretory phase were observed in either the controls or the endometriosis patients.

CONCLUSION(S)

The inflammation associated with endometriosis, through increasing levels of peritoneal fluid angiogenin, might promote angiogenesis for progression of the disease and correlate with the extent of the disorder.

Endometriosis and the neoplastic process

Endometriosis is a frequent disorder that commonly presents with infertility and pelvic pain. Although the precise aetiology of endometriosis is unclear, it is generally considered to involve multiple genetic, environmental, immunological, angiogenic and endocrine processes. Genetic factors have been implicated in endometriosis but the susceptibility genes remain largely unknown. Although endometriosis is a benign disorder, recent studies of endometriosis suggest endometriosis could be viewed as a neoplastic process. Evidence to support this hypothesis includes the increased susceptibility to develop ovarian clear-cell and endometrioid cancers in the presence of endometriosis, and molecular similarities between endometriosis and cancer. In this article we discuss (i) the evidence suggesting that endometriosis might be viewed as a neoplastic process, and (ii) the implications of this hypothesis for elucidating the pathogenesis of endometriosis and developing novel methods of diagnostic classification and individualised treatments.

Molecular biology and gene therapy in the treatment of chronic pain

Technologic advancements have made cell type-specific targeting, expression control, and safe and stable gene transfer possible. Animal research has provided increasing experience with gene transfer to the nervous system and sensory neurons in particular. Gene-based neuromodultion can be achieved through neuronal delivery of transgenes capable of altering synaptic function. Alternatively, ex vivo gene transfer can be used to create cell lines capable of secreting analgesic neurepeptides. Translatation of these grafts and direct gene-based neuromoduation can be applied to the control of pain and the root causes of pain. These approaches combine anatomic and pharmacologic specificity. As the technology continues to improve, clinical application of cellular and molecular pain control is likely.