Endometriosis In Baboons Research Articles

Effects of endometriosis on immunity and mucosal microbial community dynamics in female olive baboons

Endometriosis is defined as the growth of endometrial tissue in ectopic locations, and is associated with altered immune and microbial phenotypes. It is unclear if these changes are the result of the disease or may be causative. We induced endometriosis in non-human primates (Papio Anubis) to test our hypothesis that the growth of endometriotic lesions results in alterations in immune and microbial dynamics that may advance disease progression. Baboon samples were collected pre-inoculation (prior to disease induction), at 3, 6, 9, and 15 months after disease induction. Tolerant regulatory T-cells (Tregs) and inflammatory T-helper 17 (Th17) cells were identified in peripheral blood and within the eutopic/ectopic endometrial tissues. Microbiome communities were identified in fecal/urine samples. The induction of endometriosis decreased peripheral Tregs cells while Th17 cells increased at all post-induction collections, thus reducing the Tregs:Th17 cells ratio, indicating systemic inflammation. Microbiome diversity and abundance were altered at each sample site after disease induction. Thus, induction of endometriosis in baboons caused an immune shift toward an inflammatory profile and altered mucosal microbial profiles, which may drive inflammation through production of inflammatory mediators. Immune and microbial profiling may lead to innovative diagnostic tools and novel therapies for endometriosis treatment.

Effect of simvastatin on baboon endometriosis.

Endometriosis, a common disorder affecting women of reproductive age, is characterized by ectopic growth of the endometrial tissues, altered steroid hormone response, and inflammation. Previous studies revealed that statins, selective inhibitors of the key step of mevalonate pathway, inhibit growth of endometrial stromal cells in vitro and reduce endometriotic lesions in murine models of endometriosis. This study evaluated the effects of simvastatin on the development of endometriosis in a baboon model of this disease. Sixteen baboons were randomly assigned to the treatment group (simvastatin, 20 mg daily) or to the control group. Endometriotic lesions were evaluated by laparoscopy after 3 months. The volume of red, orange-red, and white endometriotic lesions was significantly reduced by 78% in animals treated with simvastatin. The expression of a marker of proliferation, proliferating cell nuclear antigen (PCNA), was significantly reduced in animals receiving simvastatin in red lesions, white lesions, black lesions, and in adhesions. Simvastatin was also associated with an increase in the expression of estrogen receptor alpha in red lesions, and a decrease in the expression of estrogen receptor beta in black lesions, in adhesions, and in eutopic endometrium. Furthermore, simvastatin significantly reduced the expression of neopterin, a marker of inflammation, oxidative stress, and immune system activation. Collectively, the present findings indicate that the inhibition of the mevalonate pathway by simvastatin reduces the risk of developing endometriosis in the primate model of this disease by decreasing the growth of endometrial lesions, by modulating the expression of genes encoding for estrogen receptors, and by reducing inflammation.

An efficient model of human endometriosis by induced unopposed estrogenicity in baboons.

Endometriosis is a chronic estrogen-dependent disease that occurs in approximately 10% of reproductive age women. Baboons offer a clear benefit for studying the initiation and progression of endometriosis since baboon is very close to humans phylogenetically. Progestins are used in the treatment of endometriosis. The therapeutic window of progestins depends on the ratio of its affinity towards progesterone receptor agonism verses antagonism. The present study is to determine the role of pure antiprogestin in baboon endometriosis. We hypothesize that pure antiprogestin will induce unopposed estrogenicity and spontaneous endometriosis in baboons. The rate of endometrial invasion and attachment through modeled peritoneum in the presence and absence of progesterone and antiprogestin was evaluated in this study. A baboon model of endometriosis induced by unopposed estrogenicity using progesterone receptor antagonist (EC304) was used in this study. We observed EC304 has induced unopposed estrogenicity that deregulated proteins involved in attachment, invasion, cell growth, and steroid hormone receptors in this model. Our data suggest that depleting progesterone levels in the endometrium will increase estrogen hyper-responsiveness that leads to increased endometriotic lesion progression in the baboon (Papio anubis) model. This study reports a refined model of human endometriosis in baboons that could potentially be used to develop new diagnostic and therapeutic strategies for the benefit of women suffering from endometriosis.

C-Jun NH2-terminal kinase inhibitor bentamapimod reduces induced endometriosis in baboons: an assessor-blind placebo-controlled randomized study

To test the hypothesis that the c-Jun NH2-terminal kinase (JNK) inhibitor (JNKI) bentamapimod (AS602801/PGL5001) can reduce induced endometriosis in baboons. Prospective randomized placebo-controlled study. Nonhuman primate research center. Twenty baboons each underwent four laparoscopies. Initial screening laparoscopy (L1) was followed after one rest cycle by an endometriosis-induction laparoscopy (L2). Fifty days after L2, the baboons were randomized just before staging laparoscopy (L3). Treatment lasted for 60 days, followed by a post-treatment staging laparoscopy (L4). Randomization before a 60-day treatment in four groups: daily placebo (n = 5), daily oral administration of 20 mg/kg JNKI (n = 5), concomitant daily oral administration of 20 mg/kg JNKI and 10 mg medroxyprogesterone acetate (MPA; n = 5), or subcutaneous administration of 3 mg cetrorelix every 3 days (n = 5). Type, surface area and volume of endometriotic lesions, and revised American Society for Reproductive Medicine score and stage were recorded during L3 and L4. Menstrual cycle length and serum hormonal concentration were recorded before and after treatment. Compared with placebo, treatment with JNKI, JNKI + PMA, or cetrorelix resulted in lower total surface area and volume of endometriotic lesions. Remodeling of red active lesions into white lesions was observed more frequently in baboons treated with JNKI + MPA than in baboons treated with JNKI only. Menstrual cycle length and serum hormonal concentration were similar between placebo and JNKI groups. JNKI alone was as effective as JNKI + MPA or cetrorelix in reducing induced endometriosis in baboons, but without severe side effects or effect on cycle length or serum reproductive hormones.

Arginine methyltransferases mediate an epigenetic ovarian response to endometriosis.

Endometriosis is associated with infertility and debilitating chronic pain. Abnormal epigenetic modifications in the human endometrium have recently been implicated in the pathogenesis of this condition. However, whether an altered epigenetic landscape contributes to pathological changes in the ovary is unknown. Using an established baboon endometriosis model, early-, and late-stage epigenetic changes in the ovary were investigated. Transcript profiling of key chromatin-modifying enzymes using pathway-focused PCR arrays on ovarian tissue from healthy control animals and at 3 and 15 months of endometriosis revealed dramatic changes in gene expression in a disease duration-dependent manner. Ingenuity Pathway Analysis indicated that transcripts for chromatin-remodeling enzymes associated with reproductive system disease and cancer development were abnormally regulated, most prominently the arginine methyltransferases CARM1, PRMT2, and PRMT8. Downregulation of CARM1 protein expression was also detected in the ovary, fully-grown oocytes and eutopic endometrium following 15 months of endometriosis. Sodium bisulfite sequencing revealed DNA hypermethylation within the PRMT8 promoter, suggesting that deregulated CpG methylation may play a role in transcriptional repression of this gene. These results demonstrate that endometriosis is associated with changes of epigenetic profiles in the primate ovary and suggest that arginine methyltransferases play a prominent role in mediating the ovarian response to endometriosis. Owing to the critical role of CARM1 in nuclear receptor-mediated transcription and maintenance of pluripotency in the cleavage stage embryo, our results suggest that epigenetic alterations in the ovary may have functional consequences for oocyte quality and the etiology of infertility associated with endometriosis.

Aromatase inhibitor treatment limits progression of peritoneal endometriosis in baboons

To determine the effect of inhibiting aromatase activity on endometrial lesion growth and aromatase expression in a baboon model of induced endometriosis. Prospective study. Primate research institute. Sixteen olive baboons. Sixteen olive baboons with induced endometriosis were examined with laparoscopy 10 months after disease inoculation. Animals in group 1 (n = 10) were treated with 1.25 mg/d of the aromatase inhibitor (AI) letrozole, and animals in group 2 (n = 6) were given a placebo for a total of 6 months. Total number of endometriotic lesions, morphology, and volume of lesions, as well as semiquantitative reverse transcription-polymerase chain reaction and quantitative polymerase chain reaction for levels of aromatase cytochrome messenger RNA were measured. Ovarian volumes were evaluated before treatment initiation and every 2 months during the study. Treatment of group 1 animals with an AI significantly decreased lesion volume from baseline measurements, whereas the placebo-treated animals showed an increase in lesion volume. Aromatase messenger RNA levels in lesions in the AI-treated animals were significantly lower compared with the placebo-treated animals. Ovarian volumes were significantly increased at 6 months of AI treatment compared with pretreatment volumes. These findings suggest that suppression of aromatase cytochrome P450 may inhibit the invivo growth of endometriotic lesions in baboons.

Pleuro‐pulmonary endometriosis in baboons (Papio spp.): insights into pathogenesis

Human pleuro-pulmonary endometriosis (PPE) is rare. Recently, we identified several cases of abdominal endometriosis in baboons that developed PPE. Ten cases of PPE and four of intra-abdominal endometriosis (three simultaneous) were identified at necropsy in baboons (Papio spp.) found dead due to natural causes. The endometriotic lesions were evaluated using immunohistochemistry. The stromal (CD10+) and epithelial cells in intra-abdominal cases were estrogen and progesterone receptor (ER/PR) positive and thyroid transcription factor 1 (TTF-1) negative similar to that seen in humans. In contrast, the PPE cases displayed TTF-1-positive epithelium lining the cystic spaces, while the stroma was ER/PR positive similar to that in abdominal endometriosis. Both lymph nodes and spindle cell rests in lung interstitium contained ER/PR-positive stromal cells. The lung lesions were different from the abdominal lesions in having a TTF-1-positive lining epithelium. The deep pulmonary interstitial and lymph node endometrial stromal rests probably arrive via lymphatic route. The endometrial stroma is the driving force in PPE upon which the lung-specific epithelium condenses and may require a novel approach to therapy.

Induction of endometriotic nodules in an experimental baboon model mimicking human deep nodular lesions

To establish an experimental model for the study of deep nodular endometriosis. Induction of nodular endometriosis in baboons by grafting different uterine specimens to the peritoneal cavity. Research and university facilities. Ten baboons, to develop a model of induced deep nodular endometriosis. Biopsies of endometrium, and endometrium plus the junctional zone (JZ), full uterine thickness, and myometrium grafted to the peritoneum. Macroscopic descriptions recorded for observed induced lesions; staining with hematoxylin and eosin for histological evaluation and specific antibodies (CK22, CD10) for immunohistochemical studies; and analysis of surface area and volume of lesions, glandular density, and invasion of surrounding organs. The incidence of induced nodular endometriosis was 100%, but the extent depended on the tissue grafted. Lesions induced after grafting specimens containing the JZ were statistically significantly larger than those not containing the JZ. Surrounding organ invasion was reported in more than 40% of lesions after grafting specimens containing the JZ. The first experimental model of nodular endometriosis allows investigation of deeper nodular lesions as well as invasion phenomena associated with nodular lesions.

Is the baboon model appropriate for endometriosis studies?

To determinethe prevalence of spontaneous endometriosis andthe incidence of induced endometriosis after endocervical canal resection in baboons. Induction and follow-up of endometriosis in baboons, which is one of the primate species that develop spontaneous endometriosis. Forty-one baboons were checked for the presence of spontaneous endometriosis. We then attempted to induce endometriosis in 30 of them by endocervical canal resection. Institute of Primate Research, Nairobi, Kenya, and Catholic University of Louvain, Brussels, Belgium. Forty-one baboons were checked for spontaneous endometriosis and 30 of them were used to develop a model of induced endometriosis. A total of 41 baboons underwent diagnostic laparoscopy for 10 months. In a first step, 30 of this number subsequently underwent endocervical canal resection. In a second step, 20 of the 30 underwent uterine horn resection. Follow-up by laparoscopy. Two of the 41 baboons were diagnosed with spontaneous endometriosis (4.8%). Twelve months after the surgical procedure to induce endometriosis, 8 of 29 animals presented with endometriotic lesions diagnosed by using laparoscopy and confirmed by histologic examination. The incidence of induced endometriosis in our model was thus 27.6%. In 2 baboons, endometriosis disappeared over time, resulting in a final rate of 20.7% (6/29). The rate of spontaneous endometriosis is very low (4.8%). Endometriosis can be induced (with a rate of just 27.6%) by endocervical canal resection to stimulate retrograde menstruation.

Peroxisome proliferator-activated receptor-(gamma) receptor ligand partially prevents the development of endometrial explants in baboons: a prospective, randomized, placebo-controlled study.

A prospective, randomized, placebo-controlled study was conducted in a baboon model to determine if a thiazolidinedione agonist of peroxisome proliferator-activated receptor-gamma, pioglitazone, can impede the development of endometriosis. Endometriosis was induced using laparoscopic, intrapelvic injection of eutopic menstrual endometrium, previously incubated with placebo or pioglitazone for 30 min, in 12 female baboons with a normal pelvis that had undergone at least one menstrual cycle since the time of captivity. At this point, the 12 baboons were randomized into two groups and treated from the day of induction. They received either PBS tablets (n = 6, placebo control, placebo tablets once a day by mouth) or pioglitazone (n = 6, test drug, 7.5 mg by mouth each day). A second and final laparoscopy was performed in the baboons to record the extent of endometriotic lesions between 24 and 42 d after induction (no difference in length of treatment between the two groups, P = 0.38). A videolaparoscopy was performed to document the number and surface area of endometriotic lesions. The surface area and volume of endometriotic lesions were significantly lower in pioglitazone treated baboons than the placebo group (surface area, 48.6 vs. 159.0 mm(2), respectively, P = 0.049; vol, 23.7 vs. 131.8 mm(3), respectively, P = 0.041). The surface area (3.5 vs. 17.8 mm(2), P = 0.017, pioglizatone vs. placebo) and overall number (1.5 vs. 9.5, P = 0.007, pioglizatone vs. placebo) of red lesions were lower in the pioglitazone group. A peroxisome proliferator-activated receptor-gamma ligand, pioglitazone, effectively reduced the initiation of endometriotic disease in the baboon endometriosis model. Using this animal model, we have shown that thiazolidinedione is a promising drug for preventive treatment of endometriosis.

Immunohistochemical study of the ubiquitin - nuclear factor-ΚB pathway in the endometrium of the baboon (Papio anubis) with and without endometriosis

The aim of the present study was to conduct a semiquantitative immunohistochemical investigation into the levels of intermediary proteins within the nuclear factor (NF)-kappaB pathway throughout the menstrual cycle in a non-human primate, namely the baboon (Papio anubis), with and without endometriosis. Formalin-fixed eutopic (n = 2-4) and ectopic (n = 6-7) endometrial tissues from baboons at the mid-luteal phase were embedded in paraffin and examined for NF-kappaB pathway components (i.e. IkappaB kinase (IKK) alpha, IKKbeta, phosphorylated (phospho-) IkappaBalpha and phospho-NF-kappaB p65 subunit), ubiquitin, 19S proteasome and the NF-kappaB activator tumour necrosis factor (TNF)-alpha. Similarly, endometrial tissues from baboons at the late follicular, mid-luteal and menses phase (n = 2-4) were investigated to determine the levels of these proteins throughout the menstrual cycle. Cytoplasmic stromal IKKalpha and glandular 19S proteasome immunostaining was elevated in the ectopic endometrium, whereas levels of ubiquitin, phospho-p65, IKKbeta, TNF-alpha and nuclear 19S proteasome were similar in the eutopic and ectopic endometrium. A significant decrease in phospho-IkappaBalpha nuclear immunostaining was observed within glandular cells of the ectopic endometrium. In the eutopic endometrium, IKKalpha, ubiquitin and 19S proteasome immunostaining was elevated in different phases of the menstrual cycle, whereas levels of phospho-p65, IKKbeta, phospho-IkappaBalpha and TNF-alpha remained unchanged. We have demonstrated that, in the baboon endometriosis model, levels of IKKalpha immunostaining are elevated, whereas those of phospho-IkappaBalpha are reduced, consistent with the hypothesis that excessive NF-kappaB activity plays a role in reducing ectopic endometrial apoptosis, which contributes to the pathophysiology of endometriosis. Further studies are required to confirm a causal association between elevated IKKalpha levels and reduced endometrial apoptosis.

The effect of JNK-inhibitors on endometriosis in baboons with induced disease: a placebo-controlled randomized study

OBJECTIVE: To test the hypothesis that the c-Jun NH2-terminal Kinases (JNKs) inhibitors can reduce the endometriotic activity in a baboon model with established endometriosis.DESIGN: Prospective randomized, placebo-controlled study in nonhuman primates.MATERIALS AND METHODS: Laparoscopic induction of endometriosis was performed in 20 baboons using intrapelvic seeding of menstrual endometrium inside the pelvic cavity. Fifty days later, a pretreatment videolaparoscopy (baseline disease assessment) was performed. The type, surface area and volume of endometriotic lesions (typical, red, white, or suspicious) were recorded and the revised ASRM score and stage were calculated. Baboons were then randomized into 4 groups and treated for a total duration of 60 days. They received banana (placebo, n=5), 20 mg/kg JNK inhibitor orally (n=5), JNK Inhibitor + 10mg Medroxy progesterone acetate (MPA) orally (n=5), Cetrorelix acetate (GnRH antagonist) 3 mg every three days subcutaneously (n=5). A posttreatment videolaparoscopy was performed to compare the extent of endometriosis in the 4 groups. Data were analysed with nonparametric statistics.RESULTS: In contrast with the placebo group, baboons treated with JNK Inhibitor, with JNK Inhibitor + MPA, or with Cetrorelix all showed a statistically significant reduction of the total surface area (p=<0.05) and volume (P=<0.05) of endometriotic lesions after treatment when compared to their pelvic status before treatment. These data were confirmed when red lesions were analyzed separately. Remodelling of red active lesions into white lesions was observed more frequently (p=<0.05) in baboons treated with the combination of JNK inhibitor and MPA than in baboons treated with placebo.CONCLUSIONS: JNK inhibitors effectively diminish the burden of endometriosis disease in a baboon model with induced endometriosis. The addition of MPA to JNK inhibitors may favor the healing process of endometriotic lesions. OBJECTIVE: To test the hypothesis that the c-Jun NH2-terminal Kinases (JNKs) inhibitors can reduce the endometriotic activity in a baboon model with established endometriosis. DESIGN: Prospective randomized, placebo-controlled study in nonhuman primates. MATERIALS AND METHODS: Laparoscopic induction of endometriosis was performed in 20 baboons using intrapelvic seeding of menstrual endometrium inside the pelvic cavity. Fifty days later, a pretreatment videolaparoscopy (baseline disease assessment) was performed. The type, surface area and volume of endometriotic lesions (typical, red, white, or suspicious) were recorded and the revised ASRM score and stage were calculated. Baboons were then randomized into 4 groups and treated for a total duration of 60 days. They received banana (placebo, n=5), 20 mg/kg JNK inhibitor orally (n=5), JNK Inhibitor + 10mg Medroxy progesterone acetate (MPA) orally (n=5), Cetrorelix acetate (GnRH antagonist) 3 mg every three days subcutaneously (n=5). A posttreatment videolaparoscopy was performed to compare the extent of endometriosis in the 4 groups. Data were analysed with nonparametric statistics. RESULTS: In contrast with the placebo group, baboons treated with JNK Inhibitor, with JNK Inhibitor + MPA, or with Cetrorelix all showed a statistically significant reduction of the total surface area (p=<0.05) and volume (P=<0.05) of endometriotic lesions after treatment when compared to their pelvic status before treatment. These data were confirmed when red lesions were analyzed separately. Remodelling of red active lesions into white lesions was observed more frequently (p=<0.05) in baboons treated with the combination of JNK inhibitor and MPA than in baboons treated with placebo. CONCLUSIONS: JNK inhibitors effectively diminish the burden of endometriosis disease in a baboon model with induced endometriosis. The addition of MPA to JNK inhibitors may favor the healing process of endometriotic lesions.

Connexin expression pattern in the endometrium of baboons is influenced by hormonal changes and the presence of endometriotic lesions

Experimentally induced endometriosis in baboons serves as an elegant model to discriminate between endometrial genes which are primarily associated with normal endometrial function and those that are changed by the presence of endometriotic lesions. Since connexin genes are characteristic of the hormonally regulated differentiation of the endometrium, we have examined connexin expression in baboon endometrium to delineate if they are altered in response to the presence of endometriotic lesions. Connexin expression in the endometrium of cycling baboons is similar to that of the human endometrium with Connexin(Cx)43 being primarily seen in the stromal compartment and Cx26 and Cx32 being present predominantly in the epithelium. Although Cx32 is up-regulated during the secretory phase, Cx26 and Cx43 are down-regulated. In the baboon model of induced endometriosis a change in connexin pattern was evident in the presence of endometriotic lesions. In the secretory phase, Cx26 and Cx32 are no longer present in the epithelium but Cx26 is now observed primarily in the stromal cells. Infusion of chorionic gonadotrophin in a manner that mimics blastocyst transit in utero failed to rescue the aberrant stromal expression of Cx26 that is associated with the presence of endometriotic lesions suggesting an impairment of the implantation process. The altered connexin pattern coupled with a loss of the channel protein in the epithelium and a gain of Cx26 in the stromal compartment suggests that the presence of lesions changes the uterine environment and thereby the differentiation programme. This aberrant expression of connexins may be an additional factor that contributes to endometriosis-associated infertility.

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

To determine the effects of a thiazolidinedione (TZD) agonist of peroxisome proliferator-activated receptor (PPAR)-gamma, rosiglitazone, in a baboon model of established endometriosis. Prospective, randomized, placebo-controlled study. Experimental surgery laboratory at the Institute of Primate Research in Nairobi, Kenya. 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. 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. 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. 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. 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.

Treatment with anti-TNF monoclonal antibody (c5N) reduces the extent of induced endometriosis in the baboon

Inflammatory cytokines, including interleukin (IL)-1, IL-6, IL-8 and tumour necrosis factor-alpha (TNF-alpha), are important in the pathogenesis of endometriosis. We assessed the efficacy of anti-TNF monoclonal antibody (mAb, c5N), known to prevent induced endometriosis in baboons, in reducing established endometriosis in baboons. This prospective, randomized, blinded, controlled study was conducted in baboons at the Institute of Primate Research (IPR), Nairobi, Kenya. Endometriosis was induced in 18 adult female baboons (Papio anubis) with regular menstrual cycles and a normal pelvis; the extent of endometriosis was documented by videolaparoscopy 25 days later. The baboons were then randomly assigned to receive a single infusion of either placebo (n=7, 5 ml/kg) or c5N (n=11, 5 mg/kg). Follow-up laparoscopy was performed 25 days later to document any differences in the number, surface area and estimated volume of lesions between the two groups and between the first and the second laparoscopies in each group. Representative biopsies of at least one endometriotic lesion per baboon were obtained at the final laparoscopy. Significant reductions in total surface area, estimated total volume of endometriotic lesions and both number and surface area of red lesions were observed after treatment with c5N, but not after placebo treatment, when compared to the initial laparoscopy. Conversely, a significant increase in the number of typical and red lesions was observed after placebo treatment when compared to the initial laparoscopy. Neither c5N nor placebo treatment affected the menstrual cycle. In baboons with induced endometriosis, anti-TNF-mAb (c5N) treatment significantly reduced the extent of endometriosis, mainly due to reducing both the number and surface area of red lesions. These findings suggest that anti-TNF-mAb therapy may have therapeutic potential for active peritoneal endometriosis.

Induced Endometriosis in the Baboon (Papio anubis) Increases the Expression of the Proangiogenic Factor CYR61 (CCN1) in Eutopic and Ectopic Endometria1

The expression of human CYR61 (cysteine-rich, angiogenic inducer, 61; CCN1) mRNA has been previously shown to be deregulated in the endometrium of women with endometriosis. We have chosen the baboon model (Papio anubis) of induced endometriosis to clarify whether CYR61 mRNA upregulation is predisposed to an inappropriately differentiated endometrium or is deregulated as a response to the presence of ectopic lesions. In the baboon, endometrial CYR61 mRNA expression underwent moderate cyclical variation, with a significant 7.3-fold increase detected at Day 2 postmenses when compared to endometrium from the proliferative and secretory phases. The CYR61 transcript was extensively upregulated in the eutopic endometrium from all baboons with induced endometriosis, as early as 1 mo postinoculation of menstrual tissue into the peritoneal cavity. CYR61 mRNA expression then decreased throughout progression of the disease, but remained higher compared to control tissues. Ectopic endometriotic lesions showed a further increase in CYR61 mRNA, with highest expression found in red lesions. Moreover, the expression levels of CYR61 transcripts correlated significantly with those of VEGF. Immunohistochemistry revealed the presence of CYR61 protein in glandular and luminal epithelial cells as well as in blood vessels of eutopic and ectopic endometrium. As in humans, increased levels of CYR61 mRNA correlated with the development of endometriosis in baboons. The increase of CYR61 mRNA in eutopic endometrium of baboons following peritoneal inoculation with menstrual endometrium provides evidence for a feedback mechanism from resulting lesions to induce a shift in gene expression patterns in the eutopic endometrium.

Recombinant Human TNFRSF1A (r-hTBP1) Inhibits the Development of Endometriosis in Baboons: A Prospective, Randomized, Placebo- and Drug-Controlled Study1

Endometriosis is associated with chronic inflammation, including an increased macrophage activity with increased secretion of cytokines, such as tumor necrosis factor (TNF) or TNF superfamily member 2, previously known as TNFalpha. In the present study, we tested the hypothesis that recombinant human TNFRSF1A (r-hTBP1) can inhibit the development of endometriotic lesions in the baboon, an established model for the study of endometriosis. Endometriosis was induced using intrapelvic injection of menstrual endometrium in 20 baboons with a normal pelvis. In the first part of the study, 14 baboons were randomly assigned to subcutaneous treatment with r-hTBP1, placebo, or GnRH antagonist (positive control). In the second part of the study, menstrual endometrium from 6 baboons was randomly incubated with either PBS or r-hTBP1 before intrapelvic seeding. Video laparoscopy was performed 25 days later to document the number, surface area, and estimated volume of endometriotic lesions and adhesions; to calculate the revised American Fertility Society (rAFS) score and stage; and to confirm the histological presence of endometriosis. In the first part, baboons treated with r-hTBP1 or with Antide (Bachem) had a lower endometriosis rAFS score, a lower surface area and estimated volume of peritoneal endometriotic lesions, and a lower histological confirmation rate compared with controls. Because of less adnexal and cul-de-sac adhesions, the number of baboons with endometriosis of stage II, III, or IV was lower among baboons treated with r-hTBP1 or Antide than among controls. In the second part, the surface area of endometriotic lesions was lower, and less severe endometriosis was observed in r-hTBP1-treated baboons. No hypoestrogenic effects were observed in baboons treated with r-hTBP1. In conclusion, r-hTBP1 can effectively inhibit the development of endometriosis without hypoestrogenic effects in baboons.

Treatment with anti-TNF antibody c5N reduces the extent of induced endometriosis in the baboon

Inflammatory cytokines, including IL-1, IL-6, IL-8 and TNF-α, are accepted to be important in the pathogenesis of endometriosis. Previous studies (D’Hooghe et al, 2001) have shown that TNFα-binding protein can prevent the development of induced endometriosis in baboons. In this study, we tested the hypothesis that anti-TNF monoclonal antibody treatment can treat established endometriosis in baboons.

Efficacy of anti-tumor necrosis factor therapy in the treatment of spontaneous endometriosis in baboons

Objective To determine the efficacy of anti-tumor necrosis factor therapy (etanercept) for treating endometriosis in baboons. Design A randomized, placebo-controlled, blinded study using the baboon endometriosis model. Setting Southwest National Primate Research Center. Animal(s) Twelve female baboons with spontaneous peritoneal endometriosis. Intervention(s) Etanercept (n = 8) or sterile water (n = 4) was administered subcutaneously three times per week. Main outcome measure(s) After 8 weeks, the number, color, and surface area of peritoneal lesions was evaluated. Revised American Society for Reproductive Medicine staging was used. Result(s) A statistically significant decrease in red lesion surface area in the treatment group was observed. A trend toward a decrease in the absolute number of red lesions was noted in the treatment group. White and black lesion number and total surface area slightly increased in both groups but failed to achieve statistical significance. Endometriosis was diagnosed in 60% of captive-born baboons with primary infertility. Conclusion(s) These results indicate that etanercept effectively reduces the amount of spontaneously occurring active endometriosis in the baboon.

Uterine receptivity and implantation: The regulation and action of insulin-like growth factor binding protein-1 (IGFBP-1), HOXA10 and forkhead transcription factor-1 (FOXO-1) in the baboon endometrium

In primates, the phase of the menstrual cycle when the uterus becomes receptive is initially dependent on estrogen and progesterone. Further morphological and biochemical changes are induced as a result of biochemical signals between the embryo and the maternal endometrium. Blastocyst implantation in the baboon usually occurs between 8 and 10 days post ovulation and is similar to that described for the rhesus macaque. In the baboon, when chorionic gonadotropin is infused in a manner that mimics blastocyst transit, this has physiological effects on the three major cell types in the uterine endometrium. The luminal epithelium undergoes endoreplication and distinct epithelial plaques are evident. The glandular epithelium responds by inducing transcriptional and post-translational modifications in the major secretory product, glycodelin. The stromal fibroblasts initiate their differentiation process into a decidual phenotype and are characterized by the expression of actin filaments. Decidualization, is the major change that occurs in the primate endometrium after conception. During this process the fibroblast-like stromal cells change morphologically into polygonal cells and express specific decidual proteins. Studies in the baboon demonstrated that insulin-like growth factor binding protein-1 (IGFBP-1) gene expression is a conceptus-mediated response. Subsequent studies in vitro established that IGFBP-1 is transcriptionally regulated by FOXO1 and HOXA10 which together upregulate the IGFBP-1 promoter activity. A baboon endometriosis model was utilized to determine if the changes observed during uterine receptivity in normally cycling animals were compromised. The data suggests that in animals with disease, markers of uterine receptivity are not appropriately expressed in the eutopic endometrium. It is possible that these differences influence the fertility of the animals with disease and the baboon could be used as a primate model to study the causes of infertility as a result of endometriosis.