Immunology of endometriosis

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.

Identification of local angiogenic and inflammatory markers in the menstrual blood of women with endometriosis

The aim of this study was to evaluate the presence of myeloperoxidase (MPO), N-acetyl-β-D-glucosaminidase (NAG), tumor necrosis factor alpha (TNF-α) and vascular endothelial growth factor (VEGF) in peripheral and menstrual blood in women with (n=10) and without (n=7) endometriosis. NAG and MPO activities were evaluated by enzymatic methods, whereas TNF-α and VEGF by immunoassay. No significant differences were found for these markers, neither in menstrual nor in peripheral blood between groups. Menstrual blood NAG (P=0.039) and MPO (P=0.0117) activities in the endometriosis group were significantly higher than in peripheral blood. NAG and MPO presented positive linear correlation in peripheral (P=0.07; r=0.641) and menstrual blood (P=0.01; r=0.603). These findings point to the existence of an increased local inflammatory activity in women with endometriosis.

The association between endometriosis and chronic endometritis

Objective

To evaluate the association between endometriosis and chronic endometritis.

Methods

Endometrial specimens were obtained from 71 patients, 34 with endometriosis (endometriosis group) and 37 without endometriosis (non-endometriosis group), who underwent hysterectomy, and the specimens were immunostained for the plasmacyte marker CD138. The rate of chronic endometritis was compared between the endometriosis group and the non-endometriosis group. Furthermore, the 71 patients were also divided into two groups, 28 with chronic endometritis (chronic endometritis group) and 43 without chronic endometritis (non-chronic endometritis group). Logistic regression analysis was performed with variables including age, body mass index (BMI), gravidity and parity, and diagnoses of leiomyoma, adenomyosis, and endometriosis on pathology to examine the independent effect of each variable on chronic endometritis. Patients suffering from cervical invasive carcinoma, endometrial carcinoma, and endometrial polyps or treated with gonadotropin-releasing hormone agonists, progestins, or oral contraceptives before surgery were excluded.

Results

Chronic endometritis was identified in 52.94% of the endometriosis group and 27.02% of the non-endometriosis group (p<0.05). Logistic regression analysis revealed that endometriosis was associated with chronic endometritis.

Conclusions

This result suggests a strong association between endometriosis and chronic endometritis.

Effect of the bone marrow derived-mononuclear stem cells transplantation in the growth, VEGF-R and TNF-alpha expression of endometrial implants in Wistar rats

OBJECTIVE

To study the effect of bone marrow derived-mononuclear stem cells transplantation in the growth, VEGF-R and TNF-alpha expression of surgically induced endometriosis in an experimental model.

STUDY DESIGN

This is an experimental study conducted in the Center for Health and Biological Sciences at the Pontifical Catholic University of Parana, Brazil. Endometriotic implants were surgically induced in 120 female Wistar rats. The animals with viable endometrial implant (larger than 25 mm(2)) were randomically divided into 3 groups to receive an intraperitoneal injection of 0.2 cc of saline solution (C group; n=30), a subcutaneous injection of 1mg/kg of leuprolide (L group; n=34), or an intraperitoneal injection of 5×10(6) bone marrow derived-mononuclear stem cells (SC group; n=36). They were sacrificed after 21 days to assess the implants' size and the tissue expression of vascular endothelial growth factor receptor (VEGF-R) and tumor necrosis factor-alpha (TNF-alpha).

RESULTS

Treatment with leuprolide decreased the surface area of the endometriotic implant compared to the SC group and the C group. The absolute reduction in the surface area of the implant was 16.5mm, 0mm, and 0mm (p=0.007), respectively, and the percent reduction was 40.2%, 0%, and 0% (p=0.001). VEGF-R expression in the endometriotic implant decreased after treatment in the L and SC groups compared to the C group (409.6 μm(2) vs. 465 μm(2) vs. 920.9 μm(2), respectively; p=0.021). TNF-alpha expression also reduced in the L and SC groups compared to the C group (585.7 μm(2) vs. 549.3 μm(2) vs. 2402.1 μm(2), respectively; p<0.001).

CONCLUSION

Bone marrow derived-mononuclear stem cells transplantation decreased the expression of VEGF-R and TNF-alpha in the endometriotic implant but did not reduce the surface area of the lesion.

Endometrial and peritoneal expression of aromatase, cytokines, and adhesion factors in women with endometriosis

OBJECTIVE

To examine messenger (m) RNA expression of aromatase, cytokines, and adhesion factors in women with and without endometriosis.

DESIGN

Patients with endometriosis were compared with control patients.

SETTING

University Hospital Gasthuisberg, Leuven, Belgium.

PATIENT(S)

A total of 35 patients who had laparoscopic surgery during the luteal phase (n = 20) or the menstrual phase (n = 15) were selected for this study based on cycle phase and presence/absence of endometriosis.

INTERVENTION(S)

Tissues of endometrium and macroscopically normal peritoneum were collected during hysteroscopy and laparoscopic surgery, respectively, from 24 women with revised American Society for Reproductive Medicine stage (rASRM) stages I-II (n = 12) and III-IV (n = 12) endometriosis and 11 control patients with normal pelvic. Tissue samples were selected from a tissue bank, based on the phase of the cycle (menstrual or luteal) and the presence/absence of endometriosis.

MAIN OUTCOME MEASURE(S)

The mRNA levels of aromatase, vimentin, vascular cell adhesion molecule 1 (VCAM-1), alpha(V) and beta(3) integrins, interleukin (IL)-1 beta, regulated on activation normal T-cell expressed and secreted (RANTES), and monocyte chemotactic protein 1 (MCP-1) were evaluated using real-time reverse transcriptase polymerase chain reaction.

RESULT(S)

During menstrual phase, increased endometrial mRNA levels of alpha(V) integrin, combined alpha(V)beta(3) integrins, and increased peritoneal IL-1 beta mRNA levels--but decreased peritoneal MCP-1 mRNA levels--were observed in women with endometriosis compared with control subjects. During luteal phase, endometrial mRNA levels of IL-1 beta and RANTES were increased in women with endometriosis compared with control subjects. Endometrial aromatase mRNA expression was higher in women with endometriosis than in control subjects in combined phases. Women with endometriosis had increased peritoneal mRNA expression of RANTES and VCAM-1 during menstrual compared with luteal phase.

CONCLUSION(S)

Aberrant mRNA expression of aromatase, cytokines, and adhesion factors in endometrium and peritoneum suggests that both tissues are involved in the pathogenesis of endometriosis.

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.

Peroxisome proliferator-activated receptor-gamma induces regression of endometrial explants in a rat model of endometriosis

OBJECTIVE

To determine the effects of a thiazolidinedione, ciglitazone, in a rat model of endometriosis.

DESIGN

Prospective, randomized, placebo-controlled study.

SETTING

Experimental surgery laboratory in a university department.

ANIMAL(S)

Twenty female Sprague-Dawley rats given endometriotic lesions by transplanting autologous uterine tissue to ectopic sites on the peritoneum.

INTERVENTION(S)

Four weeks after surgery, 20 rats were randomly divided into two groups and treated with IP injections of vehicle every other day (control; n = 10) or ciglitazone (1 mg per rat; n = 10) and euthanized 4 weeks from the start of treatment.

MAIN OUTCOME MEASURE(S)

At the end of treatment, laparotomy was performed to photograph each explant and then they were measured and weighed. Histologic analysis was performed on the uterine allograft, ovary, and eutopic uterine tissue.

RESULT(S)

By histologic assessment, both groups maintained folliculogenesis and normal eutopic endometrial architecture. Treatment with ciglitazone significantly decreased the size of ectopic uterine tissues and the mean explant wet weight. The ciglitazone-treated group showed marked epithelial regression compared with the control group.

CONCLUSION(S)

We conclude that a PPAR-gamma ligand, ciglitazone, reduced the size of experimental endometriosis in the rat model of endometriosis. This animal model suggests that a thiazolidinedione drug may be helpful in women with endometriosis.