Tayfun Ide

Comparison of aromatase inhibitor (letrozole) and immunomodulators (infliximab and etanercept) on the regression of endometriotic implants in a rat model.

OBJECTIVE Novel treatment strategies are needed in the treatment of endometriosis due to limited success rates with the currently available options. As inflammatory and immunological mechanisms have been shown to be involved in the mechanism of the disease, new modalities are likely to emerge. We investigated the effects of infliximab (INF), etanercept (ETA) and letrozole on the regression of experimental endometriosis. STUDY DESIGN In this experimental randomized trial, endometriosis was induced surgically in 44 adult female Sprague-Dawley rats. Establishment of implants was confirmed in 41 animals by a second operation on the 21st day. The rats were then randomly divided into four groups. Group I (n = 10) served as controls. Group II (n = 11) received letrozole (0.18 mg/kg, i.p.), group III (n = 10, i.p.) ETA (2.016 mg/kg, i.p.), and group IV (n = 10) INF (15.12 mg/kg, i.p.) for a second 21-day period. Endometriotic implant size along with peritoneal fluid VEGF level and immunoreactivity were determined before and after the treatment in each group. RESULTS Endometriotic implant size reduced in all treatment groups. The effect of letrozole and ETA on implant size was similar but was significantly better than INF. Level of VEGF in peritoneal fluid did not change in any treatment group but post-treatment VEGF immunoreactivity was found significantly lower in the letrozole treated group. CONCLUSIONS Letrozole and ETA caused a regression on the implant size in experimental endometriosis. The only group with decreased VEGF expression was letrozole.

The aromatase inhibitor letrozole reduces adhesion formation after intraperitoneal surgery in a rat uterine horn model

OBJECTIVE To investigate, in an experimental animal study, the effects of letrozole and tamoxifen in the reduction of adhesion formation following abdominopelvic surgery. STUDY DESIGN Thirty female Wistar albino rats were included and divided into three groups. One group received 500 μg/d tamoxifen and a second group received 1 mg/kg/d letrozole through an enteric tube. A third group did not receive any drugs and served as the control group. On the fifth day, a laparotomy was performed and the right uterine horn was injured by monopolar cautery. The left uterine horn was incised with a scalpel and sutured. The preventive therapy protocols were continued for 7 days after surgery. On the 14th day after first surgery the animals were sacrificed, and the intraperitoneal macroscopic adhesion formation and microscopic adhesion features were evaluated. The Kruskal-Wallis test was used to compare the scores of the macroscopic adhesion scores and histologic features among the three groups, followed by a post hoc Mann-Whitney test. The total histological score was analyzed with a one-way ANOVA, followed by post hoc Bonferroni correction tests. p values ≤0.05 were considered statistically significant. The level of significance was set at p≤0.016 for the post hoc tests. RESULTS The letrozole and tamoxifen groups had significantly lower adhesion scores for the right uterine horn than the control group (p=0.005 and p=0.013, respectively). For the left horn, however, only the letrozole group had a lower macroscopic adhesion score than the controls (p=0.011). The total histological score was significantly lower in the letrozole group than in the control group (p=0.014), but no differences were found between the tamoxifen group and the control group (p=0.954). Inflammation, fibroblastic activity, collagen formation and vascular proliferation were significantly lower in the letrozole group compared with the control group (p<0.05). The foreign body reactions were similar among the three groups (p>0.05). Tamoxifen administration did not result in any significant effects on the histological scores (p>0.05). CONCLUSION Letrozole resulted in a significant decrease in postoperative macroscopic adhesion formation and the total histological scores, but tamoxifen did not demonstrate a similar effect on the histological scores.

Immunosuppressive effects of multipotent mesenchymal stromal cells on graft-versus-host disease in rats following allogeneic bone marrow transplantation.

Objective: Graft-versus-host disease (GVHD) is a major obstacle to successful allogeneic bone marrow transplantation (allo-BMT). While multipotent mesenchymal stromal cells (MSCs) demonstrate alloresponse in vitro and in vivo, they also have clinical applications toward prevention or treatment of GVHD. The aim of this study was to investigate the ability of MSCs to prevent or treat GVHD in a rat BMT model. Materials and Methods: The GVHD model was established by transplantation of Sprague Dawley rats’ bone marrow and spleen cells into lethally irradiated (950 cGy) SDxWistar rat recipients. A total of 49 rats were randomly assigned to 4 study and 3 control groups administered different GVHD prophylactic regimens including MSCs. After transplantation, clinical GVHD scores and survival status were monitored. Results: All irradiated and untreated control mice with GVHD died. MSCs inhibited lethal GVHD as efficiently as the standard GVHD prophylactic regimen. The gross and histopathological findings of GVHD and the ratio of CD4/CD8 expression decreased. The subgroup given MSCs displayed higher in vivo proportions of CD25+ T cells and plasma interleukin-2 levels as compared to conventional GVHD treatment after allo-BMT. Conclusion: Our results suggest that clinical use of MSCs in both prophylaxis against and treatment of established GVHD is effective. This study supports the use of MSCs in the prophylaxis and treatment of GVHD after allo-BMT; however, large scale studies are needed. Conflict of interest:None declared.