Thalidomide affects experimental endometriosis: A randomized controlled study in the rat

Comparing The Effects of Glycyrrhiza glabra Root Extract, A Cyclooxygenase-2 Inhibitor (Celecoxib) and A Gonadotropin-Releasing Hormone Analog (Diphereline) in A Rat Model of Endometriosis

Background

The purpose of this study was to compare the effects of Glycyrrhiza glabra (Licorice), a cyclooxyge- nase-2 inhibitor (Celecoxib) and a gonadotropin-releasing hormone analog (Diphereline®), with a control group on endometrial implants in rats.

Materials and Methods

In this experimental study, endometriosis was induced in rats by auto transplantation and after confirmation, the rats were divided into 4 groups that were treated for 6 weeks with normal saline (0.5 ml/day, orally), licorice extract (3000 mg/kg/day, orally), celecoxib (50 mg/kg, twice a day, orally) or diphereline (3 mg/kg, intramuscularly). At the end of treatments, the mean area, volume, histopathology and hemosiderin-laden macrophage (HLM) counts of the endometrial implants were evaluated and compared among the four groups.

Results

The mean area, volume and HLM counts of the implants in the licorice group were significantly lower than those of the control group (P<0.001). The histopathologic grades of endometrial implants were significantly decreased by licorice compared to the control group (P<0.001). There was no significant change in the mentioned parameters in rats treated with celecoxib compared to the control group. Diphereline was the most potent agent for suppressing the growth of endometrial implants in terms of all of the above-mentioned parameters.

Conclusion

Licorice decreased the growth and histopathologic grades of auto-transplanted endometrial implants. However, while celcoxib had no significant effect, diphereline showed the highest potency for decreasing the endome- trial growth. Licorice may have the potential to be used as an alternative medication for the treatment of endometriosis.

Anti-Angiogenic Alternative and Complementary Medicines for the Treatment of Endometriosis: A Review of Potential Molecular Mechanisms

Endometriosis is caused by the growth or infiltration of endometrial tissues outside of the endometrium and myometrium. Symptoms include pain and infertility. Surgery and hormonal therapy are widely used in Western medicine for the treatment of endometriosis; however, the side effects associated with this practice include disease recurrence and menopause, which can severely influence quality of life. Angiogenesis is the main biological mechanism underlying the development of endometriosis. Numerous natural products and Chinese medicines with potent anti-angiogenic effects have been investigated, and the molecular basis underlying their therapeutic effects in endometriosis has been explored. This review aims to describe natural products and compounds that suppress angiogenesis associated with endometriosis and to assess their diverse molecular mechanisms of action. Furthermore, this review provides a source of information relating to alternative and complementary therapeutic products that mediate anti-angiogenesis. An extensive review of the literature and electronic databases, such as the China National Knowledge Infrastructure, PubMed, and Embase, was conducted using the keywords 'endometriosis,' 'traditional Chinese medicine,' 'Chinese herbal medicine,' 'natural compounds,' and 'anti-angiogenic' therapy. Anti-angiogenic therapy is an emerging strategy for the treatment of endometriosis. Natural anti-angiogenic products and Chinese medicines provide several beneficial clinical effects, including pain relief. In this review, we summarize clinical trials and experimental studies of endometriosis using natural products and Chinese medicines. In particular, we focus on anti-angiogenic products and alternative and complementary medicines for the treatment of endometriosis and additionally examine their therapeutic efficacy and mechanisms of action. Anti-angiogenic natural products and/or compounds provide a new approach for the treatment of endometriosis. Future work will require randomized trials with larger numbers of subjects, as well as long-term follow-up to confirm the findings described here.

Kinase signalling pathways in endometriosis: potential targets for non-hormonal therapeutics

BACKGROUND

Endometriosis, the growth of endometrial tissue outside the uterine cavity, is associated with chronic pelvic pain, subfertility and an increased risk of ovarian cancer. Current treatments include the surgical removal of the lesions or the induction of a hypoestrogenic state. However, a reappearance of the lesion after surgery is common and a hypoestrogenic state is less than optimal for women of reproductive age. Additional approaches are required. Endometriosis lesions exist in a unique microenvironment characterized by increased concentrations of hormones, inflammation, oxidative stress and iron. This environment influences cell survival through the binding of membrane receptors and a subsequent cascading activation of intracellular kinases that stimulate a cellular response. Many of these kinase signalling pathways are constitutively activated in endometriosis. These pathways are being investigated as therapeutic targets in other diseases and thus may also represent a target for endometriosis treatment.

METHODS

To identify relevant English language studies published up to 2015 on kinase signalling pathways in endometriosis, we searched the Pubmed database using the following search terms in various combinations; 'endometriosis', 'inflammation', 'oxidative stress', 'iron', 'kinase', 'NF kappa', 'mTOR', 'MAPK' 'p38', 'JNK', 'ERK' 'estrogen' and progesterone'. Further citing references were identified using the Scopus database and finally current clinical trials were searched on the clinicaltrials.gov trial registry.

RESULTS

The current literature on intracellular kinases activated by the endometriotic environment can be summarized into three main pathways that could be targeted for treatments: the canonical IKKβ/NFκB pathway, the MAPK pathways (ERK1/2, p38 and JNK) and the PI3K/AKT/mTOR pathway. A number of pharmaceutical compounds that target these pathways have been successfully trialled in in vitro and animal models of endometriosis, although they have not yet proceeded to clinical trials. The current generation of kinase inhibitors carry a potential for adverse side effects.

CONCLUSIONS

Kinase signalling pathways represent viable targets for endometriosis treatment. At present, however, further improvements in clinical efficacy and the profile of adverse effects are required before these compounds can be useful for long-term endometriosis treatment. A better understanding of the molecular activity of these kinases, including the specific extracellular compounds that lead to their activation in endometriotic cells specifically should facilitate their improvement and could potentially lead to new, non-hormonal treatments of endometriosis.

The effects of thalidomide in a rat model of surgically-induced endometriosis

OBJECTIVE

The aim of the study was to analyze the anti-angiogenic role of thalidomide and to assess whether thalidomide had any influence on a rat model of surgically-induced endometriosis.

MATERIALS AND METHODS

Endometriosis was induced through surgical induction and homologous transplantation in 16 rats. The rats were randomly separated into two groups as thalidomide (n=8) and control (n=8) groups. Using oral gavage, 100 mg/kg thalidomide 0.5 ml was administered to the first group and saline 0.5 ml to the control group. Histopathologic findings and volume analysis of implants were evaluated after 4 weeks. Vascular endothelial growth factor-A (VEGF-A) and oxidative markers were run from the fluid through peritoneal lavage.

RESULTS

The average implant volume decreased significantly in the thalidomide administrated group after treatment (53.3 and 22.9 mm3 respectively, p=0.012). Significant differences observed in the histopathologic scores of the thalidomide group (3 and 1 respectively, p=0.012) were not observed in the control group. Significant decreases were observed in the levels of VEGF-A and myeloperoxidase (MPO) from oxidative markers (p=0.004, p=0.037, respectively).

CONCLUSION

Thalidomide provides volumetric and histopathologic recovery in implants particularly because the VEGF inhibition and anti-angiogenic effect, which suggests that it could be effective in the treatment of endometriosis.