Adult Stem Cells in the Pathogenesis and Treatment of Endometriosis

The Emerging Role of Menstrual-Blood-Derived Stem Cells in Endometriosis

The human endometrium has a complex cellular composition that is capable of promoting cyclic regeneration, where endometrial stem cells play a critical role. Menstrual blood-derived stem cells (MenSC) were first discovered in 2007 and described as exhibiting mesenchymal stem cell properties, setting them in the spotlight for endometriosis research. The stem cell theory for endometriosis pathogenesis, supported by the consensual mechanism of retrograde menstruation, highlights the recognized importance that MenSC have gained by potentially being directly related to the genesis, development and maintenance of ectopic endometriotic lesions. Meanwhile, the differences observed between MenSC in patients with endometriosis and in healthy women underlines the applicability of these cells as a putative biomarker for the early diagnosis of endometriosis, as well as for the development of targeted therapies. It is expected that in the near future MenSC will have the potential to change the way we manage this complex disease, once their long-term safety and effectiveness are assessed.

Modeling Endometrium Biology and Disease

The endometrium, lining the uterine lumen, is highly essential for human reproduction. Its exceptional remodeling plasticity, including the transformation process to welcome and nest the embryo, is not well understood. Lack of representative and reliable study models allowing the molecular and cellular mechanisms underlying endometrium development and biology to be deciphered is an important hurdle to progress in the field. Recently, powerful organoid models have been developed that not only recapitulate endometrial biology such as the menstrual cycle, but also faithfully reproduce diseases of the endometrium such as endometriosis. Moreover, single-cell profiling endeavors of the endometrium in health and disease, and of derived organoids, start to provide deeper insight into cellular complexity and expression specificities, and in resulting tissue processes. This granular portrayal will not only help in understanding endometrium biology and disease, but also in pinning down the tissue's stem cells, at present not yet conclusively defined. Here, we provide a general overview of endometrium development and biology, and the efforts of modeling both the healthy tissue, as well as its key diseased form of endometriosis. The future of modeling and deciphering this key tissue, hidden inside the womb, looks bright.

Laparoscopic morphological aspects and tentative explanation of the aetiopathogenesis of isolated endometriosis of the sciatic nerve: a review based on 267 patients

Background

Endometriosis of the sciatic nerve (ESN) is considered a rare disease. How can endometriosis develop within the sciatic nerve; a structure which has nothing in common with the uterus either anatomically or functionally, and why it occurs in the absence of any retroperitoneal/parametric endometriosis, is unknown. A better understanding of the pathophysiology of this enigmatic disease may improve its diagnosis and therapy.

Materials and Methods

From a pool of 452 patients operated for ESN, only patients with “isolated” endometriosis of the sciatic nerve” confirmed at laparoscopy were included in this study. Patients with suspicion of ESN by extension from a parametric, ovarian or other intraperitoneal deeply infiltrating endometriosis were excluded from this study.

Main outcome measure

All information acquired during the preoperative patient’s medical history and clinical examination were collected and compared with the morphological aspects of the disease observed by the laparoscopic treatment. Patients were classified into three groups according to the time interval between the onset of sciatic pain and the time of surgery: less than 1 year (Group 1), between 1 and 3 years (Group 2), and more than 3 years (Group 3).

Results

Two hundred sixty-seven consecutive patients were included in this study. In Group 1 (n=67), 76% of the patients presented with cyclical sciatica, without sensory or motor disorders of the lower limbs. Laparoscopic exploration found in the great majority of these patients only the presence of an isolated endometrioma in the nerve itself, the size of which was proportional to the time elapsed since the onset of pain. In Group 2 (n=83), pain had become constant in 91% of the patients with neurological disorders of the lower limb (foot drop, Trendelenburg gait, atrophied muscles) in about 30% of patients. Laparoscopic examination revealed, in addition to intraneural cystic lesions, a retroperitoneal fibrosis in more than 80% of the patients. In the third group (N=117), more than 80% of the patients presented with neurological disorders of the lower limb, with, on laparoscopic examination, massive retroperitoneal fibrosis with endometriomas in the nerve and adjacent pelvic wall muscles in all patients and an infiltration of the obturator nerve in 41% of patients.

Conclusions

The different morphologic aspects of ESN do not correspond to different forms of the disease, but obviously to one single disease at different stages of its evolution. ENS starts first with the development of an endometrioma within the sciatic nerve, then develops in a second step a perineural fibrosis that expands into the whole retroperitoneal space and finally involves surrounding anatomical structures. The ESN is a very particular pathology because it induces a completely new aspect on the pathogenesis of endometriosis: all hypothesis of implanted endometrial cells following retrograde menstruation, angiogenic spread, lymphogenic spread or the metaplasia theory cannot explain the pathogenesis of this disease. ESN obviously does not develop from “genital metastatic cells”. A possible hypothesis for explanation the pathogenesis of ESN, could consist in the development of endometriosis of the nerve from progenitor stem cells present within the nerve, pluripotent cells which, for an as yet unknown reason (possibly in connection with iterative inflammations and micro-damages of the nerve itself), mutate and proliferate to form endometriosis.

The role of endometrial stem cells in the pathogenesis of endometriosis and their application to its early diagnosis†

Pelvic pain, infertility, and a high postoperative recurrence rate are associated with endometriosis and adversely affect the physical and mental health of patients. Moreover, these factors place a heavy burden on families and society. The identification of endometrial stem cells (EnSCs) in the eutopic endometrium, menstrual blood, and ectopic lesions of women with endometriosis not only provides new research objects in the context of endometriosis but also promotes and improves our understanding of its pathogenesis. Furthermore, based on previous studies, we reasonably suppose that dysfunctions of eutopic EnSCs play a critical role in the onset of endometriosis and directly cause abnormalities in the endometrium; subsequently, retrograde menstruation facilitates the delivery of abnormal endometrial tissues to the ovaries and pelvic cavity, where they ectopically implant, grow, and form ectopic lesions. Additionally, as a chronically progressive disease, there is a delay (3-11 years) from the first onset of symptoms to the diagnosis of endometriosis. Therefore, the development of a method for early diagnosis with high sensitivity and specificity is essential for endometriosis patients and has the potential to enable early treatment, prevent endometriosis progression, and relieve pain in patients. Thus, focusing on EnSCs will contribute to clarifying the potential pathogenesis of endometriosis and provide support for the application of EnSCs as therapeutic and early diagnostic targets in endometriosis treatment.

SUMMARY SENTENCE

Focusing on endometrial stem cells (EnSCs) will contribute to clarifying the potential pathogenesis of endometriosis and provide support for the application of EnSCs as therapeutic and early diagnostic targets in endometriosis treatment.

Biological characteristics of endometriotic mesenchymal stem cells isolated from ectopic lesions of patients with endometriosis

BACKGROUND

Research into the pathogenesis of endometriosis (EMs) would substantially promote its effective treatment and early diagnosis. However, the aetiology of EMs is poorly understood and controversial despite the progress in EMs research in the last several decades. Currently, accumulating evidence has shed light on the importance of endometrial stem cells (EnSCs) residing in the basal layer of endometrium in the establishment and progression of endometriotic lesions. Therefore, we aimed to identify the differences between EnSCs isolated from the ectopic lesions of EMs patients (EnSC-EM-EC) and EnSCs isolated from eutopic endometrium of control group (EnSC-Control). We further performed preliminary exploration of the potential signalling pathways involved in the above abnormalities.

METHODS

EnSC-EM-EC (n = 12) and EnSC-Control (n = 13) were successfully isolated. Then, the proliferative capacity, migratory capacity and angiogenic potential of EnSCs were evaluated by conventional MTT assay, flow cytometry, wound healing assay, transwell assay, tube formation assay and chick embryo chorioallantoic membrane assay respectively. The expression of 11 angiogenesis-associated biological factors and 11 cytokines secreted by EnSCs and 17 adhesion molecules expressed on EnSCs were determined by protein array assays respectively. Differentially expressed genes (DEGs) between EnSC-EM-EC and EnSC-Control were analysed by RNA-sequence.

RESULTS

EnSC-EM-EC exhibited unique biological characteristics, including prolonged mitosis, enhanced migratory capacity and enhanced angiogenic potential. Greater amounts of angiogenic factors (especially VEGF and PDGF) were secreted by EnSC-EM-EC than by EnSC-Control; however, the distinct profiles of cytokines secreted by EnSC-EM-EC and adhesion molecules expressed by EnSC-EM-EC require further investigation. A total of 523 DEGs between EnSC-EM-EC and EnSC-Control were identified and analysed using the KEGG and Gene Ontology databases.

CONCLUSIONS

Our results not only improve the understanding of EMs but also contribute to the development of EnSC-EM-EC as a tool for EMs drug discovery. These cells could be of great help in exploiting promising therapeutic targets and new biomarkers for EMs treatment and prognosis.

Endometriosis - a decade later - still an enigmatic disease. What is the new in the diagnosis and treatment?

Endometriosis is a common disease in women of reproduction age. It causes pain and difficulty in getting pregnant. However the exact causes of infertility associated with endometriosis still remain controversial. The treatment of endometriosis consists of medical treatment of pain as well as medical and surgical treatment of infertility caused by endometriosis and assisted reproduction techniques. Since the treatment of endometriosis is often connected with diminishing ovarian reserve, the techniques for ovarian tissue preservation and oocyte and embryo freezing are used to maintain the ability for childbearing.