Alison J. Hey-Cunningham

The role of Foxp3+ regulatory T-cells in endometriosis: a potential controlling mechanism for a complex, chronic immunological condition

BACKGROUND Endometriosis is an inflammatory condition, associated with highly dysregulated immune response at both uterine and peritoneal levels. Surprisingly, Foxp3+ regulatory T-cells, which control and suppress a range of immune responses, have not previously been investigated in endometriosis. METHODS AND RESULTS Immunohistochemical analysis of Foxp3+ cells in 127 eutopic endometrial samples and 59 ectopic peritoneal lesions revealed that these immune cell populations are highly disturbed in women suffering from endometriosis. We showed that Foxp3+ cells remained highly up-regulated during the secretory phase of the menstrual cycle, while at this time their expression is significantly down-regulated in women without endometriosis (P < 0.001). Foxp3+ cells were detected in the stroma of 18 of the 59 peritoneal endometriotic lesions, but not in the surrounding or control peritoneal tissue. CONCLUSIONS We propose that in eutopic endometrium in women with endometriosis Foxp3+ cells decrease the ability of newly recruited immune cell populations to effectively recognize and target endometrial antigens shed during menstruation, allowing their survival and ability to implant in ectopic sites. At these ectopic sites, variable expression of Foxp3+ cells within some peritoneal endometriotic lesions is likely to be linked to the characteristics and stage of individual lesion development and be playing key roles in pathogenesis and progression of this unique condition.

Angiogenesis, lymphangiogenesis and neurogenesis in endometriosis.

Endometriosis is a common, benign gynecological disease affecting 10 - 15% of reproductively aged women. It is characterized by the presence of endometrial-like tissue at sites outside the uterus. The most widely accepted theory of endometriosis pathogenesis proposes that shed menstrual endometrium can reach the peritoneum, implant and grow as endometriotic lesions. Angiogenesis, lymphangiogenesis and neurogenesis are implicated in successful ectopic establishment and the generation of endometriosis-associated symptoms. This review considers these processes as they occur in the eutopic endometrium and ectopic endometriotic lesions of women with endometriosis. Their regulation is inter-connected and complex. Dysregulation in endometriosis occurs on a background of accumulating evidence that endometriosis is an endometrial disease with underlying genetic influences and cross talk with endometriotic lesions. Understanding the roles of angiogenesis, lymphangiogenesis and neurogenesis in endometriosis pathophysiology is essential for the development of novel therapeutic approaches.

Endometrial stromal cells and immune cell populations within lymph nodes in a nonhuman primate model of endometriosis.

Mounting evidence suggests that immunological responses may be altered in endometriosis. The baboon (Papio anubis) is generally considered the best model of endometriosis pathogenesis. The objective of the current study was to investigate for the first time immunological changes within uterine and peritoneal draining lymph nodes in a nonhuman primate baboon model of endometriosis. Paraffin-embedded femoral lymph nodes were obtained from 22 normally cycling female baboons (induced endometriosis n = 11; control n = 11). Immunohistochemical staining was performed with antibodies for endometrial stromal cells, T cells, immature and mature dendritic cells, and B cells. Lymph nodes were evaluated using an automated cellular imaging system. Endometrial stromal cells were significantly increased in lymph nodes from animals with induced endometriosis, compared to control animals (P = .033). In animals with induced endometriosis, some lymph node immune cell populations including T cells, dendritic cells and B cells were increased, suggesting an efficient early response or peritoneal drainage.

Dysregulation of Vascular Endothelial Growth Factors and Their Neuropilin Receptors in the Eutopic Endometrium of Women With Endometriosis

Despite the importance of neuropilins (NRPs) in a number of processes that are altered in endometriosis, such as angiogenesis and neuronal guidance, these molecules have not been previously studied in the disease. Similarly, potent lymphangiogenic factors, vascular endothelial growth factor C (VEGF-C) and VEGF-D, have not been comprehensively investigated in endometriosis. The objective of this study was to examine their expression in women with and without endometriosis. NRPs and VEGFs were quantified in 79 histologically normal uterine tissue samples (37 control and 42 endometriosis, all menstrual cycle phases) using immunohistochemistry and automated cellular imaging analysis. NRP-1 was significantly reduced in women with endometriosis (P = .004). The normal significant menstrual cyclical variations in endometrial NRP-1, NRP-2, and VEGF-C were absent in endometriosis, and VEGF-D was dysregulated. Dysregulated expression of growth factors and receptors, such as NRPs and VEGFs, likely contribute to altered angiogenesis, lymphangiogenesis, neurogenesis and immune function in endometriosis and may reflect altered hormone signals.

The Role of the Lymphatic System in Endometriosis: A Comprehensive Review of the Literature

ABSTRACT Endometriosis is a benign gynecological disorder characterized by the presence of tissue resembling the endometrium in locations outside the uterus. The pathogenesis of endometriosis is still unknown; however, it is believed that the lymphatic system plays major roles in the development and progression of the disease. The lymphatic dissemination theory has been proposed to explain the presence of endometrial and/or endometriotic tissue in lymphatic vessels, lymph nodes, and rare sites, as well as high reoccurrence rates following treatment. Despite the importance of the lymphatic system in many aspects of endometriosis, there has been no previous thorough scientific update on its role in the disease. A review of scientific literature on the lymphatic system, lymphangiogenesis, and immunological changes associated with endometriosis was conducted. Lymphangiogenic potential is disturbed and lymphatic vessel density increased in the eutopic endometrium of women with endometriosis, likely promoting the entry of endometrial tissues into the lymphatic circulation. Endometriotic lesions and endometrial-like cells are present in uterine-draining nodes and various other pelvic lymph nodes. Immune responses are impaired in uterine-draining nodes, likely favoring the survival of endometrial cells and lesion establishment. In addition, lymphangiogenesis in endometriotic lesions may contribute to lesion growth and persistence, and promote the spread of endometrial cells to draining lymph nodes. The evidence reviewed in this paper supports the theory of lymphatic dissemination of endometriosis and highlights the roles of the lymphatic system in the pathogenesis and persistence of endometriosis. Understanding these roles is crucial for establishment of novel therapeutic approaches.

Cellular immune environment in endometrial polyps

STUDY OBJECTIVE To investigate the immune environment of endometrial polyps (EPs). DESIGN Prospective case-control study. SETTING Teaching hospital and university research laboratory. PATIENT(S) Reproductive-age women undergoing hysteroscopy dilation and curettage for benign indications. Samples were collected from women with (n = 23) and without (n = 40) EPs. INTERVENTION(S) Endometrial samples were immunohistochemically stained with antibodies against mast cells (MCs) and regulatory T cells (Tregs). MAIN OUTCOME MEASURE(S) Tryptase+, chymase+, and c-Kit+ MCs and Foxp3+ Tregs were quantified in EPs and polyp-adjacent, polyp-distant, and control endometrium. RESULT(S) Densities of all MC types were highly significantly increased in EPs compared with adjacent, distant, and control endometrium. Chymase+ and c-Kit+ MCs were increased in density in adjacent compared with control endometrium. c-Kit+ MCs were also increased in distant compared with control endometrium. Foxp3+ Treg density was increased in EPs compared with distant and control endometrium and decreased in distant compared with control endometrium. CONCLUSION(S) This study provides novel insights into localized disturbances in the cellular immune environment within EPs consistent with EPs being inflammatory lesions associated with MC overactivity. Tregs are likely to be recruited to EPs in an attempt to suppress the inflammatory process due to the greatly increased presence of MCs. These immunologic disturbances are likely to be involved in the causation of abnormal bleeding and infertility in premenopausal women with EPs, and their role in the pathophysiology requires further research.

A Novel Pilot Study of Endometrial Stromal Cells and Immune Cell Populations in Sentinel Uterine-Draining Lymph Nodes During the Menstrual Cycle and in Endometriosis:

Recent studies suggest that changes in certain uterine immune cell populations in endometrium of women with endometriosis are likely to precede changes at ectopic sites. This preliminary study is a first look into the function of uterine-draining lymph nodes (LNs) during the menstrual cycle and in the presence of endometriosis. Paraffin-embedded obturator LNs were obtained from women with (n = 7, mean age 44.3) and without (n = 9, mean age 38.4) endometriosis, who had undergone hysterectomy for cervical or ovarian cancer and in whom LN involvement was not detected. Immunohistochemical staining for endometrial stromal cells and a range of immune cell populations was performed. The CD10+ endometrial stromal cells were detected in uterine-draining LNs throughout the menstrual cycle with numbers peaking during menstruation. The inflammatory process of menstruation was also associated with increased numbers of CD3+, CD4+, Foxp3+, DC-Sign+, CD68+, CD20+, CD79+, and plasma cells. In endometriosis, CD10+ endometrial stromal cells were further increased in numbers, but CD3+, CD4+, DC-Lamp+, FoxP3+, and plasma cells were reduced. This study indicates that efficient immunological responses may be required to contain shed endometrial fragments within the draining uterine LNs thus preventing their further dissemination with establishment of ectopic lesions at distant sites.

Microanatomy and function of the eutopic endometrium in women with endometriosis

Endometriosis is a disease that still presents many puzzles to clinicians and basic research scientists. Until recently, it has been regarded as a condition that arises when normal endometrium adheres to the peritoneal surface and then grows into an ‘inflammatory’ lesion, which adversely influences local reproductive tract function and causes pain. It is now becoming clear that the endometrium within the uterus in these women differs significantly in function from ‘normal’, and that these anomalies probably precede the development of classical ectopic endometriotic lesions. However, the etiology and mechanisms by which endometriosis arises are still far from certain. This review attempts to address the extensive, but fragmented, evidence that demonstrates widespread molecular disturbances in endometrial function and microstructure underlying this complex condition. The review also addresses some of the novel concepts that are being raised by these exciting new discoveries.

Uterine lymphatic and blood micro-vessels in women with endometriosis through the menstrual cycle

PurposeEndometriosis is a common disease, associated with persistent and severe symptoms including infertility and pain, however, pathogenesis remains poorly understood. It has been hypothesized th...

High-resolution imaging of the large non-human primate brain using microPET: a feasibility study

The neuroanatomy and physiology of the baboon brain closely resembles that of the human brain and is well suited for evaluating promising new radioligands in non-human primates by PET and SPECT prior to their use in humans. These studies are commonly performed on clinical scanners with 5 mm spatial resolution at best, resulting in sub-optimal images for quantitative analysis. This study assessed the feasibility of using a microPET animal scanner to image the brains of large non-human primates, i.e. papio hamadryas (baboon) at high resolution. Factors affecting image accuracy, including scatter, attenuation and spatial resolution, were measured under conditions approximating a baboon brain and using different reconstruction strategies. Scatter fraction measured 32% at the centre of a 10 cm diameter phantom. Scatter correction increased image contrast by up to 21% but reduced the signal-to-noise ratio. Volume resolution was superior and more uniform using maximum a posteriori (MAP) reconstructed images (3.2-3.6 mm(3) FWHM from centre to 4 cm offset) compared to both 3D ordered subsets expectation maximization (OSEM) (5.6-8.3 mm(3)) and 3D reprojection (3DRP) (5.9-9.1 mm(3)). A pilot (18)F-2-fluoro-2-deoxy-d-glucose ([(18)F]FDG) scan was performed on a healthy female adult baboon. The pilot study demonstrated the ability to adequately resolve cortical and sub-cortical grey matter structures in the baboon brain and improved contrast when images were corrected for attenuation and scatter and reconstructed by MAP. We conclude that high resolution imaging of the baboon brain with microPET is feasible with appropriate choices of reconstruction strategy and corrections for degrading physical effects. Further work to develop suitable correction algorithms for high-resolution large primate imaging is warranted.