Vasculogenesis: a new piece of the endometriosis puzzle

Potential Mechanisms of Guizhi Fuling Wan in Treating Endometriosis: An Analysis Based on TCMSP and DisGeNET Databases

ETHNOPHARMACOLOGICAL RELEVANCE

Guizhi Fuling Wan (GFW), is a traditional Chinese herbal formula that consists of Cinnamomi Ramulus (Guizhi), Poria Cocos(Schw.) Wolf. (Fuling), Persicae Semen (Taoren), Radix Paeoniae Rubra (Chishao), and Cortex Moutan (Mudanpi). This formula has been used in traditional Chinese medicine for more than 1800 years to treat disorders caused by stagnation of circulation and qi (air).

AIM OF THE STUDY

Based on pre-clinical and clinical studies, this review aimed to reveal the potential mechanisms of GFW in inhibiting endometriosis. The enhancement of therapeutic effects of western medications on endometriosis by GFW was also shown.

MATERIALS AND METHODS

A bibliographic assessment of publications on "Guizhi Fuling Wan" and "endometriosis" indexed in PubMed, Science Direct, and China National Knowledge Infrastructure (CNKI) was conducted. Five pre-clinical studies and 13 clinical studies were selected for this review. Moreover, the targeted molecules of each herb were first extracted from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) Database and Analysis Platform followed by obtaining the endometriosis-related genes from DisGeNET. Subsequently, pathway and gene ontology analyses using David Bioinformatics Resources explored the potential mechanisms of therapeutic effects of GFW in treating endometriosis.

RESULTS

Pre-clinical and clinical studies showed that GFW might inhibit the growth of endometriotic lesion through the modulation of immunity, apoptosis-regulating molecules, and angiogenesis-associated factors, while enhancing the therapeutic effects of western medications in treating endometriosis. Furthermore, pathway and gene ontology analyses demonstrated that GFW might attenuate the disease primarily by affecting AGE-RAGE signaling pathway in diabetic complications (hsa04933) as well as pathways involved in Kaposi sarcoma-associated herpesvirus infection (hsa05167), human cytomegalovirus infection (has05163), and fluid shear stress and atherosclerosis (hsa05418). These pathways were all involved in the regulation of inflammation, angiogenesis, and apoptosis and commonly affected by all herbs.

CONCLUSIONS

The current review revealed that endometriosis is highly associated with aberrant inflammatory, angiogenic, and apoptotic activities. The therapeutic effects of GFW on endometriosis are likely to act through regulating these activities.

Proangiogenic properties of complement protein C1q can contribute to endometriosis

Endometriosis (EM) is defined as the engraftment and proliferation of functional endometrial-like tissue outside the uterine cavity, leading to a chronic inflammatory condition. While the precise etiology of EM remains elusive, recent studies have highlighted the crucial involvement of a dysregulated immune system. The complement system is one of the predominantly altered immune pathways in EM. Owing to its involvement in the process of angiogenesis, here, we have examined the possible role of the first recognition molecule of the complement classical pathway, C1q. C1q plays seminal roles in several physiological and pathological processes independent of complement activation, including tumor growth, placentation, wound healing, and angiogenesis. Gene expression analysis using the publicly available data revealed that C1q is expressed at higher levels in EM lesions compared to their healthy counterparts. Immunohistochemical analysis confirmed the presence of C1q protein, being localized around the blood vessels in the EM lesions. CD68+ macrophages are the likely producer of C1q in the EM lesions since cultured EM cells did not produce C1q in vitro. To explore the underlying reasons for increased C1q expression in EM, we focused on its established pro-angiogenic role. Employing various angiogenesis assays on primary endothelial endometriotic cells, such as migration, proliferation, and tube formation assays, we observed a robust proangiogenic effect induced by C1q on endothelial cells in the context of EM. C1q promoted angiogenesis in endothelial cells isolated from EM lesions (as well as healthy ovary that is also rich in C1q). Interestingly, endothelial cells from EM lesions seem to overexpress the receptor for the globular heads of C1q (gC1qR), a putative C1q receptor. Experiments with siRNA to silence gC1qR resulted in diminished capacity of C1q to perform its angiogenic functions, suggesting that C1q is likely to engage gC1qR in the pathophysiology of EM. gC1qR can be a potential therapeutic target in EM patients that will disrupt C1q-mediated proangiogenic activities in EM.

Research progress of dydrogesterone in the treatment of endometriosis

Endometriosis is a common gynecological disease among women of reproductive age. It is a chronic estrogen and progestin related inflammatory disease. At present, the main treatments for endometriosis are drug therapy and surgery. In drug therapy, progesterone is listed as the first-line recommendation in multinational guidelines. Dydrogesterone, as an oral reversal progesterone, can slow down the metabolism of progesterone, inhibit angiogenesis and extracellular matrix degradation to inhibit the proliferation of the ectopic endometrium, induce the atrophy of the ectopic endometrium through the pro-apoptotic pathway, and treat endometriosis through multiple mechanisms of regulating inflammatory factors to reduce inflammation. Clinically, dydrogesterone treatment of endometriosis can relieve patients' symptoms, promote fertility, be used in combination, and is safe. This article will review the mechanism and clinical application of dydrogesterone in the treatment of endometriosis.

Investigation of the Therapeutic Effect of Salbutamol on Endometriosis in a Mouse Model

Endometriosis is an immune chronic inflammatory disease, and there are currently no more effective drugs for treating endometriosis due to its unknown etiology. Salbutamol is a β2-adrenergic receptor (β2AR) agonist commonly used to treat asthma by selectively activating β2 receptors on airway smooth muscle and leukocytes, exerting bronchial dilation and synergistic anti-inflammatory effects. In recent years, β2AR agonists have been used in endometriosis studies, and we speculate that salbutamol may have a therapeutic effect on endometriosis. The purpose of this research was to explore the therapeutic effect of salbutamol on endometriosis mice. The mouse endometriosis model was established and treated with different doses of salbutamol. Endometrial lesions were harvested for pathological diagnosis, immunohistochemistry (IHC), Masson staining, and toluidine blue analysis. We found that the number and size of endometriotic lesions were all significantly decreased after 3 weeks of treatment with different doses of salbutamol on endometriosis model mice (P < 0.05). After Salbutamol treatment, the amount of mast cells (toluidine blue) and macrophages (F4/80) in the lesions as well as the expressions of interleukin (IL)-1β, tumor necrosis factor (TNF)-ɑ, platelet-derived growth factor subunit B (PDGFB), CD31, transforming growth factor (TGF)-β, Masson staining, BCL2, TUBB3, substance P (SP), and nerve growth factor (NGF) were significantly reduced (P < 0.05). These results suggested that salbutamol could effectively treat endometriosis in mice by reducing immune inflammatory cells and factors, angiogenesis, and fibrosis, increasing apoptosis of endometriotic lesions, and decreasing neurogenesis.

Maternal exposure to dibutyl phthalate (DBP) impairs angiogenesis and AR signalling pathway through suppression of TGFB1I1 in hypospadias offspring

Early exposure to dibutyl phthalate (DBP) can cause hypospadias in newborn foetuses. However, the underlying molecular mechanism is not well defined. Aberrant angiogenesis is associated with various dysplasias including urogenital deficits. In vivo and in vitro angiogenesis assays showed reduced angiogenesis in the hypospadias group and DBP exposed group. RNA-sequencing analysis of DBP-treated HUVECs revealed decreased expression of transforming growth factor beta 1-induced transcript 1 (TGFB1I1) and a significantly enriched angiogenesis-associated pathway. Further experiments revealed that decreased TGFB1I1 expression was associated with disrupted tube formation and migration, which resulted in decreased angiogenesis. Functional assays revealed that the overexpression of TGFB1I1 promoted tube formation and migration of HUVECs in the DBP-treated group. Moreover, we showed that the transcription factor AR was regulated by TGFB1I1 through inhibiting its translocation from the cytoplasm to the nucleus. Together, our results identified TGFB1I1 as a component of aberrant angiogenesis in hypospadias rats and its interaction with AR might be a potential target for hypospadias development.

Kallikrein-Related Peptidase 4 Promotes Proliferation, Migration, Invasion, and Pro-Angiogenesis of Endometrial Stromal Cells via Regulation of Brain-Derived Neurotrophic Factor Production in Endometriosis

Endometriosis is a common benign gynecologic condition. Endometriosis lesions are associated with endometrial cell proliferation, migration, invasion, and neovascularization, while the specific molecular mechanisms are still elusive. Transcriptome sequencing has been used for the identification of diagnostic markers in endometriosis. Here, transcriptome profiling revealed that kallikrein-related peptidase 4 (KLK4) expression was up-regulated in ectopic endometrium (EC) tissues of patients with endometriosis. KLK4 mediates the degradation of extracellular matrix proteins, and its proteolytic activity activates many tumorigenic and metastatic pathways via tumor invasion and migration. Nevertheless, whether KLK4 serves as an important regulatory factor in endometriosis remains unclear. This study confirmed that KLK4 was highly expressed in ectopic endometrial stromal cells (EC-ESCs). KLK4 overexpression promoted proliferation and suppressed apoptosis of EC-ESCs, induced cell migration and invasion, and enhanced angiogenesis in vivo. Mechanistically, KLK4 overexpression mediated the protein cleavage of pro-brain-derived neurotrophic factor in EC-ESCs. Finally, brain-derived neurotrophic factor was a vital downstream substrate of KLK4 maintained the proliferation, metastasis, and pro-angiogenesis abilities and inhibited apoptosis of ESCs through a rescue study. Together, these findings demonstrate the promotive role of KLK4 in endometriosis development. In addition, the study provides a new insight that KLK4 might be a potential therapeutic target and prognostic marker for patients with endometriosis.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

Oxidized LDL promotes EMS-induced angiogenesis by increasing VEGF-A expression and secretion by endometrial cells

BACKGROUND

Endometriosis (EMS) is a "tumour-like" gynaecological disease with distant metastasis, and studies have shown that EMS can induce distant metastasis through vascular vessels, but the driving factors and their mechanism are not clear.

METHODS

We used an EMS animal model and gene knockout technique to explore the role of EMS-induced angiogenesis in EMS metastasis in vivo and in vitro and clarify the role and molecular mechanism of oxLDL in promoting EMS-induced angiogenesis.

RESULTS

We found that microvascular density (MVD) in metastasized ectopic endometrium and eutopic endometrial tissue was higher than that in normal endometrial tissue, and plasma oxLDL was positively correlated with the distant metastasis of EMS. Furthermore, we clarified that oxLDL enhanced the MVD of endometrial tissue by increasing VEGF-A expression and secretion in endometrial cells. Finally, we illustrated the mechanism by which oxLDL promotes VEGF-A expression through the AKT-HIF-1α signalling pathway.

CONCLUSION

OxLDL is a risk factor promoting distant EMS metastasis by increasing VEGF-A expression and secretion through AKT-HIF-1α signalling. This finding may provide theoretical support and therapeutic targets for the clinical prevention and treatment of EMS.

Circulating proteomic profiles associated with endometriosis in adolescents and young adults

STUDY QUESTION

What are the systemic molecular profiles of endometriosis diagnosed in adolescents and young adults?

SUMMARY ANSWER

Significant enrichment and increased activation of proteins related to angiogenesis and cell migration pathways were observed in endometriosis cases compared to controls (P-value < 2.4 × 10-8).

WHAT IS KNOWN ALREADY

Little is known about the pathophysiology of adolescent endometriosis despite the fact that over 50% of adults with endometriosis report onset of severe pelvic pain during adolescence.

STUDY DESIGN, SIZE, DURATION

A cross-sectional analysis using data on 142 laparoscopically confirmed endometriosis cases and 74 controls from the observational longitudinal cohort of Women's Health Study: From Adolescence to Adulthood (A2A).

PARTICIPANTS/MATERIALS, SETTING, METHODS

We measured 1305 plasma protein levels using the validated, multiplex aptamer-based proteomics discovery platform, SOMAscan. We calculated odds ratios and 95% CIs using logistic regression adjusting for age, BMI, fasting status and hormone use at blood draw for differentially expressed proteins (P < 0.05). Ingenuity Pathway Analysis and STRING analysis were performed to identify biological pathways and protein interactions. We also examined proteins and pathways associated with superficial peritoneal lesion colors (i.e. red, vascularized, white, blue/black, brown).

MAIN RESULTS AND THE ROLE OF CHANCE

Average age at blood draw was 18 years for endometriosis cases and 22 years for controls. We identified 63 proteins associated with endometriosis with type-I error set at 0.05, and absolute fold change >1.2, revealing significant enrichment of dysregulated proteins in biological pathways associated with endometriosis. Increased activation of pathways related to angiogenesis and cell migration was observed in plasma from endometriosis cases compared to controls (P-value < 2.4 × 10-8). Furthermore, when we examined proteins and pathways associated with lesion colors, vascularized lesions were associated with upregulation of pathways related to immune cell migration/activation and inflammation, whereas white, blue/black and brown lesions were associated with downregulation of these pathways.

LIMITATIONS, REASONS FOR CAUTION

Validation of our results in independent datasets and mechanistic studies are warranted to further our understanding of the pathophysiological characteristics of this common but understudied patient population.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this was the first study to comprehensively examine circulating proteins in predominantly adolescents and young adult women with and without endometriosis. Results from this study provide novel biological insight that will build toward further research to elucidate endometriosis pathophysiology during the earlier course of the disease trajectory.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Department of Defense (W81XWH1910318) and the 2017 Boston Center for Endometriosis Trainee Award. Financial support for establishment of and data collection within the A2A cohort were provided by the J. Willard and Alice S. Marriott Foundation. N.S., A.F.V., S.A.M., K.L.T. have received funding from Marriott Family Foundation. S.A.M. and K.L.T. are supported by NICHD (R01 HD94842). S.A.M. serves as an advisory board member for AbbVie and Roche; neither are related to this study. The authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Altered gene expression of VEGF, IGFs and H19 lncRNA and epigenetic profile of H19-DMR region in endometrial tissues of women with endometriosis

Background

Endometriosis, as chronic estrogen-dependent disease, is defined by the presence of endometrial-like tissue outside the uterus. Proliferation of endometrial tissue and neoangiogenesis are critical factors in development of endometriosis. Hence, vascular endothelial growth factor (VEGF) as well as insulin‐like growth factor 1 and 2 (IGF1, 2) may be involved as inducers of cellular proliferation or neoangiogenesis. Imprinted long noncoding RNA H19 (lncRNA H19) has been suggested to be involved in pathogenesis of endometriosis via regulation of cellular proliferation and differentiation. Epigenetic aberrations appear to play an important role in its pathogenesis. The present study was designed to elucidate VEGF, IGF1, IGF2 and H19 lncRNA genes expression and epigenetic alterations of differentially methylated region (DMR) of H19 (H19-DMR) regulatory region in endometrial tissues of patients with endometriosis, in comparison with control women.

Methods

In this case–control study, 24 women with and without endometriosis were studied for the relative expression of VEGF, IGF1, IGF2 and H19 lncRNA genes using real-time polymerase chain reaction (PCR) technique. Occupancy of the MeCP2 on DMR region of H19 gene was assessed using chromatin immunoprecipitation (ChIP), followed by real-time PCR.

Results

Genes expression profile of H19, IGF1 and IGF2 was decreased in eutopic and ectopic endometrial tissues of endometriosis group, compared to the control tissues. Decreased expression of H19 in ectopic samples was significant in comparison with the controls (P < 0.05). Gene expression of VEGF was increased in eutopic tissues of endometriosis group, compared to control group. Whereas its expression level was lower in ectopic lesions versus eutopic and control endometrial samples. ChIP analysis revealed significant and nearly significant hypomethylation of H19-DMR region II in eutopic and ectopic samples, compared to the control group respectively. This epigenetic change was aligned with expression of IGF2. While methylation of H19-DMR region I was not significantly different between the eutopic, ectopic and control endometrial samples.

Conclusion

These data showed that VEGF, IGF1, IGF2 and H19 lncRNA genes expression and epigenetic alterations of H19 lncRNA have dynamic role in the pathogenesis of endometriosis, specifically in the way that hypomethylation of H19-DMR region II can be involved in IGF2 dysregulation in endometriosis.

Immunology and Immunotherapy of Endometriosis

Endometriosis is one of the most common gynecological and systemic diseases, with a remarkable immune background. Patients suffer from pain and fertility reduction. Due to the distinct immune component, an immunotherapeutic approach may gain importance in the future. In endometriosis, shifts in the cell fractions of the immune system are well known. Moreover, hypoxia concomitant with inflammation causes a disturbed immune response. The removal of endometriosis has a therapeutic effect, normalizes the immune disorders, and remains the most effective causative treatment in terms of pain and infertility. A key issue is whether a similar effect can be achieved for fertility with non-invasive immunotherapy where surgery is inadvisable or cannot be performed for various reasons. Numerous immunotherapy trials, including vaccines, were conducted on animals only, although the research is encouraging. Among the promising methods of non-specific immunotherapy is the administration of an ethiodized oil contrast. Moreover, due to the significant successes of immunotherapy in oncology, the possibility of immunotherapy affecting NK cells has been postulated. NK cells are responsible for the surveillance and apoptosis of ectopic cells. Expanding the arsenal of endometriosis treatment by immunotherapy is promising due to the significant contribution of immunological factors and the limitations of current treatment methods.

Endometriosis: Epidemiology, Classification, Pathogenesis, Treatment and Genetics (Review of Literature)

Endometriosis is a “mysterious” disease and its exact cause has not yet been established. Among the etiological factors, congenital, environmental, epigenetic, autoimmune and allergic factors are listed. It is believed that the primary mechanism of the formation of endometriosis foci is retrograde menstruation, i.e., the passage of menstrual blood through the fallopian tubes into the peritoneal cavity and implantation of exfoliated endometrial cells. However, since this mechanism is also observed in healthy women, other factors must also be involved in the formation of endometriosis foci. Endometriosis is in many women the cause of infertility, chronic pain and the deterioration of the quality of life. It also represents a significant financial burden on health systems. The article presents a review of the literature on endometriosis—a disease affecting women throughout the world.

M1 Macrophage-Derived Nanovesicles Repolarize M2 Macrophages for Inhibiting the Development of Endometriosis

Background

Endometriosis is a common nonmalignant gynecological disorder that affects 10–15% women of reproductive age and causes several symptoms that result in decreased quality of life and a huge social burden. In recent decades, extracellular vesicles (EVs) have gained attention as a potential therapeutic tool; however, the therapeutic effects of EVs against endometriosis have not been reported. Accordingly, in this study, we investigated the feasibility of nanovesicles (NVs) derived from M1 macrophages (M1NVs) in treating endometriosis.

Methods

M1NVs were prepared by serial extrusion. Co-culture assays were performed to investigate changes in tube formation and migration/invasion of eutopic endometrial stroma cells (ESCs) obtained from patients with endometriosis (EM-ESCs). A mouse model of endometriosis was established, and mice were treated with phosphate-buffered saline, M0NVs, or M1NVs to evaluate the efficacy and safety of M1NV for treating endometriosis.

Results

M1NVs directly or indirectly inhibited the migration and invasion of EM-ESCs and reduced tube formation. In the mouse model, M1NVs suppressed the development of endometriosis through reprogramming of M2 macrophages, without causing damage to the organs.

Conclusions

M1NVs inhibit the development of endometriosis directly, or through repolarizing macrophages from M2 to M1 phenotype. Hence, administration of M1NVs may represent a novel method for the treatment of endometriosis.

The Effect of Novel Medical Nonhormonal Treatments on the Angiogenesis of Endometriotic Lesions

Importance

Irrespective of the precise mechanisms leading to endometriosis, angiogenesis is essential for the establishment and long-term proliferation of the disease. As current surgical and medical management options for women with endometriosis have substantial drawbacks and limitations, novel agents are needed and molecules targeting the angiogenic cascade could serve as potential candidates.

Objective

Our aim was to review current data about the role of angiogenesis in the pathophysiology of endometriosis and summarize the novel antiangiogenic agents that could be potentially used in clinical management of patients with endometriosis.

Evidence Acquisition

Original research and review articles were retrieved through a computerized literature search.

Results

Loss of balance between angiogenic activators and suppressors triggers the nonphysiological angiogenesis observed in endometriotic lesions. Several proangiogenic mediators have been identified and most of them have demonstrated increased concentrations in the peritoneal fluid and/or serum of women with endometriosis. Among the antiangiogenic molecules, anti-vascular endothelial growth factor agents, dopamine agonists, romidepsin, and statins have shown the most promising results so far.

Conclusions and Relevance

Given the limitations of current treatments of endometriosis, there is a need for novel, more efficient agents. Antiangiogenic molecules could be used potentially in clinical management of women with endometriosis; however, their safety and efficiency should be carefully assessed prior to that. Further large prospective trials in humans are needed before any treatment is introduced into daily clinical practice.

A Reassessment of the Therapeutic Potential of a Dopamine Receptor 2 Agonist (D2-AG) in Endometriosis by Comparison against a Standardized Antiangiogenic Treatment

Dopamine receptor 2 agonists (D2-ags) have been shown to reduce the size of tumors by targeting aberrant angiogenesis in pathological tissue. Because of this, the use of a D2-ag was inferred for endometriosis treatment. When assayed in mouse models however, D2-ags have been shown to cause a shift of the immature vessels towards a more mature phenotype but not a significant reduction in the amount of vascularization and size of lesions. These has raised concerns on whether the antiangiogenic effects of these compounds confer a therapeutic value for endometriosis. In the belief that antiangiogenic effects of D2-ags in endometriosis were masked due to non-optimal timing of pharmacological interventions, herein we aimed to reassess the antiangiogenic therapeutic potential of D2-ags in vivo by administering compounds at a timeframe in which vessels in the lesions are expected to be more sensitive to antiangiogenic stimuli. To prove our point, immunodeficient (NU/NU) mice were given a D2-ag (cabergoline), anti-VEGF (CBO-P11) or vehicle (saline) compounds (n = 8 per group) starting 5 days after implantation of a fluorescently labeled human lesion. The effects on the size of the implants was estimated by monitoring the extent of fluorescence emitted by the lesion during the three-week treatment period. Subsequently mice were sacrificed and lesions excised and fixed for quantitative immunohistochemical/immunofluorescent analysis of angiogenic parameters. Lesion size, vascular density and innervation were comparable in D2-ag and anti-VEGF groups and significantly decreased when compared to control. These data suggest that D2-ags are as powerful as standard antiangiogenic compounds in interfering with angiogenesis and lesion size. Our preliminary study opens the way to further exploration of the mechanisms beneath the antiangiogenic effects of D2-ags for endometriosis treatment in humans.

Protein kinase CK2 participates in estrogen-mediated endothelial progenitor cell homing to endometriotic lesions through stromal cells in a stromal cell-derived factor-1- CXCR4-dependent manner

OBJECTIVE

To explore the possible mechanism of protein kinase CK2, which participates in estrogen recruitment of endothelial progenitor cells (EPCs), and its role in the angiogenesis of endometriosis lesions.

DESIGN

Laboratory study.

SETTING

University.

ANIMAL(S)

BALB/c mice.

INTERVENTION(S)

Exposure of human endometrial stromal cells (HESCs) to estrogen and CK2 inhibitor CX-4945 and endometrial stromal cells transfected with the protein kinase CK2 vector (HESC-CK2). Endometriosis models were induced by allogeneic mice transplantation of the endometrium into dorsal skinfold chambers. The mice received an IP injection of 50 mg/kg emodin per day or were treated with 100 μg/kg estrogen by SC injection once a week.

MAIN OUTCOME MEASURE(S)

The concentration of cytokines in cells was measured with ELISA. The migration of EPCs was examined using the scratch assay method and Transwell, a capillary tube-formation assay to determine EPC tube-forming capacity, and protein and mRNA expression with Western blot and polymerase chain reaction analyses, respectively.

RESULT(S)

Protein kinase CK2 participates in estrogen-mediated EPC homing to endometriotic lesions through stromal cells in a stromal cell-derived factor-1 (SDF-1)-CXCR4-dependent manner. Conditioned medium from endometrial stromal cells that were stably transfected with the protein kinase CK2 vector (HESC-CK2) or pretreated with estrogen significantly enhanced the migration and recruitment of EPCs. In contrast, conditioned medium from HESCs that were treated with CX-4945, a selective inhibitor of CK2, inhibited the mobility and viability of EPCs. Furthermore, CK2 overexpression significantly upregulated SDF-1 expression and secretion in endometrial stromal cells by activating the AKT/mTOR pathway. Moreover, treatment with the SDF-1 receptor CXCR4-specific inhibitor AMD3100 completely reversed the CK2-enhanced migration of EPCs.

CONCLUSION(S)

This study demonstrates that CK2 participates in estrogen-mediated EPC homing to endometriotic lesions through stromal cells in an SDF-1-CXCR4-dependent manner and may be a therapeutic target.

The regression of endometriosis with glycosylated flavonoids isolated from Melilotus officinalis (L.) Pall. in an endometriosis rat model

OBJECTIVE

Melilotus officinalis (L.) Pall. is commonly used for treating bronchitis, painful menstruation, hemorrhoids, kidney stones, ulcers of the eyes, earache, and hardening and swelling of uterus. The European Medicines Agency reported the use of M. officinalis orally against stomach ache, gastric ulcer, and disorders of the liver and uterus in folk medicine. The present study aimed to appraise the activity of M. (L.) Pall. aerial parts in endometriosis rat model.

MATERIALS AND METHODS

The endometriosis rat model was used to evaluate the potential activity of M. officinalis aerial parts based on its folkloric usage. The aerial parts of M. officinalis were extracted with n-hexane, ethyl acetate (EtOAc), and methanol (MeOH), respectively. The adhesion scores, endometrial foci areas, and cytokine levels were measured in all treated groups. After the biological activity studies, phytochemical studies were performed on the active extract and the fractions obtained from the active extract.

RESULTS

The MeOH extract significantly decreased the endometrial foci areas and cytokine levels in rats with endometriosis. Fractionation was performed on the MeOH extract to achieve bioactive molecules. Following the fractionation, the fractions obtained from the MeOH extract were tested. Fraction C showed the highest activity in the rat endometriosis model. Phytochemical investigation of the active fraction (Fraction C) resulted in isolation and elucidation of some quercetin and kaempferol glucoside derivatives.

CONCLUSION

Fraction C obtained from the MeOH extract of M. officinalis showed the highest activity, yielding four glycosylated flavonoids.

Focal adenomyosis of the outer myometrium and deep infiltrating endometriosis severity

OBJECTIVE

To determine whether the presence of focal adenomyosis of the outer myometrium (FAOM) at preoperative magnetic resonance imaging is associated with the severity of deep infiltrating endometriosis.

DESIGN

Observational cross-sectional study involving 255 symptomatic deep infiltrating endometriosis patients. Comparisons were performed according to the presence of FAOM.

SETTING

University hospital.

PATIENT(S)

Women with a preoperative magnetic resonance imaging and complete surgical exeresis of endometriotic lesions with histologically documented deep infiltrating endometriosis.

INTERVENTION(S)

Surgical management for deep infiltrating endometriosis.

MAIN OUTCOME MEASURE(S)

The presence of multiple deep infiltrating endometriosis lesions, the mean number and location of deep infiltrating endometriosis lesions, and the mean total revised American Society for Reproductive Medicine scores.

RESULT(S)

The prevalence of FAOM at preoperative magnetic resonance imaging in the 255 patients with deep infiltrating endometriosis was 56.5%. The mean number of deep infiltrating endometriosis lesions was significantly higher in the FAOM(+) group than in the FAOM(-) group: 3.5 ± 2.1 vs. 2.2 ± 1.5. The mean total revised American Society for Reproductive Medicine score was higher in case of FOAM coexisting with deep infiltrating endometriosis. After adjusting for confounding factors, the presence of FAOM was significantly associated with multiple deep lesions.

CONCLUSION(S)

FAOM was significantly associated with greater deep infiltrating endometriosis severity. This needs to be integrated into the management strategy. Furthermore, a pathogenic link between deep infiltrating endometriosis and FAOM cannot be excluded.

Supplementation with vitamin D or ω-3 fatty acids in adolescent girls and young women with endometriosis (SAGE): a double-blind, randomized, placebo-controlled trial

BACKGROUND

Adolescents with endometriosis are a particularly underserved population who struggle with chronic pain. Despite widespread use, there are no published trials examining the individual effects of vitamin D and omega-3 (n-3) fatty acid supplementation on endometriosis-associated pain in adolescents.

OBJECTIVES

We aimed to determine whether supplementation with vitamin D or ω-3 fatty acids remediates pain, changes frequency of pain medication usage, or affects quality of life in young women with endometriosis.

METHODS

Women (aged 12-25 y) with surgically confirmed endometriosis and pelvic pain enrolled in a double-blind, randomized, placebo-controlled trial. The primary outcome was pain measured by the visual analog scale (VAS). Secondary outcomes were quality of life, pain catastrophizing, and pain medication usage. Participants were randomly assigned to receive 2000 IU vitamin D3, 1000 mg fish oil, or placebo daily for 6 mo.

RESULTS

A total of 147 women were screened and 69 were randomly assigned as follows: 27 to vitamin D3; 20 to fish oil; and 22 to placebo. Participants in the vitamin D arm experienced significant improvement in VAS pain [mean (95% CI) worst pain in the past month, from baseline to 6 mo: 7.0 (6.2, 7.8) to 5.5 (4.2, 6.8), P = 0.02]; however, an improvement of nearly identical magnitude was observed in the placebo arm [6.0 (5.1, 6.9) to 4.4 (3.0, 5.8), P = 0.07]. A more modest improvement was observed in the fish oil arm [5.9 (4.8, 7.0) to 5.2 (3.7, 6.8), P = 0.39]. Neither of the intervention arms were statistically different from placebo.

CONCLUSIONS

In young women with endometriosis, supplementation with vitamin D led to significant changes in pelvic pain; however, these were similar in magnitude to placebo. Supplementation with fish oil resulted in about half of the VAS pain reduction of the other 2 arms. Studies are needed to better define the physiology underlying the observed reduction in pain score in the placebo arm that persisted across 6 mo.This trial was registered at clinicaltrials.gov as NCT02387931.

Impact of Bevacizumab on Experimentally Induced Endometriotic Lesions: Angiogenesis, Invasion, Apoptosis, and Cell Proliferation

Endometriosis is responsible for pain symptoms with great impact on the patient's quality of life. Several medication lines have been studied aiming at its definitive treatment. Among them, angiogenesis inhibitor factors may be effective given that angiogenesis has fundamental role in the establishment and growth of endometriotic lesions. In this study, we investigated the influence of bevacizumab, anti-factor drug of endothelial growth (anti-VEGF), used at two different dosages, in experimental endometriosis induced in rats. After the induction of endometriosis lesions in rats, they were divided in 3 groups: control group, no treatment, and two other groups were treated with different dosages of the same medication for 4 weeks. At the end of the treatment, endometriotic lesions were removed and evaluated regarding area of lesions, presence of endometrial tissue in microscopy, positivity for anti-VEGF antibody in immunohistochemistry, and gene expression of Pcna, Mmp9, Tp63, and Vegfa. Bevacizumab acted by reducing the area of lesions in the groups that received medication (p = 0.002) and reducing gene expression to Tp63 in lesions (p = 0.04). There was no significant result in other evaluations. We observed that there was significant reduction of the area of lesions among groups, suggesting that bevacizumab has a positive effect on disease control. The gene expression of Tp63 was significantly lower in the group that received high dose of the drug when compared with the other two groups; therefore, we concluded that bevacizumab acts by reducing cell proliferation and differentiation in lesions, constituting a real option for treating endometriosis.

Eutopic stromal cells of endometriosis promote neuroangiogenesis via exosome pathway†

Endometriosis is a common multifactorial gynecological disorder defined as the proliferation of endometrial tissue outside of the uterine cavity. Neuroangiogenesis (co-recruitment of nerves and blood vessels) is believed to play an integral part in the establishment and growth of endometriotic lesions. We hypothesized that exosomes derived from abnormal endometrium may serve as the second identifier of endometriosis and play an important role in the development of endometriosis by regulating neuroangiogenesis. Primary human endometrial stromal cells (ESCs) were isolated from eutopic endometrium (EmESC, n = 22) with endometriosis and normal endometrium (CoESC, n = 6). Exosomes were isolated from ESCs using the "standard" ultracentrifugation method, and the characterization of exosomes was identified through transmission electron microscopy, nanoparticle tracking analysis, and western blot. The role of exosomes in regulating neuroangiogenesis was determined through in vitro tube formation assay, neurite outgrowth assay, and dorsal root ganglion (DRG) neuron apoptosis analysis. The data showed that EmESCs could secrete exosomes with a diameter of approximately 100 nm and a biconcave morphological feature; they were internalized by human umbilical vein endothelial cells and DRG neurons and enhanced neuroangiogenic effects. We further validated the role of exosomes through blocking experiments. We found that when the exosome secretion was blocked, the pro-neuroangiogenesis effects were decreased. In conclusion, these data suggested that exosomes may play a key role in endometriosis by promoting neuroangiogenesis.

Immunomodulatory effects of vitamin D3 on gene expression of MDGF, EGF and PDGFB in endometriosis

RESEARCH QUESTION

Endometriosis, an inflammatory disease, is assumed to be associated with an increased production of growth-related cytokines. Based on the emerging immunomodulatory role of vitamin D3 in different inflammatory conditions, this study aimed to examine its modulatory effect on the expression levels of the genes for platelet-derived growth factor-B (PDGFB), monocyte/macrophage-derived growth factor (MDGF, also known as PPBP) and epidermal growth factor (EGF) in peritoneal fluid mononuclear cells (PFMC) in women with and without endometriosis.

DESIGN

PFMC from 10 women with endometriosis and 10 control participants were treated with vitamin D3.The gene expression levels of PDGFB, MDGF and EGF were measured 6, 24 and 48 h following vitamin D3 administration using real-time PCR.

RESULTS

Gene expression levels of EGF and PDGFB were higher in the PFMC of women with endometriosis than the control group (P = 0.006, P < 0.001, respectively). Although MDGF expression showed an increase in the endometriosis group compared with non-endometriotic controls, no significant difference was found. Vitamin D3 significantly decreased EGF expression at 6, 24 and 48 h (P < 0.001, P < 0.001 and P = 0.007, respectively), MDGF at 24 and 48 h (P < 0.001 and P = 0.009, respectively) and PDGFB at 6 h (P = 0.047) in the endometriosis group. Vitamin D3 treatment had no significant effect on expression of the genes in the PFMC of non-endometriotic women.

CONCLUSIONS

The study concluded that PDGFB and EGF gene expression increases in endometriosis, and vitamin D3 could markedly decrease this expression, suggesting its therapeutic potential in endometriosis.

CXCR4 or CXCR7 antagonists treat endometriosis by reducing bone marrow cell trafficking

Adult stem cells have a major role in endometrial physiology, including remodelling and repair. However, they also have a critical role in the development and progression of endometriosis. Bone marrow-derived stem cells engraft eutopic endometrium and endometriotic lesions, differentiating to both stromal and epithelial cell fates. Using a mouse bone marrow transplantation model, we show that bone marrow-derived cells engrafting endometriosis express CXCR4 and CXCR7. Targeting either receptor by the administration of small molecule receptor antagonists AMD3100 or CCX771, respectively, reduced BM-derived stem cell recruitment into endometriosis implants. Endometriosis lesion size was decreased compared to vehicle controls after treatment with each antagonist in both an early growth and established lesion treatment model. Endometriosis lesion size was not effected when the local effects of CXCL12 were abrogated using uterine-specific CXCL12 null mice, suggesting an effect primarily on bone marrow cell migration rather than a direct endometrial effect. Antagonist treatment also decreased hallmarks of endometriosis physiopathology such as pro-inflammatory cytokine production and vascularization. CXCR4 and CXCR7 antagonists are potential novel, non-hormonal therapies for endometriosis.

Dopamine agonists as genital endometriosis target therapy

OBJECTIVE

The present study was to find a pathogenic evidence for dopamine agonist application in patients with endometriosis associated pain syndrome.

PATIENTS AND TECHNIQUE

The study involved 227 patients of reproductive age with histologically confirmed genital endometriosis (GE) of I-III degree according to ASRM classification. The control group included 12 women with no laparoscope detected gynecologic pathology. The levels of prolactin (PRL), peripheral blood (PB), and peritoneal fluid (PF) were evaluated by chemiluminescence immune assay. The pain syndrome was measured by McGill visual analogue scale. Statistica10 program (StatSoft, Inc., Tulsa, OK) was applied for obtained data processing.

RESULTS

A correlation was established between GE rate and levels of PRL and PB (Rs = 0.28, p < .05) as well as a correlation of PRL in PB and PF (Rs = 0.29, p < .05). Patients receiving cabergoline combined with hormone therapy standard schemes manifested considerable pain syndrome relief.

CONCLUSIONS

PRL involvement in GE pathogenesis and more intense therapeutic impact on pain syndrome in case of combined administration of dopamine and standard hormone therapy prove cabergoline application in clinical practice.

Effect of endometriosis on the fecal bacteriota composition of mice during the acute phase of lesion formation

Accumulating evidence indicates that there is an interaction between the gut microbiota and endometriotic lesions. The new formation of these lesions is associated with stem cell recruitment, angiogenesis and inflammation, which may affect the composition of the gut microbiota. To test this hypothesis, we herein induced endometriotic lesions by transplantation of uterine tissue fragments from green fluorescent protein (GFP)⁺ donor mice into the peritoneal cavity of GFP^- C57BL/6 wild-type mice. Sham-transplanted animals served as controls. Fecal pellets of the animals were collected 3 days before as well as 7 and 21 days after the induction of endometriosis to analyze the composition of the gut microbiota by means of 16S ribosomal RNA gene sequencing. The transplantation of uterine tissue fragments resulted in the establishment of endometriotic lesions in all analyzed mice. These lesions exhibited a typical histomorphology with endometrial glands surrounded by a vascularized stroma. Due to their bright GFP signal, they could be easily differentiated from the surrounding GFP^- host tissue. Bacterial 16S rRNA genes were successfully PCR-amplified from the DNA extracts of all obtained mice fecal samples. However, no significant effect of endometriosis induction on the composition of the bacterial microbiota was detected with our experimental setup. Our findings allow careful speculation that endometriosis in mice does not induce pronounced dysbiosis during the acute phase of lesion formation.

Positron emission tomography imaging of vascular endothelial growth factor with 64Cu-labeled bevacizumab for non-invasive diagnosis of endometriosis

Introduction:

Non-invasive diagnosis of endometriosis remains challenging. A promising approach for diagnosing endometriosis is the molecular imaging of vascular endothelial growth factor because angiogenesis plays a role in the establishment of endometriosis. This study aimed to evaluate the potential of copper-64-labeled bevacizumab, an anti–vascular endothelial growth factor antibody, for endometriosis imaging.

Methods:

Mouse endometriosis model was prepared by autologous transplantation. The vascular endothelial growth factor expression was evaluated by immunohistochemical staining. Biodistribution study and positron emission tomography imaging were performed at 1, 24, and 48 h after the injection of radiolabeled bevacizumab.

Results:

The immunohistochemical staining revealed that vascular endothelial growth factor is expressed around the stroma and glandular epithelial cells in the endometriosis lesion. The biodistribution study showed a high uptake of indium-111 bevacizumab in the endometriosis lesion. Positron emission tomography imaging with copper-64-labeled bevacizumab clearly visualized the endometriosis lesions at 24 and 48 h after injection.

Conclusion:

These results indicate the potential usefulness of copper-64-labeled bevacizumab for endometriosis imaging.

Endothelial Cell Development and Its Application to Regenerative Medicine

The formation and remodeling of a functional circulatory system is critical for sustaining prenatal and postnatal life. During embryogenesis, newly differentiated endothelial cells require further specification to create the unique features of distinct vessel subtypes needed to support tissue morphogenesis. In this review, we explore signaling pathways and transcriptional regulators that modulate endothelial cell differentiation and specification, as well as applications of these processes to stem cell biology and regenerative medicine. We also summarize recent technical advances, including the growing utilization of single-cell sequencing to study vascular heterogeneity and development.

MiR-210-3p protects endometriotic cells from oxidative stress-induced cell cycle arrest by targeting BARD1

Endometriosis is associated with benign but adversely developed cysts in the extrauterine environment. The oxidative imbalanced environment induces DNA damage and affects cell cycle progression of endometrial stromal cells (ESCs) and endometrial epithelial cells, but how endometriotic cells maintain proliferation in the presence of oxidative stress is not clear. Growing evidence has indicated that the ectopic hypoxic microenvironment and oxidative stress can stimulate the growth of endometriotic cells, which is mainly due to the increase of HIF-1α. We found that the master hypoxia-associated miRNA miR-210-3p was increased in stromal and glandular cells of ectopic lesions compared with that of eutopic and normal endometria and was consistent with the expression of HIF-1α and the local oxidative stress-induced DNA damage predictor 8-OHdG. Moreover, miR-210-3p was upregulated in ESCs and Ishikawa cells under hypoxic conditions but not in normoxic culture. Knockdown of miR-210-3p induced a G2/M arrest of ESCs and Ishikawa cells under hypoxia, while no effect was found under normoxia. BARD1 was identified as a target of miR-210-3p. BARD1 expression was decreased in endometriotic tissues compared with eutopic and normal endometria and negatively correlated with the expression of miR-210-3p. Multivariate regression analysis showed that BARD1 downregulation could serve as an indicator for endometriotic severity. Our results suggest that miR-210-3p attenuates the G2/M cell cycle checkpoint by inactivating BRCA1 complex function in response to DNA damage under hypoxia via targeting the 3′ untranslated region of BARD1 mRNA. Endometriotic mouse model experiments showed that intraperitoneal injection of the miR-210-3p inhibitor or vitamin C suppressed the growth of endometriotic lesions. Together, our results demonstrate that endometriotic cells inhibit BARD1/BRCA1 function by upregulating miR-210-3p, which might be the underlying mechanism for endometriotic cell maintenance of growth in oxidative stress. Furthermore, inhibition of miR-210-3p and administration of vitamin C are promising approaches for the treatment of endometriosis.

Developments with 3D bioprinting for novel drug discovery

Introduction: Although there have been significant contributions from the pharmaceutical industry to clinical practice, several diseases remain unconquered, with the discovery of new drugs remaining a paramount objective. The actual process of drug discovery involves many steps including pre-clinical and clinical testing, which are highly time- and resource-consuming, driving researchers to improve the process efficiency. The shift of modelling technology from two-dimensions (2D) to three-dimensions (3D) is one of such advancements. 3D Models allow for close mimicry of cellular interactions and tissue microenvironments thereby improving the accuracy of results. The advent of bioprinting for fabrication of tissues has shown potential to improve 3D culture models. Areas covered: The present review provides a comprehensive update on a wide range of bioprinted tissue models and appraise them for their potential use in drug discovery research. Expert opinion: Efficiency, reproducibility, and standardization are some impediments of the bioprinted models. Vascularization of the constructs has to be addressed in the near future. While much progress has already been made with several seminal works, the next milestone will be the commercialization of these models after due regulatory approval.

Decreased Expression of HOXA10 May Activate the Autophagic Process in Ovarian Endometriosis

Autophagy is a survival process that maintains homeostasis in all eukaryotic cells. Recent studies show an abnormal autophagic activity in endometriosis, but the role of autophagy is controversial. Homeobox A10 (HOXA10) is a transcription factor necessary for embryonic and adult uterine development, and studies indicate that its expression decreases in endometriosis. Homeobox A10 may negatively regulate autophagy in endometriosis. To test this hypothesis, we measured the expression levels of autophagic biomarkers (beclin-1 and LC3-II) and HOXA10 proteins by Western blotting and messenger RNA (mRNA) by quantitative real-time polymerase chain reaction. Furthermore, we evaluated the serum cancer antigen 125 (CA125) levels by immunoassay. Most tested autophagic biomarker proteins and mRNAs were upregulated, whereas HOXA10 protein and mRNA were decreased in ovarian endometriomas compared with eutopic endometria of women with endometriosis and normal endometria. Compared with normal endometrium, only protein expression levels of autophagic biomarkers were increased in the eutopic endometrium of women with endometriosis. Moreover, HOXA10 was found to have a significant negative correlation with autophagy ( P < .01). Serum CA125 was at a high level in endometriosis and increased with elevated revised American Fertility Society staging (I-IV). There was a significant positive correlation between serum CA125 level and LC3-II protein level and/or LC3-II/LC3-I ratio ( P < .01) and a significant negative correlation between serum CA125 level and HOXA10 gene level ( P < .01). In conclusion, our studies support that the deficiency of HOXA10 may induce autophagy in endometriosis, and the relationship among CA125, autophagy, and HOXA10 in endometriosis requires additional research.

G-Protein-Coupled Receptor CXCR7 Is Overexpressed in Human and Murine Endometriosis

Endometriosis is a chronic inflammatory disease. Dysfunctional regulation of chemokines and chemokine receptors is a crucial aspect of endometriosis pathogenesis. Chemokine G-protein-coupled receptors (GPCRs) are important drug targets that regulate inflammation and immunity. Recently, CXCR7, a C-X-C motif containing GPCR, has been identified as a receptor for chemokine ligand CXCL12, one of the best characterized chemokines for cell trafficking, angiogenesis, and cell proliferation in cancer and inflammation. Here, we investigated the expression and localization of CXCR7 in human endometriosis and a murine model of the disease. Normal endometrial epithelium and stroma showed undetectable or very low expression of CXCR7, without any significant changes across phases of the menstrual cycle in humans. CXCR7 is significantly upregulated in endometriosis, showing higher staining in glands and in associated vessels. The mouse model recapitulated the human findings. In conclusion, overexpression of CXCR7 in different cellular populations of endometriosis microenvironment may play a role in the pathogenesis and represent a novel target for treatment.

Basic mechanisms of vascularization in endometriosis and their clinical implications

BACKGROUND

Vascularization is a major hallmark in the pathogenesis of endometriosis. An increasing number of studies suggests that multiple mechanisms contribute to the vascularization of endometriotic lesions, including angiogenesis, vasculogenesis and inosculation.

OBJECTIVE AND RATIONALE

In this review, we provide an overview of the basic mechanisms of vascularization in endometriosis and give special emphasis on their future clinical implications in the diagnosis and therapy of the disease.

SEARCH METHODS

Literature searches were performed in PubMed for English articles with the key words 'endometriosis', 'endometriotic lesions', 'angiogenesis', 'vascularization', 'vasculogenesis', 'endothelial progenitor cells' and 'inosculation'. The searches included both animal and human studies. No restriction was set for the publication date.

OUTCOMES

The engraftment of endometriotic lesions is typically associated with angiogenesis, i.e. the formation of new blood vessels from pre-existing ones. This angiogenic process underlies the complex regulation by angiogenic growth factors and hormones, which activate intracellular pathways and associated signaling molecules. In addition, circulating endothelial progenitor cells (EPCs) are mobilized from the bone marrow and recruited into endometriotic lesions, where they are incorporated into the endothelium of newly developing microvessels, referred to as vasculogenesis. Finally, preformed microvessels in shed endometrial fragments inosculate with the surrounding host microvasculature, resulting in a rapid blood supply to the ectopic tissue. These vascularization modes offer different possibilities for the establishment of novel diagnostic and therapeutic approaches. Angiogenic growth factors and EPCs may serve as biomarkers for the diagnosis and classification of endometriosis. Blood vessel formation and mature microvessels in endometriotic lesions may be targeted by means of anti-angiogenic compounds and vascular-disrupting agents.

WIDER IMPLICATIONS

The establishment of vascularization-based approaches in the management of endometriosis still represents a major challenge. For diagnostic purposes, reliable angiogenic and vasculogenic biomarker panels exhibiting a high sensitivity and specificity must be identified. For therapeutic purposes, novel compounds selectively targeting the vascularization of endometriotic lesions without inducing severe side effects are required. Recent progress in the field of endometriosis research indicates that these goals may be achieved in the near future.

Notch signaling controls sprouting angiogenesis of endometriotic lesions

Angiogenesis is essential for the engraftment and growth of endometriotic lesions. In this study, we analyzed whether this process is regulated by Notch signaling. Endometriotic lesions were induced by endometrial tissue transplantation into dorsal skinfold chambers of C57BL/6 mice, which were treated with the γ-secretase inhibitor DAPT or vehicle. Vascularization, morphology, and proliferation of the newly developing lesions were analyzed using intravital fluorescence microscopy, histology, and immunohistochemistry over 14 days. Inhibition of Notch signaling by DAPT significantly increased the number of angiogenic sprouts within the endometrial grafts during the first days after transplantation when compared to vehicle-treated controls. This was associated with an accelerated vascularization, as indicated by a higher functional microvessel density of DAPT-treated lesions on day 6. However, inhibition of Notch signaling did not affect the morphology and proliferating activity of the lesions, as previously described for tumors. Both DAPT- and vehicle-treated lesions finally consisted of cyst-like dilated glands, which were surrounded by a well-vascularized stroma and contained comparable numbers of proliferating cell nuclear antigen-positive cells. These findings demonstrate that sprouting angiogenesis in endometriotic lesions is controlled by Notch signaling. However, inhibition of Notch signaling does not have beneficial therapeutic effects on lesion development.

Combination therapy with telmisartan and parecoxib induces regression of endometriotic lesions

BACKGROUND AND PURPOSE

Telmisartan suppresses the development of endometriotic lesions. However, the drug also up-regulates the expression of COX-2, which has been suggested to promote the progression of endometriosis. Accordingly, in the present study we analysed whether a combination therapy with telmisartan and a COX-2 inhibitor may be more effective in the treatment of endometriotic lesions than the application of telmisartan alone.

EXPERIMENTAL APPROACH

Endometriotic lesions were induced in the peritoneal cavity of C57BL/6 mice, which were treated daily with an i.p. injection of telmisartan (10 mg·kg^-1 ), parecoxib (5 mg·kg^-1 ), a combination of telmisartan and parecoxib or vehicle. Therapeutic effects on lesion survival, growth, vascularization, innervation and protein expression were studied over 4 weeks by high-resolution ultrasound imaging as well as immunohistochemical and Western blot analyses.

KEY RESULTS

Telmisartan-treated lesions exhibited a significantly reduced lesion volume when compared with vehicle-treated controls and parecoxib-treated lesions. This inhibitory effect of telmisartan was even more pronounced when it was used in combination with parecoxib. The combination therapy resulted in a reduced microvessel density as well as lower numbers of proliferating Ki67-positive cells and higher numbers of apoptotic cleaved caspase-3-positive stromal cells within the lesions. This was associated with a lower expression of COX-2, MMP-9 and p-Akt/Akt when compared with controls. The application of the two drugs further inhibited the ingrowth of nerve fibres into the lesions.

CONCLUSIONS AND IMPLICATIONS

Combination therapy with telmisartan and a COX-2 inhibitor represents a novel, effective pharmacological strategy for the treatment of endometriosis.

Proangiogenic features in chronic pelvic pain caused by adenomyosis

AIM

The study of peculiarities of expression of vascular endothelial growth factor (VEGF) in the tissues of the endometrium and myometrium in patients with adenomyosis, associated with chronic pelvic pain syndrome.

MATERIALS AND METHODS

Uterus macro-preparations obtained after hysterectomy in 60 patients with pelvic pain on a background of diffuse adenomyosis II-III degree were used for morphological examination, and macro-preparations received from 30 women with adenomyosis without pain syndrome. The diagnosis of adenomyosis was confirmed by sonography and magnetic resonance imaging. The expression of VEGF in tissues of the endometrium and myometrium was determined using the immune-histochemical method. The significance of differences of the compared parameters was determined using the criterion of Wilcoxon and Mann-Whitney. The differences were considered statistically significant when p < 0.05.

RESULTS

It was found that a higher expression of VEGF is characteristic for patients with pelvic pain associated with adenomyosis, compared to women with adenomyosis and abnormal uterine bleeding, both in epithelial cells of ectopic endometrium (14.7 ± 1.6% against 10.7 ± 1.6%, p < 0.01), and in smooth myocytes of the myometrium (12.6 ± 1.4% against 9.6 ± 1.2%, p < 0.01) and in the stromal cells of the myometrium (10.1 ± 1.9% versus 7.4 ± 1.8%, p < 0.01).

CONCLUSIONS

An increased expression of VEGF in the tissues of the uterus is one of the most important pathogenetic mechanisms of algogenesis with adenomyosis, associated syndrome of chronic pelvic pain, compared to the silent form of the disease.

Life is 3D: Boosting Spheroid Function for Tissue Engineering

Spheroids provide a 3D environment with intensive cell-cell contacts. As a result of their excellent regenerative properties and rapid progress in their high-throughput production, spheroids are increasingly suggested as building blocks for tissue engineering. In this review, we focus on innovative biotechnological approaches that increase the quality of spheroids for this specific type of application. These include in particular the fabrication of coculture spheroids, mimicking the complex morphology and physiological tasks of natural tissues. In vitro preconditioning under different culture conditions and incorporation of biomaterials improve the function of spheroids and their directed fusion into macrotissues of desired shapes. The continuous development of these sophisticated approaches may markedly contribute to a broad implementation of spheroid-based tissue engineering in future regenerative medicine.

Comprehensive study of angiogenic factors in women with endometriosis compared to women without endometriosis

OBJECTIVE

Endometriosis is a benign gynaecological disease, affecting women during their reproductive years. Angiogenesis represents a crucial step in the pathogenesis of endometriosis, because endometriotic lesions require neovascularization. In this study several angiogenesis-related genes have been studied in the context of endometriosis. Some of the analyzed angiogenic factors as well as their interactions were studied the first time regarding a possible association with endometriosis.

STUDY DESIGN

This case-control study consisted of 205 biopsies of 114 patients comprising 61 endometriosis patients and 53 control patients. Among them in 29 cases paired samples were obtained. VEGFA, VEGFR2, HIF1A, HGF, NRP1, PDGFB, FGF18, TNFα, TGFB2, EPHB4, EPO and ANG mRNA expression was analyzed by qRT-PCR in ectopic tissue samples, in eutopic endometrium of women with and without endometriosis, and in unaffected peritoneum of women with and without endometriosis.

RESULTS

VEGFR2, HIF1A, HGF, PDGFB, NRP1 and EPHB4 are overexpressed in ectopic lesions compared to eutopic tissues. VEGFR2, HGF, PDGFB, NRP1, and EPHB4 showed highest mRNA levels in peritoneal implants, in contrast HIF1A showed the highest expression in ovarian endometriomas. Correlation analyses of angiogenic factors in ectopic lesions revealed the strongest associations between VEGFR2, PDGFB, and EPHB4. We further showed a significant upregulation of VEGFR2, HIF1A and EPHB4 in eutopic endometrium of women with endometriosis compared to that of controls and a trend towards upregulation of HGF. Additionally, a significant downregulation for HIF1A, HGF and EPHB4 was observed in unaffected peritoneal tissues of women with endometriosis compared to controls.

CONCLUSION

We identified new genes (EPHB4 and NRP1) that may contribute to angiogenesis in endometriosis beside known factors (VEGFA, VEGFR2, HIF1A, HGF, and PDGFB). Correlation studies revealed the putative importance of EBHB4 in association with endometriosis. Our analyses support preliminary reports that angiogenic factors seem to be differently expressed in peritoneal implants, ovarian endometriomas and deep infiltrating endometriosis. Our observation that angiogenic factors are differently expressed in the unaffected peritoneum of women with endometriosis compared to women without endometriosis underlines the importance of the peritoneum in the establishment of endometriosis.

Current and emerging vascularization strategies in skin tissue engineering

Vascularization is a key process in skin tissue engineering, determining the biological function of artificial skin implants. Hence, efficient vascularization strategies are a major prerequisite for the safe application of these implants in clinical practice. Current approaches include (i) modification of structural and physicochemical properties of dermal scaffolds, (ii) biological scaffold activation with growth factor-releasing systems or gene vectors, and (iii) generation of prevascularized skin substitutes by seeding scaffolds with vessel-forming cells. These conventional approaches may be further supplemented by emerging strategies, such as transplantation of adipose tissue-derived microvascular fragments, 3D bioprinting and microfluidics, miRNA modulation, cell sheet engineering, and fabrication of photosynthetic scaffolds. The successful translation of these vascularization strategies from bench to bedside may pave the way for a broad clinical implementation of skin tissue engineering.

The gut microbiota: a puppet master in the pathogenesis of endometriosis?

Endometriosis is a frequent gynecologic disease with a complex, multifactorial cause. It is characterized by the cyclic estrogen-driven proliferation and bleeding of endometriotic lesions (ie, ectopic endometrial glands and stroma) outside the uterus. These lesions induce a chronic activation of the innate immune system within the peritoneal cavity that is associated with the release of various inflammatory cytokines and angiogenic growth factors into the peritoneal fluid. This stimulates angiogenesis and the further spread of the lesions and triggers the typical pain that is symptomatic of the disease. Moreover, circulating stem and progenitor cells are recruited into the ectopic endometrial tissue and contribute to its growth and vascularization. In recent years, an increasing number of studies have indicated that the gut microbiota is not only essential for a physiologic gastrointestinal function but acts as a central regulator of a variety of inflammatory and proliferative conditions. Besides, the gut flora affects estrogen metabolism and stem-cell homeostasis. Based on these findings, we hypothesize that the gut microbiota may be involved crucially in the onset and progression of endometriosis. In the future, this novel view of the pathogenesis of endometriosis may be verified by analysis of the development of endometriotic lesions in animal models with a defined composition of the gut microbiota and by investigation of the microbiota of patients with endometriosis with modern next-generation sequencing tools. This could open the door for completely new preventive, diagnostic, and therapeutic approaches for endometriosis.

Cell behaviors and dynamics during angiogenesis

Vascular networks are formed and maintained through a multitude of angiogenic processes, such as sprouting, anastomosis and pruning. Only recently has it become possible to study the behavior of the endothelial cells that contribute to these networks at a single-cell level in vivo. This Review summarizes what is known about endothelial cell behavior during developmental angiogenesis, focusing on the morphogenetic changes that these cells undergo.

Estrogen Stimulates Homing of Endothelial Progenitor Cells to Endometriotic Lesions

The incorporation of endothelial progenitor cells (EPCs) into microvessels contributes to the vascularization of endometriotic lesions. Herein, we analyzed whether this vasculogenic process is regulated by estrogen. Estrogen- and vehicle-treated human EPCs were analyzed for migration and tube formation. Endometriotic lesions were induced in irradiated FVB/N mice, which were reconstituted with bone marrow from FVB/N-TgN (Tie2/green fluorescent protein) 287 Sato mice. The animals were treated with 100 μg/kg β-estradiol 17-valerate or vehicle (control) over 7 and 28 days. Lesion growth, cyst formation, homing of green fluorescent protein(+)/Tie2(+) EPCs, vascularization, cell proliferation, and apoptosis were analyzed by high-resolution ultrasonography, caliper measurements, histology, and immunohistochemistry. Numbers of blood circulating EPCs were assessed by flow cytometry. In vitro, estrogen-treated EPCs exhibited a higher migratory and tube-forming capacity when compared with controls. In vivo, numbers of circulating EPCs were not affected by estrogen. However, estrogen significantly increased the number of EPCs incorporated into the lesions' microvasculature, resulting in an improved early vascularization. Estrogen further stimulated the growth of lesions, which exhibited massively dilated glands with a flattened layer of stroma. This was mainly because of an increased glandular secretory activity, whereas cell proliferation and apoptosis were not markedly affected. These findings indicate that vasculogenesis in endometriotic lesions is dependent on estrogen, which adds a novel hormonally regulated mechanism to the complex pathophysiology of endometriosis.

Role of the protein kinase BRAF in the pathogenesis of endometriosis

OBJECTIVE

Mitogen-activated protein kinases (MAPKs) are involved in the proliferation and survival of endometriotic lesions. Vemurafenib (PLX4032) is a novel protein kinase inhibitor that targets BRAF, a member of the MAPK pathway. The present study tested the in vitro and in vivo effects of PLX4032 on endometriotic cells.

RESEARCH DESIGN AND METHODS

We conducted a laboratory study in a tertiary-care university hospital from January 2013 to September 2013. We enrolled a cohort of 40 patients: 20 with histologically proven endometriosis and 20 unaffected women. A thorough surgical examination of the abdominopelvic cavity was performed on all of the study participants. Ex vivo stromal and epithelial cells were extracted from endometrial and endometriotic biopsies from both sets of patients. Proliferation, apoptosis, pERK/ERK ratio, cell cycle regulation (Cyclin D1 and CDK4) and inflammation (PTGS2) were explored with and without PLX4032 treatment. Human endometriotic lesions were implanted into 40 nude mice that were separated into two groups according to PLX4032 or vehicle treatment, which they received for four weeks, before sacrifice and histological examination.

RESULTS

Treating endometriotic cells with PLX4032 abrogated the phosphorylation of ERK, significantly reducing the pERK/ERK ratio in both epithelial and stromal cells from endometriotic women compared to the controls (p < 0.05). In addition, treatment with PLX4032 significantly decreased proliferation in both stromal and epithelial cells with a concomitant decrease in Cyclin D1/CDK4 complex and PTGS2 levels. Using a murine model of endometriosis, we observed that PLX4032-treated mice displayed a significant decrease in implant volume compared to the initial size; a slight, but non-significant, increase in size was observed in the vehicle-treated mice.

CONCLUSION

Our data suggest that MAPKs and BRAF are involved in the pathogenesis of endometriosis. PLX4032-induced inhibition of BRAF controlled endometriotic growth, both in vitro and in vivo, and could constitute a promising target for the treatment of endometriosis.

The mouse endometrium contains epithelial, endothelial and leucocyte populations expressing the stem cell marker telomerase reverse transcriptase

STUDY HYPOTHESIS

The mouse endometrium harbours stem/progenitor cells that express the stem cell marker mouse telomerase reverse transcriptase (mTert).

STUDY FINDING

We used a mouse carrying a transgenic reporter for mTert promoter activity to identify rare endometrial populations of epithelial and endothelial cells that express mTert.

WHAT IS KNOWN ALREADY

Stem/progenitor cells are hypothesized to be responsible for the remarkable regenerative capacity of the endometrium, but the lack of convenient endometrial stem/progenitor markers in the mouse has hampered investigations into the identity of these cells.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

A mouse containing a green fluorescent protein (GFP) reporter under the control of the telomerase reverse transcriptase promoter (mTert-GFP) was used to identify potential stem/progenitor cells in the endometrium. mTert promoter activity was determined using fluorescence microscopy and flow cytometry to identify GFP(+) cells. GFP(+) cells were examined for epithelial, stromal, endothelial, leucocyte and proliferation markers and bromodeoxyuridine retention to determine their identity. The endometrium of ovariectomized mice was compared to that of intact cycling mice to establish the role of ovarian hormones in maintaining mTert-expressing cells.

MAIN RESULTS AND THE ROLE OF CHANCE

We found that mTert-GFP is expressed by rare luminal and glandular epithelial cells (0.3% of epithelial cells by flow cytometry), rare CD45(-) cells in the stromal compartment (0.028 ± 0.010% of stromal cells by microscopy) and many CD45(+) leucocytes. Ovariectomy resulted in significant decrease of mTert-GFP(+) epithelial cells (P = 0.029 for luminal epithelium; P = 0.034 for glandular epithelium) and a decrease in the percentage of mTert-GFP(+) CD45(+) leucocytes in the stromal compartment (P = 0.015). However, CD45(-) mTert-GFP(+) cells in the stromal compartment were maintained in ovariectomized mice. This population is enriched for cells bearing the endothelial marker CD31 (10.3% of CD90(-) CD45(-) and 97.8% CD90(+) CD45(-) by flow cytometry). CD45(-) mTert-GFP(+) cells also immunostained for the endothelial marker von Willebrand factor. These results suggest that the endometrial epithelium and vasculature are foci of stem/progenitor activity and provide a system to investigate molecular mechanisms involved in endometrial regeneration and repair.

LIMITATIONS, REASONS FOR CAUTION

The stem/progenitor activity of endometrial mTert-GFP(+) cells needs to be experimentally verified.

WIDER IMPLICATIONS OF THE FINDINGS

The identification and characterization of mTert-expressing progenitor cells in the mouse will facilitate the identification of equivalent populations in the human endometrium that are likely to be involved in endometrial function, fertility and disease.

LARGE-SCALE DATA

Not applicable.

STUDY FUNDING AND COMPETING INTERESTS

This study was funded by National Health and Medical Research Council (NHMRC) of Australia grants (1085435, C.E.G., J.A.D.), 1021127 (C.E.G.), NHMRC Senior Research Fellowship (1042298, C.E.G.), the Victorian Infrastructure Support Program, U.S. National Institutes of Health grant R01 DK084056 (D.T.B.) and the Harvard Stem Cell Institute (D.T.B.). The authors have no conflicts of interest to declare.