Peter A. W. Rogers

Vascular endothelial growth factor as capillary permeability agent in ovarian hyperstimulation syndrome

We investigated the role of vascular endothelial growth factor (VEGF) in ovarian hyperstimulation syndrome (OHSS). Two similar peaks of permeability activity were seen in OHSS ascites and liver ascites spiked with recombinant human VEGF (rhVEGF); no activity was seen in control liver ascites. Incubation with rhVEGF antiserum decreased activity in the two OHSS peaks by 79% and 65% and the two spiked liver peaks by 49% and 50%. Control serum produced 24% and 27%, and 17% and 0% reductions, respectively. This is evidence that the major capillary permeability agent in OHSS ascites fluid is VEGF.

Recent advances in endometrial angiogenesis research.

This review summarises recent research into the mechanisms and regulation of endometrial angiogenesis. Understanding of when and by what mechanisms angiogenesis occurs during the menstrual cycle is limited, as is knowledge of how it is regulated. Significant endometrial endothelial cell proliferation occurs at all stages of the menstrual cycle in humans, unlike most animal models where a more precise spatial relationship exists between endothelial cell proliferation and circulating levels of oestrogen and progesterone. Recent stereological data has identified vessel elongation as a major endometrial angiogenic mechanism in the mid-late proliferative phase of the cycle. In contrast, the mechanisms that contribute to post-menstrual repair and secretory phase remodelling have not yet been determined. Both oestrogen and progesterone/progestins appear to have paradoxical actions, with recent studies showing that under different circumstances both can promote as well as inhibit endometrial angiogenesis. The relative contribution of direct versus indirect effects of these hormones on the vasculature may help to explain their pro- or anti-angiogenic activities. Recent work has also identified the hormone relaxin as a player in the regulation of endometrial angiogenesis. While vascular endothelial growth factor (VEGF) is fundamental to endometrial angiogenesis, details of how and when different endometrial cell types produce VEGF, and how production and activity is controlled by oestrogen and progesterone, remains to be elucidated. Evidence is emerging that the different splice variants of VEGF play a major role in regulating endometrial angiogenesis at a local level. Intravascular neutrophils containing VEGF have been identified as having a role in stimulating endometrial angiogenesis, although other currently unidentified mechanisms must also exist. Future studies to clarify how endometrial angiogenesis is regulated in the human, as well as in relevant animal models, will be important for a better understanding of diseases such as breakthrough bleeding, menorrhagia, endometriosis and endometrial cancer.

Priorities for Endometriosis Research: Recommendations From an International Consensus Workshop

Endometriosis is an estrogen-dependent disorder where endometrial tissue forms lesions outside the uterus. Endometriosis affects an estimated 10% of women in the reproductive-age group, rising to 30% to 50% in patients with infertility and/or pain, with significant impact on their physical, mental, and social well-being. There is no known cure, and most current medical treatments are not suitable long term due to their side-effect profiles. Endometriosis has an estimated annual cost in the United States of

Localization of vascular endothelial growth factor-D in malignant melanoma suggests a role in tumour angiogenesis

18.8 to

Proprotein convertases promote processing of VEGF-D, a critical step for binding the angiogenic receptor VEGFR-2

22 billion (2002 figures). Although endometriosis was first described more than 100 years ago, current knowledge of its pathogenesis, spontaneous evolution, and the pathophysiology of the related infertility and pelvic pain, remain unclear. A consensus workshop was convened following the 10th World Congress on Endometriosis to establish recommendations for priorities in endometriosis research. One major issue identified as impacting on the capacity to undertake endometriosis research is the need for multidisciplinary expertise. A total of 25 recommendations for research have been developed, grouped under 5 subheadings: (1) diagnosis, (2) classification and prognosis, (3) treatment and outcome, (4) epidemiology, and (5) pathophysiology. Endometriosis research is underfunded relative to other diseases with high health care burdens. This may be due to the practical difficulties of developing competitive research proposals on a complex and poorly understood disease, which affects only women. By producing this consensus international research priorities statement it is the hope of the workshop participants that researchers will be encouraged to develop new interdisciplinary research proposals that will attract increased funding support for work on endometriosis.

Cell proliferation is increased in the endometrium of women with endometriosis

Expression of angiogenic and lymphangiogenic factors by tumours may influence the route of metastatic spread. Vascular endothelial growth factor (VEGF) is a regulator of tumour angiogenesis, but studies of the inhibition of solid tumour growth by neutralizing anti‐VEGF antibodies indicated that other angiogenic factors may be involved. VEGF‐D may be an alternative regulator because like VEGF it is angiogenic and it activates VEGF receptor‐2 (VEGFR‐2), an endothelial cell receptor which is a key signalling molecule in tumour angiogenesis. This study reports the generation of monoclonal antibodies to the receptor‐binding domain of VEGF‐D and the use of these antibodies to localize VEGF‐D in malignant melanoma. VEGF‐D was detected in tumour cells and in vessels adjacent to immunopositive tumour cells, but not in vessels distant from the tumours. These findings are consistent with a model in which VEGF‐D, secreted by tumour cells, activates endothelial cell receptors and thereby contributes to the regulation of tumour angiogenesis and possibly lymphangiogenesis. In addition, VEGF‐D was detected in the vascular smooth muscle, but not the endothelium, of vessels in adult colon. The endothelium of these vessels was negative for VEGFR‐2 and VEGFR‐3. As VEGF receptors can be up‐regulated on endothelium in response to vessel damage and ischaemia, these findings of a specific localization of VEGF‐D in smooth muscle of the blood vessels suggest that VEGF‐D produced by vascular smooth muscle could play a role in vascular repair by stimulating the proliferation of endothelial cells. Copyright

A model to show human uterine receptivity and embryo viability following ovarian stimulation for in vitro fertilization.

Vascular endothelial growth factor (VEGF)‐D is a secreted glycoprotein that induces angio‐genesis and lymphangiogenesis. It consists of a central domain, containing binding sites for VEGF receptor‐2 (VEGFR‐2) and VEGFR‐3, and N‐ and C‐terminal propep‐tides. It is secreted from the cell as homodimers of the full‐length form that can be proteolytically processed to remove the propeptides. It was recently shown, using adenoviral gene delivery, that fully processed VEGF‐D induces angiogenesis in vivo, whereas full‐length VEGF‐D does not. To better understand these observations, we monitored the effect of VEGF‐D processing on receptor binding using a full‐length VEGF‐D mutant that cannot be processed. This mutant binds VEGFR‐2, the receptor signaling for angiogenesis, with ~17, 000‐fold lower affinity than mature VEGF‐D, indicating the importance of processing for interaction with this receptor. Further, we show that members of the proprotein convertase (PC) family of proteases promote VEGF‐D processing, which facilitates the VEGF‐D/VEGFR‐2 interaction. The PCs furin and PC5 promote cleavage of both propeptides, whereas PC7 promotes cleavage of the C‐terminal propeptide only. The finding that PCs promote activation of VEGF‐D and other proteins with roles in cancer such as matrix metalloproteinases, emphasizes the importance of these enzymes as potential regulators of tumor progression and metastasis.—McColl, B. K., Paavonen, K., Karnezis, T., Harris, N. C., Davydova, N., Rothacker, J., Nice, E. C., Harder, K. W., Roufail, S., Hibbs, M. L., Rogers, P. A. W., Alitalo, K., Stacker, S. A., Achen, M. G. Proprotein convertases promote processing of VEGF‐D, a critical step for binding the angiogenic receptor VEGFR‐2. FASEB J. 21, 1088–1098 (2007)

Tumor Cell Response to Synchrotron Microbeam Radiation Therapy Differs Markedly From Cells in Normal Tissues

OBJECTIVE To compare the proliferation of endothelial, epithelial, and stromal cells in the endometrium of women with endometriosis and normal controls. DESIGN Proliferating cells were identified using the monoclonal antibody antiproliferating cell nuclear antigen. A second antibody (CD34) was used to identify endothelial cells (ECs). SETTING University Department of Obstetrics and Gynaecology. PATIENTS Women with laparoscopically proven endometriosis, n = 30. Controls were women with a normal pelvis at laparoscopy performed for tubal sterilization or for infertility due to a male factor, n = 27. MAIN OUTCOME MEASURES Endothelial cells: proliferative index. Epithelial and stromal cells: semi-quantitative immunostaining score. RESULTS The mean EC proliferative index was significantly greater in those with endometriosis compared with controls. This difference was most marked during the proliferative phase of the menstrual cycle. Proliferative phase epithelial and stromal cells demonstrated significantly higher immunostaining scores in endometriosis patients than in controls. CONCLUSIONS We have demonstrated increased numbers of proliferating ECs as well as epithelial and stromal cells in proliferative phase endometrium of women with endometriosis. This suggests that the endometrium of these women might have an enhanced ability to implant and survive in ectopic locations.

Defining Future Directions for Endometriosis Research Workshop Report From the 2011 World Congress of Endometriosis in Montpellier, France

A comparison of the implantation rates following in vitro fertilization (IVF) and embryo transfer (ET) for four major groups indicates differences in the implantation rates as well as in the incidence of multiple implantation. By assuming that the probability of implantation is the product of two variables, uterine receptivity (U) and embryo viability (E), estimates for U and E are derived for each of the four (VF groups using maximum likelihood methods. The UE model is tested using chi-squared goodness-of-fit methods for predicted implantation rates versus observed. The possibility that differences in U values between groups are due to different ovarian stimulation protocols is discussed, as is the values of the UE model in highlighting differences between IVF groups and its importance in predicting multiple pregnancy rates.

VEGF, VEGFR-1, VEGFR-2, microvessel density and endothelial cell proliferation in tumours of the ovary

PURPOSE High-dose synchrotron microbeam radiation therapy (MRT) can be effective at destroying tumors in animal models while causing very little damage to normal tissues. The aim of this study was to investigate the cellular processes behind this observation of potential clinical importance. METHODS AND MATERIALS MRT was performed using a lattice of 25 mum-wide, planar, polychromatic, kilovoltage X-ray microbeams, with 200-microm peak separation. Inoculated EMT-6.5 tumor and normal mouse skin tissues were harvested at defined intervals post-MRT. Immunohistochemical detection of gamma-H2AX allowed precise localization of irradiated cells, which were also assessed for proliferation and apoptosis. RESULTS MRT significantly reduced tumor cell proliferation by 24 h post-irradiation (p = 0.002). An unexpected finding was that within 24 h of MRT, peak and valley irradiated zones were indistinguishable in tumors because of extensive cell migration between the zones. This was not seen in MRT-treated normal skin, which appeared to undergo a coordinated repair response. MRT elicited an increase in median survival times of EMT-6.5 and 67NR tumor-inoculated mice similar to that achieved with conventional radiotherapy, while causing markedly less normal tissue damage. CONCLUSIONS This study provides evidence of a differential response at a cellular level between normal and tumor tissues after synchrotron MRT.