- Email: [email protected]
Angiogenesis as a therapeutic target in joint disease
324
Abstracts
ischemic hind limbs is attenuated by HO-1 deficiency both in physiological and streptozotocin (STZ)-induced diabetic conditions and it is related to impaired angiogenesis in HO-1 deficient mice. Moreover, injection of conditioned media from PPCs was efficient in acceleration of blood flow restoration in STZ treated HO-1+/− mice. Noteworthy, the improvement of blood flow recovery was transient and conditioned media from HO-1+/+ PPCs were more potent than media from HO-1−/−. In summary, our data demonstrate HO-1 to be a mediator of proangiogenic properties of bone marrow-derived cells. Injection of conditioned media from PPCs instead of the cells seems to be a good strategy of therapy, however to achieve a prolonged effect it demands optimization. Overexpression of HO-1 in PPCs might be considered as a potential enhancer for therapeutic angiogenesis. doi:10.1016/j.vph.2011.08.054
O.7.2 Late outgrowth endothelial cells are indistinguishable from mature endothelial cells and are not derived from bone marrow Olga Turaa, Elizabeth M. Skinnerb, G. Robin Barclaya, Kay Samuela, Ronald C.J. Gallaghera, Patrick W.F. Hadokeb, Nicholas L. Millsb, David E. Newbyb, Marc Turnera a Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK b Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK E-mail address: [email protected] (O. Tura) Background: A decade of research has sought to identify the origin and phenotype of endothelial progenitor cells (EPC) in order to harness their potential for cardiovascular regeneration. Whilst this concept is clearly important, ambiguity regarding the precise definition of an EPC has hampered progress in this field. Of the populations identified so far, endothelial outgrowth cells (EOC) most closely fulfil the criteria of an EPC, but their origin and circulating precursor have not been identified. Methods and results: Using enrichment and depletion strategies to isolate cell fractions based on the expression of stem cell and endothelial markers, we demonstrate that EOC colony formation is restricted to the CD34+CD133−CD146+ cell fraction. Mature endothelial cells are also defined as CD34+CD133−CD146+ cells. We have further investigated the origin of EOC and compared them to mature human umbilical vein endothelial cells (HUVEC). We report that EOC are identical to mature HUVECs by morphology, surface antigen expression, immunohistochemistry, RT-PCR, proliferation and functional assessments. In vivo data show that early passage EOC and HUVEC implanted in a mouse model of angiogenesis gave substantial blood vessel formation incorporating cells of human origin. Whilst EOC can be readily isolated from umbilical cord and peripheral blood they cannot be isolated from bone marrow or G-CSF mobilised blood raising the possibility that the precursors of EOC are derived from an alternative stem cell niche outside the bone marrow. Indeed, BM-derived outgrowth cells were positive for mesenchymal markers, negative for endothelial markers and they did not form blood vessels in vivo. Conclusion: Our study demonstrates that EOC are similar, if not identical, to mature endothelial cells and raises questions about the true source of these cells. We were not able to generate EOC colonies from bone marrow which contained few of the CD34+CD133−CD146+ cells necessary for colony formation. We therefore conclude that bone marrow is not an important source of EOC. doi:10.1016/j.vph.2011.08.055
SESSION 8 Angiogenesis in diseases L.8.1 Angiogenesis as a therapeutic target in joint disease Ewa Paleolog Kennedy Institute of Rheumatology, Imperial College, London, UK E-mail address: [email protected] Formation of new blood vessels – angiogenesis – is a key to the pathogenesis of a number of diseases, including cancer. The vascular endothelial growth factor (VEGF)/VEGF receptor system is the best characterised regulator of angiogenesis, and has proven to be an excellent therapeutic target in cancer and in certain forms of ocular disease. Crucially, angiogenesis has been documented to underlie rheumatoid arthritis (RA), a chronic systemic inflammatory disease which affects approximately 1–3% of the population in the Western world. RA impacts hugely on patients' quality of life, with up to 30% of RA patients becoming permanently work-disabled within 3 years of diagnosis if left untreated. In RA, the synovial tissue which lines joints and tendons becomes inflamed and increases greatly in mass, due to hyperplasia of the lining cells and infiltration by cells derived from the circulation. Progressive destruction by the invasive synovium of cartilage and bone leads to functional deterioration and profound disability. The most frequent cause of death in RA is cardiovascular disease, and more than 40% of deaths in RA have been reported to be due to ischemic heart disease and heart failure. Despite major advances in the treatment of RA, using biological therapies, particularly treatments targeted at cytokines such as tumour necrosis factor α (TNFα), there is still a significant unmet clinical need in RA, due to non-responders and increased infections following TNFα blockade. The tissue expansion, invasion, expression of cytokines and growth factors and areas of hypoxia which are a feature of RA have resulted in the hypothesis that as well as in cancer, angiogenesis inhibition may be beneficial in RA. We and others have shown that in RA a number of pro- and anti-angiogenic factors are expressed, including VEGF. Furthermore, as is the case in cancer, hypoxia is a feature of RA, and that the hypoxia/hypoxia-inducible factor (HIF) pathway and HIF target genes, particularly VEGF, contribute to RA severity. In animal models of disease, therapies aimed at inhibiting angiogenesis, such as inhibitors of VEGF, have shown remarkable efficacy in animal models of arthritis, reducing disease severity and synovial angiogenesis. More recently, we have shown that blockade of other growth factors involved in angiogenesis, such as epidermal growth factor (EGF), synergises with TNFα inhibition to deactivate vascular endothelium in vivo and reduce arthritis severity. Therefore, inhibitors of angiogenesis and the HIF pathway already in use in cancer or in clinical trials are also potential candidates for therapy in RA. In the future, angiogenesis inhibitors may prove to be beneficial in RA, in combination with existing modalities such as TNFα inhibition. doi:10.1016/j.vph.2011.08.056
L.8.2 From test-tube to therapy in ten years — Can VEGF and heme oxygenases solve preeclampsia? Asif Ahmed BHF Centre for Cardiovascular Sciences, Queen's Medical Research Institute, College of Medicine and Veterinary Medicine, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK E-mail address: [email protected]
Abstracts
ischemic hind limbs is attenuated by HO-1 deficiency both in physiological and streptozotocin (STZ)-induced diabetic conditions and it is related to impaired angiogenesis in HO-1 deficient mice. Moreover, injection of conditioned media from PPCs was efficient in acceleration of blood flow restoration in STZ treated HO-1+/− mice. Noteworthy, the improvement of blood flow recovery was transient and conditioned media from HO-1+/+ PPCs were more potent than media from HO-1−/−. In summary, our data demonstrate HO-1 to be a mediator of proangiogenic properties of bone marrow-derived cells. Injection of conditioned media from PPCs instead of the cells seems to be a good strategy of therapy, however to achieve a prolonged effect it demands optimization. Overexpression of HO-1 in PPCs might be considered as a potential enhancer for therapeutic angiogenesis. doi:10.1016/j.vph.2011.08.054
O.7.2 Late outgrowth endothelial cells are indistinguishable from mature endothelial cells and are not derived from bone marrow Olga Turaa, Elizabeth M. Skinnerb, G. Robin Barclaya, Kay Samuela, Ronald C.J. Gallaghera, Patrick W.F. Hadokeb, Nicholas L. Millsb, David E. Newbyb, Marc Turnera a Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK b Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK E-mail address: [email protected] (O. Tura) Background: A decade of research has sought to identify the origin and phenotype of endothelial progenitor cells (EPC) in order to harness their potential for cardiovascular regeneration. Whilst this concept is clearly important, ambiguity regarding the precise definition of an EPC has hampered progress in this field. Of the populations identified so far, endothelial outgrowth cells (EOC) most closely fulfil the criteria of an EPC, but their origin and circulating precursor have not been identified. Methods and results: Using enrichment and depletion strategies to isolate cell fractions based on the expression of stem cell and endothelial markers, we demonstrate that EOC colony formation is restricted to the CD34+CD133−CD146+ cell fraction. Mature endothelial cells are also defined as CD34+CD133−CD146+ cells. We have further investigated the origin of EOC and compared them to mature human umbilical vein endothelial cells (HUVEC). We report that EOC are identical to mature HUVECs by morphology, surface antigen expression, immunohistochemistry, RT-PCR, proliferation and functional assessments. In vivo data show that early passage EOC and HUVEC implanted in a mouse model of angiogenesis gave substantial blood vessel formation incorporating cells of human origin. Whilst EOC can be readily isolated from umbilical cord and peripheral blood they cannot be isolated from bone marrow or G-CSF mobilised blood raising the possibility that the precursors of EOC are derived from an alternative stem cell niche outside the bone marrow. Indeed, BM-derived outgrowth cells were positive for mesenchymal markers, negative for endothelial markers and they did not form blood vessels in vivo. Conclusion: Our study demonstrates that EOC are similar, if not identical, to mature endothelial cells and raises questions about the true source of these cells. We were not able to generate EOC colonies from bone marrow which contained few of the CD34+CD133−CD146+ cells necessary for colony formation. We therefore conclude that bone marrow is not an important source of EOC. doi:10.1016/j.vph.2011.08.055
SESSION 8 Angiogenesis in diseases L.8.1 Angiogenesis as a therapeutic target in joint disease Ewa Paleolog Kennedy Institute of Rheumatology, Imperial College, London, UK E-mail address: [email protected] Formation of new blood vessels – angiogenesis – is a key to the pathogenesis of a number of diseases, including cancer. The vascular endothelial growth factor (VEGF)/VEGF receptor system is the best characterised regulator of angiogenesis, and has proven to be an excellent therapeutic target in cancer and in certain forms of ocular disease. Crucially, angiogenesis has been documented to underlie rheumatoid arthritis (RA), a chronic systemic inflammatory disease which affects approximately 1–3% of the population in the Western world. RA impacts hugely on patients' quality of life, with up to 30% of RA patients becoming permanently work-disabled within 3 years of diagnosis if left untreated. In RA, the synovial tissue which lines joints and tendons becomes inflamed and increases greatly in mass, due to hyperplasia of the lining cells and infiltration by cells derived from the circulation. Progressive destruction by the invasive synovium of cartilage and bone leads to functional deterioration and profound disability. The most frequent cause of death in RA is cardiovascular disease, and more than 40% of deaths in RA have been reported to be due to ischemic heart disease and heart failure. Despite major advances in the treatment of RA, using biological therapies, particularly treatments targeted at cytokines such as tumour necrosis factor α (TNFα), there is still a significant unmet clinical need in RA, due to non-responders and increased infections following TNFα blockade. The tissue expansion, invasion, expression of cytokines and growth factors and areas of hypoxia which are a feature of RA have resulted in the hypothesis that as well as in cancer, angiogenesis inhibition may be beneficial in RA. We and others have shown that in RA a number of pro- and anti-angiogenic factors are expressed, including VEGF. Furthermore, as is the case in cancer, hypoxia is a feature of RA, and that the hypoxia/hypoxia-inducible factor (HIF) pathway and HIF target genes, particularly VEGF, contribute to RA severity. In animal models of disease, therapies aimed at inhibiting angiogenesis, such as inhibitors of VEGF, have shown remarkable efficacy in animal models of arthritis, reducing disease severity and synovial angiogenesis. More recently, we have shown that blockade of other growth factors involved in angiogenesis, such as epidermal growth factor (EGF), synergises with TNFα inhibition to deactivate vascular endothelium in vivo and reduce arthritis severity. Therefore, inhibitors of angiogenesis and the HIF pathway already in use in cancer or in clinical trials are also potential candidates for therapy in RA. In the future, angiogenesis inhibitors may prove to be beneficial in RA, in combination with existing modalities such as TNFα inhibition. doi:10.1016/j.vph.2011.08.056
L.8.2 From test-tube to therapy in ten years — Can VEGF and heme oxygenases solve preeclampsia? Asif Ahmed BHF Centre for Cardiovascular Sciences, Queen's Medical Research Institute, College of Medicine and Veterinary Medicine, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK E-mail address: [email protected]