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A comparison of the angiogenic properties of induced endothelial cells and induced pluripotent stem cell derived endothelial cells in a murine hindlimb ischaemia model
Abstract
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20 A comparison of the angiogenic properties of induced endothelial cells and induced pluripotent stem cell derived endothelial cells in a murine hindlimb ischaemia model Z. Clayton 1,2,∗ , G. Yuen 1,2 , S. Sadeghipour 1 , S. Abraham 3 , J. Wong 4 , J. Hywood 1,2 , J. Cooke 4 , S. Patel 1,2,5 1 Heart
Research Institute, Sydney, Australia 2 University of Sydney, Sydney, Australia 3 Stanford University School of Medicine, Stanford, USA 4 Houston Methodist Research Institute, Houston, USA 5 Royal Prince Alfred Hospital, Sydney, Australia Endothelial cells derived from induced pluripotent stem cells (iPSC-ECs) have been shown to promote angiogenesis in vivo. Recently, an alternative method of generating endothelial cells has been developed, by directly differentiating fibroblasts into endothelial cells (iECs), bypassing the pluripotent intermediate. Here we compared survival, engraftment and pro-angiogenic potential of iECs versus iPSC-ECs in a mouse model of hindlimb ischaemia. Human iPSC-ECs and iECs were transduced with a firefly luciferase and green fluorescent protein reporter for bioluminescence imaging. They exhibited endothelial behavior in vitro, assessed by migration towards VEGF, uptake of acetylated-LDL and tubule formation on matrigel. NODSCID mice (n=7-9) underwent unilateral femoral artery ligation and received either control vehicle or 1x106 iPSCECs or iECs, via intramuscular injection. Recovery of the ischaemic limb was tracked for 14 days. Laser Doppler imaging after femoral artery ligation revealed enhanced blood perfusion recovery in the iEC group vs. control at day 7 (p<0.05), 10 and 14 (p<0.001). IPSC-ECs enhanced recovery vs. control at day 14 (p<0.05). At day 10, perfusion was significantly greater in iEC vs. iPSC-EC treated mice (p<0.01). IPSC-EC and iEC bioluminescent signals decreased over 14 days, but remained above background at all observed timepoints (p<0.0001). Analysis of skeletal muscle demonstrated significantly greater capillary density in the ischaemic limb of mice treated with iECs, vs. control (179±11 vs 125±10 capillaries/image; p<0.05). In conclusion, iECs have striking in vivo pro-angiogenic effects and appear to be more potent than iPSC-ECs. These findings support further development of iECs for therapeutic angiogenesis. http://dx.doi.org/10.1016/j.hlc.2015.06.021
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21 An increase in peak excess pressure accounts for the rise in systolic blood pressure along the aorta O. Narayan 1,∗ , J. Davies 2 , A. Hughes 3 , K. Parker 4 , S. Hope 1 , I. Meredith 1 , J. Cameron 1 1 Monash Cardiovascular Research Centre, MonashHeart and School of Clinical Sciences at Monash Health, Monash University, Melbourne Australia 2 Imperial College Healthcare NHS Trust, International Centre for Vascular Health, London, United Kingdom 3 University College London, Cardiometabolic Phenotyping Group, London, United Kingdom 4 Imperial College London, Department of Bioengineering, Physiological Flow Unit, London, United Kingdom
The mechanisms driving aortic pressure propagation remain incompletely defined. The reservoir-wave approach may more accurately model central aortic pressure generation however its application at differing aortic locations remains unknown. Methods: We analysed invasively acquired aortic pressure waveforms from 40 patients undergoing clinically indicated catheterisation. Waveforms were acquired at the level of the ascending aorta, transverse aortic arch, diaphragm, renal arteries and aortic bifurcation using a solid-state transducer. Reservoir-wave analysis was performed to determine reservoir wave pressures and associated parameters. Repeated measures 1-way-ANOVA with Dunnett’s test for multiple comparisons was used to compare parameters at the 5 aortic sites. Results: Systolic blood pressure increased from the ascending aorta to the bifurcation, whilst diastolic blood pressure remained constant (see Table). The systolic rate constant Ks (relating to characteristic impedance) increased whilst the diastolic rate constant Kd decreased with distal progression. Peak excess pressure increased with distal progression (P<0.001) and accounted for the rise in systolic blood pressure whereas the maximum reservoir pressure decreased. Peak reservoir pressure timing decreased along the aorta (P<0.001). Conclusions: The increase in peak excess pressure along the aorta and the constant time to peak excess pressure suggest that wave transmission is quantitatively more important in determining distal conduit arterial pressures. The decrease in Ks with distal progression is consistent with gradually rising impedance whilst the increase in Kd is suggestive of progressively decreasingly compliance. These findings support previous data suggesting a relatively minor role for wave reflection in determining the amplitude of the aortic pressure waveform.
S122
20 A comparison of the angiogenic properties of induced endothelial cells and induced pluripotent stem cell derived endothelial cells in a murine hindlimb ischaemia model Z. Clayton 1,2,∗ , G. Yuen 1,2 , S. Sadeghipour 1 , S. Abraham 3 , J. Wong 4 , J. Hywood 1,2 , J. Cooke 4 , S. Patel 1,2,5 1 Heart
Research Institute, Sydney, Australia 2 University of Sydney, Sydney, Australia 3 Stanford University School of Medicine, Stanford, USA 4 Houston Methodist Research Institute, Houston, USA 5 Royal Prince Alfred Hospital, Sydney, Australia Endothelial cells derived from induced pluripotent stem cells (iPSC-ECs) have been shown to promote angiogenesis in vivo. Recently, an alternative method of generating endothelial cells has been developed, by directly differentiating fibroblasts into endothelial cells (iECs), bypassing the pluripotent intermediate. Here we compared survival, engraftment and pro-angiogenic potential of iECs versus iPSC-ECs in a mouse model of hindlimb ischaemia. Human iPSC-ECs and iECs were transduced with a firefly luciferase and green fluorescent protein reporter for bioluminescence imaging. They exhibited endothelial behavior in vitro, assessed by migration towards VEGF, uptake of acetylated-LDL and tubule formation on matrigel. NODSCID mice (n=7-9) underwent unilateral femoral artery ligation and received either control vehicle or 1x106 iPSCECs or iECs, via intramuscular injection. Recovery of the ischaemic limb was tracked for 14 days. Laser Doppler imaging after femoral artery ligation revealed enhanced blood perfusion recovery in the iEC group vs. control at day 7 (p<0.05), 10 and 14 (p<0.001). IPSC-ECs enhanced recovery vs. control at day 14 (p<0.05). At day 10, perfusion was significantly greater in iEC vs. iPSC-EC treated mice (p<0.01). IPSC-EC and iEC bioluminescent signals decreased over 14 days, but remained above background at all observed timepoints (p<0.0001). Analysis of skeletal muscle demonstrated significantly greater capillary density in the ischaemic limb of mice treated with iECs, vs. control (179±11 vs 125±10 capillaries/image; p<0.05). In conclusion, iECs have striking in vivo pro-angiogenic effects and appear to be more potent than iPSC-ECs. These findings support further development of iECs for therapeutic angiogenesis. http://dx.doi.org/10.1016/j.hlc.2015.06.021
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21 An increase in peak excess pressure accounts for the rise in systolic blood pressure along the aorta O. Narayan 1,∗ , J. Davies 2 , A. Hughes 3 , K. Parker 4 , S. Hope 1 , I. Meredith 1 , J. Cameron 1 1 Monash Cardiovascular Research Centre, MonashHeart and School of Clinical Sciences at Monash Health, Monash University, Melbourne Australia 2 Imperial College Healthcare NHS Trust, International Centre for Vascular Health, London, United Kingdom 3 University College London, Cardiometabolic Phenotyping Group, London, United Kingdom 4 Imperial College London, Department of Bioengineering, Physiological Flow Unit, London, United Kingdom
The mechanisms driving aortic pressure propagation remain incompletely defined. The reservoir-wave approach may more accurately model central aortic pressure generation however its application at differing aortic locations remains unknown. Methods: We analysed invasively acquired aortic pressure waveforms from 40 patients undergoing clinically indicated catheterisation. Waveforms were acquired at the level of the ascending aorta, transverse aortic arch, diaphragm, renal arteries and aortic bifurcation using a solid-state transducer. Reservoir-wave analysis was performed to determine reservoir wave pressures and associated parameters. Repeated measures 1-way-ANOVA with Dunnett’s test for multiple comparisons was used to compare parameters at the 5 aortic sites. Results: Systolic blood pressure increased from the ascending aorta to the bifurcation, whilst diastolic blood pressure remained constant (see Table). The systolic rate constant Ks (relating to characteristic impedance) increased whilst the diastolic rate constant Kd decreased with distal progression. Peak excess pressure increased with distal progression (P<0.001) and accounted for the rise in systolic blood pressure whereas the maximum reservoir pressure decreased. Peak reservoir pressure timing decreased along the aorta (P<0.001). Conclusions: The increase in peak excess pressure along the aorta and the constant time to peak excess pressure suggest that wave transmission is quantitatively more important in determining distal conduit arterial pressures. The decrease in Ks with distal progression is consistent with gradually rising impedance whilst the increase in Kd is suggestive of progressively decreasingly compliance. These findings support previous data suggesting a relatively minor role for wave reflection in determining the amplitude of the aortic pressure waveform.