The Experts below are selected from a list of 150 Experts worldwide ranked by ideXlab platform

M Verstreken - One of the best experts on this subject based on the ideXlab platform.

  • Accelerated Neointima Formation After Vascular Injury in Mice With Stromelysin-3 (MMP-11) Gene Inactivation
    2016
    Co-Authors: Roger H Lijnen, M Verstreken, I Vanlinthout, Berthe Van Hoef, Marie-christine Rio
    Abstract:

    Abstract—The hypothesis that stromelysin-3 (MMP-11), a unique member of the matrix metalloproteinase (MMP) family, plays a role in neointima formation was tested with the use of a vascular Injury model in wild-type (MMP-111/1) and MMP-11–deficient (MMP-112/2) mice. Neointima formation 2 to 3 weeks after Electric Injury of the femoral artery wa

  • accelerated neointima formation after vascular Injury in mice with stromelysin 3 mmp 11 gene inactivation
    Arteriosclerosis Thrombosis and Vascular Biology, 1999
    Co-Authors: Roger H Lijnen, Berthe Van Hoef, I Vanlinthout, M Verstreken
    Abstract:

    Abstract —The hypothesis that stromelysin-3 (MMP-11), a unique member of the matrix metalloproteinase (MMP) family, plays a role in neointima formation was tested with the use of a vascular Injury model in wild-type (MMP-11+/+) and MMP-11–deficient (MMP-11−/−) mice. Neointima formation 2 to 3 weeks after Electric Injury of the femoral artery was significantly enhanced in MMP-11−/− as compared with MMP-11+/+ mice, in both mice of a pure 129SV genetic background (0.014 versus 0.0010 mm2 at 2 weeks, P <0.001) and those of a 50/50 mixed 129SV/BL6 background (0.030 versus 0.013 mm2 at 3 weeks, P <0.05). The medial areas were comparable, resulting in intima/media ratios that were significantly increased in MMP-11−/− as compared with MMP-11+/+ arteries, in mice of both the 129SV (1.0 versus 0.18, P <0.001) and mixed (1.5 versus 0.70, P <0.05) backgrounds. Nuclear cell counts in cross-sectional areas of the intima of the injured region were higher in arteries from MMP-11−/− mice than in those from MMP-11+/+ mice (210 versus 48, P <0.001, in pure 129SV mice and 290 versus 150, P <0.01, in mice of the mixed genetic background). Immunocytochemical analysis revealed that α-actin–positive and CD45-positive cells were more abundant in intimal sections of MMP-11−/− mice. Degradation of the internal elastic lamina was more extensive in arteries of MMP-11−/− mice than in those of MMP-11+/+ mice (39% versus 6.8% at 3 weeks, P <0.005). The mechanisms by which MMP-11 could impair elastin degradation and cellular migration in this model remain, however, unknown.

D Collen - One of the best experts on this subject based on the ideXlab platform.

  • α2 antiplasmin gene deficiency in mice does not affect neointima formation after vascular Injury
    Arteriosclerosis Thrombosis and Vascular Biology, 2000
    Co-Authors: H R Lijnen, Berthe Van Hoef, Mieke Dewerchin, D Collen
    Abstract:

    Abstract —The hypothesis that α2-antiplasmin (α2-AP), the main physiological plasmin inhibitor, plays a role in neointima formation was tested with use of a vascular Injury model in wild-type (α2-AP+/+) and α2-AP–deficient (α2-AP−/−) mice. The neointimal and medial areas were similar 1 to 3 weeks after Electric Injury of the femoral artery in α2-AP+/+ and α2-AP−/− mice, resulting in comparable intima/media ratios (eg, 0.43±0.12 and 0.42±0.11 2 weeks after Injury). Nuclear cell counts in cross-sectional areas of the intima of the injured region were also comparable in arteries from α2-AP+/+ and α2-AP−/− mice (78±19 and 69±8). Fibrin deposition was not significantly different in arteries of both genotypes 1 day after Injury, and no mural thrombosis was detected 1 week after Injury. Fibrinolytic activity in femoral arterial sections, as monitored by fibrin zymography, was higher in α2-AP−/− mice 1 week after Injury ( P <0.001) but was comparable in both genotypes 2 and 3 weeks after Injury. Staining for elastin did not reveal significant degradation of the internal elastica lamina in either genotype. Immunocytochemical analysis revealed a comparable distribution pattern of α-actin–positive smooth muscle cells in both genotypes. These findings indicate that the endogenous fibrinolytic system of α2-AP+/+ mice is capable of preventing fibrin deposition after vascular Injury and suggest that α2-AP does not play a major role in smooth muscle cell migration and neointima formation in vivo.

  • stromelysin 1 mmp 3 independent gelatinase expression and activation in mice
    Blood, 1998
    Co-Authors: H R Lijnen, Berthe Van Hoef, J Silence, D Collen
    Abstract:

    A potential physiological role of stromelysin-1 (MMP-3) in the expression or activation of gelatinase A (MMP-2) or gelatinase B (MMP-9) in the wall of injured arteries was studied with the use of homozygous MMP-3–deficient (MMP-3−/−) mice. One week after perivascular Electric Injury of the carotid or femoral artery in wild-type (MMP-3+/+) or MMP-3−/− mice, 70 kD and 65 kD proMMP-2 levels were enhanced by twofold to fourfold, with corresponding increases of 20- to 40-fold for active 61 kD and 58 kD MMP-2, and of 10- to 80-fold for 94 kD proMMP-9. Active MMP-2 species represented approximately one third of the total MMP-2 concentration for both MMP-3+/+ and MMP-3−/− mice. Active 83 kD MMP-9 was not detected in noninjured carotid or femoral arteries, whereas one week after Injury its contribution to the total MMP-9 level was 11% to 18% for MMP-3+/+ and MMP-3−/− mice. Immunostaining of arterial sections confirmed enhanced expression of both MMP-2 and MMP-9 after vascular Injury. Double immunostaining showed colocalization of MMP-9 with macrophages in the adventitia, whereas MMP-2 was also detected mainly in the adventitia but failed to colocalize with smooth muscle cells. Cell culture experiments confirmed comparable ratios of active versus latent MMP-2 in skin fibroblasts and smooth muscle cells derived from MMP-3+/+ and MMP-3−/− mice. Addition of plasmin(ogen) did not significantly affect activation of proMMP-2. In MMP-3+/+ and MMP-3−/− macrophages, comparable levels of 94 kD proMMP-9 were detected, and plasmin(ogen)-mediated conversion to 83 kD MMP-9 was obtained in both genotypes. These data thus indicate that proMMP-2 activation may occur via a plasmin- and MMP-3–independent mechanism, whereas plasmin can directly activate proMMP-9 via a MMP-3–independent mechanism.

  • vascular wound healing and neointima formation induced by perivascular Electric Injury in mice
    American Journal of Pathology, 1997
    Co-Authors: Peter Carmeliet, Lieve Moons, J M Stassen, M De Mol, Ann Bouche, J J Van Den Oord, M Kockx, D Collen
    Abstract:

    Vascular interventions for atherothrombotic disease frequently induce neointima formation, which can contribute to restenosis of blood vessels. As the molecular mechanisms of this process remain largely unknown, quantitative models of arterial Injury in transgenic animals may be useful to study this process at the genetic level. Here, an Injury model is proposed in which surgically exposed femoral arteries in mice were injured perivascularly via a single delivery of an Electric current. Transmission electron microscopy, light microscopy, and immunohistochemistry revealed that Electric Injury destroyed all medial smooth muscle cells, denuded the injured segment of intact endothelium, and transiently induced platelet-rich mural thrombosis. A vascular wound-healing response resulted that was characterized by degradation of the mural thrombus, transient infiltration of the vessel wall by inflammatory cells, and progressive removal of the necrotic debris. Topographic analysis revealed repopulation of the media and accumulation in the neointima of smooth muscle cells originating from the uninjured borders and progressing into the necrotic center. Within 3 weeks after Injury, a neointima of 0.026 +/- 0.003 mm2 (n = 7 arteries) was formed that contained a maximum of 12 +/- 1 layers of smooth muscle alpha-actin-immunoreactive cells. Evans blue staining in five Electrically injured arteries revealed a denuded distance of 2.8 +/- 0.2 mm immediately after Injury, which became progressively re-endothelialized from the uninjured borders to 2.2 +/- 0.08 mm (P = 0.013 vs freshly injured by analysis of variance), 0.8 +/- 0.22 mm (P < 0.001), and 0.005 +/- 0.003 mm (P < 0.001) within 2, 7, and 14 days after Injury, respectively. Analysis of 5'-bromo-2'-deoxyuridine incorporation revealed that a maximum of 35 +/- 10% endothelial cells proliferated within 2 days after Injury and that in the media and neointima, a maximum of, respectively, 12 +/- 2% and 18 +/- 3% smooth muscle cells proliferated within 2 weeks after Injury. Thus, Electric Injury of arteries provides a model of vascular wound healing with arterial neointima formation and re-endothelialization that may be useful for the genetic analysis of its molecular mechanisms in transgenic mice.

Peter Carmeliet - One of the best experts on this subject based on the ideXlab platform.

  • receptor independent role of urokinase type plasminogen activator in pericellular plasmin and matrix metalloproteinase proteolysis during vascular wound healing in mice
    Journal of Cell Biology, 1998
    Co-Authors: Peter Carmeliet, Florea Lupu, Lieve Moons, Mieke Dewerchin, Steven A Rosenberg, Jeanmarc Herbert, Desire Collen
    Abstract:

    It has been proposed that the urokinase receptor (u-PAR) is essential for the various biological roles of urokinase-type plasminogen activator (u-PA) in vivo, and that smooth muscle cells require u-PA for migration during arterial neointima formation. The present study was undertaken to evaluate the role of u-PAR during this process in mice with targeted disruption of the u-PAR gene (u-PAR−/−). Surprisingly, u-PAR deficiency did not affect arterial neointima formation, neointimal cell accumulation, or migration of smooth muscle cells. Indeed, topographic analysis of arterial wound healing after Electric Injury revealed that u-PAR−/− smooth muscle cells, originating from the uninjured borders, migrated over a similar distance and at a similar rate into the necrotic center of the wound as wild-type (u-PAR+/+) smooth muscle cells. In addition, u-PAR deficiency did not impair migration of wounded cultured smooth muscle cells in vitro. There were no genotypic differences in reendothelialization of the vascular wound. The minimal role of u-PAR in smooth muscle cell migration was not because of absent expression, since wild-type smooth muscle cells expressed u-PAR mRNA and functional receptor in vitro and in vivo. Pericellular plasmin proteolysis, evaluated by degradation of 125I-labeled fibrin and activation of zymogen matrix metalloproteinases, was similar for u-PAR−/− and u-PAR+/+ cells. Immunoelectron microscopy of injured arteries in vivo revealed that u-PA was bound on the cell surface of u-PAR+/+ cells, whereas it was present in the pericellular space around u-PAR−/− cells. Taken together, these results suggest that binding of u-PA to u-PAR is not required to provide sufficient pericellular u-PA–mediated plasmin proteolysis to allow cellular migration into a vascular wound.

  • inhibitory role of plasminogen activator inhibitor 1 in arterial wound healing and neointima formation a gene targeting and gene transfer study in mice
    Circulation, 1997
    Co-Authors: Peter Carmeliet, Florea Lupu, Lieve Moons, Roger Lijnen, Stefaan Janssens, Desire Collen, Robert D Gerard
    Abstract:

    Background Plasminogen-deficient mice display impaired vascular wound healing and reduced arterial neointima formation after arterial Injury, suggesting that inhibition of plasmin generation might reduce arterial neointima formation. Therefore, we studied the consequences of plasminogen activator inhibitor-1 (PAI-1) gene inactivation and adenoviral PAI-1 gene transfer on arterial neointima formation. Methods and Results Neointima formation was evaluated in PAI-1-deficient (PAI-1(-/-)) mice with perivascular Electric or transluminal mechanical Injury. PAI-1 deficiency improved vascular wound healing in both models: the cross-sectional neointimal area was 0.001+/-0.001 mm(2) in PAI-1(+/+) and 0.016+/-0.008 mm(2) in PAI-1(-/-) mice within 1 week after Electric Injury (P<.02) and 0.055+/-0.008 mm(2) in PAI-1(+/+) and 0.126+/-0.006 mm(2) in PAI-1(-/-) mice within 3 weeks after mechanical Injury (P<.001). Proliferation of smooth muscle cells was not affected by PAI-1 deficiency. Topographic analysis of arterial wound healing after Electric Injury revealed that PAI-1(-/-) smooth muscle cells, originating from the uninjured borders, more rapidly migrated into the necrotic center of the arterial wound than wild-type smooth muscle cells. On the basis of immunostaining, PAI-1 expression was markedly upregulated during vascular wound healing. There were no genotypic differences in reendothelialization of the vascular wound. When PAI-1(-/-) mice were intravenously injected with replication-defective adenovirus expressing human PAI-1 (AdCMVPAI-1), plasma PAI-1 antigen levels increased in a dose-dependent fashion up to to 61+/-8 mu g/mL with 2x10(9) plaque-forming units (pfu) virus. Luminal stenosis was 35+/-13% in control AdRR5-treated (2x10(9) pfu) and suppressed to 5+/-5% in AdCMVPAI-1-treated (6x10(8) pfu) PAI-1(-/-) mice (P<.002). Conclusions By affecting cellular migration, PAI-1 plays an inhibitory role in vascular wound healing and arterial neointima formation after Injury, and adenoviral PAI-1 gene transfer reduces arterial neointima formation in mice.

  • urokinase but not tissue plasminogen activator mediates arterial neointima formation in mice
    Circulation Research, 1997
    Co-Authors: Peter Carmeliet, Florea Lupu, Lieve Moons, Roger Lijnen, J M Herbert, James T B Crawley, Desire Collen
    Abstract:

    Abstract To define the role of the plasminogen activators (PAs) tissue PA (t-PA) and urokinase PA (u-PA) in vascular wound healing, neointima formation and reendothelialization were evaluated after Electric or mechanical arterial Injury in mice with a single or combined deficiency of t-PA (t-PA−/−) and/or u-PA (u-PA−/−). In both models, neointima formation and neointimal cell accumulation were reduced in u-PA−/− and in t-PA−/−/u-PA−/− arteries but not in t-PA−/− arteries. The Electric Injury model was used to characterize the underlying cellular mechanisms. Topographic analysis of vascular wound healing in Electrically injured wild-type and t-PA−/− arteries revealed a similar degree of migration of smooth muscle cells from the noninjured borders into the necrotic center. In contrast, in u-PA−/− and t-PA−/−/u-PA−/− arteries, smooth muscle cells accumulated at the uninjured borders but failed to migrate into the necrotic center. Cultured u-PA−/− but not t-PA−/− smooth muscle cells also failed to migrate in vitro after scrape wounding. Proliferation of smooth muscle cells was not affected by PA deficiency. Reendothelialization after Electric Injury was similar in all genotypes. In situ analysis revealed markedly elevated u-PA zymographic activity, mRNA, and immunoreactivity in smooth muscle cells, endothelial cells, and leukocytes within 1 week after Injury, eg, when cells migrated into the wound. Thus, u-PA plays a significant role in vascular wound healing and arterial neointima formation after Injury, most likely by affecting cellular migration.

  • vascular wound healing and neointima formation induced by perivascular Electric Injury in mice
    American Journal of Pathology, 1997
    Co-Authors: Peter Carmeliet, Lieve Moons, J M Stassen, M De Mol, Ann Bouche, J J Van Den Oord, M Kockx, D Collen
    Abstract:

    Vascular interventions for atherothrombotic disease frequently induce neointima formation, which can contribute to restenosis of blood vessels. As the molecular mechanisms of this process remain largely unknown, quantitative models of arterial Injury in transgenic animals may be useful to study this process at the genetic level. Here, an Injury model is proposed in which surgically exposed femoral arteries in mice were injured perivascularly via a single delivery of an Electric current. Transmission electron microscopy, light microscopy, and immunohistochemistry revealed that Electric Injury destroyed all medial smooth muscle cells, denuded the injured segment of intact endothelium, and transiently induced platelet-rich mural thrombosis. A vascular wound-healing response resulted that was characterized by degradation of the mural thrombus, transient infiltration of the vessel wall by inflammatory cells, and progressive removal of the necrotic debris. Topographic analysis revealed repopulation of the media and accumulation in the neointima of smooth muscle cells originating from the uninjured borders and progressing into the necrotic center. Within 3 weeks after Injury, a neointima of 0.026 +/- 0.003 mm2 (n = 7 arteries) was formed that contained a maximum of 12 +/- 1 layers of smooth muscle alpha-actin-immunoreactive cells. Evans blue staining in five Electrically injured arteries revealed a denuded distance of 2.8 +/- 0.2 mm immediately after Injury, which became progressively re-endothelialized from the uninjured borders to 2.2 +/- 0.08 mm (P = 0.013 vs freshly injured by analysis of variance), 0.8 +/- 0.22 mm (P < 0.001), and 0.005 +/- 0.003 mm (P < 0.001) within 2, 7, and 14 days after Injury, respectively. Analysis of 5'-bromo-2'-deoxyuridine incorporation revealed that a maximum of 35 +/- 10% endothelial cells proliferated within 2 days after Injury and that in the media and neointima, a maximum of, respectively, 12 +/- 2% and 18 +/- 3% smooth muscle cells proliferated within 2 weeks after Injury. Thus, Electric Injury of arteries provides a model of vascular wound healing with arterial neointima formation and re-endothelialization that may be useful for the genetic analysis of its molecular mechanisms in transgenic mice.

Roger H Lijnen - One of the best experts on this subject based on the ideXlab platform.

  • Accelerated Neointima Formation After Vascular Injury in Mice With Stromelysin-3 (MMP-11) Gene Inactivation
    2016
    Co-Authors: Roger H Lijnen, M Verstreken, I Vanlinthout, Berthe Van Hoef, Marie-christine Rio
    Abstract:

    Abstract—The hypothesis that stromelysin-3 (MMP-11), a unique member of the matrix metalloproteinase (MMP) family, plays a role in neointima formation was tested with the use of a vascular Injury model in wild-type (MMP-111/1) and MMP-11–deficient (MMP-112/2) mice. Neointima formation 2 to 3 weeks after Electric Injury of the femoral artery wa

  • accelerated neointima formation after vascular Injury in mice with stromelysin 3 mmp 11 gene inactivation
    Arteriosclerosis Thrombosis and Vascular Biology, 1999
    Co-Authors: Roger H Lijnen, Berthe Van Hoef, I Vanlinthout, M Verstreken
    Abstract:

    Abstract —The hypothesis that stromelysin-3 (MMP-11), a unique member of the matrix metalloproteinase (MMP) family, plays a role in neointima formation was tested with the use of a vascular Injury model in wild-type (MMP-11+/+) and MMP-11–deficient (MMP-11−/−) mice. Neointima formation 2 to 3 weeks after Electric Injury of the femoral artery was significantly enhanced in MMP-11−/− as compared with MMP-11+/+ mice, in both mice of a pure 129SV genetic background (0.014 versus 0.0010 mm2 at 2 weeks, P <0.001) and those of a 50/50 mixed 129SV/BL6 background (0.030 versus 0.013 mm2 at 3 weeks, P <0.05). The medial areas were comparable, resulting in intima/media ratios that were significantly increased in MMP-11−/− as compared with MMP-11+/+ arteries, in mice of both the 129SV (1.0 versus 0.18, P <0.001) and mixed (1.5 versus 0.70, P <0.05) backgrounds. Nuclear cell counts in cross-sectional areas of the intima of the injured region were higher in arteries from MMP-11−/− mice than in those from MMP-11+/+ mice (210 versus 48, P <0.001, in pure 129SV mice and 290 versus 150, P <0.01, in mice of the mixed genetic background). Immunocytochemical analysis revealed that α-actin–positive and CD45-positive cells were more abundant in intimal sections of MMP-11−/− mice. Degradation of the internal elastic lamina was more extensive in arteries of MMP-11−/− mice than in those of MMP-11+/+ mice (39% versus 6.8% at 3 weeks, P <0.005). The mechanisms by which MMP-11 could impair elastin degradation and cellular migration in this model remain, however, unknown.

Lieve Moons - One of the best experts on this subject based on the ideXlab platform.

  • receptor independent role of urokinase type plasminogen activator in pericellular plasmin and matrix metalloproteinase proteolysis during vascular wound healing in mice
    Journal of Cell Biology, 1998
    Co-Authors: Peter Carmeliet, Florea Lupu, Lieve Moons, Mieke Dewerchin, Steven A Rosenberg, Jeanmarc Herbert, Desire Collen
    Abstract:

    It has been proposed that the urokinase receptor (u-PAR) is essential for the various biological roles of urokinase-type plasminogen activator (u-PA) in vivo, and that smooth muscle cells require u-PA for migration during arterial neointima formation. The present study was undertaken to evaluate the role of u-PAR during this process in mice with targeted disruption of the u-PAR gene (u-PAR−/−). Surprisingly, u-PAR deficiency did not affect arterial neointima formation, neointimal cell accumulation, or migration of smooth muscle cells. Indeed, topographic analysis of arterial wound healing after Electric Injury revealed that u-PAR−/− smooth muscle cells, originating from the uninjured borders, migrated over a similar distance and at a similar rate into the necrotic center of the wound as wild-type (u-PAR+/+) smooth muscle cells. In addition, u-PAR deficiency did not impair migration of wounded cultured smooth muscle cells in vitro. There were no genotypic differences in reendothelialization of the vascular wound. The minimal role of u-PAR in smooth muscle cell migration was not because of absent expression, since wild-type smooth muscle cells expressed u-PAR mRNA and functional receptor in vitro and in vivo. Pericellular plasmin proteolysis, evaluated by degradation of 125I-labeled fibrin and activation of zymogen matrix metalloproteinases, was similar for u-PAR−/− and u-PAR+/+ cells. Immunoelectron microscopy of injured arteries in vivo revealed that u-PA was bound on the cell surface of u-PAR+/+ cells, whereas it was present in the pericellular space around u-PAR−/− cells. Taken together, these results suggest that binding of u-PA to u-PAR is not required to provide sufficient pericellular u-PA–mediated plasmin proteolysis to allow cellular migration into a vascular wound.

  • inhibitory role of plasminogen activator inhibitor 1 in arterial wound healing and neointima formation a gene targeting and gene transfer study in mice
    Circulation, 1997
    Co-Authors: Peter Carmeliet, Florea Lupu, Lieve Moons, Roger Lijnen, Stefaan Janssens, Desire Collen, Robert D Gerard
    Abstract:

    Background Plasminogen-deficient mice display impaired vascular wound healing and reduced arterial neointima formation after arterial Injury, suggesting that inhibition of plasmin generation might reduce arterial neointima formation. Therefore, we studied the consequences of plasminogen activator inhibitor-1 (PAI-1) gene inactivation and adenoviral PAI-1 gene transfer on arterial neointima formation. Methods and Results Neointima formation was evaluated in PAI-1-deficient (PAI-1(-/-)) mice with perivascular Electric or transluminal mechanical Injury. PAI-1 deficiency improved vascular wound healing in both models: the cross-sectional neointimal area was 0.001+/-0.001 mm(2) in PAI-1(+/+) and 0.016+/-0.008 mm(2) in PAI-1(-/-) mice within 1 week after Electric Injury (P<.02) and 0.055+/-0.008 mm(2) in PAI-1(+/+) and 0.126+/-0.006 mm(2) in PAI-1(-/-) mice within 3 weeks after mechanical Injury (P<.001). Proliferation of smooth muscle cells was not affected by PAI-1 deficiency. Topographic analysis of arterial wound healing after Electric Injury revealed that PAI-1(-/-) smooth muscle cells, originating from the uninjured borders, more rapidly migrated into the necrotic center of the arterial wound than wild-type smooth muscle cells. On the basis of immunostaining, PAI-1 expression was markedly upregulated during vascular wound healing. There were no genotypic differences in reendothelialization of the vascular wound. When PAI-1(-/-) mice were intravenously injected with replication-defective adenovirus expressing human PAI-1 (AdCMVPAI-1), plasma PAI-1 antigen levels increased in a dose-dependent fashion up to to 61+/-8 mu g/mL with 2x10(9) plaque-forming units (pfu) virus. Luminal stenosis was 35+/-13% in control AdRR5-treated (2x10(9) pfu) and suppressed to 5+/-5% in AdCMVPAI-1-treated (6x10(8) pfu) PAI-1(-/-) mice (P<.002). Conclusions By affecting cellular migration, PAI-1 plays an inhibitory role in vascular wound healing and arterial neointima formation after Injury, and adenoviral PAI-1 gene transfer reduces arterial neointima formation in mice.

  • urokinase but not tissue plasminogen activator mediates arterial neointima formation in mice
    Circulation Research, 1997
    Co-Authors: Peter Carmeliet, Florea Lupu, Lieve Moons, Roger Lijnen, J M Herbert, James T B Crawley, Desire Collen
    Abstract:

    Abstract To define the role of the plasminogen activators (PAs) tissue PA (t-PA) and urokinase PA (u-PA) in vascular wound healing, neointima formation and reendothelialization were evaluated after Electric or mechanical arterial Injury in mice with a single or combined deficiency of t-PA (t-PA−/−) and/or u-PA (u-PA−/−). In both models, neointima formation and neointimal cell accumulation were reduced in u-PA−/− and in t-PA−/−/u-PA−/− arteries but not in t-PA−/− arteries. The Electric Injury model was used to characterize the underlying cellular mechanisms. Topographic analysis of vascular wound healing in Electrically injured wild-type and t-PA−/− arteries revealed a similar degree of migration of smooth muscle cells from the noninjured borders into the necrotic center. In contrast, in u-PA−/− and t-PA−/−/u-PA−/− arteries, smooth muscle cells accumulated at the uninjured borders but failed to migrate into the necrotic center. Cultured u-PA−/− but not t-PA−/− smooth muscle cells also failed to migrate in vitro after scrape wounding. Proliferation of smooth muscle cells was not affected by PA deficiency. Reendothelialization after Electric Injury was similar in all genotypes. In situ analysis revealed markedly elevated u-PA zymographic activity, mRNA, and immunoreactivity in smooth muscle cells, endothelial cells, and leukocytes within 1 week after Injury, eg, when cells migrated into the wound. Thus, u-PA plays a significant role in vascular wound healing and arterial neointima formation after Injury, most likely by affecting cellular migration.

  • vascular wound healing and neointima formation induced by perivascular Electric Injury in mice
    American Journal of Pathology, 1997
    Co-Authors: Peter Carmeliet, Lieve Moons, J M Stassen, M De Mol, Ann Bouche, J J Van Den Oord, M Kockx, D Collen
    Abstract:

    Vascular interventions for atherothrombotic disease frequently induce neointima formation, which can contribute to restenosis of blood vessels. As the molecular mechanisms of this process remain largely unknown, quantitative models of arterial Injury in transgenic animals may be useful to study this process at the genetic level. Here, an Injury model is proposed in which surgically exposed femoral arteries in mice were injured perivascularly via a single delivery of an Electric current. Transmission electron microscopy, light microscopy, and immunohistochemistry revealed that Electric Injury destroyed all medial smooth muscle cells, denuded the injured segment of intact endothelium, and transiently induced platelet-rich mural thrombosis. A vascular wound-healing response resulted that was characterized by degradation of the mural thrombus, transient infiltration of the vessel wall by inflammatory cells, and progressive removal of the necrotic debris. Topographic analysis revealed repopulation of the media and accumulation in the neointima of smooth muscle cells originating from the uninjured borders and progressing into the necrotic center. Within 3 weeks after Injury, a neointima of 0.026 +/- 0.003 mm2 (n = 7 arteries) was formed that contained a maximum of 12 +/- 1 layers of smooth muscle alpha-actin-immunoreactive cells. Evans blue staining in five Electrically injured arteries revealed a denuded distance of 2.8 +/- 0.2 mm immediately after Injury, which became progressively re-endothelialized from the uninjured borders to 2.2 +/- 0.08 mm (P = 0.013 vs freshly injured by analysis of variance), 0.8 +/- 0.22 mm (P < 0.001), and 0.005 +/- 0.003 mm (P < 0.001) within 2, 7, and 14 days after Injury, respectively. Analysis of 5'-bromo-2'-deoxyuridine incorporation revealed that a maximum of 35 +/- 10% endothelial cells proliferated within 2 days after Injury and that in the media and neointima, a maximum of, respectively, 12 +/- 2% and 18 +/- 3% smooth muscle cells proliferated within 2 weeks after Injury. Thus, Electric Injury of arteries provides a model of vascular wound healing with arterial neointima formation and re-endothelialization that may be useful for the genetic analysis of its molecular mechanisms in transgenic mice.