RESUMEN
OBJECTIVES: To evaluate the effect of a polymer-free Biolimus A9-eluting stent [BioFreedom (BF)], compared with that of a biodegradable polymer-based Biolimus A9-eluting stent [BioMatrix Flex (BMF)] and a bare metal stent (BMS) in balloon denuded and radiated hypercholesterolemic rabbit iliac arteries. METHODS: Rabbits were fed with 1% cholesterol diet (n = 14) for 14 days, both iliac arteries were balloon denuded and radiated, and then rabbits were switched to 0.15% cholesterol diet. After 4 weeks, BF (n = 8), BMF (n = 8), and BMS (n = 8) were deployed in denuded and radiated areas. Four weeks later animals were euthanized, arterial segments were processed for morphometry. RESULTS: The neointimal area in vessels implanted with BF stents was significantly less than that seen in vessels implanted with BMS (0.90 mm(2) ± 0.14 vs. 1.29 mm(2) ± 0.23, P <0.01). Percent fibrin and fibrin score were higher with BMF stents compared to BMS (P <0.03 and <0.04) and giant cell number was significantly higher with both BMF and BF stents (P < 0.01 for both). Percent endothelialization was significantly higher and % uncovered struts were lower with BMS compared to either BMF or BF stents (P < 0.05 for both). CONCLUSION: This study demonstrates that compared to BMS, BF stents significantly decreased neointimal hyperplasia.
Asunto(s)
Implantes Absorbibles , Angioplastia de Balón/instrumentación , Aterosclerosis/terapia , Fármacos Cardiovasculares/administración & dosificación , Stents Liberadores de Fármacos , Hipercolesterolemia/complicaciones , Arteria Ilíaca/patología , Metales , Polímeros , Sirolimus/análogos & derivados , Stents , Animales , Aterosclerosis/etiología , Aterosclerosis/metabolismo , Aterosclerosis/patología , Constricción Patológica , Modelos Animales de Enfermedad , Fibrina/metabolismo , Hiperplasia , Arteria Ilíaca/metabolismo , Arteria Ilíaca/efectos de la radiación , Inflamación/patología , Masculino , Neointima , Placa Aterosclerótica , Diseño de Prótesis , Conejos , Sirolimus/administración & dosificación , Factores de TiempoRESUMEN
BACKGROUND: Injection of bone marrow cells (BMC) and endothelial progenitor cells (EPC) or application of stem-cell-mobilizing factors has been associated both with reduction or exacerbation of atherosclerosis and with unstable plaque phenotype. The discrepancies may reflect the cell type, dosing, duration, and route of administration of cells in these studies. The aim of this study was to determine the effects of peripheral-blood-derived endothelial progenitor cells (PBEPC) or unfractionated BMC obtained from inbred siblings on neointimal formation and inflammation in cholesterol-fed, balloon-denuded, and radiated rabbit iliac arteries. METHODS: Rabbits were fed a 1.0% cholesterol diet for 14 days, followed by endothelial denudation in both iliac arteries, and continued on a 0.15% cholesterol diet. On day 42, denuded areas were radiated, and animals were randomized. The first group received PBEPC (n=5), the second group received BMC (n=4), and the third group received heparinized (20 IU) saline (Control; n=3). PBEPC were characterized by flow cytometry. Cells (5x10(6)) or saline was administered twice through the ear vein: the first time at 1 h after radiation and the second time at 2 weeks after radiation. Four weeks after radiation, the animals were sacrificed, and arterial segments were processed for morphometry. RESULTS: Administration of BMC or PBEPC from inbred siblings had no adverse effect. Lumen area (0.93+/-0.53 mm(2)), neointimal area (0.65+/-0.29 mm(2)), percent stenosis (44+/-21), and macrophage score (0.6+/-0.3) in controls were similar to those in cell-treated groups. CONCLUSION: This study demonstrates that, in the current animal model, either PBEPC or BMC failed to affect neointimal formation or inflammation.
Asunto(s)
Aterosclerosis/prevención & control , Trasplante de Médula Ósea , Células Endoteliales/trasplante , Trasplante de Células Madre Hematopoyéticas , Arteria Ilíaca/patología , Inflamación/prevención & control , Túnica Íntima/patología , Angioplastia de Balón/efectos adversos , Animales , Aterosclerosis/etiología , Aterosclerosis/patología , Células Cultivadas , Colesterol/administración & dosificación , Constricción Patológica , Modelos Animales de Enfermedad , Hiperplasia , Arteria Ilíaca/lesiones , Arteria Ilíaca/efectos de la radiación , Inflamación/etiología , Inflamación/patología , Macrófagos/patología , Masculino , Conejos , Túnica Íntima/lesiones , Túnica Íntima/efectos de la radiaciónRESUMEN
BACKGROUND: Platelet-derived peptide and nonpeptide growth factors are known to play pivotal roles in neointimal proliferation. Along with its antiplatelet activity of reducing P-selectin and hs-CRP, clopidogrel has also been shown to have anti-inflammatory properties. The aim of this study is to find out by modulating inflammation if clopidogrel can affect neointima formation in balloon-denuded iliac arteries of hypercholesterolemic rabbits. METHODS AND RESULTS: Rabbits were fed with 1% cholesterol diet with (n = 20) or without (n = 20) clopidogrel (10 mg/kg body weight) for 7 days followed by balloon-denudation of endothelial layer in both the iliac arteries and continued on 0.15% cholesterol diet with or without clopidogrel. Four weeks later, the denuded area in both iliac arteries was radiated (n = 11, cholesterol-only group; n = 9, clopidogrel group) or sham treated (n = 10 from each group). Four weeks after radiation, animals were sacrificed and arterial segments were processed for morphometry. In the sham-treated clopidogrel group, neointimal area, percent stenosis, and macrophage score were 39% (P = 0.01), 32% (P = 0.02), and 50% (P = 0.02) smaller, respectively, when compared to the cholesterol-only group (0.48 +/- 0.18, 32.42 +/- 13.04, and 1.5 +/- 0.83). There were no differences in the radiated group (0.89 +/- 0.32, 50.34 +/- 13.00, and 1.88 +/- 1.27 vs. 0.93 +/- 0.38, 59.41 +/- 11.41, and 2.00 +/- 0.74, respectively). CONCLUSION: This study demonstrates that clopidogrel reduces inflammation and neointimal formation in balloon-denuded iliac arteries of hypercholesterolemic rabbits.
Asunto(s)
Angioplastia Coronaria con Balón , Hipercolesterolemia/fisiopatología , Arteria Ilíaca/efectos de los fármacos , Inflamación/tratamiento farmacológico , Inhibidores de Agregación Plaquetaria/farmacología , Ticlopidina/análogos & derivados , Túnica Íntima/efectos de los fármacos , Animales , Proteína C-Reactiva/efectos de los fármacos , Clopidogrel , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/efectos de la radiación , Hipercolesterolemia/tratamiento farmacológico , Hipercolesterolemia/radioterapia , Arteria Ilíaca/efectos de la radiación , Macrófagos , Masculino , Selectina-P/efectos de los fármacos , Conejos , Ticlopidina/farmacologíaRESUMEN
BACKGROUND: Biocorrodible iron stents carry the potential to overcome limitations, such as chronic inflammation and premature recoil, posed by biodegradable polymer and magnesium alloy stents. This study aimed to test the safety and efficacy of biocorrodible iron stents in porcine coronary arteries. METHODS: Iron stents and cobalt chromium stents were randomly deployed in the coronary arteries of juvenile domestic pigs. Animals were sacrificed at 28 days, and the vessels were fixed and processed for histochemistry. RESULTS: At 28 days, iron stents started to show signs of degradation without evidence of stent particle embolization or thrombosis without traces of excess inflammation, or fibrin deposition. At 28 days, the surface of the iron stent struts was black to brown and the vascular wall adjacent to the iron stent had a brownish tinge. There were no statistically significant differences in any of the measured parameters between segments implanted with iron and cobalt chromium stents. There were also no adverse effects in the persistent areas. CONCLUSION: The current study demonstrates that stents made of biocorrodible iron are safe. In some of the measured parameters, such as intimal thickness, intimal area, and percentage occlusion, there was a trend in favor of the iron stents.
Asunto(s)
Materiales Biocompatibles/efectos adversos , Enfermedad de la Arteria Coronaria/cirugía , Vasos Coronarios/patología , Compuestos de Hierro , Stents , Animales , Cromo , Cobalto , Reestenosis Coronaria/etiología , Trombosis Coronaria/etiología , Fibrina , Inflamación/etiología , Stents/efectos adversos , PorcinosRESUMEN
OBJECTIVE: We aimed to evaluate an effective dosage and safety profile of pimecrolimus as an anti-inflammatory drug for drug-eluting stents. METHODS: In the dose finding study, coronary arteries of 20 domestic swine were randomly implanted with bare metal stents (ProKinetic and Guidant Vision), the ProKinetic stent with polylactic acid (PLLA), and pimecrolimus-eluting stents (32, 75, and 120 microg) over a period of 4 weeks. In addition, pimecrolimus (75 microg) and ProKinetic stents were randomly implanted into six swine over 3 months. In the safety study, the ProKinetic stent, the ProKinetic stent with PLLA, mid- (45 microg) and high-dose pimecrolimus (120 microg), and overlapping mid-dose stents were implanted over a period of 4 weeks. Mid-dose, ProKinetic stent, and ProKinetic stent with PLLA were implanted over a period of 3 months. RESULTS: The dose finding study revealed excellent luminal patency with low percent occlusion (approximately 29% vs. approximately 41%), injury (0.53-0.59 vs. 1.25), and inflammation (0.78-0.97 vs. 1.08) for the pimecrolimus group compared with the vision group. The safety study arm showed similar angiographic results for all tested groups, with a significantly larger minimal lumen diameter for pimecrolimus stents compared to PLLA stents. Except for the high-dose group and overlapping area of the overlapping group, promising morphometric results were found for pimecrolimus compared to bare metal stents. CONCLUSIONS: Present data suggest that pimecrolimus-eluting stents are safe and have a similar healing profile to bare metal stents. They may suppress inflammation, leading to a reduced intimal response and a milder inflammatory reaction in a porcine model.
Asunto(s)
Antiinflamatorios/administración & dosificación , Enfermedad Coronaria/terapia , Vasos Coronarios/efectos de los fármacos , Stents Liberadores de Fármacos , Tacrolimus/análogos & derivados , Cicatrización de Heridas/efectos de los fármacos , Análisis de Varianza , Animales , Angiografía Coronaria , Enfermedad Coronaria/patología , Vasos Coronarios/patología , Modelos Animales de Enfermedad , Distribución Aleatoria , Estadísticas no Paramétricas , Porcinos , Tacrolimus/administración & dosificación , Factores de Tiempo , Túnica Íntima/efectos de los fármacos , Túnica Íntima/patología , Ultrasonografía Intervencional , Grado de Desobstrucción VascularRESUMEN
Heart failure is associated with a high rate of morbidity and mortality. In some patients, current treatment modalities may not be adequate to prevent myocardial remodeling, which leads to exacerbation of the disease. Cell therapy is based on the premise of replacing damaged myocardium with functional tissues. Multiple forms of stem cells, including bone marrow-derived stem cells and skeletal myoblasts, have been investigated using several delivery routes of administration. Different mechanisms have been proposed to explain the beneficial effects of cell-based therapy. These include cell transdifferentiation, cell fusion, and release of paracrine growth factors. The beneficial effects of cell therapy may involve multiple mechanisms. The encouraging results of early clinical cell therapy studies have not been sustained by subsequent robust studies. These findings suggest that many unanswered questions need to be addressed before cell therapy becomes an acceptable adjunctive treatment for heart failure.
Asunto(s)
Infarto del Miocardio/cirugía , Trasplante de Células Madre/métodos , Células Madre/fisiología , Ensayos Clínicos como Asunto , Humanos , Trasplante de Células Madre/tendencias , Células Madre/citologíaRESUMEN
BACKGROUND AND OBJECTIVES: Secreted growth factors and cell-to-cell contact are both required to elicit cellular functions. We tested the hypothesis that bone-marrow-derived growth factors, together with cell-to-cell contact between bone-marrow-derived stem cells and cardiomyocytes or myoblasts, promote the proliferation of cardiomyocytes and myoblasts. METHODS: Human cardiomyocytes or skeletal myoblasts were cultured for 4 days in the presence of low and high concentrations of bone-marrow-derived mononuclear cell conditioned medium (MNC-CM) or marrow stromal cell conditioned medium (MSC-CM). The concentrations of vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), hepatocyte growth factor (HGF), and insulin-like growth factor-1 in their respective conditioned media were assayed by enzyme-linked immunosorbent assay. Stem cells were mixed with cardiomyocytes or skeletal myoblasts at a 1:1 ratio and cultured for 7 days to assess the proliferation of these cells. In parallel experiments, equal numbers of various cell types were cultured alone. RESULTS: The concentrations of VEGF, MCP-1, and HGF increased in MNC-CM and MSC-CM. MNC-CM showed no effect on cardiomyocyte proliferation. A low concentration of MSC-CM increased cardiomyocyte proliferation by 60% (P<.05). Low concentrations of MNC-CM or MSC-CM showed a trend toward an increased proliferation of myoblasts. A high concentration of either conditioned medium showed a toxic effect. In contact coculture, the proliferation of cardiomyocytes and MNC showed no synergistic effect; instead, there was some evidence of inhibition. The proliferation of cardiomyocytes and stromal cells showed an additive effect. Myoblasts in contact coculture with MNC or MSC showed no synergistic effect. CONCLUSION: These in vitro results suggest that paracrine effects may be the mechanism by which stromal cells become beneficial in cardiac therapy. MNC do not induce the proliferation of cardiomyocytes. Stem-cell-secreted growth factors induce the proliferation of myoblasts, which is not influenced by cell-to-cell contact.
Asunto(s)
Células de la Médula Ósea/metabolismo , Mioblastos Esqueléticos/fisiología , Miocitos Cardíacos/fisiología , Células Madre/metabolismo , Análisis de Varianza , Células Cultivadas , Quimiocina CCL2/metabolismo , Ensayo de Inmunoadsorción Enzimática , Factor de Crecimiento de Hepatocito/metabolismo , Humanos , Técnicas In Vitro , Proteína 1 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Mioblastos Esqueléticos/metabolismo , Miocitos Cardíacos/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
OBJECTIVE: We aimed to determine the safety and efficacy of biobasorbable magnesium alloy stents in porcine coronary arteries. Bioabsorbable magnesium stents carry the potential to overcome the limitations posed by permanent metallic stents such as chronic inflammation, late stent thrombosis, prolonged antiplatelet therapy, and artifacts when imaged by multislice-computed tomography or magnetic resonance imaging. METHODS: Magnesium alloy stents or stainless steel stents were randomly deployed in coronary arteries of domestic or minipigs. Domestic pigs were sacrificed at 3 days (n = 2) or 28 days, and minipigs at 3 months. RESULTS: At 3 days, magnesium alloy stents were intact, but started to show signs of degradation by 28 days. There was no evidence of stent particle embolization, thrombosis, excess inflammation, or fibrin deposition. At 28 days and 3 months, neointimal area was significantly less in magnesium alloy stent segments (2.44 +/- 0.88 mm(2) and 1.16 +/- 0.19 mm(2)) as compared with the stainless steel stent segments (5.03 +/- 1.5 mm(2) and 1.72 +/- 0.68 mm(2), P < 0.001 and 0.02). Quantitative coronary analysis indicates that percentage area stenosis and percentage diameter stenosis in magnesium alloy stent segments improved significantly at 3 months as compared to 28 days. Despite decreased neointimal hyperplasia, lumen area of the magnesium alloy stented vessels did not improve significantly. CONCLUSION: Magnesium alloy stents are safe and are associated with less neointima formation; however, reduced neointima did not result in larger lumen.
Asunto(s)
Implantes Absorbibles , Angioplastia Coronaria con Balón/instrumentación , Estenosis Coronaria/terapia , Compuestos de Magnesio , Stents , Animales , Angiografía Coronaria , Reestenosis Coronaria/prevención & control , Estenosis Coronaria/diagnóstico por imagen , Modelos Animales de Enfermedad , Estudios de Seguimiento , Porcinos , Porcinos Enanos , Resultado del Tratamiento , Ultrasonografía IntervencionalRESUMEN
BACKGROUND: Everolimus is an orally active derivative of sirolimus. Oral administration of rapamycin is efficacious in the reduction of neointima formation and clinical restenosis; however, its optimal dose and duration have not been determined. METHODS: New Zealand White rabbits were divided into three groups. The first (low-dose) group received 1.5 mg/kg everolimus 1 day before stenting, followed by 0.75 mg/kg/day everolimus for 28 days. The second (high-dose) group received 6 mg/kg everolimus 1 day before, on the day of, and on the day after stenting, followed by 2 mg/kg/day for 4 days. The third (placebo) group received a matching volume of vehicle similar to that of Group 2. Twenty-eight days after stenting, animals were euthanized and morphometry was performed. RESULTS: In the high-dose group, circulating everolimus levels corresponded with administrated dose levels; by Day 12, no circulating everolimus could be detected. In the low-dose everolimus group, levels remained constant up to 28 days. When compared with placebo, low-dose everolimus was associated with a significant reduction in medial thickness (32%), neointimal area (60%), and percent stent stenosis (33%); however, high-dose everolimus had no significant effect. CONCLUSIONS: In conclusion, oral everolimus suppresses in-stent neointimal growth in rabbit iliac arteries. Four weeks of low-dose everolimus is more effective than 7 days of high-dose everolimus.
Asunto(s)
Oclusión de Injerto Vascular/prevención & control , Arteria Ilíaca/efectos de los fármacos , Inmunosupresores/administración & dosificación , Sirolimus/análogos & derivados , Stents , Túnica Íntima/efectos de los fármacos , Administración Oral , Animales , Implantación de Prótesis Vascular , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Everolimus , Oclusión de Injerto Vascular/sangre , Oclusión de Injerto Vascular/fisiopatología , Arteria Ilíaca/metabolismo , Arteria Ilíaca/patología , Arteria Ilíaca/cirugía , Inmunosupresores/sangre , Masculino , Conejos , Sirolimus/administración & dosificación , Sirolimus/sangre , Factores de Tiempo , Túnica Íntima/metabolismo , Túnica Íntima/patología , Túnica Íntima/cirugía , Túnica Media/efectos de los fármacos , Túnica Media/cirugía , Grado de Desobstrucción Vascular/efectos de los fármacosRESUMEN
The present report contains the final results of a Phase I study that evaluated the feasibility, safety, and potential efficacy of intramyocardial injection of autologous bone marrow (BM) in "no-option" patients with refractory angina and myocardial ischemia. Twenty-seven patients underwent electromechanic mapping-guided transendomyocardial injections (n = 12, 0.2 ml each) of unfractionated autologous BM cells directed to ischemic, noninfarcted myocardial territory. Patients were injected with 28 +/- 27 x 10(6)/ml nucleated cells containing 2.2 +/- 1.4% CD34+ cells. The autologous BM injection procedure was successful in all patients and was associated with no adverse events. At 3 months, the Canadian Cardiovascular Society angina score (3.2 +/- 0.5 vs 2.0 +/- 0.91, p = 0.001) and treadmill exercise duration (418 +/- 136 vs 489 +/- 142 seconds, p = 0.017) had improved significantly. The stress-induced ischemia score within the injected territories (118 segments) had also improved (2.2 +/- 0.8 vs 1.7 +/- 1.1, p < 0.001). At 1 year, the clinical improvement was sustained, although 5 patients had undergone revascularization procedures. The number of total injected nucleated cells (CD45+), progenitor cells (CD34+), and the magnitude of secreted vascular endothelial growth factor and macrophage chemoattractant protein-1 by cultured BM cells failed to predict the clinical response. In conclusion, the 3- and 12-month study results have indicated the safety of catheter-based transendocardial delivery of autologous BM cells in patients with advanced symptomatic ischemic heart disease and may suggest sustained potential efficacy. The cellular and humeral characteristics of autologous BM cells did not predict the clinical response, underscoring the advisability of additional mechanistic exploration.
Asunto(s)
Angina Inestable/terapia , Trasplante de Médula Ósea , Isquemia Miocárdica/terapia , Células de la Médula Ósea/metabolismo , Supervivencia Celular , Quimiocina CCL2/metabolismo , Circulación Coronaria , Estudios de Factibilidad , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Dolor Intratable/fisiopatología , Fragmentos de Péptidos/metabolismo , Trasplante Autólogo , Resultado del Tratamiento , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Peroxisome proliferator-activated receptor (PPAR)-gamma activation suppresses inflammatory response, monocyte recruitment, and vascular cell proliferation. Because inflammation, deregulated growth, and migration of monocytes and vascular smooth muscle cells (VSMC) play important roles in the development of neointima, we tested the effect of pioglitazone, a high-affinity ligand, for PPAR-gamma on neointima formation in the iliac arteries of a balloon-denuded and radiated hypercholesterolemic rabbit. Rabbits were fed a 1.0% cholesterol diet for 7 days followed by denudation of endothelial layer and continued on a 0.15% cholesterol diet. On day 32, animals were divided into 2 groups. One group received a 0.15% cholesterol diet (n = 7) and the other group received a 0.15% cholesterol diet supplemented with 400 mg of pioglitazone per kilogram. On day 35, the balloon-denuded area was radiated. Four weeks after radiation, animals were sacrificed and arterial segments were processed for morphometry and immunohistochemistry. Data analysis showed that the pioglitazone group had smaller neointima (0.85 +/- 0.36 vs. 1.41 +/- 0.56, P < 0.05), with more cells positive for VSMC (23.07 +/- 6.16 vs. 18.33 +/- 5.19, P = 0.04), less for monocytes (16.01 +/- 5.33 vs. 21.29 +/- 4.33, P < 0.05), and fewer cells expressing metalloproteinase (MMP)-1 and MMP-9 (3.69 +/- 0.47 vs. 4.82 +/- 0.93, P < 0.05 and 3.24 +/- 0.71 vs. 4.29 +/- 0.74, P < 0.05, respectively). Pioglitazone reduced neointimal area and modified its composition in a balloon-denuded and radiated hypercholesterolemic rabbit model.
Asunto(s)
Hipercolesterolemia/tratamiento farmacológico , PPAR gamma/agonistas , Tiazolidinedionas/farmacología , Túnica Íntima/efectos de los fármacos , Actinas/análisis , Administración Oral , Animales , Peso Corporal/efectos de los fármacos , Cateterismo , Colesterol en la Dieta/administración & dosificación , Hipercolesterolemia/inducido químicamente , Hipercolesterolemia/metabolismo , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Inmunohistoquímica , Macrófagos/química , Macrófagos/efectos de los fármacos , Masculino , Metaloproteinasa 1 de la Matriz/análisis , Metaloproteinasa 3 de la Matriz/análisis , Metaloproteinasa 9 de la Matriz/análisis , Músculo Liso Vascular/química , Músculo Liso Vascular/patología , Músculo Liso Vascular/ultraestructura , Pioglitazona , Conejos , Tiazolidinedionas/administración & dosificación , Tiazolidinedionas/uso terapéutico , Túnica Íntima/química , Túnica Íntima/patología , Túnica Media/química , Túnica Media/efectos de los fármacos , Túnica Media/patologíaRESUMEN
Here we review PPARgamma function in relation to human adipogenesis, insulin sensitization, lipid metabolism, blood pressure regulation and prothrombotic state to perhaps provide justification for this nuclear receptor remaining a key therapeutic target for the continuing development of agents to treat human metabolic syndrome.
Asunto(s)
Síndrome Metabólico/metabolismo , PPAR gamma/fisiología , Tejido Adiposo/metabolismo , Antiinflamatorios no Esteroideos/farmacología , Humanos , Hiperlipidemias/metabolismo , Hipertensión/metabolismo , Hipoglucemiantes/farmacología , Inflamación/metabolismo , Resistencia a la Insulina/fisiología , Síndrome Metabólico/tratamiento farmacológico , PPAR gamma/efectos de los fármacos , Protrombina/metabolismoRESUMEN
OBJECTIVES: The aim of this research was to test the effects of vascular endothelial growth factor (VEGF)/angiopoietin-1 (Ang-1) on adult hypoperfused tissues. BACKGROUND: Angiopoietin-1 and VEGF act separately and synergistically in vascular development during embryogenesis. However, little is known regarding their relative roles in collateral development after chronic arterial obstruction and tissue ischemia in the adult. METHODS: Central and caudal ear arteries of 32 rabbits were ligated to induce ischemia. At two months, when flow was about 65% of pre-ligation values, we injected intradermally 10(9) plaque-forming unit adenovirus with the following transgenes: Ang-1, VEGF, or a combination of both. Ear perfusion was followed up for four weeks, and vessel leakage was assessed by Evens Blue test. RESULTS: Before injection, flow was 65% of baseline, and endogenous VEGF levels in ischemic tissue were increased. Adenovirus-encoding VEGF gene (Ad.VEGF) at one week caused a visible inflammatory response associated with a 24% flow increase (p = 0.018). Adenovirus-encoding Ang-1 gene (Ad.Ang-1) increased flow 22% (p = 0.004) with no visible inflammation; Ad.VEGF caused three times as much vessel leakage as Ad.Ang-1 (142.5 +/- 38 vs. 49.5 +/- 9.8 ng Evens Blue/mg tissue; p < 0.001). However, at four weeks, compared with baseline, VEGF decreased flow 18% (p = 0.004), whereas Ang-1 increased tissue perfusion 26% (p < 0.001). This effect was abolished when Ad.Ang-1 was injected with soluble VEGF receptor [Ad.Flt(1-3)-Fc], which blocks VEGF-dependent signaling. Exogenous Ang-1 did not increase perfusion in a normally perfused ear, in which endogenous VEGF is not expressed. CONCLUSIONS: Exogenous Ang-1 enhances perfusion in hypoperfused tissues only in the presence of increased levels of endogenous VEGF. Overexpression of VEGF, however, after causing an inflammatory response, does not improve collateral blood flow.
Asunto(s)
Inductores de la Angiogénesis/farmacología , Angiopoyetina 1/farmacología , Endotelio Vascular/efectos de los fármacos , Isquemia/tratamiento farmacológico , Neovascularización Fisiológica/efectos de los fármacos , Factor A de Crecimiento Endotelial Vascular/farmacología , Adenoviridae/genética , Animales , Oído Externo/irrigación sanguínea , Expresión Génica , Terapia Genética , Isquemia/fisiopatología , Masculino , Neovascularización Fisiológica/genética , Conejos , Distribución Aleatoria , Flujo Sanguíneo RegionalRESUMEN
We investigated the effect of contrast media on bone marrow-derived cell viability, growth factor secretion, and myoblast viability. Bone marrow was exposed to contrast media, mononuclear cells were isolated, viability was assessed by Trypan blue exclusion or cultured for 4 weeks, and conditioned medium was assayed for vascular endothelial growth factor (VEGF) and monocyte chemoattractant protein-1 (MCP-1). Skeletal myoblasts viability was assessed after exposing them to contrast media. In separate experiments, bone marrow or bone marrow-derived mononuclear cells were exposed to contrast media, cultured for 40 hr, then assessed for viability. None of the contrast media tested had any effect on bone marrow-derived cell viability. Hypaque or Hexabrix increased myoblasts viability by 8-10%. VEGF and MCP-1 concentrations in the conditioned medium increased in a time-related manner. These findings support the concept that for cell therapy, bone marrow cells or myoblasts may be mixed with contrast media and injected into ischemic myocardium without compromise in viability or function.
Asunto(s)
Células de la Médula Ósea/efectos de los fármacos , Quimiocina CCL2/metabolismo , Medios de Contraste/farmacología , Mioblastos Esqueléticos/efectos de los fármacos , Factor A de Crecimiento Endotelial Vascular/metabolismo , Animales , Células de la Médula Ósea/metabolismo , Bovinos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Porcinos , Factores de TiempoRESUMEN
Cellular proliferation and migration are fundamental processes that contribute to the injury response in major blood vessels. The resultant pathologies are atherosclerosis and restenosis. As we begin to understand the cellular changes associated with vascular injury, it is critical to determine whether the inhibition of growth and movement of cells in the vasculature could serve as a novel therapeutic strategy to prevent atherosclerosis and restenosis.
Asunto(s)
Enfermedad de la Arteria Coronaria/fisiopatología , Reestenosis Coronaria/prevención & control , Estenosis Coronaria/fisiopatología , Músculo Liso Vascular/efectos de los fármacos , Receptores Activados del Proliferador del Peroxisoma/antagonistas & inhibidores , Animales , Biomarcadores/sangre , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Enfermedad de la Arteria Coronaria/prevención & control , Estenosis Coronaria/prevención & control , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Músculo Liso Vascular/citología , Receptores Activados del Proliferador del Peroxisoma/metabolismo , Medición de Riesgo , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: Cell therapy is becoming a viable strategy to improve revascularization and myocardial function after myocardial injury. We evaluated the effect of bone marrow-derived mononuclear cell (BMMNC) transplantation on collateral vessel development and myocardial function in a porcine model of chronically infarcted heart. METHODS: Myocardial infarction was produced in 13 domestic swine. At 4 weeks, animals were randomized to receive transepicardial injections of autologous BMMNCs (approximately 24x10(6) cells, n=8) or phosphate buffered saline (PBS; control, n=5) into infarcted and border regions. Collateral growth, angiogenesis, and infarct size were assessed by angiography, immunohistochemistry, and histomorphometry. RESULTS: Regional contractility was assessed by transepicardial echocardiography at baseline and 4 weeks following treatment. Angiography revealed a trend toward increased collateral growth in the BMMNC group. Wall motion score index (myocardial function) was similar in both groups at baseline (1.63+/-0.16 vs. 1.25+/-0.25, P=.21) and at 4 weeks (1.83+/-0.22 vs. 1.63+/-0.38, P=.62). alpha-Actin-positive smooth muscle cells (SMCs) and Factor VIII positive endothelial cells were significantly greater in the BMMNC-injected animals (314.8+/-37.4/0.1 vs. 167.1+/-11.9/0.1 mm(2) in controls, P=.02, and 363.3+/-28.2 cells/0.1 mm(2) vs. 254.4+/-28.1 cells/0.1 mm(2) in controls, P=.03, respectively). The number of blood vessels >50 mum in diameter was significantly increased in the BMMNC group (317.9+/-54.9 vs. 149.1+/-6.1, P<.05). The size of the infarct area was smaller in the BMMNC-transplanted group than in the controls (P=.015). CONCLUSION: BMMNC transplantation appears to improve angiogenesis and reduce infarct size yet results in no improvement in left ventricular function in a chronically infarcted heart.
Asunto(s)
Trasplante de Médula Ósea/métodos , Monocitos/trasplante , Infarto del Miocardio/terapia , Animales , Enfermedad Crónica , Circulación Colateral , Angiografía Coronaria , Modelos Animales de Enfermedad , Ecocardiografía , Técnicas para Inmunoenzimas , Infarto del Miocardio/diagnóstico por imagen , Infarto del Miocardio/fisiopatología , Neovascularización Fisiológica/fisiología , Distribución Aleatoria , Porcinos , Trasplante AutólogoRESUMEN
Constitutive activation of serine/threonine kinase Akt causes uncontrolled cell-cycle progression in different cell types and in malignancy. To investigate how Akt activation modulates cell-cycle progression in vascular smooth muscle cells (SMCs) in vitro and in the intact animal, we inhibited Akt-dependent signaling by adenovirus-mediated transfection of a dominant-negative Akt mutant (AA-Akt). We observed reduced proliferation rate (P<0.01), DNA synthesis (P<0.01), and a significant arrest in G1/S exit (P<0.01) both in vitro in response to serum stimulation and in vivo after vascular injury. In vivo transfection of the balloon-injured vessel with AA-Akt reduced SMC proliferation, resulting in decreased neointima compared with control virus (P<0.01). These effects were at least in part modulated, both in vitro and in vivo, by increased p21Cip1 expression, as demonstrated by lack of effect of AA-Akt on cell proliferation in p21-/- mouse SMCs. In conclusion, this study demonstrates that Akt-dependent signaling enhances cell-cycle progression of nontransformed SMCs in vitro and in response to vascular injury in the intact animal. These results suggest a role for Akt signaling in modulating the response of normal tissues to stress and the response of the arterial wall to acute and possibly repetitive injuries that ultimately contribute to restenosis and atherosclerosis.
Asunto(s)
Fase G1/fisiología , Músculo Liso Vascular/metabolismo , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas/metabolismo , Fase S/fisiología , Adenoviridae/genética , Angioplastia de Balón/efectos adversos , Animales , Proteínas Sanguíneas/farmacología , Estenosis Carotídea/etiología , Estenosis Carotídea/patología , Estenosis Carotídea/terapia , División Celular/efectos de los fármacos , División Celular/fisiología , Células Cultivadas , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/deficiencia , Ciclinas/genética , Ciclinas/metabolismo , Modelos Animales de Enfermedad , Genes Dominantes , Terapia Genética/métodos , Oclusión de Injerto Vascular/etiología , Masculino , Ratones , Ratones Noqueados , Músculo Liso Vascular/citología , Músculo Liso Vascular/efectos de los fármacos , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-akt , Ratas , Ratas Sprague-Dawley , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Fase S/efectos de los fármacos , Transducción de Señal/fisiologíaRESUMEN
OBJECTIVES: We conducted a pilot study to evaluate the feasibility of transendocardial delivery of autologous bone marrow (ABM) strategy in patients with severe symptomatic chronic myocardial ischemia not amenable to conventional revascularization. BACKGROUND: Transendocardial injection of ABM cells appears to enhance perfusion of ischemic porcine myocardium. METHODS: Ten patients underwent transendocardial injection of freshly aspirated and filtered unfractionated ABM using left ventricular electromechanical guidance. Twelve injections of 0.2 ml each were successfully delivered into ischemic noninfarcted myocardium pre-identified by single-photon emission computed tomography perfusion imaging. RESULTS: Autologous bone marrow injection was successful in all patients and was associated with no serious adverse effects; in particular, there was no arrhythmia, evidence of infection, myocardial inflammation, or increased scar formation. Two patients were readmitted for recurrent chest pain. At three months, Canadian Cardiovascular Society angina score significantly improved (3.1 +/- 0.3 vs. 2.0 +/- 0.94, p = 0.001), as well as stress-induced ischemia occurring within the injected territories (2.1 +/- 0.8 vs. 1.6 +/- 0.8, p < 0.001). Treadmill exercise duration, available in nine patients, increased, but the change was not significant (391 +/- 155 vs. 485 +/- 198, p = 0.11). CONCLUSIONS: This study provides preliminary clinical data indicating feasibility of catheter-based transendocardial delivery of ABM to ischemic myocardium.
Asunto(s)
Trasplante de Médula Ósea , Enfermedad Coronaria/terapia , Miocardio , Cateterismo , Circulación Coronaria , Enfermedad Coronaria/diagnóstico por imagen , Estudios de Factibilidad , Femenino , Corazón/diagnóstico por imagen , Humanos , Inyecciones , Masculino , Persona de Mediana Edad , Proyectos Piloto , Tomografía Computarizada de Emisión de Fotón Único , Trasplante AutólogoRESUMEN
Bone marrow stem cells have been shown to differentiate into various phenotypes including cardiomyocytes, vascular endothelial cells and smooth muscle. Bone marrow stem cells are mobilized and home in to areas of injured myocardium where they are involved in tissue repair. In addition, bone marrow secretes multiple growth factors, which are essential for angiogenesis and arteriogenesis. In some patients, these processes are not enough to avert clinical symptoms of ischemic disease. Therefore, in vivo administration of an adequate number of stem cells would be a significant therapeutic advance. Unfractionated bone marrow derived mononuclear stem cells, which contain both hematopoietic and nonhematopoietic cells may be more appropriate for cell therapy. Studies in animal models suggest that implantation of different types of stem cells improve angiogenesis and arteriogenesis, tissue perfusion as well as left ventricular function. Several unanswered questions remain. For example, the optimal delivery approach, dosage and timing of the administration of cell therapy as well as durability of improvements need to be studied. Early clinical studies have demonstrated safety and feasibility of various cell therapies in ischemic disease. Randomized, double blind and placebo-controlled clinical trials need to be completed to determine the effectiveness of stem cell.
Asunto(s)
Enfermedad Crónica/terapia , Isquemia Miocárdica/terapia , Miocardio/citología , Miocardio/patología , Trasplante de Células Madre , Animales , Trasplante de Médula Ósea , Humanos , Miocitos Cardíacos/trasplanteRESUMEN
BACKGROUND: Controversy exists whether transmyocardial laser revascularization (TMR) is associated with angiogenesis or neuromodulation and whether these are time-dependent phenomena. Accordingly, we performed a time-course analysis of the expression of angiogenic and neuronal factors following experimental percutaneous TMR. METHODS AND RESULTS: Five weeks after placing ameroid constrictors on the circumflex coronary artery, 16 pigs underwent left ventricular mapping guided TMR using Ho:YAG laser (2 J x 1 pulse) at 30 sites directed at the ischemic zones and 11 animals were ischemic controls. Histology and immunostaining were obtained at 1 and 2 weeks (4 TMR and 3 controls at each time point) and at 4 weeks (8 TMR and 5 controls) for vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), nerve growth factor (betaNGF), substance P (SP), and monocyte chemoattractant protein-1 (MCP-1). Immunoreactivity was scored using a digital image analysis system. Factor VIII staining was used for blood vessel counting. Enhanced regional expression of VEGF, bFGF and MCP-1 in the TMR group was noted at 1 and 2 weeks with a threefold increase at 4 weeks following TMR compared to controls. BetaNGF expression in the TMR group was enhanced at 1 and 2 weeks with subsequent decline at 4 weeks to the controls level. SP expression was not significantly different between groups at all time points. There was a twofold increase in the number of blood vessels in the TMR group at 4 weeks, which was not apparent earlier. CONCLUSIONS: These immunohistological findings suggest that cytokines expression compatible with angiogenesis and neuromodulation occurs early after TMR. Up-regulation of angiogenic and inflammatory cytokines may be more sustained than neuromodulation.