Angiogenic pretreatment to enhance myocardial function after cellular cardiomyoplasty with skeletal myoblasts.

OBJECTIVE: Improvements in ventricular function after cellular cardiomyoplasty appear to be limited by the poor survival of the cellular implants. Angiogenic pretreatment of infarcted myocardium may improve implanted cell survival and consequently myocardial function. METHODS: Fischer 344 rats underwent coronary artery ligation and injection of an adenovirus encoding vascular endothelial growth factor 121 or of saline solution at increasing intervals after ligation. Myocardial perfusion and mass preservation were assessed. On the basis of these data, four groups of animals underwent coronary ligation and adenovirus with or without syngeneic skeletal myoblast administration: (1) adenovirus at ligation and myoblasts 3 weeks later (n = 7), (2) saline solution at ligation and myoblasts 3 weeks later (n = 8), (3) saline solution at ligation and 3 weeks later (n = 8), and (4) saline solution at ligation and adenovirus with myoblasts 3 weeks later (n = 5). Left ventricular ejection fraction was analyzed by echocardiography before coronary ligation and 3 and 5 weeks later, after which cell survival was assessed in harvested tissues. RESULTS: Myocardial infarct perfusion was at least 50% greater in animals treated with adenoviral vector than with saline solution immediately after ligation (P < .02). In comparison, delayed adenovirus administration did not significantly diminish infarct perfusion but resulted in decreased myocardial preservation (P < .05). Accordingly, adenovirus administration nearly tripled implanted myoblast survival relative to saline solution-treated animals (P = .004). Left ventricular ejection fraction was improved, however, only after cell implantation with adenovirus pretreatment (P = .027). CONCLUSION: Angiogenic strategies can help to preserve myocardium jeopardized by acute coronary occlusions. Angiogenic pretreatment enhances the efficacy of cellular cardiomyoplasty.

Gadofluorine-enhanced magnetic resonance imaging of carotid atherosclerosis in Yucatan miniswine.

OBJECTIVE: The aim of this study was to determine whether gadofluorine, a paramagnetic magnetic resonance imaging (MRI) contrast agent, selectively enhances carotid atherosclerotic plaques in Yucatan miniswine. METHODS: Atherosclerotic plaques were induced in the left carotid arteries (LCA) of Yucatan miniswine (n=3) by balloon denudation and high cholesterol diet. T1-weighted MRI was performed before and 24 hours after gadofluorine injection (at a dose of 100 micromol/kg) to assess the enhancement of the balloon-injured LCA wall relative to healthy, uninjured right carotid artery (RCA) wall. Histopathology was performed to verify the presence and composition of the atherosclerotic plaques imaged with MRI. RESULTS: Gadofluorine was found to enhance LCA atherosclerotic lesions relative to RCA wall by 21% (P<0.025) 24 hours after contrast injection. Enhancement of healthy LCA wall relative to healthy RCA wall was not observed. CONCLUSION: Gadofluorine selectively enhances carotid atherosclerotic plaques in Yucatan miniswine. Gadofluorine appears to be a promising MR contrast agent for detection of atherosclerotic plaques in vivo.

Porcine carotid arterial material property alterations with induced atheroma: an in vivo study.

OBJECTIVE: A novel methodology has been developed to evaluate regional alterations in arterial wall material properties with induced atheroma in an animal model. METHODS: Atheromatous lesions (fatty, fibro-fatty, and fibrous) were induced in the carotid arteries of a Yucatan miniswine model by endothelial cell denudation and high cholesterol diet. The images at base line and 8 weeks after denudation were obtained using intravascular ultrasound (IVUS) imaging along with hemodynamic data. Finite element analysis (FEA) along with optimization was employed to assess regional alterations in elastic modulus in the presence of atheroma confirmed by histology. RESULTS: In animals with 8 weeks of induced atherosclerosis, the elastic modulus increased-(elastic modulus-all values x 10(4) Pa, mean+/-S.D.) normal elements (9.34+/-0.36) compared to abnormal elements (9.52+/-0.36) (p<0.05 versus normal elements). Wall thickness increased with atheroma formation. These data demonstrate stiffening vascular wall elastic modulus with lesion progression. This is different from the behavior of femoral arteries, where the elastic modulus decreases with early stages of atheroma development followed by an increase as lesions progress. CONCLUSIONS: This methodology permits determination of areas with early atheroma development, follow atheroma progression, and potentially evaluate interventions aimed at decreasing atheroma load and normalizing vascular material properties.