Autologous skeletal myoblast transplantation for severe postinfarction left ventricular dysfunction.

OBJECTIVES: This phase I trial was designed to assess the feasibility and safety of autologous skeletal myoblast transplantation in patients with severe ischemic cardiomyopathy. BACKGROUND: Experimentally, myoblast grafting into postinfarction myocardial scars improves left ventricular function. METHODS: Ten patients were included on the basis of the following criteria: 1) severe left ventricular dysfunction (ejection fraction < or = 35%); 2) the presence of a postinfarction akinetic and nonviable scar, as assessed by dobutamine echocardiography and 18-fluorodeoxyglucose positron emission tomography; and 3) an indication of coronary bypass in remote areas. Skeletal myoblasts were grown from a biopsy taken at the thigh. RESULTS: An average of 871 x 10(6) cells (86% of myoblasts) were obtained after a mean period of 16 days and implanted uneventfully across the scar at the time of bypass. Except for one patient whose early death was unrelated to the cell transplantation, all patients had an uncomplicated postoperative course. Four patients showed delayed episodes of sustained ventricular tachycardia and were implanted with an internal defibrillator. At an average follow-up of 10.9 months, the mean New York Heart Association functional class improved from 2.7 +/- 0.2 preoperatively to 1.6 +/- 0.1 postoperatively (p < 0.0001), and the ejection fraction increased from 24 +/- 1% to 32 +/- 1% (p < 0.02). A blinded echocardiographic analysis showed that 63% of the cell-implanted scars (14 of 22) demonstrated improved systolic thickening. One noncardiac death occurred 17.5 months after transplantation. CONCLUSIONS: These preliminary data suggest the feasibility and safety of autologous skeletal myoblast transplantation in severe ischemic cardiomyopathy, with the caveat of an arrhythmogenic potential. New-onset contraction of akinetic and nonviable segments suggests a functional efficacy that requires confirmation by randomized studies.

Homozygous deletion of early growth response 1 gene and critical limb ischemia after vascular ligation in mice: evidence for a central role in vascular homeostasis.

BACKGROUND: The early growth response 1 gene (Egr1) encodes for an immediate to early response transcription factor that is upregulated by changes in vascular strain and hypoxia and in turn upregulates the downstream expressions of a number of angiogenic growth factors. We therefore hypothesized that early growth response 1 may be a critical early messenger governing revascularization in the setting of acute vascular occlusions. METHODS: C57 BL/6 mice deficient in the Egr1 gene (knockout) and their wild-type litter mates underwent ligation and excision of the femoral artery with or without the previous administration of 2.7 x 10(9) particle units of an adenoviral vector coding for the vascular endothelial growth factor gene (VEGF) or Egr1. Distal hind limb perfusion was serially measured in these animals with laser Doppler perfusion imaging. RESULTS: Wild-type mice (n = 9) had nearly complete restitution of hind limb perfusion by day 35 after ligation. In contrast, all noninjected Egr1 knockout mice (n = 5) had severe ipsilateral limb necrosis develop between 1 and 4 days after ligation (P <.0001). Egr1 knockout mice injected with VEGF vector (n = 4) demonstrated significantly improved perfusion relative to baseline by postligation day 28, which persisted to postligation day 35 (P <.05). Egr1 knockout animals injected with Egr1 vector (n = 7) demonstrated a partial recovery of hind limb perfusion relative to VEGF vector-treated knockout animals at postligation day 4 (P <.01), which persisted to day 35. CONCLUSIONS: These findings suggest that early growth response 1 plays a pivotal role in reperfusion responses to vascular occlusion in mice and possibly other mammals.

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.