Cardiac Stem Cells Improve LV Function in Cardiomyopathy

November 23, 2011

November 22, 2011 (Orlando, Florida) — Results from a small phase 1 study provide some reason for optimism in the treatment of ischemic cardiomyopathy with autologous cardiac stem cells (CSCs) [1]. An intracoronary infusion of the stem cells improved left ventricular function and reduced infarct size in patients with heart failure after MI, report investigators.

The cardiac stem cells were isolated and expanded from 1 g of myocardial tissue harvested during cardiac surgery and were infused 113 days, on average, after surgery.

"Infusion of one million autologous CSCs is not associated with apparent adverse effects for up to one year and . . . results in a substantial improvement in left ventricular function four months after infusion and an even more pronounced improvement one year after infusion and is associated with increased functional capacity, improved quality of life, and reduced left ventricular scar size," according to Dr Robert Bolli (University of Louisville, Kentucky) and colleagues.

Published November 14, 2011 in the Lancet and presented last week at the American Heart Association (AHA) 2011 Scientific Sessions, the study, known as Stem Cells in Patients with Ischemic Cardiomyopathy (SCIPIO), included 16 patients with postinfarction left ventricular dysfunction. Among 14 patients who were analyzed, the left ventricular ejection fraction (LVEF) increased from 30.3% before the intracoronary infusion of cardiac stem cells to 38.5% four months after the infusion (p=0.001), with an even more pronounced increase observed in eight patients at one year. Among seven control patients, there was no change in ejection fraction. Infarct size, assessed by cardiac MRI in seven patients, was reduced 24% at four months and 30% at one year (p=0.04).

"CSCs are particularly attractive for cardiovascular applications because they normally reside in the adult heart and can be reproducibly isolated and expanded, even from endomyocardial biopsies," write Bolli and colleagues. "These cells are thought to replenish the pool of cardiac myocytes and cardiac vascular cells that die during an organism's lifetime."

The LateTIME Study

Data from a study of patients treated with autologous bone-marrow mononuclear cells did not show the same positive results, however [2]. In a study also presented at the AHA meeting and published in the November 16, 2011 issue of the Journal of the American Medical Association, Dr Jay Traverse (University of Minnesota, Minneapolis) and colleagues found that a late intracoronary infusion of bone-marrow cells in patients with MI and left ventricular dysfunction did not improve global or regional heart function.

From baseline to six months, the changes in mean LVEF among patients who received the bone-marrow cells, typically two to three weeks following MI, were not significantly different from those of patients who received placebo. Similarly, the ejection-fraction findings were consistent with the lack of significant difference in wall motion assessed by cardiac MRI when compared with placebo-infused patients.

"Patients recruited to the LateTIME trial constituted a high-risk cohort with depressed left ventricular function that persisted several weeks following successful revascularization with stenting," according to Traverse and colleagues. "Although retrospective analyses suggest that these patients may derive the most benefit from cell therapy in this setting, no improvement in left ventricular function was noted, even in the subgroup with the most depressed left ventricular ejection fraction."

The LateTIME study is the first study completed by the Cardiac Cell Therapy Research Network, a group established by the National Heart, Lung, and Blood Institute to "accelerate the development of cell-based therapies in the United States."

In positive bone-marrow–cell infusion news [3], Dr David Leistner (Goethe University, Frankfurt, Germany) presented five-year data from the Reinfusion of Enriched Progenitor Cells and Infarct Remodeling in AMI (REPAIR-AMI), which randomized 204 patients to receive intracoronary infusion of bone-marrow cells or placebo, and reported that the rate of death, recurrent MI, and revascularization was significantly lower among patients with the intracoronary infusion of bone-marrow–derived mononuclear cells compared with placebo (20 events in the placebo arm vs 11 in the bone-marrow mononuclear cell arm; p=0.03). An MRI analysis of left ventricular function also showed a sustained improvement in LVEF at five years.

The Bone Marrow Cells in Acute Myocardial Infarction (BAMI) study is currently testing whether intracoronary infusions of bone-marrow mononuclear cells will reduce mortality in patients with MI who have been successfully reperfused.


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