Direct intramyocardial percutaneous delivery of autologous bone marrow in patients with refractory myocardial angina

Cellular transplantation: future therapeutic options

PURPOSE OF REVIEW

Cardiac transplantation is a complex undertaking and an imperfect solution to end-stage heart failure. Cellular transplantation has been proposed as an alternative solution; however, clinical trials at present are small and show variable results. The mechanisms behind stem cell therapy have not yet been elucidated.

RECENT FINDINGS

Several large trials have been presented that address the question of bone marrow stem cells as therapy for acute myocardial infarction, and also the possible benefits of therapy with granulocyte colony-stimulating factor. Although some trials show a modest improvement in ejection fraction or reduction of infarct size, other trials show no change with treatment. Fewer clinical data are available on the treatment of chronic left ventricular systolic function. Many questions remain such as what cell type to use, dosing, the ideal timing for therapy, and the technique of cell delivery. Finally, further research continues on the cellular milieu, enhancement of cell engraftment, proliferation, and survival.

SUMMARY

This review briefly examines the background for stem cell therapy, as well as the larger clinical trials of stem cell therapy for acute myocardial infarction and chronic left ventricular systolic dysfunction, and possible pharmacologic enhancement options.

Present and future of stem cells for cardiovascular therapy

In this review we summarize the available evidence regarding the application of stem cell therapy for human cardiovascular repair, going over the principal concepts that will help us understand the present and future of this therapy: first the different types of cells available in clinical practice, second the delivery approaches, and third highlighting the most important clinical studies and their efficacy and safety results. In addition, we also speculate on the value of current clinical data to gain an insight into the mechanism of stem cell-based cardiac repair and to design clinical trials in the future.

Simultaneous isolation of human BM hematopoietic, endothelial and mesenchymal progenitor cells by flow sorting based on aldehyde dehydrogenase activity: implications for cell therapy

BACKGROUND

ALDH(br) cells express high aldehyde dehydrogenase (ALDH) activity and have progenitor cell activity in several contexts. We characterized human BM ALDH(br) cells to determine whether cell sorting based on ALDH activity isolates potentially useful populations for cell therapy.

METHOD

We measured the expression of ALDH and cell-surface Ag by flow cytometry and compared the ability of sorted ALDH(br), and BM populations remaining after ALDH(br) cells were removed (ALDH(dim) populations), to develop into several cell lineages in culture.

RESULTS

The ALDH(br) population comprised 1.2+/-0.8% (mean+/-SD, n=30) nucleated cells and was enriched in cells expressing CD34, CD117, CD105, CD127, CD133 and CD166, and in primitive CD34(+) CD38(-) and CD34(+) CD133(+) progenitors. Most of the CD34(+) and CD133(+) cells were ALDH(dim). ALDH(br) populations had 144-fold more hematopoietic colony-forming activity than ALDH(dim) cells and included all megakaryocyte progenitors. ALDH(br) populations readily established endothelial cell monolayers in cultures. Cells generating endothelial colonies in 7 days were 435-fold more frequent in ALDH(br) than ALDH(dim) populations. CFU-F were 9.5-fold more frequent in ALDH(br) than ALDH(dim) cells, and ALDH(br) cells gave rise to multipotential mesenchymal cell cultures that could be driven to develop into adipocytes, osteoblasts and chondrocytes.

DISCUSSION

Hematopoietic, endothelial and mesenchymal progenitor cells can be isolated simultaneously from human BM by cell sorting based on ALDH activity. BM ALDH(br) populations may be useful in several cell therapy applications.

Sustained effect of autologous bone marrow mononuclear cell injection in patients with refractory angina pectoris and chronic myocardial ischemia: twelve-month follow-up results

BACKGROUND

Cell therapy has recently been introduced to treat patients with refractory angina. Because most studies have only included short-term follow-up, the effects of cell therapy over a longer period are unknown.

METHODS

In 25 patients (mean age 64 +/- 10 years, 21 men) with refractory angina, a total of 84 +/- 29 x 10(6) bone marrow-derived mononuclear cells was injected intramyocardially in regions with ischemia on technetium-99m tetrofosmin single-photon emission computed tomography. Anginal symptoms and quality of life were evaluated at baseline and at 3, 6, and 12 months. Gated single-photon emission computed tomography was performed at baseline and at 3 and 12 months to assess myocardial perfusion and left ventricular function.

RESULTS

Bone marrow cell injection was performed without any complication. At 7 months, one patient died of intracranial hemorrhage. Canadian Cardiovascular Society class improved from 3.4 +/- 0.5 to 2.3 +/- 0.6 at 3 months, 2.4 +/- 0.6 at 6 months, and 2.7 +/- 0.8 at 12 months (P < .01). Quality of life improved from 53% +/- 10% to 71% +/- 11% at 3 months, 72% +/- 14% at 6 months, and 68% +/- 14% at 12 months (P < .01). The number of segments with ischemia per patient decreased from 4.7 +/- 3.3 to 2.1 +/- 2.6 at 3 months and 1.6 +/- 2.5 at 12 months (P < .01). Left ventricular ejection fraction increased from 47% +/- 13% to 53% +/- 17% at 3 months and 51% +/- 17% at 12 months (P < .01). Regional wall motion improved from 5.9 +/- 1.7 to 6.6 +/- 2.2 mm at 3 months and 6.4 +/- 2.0 mm at 12 months (P = .01).

CONCLUSIONS

Autologous bone marrow cell injection in patients with ischemia is safe and results in a sustained beneficial effect on anginal symptoms, myocardial perfusion, and left ventricular function.