Abstract 13991: Long-Term Effects of Autologous Transplantation of Immature Erythroblasts in Patients With Severe Peripheral Artery Disease
Background: Efficacy of angiogenesis therapy using bone marrow mononuclear cells (BMNCs) implantation in peripheral artery disease has been reported. We have recently found that immature erythroblasts, but not endothelial progenitor cells, play an essential role in angiogenesis. Here we report the effects of a novel cell therapy using immature erythroblasts in patients with severe limb ischemia.
Methods and Results: Immature to mature erythroblasts were purified from human bone marrow. The expression levels of VEGF and PLGF in immature erythroblasts was decreased through maturation indicating that erythroblasts have strong angiogenic effects at an early immature stage. To obtain very immature erythroblasts for angiogenesis therapy, we developed two-step culture methods; bone marrow cells were initially cultured with Flt-3 ligand, stem cell factor, and thrombopoietin for one week, and then were cultured with stem cell factor, insulin-like growth factor-I, and erythropoietin for one week. After the culture, the number of cells increased to enough level (32 times from baseline) for in vivo angiogenesis therapy. We compared the angiogenic effects of immature erythroblasts and BMNCs in mice with unilateral limb ischemia and found that blood perfusion was improved better by therapy with immature erythroblasts than that with BMNCs (laser Doppler ratio, 190% vs. 159% of placebo injection). Then, we tested the effects of autologous transplantation of immature erythroid cells in 7 patients with severe limb ischemia who were refractory to conventional therapy. After aspiration of bone marrow cells (69 ± 23 mL) followed by a 2-week culture, ischemic limbs were injected with immature erythroblasts. Symptoms were improved in all of the patients 4 weeks after the transplantation (visual analogue scale, 39.3 ± 10.0 to 29.1 ± 8.2). During a follow-up of 1.8 ± 0.9 years (range, 0.5 – 2.7 years), the effects of the transplantation persisted in all patients and no adverse effect occurred.
Conclusion: We developed a novel angiogenesis therapy using immature erythroblasts and revealed the long-term clinical effects. Our findings provide enough evidence to conduct further studies to confirm the efficacy and safety of the therapy in a large population. (ISRCTN66803682)
- © 2010 by American Heart Association, Inc.