1. Skeletal Myoblast Cells

2. 2 Skeletal myoblasts Derived from satellite cells in skeletal muscle With appropriate stimulus, satellite cells differentiate into muscle fibers Highly resistant to ischemia Do not contract spontaneously Do not differentiate into cardiomyocytes

3. 3 Human skeletal myoblasts after 3-wk in vitro culture period (magnification ×40) Skeletal myoblasts 2-3 cm biopsy sample of thigh vastus lateralis (12-18 g) explanted under local anesthesia Courtesy of Arshed A. Quyyumi, MD.

4. 4 Before surgery After surgery Menasché P et al. Lancet. 2001;357:279-80. Skeletal myoblast transplantation in post-MI HF patients

5. 5 Autologous skeletal myoblast injection for ischemic cardiomyopathy trial (MAGIC) Patients: –Moderate to severe LVSD referred for CABG Cells: –Muscle Bx from thigh –Skeletal muscle myoblasts cultured Delivery: –Direct injection into scar at surgery Results: –Stopped early by DSMB due to low enrollment rate –Adverse event rate similar (25% cells vs 20% controls) –ICD Therapy in 15% –No improvement in LVEF by TTE (primary outcome)* –LVEF improved by SPECT –Highly significant dose-dependent LV size decrease Cleland JGF et al. Eur J Heart Failure 2007;9:92-97. Placebo Low-Dose Myoblasts High-Dose MyoblastP value Patients enrolled 413940 Patients injected 343330 Change in LVEF (echo)* +4.4%+3.4%+5.2% NS Change in LVEF (nuc) 02%3% <0.04 Change in LVEDD (mL) +9 (-21 to 28) -9 (-33 to 25) -23 (-42 to 0) 0.006