Efficacy of CD34⁺ stem cell therapy in nonischemic dilated cardiomyopathy is absent in patients with diabetes but preserved in patients with insulin resistance

We evaluated the association of diabetes and insulin resistance with the response to cell therapy in patients with nonischemic dilated cardiomyopathy (DCM). A total of 45 outpatients with DCM received granulocyte colony-stimulating factor for 5 days. CD34⁺ cells were then collected by apheresis and injected transendocardially. Twelve patients had diabetes mellitus (DM group), 17 had insulin resistance (IR group), and 16 displayed normal glucose metabolism (no-IR group). After stimulation, we found higher numbers of CD34⁺ cells in the IR group (94 ± 73×10⁶ cells per liter) than in the no-IR group (54 ± 35 × 10⁶ cells per liter) or DM group (31 ± 20 × 10⁶ cells per liter; p =.005). Similarly, apheresis yielded the highest numbers of CD34⁺ cells in the IR group (IR group, 21661103106 cells; no-IR group, 127 ± 82 × 10⁶ cells;DMgroup, 77 ± 83×10⁶ cells; p =.002). Six months after cell therapy, we found an increase in left ventricular ejection fraction in the IR group (+5.6%66.9%) and the no-IR group (+4.4% 6 7.2%) but not in the DM group (20.9% 6 5.4%; p =.035). The N-terminal probrain natriuretic peptide levels decreased in the IR and no-IR groups, but not in theDMgroup (-606 ± 850 pg/ml; -698 ± 1,105 pg/ml; and +238 ± 963 pg/ml, respectively; p =.034). Transendocardial CD34⁺ cell therapy appears to be ineffective in DCM patients with diabetes. IR was associated with improved CD34⁺ stem cell mobilization and a preserved clinical response to cell therapy.