Because ABCB8 deletion in mouse hearts results in mitochondrial iron accumulation and cardiomyopathy, we investigated the role of endothelial ABCB8 in vascular function without systemic confounders by generating tamoxifen-inducible endothelial-specific Abcb8 knockout mice carrying two floxed conditional null Abcb8 alleles [21] and a Cdh5(PAC)-iCreERT2 [24]. The gene discussed is CDH5; the disease is cardiomyopathy.