PDK4 and familial dilated cardiomyopathy: While dermal fibroblasts and the cardiomyocytes that are implicated in DCM are very different cell types, a previous report demonstrated altered mitochondrial structure in heart muscle from PDK4 deficient dogs, we found that all four PDK isoforms found in the heart are also expressed in our dermal fibroblasts, and starvation has previously been shown to specifically upregulate PDK2 and PDK4 in the heart and we observed this same response in our fibroblasts8,33–35.