Interestingly, downregulation of PPARα and upregulation of Noxs, particularly Nox2, play critical and independent roles in cardiac hypertrophy [6,12,31], and these effects often manifest as opposing actions on key signalling pathways, such as Akt, AP-1, NF-κB and MAPKs, which are differentially regulated by PPARα and Nox2. This evidence concerns the gene CYBB and cardiac hypertrophy.