It was also found that decreased FGF21 levels were accompanied by significant cardiac dysfunction, remodelling and oxidative stress at 4 months after diabetes onset in WT diabetic mice, while FGF21 complete deletion significantly accelerated and aggravated the above-mentioned cardiac structural, functional and oxidative stress changes in FGF21KO diabetic mice (Figs4 and Table S1), which indicate that FGF21 plays a critical role in protecting the heart against the development of DCM under experimental type 1 diabetic conditions. Here, FGF21 is linked to diabetes mellitus.