In animal study, we found that at the early-stage of diabetes serum FGF21 level of mice was sharply increased compared with nondiabetic mice (C57BL/6J), while it was dramatically decreased at the late-stage of diabetes which further confirmed that early-stage increase of serum FGF21 was a compensatory response and induced beneficial effect on the heart; late-stage decrease may be the cause of diabetes-induced cardiac damage [30], since the above CVDs are always attributed to lipid metabolic disorder. The gene discussed is FGF21; the disease is diabetes mellitus.