The combination of high dietary methionine plus cholesterol induces myocardial fibrosis in rabbits

Limited evidence suggests that myocardial fibrosis might be associated with dietary cardiovascular risk factors. Objective To investigate the effects of high dietary cholesterol, methionine (the precursor to homocysteine), and the combination of the two diets on myocardial fibrosis. Methods Rabbits were randomly allocated into four dietary groups for 12 weeks: control (Con), 1% methionine (Meth), 0.5% cholesterol (Chol) or 1% methionine plus 0.5% cholesterol (MethChol). Results Myocardial fibrosis was not significantly increased in Chol or Meth. However, interstitial fibrosis increased by 85% (p = 0.03) and perivascular fibrosis 28-fold (p < 0.01) in the MethChol group compared to Con. Conclusions These results suggest that high levels of dietary cholesterol or methionine alone do not significantly increase myocardial collagen content. However, the combination of the two diets does cause myocardial fibrosis. Therefore, excessive cholesterol and methionine intake may be an important pathogenic factor in the development of myocardial fibrosis.