IntroductionDespite the significant development of cardiology, little is still known about the molecular basis of myocardial remodelling under conditions of high fat, high cholesterol diet, which is known to be proatherogenic.PurposeThe aim of the project was to investigate whether a diet with high amount of fat and cholesterol contributes to changes in the expression of proteins regulating the structure of extracellular matrix in the heart muscle.MethodsThe study was conducted upon 20 ApoE−/− mice (Charles Rivers Laboratories, Inc.), which from the 10th week of age for the next 14 weeks were fed a standard diet (5% fat, 19.5% casein, Animalab) (n = 10 – control group) or high fat, high cholesterol diet (21% fat, 0,15% cholesterol, 19.5% casein; Animalab) (n = 10 – experimental group). At the end of the experiment, mice were euthanized to collect the heart for immunohistochemical analysis. In myocardium, levels of matrix metalloproteinase 1 (MMP‐1), matrix metalloproteinase 2 (MMP‐2), matrix metalloproteinase 9 (MMP‐9) and pro‐inflammatory cytokines ‐ interleukin 1β (IL‐1β), interleukin 6 (IL‐6) and interleukin 17 (IL‐17) were determined. In addition, the levels of type I collagen, type III collagen and tissue metalloproteinase inhibitor type 1 (TIMP‐1) were also examined in the myocardium. Consent was obtained from The Local Animal Research Ethics Committee (20/2015).ResultsApoE−/− mice in the experimental group had significantly higher body weight compared to the ApoE−/− mice in the control group. ApoE−/− mice in the experimental group showed significantly higher levels of MMP‐9 in myocardium compared to control mice. In contrast, TIMP‐1 expression was significantly higher in the control group compared to the experimental group. The high fat, high cholesterol diet also contributed to significantly higher expression of type I collagen and type III collagen in myocardium in the ApoE−/− mice. We also showed that the mice in the experimental group had significantly lower myocardial IL‐6 levels compared to the mice in the control group.ConclusionHigh fat, high cholesterol diet significantly affected the level of proteins regulating extracellular matrix structure in the ApoE−/− mice. It suggests, that the diet influences myocardial remodeling. This subject is worth of further investigations due to potential clinical implications.Support or Funding InformationThis research was supported by the Medical University of Warsaw, Young Researcher’s Grant (1MA/PM1/17/17).