In vitro, IL-33 blocks the phenylephrine-mediated cardiomyocyte hypertrophy and the actions of angiotensin-II; interestingly, IL-33 treatment seems to adjust hypertrophy and ventricular fibrosis in mice exposed to ventricular pressure overload, but only in wild-type mice, while the perturbation of the ST2 gene determines a progressive hypertrophy and myocardial fibrosis in animal models [27]. This evidence concerns the gene IL33 and Myocardial fibrosis.