The impact of a phytoestrogen-rich diet on cardiac gene expression in the context of HCM

A soy diet worsens the progression of an inherited form of hypertrophic cardiomyopathy (HCM) in male mice when compared to casein-fed mice. Females are largely resistant to this diet effect and better preserve cardiac function. We hypothesized that the abundant phytoestrogens found in soy are mainly responsible for this diet-dependent phenotype. Indeed, feeding male mice a phytoestrogen-supplemented casein-based diet can recapitulate the negative outcome seen when male mice are fed a standard soy-based diet. To gain mechanistic insights into disease pathogenesis, we used Affymetrix microarrays to profile gene expression in left ventricular tissue from 2 month old HCM male and female mice as well as wild-type littermate controls. These mice were fed a phytoestrogen (genistein + daidzein)-supplemented casein-based diet. We identified a number of molecular pathways that could explain both the male and female phenotypes. Hearts from male and female wild-type or HCM C57BL/6 mice fed a phytoestrogen-supplemented (genistein and daidzein mix) casein-based diet were excised at 2 months of age. Total RNA was extracted from left ventricles. Biotin-labeled amplified RNA was hybridized to Affymetrix Mouse Genome 430 2.0 microarrays.