When mRNA encoding dominant-negative mutants of the Igf1 receptor and insulin receptor substrate 1 (Irs1) were applied to the heart surface of adult mice as a gel to inhibit Igf1 signaling in epicardial cells, it reduced the expression of adipogenic markers as well as the fraction of hearts with epicardial adipose tissue 28 days after MI. The gene discussed is IGF1; the disease is myocardial infarction.