ACTA1 and heart failure: To investigate whether increased GPC6 levels were associated with severity and progression of disease, GPC6 mRNA in sham- and AB-operated mouse hearts was correlated with LV weight, expression of the hypertrophic signature gene ACTA1 (encoding α-skeletal actin), lung weight and heart failure signature genes NPPA and NPPB (encoding atrial and brain natriuretic peptides, ANP and BNP, respectively).