Eight weeks after TAC surgery, Igfbp7 deficiency resulted in downregulation of multiple signal transduction mediators of the IGF-1R/IRS signaling pathway, evidenced by reduced phosphorylation of Igf-1rβ (Fig. 5a) and insulin receptor substrate (IRS-1) (Fig. 5b). This evidence concerns the gene IGFBP7 and persistent truncus arteriosus.