Further in vivo study by the same group demonstrated increased OPN and H2O2 levels in ligated femoral arteries compared with controls [315] and scavenging of H2O2 with polyethylene glycol-catalase infusion and SMC-specific catalase overexpression blunted ischemia-induced OPN, suggesting a crucial role of H2O2 in the induction of OPN expression during ischemia. Here, CAT is linked to ischemia.