Although we can exclude the influence of circulating RAS (because we used the isolated hearts with Langendorff-perfusion and application of angiotensin receptor blocker valsartan did not alter the ischemic resistance in DM hearts [4]), we cannot deny the possibility that secreting renin (instead of ns-renin) would contribute to the ischemic resistance in DM hearts via autocrine and/or paracrine signaling. Here, REN is linked to diabetes mellitus.