Figure 1.

The timing and the potential mechanisms underlying remote ischemic conditioning (RIC). The RIC stimulus can be applied prior to ischemia (preconditioning), after the onset of ischemia (perconditioning), or at the time of reperfusion (postconditioning). A variety of intracellular signaling mediators have been implicated in the protective effect of RIC. Three main mechanisms for transmitting the protective signal from the organ or tissue, in which the RIC stimulus is applied, to the target organ or tissue (these are not mutually exclusive): (1) neural pathway, (2) the release of circulating humoral factor(s), and (3) activation of a systemic protective effect (such as an anti-apoptotic or anti-inflammatory response).