Trial of the Effects of Remote Preconditioning on the Tissue Metabolism During Exercise and Ischemia

Ischemic preconditioning is a mechanism that protects tissue against ischemia-reperfusion injury. The protective effect of preconditioning is induced by short periods (1-5 minutes) of non-lethal ischemia to the target tissue, which becomes resistant to a prolonged, otherwise lethal, period of ischemia. Despite its proven potency in experimental models, ischemic preconditioning has not reached widespread clinical application because of the difficulties in applying the stimulus to the target organ (eg Heart, Brain), and even brief ischemia to the target organ can cause dysfunction.

Remote ischemic preconditioning (RIPC) is a more clinically relevant stimulus. It has been shown that preconditioning of one coronary territory induces ischemia protection in other parts of the heart. Subsequently, other studies have shown, in rodent models, that preconditioning of one organ (eg kidney) could induce protection in other organs (eg heart). We recently have confirmed, in a series of animal and human preclinical studies, that this concept can be widened; ultimately showing that four 5-minute episodes of ischemia to the skeletal limb muscles (induced by inflating a standard blood pressure cuff to a level higher than the blood pressure) protects the heart and lungs against ischemia-reperfusion injury in children undergoing cardiac surgery using cardiopulmonary bypass.

The current research is designed to investigate with MRI spectroscopy techonology, the potential physiological mechanisms involved in the protective effects of preconditioning, and the effects of ischemia and exercise.