Adenosine and chronic ischemia of the lower limbs

Adenosine is an endogenous nucleoside with multiple biological properties w hich plays a central role in the pathophysiology of tissue ischemia. Adenos ine signals an imbalance between oxygen demand and supply, and it initiates responses to redress such a discrepancy. Besides its vasodilating properti es, adenosine possesses anti-platelet and anti-neutrophil activities and pr ovides cytoprotection. Adenosine is presumably the main mediator of the pre conditioning phenomenon. During ischemia of the lower limbs, adenosine play s a physiological role by inducing vasodilatation and by preventing microci rculatory failure. Exercise training prolongs claudication distance possibl y by inducing pulse increases of adenosine and consequently skeletal muscle preconditioning. Moreover, the adenosine increase which follows the admini stration of some drugs, such as buflomedil and propionylcarnitine, opens ne w perspectives in the management of leg ischemia. In fact, the concept aris es of an ischemic (exercise-dependent) or pharmacologic preconditioning in the treatment of patients with claudication.