Atorvastatin accelerates extracellular nucleotide degradation in human endothelial cells

Purinergic signaling and blood vessels in health and disease

Purinergic signaling plays important roles in control of vascular tone and remodeling. There is dual control of vascular tone by ATP released as a cotransmitter with noradrenaline from perivascular sympathetic nerves to cause vasoconstriction via P2X1 receptors, whereas ATP released from endothelial cells in response to changes in blood flow (producing shear stress) or hypoxia acts on P2X and P2Y receptors on endothelial cells to produce nitric oxide and endothelium-derived hyperpolarizing factor, which dilates vessels. ATP is also released from sensory-motor nerves during antidromic reflex activity to produce relaxation of some blood vessels. In this review, we stress the differences in neural and endothelial factors in purinergic control of different blood vessels. The long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides in promoting migration and proliferation of both vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis and vessel remodeling during restenosis after angioplasty are described. The pathophysiology of blood vessels and therapeutic potential of purinergic agents in diseases, including hypertension, atherosclerosis, ischemia, thrombosis and stroke, diabetes, and migraine, is discussed.

Upregulation of ecto-5'-nucleotidase by rosuvastatin increases the vasodilator response to ischemia

3-Hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) are effective in the primary and secondary prevention of cardiovascular events. Although originally developed to improve lipid profile, statins have demonstrated a surplus of beneficial pleiotropic effects, including improved endothelial function, reduced inflammation, and increased tolerance to ischemia-reperfusion injury. In preclinical studies, increased ecto-5'-nucleotidase activity, the key enzyme in extracellular adenosine formation, plays an important role in these effects. Because human data are absent, we explored the effects of rosuvastatin on ecto-5'-nucleotidase activity and the clinical relevance of increased extracellular adenosine during ischemia in humans in vivo. The forearm vasodilator responses to 3 increasing periods of forearm ischemia (2, 5, and 13 minutes) were determined during placebo and caffeine (an adenosine receptor antagonist) infusion into the brachial artery. At the end of an 8-day treatment period with rosuvastatin (20 mg per day), this whole procedure was repeated. During both experiments, ecto-5'-nucleotidase activity was determined. Vasodilator responses are expressed as the percentage increase in forearm blood flow ratio from baseline. Rosuvastatin increased ecto-5'-nucleotidase activity by 49±17% and enhanced the vasodilator response after 2, 5, and 13 minutes of ischemia in the absence (146±19, 330±26, and 987±133 to 312±77, 566±107, and 1533±267) but not in the presence of caffeine (98±25, 264±54, and 727±111 versus 95±19, 205±34, and 530±62). Rosuvastatin increases extracellular formation of adenosine in humans in vivo probably by enhancing ecto-5'-nucleotidase activity. This action results in the improvement of reactive hyperemia and may further enhance the clinical benefit of statins, in particular in conditions of ischemia.