The nitric oxide-donating derivative of acetylsalicylic acid, NCX 4016, stimulates glucose transport and glucose transporters translocation in 3T3-L1 adipocytes

NCX 4016 is a nitric oxide (NO)-donating derivative of acetylsalicylic acid. NO and salicylate, in vivo metabolites of NCX 4016, were shown to be potential actors in controlling glucose homeostasis. In this study, we evaluated the action of NCX 4016 on the capacity of 3T3-L1 adipocytes to transport glucose in basal and insulin-stimulated conditions. NCX 4016 induced a twofold increase in glucose uptake in parallel with the translocation of the glucose transporters GLUT1 and GLUT4 to the plasma membrane, leaving unaffected their total expression levels. Importantly, NCX 4016 further increased glucose transport induced by a physiological concentration of insulin. The stimulatory effect of NCX 4016 on glucose uptake appears to be mediated by its NO moiety. Indeed, it is inhibited by a NO scavenger and treatment with acetylsalicylic or salicylic acid had no effect. Although NO is involved in the action of NCX 4016, it did not mainly depend on the soluble cGMP cyclase/protein kinase G pathway. Furthermore, NCX 4016-stimulated glucose transport did not involve the insulin-signaling cascade required to stimulate glucose transport. NCX 4016 induces a small activation of the mitogen-activated protein kinases p38 and c-Jun NH2-terminal kinase and no activation of other stress-activated signaling molecules, including extracellular signal-regulated kinase, inhibitory factor κB, or AMP-activated kinases. Interestingly, NCX 4016 modified the content of S-nitrosylated proteins in adipocytes. Taken together, our results indicate that NCX 4016 induced glucose transport in adipocytes through a novel mechanism possibly involving S-nitrosylation. NCX 4016 thus possesses interesting characteristics to be considered as a candidate molecule for the treatment of patients suffering from metabolic syndrome and type 2 diabetes.

Roles of platelet and endothelial cell COX-1 in hypercholesterolemia-induced microvascular dysfunction

Aspirin is a common preventative therapy in patients at risk for cardiovascular diseases, yet little is known about how aspirin protects the vasculature in hypercholesterolemia. The present study determines whether aspirin, nitric oxide-releasing aspirin (NCX-4016), a selective cyclooxygenase (COX)-1 inhibitor (SC560), or genetic deficiency of COX-1 prevents the inflammatory and prothrombogenic phenotype assumed by hypercholesterolemic (HC) venules. Aspirin or NCX-4016 (60 mg/kg) was administered orally for the last week of a 2-wk HC diet. COX-1-deficient (COX-1−/−) and wild-type (WT) mice were transplanted with WT (WT/COX-1−/−) or COX-1−/−(COX-1−/−/WT) bone marrow, respectively. HC-induced adhesion of platelets and leukocytes in murine intestinal venules, observed with intravital fluorescence microscopy, was greatly attenuated in aspirin-treated mice. Adhesion of aspirin-treated platelets in HC venules was comparable to untreated platelets, whereas adhesion of SC560-treated platelets was significantly attenuated. HC-induced leukocyte and platelet adhesion in COX-1−/−/WT chimeras was comparable to that in SC560-treated mice, whereas the largest reductions in blood cell adhesion were in WT/COX-1−/−chimeras. NCX-4016 treatment of platelet recipients or donors attenuated leukocyte and platelet adhesion independent of platelet COX-1 inhibition. Platelet- and endothelial cell-associated COX-1 promote microvascular inflammation and thrombogenesis during hypercholesterolemia, yet nitric oxide-releasing aspirin directly inhibits platelets independent of COX-1.

Prevention by NCX 4016, a nitric oxide-donating aspirin, but not by aspirin, of the acute endothelial dysfunction induced by exercise in patients with intermittent claudication

SummaryIschemia/reperfusion damage evokes systemic inflammation and endothelial dysfunction in patients with intermittent claudication. We compared the effects of aspirin with those of a nitric oxide-donating aspirin in preventing the acute, systemic endothelial dysfunction provoked by exercise-induced ischemia of the lower limbs in patients with intermittent claudication. In a prospective, randomized, single-blind, parallel-groups trial among 44 patients with intermittent claudication we compared four weeks of aspirin (100 mg o.d.) with NCX 4016 (800 mg b.i.d.). Primary end point was the exercise-induced changes in brachial flow-mediated vasodilation (FMD) at day 28; secondary end points were effort-induced changes of markers of neutrophil (plasma elastase) and endothelial (soluble VCAM-1) activation. Baseline FMD was comparable in the two groups, both on day I (pre-treatment: aspirin = 3.1 ± 0.5%, nitroaspirin = 3.9 ± 0.7%, p=NS), and on day 28 (aspirin = 3.4 ± 0.7%, NCX 4016 = 3.2 ± 0.6%, p=NS). Maximal treadmill exercise induced an acute worsening of FMD in both groups at baseline (aspirin = –1.15%, nitroaspirin = –1.76%); after four weeks treatment, the impairment of FMD induced by exercise was still present in the aspirin-treated group (- 1.46%) while it was abolished in the NCX 4016-treated group (+ 0.79%, p= 0.038 vs. aspirin). Similarly, exercise induced an increase of plasma elastase and of sVCAM-l which were not affected by aspirin while they were suppressed by NCX 4016. Maximal treadmill exercise induces a systemic arterial endothelial dysfunction in patients with intermittent claudication. A nitric oxide-donating aspirin, but not aspirin, prevents effort-induced endothelial dysfunction.