Plasma asymmetric dimethylarginine (ADMA) levels and atherosclerotic disease in ankylosing spondylitis: a cross-sectional study

Conclusive data about the prevalence of endothelial dysfunction and atherosclerotic process in ankylosing spondylitis (AS) patients with respect to the general population are lacking. Elevated plasma levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, have been reported in clinical conditions associated with endothelial dysfunction and atherosclerotic disease. We performed a cross-sectional study to evaluate plasma ADMA levels and atherosclerotic disease in AS patients. Seventeen consecutive AS patients free of any cardiovascular disease and 17 healthy controls [strictly matched for sex, age (+/- 5 years) and atherosclerotic risk factors] were recruited. Plasma ADMA levels were assessed by capillary electrophoresis. Common carotid artery intima media thickness (CCA-IMT), flow-mediated dilatation (FMD) and arterial stiffness (aS) were registered as surrogate markers of atherosclerotic disease. Plasma ADMA levels appeared significantly (p=0.001) higher in AS patients (0.65 +/- 0.10 mu moli/L) than in the control subjects (0.54 +/- 0.07 mu moli/L) while no statistically significant differences between AS and controls were demonstrated in CCA-IMT, FMD, and aS. AS patients showed increased plasma ADMA levels with respect to control subjects. On the contrary, we were not able to document a significant difference in atherosclerotic process between patients and controls.