Adipokine levels and cardiovascular risk in patients with adrenal incidentaloma

Adrenal incidentalomas (AIs) have been associated with an increased incidence of several cardiovascular risk factors, similar to overt Cushing syndrome. Data about the involvement of the adipokines in the development of insulin resistance and atherosclerosis in AI are completely lacking. The aim of the present study was to evaluate plasma interleukin 6 (IL-6), adiponectin, resistin, tumor necrosis factor alpha (TNF-alpha), and monocyte chemoattractant protein 1 (MCP-1) levels in patients with AI. Plasma IL-6, adiponectin, resistin, TNF-alpha, and MCP-1 levels were measured in 20 healthy subjects (6 males; 14 females; age, 58.5 +/- 2.2 years; body mass index, 28.1 +/- 0.9 kg/m(2)) and in 20 patients (5 males; 15 females; age, 57.9 +/- 2.0 years; body mass index, 28.0 +/- 0.8 kg/m(2)) with AI and typical computed tomographic features of cortical adenoma, who were not affected by diabetes mellitus, hypertension, or other relevant diseases. All patients underwent anthropometric measurements and determination of basal corticotropin, cortisol, and urinary free cortisol excretion. Overnight dexamethasone test and 250-microg corticotropin test were performed in all cases. A subclinical Cushing syndrome was found in 3 patients, whereas the others had apparently nonfunctioning masses. Plasma IL-6, adiponectin, resistin, TNF-alpha, and MCP-1 levels were higher in patients than in controls (64.4 +/- 2.8 vs 5.5 +/- 0.6 pg/mL, 13.7 +/- 1.3 vs 3.6 +/- 0.5 microg/mL, 12.5 +/- 1.9 vs 5.1 +/- 0.2 ng/mL, 27.0 +/- 1.5 vs 22.2 +/- 1.5 pg/mL, 172.5 +/- 20.0 vs 104.4 +/- 19.5 pg/mL, respectively; P < .05) and apparently not affected by the presence of visceral obesity. Plasma IL-6 levels were negatively correlated with urinary free cortisol (r = -0.461, P < .05), and TNF-alpha levels were positively correlated with cortisol after the administration of 1 mg dexamethasone (r = 0.636, P < .01). In conclusion, patients with AI may show increased levels of adipokines (apparently not related to the presence of diabetes, hypertension, or obesity), which may be affected by the presence of the adrenal adenoma. For some adipokines, a direct production from the adrenal gland may be hypothesized even if other studies are needed to better investigate the role of adipokines in states of altered cortisol secretion.