Circulating adiponectin levels and cardiovascular risk factors in acromegalic patients

OBJECTIVE: Adiponectin (ApN) is an adipocytokine expressed in human adipose cells with anti-atherogenic and anti-inflammatory properties that plays a role in the pathophysiology of insulin resistance, metabolic syndrome and coronary artery disease. The aim of the study was to evaluate ApN secretion in patients with acromegaly, a chronic disease associated with insulin resistance and increased cardiovascular mortality, and to correlate ApN levels with hormonal, metabolic and cardiovascular parameters. DESIGN AND METHODS: The study included 32 patients with active acromegaly (11 male and 21 female, aged 48+/-11 years, duration of disease: 8+/-6 years, GH: 9.2+/-9.8 microg/l, IGF-I: 80+/-33 nmol/l (means+/-s.d.)) and 38 control subjects sex- and body mass index (BMI)-matched. In all subjects, serum ApN, leptin and ghrelin levels, BMI, waist circumference, insulin resistance (assessed by homeostasis model assessment and the quantitative insulin check index), lipid profile and blood pressure values were evaluated. RESULTS: Acromegalic patients and control subjects had similar ApN levels (9.4+/-3.5 vs 9.5+/-4.0 mg/l, NS), while when considering obese subjects acromegalic patients had ApN levels significantly higher than controls (10.2+/-4 vs 7.5+/-3 mg/l, P<0.05). No significant correlation between ApN and GH/IGF-I levels or duration of disease was found. ApN concentrations negatively correlated with BMI, waist circumference, glucose and diastolic blood pressure and positively with high-density lipoprotein cholesterol and ghrelin in controls, while all these correlations were lost in acromegalic patients. CONCLUSIONS: We provide evidence that, although metabolic and cardiovascular abnormalities are present in most acromegalic patients, in these subjects ApN levels are not reduced and, contrary to what is found in BMI-matched controls, do not correlate with cardiovascular risk factors. These data support the view that atherosclerosis is not the main determinant of cardiovascular mortality in acromegaly and suggest a permissive action of GH and/or IGF-I excess on ApN secretion.