Abstract
Acromegaly is characterized by high cardiovascular morbidity and mortality. Oxidative
stress and endothelial dysfunction are underlying mechanisms of atherosclerosis.The
aim of this study was to evaluate the blood redox status and endothelial function
by means of nitric oxide (NO) levels in patients with acromegaly. Total antioxidant
capacity (TAC), catalase activity and glutathione concentration (GSH), as measures
of antioxidative capacity, total oxidized glutathione (GSSG) and thiobarbituric acid
reactive substances (TBARS), as indices of oxidative stress, and NO levels were assessed
in 15 patients with acromegaly (age 55.4±10.5 years; 6 males) and 15 age- and sex-matched
controls (age 58.4±8.1 years; 7 males). Active disease was present in 12 patients:
11 on current pharmacotherapy and 1 newly diagnosed. Three acromegalics were in remission
after successful treatment. Acromegalics as compared with controls had significantly
lower levels of catalase activity (8.2±5.8 vs. 51.3±29.1 mmol/ml/min, p<0.001), GSH
(0.97±0.54 vs. 1.41±0.35 mmol/l, p=0.006), GSSG (0.27±0.19 vs. 2.04±1.32 mmol/l, p=0.002)
and NO levels (6.0±3.1 vs. 43.0±29.8 mmol/l, p<0.001), but higher TBARS (16.3±8.9
vs. 10.1±10.8, nmol/ml, p=0.019). After adjustment for confounders, differences in
catalase activity, NO levels and TBARS remained significant (p=0.004, p<0.001 and
p=0.025, respectively). No association between IGF-I/GH and oxidative stress markers
was noticed, except for a positive correlation between nadir GH and GSSG (r2=0.563, p=0.036). Acromegaly is associated with increased levels of oxidative stress
coupled by diminished antioxidant capacity and endothelial dysfunction indicated by
the presence of decreased NO levels.
Key words
acromegaly - oxidative stress - total antioxidant capacity - catalase - glutathione
- nitric oxide
