Evaluation of adiponectin and visfatin levels in serum and exhaled breath condensate in SAS obese patients

Objectives: Obesity is associated with alterated adipocytokine concentrations, in paticular adiponectin and visfatin. Aim of our study was to determine serum and exhaled breath condensate (EBC) levels of adiponectin and visfatin in 13 SAS patients with severe obesity, without metabolic syndrome. Materials and methods: All patients were evaluated by physical examination, medical history, biochemical parameters, spirometric test, chest X-ray, Blood gas analysis, Epworth sleepiness scale, an in-house questionnaire for SAS risk and full polisomnography (Compumedic Sydney). All patients performed EBC, a non-invasive method to collect the exhaled air (reflecting lining fluid) through a frozen ecoscreen condensing chamber (R-Tube, Cosmed Italy). Adiponectin and visfatin levels were measured in plasma and EBC by ELISA kit (B-Bridge International. Inc. San Josè USA). The sensitivity of the assay was 0.37 mcg/ml for adiponectin and 0.1 ng/ml for visfatin; interassays CV range: 5–7%. Ten healthy, non-smoker, non-obese, non-snoring, non-SAS subjects formed the control group. Results: Gender Age (year old) BMI (kg/m2) AHI (events/h) SAS Nine males 53.17 ± 13.38 36.64 ± 11.95 52.32 ± 27.99 Normal Five males 32.57 ± 5.32 19.84 ± 2.13 <5 Serum adiponectin* Serum visfatin+ EBC adiponectin* EBC visfatin+ SAS 6.51 ± 5.15 10.98 ± 2.90 Non-detectable 2.33 ± 0.76 Normal 13.20 ± 2.67 7.53 ± 1.89 Non-detectable 1.955 ± 1.44 * = mcg/ml; + = ng/ml. Serum adiponectin p = 0.001. Serum visfatin p = 0.01. EBC visfatin p = 0.61 (detectable in 50% of subjects). Conclusions: Serum adiponectin levels are significantly lower in SAS patients than in normal, and non-detectable in EBC samples. On the other hand, visfatin concentration is significantly higher in serum of SAS subjects, but not in EBC (when detectable). This is probably due to different tissue distribution of these substances. Further studies are needed to evaluate whether SAS is an independent factor regarding alterated production of these adipocytokines.