Altered inflammation, paraoxonase-1 activity and HDL physicochemical properties in obese humans with and without Prader-Willi syndrome.

Prader-Willi syndrome (PWS) represents the most common form of genetic obesity. Several studies confirm that obesity is associated with inflammation, oxidative stress and impairment of antioxidant systems; however, no data are available concerning PWS subjects. We compared levels of plasma lipids and C-reactive protein (CRP) in 30 subjects of 'normal' weight (18.5-25 kg/m(2)), 15 PWS obese (>30 kg/m(2)) subjects and 13 body mass index (BMI)-matched obese subjects not affected by PWS. In all subjects, we evaluated the levels of lipid hydroperoxides and the activity of paraoxonase-1 (PON1), an enzyme involved in the antioxidant and anti-inflammatory properties exerted by high-density lipoproteins (HDLs). Furthermore, using the fluorescent molecule of Laurdan, we investigated the physicochemical properties of HDLs isolated from normal weight and obese individuals. Altogether, our results demonstrated, for the first time, higher levels of lipid hydroperoxides and a lower PON1 activity in plasma of obese individuals with PWS with respect to normal-weight controls. These alterations are related to CRP levels, with a lower PON1:CRP ratio in PWS compared with non-PWS obese subjects. The study of Laurdan fluorescence parameters showed significant modifications of physicochemical properties in HDLs from PWS individuals. Whatever the cause of obesity, the increase of adiposity is associated with inflammation, oxidative stress and alterations in HDL compositional and functional properties.