Serum lipid resistance to oxidation and uric acid levels in subjects with Down's syndrome

In subjects with Down's syndrome (DS) increased oxidative stress and conseq uent oxidative cell damage have been reported. The aim of this study was to assess whether the excessive production of free oxygen radicals in these s ubjects can affect the copper-induced lipid oxidation resistance measured i n fresh whole serum. Since a significant elevation of serum uric acid level s, which is an efficient hydrophilic antioxidant, has been repeatedly repor ted in subjects with DS, we studied the association between increased serum uric acid levels and lipid resistance to oxidation measured directly in se rum samples by monitoring the change in absorbance at 234 nm. The group of subjects with Down's syndrome consisted of 25 individuals (aged 18+/-5 year s). Control group included brothers and sisters of subjects with DS (n = 25 , aged 17+/-7 years). In subjects with DS, the serum lipid resistance to ox idation (lag time) was significantly higher than in controls (p<0.05) and a concomitant increase in serum uric acid levels was observed (p<0.001). A s ignificant positive correlation between lag time and serum uric acid concen tration was found in subjects with DS (r = 0.48, p<0.05), while the positiv e correlation ill the control group was not significant. The results sugges t that increased serum uric acid levels repeatedly observed in subjects wit h DS may be associated with an enhanced resistance of serum lipids to oxida tion which is thought to play an important role in the atherogenic process.