Markers of oxidative stress in children with Down syndrome

Background: Persons with Down syndrome have increased vulnerability to oxidative stress caused by overexpression of superoxide dismutase, an antioxidant enzyme coded on chromosome 21. Increased oxidative stress may lead to oxidative damage of important macromolecules. We monitored this damage by measuring levels of different biomarkers of oxidative stress ( protein carbonyls and 4-hydroxy-2-nonenal), as well as plasma antioxidant capacity, in children with Down syndrome. A total of 20 children with Down syndrome and 18 healthy individuals were recruited for this purpose. Methods: Plasma protein carbonyls were measured using an ELISA technique, 4-hydroxy-2-nonenal was monitored by HPLC and the antioxidant capacity was evaluated using a ferric reducing ability of plasma ( FRAP) assay. Results: We found that children with Down syndrome had significantly elevated levels of protein carbonyls compared to healthy controls (p< 0.01). Levels of 4-hydroxy-2- nonenal and antioxidant capacity were similar in both groups. Conclusion: Our results on oxidative damage to proteins confirm the assumption of increased oxidative stress in individuals with Down syndrome.