Down syndrome (DS,
trisomy 21) is the leading cause of chromosomal-related
intellectual disability. At an early age, adults with DS develop with the neuropathological hallmarks of
Alzheimer's disease, associated with a chronic oxidative stress. To investigate if non-
protein bound
iron (NPBI) can contribute to building up a pro-oxidative microenvironment, we evaluated NPBI in both plasma and erythrocytes from DS and age-matched controls, together with in vivo markers of lipid peroxidation (F2-isoprostanes, F2-dihomo-isoprostanes, F4-neuroprostanes) and in vitro
reactive oxygen species (ROS) formation in erythrocytes. The serum
iron panel and
uric acid were also measured. Second, we explored possible correlation between NPBI, lipid peroxidation and cognitive performance. Here, we report NPBI increase in DS, which correlates with increased serum
ferritin and
uric acid. High levels of lipid peroxidation markers and intraerythrocyte ROS formations were also reported. Furthermore, the scores of Raven's Colored Progressive Matrices (RCPM) test, performed as a measure of current cognitive function, are inversely related to NPBI, serum
uric acid, and
ferritin. Likewise, ROS production,
F2-isoprostanes, and F4-neuroprostanes were also inversely related to cognitive performance, whereas serum
transferrin positively correlated to RCPM scores. Our data reveal that increased availability of free redox-active
iron, associated with enhanced lipid peroxidation, may be involved in neurodegeneration and
cognitive decline in DS. In this respect, we propose
chelation therapy as a potential preventive/therapeutic tool in DS.