Down syndrome with Alzheimer's disease brains have increased iron and associated lipid peroxidation consistent with...

Area of Science:

• Neuroscience
• Biochemistry
• Genetics

Background:

• Cerebral microbleeds (MB) are linked to Alzheimer's Disease (AD) and Down Syndrome with AD (DSAD).
• Iron accumulation in MB may drive lipid peroxidation and neurodegeneration.
• Amyloid precursor protein (APP) triplication in DSAD might exacerbate iron load and oxidative stress.

Purpose of the Study:

• Investigate the relationship between amyloid deposition, iron load, and lipid peroxidation in AD and DSAD.
• Examine proteins involved in iron metabolism, antioxidant response, and amyloid processing.

Main Methods:

• Analyzed prefrontal cortex and cerebellum from cognitively normal (CTL), AD, and DSAD individuals (ApoE3,3 carriers).
• Assessed proteins mediating iron metabolism, antioxidant defense, and amyloid processing within lipid rafts.

Main Results:

• DSAD exhibited a 2-fold increase in iron compared to CTL and AD.
• Increased iron storage proteins and lipid peroxidation were observed in the prefrontal cortex of DSAD and AD.
• Glutathione synthesis protein GCLM decreased by 50% in both AD and DSAD.
• Lipid raft-associated glutathione peroxidase 4 (GPx4) activity decreased by at least 30% in AD and DSAD.

Conclusions:

• DSAD demonstrates more severe lipid peroxidation than AD, correlating with higher microbleed and iron burden.
• These findings highlight the role of iron dysregulation and oxidative stress in the pathogenesis of DSAD.