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Colocalization of ODC and Amyloid Plaques in AD/DS Patients

Polyamines, and their rate limiting enzyme ornithine decarboxylase (ODC), are crucial for many functions in the central nervous system but levels decrease with age. In neurodegenerative diseases, like Alzheimer’s Disease (AD), polyamine levels begin to increase again. Yet, there are still many unanswered questions surrounding polyamine’s possible role in AD. Polyamine levels are especially heightened in people with Down Syndrome (DS), who also have an extra copy of the amyloid precursor protein (APP), and tend to get AD far earlier than the general population.

We aim to see if there is colocalization between amyloid plaques and ODC in patients with AD and DS, in order to see if there is a relationship between the two, and if this could be a pathway of neurotoxicity in AD that underlies its pathogenesis. This will be done through immunofluorescence staining of paraffin-embedded human hippocampal tissue from control, AD, and AD/DS patients for ODC, β-amyloid, and collagen for vascularity. Preliminary results indicate some colocalization of ODC and amyloid plaques that tend to be located near vascularity, and that this colocalization is increased in those with DS and AD. This suggests that there is a relationship between ODC and amyloid plaques, although the directionality is unknown, and that this could indicate an underlying pathway contributing to AD pathogenesis.