PTGS2 and amyloidosis: Since COX-2 expression in the brain and PGE2 content in the cerebrospinal fluid have been reported to be elevated in AD together with the finding that COX-2 protein levels in the brain correlate with the severity of amyloidosis and clinical dementia, it has been suggested that COX-2 inhibition by NSAIDs might be involved in the apparent protection in this setting.