Cerebrospinal fluid catecholamines levels in Alzheimer's disease, frontotemporal dementia, and normal controls

Catecholamine analysis and studies to modulate dopamine and norepinephrine in dementia have had contradictory results. We aimed to analyze the cerebrospinal fluid (CSF) levels of L-DOPA, dopamine, and norepinephrine of patients with Alzheimer's disease (AD), frontotemporal dementia (FTD) and normal controls (NC), and their relationship with clinical variables.

Cross-sectional, observational study, to analyze CSF L-DOPA, dopamine, and norepinephrine levels in 35 patients with AD, 16 with FTD, and 38 NC.

L-DOPA was significantly lower in AD than NC (AD vs NC p = 0.039, DFT vs NC p = 0.052, DFT vs DA p = 1.00). Norepinephrine was positively correlated with age (r = 0.343, p = 0.035). Dopamine was higher in participants under antidepressive medication (p = 0.022among all participants; p = 0.046 in NC).

This is the first study reporting lower CSF L-DOPA levels in AD. Similar norepinephrine levels despite locus coeruleus neurons loss in AD point to compensatory mechanisms that could exacerbate L-DOPA deficiency.