Introduction: The locus coeruleus is the primary site of norepinephrine (NE) synthesis in the brain. Its dysfunction has been implicated in the pathogenesis of Alzheimer’s disease. Vascular risk factors, thyroid dysfunction, and vitamin deficiencies have also been associated with an increased risk of dementia. This study aimed to evaluate the relationship between the catecholaminergic system-by measuring cerebrospinal fluid (CSF) levels of L-3,4-dihydroxyphenylalanine (L-DOPA), dopamine (DA), and NE-and vascular risk factors, thyroid dysfunction, and vitamin deficiencies. Methods: We conducted a cross-sectional observational study in which CSF levels of L-DOPA, DA and NE were measured in 117 participants. Data on Blood Pressure (BP), heart rate, glycaemic and lipid profiles, smoking history, thyroid function and vitamin B12 and folic acid levels were collected for each participant. Results: We found significant correlations between NE and CSF glucose levels (r = 0.308, p = 0.003) in participants without diabetes mellitus, between L-DOPA and orthostatic variation of diastolic BP (r = -0.288, p = 0.014) and high-density lipoprotein (r = 0.404, p = 0.001) and between NE and triglycerides (r = 0.271, p = 0.030) and folic acid (r = 0.298, p = 0.009). Discussion: This is the first study to demonstrate correlations between CSF NE levels and CSF glucose, probably due to the effect of NE on astrocytes, and between CSF NE levels and folic acid, possibly related to its role in catecholamine synthesis. CSF L-DOPA levels were correlated with cardiovascular risk factors such as the orthostatic regulation of diastolic BP. Conclusion: These findings may contribute to a better understanding of the pathophysiology of neurodegenerative diseases.
Moreira et al. (Fri,) studied this question.