Calcitonin gene-related peptide and calcitonin in the CSF of patients with dementia and depression -: Possible disease markers

Cerebrospinal fluid (CSF) was obtained from 32 patients with dementia, 19 healthy controls that were age-matched with the dementia patients, and 29 DSM-IV major depression patients and calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) and calcitonin-like immunoreactivity (CT-LI) measured by RIA. CGRP-LI was lower in the dementia group compared to both the controls and depressed patients (P < .01) after covarying out sex and age. CT-LI was decreased in the dementia and depressed patients (P < .05) compared to the controls, A positive relationship between CGRP-LI and CT-LI was found in dementia. A logistic discriminant analysis with calcitonin gene-related peptide (CGRP) and log calcitonin (CT) predicting diagnosis (three classes) revealed a significant overall fit (chi (2) = 18.08, P= .0011), with an effect test showing contributions of both independent variables: CGRP (chi (2) = 10.03, P < .007), log CT (chi (2) = 8.63, P= .013). In dementia, both CGRP-LI and CT-LI were decreased and their concentration ratio did not differ from that in controls, likely reflecting a general neuronal loss. Alternatively and more speculatively, but theoretically possible, expression of the alpha -CGRP/CT gene may be affected in dementia. In contrast, in depression, CT-LI but not CGRP-LI was decreased and the CGRP/CT concentration ratio was increased, which is consistent with a possibility of an altered splicing process favoring CGRP mRNA. (C) 2001 Elsevier Science Inc. All rights reserved.