Neurochemical differences in the CSF between Binswanger's and Alzheimer's disease

In 21 patients suffering from Binswanger's disease (BD) and in 53 patients suffering from Alzheimer's disease, we measured cerebrospinal fluid (CSF) concentrations of somatostatin-like immunoreactivity (SLI), high molecular weight form somatostatin (HMV-SST), somatostatin-25/28 (SST-25/28), somatostatin-14 (SST-14), Des-ala-somatostatin (Des-ala-SST), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA). The patients were classified into three stages of intellectual deterioration according to the global deterioration scale (GDS). Levels of SLI were significantly decreased in BD in general and in SDAT patients with severe dementia (GDS 7), compared to a control group (BD overall 19.7 +/- 11.6 fmol/ml, SDAT 18.6 +/- 7.9 vs. 30.5 +/- 8.6 fmol/ml in controls, p < 0.01 for both). In SDAT patients, SLI levels correlated with dementia scores (r = -0.65, p < 0.05), but not in BD. HVA levels were decreased significantly in SDAT and BD patients with severe dementia (SDAT 273.5 +/- 138.7, BD 224.3 +/- 69.9 vs. 364.9 +/- 103.8 nmol/ml, p < 0.01 in controls, p < 0.05 for both). In BD patients with light dementia (GDS 2-4), HVA levels were significantly elevated (p < 0.05). In BD, HVA levels correlated with dementia (r = -0.59, p < 0.01). 5-HIAA was significantly elevated in BD patients with light dementia (p < 0.05). Qualitative and quantitative changes in the molecular forms of SLI are compatible with a dysregulated posttranslational processing SDAT and BD. We also observed significant correlations between SLI, 5-HIAA and HVA in BD indicating a neurochemical heterogeneous and generalized process affecting several transmitter systems and functions. In summary, our study shows that despite their quite different neuropathology, SDAT and BD do not differ fundamentally in their neurochemical profile.