A link between sICAM-1, ACE and parietal blood flow in the aging brain.

A connection between Alzheimer's disease (AD) and endothelium pathology has been inferred from measured decreases in both blood flow and metabolism in the parietal and temporal cortex. However, it is not known whether these alterations are seen in normal aging. We performed regional cerebral blood flow (rCBF) measurements in 22 AD patients and in 44 non-demented subjects during a simple test of information processing speed. Cerebrospinal fluid (CSF) levels of angiotensin-converting enzyme (ACE) and the soluble form of intercellular adhesion molecule-1 (sICAM-1) were analyzed in non-demented subjects. We found correlations between sICAM-1 and ACE (p=0.004), and sICAM (but not ACE) and CSF/plasma albumin ratio (p<0.0001). Higher concentrations of sICAM-1 (>893ng/L) and ACE (>5.22microg/L) were exclusively associated with lower parietal blood flow (p<0.001). The rCBF patterns in the AD and non-demented subjects with biomarker levels above median showed similar reductions in the temporoparietal areas. Our findings provide evidence that elevated CSF sICAM-1 and ACE are associated with lower perfusion levels in the parietal cortex of cognitively intact elderly.

Plasma and CSF serpins in Alzheimer disease and dementia with Lewy bodies.

OBJECTIVE: Serine protease inhibitors (serpins), the acute phase reactants and regulators of the proteolytic processing of proteins, have been recognized as potential contributors to the pathogenesis of Alzheimer disease (AD). We measured plasma and CSF levels of serpins in controls and patients with dementia. METHODS: Using rocket immunoelectrophoresis, ELISA, and Luminex xMAP technology, we analyzed plasma levels of alpha(1)-antichymotrypsin and alpha(1)-antitrypsin, and CSF levels of alpha(1)-antichymotrypsin, alpha(1)-antitrypsin, and neuroserpin along with three standard biomarkers (total tau, tau phosphorylated at threonine-181, and the A beta(1-42)) in patients with AD (n = 258), patients with dementia with Lewy bodies (DLB; n = 38), and age-matched controls (n = 37). RESULTS: The level of CSF neuroserpin was significantly higher in AD compared with controls and DLB, whereas CSF alpha(1)-antichymotrypsin and alpha(1)-antitrypsin were significantly higher in both AD and DLB groups than in controls. Results from logistic regression analyses demonstrate a relationship between higher CSF levels of alpha(1)-antichymotrypsin and neuroserpin and increased predicted probability and odds ratios (ORs) of AD (OR 5.3, 95% CI 1.3 to 20.8 and OR 3.3, CI 1.3 to 8.8). Furthermore, a logistic regression model based on CSF alpha(1)-antichymotrypsin, neuroserpin, and A beta(1-42) enabled us to discriminate between AD patients and controls with a sensitivity of 94.7% and a specificity of 77.8%. CONCLUSIONS: Higher CSF levels of neuroserpin and alpha(1)-antichymotrypsin were associated with the clinical diagnosis of Alzheimer disease (AD) and facilitated the diagnostic classification of AD vs controls. CSF serpin levels did not improve the diagnostic classification of AD vs dementia with Lewy bodies.