Non-targeted lipidomics of CSF and frontal cortex grey and white matter in control, mild cognitive impairment, and Alzheimer's disease subjects.

OBJECTIVE: We undertook a non-targeted lipidomics analysis of post-mortem cerebrospinal fluid (CSF), frontal cortex grey matter, and subjacent white matter to define potential biomarkers that distinguish cognitively intact subjects from those with incipient or established dementia. Our objective was to increase our understanding of the role of brain lipids in pathophysiology of aging and age-related cognitive impairment. METHODS: Levels of 650 individual lipids, across 26 lipid subclasses, were measured utilising a high-resolution mass spectrometric analysis platform. RESULTS: Monoacylglycerols (MAG), diacylglycerols (DAG), and the very-long-chain fatty acid 26:0 were elevated in the grey matter of the mild cognitive impairment (MCI) and old dementia (OD) cohorts. Ethanolamine plasmalogens (PlsEtn) were decreased in the grey matter of the young dementia (YD) and OD cohorts while and phosphatidylethanolamines (PtdEth) were lower in the MCI, YD and OD cohorts. In the white matter, decrements in sulphatide levels were detected in the YD group, DAG levels were elevated in the MCI group, and MAG levels were increased in the YD and OD groups. CONCLUSION: The parallel changes in grey matter MAGs and DAGs in the MCI and OD groups suggest that these two cohorts may have a similar underlying pathophysiology; consistent with this, MCI subjects were more similar in age to OD than to YD subjects. While PlsEtn and phosphatidylethanolamine were decreased in the YD and OD groups they were unaltered in the MCI group indicating that alterations in plasmalogen synthesis are unlikely to represent an initiating event in the transition from MCI to dementia.

A translational continuum of model systems for evaluating treatment strategies in Alzheimer's disease: isradipine as a candidate drug.

A growing body of evidence supports the 'calcium hypothesis' of Alzheimer's disease (AD), which postulates that a variety of insults might disrupt the homeostatic regulation of neuronal calcium (Ca(2+)) in the brain, resulting in the progressive symptoms that typify the disease. However, despite ongoing efforts to develop new methods for testing therapeutic compounds that might be beneficial in AD, no single bioassay permits both rapid screening and in vivo validation of candidate drugs that target specific components of the Ca(2+) regulatory machinery. To address this issue, we have integrated four distinct model systems that provide complementary information about a trial compound: the human neuroblastoma MC65 line, which provides an in vitro model of amyloid toxicity; a transgenic Drosophila model, which develops age-dependent pathologies associated with AD; the 3×TgAD transgenic mouse, which recapitulates many of the neuropathological features that typify AD; and the embryonic nervous system of Manduca, which provides a novel in vivo assay for the acute effects of amyloid peptides on neuronal motility. To demonstrate the value of this 'translational suite' of bioassays, we focused on a set of clinically approved dihydropyridines (DHPs), a class of well-defined inhibitors of L-type calcium channels that have been suggested to be neuroprotective in AD. Among the DHPs tested in this study, we found that isradipine reduced the neurotoxic consequences of ß-amyloid accumulation in all four model systems without inducing deleterious side effects. Our results provide new evidence in support of the Ca(2+) hypothesis of AD, and indicate that isradipine represents a promising drug for translation into clinical trials. In addition, these studies also demonstrate that this continuum of bioassays (representing different levels of complexity) provides an effective means of evaluating other candidate compounds that target specific components of the Ca(2+) regulatory machinery and that therefore might be beneficial in the treatment of AD.

Evaluation of coenzyme Q as an antioxidant strategy for Alzheimer's disease.

Increasing evidence suggests that Alzheimer's disease (AD) is associated with oxidative damage that is caused in part by mitochondrial dysfunction. Here we investigated the feasibility of modifying Alzheimer pathology with the mitochondrial antioxidant coenzyme Q (CoQ). Exogenous CoQ protected MC65 neuroblastoma cells from amyloid-beta protein precursor C-terminal fragment (APP CTF)-induced neurotoxicity in a concentration dependent manner, with concentrations of 6.25 microM and higher providing near complete protection. Dietary supplementation with CoQ at a dose of 10 g/kg diet to C65/Bl6 mice for one month significantly suppressed brain protein carbonyl levels, which are markers of oxidative damage. Treatment for one month with 2 g lovastatin/kg diet, which interferes with CoQ synthesis, resulted in a significant lowering of brain CoQ10 levels. Mitochondrial energetics (brain ATP levels and mitochondrial membrane potential) were unaffected by either CoQ or lovastatin treatment. Our results suggest that oral CoQ may be a viable antioxidant strategy for neurodegenerative disease. Our data supports a trial of CoQ in an animal model of AD in order to determine whether a clinical trial is warranted.