P3-091

S400

Poster P3:: Tuesday Posters

jects clinically defined as controls or with other neurological diseases, 7 patients with mild cognitive impairment, 9 with dementia with Lewy bodies, and 11 with Alzheimer’s disease. Results and Conclusions: Amino-terminally truncated species were abundantly present, not only in all clinically defined AD cases, but also in the preclinical stages in brain regions with the earliest neuropathologically detectable signs of Alzheimer’s disease. Based on the immunocapture mass spectrometry data, the earliest species of amino-terminally truncated species are full-size, Ntruncated 4 (a potential nephrylisin proteolytic cleavage site), and Ntruncated 8 amyloid (a potential angiotensin-converting enzyme cleavage site). Amino-terminal truncation is closely associated with amyloid plaque deposition and with no obvious difference between plaque formation in Alzheimer’s disease or in dementia with Lewy bodies. Ongoing studies on the presence of these N-truncated amyloid beta species in cerebrospinal fluid and blood plasma will be presented. P3-091

NEUROPROTEOMICS IN ALZHEIMER’S DISEASE: EXPRESSION PROFILING OF THE BRAIN PROTEOMES AND THEIR RELATION TO PROTEOMES OF BODY FLUIDS

Teruyuki Tsuji1, Jun Kawamata1, Kengo Uemura2, Katsuya Okawa2, Ippou Hirayoshi3, Shun Shimohama1, 1Kyoto University Graduate School of Medicine, Kyoto, Japan; 2HMRO Kyoto University Graduate School of Medicine, Kyoto, Japan; 3Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan. Contact e-mail: [email protected] Background: Rapidly progressing proteomics techniques have been widely adopted in most areas of biology and medicine. One of the distinct advantages of proteomic analysis, not attainable with RNA expression data, is the ability to fractionate the cell’s proteins into various subpopulations. In neurology and neuroscience, many applications have been entertained in neurotoxicology and neurometabolism, and used in the determination of specific proteomic aspects of individual brain areas and body fluids in neurodegeneration to identify biomarkers. Objective(s): Investigation of brain protein groups in neurodegeneration, such as enzymes, cytoskeleton proteins, chaperones, synaptosomal proteins and antioxidant proteins, is in progress as phenotype related proteomics. The concomitant detection of several hundred proteins on a gel provides sufficiently comprehensive data to determine a pathophysiological protein network and its peripheral representatives. Methods: The rapid spread of proteomics technology, which principally consists of two-dimensional gel electrophoresis (2-DE) with in-gel protein digestion of protein spots and identification by mass-spectrometry, has provided an explosive amount of results. In this study, quantitative proteome analysis of AD brains was performed using two-dimensional (2-D) gels. For the higher resolution of 2-DE including the detailed analysis of hydrophobic proteins, we sequentially extracted brain protein. Results: The identified proteins thus examined include enzymes, heat shock proteins and cell structure proteins. We also examined body fluids proteomes to determine the same proteins as in brain proteome using two-dimensional difference gel electrophoresis (2D-DIGE). Conclusions: In neuroscience, ‘neuroproteomics’ (proteomics in the central nervous system) is still in its infancy, with a paucity of studies in the context of the brain. There are several other analytical problems which also need to be overcome, and once solved, will allow for a more comprehensive analysis of the individual disease process. P3-092

AMYLOID BETA LEVELS IN PLASMA AND CSF ARE CORRELATED IN HEALTHY INDIVIDUALS

Vilmantas Giedraitis1, Nina Gårevik1, Johan Sundelo¨f1, Michael C. Irizarry2, Martin Ingelsson1, Lars Lannfelt1, 1Uppsala University, Uppsala, Sweden; 2Massachusetts General Hospital, Boston, MA, USA. Contact e-mail: [email protected] Background: CSF levels of A␤42 are consistently lower in patients with Alzheimer’s disease (AD) than in non-demented individuals. Animal and

human studies indicate that A␤ can pass between the CSF and plasma compartments. CSF A␤ levels do not correlate with plasma A␤ levels in patients with AD, whereas the relation between CSF and plasma levels of A␤ in cognitively intact individuals has not been reported. Objective: To investigate the relationship between plasma and CSF A␤40 and A␤42 levels in normal controls and in patients with AD and mild cognitive impairment (MCI). Methods: A␤40 and A␤42 levels were analyzed by ELISA in both CSF and plasma, in 39 patients with Alzheimer’s disease, 29 patients with MCI and 18 healthy controls. Results: In agreement with previous studies, there was a significant decrease of A␤42 in CSF of AD patients when compared to individuals with MCI and healthy controls (p⬍0.001). Carriers of the APOE ⑀4 allele had a lower A␤42/A␤40 ratio in CSF. This was statistically significant in individuals with MCI (p⫽0.03) as well as in all individuals analyzed together (p⫽0.002). No differences in plasma levels of A␤40 and A␤42 were observed among the diagnoses. Surprisingly, we observed a moderate correlation between plasma and CSF levels of A␤40 (r ⫽ 0.52) and A␤42 (r ⫽ 0.48) in healthy controls, but not in MCI or AD patients. Moreover, within plasma and within CSF, A␤40 levels significantly correlated with A␤42 levels. Correlation between A␤40 and A␤42 in plasma was strongest in healthy controls (r ⫽ 0.68) and weakest in AD patients (r ⫽ 0.25), whereas in CSF similar correlations were observed in all three groups (r ⫽ 0.66-0.72). Conclusion: Taken together, these observations suggest that the normal equilibrium between plasma and CSF A␤ is disrupted when amyloid deposition occurs in the AD brain, and reinforces plasma A␤ as a physiologically relevant biomarker. P3-093

PERIPHERAL BIOMARKERS IN ALZHEIMER’S DISEASE: A NOVEL PROTEOMICNEUROIMAGING APPROACH

Madhav Thambisetty1, Abdul Hye1, Catherine Foy1, James Campbell2, Steven Lynham1, Malcolm Ward3, Eileen Daly4, Michaela Poppe1, Nicola Archer1, Andrew Simmons5, Declan Murphy6, Simon Lovestone1, 1MRC Centre for Neurodegeneration Research, Institute of Psychiatry, London, United Kingdom; 2Proteome Sciences Plc, Institute of Psychiatry, Cobham, United Kingdom; 3Proteome Sciences Plc, Institute of Psychiatry, London, United Kingdom; 4Section of Brain Maturation, Department of Psychological Medicine, Institute of Psychiatry, London, United Kingdom; 5Neuroimaging Research Group, Department of Neurology, Institute of Psychiatry, London, United Kingdom; 6Section of Brain Maturation, Institute of Psychiatry, London, United Kingdom. Contact e-mail: [email protected] Background: The emergence of disease-modifying treatments for Alzheimer’s disease (AD) has increased the need for valid biomarkers in the condition. It is likely that novel therapies will be efficacious when targeted at patients in early stages of the disease. Objective(s): To use a combined proteomic and neuroimaging approach for the identification of plasma biomarkers in AD. Methods: Two dimensional gel electrophoresis (2DGE) was performed on plasma samples in a cohort of AD (n⫽18), mild cognitive impairment (n⫽13) and age-matched, healthy controls (n⫽14). Subjects underwent 1H-magnetic resonance spectroscopy (MRS) of the brain to derive estimates of N-acetyl aspartate (NAA), myo-inositol (mI), choline (Cho) and creatine⫹phosphocreatine (Cr⫹PCr). Silver-stained protein spots visualised in the 2DGE gels were edited using MELANIE-3 software. Spots were matched to a reference synthetic gel generated earlier in our laboratory from 2DGE on AD (n⫽50) and control (n⫽50) plasma. After identifying the 14 plasma protein spots previously observed to be significantly different in AD versus control subjects, we examined their correlations to various hippocampal metabolite ratios. Partial correlation analyses were performed after controlling for hippocampal grey matter volume and without correcting for multiple comparisons. Results: Of the 14 plasma protein spots previously observed to be significantly different in AD plasma, we successfully matched a majority (8/14) in at least 50% of the gels in the current study. We observed modest positive correlations between spot-1 (alpha2-macroglobulin; r⫽ 0.36, p⬍0.02) and spot-2 (com-