- Email: [email protected]
High-molecular weight β-amyloid oligomers are elevated in cerebrospinal fluid of Alzheimer patients
Poster Presentations P3
S512 P3-208
TOTAL ANTIOXIDANT STATUS IN NEWLY DIAGNOSED ALZHEIMER’S PATIENTS: POPULATION BASED STUDY
Katarzyna A. Gustaw-Rothenberg1,2, Sandra L. Siedlak3, George Perry4,3, Alan Lerner2, Mark A. Smith3, 1IMW, Lublin, Poland; 2Memory and Cognition Center, Neurological Institute, UHCMC, Cleveland, OH, USA; 3 Department of Pathology, Case Western Reserve University, Cleveland, OH, USA; 4UTSA Neurosciences Institute and Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA. Contact e-mail: [email protected] Background: Oxidative imbalance appears to both directly and indirectly play a major role in cellular processes implicated in neurodegeneration and Alzheimer’s disease pathology. Free radical production results in oxidative damage to a range of biomolecules which are implicated in AD development. In this study we investigated a facet of oxidative stress in a group of AD patients from a population-based sample. Methods: 52 AD subjects recruited from the population-based study as well as 27 age and gender matched control patients were examined. The examined group was stratified according to the neurodegenerative process length (i.e., time from diagnosis). Serum total antioxidant status (TAS) was determined as a quantitative assessment of in vivo oxidative status Results: Serum total antioxidant status was calculated for samples from each study group. TAS levels were significantly decreased in AD subjects as compared to control (0.6 vs 1.39 mmol/L, P <0.001). The most pronounced differences in TAS levels were apparent in the AD group with the shortest history of the disease (the time from diagnosis). TAS was significantly lower in newly diagnosed AD patients when compared to controls. Conclusions: These results strengthen the hypothesis that oxidative dyshomeostasis is an early and disease-specific phenomenon in AD development. Targeting oxidative stress and increasing antioxidant capacity of affected individuals, especially at the earliest possible time after symptoms appear, may be most beneficial. P3-209
ASSOCIATIONS BETWEEN GONADOTROPINS, TESTOSTERONE, PLASMA Ab AND PIB RETENTION IN MEN WITH SUBJECTIVE MEMORY COMPLAINTS OR MILD COGNITIVE IMPAIRMENT
Simon M. Laws1,2, Giuseppe Verdile1,2, David Ames3,4, Ashley I. Bush5,6, Kathryn A. Ellis3,4, Veer Gupta1,2, James K. Lui1,2, Colin L. Masters5,7, Christopher C. Rowe8, Cassandra Szoeke4,9, Kevin Taddei1,2, Victor L. Villemagne5,8, Ralph N. Martins1,2 the AIBL Research Group1Centre of Excellence for Alzheimer’s Disease Research & Care, School of Exercise Biomedical and Health Sciences, Edith Cowan University, Joondalup, Australia; 2Sir James McCusker Alzheimer’s Disease Research Unit, Hollywood Private Hospital, Perth, Australia; 3Academic Unit for Psychiatry of Old Age, Department of Psychiatry, The University of Melbourne, St. Vincent’s Aged Psychiatry Service, St. George’s Hospital, Melbourne, Australia; 4National Ageing Research Institute, Parkville, Australia; 5Mental Health Research Institute, The University of Melbourne, Parkville, Australia; 6Department of Pathology, The University of Melbourne, Melbourne, Australia; 7Centre for Neuroscience, The University of Melbourne, Parkville, Australia; 8Department of Nuclear Medicine & Centre for PET, Austin Health, Heidelberg, Australia; 9CSIRO, Parkville, Australia. Contact e-mail: [email protected] Background: Low levels of testosterone and high levels of gonadotropins have been associated with cognitive decline in dementia cases in men. Studies have shown that these hormones can modulate Ab metabolism, contributing to Alzheimer’s disease (AD) pathogenesis. However, there are relatively few studies that have determined if changes in one or a combination of these hormones can influence Ab levels in elderly men or those with dementia, those that have, focused on plasma Ab40 levels. Recently, it has become apparent that the plasma Ab1-42/1-40 ratio rather than absolute levels of these peptides are better indicators of AD risk. Further, no study to date has investigated whether these hormones are associated with increases in brain amyloid deposition, ante mortem. Methods: Through the use of the highly characterised Australian Imaging, Biomarkers and Lifestyle study, we have determined the
impact of testosterone and gonadotropins on plasma Ab1-42/1-40 ratio and also amyloid deposition through Pittsburgh compound B (PiB) retention. The cohort is divided into three clinical classifications; healthy controls (including non and subjective memory complainers (SMC)) and individuals with either mild cognitive impairment (MCI) or AD. Results: Spearman’s rank correlation analysis and linear regression analysis was carried out within each respective clinical classification. Increased age and reductions in calculated free testosterone (cFT) were the only variables, shown to significantly impact on plasma Ab1-42/1-40 ratio and this only occurred in the SMC group. In the SMC group increased frequency of the APOE-e4 allele and increasing serum luteinizing hormone (LH) levels significantly impacted on PiB retention. Whilst in the MCI group, PiB retention was associated with increased copy number of the APOE-e4 allele and decreasing cFT. In AD these associations were not observed. Conclusions: Our results indicate that hormonal levels, particularly LH and testosterone, may be of value when attempting to predict AD in very early stages of the disease, in particular when used in conjunction with other known risk factors/biomarkers (established or candidate) of AD. P3-210
HIGH-MOLECULAR WEIGHT b-AMYLOID OLIGOMERS ARE ELEVATED IN CEREBROSPINAL FLUID OF ALZHEIMER PATIENTS
Takahiko Tokuda1, Hiroaki Fukumoto2, Takashi Kasai1, Noriko Ishigami1, Masaki Kondo1, Masanori Nakagawa1, 1Kyoto Prefectural University of Medicine, Kyoto, Japan; 2Takeda Pharmaceutical Co., Ltd., Pharmacology Research Division, Osaka, Japan. Contact e-mail: ttokuda@ koto.kpu-m.ac.jp Background: Biomarkers to diagnose Alzheimer’s disease (AD) at a very early stage and to monitor responses of patients to upcoming disease-modifying treatments are urgently needed. There are accumulating reports that soluble Ab oligomers, rather than amyloid fibrils, are the principal pathogenic species in AD. However, there is still no consensus on what species of Ab oligomers in the brains of AD patients is most toxic, and widely available assays to quantify such Ab oligomers are needed. Methods: We developed a novel enzyme-linked immunosorbent assay (ELISA) specific for high-molecular weight (HMW) Ab oligomers using the same amino-terminal Ab antibody for both antigen capture and detection (BAN50-BAN50 ELISA) and determined the levels of HMW Ab oligomers together with monomeric Ab species, Abx-40 (Ab40) and Abx-42 (Ab42) in the same samples of cerebrospinal fluid (CSF) from 18 patients with clinically diagnosed AD, 7 patients with mild cognitive impairment who later converted to AD (MCI-C) and 25 age-matched control subjects. Results: The size-exclusion chromatography (SEC) analysis of Ab oligomers made from synthetic Ab1-42 revealed that our ELISA specifically detected HMW Ab oligomers of 40-200 kDa without detection of monomers and low-molecular weight oligomers (dimers, trimers, tetramers and hexamers). Using this ELISA, we detected significantly higher (p < 0.0001) signals in CSFs from 25 patients with AD or mild cognitive impairment (MCI) compared with 25 age-matched controls. The area under the curve in the receiver operating characteristic analysis for the CSF HMW Ab oligomers was greater than that for the CSF Abx-42 in the discrimination between the AD/MCI and control groups. Furthermore, the CSF levels of HMW Ab oligomers showed a negative correlation with Mini-Mental State Examination scores in the AD/MCI group. Conclusions: We conclude that the CSF HMW Ab oligomers detected by our ELISA could be useful as a diagnostic marker for AD, and also as a potential surrogate marker for the disease severity. Our results support the idea that soluble HMW Ab oligomers play a critical role in the pathogenesis and progression of AD. P3-211
BUCCAL MICRONUCLEUS CYTOME BIOMARKERS MAY BE ASSOCIATED WITH ALZHEIMER’S DISEASE
Michael Fenech, Philip Thomas, CSIRO, Adelaide, Australia. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is a progressive degenerative disorder of the brain and is the commonest form of dementia. We tested the hypothesis that buccal mucosa in AD reflect aspects of reduced regenerative potential such
S512 P3-208
TOTAL ANTIOXIDANT STATUS IN NEWLY DIAGNOSED ALZHEIMER’S PATIENTS: POPULATION BASED STUDY
Katarzyna A. Gustaw-Rothenberg1,2, Sandra L. Siedlak3, George Perry4,3, Alan Lerner2, Mark A. Smith3, 1IMW, Lublin, Poland; 2Memory and Cognition Center, Neurological Institute, UHCMC, Cleveland, OH, USA; 3 Department of Pathology, Case Western Reserve University, Cleveland, OH, USA; 4UTSA Neurosciences Institute and Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA. Contact e-mail: [email protected] Background: Oxidative imbalance appears to both directly and indirectly play a major role in cellular processes implicated in neurodegeneration and Alzheimer’s disease pathology. Free radical production results in oxidative damage to a range of biomolecules which are implicated in AD development. In this study we investigated a facet of oxidative stress in a group of AD patients from a population-based sample. Methods: 52 AD subjects recruited from the population-based study as well as 27 age and gender matched control patients were examined. The examined group was stratified according to the neurodegenerative process length (i.e., time from diagnosis). Serum total antioxidant status (TAS) was determined as a quantitative assessment of in vivo oxidative status Results: Serum total antioxidant status was calculated for samples from each study group. TAS levels were significantly decreased in AD subjects as compared to control (0.6 vs 1.39 mmol/L, P <0.001). The most pronounced differences in TAS levels were apparent in the AD group with the shortest history of the disease (the time from diagnosis). TAS was significantly lower in newly diagnosed AD patients when compared to controls. Conclusions: These results strengthen the hypothesis that oxidative dyshomeostasis is an early and disease-specific phenomenon in AD development. Targeting oxidative stress and increasing antioxidant capacity of affected individuals, especially at the earliest possible time after symptoms appear, may be most beneficial. P3-209
ASSOCIATIONS BETWEEN GONADOTROPINS, TESTOSTERONE, PLASMA Ab AND PIB RETENTION IN MEN WITH SUBJECTIVE MEMORY COMPLAINTS OR MILD COGNITIVE IMPAIRMENT
Simon M. Laws1,2, Giuseppe Verdile1,2, David Ames3,4, Ashley I. Bush5,6, Kathryn A. Ellis3,4, Veer Gupta1,2, James K. Lui1,2, Colin L. Masters5,7, Christopher C. Rowe8, Cassandra Szoeke4,9, Kevin Taddei1,2, Victor L. Villemagne5,8, Ralph N. Martins1,2 the AIBL Research Group1Centre of Excellence for Alzheimer’s Disease Research & Care, School of Exercise Biomedical and Health Sciences, Edith Cowan University, Joondalup, Australia; 2Sir James McCusker Alzheimer’s Disease Research Unit, Hollywood Private Hospital, Perth, Australia; 3Academic Unit for Psychiatry of Old Age, Department of Psychiatry, The University of Melbourne, St. Vincent’s Aged Psychiatry Service, St. George’s Hospital, Melbourne, Australia; 4National Ageing Research Institute, Parkville, Australia; 5Mental Health Research Institute, The University of Melbourne, Parkville, Australia; 6Department of Pathology, The University of Melbourne, Melbourne, Australia; 7Centre for Neuroscience, The University of Melbourne, Parkville, Australia; 8Department of Nuclear Medicine & Centre for PET, Austin Health, Heidelberg, Australia; 9CSIRO, Parkville, Australia. Contact e-mail: [email protected] Background: Low levels of testosterone and high levels of gonadotropins have been associated with cognitive decline in dementia cases in men. Studies have shown that these hormones can modulate Ab metabolism, contributing to Alzheimer’s disease (AD) pathogenesis. However, there are relatively few studies that have determined if changes in one or a combination of these hormones can influence Ab levels in elderly men or those with dementia, those that have, focused on plasma Ab40 levels. Recently, it has become apparent that the plasma Ab1-42/1-40 ratio rather than absolute levels of these peptides are better indicators of AD risk. Further, no study to date has investigated whether these hormones are associated with increases in brain amyloid deposition, ante mortem. Methods: Through the use of the highly characterised Australian Imaging, Biomarkers and Lifestyle study, we have determined the
impact of testosterone and gonadotropins on plasma Ab1-42/1-40 ratio and also amyloid deposition through Pittsburgh compound B (PiB) retention. The cohort is divided into three clinical classifications; healthy controls (including non and subjective memory complainers (SMC)) and individuals with either mild cognitive impairment (MCI) or AD. Results: Spearman’s rank correlation analysis and linear regression analysis was carried out within each respective clinical classification. Increased age and reductions in calculated free testosterone (cFT) were the only variables, shown to significantly impact on plasma Ab1-42/1-40 ratio and this only occurred in the SMC group. In the SMC group increased frequency of the APOE-e4 allele and increasing serum luteinizing hormone (LH) levels significantly impacted on PiB retention. Whilst in the MCI group, PiB retention was associated with increased copy number of the APOE-e4 allele and decreasing cFT. In AD these associations were not observed. Conclusions: Our results indicate that hormonal levels, particularly LH and testosterone, may be of value when attempting to predict AD in very early stages of the disease, in particular when used in conjunction with other known risk factors/biomarkers (established or candidate) of AD. P3-210
HIGH-MOLECULAR WEIGHT b-AMYLOID OLIGOMERS ARE ELEVATED IN CEREBROSPINAL FLUID OF ALZHEIMER PATIENTS
Takahiko Tokuda1, Hiroaki Fukumoto2, Takashi Kasai1, Noriko Ishigami1, Masaki Kondo1, Masanori Nakagawa1, 1Kyoto Prefectural University of Medicine, Kyoto, Japan; 2Takeda Pharmaceutical Co., Ltd., Pharmacology Research Division, Osaka, Japan. Contact e-mail: ttokuda@ koto.kpu-m.ac.jp Background: Biomarkers to diagnose Alzheimer’s disease (AD) at a very early stage and to monitor responses of patients to upcoming disease-modifying treatments are urgently needed. There are accumulating reports that soluble Ab oligomers, rather than amyloid fibrils, are the principal pathogenic species in AD. However, there is still no consensus on what species of Ab oligomers in the brains of AD patients is most toxic, and widely available assays to quantify such Ab oligomers are needed. Methods: We developed a novel enzyme-linked immunosorbent assay (ELISA) specific for high-molecular weight (HMW) Ab oligomers using the same amino-terminal Ab antibody for both antigen capture and detection (BAN50-BAN50 ELISA) and determined the levels of HMW Ab oligomers together with monomeric Ab species, Abx-40 (Ab40) and Abx-42 (Ab42) in the same samples of cerebrospinal fluid (CSF) from 18 patients with clinically diagnosed AD, 7 patients with mild cognitive impairment who later converted to AD (MCI-C) and 25 age-matched control subjects. Results: The size-exclusion chromatography (SEC) analysis of Ab oligomers made from synthetic Ab1-42 revealed that our ELISA specifically detected HMW Ab oligomers of 40-200 kDa without detection of monomers and low-molecular weight oligomers (dimers, trimers, tetramers and hexamers). Using this ELISA, we detected significantly higher (p < 0.0001) signals in CSFs from 25 patients with AD or mild cognitive impairment (MCI) compared with 25 age-matched controls. The area under the curve in the receiver operating characteristic analysis for the CSF HMW Ab oligomers was greater than that for the CSF Abx-42 in the discrimination between the AD/MCI and control groups. Furthermore, the CSF levels of HMW Ab oligomers showed a negative correlation with Mini-Mental State Examination scores in the AD/MCI group. Conclusions: We conclude that the CSF HMW Ab oligomers detected by our ELISA could be useful as a diagnostic marker for AD, and also as a potential surrogate marker for the disease severity. Our results support the idea that soluble HMW Ab oligomers play a critical role in the pathogenesis and progression of AD. P3-211
BUCCAL MICRONUCLEUS CYTOME BIOMARKERS MAY BE ASSOCIATED WITH ALZHEIMER’S DISEASE
Michael Fenech, Philip Thomas, CSIRO, Adelaide, Australia. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is a progressive degenerative disorder of the brain and is the commonest form of dementia. We tested the hypothesis that buccal mucosa in AD reflect aspects of reduced regenerative potential such