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Expression of five miRNA targets in hippocampus and cerebrospinal fluid in Alzheimer's disease
Poster Presentations: P2 optimal atlases as well as the refinement strategy significantly improved the overall quality of the segmentation. Table 1 Accuracy results
Dice (%) D (%)
P2-027
Multi-Atlas alone
Multi-Atlas after refinement
FreeSurfer cross-sectional
86.3 (3.3) 5.9 (3.8)
88.8 (1.9) 5.4 (4.1)
80.1 (2.8) 6.3 (5.1)
DEVELOPMENT OF A GOLD NANOPARTICLE ELISA TO DETECT LOW-ABUNDANT PROTEINS IN CEREBROSPINAL FLUID FOR DIAGNOSIS OF ALZHEIMER’S DISEASE
Mareike M€ uller, Dick Schijven, Kim Bruggink, Jan-Hendrik Venhuizen, H. Bea Kuiperij, Marcel M. Verbeek, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands. Background: Cerebrospinal fluid (CSF) analysis is currently becoming integrated into the diagnostic work-up of Alzheimer’s disease (AD). A combination of amyloid-b42, total and phosphorylated tau proteins can identify AD with a sensitivity and specificity above 90%. Nonetheless, their use is limited in differentiating between AD and other types of dementia, which leads to the requirement of new biomarkers with more discriminative capacity. Yet, many protein biomarkers are present at low concentrations in CSF. We hypothesize that the complex of amyloid-b with apolipoprotein E (ApoE) may serve as such low-abundant, specific biomarker for AD. We therefore aim to measure this protein complex in CSF by sandwich ELISA using gold nanoparticles as detection. Because these nanoparticles are able to bind large amounts of detection enzyme, the signal strongly increases and allows measurements of amyloid-b/ApoE complex at low concentrations. Methods: Magnetic particles, coated with an antibody against ApoE, capture the amyloid-b/ApoE complex. Gold nanoparticles are coated simultaneously with an antibody against amyloid-b, and a detection enzyme. After adding the gold nanoparticles to the magnetic-particle-antigen solution, the sandwich is formed and can be detected. The new sandwich ELISA set-up is compared to the conventional ELISA in terms of limit of detection, and amyloid-b/ApoE complex will be quantified in CSF samples. Results: Our current results demonstrate that antibodies can be coupled to both magnetic particles and gold nanoparticles. Moreover, enzymes can be successfully coupled to gold nanoparticles. Subsequently, both particles containing an antibody are also able to bind the antigen of interest, and can be implemented in a sandwich ELISA. Using gold nanoparticles, we can detect lower concentrations of the antigen than the conventional sandwich ELISA does. Conclusions: It is feasible to construct the different elements of the gold nanoparticle ELISA and to measure the antigen at low levels. Future studies will indicate whether the assay is able to measure amyloid-b/ApoE complex in CSF, and whether this complex can serve as a novel CSF biomarker for discrimination of AD and other dementias. P2-028
EXPRESSION OF FIVE MIRNA TARGETS IN HIPPOCAMPUS AND CEREBROSPINAL FLUID IN ALZHEIMER’S DISEASE
Mareike M€ uller, Giovanni Perrone, H. Bea Kuiperij, Marcel M. Verbeek, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands. Background: The small, only 19-22 nucleotides long miRNAs play a prominent role in regulating protein function in cells. More than 700 miRNAs have been identified in humans, and approximately 70% is expressed in the brain. Therefore, miRNAs have been suggested as indicators for Alzheimer’s disease (AD). Currently available cerebrospinal fluid (CSF) protein biomarkers (i.e. amyloid-b42, total and phosphorylated tau proteins) are able to diagnose AD with an accuracy of w80-90%. However, the differentiation between AD and other dementias using these protein markers, is more challenging. Here, we aim to identify miRNAs that are differentially expressed in AD patients
P273
and healthy controls as possible new CSF biomarkers. Methods: Four different targets were selected from literature: miR9, let7f, miR34a and miR146b3p. These miRNAs were quantified by RT-qPCR in hippocampus tissue of 10 AD patients and 10 healthy controls. As internal controls we used the snoRNA’s RNU44 and RNU6b that show a relatively constant and highly abundant expression in the brain and are similar in length to miRNAs. The targets were also quantified in CSF of 10 AD patients and 10 healthy controls, using RTqPCR with and without an additional preamplification step. Here, miR24 served as internal control, due to its abundancy in the brain and in CSF. Results: In hippocampus the four targets showed no significant differences in expression between the AD and control samples (P>0.1). Unexpectedly, RNU44 showed a tendency for lower expression in AD samples compared to control samples (P <0.1), and was therefore considered as possible target in the CSF analysis. In CSF, only miR34a could be detected in all samples. However, miR34a expression did not differ between AD and control samples. Conclusions: Expression of the selected targets was much more pronounced in the hippocampus than in CSF, but no significant differences between AD and controls were detected. The concentration of several miRNAs, with the exception of miR24 and miR34a, may be too low to be detected in CSF. Using this panel of miRNAs in CSF, no suitable biomarker for the discrimination between AD and controls was identified yet. P2-029
DECIPHERING THE CORTICAL THICKNESS SIGNATURE: BIOMARKER FOR ALZHEIMER’S DISEASE OR FOR MEMORY?
Irene Meier1, Stuart Grieve2, Mayuresh Korgaonkar2, Molly Zimmerman3, Adam Brickman1, 1Columbia University, New York, New York, United States; 2University of Sydney Medical School, Sydney, Australia; 3Albert Einstein College of Medicine, Bronx, New York, United States. Background: Recent work from Dickerson and colleagues suggests that analysis of the cortical thickness in key brain regions can be used to identify individuals at greatest risk for development of Alzheimer’s disease (AD). It is unclear, however, whether this “signature” reflects early pathological changes due to AD or whether it is a reflection of memory functioning, which, in turn is highly predictive of future development of AD. Here, we examined the relationship between the AD signature MRI biomarker and memory functioning in a group of neurologically healthy young (ostensibly years before any pathological changes due to AD) and older adults. Methods: High resolution structural MRI and comprehensive computer-based neuropsychological evaluations were conducted in 110 adults (age range 21-78, mean ¼ 46) from the Brain Resource International Database, accessed via the independent BRAINnet Foundation (www.BRAINnet.net). The groups were divided into younger adult (n ¼ 64, age 21-50) and older adult (n ¼ 46, age 50-78) groups. Cortical thickness was derived with FreeSurfer. We computed the average cortical thickness in eight regions that comprise the AD-signature (medial temporal lobe, temporal pole, inferior temporal, supramarginal gyrus, superior parietal, precuneus, middle frontal, superior frontal), weighted by the size of each region. Controlling for education and total cranial volume, we examined the relationship of AD-signature cortical thickness with performance on a memory test and a simple test of psychomotor speed (as control) with separate multiple regression analyses for each age group. Results: Mean AD-signature cortical thickness was positively associated with performance on a delayed free recall declarative list learning task in younger (Standardized beta ¼ 0.320, P ¼ 0.013) and in older (Standardized beta ¼ 0.525, P ¼ 0.001). Mean AD-signature cortical thickness was not associated with psychomotor speed (P>0.05) in either group. Conclusions: The results suggest that the cortical thickness signature is a specific marker for memory functioning across the adult lifespan, rather than a marker for AD pathology per se. Future work should determine whether neuropsychological testing has better diagnostic and prognostic utility than this MRI-derived measure. P2-030
INCREASED INTRATHECAL SYNTHESIS OF ANTIBODIES AGAINST TAU PROTEIN AND HEAVY NEUROFILAMENT IN ALZHEIMER’S DISEASE
Ales Bartos1, Lenka Fialova2, Jana Svarcova2, Daniela Ripova1, 1Prague Psychiatric Center, Prague, Czech Republic; 2Charles University in
Dice (%) D (%)
P2-027
Multi-Atlas alone
Multi-Atlas after refinement
FreeSurfer cross-sectional
86.3 (3.3) 5.9 (3.8)
88.8 (1.9) 5.4 (4.1)
80.1 (2.8) 6.3 (5.1)
DEVELOPMENT OF A GOLD NANOPARTICLE ELISA TO DETECT LOW-ABUNDANT PROTEINS IN CEREBROSPINAL FLUID FOR DIAGNOSIS OF ALZHEIMER’S DISEASE
Mareike M€ uller, Dick Schijven, Kim Bruggink, Jan-Hendrik Venhuizen, H. Bea Kuiperij, Marcel M. Verbeek, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands. Background: Cerebrospinal fluid (CSF) analysis is currently becoming integrated into the diagnostic work-up of Alzheimer’s disease (AD). A combination of amyloid-b42, total and phosphorylated tau proteins can identify AD with a sensitivity and specificity above 90%. Nonetheless, their use is limited in differentiating between AD and other types of dementia, which leads to the requirement of new biomarkers with more discriminative capacity. Yet, many protein biomarkers are present at low concentrations in CSF. We hypothesize that the complex of amyloid-b with apolipoprotein E (ApoE) may serve as such low-abundant, specific biomarker for AD. We therefore aim to measure this protein complex in CSF by sandwich ELISA using gold nanoparticles as detection. Because these nanoparticles are able to bind large amounts of detection enzyme, the signal strongly increases and allows measurements of amyloid-b/ApoE complex at low concentrations. Methods: Magnetic particles, coated with an antibody against ApoE, capture the amyloid-b/ApoE complex. Gold nanoparticles are coated simultaneously with an antibody against amyloid-b, and a detection enzyme. After adding the gold nanoparticles to the magnetic-particle-antigen solution, the sandwich is formed and can be detected. The new sandwich ELISA set-up is compared to the conventional ELISA in terms of limit of detection, and amyloid-b/ApoE complex will be quantified in CSF samples. Results: Our current results demonstrate that antibodies can be coupled to both magnetic particles and gold nanoparticles. Moreover, enzymes can be successfully coupled to gold nanoparticles. Subsequently, both particles containing an antibody are also able to bind the antigen of interest, and can be implemented in a sandwich ELISA. Using gold nanoparticles, we can detect lower concentrations of the antigen than the conventional sandwich ELISA does. Conclusions: It is feasible to construct the different elements of the gold nanoparticle ELISA and to measure the antigen at low levels. Future studies will indicate whether the assay is able to measure amyloid-b/ApoE complex in CSF, and whether this complex can serve as a novel CSF biomarker for discrimination of AD and other dementias. P2-028
EXPRESSION OF FIVE MIRNA TARGETS IN HIPPOCAMPUS AND CEREBROSPINAL FLUID IN ALZHEIMER’S DISEASE
Mareike M€ uller, Giovanni Perrone, H. Bea Kuiperij, Marcel M. Verbeek, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands. Background: The small, only 19-22 nucleotides long miRNAs play a prominent role in regulating protein function in cells. More than 700 miRNAs have been identified in humans, and approximately 70% is expressed in the brain. Therefore, miRNAs have been suggested as indicators for Alzheimer’s disease (AD). Currently available cerebrospinal fluid (CSF) protein biomarkers (i.e. amyloid-b42, total and phosphorylated tau proteins) are able to diagnose AD with an accuracy of w80-90%. However, the differentiation between AD and other dementias using these protein markers, is more challenging. Here, we aim to identify miRNAs that are differentially expressed in AD patients
P273
and healthy controls as possible new CSF biomarkers. Methods: Four different targets were selected from literature: miR9, let7f, miR34a and miR146b3p. These miRNAs were quantified by RT-qPCR in hippocampus tissue of 10 AD patients and 10 healthy controls. As internal controls we used the snoRNA’s RNU44 and RNU6b that show a relatively constant and highly abundant expression in the brain and are similar in length to miRNAs. The targets were also quantified in CSF of 10 AD patients and 10 healthy controls, using RTqPCR with and without an additional preamplification step. Here, miR24 served as internal control, due to its abundancy in the brain and in CSF. Results: In hippocampus the four targets showed no significant differences in expression between the AD and control samples (P>0.1). Unexpectedly, RNU44 showed a tendency for lower expression in AD samples compared to control samples (P <0.1), and was therefore considered as possible target in the CSF analysis. In CSF, only miR34a could be detected in all samples. However, miR34a expression did not differ between AD and control samples. Conclusions: Expression of the selected targets was much more pronounced in the hippocampus than in CSF, but no significant differences between AD and controls were detected. The concentration of several miRNAs, with the exception of miR24 and miR34a, may be too low to be detected in CSF. Using this panel of miRNAs in CSF, no suitable biomarker for the discrimination between AD and controls was identified yet. P2-029
DECIPHERING THE CORTICAL THICKNESS SIGNATURE: BIOMARKER FOR ALZHEIMER’S DISEASE OR FOR MEMORY?
Irene Meier1, Stuart Grieve2, Mayuresh Korgaonkar2, Molly Zimmerman3, Adam Brickman1, 1Columbia University, New York, New York, United States; 2University of Sydney Medical School, Sydney, Australia; 3Albert Einstein College of Medicine, Bronx, New York, United States. Background: Recent work from Dickerson and colleagues suggests that analysis of the cortical thickness in key brain regions can be used to identify individuals at greatest risk for development of Alzheimer’s disease (AD). It is unclear, however, whether this “signature” reflects early pathological changes due to AD or whether it is a reflection of memory functioning, which, in turn is highly predictive of future development of AD. Here, we examined the relationship between the AD signature MRI biomarker and memory functioning in a group of neurologically healthy young (ostensibly years before any pathological changes due to AD) and older adults. Methods: High resolution structural MRI and comprehensive computer-based neuropsychological evaluations were conducted in 110 adults (age range 21-78, mean ¼ 46) from the Brain Resource International Database, accessed via the independent BRAINnet Foundation (www.BRAINnet.net). The groups were divided into younger adult (n ¼ 64, age 21-50) and older adult (n ¼ 46, age 50-78) groups. Cortical thickness was derived with FreeSurfer. We computed the average cortical thickness in eight regions that comprise the AD-signature (medial temporal lobe, temporal pole, inferior temporal, supramarginal gyrus, superior parietal, precuneus, middle frontal, superior frontal), weighted by the size of each region. Controlling for education and total cranial volume, we examined the relationship of AD-signature cortical thickness with performance on a memory test and a simple test of psychomotor speed (as control) with separate multiple regression analyses for each age group. Results: Mean AD-signature cortical thickness was positively associated with performance on a delayed free recall declarative list learning task in younger (Standardized beta ¼ 0.320, P ¼ 0.013) and in older (Standardized beta ¼ 0.525, P ¼ 0.001). Mean AD-signature cortical thickness was not associated with psychomotor speed (P>0.05) in either group. Conclusions: The results suggest that the cortical thickness signature is a specific marker for memory functioning across the adult lifespan, rather than a marker for AD pathology per se. Future work should determine whether neuropsychological testing has better diagnostic and prognostic utility than this MRI-derived measure. P2-030
INCREASED INTRATHECAL SYNTHESIS OF ANTIBODIES AGAINST TAU PROTEIN AND HEAVY NEUROFILAMENT IN ALZHEIMER’S DISEASE
Ales Bartos1, Lenka Fialova2, Jana Svarcova2, Daniela Ripova1, 1Prague Psychiatric Center, Prague, Czech Republic; 2Charles University in