DIFFUSION KURTOSIS IMAGING: A BIOMARKER FOR EARLY DIAGNOSIS OF ALZHEIMER'S DISEASE?

Oral Sessions: O2-03: Neuroimaging: Imaging in Mild Cognitive Impairment and Subjective Memory Complaint

Fig. 1)+2) Box plots, showing no significant difference between SMC and MCI group in mean FA and mean MD (mean +/- stand. error). 3) The FA map of one SMC person with overlaid mean FA skeleton (blue) and its mask with a threshold of 0.3 (green). 4) The correlation of mean FA value with one PA measurement at baseline Table comparison of different diffusion parameters in the SMC and MCI group

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non-linear transformations. Cortical thickness was measured with CIVET and BEaST pipelines using T1 weighted data. [18F]FDG voxel-based group comparisons between accumulators and non-accumulators were calculated with PET-SUVR resampled and blurred with a Gaussian filter. Vertex-based group comparisons were calculated using RMINC. Accumulators and nonaccumulators were determined by taking the [18F]Florbetapir SUVr ratio of baseline and follow-up. Results: Non-accumulators showed [18F]FDG declines in EMCI, LMCI, and AD, but not controls. Left hippocampi [18F]FDG reduction were observed in EMCI (t¼-3.2, p¼0.0026) and LMCI (t¼-3.3, p¼0.0092). Right hippocampi [18F]FDG reductions were observed in EMCI (t¼-3.1, p¼0.0034), LMCI (t¼-3.1, p¼0.0062), and AD (t¼-3.3, p¼0.0109). Left dorso-lateral prefrontal cortex (DLPFC) [18F]FDG reductions were observed in EMCI (t ¼-3.5,p<0.001), LMCI (t¼-3.3, p¼0.0092), and AD (t¼-4.6, p<0.008). Right DLPFC [18F]FDG reductions were observed in EMCI (t¼-3.1, p¼0.0034), LMCI (t ¼-3.1, p¼0.0092), and AD (t¼-3.5, p¼0.008). Left posterior cingulate cortex (PCC) [18F]FDG reductions were observed in EMCI (t¼-3.5, p¼0.001) and LMCI (t¼-3.5, p¼0.0067). Right PCC [18F]FDG reductions were observed in EMCI (t¼ -3.3, p¼0.0019), LMCI (t ¼-3.3, p¼0.009) and AD (t¼3.3, p¼0.009) (Figure 1). Cortical thickness declines were only seen in non-accumulators in the LMCI and AD groups. Conclusions: Our results support the concept that declines in brain metabolism and cortical thickness follow the plateau stage of amyloidosis. While metabolism declines predominate in limbic and heteromodal cortices, cortical thickness declines were present diffusely. It seems that brain metabolism and structure are stable in amyloid accumulators.

Group Mean (RSE %)1 Parameter

SMC

MCI

Sig.2

FA MD AD RD

.5054 (0.89) .000777 (0.64) .001250 (0.40) .000540 (1.11)

.5014 (0.88) .000781 (0.89) .001253 (0.56) .000545 (1.28)

.52 .66 .70 .66

1 2

Relative standard error ([SE/M]*100) Independent samples t-test

O2-03-05

HYPOMETABOLISM AND CORTICAL ATROPHY IN [18F]FLORBETAPIR ACCUMULATORS AND NON-ACCUMULATORS

Sara Mohades1, Sulantha Sanjeewa Mathotaarachchi2, Maxime Parent3, Monica Shin3, Seqian Wang4, Andrea Lessa Benedet4, Antoine Leuzy3, Thomas Beaudry4, Eduardo Rigon Zimmer5, Laksanun Cheewakriengkrai6, Daliah Farajat5, Vladmir Fonov4, Simon Eskildsen7, Serge Gauthier8, Pedro Rosa-Neto9, 1McGill Center for Studies in Aging, Montreal, Quebec, Canada; 2McGill University, Montreal, Quebec, Canada; 3McGill Centre for Studies in Aging, Montreal, Quebec, Canada; 4McGill University, Montreal, Quebec, Canada; 5McGill University, Montreal, Quebec, Canada; 6McGill University, Montreal, Quebec, Canada; 7Aarhus University, Aarhus, Denmark; 8McGill Center for Studies in Aging, Montreal, Quebec, Canada; 9MCSA, Montreal, Quebec, Canada. Contact e-mail: [email protected] Background: It has been proposed that amyloidosis starts at the asymptomatic phase of Alzheimer’s Disease (AD) and is characterized by an initial fast accumulation phase, subsequently reaching a plateau. Hypometabolism and cortical atrophy follow the initial amyloid accumulation phase. Few studies have explored the concept of amyloid "accumulators" and "non-accumulators" with [11C]PIB, particularly in the context of cognitive decline. Here, we compare neurodegeneration in [18F]florbetapir accumulators and non accumulators based on a 24 month assessment. Methods: We analyzed a subsample of 206 participants (60 CN, 79.9 6 6.1 yo; 108 EMCI, 71.8 67.4 yo;19 LMCI, 73.9 611.6 yo; 19 AD, 77.3 6 9.8 yo) at baseline and 24 month follow-up from the ADNI GO and ADNI 2 cohort. PET standard uptake ratios (SUVR) were calculated using median counts of cerebellar GM and pons for [18F]florbetapir and [18F]FDG scans, respectively. PET images were registered to the MNI space using the previously defined

Figure 1. Sagittal (right hemisphere) and coronal sections showing D% [18F]FDG t- stats [Accumulators < Non-accumulators]. O2-03-06

DIFFUSION KURTOSIS IMAGING: A BIOMARKER FOR EARLY DIAGNOSIS OF ALZHEIMER’S DISEASE?

Hanne Struyfs1, Wim Van Hecke2, Sylvie Slaets1, Stefan Van der Mussele3, Maya De Belder4, Laura Wuyts5, Benjamin Peters5, Frank De Belder6, Paul Parizel5, Sebastiaan Engelborghs1, 1University of Antwerp, Antwerp, Belgium; 2IcoMetrix, Leuven, Belgium; 3University of Antwerp, Antwerp (Wilrijk), Belgium; 4University of Ghent, Gent, Belgium; 5Antwerp University Hospital & University of Antwerp, Edegem, Belgium; 6Antwerp University Hospital, Edegem, Belgium. Contact e-mail: [email protected] Background: In recent studies it has been observed that structural and functional disruptions in the relationship between anatomically distinct brain regions occur in patients with dementia, supporting the notion of a disconnection syndrome. Structural and functional brain alterations are hypothesized to reflect, at least partially, the progressive impairment of fiber tract connectivity and integrity. Diffusion kurtosis imaging (DKI) studies structural brain connectivity changes as well as white matter integrity and might serve as a potential biomarker of Alzheimer’s disease (AD). Indeed, DKI involves acquisition of diffusion tensor imaging (DTI) across several b values, while DTI acquires diffusion data at a single b value. In preclinical and clinical studies, modeling diffusions

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Oral Sessions: O2-04: Molecular and Cell Biology: APP, Abeta

with DKI can provide a more sensitive measure of diffusion behavior and can be used to interrogate gray matter as well as white matter tissue in the brain. Methods: This prospective study included patients with probable AD (n¼19) and mild cognitive impairment (MCI) (n¼18) and healthy controls (n¼14). MCI and probable AD were diagnosed according to Petersen and NINCDS-ADRDA criteria. Controls had no cognitive decline, and no central nervous system pathology.The imaging protocol included structural imaging and DKI. DKI datasets were transformed to a population-specific atlas space. Fractional anisotropy (FA), mean diffusivity (MD) and mean kurtosis (MK) were then compared across the groups. Results: Differences in diffusion and kurtosis values between controls and MCI and AD patients were shown. The main differences were found between the AD and control group. The results suggest that the MD and MK are more sensitive parameters compared to FA to detect differences between both groups.Furthermore, the mean kurtosis was found to be the most sensitive parameter to discriminate control subjects from MCI patients, while the MD was the most sensitive parameter to detect significant changes between MCI and AD subjects. Changes were mainly found in the inferior longitudinal fasciculus, splenium of the corpus callosum and posterior cingulate. Conclusions: Decreased kurtosis values in the inferior longitudinal fasciculus, splenium of the corpus callosum and posterior cingulate could serve as a biomarker for early AD diagnosis. MONDAY, JULY 14, 2014 ORAL SESSIONS O2-04 MOLECULAR AND CELL BIOLOGY: APP, ABETA O2-04-01

INTRACELLULAR ANTIBODIES FOR FUNCTIONAL INTERFERENCE WITH SUBCELLULAR AB OLIGOMERS

Giovanni Meli1, Nina Krako2, Annalisa Manca3, Agnese Lecci3, Maria Chiara Magnifico4, Raffaella Scardigli5, Paolo Sarti4, Antonino Cattaneo2, 1European Brain Research Institute, Rome, Italy; 2Scuola Normale Superiore, Pisa, Italy; 3EBRI, Rome, Italy; 4University of Rome, Rome, Italy; 5EBRI and CNR, Rome, Italy. Contact e-mail: [email protected] Background: Amyloidß oligomers (AßOs) are considered crucial players in the early pathogenesis of Alzheimer’s Disease (AD) but their intracellular formation and actions are still poorly understood. The use of intracellular antibodies (intrabodies) allows selectively interfering in living cells with posttranslationally modified, or processed, proteins, such as the Amyloid Precursor Protein (APP) and its products Aß/AßOs, in a way that cannot be performed with the RNAi-based methods. Here, conformation-sensitive anti-AßOs antibody fragments (Meli et al., J Mol Biol 2009) are exploited as intrabodies. Methods: We expressed recombinant anti-AßOs intrabodies targeted to distinct subcellular compartments of different types of cultured cells. The functional effects of intrabody expressed in familial AD (fAD) CHO cell models (Meli et al., Alz&Dementia 2011) were investigated in terms of mitochondrial physiology and intracellular signalling pathways. Furthermore we targeted intrabodies in primary cells derived different from the AD mouse model Tg2576: mouse embryonic fibroblasts (MEF); mouse adult fibroblasts (MAF); neuronal stem cells (NSC) from embrionic spinal cord or adult brain subventricular zone (SVZ), mantained in vitro as neurosphere cultures. Results: Recently we demonstrated some AD-related mitochondrial dysfunctions and bioenergetic deficit in CHO cell models of Aß oligomerization (Krako et al., J Alz Disease 2013). Here, we demostrate that the anti-AßOs intrabodies targeted to the Endoplasmic Reticulum and to early secretory compartments, through their modulatory effects on the levels and assembly of AßOs, trigger a strong rescue of mitochondrial dysfunctions and bioenergetic deficits in fAD CHO cell models. In these cells, we also demonstrated that the AßOs targeted to the secretory pathway, mitochondria and to an ER-associated degradation pathway, differentially modulate the biochemical patterns of intracellular and extracellular Aß/AßOs. Finally, we are investigating the actions of anti-AßOs intrabodies in MAF, MEF and NSC. Conclusions: Different pools of subcellular AßOs can be selectively targeted by intrabodies. The anti-AßOs intrabodies are unique tools to study the intracellular actions of AßOs; in this way we established an AD-relevant functional link ER-mitochondria by targeting AßOs in the ER. In conclusion, sub-

cellular pools of AßOs are relevant targets for new therapeutics and anti-AßOs intrabodies can be exploited as new diagnostics and therapeutics. O2-04-02

INCREASED AB OLIGOMER BINDING TO CNS SYNAPSES IN MICE WITH PERIPHERAL INSULIN RESISTANCE AND REDUCED CIRCULATING ADIPONECTIN

Giulio Taglialatela, Wenru Zhang, Demidmaa Tuvdendorj, Batbayar Tumurbaatar, Nicola I. Abate, University of Texas Medical Branch, Galveston, Texas, United States. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) and type 2 diabetes mellitus (T2DM) are increasingly common in the general population, an epidemiological observation linking these two chronic diseases to the world-wide epidemic of obesity. Insulin resistance, the main feature of T2DM, is also often described in AD patients, thus suggesting that the metabolic determinants of T2DM constitute a risk factor for AD development. However, the exact mechanisms linking the pathogenesis of peripheral insulin resistance to the CNS dysfunction described in AD, a critical knowledge for the development of new, effective therapies for AD, are largely unknown. Methods: To address this knowledge gap, in this studies we have used a transgenic mouse model with adipose tissue dysfunction (defective adipocyte maturation) which we shown to recapitulate peripheral insulin resistance to glucose disposal and lipid abnormalities in humans. This model (At ENPP1 -Tg) involves adipose tissue-specific over-expression of ecto-nucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1), a protein known to be a negative regulator of insulin receptor activation and found overexpressed in humans with metabolic syndrome, coupled to reduced adiposederived adiponectin and increased susceptibility to high fat diet-driven systemic insulin resistance. Results: We found that brain synaptosomes isolated from the At ENPP1 -Tg mice show altered lipid composition, reduced insulin signaling activation, along with altered NMDAR levels and CREB phosphorylation. Most notably, we found that amyloid beta (Ab) oligomers promptly bind to brain slices from the At ENPP1 -Tg mice as compared to wild-type mice. We further found that A b binding to synapses may be reduced by adiponectin, an adipose tissue-derived hormone that is reduced in At ENPP1 -Tg mice. Conclusions: Given that binding of A b oligomers to synapses is a major neurodysfunctional event leading to onset and progression of cognitive decline in AD, our results suggest a new concept where increased synaptic vulnerability to A b oligomers and consequent increased risk of AD may be driven by adipose tissue dysfunction and associated reduction of adiponectin production which ultimately underscores metabolic syndrome and systemic insulin resistance. This new knowledge provides a molecular mechanism for increased risk of Alzheimer’s disease in people with metabolic syndrome and T2DM and lays the foundation for the development of future effective therapeutic approaches.Supported by: NIH/ NIA 1R01AG042890 to GT. O2-04-03

MEMORY DEFICITS OF 5XFAD MICE IN THE OLFACTORY H-MAZE TEST CORRELATE WITH PLAQUES DEVELOPMENT AND ARE PREVENTED BY 5-HT4R AGONIST TREATMENTS

Patrizia Giannoni1, Kevin Baranger2, Sarah Girot2, Stephane Girard2, Florence Gaven3, Marlyse Jacquet2, Martine Migliorati2, Santiago Rivera4, Sylvie Claeysen1, Franc¸ois Roman2, 1CNRS, UMR-5203, Institut de Genomique Fonctionnelle, Montpellier, France; 2Aix-Marseille Univ, Marseille, France; 3CNRS, UMR-5203, Institut de Genomique Fonctionnelle, Montpellier, France; 4UMR 6184 CNRS-Universite de la Mediterranee, Marseille, France. Contact e-mail: [email protected] Background: The frontal cortex is one of the areas early involved in Alzheimer’s disease alterations. 5xFAD mice show memory deficits already at 4 months of age in the olfactory H maze, a behavioural test specifically developed to assess frontal functions in mouse models. We have previously demonstrated that chronic 5-HT 4 R agonist treatments of 5xFAD mice with RS 67333 slow down plaques formation and prevent memory deficits in the novel object recognition test. In the present study, we evaluated the impact of chronic 5-HT 4 R activation on amyloid load in the frontal cortex and on mouse performances in the olfactory H-maze. Methods: Two groups of 5xFAD mice and wild type (WT) littermates were treated with RS 67333