Poster Presentations P4 P481

microglial cells, as well as the signal transduction pathways responsible for

such phenotypical changes.

P4-168 ANTEMORTEM IL-6 LEVELS ASSOCIATED WITH

Vascular

Score

N

0 8

1 8

2 6

VASCULAR PATHOLOGY BUT NOT ALZHEIMER

PATHOLOGY IN CASES FROM THE EINSTEIN

AGING STUDY

Carol A. Derby1, Richard B. Lipton1, Amy Sanders1, Dennis Dickson2,1Albert Einstein College of Medicine, Bronx, NY, USA; 2Mayo Clinic,

Jacksonville, FL, USA. Contact e-mail: cderby@aecom.yu.edu

Background: Inflammation has been implicated in the pathogenesis of de-

mentia, and proinflammatory cytokines have been associated with cogni-

tive decline in some studies. Chronic inflammation might exacerbate

neurodegenerative Alzheimer’s Disease (AD) pathology, or may lead to

vascular pathology via atherogenic mechanisms. Few studies have exam-

ined the correlation of antemortem systemic markers of inflammation

with neuropathologic findings. Overexpression of the cytokine interleukin

6 (IL-6) has been reported in brains of AD patients, and elevated circulat-

ing IL-6 levels have been correlated with cognitive decline. Methods: We

analyzed the relation of antemortem levels of circulating IL-6 to vascular

and AD pathology in a series of 22 autopsy cases from the Einstein Aging

Study (EAS). All subjects were part of the EAS longitudinal cohort, and

were followed annually to death. At enrollment, subjects were age > 70

years, and non-demented. IL-6 values were log transformed for analyses.

Pathological diagnosis of AD was based on NIA-Regan criteria. A patho-

logical diagnosis of vascular dementia was determined using NACC

methods. Vascular lesions were quantified using a 3 point scale (0,1,2).

Braak staging was applied to quantify neurofibrillary tangles. Results:

The series included the following neuropathological diagnoses: 4 AD, 6

normal, 4 VaD, 2 Lewy-body disease, 6 other. Mean time from blood as-

say to death was 4.5 years, and the mean age of subjects at death was 83

years. IL-6 level was correlated with vascular lesion score (r¼0.56,

p¼0.0006), but not with Braak neurofibrillary tangle stage (r¼-0.29,

p¼0.20). Mean IL-6 values were highest in the VaD group and were

similar in those with neuropathological diagnosis of AD or normal. In

ANOVA models adjusted for age and time from blood draw to death,

mean log IL-6 increased with increasing vascular lesion score (p¼0.001)

and after additional adjustment for Braak neurofibrillary tangle stage the

trend remained significant (p¼0.05). Conclusions: IL-6 is associated

with vascular brain pathology independent of the extent of AD pathology.

The interrelationship of vascular and AD pathologies is complex, and

further work is needed regarding the role of inflammatory markers in the

progression of these pathologies.

Mean (SE) log IL6, adjusted

for age, time from blood

draw to death

Mean (SE) log IL6,

adjusted for age, time

from blood draw to death,

and Braak stage

0.36 (0.09) 0.35 (0.12)

0.31 (0.09) 0.51 (0.14)

0.86 (0.11) 0.84 (0.14)

P4-169 b-AMYLOID NEUROTOXICITY IN ORGANOTYPIC

HIPPOCAMPAL SLICE CULTURE IS ATTENUATED

BY MELATONIN: INVOLVEMENT OF GSK-3b, TAU

AND NEUROINFLAMMATION

Christianne Salbego1, Juliana B. Hoppe1, Rudimar L. Frozza1,

Ana Paula Horn1, Ricardo A. Comiran1, Andressa Bernardi1,

Maria Martha Campos2, Ana Maria O. Battastini1, 1Universidade Federal doRio Grande do Sul, Porto Alegre, Brazil; 2Pontificia Universidade Catolica

do Rio Grande do Sul, Porto Alegre, Brazil. Contact e-mail: salbego@terra.

com.br

Background: According to the amyloid cascade hypothesis, neurodegener-

ation in Alzheimer disease begins with the abnormal processing of the am-

yloid precursor protein (APP) and results in the production, aggregation and

deposition of the Ab peptide. The buildup of Ab aggregates in the Alz-

heimer’s disease is followed by the formation of intracellular neurofibrillary

tangles, induced by the hyperphosphorylation of tau protein, and activation

of neuroinflammatory reactions. Current therapies for Alzheimer disease

provide effective symptomatic relief, particularly in early stages of the dis-

ease. Substantial evidence indicates that melatonin has neuroprotective

properties in AD. However, the cellular and molecular mechanisms remain

far from established. The aim of this study was investigate whether melato-

nin possesses a neuroprotective effect against Ab25-35-induced toxicity.

Methods: Organotypic hippocampal slice cultures were exposed to

25mM of Ab25-35 for 6h, 12h, 24h and 48h with or without a chronic

pre-treatment with 25mM, 50mM or 100mM of melatonin. Cell death was

measured by propidium iodide (PI) uptake. We investigated the involve-

ment of GSK-3b, tau protein and the astrogilal and microglial activation

by performing Western blot assay with specifics antibodies. Also, we mea-

sured some cytokines levels by ELISA assay. Results: Our results show

that Ab25-35 peptide caused around 30% of cell damage in hippocampus,

a significant increase when compared to controls cultures (about 4% of cel-

lular damage). The chronic pre-treatment with 50mM and 100mM of mela-

tonin decreased the cell death to around 10% and 5%, respectively. In

addition, melatonin significantly prevented the activation of GSK-3b at

12h after Ab exposure, and the hyperphosphorylation of tau protein and

the glial and microglial activation after 48h of Ab exposure. Likewise, mel-

atonin prevented the Ab-induced increase in TNF-a and IL-6 levels. Con-

clusions: The overall results of our work suggest that melatonin may

provide an effective neuroprotection against Ab-induced neurotoxicity by

reducing the hyperphosphorylation of tau protein, possibly by preventing

GSK-3b activation, and by preventing glial activation, reducing TNF-

a and IL-6 levels and consequently neuroinflammation.

P4-170 THE ROLE OF S100A9 IN THE

NEUROINFLAMMATION OF ALZHEIMER’S

DISEASE TRANSGENIC MOUSE MODEL, TG2576

Keun-A Chang, Tae-Young Ha, Jeonga Kim, Yoo-Hun Suh, Seoul NationalUniversity, Seoul, Republic of Korea. Contact e-mail: kachang74@gmail.

com

Background: Neuroinflammation, insoluble protein deposition and neuro-

degeneration are important features of Alzheimer’s disease (AD) in the

brain. Recent studies have shown that the intracytoplasmic C-terminal frag-

ments of amyloid precursor protein (APP-CTFs including AICD) as well as

amyloid b (Ab) may be involved in the pathogenesis of AD. CTFs have

been reported to play a role as a transcription factor, but candidate down-

stream genes need to be identified. Methods: To find the regulatory genes

causing neuroinflammation in the pathology of AD, we performed microar-

ray gene analysis in 11-month-old APPV717I-CT100 transgenic mice

(CT-Tg) and isolated the S100a9 gene induced in the brains of CT-Tg

mice. Results: We found that S100a9 gene expression was highly localized

mainly in microglia cells in the brains of Tg2576 mice, patients with AD,

and CT-Tg mice. We observed that the mRNA and protein levels of

S100a9 were remarkably increased by CTF or Ab in BV2 cells, a murine

microglial cell line. In addition, a luciferase assay indicated that CTF was

associated with the promoter region of the S100a9 gene. Silencing of

S100a9 expression decreased inflammatory cytokines induced by Ab or

CTF. Using a technique called short hairpin RNA (shRNA)-mediated

knockdown, S100a9 gene expression in the brains of 15 month-old-

Tg2576 mice was silenced and the pathology of AD was significantly re-

duced in the brain in Tg2576 mice. Also, the learning ability of Tg2576

mice improved. Conclusions: Taken together, results of this study strongly

suggest that S100a9 plays a role in the neuropathology of AD and the in-

hibition of S100a9 has potential utility in ameliorating neurologic damage

of the AD Tg mouse model, Tg2576 and may represent a novel approach in

the treatment of AD.