Developing Topics e67
Background: The major neuropathological hallmarks in the brains of
AD patients are senile plaques formed by beta amyloid (Aß) aggregates
and neurofibrillary tangles, containing hyperphosphorylated tau, both
causing progressive neuronal dysfunction. These pathological alterations
are likely causally involved in eventual neuronal death, particularly in
brain regions related to memory and cognition. The first attempt to de-
velop an active vaccine to Aß, AN1793, failed in clinical trials due to
a Th1 type T cell immune response, attributed to the adjuvant used,
QS21 and polysorbate 80, provoking a meningoencephalitis-like effect
and death in 6% of the patients. To overcome this failure, we designed
a novel Aß1-42 active vaccine incorporated and delivered in a liposomal
adjuvant that evoked aTh2 T cell reaction. Methods: Aß was
incorporated and delivered in a liposomal matrix composed of phospha-
tidylcholine: phosphatidylglycerol: cholesterol:sphingosine-1-phosphate
(EB101) and administered intraperitoneally for seven months to double
transgenic mice (B6C3-Tg (APPswe,PSEN1dE9)), before or after the
AD pathology was developed (In 7-week and 37-week old mice respec-
tively). Aß plaques and neurofibrillary tangles were quantified by ELI-
SAs and brain histology using specific antibodies. Basal
immunological interaction between the T-cells in the affected hippocam-
palarea and other immune activation markers, including glial fibrillary
acidicprotein (GFAP) (astroglia) and CD-45 (B-cells) were also studied
using immunoreactive-specific staining. T-cell reaction type was as-
sessed by cytokine type production. Results: Both preventive and thera-
peutic vaccination with EB101 resulted in a marked inhibition of Aß
deposits (60 to 80%), a reduction of neurofibrillary tangles (70 to
90%) and almost completely suppression of reactive gliosis as measured
by GFAP immunoreactivity and cytokine profile, consistent with
a marked decrease in amyloidosis-induced inflammation. No external
neurological deficits were observed as a result of EB101 immunization
(limb paralysis or brain atrophy). Psychomotor and cognitive tests per-
formed in a rota-rod in these animals also showed a dramatic improve-
ment in learning and psychomotor activity in the EB101-treated group.
Conclusions: The present findings unequivocally indicate that immuniza-
tion with EB101 not only prevents and reverses AD neuropathology and
underlined inflammation, but also improves cognitive symptoms, thus
warranting further studies.
P4-445 EARLYAND CHRONIC TREATMENT WITH
DANTROLENEBLOCKEDLATER LEARNINGAND
MEMORY DEFICITS IN OLDER ALZHEIMER’S
TRIPLE TRANSGENIC MICE
Jun Peng, Ge Liang, Saadet Inan, Zhen Wu, Donald Joseph,
Qingcheng Meng, Yi Peng, Maryellen Eckenhoff, Huafeng Wei, University
of Pennsylvania, Philadelphia, Pennsylvania, United States.
Background: Disruption of intracellular calcium homeostasis via abnor-
mal and excessive activation of ryanodine receptors plays an important
role in the neuropathology of Alzheimer’s disease (AD). We investigated
the effects of dantrolene, a ryanodine receptor antagonist and a clinically
available drug to treat malignant hyperthermia in anesthesia practice, on
the cognitive function and pathology in a triple transgenic mouse model
(3xTgAD) of AD. Methods: 3xTgAD mice were treated with continuous
intracerebraventricular (ICV) injection of dantrolene (100 mM, 2-4 ml
per day) or vehicle control (DMSO, 2-4 ml per day) starting at 2 months
of age using implanted Alzet pumps. The drug or vehicle supplies in the
pumps were changed once a month for 3 months. Thereafter, the mice
were continuously treated with subcutaneous injections of dantrolene
(5 mg/kg) or vehicle control (DMSO) 3 times a week until 13 months
of age. Additional control groups consisted of wild type and 3xTgAD
mice which received no treatment. Learning and memory were tested
in all animals at 2, 6, 10 and 13 months of age using the Morris Water
Maze. All mice were then euthanized and the brains analyzed for amy-
loid plaques, cytosolic cytochrome C, phosphorylated tau and synaptic
proteins (PSD 95) using quantitative immunohistochemistry and western
blot assays. Results: 3xTgAD control mice first displayed learning and
memory impairments at 10 months, which were more pronounced at 13
months of age. Long-term dantrolene treatment nearly abolished these
learning and memory deficits in 3xTgAD mice compared to vehicle and
wild type controls. Dantrolene treatment also significantly decreased the
number of amyloid plaques in the hippocampus and the amount of cyto-
chrome C in the cytosolic space, but had no effect on phosphorylated
tau or synaptic marker levels in AD brains. Finally, neither dantrolene
nor vehicle treatment significantly affected motor function. Conclusions:
Our results suggest that dantrolene, a currently available ryanodine recep-
tor calcium channel antagonist, significantly improves cognition in a mu-
rine model of Alzheimer’s disease and is associated with a reduction in the
amyloid plaque burden and a decrease of a neurodegenerative biomarker in
AD brains, forming the basis of a novel pathway approach to therapy for
AD.
P4-446 TREATMENT OF MICE WITH TYROSINE KINASE
INHIBITORS (TKI) SUCH AS GLEEVEC LOWERS
PLASMA LEVELS OFAMYLOID BETA PEPTIDES
(ABETA) IN MICE
Marc Weksler1, Paul Szabo1, Antonia Coppus2, Marcus Reidenberg1,
Pankaj Mehta3, Richard Silver1, Norman Relkin1, Babette Weksler1, 1Weill
Cornell Medical College, New York, New York, United States; 2Erasmus
University Medical Center, Rotterdam, Netherlands; 3Institute for Basic
Research, Staten Island, New York, United States.
Background:Considerable evidence exists that increased levels of Abeta
peptides (Abeta) augment the risk of Alzheimer’s disease (AD). Imati-
nib, a tyrosine inhibitor (TKI), has been shown in mice to decrease
synthesis of Abeta in vitro and in vivo although it poorly crosses the
blood-brain barrier. Recently, JG Sutcliffe suggested that cerebral levels
of Abeta are regulated in peripheral tissues. If TKI decreased Abeta pro-
duction in humans and lowered its plasma levels it might complement
the therapeutic efficacy of intravenous immunoglobulin (IVIg) now be-
ing studied in AD. Methods: Levels of Abeta40 and Abeta42 were mea-
sured in coded plasma samples from patients with chronic myeloid
leukemia (CML) treated with or without TKI and from healthy age-
matched individuals not receiving TKI. Plasma was frozen at -80C until
assayed using a sensitive ELISA with high avidity rabbit monoclonal an-
tibodies specific for Abeta40 or Abeta42. Results: Plasma Abeta peptide
levels were measured in 10 bcr-abl+ CML patients in cytogenetic remis-
sion and 1 bcr-abl+ ALL patient in remission treated with TKIs for one
to 9 years. Mean plasma Abeta40 in this group was 176 +/- 50 pg/ml
and mean Abeta42 74 +/- 41 pg/ml. These values were significantly lower
(p < 0.011, two-tailed rank-sum test) than in 3 plasmas CML patients not
treated with TKI (mean Abeta40 344 +/- 32; mean Abeta42, 204 +/- 40 pg/
ml). Plasma Abeta peptides in the 11 TKI-treated patients were also signif-
icantly lower (p < 0.048) than in 6 healthy individuals not receiving TKIs
(mean Abeta40, 258 +/- 45 and mean Abeta42, 125 +/- 47 pg/ml).Conclu-
sions: Patients with bcr-abl+ disease treated with TKIs for as long as 9
years had significantly lower plasma levels of Abeta40 and Abeta42
than CML patients not receiving TKI or normal individuals. This is the first
report that TKI therapy in humans is associated with a reduction in plasma
levels in Abeta 40 and Abeta 42. Our data imply that adding TKIs to other
therapies for AD such as IVIg might offer a uniquely effective pairing of
drugs, one clearing Abeta from the brain and another inhibiting Abeta syn-
thesis in AD patients.
P4-447 CONFORMATION DIRECTED
IMMUNOMODULATION TARGETING AMYLOID
PLAQUES, CAA AND NEUROFIBRILLARY
TANGLE PATHOLOGY IN MODEL MICE
Fernando Goni, Henrieta Scholtzova, Kinlung Wong, Yanjie Sun,
Jason Pan, Jialin Li, Yong Ji, Thomas Wisniewski, New York University
School of Medicine, New York, New York, United States.