The binding of curcumin to senile plaques (SPs) and cerebral amyloid angiopathy (CAA) was examined in the aged brain of various animal species and a human patient with Alzheimer's disease (AD), together with its binding to neurofibrillary tangles (NFTs). Brain sections were immunostained with anti-amyloid β protein 1-42 (Aβ42) and anti-amyloid β protein 1-40 (Aβ40) antibodies. These sections were also stained with alkaline Congo red, periodic acid-methenamine silver (PAM), and curcumin (0.009% curcumin solution) with or without formic acid pretreatment. The sections from the AD brain were also immunostained for anti-paired helical filament-tau (PHF-tau), and were stained with Gallyas silver for NFTs. Some SPs in the AD, monkey, dog, bear, and amyloid precursor protein transgenic mouse (APP Tg-mouse) brains contained congophilic materials, and were intensely positive for curcumin. In addition, curcumin labeled some diffuse SPs negative for Congo red in the AD, monkey, bear, and APP Tg-mouse brains. In all animals, CAA was intensely positive for both Congo red and curcumin. The specific curcumin staining activity was lost by formic acid pretreatment. In the AD brain, NFTs positive for PHF-tau and Gallyas silver were moderately stained with curcumin. These findings indicate that curcumin specifically binds to the aggregated Aβ molecules in various animals, and further to phosphorylated tau protein, probably according to its conformational nature.
"Curcumin binds to Aβ fibrils, presumably in the enol form , and stains amyloid plaques and neurofibrillary tangles in brain sections [6,7] and in vivo [8-10]. Curcumin inhibits Aβ fibril formation and promotes disaggregation of existing fibrils in vitro with IC50 values of 0.19 to 1 μM [9,11,12], although much higher IC50 values in the 10 to 12 μM range have been reported [13,14]. "
[Show abstract][Hide abstract] ABSTRACT: Introduction
Curcuminoids may improve pathological conditions associated with Alzheimer's disease. However, their therapeutic potential is limited by their exceedingly low bioavailability after oral administration. A method to deliver solubilized curcuminoids by injection was evaluated in Alzheimer transgenic mice.
Amyloid protein precursor (APP)SWE, PS1dE9 mice were intravenously or subcutaneously injected at weekly intervals between the ages of 4 and 12 months with serum- or cyclodextrin-solubilized curcuminoids to assess their potential for plaque prevention. Alternatively, mice between the ages of 11 and 12 months were intravenously injected with cyclodextrin-solubilized curcuminoids at biweekly intervals to evaluate their ability to eliminate existing plaques. Plasma and brain levels of curcuminoids and their metabolites were also determined after subcutaneous and intravenous injection.
Weekly long-term injections did not result in a significant plaque load reduction. However, intravenous injection of cyclodextrin-solubilized curcuminoids at higher curcuminoid concentrations and at a biweekly frequency between the ages of 11 and 12 months reduced the plaque load to approximately 70% of the control value. After intravenous injection, plasma levels of 100 μM curcuminoids and brain levels of 47 nmol/g could initially be achieved that declined to essentially undetectable levels within 20 minutes. The primary curcuminoid metabolites in plasma were the conjugates of glucuronide or sulfate and hexahydrocurcuminoids as reduction products. In the brain, both hexahydrocurcuminoids and octahydrocurcuminoids were detected as major metabolites. After subcutaneous injection, maximal curcuminoid plasma levels of 23 μM and brain levels of 8 nmol/g were observed at 30 minutes after injection and curcuminoids remained detectable for 2 to 3 h.
Curcuminoids are rapidly metabolized after injection and their effect on reducing plaque load associated with Alzheimer's disease may be dependent on the frequency of administration.
Alzheimer's Research and Therapy 03/2013; 5(2):16. DOI:10.1186/alzrt170 · 3.98 Impact Factor
"In a recent study, curcumin exhibited anti-inflammatory activities in osteoarthritic-affected dogs . In another study, curcumin was found to specifically bind to the aggregated Ab molecules in various animals including monkeys, dogs, and bears . In rabbits, administration of curcumin was found to reduce the contents of lipid and thiobarbituric acid reactive substances in the liver and plasma induced by pure cholesterol . "
[Show abstract][Hide abstract] ABSTRACT: Since the description by Alois Alzheimer, more than 50 years have passed during which senile dementia and pre-senile dementia have been considered Alzheimer disease (AD) on the basis of their common neuropathological and clinical manifestations. AD now covers pre-senile dementia, senile dementia, mild cognitive impairment and pre-clinical AD, all of them within the context of AD-related pathology. However, there is still a gray area between normal aging with AD-related pathology and AD. Here it is proposed that Alzheimer (or alzheimer) is an age-related neurodegenerative process distinguished from normal aging by the presence of senile plaques and neurofibrillary tangles. Alzheimer affects about 80% of individuals aged 65 years but dementia only occurs in a small percentage of individuals at this age; prevalence of dementia in Alzheimer increases to 25% in individuals aged 80 years. The concepts derived from the β-amyloid hypothesis support β-amyloid as a conductor in the pathogenesis of familial AD and as a prodding factor in sporadic AD. Moreover, seeding of β-amyloid and truncated tau explains incorporation, enhancement and perpetuation of AD-related changes. Therefore, the earliest Alzheimer changes confined to selected regions are the first grounds and the main risk factor for developing dementia. The term Alzheimer embraces this assumption and likens its meaning to other degenerative biological processes, such as atherosclerosis, that may eventually progress to disease. In this context, the first stages of Alzheimer should be considered as primary targets of therapeutic intervention in order to prevent progression to diseased states.
Progress in Neurobiology 03/2012; 97(1):38-51. DOI:10.1016/j.pneurobio.2012.03.005 · 9.99 Impact Factor
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