RESUMO
Beta-amyloid (Aß) immunotherapy is a promising intervention to slow Alzheimer's disease. Aging dogs naturally accumulate Aß and show cognitive decline. An active vaccine against fibrillar Aß 1-42 (VAC) in aged beagles resulted in maintenance but not improvement of cognition along with reduced brain Aß. Behavioral enrichment (ENR) led to cognitive benefits but no reduction in Aß. We hypothesized cognitive outcomes could be improved by combining VAC with ENR in aged dogs. Aged dogs (11-12 years) were placed into 4 groups: (1) control/control (C/C); (2) control/VAC (C/V); (3) ENR/control (E/C); and (4) ENR/VAC (E/V) and treated for 20 months. VAC decreased brain Aß, pyroglutamate Aß, increased cerebrospinal fluid Aß 42 and brain-derived neurotrophic factor RNA levels but also increased microhemorrhages. ENR reduced brain Aß and prevented microhemorrhages. The combination treatment resulted in a significant maintenance of learning over time, reduced Aß, and increased brain-derived neurotrophic factor mRNA despite increased microhemorrhages; however, there were no benefits to memory. These results suggest that the combination of immunotherapy with behavioral enrichment leads to cognitive maintenance associated with reduced neuropathology that may benefit people with Alzheimer's disease.
Assuntos
Envelhecimento/metabolismo , Envelhecimento/psicologia , Doença de Alzheimer/terapia , Vacinas contra Alzheimer/uso terapêutico , Peptídeos beta-Amiloides/imunologia , Peptídeos beta-Amiloides/metabolismo , Hemorragia Cerebral/prevenção & controle , Cognição , Terapia Cognitivo-Comportamental/métodos , Imunoterapia , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/etiologia , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Cães , Desamparo Aprendido , Fragmentos de Peptídeos/líquido cefalorraquidiano , RNA Mensageiro/metabolismoRESUMO
Alzheimer's disease (AD) involves multiple pathological processes in the brain, including increased inflammation and oxidative damage, as well as the accumulation of amyloid-ß (Aß) plaques. We hypothesized that a combinatorial therapeutic approach to target these multiple pathways may provide cognitive and neuropathological benefits for AD patients. To test this hypothesis, we used a canine model of human aging and AD. Aged dogs naturally develop learning and memory impairments, human-type Aß deposits, and oxidative damage in the brain. Thus, 9 aged beagles (98-115 months) were treated with a medical food cocktail containing (1) an extract of turmeric containing 95% curcuminoids; (2) an extract of green tea containing 50% epigallocatechingallate; (3) N-acetyl cysteine; (4) R-alpha lipoic acid; and (5) an extract of black pepper containing 95% piperine. Nine similarly aged dogs served as placebo-treated controls. After 3 months of treatment, 13 dogs completed a variable distance landmark task used as a measure of spatial attention. As compared to placebo-treated animals, dogs receiving the medical food cocktail had significantly lower error scores (t11 = 4.3, p = 0.001) and were more accurate across all distances (F(1,9) = 20.7, p = 0.001), suggesting an overall improvement in spatial attention. Measures of visual discrimination learning, executive function and spatial memory, and levels of brain and cerebrospinal fluid Aß were unaffected by the cocktail. Our results indicate that this medical food cocktail may be beneficial for improving spatial attention and motivation deficits associated with impaired cognition in aging and AD.