Journal of Alzheimer's disease : JAD
-
Alzheimer's disease (AD) is an age-dependent neurodegenerative condition that causes a progressive decline in cognitive function. Accumulation of amyloid β-protein (Aβ) in the brain is a prominent feature of AD and related disorders. However, the levels of Aβ accumulation alone are not a reliable predictor of cognitive deficits. ⋯ At 3 months of age, Tg-SwDI mice with onset of cerebral microvascular amyloid were behaviorally impaired, while the Tg-5xFAD, which had disproportionately higher levels of total Aβ, soluble oligomeric Aβ, and parenchymal amyloid were not. However, at 6 months of age, behavioral deficits for both groups of transgenic mice were evident, as the levels of Aβ pathologies in the Tg-5xFAD accumulated to extremely high amounts. The present findings suggest early-onset cerebral microvascular amyloid deposition, that precedes high parenchymal levels of Aβ, may be an important early factor in the development of cognitive deficits.
-
Rosiglitazone has been known to attenuate neurodegeneration in Alzheimer's disease (AD), but the underlying mechanisms remain to be fully elucidated. In this study, living-cell image, immunocytochemistry, and electrophysiology were used to examine the effects of soluble amyloid-β protein (Aβ) oligomers and rosiglitazone on the synapse formation, plasticity, and mitochondrial distribution in cultured neurons. Incubation of hippocampal cultures with amyloid-β (Aβ)42 oligomers (0.5 μM) for 3 h significantly decreased dendritic filopodium and synapse density. ⋯ In conclusion, our data suggested that rosiglitazone prevents Aβ42 oligomers-induced impairment via increasing mitochondrial numbers in the dendrite and spine, improving synapse formation and plasticity. This process is most likely through the PPARγ-dependent pathway and in concentration and time dependent manners. The study provides novel insights into the mechanisms for the protective effects of rosiglitzone on AD.
-
Research in Caucasian populations has begun to examine the broad associations between physical and mental health in dementia caregivers. However, the examination of this relationship in Latin America is largely absent from the literature despite the fact that the region will see a major increase in dementia cases over the next 20 years. The current study examined the associations between health-related quality of life (HRQOL) and mental health in 90 dementia caregivers from Colombia, South America. ⋯ Follow-up multiple regressions found that caregiver role limitations due to physical problems was uniquely associated with satisfaction with life, whereas vitality, role limitations due to physical problems, and pain were uniquely associated with burden (although the pain effect was likely error due to a suppressor effect). Additionally, vitality and social functioning were uniquely negatively related to depression. Because of the extremely high overlap between these two sets of variables, dementia interventions are needed in Latin America that target both caregiver mental and physical health, as both likely operate in unison and influence each other.
-
Alzheimer's disease (AD) is an age-related neurological disorder characterized by the deposition of amyloid-β (Aβ), cognitive deficits, and neuronal loss. The decline in neurogenic capacity could participate in neuronal vulnerability and contribute to memory impairment in AD. In our longitudinal study with AD model mice (5XFAD mice), we found that the number of doublecortin (neurogenesis marker)-positive cells in 5XFAD mice was significantly decreased compared to wild-type littermate mice. ⋯ We found that treatment with ghrelin increased the number of doublecortin, HH3, and calretinin-stained cells in the hippocampus of 5XFAD mice. In 5XFAD mice treated with ghrelin, the 4G8-positive area was not significantly different from the saline-treated 5XFAD mice. Together, these findings suggest that hippocampal neurogenesis is impaired in 5XFAD mice and that treatment with ghrelin successfully rescued the abnormality of neurogenesis in 5XFAD mice without affecting Aβ pathology.
-
Neurodegenerative disease is one of the greatest health crises in the world and as life expectancy rises, the number of people affected will continue to increase. The most common neurodegenerative disease, Alzheimer's disease, is a tauopathy, characterized by the presence of aggregated tau, namely in the form of neurofibrillary tangles. Historically, neurofibrillary tangles have been considered the main tau species of interest in Alzheimer's disease; however, we and others have shown that tau oligomers may be the most toxic form and the species responsible for the spread of pathology. ⋯ Additionally, we injected pure brain-derived tau oligomers intracerebrally in 3-month-old wild-type and Htau mice and treated animals with biweekly injections of 60 μg TOMA or non-specific IgG. We found that long-term administration of TOMA was effective as a preventative therapy, inhibiting oligomeric tau and preserving memory function. These results support the critical role of oligomeric tau in disease progression and validate tau oligomers as a potential drug target.