Neurobiology of aging
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Neurobiology of aging · Mar 2010
Randomized Controlled TrialIs age a key determinant of mortality and neurological outcome after acute traumatic spinal cord injury?
Given the potential impact of age on mortality, neurological outcomes and the extent of post-traumatic neural degeneration, we examined these issues using a large, prospectively accrued clinical database (n=485) supplemented by analysis of postmortem spinal cord tissue (n=12) to compare axonal survival and white matter degeneration in younger versus elderly individuals with spinal cord injury (SCI). Elderly individuals (> or = 65 years) had significantly greater mortality rates than younger individuals at 30 days, at 6 months and at 1 year following SCI (46.88% versus 4.86%, respectively; p<0.0001). ⋯ Correspondingly, neuroanatomical analysis of postmortem spinal cord tissue revealed no significant age-related differences for extent of myelin degeneration or number of intact axons within sensory, motor and autonomic spinal cord tracts post-SCI. Treatment protocols for SCI need to identify preventable predictors of mortality in the elderly post-SCI, recognizing that the potential for neurological recovery among elderly survivors of SCI is similar to that of younger individuals.
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Neurobiology of aging · Mar 2010
Diffusion tensor imaging of deep gray matter brain structures: effects of age and iron concentration.
Diffusion tensor imaging (DTI) of the brain has become a mainstay in the study of normal aging of white matter, and only recently has attention turned to the use of DTI to examine aging effects in gray matter structures. Of the many changes in the brain that occur with advancing age is increased presence of iron, notable in selective deep gray matter structures. In vivo detection and measurement of iron deposition is possible with magnetic resonance imaging (MRI) because of iron's effect on signal intensity. ⋯ Signal intensity measured with DWI was lower in the putamen of elderly than young adults, whereas the opposite was observed for the white matter region and thalamus. As a retrospective study based on legacy data, the FDRI estimates were based on FSE sequences, which underestimated the classical FDRI index of brain iron. Nonetheless, the differential effects of age on DTI metrics in subcortical gray matter structures compared with white matter tracts appears to be related, at least in part, to local iron content, which in the elderly of the present study was prominent in the FDRI estimate of the putamen and visibly striking in the diffusion-weighted image of the basal ganglia structures.
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Neurobiology of aging · Jan 2010
A novel anti-inflammatory role of NCAM-derived mimetic peptide, FGL.
Age-related cognitive deficits in hippocampus are correlated with neuroinflammatory changes, typified by increased pro-inflammatory cytokine production and microglial activation. We provide evidence that the neural cell adhesion molecule (NCAM)-derived mimetic peptide, FG loop (FGL), acts as a novel anti-inflammatory agent. Administration of FGL to aged rats attenuated the increased expression of markers of activated microglia, the increase in pro-inflammatory interleukin-1beta (IL-1beta) and the impairment in long-term potentiation (LTP). ⋯ We demonstrate that FGL enhanced interleukin-4 (IL-4) release from glial cells and IL-4 in turn enhanced neuronal CD200 in vitro. We provide evidence that the increase in CD200 is reliant on IL-4-induced extracellular signal-regulated kinase (ERK) signal transduction. These findings provide the first evidence of a role for FGL as an anti-inflammatory agent and identify a mechanism by which FGL controls microglial activation.
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Neurobiology of aging · Jan 2010
Vascular risk factors and dementia in the general population aged >85 years: prospective population-based study.
The aim of this study was to evaluate the association between dementia and common vascular risk factors including blood pressure, blood lipids, homocysteine and diabetes mellitus in a population of very old people. This study is a 9-year follow-up prospective population-based study monitoring 339 non-demented subjects aged 85 years or over in the city of Vantaa, Southern Finland. ⋯ It seems that the contribution of vascular risk factors to the risk of dementia may be age-dependent and their role in the very old subjects may be mediated through their influence on cerebrovascular morbidity. Thus, prevention of stroke and diabetes mellitus may reduce the risk of cognitive decline in the very old.
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Neurobiology of aging · Mar 2009
Review Meta AnalysisBlood-brain barrier: ageing and microvascular disease--systematic review and meta-analysis.
Cerebral "microvascular" disease occurs in lacunar stroke, leukoaraiosis, vascular dementia and Alzheimer's disease. It may arise from or contribute to insidious damage to the blood-brain barrier (BBB). We systematically reviewed the literature for evidence that BBB permeability is altered in patients with manifestations of cerebral microvascular disease. ⋯ D. 0.60, 99% CI 0.30, 0.89, p<0.01). BBB permeability increases with normal ageing and may be an important mechanism in the initiation or worsening of cerebral microvascular disease. Further studies on the role of BBB permeability are urgently needed.