Acetylcholinesterase inhibitors in Alzheimer's disease influence Zinc and Copper homeostasis.

BACKGROUND: Alzheimer's disease (AD) is the most common age-related neurodegenerative disease. An altered homeostasis of Zinc (Zn) and Copper (Cu), as well as a dysregulated expression of Zn-regulatory proteins have been previously described in AD. Acetylcholinesterase inhibitors (AChEI) are commonly used as AD treatment to improve cognitive function, but their effect on Zn homeostasis is still unexplored. OBJECTIVES: The aims of this study were to define the metal dyshomeostasis in AD patients, to investigate AChEI influence on Zn homeostasis and inflammation, and to analyze the relationship between cognitive impairment at two-year follow-up and metal concentrations, considering AChEI use. METHODS AND RESULTS: 84 Healthy Elderly (HE) and 95 AD patients were enrolled (62 AchEI user and 33 AchEI naïve). HE showed similar plasma Zn and Cu concentrations and Cu/Zn ratio in comparison to AChEI users, but significantly higher Zn level, as well as lower Cu amount and Cu/Zn ratio than AChEI naïve patients. Moreover, AChEI users had increased Zn plasma level, reduced Cu amount, Cu/Zn ratio, and IL1ß concentration and lower Zip2 lymphocytic expression vs. naïve patients. A multiple linear regression analysis showed that the MMSE score decline after two-year follow-up was reduced by AChEI therapy and was positively associated with plasma Zn decrease over time. CONCLUSION: Our data revealed that AChEI use may affect peripheral Zn and Cu homeostasis in AD patients, decrease Cu/Zn ratio demonstrating a general reduction of inflammatory status in patients under AChEI treatment. Finally, AChEI influence on circulating Zn could be implicated in the drug-related slowdown of cognitive decline.

My Mind Project: the effects of cognitive training for elderly-the study protocol of a prospective randomized intervention study.

BACKGROUND: Cognitive decline and dementia represent a key problem for public health as they heavily impair social functioning and independent living. The development of new strategies to support recommendations for patients and their caregivers may represent an outstanding step forward. AIMS: To describe the study protocol and methods of "My Mind Project: the effect of cognitive training for elderly" (Grant No. 154/GR-2009-1584108), which investigates, by the use of a multidisciplinary approach, the effects of a comprehensive cognitive training programme on performances in aged subjects with mild-moderate Alzheimer's disease, mild cognitive impairment and normal cognitive functioning. METHODS: The study is a prospective randomized intervention for the assessment of cognitive training effects in three groups of elderly subjects with different cognitive status. A total of 321 elderly people were enrolled in Marche Region, Italy. Each subject was randomly assigned to an experimental group or to a control group. Cognitive performances and biochemical blood markers have also been analysed before cognitive training (baseline), immediately after termination (follow-up 1), after 6 months (follow-up 2) and after 2 years (follow-up 3). DISCUSSION: The results will be useful to identify some efficient programmes for the enhancement of cognitive performance in elderly with and without cognitive decline. CONCLUSION: The application of a non-pharmacological approach in the treatment of elderly with cognitive disorders could have a profound impact on National Health Service.

Forced mild physical training improves blood volume in the motor and hippocampal cortex of old mice.

OBJECTIVES: To assess the effect of mild forced physical training on cerebral blood volume (CBV) and other brain parameters in old mice. SETTING: Treadmill in the animal house. PARTICIPANTS: Thirty old (>25 mo) male mice were randomly assigned to one of three groups, exercise (E), exercise plus testosterone (T) (ET), and rest (C). INTERVENTION: Mild physical training on treadmill (30 min a day at belt speed = 8 m/min, five days a week) with or without one weekly injection of testosterone. MEASUREMENTS: CBV, quantitative transverse relaxation time (T2) maps, and cortical thickness were measured by magnetic resonance imaging. RESULTS: A significant increase of CBV was found in the motor and hippocampal cortex of E and ET mice; cortical thickness was not affected. T2 maps analysis suggested that water distribution did not change. T administration did not add to the effect of physical training. CONCLUSION: This work provides first quantitative evidence that exercise initiated at old age is able to improve the hemodynamic status of the brain cortex in key regions for movement and cognition without inducing edema.

Discovering pathways of sarcopenia in older adults: a role for insulin resistance on mitochondria dysfunction.

The precise cause of sarcopenia, skeletal muscle loss and strength, in older persons is unknown. However, there is a strong evidence for muscle loss due to insulin resistance as well as mitochondrial dysfunction over aging. Considering that epidemiological studies have underlined that insulin resistance may have a specific role on skeletal muscle fibre atrophy and mitochondrial dysfunction has also been extensively shown to have a pivotal role on muscle loss in older persons, a combined pathway may not be ruled out. Considering that there is growing evidence for an insulin-related pathway on mitochondrial signaling, we hypothesize that a high degree of insulin resistance will be associated with the development of sarcopenia through specific alterations on mitochondrial functioning. This paper will highlight recent reviews regarding the link between skeletal muscle mitochondrial dysfunction and insulin resistance. We will specifically emphasize possible steps involved in sarcopenia over aging, including potential biomolecular mechanisms of insulin resistance on mitochondrial functioning.

Decreased numeric density of succinic dehydrogenase-positive mitochondria in CA1 pyramidal neurons of 3xTg-AD mice.

Alzheimer disease (AD) is associated with mitochondrial dysfunction. In this study, we investigated succinic dehydrogenase (SDH) activity in mitochondria of hippocampal CA1 pyramidal neurons obtained from 10-month-old 3xTg-AD mice, an animal model of AD, as well as from age-matched control mice PS1-KI. In SDH-positive mitochondria, we measured numeric density (Nv, number of mitochondria/microm(3) of cytoplasm), average organelle volume (V), volume density (Vv, volume fraction of mitochondria/microm(3) of cytoplasm), average length (Fmax), and the ratio (R) between the total area of the cytochemical precipitate due to SDH activity and the total mitochondrial area. Our results indicate that 3xTg-AD mitochondria show a significant decrease of Nv, increase in V and Fmax, as well as a trend toward a reduction of R, whereas Vv is unchanged. Our findings further support the idea that mitochondrial dysfunction is involved in AD and are in line with studies indicating that both amyloid precursor protein (APP) and amyloid-beta (Abeta) localize to mitochondria.

Structural synaptic remodeling in the perirhinal cortex of adult and old rats following object-recognition visual training.

The ultrastructural features of layer II synapses in the perirhinal cortex of adult (4- to 6-month-old) and old (25- to 27-month-old) rats exposed to a six-session object recognition visual training were investigated by morphometric methods. The comparative analysis showed a higher synaptic numeric density, a lower synaptic average area, and a lower percentage of megasynapses (S > 0.5 microm2) in old trained rats versus controls, and a higher percentage of small (S < 0.15 microm2) junctions in adult trained rats versus controls. The more marked synaptic remodeling underlying memory consolidation in the perirhinal cortex of old rats might reflect a pre-existing lower dynamic status.

Transthyretin inhibition of amyloid beta aggregation and toxicity.

OBJECTIVES: The aim of this study was to investigate transthyretin (prealbumin) effects on Abeta25-35-induced cytotoxicity. DESIGN AND METHODS: In view of the well-recognized literature data demonstrating that Abeta25-35 fibrillar aggregates cause in vitro cytotoxicity to human red blood cells and apoptotic changes to SK-N-BE neuroblastoma cells in cultures (ultrastructural evidence), we tested transthyretin effects on these two experimental models. RESULTS: Incubation of Abeta25-35 with transthyretin (at transthyretin concentrations equal to CSF physiological levels) demonstrated both inhibition of red blood cells lysis and neutralization of SK-N-BE neuroblastoma cells ultrastructural apoptotic changes. Moreover, transthyretin was shown to be able to inhibit the formation of fibrillar macroaggregates of Abeta25-35. CONCLUSIONS: The findings imply that experimental systems investigating Abeta-induced cytotoxicity consider the protective interaction of transthyretin with Abeta; an interaction to be considered also in vivo in view of the fact that transthyretin immunoreactivity has been previously demonstrated in amyloid plaques of brains from Alzheimer's disease patients.

Ethanol-induced decrease of the expression of glucose transport protein (Glut3) in the central nervous system as a predisposing condition to apoptosis: the effect of age.

We measured the effect of chronic ethanol administration on the expression of Glut3 in the cerebellum and hippocampus of adult and old rats. Glut3 expression significantly decreased in aging, in ethanol-treated rats vs. age-matched controls, and in adult- vs. old ethanol-treated rats. These findings lend consistent support to the hypothesis that disturbances of glucose metabolism due to ethanol may constitute an unfavorable condition predisposing to neuronal death.