Partial restoration of choline acetyltransferase activities in aging and AF64A-lesioned rat brains by vitamin E

Long-term intake of vegetables and fruits and subjective cognitive function in US men

OBJECTIVE

To evaluate the prospective association of long-term intake of vegetables and fruits with late-life subjective cognitive function (SCF).

METHODS

Among 27,842 men with a mean age of 51 years in 1986, we used multinomial logistic regression to examine the relation of vegetable and fruit consumption to future SCF. Average dietary intake was calculated from 5 repeated food frequency questionnaires collected every 4 years until 2002. SCF score was assessed twice (2008 and 2012) using a 6-item questionnaire; validity was supported by strong associations with APO ε4 genotype. We categorized the average of the 2 scores as good, moderate, and poor SCF.

RESULTS

Higher intakes of total vegetables, total fruits, and fruit juice were each significantly associated with lower odds of moderate or poor SCF after controlling for major nondietary factors and total energy intake. The association with total fruit intake was weaker after further adjusting for major dietary factors. In this model, the multivariate odds ratios (95% confidence intervals) for vegetable intake (top vs bottom quintile) were 0.83 (0.76-0.92), p trend <0.001 for moderate SCF and 0.66 (0.55-0.80), p trend <0.001 for poor SCF. For orange juice, compared to <1 serving/mo of intake, daily consumption was associated with a substantially lower odds of poor SCF (0.53 [0.43-0.67], p trend <0.001). Higher consumption of vegetables and fruits 18 to 22 years before SCF assessment was associated with lower odds of poor SCF independent of more proximal intake.

CONCLUSION

Our findings support a long-term beneficial role of vegetable, fruit, and orange juice consumption on SCF.

Increased Consumption of Fruit and Vegetables Is Related to a Reduced Risk of Cognitive Impairment and Dementia: Meta-Analysis

Background: Increased consumption of fruit and vegetables has been shown to be associated with a reduced risk of cognitive impairment and dementia in many epidemiological studies. The purpose of this study was to assess the strength of this association in a meta-analysis.

Methods: We identified relevant studies by searching Medline, Embase, and Cochrane Library electronic databases (from 1970 to January 2016). Study were included if they reported relative risks and corresponding 95% confidence intervals (CIs) of cognitive impairment and dementia with respect to frequency of fruit and vegetable intake.

Results: Nine studies (five cohort studies and four cross-sectional studies) met the inclusion criteria and were included in the meta-analysis. There were a total of 31,104 participants and 4,583 incident cases of cognitive impairment and dementia. The meta-analysis showed that an increased consumption of fruit and vegetables was associated with a significant reduction in the risk of cognitive impairment and dementia (OR = 0.80, 95% CI 0.71–0.89). Subgroup analysis indicated this inverse association was only found among participants with mean age over 65 years and combined sexes. Dose–response meta-analysis showed that an increment of 100 g per day of fruit and vegetable consumption was related to an approximately 13% (OR = 0.87, 95% CI 0.77–0.99) reduction in cognitive impairment and dementia risk. There was no potential publication bias in the meta-analysis and the dose–response meta-analysis.

Conclusion: The increased consumption of fruit and vegetables is associated with a reduced risk of cognitive impairment and dementia.

Fruit and vegetable consumption and cognitive decline in aging women

We prospectively examined fruit and vegetable intake in relation to cognitive function and decline among aging women. Participants were followed from in 1976 with biennial questionnaires, and food frequency questionnaires were administered in 1984, 1986, and every 4 years thereafter. From 1995 to 2001, we administered, by telephone, six cognitive tests measuring general cognition, verbal memory, category fluency, and working memory. We repeated assessments two years later for 13,388 women (>90% follow-up). We averaged dietary intakes from 1984 through the first cognitive assessment, and used linear regression to obtain multivariable-adjusted mean differences in performance and decline in performance across intake levels. Fruits were not associated with cognition or cognitive decline. However, total vegetable intake was significantly associated with less decline. Specifically, on a global score combining all tests, women in the highest quintile of cruciferous vegetables declined slower (by 0.04 unit; 95% confidence interval, 0.003, 0.07; p trend = 0.1) compared with the lowest quintile. Women consuming the most green leafy vegetables also experienced slower decline than women consuming the least amount (by 0.05 unit; 95% confidence interval, 0.02, 0.09; p trend < 0.001). These mean differences were equivalent to those observed for women about 1 to 2 years apart in age.

Protection against inflammatory neurodegeneration and glial cell death by 7β-hydroxy epiandrosterone, a novel neurosteroid

It has been demonstrated that neuroprotective effects of dehydroepiandrosterone (DHEA) may be mediated by its 7alpha- and 7beta-hydroxy derivatives. Epiandrosterone is also converted to 7beta-hydroxy epiandrosterone (7beta-OH EPIA) in numerous tissues. The aim of the present study was to establish whether treatment with 7beta-hydroxy epiandrosterone has a neuroprotective effect in animal models of Alzheimer's disease (AD) lesions. Intra-amygdaloid administration of amyloid beta [Abeta(25-35)] increased the number of tau-positive cells in the ipsilateral hippocampus. Intracerebroventricular administration of ethylcholine aziridinium (AF64A) caused cholinergic damage in the septum, and glial lesions in the lateral septal nucleus and in the lateral zones of the hippocampus. These effects were almost completely prevented when animals were treated subcutaneously (b.i.d.) for 10 days with 0.1 mg/kg 7beta-hydroxy epiandrosterone. These findings indicate that 7beta-hydroxy epiandrosterone has powerful cytoprotective effects suggesting that (a) this neurosteroid may have therapeutic potential in various neurodegenerative conditions such as Alzheimer's disease, and (b) 7beta-hydroxy steroids may constitute a novel class of endogenous neuroprotective agents.

High-dose antioxidant supplements and cognitive function in community-dwelling elderly women

BACKGROUND

Experimental data suggest that oxygen free radicals are probably involved in the deterioration of cognitive processes.

OBJECTIVE

Our objective was to investigate the relation of high-dose antioxidant supplements to cognition.

DESIGN

Information on the use of specific supplements containing vitamins E and C was collected biennially via mailed questionnaires beginning in 1980 from 14 968 community-dwelling women who participated in the Nurses' Health Study. From 1995 to 2000, telephone tests of cognitive function [Telephone Interview of Cognitive Status (TICS), delayed recall of the TICS 10-word list, immediate and delayed recall of a short paragraph, a test of verbal fluency, and a digit span backwards test] were administered to the women, who were 70-79 y of age at that time. We used linear and logistic regression models to calculate multivariate-adjusted mean differences in test scores and relative risks of a low score for specific supplement users compared with nonusers.

RESULTS

Long-term, current users of vitamin E with vitamin C had significantly better mean performance, as judged by a global score that combined individual test scores, than did women who had never used vitamin E or C (P = 0.03); there was a trend for increasingly higher mean scores with increasing durations of use (P = 0.04). These associations were strongest among women with low dietary intakes of alpha-tocopherol. Benefits were less consistent for women taking vitamin E alone, with no evidence of higher scores with longer durations of use. Use of specific vitamin C supplements alone had little relation to performance on our cognitive tests.

CONCLUSION

The use of specific vitamin E supplements, but not specific vitamin C supplements, may be related to modest cognitive benefits in older women.

Arecoline via miniosmotic pump improves AF64A-impaired radial maze performance in rats: a possible model of Alzheimer's disease

Male Sprague-Dawley rats, preoperatively trained in a 1-h delay non-match-to-position radial maze task, received bilateral stereotaxic injections of a selective cholinotoxin, ethylcholine aziridinium ion (AF64A: 3 nmol/3 microliters/lateral ventricle). Animals treated with AF64A made significantly more total postdelay errors than vehicle controls. Sustained delivery, via miniosmotic pumps, of arecoline (0.1, 0.3, 1, 3, 10, or 30 mg/kg/day sc for 14 days) attenuated the AF64A-induced cognitive impairment in a dose-dependent manner, producing an inverted U-shaped dose-response function which was optimal at 1.0 mg/kg/day. Following these studies, choline acetyltransferase activity was significantly reduced in hippocampi extracted from the AF64A-treated rats, indicating successful cholinotoxicity. This paradigm may be useful as a possible screen for potential Alzheimer's disease therapeutic agents. This conclusion is supported by published reports of beneficial arecoline effects observed following 2-week intravenous infusions in patients with Alzheimer's disease (Soncrant, Raffaele, Asthana, Berardi, Morris, & Haxby, 1993).

The AF64A model of cholinergic hypofunction: an update

Based on numerous reports in the literature since 1980, one can now conclude that ethylcholine aziridinium (AF64A) is selective for the cholinergic system in vivo, and that the effect is both dose- and site-dependent. Thus, AF64A treatment, under the correct conditions of dose and time will result in selective reductions in levels of ACh, AChE, ChAT, HAChT, and K(+)- and ouabain-stimulated release of ACh. While other neurotransmitters may also be affected in brains of AF64A treated rats, the effect is only transient and is most probably secondary to the initial cholinergic deficit-induced by AF64A, reflecting an adaptive reaction of these neurotransmitter systems, which are normally integrated with cholinergic interconnections, to the cholinergic deficiency induced by AF64A. This paper provides a historical perspective for the development of AF64A as a selective cholinotoxin, and surveys its potential mechanisms of action at the neurochemical and molecular levels. Moreover, the availability of an animal model such as the AF64A-treated rat, in which the cholinergic system has been compromised selectively for an extended period of time, has allowed investigators to study a wide variety of questions that relate to factors controlling cholinergic function in vivo. Several key illustrations are presented at the end of this paper.

Tolcapone, an inhibitor of catechol O-methyltransferase, counteracts memory deficits caused by bilateral cholinotoxin lesions of the basal nuclei of Meynert

Repeated administration of tolcapone, an inhibitor of catechol-O-methyltransferase, was able to partially restore the memory deficits caused by bilateral cholinotoxin (AF64A) lesions in the basal magnocellular nuclei of Meynert. The 2-week tolcapone treatment (3 mg kg-1, once a day) was started 24 h before toxin infusion and the last injection was given 24 h before the first avoidance test. The beneficial action of tolcapone may be related to antioxidant properties of nitrocatechols.