Circadian Disruption Reveals a Correlation of an Oxidative GSH/GSSG Redox Shift with Learning and Impaired Memory in an Alzheimer's Disease Mouse Model

It is unclear whether pre-symptomatic Alzheimer's disease (AD) causes circadian disruption or whether circadian disruption accelerates AD pathogenesis. In order to examine the sensitivity of learning and memory to circadian disruption, we altered normal lighting phases by an 8 h shortening of the dark period every 3 days (jet lag) in the APPSwDI NOS2-/- model of AD (AD-Tg) at a young age (4-5 months), when memory is not yet affected compared to non-transgenic (non-Tg) mice. Analysis of activity in 12-12 h lighting or constant darkness showed only minor differences between AD-Tg and non-Tg mice. Jet lag greatly reduced activity in both genotypes during the normal dark time. Learning on the Morris water maze was significantly impaired only in the AD-Tg mice exposed to jet lag. However, memory 3 days after training was impaired in both genotypes. Jet lag caused a decrease of glutathione (GSH) levels that tended to be more pronounced in AD-Tg than in non-Tg brains and an associated increase in NADH levels in both genotypes. Lower brain GSH levels after jet lag correlated with poor performance on the maze. These data indicate that the combination of the environmental stress of circadian disruption together with latent stress of the mutant amyloid and NOS2 knockout contributes to cognitive deficits that correlate with lower GSH levels.

Sexual history taking in the emergency department - more specificity required

BACKGROUND

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) are the most reported diseases in the United States, and emergency departments (ED) serve a population presenting with increased infection risk. However, identifying patients for whom sexually transmitted infection (STI) screening is appropriate requires accurate sexual history reporting.

STUDY OBJECTIVES

To examine the consistency with which ED patients answer general and specific sexual activity questions, and how responses relate to perceived STI risk.

METHODS

Urban ED patients aged 15-34 years completed a sexual history survey containing sexual activity and perceived infection risk questions and provided urine and pharyngeal specimens for CT/GC analysis.

RESULTS

Participants included 192 males and 301 females with a mean age of 25.2 years and were 65.7% white and 33.3% black. Thirty-eight (7.7%) were infected with CT or GC. In patients denying sexual activity in the past year (general question), 40.7% of such males and 45.0% of females also reported some form of specific sexual activity (activity misclassification). Among self-identified heterosexuals, 7.2% males and 7.5% females reported some form of homosexual activity (orientation misclassification; OM). OM individuals were more likely to perceive themselves at risk of infection both orally (odds ratio 2.92, confidence interval 1.12-7.63) and genitally (odds ratio 3.36, confidence interval 1.55-7.30).

CONCLUSIONS

Given that reported sexual activity and age are the only criteria for routine female screening, and that homosexual activity is one of the few screening criteria for males, our results show that a substantial proportion of ED patients eligible for screening may not be identified by reliance upon general sexual history questions.

Dual-energy precursor and nuclear erythroid-related factor 2 activator treatment additively improve redox glutathione levels and neuron survival in aging and Alzheimer mouse neurons upstream of reactive oxygen species

To determine whether glutathione (GSH) loss or increased reactive oxygen species (ROS) are more important to neuron loss, aging, and Alzheimer's disease (AD), we stressed or boosted GSH levels in neurons isolated from aging 3xTg-AD neurons compared with those from age-matched nontransgenic (non-Tg) neurons. Here, using titrating with buthionine sulfoximine, an inhibitor of γ-glutamyl cysteine synthetase (GCL), we observed that GSH depletion increased neuronal death of 3xTg-AD cultured neurons at increasing rates across the age span, whereas non-Tg neurons were resistant to GSH depletion until old age. Remarkably, the rate of neuron loss with ROS did not increase in old age and was the same for both genotypes, which indicates that cognitive deficits in the AD model were not caused by ROS. Therefore, we targeted for neuroprotection activation of the redox sensitive transcription factor, nuclear erythroid-related factor 2 (Nrf2) by 18 alpha glycyrrhetinic acid to stimulate GSH synthesis through GCL. This balanced stimulation of a number of redox enzymes restored the lower levels of Nrf2 and GCL seen in 3xTg-AD neurons compared with those of non-Tg neurons and promoted translocation of Nrf2 to the nucleus. By combining the Nrf2 activator together with the NADH precursor, nicotinamide, we increased neuron survival against amyloid beta stress in an additive manner. These stress tests and neuroprotective treatments suggest that the redox environment is more important for neuron survival than ROS. The dual neuroprotective treatment with nicotinamide and an Nrf2 inducer indicates that these age-related and AD-related changes are reversible.