Intermittent Hypobaric Hypoxic Preconditioning Provides Neuroprotection by Increasing Antioxidant Activity, Erythropoietin Expression and Preventing Apoptosis and Astrogliosis in the Brain of Adult Rats Exposed to Acute Severe Hypoxia

Background: Exposure to intermittent hypoxia has been demonstrated to be an efficient tool for hypoxic preconditioning, preventing damage to cells and demonstrating therapeutic benefits. We aimed to evaluate the effects of respiratory intermittent hypobaric hypoxia (IHH) to avoid brain injury caused by exposure to acute severe hypoxia (ASH). Methods: biomarkers of oxidative damage, mitochondrial apoptosis, and transcriptional factors in response to hypoxia were assessed by Western blot and immunohistochemistry in brain tissue. Four groups of rats were used: (1) normoxic (NOR), (2) exposed to ASH (FiO₂ 7% for 6 h), (3) exposed to IHH for 3 h per day over 8 days at 460 mmHg, and (4) ASH preconditioned after IHH. Results: ASH animals underwent increased oxidative-stress-related parameters, an upregulation in apoptotic proteins and had astrocytes with phenotype forms compatible with severe diffuse reactive astrogliosis. These effects were attenuated and even prevented when the animals were preconditioned with IHH. These changes paralleled the inhibition of NF-κB expression and the increase of erythropoietin (EPO) levels in the brain. Conclusions: IHH exerted neuroprotection against ASH-induced oxidative injury by preventing oxidative stress and inhibiting the apoptotic cascade, which was associated with NF-κB downregulation and EPO upregulation.

Optimal Cutoff Scores for Dementia and Mild Cognitive Impairment in the Brazilian Version of the Montreal Cognitive Assessment among the Elderly

Objective

To propose cutoff scores for the Brazilian version of the Montreal Cognitive Assessment (MoCA-BR) stratified by education in order to detect mild cognitive impairment (MCI) and mild Alzheimer's disease (AD) in the elderly.

Method

A transversal study in health centers was performed on 159 elderly people with 4–12 years of education and 70 of their peers with over 12 years of schooling. The MoCA-BR cutoff scores for screening cognitive impairment were determined based on an ROC curve analysis.

Results

The ROC curve analysis indicated that cutoff scores under 20 were good for screening elderly people with cognitive impairment with more than 12 years of education, and scores under 21 were good for screening those with 4–12 years of education.

Conclusions

MoCA-BR scores under 21 points (after adding 1 point to the elderly with ≤12 years of education) indicate a need to continue the diagnostic investigation with regular follow-ups.

Influence of Age and Education on the Performance of Elderly in the Brazilian Version of the Montreal Cognitive Assessment Battery

AIMS

To provide normative data for the Brazilian version of the Montreal Cognitive Assessment (MoCA-BR) and to measure the effect of sociodemographic variables on the cognitive performance of cognitively healthy elderly people.

METHODS

A sample of 110 cognitively healthy individuals, aged over 65 years, with at least 4 years of schooling were recruited from 3 health care centers for the elderly in Recife, Brazil. The cognitive performance was assessed using MoCA-BR.

RESULTS

The average score of these elderly people in the MoCA-BR was 23.2 ± 2.7. Their schooling correlated positively with the cognitive performance, with a Spearman's coefficient of 0.33 (p < 0.001). There was a statistically significant negative correlation between age and the cognitive performance (Spearman's rho = -0.19). The multiple linear regression model with the highest adjusted coefficient of determination was the one that included schooling and age (adjusted R2 = 0.127).

CONCLUSIONS

The cognitive performance of healthy elderly was evaluated and was strongly influenced by schooling and, to a lower degree, by age.