Transcriptomic changes in the prefrontal cortex of rats as a function of age and cognitive engagement

Cognitive trajectories in longitudinally trained 3xTg-AD mice

Preclinical studies in Alzheimer's disease (AD) often rely on cognitively naïve animal models in cross-sectional designs that can fail to reflect the cognitive exposures across the lifespan and heterogeneous neurobehavioral features observed in humans. To determine whether longitudinal cognitive training may affect cognitive capacities in a well-characterized AD mouse model, 3xTg and wild-type mice (n = 20) were exposed daily to a training variant of the Go-No-Go (GNG) operant task from 3 to 9 months old. At 3, 6, and 9 months, performance on a testing variant of the GNG task and anxiety-like behaviors were measured, while long-term recognition memory was also assessed at 9 months. In general, GNG training improved performance with increasing age across genotypes. At 3 months old, 3xTg mice showed slight deficits in inhibitory control that were accompanied by minor improvements in signal detection and decreased anxiety-like behavior, but these differences did not persist at 6 and 9 months old. At 9 months old, 3xTg mice displayed minor deficits in signal detection, and long-term recognition memory capacity was comparable with wild-type subjects. Our findings indicate that longitudinal cognitive training can render 3xTg mice with cognitive capacities that are on par with their wild-type counterparts, potentially reflecting functional compensation in subjects harboring AD genetic mutations.

Sex Differentially Alters Secretion of Brain Extracellular Vesicles During Aging: A Potential Mechanism for Maintaining Brain Homeostasis

Extracellular vesicles (EVs) in the brain play a role in neuronal homeostasis by removing intracellular material and regulating cell-to-cell communication. Given that sex and aging differentially modulate brain networks, we investigated sex-dependent differences in EV levels and content in the brain during aging. EVs were isolated from the brains of 3, 6, 12, 18, and 24 month-old female and male C57BL/6 J mice, and the levels of different EV species determined. While the number of plasma membrane-derived microvesicles and a subset of late endosomes-derived exosomes increased with age in the brain of female mice, no significant changes were seen in males. Mitochondria-derived mitovesicles in the brain increased during aging in both sexes, a change that may reflect aging-dependent alterations in mitochondrial function. These findings reveal enhanced turnover during aging in female brains, suggesting a mechanism for advantageous successful female brain aging and sex-depending different susceptibility to age-related neurodegenerative diseases.

Exosomes in Age-Related Cognitive Decline: Mechanistic Insights and Improving Outcomes

Aging is the most prominent risk factor for cognitive decline, yet behavioral symptomology and underlying neurobiology can vary between individuals. Certain individuals exhibit significant age-related cognitive impairments, while others maintain intact cognitive functioning with only minimal decline. Recent developments in genomic, proteomic, and functional imaging approaches have provided insights into the molecular and cellular substrates of cognitive decline in age-related neuropathologies. Despite the emergence of novel tools, accurately and reliably predicting longitudinal cognitive trajectories and improving functional outcomes for the elderly remains a major challenge. One promising approach has been the use of exosomes, a subgroup of extracellular vesicles that regulate intercellular communication and are easily accessible compared to other approaches. In the current review, we highlight recent findings which illustrate how the analysis of exosomes can improve our understanding of the underlying neurobiological mechanisms that contribute to cognitive variation in aging. Specifically, we focus on exosome-mediated regulation of miRNAs, neuroinflammation, and aggregate-prone proteins. In addition, we discuss how exosomes might be used to enhance individual patient outcomes by serving as reliable biomarkers of cognitive decline and as nanocarriers to deliver therapeutic agents to the brain in neurodegenerative conditions.

Microglia and modifiable life factors: Potential contributions to cognitive resilience in aging

Given the increasing prevalence of age-related cognitive decline, it is relevant to consider the factors and mechanisms that might facilitate an individual's resiliency to such deficits. Growing evidence suggests a preeminent role of microglia, the prime mediator of innate immunity within the central nervous system. Human and animal investigations suggest aberrant microglial functioning and neuroinflammation are not only characteristic of the aged brain, but also might contribute to age-related dementia and Alzheimer's Disease. Conversely, accumulating data suggest that modifiable lifestyle factors (MLFs), such as healthy diet, exercise and cognitive engagement, can reliably afford cognitive benefits by potentially suppressing inflammation in the aging brain. The present review highlights recent advances in our understanding of the role for microglia in maintaining brain homeostasis and cognitive functioning in aging. Moreover, we propose an integrated, mechanistic model that postulates an individual's resiliency to cognitive decline afforded by MLFs might be mediated by the mitigation of aberrant microglia activation in aging, and subsequent suppression of neuroinflammation.

Typological features of the brain in normal conditions and in cerebral hypoperfusion

Relevance. Stress resistance and cognitive abilities of the patient, forming the personal component of the rehabilitation potential, have a significant impact on the course and recovery period after cerebral hypoxia of various origins. The adaptation of rehabilitation measures to the individual characteristics of the patient will significantly increase the effectiveness of rehabilitation measures for stroke and neurodegenerative diseases. The aim of this work is to generalize experimental and clinical studies characterizing the influence of individual characteristics of higher nervous activity on the course of cerebral hypoperfusion. Materials and methods . The study of literary sources of scientometric scientific bases for the last 15 years has been carried out. Results . The level of stress resistance is based on alternative biochemical strategies of neuronal metabolism of macroergs and neurotransmitters. At the organismic level, this is realized in a greater base voltage of the stress-activating system and a smaller reserve capacity of the sympathoadrenal system. In general, this leads to more severe cerebral hypoperfusion in stress-resistant individuals and slower recovery and is correlated with a high baseline sympathetic nervous system tone, insulin and testosterone concentrations. At the same time, a low level of stress resistance determines a greater sensitivity to exogenous corrective influences in cerebral hypoperfusion. The level of cognitive ability is associated with astrocytic responses and the organization of synaptic ensembles. The participation of astrocytes in the regulation of glutamate levels probably has a combined effect on both the state of cognitive mechanisms and damage to the components of neuroglial assemblies during hypoxia. This is also due to the release of S100 +, which, in turn, enhances the coordinated oscillations of neurons in the medial prefrontal cortex and hippocampus and may be the cause of greater damage to the cells of the cerebral hemispheres of the brain in animals with a high level of cognitive abilities in the cerebral hypoperfusion model.

Transcriptomic Analysis of Fuzi Lizhong Decoction for the Treatment of Stomach Ulcers

This study aims to understand the treatment of stomach ulcers with FLD and to identify its potential target genes as well as related pathways by transcriptomic analysis. Rat stomach mRNA from a blank group (BG), a model group (MG), an untreated-model group (u-MG), and a treated group (TG) was sequenced. A partial least-squares discriminant analysis (PLS-DA) was used to differentiate the MG from the BG, and the Deseq2 R Package was used to identify differentially expressed genes between these groups. Furthermore, t-tests based on transcripts per million (TPM) were used to select different genes between MG and BG and significantly retrieved genes in TG, except for self-retrieved genes in u-MG. Finally, pathways regulated by retrieved genes were analyzed with KEGG database. Results showed that 327 of the 32,623 total detected genes were different (p < 0.05) between the MG and BG. Among these genes, eighteen genes were significantly retrieved after rats were treated with FLD in TG, and they were considered as target genes on which FLD acted. In conclusion, FLD was deduced to cure stomach ulcers by affecting glycerolipid metabolism, fatty acid degradation, circadian entrainment, circadian rhythm, and dopaminergic synapse.