Swimming Suppresses Cognitive Decline of HFD-Induced Obese Mice through Reversing Hippocampal Inflammation, Insulin Resistance, and BDNF Level

Effects of exercise interventions on brain-derived neurotrophic factor levels in overweight and obesity: A systematic review and meta-analysis

Background

/Objective. An explosion in global obesity epidemic poses threats to the healthcare system by provoking risks of many debilitating diseases, including cognitive dysfunction. Physical activity has been shown to alleviate the deleterious effects of obesity-associated cognitive deficits across the lifespan. Given the strong neuroprotective role of brain-derived neurotrophic factor (BDNF) and exercise training as a known modulator for its elevation, this systematic review sought to examine the strength of the association between exercise and BDNF levels in healthy people with overweight and obesity.

Methods

Six electronic databases (PubMed, MEDLINE, EMBASE, Web of Science, Ovid Nursing Database, and SPORTDiscus) were searched from their inceptions through December 2022. The primary outcome of interest was BDNF levels. Interventional studies (randomized and quasi-experimental) with English full text available were included. Risk of bias of the included studies was assessed using the Physiotherapy Evidence Database Scale. Data were extracted for meta-analyses by random-effects models.

Results

Thirteen studies (n = 750), of which 69.2% (9/13) had low risk of bias, were included. In the meta-analysis, exercise interventions had no significant effect on resting BDNF levels (standardized mean difference: -0.30, 95% CI -0.80 to 0.21, P = 0.25). Subgroup analyses also indicated no effects of age and types of control groups being compared on moderating the association.

Conclusion

To further inform the role of BDNF in obesity-related cognitive functioning, rigorous studies with larger samples of participants and raw data available were imperatively deserved.

Potential molecular mechanism of exercise reversing insulin resistance and improving neurodegenerative diseases

Neurodegenerative diseases are debilitating nervous system disorders attributed to various conditions such as body aging, gene mutations, genetic factors, and immune system disorders. Prominent neurodegenerative diseases include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis. Insulin resistance refers to the inability of the peripheral and central tissues of the body to respond to insulin and effectively regulate blood sugar levels. Insulin resistance has been observed in various neurodegenerative diseases and has been suggested to induce the occurrence, development, and exacerbation of neurodegenerative diseases. Furthermore, an increasing number of studies have suggested that reversing insulin resistance may be a critical intervention for the treatment of neurodegenerative diseases. Among the numerous measures available to improve insulin sensitivity, exercise is a widely accepted strategy due to its convenience, affordability, and significant impact on increasing insulin sensitivity. This review examines the association between neurodegenerative diseases and insulin resistance and highlights the molecular mechanisms by which exercise can reverse insulin resistance under these conditions. The focus was on regulating insulin resistance through exercise and providing practical ideas and suggestions for future research focused on exercise-induced insulin sensitivity in the context of neurodegenerative diseases.

Effect of exercise interventions on brain-derived neurotrophic factor expression in people with overweight and obesity: protocol for a systematic review and meta-analysis

INTRODUCTION

Epidemic obesity ('globobesity') has led to a considerable rise in the prevalence and incidence of many disabling conditions, including cognitive dysfunction. Recent evidence has suggested that habitual exercise can alleviate the deleterious effects of obesity on cognitive functioning across the lifespan. Given that there is a potential link among obesity, exercise, cognitive health and brain-derived neurotrophic factor (BDNF), this systematic review aims to critically appraise interventional trials on exercise and BDNF and to estimate the pooled effect of exercise training on BDNF levels among healthy individuals with overweight and obesity.

METHODS AND ANALYSIS

Six electronic databases-PubMed, MEDLINE, EMBASE, Web of Science, Ovid Nursing Database and SPORTDiscus-will be searched from their inception through December 2022. Only interventional studies, including randomised controlled trials and quasi-experimental studies, with full text available and reported in English will be included. The primary outcomes will be changes in BDNF levels among healthy subjects with overweight and obesity following either acute or chronic bouts of exercise interventions. Two reviewers will independently conduct data extraction and risk of bias assessment for included trials using the Physiotherapy Evidence Database Scale. We will produce a narrative synthesis, with findings categorised by sex, age groups and types of exercise training. Data will be extracted and pooled for meta-analyses using random-effects models.

ETHICS AND DISSEMINATION

No formal ethical approval is required for this systematic review. The findings of this review will be disseminated through peer-reviewed publications.

PROSPERO REGISTRATION NUMBER

CRD42023414868.

New Insights into High-Fat Diet with Chronic Diseases

Chronic diseases, encompassing conditions such as heart disease, cancer, and diabetes, represent a significant global health challenge and are the leading causes of mortality worldwide [...].

Roles of prokineticin 2 in electroconvulsive shock-induced memory impairment via regulation of phenotype polarization in astrocytes

Electroconvulsive shock (ECT) is the most effective treatment for depression but can impair learning and memory. ECT is increasingly being shown to activate astrocytes and induce neuroinflammation, resulting in cognitive decline. Activated astrocytes can differentiate into two subtypes, A1-type astrocytes and A2-type astrocytes. Regarding cognitive function, neurotoxic A1 astrocytes and neuroprotective A2 astrocytes may exhibit opposite effects. Specifically, prokineticin 2 (PK2) functions as an essential mediator of inflammation and induces a selective A2-protective phenotype in astrocytes. This study aimed to clarify how PK2 promotes improved learning memory following electroconvulsive shock (ECS). As part of the study, rats were modeled using chronic unpredictable mild stress. Behavioral experiments were conducted to assess their cognitive abilities and depression-like behaviors. Western blot was used to determine the expression of PK2. Immunohistochemical and electron microscopy analyses of the hippocampal CA1 region were conducted to study the activation of astrocyte subtypes and synaptic ultrastructure, respectively. In this study, rats' spatial learning and memory impairment began to improve as activated A1-subtype astrocytes gradually decreased, and PK2 and A2 phenotype activation peaked on the third day after ECS. PKRA7 (PK2 antagonist) inhibits A2-type astrocyte activation partially and suppresses spatial learning and memory improvement. Collectively, our findings support that PK2 may induce a selective modulation of astrocytic polarization to a protective phenotype to promote learning and memory improvement after ECS.