The Effects of Exercise Training on the Brain-Derived Neurotrophic Factor (BDNF) in the Patients with Type 2 Diabetes: A Systematic Review of the Randomized Controlled Trials

The Impact of Exercise Training on the Brain and Cognition in Type 2 Diabetes, and its Physiological Mediators: A Systematic Review

BACKGROUND

Type 2 diabetes (T2DM) affects brain structure and function, and is associated with an increased risk of dementia and mild cognitive impairment. It is known that exercise training has a beneficial effect on cognition and brain structure and function, at least in healthy people, but the impact of exercise training on these aspects remains to be fully elucidated in patients with T2DM.

OBJECTIVE

To determine the impact of exercise training on cognition and brain structure and function in T2DM, and identify the involved physiological mediators.

METHODS

This paper systematically reviews studies that evaluate the effect of exercise training on cognition in T2DM, and aims to indicate the most beneficial exercise modality for improving or preserving cognition in this patient group. In addition, the possible physiological mediators and targets involved in these improvements are narratively described in the second part of this review. Papers published up until the 14th of January 2025 were searched by means of the electronic databases PubMed, Embase, and Web of Science. Studies directly investigating the effect of any kind of exercise training on the brain or cognition in patients with T2DM, or animal models thereof, were included, with the exception of human studies assessing cognition only at one time point, and studies combining exercise training with other interventions (e.g. dietary changes, cognitive training, etc.). Study quality was assessed by means of the TESTEX tool for human studies, and the CAMARADES tool for animal studies.

RESULTS

For the systematic part of the review, 22 papers were found to be eligible. 18 out of 22 papers (81.8%) showed a significant positive effect of exercise training on cognition in T2DM, of which two studies only showed significant improvements in the minority of the cognitive tests. Four papers (18.2%) could not find a significant effect of exercise on cognition in T2DM. Resistance and endurance exercise were found to be equally effective for achieving cognitive improvement. Machine-based power training is seemingly more effective than resistance training with body weight and elastic bands to reach cognitive improvement. In addition, BDNF, lactate, leptin, adiponectin, GSK3β, GLP-1, the AMPK/SIRT1 pathway, and the PI3K/Akt pathway were identified as plausible mediators directly from studies investigating the effect of exercise training on brain structure and function in T2DM. Via these mediators, exercise training induces multiple beneficial brain changes, such as increased neuroplasticity, increased insulin sensitivity, and decreased inflammation.

CONCLUSION

Overall, exercise training beneficially affects cognition and brain structure and function in T2DM, with resistance and endurance exercise having similar effects. However, there is a need for additional studies, and more methodological consistency between different studies in order to define an exercise program optimal for improving cognition in T2DM. Furthermore, we were able to define several mediators involved in the effect of exercise training on cognition in T2DM, but further research is necessary to unravel the entire process.

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.

Aerobic exercise training improves memory function through modulation of brain-derived neurotrophic factor and synaptic proteins in the hippocampus and prefrontal cortex of type 2 diabetic rats

Aims/Introduction

Defective insulin signaling in the brain may disrupt hippocampal neuroplasticity resulting in learning and memory impairments. Thus, this study investigated the effect of aerobic exercise training on cognitive function and synaptic protein markers in diabetic rats.

Materials and methods

Twenty male Wistar rats (200-250 g), were fed on high-fat diet and received a low dose of streptozotocin (35 mg/kg, i.p) to induce type 2 diabetes. Then diabetic animals were randomly divided into sedentary and training groups. The exercise training program was treadmill running at 27 m/min for 60 min/day for 8 weeks. One day after the last training session, Morris Water Maze (MWM) task was performed to evaluate spatial learning and memory. Then, the hippocamp and prefrontal cortex tissues were instantly dissected for immunoblotting assay of BDNF, GSK-3β, p-GSK-3β, P38, p-P38, ERK1/2, p-ERK1/2, heat shock protein-27 (HSP27), SNAP-25, synaptophysin, and PSD-95. Independent t-test analysis and two-way ANOVA was used to determine the differences under significance level of 0.05 using the 26th version of IBM SPSS statistical software.

Results

The results showed that aerobic exercise improved memory as assessed in the MWM task. Moreover, aerobic exercise up-regulated HSP27 and BDNF protein levels in the prefrontal cortex, and hippocampus coincided with robust elevations in SNAP25 and PSD-95 levels. Moreover, exercise reduced phosphorylated P38, while increased p-ERK1/2 and p-GSK-3β (p).

Conclusion

Our findings suggest that aerobic exercise may debilitate the harmful effects of diabetes on the cognitive function possibly through enhancing synaptic protein markers.

Qigong Training Effects on Brain-Derived Neurotrophic Factor and Cognitive Functions in Sedentary Middle-Aged and Elderly Females With Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) heightens dementia and cognitive decline risk, notably impacting working memory and executive functions. This study investigates the impact of 8 weeks of qigong training on cognitive functions, blood pressure, plasma brain-derived neurotrophic factor (pBDNF), antioxidant, and biochemical outcomes in sedentary middle-aged and elderly women with T2DM. Thirty-five sedentary middle-aged and elderly women with T2DM were assigned to qigong exercise (QG = 19) or control (CG = 16) groups. Qigong exercise group performed the qigong exercise three times per week, for 8 weeks. The cognitive functions and pBDNF as primary and secondary outcomes (blood pressure parameters, antioxidant, and blood cell indices) were measured at baseline and postexercise training. While cognitive performance did not change, there was a significant interaction (Group × Time), indicating reduced pBDNF levels postintervention in the qigong exercise group (p < .05). Both mean arterial blood and pulse pressure values decreased after qigong training (p < .05), but no significant interaction effects (Time × Group) were seen. There was a pulse pressure reduction after qigong training (p < .05), which was significantly correlated with the increase in longest digit span forward (r = −.34, p < .05). Antioxidant levels decreased from PRE to POST within both groups. This study demonstrated that 8 weeks of qigong training reduced pBDNF levels in sedentary middle-aged and elderly women with T2DM, which is unrelated to cognitive function improvements but possibly indicating a favorable response to exercise. Additionally, reduced blood and pulse pressure, potentially enhancing cognitive function by favorably impacting the autonomic nervous system by qigong training.

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.

Molecular Study of the Protective Effect of a Low-Carbohydrate, High-Fat Diet against Brain Insulin Resistance in an Animal Model of Metabolic Syndrome

Brain insulin resistance is linked to metabolic syndrome (MetS). A low-carbohydrate, high-fat (LCHF) diet has been proposed to have a protective effect. Therefore, this study aimed to investigate the brain insulin resistance markers in a rat animal model of MetS and the protective effects of the LCHF diet. Four groups of male rats (10/group) were created. Group I (Control) was fed a regular diet. Groups II-IV were injected with dexamethasone (DEX) to induce MetS. Group II received DEX with a regular diet. Group III (DEX + LCHF) rates were fed a low-carbohydrate, high-fat diet, while Group IV (DEX + HCLF) rats were fed a high-carbohydrate, low-fat (HCLF) diet. At the end of the four-week experiment, HOMA-IR was calculated. Moreover, cerebral gene expression analysis of S-100B, BDNF, TNF-α, IGF-1, IGF-1 R, IGFBP-2, IGFBP-5, Bax, Bcl-2, and caspase-3 was carried out. In the DEX group, rats showed a significant increase in the HOMA-IR and a decrease in the gene expression of IGF-1, IGF-1 R, IGFBP-2, IGFBP-5, BDNF, and Bcl2, with a concomitant rise in S100B, TNF-α, Bax, and caspase-3. The LCHF diet group showed a significantly opposite effect on all parameters. In conclusion, MetS is associated with dysregulated cerebral gene expression of BDNF, S100B, and TNF-α and disturbed IGF-1 signaling, with increased apoptosis and neuroinflammation. Moreover, the LCHF diet showed a protective effect, as evidenced by preservation of the investigated biochemical and molecular parameters.

Exploring the effects of physical exercise on inferiority feeling in children and adolescents with disabilities: a test of chain mediated effects of self-depletion and self-efficacy

Objective

The purpose of this study was to investigate the effects of physical exercise on inferiority feeling of children and adolescents with disabilities and its mechanism of action, as well as the mediating role of self depletion and self-efficacy.

Methods

The following scales were administered to 546 children and adolescents with disabilities (mean age 15.6 years): The Feelings of Inadequacy Scale, (FIS), the Self-Regulation Fatigue Scale (S-RFS), the General Self-Efficacy Scale (GSES), and the Physical Exercise Rating Scale.

Results

(1) Physical exercise can directly and negatively predict inferiority feeling, self-depletion, and can directly and positively predict self-efficacy; self-depletion can directly and negatively predict self-efficacy. Similarly, self-depletion positively predicts inferiority feeling; physical exercise and self-efficacy can also directly and negatively predict inferiority feeling. (2) The indirect effect of the path with self-depletion as the mediating variable was - 0.05, the indirect effect of the path with self-efficacy as the mediating variable was - 0.09, and the indirect effect of the path with self-depletion and self-efficacy as the mediating variables was - 0.04. (3) The sum of all indirect effects was - 0.18, and the three indirect effects accounted for 15.6%, 28.1%, and 12.5% of the total effect, with mediating effect was 56.2%.

Conclusion

Physical exercise can indirectly predict inferiority feeling in children and adolescents with disabilities through the independent mediation of self-depletion and self-efficacy, as well as through the chain mediation of both. This study supports that moderate physical exercise has a positive effect on the mental health of children and adolescents with disabilities, and that reducing self-depletion and improving self-efficacy are important ways to prevent inferiority feeling among children and adolescents with disabilities. It reveals the relationship between physical exercise and inferiority feeling and its mechanism of action, and further improves the research on the effect of physical exercise on inferiority feeling of children and adolescents with disabilities.

Physical activity in a swimming pool attenuates memory impairment by reducing glutamate and inflammatory cytokines and increasing BDNF in the brain of mice with type 2 diabetes

Type 2 diabetes is a risk factor for the development of cognitive impairment. Increasing evidence suggests that regular exercise is beneficial for the treatment of clinical symptoms in diabetic patients. The current study aimed to evaluate whether increasing physical activity through swimming training can reduce memory impairment in an animal model of type 2 diabetes. Diabetes and non-diabetes mice underwent swimming training for four weeks, and then working, spatial, and recognition memory were evaluated using three behavioral tests. Body weight, glucose, and insulin resistance were monitored. We also measured inflammatory cytokines (interleukin (IL)- 6, IL-1β, and tumor-necrosis-factor (TNF)-α), an anti-inflammatory cytokine (IL-10), and brain-derived-neurotrophic-factor (BDNF), and glutamate levels in the hippocampus or prefrontal cortex of mice. The findings showed that diabetes increased body weight, glucose, and insulin resistance, impaired working, spatial and recognition memory, increased levels of IL-6, IL-1β, TNF-α, and glutamate levels, and decreased BDNF in the hippocampus of diabetic mice. While higher physical activity was associated with reduced body weight, glucose, and insulin resistance, attenuated memory impairment, IL-6, IL-1β, TNF-α, and glutamate, and increased BDNF levels in the hippocampus and prefrontal cortex of diabetic mice. This study shows that swimming training can normalize body weight and glucose-insulin axis and reduce inflammation and glutamate in the hippocampus and enhance the neurotrophic system in both the hippocampus and prefrontal cortex of diabetic mice. This study also suggests that higher physical activity through swimming training can improve cognitive impairment in a mouse model of type 2 diabetes.

Combined Ursolic Acid and Resistance/Endurance Training Improve Type 3 Diabetes Biomarkers-Related Memory Deficits in Hippocampus of Aged Male Wistar Rats

Background

Both aging and diabetes are two well-established risk factors related to type 3 diabetes and memory deficits. Accordingly, diabetes multiplies the effects of aging on cognition impairments once these conditions occur simultaneously.

Methods

In this present experimental study, 56 male Wistar rats with HFD/STZ-induced T2D were randomized into seven groups (n = eight animals per group): (1) sedentary old non-diabetic (C); (2) sedentary HFD/STZ-induced T2D (D); (3) sedentary HFD/STZ-induced T2D plus UA (UA) (DU); (4) endurance-trained HFD/STZ-induced T2D (DE); (5) resistance-trained HFD/STZ-induced T2D (DR); (6) endurance-trained HFD/STZ-induced T2D plus UA (DEU); and (7) resistance-trained STZ-diabetic plus UA (DRU) rats. Two-way ANOVA was applied to measure the training, supplementation, and interaction effect on serum and gene expression outcomes.

Result

The study results established no significant interaction effect between the UA supplementation and the resistance/endurance training with regard to the levels of glucose (P = 0.534), insulin (P = 0.327), brain-derived neurotrophic factor (P = 0.191), and insulin-like growth factor-1 (P = 0.448).

Conclusions

To develop novel practical nutritional strategies involving UA intake, further studies are thus needed to clarify how chronic consumption of UA with/without resistance/endurance training reverses cognition disorder process in old male Wistar rats with HFD/STZ-induced T2D.

Perceptions and responses to cognitive decline in people with diabetes: A systematic review of qualitative studies

Objective

We aimed at summarizing the perceptions and responses to cognitive decline, assessing the disease management, identifying deficiencies and proposing new strategies for improvement in people with diabetes (PWDs).

Methods

A comprehensive search was performed in the following nine databases: PubMed, EMBASE, Web of Science, The Cochrane Library, PsycINFO, CINAHL, WanFang, CNKI, and VIP. The Joanna Briggs Institute (JBI) Critical Appraisal Tool for qualitative research was utilized to evaluate the quality of included studies. Descriptive texts and quotations relating to patient experience were extracted from the included studies and thematically analyzed.

Results

Eight qualitative studies met the inclusion criteria and 2 overarching themes were identified: (1) self-perception of cognitive decline referred to perceived cognitive symptoms, lack of knowledge and, impaired self-management and coping in multiple methods; (2) reported benefits of cognitive interventions referred to how cognitive interventions improved disease management, attitudes and needs of PWDs.

Conclusion

PWDs described misconceptions about their cognitive decline and suffered from them during disease management. This study provides a patient-specific reference for cognitive screening and intervention in PWDs, supporting disease management with cognitive decline in clinical practice.

Brain-Derived Neurotrophic Factor And Coronary Artery Disease

Coronary artery disease (CAD) is defined as myocardial damage developing as a result of its organic and functional changes, and leading to impaired blood flow through the coronary arteries. An important pathogenetic component of CAD is atherosclerosis. Currently, key aspects of the molecular relationship between inflammation and atherosclerosis are being actively studied, the immunometabolic theory of atherosclerosis is being discussed, along with an involvement of perivascular adipose tissue in the pathogenesis of this pathology, due to its ability to respond to atherogenic stimuli via developing inflammatory reactions. Evidence has been accumulated that in patients with CAD, both in their blood and perivascular adipose tissue, the level of neurotrophic factors (in particular, brain-derived neurotrophic factor, BDNF) changes, which may be a promising area of research from the standpoint of studying this factor as a therapeutic target for atherosclerosis in CAD. Neurotrophic growth factors control the functioning of both immune and nervous systems, and the balance of energy metabolism and innervation of adipose tissue. They affect vascular homeostasis, and are also involved in causing and stopping inflammation. Currently, there are data on the role of BDNF in the pathogenesis of cardiovascular, neurodegenerative and metabolic diseases, and on the effect of polyunsaturated fatty acids and eicosanoids on the level of BDNF and, accordingly, the development and progression of coronary artery atherosclerosis. Our review summarizes published data (2019-2021) on the pathophysiological and pathogenetic mechanisms of the relationship between BDNF and CAD (atherosclerosis).

Square-Stepping Exercise Program Effects on Fall-Related Fitness and BDNF Levels in Older Adults in Korea: A Randomized Controlled Trial

The risk of dementia increases with age. To mitigate this risk, we examined the effect of a square-stepping exercise (SSE) program on fall-related fitness and brain-derived neurotrophic factor (BDNF) levels. Twenty older adults in Korea were randomly assigned to either the experimental or control group (each group n = 10). Participants performed SSE for 70 min per session, twice a week, for 12 weeks with a certified instructor. The average age of the participants was 74.80 ± 6.763 years in the exercise group and 72.50 ± 6.519 years in the control group. The experiment group showed significant improvement (p < 0.01) in the lower muscle strength post-intervention. The paired t-test revealed a significant improvement (p < 0.01) in the experimental group and a significant difference in the interaction effect (p < 0.01) in the BDNF levels. There was a significant improvement (p < 0.05) in the BDNF levels in the experimental group and a significant decrease (p < 0.05) in the control group. The SSE program had a positive effect on fall-related fitness and BDNF levels.

Nerve growth factor and post-infarction cardiac remodeling

The prevalence of sudden death from chronic heart failure and cardiac arrhythmias caused by myocardial infarction is a complex problem in cardiology. Post-infarction cardiac remodeling occurs after myocardial infarction. This compensatory-adaptive reaction, regulated by mechanical, neurohumoral and genetic factors, includes the structural and functional changes of cardiomyocytes, stromal elements and extracellular matrix, geometry and architectonics of the left ventricular cavity. Adverse left ventricular remodeling is associated with heart failure and increased mortality. The concept of post-infarction cardiac remodeling is an urgent problem, since the mechanisms of development and progression of adverse post-infarction changes in the myocardium are completely unexplored. In recent years, the scientist attention has been focused on neurotrophic factors involved in the sympathetic nervous system and the vascular system remodeling after myocardial infarction. Nerve growth factor (NGF) is a protein from the neurotrophin family that is essential for the survival and development of sympathetic and sensory neurons, which also plays an important role in vasculogenesis. Acute myocardial infarction and heart failure are characterized by changes in the expression and activity of neurotrophic factors and their receptors, affecting the innervation of the heart muscle, as well as having a direct effect on cardiomyocytes, endothelial and smooth muscle vascular cells. The identification of the molecular mechanisms involved in the interactions between cardiomyocytes and neurons, as well as the study of the effects of NGF in the cardiovascular system, will improve understanding of the cardiac remodeling mechanism. This review summarizes the available scientific information (2019–2021) about mechanisms of the link between post-infarction cardiac remodeling and NGF functions.

Criss-crossing autism spectrum disorder and adult neurogenesis

Autism spectrum disorder (ASD) comprises a group of multifactorial neurodevelopmental disorders primarily characterized by deficits in social interaction and repetitive behavior. Although the onset is typically in early childhood, ASD poses a lifelong challenge for both patients and caretakers. Adult neurogenesis (AN) is the process by which new functional neurons are created from neural stem cells existing in the post-natal brain. The entire event is based on a sequence of cellular processes, such as proliferation, specification of cell fate, maturation, and ultimately, synaptic integration into the existing neural circuits. Hence, AN is implicated in structural and functional brain plasticity throughout life. Accumulating evidence shows that impaired AN may underlie some of the abnormal behavioral phenotypes seen in ASD. In this review, we approach the interconnections between the molecular pathways related to AN and ASD. We also discuss existing therapeutic approaches targeting such pathways both in preclinical and clinical studies. A deeper understanding of how ASD and AN reciprocally affect one another could reveal important converging pathways leading to the emergence of psychiatric disorders.

Analysis of perceptual, psychological, and behavioral factors that affect the academic performance of education university students

The aim of this study was the effect of different perceptual, psychological, and behavioural factors in the academic performance of university students. A total of 172 students (23.5 ± 5.4 years) were recruited. Physical activity patterns, nutritional habits, personality factors, perceptions of difficulty, expected grade, grade average, and academic performance of students were analyzed. No significant differences were found in physical activity levels in relation to academic performance. Significant differences were found in the agreeableness domain in relation to higher academic performance, higher perception of healthy diet and higher body mass index values. With these results we can conclude that university student with higher academic performance were characterized by higher levels of agreeableness, perception of healthy diet and body mass index.