Long-term exercise training improves memory in middle-aged men and modulates peripheral levels of BDNF and Cathepsin B

The effects of exercise interventions on brain-derived neurotrophic factor levels in children and adolescents: a meta-analysis

Brain-derived neurotrophic factor is a crucial neurotrophic factor that plays a significant role in brain health. Although the vast majority of meta-analyses have confirmed that exercise interventions can increase brain-derived neurotrophic factor levels in children and adolescents, the effects of specific types of exercise on brain-derived neurotrophic factor levels are still controversial. To address this issue, we used meta-analytic methods to quantitatively evaluate, analyze, and integrate relevant studies. Our goals were to formulate general conclusions regarding the use of exercise interventions, explore the physiological mechanisms by which exercise improves brain health and cognitive ability in children and adolescents, and provide a reliable foundation for follow-up research. We used the PubMed, Web of Science, Science Direct, Springer, Wiley Online Library, Weipu, Wanfang, and China National Knowledge Infrastructure databases to search for randomized controlled trials examining the influences of exercise interventions on brain-derived neurotrophic factor levels in children and adolescents. The extracted data were analyzed using ReviewManager 5.3. According to the inclusion criteria, we assessed randomized controlled trials in which the samples were mainly children and adolescents, and the outcome indicators were measured before and after the intervention. We excluded animal experiments, studies that lacked a control group, and those that did not report quantitative results. The mean difference (MD; before versus after intervention) was used to evaluate the effect of exercise on brain-derived neurotrophic factor levels in children and adolescents. Overall, 531 participants (60 children and 471 adolescents, 10.9-16.1 years) were included from 13 randomized controlled trials. Heterogeneity was evaluated using the Q statistic and I2 test provided by ReviewManager software. The meta-analysis showed that there was no heterogeneity among the studies (P = 0.67, I2 = 0.00%). The combined effect of the interventions was significant (MD = 2.88, 95% CI: 1.53-4.22, P < 0.0001), indicating that the brain-derived neurotrophic factor levels of the children and adolescents in the exercise group were significantly higher than those in the control group. In conclusion, different types of exercise interventions significantly increased brain-derived neurotrophic factor levels in children and adolescents. However, because of the small sample size of this meta-analysis, more high-quality research is needed to verify our conclusions. This meta-analysis was registered at PROSPERO (registration ID: CRD42023439408).

Role of astrocytes in Alzheimer's disease pathogenesis and the impact of exercise-induced remodeling

Alzheimer's disease (AD) is a prevalent and debilitating brain disorder that worsens progressively with age, characterized by cognitive decline and memory impairment. The accumulation of amyloid-beta (Aβ) leading to amyloid plaques and hyperphosphorylation of Tau, resulting in intracellular neurofibrillary tangles (NFTs), are primary pathological features of AD. Despite significant research investment and effort, therapies targeting Aβ and NFTs have proven limited in efficacy for treating or slowing AD progression. Consequently, there is a growing interest in non-invasive therapeutic strategies for AD prevention. Exercise, a low-cost and non-invasive intervention, has demonstrated promising neuroprotective potential in AD prevention. Astrocytes, among the most abundant glial cells in the brain, play essential roles in various physiological processes and are implicated in AD initiation and progression. Exercise delays pathological progression and mitigates cognitive dysfunction in AD by modulating astrocyte morphological and phenotypic changes and fostering crosstalk with other glial cells. This review aims to consolidate the current understanding of how exercise influences astrocyte dynamics in AD, with a focus on elucidating the molecular and cellular mechanisms underlying astrocyte remodeling. The review begins with an overview of the neuropathological changes observed in AD, followed by an examination of astrocyte dysfunction as a feature of the disease. Lastly, the review explores the potential therapeutic implications of exercise-induced astrocyte remodeling in the context of AD.

Moderate-intensity aerobic exercise enhanced dopamine signaling in diet-induced obese female mice without preventing body weight gain

Obesity continues to rise in prevalence and financial burden despite strong evidence linking it to an increased risk of developing several chronic diseases. Dopamine response and receptor density are shown to decrease under conditions of obesity. However, it is unclear if this could be a potential mechanism for treatment without drugs that have a potential for abuse. Therefore, the aim of this study was to investigate whether moderate-intensity exercise could reduce body weight gain and the associated decreases in dopamine signaling observed with high-fat diet-induced adiposity. We hypothesized that exercise would attenuate body weight gain and diet-induced inflammation in high-fat (HF)-fed mice, resulting in dopamine signaling (release and reuptake rate) comparable to sedentary, low-fat (LF)-fed counterparts. This hypothesis was tested using a mouse model of diet-induced obesity (DIO) and fast-scan cyclic voltammetry to measure evoked dopamine release and reuptake rates. Although the exercise protocol employed in this study was not sufficient to prevent significant body weight gain, there was an enhancement of dopamine signaling observed in female mice fed a HF diet that underwent treadmill running. Additionally, aerobic treadmill exercise enhanced the sensitivity to amphetamine (AMPH) in this same group of exercised, HF-fed females. The estrous cycle might influence the ability of exercise to enhance dopamine signaling in females, an effect not observed in male groups. Further research into females by estrous cycle phase, in addition to determining the optimal intensity and duration of aerobic exercise, are logical next steps.

Changes in Physical Fitness, Muscle Damage and Cognitive Function in Elite Rugby Players over a Season

This study proposes to monitor the physical, immune and cognitive responses and adaptations of elite rugby players throughout the season based on the loads performed. Anthropometric measurements, physical fitness tests (e.g., muscle strength and power, linear and change-of-direction speed, cardiorespiratory fitness) and analyses of serum concentrations of markers of muscle damage (creatine kinase [CK] and lactate dehydrogenase [LDH]) and brain-derived neurotrophic factor (BDNF) were carried out over a sporting season (24 weeks) for 17 elite rugby players (10 forwards and 7 backs) aged 18.91 ± 0.76 years. The physical fitness test results show improvements in the performance of both forwards and backs over the season (p < 0.05), with an advantage for backs compared with forwards in most tests (p < 0.05). Muscle damage markers decreased at the end of the season compared with the baseline levels for forwards (p < 0.05). CK levels were unchanged for the backs, but there were increased LDH concentrations at the end of the season compared with baseline (p < 0.05). Serum BDNF levels decreased for the total group between the second and third sampling (p < 0.05). The muscular and physical capacities of rugby players differ according to their playing position. Immune responses and adaptations, as well as BDNF levels, vary throughout the season and depend on the physical load performed.

The Brain-Gut-Bone Axis in Neurodegenerative Diseases: Insights, Challenges, and Future Prospects

Neurodegenerative diseases are global health challenges characterized by the progressive degeneration of nerve cells, leading to cognitive and motor impairments. The brain-gut-bone axis, a complex network that modulates multiple physiological systems, has gained increasing attention owing to its profound effects on the occurrence and development of neurodegenerative diseases. No comprehensive review has been conducted to clarify the triangular relationship involving the brain-gut-bone axis and its potential for innovative therapies for neurodegenerative disorders. In light of this, a new perspective is aimed to propose on the interplay between the brain, gut, and bone systems, highlighting the potential of their dynamic communication in neurodegenerative diseases, as they modulate multiple physiological systems, including the nervous, immune, endocrine, and metabolic systems. Therapeutic strategies for maintaining the balance of the axis, including brain health regulation, intestinal microbiota regulation, and improving skeletal health, are also explored. The intricate physiological interactions within the brain-gut-bone axis pose a challenge in the development of effective treatments that can comprehensively target this system. Furthermore, the safety of these treatments requires further evaluation. This review offers a novel insights and strategies for the prevention and treatment of neurodegenerative diseases, which have important implications for clinical practice and patient well-being.

Effect of Aerobic Exercise versus Non-Invasive Brain Stimulation on Cognitive Function in Multiple Sclerosis: A Systematic Review and Meta-Analysis

OBJECTIVE

In this study, we investigated the effects of noninvasive brain stimulation (NIBS) and exercise on cognition in patients with multiple sclerosis (pwMS).

METHODS

A literature search was performed using the Cochrane Library, Scopus, PubMed and Web of Science. The time interval used for database construction was up to February 2024; the collected trials were subsequently screened, and the data were extracted.

RESULTS

We identified 12 studies with 208 pwMS treated with noninvasive brain stimulation. Seven of the twelve studies concluded that NIBS was effective in improving reaction time, attention and processing speed. Additionally, 26 articles investigated the effect of various types of exercise on cognition among 708 pwMS. Twelve studies used aerobic exercise only, three studies used resistance only, one used yoga, and ten studies used mixed forms of exercise, such as Pilates, resistance and Frenkel coordination. Aerobic exercise was effective in improving at least one cognitive domain in ten studies. Resistance exercise was found to improve cognition in three studies. Yoga failed to show any improvement in one study.

CONCLUSIONS

NIBS might be an effective intervention for cognition improvement among pwMS. Aerobic exercise and combined forms of exercise are the most frequently investigated and applied and found to be effective. Further studies are needed, especially for resistance, balance and stretching exercises.

Physical Exercise Inhibits Cognitive Impairment and Memory Loss in Aged Mice, and Enhances Pre- and Post-Synaptic Proteins in the Hippocampus of Young and Aged Mice

The aim of this study was to evaluate the effects of swimming in the brain and behavior of young and aged mice. Forty-eight male C57BL/6 J mice were randomly distributed into 4 groups (n = 12 per group, 3 and 18 months old). The subdivision of the groups was: 3 months-SED, 18 months-SED, 3 months-EXE, and 18 months-EXE. SED mice did not swim, while EXE mice performed the physical exercise protocol. Training was initiated 48 h after the adaptation week. Swimming sessions consisted of 30 min, with no overload, 5 days per week, for 4 weeks. After the exercise protocol, it was revealed working and spatial memory were impaired in the 18 months-SED group. Pre- and post-synaptic proteins were enhanced in the groups that swam when compared to the 3- and 8 months-SED groups. Lipid peroxidation was greater in the aged mice that did not perform the physical exercise protocol and might have contributed to the cognitive impairment in this group. In conclusion, an aerobic physical exercise protocol, performed through regular swimming sessions, inhibited cognitive impairment, memory loss and lipid peroxidation in the aged mice, while pre- and post-synaptic proteins were enhanced in the hippocampus of young and aged mice.

The Combined Effect of Tribulus terrestris Hydroalcoholic Extract and Swimming Exercise on Memory and Oxidative Stress in Old Male Rats

BACKGROUND AND OBJECTIVE

This study aims to assess the effect of swim exercise along with consumption of bindii hydroalcoholic extract on memory and the oxidative stress markers in old male rats.

MATERIALS AND METHODS

This study was conducted on 32 old (400-500 g) and eight young male Wistar rats. The groups included young, old, old bindii (200 mg/kg), old exercise, and old bindii exercise (concurrent swimming training). All interventions were performed within 14 days. The animals' spatial memory was evaluated by the Y maze, radial maze, and shuttle box, Oxidative stress factors were also measured.

RESULTS

Compared to the old control group, the bindii extract along with swimming exercise significantly increased the periodic behavior percentage in the Y maze and the delay time in entry into the dark chamber in the shuttle box but no significant difference was seen in the reference memory error in the radial maze. Also, a significant increase in the amount of catalase (CAT) and antioxidant capacity (TAC) and a significant decrease in the amount of malondialdehyde (MDA) were observed in all treatment groups.

CONCLUSION

These results show that exercise, along with the bindii extract consumption, can improve spatial and avoidance memory in old rats probably through the reduction of oxidative stress effects.

Dynamics of myelin deficits in the 5xFAD mouse model for Alzheimer's disease and the protective role of BDNF

Recent findings highlight myelin breakdown as a decisive early event in Alzheimer's Disease (AD) acting as aggravating factor of its progression. However, it is still unclear whether myelin loss is attributed to increased oligodendrocyte vulnerability, reduced repairing capacity or toxic stimuli. In the present study, we sought to clarify the starting point of myelin disruption accompanied with Oligodendrocyte Progenitor Cell (OPC) elimination in the brain of the 5xFAD mouse model of AD at 6 months of age in Dentate Gyrus of the hippocampus in relation to neurotrophin system. Prominent inflammation presence was detected since the age of 6 months playing a key role in myelin disturbance and AD progression. Expression analysis of neurotrophin receptors in OPCs was performed to identify new targets that could increase myelination in health and disease. OPCs in both control and 5xFAD mice express TrkB, TrkC and p75 receptors but not TrkA. Brain-derived neurotrophic factor (BDNF) that binds to TrkB receptor is well-known about its pro-myelination effect, promoting oligodendrocytes proliferation and differentiation, so we focused our investigation on its effects in OPCs under neurodegenerative conditions. Our in vitro results showed that BDNF rescues OPCs from death and promotes their proliferation and differentiation in presence of the toxic Amyloid-β 1-42. Collectively, our results indicate that BDNF possess an additional neuroprotective role through its actions on oligodendrocytic component and its use could be proposed as a drug-based myelin-enhancing strategy, complementary to amyloid and tau centered therapies in AD.

Changes of brain-derived neurotrophic factor (BDNF) levels after different exercise protocols: a systematic review of clinical studies in Parkinson's disease

Background: Brain-Derived Neurotrophic Factor (BDNF) serum levels are reduced in patients with Parkinson's Disease (PD). Objectives: This study aimed to assess the effect of exercise intensity, volume and type on BDNF levels in patients with PD. Methods: We searched clinicaltrials.gov, CINAHL, Embase, PubMed, Scopus, Web of Science for both controlled and non-controlled studies in patients with PD, published between 2003 and 2022, which assessed Brain-Derived Neurotrophic Factor before and after different exercise protocols. Exercise intensity was estimated using a time-weighted average of Metabolic Equivalent of Task (MET), while exercise volume was estimated by multiplying MET for the duration of exercise. Exercise types were classified as aerobic, resistance, balance and others. We computed two distinct standardized measures of effects: Hedges' g to estimate differences between experimental and control group in pre-post intervention BDNF changes, and Cohen's d to measure pre-post intervention changes in BDNF values for each study arm. Meta-regression and linear regression were used to assess whether these effect measures were associated with intensity, volume and type. PROSPERO registration number: CRD42023418629. Results: Sixteen studies (8 two-arm trials and 8 single-arm trials) including 370 patients with PD were eligible for the systematic review. Selected studies had a large variability in terms of population and intervention characteristics. The meta-analysis showed a significant improvement in BDNF levels in the exercise group compared to the control group, Hedges' g = 0.70 (95% CI: 0.03, 1.38), with substantial heterogeneity (I2 = 76.0%). Between-group differences in intensity were positively associated with change in BDNF in a subset of 5 controlled studies. In the analysis which included non-controlled studies, intensity and total exercise volume were both positively associated with BDNF change. No difference was found according to exercise type. Conclusion: Exercises of greater intensity may increase BDNF levels in patients with PD, while the role of volume of exercise needs to be further explored.

Time-resolved map of serum metabolome profiling in D-galactose-induced aging rats with exercise intervention

Exercise, an intervention with wide-ranging effects on the whole body, has been shown to delay aging. Due to aging and exercise as modulator of metabolism, a picture of how exercise delayed D-galactose (D-gal)-induced aging in a time-resolved manner was presented in this paper. The mapping of molecular changes in response to exercise has become increasingly accessible with the development of omics techniques. To explore the dynamic changes during exercise, the serum of rats and D-gal-induced aging rats before, during, and after exercise was analyzed by untargeted metabolomics. The variation of metabolites was monitored to reveal the specific response to D-gal-induced senescence and exercise in multiple pathways, especially the basal amino acid metabolism, including glycine serine and threonine metabolism, cysteine and methionine metabolism, and tryptophan metabolism. The homeostasis was disturbed by D-gal and maintained by exercise. The paper was expected to provide a theoretical basis for the study of anti-aging exercise.

Exploring the Association Between Physical Activity and Cognitive Function Among People Living with Dementia

Background

Physical activity preserves cognitive function in people without dementia, but the relationship between physical activity and cognitive domains among people living with dementia is unclear.

Objective

The objective of this study was to explore the association between physical activity and cognition domains among people living with dementia.

Methods

Participants living with dementia in residential care facilities (complete case analysis: n = 24/42) completed a battery of cognitive tests (global cognition: Montreal Cognitive Assessment; executive function: Trail-Making Test, Digit Span Forward Test; perception and orientation: Benton Judgement of Line Orientation Test; language: Boston Naming Test; learning and memory: Rey Auditory Verbal Learning Test; complex attention: Digit Symbol Substitution Test). Participants wore an actigraphy monitor on their non-dominant wrist over seven days. We conducted a linear regression for total physical activity (independent variable) with race (white/black), fall risk (Morse Fall Scale), and the number of comorbidities (Functional Comorbidities Index) as covariates, and cognitive tests as variables of interest.

Results

Participants were primarily male (75%), white (87.5%), and 50%had unspecified dementia (Alzheimer's disease: 33%). Greater physical activity was associated with poorer global cognition, better executive function, and better learning and memory (ps <  0.05). Physical activity was not related to visuospatial perception, language, or complex attention.

Conclusions

Physical activity may preserve executive function and learning and memory among people living with dementia. Wandering is more common in later stages of dementia, which may explain greater physical activity observed with lower global cognition. Regularly assessing physical activity may be useful in screening and monitoring cognitive changes.

The hormesis principle of neuroplasticity and neuroprotection

Animals live in habitats fraught with a range of environmental challenges to their bodies and brains. Accordingly, cells and organ systems have evolved stress-responsive signaling pathways that enable them to not only withstand environmental challenges but also to prepare for future challenges and function more efficiently. These phylogenetically conserved processes are the foundation of the hormesis principle, in which single or repeated exposures to low levels of environmental challenges improve cellular and organismal fitness and raise the probability of survival. Hormetic principles have been most intensively studied in physical exercise but apply to numerous other challenges known to improve human health (e.g., intermittent fasting, cognitive stimulation, and dietary phytochemicals). Here we review the physiological mechanisms underlying hormesis-based neuroplasticity and neuroprotection. Approaching natural resilience from the lens of hormesis may reveal novel methods for optimizing brain function and lowering the burden of neurological disorders.

Poor sleep versus exercise: A duel to decide whether pain resolves or persists after injury

Poor sleep is thought to enhance pain via increasing peripheral and/or central sensitization. Aerobic exercise, conversely, relives pain via reducing sensitization, among other mechanisms. This raises two clinical questions: (1) does poor sleep contribute to the transition from acute-to-persistent pain, and (2) can exercise protect against this transition? This study tested these questions and explored underlying mechanisms in a controlled injury model. Twenty-nine adult female Sprague-Dawley rats performed an intensive lever-pulling task for 4 weeks to induce symptoms consistent with clinical acute-onset overuse injury. Rats were then divided into three groups and exposed for 4 weeks to either: voluntary exercise via access to a running wheel, sleep disturbance, or both. Pain-related behaviours (forepaw mechanical sensitivity, reflexive grip strength), systemic levels of brain derived neurotrophic factor (BDNF), estradiol and corticosterone, and white blood cells (WBC) were assessed pre-injury, post-injury and post-intervention. Mechanical sensitivity increased post-injury and remained elevated with sleep disturbance alone, but decreased to pre-injury levels with exercise both with and without sleep disturbance. Reflexive grip strength decreased post-injury but recovered post-intervention-more with exercise than sleep disturbance. BDNF increased with sleep disturbance alone, remained at pre-injury levels with exercise regardless of sleep, and correlated with mechanical sensitivity. WBCs and estradiol increased with exercise alone and together with sleep disturbance, respectively. Corticosterone was not impacted by injury/intervention. Findings provide preliminary evidence for a role of poor sleep in the transition from acute-to-persistent pain, and the potential for aerobic exercise to counter these effects. BDNF might have a role in these relationships.

Effectiveness of high-intensity interval training on peripheral brain-derived neurotrophic factor in adults: A systematic review and network meta-analysis

BACKGROUND

High-intensity interval training (HIIT) has emerged as an alternative training method to increase brain-derived neurotrophic factor (BDNF) levels, a crucial molecule involved in plastic brain changes. Its effect compared to moderate-intensity continuous training (MICT) is controversial. We aimed to estimate, and to comparatively evaluate, the acute and chronic effects on peripheral BDNF levels after a HIIT, MICT intervention or a control condition in adults.

METHODS

The CINAHL, Cochrane, PubMed, PEDro, Scopus, SPORTDiscus, and Web of Science databases were searched for randomized controlled trials (RCTs) from inception to June 30, 2023. A network meta-analysis was performed to assess the acute and chronic effects of HIIT versus control condition, HIIT versus MICT and MICT versus control condition on BDNF levels. Pooled standardized mean differences (SMDs) and their 95% confidence intervals (95% CIs) were calculated for RCTs using a random-effects model.

RESULTS

A total of 22 RCTs were selected for the systematic review, with 656 participants (aged 20.4-79 years, 34.0% females) and 20 were selected for the network meta-analysis. Network SMD estimates were significant for HIIT versus control condition (1.49, 95% CI: 0.61, 2.38) and MICT versus control condition (1.08, 95% CI: 0.04, 2.12) for acutely BDNF increase. However, pairwise comparisons only resulted in a significant effect for HIIT versus control condition.

CONCLUSIONS

HIIT is the best training modality for acutely increasing peripheral BDNF levels in adults. HIIT may effectively increase BDNF levels in the long term.

Irisin/BDNF signaling in the muscle-brain axis and circadian system: A review

In mammals, the timing of physiological, biochemical and behavioral processes over a 24-h period is controlled by circadian rhythms. To entrain the master clock located in the suprachiasmatic nucleus of the hypothalamus to a precise 24-h rhythm, environmental zeitgebers are used by the circadian system. This is done primarily by signals from the retina via the retinohypothalamic tract, but other cues like exercise, feeding, temperature, anxiety, and social events have also been shown to act as non-photic zeitgebers. The recently identified myokine irisin is proposed to serve as an entraining non-photic signal of exercise. Irisin is a product of cleavage and modification from its precursor membrane fibronectin type Ⅲ domain-containing protein 5 (FNDC5) in response to exercise. Apart from well-known peripheral effects, such as inducing the "browning" of white adipocytes, irisin can penetrate the blood-brain barrier and display the effects on the brain. Experimental data suggest that FNDC5/irisin mediates the positive effects of physical activity on brain functions. In several brain areas, irisin induces the production of brain-derived neurotrophic factor (BDNF). In the master clock, a significant role in gating photic stimuli in the retinohypothalamic synapse for BDNF is suggested. However, the brain receptor for irisin remains unknown. In the current review, the interactions of physical activity and the irisin/BDNF axis with the circadian system are reconceptualized.

Probiotics supplementation and brain-derived neurotrophic factor (BDNF): a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

An emerging body of evidence has demonstrated the beneficial effects of probiotics on various mental health conditions. In this systematic review and meta-analysis, we sought to examine the effects of probiotics supplementation on brain-derived neurotrophic factor (BDNF) in adults.

METHODS

PubMed, Scopus, ISI Web of Science, and the Cochrane Library were searched, from database inception to April 2021, for eligible randomized controlled trials (RCTs). We pooled mean differences and standard deviations from RCTs using random-effect models.

RESULTS

Overall, meta-analysis of 11 trials (n = 648 participants) showed no significant changes in serum level of BDNF following probiotics. However, subgroup analysis revealed that probiotics increased BDNF levels in individuals suffering from neurological disorders (n = 214 participants; WMD = 3.08 ng/mL, 95% CI: 1.83, 4.34; P = 0.001; I2 = 7.5%; P-heterogeneity 0.34), or depression (n = 268 participants; WMD = 0.77 ng/mL, 95% CI: 0.07, 1.47; P = 0.032; I2 = 88.4%; P-heterogeneity < 0.001). Furthermore, a significant increase in BDNF levels was found in studies that administered the mixture of Lactobacillus and Bifidobacterium genera, and were conducted in Asia .

CONCLUSION

Our main findings suggest that probiotics may be effective in elevating BDNF levels in patients with depression and neurological disorders, and a mixed of Lactobacillus and Bifidobacterium appear to show greater efficacy than the single genus supplement. The low quality of evidence reduces clinical advocacy, and indicates that more large-scale, high-quality, RCTs are needed to facilitate reliable conclusions.

Greater physical fitness (Vo2Max) in healthy older adults associated with increased integrity of the Locus Coeruleus-Noradrenergic system

Physical activity (PA) is a key component for brain health and Reserve, and it is among the main dementia protective factors. However, the neurobiological mechanisms underpinning Reserve are not fully understood. In this regard, a noradrenergic (NA) theory of cognitive reserve (Robertson, 2013) has proposed that the upregulation of NA system might be a key factor for building reserve and resilience to neurodegeneration because of the neuroprotective role of NA across the brain. PA elicits an enhanced catecholamine response, in particular for NA. By increasing physical commitment, a greater amount of NA is synthetised in response to higher oxygen demand. More physically trained individuals show greater capabilities to carry oxygen resulting in greater Vo2max - a measure of oxygen uptake and physical fitness (PF). In the current study, we hypothesised that greater Vo2 max would be related to greater Locus Coeruleus (LC) MRI signal intensity. As hypothesised, greater Vo2max related to greater LC signal intensity across 41 healthy adults (age range 60-72). As a control procedure, in which these analyses were repeated for the other neuromodulators' seeds (for Serotonin, Dopamine and Acetylcholine), weaker associations emerged. This newly established link between Vo2max and LC-NA system offers further understanding of the neurobiology underpinning Reserve in relationship to PA. While this study supports Robertson's theory proposing the upregulation of the noradrenergic system as a possible key factor building Reserve, it also provide grounds for increasing LC-NA system resilience to neurodegeneration via Vo2max enhancement.

Distinct cortical haemodynamics during squat-stand and continuous aerobic exercise do not influence the magnitude of a postexercise executive function benefit

A single bout of aerobic exercise benefits executive function (EF). A potential mechanism for this benefit is an exercise-mediated increase in cerebral blood flow (CBF) that elicits vascular endothelial shear-stress improving EF efficiency. Moderate intensity continuous aerobic exercise (MCE) asymptotically increases CBF, whereas continuous body weight squat-stand exercise (SSE) provides a large amplitude oscillatory response. Some work has proposed that an increase in CBF oscillation amplitude provides the optimal shear-stress for improving EF and brain health. We examined whether a large amplitude oscillatory CBF response associated with a single bout of SSE imparts a larger postexercise EF benefit than an MCE cycle ergometer protocol. Exercise changes in middle cerebral artery velocity (MCAv) were measured via transcranial Doppler ultrasound to estimate CBF, and pre- and postexercise EF was assessed via the antisaccade task. MCE produced a steady state increase in MCAv, whereas SSE produced a large amplitude MCAv oscillation. Both conditions produced a postexercise EF benefit that null hypothesis and equivalence tests showed to be comparable in magnitude. Accordingly, we provide a first demonstration that a single bout of SSE benefits EF; however, the condition's oscillatory CBF response does not impart a larger benefit than a time- and intensity-matched MCE protocol.

Social Isolation, Loneliness, and Cognitive Performance in Older Adults: Evidence From the ELSI-Brazil Study

BACKGROUND

The association between social isolation and cognitive performance has been less investigated in low-to-middle-income countries (LMIC) and the presence of depression as a moderator on this association has not been examined. The authors examined the associations of social isolation and perceived loneliness with cognitive performance in the Brazilian Longitudinal Study of Aging.

METHODS

In this cross-sectional analysis, social isolation was evaluated by a composite score including marital status, social contact, and social support. The dependent variable was global cognitive performance, which considered memory, verbal fluency, and temporal orientation tests. Linear and logistic regressions were adjusted for sociodemographic and clinical variables. The authors added interaction terms of depressive symptoms with social isolation and loneliness to examine whether depression, measured through the Center for Epidemiologic Studies-Depression Scale, modified these associations.

RESULTS

Among 6,986 participants (mean age = 62.1 ± 9.2 years), higher levels of social connections were associated with better global cognitive performance (B = 0.02, 95%CI: 0.02; 0.04). Perceived loneliness was associated with worse cognition (B = -0.26, 95%CI = -0.34; -0.18). Interactions of depressive symptoms with social connections scores were found on memory z-score and with loneliness on global and memory z-scores, suggesting a weaker association between social isolation or loneliness and cognition among those with depressive symptoms.

CONCLUSION

In a large sample from an LMIC, social isolation and loneliness were associated with worse cognitive performance. Surprisingly, depressive symptoms decrease the strength of these associations. Future longitudinal studies are important to assess the direction of the association between social isolation and cognitive performance.

The Relationship Between Exercise, Cathepsin B, and Cognitive Functions: Systematic Review

Exercise has been shown repeatedly to improve cognitive functions. Many investigators have reported that peripheral signal molecules play an important role in regulating exercise-induced cognitive improvement. In this review we aimed to evaluate and clarify the literature to date that has focused on the relationship between Cathepsin B, cognitive functions, and exercise. We conducted a systematic review of the following databases from their inception until 10 April 2022: Pubmed, Web of Science, Scopus, Cochrane Library, Physiotherapy Evidence Database. The search strategy was comprised of ("cathepsin b") AND (exercise OR "physical activity") AND (cognit*). We followed three different quality appraisal tools to ensure the quality of the included studies. Eight studies assessing the effects of exercise on peripheral Cathepsin B levels and cognitive outcomes were included. Half of these studies indicated that exercise increased peripheral Cathepsin B levels and improved cognitive function. Further carefully designed studies focusing on the effects of exercise on peripheral Cathepsin B levels and cognitive performance are needed to better comprehend the underlying mechanisms of these relationships.

Exercise Is Medicine: How Do We Implement It?

Exercise is well known to have beneficial effects on various disease states. In this paper, we broadly describe the fundamental concepts that are shared among various disease states, including obesity, type 2 diabetes (T2D), cardiovascular disease (CVD), heart failure (HF), cancer, and psychological well-being, and the beneficial effects of exercise training within these concepts. We highlight issues involved in implementing exercise recommendations and describe the potential impacts and challenges to medical professionals and patients. Problems are identified and discussed with respect to the future roles of professionals in the current built environment with its limited infrastructure to support current physical activity recommendations.

Sleep and memory: The impact of sleep deprivation on transcription, translational control, and protein synthesis in the brain

In countries around the world, sleep deprivation represents a widespread problem affecting school-age children, teenagers, and adults. Acute sleep deprivation and more chronic sleep restriction adversely affect individual health, impairing memory and cognitive performance as well as increasing the risk and progression of numerous diseases. In mammals, the hippocampus and hippocampus-dependent memory are vulnerable to the effects of acute sleep deprivation. Sleep deprivation induces changes in molecular signaling, gene expression and may cause changes in dendritic structure in neurons. Genome wide studies have shown that acute sleep deprivation alters gene transcription, although the pool of genes affected varies between brain regions. More recently, advances in research have drawn attention to differences in gene regulation between the level of the transcriptome compared with the pool of mRNA associated with ribosomes for protein translation following sleep deprivation. Thus, in addition to transcriptional changes, sleep deprivation also affects downstream processes to alter protein translation. In this review, we focus on the multiple levels through which acute sleep deprivation impacts gene regulation, highlighting potential post-transcriptional and translational processes that may be affected by sleep deprivation. Understanding the multiple levels of gene regulation impacted by sleep deprivation is essential for future development of therapeutics that may mitigate the effects of sleep loss.

[Paracrine and endocrine functions of muscles]

BACKGROUND

Myokines discharged from working muscles are intensively researched in view of rising importance of preventive and secondary preventive effects of the autocrine, paracrine and endocrine functions.

OBJECTIVES

Recording of the current state of knowledge on the paracrine and endocrine effects of myokines and evaluation of training measures to optimize myokine concentration.

METHOD

A selective database-driven literature search was carried out on myostatin, interleukin-6 (IL-6), interleukin-15 (IL-15), irisin, cathepsin B, brain-derived neurotrophic factor (BDNF), meteorin-like and kynurenine for the period 2011 until June 2021. The paracrine and endocrine effects of the myokines are analyzed. Their release after acute physical stress and training is described.

RESULTS

IL-6 and IL-15 act in lipid metabolism and carbohydrate metabolism, IL-6 also in the brain and immune system. Irisin produces a conversion of white to brown adipose tissue ("browning"), so does meteorin-like. Cathepsin B has a central effect. Kynurenine acts indirectly via kynurenic acid in the brain. The secretion of myokines depends on the intensity of physical stress and is modified by training. Prevention of vascular and neurologic diseases, cognitive enhancement and increased immunological function can be reached by setting free myokines during physical activity. Therapeutical use by technologically modified myokines is proposed in metabolic and neurological diseases, immobilization and sarcopenia.

CONCLUSIONS

The current research situation on myokines gives reason to recommend regular muscular activity in addition to the previously evidence-based benefits of sport in order to achieve preventive and therapeutic effects.

Common Yoga Protocol Increases Peripheral Blood CD34+ Cells: An Open-Label Single-Arm Exploratory Trial

Purpose

Physical inactivity can be a cause of various lifestyle disorders including atherosclerosis, diabetes, hypertension, and cardiovascular diseases (CVDs). Lifestyle modification by the inclusion of Yoga and similar activities has shown beneficial effects on disease prevention and psychological management. However, the molecular mechanism at the cellular level is unknown. This study aims to identify the molecular response at systemic level generated after three months of Common Yoga Protocol (CYP) practice.

Methods

A total of 25 healthy adult females were recruited for this study (25 to 55 years). After the drop out of 6 participants at baseline and 2 participants after 1 month; blood samples of 17 participants were assessed. Blood samples were assessed for lipid profile, CD34+ cell enumeration and angiogenesis markers (ie, VEGF, Angiogenin and BDNF) at baseline (before intervention), after one month and after three months of Common Yoga Protocol (CYP) practice. The psychological health of the participants was assessed at baseline and after three months of CYP practice. The psychological tests used were General Health Questionnaire (GHQ), State-Trait Anxiety Inventory (STAI), Trail Making Test A & B, Digit symbol test, Digit symbol substitution test.

Results

After 3 months of intervention, blood samples of 17 participants were collected and following results were reported (1) percentage of CD34+ cells increased significantly after 3 months of CYP practice (from 18.18±7.32 cells/μL to 42.48±18.83 cells/μL) (effect size: W, 0.40; 95% CI, p = 0.001) (2) neurogenesis marker, ie, BDNF showed a significant change with time after 3 months of CYP intervention (effect size: W, 0.431, 95% CI; p = 0.002), (3) HDL showed an increasing trend (non-significant) after three months of CYP practice (53.017±1.28 mg/dl to 63.94±5.66 mg/dl) (effect size: W, 0.122; 95% CI; p = 0.126) (4) General Health score (10.64 ± 3.53 to 6.52 ± 3.12) (effect size: d, 0.98; 95% CI; p = 0.001) along with visual and executive function improved (69.94±26.21 to 61.88±28.55 (time taken in seconds)) (effect size: d, 0.582; 95% CI; p = 0.036), also stress and anxiety showed reduction (effect size: d, 0.91; 95% CI; p = 0.002) (5) a significant positive correlation was found between: HDL with VEGF (r = 0.547, p = 0.023) and BDNF (r = 0.538, p = 0.039) after 3 months of intervention; also, a significant positive correlation was found between VEGF with BDNF (r = 0.818, p ≤ 0.001) and Angiogenin (r = 0.946, p ≤ 0.001), also, BDNF was also positively correlated with Angiogenin (r = 0.725, p = 0.002) at both 1 month and 3 months after intervention. Also, VEGF and BDNF showed a significantly negative correlation with stress and anxiety questionnaire after the intervention.

Conclusion

The current study provides insights into the molecular response to CYP practice at systemic level. The results suggest that CYP practice indeed increased CD34+ cells in peripheral blood and BDNF also showed a significant change after the intervention. An overall improvement in general health and psychology of the participants was also observed.

Lower and higher volumes of physical exercise build up brain reserves against memory deficits triggered by a head injury in mice

Decreasing neurotrophic support and impaired mitochondrial bioenergetics are key mechanisms for long-term neurodegeneration and cognitive decline after traumatic brain injury (TBI). We hypothesize that preconditioning with lower and higher volumes of physical exercise upregulates the CREB-BDNF axis and bioenergetic capability, which might serve as neural reserves against cognitive impairment after severe TBI. Using a running wheel mounted in the home cage, mice were engaged in lower (LV, 48 h free access, and 48 h locked) and higher (HV, daily free access) exercise volumes for thirty days. Subsequently, LV and HV mice remained for additional thirty days in the home cage with the running wheel locked and were euthanized. The sedentary group had the running wheel always locked. For the same type of exercise stimulus in a given time, daily workout presents higher volume than alternate days workout. The total distance ran in the wheel was the reference parameter to confirm distinct exercise volumes. On average, LV exercise ran 27.522 m and HV exercise ran 52.076 m. Primarily, we investigate whether LV and HV protocols increase neurotrophic and bioenergetic support in the hippocampus thirty days after exercise ceased. Regardless of volume, exercise increased hippocampal pCREBSer133-CREB-proBDNF-BDNF signaling and mitochondrial coupling efficiency, excess capacity, and leak control, that may compose the neurobiological basis for neural reserves. Further, we challenge these neural reserves against secondary memory deficits triggered by a severe TBI. After thirty days of exercise LV and HV, and sedentary (SED) mice were submitted to the CCI model. Mice remained for additional thirty days in the home cage with the running wheel locked. The mortality after severe TBI was approximately 20% in LV and HV, while in the SED was 40%. Also, LV and HV exercise sustained hippocampal pCREBSer133-CREB-proBDNF-BDNF signaling, mitochondrial coupling efficiency, excess capacity, and leak control for thirty days after severe TBI. Corroborating these benefits, the mitochondrial H2O2 production linked to complexes I and II was attenuated by exercise regardless of the volume. These adaptations attenuated spatial learning and memory deficits caused by TBI. In summary, preconditioning with LV and HV exercise builds up long-lasting CREB-BDNF and bioenergetic neural reserves that preserve memory fitness after severe TBI.

Changes in Loneliness, BDNF, and Biological Aging Predict Trajectories in a Blood-Based Epigenetic Measure of Cortical Aging: A Study of Older Black Americans

A recent epigenetic measure of aging has developed based on human cortex tissue. This cortical clock (CC) dramatically outperformed extant blood-based epigenetic clocks in predicting brain age and neurological degeneration. Unfortunately, measures that require brain tissue are of limited utility to investigators striving to identify everyday risk factors for dementia. The present study investigated the utility of using the CpG sites included in the CC to formulate a peripheral blood-based cortical measure of brain age (CC-Bd). To establish the utility of CC-Bd, we used growth curves with individually varying time points and longitudinal data from a sample of 694 aging African Americans. We examined whether three risk factors that have been linked to cognitive decline-loneliness, depression, and BDNFm-predicted CC-Bd after controlling for several factors, including three new-generation epigenetic clocks. Our findings showed that two clocks-DunedinPACE and PoAm-predicted CC-BD, but that increases in loneliness and BDNFm continued to be robust predictors of accelerated CC-Bd even after taking these effects into account. This suggests that CC-Bd is assessing something more than the pan-tissue epigenetic clocks but that, at least in part, brain health is also associated with the general aging of the organism.

Patient-tailored transcranial direct current stimulation to improve stroke rehabilitation: study protocol of a randomized sham-controlled trial

BACKGROUND

Many patients do not fully regain motor function after ischemic stroke. Transcranial direct current stimulation (TDCS) targeting the motor cortex may improve motor outcome as an add-on intervention to physical rehabilitation. However, beneficial effects on motor function vary largely among patients within and across TDCS trials. In addition to a large heterogeneity of study designs, this variability may be caused by the fact that TDCS was given as a one-size-fits-all protocol without accounting for anatomical differences between subjects. The efficacy and consistency of TDCS might be improved by a patient-tailored design that ensures precise targeting of a physiologically relevant area with an appropriate current strength.

METHODS

In a randomized, double-blinded, sham-controlled trial, patients with subacute ischemic stroke and residual upper-extremity paresis will receive two times 20 min of focal TDCS of ipsilesional primary motor hand area (M1-HAND) during supervised rehabilitation training three times weekly for 4 weeks. Anticipated 60 patients will be randomly assigned to active or sham TDCS of ipsilesional M1-HAND, using a central anode and four equidistant cathodes. The placement of the electrode grid on the scalp and current strength at each cathode will be personalized based on individual electrical field models to induce an electrical current of 0.2 V/m in the cortical target region resulting in current strengths between 1 and 4 mA. Primary endpoint will be the difference in change of Fugl-Meyer Assessment of Upper Extremity (FMA-UE) score between active TDCS and sham at the end of the intervention. Exploratory endpoints will include UE-FMA at 12 weeks. Effects of TDCS on motor network connectivity and interhemispheric inhibition will be assessed with functional MRI and transcranial magnetic stimulation.

DISCUSSION

The study will show the feasibility and test the efficacy of personalized, multi-electrode anodal TDCS of M1-HAND in patients with subacute stroke patients with upper-extremity paresis. Concurrent multimodal brain mapping will shed light into the mechanisms of action of therapeutic personalized TDCS of M1-HAND. Together, the results from this trial may inform future personalized TDCS studies in patients with focal neurological deficits after stroke.

The effect of exercise on cognitive function in people with multiple sclerosis: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

A growing body of research examining the effect of exercise on cognitive function in people with multiple sclerosis (MS), while findings of available studies were conflicting. We aimed to explore the effect of exercise on cognitive function in MS patients.

METHODS

For this systematic review and meta-analysis, we searched PubMed, Web of Science, EBSCO, Cochrane, and Scopus electronic databases, through July 18, 2022. Cochrane risk assessment tool was used to evaluate the methodological quality of the included literature.

RESULTS

Twenty-one studies with a total of 23 experimental groups and 21 control groups met the inclusion criteria. There was a significant effect of exercise on improving cognitive function in MS patients, while the effect size was small (Cohen's d = 0.20, 95% CI 0.06-0.34, p < 0.001, I² = 39.31%). Subgroup analysis showed that exercise significantly improved memory (Cohen's d = 0.17, 95% CI 0.02-0.33, p = 0.03, I² = 7.59%). In addition, multicomponent training, exercise conducted 8 weeks and 10 weeks, up to 60 min per session, 3 times or more per week, 180 min or more per week increased cognitive function significantly. Furthermore, a worse basal MS status (defined by the Expanded Disability Status Scale) and an older age were associated with greater improvement in cognitive function.

CONCLUSION

MS patients are recommended to participate in at least three multicomponent training sessions per week, with each session lasting up to 60 min, and the exercise goal of 180 min per week can be achieved by increasing the frequency of exercise. Exercise lasting 8 or 10 weeks is best for cognitive function improvement. Additionally, a worse basal MS status, or the older the age, the greater effect on cognitive function.

Exercise improves depression through positive modulation of brain-derived neurotrophic factor (BDNF). A review based on 100 manuscripts over 20 years

The aim of this review was to explore the relevant neurobiology and the association between peripheral levels of brain-derived neurotrophic factor (BDNF) and acute and short to long-term exercise regimes, as well as its relation to depression and antidepressant treatment. A 20-year literature search was conducted. The screening process resulted in 100 manuscripts. Antidepressants as well as acute exercise, particularly high-intensity, elevates BDNF in healthy humans and clinical populations, as evidenced from aerobic and resistance-based studies. Although exercise is increasingly recognised in the management of depression, acute and short-term exercise studies have failed to establish a relationship between the severity of depression and changes in peripheral BDNF. The latter rapidly returns to baseline, possibly indicating a quick re-uptake by the brain, aiding its neuroplasticity functions. The timescale of administration needed for the antidepressants to stimulate biochemical changes is longer than similar increases with acute exercise.

Undernutrition during development modulates endoplasmic reticulum stress genes in the hippocampus of juvenile rats: Involvement of oxidative stress

To evaluate whether exercise training mitigates the deleterious effects of undernutrition during the developmental period in juvenile Wistar rats. Pregnant Wistar rats were fed with a diet containing 17 % or 8 % casein during pregnancy and lactation. At 30 days of life, male offspring were divided into 4 groups: Low-Protein non-trained (LS), Low-Protein Trained (LT), Normoprotein non-trained (NS), and Normoprotein Trained (NT). Trained rats performed aerobic exercise training (AET) for 4 weeks, 5 days a week, 1 h a day. 24 h from the last day of training, the animals were sacrificed. The tissues were removed to analyze indicators of mitochondrial metabolism, oxidative stress, and gene expression of GRP78, PERK, ATF6 ER stress markers, and BDNF. The results showed that undernutrition during development promotes deleterious effects on mitochondrial oxidative metabolism and induces reticulum stress in the hippocampus of juvenile rats. On the other hand, AET improves mitochondrial function and increases enzymatic and non-enzymatic antioxidant capacity, as well as declines ER stress. AET at moderate intensity for 4 weeks in male juvenile Wistar rats acts as a lifestyle intervention opposing the negative effects induced by a protein-restricted maternal diet.

Endurance training and MitoQ supplementation improve spatial memory, VEGF expression, and neurogenic factors in hippocampal tissue of rats

Background and Aim

The hippocampus has a key role in memory and learning, which means that this brain structure has high-energy demand. Accordingly, mitochondrial dysfunction in the hippocampus has deleterious effects on brain function. MitoQ is an antioxidant that accumulates selectively in mitochondria at high concentration. In this study, the effect of MitoQ alone and in combination with endurance training (ET) was investigated on spatial memory (distance, time, and number of passes in the target quarter), antioxidant status (superoxide dismutase [SOD] and glutathione peroxidase [GPx]), and neurogenic factor levels (vascular endothelial growth factor [VEGF] and brain-derived neurotrophic factor [BDNF]) in male Wistar rats.

Methods

Rats were assigned to a control (CTL) group, ET group, ET+MitoQ group, and a MitoQ group. Rats were trained on a treadmill for 8 weeks, 5 days/week, and 50 min/day. MitoQ (250 μM daily) was administered through drinking water for 8 weeks. Spatial memory (Morris water maze test), gene expression (real-time PCR), protein expression (Western blotting), and antioxidants (ELISA method) were determined.

Results

Distance and number of passes in the target quarter in the ET, MitoQ, and ET+MitoQ groups were higher than in the CTL group (P=0.001). MitoQ+ET had more impact on the abovementioned indices than MitoQ or ET alone. Simultaneous use of MitoQ and ET significantly increased gene and protein expression of VEGF (P=0.0001) and gene expression of BDNF (P=0.004) and Sestrin 2 (SESN2) (P=0.0001) in hippocampal tissue. The expression of VEGF (P=0.007) and SESN2 (P=0.001) was higher in the MitoQ group compared to the CTL group. Tissue GPx levels were increased following all three interventions (P≤0.013) compared to the CTL group while SOD levels remained unchanged in all groups.

Conclusions

The combination of ET and MitoQ has additive effects on spatial memory in rats by modulating parameters that are involved in hippocampal neurogenesis. In addition, MitoQ may have positive effects on the antioxidant defense by improving GPx activity.

Relevance for Patients

Considering the positive effects of MitoQ on improving the memory and the antioxidant defense, it seems that it can play a positive role in improving the diseases associated with memory loss in the long term, and ET along with this supplement can increase the possible positive effects.

Activity-Dependent Induction of Younger Biological Phenotypes

In several mammalian species, including humans, complex stimulation patterns such as cognitive and physical exercise lead to improvements in organ function, organism health and performance, as well as possibly longer lifespans. A framework is introduced here in which activity-dependent transcriptional programs, induced by these environmental stimuli, move somatic cells such as neurons and muscle cells toward a state that resembles younger cells to allow remodeling and adaptation of the organism. This cellular adaptation program targets several process classes that are heavily implicated in aging, such as mitochondrial metabolism, cell-cell communication, and epigenetic information processing, and leads to functional improvements in these areas. The activity-dependent gene program (ADGP) can be seen as a natural, endogenous cellular reprogramming mechanism that provides deep insight into the principles of inducible improvements in cell and organism function and can guide the development of therapeutic approaches for longevity. Here, these ADGPs are analyzed, exemplary critical molecular nexus points such as cAMP response element-binding protein, myocyte enhancer factor 2, serum response factor, and c-Fos are identified, and it is explored how one may leverage them to prevent, attenuate, and reverse human aging-related decline of body function.

Intense long-term training impairs brain health compared with moderate exercise: Experimental evidence and mechanisms

The consequences of extremely intense long-term exercise for brain health remain unknown. We studied the effects of strenuous exercise on brain structure and function, its dose-response relationship, and mechanisms in a rat model of endurance training. Five-week-old male Wistar rats were assigned to moderate (MOD) or intense (INT) exercise or a sedentary (SED) group for 16 weeks. MOD rats showed the highest motivation and learning capacity in operant conditioning experiments; SED and INT presented similar results. In vivo MRI demonstrated enhanced global and regional connectivity efficiency and clustering as well as a higher cerebral blood flow (CBF) in MOD but not INT rats compared with SED. In the cortex, downregulation of oxidative phosphorylation complex IV and AMPK activation denoted mitochondrial dysfunction in INT rats. An imbalance in cortical antioxidant capacity was found between MOD and INT rats. The MOD group showed the lowest hippocampal brain-derived neurotrophic factor levels. The mRNA and protein levels of inflammatory markers were similar in all groups. In conclusion, strenuous long-term exercise yields a lesser improvement in learning ability than moderate exercise. Blunting of MOD-induced improvements in CBF and connectivity efficiency, accompanied by impaired mitochondrial energetics and, possibly, transient local oxidative stress, may underlie the findings in intensively trained rats.

Cysteine cathepsins: A long and winding road towards clinics

Biomedical research often focuses on properties that differentiate between diseased and healthy tissue; one of the current focuses is elevated expression and altered localisation of proteases. Among these proteases, dysregulation of cysteine cathepsins can frequently be observed in inflammation-associated diseases, which tips the functional balance from normal physiological to pathological manifestations. Their overexpression and secretion regularly exhibit a strong correlation with the development and progression of such diseases, making them attractive pharmacological targets. But beyond their mostly detrimental role in inflammation-associated diseases, cysteine cathepsins are physiologically highly important enzymes involved in various biological processes crucial for maintaining homeostasis and responding to different stimuli. Consequently, several challenges have emerged during the efforts made to translate basic research data into clinical applications. In this review, we present both physiological and pathological roles of cysteine cathepsins and discuss the clinical potential of cysteine cathepsin-targeting strategies for disease management and diagnosis.

Pattern of serum brain-derived neurotrophic factor levels after acute interval exercise versus acute continuous exercise in obese adolescent females

Obesity has been linked to lower cognitive function, while exercise is known to be beneficial in enhancing the cognitive function. Exercise is also known to increase brain-derived neurotrophic factor (BDNF), as the biological marker of cognitive function. This study aimed to analyse the pattern of serum BDNF levels after acute interval exercise (MIE) versus acute continuous exercise (MCE) in obese adolescent females. A total of 24 obese females were enrolled in this study and given acute interval exercise and acute continuous exercise with moderate intensity. The serum level of BDNF in all samples was quantified using ELISA. Statistical analysis was performed using two-way repeated measures ANOVA, and LSD post-hoc test with a 5% significance level. The results revealed pre-exercise mean serum BDNF levels of 254.17±86.90 pg/ml (Control), 263.21±79.82 pg/ml (MIE) and 266.01±33.29 pg/ml (MCE) (P=0.948). The mean serum BDNF levels at 10 min post-exercise were 248.84±44.42 pg/ml (Control), 397.00±31.36 pg/ml (MIE), and 582.82±79.24 pg/ml (MCE) (P=0.000). The mean serum BDNF levels at 6 h post-exercise were 250.05±70.44 pg/ml (Control), 344.50±68.84 pg/ml (MIE), and 364.42±100.87 pg/ml (MCE) (P=0.029). The mean serum BDNF levels at 24 h post-exercise were 244.20±48.55 pg/ml (Control), 252.49±89.11 pg/ml (MIE), and 250.99±65.86 pg/ml (MCE) (P=0.986). It was concluded that serum BDNF in obese adolescent females increased but transiently. Serum BDNF levels increased by acute exercise in both MIE and MCE at 10 min and 6 h post-exercise. However, serum BDNF level at 24 h post-exercise decreased close to the pre-exercise serum BDNF level in all groups. Further research is needed studying the effect of chronic exercise on the kinetics of serum BDNF levels in obese adolescent females.

Antioxidant Molecular Brain Changes Parallel Adaptive Cardiovascular Response to Forced Running in Mice

Physically active lifestyle has huge implications for the health and well-being of people of all ages. However, excessive training can lead to severe cardiovascular events such as heart fibrosis and arrhythmia. In addition, strenuous exercise may impair brain plasticity. Here we investigate the presence of any deleterious effects induced by chronic high-intensity exercise, although not reaching exhaustion. We analyzed cardiovascular, cognitive, and cerebral molecular changes in young adult male mice submitted to treadmill running for eight weeks at moderate or high-intensity regimens compared to sedentary mice. Exercised mice showed decreased weight gain, which was significant for the high-intensity group. Exercised mice showed cardiac hypertrophy but with no signs of hemodynamic overload. No morphological changes in the descending aorta were observed, either. High-intensity training induced a decrease in heart rate and an increase in motor skills. However, it did not impair recognition or spatial memory, and, accordingly, the expression of hippocampal and cerebral cortical neuroplasticity markers was maintained. Interestingly, proteasome enzymatic activity increased in the cerebral cortex of all trained mice, and catalase expression was significantly increased in the high-intensity group; both first-line mechanisms contribute to maintaining redox homeostasis. Therefore, physical exercise at an intensity that induces adaptive cardiovascular changes parallels increases in antioxidant defenses to prevent brain damage.

Physical Activity Levels and Psychological Well-Being during COVID-19 Lockdown among University Students and Employees

During the lockdown for the coronavirus disease 2019 (COVID-19), entire populations were instructed to live in home confinement. We investigated the effects of the COVID-19 lockdown on the physical activity (PA) and mental health of students and employees in a Colombian University. A cross-sectional study was conducted through an online survey during the first isolation. A total of 431 respondents (192 males) aged 18-60 years old (28.1 ± 11.1 years) participated. The international Physical Activity Questionnaire (IPAQ) and the short version of the Psychological General Well-Being Index (PGWBI-S) were used. The lockdown had a negative effect on PA levels, with students exhibiting the greatest decrease (~34%; p ˂ 0.001) compared to employees (~24%; p ˂ 0.01). The analysis showed a greater change in PA behavior before and during the lockdown in highly active student participants (5750 vs. 5141 MET min/week; p < 0.05). Additionally, the psychological assessment revealed a lower score in students compared to employees in the male (70.1 vs. 82.6) and female groups (60.2 vs. 79.6). Moreover, the results revealed an influence of sex, with only the female students exhibiting a state of distress. Self-reported PA and psychological well-being were compromised during the COVID-19 lockdown in the academic community, with students and females being more affected.

Multicomponent exercise program effects on fitness and cognitive function of elderlies with mild cognitive impairment: Involvement of oxidative stress and BDNF

Regular exercise has been shown to be one of the most important lifestyle influences on improving functional performance, and decreasing morbidity and all-cause mortality among older people. However, although there is some evidence on the effects of aerobic training on oxidative stress, there is little information regarding the effects of multicomponent exercise (dual-task training) and combination of exercise with cognitive stimulation on oxidative stress. In this context, the aim of this study was to verify the effects of a multicomponent exercise program on physical fitness and cognitive function in the elderly with mild cognitive impairment and determine the role of oxidative stress and brain-derived neurotrophic factor (BDNF). At baseline, 37 elderly nursing home residents with mild cognitive impairment were divided into two groups: the control group (CG, n = 12, 81.8 years) and the experimental group (EG, n = 25, 83.2 years). These elderlies followed multicomponent exercise training for 24 weeks, with two sessions per week and 45–50 min per session. The exercises included both aerobic and strength exercises, considering functional movements and light to moderate intensity. Cognitive stimulation comprehended exercises based on word games, puzzles, mathematical calculations, forward and backward counting, computer exercises, exergames, and games on a balanced platform. Physical assessments (weight, height, and body mass index), health and functional parameters (fitness tests: chair stand, arm curls, chair sit-and-reach, eight feet up-and-go, back scratch, 6-min walking, feet together, semi-tandem, and full tandem), lipid profile (total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides), measures of lipid peroxidation damage, thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), and BDNF were measured in plasma, based on which analyses were performed before and after the 24 weeks of the multicomponent exercise intervention. The results showed an overall improvement in physical and functional performance. Regarding biochemical measures, multicomponent exercises lead to a significant decrease in oxidative damage. The results indicate that multicomponent exercise training induces benefits in functional capacity and reduces damage due to oxidative stress.

Using a two-sample mendelian randomization analysis to explore the relationship between physical activity and Alzheimer's disease

Evidence from previous epidemiological studies on the effect of physical activity on the risk of Alzheimer's disease (AD) is conflicting. We performed a two-sample Mendelian randomization analysis to verify whether physical activity is causally associated with AD. This study used two-sample Mendelian randomization (MR) analysis to estimate the association between physical activity (including overall activity, sedentary behavior, walking, and moderate-intensity activity) and AD. Genetic instruments for physical activity were obtained from published genome-wide association studies (GWAS) including 91,105 individuals from UK Biobank. Summary-level GWAS data were extracted from the International Genomics of Alzheimer's Project IGAP (21,982 patients with AD and 41,944 controls). Inverse Variance Weighted (IVW) was used to estimate the effect of physical activity on AD. Sensitivity analyses including weighted median, MR-Egger, MR-PRESSO, and leave-one-out analysis were used to estimate pleiotropy and heterogeneity. Mendelian randomization evidences suggested a protective relationship between walking and AD (odds ratio (OR) = 0.30, 95% confidence interval (CI), 0.13-0.68, P = 0.0039). Genetically predicted overall activity, sedentary behavior, and moderate-intensity activity were not associated with AD. In summary, this study provided evidence that genetically predicted walking might associate with a reduced risk of AD. Further research into the causal association between physical activity and AD could help to explore the real relationship and provide more measures to reduce AD risk.

Differences in cognitive function, cardiorespiratory fitness and BDNF concentration in physically active CHD patients vs healthy controls

BACKGROUND

Coronary heart disease (CHD) is frequently associated with cognitive impairment (CI), whereas physical exercise may improve cognition. To date, the cognitive profile of physically active CHD patients remains poorly understood. Physical activity and cognition has been associated with neurotrophic biomarkers that are positively modulated by a higher cardiorespiratory fitness (V̇ O₂peak) and/or active lifestyle. This study aimed to compare the cognitive functions, V̇ O₂peak and trophic biomarkers in physically active CHD patients vs healthy controls.

METHODS

Thirty-nine CHD patients and 20 controls performed a cardiopulmonary exercise test, a neuropsychological assessment (short-term and working memory, processing speed, executive functions, and long-term verbal memory), and a blood draw to measure brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF1), and cathepsin B (CTSB) plasma concentrations. Physical activity was also measured with an accelerometer for 1 week.

RESULTS

Compared to controls, CHD patients had lower V̇ O₂peak (22.2 vs 29.3 mL/min/kg, p<0.001), but similar moderate to vigorous physical activity levels (27.5 vs 34.4 min/day, p=0.114). CHD patients had poorer performances for executive functions (0.198 vs -0.370, p=0.004) and processing speed (0.150 vs -0.293, p=0.025), as well as lower BDNF concentrations (166.4 vs 300.2 ng/ml, p=0.027), but similar IGF-1 and CTSB concentrations (p>0.05) when compared to controls. BDNF was an independent predictor of processing speed in CHD, and IGF-1 and BDNF were independent predictors of verbal memory in healthy controls.

CONCLUSION

Despite similar physical activity levels, fit CHD patients had lower V̇ O₂peak values, cognitive performances (executive functions and processing speed) and BDNF concentrations when compared to controls.

High Intensity Acute Aerobic Exercise Elicits Alterations in Circulating and Skeletal Muscle Tissue Expression of Neuroprotective Exerkines

Background: Cathepsin B (CTSB) and brain derived neurotrophic factor (BDNF) are increased with aerobic exercise (AE) and skeletal muscle has been identified as a potential source of secretion. However, the intensity of AE and the potential for skeletal muscle contributions to circulating CTSB and BDNF have not been fully studied in humans. Objective: Determine the effects of AE intensity on circulating and skeletal muscle CTSB and BDNF expression profiles. Methods: Young healthy subjects (n = 16) completed treadmill-based AE consisting of VO2max and calorie-matched acute AE sessions at 40%, 65% and 80% VO2max. Fasting serum was obtained before and 30-minutes after each bout of exercise. Skeletal muscle biopsies (vastus lateralis) were taken before, 30-minutes and 3-hours after the 80% bout. Circulating CTSB and BDNF were assayed in serum. CTSB protein, BDNF protein and mRNA expression were measured in skeletal muscle tissue. Results: Serum CTSB increased by 20±7% (p = 0.02) and 30±18% (p = 0.04) after 80% and VO2max AE bouts, respectively. Serum BDNF showed a small non-significant increase (6±3%; p = 0.09) after VO2max. In skeletal muscle tissue, proCTSB increased 3 h-post AE (87±26%; p <  0.01) with no change in CTSB gene expression. Mature BDNF protein decreased (31±35%; p = 0.03) while mRNA expression increased (131±41%; p <  0.01) 3 h-post AE. Skeletal muscle fiber typing revealed that type IIa and IIx fibers display greater BDNF expression compared to type I (p = 0.02 and p <  0.01, respectively). Conclusions: High intensity AE elicits greater increases in circulating CTSB compared with lower intensities. Skeletal muscle protein and gene expression corroborate the potential role of skeletal muscle in generating and releasing neuroprotective exerkines into the circulation. NEW AND NOTEWORTHY: 1) CTSB is enriched in the circulation in an aerobic exercise intensity dependent manner. 2) Skeletal muscle tissue expresses both message and protein of CTSB and BDNF. 3) BDNF is highly expressed in glycolytic skeletal muscle fibers.

It's About Time: The Circadian Network as Time-Keeper for Cognitive Functioning, Locomotor Activity and Mental Health

A variety of organisms including mammals have evolved a 24h, self-sustained timekeeping machinery known as the circadian clock (biological clock), which enables to anticipate, respond, and adapt to environmental influences such as the daily light and dark cycles. Proper functioning of the clock plays a pivotal role in the temporal regulation of a wide range of cellular, physiological, and behavioural processes. The disruption of circadian rhythms was found to be associated with the onset and progression of several pathologies including sleep and mental disorders, cancer, and neurodegeneration. Thus, the role of the circadian clock in health and disease, and its clinical applications, have gained increasing attention, but the exact mechanisms underlying temporal regulation require further work and the integration of evidence from different research fields. In this review, we address the current knowledge regarding the functioning of molecular circuits as generators of circadian rhythms and the essential role of circadian synchrony in a healthy organism. In particular, we discuss the role of circadian regulation in the context of behaviour and cognitive functioning, delineating how the loss of this tight interplay is linked to pathological development with a focus on mental disorders and neurodegeneration. We further describe emerging new aspects on the link between the circadian clock and physical exercise-induced cognitive functioning, and its current usage as circadian activator with a positive impact in delaying the progression of certain pathologies including neurodegeneration and brain-related disorders. Finally, we discuss recent epidemiological evidence pointing to an important role of the circadian clock in mental health.

Effects of Leisure-Time Physical Activity on Cognitive Reserve Biomarkers and Leisure Motivation in the Pre-Diabetes Elderly

The purpose of this study was to investigate the change in cognitive reserve biomarkers of the pre-diabetic individual according to the types of leisure-time physical activity (aerobic or resistance physical activity). The research subjects (n = 184) who participated in the survey were pre-diabetic and diabetic patients who were visiting university hospitals and welfare centers. The intervention subjects (n = 36) who were elderly females with pre-diabetes volunteered to participate in the study by performing regular physical exercise (aerobic or resistance exercise). The study participants were 65 years of age or older with pre-diabetes defined by a glycated hemoglobin (HbA1c) level of (5.7−6.4)%. All research subjects performed motivation and stress questionnaire survey. All intervention subjects participated in leisure-time physical activity (LTPA) for 12 weeks. Body composition, HbA1c, and cognitive reserve biomarkers were measured at baseline, and at 6 and 12 weeks. LTPA motivation confirmed that the LTPA participants had a high level of motivation. Stress confirmed that the stress level of LTPA participants was low. Two-way within-factor ANOVA revealed significant group × time interaction for weight (p < 0.05), BMI (p < 0.01), % fat (p < 0.001), SBP (p < 0.05), HbA1c (p < 0.001), BDNF (p < 0.001), and Beta-Amyloid 1−42 (p < 0.001). In both physical activity groups, HbA1c (p < 0.001), NGF (p < 0.05), BDNF (p < 0.05), and Cathepsin B (p < 0.05) improved significantly at 12 weeks, compared to baseline and 6 weeks. In the resistance physical activity group, Beta-Amyloid 1−42 (p < 0.01) and Homocysteine (p < 0.05) significantly decreased at 12 weeks, compared to baseline and at 6 weeks. The LTPA showed high levels of integrated and identified regulation among leisure motive types, and the level of stress was found to be low. The LTPA is effective in reducing the HbA1c levels of the pre-diabetes elderly. In addition, the pre-diabetes elderly were found to have increased NGF, BDNF, and cathepsin B, and decreased Beta-Amyloid 1−42 and homocysteine. Regular leisure-time physical activity has a positive effect on cognitive reserve biomarkers through improving glycemic control by reducing weight and % fat in the pre-diabetes elderly.

Effects of air pollution exposure on inflammatory and endurance performance in recreationally trained cyclists adapted to traffic-related air pollution

The aim of the present study was to analyze the effects of traffic-related air pollution (TRAP) on markers of inflammatory, neuroplasticity, and endurance performance-related parameters in recreationally trained cyclists who were adapted to TRAP during a 50-km cycling time-trial (50-km cycling TT). Ten male cyclists performed a 50-km cycling TT inside an environmental chamber located in downtown Sao Paulo (Brazil), under TRAP or filtered air conditions. Blood samples were obtained before and after the 50-km cycling TT to measure markers of inflammatory [interleukin-6 (IL-6), C-Reactive protein (CRP), interleukin-10 (IL-10), intercellular adhesion molecule-1 (ICAM-1)], and neuroplasticity [brain-derived neurotrophic factor (BDNF)]. Rating of perceived exertion (RPE), heart rate (HR), and power output (PO) were measured throughout the 50-km cycling TT. There were no significant differences between experimental conditions for responses of IL-6, CRP and IL-10 (P > 0.05). When compared with exercise-induced changes in filtered air condition, TRAP provoked greater exercise-induced increase in BDNF levels (TRAP = 3.3 ± 2.4 fold change; Filtered = 1.3 ± 0.5 fold change; P = 0.04) and lower exercise-induced increase in ICAM-1 (Filtered = 1.1 ± 0.1 fold change; TRAP = 1.0 ± 0.1 fold change; P = 0.01). The endurance performance-related parameters (RPE, HR, PO, and time to complete the 50-km cycling TT) were not different between TRAP and filtered air conditions (P > 0.05). These findings suggest that the potential negative impacts of exposure to pollution on inflammatory, neuroplasticity, and performance-related parameters do not occur in recreationally trained cyclists who are adapted to TRAP.

Exercise to spot the differences: a framework for the effect of exercise on hippocampal pattern separation in humans

Exercise has a beneficial effect on mental health and cognitive functioning, but the exact underlying mechanisms remain largely unknown. In this review, we focus on the effect of exercise on hippocampal pattern separation, which is a key component of episodic memory. Research has associated exercise with improvements in pattern separation. We propose an integrated framework mechanistically explaining this relationship. The framework is divided into three pathways, describing the pro-neuroplastic, anti-inflammatory and hormonal effects of exercise. The pathways are heavily intertwined and may result in functional and structural changes in the hippocampus. These changes can ultimately affect pattern separation through direct and indirect connections. The proposed framework might guide future research on the effect of exercise on pattern separation in the hippocampus.

Cathepsin B and Muscular Strength are Independently Associated with Cognitive Control

Although muscular strength has been linked to greater cognitive function across different cognitive domains, the mechanism(s) through which this occurs remain(s) poorly understood. Indeed, while an emerging body of literature suggests peripheral myokines released from muscular contractions may play a role in this relationship, additional research is needed to understand this link. Accordingly, this study sought to compare the influences of a particular myokine, Cathepsin B (CTSB), and muscular strength on hippocampal-dependent relational memory and cognitive control in 40 adults (age = 50.0±7.3 yrs). Overnight fasted venous blood draws were taken to assess plasma CTSB and muscular strength was assessed as maximal isokinetic strength testing using a Biodex dynamometer. Cognitive performance was assessed using a Spatial Reconstruction Task to assess relational memory and a modified Flanker task to assess cognitive control. Neuroelectric function for cognitive control was assessed using event-related potentials (ERPs) recorded during the Flanker task. Initial bivariate correlational analyses revealed that neither sex, age, lean body mass, or muscular strength was associated with CTSB. However, CTSB was inversely associated with reaction time and fractional peak latency of the P3 component of the Flanker task. Muscular strength was also inversely associated with reaction time and positively associated with relational memory performance. However, the influence of muscular strength on relational memory did not persist following adjustment for covariates. Greater circulating CTSB was selectively associated with greater cognitive control as well as faster information processing speed. These findings are the first to link circulating CTSB to both cognitive control and neuroelectric function. Future intervention studies are needed to examine the effects of changes in muscular strength, circulating myokines, and different domains of cognitive function.

Physical activity ameliorates the function of organs via adipose tissue in metabolic diseases

Adipose tissue is a dynamic organ in the endocrine system that can connect organs by secreting molecules and bioactive. Hence, adipose tissue really plays a pivotal role in regulating metabolism, inflammation, energy homeostasis, and thermogenesis. Disruption of hub bioactive molecules secretion such as adipokines leads to dysregulate metabolic communication between adipose tissue and other organs in non-communicable disorders. Moreover, a sedentary lifestyle may be a risk factor for adipose tissue function. Physical inactivity leads to fat tissue accumulation and promotes obesity, Type 2 diabetes, cardiovascular disease, neurodegenerative disease, fatty liver, osteoporosis, and inflammatory bowel disease. On the other hand, physical activity may ameliorate and protect the body against metabolic disorders, triggering thermogenesis, metabolism, mitochondrial biogenesis, β-oxidation, and glucose uptake. Furthermore, physical activity provides an inter-organ association and cross-talk between different tissues by improving adipose tissue function, reprogramming gene expression, modulating molecules and bioactive factors. Also, physical activity decreases chronic inflammation, oxidative stress and improves metabolic features in adipose tissue. The current review focuses on the beneficial effect of physical activity on the cardiovascular, locomotor, digestive, and nervous systems. In addition, we visualize protein-protein interactions networks between hub proteins involved in dysregulating metabolic induced by adipose tissue.