Impact of exercise on markers of B cell-related immunity: A systematic review

BACKGROUND

B cells represent a crucial component of adaptive immunity that ensures long-term protection from infection by generating pathogen-specific immunoglobulins. Exercise alters B cell counts and immunoglobulin levels, but evidence-based conclusions on potential benefits for adaptive immunity are lacking. This systematic review assessed current literatures on the impact of acute exercise and exercise training on B cells, immunoglobulins, and markers of secretory immunity in human biofluids.

METHODS

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, MEDLINE, Web of Science, and Embase were searched on March 8, 2023. Non-randomized controlled trials and crossover trials investigating the impact of acute exercise or exercise training on B cell counts and proportions, immunoglobulin levels, salivary flow rate, or secretory immunoglobulin A secretion rate were included. Quality and reporting of exercise training studies were assessed using the Tool for the Assessment of Study Quality and reporting in Exercise. Study characteristics, outcome measures, and statistically significant changes were summarized tabularly.

RESULTS

Of the 67 eligible studies, 22 applied acute exercise and 45 applied exercise training. All included outcomes revealed significant alterations over time in acute exercise and exercise training context, but only a few investigations showed significant differences compared to control conditions. Secretory and plasma immunoglobulin A levels were most consistently increased in response to exercise training.

CONCLUSION

B cell-related outcomes are altered by acute exercise and exercise training, but evidence-based conclusions cannot be drawn with high confidence due to the large heterogeneity in populations and exercise modalities. Well-designed trials with large sample sizes are needed to clarify how exercise shapes B cell-related immunity.

Effects of inpatient energy management education and high-intensity interval training on health-related quality of life in persons with multiple sclerosis: A randomized controlled superiority trial with six-month follow-up

BACKGROUND

Fatigue is one of the most frequent symptoms in persons with multiple sclerosis (pwMS) and impacts health-related quality of life (HRQoL). A multidisciplinary rehabilitation approach is recommended for the treatment of fatigue in pwMS. However, high-quality evidence exists only for unimodal interventions, such as physical therapies/exercise or energy/fatigue management programmes. The primary objective of the current study was to test the hypothesis that a combination of inpatient energy management education (IEME) and high-intensity interval training (HIIT) is superior to a combination of progressive muscle relaxation (PMR) and moderate continuous training (MCT) for improving HRQoL at 6-month follow-up in fatigued pwMS.

METHODS

A randomized (1:1) controlled superiority trial with fatigued pwMS >18 years of age, with Expanded Disability Status Scale (EDSS) score ≤6.5, recruited at the Valens clinic, Switzerland. Participants in the experimental group performed IEME twice and HIIT 3 times per week and those in the usual care group performed PMR twice and MCT 3 times per week, during a 3-week inpatient rehabilitation stay. Primary outcome was HRQoL (Physical and Mental Component Scales of the Medical Outcome Study 36-item Short Form Health Survey (SF-36)), assessed at entry to the clinic (T0), after 3 weeks' rehabilitation (T1) and 4 (T2) and 6 (T3) months after T0. Secondary outcomes included SF-36 subscales, fatigue (Fatigue Scale for Motor and Cognitive Functions (FSMC)), mood (Hospital Anxiety and Depression Scale (HADS)), self-efficacy for performing energy conservation strategies (Self-Efficacy for Performing Energy Conservation Strategies Assessment (SEPECSA)), self-perceived competence in activities of daily living (Occupational Self Assessment (OSA)) and cardiorespiratory fitness (peak oxygen consumption (VȮ2peak)). Data were analysed using a mixed model for repeated measures approach.

RESULTS

A total of 106 pwMS (age (years): 49.75 (9.87), 66% female, EDSS: 4.64 (1.32)) were recruited. There were no significant group × time interaction effects in the primary and secondary outcomes. There were significant between-group differences in the pairwise comparisons of the group × time interaction in favour of the IEME + HIIT group at: (i) T1 in cardiorespiratory fitness (p = 0.011) and SEPECSA (p = 0.032); (ii) T2 in SF-36 mental health subscale (p = 0.022), HADS anxiety subscale (p = 0.014) and SEPECSA (p = 0.040); (iii) T3 in SF-36 physical functioning subscale (p = 0.012) and SEPECSA (p = 0.003).

CONCLUSION

IEME + HIIT was not superior to PMR + MCT regarding the effects on HRQoL (SF-36 Physical and Mental Component Scales) at 6-month follow-up in pwMS. However, there were significant between-group differences in favour of IEME + HIIT in physical functioning and mental health (SF-36 subscales), anxiety (HADS), cardiorespiratory fitness (VȮ2peak) and self-efficacy (SEPECSA) at different measurement time-points that need to be considered in clinical practice.

Physical activity is related to disease severity and fatigue, but not to relapse rate in persons with relapsing remitting multiple sclerosis - a self-reported questionnaire based study

Introduction

Based on theoretical models, physical activity has been introduced as a promoting method to mitigate the disease severity, fatigue and relapse rate in multiple sclerosis. The primary objective of the study was to investigate the relation between self-reported physical activity level and disease severity, fatigue and relapse rate in persons with relapsing remitting multiple sclerosis (RRMS).

Methods

A survey was offered to persons with RRMS from March 2019 to August 2021 (n = 253). Physical activity level, fatigue and disease severity were determined using the Godin Leisure-Time Questionnaire (GLTEQ), the Patient Determined Disease Steps (PDDS) scale and the Fatigue Scale for Motor and Cognitive Functions (FSMC). Additionally, participants' relapse rate was recorded.

Results

Bivariate correlations revealed an inverse relation between physical activity level and PDDS (ρ = -0.279; p < 0.001) as well as between physical activity and FSMC (r = -0.213, p < 0.001), but not between physical activity and relapse rate (r = 0.033, p > 0.05). Multiple linear regression analyses explained 12.6% and 5.2% of the variance of PDDS and FSMC.

Conclusion

Our findings confirm a relation between self-reported physical activity, disease severity and fatigue in persons with RRMS. However, self-reported physical activity level does not seem to affect the annualised relapse rate.

12-week combined strength and endurance exercise attenuates CD8+ T-cell differentiation and affects the kynurenine pathway in the elderly: a randomized controlled trial

BACKGROUND

Age-related accumulation of highly differentiated CD8⁺ effector memory re-expressing CD45RA (EMRA) T-cells and disruption of the kynurenine (KYN) pathway are associated with chronic inflammation and the development of insulin resistance. In this study the aim was to investigate the effects of 12-week combined strength and endurance exercise on CD8⁺ T-cell differentiation and KYN pathway metabolites. Ninety-six elderly subjects (f/m, aged 50-70) were randomized to a control (CON) or exercise (EX) group. The EX group completed combined strength and endurance training twice weekly for one hour each time at an intensity of 60% of the one-repetition maximum for strength exercises and a perceived exertion of 15/20 for endurance exercises. The EX group was also randomly subdivided into two groups with or without a concomitant balanced diet intervention in order to examine additional effects besides exercise alone. Before and after the intervention phase, the proportions of CD8⁺ T-cell subsets and levels of KYN pathway metabolites in peripheral blood were determined.

RESULTS

The CD8⁺ EMRA T-cell subsets increased in the CON group but remained almost unchanged in the EX group (p = .02). Plasma levels of kynurenic acid (KA) increased in the EX group and decreased in the CON group (p = .03). Concomitant nutritional intervention resulted in lower levels of quinolinic acid (QA) compared with exercise alone (p = .03). Overall, there was a slight increase in the QA/KA ratio in the CON group, whereas it decreased in the EX group (p > .05).

CONCLUSIONS

Combined strength and endurance training seems to be a suitable approach to attenuate CD8⁺ T-cell differentiation in the elderly and to redirect the KYN pathway towards KA. The clinical relevance of these effects needs further investigation.

Cycling in primary progressive multiple sclerosis (CYPRO): study protocol for a randomized controlled superiority trial evaluating the effects of high-intensity interval training in persons with primary progressive multiple sclerosis

BACKGROUND

Primary progressive multiple sclerosis (PPMS) is the least prevalent multiple sclerosis (MS) phenotype. For persons with PPMS (pwPPMS), pharmacological treatment options are limited. As a complementary non-pharmacological treatment, endurance training improves the health-related quality of life (HRQoL), numerous MS symptoms, and MS-related performance impediments. High-intensity interval training (HIIT) has been shown to induce superior effects compared to moderate-intensity continuous training (MCT). As current evidence is based on MS samples with mixed phenotypes, generalizability to pwPPMS remains unclear.

METHODS

CYPRO is a parallel-group, single-center, and single-blind randomized controlled superiority trial evaluating the effects of HIIT compared to MCT in pwPPMS. Sixty-one pwPPMS are randomized (1:1) to perform volume-matched HIIT or MCT sessions on bicycle ergometers two to three times per week in addition to standard rehabilitative care during their three-week inpatient stay at Valens rehabilitation clinic, Switzerland. Standard rehabilitative care comprises endurance and strength training, physiotherapy, and occupational therapy. HIIT sessions include six 90-second intervals at 95% peak heart rate (HR_peak), interspersed by 90-second active breaks with unloaded pedaling, aimed to reach 60%HR_peak. MCT represents the standard treatment at Valens rehabilitation clinic and is performed as continuous cycling at 60%HR_peak for the duration of 26 minutes. The primary outcome is cardiorespiratory fitness, assessed as peak oxygen consumption (V̇O_2peak) during cardiopulmonary exercise testing (CPET). Secondary outcomes include peak power output during CPET, walking capacity, cognitive performance, HRQoL, fatigue, anxiety and depressive symptoms, and blood-derived biomarkers (e.g., serum neurofilament light chain, glial fibrillary acidic protein, kynurenine pathway metabolites) related to MS pathophysiology. All outcomes are assessed at baseline and discharge after three weeks. Venous blood sampling is additionally performed immediately and two hours after the first HIIT or MCT session.

DISCUSSION

CYPRO will expand current knowledge on symptom management and rehabilitation in MS to the subpopulation of pwPPMS, and will contribute to the exploration of potential disease-modifying effects of endurance training in MS. The superiority design of CYPRO will allow deriving explicit recommendations on endurance training design in pwPPMS that can be readily translated into clinical practice.

TRIAL REGISTRATION

CYPRO has been prospectively registered at ClinicalTrials.gov on 8 February 2022 (NCT05229861).

Tissue-specific effects of exercise as NAD+ -boosting strategy: Current knowledge and future perspectives

Nicotinamide adenine dinucleotide (NAD⁺ ) is an evolutionarily highly conserved coenzyme with multi-faceted cell functions, including energy metabolism, molecular signaling processes, epigenetic regulation, and DNA repair. Since the discovery that lower NAD⁺ levels are a shared characteristic of various diseases and aging per se, several NAD⁺ -boosting strategies have emerged. Other than pharmacological and nutritional approaches, exercise is thought to restore NAD⁺ homeostasis through metabolic adaption to chronically recurring states of increased energy demand. In this review we discuss the impact of acute exercise and exercise training on tissue-specific NAD⁺ metabolism of rodents and humans to highlight the potential value as NAD⁺ -boosting strategy. By interconnecting results from different investigations, we aim to draw attention to tissue-specific alterations in NAD⁺ metabolism and the associated implications for whole-body NAD⁺ homeostasis. Acute exercise led to profound alterations of intracellular NAD⁺ metabolism in various investigations, with the magnitude and direction of changes being strongly dependent on the applied exercise modality, cell type, and investigated animal model or human population. Exercise training elevated NAD⁺ levels and NAD⁺ metabolism enzymes in various tissues. Based on these results, we discuss molecular mechanisms that might connect acute exercise-induced disruptions of NAD⁺ /NADH homeostasis to chronic exercise adaptions in NAD⁺ metabolism. Taking this hypothesis-driven approach, we hope to inspire future research on the molecular mechanisms of exercise as NAD⁺ -modifying lifestyle intervention, thereby elucidating the potential therapeutic value in NAD⁺ -related pathologies.

The serum kynurenine pathway metabolic profile is associated with overweight and obesity in multiple sclerosis

BACKGROUND

Overweight and obesity increase multiple sclerosis (MS) susceptibility, disease severity, and disability progression. Kynurenine pathway (KP) dysregulation is present in overweight and obesity, and in MS. Since the effect of overweight and obesity on KP dysregulation in persons with MS (pwMS) remains to be established, this study primarily aims to explore the effect of overweight and obesity on the serum KP metabolic profile in pwMS.

METHODS

This cross-sectional study represents a secondary analysis of a randomized clinical trial at Valens rehabilitation clinic, Switzerland. Registration was performed on 22 April 2020 at clinicaltrials.gov (NCT04356248, https://clinicaltrials.gov/ct2/show/NCT04356248). The first participant was enrolled on 13 July 2020. Based on body mass index (BMI), 106 MS inpatients (Expanded Disability Status Scale (EDSS) score ≤ 6.5) were dichotomised to a lean group (LG, BMI < 25 kg/m²), and an overweight/obese group (OG, BMI ≥ 25 kg/m²). Targeted metabolomics (LC-MS/MS) was performed to determine serum concentrations of tryptophan (TRP), KP downstream metabolites, and neopterin (Neopt). Correlations between BMI, kynurenine-to-TRP ratio (KTR), and serum concentrations of TRP, KP downstream metabolites, and Neopt were calculated. ANCOVA was used to determine differences in KTR, and serum concentrations of TRP, KP downstream metabolites and Neopt between OG and LG, and across MS phenotypes.

RESULTS

Higher BMI correlated with higher KTR (r = 0.425, p <0.001) and serum concentrations of most KP downstream metabolites, but not with EDSS score. Higher KTR (r = 0.470, p < .001) and serum concentrations of most KP downstream metabolites correlated with a higher serum concentration of Neopt. The OG (n = 44, 59% female, 51.68 (9.98) years, EDSS: 4.71 (1.37)) revealed higher KTR (0.026 (0.007) vs. 0.022 (0.006), p=.001) and serum concentrations of most KP downstream metabolites than the LG (n = 62, 71% female, 48.37 (9.63) years, EDSS: 4.60 (1.29)). KP metabolic profiles did not differ between MS phenotypes.

CONCLUSION

Overweight and obesity are associated with a systemic elevation of KP metabolic flux and an accumulation of most KP downstream metabolites in pwMS. Further research is needed to clarify if KP involvement serves as a mechanism linking overweight and obesity with symptom expression, disease severity, and disability progression in pwMS.

Cellular Integrative Immune Markers in Elite Athletes

The integrative immune markers neutrophil-lymphocyte-ratio (NLR), platelet-lymphocyte-ratio (PLR) and systemic immune inflammation index (SII) are established markers in clinical patient care. Adoption of these markers in elite athletics might prove beneficial for monitoring training and health. Blood samples of 195 healthy national Olympic squad athletes were collected before a graded bicycle-ergometric exercise test until complete exhaustion. Measurements included white blood cells, lymphocytes and platelets, allowing for the calculation of the integrative immune markers. Correlations between athlete characteristics (sex, age, sporting discipline, training experience, training volume) and integrative immune marker-values were assessed. In a subgroup analysis a second blood sample was collected from 25 athletes at 1 minute after exercise test to assess its effect on the immune marker levels.An inverse correlation between peak power output and SII-level (Pearson correlation coefficient=-.270, p<.001) and NLR-level (Pearson correlation coefficient=-.249, p<.001) was found. Athletes with higher aerobic fitness had significantly lower values of SII and PLR compared to athletes with lower aerobic fitness. An elevated SII (p=.003) and a reduced PLR (p=.001) was documented as acute response to the exercise test. The integrative immune markers might be a promising tool for monitoring training and health in elite athletes.

Effect of sleep and fatigue on cardiovascular performance in young, healthy subjects

Physical performance could be negatively affected by sleep deficiency and fatigue. The present study assesses the role of sleep quality, fatigue and motivation on cardiovascular performance (VO₂peak, Wmax, and HRmax) in a sample of active young subjects. The current study is a cross-sectional design. Ninety-six university students (males 54.2%; 21.5 ± 2.9 yrs) completed an incremental exercise test on a bicycle ergometer. Sleep, fatigue, and motivation were assessed with the Pittsburgh Sleep Quality Index and two visual analogue scales, respectively. Differences in VO₂peak, Wmax, HRmax, self-perceived fatigue and motivation were compared between good and bad sleepers and sleep duration >/<7.5 h, while regression analysis defined the predictors of VO₂peak, Wmax, and HRmax_. In the male sample, good and bad sleepers' differences were significant only for self-perceived fatigue (p = 0.04). The female sample showed no statistically significant differences between good and bad sleepers and different sleep durations. In the male sample, linear regression analysis showed a significant inverse correlation between Wmax and the PSQI score (-0.4, p = 0.004). The stepwise regression model indicated that sleep (β = -0.3, p = 0.02) was a significant predictor of VO₂peak in males accounting for 20% of the variance, whereas physical performance seems more affected by fatigue (β = -0.4, p = 0.03) in females. In conclusion, chronic inadequate and self-reported sleep quality seems to be one of the factors compromising cardiovascular performance in males.

Distinct distribution patterns of exercise-induced natural killer cell mobilisation into the circulation and tumor tissue of patients with prostate cancer

The mobilization and activation of natural killer (NK) cells have been proposed as key mechanisms promoting anti oncogenic effects of physical exercise. Although mouse models have proven that physical exercise recruits NK cells to tumor tissue and inhibits tumor growth, this preclinical finding has not been transferred to the clinical setting yet. In this first-in-human study, we found that physical exercise mobilizes and redistributes NK cells, especially those with a cytotoxic phenotype, in line with preclinical models. However, physical exercise did not increase NK cell tumor infiltrates. Future studies should carefully distinguish between acute and chronic exercise modalities and should be encouraged to investigate more immune responsive tumor entities.

Is high-intensity interval training harmful to health?

High-intensity interval training (HIIT) is a common method to increase performance and promote health in elite sports, rehabilitation, and disease prevention. Flockhart et al. suggest a limit of HIIT above which detrimental effects on metabolic health emerge. We put these findings into context and assess the evidence that HIIT might be harmful.

Exercise reduces systemic immune inflammation index (SII) in childhood cancer patients

While exercise and physical activity have been suggested to reduce mortality and symptoms in cancer, knowledge on these associations in patients with childhood cancer (CCPs) is sparse. Anti-inflammatory properties of exercise might mediate these beneficial effects. We investigated the influence of exercise on the inflammation markers neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and systemic-immune-inflammation index (SII) and associations to patient-reported-outcomes in CCPs in a randomized-controlled trial. Results show associations between inflammation markers and patient-reported outcomes. Compared to the control group, SII was significantly reduced following exercise (p=0.036). Anti-inflammatory effects of exercise are also present in CCPs and may underlie exercise-induced benefits on symptoms. Clinical Trial Registration Number: NCT02612025

Systematic Review of Exercise Studies in Persons with Multiple Sclerosis: Exploring the Quality of Interventions According to the Principles of Exercise Training

INTRODUCTION

The objective of this systematic review is to explore the application and reporting of (i) the principles of exercise training in exercise trials, (ii) the components of exercise prescription, and (iii) the adherence towards the prescribed programmes in randomised controlled trials (RCTs) in persons with multiple sclerosis (pwMS).

METHODS

The MEDLINE, CINAHL, SPORTDiscus, PubMed and Embase electronic databases were searched from 1 January 2000 to 16 October 2020. RCTs comprising at least 3 weeks of aerobic and/or resistance exercise intervention in pwMS that reported at least one physiological outcome and were published in peer-reviewed journals were eligible for inclusion.

RESULTS

Out of 52 RCTs included in this review, 58 intervention arms were examined. None applied more than four principles of exercise training. Specificity was addressed by 85%, progression by 33%, overload by 59%, initial values by 26%, reversibility by 0% and diminishing returns by 2% of trials. Fifty-two percent of trials reported all components of exercise prescription, and 3% of trials reported the level of adherence to the prescribed exercise.

CONCLUSION

This systematic review reveals that exercise training principles were not respected in the majority of included RCTs. The weak quality of reported exercise interventions limits the interpretation of the studies' results and potentially leads to an underestimation of 'exercise as medicine' in pwMS. Also, the vague descriptions of exercise prescription and adherence impede the reproducibility of results. Future studies must attend to all principles of exercise training and provide transparent information on the prescribed and performed programmes to develop specific and valid exercise recommendations for pwMS.

SYSTEMATIC REVIEW REGISTRATION

CRD42020162671, 28/04/2020, PROSPERO.

How acute physical and psychological stress differentially influence the kynurenine pathway: A randomized cross-over trial

Psychological stress is associated with the pathogenesis of several neuropsychiatric disorders. In contrast, physical stress, as provoked by exercise, counteracts symptoms and potentially also disease progression. The kynurenine pathway, which is imbalanced in neuropsychiatric disorders, responds to both psychological and physical stress. Here, we compared the acute effects of psychological versus physical stress on the kynurenine pathway and inflammatory mediators. Thirty-five healthy males (mean age: 24.09±3.39 years) underwent both the Trier Social Stress Test (psychological stressor) and the Wingate-Test (physical stressor). The kinetics of tryptophan and its metabolites as well as cytokines IL-6, IFN-γ, TNF-α, and IL-10 were measured before and after the two stress conditions. After both stressors, there was a significant change over time for the kinetics of tryptophan metabolites and for cytokines. Furthermore, the reactivity of kynurenine pathway metabolite ratios and cytokines was statistically greater after physical stress than after psychological stress. The increased metabolic flux towards kynurenic acid following acute physical stress suggests an exercise-induced neuroprotective mechanism. Despite the paradoxical influence of both stressors on neuropsychiatric diseases, the acute kynurenine pathway reactivity appears to be similar, although effects were more pronounced in response to physical stress.

The kynurenine pathway in chronic diseases: a compensatory mechanism or a driving force?

The kynurenine (KYN) pathway (KP) of tryptophan (TRP) metabolism is dysregulated in inflammation-driven pathologies including oncological and brain diseases [e.g., multiple sclerosis (MS), depression] and thus is a promising therapeutic target. Both pathological and compensatory mechanisms underlie disease-associated KP activation. There is growing evidence for bioenergetic roles of certain KP metabolites such as kynurenic acid (KA), or quinolinic acid (QA) as an NAD⁺ precursor, which may explain its frequently observed 'pathological' overactivation. Disease- and tissue-specific aspects, negative feedback on inflammatory signals, and the balance of downstream metabolites are likely to be decisive factors in the interpretation of an imbalanced KP. Therapeutic strategies should consider the compensatory actions and bioenergetic roles of KP metabolites to successfully design future theragnostic approaches aimed at attenuating disease progression.

VO2peak Response Heterogeneity in Persons with Multiple Sclerosis: To HIIT or Not to HIIT?

Exercise is described to provoke enhancements of cardiorespiratory fitness in persons with Multiple Sclerosis (pwMS). However, a high inter-individual variability in training responses has been observed. This analysis investigates response heterogeneity in cardiorespiratory fitness following high intensity interval (HIIT) and moderate continuous training (MCT) and analyzes potential predictors of cardiorespiratory training effects in pwMS. 131 pwMS performed HIIT or MCT 3-5x/ week on a cycle ergometer for three weeks. Individual responses were classified. Finally, a multiple linear regression was conducted to examine potential associations between changes of absolute peak oxygen consumption (absolute ∆V̇O_2peak/kg)_, training modality and participant's characteristics. Results show a time and interaction effect for ∆V̇O_2peak/kg. Absolute changes of cardiorespiratory responses were larger and the non-response proportions smaller in HIIT vs. MCT. The model accounting for 8.6% of the variance of ∆V̇O_2peak/kg suggests that HIIT, younger age and lower baseline fitness predict a higher absolute ∆V̇O_2peak/kg following an exercise intervention. Thus, this work implements a novel approach that investigates potential determinants of cardiorespiratory response heterogeneity within a clinical setting and analyzes a remarkable bigger sample. Further predictors need to be identified to increase the knowledge about response heterogeneity, thereby supporting the development of individualized training recommendations for pwMS.

Transferring clinically established immune inflammation markers into exercise physiology: focus on neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and systemic immune-inflammation index

Over the last decades the cellular immune inflammation markers neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII = NLR × platelets) have emerged in clinical context as markers of disease-related inflammation and are now widely appreciated due to their integrative character. Transferring these clinically established inflammation markers into exercise physiology seems highly beneficial, especially due to the low temporal, financial and infrastructural resources needed for assessment and calculation. Therefore, the aim of this review is to summarize evidence on the value of the integrative inflammation markers NLR, PLR and SII for depiction of exercise-induced inflammation and highlight potential applications in exercise settings. Despite sparse evidence, multiple investigations revealed responsiveness of the markers to acute and chronic exercise, thereby opening promising avenues in the field of exercise physiology. In performance settings, they might help to infer information for exercise programming by reflecting exercise strain and recovery status or periods of overtraining and increased infection risk. In health settings, application involves the depiction of anti-inflammatory effects of chronic exercise in patients exhibiting chronic inflammation. Further research should, therefore, focus on establishing reference values for these integrative markers in athletes at rest, assess the kinetics and reliability in response to different exercise modalities and implement the markers into clinical exercise trials to depict anti-inflammatory effects of chronic exercise in different patient collectives.

Abdominal Obesity-Related Disturbance of Insulin Sensitivity Is Associated with CD8+ EMRA Cells in the Elderly

Aging and overweight increase the risk of developing type 2 diabetes mellitus. In this cross-sectional study, we aimed to investigate the potential mediating role of T-EMRA cells and inflammatory markers in the development of a decreased insulin sensitivity. A total of 134 healthy older volunteers were recruited (age 59.2 (_SD 5.6) years). T cell subpopulations were analyzed by flow cytometry. Furthermore, body composition, HOMA-IR, plasma tryptophan (Trp) metabolites, as well as cytokines and adipokines were determined. Using subgroup and covariance analyses, the influence of BMI on the parameters was evaluated. Moreover, correlation, multiple regression, and mediation analyses were performed. In the subgroup of participants with obesity, an increased proportion of CD8+EMRA cells and elevated concentrations of plasma kynurenine (KYN) were found compared to the lower-weight subgroups. Linear regression analysis revealed that an elevated HOMA-IR could be predicted by a higher proportion of CD8+EMRA cells and KYN levels. A mediation analysis showed a robust indirect effect of the Waist-to-hip ratio on HOMA-IR mediated by CD8+EMRA cells. Thus, the deleterious effects of abdominal obesity on glucose metabolism might be mediated by CD8+EMRA cells in the elderly. Longitudinal studies should validate this assumption and analyze the suitability of CD8+EMRA cells as early predictors of incipient prediabetes.

Exercise Diminishes Plasma Neurofilament Light Chain and Reroutes the Kynurenine Pathway in Multiple Sclerosis

OBJECTIVE

To examine acute (single-bout) and training effects of high-intensity interval training (HIIT) vs standard exercise therapy (moderate continuous training [MCT]) on plasma neurofilament light chain (pNfL) and kynurenine (KYN) pathway of tryptophan degradation metabolites in persons with multiple sclerosis (pwMS).

METHODS

Sixty-nine pwMS (Expanded Disability Status Scale score 3.0-6.0) were randomly assigned to a HIIT or an MCT group. Changes in pNfL and KYN pathway metabolites measured in blood plasma were assessed before, after, and 3 hours after the first training session as well as after the 3-week training intervention.

RESULTS

Acute exercise reduced pNfL and increased the KYN pathway flux toward the neuroprotective kynurenic acid (KA). Changes in pNfL correlated positively with changes in KA and negatively with the quinolinic acid-to-KA ratio. HIIT consistently led to greater effects than MCT. Following the 3-week training intervention, the KYN pathway was activated in HIIT compared with MCT.

CONCLUSION

Future studies and clinical assessments of pNfL should consider acute exercise as confounding factor for measurement reliability. Moreover, exercise-induced KYN pathway rerouting might mediate neuroprotection, potentially underlying the benefits in rehabilitation for pwMS.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that acute HIIT diminishes pNfL and increases KA levels, and 3 weeks of HIIT activate the KYN pathway in pwMS.

TRIAL REGISTRATION INFORMATION

Clinical trial registration number: NCT03652519.

Do baseline cognitive status, participant specific characteristics and EDSS impact changes of cognitive performance following aerobic exercise intervention in multiple sclerosis?

PURPOSE

Cognitive impairment is a common symptom of multiple sclerosis (MS). Physical exercise represents a promising non-pharmacological therapy option, however, potential predictors for successful cognitive improvements mediated by exercise remain to be elucidated in order to optimize targeted exercise training regimens. One of the most promising exercise training regime in this context is high-intensity interval training (HIIT). Against this backdrop, this study i) analysed the effects of a three-week HIIT compared to moderate continuous exercise on cognitive performance and ii) investigated potential predictors for changes of cognitive performance following a three-week aerobic exercise intervention.

METHODS

Datasets of two randomized controlled trials (RCT) were pooled, resulting in a total sample size of n = 130 persons with MS (pwMS) who either performed HIIT or moderate intensity continuous (MCT) exercise 3-5x/ week for three weeks. Cognitive performance was assessed with the Brief International Cognitive Assessment for MS. I) Potential within (time) and interaction (time x group) effects for cognitive performance were investigated with univariate analyses of covariance (ANCOVA). II) Potential predictors for changes of cognitive performance were assessed by multiple linear regression models.

RESULTS

ANCOVA revealed significant time effects for all cognitive outcomes and a time x group interaction for verbal learning (p=.045), with HIIT inducing superior effects compared to moderate continuous exercise (MCT). Cognitive status (impaired/intact cognition) (p= .008) and exercise regime (HIIT/moderate continuous) (p=.040) influenced changes of verbal learning. Cognitive status (p=.006) and EDSS (p=.048) affected changes of visuospatial memory in pwMS. The models accounted for 5.4% and 7.7% of the variance.

CONCLUSION

Cognitive status, exercise regime and EDSS potentially impact changes of specific cognitive domains following aerobic exercise. Further predictors for changes of cognitive performance following an aerobic exercise intervention need to be investigated as current results accounted only for a limited amount of variance. RCTs that investigate effects of physical exercise on cognitive performance should include only pwMS with impaired baseline cognitive performance. To better understand the impact of exercise on cognitive performance, it is furthermore recommendable to include cognitive assessments in clinical routine.

High-intensity interval training and energy management education, compared with moderate continuous training and progressive muscle relaxation, for improving health-related quality of life in persons with multiple sclerosis: study protocol of a randomized controlled superiority trial with six months' follow-up

Background

Persons with multiple sclerosis (PwMS) often have reduced aerobic capacity and report fatigue as the most disabling symptom impacting their health-related quality of life (HRQoL). A multidisciplinary rehabilitation approach is recommended for successful management of symptoms, although there is little supporting evidence. The aim of this study is to evaluate the effect of a multimodal therapy approach, including endurance training and patient education, during a three-week inpatient rehabilitation stay, on HRQoL in PwMS at six months follow-up. Inpatient energy management education (IEME) + high-intensity interval training (HIIT) will be compared with progressive muscle relaxation (PMR) + moderate continuous training (MCT).

Methods

This study has a two-armed single-blind randomized controlled superiority trial design. One hundred six PwMS-related fatigue (relapsing-remitting or chronic progressive phenotypes; Expanded Disability Status Scale (EDSS) ≤ 6.5) will be recruited at the Valens clinic, Switzerland, and randomized into either an experimental (EG) or a control group (CG). EG: participants will perform IEME twice and HIIT three times per week during the three-week rehabilitation stay. IEME is a group-based intervention, lasting for 6.5 h over three weeks. HIIT contains of five 1.5-min high-intensive exercise bouts on a cycle ergometer at 95–100% of peak heart rate (HR_peak), followed by active breaks of unloaded pedalling for 2 min to achieve 60% of HR_peak. CG: participants will perform PMR twice and MCT three times per week during the three-week rehabilitation stay, representing local usual care. PMR consists of six 1-h relaxation group sessions. MCT consists of 24-min continuous cycling at 65% of HR_peak. The primary outcome is HRQoL (Physical and Mental Component Summaries of the Medical Outcome Study 36-item Short Form Health Survey; SF-36), measured at entry to the clinic (baseline, T₀), three weeks after T₀ (T₁) and at four (T₂) and six (T₃) months after T₀. Secondary outcomes comprise cardiorespiratory fitness, inflammatory markers (measured at T₀ and T₁), fatigue, mood, self-efficacy, occupational performance, physical activity (measured at T₀, T₁, T₂ and T₃) and behaviour changes in energy management (measured at T₂ and T₃).

Discussion

This study will provide detailed information on a multimodal therapy approach to further improve rehabilitation for PwMS.

Trial registration

This trial was prospectively registered at ClinicalTrials.gov (NCT04356248; 22 April 2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02084-0.

Feasibility and suitability of a graded exercise test in patients with aggressive hemato-oncological disease

Purpose

Physical activity promises to reduce disease-related symptoms and therapy-related side effects in patients suffering from aggressive lymphoma (L) or acute leukemia (AL). For an efficient training program, determination of patients’ physical capacity with a purposive exercise test is crucial. Here, we evaluated the feasibility and suitability of a graded exercise test (GXT) frequently applied in patients suffering from solid tumors by assessing whether patients achieved criteria for maximal exercise testing according to the American College of Sports Medicine (ACSM).

Methods

The GXT was performed by 51 patients with an aggressive L or AL prior to the start or in the earliest possible phase of high-dose chemotherapy, following a recommended protocol for cancer patients, starting at 20 Watts (W), with an increase of 10 W/min until volitional exhaustion. Subsequently, we investigated whether the following ACSM criteria were fulfilled: (1) failure of heart rate to increase despite increasing workload, (2) post-exercise capillary lactate concentration ≥ 8.0 mmol L⁻¹, (3) rating of perceived exertion at exercise cessation > 17 on the 6–20 Borg Scale.

Results

Out of 51 patients, two, six, and 35 participants met the first, second, and third criterion, respectively. No relevant relationships between the completion of the criteria and patients’ characteristics (e.g., gender, age) were found.

Conclusion

Although results of this study suggest a general feasibility of the applied GXT, the ACSM criteria were not met by the majority of the participants. Therefore, this study raises doubts about the suitability of the GXT protocol and the ACSM criteria for this group of patients.

Cognitive Impairment Impacts Exercise Effects on Cognition in Multiple Sclerosis

Purpose: Exercise training reveals high potential to beneficially impact cognitive performance in persons with multiple sclerosis (pwMS). Research indicates that high-intensity interval training (HIIT) has potentially higher effects on physical fitness and cognition compared to moderate continuous exercise. This study (i) compares the effects of a 3-week HIIT and moderate continuous exercise training on cognitive performance and cardiorespiratory fitness of pwMS in an overall analysis and (ii) investigates potential effects based on baseline cognitive status in a subgroup analysis. Methods: Seventy-five pwMS were randomly assigned to an intervention (HIIT: 5 × 1.5-min intervals at 95-100% HR_max, 3 ×/week) or active control group (CG: 24 min continuous exercise at 65% HR_max, 3 ×/week). Cognitive performance was assessed pre- and post-intervention with the Brief International Cognitive Assessment for MS (BICAMS). (I) To examine potential within (time) and interaction (time × group) effects in the overall analysis, separate analyses of covariance (ANCOVA) were conducted. (II) For the subgroup analysis, participants were divided into two groups [intact cognition or impaired cognition (>1.5 standard deviation (SD) compared to healthy, age-matched norm data in at least one of the three tests of the BICAMS]. Potential impacts of cognitive status and intervention were investigated with multivariate analyses of variance (MANOVA). Results: Overall analysis revealed significant time effects for processing speed, verbal learning, rel. VO2peak, and rel. power output. A time^*group interaction effect was observed for rel. power output. Subgroup analysis indicated a significant main effect for cognition (impaired cognition vs. intact cognition). Subsequent post-hoc analysis showed significant larger effects on verbal learning in pwMS with impaired cognition. Conclusion: Current results need to be confirmed in a powered randomized controlled trial with cognitive performance as primary endpoint and eligibility based on cognitive performance that is assessed prior to study inclusion.

The effect of exercise on regulatory T cells: A systematic review of human and animal studies with future perspectives and methodological recommendations

Many of the exercise-related health-promoting effects are attributed to beneficial immunomodulation. The restoration of immune homeostasis is context-dependent, meaning either to increase anti-inflammatory signaling to counteract disease progression of non-communicable (auto)inflammatory diseases or to enhance (local) activity of proinflammatory immune cells to slow down or inhibit cancer progression. Regulatory CD4+ T cells (Tregs) represent the main regulatory component of the adaptive immune system that fine-tunes inflammatory responses, keeps them in check and prevents long-lasting autoimmunity. Because often dysregulated in the context of various diseases, emerging treatment approaches aim to modulate their number or inherent anti-inflammatory and immunosuppressive function in a highly disease-specific way. Exercise represents a non-pharmacologic strategy in disease prevention and rehabilitation and may be an effective treatment with few to no side effects to counteract dysregulation of Tregs. To date, several studies have evaluated the effect of exercise on Treg-related outcomes. This review aims at providing a comprehensive overview on alterations of blood- or tissue-derived Treg counts, proportion and functionality following acute and chronic exercise in humans and animal models. From the 60 reviewed studies, an overall disease-specific beneficial effect of chronic exercise on Treg levels in animal models can be stated, while both acute and chronic effects in human studies are less definite. However, Treg phenotyping is less sufficient in the animal studies compared to human studies. Only a limited number of studies investigated Treg functionality. There is a large heterogeneity concerning study design, human population or animal model, exercise protocol, and Treg outcome measure specification which makes it difficult to compare results and draw clear conclusions. Study results are discussed in the context of current concepts in exercise immunology. Finally, future perspectives and methodological recommendations are provided to promote research in this field.

Acute exercise impacts AhR and PD-1 levels of CD8+ T-cells-Exploratory results from a randomized cross-over trial comparing endurance versus resistance exercise

Purpose

The programmed cell death protein 1 (PD-1) has become a promising target in cancer immunotherapy. PD-1 expression of CD8⁺ T-cells may be increased via the exploitation of aryl hydrocarbon receptor (AhR) signaling with kynurenine (KYN) as a ligand. Since exercise affects KYN metabolism, we exploratory investigated the influence of acute exercise bouts on AhR and PD-1 levels of CD8⁺ T-cells.

Method

In this study, 24 healthy males (age: 24.6 ± 3.9 years; weight 83.9 ± 10.5 kg; height: 182.4 ± 6.2 cm) completed a single bout of endurance (EE) and resistance exercise (RE) in a randomly assigned order on separate days. Blood samples were drawn before (t0), after (t1), and 1 h after (t2) both conditions. T-cell populations, the level of cytoplasmic AhR, and surface PD-1 were assessed by flow cytometry.

Results

T-cell populations changed over time, indicated by an increase in the absolute numbers of CD3⁺ lymphocytes after EE (p < .001) and RE (p = .036) and in PD-1⁺ CD8⁺ T-cells after EE (p = .021). Proportions of T-cell populations changed only after EE (t0–t2: p = .029; t1-t2: p = .006). The level of cytoplasmic AhR decreased immediately after exercise in both exercise conditions (EE: p = .009; RE: p = .036). The level of surface PD-1 decreased 1 h after EE (p = .005).

Conclusion

We analyzed the level of surface PD-1 and cytoplasmic AhR following acute physical exercise for the first time. Especially EE was observed to impact both AhR and PD-1 levels, undermining its role as the AhR-PD-1 axis modulator. These results provide new insights into the impact of exercise on AhR-signaling, which could potentially be relevant for various chronic diseases.

Electronic supplementary material

The online version of this article (10.1007/s00421-020-04552-w) contains supplementary material, which is available to authorized users.

High-intensity interval training reduces neutrophil-to-lymphocyte ratio in persons with multiple sclerosis during inpatient rehabilitation

In persons with multiple sclerosis (PwMS), the neutrophil-to-lymphocyte ratio (NLR) is associated with disability status, symptomatology and disease activity. High-intensity interval training (HIIT) improves many symptoms in PwMS and may positively influence disease progression. Here, we present results from a randomized controlled trial during inpatient rehabilitation on immediate (single bout) and training (3-week intervention) effects of HIIT versus moderate continuous training on NLR and related cellular inflammation markers. Only HIIT reduced the NLR over the 3-week intervention period. These training effects might be due to repetitive inflammatory states with compensatory anti-inflammatory counterbalancing after each HIIT session.

Physical Exercise as Kynurenine Pathway Modulator in Chronic Diseases: Implications for Immune and Energy Homeostasis

Emerging evidence highlights the substantial role of the kynurenine pathway in various physiological systems and pathological conditions. Physical exercise has been shown to impact the kynurenine pathway in response to both single (acute) and multiple (chronic) exercise training stimuli. In this perspective article, we briefly outline the current knowledge concerning exercise-induced modulations of the kynurenine pathway and discuss underlying mechanisms. Furthermore, we expose the potential involvement of exercise-induced kynurenine pathway modulations on energy homeostasis (eg, through de novo synthesis of NAD+) and finally suggest how these modulations may contribute to exercise-induced benefits in the prevention and treatment of chronic diseases.

Cellular immune response to acute exercise: Comparison of endurance and resistance exercise

OBJECTIVES

Exercise-induced cellular mobilization might play a role in treatment and prevention of several diseases. However, little is known about the impact of different exercise modalities on immune cell mobilization and clinical cellular inflammation markers. Therefore, the present study aimed to investigate differences between acute endurance exercise (EE) and resistance exercise (RE) on cellular immune alterations.

METHODS

Twenty-four healthy men conducted an acute EE (cycling at 60% of peak power output) and RE (five exercise machines at 70% of the one-repetition maximum) session lasting 50 minutes in randomized order. Blood samples were collected before, after and one hour after exercise cessation. Outcomes included counts and proportions of leukocytes, neutrophils (NEUT), lymphocytes (LYM), LYM subsets, CD4/CD8 ratio, and the clinical cellular inflammation markers NEUT/LYM ratio (NLR), platelets/LYM ratio (PLR), and systemic immune inflammation index (SII).

RESULTS

Alterations in all outcomes were revealed except for CD8⁺ T cells, CD4/CD8 ratio, NLR, and PLR. EE induced a stronger cellular immune response and provoked alterations in more immune cell populations than RE. SII was altered only after EE.

CONCLUSION

An acute EE session causes a stronger mobilization of immune cells than RE. Additionally, SII represents an integrative marker to depict immunological alterations.

Physical Activity for the Treatment of Adolescent Depression: A Systematic Review and Meta-Analysis

Background: A noticeable proportion of adolescents with depression do not respond to guideline recommended treatment options. This systematic review and meta-analysis investigated the effectiveness of physical activity interventions as an alternative or complementary treatment for adolescents (12-18 years) with depression. The characteristics of the physical activity treatment that were most effective in reducing symptoms in adolescents with depression and the impact of methodological shortcomings in the existing research were also examined. Methods: Medline, PsycINFO, SPORTDiscus, ProQuest, and CENTRAL were searched for eligible records. Effect size estimates were pooled based on the application of a random-effects model. Potential moderation by physical activity characteristics (i.e., intensity, type, context, and time frame) and methodological features (i.e., type of control group and diagnostic tool to identify depression at baseline) was investigated by means of subgroup analyses and meta-regressions. The certainty of evidence was assessed by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. The primary outcome was the antidepressant effect of physical activity at postintervention measurement time point. As secondary outcomes, the sustainability of effects after the end of physical activity treatment and the acceptability of physical activity treatments were assessed. Overall, 10 studies were included in the qualitative synthesis and 9 studies involving 431 patients were included in the quantitative synthesis. Results: A moderate, significant antidepressant effect of physical activity was found (Hedges' g = -0.47, 95% CI = -0.71 to -0.24). Heterogeneity was small (T2 = 0.0313, I 2 = 27%, p = 0.18). However, the certainty of evidence was downgraded to low because the included studies contained serious methodological limitations. Moderator analyses revealed that session intensity significantly moderated the antidepressant effect of physical activity. Moreover, noticeably smaller effect sizes were found in studies that used non-physical activity sham treatments as control treatments (e.g., playing board games), compared to studies that used no control group treatments. Only three studies assessed the sustainability of effects after the end of physical activity treatment. The results suggest that the antidepressant effects further increase after the end of physical activity interventions. There was no significant difference in dropout risk between the physical activity and control groups. Conclusions: This review suggests that physical activity is effective in treating depression in adolescents. Physical activity sessions should be at least moderately intense [rate of perceived exertion (RPE) between 11 and 13] to be effective. Furthermore, our results suggest that physical activity treatments are well accepted. However, the low methodological quality in included studies might have led to effect overestimation. Therefore, more studies with higher methodological quality are needed to confirm the recommendation for physical activity treatments in adolescents with depression.

Exercise and the Kynurenine pathway: Current state of knowledge and results from a randomized cross-over study comparing acute effects of endurance and resistance training

INTRODUCTION

The essential amino acid tryptophan (TRP) is primarily degraded through the kynurenine (KYN) pathway, which is dysregulated in several chronic diseases. KYN pathway metabolites have immune- and neuro-modulatory properties and are involved in th de novo synthesis of nicotinamide adenine dinucleotide (NAD+). Currently, little evidence exists demonstrating that physical exercise may influence this pathway. However, differences between acute and chronic stimuli as well as the influence of exercise modalities remain to be investigated. Here, we provide an overview of existing studies and present results of a randomized cross-over trial on acute effects of a single-bout of resistance and endurance exercise.

METHODS

24 healthy male adults conducted both an acute endurance exercise (EE) and resistance exercise (RE) session. Blood samples were collected before, immediately after and one hour after cessation of each exercise session. Outcomes comprised serum levels of TRP, KYN, kynurenic acid (KA), quinolinic acid (QA) and calculated ratios. Gene expression of the enzymes indoleamine 2,3 dioxygenase (IDO) 1 and kynurenine aminotransferase (KAT) 4 was measured in peripheral blood mononuclear cells (PBMCs). Moreover, serum concentrations of the potential KYN pathway mediators interleukin (IL)-6 and cortisol were determined. Finally, we investigated baseline correlations between immune cell subsets, potential mediators and initial KYN pathway activation outcomes.

RESULTS

The KYN/TRP ratio correlated positively with IL-6 and CD56bright NK-cells and negatively with CD56dim NKcells. Expression of IDO1 in PBMCs correlated positively with IL-6, regulatory T-cells and CD56bright NK-cells, whereas negative correlations to cytotoxic T-cells and CD56dim NKcells were revealed. A significant time effect on KYN/TRP ratio was detected for RE. Regarding KA and KA/KYN ratio, an increase after exercise followed by a decrease at the follow- up measurement was revealed in EE. KAT4 expression also increased after exercise in EE. Moreover, elevated QA levels were observed after the EE session.

CONCLUSIONS

In contrast to chronic exercise interventions, single-bouts of endurance exercise provoke acute alterations on KYN pathway outcomes in humans. Our results indicate that EE induces stronger alterations than RE. Enhanced conversion of KYN to both, KA and QA suggest a peripheral KYN clearance, thereby preventing pathological accumulation within the CNS. Future acute and chronic exercise studies are needed to examine the role of NAD+ synthesis starting with TRP and the interplay between KYN pathway activation and mid- to long-term immunological modulations.

Influence of combined functional resistance and endurance exercise over 12 weeks on matrix metalloproteinase-2 serum concentration in persons with relapsing-remitting multiple sclerosis - a community-based randomized controlled trial

BACKGROUND

The relevance of regular moderate to intense exercise for ameliorating psychomotor symptoms in persons with multiple sclerosis (pwMS) is becoming increasingly evident. Over the last two decades, emerging evidence from clinical studies and animal models indicate immune regulatory mechanisms in both periphery and the central nervous system that may underlie these beneficial effects. The integrity of the blood-brain barrier as the main structural interface between periphery and brain seems to play an important role in MS. Reducing the secretion of proteolytic matrix metalloproteinases (MMP), i.e. MMP-2, as disruptors of blood-brain barrier integrity could have profound implications for MS.

METHODS

In this two-armed randomized controlled trial 64 participants with relapsing-remitting MS (RRMS) (EDSS 0-4.0) will be allocated to either an intervention group or a passive wait list control group. The intervention group will perform 60 min of combined functional resistance and endurance exercises 3x per week over a period of 12 weeks in a community-based and publicly available setting. Changes in serum concentration of MMP-2 will be the primary outcome. Secondary outcomes are numbers of immune cell subsets, soluble (anti-) inflammatory factors, physical capacity, cognitive performance, physical activity behavior, gait performance, and patient-reported outcomes. All outcome measures will be assessed at baseline and after week 12 with an additional blood sampling before, during and immediately after a single training session in week 6.

DISCUSSION

To our knowledge, this will be the first RCT to investigate both the acute and chronic effects of a community-based intense functional resistance and endurance exercise regimen in persons with RRMS. Combining analysis of biological and cognitive or psychological outcomes may provide a better understanding of the MS-specific symptomology.

TRIAL REGISTRATION

DRKS00017091; 05th of April, 2019; International Clinical Trials Registry Platform.

Do Acute Exercise-Induced Activations of the Kynurenine Pathway Induce Regulatory T-Cells on the Long-Term? - A Theoretical Frame Work Supported by Pilot Data

Regular physical activity and exercise interventions are suspected to have anti-inflammatory effects depending on exercise modality, thereby potentially reducing the risk and progress of several chronic diseases. Alterations in the kynurenine pathway may represent a link between inflammatory responses following acute exercise and chronic anti-inflammatory properties, such as increased levels of regulatory T-cells (T_reg). Here, we hypothesize that acute exercise activates the kynurenine pathway and physical fitness is associated with proportions of circulating anti-inflammatory T_reg in older healthy women. Nineteen older healthy female participants (55 years (SD: ± 5.6)) completed a cardiopulmonary incremental exercise test (CPET) with spirometry on a bicycle ergometer until exhaustion with maximum oxygen uptake (VO₂max) as outcome. Blood samples were taken before (T0) and one minute after (T1) the CPET. Levels of tryptophan, serotonin and kynurenine were determined by enzyme-linked immunosorbent assays. Flow cytometry was used to identify proportions of T-cell subsets. Both, kynurenine (p = 0.003, d = 0.40) and the kynurenine/tryptophan ratio (p = 0.034, d = 0.48) increased significantly after acute exercise. Moreover, participants` VO₂max was strongly correlated with T_reg levels (p < 0.001, r = 0.689). This is the first study indicating a kynurenine pathway activation following acute exercise in older healthy women. The observed correlation between T_reg levels and VO₂max emphasizes a potential link between short-term upregulated kynurenine levels and longer-term anti-inflammatory properties of exercise. Future research is needed to clarify to what extend acute exercise-induced activations of the kynurenine pathway contribute to T_reg differentiation.

Effects and Moderators of Acute Aerobic Exercise on Subsequent Interference Control: A Systematic Review and Meta-Analysis

Background: Acute aerobic exercise leads to positive physiological adaptations within the central nervous system. These findings inspired research on potential cognitive benefits following acute aerobic exercise. The effects of acute aerobic exercise on subsequent cognitive performance, by far, have been the most researched for interference control, a subcomponent of executive function. The results of primary studies on the effects of acute aerobic exercise on subsequent interference control performance are inconsistent. Therefore, we used meta-analytic methods to pool available effect sizes, and to identify covariates that determine the magnitude of exercise-induced interference control benefits. Methods: Medline, PsycINFO, and SPORTDiscus were searched for eligible records. Hedges' g corrected standardized mean difference values (SMDs) were used for analyses. Random-effects weights were used to pool effect sizes. Moderator analyses were conducted using meta-regressions and subgroups analyses. Covariates that were here tested for moderation included parameters of the applied exercise regimen (exercise intensity and exercise duration), characteristics of examined participants (age and fitness), and methodological features of existing research (type of control group, familiarization with test procedure, type of test variable, delay between exercise cessation, and testing). Results: Fifty studies, with data from 2,366 participants, were included in qualitative and quantitative synthesis. A small, significant beneficial effect of acute aerobic exercise on time-dependent measures of interference control was revealed (k = 49, Hedges' g = -0.26, 95%CI: -34 to -0.18). Effect sizes from time-dependent measures of interference control varied widely and heterogeneity reached statistical significance (T 2 = 0.0557, I 2 = 28.8%). Moderator analyses revealed that higher exercise intensities (vigorous intensity and high-intensity interval training), also participants at younger or older age, and participants who are familiar with the testing procedure prior to the experiment, benefitted most from acute aerobic exercise. However, noticeable heterogeneity remained unexplained within specific subgroups (high-intensity interval training, preadolescent children, and active and supervised control group). Conclusion: Acute aerobic exercise improves subsequent interference control performance. However, the covariates exercise intensity, participants' age, and familiarization with testing procedure determine the magnitude of that effect. Methodological features were not found to influence the magnitude of effects. This dismisses some doubts that exercise induced benefits for interference control performance are scientific artifacts. The fact that large heterogeneity remained unexplained in some subgroups indicates the need for further research on covariates within these subgroups. It should be noted that effect sizes for all analyses were small.

Aqua cycling for immunological recovery after intensive, eccentric exercise

PURPOSE

Alterations in immunological homeostasis induced by acute exercise have been frequently reported. In view of the growing amount of repetitive exercise stimuli in competitive sports, quick recovery plays a superior role. Therefore, we examined whether aqua cycling affects cellular immunological recovery.

METHODS

After performing 300 countermovement jumps with maximal effort male sport students (n = 20; 24.4 ± 2.2 years) were randomized into either an aqua cycling (AC) or a passive recovery (P) group. AC pedaled in chest-deep water without resistance, while P lay in a supine position. Each recovery protocols lasted 30 min. Blood samples were taken at Baseline, Post-exercise, Post-recovery and 1 h (h), 2 h, 4 h, 24 h, 48 h and 72 h after recovery. Outcomes comprised white blood cell (WBC) counts, lymphocyte (LYM) counts and LYM subsets (CD4/CD8 ratio). Additionally, cellular inflammation markers (neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and systemic immune-inflammation index (SII)) were calculated.

RESULTS

In both groups, WBC, NLR and SII were significantly increased compared to Baseline up to and including 4 h after recovery. Significant interaction effects were found for WBC (Post-recovery, 2 h and 4 h), NLR (Post-recovery), SII (Post-recovery) and CD4/CD8 ratio (2 h) with values of AC being higher than of P.

CONCLUSIONS

Interestingly, AC provoked a stronger but not prolonged immunological disturbance than P. NLR and SII may present simple, more integrative markers to screen exercise-induced alterations in immune homeostasis/recovery in athletes and clinical populations. More research is warranted to elucidate the clinical and practical relevance of these findings.

Influence of different rehabilitative aerobic exercise programs on (anti-) inflammatory immune signalling, cognitive and functional capacity in persons with MS - study protocol of a randomized controlled trial

BACKGROUND

Studies have shown positive effects of therapeutic exercise on motor- and cognitive function as well as on psychosocial outcomes in persons with multiple sclerosis (MS). A reduction of inflammatory stress through physical exercise has been suspected as one key mechanism, mediating the positive effects of exercise in the context of MS. The primary objective of this trial is to investigate the acute and chronic effects of different exercise modalities on (anti-)inflammatory immune signalling as well as on cognitive and functional capacity in persons with MS.

METHODS

A two armed single-blind randomized controlled design will investigate 72 persons with relapsing remitting or secondary progressive MS (EDSS 3.0-6.0), during 3 weeks of inpatient rehabilitation. Participants will be randomized into either a high-intensity interval training (HIIT) or a moderate continuous training group; the latter represents the local standard therapy (ST). Both groups will exercise 3x per week. The HIIT group will perform 5 × 1.5-min high-intensive exercise bouts at 95-100% of their maximum heart rate (HRmax) followed by active breaks of unloaded pedalling (60% HRmax) for 2 min. In contrast, the ST group will exercise for 24 min continuously at 65% of HRmax. The proportion of circulating regulatory T-cells will be measured as primary outcome. Secondary outcomes comprise numbers and proportions of further immune cells including Th17-cells, soluble factors ((anti-) inflammatory cytokines, tryptophan metabolites), endurance capacity, cognitive performance, processing skills for activities of daily living, fatigue, depression and healthcare-related quality of life. Outcomes will be assessed before (T0) and after (T3) the 3-week exercise intervention program. Blood samples of T0 will be taken immediately before the first exercise session. Additionally, blood samples for the soluble factors will be collected immediately after (T1) and three hours (T2) after the first exercise session of each group.

DISCUSSION

This study will be the first to investigate both acute and chronic effects of aerobic exercise on immune function and disease associated biomarkers in persons with MS. Combining biological analyses with cognitive and functional capacity assessments may contribute to a better understanding of responses to rehabilitative training, needed to improve exercise recommendations for persons with MS.

TRIAL REGISTRATION

This trial was prospectively registered at ClinicalTrials.gov ( NCT03652519 ; 29 August 2018).

Protocol for the "Chemobrain in Motion - study" (CIM - study): a randomized placebo-controlled trial of the impact of a high-intensity interval endurance training on cancer related cognitive impairments in women with breast cancer receiving first-line chemotherapy

BACKGROUND

Up to 80% of breast cancer patients suffer from Cancer Related Cognitive Impairments (CRCI). Exercise is suggested as a potential supportive care option to reduce cognitive decline in cancer patients. This study will investigate the effects of a high-intensity interval endurance training (HIIT) on CRCI in breast cancer patients. Potentially underlying immunological and neurobiological mechanisms, as well as effects on patients' self-perceived cognitive functioning and common cancer related side-effects, will be explored.

METHODS

A single-blinded randomized controlled trial will be carried out. The impact of HIIT on CRCI will be compared to that of a placebo-intervention (supervised myofascial release training). Both interventions will be conducted simultaneously with the patients' first-line chemotherapy treatment typically lasting 12-18 weeks. Fifty-nine women with breast cancer will be included in each of the two groups. The study is powered to detect (α = .05, β = .2) a medium effect size difference between the two groups (d = .5) in terms of patients' change in cognitive testing performances, from baseline until the end of the exercise-intervention. The cognitive test battery, recommended by the International Cancer and Cognition Task Force to assess CRCI, will be used as primary measure. This includes the Hopkins Verbal Learning Test (learning/verbal memory), the Controlled Oral Word Association Test (verbal fluency) and the Trail-Making-Test A/B (attention/set-switching). The following endpoints will be assessed as secondary measures: Go-/No-Go test performance (response inhibition), self-perceived cognitive functioning, serum levels of pro- and antiinflammatory markers (tumor necrosis factor alpha, Interleukin-6, Interleukin-1 alpha, Interleukin-1 beta, C-reactive protein, Interleukin-1 receptor antagonist and Interleukin-10), serum levels of neurotrophic and growth factors (brain-derived neurotrophic factor, insulin-like growth factor 1 and vascular endothelial growth factor), as well as common cancer-related side effects (decrease in physical capacity, fatigue, anxiety and depression, sleep disturbances, quality of life and chemotherapy compliance).

DISCUSSION

This study will provide data on the question whether HIIT is an effective supportive therapy that alleviates CRCI in breast cancer patients. Moreover, the present study will help shed light on the underlying mechanisms of potential CRCI improving effects of exercise in breast cancer patients.

TRIAL REGISTRATION

DRKS.de, German Clinical Trials Register (DRKS), ID: DRKS00011390 , Registered on 17 January 2018.

Influence of Personalized Exercise Recommendations During Rehabilitation on the Sustainability of Objectively Measured Physical Activity Levels, Fatigue, and Fatigue-Related Biomarkers in Patients With Breast Cancer

Purpose. Only one-third of patients with breast cancer reach the recommended activity level of 15 to 25 MET h/wk. The aim of this study was to determine the influence of personalized exercise recommendations during rehabilitation on patients’ physical activity level, fatigue, and self-perceived cognitive function as well as on side effect–associated biomarkers. Methods. Total metabolic rate, physical activity level, mean MET and steps, fatigue, self-perceived cognitive functioning , and biomarkers (C-reactive protein [CRP], interleukin 6, macrophage migration inhibiting factor [MIF], tumor necrosis factor [TNF]-α, brain-derived neurotrophic factor [BDNF], insulin-like growth factor 1 [IGF1]) were assessed in 60 patients with breast cancer in the aftercare phase before (t₀) and 8 months after (t₁) the intervention. The rehabilitation program consisted of an initial 3-week period and a 1-week stay after 4 months. Results. Paired t-test indicated a statistically significant increase in all activity outcomes from t₀ to t₁. Patients’ mean activity level significantly increased from 14.89 to 17.88 MET h/wk. Fatigue and self-perceived cognitive functioning significantly improved from t₀ to t₁. CRP levels significantly decreased, and BDNF as well as IGF1 levels significantly increased over time. Correlation analysis revealed statistically significant negative associations between fatigue, physical activity, and markers of inflammation (TNF-α and MIF). Furthermore, significant positive correlations between subjective cognitive functioning and all dimensions of fatigue were observed. Conclusions. The results support the importance of personalized exercise recommendations to increase physical activity levels in patients with breast cancer. Furthermore, the results highlighti an association between physical activity, fatigue, and inflammation.