Acute high-intensity interval exercise reduces human monocyte Toll-like receptor 2 expression in type 2 diabetes

Unveiling the role of exercise in modulating plasma heat shock protein 27 levels: insights for exercise immunology and cardiovascular health

Cardiovascular disease is one of the leading causes of mortality worldwide, primarily driven by atherosclerosis, a chronic inflammatory condition contributing significantly to fatalities. Various biological determinants affecting cardiovascular health across different age and sex groups have been identified. In this context, recent attention has focused on the potential therapeutic and preventive role of increasing circulating levels of heat shock protein 27 (plasma HSP27) in combating atherosclerosis. Plasma HSP27 is recognized for its protective function in inflammatory atherogenesis, offering promising avenues for intervention and management strategies against this prevalent cardiovascular ailment. Exercise has emerged as a pivotal strategy in preventing and managing cardiovascular disease, with literature indicating an increase in plasma HSP27 levels post-exercise. However, there is limited understanding of the impact of exercise on the release of HSP27 into circulation. Clarifying these aspects is crucial for understanding the role of exercise in modulating plasma HSP27 levels and its potential implications for cardiovascular health across diverse populations. Therefore, this review aims to establish a more comprehensive understanding of the relationship between plasma HSP27 and exercise.

Inflammation in diabetes complications: molecular mechanisms and therapeutic interventions

At present, diabetes mellitus (DM) has been one of the most endangering healthy diseases. Current therapies contain controlling high blood sugar, reducing risk factors like obesity, hypertension, and so on; however, DM patients inevitably and eventually progress into different types of diabetes complications, resulting in poor quality of life. Unfortunately, the clear etiology and pathogenesis of diabetes complications have not been elucidated owing to intricate whole-body systems. The immune system was responsible to regulate homeostasis by triggering or resolving inflammatory response, indicating it may be necessary to diabetes complications. In fact, previous studies have been shown inflammation plays multifunctional roles in the pathogenesis of diabetes complications and is attracting attention to be the meaningful therapeutic strategy. To this end, this review systematically concluded the current studies over the relationships of susceptible diabetes complications (e.g., diabetic cardiomyopathy, diabetic retinopathy, diabetic peripheral neuropathy, and diabetic nephropathy) and inflammation, ranging from immune cell response, cytokines interaction to pathomechanism of organ injury. Besides, we also summarized various therapeutic strategies to improve diabetes complications by target inflammation from special remedies to conventional lifestyle changes. This review will offer a panoramic insight into the mechanisms of diabetes complications from an inflammatory perspective and also discuss contemporary clinical interventions.

The effect of different high-intensity interval training protocols on cardiometabolic and inflammatory markers in sedentary young women: A randomized controlled trial

Few studies have reported the cardiovascular health effects of different high-intensity interval training (HIIT) protocols among sedentary young women. We investigated the impact of a traditional HIIT programme and a high-intensity circuit training (HICT) programme on lipid profiles and inflammatory cytokine levels in sedentary young women. Forty-two women were randomly assigned to HICT (body weight-based training), HIIT (cycling-based training), or control groups (n = 14 each). HICT and HIIT participants completed an 8-week training programme of three sessions per week. Total cholesterol (TC), triglyceride, high- and low-density lipoprotein, leptin, resistin, tumour necrosis factor-alpha (TNF-α), interleukin-8, and interferon-gamma levels were measured before and after the intervention. Post-intervention, TC and leptin were decreased in the HICT group. The HICT group also demonstrated increased lean mass, upper and lower limb strength, and balance, while the HIIT group displayed improved lower limb strength. Additionally, the control group showed significant increases in triglyceride levels, weight, body mass index, and fat mass. In conclusion, although both HICT and HIIT interventions showed improvements in cardiovascular health and physical fitness, participants in the HICT group experienced more health benefits.

Resistance exercise training augments the immunomodulatory adaptations to aerobic high-intensity interval training

To compare the effectiveness of different types of high-intensity interval training (HIIT) on meta-inflammation during obesity, TLR4 pathway activities were assessed following a 10-week randomized trial. 30 young females with overweight and obesity were randomly allocated to aerobic HIIT (HIIT/AE) or resistance exercise in HIIT (HIIT/RE) and performed a 28-minute (4 × 4 min) in each session. During each interval, the HIIT/AE performed four minutes of all-extremity cycling, whereas the HIIT/RE completed four minutes of combined resistance exercises and all-extremity cycling. The TLR4 pathway gene expression was measured for the TLR4 receptor, downstream adaptors (TIR domain-containing adaptor-inducing interferon-β (TRIF) and myeloid differentiation factor (MYD) 88), transcriptional factors (nuclear factor kappa B (NF-κB), and interferon regulatory factor (IRF) 3), and its negative regulator (tumor necrosis factor (TNF) a-induced protein 3 (TNFAIP3)). The serum levels of TNFα, interferon (IFN) γ, interleukin (IL)-10, and adiponectin were measured. We found that TLR4 (HIIT/RE: 0.6 ± 0.43 vs. HIIT/AE: 1.24 ± 0.82, p = 0.02), TRIF (HIIT/RE: 0.51 ± 0.4 vs. HIIT/AE: 3.56 ± 0.52, p = 0.001), and IRF3 (HIIT/RE: 0.49 ± 0.42 vs. HIIT/AE: 0.6 ± 0.89; p = 0.04) levels were significantly downregulated in HIIT/RE compared to the HIIT/AE, with a significant reduction in serum levels of TNFα (pg/ml) (HIIT/RE: 22.5 ± 11.3 to 6.3 ± 5.3 vs. HIIT/AE: 19.16 ± 20.8 to 13.48 ± 21.7, p = 0.04) and IFNγ (pg/ml) (HIIT/RE: 43.5 ± 20.6 to 37.5 ± 4.3 vs. HIIT/AE: 37.6 ± 5.6 to 68.1 ± 22.5, p = 0.03). Adiponectin and IL-10 levels did not significantly differ between the two groups. Thus, resistance exercise training augments the immunomodulatory adaptations to HIIT and should be prescribed to people at risk of cardiometabolic disease.Highlights HIIT in combination with resistance exercise looks more effective than HIIT alone to target TLR4-mediated inflammation in individuals with overweight and obesity.HIIT/RE induces a different effect on two downstream cascades of TLR4, leading to a greater overall reduction of TRIF-dependent pathway activities compared to MYD88.Both HIIT protocols show comparable effects on the negative regulatory protein TNFAIP3 gene expression.

Is moderate-intensity interval training more tolerable than high-intensity interval training in adults with obesity?

Interval training (IT) has been shown to be a time-effective alternative to traditional training programmes in the management of obesity. Nevertheless, studies comparing the effects of different IT intensities on inflammation, muscle and liver damage, and perceptual responses in people with obesity are relatively scarce. This study aimed to compare the acute effects of two different IT protocols matched by the mean load and duration on biochemical and perceptual responses in sedentary adults with obesity. Twenty-two volunteers (age = 33.40 ± 10.01 years, BMI = 38.29 ± 7.09 kg/m²) were randomized to perform two conditions: moderate-intensity IT (MIIT) 5 × 3 min (70% of peak power output (PPO))/2 min (45%PPO) and high-intensity IT (HIIT) 8 × 1 min (90%PPO)/2 min (45%PPO). Blood samples were drawn before and after exercise for biochemical and haematological measurements. Rating of perceived exertion (RPE) was assessed during and after exercise. Perceptual pain was evaluated before, throughout and after exercise. C-reactive protein, white blood cells and neutrophils increased only after HIIT (p < 0.001, for all). Aspartate aminotransferase, alanine aminotransferase, creatine kinase and lactate dehydrogenase increased in both HIIT and MIIT (p < 0.001, for all), without any difference between sessions. HIIT induced a greater increase of blood lactate compared to MIIT (p < 0.05). Pain and RPE scores were higher during HIIT vs. MIIT (p < 0.001 and p < 0.01, respectively). MIIT induced fewer immune system perturbations and less muscle pain and was perceived as more tolerable compared to HIIT session. Therefore, MIIT could be used as a first step to promote body adaptations before starting a HIIT programme in sedentary people with obesity.

Cardiorespiratory fitness in individuals with type 2 diabetes mellitus: a systematic review and meta-analysis

Objective

To conduct a systematic review and meta-analysis assessing the cardiorespiratory fitness (CRF) among individuals with and without type 2 diabetes.

Materials and methods

The current review was registered in PROSPERO under the number CRD42018082718. MEDLINE, EMBASE, and Cochrane Library databases were searched from inception through February 2022. Eligibility criteria consisted of observational or interventional studies that evaluated CRF through cardiopulmonary exercise testing or six-minute walk test in individuals with type 2 diabetes compared with individuals without type 2 diabetes. For data extraction, we used baseline CRF assessments of randomized clinical trials or follow-up CRF assessments in observational studies. We performed a meta-analysis using maximal oxygen consumption (VO2 max), and distance walked in the 6MWT as primary outcomes. They were extracted and expressed as mean differences (MDs) and 95% CIs between treatment and comparator groups. The meta-analysis was conducted using Review Manager (RevMan) software.

Results

Out of 8,347 studies retrieved, 77 were included. Compared with individuals without type 2 diabetes, individuals with diabetes achieved a lower VO2 max (-5.84 mL.kg-1.min-1, 95% CI -6.93, -4.76 mL.kg-1.min-1, p = <0.0001; I2 = 91%, p for heterogeneity < 0.0001), and a smaller distance walked in 6MWT (-93.30 meters, 95% CI -141.2, -45.4 meters, p > 0.0001; I2: 94%, p for heterogeneity < 0.0001).

Conclusion

Type 2 diabetes was associated with lower cardiorespiratory fitness, as observed by lower VO2 max on maximal tests, and smaller distance walked in 6MWT, however the quality of studies was low.

Effects of high-intensity interval training (HIIT) on skeletal muscle atrophy, function, and myokine profile in diabetic myopathy

PURPOSE

Diabetes is a metabolic disorder characterized by chronic hyperglycemia due to insulin deficiency and/or loss of its action. Diabetic myopathy causes functional limitations in diabetic patients. The beneficial effects of high-intensity interval training (HIIT) are widely reported. We have hypothesized that HIIT application would prevent the development of diabetic myopathy.

METHODS

Male, Wistar albino rats (10 W) were randomly divided into four groups (1)Control(C), (2)Diabetes(DM), (3)Training(HIIT), and (4)Diabetes + Training(DM + HIIT). Streptozotocin(60 mg/kg) was injected for the induction of diabetes. The maximum exercise capacity(MEC) of animals was determined by an incremental load test. HIIT protocol (4 min 85-95 % MEC, 2 min 40-50 % MEC, 6 cycles, 5 days/week) was applied for 8 weeks. In the end, functional parameters, atrophy, and resistance to fatigue in soleus and EDL muscles were evaluated. IL-6, FNDC5, and myonectin levels were measured in EDL, soleus, and serum.

RESULTS

We observed atrophy, fatigue sensitivity, and proinflammatory alterations (IL-6 increase) in the EDL samples due to diabetic myopathy which were not observed in the soleus samples. HIIT application prevented the aforementioned detrimental alterations. Both force-frequency response and parallelly the twitch amplitude increased significantly in the DM + HIIT group. Half relaxation time (DT50) increased in both exercising and sedentary diabetics. FNDC5 was significantly higher in the exercising animals in soleus samples. Myonectin was significantly higher in the soleus muscle only in the DM + HIIT group.

CONCLUSION

Current findings show that diabetic myopathy develops earlier in glycolytic-fast-twitch fibers(EDL) than in oxidative-slow-twitch fibers(soleus). Furthermore, HIIT application prevents atrophy in skeletal muscle, increases resistance to fatigue, and has an anti-inflammatory effect.

NEW FINDINGS

The current study analyzes the myokine profile and skeletal muscle function under the effect of diabetes HIIT-type exercise. We also measured maximal exercise capacity and tailored the exercise program individually according to the result. Diabetic myopathy is an important complication of diabetes yet still, it is not understood completely. Our results show that HIIT-type training would be beneficial in diabetic myopathy but further investigation is needed to understand the whole molecular mechanism.

Effect of High-Intensity Interval Training on Fatty Infiltration After Delayed Rotator Cuff Repair in a Mouse Model

Background

Fatty infiltration (FI) of the rotator cuff muscles is correlated with shoulder function and retear rates after rotator cuff repair. High-intensity interval training (HIIT) induces beige adipose tissue to express more uncoupling protein 1 (UCP1) to consume lipids. The beta-3 adrenergic receptor (β3AR) is located on adipocyte membrane and induces thermogenesis.

Purpose

To test the role of HIIT in improving muscle quality and contractility in a delayed rotator cuff repair mouse model via β3AR.

Study Design

Controlled laboratory study.

Methods

Three-month-old C57BL/6J mice underwent a unilateral supraspinatus (SS) tendon transection with a 6-week delayed tendon repair. Mice ran on a treadmill with the HIIT program for 6 weeks after tendon transection or after delayed repair. To study the role of β3AR, SR59230A, a selective β3AR antagonist, was administered to mice 10 minutes before each exercise through intraperitoneal injection. The SS, interscapular brown adipose tissue (iBAT), and subcutaneous inguinal white adipose tissue (ingWAT) were harvested at the end of the 12th week after tendon transection and were analyzed by histology and Western blotting. Tests were performed to assess muscle contractility of the SS.

Results

Histologic analysis of SS showed that HIIT prevented and reversed muscle atrophy and FI. The contractile tests showed higher contractility of the SS in the HIIT groups than in the no-exercise group. In the HIIT groups, SS, iBAT, and ingWAT all showed increased expression of tyrosine hydroxylase, UCP1, and upregulated β3AR thermogenesis pathway. However, SR59230A inhibited HIIT, suggesting that the effect of HIIT depends on β3AR.

Conclusion

HIIT improved SS quality and function after delayed rotator cuff repair through a β3AR-dependent mechanism.

Clinical Relevance

HIIT may serve as a new rehabilitation method for patients with rotator cuff muscle atrophy and FI after rotator cuff repair to improve postoperative clinical outcomes.

Effects of weight-bearing vs. non-weight-bearing endurance exercise on reducing body fat and inflammatory markers in obese females

OBJECTIVES

Endurance exercise is an effective strategy for maintaining an anti-inflammatory environment and weight management. However, the effect of this type of exercise on decreasing body fat and TNF-α levels and increasing adiponectin levels is controversial. The aims of this study was to prove the effects of weight-bearing vs. non-weight-bearing endurance exercise on reducing body fat and inflammatory markers in obese females.

METHODS

24 obese adolescents were recruited from female students from the State University of Malang. The interventions given in this study were weight-bearing endurance exercise (WBEE), and non-weight-bearing endurance exercise (NWBEE). Serum TNF-α levels and serum adiponectin levels were evaluated using enzyme-linked immunosorbent assay (ELISA). Statistical analysis techniques use paired sample T-test with a significant level of 5%.

RESULTS

Results of the statistical analysis show that the average body fat (PBF, FM, FFM) and TNF-α levels before endurance exercise vs. after endurance exercise in both types of exercise experienced a significant decrease (p≤0.05), while average adiponectin levels in both types of exercise experienced a significant increase before endurance exercise vs. after endurance exercise (p≤0.001).

CONCLUSIONS

In general, it can be concluded that weight-bearing and non-weight-bearing endurance exercise with moderate-intensity for 40 min/exercise session reduce body fat and TNF-α levels and increase adiponectin levels as a marker of inflammation in obese female.

Physical Activity Maintain Immune Response Through TLR-2/TLR-4 Gene Expression in Type-2 Diabetes Mellitus Patient at Medan City

Background

The Increasing in type-2 diabetes mellitus (T2DM) needs to solve comprehensively and holistically. Patients with T2DM should have self-coping due to lifestyle modification. Abdominal fat accumulation can release pro-inflammatory cytokine that leads TLR-2 and TLR-4 to the response. These two kinds of toll-like receptors exist on the monocyte surface membrane which is an innate immunity cell.

Objective

The aims of this study were to get the profile of physical activity, metabolic state, and mononuclear cell response to the expression of the TLR2 and TLR4 genes in T2DM patients.

Methods

It was a descriptive-analytic study with a cross-sectional study design. Thirty-two eligible patients with inclusion criteria participated as subjects. All subjects answered questions by IPAQ, and checked metabolic state with body composition analysis. The TLR2 and TLR4 gene expression was determined with quantitative Real- Time PCR.

Results

This study result found that most T2DM patients were in a highly active category in which most of their activity was walking (light intensity). The average abdominal circumferences were 91.81 ± 15.4 cm, body fat percentage was 29.5 ± 8.8%, and fasting blood sugar was 187.07 ± 67.03 mg/dl. Mononuclear cells number were normal. The expression of the TLR2 gene was lower by 0.71 fold and TLR4 gene expression was lower by 0.9 fold compared with non-DM (p<0.05). By chi-square test, there was a positive correlation between TLR2 gene expression with fasting blood glucose (p=0.011, and a positive correlation between the abdominal circumference and TLR4 gene expression (p=0.011).

Conclusion

Type-2 Diabetes mellitus patients in primary health care keep walking as their physical activity to maintain blood glucose. Patients need to do moderate to vigorous exercise regularly to reduce body fat percentage especially abdominal fat to reduce Toll-like receptor gene expression, so insulin resistance and blood glucose level might decline to normal.

Acute Effects of High-Intensity Interval Training on Diabetes Mellitus: A Systematic Review

This study evaluated the scientific evidence on the acute effects of high-intensity interval training (HIIT) on biochemical, cardiovascular, and metabolic parameters in patients with diabetes mellitus. The research took place using two databases (PubMed and Google Scholar) with eligible studies conducted between 2010 and 2020, using the following keywords: (1) high-intensity training/exercise; (2) interval training/exercise; (3) HIIT/exercise; AND “diabetes”. Data extraction was then performed on the eligible studies through content analysis using the categories: author and year of publication; sample characteristics; methods and data collected; intervention protocol; and results found. Methodological quality was assessed using the PEDro scale. Fourteen studies were included, evaluating 168 people with diabetes (122/46 type 2/1) and 42 normoglycemic individuals, which evaluated markers such as capillary and fasting blood glucose, 24-h blood glucose profile, postprandial blood glucose, incidence, and prevalence of hyperglycemia, vascular function and pressure response and control of inflammatory markers. Physical exercise was found to have several acute beneficial effects on the health of the diabetic population, such as reduced capillary and postprandial blood glucose, blood glucose profile, and blood pressure. Moreover, HIIT seems to be a safe and effective alternative in glycemic control and associated factors, superior to continuous moderate-intensity training.

The Molecular Signature of High-intensity Training in the Human Body

High-intensity training is becoming increasingly popular outside of elite sport for health prevention and rehabilitation. This expanded application of high-intensity training in different populations requires a deeper understanding of its molecular signature in the human body. Therefore, in this integrative review, cellular and systemic molecular responses to high-intensity training are described for skeletal muscle, cardiovascular system, and the immune system as major effectors and targets of health and performance. Different kinds of stimuli and resulting homeostatic perturbations (i. e., metabolic, mechanical, neuronal, and hormonal) are reflected, taking into account their role in the local and systemic deflection of molecular sensors and mediators, and their role in tissue and organ adaptations. In skeletal muscle, a high metabolic perturbation induced by high-intensity training is the major stimulus for skeletal muscle adaptation. In the cardio-vascular system, high-intensity training induces haemodynamic stress and deflection of the Ca 2+ handling as major stimuli for functional and structural adaptation of the heart and vessels. For the immune system haemodynamic stress, hormones, exosomes, and O2 availability are proposed stimuli that mediate their effects by alteration of different signalling processes leading to local and systemic (anti)inflammatory responses. Overall, high-intensity training shows specific molecular signatures that demonstrate its high potential to improve health and physical performance.

A Guide to Different Intensities of Exercise, Vaccination, and Sports Nutrition in the Course of Preparing Elite Athletes for the Management of Upper Respiratory Infections during the COVID-19 Pandemic: A Narrative Review

Elite athletes use high-intensity training to maintain their fitness level. However, intense training can harm the immune system, making athletes suspectable to COVID-19 and negatively affecting their performance. In addition, the diet of athletes should be appreciated more as it is another influencer of the immune system, especially during the COVID 19 pandemic. The other important issue elite athletes face currently is vaccination and its possible intervention with their training. The present study attempts to discuss the impact of different training intensities, nutritional strategies, and vaccination on the immune system function in elite athletes. To this end, Scopus, ISC, PubMed, Web of Science, and Google Scholar databases were searched from 1988 to 2021 using the related keywords. The results of our review showed that although high-intensity exercise can suppress the immune system, elite athletes should not stop training in the time of infection but use low- and moderate-intensity training. Moderate-intensity exercise can improve immune function and maintain physical fitness. In addition, it is also better for athletes not to undertake high-intensity training at the time of vaccination, but instead perform moderate to low-intensity training. Furthermore, nutritional strategies can be employed to improve immune function during high-intensity training periods.

Type and Intensity as Key Variable of Exercise in Metainflammation diseases: A Review

Monocyte and lymphocyte subpopulations exhibit functions that vary between the anti- and pro-inflammatory spectrum, such as classic CD16- and non-classical CD16+ monocytes, as well as T helper 2 lymphocytes (Th2), the Th1/Th17 lymphocytes ratio, and T regulatory lymphocytes (Treg). Metabolic disease-associated inflammation is accompanied by an imbalance in monocyte and lymphocyte phenotypes and functionality, as well as a stronger proportion of inflammatory subpopulations. These changes appear to be important for the development and progression of diseases like diabetes and cardiovascular disease. On the other hand, the regular practice of physical exercise is an important tool to restore the functionality of monocytes and lymphocytes, and to balance the subtypes ratio. However, key variables regarding exercise prescription, such as the type of exercise, intensity, and volume differentially impact on the acute and chronic immune response in individuals diagnosed with meta inflammation diseases. Here, we discuss the impact of different physical exercise protocols, acutely and chronically, on monocytes and lymphocytes of individuals with metabolic disease-associated inflammation. In this review, we focus on the best effects of different exercise protocols to dose the "exercise pill" in different inflammatory status.

Interpreting 'anti-inflammatory' cytokine responses to exercise: focus on interleukin-10

Circulating concentrations of canonically pro- and anti-inflammatory cytokines are commonly measured when evaluating the anti-inflammatory effects of exercise. An important caveat to interpreting systemic cytokine concentrations as evidence for the anti-inflammatory effects of exercise is the observed dissociation between circulating cytokine concentrations and cytokine function at the tissue/cellular level. The dichotomization of cytokines as pro- or anti-inflammatory also overlooks the context dependence of cytokine function, which can vary depending on the physiological state being studied, the cytokine's cellular source/target, and magnitude of cytokine responses. We re-evaluate our current understanding of anti-inflammatory cytokine responses to exercise by highlighting nuances surrounding the interpretation of altered systemic cytokine concentrations as evidence for changes in inflammatory processes occurring at the tissue/cellular level. We highlight the lesser known pro-inflammatory and immunostimulatory actions of the prototypical anti-inflammatory cytokine, interleukin (IL)-10, including the potentiation of interferon gamma production during endotoxaemia, CD8⁺ T cell activation in tumour bearing rodents and cancer patients in vivo, and CD8⁺ T lymphocyte and natural killer cell activation in vitro. IL-10's more well-established anti-inflammatory actions can also be blunted following exercise training and under chronic inflammatory states such as type 2 diabetes (T2D) independently of circulating IL-10 concentrations. The resistance to IL-10's anti-inflammatory action in T2D coincides with blunted STAT3 phosphorylation and can be restored with small-molecule activators of IL-10 signalling, highlighting potential therapeutic avenues for restoring IL-10 action. We posit that inferences based on altered circulating cytokine concentrations alone can miss important functional changes in cytokine action occurring at the tissue/cellular level.

Toll-Like Receptors: Are They Taking a Toll on the Heart in Viral Myocarditis?

Myocarditis is an inflammatory disease of the heart with viral infections being the most common aetiology. Its complex biology remains poorly understood and its clinical management is one of the most challenging in the field of cardiology. Toll-like receptors (TLRs), a family of evolutionarily conserved pattern recognition receptors, are increasingly known to be implicated in the pathophysiology of viral myocarditis. Their central role in innate and adaptive immune responses, and in the inflammatory reaction that ensues, indeed makes them prime candidates to profoundly affect every stage of the disease process. This review describes the pathogenesis and pathophysiology of viral myocarditis, and scrutinises the role of TLRs in every phase. We conclude with directions for future research in this field.

Sedentary behavior, exercise and COVID-19: immune and metabolic implications in obesity and its comorbidities

Many reports showed a dramatic decrease in the levels of physical activity during the current pandemic of SARS-CoV-2. This has substantial immune and metabolic implications, especially in those at risk or with metabolic diseases including individuals with obesity and Type 2 diabetes. In this study we discussed the route from physical inactivity to immune and metabolic aberrancies; focusing on how insulin resistance could represent an adaptive mechanism to the low physical activity levels and on how such an adaptive mechanism could shift to a pathognomonic feature of metabolic diseases, creating a vicious circle of immune and metabolic aberrancies. We provide a theoretical framework to the severe immunopathology of COVID-19 in patients with metabolic diseases. We finally discuss the idea of exercise as a potential adjuvant against COVID-19 and emphasize how even interrupting prolonged periods of sitting with short time breaks of very light activity could be a feasible strategy to limit the deleterious effects of the outbreak.

Immunoregulation induced by autologous serum collected after acute exercise in obese men: a randomized cross-over trial

In this study, we evaluated the effects of autologous serum collected after two types of exercise on the in vitro inflammatory profile and T cell phenotype of resting peripheral blood mononuclear cells (PBMCs) in obese men. Serum samples and PBMCs were obtained from eight obese men who performed two exercise bouts—high intensity interval exercise (HIIE) and exhaustive exercise session to voluntary fatigue—in a randomized cross-over trial. Pre-exercise PBMCs were incubated with 50% autologous serum (collected before and after each exercise bout) for 4 h. In vitro experiments revealed that post-HIIE serum reduced the histone H4 acetylation status and NF-κB content of PBMCs and suppressed the production of both TNF-α and IL-6 by PBMCs, while increasing IL-10 production. Post-exhaustive exercise serum induced histone H4 hyperacetylation and mitochondrial depolarization in lymphocytes and increased TNF-α production. In vitro post-HIIE serum incubation resulted in an increase in the frequencies of CD4 + CTLA-4 + and CD4 + CD25+ T cells expressing CD39 and CD73. Post-exhaustive exercise serum decreased the frequency of CD4 + CD25 + CD73+ T cells but increased CD4 + CD25-CD39 + T cell frequency. Both post-exercise serums increased the proportions of CD4 + PD-1 + and CD8 + PD-1+ T cells. Blood serum factors released during exercise altered the immune response and T cell phenotype. The type of exercise impacted the immunomodulatory activity of the post-exercise serum on PBMCs.

Impact of combined training with different exercise intensities on inflammatory and lipid markers in type 2 diabetes: a secondary analysis from a 1-year randomized controlled trial

Background

Exercise is a well-accepted strategy to improve lipid and inflammatory profile in individuals with type 2 diabetes (T2DM). However, the exercise intensity having the most benefits on lipids and inflammatory markers in patients with T2DM remains unclear. We aimed to analyse the impact of a 1-year combined high-intensity interval training (HIIT) with resistance training (RT), and a moderate continuous training (MCT) with RT on inflammatory and lipid profile in individuals with T2DM.

Methods

Individuals with T2DM (n = 80, aged 59 years) performed a 1-year randomized controlled trial and were randomized into three groups (control, n = 27; HIIT with RT, n = 25; MCT with RT, n = 28). Exercise sessions were supervised with a frequency of 3 days per week. Inflammatory and lipid profiles were measured at baseline and at 1-year follow-up. Changes in inflammatory and lipid markers were assessed using generalized estimating equations.

Results

After adjusting for sex, age and baseline moderate-to-vigorous physical activity (MVPA), we observed a time-by-group interaction for Interleukin-6 (IL-6) in both the MCT with RT (β = − 0.70, p = 0.034) and HIIT with RT (β = − 0.62, p = 0.049) groups, whereas, only the HIIT with RT group improved total cholesterol (β = − 0.03, p = 0.045) and LDL-C (β = − 0.03, p = 0.034), when compared to control. No effect was observed for C-reactive protein (CRP), cortisol, tumour necrosis factor-α (TNF-α), soluble form of the haptoglobin-hemoglobin receptor CD163 (sCD163), triglycerides and HDL-C in both groups (p > 0.05).

Conclusions

Favorable adaptations on IL-6 were observed in both the HIIT and MCT combined with RT groups following a long-term 1-year exercise intervention in individuals with T2DM. However, only the HIIT with RT prevented further derangement of total cholesterol and LDL-C, when compared to the control group. Therefore, in order to encourage exercise participation and improve inflammatory profile, either exercise protocols may be prescribed, however, HIIT with RT may have further benefits on the lipid profile.

Trial registration Clinicaltrials.gov ID: NCT03144505

Toll-like Receptor as a Molecular Link between Metabolic Syndrome and Inflammation: A Review

Metabolic Syndrome (MetS) involves a cluster of five conditions, i.e. obesity, hyperglycaemia, hypertension, hypertriglyceridemia and low High-Density Lipoprotein (HDL) cholesterol. All components of MetS share an underlying chronic inflammatory aetiology, manifested by increased levels of pro-inflammatory cytokines. The pathogenic role of inflammation in the development of MetS suggested that toll-like receptor (TLR) activation may trigger MetS. This review summarises the supporting evidence on the interactions between MetS and TLR activation, bridged by the elevation of TLR ligands during MetS. The regulatory circuits mediated by TLR activation, which modulates signal propagation, leading to the state of chronic inflammation, are also discussed. Taken together, TLR activation could be the molecular basis in the development of MetS-induced inflammation.

The Molecular Adaptive Responses of Skeletal Muscle to High-Intensity Exercise/Training and Hypoxia

High-intensity exercise/training, especially interval exercise/training, has gained popularity in recent years. Hypoxic training was introduced to elite athletes half a century ago and has recently been adopted by the general public. In the current review, we have summarised the molecular adaptive responses of skeletal muscle to high-intensity exercise/training, focusing on mitochondrial biogenesis, angiogenesis, and muscle fibre composition. The literature suggests that (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) PGC-1α, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1-alpha (HIF1-α) might be the main mediators of skeletal muscle adaptations to high-intensity exercises in hypoxia. Exercise is known to be anti-inflammatory, while the effects of hypoxia on inflammatory signalling are more complex. The anti-inflammatory effects of a single session of exercise might result from the release of anti-inflammatory myokines and other cytokines, as well as the downregulation of Toll-like receptor signalling, while training-induced anti-inflammatory effects may be due to reductions in abdominal and visceral fat (which are main sources of pro-inflammatory cytokines). Hypoxia can lead to inflammation, and inflammation can result in tissue hypoxia. However, the hypoxic factor HIF1-α is essential for preventing excessive inflammation. Disease-induced hypoxia is related to an upregulation of inflammatory signalling, but the effects of exercise-induced hypoxia on inflammation are less conclusive. The effects of high-intensity exercise under hypoxia on skeletal muscle molecular adaptations and inflammatory signalling have not been fully explored and are worth investigating in future studies. Understanding these effects will lead to a more comprehensive scientific basis for maximising the benefits of high-intensity exercise.

Exercise-associated prevention of adult cardiovascular disease in children and adolescents: monocytes, molecular mechanisms, and a call for discovery

Atherosclerosis originates in childhood and adolescence. The goal of this review is to highlight how exercise and physical activity during childhood and adolescence, critical periods of growth and development, can prevent adult cardiovascular disease (CVD), particularly through molecular mechanisms of monocytes, a key cell of the innate immune system. Monocytes are heterogeneous and pluripotential cells that can, paradoxically, play a role in both the instigation and prevention of atherosclerosis. Recent discoveries in young adults reveal that brief exercise affects monocyte gene pathways promoting a cell phenotype that patrols the vascular system and repairs injuries. Concurrently, exercise inhibits pro-inflammatory monocytes, cells that contribute to vascular damage and plaque formation. Because CVD is typically asymptomatic in youth, minimally invasive techniques must be honed to study the subtle anatomic and physiologic evidence of vascular dysfunction. Exercise gas exchange and heart rate measures can be combined with ultrasound assessments of vascular anatomy and reactivity, and near-infrared spectroscopy to quantify impaired O2 transport that is often hidden at rest. Combined with functional, transcriptomic, and epigenetic monocyte expression and measures of monocyte-endothelium interaction, molecular mechanisms of early CVD can be formulated, and then translated into effective physical activity-based strategies in youth to prevent adult-onset CVD.

The Exercise Training Modulatory Effects on the Obesity-Induced Immunometabolic Dysfunctions

Reduced physical activity rate in people's lifestyle is a global concern associated with the prevalence of health disorders such as obesity and metabolic disturbance. Ample evidence has indicated a critical role of the immune system in the aggravation of obesity. The type, duration, and production of adipose tissue-released mediators may change subsequent inactive lifestyle-induced obesity, leading to the chronic systematic inflammation and monocyte/macrophage (MON/MФ) phenotype polarization. Preliminary adipose tissue expansion can be inhibited by changing the lifestyle. In this context, exercise training is widely recommended due to a definite improvement of energy balance and the potential impacts on the inflammatory signaling cascades. How exercise training affects the immune system has not yet been fully elucidated, because its anti-inflammatory, pro-inflammatory, or even immunosuppressive impacts have been indicated in the literature. A thorough understanding of the mechanisms triggered by exercise can suggest a new approach to combat meta-inflammation-induced metabolic diseases. In this review, we summarized the obesity-induced inflammatory pathways, the roles of MON/MФ polarization in adipose tissue and systemic inflammation, and the underlying inflammatory mechanisms triggered by exercise during obesity.

Combined All-Extremity High-Intensity Interval Training Regulates Immunometabolic Responses through Toll-Like Receptor 4 Adaptors and A20 Downregulation in Obese Young Females

Metainflammation and malfunctions of toll-like receptor 4 (TLR4) are related to obesity-induced immunometabolic morbidities. There are almost no studies relating exercise training to the TLR4 pathway and its adaptors and negative regulators. Thirty young women with obesity (exercise group and control group) were included in a 10-week all-extremity combined high-intensity interval training program. The immunomodulatory impacts of exercise on TLR4, its related adaptors (TIR domain-containing adaptor-inducing IFN-β[TRIF], myeloid differentiation factor 88 [MyD88],and tumor receptor-associated factor 6 [TRAF6]), transcriptional factors (nuclear factor [NF]-κB and interferon regulatory factor 3 [IRF3]), and negative regulator (A20) mRNA levels were assessed by real-time PCR. Also, the serum concentration of TLR4 final products (tumor necrosis factor α [TNFα] and interferon γ [IFNγ]) was measured by ELISA. Cardiorespiratory and body composition parameters were tested, as well. There was a significant improvement in body composition and cardiorespiratory fitness. This intervention downregulated TLR4 (from 2.25 ± 1.07 to 0.84 ± 1.01), MyD88 (from 4.53 ± 5.15 to 1.27 ± 0.88), NF-κB (from 1.61 ± 2.03 to 0.23 ± 0.39), IRF3 (from 1.22 ± 0.77 to 0.25 ± 0.36), and A20 (from 0.88 ± 0.59 to 0.22 ± 0.33) levels and reduced the TNFα concentrations (from 22.39 ± 11.43 to 6.26 ± 5.31) significantly in the exercise group, while no statistically significant change was found in TRIF and TRAF6 expression and IFNγ circulating levels. It is concluded that long-term exercise modifies the inflammatory pathways and modulates the immune function at the early stages of inflammation initiation in circulating immune cells. Accordingly, we suggest time-efficient exercise protocols as a possible therapy approach for the prevention of M1 polarization.

Inherited and Environmental Factors Influence Human Monocyte Heterogeneity

Blood monocytes develop in the bone marrow before being released into the peripheral circulation. The circulating monocyte pool is composed of multiple subsets, each with specialized functions. These cells are recruited to repopulate resident monocyte-derived cells in the periphery and also to sites of injury. Several extrinsic factors influence the function and quantity of monocytes in the blood. Here, we outline the impact of sex, ethnicity, age, sleep, diet, and exercise on monocyte subsets and their function, highlighting that steady state is not a single physiological condition. A clearer understanding of the relationship between these factors and the immune system may allow for improved therapeutic strategies.

Towards a personalised approach in exercise-based cardiovascular rehabilitation: How can translational research help? A 'call to action' from the Section on Secondary Prevention and Cardiac Rehabilitation of the European Association of Preventive Cardiology

The benefit of regular physical activity and exercise training for the prevention of cardiovascular and metabolic diseases is undisputed. Many molecular mechanisms mediating exercise effects have been deciphered. Personalised exercise prescription can help patients in achieving their individual greatest benefit from an exercise-based cardiovascular rehabilitation programme. Yet, we still struggle to provide truly personalised exercise prescriptions to our patients. In this position paper, we address novel basic and translational research concepts that can help us understand the principles underlying the inter-individual differences in the response to exercise, and identify early on who would most likely benefit from which exercise intervention. This includes hereditary, non-hereditary and sex-specific concepts. Recent insights have helped us to take on a more holistic view, integrating exercise-mediated molecular mechanisms with those influenced by metabolism and immunity. Unfortunately, while the outline is recognisable, many details are still lacking to turn the understanding of a concept into a roadmap ready to be used in clinical routine. This position paper therefore also investigates perspectives on how the advent of 'big data' and the use of animal models could help unravel inter-individual responses to exercise parameters and thus influence hypothesis-building for translational research in exercise-based cardiovascular rehabilitation.

Exercise as a prescription for patients with various diseases

A growing understanding of the benefits of exercise over the past few decades has prompted researchers to take an interest in the possibilities of exercise therapy. Because each sport has its own set of characteristics and physiological complications that tend to occur during exercise training, the effects and underlying mechanisms of exercise remain unclear. Thus, the first step in probing the effects of exercise on different diseases is the selection of an optimal exercise protocol. This review summarizes the latest exercise prescription treatments for 26 different diseases: musculoskeletal system diseases (low back pain, tendon injury, osteoporosis, osteoarthritis, and hip fracture), metabolic system diseases (obesity, type 2 diabetes, type 1 diabetes, and nonalcoholic fatty liver disease), cardio-cerebral vascular system diseases (coronary artery disease, stroke, and chronic heart failure), nervous system diseases (Parkinson's disease, Huntington's disease, Alzheimer's disease, depression, and anxiety disorders), respiratory system diseases (chronic obstructive pulmonary disease, interstitial lung disease, and after lung transplantation), urinary system diseases (chronic kidney disease and after kidney transplantation), and cancers (breast cancer, colon cancer, prostate cancer, and lung cancer). Each exercise prescription is displayed in a corresponding table. The recommended type, intensity, and frequency of exercise prescriptions are summarized, and the effects of exercise therapy on the prevention and rehabilitation of different diseases are discussed.

Maximal Exercise Alters the Inflammatory Phenotype and Response of Mononuclear Cells

PURPOSE

Monocytes express the CD14 receptor that facilitates lipopolysaccharide (LPS) ligation to toll-like receptor 4 (TLR4) to elicit production of interleukin (IL)-6, IL-10, and tumor necrosis factor alpha (TNF-α). However, proinflammatory conditions, such as strenuous exercise, increase the percentage of monocytes expressing CD16, a receptor that enhances LPS stimulated TNF-α production. Therefore, we examined whether maximal treadmill exercise would alter the inflammatory phenotype of classical (CD14/CD16) and proinflammatory monocytes (intermediate [CD14/CD16] and nonclassical [CD14/CD16]), evidenced by changes in TLR4, CD14, and CD16 receptor expression, and their inflammatory response to ex vivo LPS stimulation.

METHODS

Human mononuclear cells from 25 male participants (age, 24.2 ± 4.0 yr) were isolated before and after exercise to assess TLR4, CD14, and CD16 expression by flow cytometry and ex vivo production of LPS-stimulated inflammatory cytokines (IL-6, IL-10, and TNF-α).

RESULTS

Exercise reduced the percentage of classical monocytes and increased the percentage of intermediate and nonclassical monocytes. In addition, TLR4 expression decreased on classical and intermediate monocytes, but not the nonclassical monocyte subset. Furthermore, although CD14 expression decreased on all monocyte subsets, CD16 expression increased on intermediate monocytes only. In parallel with these phenotypic changes, the inflammatory milieu shifted toward a proinflammatory response after LPS stimulation (decreased IL-6 and IL-10 and increased IL-6 to IL-10 ratio and TNF-α production).

CONCLUSIONS

These findings demonstrate that acute maximal exercise elicits a proinflammatory phenotype of isolated monocytes exposed to LPS and highlight potential mechanisms that will help elucidate the role of acute and chronic exercise on the innate immune response of circulating monocytes.

Monocyte Subsets in Atherosclerosis and Modification with Exercise in Humans

Atherosclerosis is a progressive pathological remodeling of the arteries and one of its hallmarks is the presence of chronic inflammation. Notably, there is an increased proportion and activation state of specific monocyte subsets in systemic blood circulation. Monocyte subsets have distinct contributions to the formation, progression, and destabilization of the atherosclerotic plaque. Strong clinical and epidemiological studies show that regular aerobic exercise mitigates the progression of cardiovascular disease. In fact, aerobic fitness is a powerful predictor of cardiovascular mortality in adults, independent of traditional risk factors such as hypertension and hyperlipidemia. Acute bouts and chronic exercise training modulate monocyte behavior, ranging from their recruitment from the bone marrow or marginal pool, to tissue margination and functional changes in cytokine and chemokine production. Such modulation could reflect a potential mechanism for the cardio-protective effect of exercise on atherosclerosis. This review summarizes the current knowledge of monocyte subsets and highlights what is known about their responses to exercise.

Peripheral Lymphocytes, Obesity, and Metabolic Syndrome in Young Adults: An Immunometabolism Study

BACKGROUND

Obesity is characterized by a low-intensity chronic inflammatory process in which immune system cells interact in a complex network, which affects systemic metabolic processes. This raises interest in analyzing possible changes in the proportions of immune system cells in individuals with obesity with and without metabolic syndrome (MS), in relation to their body composition.

METHODS

Circulating cells were analyzed with flow cytometry in young adults: monocytes, granulocytes, lymphocytes (T, B, and natural killer [NK]), TCD4⁺CD62^-, TCD8⁺CD28^-, and naive and memory cells of TCD3⁺ and TCD4⁺. Body composition was obtained by bioelectrical impedance analysis and dual-energy X-ray absorptiometry, and metabolic parameters.

RESULTS

A total of 169 persons were evaluated: 20% presented normal body mass index (BMI); 49% was overweight, and 31% had obesity; 28% had MS. It was observed that with an increase in BMI and visceral adipose tissue increase (VATI), body composition and biochemical variables were negatively altered. With regard to cell subpopulations, total lymphocytes increased and granulocytes and NK lymphocytes decreased in patients with MS and VATI. Memory cells increased with BMI and VATI. In individuals with MS, monocytes, and NK lymphocytes comprised a negative association with VAT, fat mass, and skeletal muscle mass (SMM). In individuals with MS and VATI, a negative correlation was observed between monocytes and SMM.

CONCLUSIONS

Significant changes were detected in the subpopulations of lymphocytes, suggesting that weight gain, SMM, and VAT accumulation gave rise to immunological changes at the peripheral level, and the presence of increased memory cells could be related to low-intensity chronic inflammation.

Ten weeks of high-intensity interval walk training is associated with reduced disease activity and improved innate immune function in older adults with rheumatoid arthritis: a pilot study

Background

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which adults have significant joint issues leading to poor health. Poor health is compounded by many factors, including exercise avoidance and increased risk of opportunistic infection. Exercise training can improve the health of patients with RA and potentially improve immune function; however, information on the effects of high-intensity interval training (HIIT) in RA is limited. We sought to determine whether 10 weeks of a walking-based HIIT program would be associated with health improvements as measured by disease activity and aerobic fitness. Further, we assessed whether HIIT was associated with improved immune function, specifically antimicrobial/bacterial functions of neutrophils and monocytes.

Methods

Twelve physically inactive adults aged 64 ± 7 years with either seropositive or radiographically proven (bone erosions) RA completed 10 weeks of high-intensity interval walking. Training consisted of 3 × 30-minute sessions/week of ten ≥ 60-second intervals of high intensity (80–90% VO_2reserve) separated by similar bouts of lower-intensity intervals (50–60% VO_2reserve). Pre- and postintervention assessments included aerobic and physical function; disease activity as measured by Disease Activity score in 28 joints (DAS28), self-perceived health, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR); plasma interleukin (IL)-1β, IL-6, chemokine (C-X-C motif) ligand (CXCL)-8, IL-10, and tumor necrosis factor (TNF)-α concentrations; and neutrophil and monocyte phenotypes and functions.

Results

Despite minimal body composition change, cardiorespiratory fitness increased by 9% (change in both relative and absolute aerobic capacity; p < 0.001), and resting blood pressure and heart rate were both reduced (both p < 0.05). Postintervention disease activity was reduced by 38% (DAS28; p = 0.001) with significant reductions in ESR and swollen joints as well as improved self-perceived health. Neutrophil migration toward CXCL-8 (p = 0.003), phagocytosis of Escherichia coli (p = 0.03), and ROS production (p < 0.001) all increased following training. The frequency of cluster of differentiation 14-positive (CD14⁺)/CD16⁺ monocytes was reduced (p = 0.002), with both nonclassical (CD14^dim/CD16^bright) and intermediate (CD14^bright/CD16^positive) monocytes being reduced (both p < 0.05). Following training, the cell surface expression of intermediate monocyte Toll-like receptor 2 (TLR2), TLR4, and HLA-DR was reduced (all p < 0.05), and monocyte phagocytosis of E. coli increased (p = 0.02). No changes were observed for inflammatory markers IL-1β, IL-6, CXCL-8, IL-10, CRP, or TNF-α.

Conclusions

We report for the first time, to our knowledge, that a high-intensity interval walking protocol in older adults with stable RA is associated with reduced disease activity, improved cardiovascular fitness, and improved innate immune functions, indicative of reduced infection risk and inflammatory potential. Importantly, the exercise program was well tolerated by these patients.

Trial registration

ClinicalTrials.gov, NCT02528344. Registered on 19 August 2015.

Effects of l-arginine supplementation associated with continuous or interval aerobic training on chronic heart failure rats

OBJECTIVE

Chronic heart failure (CHF) is related with exercise intolerance and impaired nitric oxide (NO) production, which can lead to several functional capacity alterations. Considering the possible superiority of aerobic interval training compared to continuous training and the capacity of l-arginine to restore the NO pathway, the aim of the present study was to investigate whether these treatments are beneficial to exercise capacity, muscle mass preservation and hemodynamic, inflammatory and oxidative stress parameters in CHF rats.

METHODS

Thirty-eight male Wistar rats post 6weeks of myocardial infarction (MI) surgery were randomly assigned into 6 CHF groups: sedentary (SED, n=6); SED+Arg (n=7); ACT (n=8); ACT+Arg (n=5); AIT (n=7); AIT+Arg (n=5). Exercise test capacity (ETC) was performed pre and post 8weeks of intervention. Supplemented rats received Arg (1g/kg) by oral gavage (7×/week). Exercise training was performed on a rat treadmill (5×/week). Hemodynamic variables, tissue collection, congestion, inflammatory cytokines, and oxidative parameters were evaluated at the end of protocols.

RESULTS

All trained groups showed a superior exercise capacity compared to SED groups on the post-intervention test (p<0.0001). Pulmonary congestion was attenuated in AIT and AIT+Arg compared with the SED group (p<0.05). Left ventricular end-diastolic pressure (LVEDP) was lower in ACT+Arg, AIT, and AIT+Arg groups than SED group (p<0.05). Association of AIT with Arg supplementation was able to improve hemodynamic responses (left ventricular systolic pressure (LVSP), systolic blood pressure (SBP), +dP/dt_max, and -dP/dt_max (p<0.05), likewise, decrease muscular and renal lipid peroxidation and tumor necrosis factor (TNF)-α, and increase interleukin (IL)-10/TNF-α plasmatic levels (p<0.01). Groups that associated aerobic exercise with Arg supplementation (ACT+Arg and AIT+Arg) revealed higher gastrocnemius mass compared to the SED group (p<0.01).

CONCLUSIONS

Both aerobic training protocols were capable to improve aerobic capacity, and the association with Arg supplementation was important to attenuate muscle loss. Moreover, interval training associated with Arg supplementation elicits greater improvements in hemodynamic parameters, contributing to reduction in pulmonary congestion, and demonstrated particular responses in the inflammatory profile and in the antioxidant status.

Exercise and mental health

There is a growing body of literature that recognizes the positive effects of exercise on mood states such as anxiety, stress and depression, through physiological and biochemical mechanisms, including endorphins, mitochondria, mammalian target of rapamycin, neurotransmitters and the hypothalamic-pituitary-adrenal axis, and via the thermogenic hypothesis. In addition, psychological mechanisms influence the effects of exercise on mood states, as suggested by both the distraction hypothesis and the self-efficacy hypothesis. Exercise has also been shown to reduce inflammation via several different processes (inflammation, cytokines, toll-like receptors, adipose tissue and via the vagal tone), which can contribute to better health outcomes in people suffering from mood disorders.