Habitual physical activity is associated with the maintenance of neutrophil migratory dynamics in healthy older adults

Immunosenescence: Aging and Immune System Decline

Immunosenescence, a systematic reduction in the immune system connected with age, profoundly affects the health and well-being of elderly individuals. This review outlines the hallmark features of immunosenescence, including thymic involution, inflammaging, cellular metabolic adaptations, and hematopoietic changes, and their impact on immune cells such as macrophages, neutrophils, T cells, dendritic cells, B cells, and natural killer (NK) cells. Thymic involution impairs the immune system's capacity to react to novel antigens by reducing thymopoiesis and shifting toward memory T cells. Inflammaging, characterized by chronic systemic inflammation, further impairs immune function. Cellular metabolic adaptations and hematopoietic changes alter immune cell function, contributing to a diminished immune response. Developing ways to reduce immunosenescence and enhance immunological function in the elderly population requires an understanding of these mechanisms.

Effects of immune exhaustion and senescence of innate immunity in autoimmune disorders

Innate immune system activation is crucial in the inflammatory response, but uncontrolled activation can lead to autoimmune diseases. Cellular exhaustion and senescence are two processes that contribute to innate immune tolerance breakdown. Exhausted immune cells are unable to respond adequately to specific antigens or stimuli, while senescent cells have impaired DNA replication and metabolic changes. These processes can impair immune system function and disrupt homeostasis, leading to the emergence of autoimmunity. However, the influence of innate immune exhaustion and senescence on autoimmune disorders is not well understood. This review aims to describe the current findings on the role of innate immune exhaustion and senescence in autoimmunity, focusing on the cellular and molecular changes involved in each process. Specifically, the article explores the markers and pathways associated with immune exhaustion, such as PD-1 and TIM-3, and senescence, including Β-galactosidase (β-GAL), lamin B1, and p16ink4a, and their impact on autoimmune diseases, namely type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and immune-mediated myopathies. Understanding the mechanisms underlying innate immune exhaustion and senescence in autoimmunity may provide insights for the development of novel therapeutic strategies.

Impact of Immunosenescence in Older Kidney Transplant Recipients: Associated Clinical Outcomes and Possible Risk Stratification for Immunosuppression Reduction

The number of older individuals receiving a kidney transplant as replacement therapy has significantly increased in the past decades and this increase is expected to continue. Older patients have a lower rate of acute rejection but an increased incidence of death with a functioning graft. Several factors, including an increased incidence of infections, post-transplant malignancy and cardiovascular comorbidity and mortality, contribute to this increased risk. Notwithstanding, kidney transplantation is still the best form of kidney replacement therapy in all patients with chronic kidney disease, including in older individuals. The best form of immunosuppression and the optimal dose of these medications in older recipients remains a topic of discussion. Pharmacological studies have usually excluded older patients and when included, patients were highly selected and their numbers insignificant to draw a reasonable conclusion. The reduced incidence of acute rejection in older recipients has largely been attributed to immunosenescence. Immunosenescence refers to the aging of the innate and adaptive immunity, accumulating in phenotypic and functional changes. These changes influences the response of the immune system to new challenges. In older individuals, immunosenescence is associated with increased susceptibility to infectious pathogens, a decreased response after vaccinations, increased risk of malignancies and cardiovascular morbidity and mortality. Chronic kidney disease is associated with premature immunosenescent changes, and these are independent of aging. The immunosenescent state is associated with low-grade sterile inflammation termed inflammaging. This chronic low-grade inflammation triggers a compensatory immunosuppressive state to avoid further tissue damage, leaving older individuals with chronic kidney disease in an immune-impaired state before kidney transplantation. Immunosuppression after transplantation may further enhance progression of this immunosenescent state. This review covers the role of immunosenescence in older kidney transplant recipients and it details present knowledge of the changes in chronic kidney disease and after transplantation. The impact of immunosuppression on the progression and complications of an immunosenescent state are discussed, and the future direction of a possible clinical implementation of immunosenescence to individualize/reduce immunosuppression in older recipients is laid out.

Immunomodulatory effects of exercise in cancer prevention and adjuvant therapy: a narrative review

Successful application of cancer immunotherapy has rekindled hope in cancer patients. However, a number of patients are unresponsive to immunotherapy and related treatments. This unresponsiveness in cancer patients toward different treatment regimens can be mainly attributed to severe immune dysfunction in such patients. Several reports indicate that physical exercise can significantly lead to improved cancer patient outcomes. Since exercise gets immense response from the immune system, it can be utilized to improve immune function. Leukocytes with enhanced functions are substantially mobilized into the circulation by a single bout of intense physical exercise. Chronic physical exercise results in greater muscle endurance and strength and improved cardiorespiratory function. This exercise regime is also useful in improving T-cell abundance and reducing dysfunctional T cells. The current available data strongly justify for future clinical trials to investigate physical exercise use as an adjuvant in cancer therapy; however, optimal parameters using exercise for a defined outcome are yet to be established. The components of the immune system associate with almost every tumorigenesis step. The inter-relationship between inflammation, cancer, and innate immunity has recently gained acceptance; however, the underlying cellular and molecular mechanisms behind this relationship are yet to be solved. Several studies suggest physical exercise-mediated induction of immune cells to elicit anti-tumorigenic effects. This indicates the potential of exercising in modulating the behavior of immune cells to inhibit tumor progression. However, further mechanistic details behind physical exercise-driven immunomodulation and anticancer effects have to be determined. This review aims to summarize and discuss the association between physical exercise and immune function modulation and the potential of exercise as an adjuvant therapy in cancer prevention and treatment.

Natural killer cells immunosenescence and the impact of lifestyle management

Natural killer cells (NKs) are lymphocytes of the innate immune system that quickly respond to viruses, infections, and tumors during their short cell life cycle. However, it was recently found that NKs undergo quantitative, distributional, structural, and functional phenotypic changes during aging that suppress immune responses, which is known as immunosenescence. The aging host environment, cytokine regulation, cytomegalovirus status, and hypothalamic‒pituitary‒adrenal axis have significant effects on NK function. Different lifestyle management interventions modulate the number and cytotoxic activity of NKs, which are essential for rebuilding the immune barrier against pathogens in elderly individuals. Based on recent studies, we review the phenotypic changes of and potential threats of NKs during aging and explore the underlying mechanisms. By summarizing the effects of lifestyle management on NKs and their application prospects, we aim to provide evidence for enhancing immune system function against immune diseases in elderly individuals.

Multi-omics approaches in psychoneuroimmunology and health research: Conceptual considerations and methodological recommendations

The field of psychoneuroimmunology (PNI) has grown substantially in both relevance and prominence over the past 40 years. Notwithstanding its impressive trajectory, a majority of PNI studies are still based on a relatively small number of analytes. To advance this work, we suggest that PNI, and health research in general, can benefit greatly from adopting a multi-omics approach, which involves integrating data across multiple biological levels (e.g., the genome, proteome, transcriptome, metabolome, lipidome, and microbiome/metagenome) to more comprehensively profile biological functions and relate these profiles to clinical and behavioral outcomes. To assist investigators in this endeavor, we provide an overview of multi-omics research, highlight recent landmark multi-omics studies investigating human health and disease risk, and discuss how multi-omics can be applied to better elucidate links between psychological, nervous system, and immune system activity. In doing so, we describe how to design high-quality multi-omics studies, decide which biological samples (e.g., blood, stool, urine, saliva, solid tissue) are most relevant, incorporate behavioral and wearable sensing data into multi-omics research, and understand key data quality, integration, analysis, and interpretation issues. PNI researchers are addressing some of the most interesting and important questions at the intersection of psychology, neuroscience, and immunology. Applying a multi-omics approach to this work will greatly expand the horizon of what is possible in PNI and has the potential to revolutionize our understanding of mind-body medicine.

Influence of age and fitness level on immune responses of T and NK cells in healthy physically active subjects after strenuous aerobic exercise: a cross-sectional study

Aim

The aim of this study is to analyze whether immune responses after strenuous exercise are influenced by chronological age and fitness level in physically active healthy men.

Methods

Cross-sectional study with a sample of 32 physically active men. Participants were divided into two groups based on chronological age (younger: age 21.8 ± 1.8 vs. older: age 34.6 ± 8.3) and subsequently regrouped and divided based on fitness level (More conditioned: excellent and superior VO2max vs. Less conditioned: VO2max: weak, regular and good). Fitness was classified according to VO2max levels obtained by a treadmill test using a gas analyzer. Before and immediately after the ergospirometry test, blood samples were collected for evaluation of immunological markers: leukocytes, neutrophils, lymphocytes and subpopulations.

Results

Chronological age had a moderate effect on CD3+CD4+ lymphocyte count (effect size: 0.204) and CD4/CD8 ratio (effect size: 0.278), favoring older subjects. The level of physical fitness had no significant effect on the analyzed immunological markers.

Conclusions

Immune responses observed immediately after strenuous exercise may be more dependent on chronological age than on fitness level in healthy, physically active men.

Mechanisms underlying the beneficial effects of physical exercise on multiple sclerosis: focus on immune cells

Multiple sclerosis (MS) is a prevalent neuroimmunological illness that leads to neurological disability in young adults. Although the etiology of MS is heterogeneous, it is well established that aberrant activity of adaptive and innate immune cells plays a crucial role in its pathogenesis. Several immune cell abnormalities have been described in MS and its animal models, including T lymphocytes, B lymphocytes, dendritic cells, neutrophils, microglia/macrophages, and astrocytes, among others. Physical exercise offers a valuable alternative or adjunctive disease-modifying therapy for MS. A growing body of evidence indicates that exercise may reduce the autoimmune responses triggered by immune cells in MS. This is partially accomplished by restricting the infiltration of peripheral immune cells into the central nervous system (CNS) parenchyma, curbing hyperactivation of immune cells, and facilitating a transition in the balance of immune cells from a pro-inflammatory to an anti-inflammatory state. This review provides a succinct overview of the correlation between physical exercise, immune cells, and MS pathology, and highlights the potential benefits of exercise as a strategy for the prevention and treatment of MS.

Diagnostics of inflammaging in relation to sarcopenia

One of the theories about aging focuses on the immune response and relates to the activation of subclinical and chronic inflammation. This study was designed to investigate the relationship between inflammation and sarcopenia and to evaluate the influence of lifestyle on the inflammatory profile. Finally, therapeutic strategies to counteract the pathophysiological effect of skeletal muscle aging were also indicated. One hundred seventy-three individuals aged 71.5 ± 6.8 years were divided into two groups: sarcopenia and probable sarcopenia (n = 39) and no sarcopenia (n = 134). Sarcopenia was assessed according to the algorithm of the European Working Group on Sarcopenia in the older adults 2. C-reactive protein (CRP) (p = 0.011) and CRP/albumin ratio (p = 0.030) as well as IL-1β (p = 0.002), cfDNA (p < 0.001) and bilirubin levels (p = 0.002) were significantly higher in the sarcopenia group as opposed to the no sarcopenia group. No significant differences were observed between groups in the concentration of TNFα (p = 0.429) and IL-6 (p = 0.300). An inverse correlation was found between gait speed and cfDNA (r_s = -0.234, p < 0.01) and IL-1β (r_s = -0.263, p < 0.01). The ROC analysis of cfDNA, CRP, IL-1β and bilirubin ranged from 0.6 to 0.7, which confirms the association between sarcopenia and inflammatory mediators and indicates high clinical usefulness of cfDNA and bilirubin in sarcopenia prediction. We also indicated a link between inflammation and fitness level in the older adult thereby providing evidence that lifestyle exercise should be a key therapeutic strategy in sarcopenia prevention.

Exercise suppresses neuroinflammation for alleviating Alzheimer's disease

Alzheimer's disease (AD) is a chronic neurodegenerative disease, with the characteristics of neurofibrillary tangle (NFT) and senile plaque (SP) formation. Although great progresses have been made in clinical trials based on relevant hypotheses, these studies are also accompanied by the emergence of toxic and side effects, and it is an urgent task to explore the underlying mechanisms for the benefits to prevent and treat AD. Herein, based on animal experiments and a few clinical trials, neuroinflammation in AD is characterized by long-term activation of pro-inflammatory microglia and the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes. Damaged signals from the periphery and within the brain continuously activate microglia, thus resulting in a constant source of inflammatory responses. The long-term chronic inflammatory response also exacerbates endoplasmic reticulum oxidative stress in microglia, which triggers microglia-dependent immune responses, ultimately leading to the occurrence and deterioration of AD. In this review, we systematically summarized and sorted out that exercise ameliorates AD by directly and indirectly regulating immune response of the central nervous system and promoting hippocampal neurogenesis to provide a new direction for exploring the neuroinflammation activity in AD.

The Impact of Exercise on Immunity, Metabolism, and Atherosclerosis

Physical exercise represents an effective preventive and therapeutic strategy beneficially modifying the course of multiple diseases. The protective mechanisms of exercise are manifold; primarily, they are elicited by alterations in metabolic and inflammatory pathways. Exercise intensity and duration strongly influence the provoked response. This narrative review aims to provide comprehensive up-to-date insights into the beneficial effects of physical exercise by illustrating the impact of moderate and vigorous exercise on innate and adaptive immunity. Specifically, we describe qualitative and quantitative changes in different leukocyte subsets while distinguishing between acute and chronic exercise effects. Further, we elaborate on how exercise modifies the progression of atherosclerosis, the leading cause of death worldwide, representing a prime example of a disease triggered by metabolic and inflammatory pathways. Here, we describe how exercise counteracts causal contributors and thereby improves outcomes. In addition, we identify gaps that still need to be addressed in the future.

Exercise sustains the hallmarks of health

Exercise has long been known for its active role in improving physical fitness and sustaining health. Regular moderate-intensity exercise improves all aspects of human health and is widely accepted as a preventative and therapeutic strategy for various diseases. It is well-documented that exercise maintains and restores homeostasis at the organismal, tissue, cellular, and molecular levels to stimulate positive physiological adaptations that consequently protect against various pathological conditions. Here we mainly summarize how moderate-intensity exercise affects the major hallmarks of health, including the integrity of barriers, containment of local perturbations, recycling and turnover, integration of circuitries, rhythmic oscillations, homeostatic resilience, hormetic regulation, as well as repair and regeneration. Furthermore, we summarize the current understanding of the mechanisms responsible for beneficial adaptations in response to exercise. This review aimed at providing a comprehensive summary of the vital biological mechanisms through which moderate-intensity exercise maintains health and opens a window for its application in other health interventions. We hope that continuing investigation in this field will further increase our understanding of the processes involved in the positive role of moderate-intensity exercise and thus get us closer to the identification of new therapeutics that improve quality of life.

Immunosenescence in Childhood Cancer Survivors and in Elderly: A Comparison and Implication for Risk Stratification

The population of childhood cancer survivors (CCS) has grown rapidly in recent decades. Although cured of their original malignancy, these individuals are at increased risk of serious late effects, including age-associated complications. An impaired immune system has been linked to the emergence of these conditions in the elderly and CCS, likely due to senescent immune cell phenotypes accompanied by low-grade inflammation, which in the elderly is known as "inflammaging." Whether these observations in the elderly and CCS are underpinned by similar mechanisms is unclear. If so, existing knowledge on immunosenescent phenotypes and inflammaging might potentially serve to benefit CCS. We summarize recent findings on the immune changes in CCS and the elderly, and highlight the similarities and identify areas for future research. Improving our understanding of the underlying mechanisms and immunosenescent markers of accelerated immune aging might help us to identify individuals at increased risk of serious health complications.

Salutary effects of moderate but not high intensity aerobic exercise training on the frequency of peripheral T-cells associated with immunosenescence in older women at high risk of breast cancer: a randomized controlled trial

Background

Immunosenescence is described as age-associated changes within the immune system that are responsible for decreased immunity and increased cancer risk. Physically active individuals have fewer ‘senescent’ and more naïve T-cells compared to their sedentary counterparts, but it is not known if exercise training can rejuvenate ‘older looking’ T-cell profiles. We determined the effects of 12-weeks supervised exercise training on the frequency of T-cell subtypes in peripheral blood and their relationships with circulating levels of the muscle-derived cytokines (i.e. ‘myokines’) IL-6, IL-7, IL-15 and osteonectin in older women at high risk of breast cancer. The intervention involved 3 sessions/week of either high intensity interval exercise (HIIT) or moderate intensity continuous exercise (MICT) and were compared to an untrained control (UC) group.

Results

HIIT decreased total granulocytes, CD4+ T-cells, CD4+ naïve T-cells, CD4+ recent thymic emigrants (RTE) and the CD4:CD8 ratio after training, whereas MICT increased total lymphocytes and CD8 effector memory (EM) T-cells. The change in total T-cells, CD4+ naïve T-cells, CD4+ central memory (CM) T-cells and CD4+ RTE was elevated after MICT compared to HIIT. Changes in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{\mathrm{V}}{\mathrm{O}}_{2\max } $$\end{document}V˙O2max after training, regardless of exercise prescription, was inversely related to the change in highly differentiated CD8+ EMRA T-cells and positively related to changes in β2-adrenergic receptor (β2-AR) expression on CM CD4+ and CM CD8+ T-cells. Plasma myokine levels did not change significantly among the groups after training, but individual changes in IL-7 were positively related to changes in the number of β2-AR expressing CD4 naïve T cells in both exercise groups but not controls. Further, CD4 T-cells and CD4 naive T-cells were negatively related to changes in IL-6 and osteonectin after HIIT but not MICT, whereas CD8 EMRA T-cells were inversely related to changes in IL-15 after MICT but not HIIT.

Conclusions

Aerobic exercise training alters the frequency of peripheral T-cells associated with immunosenescence in middle aged/older women at high risk of breast cancer, with HIIT (pro-senescent) and MICT (anti-senescent) evoking divergent effects. Identifying the underlying mechanisms and establishing whether exercise-induced changes in peripheral T-cell numbers can alter the risk of developing breast cancer warrants investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12979-022-00266-z.

Protective Effects of Exercise Become Especially Important for the Aging Immune System in The Covid-19 Era

Aging is a complex, multietiological process and a major risk factor for most non-genetic, chronic diseases including geriatric syndromes that negatively affect healthspan and longevity. In the scenario of "healthy or good aging", especially during the COVID-19 era, the proper implementation of exercise as "adjuvant" or "polypill" to improve disease-related symptoms and comorbidities in the general population is a top priority. However, there is still a gap concerning studies analyzing influence of exercise training to immune system in older people. Therefore, the aim of this review is to provide a brief summary of well-established findings in exercise immunology and immunogerontology, but with a focus on the main exercise-induced mechanisms associated with aging of the immune system (immunosenescence). The scientific data strongly supports the notion that regular exercise as a low-cost and non-pharmacological treatment approach, when adjusted on an individual basis in elderly, induce multiple rejuvenating mechanisms: (1) affects the telomere-length dynamics (a "telo-protective" effect), (2) promote short- and long-term anti-inflammatory effects (via e.g., triggering the anti-inflammatory phenotype), 3) stimulates the adaptive immune system (e.g., helps to offset diminished adaptive responses) and in parallel inhibits the accelerated immunosenescence process, (4) increases post-vaccination immune responses, and (5) possibly extends both healthspan and lifespan.

The Effects of 16 Weeks of Exercise Training on Neutrophil Functions in Breast Cancer Survivors

Following therapy, breast cancer survivors (BCS) have an increased risk of infections because of age and cancer dysregulation of inflammation and neutrophil functions. Neutrophil functions may be improved by exercise training, although limited data exist on exercise and neutrophil functions in BCS.Sixteen BCS [mean age: 56 (SD 11) years old] completed 16 weeks of community-based exercise training and a 45-minute acute bout of cycling before (Base) and after (Final) the exercise training program. Exercise training consisted of 3 x 40 – 60 minute mixed mode aerobic exercises, comprising 10 – 30 minutes aerobic and 30 minutes resistance training. At Base and Final, we took BCS blood samples before (PRE), immediately after (POST), and 1 hour after (1Hr) acute exercise to determine neutrophil counts, phenotype, bacterial killing, IL-6, and IL-8 levels. Eleven healthy, age- and physical activity levels-matched women (Control) completed the acute bout of exercise once as a healthy response reference. Resting Responses. BCS and Controls had similar Base PRE absolute neutrophil counts [mean (SD): 3.3 (1.9) v 3.1 (1.2) x 10⁹/L, p=0.801], but BCS had lower bacterial phagocytosis [3991 (1233) v 4881 (417) MFI, p=0.035] and higher oxidative killing [6254 (1434) v 4709 (1220) MFI, p=0.005], lower CD16 [4159 (1785) v 7018 (1240) MFI, p<0.001], lower CXCR2 [4878 (1796) v 6330 (1299) MFI, p=0.032] and higher TLR2 [98 (32) v 72 (17) MFI, p=0.022] expression, while IL-6 [7.4 (5.4) v 4.0 (2.7) pg/mL, p=0.079] levels were marginally higher and IL-8 [6.0 (4.7) v 7.9 (5.0) pg/mL, p=0.316] levels similar. After 16 weeks of training, compared to Controls, BCS Final PRE phagocytosis [4510 (738) v 4881 (417) MFI, p=0.146] and TLR2 expression [114 (92) v 72 (17) MFI, p=0.148] were no longer different. Acute Exercise Responses. As compared to Controls, at Base, BCS phagocytic Pre-Post response was lower [mean difference, % (SD): 12% (26%), p=0.042], CD16 Pre-Post response was lower [12% (21%), p=0.016] while CD16 Pre-1Hr response was higher [13% (25%), p=0.022], TLR2 Pre-Post response was higher [15% (4%) p=0.002], while IL-8 Pre-Post response was higher [99% (48%), p=0.049]. As compared to Controls, following 16 weeks of training BCS phagocytic Pre-Post response [5% (5%), p=0.418], CD16 Pre-1Hr response [7% (7%), p=0.294], TLR2 Pre-Post response [6% (4%), p=0.092], and IL-8 Pre-Post response [1% (9%), p=0.087] were no longer different. Following cancer therapy, BCS may have impaired neutrophil functions in response to an acute bout of exercise that are partially restored by 16 weeks of exercise training. The improved phagocytosis of bacteria in BCS may represent an exercise-induced intrinsic improvement in neutrophil functions consistent with a reduced risk of infectious disease.

The Association of Anti-Inflammatory Diet Ingredients and Lifestyle Exercise with Inflammaging

One of the latest theories on ageing focuses on immune response, and considers the activation of subclinical and chronic inflammation. The study was designed to explain whether anti-inflammatory diet and lifestyle exercise affect an inflammatory profile in the Polish elderly population. Sixty individuals (80.2 ± 7.9 years) were allocated to a low-grade inflammation (LGI n = 33) or high-grade inflammation (HGI n = 27) group, based on C-reactive protein concentration (<3 or ≥3 mg/L) as a conventional marker of systemic inflammation. Diet analysis focused on vitamins D, C, E, A, β-carotene, n-3 and n-6 PUFA using single 24-h dietary recall. LGI demonstrated a lower n-6/n-3 PUFA but higher vitamin D intake than HGI. Physical performance based on 6-min walk test (6MWT) classified the elderly as physically inactive, whereby LGI demonstrated a significantly higher gait speed (1.09 ± 0.26 m/s) than HGI (0.72 ± 0.28 m/s). Circulating interleukins IL-1β, IL-6, IL-13, TNFα and cfDNA demonstrated high concentrations in the elderly with low 6MWT, confirming an impairment of physical performance by persistent systemic inflammation. These findings reveal that increased intake of anti-inflammatory diet ingredients and physical activity sustained throughout life attenuate progression of inflammaging in the elderly and indicate potential therapeutic strategies to counteract pathophysiological effects of ageing.

B Cell Immunosenescence

Innate and adaptive immune responses decline with age, leading to greater susceptibility to infectious diseases and reduced responses to vaccines. Diseases are more severe in old than in young individuals and have a greater impact on health outcomes such as morbidity, disability, and mortality. Aging is characterized by increased low-grade chronic inflammation, so-called inflammaging, that represents a link between changes in immune cells and a number of diseases and syndromes typical of old age. In this review we summarize current knowledge on age-associated changes in immune cells with special emphasis on B cells, which are more inflammatory and less responsive to infections and vaccines in the elderly. We highlight recent findings on factors and pathways contributing to inflammaging and how these lead to dysfunctional immune responses. We summarize recent published studies showing that adipose tissue, which increases in size with aging, contributes to inflammaging and dysregulated B cell function.

The Effects of Lifestyle and Diet on Gut Microbiota Composition, Inflammation and Muscle Performance in Our Aging Society

Living longer is associated with an increased risk of chronic diseases, including impairments of the musculoskeletal and immune system as well as metabolic disorders and certain cancers, each of which can negatively affect the relationship between host and microbiota up to the occurrence of dysbiosis. On the other hand, lifestyle factors, including regular physical exercise and a healthy diet, can affect skeletal muscle and immune aging positively at all ages. Accordingly, health benefits could partly depend on the effect of such interventions that influence the biodiversity and functionality of intestinal microbiota. In the present review, we first discuss the physiological effects of aging on the gut microbiota, immune system, and skeletal muscle. Secondly, we describe human epidemiological evidence about the associations between physical activity and fitness and the gut microbiota composition in older adults. The third part highlights the relevance and restorative mechanisms of immune protection through physical activity and specific exercise interventions during aging. Fourth, we present important research findings on the effects of exercise and protein as well as other nutrients on skeletal muscle performance in older adults. Finally, we provide nutritional recommendations to prevent malnutrition and support healthy active aging with a focus on gut microbiota. Key nutrition-related concerns include the need for adequate energy and protein intake for preventing low muscle mass and a higher demand for specific nutrients (e.g., dietary fiber, polyphenols and polyunsaturated fatty acids) that can modify the composition, diversity, and metabolic capacity of the gut microbiota, and may thus provide a practical means of enhancing gut and systemic immune function.

Impact of exercise on the immune system and outcomes in hematologic malignancies

Exercise is increasingly recognized as important to cancer care. The biology of how exercise improves outcomes is not well understood, however. Studies show that exercise favorably influences the immune system in healthy individuals (neutrophils, monocytes, natural killer cells, T cells, and a number of cytokines). Thus, exercise in patients with hematologic cancer could significantly improve immune function and tumor microenvironment. We performed a literature search and identified 7 studies examining exercise and the immune environment in hematologic malignancies. This review focuses on the role of exercise and physical activity on the immune system in hematologic malignancies and healthy adults.

Age and frailty are independently associated with increased COVID-19 mortality and increased care needs in survivors: results of an international multi-centre study

INTRODUCTION

Increased mortality has been demonstrated in older adults with coronavirus disease 2019 (COVID-19), but the effect of frailty has been unclear.

METHODS

This multi-centre cohort study involved patients aged 18 years and older hospitalised with COVID-19, using routinely collected data. We used Cox regression analysis to assess the impact of age, frailty and delirium on the risk of inpatient mortality, adjusting for sex, illness severity, inflammation and co-morbidities. We used ordinal logistic regression analysis to assess the impact of age, Clinical Frailty Scale (CFS) and delirium on risk of increased care requirements on discharge, adjusting for the same variables.

RESULTS

Data from 5,711 patients from 55 hospitals in 12 countries were included (median age 74, interquartile range [IQR] 54-83; 55.2% male). The risk of death increased independently with increasing age (>80 versus 18-49: hazard ratio [HR] 3.57, confidence interval [CI] 2.54-5.02), frailty (CFS 8 versus 1-3: HR 3.03, CI 2.29-4.00) inflammation, renal disease, cardiovascular disease and cancer, but not delirium. Age, frailty (CFS 7 versus 1-3: odds ratio 7.00, CI 5.27-9.32), delirium, dementia and mental health diagnoses were all associated with increased risk of higher care needs on discharge. The likelihood of adverse outcomes increased across all grades of CFS from 4 to 9.

CONCLUSION

Age and frailty are independently associated with adverse outcomes in COVID-19. Risk of increased care needs was also increased in survivors of COVID-19 with frailty or older age.

Lifestyle exercise attenuates immunosenescence; flow cytometry analysis

Background

Interaction of physical activity and overall immune profile is very complex and depends on the intensity, duration and frequency of undertaken physical activity, the exposure to cytomegalovirus (CMV) infection and the age-related changes in the immune system. Daily physical activity, which particularly influences immunity, declines dramatically with age. Therefore, the aim of the study was to explain whether physical activity sustained throughout life can attenuate or reverse immunosenescence.

Methods

Ninety-nine older adults (60–90 years) were recruited for the study. According to the 6-min walk test (6WMT), the Åstrand-Ryhming bike test (VO₂max) and Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire, the individuals were classified as physically active (n = 34) and inactive (n = 20) groups. The analysis of T lymphocytes between active vs. inactive participants was performed using eight-parameter flow cytometry.

Results

Analysis of the baseline peripheral naïve and memory T lymphocytes showed a significant relationship of lifestyle exercise with the CD4/CD8 ratio. Above 50% of physically active participants demonstrated the CD4/CD8 ratio ≥ 1 or ≤ 2.5 contrary to the inactive group who showed the ratio < 1. The older adults with the result of 6WMT > 1.3 m/s and VO₂max > 35 mL/kg/min had a significantly higher CD4⁺CD45RA⁺ T lymphocyte percentage and also a higher ratio of CD4⁺CD45RA⁺/CD4⁺CD45RO⁺. Interestingly, in active older adults with IgG CMV⁺ (n = 30) the count of CD4⁺CD45RA⁺ T lymphocytes was higher than in the inactive group with IgG CMV⁺ (n = 20).

Conclusion

Based on the flow cytometry analysis, we concluded that lifestyle exercise could lead to rejuvenation of the immune system by increasing the percentage of naïve T lymphocytes or by reducing the tendency of the inverse CD4/CD8 ratio.

Frailty Is Associated With Neutrophil Dysfunction Which Is Correctable With Phosphoinositol-3-Kinase Inhibitors

Neutrophil dysfunction has been described with age, appears exaggerated in infection, with altered phosphoinositol signaling a potential mechanism. However, functional aging is heterogeneous. Frailty is a negative health status and is more common in older adults. We hypothesized that neutrophil migration may be compromised in frailty, associated with the degree of frailty experienced by the older person. We compared measures of frailty, neutrophil function, and systemic inflammation in 40 young and 77 older community-dwelling adults in the United Kingdom. Systemic neutrophils exhibited an age-associated reduction in the accuracy of migration (chemotaxis) which was further blunted with frailty. The degree of migratory inaccuracy correlated with physical (adjusted hand grip strength) and cognitive (Stroop test) markers of frailty. Regression analysis demonstrated that age, Charlson comorbidity index, and frailty index were able to predict neutrophil chemotaxis. Reduced chemotaxis of neutrophils from frail adults could be reversed using selective PI3K inhibitors. Exposure of neutrophils from young adults to plasma from chronically inflamed frail older adults could not recapitulate the migratory deficit in vitro, and there were no relationships with systemic inflammation and neutrophil dysfunction. Frailty exaggerated the neutrophil deficits seen with advanced age but aspects of the frailty-associated deficit in neutrophil function are rescuable and thus potentially form a therapeutic target to improve outcomes from infection in older adults.

Benefits and promotion of physical activity in rheumatoid arthritis

PURPOSE OF REVIEW

The aim of this article is to describe the benefits of physical activity and exercise on rheumatoid arthritis disease activity, functioning, and symptoms; and offer recommendations for promotion of physical activity and exercise among people with rheumatoid arthritis.

RECENT FINDINGS

In addition to well-known benefits of exercise such as improving cardiovascular health and metabolic syndrome and reducing obesity, exercise has consistently shown rheumatoid arthritis-specific benefits. Exercise and increases in physical activity improve clinically measured disease activity, reduce symptoms such as fatigue and pain, and improve function and mental health. In spite of these benefits, most people with rheumatoid arthritis are inactive. Patient barriers to engaging in physical activity may include fears of joint damage, rheumatoid arthritis symptoms, and lack of understanding that physical activity improves the symptoms that may be barriers. However, the greatest barrier to healthy levels of physical activity among individuals with rheumatoid arthritis appears to be the lack of direction from healthcare providers.

SUMMARY

Exercise is safe and highly beneficial for people with rheumatoid arthritis. Because receiving recommendations from healthcare providers may be the factor most strongly associated with engaging in physical activity or exercise, providers are encouraged to give patients positive messages about the benefits of physical activity and the extremely low risks of harm.

Neutrophil Modulation in Alpha-1 Antitrypsin Deficiency

Neutrophils have been implicated in the pathogenesis of alpha-1 antitrypsin deficiency (AATD) since the first descriptions of the disease. Neutrophil proteinases can cause all lung manifestations of AATD, from small airways destruction, to emphysema, to chronic bronchitis and airflow obstruction. Initially, it was proposed that neutrophil functions were normal in AATD, responding in an initially physiological manner to a high burden of pulmonary inflammation. More recent studies have shed new light on this, describing changes in neutrophil responses (a modulation of usual cellular functions) in the presence of inflammation or infection which might enhance tissue damage while impeding bacterial clearance, providing some evidence to support there being an AATD neutrophil phenotype. Many facets of neutrophil function in AATD can be explained by the loss of alpha-1 antitrypsin (AAT) in diverse biological processes. If this were the only reason for altered neutrophil functions, one would predict similar disease presentation across affected people. However, this is not the case. Despite similar (low) levels of AAT, lung disease is extremely variable in AATD, with some patients suffering a significant burden of lung disease and some much less, irrespective of smoking habits and, in some cases, despite augmentation therapy. This review will explore how complex neutrophil responses are and how they are altered with age, inflammation and AATD. Further, it will discuss the need to understand more completely which aspects of AATD-associated disease are driven by neutrophils and how patients more susceptible to neutrophil dysfunction could be identified to potentially stratify treatment approaches.

Creatine supplementation does not promote additional effects on inflammation and insulin resistance in older adults: A pilot randomized, double-blind, placebo-controlled trial

BACKGROUND

A chronic, low-grade inflammation is commonly present in older adults and has been associated with the onset of age-related chronic diseases. Resistance training (RT) and creatine (CR) supplementation emerged as promising strategies to reduce circulating pro-inflammatory cytokines. This study aimed to investigate the effects of CR supplementation combined with RT on markers of inflammation and insulin resistance in community-dwelling older adults.

METHODS

In a pilot randomized, double-blind, placebo-controlled trial, participants were allocated to one of the following groups: 1) Creatine supplementation and resistance training (CR + RT, n = 13); 2) Placebo and resistance training (PL + RT, n = 14). While engaged in a 12-week RT program, participants from CR + RT group received 5 g/day of CR monohydrate and participants from PL + RT group received the same dose of maltodextrin. At baseline and at week 12, blood samples were collected for glucose, insulin, adiponectin, leptin, interleukin 6, interleukin 10, monocyte chemo-attractant protein-1 and C-reactive protein analysis.

RESULTS

After 12 weeks of intervention, there were no differences between groups in any of the variables analyzed. Monocyte chemoattractant protein-1 was reduced in both groups (CR + RT: -55.66 ± 48.93 pg/mL, p < 0.01, dz = 1.13; PL + RT: -46.52 ± 55.21 pg/mL, p < 0.01, dz = 0.84).

CONCLUSION

Resistance training, regardless of CR supplementation, decreased MCP-1 concentration in older adults.

Rejuvenation of Neutrophil Functions in Association With Reduced Diabetes Risk Following Ten Weeks of Low-Volume High Intensity Interval Walking in Older Adults With Prediabetes - A Pilot Study

Neutrophil dysfunction is a common feature of aging, and is associated with the pathogenesis of many age-related diseases, including type 2 diabetes mellitus (T2DM). Although exercise training improves metabolic health, decreases risk of T2DM, and is associated with improving neutrophil functions, involvement in regular physical activity declines with age. The aim of this study was to determine if neutrophil functions could be improved in association with changes in fitness and metabolic parameters in older adults at risk for T2DM using 10-weeks of low volume high-intensity interval exercise training (HIIT). Ten older (71 ± 5 years) sedentary adults with prediabetes (HbA1c: 6.1 ± 0.3%) completed 10 weeks of a supervised HIIT program. Three 30 min sessions/week consisted of ten 60 s intervals of low intensity [50-60% heart rate reserve (HRR)] separated with similar durations of high intensity intervals (80-90% HRR). Before and after training, glucose and insulin sensitivity, neutrophil chemotaxis, bacterial phagocytosis, reactive oxygen species (ROS) production, and mitochondrial functions were assessed. Exercise-mediated changes in cardiorespiratory fitness (VO2peak) and neutrophil functions were compared to six young (23 ± 1 years) healthy adults. Following training, significant reductions in fasting glucose and insulin were accompanied by improved glucose control and insulin sensitivity (all p < 0.05). Before exercise training, VO2peak in the old participants was significantly less than that of the young controls (p < 0.001), but increased by 16 ± 11% following training (p = 0.002) resulting in a 6% improvement of the deficit. Neutrophil chemotaxis, phagocytosis and stimulated ROS production were significantly less than that of the young controls, while basal ROS were higher before training (all p < 0.05). Following training, chemotaxis, phagocytosis and stimulated ROS increased while basal ROS decreased, similar to levels observed in the young controls (all p < 0.05) and reducing the deficit of the young controls between 2 and 154%. In five of the adults with prediabetes, neutrophil mitochondrial functions were significantly poorer than the six young controls before training. Following training, mitochondrial functions improved toward those observed in young controls (all p < 0.05), reducing the deficit of the young controls between 14.3 and 451%. Ten weeks of HIIT in older adults at risk for T2DM reduced disease risk accompanied by improved primary and bioenergetic neutrophil functions. Our results are consistent with a reduced risk of infections mediated by relationships in exercise induced systemic and cellular metabolic features. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT02441205, registered on May 12th, 2015.

Physical Activity and Diet Shape the Immune System during Aging

With increasing age, the immune system undergoes a remodeling process, termed immunosenescence, which is accompanied by considerable shifts in leukocyte subpopulations and a decline in various immune cell functions. Clinically, immunosenescence is characterized by increased susceptibility to infections, a more frequent reactivation of latent viruses, decreased vaccine efficacy, and an increased prevalence of autoimmunity and cancer. Physiologically, the immune system has some adaptive strategies to cope with aging, while in some settings, maladaptive responses aggravate the speed of aging and morbidity. While a lack of physical activity, decreased muscle mass, and poor nutritional status facilitate immunosenescence and inflammaging, lifestyle factors such as exercise and dietary habits affect immune aging positively. This review will discuss the relevance and mechanisms of immunoprotection through physical activity and specific exercise interventions. In the second part, we will focus on the effect of dietary interventions through the supplementation of the essential amino acid tryptophan, n-3 polyunsaturated fatty acids, and probiotics (with a special focus on the kynurenine pathway).

Role of neutrophils in ischemic heart failure

Amplified innate leukocytes (neutrophils and monocytes/macrophages) are associated with advanced ischemic and non-ischemic heart failure (HF). Intensified neutrophilic leukocytosis (neutrophilia) and sustained activation of neutrophils is the predominant factor that determines over activated inflammation in acute HF and the outcome of long-term chronic HF. After heart attack, the first wave of innate responsive and short-lived neutrophils is essential for the initiation of inflammation, resolution of inflammation, and cardiac repair, however uncontrolled and long-term activation of neutrophils leads to collateral damage of myocardium. In the presented review, we highlighted the interactive and integrative role of neutrophil phenotypes in cellular and molecular events of ischemic HF. In addition, we discussed the current, nonimmune, immune, and novel paradigms of neutrophils in HF associated with differential factors with a specific interest in non-resolving inflammation and resolution physiology.

Consumption of an Anthocyanin-Rich Extract Made From New Zealand Blackcurrants Prior to Exercise May Assist Recovery From Oxidative Stress and Maintains Circulating Neutrophil Function: A Pilot Study

Aim: To evaluate blackcurrant anthocyanin-rich extract (BAE) consumption on time- and dose-dependent plasma anthocyanin bioavailability and conduct a pilot study to explore the potential effect of BAE in promoting recovery from exercise-induced oxidative stress, and maintenance of circulating neutrophil function.

Methods: Time- and dose-dependent blackcurrant anthocyanin bioavailability was assessed using LC-MS in 12 participants over 6 h after the ingestion of a placebo or BAE containing 0.8, 1.6, or 3.2 mg/kg total anthocyanins. In a separate pilot intervention exercise trial, 32 participants consumed either a placebo or 0.8, 1.6, or 3.2 mg/kg BAE (8 individuals per group), and then 1 h later performed a 30 min row at 70% VO₂max. Blood was collected during the trial for oxidative, antioxidant, inflammatory, and circulating neutrophil status.

Results: Consumption of BAE caused a time- and dose-dependent increase in plasma anthocyanins, peaking at 2 h after ingestion of 3.2 mg/kg BAE (217 ± 69 nM). BAE consumed 1 h prior to a 30 min row had no effect on plasma antioxidant status but hastened the recovery from exercise-induced oxidative stress: By 2 h recovery, consumption of 1.6 mg/kg BAE prior to exercise caused a significant (P < 0.05) 34 and 32% decrease in post-exercise plasma oxidative capacity and protein carbonyl levels, respectively, compared to placebo. BAE consumption prior to exercise dose-dependently attenuated a small, yet significant (P < 0.01) transient 13 ± 2% decline in circulating neutrophils observed in the placebo group immediately post-exercise. Furthermore, the timed consumption of either 1.6 or 3.2 mg/kg BAE attenuated a 17 ± 2.4% (P < 0.05) decline in neutrophil phagocytic capability of opsonised FITC-Escherichia coli observed 6 h post-exercise in the placebo group. Similarly, a dose-dependent increase in neutrophil surface expression of complement receptor-3 complex (CR3, critical for effective phagocytosis of opsonised microbes), was observed 6 h post-exercise in both 1.6 and 3.2 mg/kg BAE intervention groups.

Conclusions: Consumption of BAE (>1.6 mg/kg) 1 h prior to exercise facilitated recovery from exercise-induced oxidative stress and preserved circulating neutrophil function. This study provides data to underpin a larger study designed to evaluate the efficacy of timed BAE consumption on post-exercise recovery and innate immunity.

Autophagy as a Therapeutic Target to Enhance Aged Muscle Regeneration

Skeletal muscle has remarkable regenerative capacity, relying on precise coordination between resident muscle stem cells (satellite cells) and the immune system. The age-related decline in skeletal muscle regenerative capacity contributes to the onset of sarcopenia, prolonged hospitalization, and loss of autonomy. Although several age-sensitive pathways have been identified, further investigation is needed to define targets of cellular dysfunction. Autophagy, a process of cellular catabolism, is emerging as a key regulator of muscle regeneration affecting stem cell, immune cell, and myofiber function. Muscle stem cell senescence is associated with a suppression of autophagy during key phases of the regenerative program. Macrophages, a key immune cell involved in muscle repair, also rely on autophagy to aid in tissue repair. This review will focus on the role of autophagy in various aspects of the regenerative program, including adult skeletal muscle stem cells, monocytes/macrophages, and corresponding age-associated dysfunction. Furthermore, we will highlight rejuvenation strategies that alter autophagy to improve muscle regenerative function.

Effects of Acute and Chronic Exercise on Immunological Parameters in the Elderly Aged: Can Physical Activity Counteract the Effects of Aging?

Immunosenescence is characterized by deterioration of the immune system caused by aging which induces changes to innate and adaptive immunity. Immunosenescence affects function and phenotype of immune cells, such as expression and function of receptors for immune cells which contributes to loss of immune function (chemotaxis, intracellular killing). Moreover, these alterations decrease the response to pathogens, which leads to several age-related diseases including cardiovascular disease, Alzheimer's disease, and diabetes in older individuals. Furthermore, increased risk of autoimmune disease and chronic infection is increased with an aging immune system, which is characterized by a pro-inflammatory environment, ultimately leading to accelerated biological aging. During the last century, sedentarism rose dramatically, with a concomitant increase in certain type of cancers (such as breast cancer, colon, or prostate cancer), and autoimmune disease. Numerous studies on physical activity and immunity, with focus on special populations (i.e., people with diabetes, HIV patients) demonstrate that chronic exercise enhances immunity. However, the majority of previous work has focused on either a pathological population or healthy young adults whilst research in elderly populations is scarce. Research conducted to date has primarily focused on aerobic and resistance exercise training and its effect on immunity. This review focuses on the potential for exercise training to affect the aging immune system. The concept is that some lifestyle strategies such as high-intensity exercise training may prevent disease through the attenuation of immunosenescence. In this context, we take a top-down approach and review the effect of exercise and training on immunological parameters in elderly at rest and during exercise in humans, and how they respond to different modes of training. We highlight the impact of these different exercise modes on immunological parameters, such as cytokine and lymphocyte concentration in elderly individuals.

Reversing the immune ageing clock: lifestyle modifications and pharmacological interventions

It is widely accepted that ageing is accompanied by remodelling of the immune system, including reduced numbers of naïve T cells, increased senescent or exhausted T cells, compromise to monocyte, neutrophil and natural killer cell function and an increase in systemic inflammation. In combination these changes result in increased risk of infection, reduced immune memory, reduced immune tolerance and immune surveillance, with significant impacts upon health in old age. More recently it has become clear that the rate of decline in the immune system is malleable and can be influenced by environmental factors such as physical activity as well as pharmacological interventions. This review discusses briefly our current understanding of immunesenescence and then focuses on lifestyle interventions and therapeutic strategies that have been shown to restore immune functioning in aged individuals.

Physical Activity, Sitting Time, and Mortality From Inflammatory Diseases in Older Adults

Objective: The aim of this study was to examine the independent and combined associations of physical activity (PA) and sitting time (ST) with long-term mortality attributed to inflammatory causes other than cardiovascular disease (CVD) and cancer in a national cohort of older adults in Spain. Design: Prospective study. Setting and Participants: A cohort of 3,677 individuals (1,626 men) aged ≥60 years was followed-up during 14.3 years. Measures: At baseline, individuals reported PA and ST. The study outcome was death from inflammatory diseases when CVD or cancer mortality was excluded. This outcome was classified into infectious and non-infectious conditions. Analyses were performed with Cox regression and adjusted for PA, ST, and other main confounders (age, sex, educational level, smoking, alcohol consumption, body mass index, and chronic conditions). Results: During follow-up, 286 deaths from inflammatory diseases (77 from infectious diseases) were identified. Compared to individuals who defined themselves as inactive/less active, mortality from inflammatory diseases was lower in those who were moderately active (hazard ratio [HR] = 0.67, 95% confidence interval [CI] = 0.50-0.90) or very active (HR = 0.48, 95%CI = 0.33-0.68), independently of ST. Also, being seated ≥7 h/d vs. <7 h/d was linked to higher mortality (HR = 1.38, 95%CI = 1.02-1.87). The largest risk of mortality was observed in inactive/less active individuals with ST≥7 h/d (HR = 2.29, 95%CI = 1.59-3.29) compared to those with moderate/very PA and ST <7 h/d. Low PA and high ST were consistently associated with a higher risk of mortality from non-infectious inflammatory causes. Associations of PA and ST with mortality from infectious inflammatory causes showed a similar trend, but most of them did not reach statistical significance. Conclusions: Low PA and high ST were independently associated with higher mortality from inflammatory diseases other than CVD or cancer in older adults. Interventions addressing simultaneously both behaviors could have greater benefits than those focusing on only one of them.

Physical Activity, Sitting Time, and Mortality From Inflammatory Diseases in Older Adults

Objective: The aim of this study was to examine the independent and combined associations of physical activity (PA) and sitting time (ST) with long-term mortality attributed to inflammatory causes other than cardiovascular disease (CVD) and cancer in a national cohort of older adults in Spain. Design: Prospective study. Setting and Participants: A cohort of 3,677 individuals (1,626 men) aged ≥60 years was followed-up during 14.3 years. Measures: At baseline, individuals reported PA and ST. The study outcome was death from inflammatory diseases when CVD or cancer mortality was excluded. This outcome was classified into infectious and non-infectious conditions. Analyses were performed with Cox regression and adjusted for PA, ST, and other main confounders (age, sex, educational level, smoking, alcohol consumption, body mass index, and chronic conditions). Results: During follow-up, 286 deaths from inflammatory diseases (77 from infectious diseases) were identified. Compared to individuals who defined themselves as inactive/less active, mortality from inflammatory diseases was lower in those who were moderately active (hazard ratio [HR] = 0.67, 95% confidence interval [CI] = 0.50-0.90) or very active (HR = 0.48, 95%CI = 0.33-0.68), independently of ST. Also, being seated ≥7 h/d vs. <7 h/d was linked to higher mortality (HR = 1.38, 95%CI = 1.02-1.87). The largest risk of mortality was observed in inactive/less active individuals with ST≥7 h/d (HR = 2.29, 95%CI = 1.59-3.29) compared to those with moderate/very PA and ST <7 h/d. Low PA and high ST were consistently associated with a higher risk of mortality from non-infectious inflammatory causes. Associations of PA and ST with mortality from infectious inflammatory causes showed a similar trend, but most of them did not reach statistical significance. Conclusions: Low PA and high ST were independently associated with higher mortality from inflammatory diseases other than CVD or cancer in older adults. Interventions addressing simultaneously both behaviors could have greater benefits than those focusing on only one of them.

Physical Activity, Immune System, and the Microbiome in Cardiovascular Disease

Cardiovascular health is a primary research focus, as it is a leading contributor to mortality and morbidity worldwide, and is prohibitively costly for healthcare. Atherosclerosis, the main driver of cardiovascular disease, is now recognized as an inflammatory disorder. Physical activity (PA) may have a more important role in cardiovascular health than previously expected. This review overviews the contribution of PA to cardiovascular health, the inflammatory role of atherosclerosis, and the emerging evidence of the microbiome as a regulator of 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.

Debunking the Myth of Exercise-Induced Immune Suppression: Redefining the Impact of Exercise on Immunological Health Across the Lifespan

Epidemiological evidence indicates that regular physical activity and/or frequent structured exercise reduces the incidence of many chronic diseases in older age, including communicable diseases such as viral and bacterial infections, as well as non-communicable diseases such as cancer and chronic inflammatory disorders. Despite the apparent health benefits achieved by leading an active lifestyle, which imply that regular physical activity and frequent exercise enhance immune competency and regulation, the effect of a single bout of exercise on immune function remains a controversial topic. Indeed, to this day, it is perceived by many that a vigorous bout of exercise can temporarily suppress immune function. In the first part of this review, we deconstruct the key pillars which lay the foundation to this theory-referred to as the "open window" hypothesis-and highlight that: (i) limited reliable evidence exists to support the claim that vigorous exercise heightens risk of opportunistic infections; (ii) purported changes to mucosal immunity, namely salivary IgA levels, after exercise do not signpost a period of immune suppression; and (iii) the dramatic reductions to lymphocyte numbers and function 1-2 h after exercise reflects a transient and time-dependent redistribution of immune cells to peripheral tissues, resulting in a heightened state of immune surveillance and immune regulation, as opposed to immune suppression. In the second part of this review, we provide evidence that frequent exercise enhances-rather than suppresses-immune competency, and highlight key findings from human vaccination studies which show heightened responses to bacterial and viral antigens following bouts of exercise. Finally, in the third part of this review, we highlight that regular physical activity and frequent exercise might limit or delay aging of the immune system, providing further evidence that exercise is beneficial for immunological health. In summary, the over-arching aim of this review is to rebalance opinion over the perceived relationships between exercise and immune function. We emphasize that it is a misconception to label any form of acute exercise as immunosuppressive, and, instead, exercise most likely improves immune competency across the lifespan.

Major features of immunesenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood

It is widely accepted that aging is accompanied by remodelling of the immune system including thymic atrophy and increased frequency of senescent T cells, leading to immune compromise. However, physical activity, which influences immunity but declines dramatically with age, is not considered in this literature. We assessed immune profiles in 125 adults (55-79 years) who had maintained a high level of physical activity (cycling) for much of their adult lives, 75 age-matched older adults and 55 young adults not involved in regular exercise. The frequency of naïve T cells and recent thymic emigrants (RTE) were both higher in cyclists compared with inactive elders, and RTE frequency in cyclists was no different to young adults. Compared with their less active counterparts, the cyclists had significantly higher serum levels of the thymoprotective cytokine IL-7 and lower IL-6, which promotes thymic atrophy. Cyclists also showed additional evidence of reduced immunesenescence, namely lower Th17 polarization and higher B regulatory cell frequency than inactive elders. Physical activity did not protect against all aspects of immunesenescence: CD28^-ve CD57^+ve senescent CD8 T-cell frequency did not differ between cyclists and inactive elders. We conclude that many features of immunesenescence may be driven by reduced physical activity with age.

Neutrophil and Monocyte Bactericidal Responses to 10 Weeks of Low-Volume High-Intensity Interval or Moderate-Intensity Continuous Training in Sedentary Adults

Neutrophils and monocytes are key components of the innate immune system that undergo age-associated declines in function. This study compared the impact of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on immune function in sedentary adults. Twenty-seven (43 ± 11 years) healthy sedentary adults were randomized into ten weeks of either a HIIT (>90% maximum heart rate) or MICT (70% maximum heart rate) group training program. Aerobic capacity (VO_2peak), neutrophil and monocyte bacterial phagocytosis and oxidative burst, cell surface receptor expression, and systemic inflammation were measured before and after the training. Total exercise time commitment was 57% less for HIIT compared to that for MICT while both significantly improved VO_2peak similarly. Neutrophil phagocytosis and oxidative burst and monocyte phagocytosis and percentage of monocytes producing an oxidative burst were improved by training similarly in both groups. Expression of monocyte but not neutrophil CD16, TLR2, and TLR4 was reduced by training similarly in both groups. No differences in systemic inflammation were observed for training; however, leptin was reduced in the MICT group only. With similar immune-enhancing effects for HIIT compared to those for MICT at 50% of the time commitment, our results support HIIT as a time efficient exercise option to improve neutrophil and monocyte function.