Effects of anaerobic exercise on the immune system in eight- to seventeen-year-old trained and untrained boys

Immune Function Response Following a Low-carbohydrate, High-fat Diet (LCHFD) in Patients with Type 2 Diabetes

Background: Type 2 diabetes is a chronic metabolic disorder that can result in micro- and macrovascular complications and is complicated by an impaired healing process. Research suggests that both dietary factors and habitual physical activity influence the hemostatic system through several pathways. Objectives: The study attempted to investigate if a low-carbohydrate, high-fat diet (LCHFD), on its own or in conjunction with physical activity, could alter hematologic variables in patients with type 2 diabetes. Methods: Participants (n = 39; 31 - 71 y.) were assigned into three groups, which included either a 16 week continuous physical activity program with the consumption of an LCHFD (ExDG) (n = 13; 41 - 71 y), consuming only a LCHFD group (DietG) (n = 13; 31 - 71 y.), or a control group (ConG) (n = 13; 44 - 69 y). Participants in the ExDG were advised only to consume a diet high in fat and not consume more than 50 g of carbohydrates per day. Furthermore, participants had to walk a minimum of 10000 steps per day. The DietG were instructed to only consume a diet high in fat and low in carbohydrates, where the ConG continued with their normal daily routine. Results: No significant changes (P > 0.05) were observed in white blood cell count, neutrophils, lymphocytes, eosinophils, basophils, hemoglobin, red blood cell count, mean corpuscular volume, hematocrit, mean corpuscular hemoglobin, platelets, red blood cell distribution width, mean corpuscular hemoglobin concentration, and C-reactive protein following ExDG, DietG or in the ConG. Conclusions: A LCHFD on its own or in conjunction with physical activity does not have any effect on the measured hematologic variables in patients with type 2 diabetes. This may be due to the current popular recommendation of LCHFD not being useful in type 2 diabetics and 10000 steps being of insufficient intensity to improve hematologic parameters in type 2 diabetics.

Exercise and Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal recessive, inherited congenital disease caused by the mutation of the family autosomal CF gene, with cumulative exocrine secretion characterized by inflammation, tracheal remodeling, and mucus accumulation. With the development of modern medical technology, CF patients are living longer lives and receiving more and more treatments, including traditional drugs, physical therapy, and gene therapy. Exercise is widely used to prevent and treat metabolic diseases such as cardiovascular diseases, obesity, diabetes, and metabolic syndrome. Regular exercise is beneficial to aerobic capacity and lung health. Exercise therapy has been of great interest since people realized that CF can be affected by exercise. Exercise alone can be used as an ACT (airway clearance technique), which promotes the removal of mucosal cilia. Exercise therapy is more easily accepted by any society, which helps to normalize the lives of CF patients, rather than placing a psychological burden on them. In this chapter, we will review the latest research progress about exercise in CF.

Long-term swimming training modifies acute immune cell response to a high-intensity session

PURPOSE

Long-term training influence on athletes' immune cell response to acute exercise has been poorly studied, despite the complexity of both chronic and acute adaptations induced by training. The purpose of the study is to study the influence of a 4-month swimming training cycle on the immune cell response to a high-intensity training session, during 24 h of recovery, considering sex, maturity, and age group.

METHODS

Forty-three swimmers (16 females, 14.4 ± 1.1 years; 27 males, 16.2 ± 2.0) performed a standardized high-intensity session, after the main competition of the first (M1), and second (M2) macrocycles. Blood samples were collected before (Pre), immediately after (Post), 2 h after (Post2h) and 24 h after (Post24h) exercise. Haemogram and lymphocytes subsets were assessed by an automatic cell counter and by flow cytometry, respectively. Subjects were grouped according to sex, competitive age groups, or pubertal Tanner stages. Results express the percentage of relative differences from Pre to Post, Post2h and Post24h. Upper respiratory symptoms (URS) and training load were quantified.

RESULTS

At M2, we observed smaller increases of leukocytes (M1: 14.0 ± 36.3/M2: 2.33 ± 23.0%) and neutrophils (M1: 57.1 ± 71.6/M2: 38.9 ± 49.9%) at Post; and less efficient recoveries of total lymphocytes (M1: - 22.0 ± 20.1/M2: - 30.0 ± 18.6%) and CD19⁺ (M1: 4.09 ± 31.1/M2: - 19.1 ± 24.4%) at Post2h. At Post2h, the increment of CD4⁺/CD8⁺ was smaller in youth (M1: 21.5 ± 16.0/M2: 9.23 ± 21.4%), and bigger in seniors (M1: 3.68 ± 9.21/M2: 23.2 ± 15.0%); and at Post24h late pubertal swimmers' CD16⁺56⁺ recovered less efficiently (M1: - 0.66 ± 34.6/M2: - 20.5 ± 34.2%).

CONCLUSIONS

The training cycle induced an attenuated immune change immediately after exercise and a less efficient recovery of total lymphocytes, involving an accentuated CD19⁺ decrease. The concomitant higher URS frequency suggests a potential immune depression and a longer interval of susceptibility to infection.

Exercise and Immune Function in Children

Exercise immunology is one of the fastest growing disciplines of the past 2 decades. Unfortunately, the number of investigations devoted to the pediatric population remains low, and our understanding of the interaction between acute and chronic exercise and the immune system in youth is relatively deficient. In general, healthy children experience smaller overall perturbations to the immune system in response to an acute bout of exercise as compared with adults, and they demonstrate a faster recovery of the immune system following exercise. There is only limited evidence to suggest that moderate to high levels of habitual physical activity are associated with a reduction in the incidence of infection and illness in youth. Special consideration should be made for the young athlete training and competing during an illness or infection. Some of the unique exercise responses of the immune system in children may have important clinical relevance, but much more work is required in this area.

POSITIVE study: physical exercise program in non-operable lung cancer patients undergoing palliative treatment

Background

Patients with advanced stage non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC) often experience multidimensional impairments, affecting quality of life during their course of disease. In lung cancer patients with operable disease, several studies have shown that exercise has a positive impact on quality of life and physical functioning. There is limited evidence regarding efficacy for advanced lung cancer patients undergoing palliative treatment. Therefore, the POSITIVE study aims to evaluate the benefit of a 24-week exercise intervention during palliative treatment in a randomized controlled setting.

Methods/design

The POSITIVE study is a randomized, controlled trial investigating the effects of a 24-week exercise intervention during palliative treatment on quality of life, physical performance and immune function in advanced, non-operable lung cancer patients. 250 patients will be recruited in the Clinic for Thoracic Diseases in Heidelberg, enrolment begun in November 2013. Main inclusion criterion is histologically confirmed NSCLC (stage IIIa, IIIb, IV) or SCLC (Limited Disease-SCLC, Extensive Disease-SCLC) not amenable to surgery. Patients are randomized into two groups. Both groups receive weekly care management phone calls (CMPCs) with the goal to assess symptoms and side effects. Additionally, one group receives a combined resistance and endurance training (3x/week). Primary endpoints are quality of life assessed by the Functional Assessment of Cancer Therapy for patients with lung cancer (FACT-L, subcategory Physical Well-Being) and General Fatigue measured by the Multidimensional Fatigue Inventory (MFI-20). Secondary endpoints are physical performance (maximal voluntary isometric contraction, 6-min walk distance), psychosocial (depression and anxiety) and immunological parameters and overall survival.

Discussion

The aim of the POSITIVE trial is the evaluation of effects of a 24-week structured and guided exercise intervention during palliative treatment stages. Analysis of various outcomes (such as quality of life, physical performance, self-efficacy, psychosocial and immunological parameters) will contribute to a better understanding of the potential of exercise in advanced lung cancer patients. In contrast to other studies with advanced oncological patients the POSITIVE trial provides weekly phone calls to support patients both in the intervention and control group and to segregate the impact of physical activity on quality of life.

Trial registration

ClinicalTrials.gov NCT02055508 (Date: December 12, 2013)

Immune cell changes in response to a swimming training session during a 24-h recovery period

Understanding the impact of training sessions on the immune response is crucial for the adequate periodization of training, to prevent both a negative influence on health and a performance impairment of the athlete. This study evaluated acute systemic immune cell changes in response to an actual swimming session, during a 24-h recovery period, controlling for sex, menstrual cycle phases, maturity, and age group. Competitive swimmers (30 females, 15 ± 1.3 years old; and 35 males, 16.5 ± 2.1 years old) performed a high-intensity training session. Blood samples were collected before, immediately after, 2 h after, and 24 h after exercise. Standard procedures for the assessment of leukogram by automated counting (Coulter LH 750, Beckman) and lymphocytes subsets by flow cytometry (FACS Calibur BD, Biosciences) were used. Subjects were grouped according to competitive age groups and pubertal Tanner stages. Menstrual cycle phase was monitored. The training session induced neutrophilia, lymphopenia, and a low eosinophil count, lasting for at least 2 h, independent of sex and maturity. At 24 h postexercise, the acquired immunity of juniors (15-17 years old), expressed by total lymphocytes and total T lymphocytes (CD3(+)), was not fully recovered. This should be accounted for when planning a weekly training program. The observed lymphopenia suggests a lower immune surveillance at the end of the session that may depress the immunity of athletes, highlighting the need for extra care when athletes are exposed to aggressive environmental agents such as swimming pools.

A standardized randomized 6-month aerobic exercise-training down-regulated pro-inflammatory genes, but up-regulated anti-inflammatory, neuron survival and axon growth-related genes

There is considerable support for the view that aerobic exercise may confer cognitive benefits to mild cognitively impaired elderly persons. However, the biological mechanisms mediating these effects are not entirely clear. As a preliminary step towards informing this gap in knowledge, we enrolled older adults confirmed to have mild cognitive impairment (MCI) in a 6-month exercise program. Male and female subjects were randomized into a 6-month program of either aerobic or stretch (control) exercise. Data collected from the first 10 completers, aerobic exercise (n=5) or stretch (control) exercise (n=5), were used to determine intervention-induced changes in the global gene expression profiles of the aerobic and stretch groups. Using microarray, we identified genes with altered expression (relative to baseline values) in response to the 6-month exercise intervention. Genes whose expression were altered by at least two-fold, and met the p-value cutoff of 0.01 were inputted into the Ingenuity Pathway Knowledge Base Library to generate gene-interaction networks. After a 6-month aerobic exercise-training, genes promoting inflammation became down-regulated, whereas genes having anti-inflammatory properties and those modulating immune function or promoting neuron survival and axon growth, became up-regulated (all fold change≥±2.0, p<0.01). These changes were not observed in the stretch group. Importantly, the differences in the expression profiles correlated with significant improvement in maximal oxygen uptake (VO2max) in the aerobic program as opposed to the stretch group. We conclude that three distinct cellular pathways may collectively influence the training effects of aerobic exercise in MCI subjects. We plan to confirm these effects using rt-PCR and correlate such changes with the cognitive phenotype.

A pediatric perspective on inflammation and oxidative stress in response to exercise

Dr. Oded Bar-Or was a giant in the area of pediatric exercise science and made numerous contributions to the health of children around the world. He also had a significant impact on a relatively new area of pediatric exercise science — pediatric exercise immunology. Under his supervision, some aspects of the immunobiology of exercise have been unravelled from a pediatric perspective. In general, healthy children experience less inflammatory stress in response to standardized exercise, while demonstrating an exercise-induced elevation in the anabolic cytokine IL-8. Mechanisms for the maturity- and age-dependent changes in cytokine responses to exercise are unknown, but may involve oxidative stress. Studies of oxidative stress and exercise in children are scant, but preliminary data suggests that, like the inflammatory cytokine response to exercise, children may experience less oxidative stress in response to intense exercise. We propose that the links between exercise, inflammatory and oxidative stress, and growth factors will be important to understand in the context of how exercise contributes to optimal growth and development during childhood. This understanding will be particularly relevant for childhood diseases that restrict growth.

Effects of 30 min of aerobic exercise on gene expression in human neutrophils

Relatively brief bouts of exercise alter gene expression in peripheral blood mononuclear cells (PBMCs), but whether exercise changes gene expression in circulating neutrophils (whose numbers, like PBMCs, increase) is not known. We hypothesized that exercise would activate neutrophil genes involved in apoptosis, inflammation, and cell growth and repair, since these functions in leukocytes are known to be influenced by exercise. Blood was sampled before and immediately after 30 min of constant, heavy (∼80% peak O2uptake) cycle ergometer exercise in 12 healthy men (19–29 yr old) of average fitness. Neutrophils were isolated using density gradients; RNA was hybridized to Affymetrix U133+2 Genechip arrays. With false discovery rate (FDR) <0.05 with 95% confidence, a total of 526 genes were differentially expressed between before and after exercise. Three hundred and sixteen genes had higher expression after exercise. The Jak/STAT pathway, known to inhibit apoptosis, was significantly activated (EASE score, P < 0.005), but 14 genes were altered in a way likely to accelerate apoptosis as well. Similarly, both proinflammatory (e.g., IL-32, TNFSF8, and CCR5) and anti-inflammatory (e.g., ANXA1) were affected. Growth and repair genes like AREG and FGF2 receptor genes (involved in angiogenesis) were also activated. Finally, a number of neutrophil genes known to be involved in pathological conditions like asthma and arthritis were altered by exercise, suggesting novel links between physical activity and disease or its prevention. In summary, brief heavy exercise leads to a previously unknown substantial and significant alteration in neutrophil gene expression.

Puberty effects on NK cell responses to exercise and carbohydrate intake in boys

Previous research has demonstrated that younger versus older animals and humans experience smaller perturbations in natural killer (NK) cells in response to physiological stress.

PURPOSE

To determine whether the smaller perturbations in NK cells induced by strenuous exercise and carbohydrate (CHO) intake, previously reported in children, are influenced by puberty.

METHODS

Twenty 12-yr-old boys, distinguished as prepubertal (Tanner (T) 1, N = 7), early pubertal (T2, N = 7), or pubertal (T3-5, N = 6), cycled for 60 min at 70% VO(2max) while drinking 6% CHO (CT) or flavored water (WT). Blood was collected at rest and during (30 and 60 min) and following (30 and 60 min) exercise to identify NK cells as CD3(-)CD56(dim) or CD3(-)CD56(dim). CD69 expression on CD3(-)CD56(+) cells was also determined.

RESULTS

A puberty x CHO x exercise interaction was found for the proportion, but not number, of CD56(dim) cells (P = 0.06). CD56(dim) cell counts were lower in CT versus WT (P < 0.001). Responses of CD56(bright) proportions (P = 0.007) and counts (P = 0.03) depended on pubertal status, but not CHO. The CD56(bright):CD56(dim) ratio remained stable during exercise, but during recovery was higher in T1 and T3-5 versus T2 (P = 0.08) and in CT versus WT (P = 0.04). During recovery, CD3(-)CD56(+) cells expressed higher levels of CD69 (P = 0.01), with no change in the proportion of CD69(+) cells.

CONCLUSION

These results confirm the influence of puberty on the distribution of NK cell subsets in response to exercise and CHO intake. Increased CD69 expression suggests that NK cells increase activation status during recovery from physiological stress.

Effects of acute exercise on neutrophils in pediatric acute lymphoblastic leukemia survivors: a pilot study

PURPOSE

This nonrandomized controlled trial was designed to investigate the effects of acute exercise on neutrophil count and function in children and adolescents receiving maintenance treatment for acute lymphoblastic leukemia (ALL) compared to matched controls.

METHODS

Participants (n = 10; 4 ALL patients and 6 healthy matched controls) were males between the ages of 7 to 18 years. On visit 1, participants completed an incremental exercise test to volitional exhaustion on a treadmill to determine peak aerobic fitness (VO(2peak)). On visit 2, participants completed a 30-minute exercise session consisting of an intermittent run-walk on a treadmill at 70% to 85% of VO(2) peak with blood sampling completed at 5 time points: fasting, preexercise, postexercise, 1-hour postexercise, and 2-hour postexercise.

RESULTS

A significant increase in absolute neutrophil count from preexercise to postexercise was observed in both groups (P = 0.011). Neutrophil oxidative capacity was significantly depressed in the ALL group at the basal level (P = 0.029), however, it increased in both groups after exercise and stimulation.

CONCLUSIONS

This preliminary study suggests that 30 minutes of moderate intensity exercise in ALL patients receiving maintenance therapy provides a similar neutrophil response to that of healthy age and sex-matched controls.

Sex-based effects on the distribution of NK cell subsets in response to exercise and carbohydrate intake in adolescents

Carbohydrate (CHO) supplementation and female sex independently influence the natural killer (NK) cell response to acute exercise. Consequently, this study sought to elucidate sex-based differences in the distribution of NK cell subsets (i.e., CD56dimand CD56bright) in response to exercise and CHO intake. Twenty-two healthy 14-yr-old girls ( n = 11) and boys ( n = 11) cycled for 60 min at 70% maximal oxygen consumption while drinking 6% CHO (CT) or flavored water (WT). Blood was collected at rest, during exercise (30 and 60 min), and during recovery (30 and 60 min) to identify CD3−CD56dimand CD3−CD56brightNK cells. The activation marker CD69 was also determined on CD3−CD56+cells. CD56dimresponses, expressed as proportions or cell counts, were greater ( P ≤ 0.01) in girls by 67 and 105%, respectively. CD56brightcell counts ( P = 0.006), but not CD56brightproportions ( P = 0.89), were greater in girls by 82%. Both CD56dimand CD56brightsubset responses, expressed as proportions or cell counts, were lower ( P ≤ 0.01) in CT vs. WT by 33–36%. The CD56bright-to-CD56dimratio decreased at 30 min of exercise but increased during recovery ( P < 0.001), with no effect of sex or CHO. Regardless of trial, CD3−CD56+cells expressed ∼18% higher levels of CD69 during recovery in girls but not boys ( P = 0.03), despite similar proportions and counts of CD69+cells. These results demonstrate sex-based differences in the distribution of NK cell subsets and activation status in response to exercise, but not CHO intake, and further support the need to control for sex in exercise immunology studies.

Cardiovascular disease and toxicities related to HIV infection and its therapies

Cardiovascular manifestations of HIV vary according to disease stage, treatment regimen and geographical location. Common cardiac complications of HIV disease in patients off highly active antiretroviral therapy (HAART) include dilated cardiomyopathy, myocarditis, pericardial effusion, endocarditis, pulmonary hypertension and non-antiretroviral drug-related cardiotoxicity. However, with the introduction of HAART that has substantially modified the course of HIV disease by lengthening survival, additional cardiovascular consequences are a result of the metabolic syndrome with a propensity toward hyperlipidaemia and atherosclerotic heart disease. Because most of the world's HIV-infected patients have not been treated with HAART, the principal HIV-associated cardiovascular manifestations of patients off HAART are reviewed and new knowledge about the prevalence, pathogenesis and treatment in the HAART era are emphasised in this review. Exercise, a nonpharmacological approach to treating HAART-associated metabolic syndrome, is also discussed.

Impact of HIV and highly active antiretroviral therapy on leukocyte adhesion molecules, arterial inflammation, dyslipidemia, and atherosclerosis

Highly active antiretroviral therapy (HAART) has greatly extended the lives of people infected with the human immunodeficiency virus (HIV). This reduced risk of early death from opportunistic infections or other sequelae of HIV infection, however, means that other possible causes of death emerge. Myocardial infarction has become a matter of particular concern. Two of the main sources of cardiovascular disease in this population are believed to be vascular inflammation and dyslipidemia. We review the evidence for this hypothesis and discuss the relationship of HIV to vascular inflammation. Current treatment guidelines do not recommend the immediate initiation of HAART unless warranted, potentially allowing long-term, unchecked viral impact on the development of atherosclerosis. Finally, we consider the protease inhibitors traditionally included in HAART regimens and their relationship to the development of dyslipidemia, as well as other classes of antiretrovirals, such as the non-nucleoside reverse transcriptase inhibitors, which might be a better choice for patients with cardiovascular risks. Other strategies, such as pharmacologic, nutritional, and physical activity interventions are discussed. The patients who might benefit most are those in whom the precursors of vascular plaques, such as fatty streak, smooth muscle cell, macrophage, and T-lymphocyte aggregation not yet identified by echocardiographic and biopsy findings have already developed as a result of unchecked viral inflammation and replication.

Chronic fatigue syndrome: the need for subtypes

Chronic fatigue syndrome (CFS) is an important condition confronting patients, clinicians, and researchers. This article provides information concerning the need for appropriate diagnosis of CFS subtypes. We first review findings suggesting that CFS is best conceptualized as a separate diagnostic entity rather than as part of a unitary model of functional somatic distress. Next, research involving the case definitions of CFS is reviewed. Findings suggest that whether a broad or more conservative case definition is employed, and whether clinic or community samples are recruited, these decisions will have a major influence in the types of patients selected. Review of further findings suggests that subtyping individuals with CFS on sociodemographic, functional disability, viral, immune, neuroendocrine, neurology, autonomic, and genetic biomarkers can provide clarification for researchers and clinicians who encounter CFS' characteristically confusing heterogeneous symptom profiles. Treatment studies that incorporate subtypes might be particularly helpful in better understanding the pathophysiology of CFS. This review suggests that there is a need for greater diagnostic clarity, and this might be accomplished by subgroups that integrate multiple variables including those in cognitive, emotional, and biological domains.

Natural killer cell lytic activity and CD56dim and CD56bright cell distributions during and after intensive training

The purpose of this study was to examine the impact of intensive training for competitive sports on natural killer (NK) cell lytic activity and subset distribution. Eight female college-level volleyball players undertook 1 mo of heavy preseason training. Volleyball drills were performed 5 h/day, 6 days/wk. Morning resting blood samples were collected before training (Pre), on the 10th day of training (During), 1 day before the end of training (End), and 1 wk after intensive training had ceased (Post). CD3-CD16brightCD56dim (CD56dim NK), CD3-CD16dim/-CD56bright NK (CD56bright NK), and CD3+CD16-CD56dim (CD56dim T) cells in peripheral blood were determined by flow cytometry. The circulating count of CD56dim NK cells (the predominant population, with a high cytotoxicity) did not change, nor did the counts for other leukocyte subsets. However, counts for CD56bright NK and CD56dim T cells (subsets with a lower cytotoxicity) increased significantly ( P < 0.01) in response to the heavy training. Overall NK cell cytotoxicity decreased from Pre to End ( P = 0.002), with a return to initial values at Post. Lytic units per NK cell followed a similar pattern ( P = 0.008). Circulating levels of interleukin-6, interferon-γ, and tumor necrosis factor-α remained unchanged. These results suggest that heavy training can decrease total NK cell cytotoxicity as well as lytic units per NK cell. Such effects may reflect in part an increase in the proportion of circulating NK cells with a low cytotoxicity.

Sex differences in immune responses and immune reactivity to stress in adolescents

The immune system is the body's major defense mechanism against disease. However, psychosocial factors, such as stress, can modulate various immune responses. Although they have been examined in adult humans and other animals, sex differences in immune responses and immune reactivity to stress have rarely been examined in adolescents, particularly comparing healthy and asthmatic adolescents. In 151 healthy and asthmatic high school adolescents (91 females and 60 males), natural killer cell (NK) cytotoxicity, polymorphonuclear leukocyte (PMN) superoxide release, lymphocyte proliferative responses, and CD subsets were measured twice: once during mid-semester and again during final examinations. There was little difference in these measures between healthy and asthmatic adolescents. Similarly, only sex difference was noted in NK cytotoxicity at a 25:1 effector-to-target cell ratio, with males showing significantly higher responses than females. For PMN superoxide release, females significantly increased their responses during final examinations, whereas males demonstrated no changes. For lymphocyte proliferative responses, both females and males increased their responses during final examinations, but the magnitude of increase was much greater in males. Furthermore, racial comparisons indicated that African American adolescents (n = 16), as compared with Caucasian adolescents (n = 128), had significantly higher responses in PMN superoxide release to N-Formyl-Met-Leu-Phe (FMLP) activation during mid-semester and lymphocyte proliferative responses at both time points. Nevertheless, the overall findings indicate limited differences in immune responses and immune reactivity to stress in adolescents between males and females, healthy and asthmatic adolescents, and Caucasians and African Americans. However, further investigations with larger samples are warranted.

Effect of intense wrestling exercise on leucocytes and adhesion molecules in adolescent boys

BACKGROUND

In adults, exercise is a powerful and natural stimulator of immune cells and adhesion molecules. Far less is known about exercise responses during childhood and adolescence and whether or not exercise in "real life" activities of healthy adolescents influences immune responses.

OBJECTIVE

To determine if strenuous exercise leads to significant changes in leucocyte number and adhesion molecule expression in adolescent boys.

METHODS

Eleven healthy, high school boys, aged 14-18.5 years, performed a single, typical, 1.5 hour wrestling practice session. Blood was sampled before and after the session. Flow cytometry was used to evaluate changes in immune responses.

RESULTS

The exercise led to significant (p<0.05) and robust increases in granulocytes, monocytes, and all lymphocyte subpopulations. The most significant changes were observed for natural killer cells (p<0.0005). The number of T cytotoxic and T helper cells expressing CD62L increased significantly (p<0.002 and p<0.0005 respectively), as did the number of T cytotoxic and T helper cells not expressing CD62L (p<0.003 and p<0.009 respectively). The density of CD62L on lymphocytes decreased significantly with exercise (p<0.0005), whereas CD11a (p<0.01) and CD54 (p<0.01) increased.

CONCLUSIONS

The data show that an intense wrestling bout in adolescent boys leads to profound stimulation of the immune system. The role of these common changes in overall immune status and the development of the immune and haemopoietic systems has yet to be determined.

Effects of physical activity, body fat, and salivary cortisol on mucosal immunity in children

This study examined relationships among physical activity, body composition, and stress- and immunity-related variables in fifth grade children (10-11 yr) in Southern Ontario. The 29 boys and 32 girls, who participated in the study, performed a 20-m shuttle run for prediction of aerobic fitness. Bioelectrical impedance was used to assess relative body fat. Standardized questionnaires were used to determine physical activity-related variables and frequency of upper respiratory tract infection (URTI). Resting saliva samples were collected and tested for resting cortisol and resting secretory immunoglobulin A (SIgA). Subjects wore a pedometer for 48 h to estimate their average total distance traveled per day. SIgA was significantly correlated with reported URTIs but was not related to salivary cortisol, physical activity, fitness level, or relative body fat. Children who spent more time in sport activities and had higher aerobic fitness reported fewer "sick" days. Children with body fat higher than 25% reported significantly (P < 0.05) more sick days than the rest of the cohort. There were no gender differences in SIgA, URTI frequency, and cortisol levels. The test-retest reproducibility for salivary cortisol was 0.66 (P < 0.01), whereas long-term SIgA reproducibility was nonsignificant for repeated measurements taken after 6 wk. Resting secretory immunity was not strongly related to fitness and physical activity, but there was evidence that reduced physical activity and excess body fat can result in higher URTI incidence.

Cardiovascular monitoring and therapy for HIV-infected patients

Cardiovascular complications are important contributors to morbidity and mortality in HIV-infected patients. These complications can usually be detected at subclinical levels with monitoring, which can help guide targeted interventions. This article reviews available data on types and frequency of cardiovascular manifestations in HIV+ patients and proposes monitoring strategies aimed at early subclinical detection. In particular, we recommend routine echocardiography for HIV+ patients, even those with no evidence of cardiovascular disease. We also review preventive and therapeutic cardiovascular interventions. For procedures that have not been studied in HIV+ patients, we extrapolate from evidence-based guidelines for the general population.

Postexercise immune correlates in children with and without cystic fibrosis

INTRODUCTION

Previous studies have shown that children with cystic fibrosis (CF) are capable of mounting a normal immune response after the stress of exercise. However, few data are available regarding the underlying mechanisms by which this immune modulation occurs.

METHODS

In this study, lymphocyte and leukocyte cell counts were measured before and immediately after a single bout of exhaustive exercise in 25 children (ages 8-17 yr; 12 with CF and 13 healthy controls). Catecholamine, cortisol, and insulin levels, age, nutritional parameters, and static and dynamic lung function were measured as potential correlates for immune modulation. We hypothesized that catecholamine levels would be associated with the immune changes seen after exercise in children with CF.

RESULTS

Our results demonstrated positive correlations between age and the change in cell counts after exercise for white blood cells (r = 0.44, P < 0.03), lymphocytes (r = 0.60, P < 0.002), monocytes (r = 0.43, P < 0.03), and CD3-CD16+CD56+ cells (r = 0.61, P < 0.002). Lower increases in the lymphocyte and CD3-CD16+CD56+ cells were observed in the CF group. Changes in pre- and post-exercise norepinephrine levels were weakly correlated with the changes in granulocyte, lymphocyte, and monocyte cell counts. Changes in cortisol levels correlated with lymphocyte and CD19+ cell count changes for the CF group but not for the healthy controls. Within the CF group, the severity of lung disease (as indicated by a FEV1) was negatively correlated with changes in lymphocyte (r = -0.66, P < 0.02) and CD3-CD16+CD56+ cell counts (r = -0.67, P < 0.02).

CONCLUSION

The results suggest that postexercise changes in cell counts occur in an age dependent, norepinephrine associated manner. Disease severity for children with CF also appears to enhance the postexercise leukocytosis with pronounced increases seen in natural killer cells.

Effect of exercise on cytokines and growth mediators in prepubertal children

Many of the anabolic effects of exercise are mediated through insulin-like growth factor-I (IGF-I), but in adolescents, brief exercise training leads to reductions, rather than the expected increase, in circulating IGF-I. Certain cytokines--interleukin-(IL) 1beta (IL-1beta), IL-6 (IL-6), and tumor necrosis factor-alpha--are increased by exercise in adults and are known to inhibit IGF-I. To test the hypothesis that these cytokines might play a role in the adaptation to exercise, we measured the acute effects of exercise on selected cytokines and growth factors in 17 healthy 8- to 11-y-old children (4 females). Designed to mimic patterns and intensity of exercise found in the real lives of American children, the exercise protocol consisted of a 1.5-h soccer practice (of which about 40 min constituted of vigorous exercise). Pre- and postexercise urine and saliva samples were obtained in all subjects and both blood and urine in nine subjects. The exercise led to significant increases in circulating tumor necrosis factor-alpha (18 +/- 7%, p < 0.05) and IL-6 (125 +/- 35%, p < 0.01) as well as a significant increase in the antiinflammatory cytokine IL-1 receptor antagonist (33 +/- 10%, p < 0.01). Urine levels of IL-6 were also substantially increased by exercise (440 +/- 137%, p < 0.0001). Circulating levels of IGF-I were reduced to a small but significant degree (-6.4 +/- 3.2%, p < 0.05), although IGF-binding protein-1 (known to inhibit IGF-I) was substantially increased (156 +/- 40%, p < 0.001). Cytokines are systemically increased after relatively brief exercise in healthy children. This increase may alter critical anabolic agents such as IGF-I and its binding proteins.

Effects of exercise and training on natural killer cell counts and cytolytic activity: a meta-analysis

Meta-analysis techniques have been used to accumulate data from 94 studies describing the natural killer (NK) cell response of some 900 volunteers to acute and chronic exercise. NK cell numbers have been indicated in terms of CD3-CD16+CD56+, CD16+ or CD56+ phenotypes, and cytolytic activity has been expressed per 10,000 peripheral blood mononuclear cells or in terms of lytic units. Acute exercise has been categorised as sustained moderate (50 to 65% of aerobic power), sustained vigorous (>75% of aerobic power), brief maximal or 'supramaximal', prolonged, eccentric or resistance, and repeated exercise. In general, there was a marked increase in NK cell count at the end of exercise, probably attributable to a catecholamine-mediated demargination of cells. Following exercise, cell counts dropped to less than half of normal levels for a couple of hours but, except in unusual circumstances (e.g. prolonged, intense and stressful exercise), normal resting values are restored within 24 hours. If activity is both prolonged and vigorous, the decrease in NK cell counts and cytolytic activity may begin during the exercise session. Although the usual depression of NK cell count seems too brief to have major practical importance for health, there could be a cumulative adverse effect on immunosurveillance and health experience in athletes who induce such changes several times per week. There is a weak suggestion of an offsetting increase in resting NK cell counts and cytolytic action in trained individuals, and this merits further exploration in studies where effects of recent training sessions are carefully controlled.