Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 49
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Gerontology ; : 1-8, 2020 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-32585674

RESUMO

Social distancing has been adopted worldwide to control severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. Social isolation is likely to lead to a decline in physical activity, which could result in immune system dysfunction, thereby increasing infection susceptibility and exacerbating the pathophysiology of conditions that are common among older adults, including cardiovascular disease, cancer, and inflammatory disorders. Older adults and people living with these comorbidities are at a greater risk for complications during coronavirus disease 2019 (COVID-19). In this review, we discuss the negative impact of physical inactivity on immune function and showcase evidence that regular physical activity may be an effective strategy to counter some of the deleterious effects of social isolation. Furthermore, we briefly highlight key research questions in exercise immunology, with a focus on older adults in the context of COVID-19. Although it is worth emphasizing that there is no direct evidence that physical activity can prevent or treat -COVID-19, promoting an active lifestyle is a key intervention to counteract the effects of social isolation, especially in older adults and other at-risk individuals, such as those living with chronic diseases associated with ageing and lifestyle.

2.
Exerc Immunol Rev ; 26: 8-22, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32139352

RESUMO

Multiple studies in humans and animals have demonstrated the profound impact that exercise can have on the immune system. There is a general consensus that regular bouts of short-lasting (i.e. up to 45 minutes) moderate intensity exercise is beneficial for host immune defense, particularly in older adults and people with chronic diseases. In contrast, infection burden is reported to be high among high performance athletes and second only to injury for the number of training days lost during preparation for major sporting events. This has shaped the common view that arduous exercise (i.e. those activities practiced by high performance athletes/ military personnel that greatly exceed recommended physical activity guidelines) can suppress immunity and increase infection risk. However, the idea that exercise per se can suppress immunity and increase infection risk independently of the many other factors (e.g. anxiety, sleep disruption, travel, exposure, nutritional deficits, environmental extremes, etc.) experienced by these populations has recently been challenged. The purpose of this debate article was to solicit opposing arguments centered around this fundamental question in the exercise immunology field: can exercise affect immune function to increase susceptibility to infection. Issues that were contested between the debating groups include: (i) whether or not athletes are more susceptible to infection (mainly of the upper respiratory tract) than the general population; (ii) whether exercise per se is capable of altering immunity to increase infection risk independently of the multiple factors that activate shared immune pathways and are unique to the study populations involved; (iii) the usefulness of certain biomarkers and the interpretation of in vitro and in vivo data to monitor immune health in those who perform arduous exercise; and (iv) the quality of scientific evidence that has been used to substantiate claims for and against the potential negative effects of arduous exercise on immunity and infection risk. A key point of agreement between the groups is that infection susceptibility has a multifactorial underpinning. An issue that remains to be resolved is whether exercise per se is a causative factor of increased infection risk in athletes. This article should provide impetus for more empirical research to unravel the complex questions that surround this contentious issue in the field of exercise immunology.


Assuntos
Suscetibilidade a Doenças/imunologia , Exercício Físico , Imunidade , Infecções/imunologia , Animais , Atletas , Humanos , Sistema Imunitário
3.
J Appl Lab Med ; 3(4): 534-544, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-31639722

RESUMO

BACKGROUND: Currently it can take up to 5 days to rule out bloodstream infection. With the low yield of blood cultures (approximately 10%), a significant number of patients are potentially exposed to inappropriate therapy that can lead to adverse events. More rapid rule out can accelerate deescalation or cessation of antimicrobial therapy, improving patient outcomes. METHODS: A method is described, termed enzymatic template generation and amplification (ETGA), that universally and sensitively detects DNA polymerase activity liberated from viable bacteria and fungi isolated from blood culture samples as a measure of bloodstream infection. ETGA was applied in a diagnostic test format to identify negative blood cultures after an overnight incubation. Performance data for a prototype (Cognitor) and automated (Magnitor) version of the test are presented. RESULTS: The Cognitor manual assay displayed analytical reactivity for a panel of the 20 most prevalent causes of bloodstream infection, with a detection range of 28-9050 CFU/mL. Validation with 1457 clinical blood cultures showed a negative predictive value of 99.0% compared to blood culture incubation for 5 days. Magnitor showed an improved detection range of 1-67 CFU/mL, allowing for detection of bacteria-supplemented blood cultures after 2-8 h incubation, and Candida albicans-supplemented blood cultures at 16-22 h, 5-15 h faster than blood culture. Removing an aliquot from a blood culture bottle and replacing the bottle into the incubator was shown not to result in contaminating organisms being introduced. CONCLUSIONS: The described method displays excellent breadth and detection for microbial cells and demonstrates the capability of confirming negative blood cultures after an overnight incubation in a blood culture instrument.

4.
Front Psychol ; 10: 1934, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507492

RESUMO

This study explored patterns of change in stress variables (i.e., stressors, appraisals, emotions) encountered by wounded, injured, and sick military veterans in the build up to, during, and following an international sporting competition. The study also examined interactions between psychosocial variables and salivary biomarkers of stress and how these relate to veterans' health, well-being, illness, and performance. 40 Invictus Games (IG) athletes and a control group of 20 military veteran athletes completed questionnaires at seven time points over a 12-week period. Furthermore, participants provided morning and evening saliva samples at four time points to measure cortisol and secretory immunoglobulin A. Multilevel growth curve analyses revealed significant changes in growth trajectories of stress-related variables. For example, team and culture stressors and anger and dejection emotions significantly increased in the build up to competition, whilst challenge appraisals and excitement and happiness emotions significantly decreased over the same time-frame. A number of the stress related variables also predicted performance, well-being, and mental health. Specifically, organizational stressors and threat appraisals were found to negatively relate to performance, well-being, and mental health. Furthermore, whilst challenge appraisals and problem focused coping positively related to veterans' well-being, adopting emotion-focused and avoidance coping strategies negatively predicted well-being and mental health. Turning to emotions, experiencing anger, anxiety, and dejection negatively related to mental health, well-being and performance; whereas happiness and excitement displayed a positive relationship with these outcomes. The findings also highlighted that organizational stressor intensity was positively related to cortisol exposure at competition. To conclude, this study not only provides a novel, longitudinal, interdisciplinary insight into psychological and biological markers of the stress response as it relates to the performance, health, and well-being of military veterans, but also further contributes to theoretical understanding on the transactional nature of stress. Moreover, the findings significantly contribute to practice regarding how best to support this unique population in adaptively responding to and engaging with competitive sport.

5.
Br J Health Psychol ; 24(2): 282-297, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30637952

RESUMO

OBJECTIVES: To assess the interplay of prior life stress and characteristics of resilience in determining how children cope with potentially stressful situations, using a two-phase study that triangulates parent-child dyadic interview data with subsequent experience of an acute laboratory stressor in 7-11-year-olds. METHODS: Participants (n = 34) were designated as being in one of four groups based on high/low levels of prior stress experience and high/low resilience ratings assessed during at-home interviews and from questionnaires measuring recent life events, hassles, and trait coping. During a subsequent laboratory stress protocol, salivary cortisol and heart rate were monitored, and a verbal subjective report was provided. RESULTS: Salivary cortisol showed a significant increase in anticipation of the stress test, heart rate increased during the test, and children self-reported the task as stressful. Males displayed higher levels of cortisol than females in the anticipatory period. We observed no increase in salivary cortisol in response to the stress testing phase. Using the stress/resilience categorization, children with a higher level of resilience were differentiated by cortisol level in anticipation of the acute stress experiment based on their level of prior life stress. Highly resilient children with greater experience of prior life stress showed a lower anticipatory cortisol response than highly resilient children with less experience of prior life stress. CONCLUSIONS: This study highlights the relevance of contextual factors, such as prior stress experience and resilience, in physiological response to the anticipation of acute stress and has implications for understanding how children cope with stressful experiences. Statement of contribution What is already known on this subject? An adaptation to the stress testing paradigm, the Bath Experimental Stress Test for Children (BEST-C) was found to reliably induce a salivary cortisol response in young children, suggesting that peer matching the audience was an effective modification to laboratory social stress testing. Recent work focusing on early life adversity has seen the emergence of prior stress experience and resilience as key factors in the examination of acute stress responses. However, much of the research regarding the impact of childhood stress is ambiguous; some research suggests that if children have experienced prior stressful life events this will enact a positive effect on stress responses and lead to resilience, and other research suggested that it will have a compounding negative effect. What does the study add? Findings provide support for the capacity of the BEST-C to induce an anticipation stress response in children. Contextual factors e.g., prior stress experience and resilience are key for understanding stress responses. Resilient children with more experience of stress show lower cortisol than those with less stress experience.


Assuntos
Adaptação Psicológica/fisiologia , Frequência Cardíaca/fisiologia , Hidrocortisona/metabolismo , Resiliência Psicológica , Comportamento Social , Estresse Psicológico/fisiopatologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Entrevistas como Assunto , Masculino , Grupo Associado , Saliva/metabolismo , Fatores Sexuais , Estresse Psicológico/metabolismo , Estresse Psicológico/psicologia , Inquéritos e Questionários
7.
Front Immunol ; 9: 648, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29713319

RESUMO

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.


Assuntos
Envelhecimento/fisiologia , Exercício Físico/fisiologia , Sistema Imunitário , Imunossupressão , Neoplasias/imunologia , Infecções Respiratórias/imunologia , Humanos , Imunidade nas Mucosas , Imunização , Vigilância Imunológica
8.
Physiol Behav ; 194: 191-198, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29763678

RESUMO

Dendritic cells (DCs) are important sentinel cells of the immune system responsible for presenting antigen to T cells. Exercise is known to cause an acute and transient increase in the frequency of DCs in the bloodstream in humans, yet there are contradictory findings in the literature regarding the phenotypic composition of DCs mobilised during exercise, which may have implications for immune regulation and health. Accordingly, we sought to investigate the composition of DC sub-populations mobilised in response to acute aerobic exercise. Nine healthy males (age, 21.9 ±â€¯3.6 years; height, 177.8 ±â€¯5.4 cm; body mass, 78.9 ±â€¯10.8 kg; body mass index, 24.9 ±â€¯3.3 kg·m2; V̇O2 MAX, 41.5 ±â€¯5.1 mL·kg·min-1) cycled for 20 min at 80% V̇O2 MAX. Blood was sampled at baseline, during the final minute of exercise and 30 min later. Using flow cytometry, total DCs were defined as Lineage- (CD3, CD19, CD20, CD14, CD56) HLA-DR+ and subsequently identified as plasmacytoid DCs (CD303+) and myeloid DCs (CD303-). Myeloid DCs were analysed for expression of CD1c and CD141 to yield four sub-populations; CD1c-CD141+; CD1c+CD141+; CD1c+CD141- and CD1c-CD141-. Expression of CD205 was also analysed on all DC sub-populations to identify DCs capable of recognising apoptotic and necrotic cells. Total DCs increased by 150% during exercise (F(1,10) = 60; p < 0.05, η2 = 0.9). Plasmacytoid DCs mobilised to a greater magnitude than myeloid DCs (195 ±â€¯131% vs. 131 ±â€¯100%; p < 0.05). Among myeloid DCs, CD1c-CD141- cells showed the largest exercise-induced mobilisation (167 ±â€¯122%), with a stepwise pattern observed among the remaining sub-populations: CD1c+CD141- (79 ±â€¯50%), followed by CD1c+CD141+ (44 ±â€¯41%), with the smallest response shown by CD1c-CD141+ cells (23 ±â€¯54%) (p < 0.05). Among myeloid DCs, CD205- cells were the most exercise responsive. All DC subsets returned to resting levels within 30 min of exercise cessation. These results show that there is a preferential mobilisation of plasmacytoid DCs during exercise. Given the functional repertoire of plasmacytoid DCs, which includes the production of interferons against viral and bacterial pathogens, these findings indicate that exercise may augment immune-surveillance by preferentially mobilising effector cells; these findings have general implications for the promotion of exercise for health, and specifically for the optimisation of DC harvest for cancer immunotherapy.


Assuntos
Células Dendríticas/fisiologia , Exercício Físico/fisiologia , Antígenos CD/metabolismo , Moléculas de Adesão Celular/metabolismo , Células Dendríticas/citologia , Humanos , Lectinas Tipo C/metabolismo , Masculino , Antígenos de Histocompatibilidade Menor/metabolismo , Receptores de Superfície Celular/metabolismo , Adulto Jovem
9.
Front Immunol ; 9: 169, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29479350

RESUMO

Ageing, like obesity, is often associated with alterations in metabolic and inflammatory processes resulting in morbidity from diseases characterised by poor metabolic control, insulin insensitivity, and inflammation. Ageing populations also exhibit a decline in immune competence referred to as immunosenescence, which contributes to, or might be driven by chronic, low-grade inflammation termed "inflammageing". In recent years, animal and human studies have started to uncover a role for immune cells within the stromal fraction of adipose tissue in driving the health complications that come with obesity, but relatively little work has been conducted in the context of immunometabolic adipose function in ageing. It is now clear that aberrant immune function within adipose tissue in obesity-including an accumulation of pro-inflammatory immune cell populations-plays a major role in the development of systemic chronic, low-grade inflammation, and limiting the function of adipocytes leading to an impaired fat handling capacity. As a consequence, these changes increase the chance of multiorgan dysfunction and disease onset. Considering the important role of the immune system in obesity-associated metabolic and inflammatory diseases, it is critically important to further understand the interplay between immunological processes and adipose tissue function, establishing whether this interaction contributes to age-associated immunometabolic dysfunction and inflammation. Therefore, the aim of this article is to summarise how the interaction between adipose tissue and the immune system changes with ageing, likely contributing to the age-associated increase in inflammatory activity and loss of metabolic control. To understand the potential mechanisms involved, parallels will be drawn to the current knowledge derived from investigations in obesity. We also highlight gaps in research and propose potential future directions based on the current evidence.


Assuntos
Tecido Adiposo/imunologia , Tecido Adiposo/metabolismo , Envelhecimento , Obesidade/imunologia , Obesidade/metabolismo , Adipócitos/imunologia , Adipócitos/metabolismo , Tecido Adiposo/fisiopatologia , Animais , Modelos Animais de Doenças , Humanos , Imunossenescência , Inflamação , Camundongos
11.
Oxid Med Cell Longev ; 2017: 4234765, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28751932

RESUMO

Moderate intensity aerobic exercise training or regular physical activity is beneficial for immune function. For example, some evidence shows that individuals with an active lifestyle exhibit stronger immune responses to vaccination compared to those who are inactive. Encouragingly, poor vaccine responses, which are characteristic of an ageing immune system, can be improved by single or repeated bouts of exercise. In addition, exercise-induced lymphocytosis, and the subsequent lymphocytopenia, is thought to facilitate immune surveillance, whereby lymphocytes search tissues for antigens derived from viruses, bacteria, or malignant transformation. Aerobic exercise training is anti-inflammatory and is linked to lower morbidity and mortality from diseases with infectious, immunological, and inflammatory aetiologies, including cancer. These observations have led to the view that aerobic exercise training might counter the age-associated decline in immune function, referred to as immunosenescence. This article summarises the aspects of immune function that are sensitive to exercise-induced change, highlighting the observations which have stimulated the idea that aerobic exercise training could prevent, limit, or delay immunosenescence, perhaps even restoring aged immune profiles. These potential exercise-induced anti-immunosenescence effects might contribute to the mechanisms by which active lifestyles reduce the risk of developing cancer and perhaps benefit patients undergoing cancer therapy.


Assuntos
Senescência Celular/imunologia , Neoplasias/imunologia , Neoplasias/terapia , Linfócitos T/imunologia , Animais , Humanos , Neoplasias/patologia , Fatores de Risco , Linfócitos T/patologia
12.
J Aging Phys Act ; 25(4): 559-569, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28181836

RESUMO

To examine whether the volume of previous exercise training in older athletes influences inflammatory, redox, and hormonal profiles, 40 trained marathon runners were divided into higher-volume (HVG, ∼480 min/week) and lower-volume groups (LVG, ∼240 min/week). Plasma inflammatory proteins, redox biomarkers, salivary testosterone, and cortisol were assessed at restand following two maximal acute exercise bouts. At rest, the LVG exhibited higher CRP, higher protein carbonyls, and lower SOD activity compared to the HVG (p's < .05). In response to exercise, TNF-α declined similarly in both groups whereas CRP increased differentially (+60% LVG; +24% HVG; p's < .05). Protein carbonyls decreased and thiols increased similarly in both groups, but SOD declined differentially between groups (-14% LVG; -20% HVG; p's < .05). Salivary testosterone decreased similarly in both groups, whereas cortisol did not change. A higher volume of training is associated with favorable inflammatory and redox profiles at rest, perhaps mediated by small inflammatory responses to acute exercise.


Assuntos
Envelhecimento/fisiologia , Proteína C-Reativa/análise , Exercício Físico/fisiologia , Hidrocortisona/sangue , Testosterona/análise , Fator de Necrose Tumoral alfa/sangue , Idoso , Atletas , Biomarcadores/análise , Biomarcadores/sangue , Teste de Esforço/métodos , Feminino , Humanos , Masculino , Resistência Física , Treinamento de Resistência/métodos , Corrida/fisiologia , Estatística como Assunto
13.
Brain Sci ; 6(4)2016 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-27792175

RESUMO

It has been known that both estrogen (E2) and nitric oxide (NO) are critical for proper cardiovascular system (CVS) function. It has also been demonstrated that E2 acts as an upstream effector in the nitric oxide (NO) pathway. Results from this study indicate that the use of a nitric oxide synthase (NOS) inhibitor (NOSI) which targets specifically neuronal NOS (nNOS or NOS1), proadifen hydrochloride, caused a significant depression of fish heart rates (HR) accompanied by increased arrhythmic behavior. However, none of these phenotypes were evident with either the inhibition of endothelial NOS (eNOS) or inducible NOS (iNOS) isoforms. These cardiac arrhythmias could also be mimicked by inhibition of E2 synthesis with the aromatase inhibitor (AI), 4-OH-A, in a manner similar to that of nNOSI. In both scenarios, by using an NO donor (DETA-NO) in either NO + nNOSI or E2 + AI co-treatments, fish could be significantly rescued from decreased HR and increased arrhythmias. However, the addition of an NOS inhibitor (L-NAME) to the E2 + AI co-treatment fish prevented the rescue of low heart rates and arrhythmias, which strongly implicates the NO pathway as a downstream E2 targeted molecule for the maintenance of healthy cardiomyocyte contractile conditions in the developing zebrafish. Cardiac arrhythmias could be mimicked by the S-nitrosylation pathway inhibitor DTT (1,4-dithiothreitol) but not by ODQ (1H-[1-3]oxadiazolo[4,3-a]quinoxalin-1-one), the inhibitor of the NO receptor molecule sGC in the cGMP-dependent pathway. In both the nNOSI and AI-induced arrhythmic conditions, 100% of the fish expressed the phenotype, but could be rapidly rescued with maximum survival by a washout with dantrolene, a ryanodine Ca2+ channel receptor blocker, compared to the time it took for rescue using a control salt solution. In addition, of the three NOS isoforms, eNOS was the one most implicated in the maintenance of an intact developing fish vascular system. In conclusion, results from this study have shown that nNOS is the prominent isoform that is responsible, in part, for maintaining normal heart rates and prevention of arrhythmias in the developing zebrafish heart failure model. These phenomena are related to the upstream stimulatory regulation by E2. On the other hand, eNOS has a minimal effect and iNOS has little to no influence on this phenomenon. Data also suggests that nNOS acts on the zebrafish cardiomyocytes through the S-nitrosylation pathway to influence the SR ryanidine Ca2+ channels in the excitation-coupling phenomena. In contrast, eNOS is the prominent isoform that influences blood vessel development in this model.

14.
Trials ; 17: 381, 2016 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-27484001

RESUMO

BACKGROUND: Muscles get smaller and weaker as we age and become more vulnerable to atrophy when physical activity is reduced or removed. This research is designed to investigate the potentially protective effects of two separate exercise strategies against loss in skeletal muscle function and size, and other key indices of health, following 14 days of reduced physical activity in older men. METHODS: Three groups of 10 older men (aged 65-80 years) will undertake 2 weeks of reduced activity by decreasing daily steps from more than 3500 to less than 1500 (using pedometers to record step count). Two of the three groups will then undertake additional exercise interventions, either: 4 weeks of progressive resistance training prior to the step-reduction intervention (PT-group), or home-based 'exercise snacking' three times per day during the step-reduction intervention (ES-group). The third group undertaking only the step-reduction intervention (control) will provide a comparison against which to assess the effectiveness of the protective exercise strategies. Pre and post step-reduction assessments of muscle function, standing balance, anthropometry and muscle architecture will be taken. Pre and post step-reduction in postprandial metabolic control, resting systemic inflammation, adipose inflammation, oxidative stress, immune function, sleep quality, dietary habits, and quality of life will be measured. The stress response to exercise, and signalling protein and gene expression for muscle protein synthesis and breakdown following an acute bout of exercise will also be assessed pre and post step-reduction. Rates of muscle protein synthesis and adipose triglyceride turnover during the step-reduction intervention will be measured using stable isotope methodology. All participants will then undertake 2 weeks of supervised resistance training with the aim of regaining any deficit from baseline in muscle function and size. DISCUSSION: This study aims to identify exercise strategies that could be implemented to protect against loss of muscle power during 2 weeks of reduced activity in older men, and to improve understanding of the way in which a short-term reduction in physical activity impacts upon muscle function and health. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02495727 (Initial registration: 25 June 2015).


Assuntos
Envelhecimento , Exercício Físico , Serviços de Assistência Domiciliar , Músculo Esquelético/fisiopatologia , Treinamento de Resistência , Sarcopenia/prevenção & controle , Comportamento Sedentário , Absorciometria de Fóton , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Protocolos Clínicos , Inglaterra , Humanos , Masculino , Contração Muscular , Proteínas Musculares/biossíntese , Força Muscular , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/metabolismo , Equilíbrio Postural , Proteólise , Recuperação de Função Fisiológica , Projetos de Pesquisa , Treinamento de Resistência/efeitos adversos , Sarcopenia/diagnóstico por imagem , Sarcopenia/metabolismo , Sarcopenia/fisiopatologia , Fatores Sexuais , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Ultrassonografia
15.
Trials ; 17(1): 284, 2016 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-27278276

RESUMO

BACKGROUND: Spinal cord injury (SCI) creates a complex pathology that can lead to an increase in sedentary behaviours and deleterious changes in body composition. Consequently, individuals with SCI are at increased risk of developing cardiovascular disease and type-2 diabetes mellitus. While the role of physical activity on the reduction of chronic disease risk is well documented in non-disabled individuals the evidence is less conclusive for persons with SCI. The aim of this methodological paper is to outline the design of a study that will assess the role of a home-based exercise intervention on biomarkers of metabolic and cardiovascular health in persons with SCI: the HOMEX-SCI study. METHODS/DESIGN: Eligible participants will be inactive (physical activity level ≤1.60) individuals, with a chronic (more than 1 year) spinal cord lesion between the second thoracic and the fifth lumbar vertebrae, and aged between 18 and 65 years. Following baseline laboratory testing and lifestyle monitoring, participants will be randomly allocated to a control (CON) group or a 6-week home-based exercise intervention (INT) group. The INT consists of 45 minutes of moderate-intensity (60-65 % peak oxygen uptake) arm-crank exercise four times per week. Participants assigned to the CON group will be asked to maintain their normal lifestyle. The main outcomes of this study (biomarkers of metabolic and cardiovascular health) are obtained from venous blood samples, collected in the fasted and postprandial state. Eight other measurement categories will be assessed: (1) body composition, (2) physical activity, (3) energy intake, (4) measures of health and wellbeing, (5) resting metabolic rate, heart rate and blood pressure, (6) aerobic capacity, (7) immune function, and (8) adipose tissue gene expression. DISCUSSION: This study will explore the feasibility of home-based moderate-intensity exercise and ascertain its impact on metabolic and cardiovascular health in comparison to a lifestyle maintenance CON group. Findings from this study may help to inform new evidence-based physical activity guidelines and also help to elucidate the physiological mechanisms whereby exercise might exert beneficial effects in persons with chronic SCI. The results will also act as a scientific platform for further intervention studies in other diverse and at-risk populations. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number: ISRCTN57096451 . Registered on 11 July 2014.


Assuntos
Protocolos Clínicos , Terapia por Exercício , Traumatismos da Medula Espinal/reabilitação , Tecido Adiposo/metabolismo , Adolescente , Adulto , Idoso , Composição Corporal , Doença Crônica , Metabolismo Energético , Humanos , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Consumo de Oxigênio , Tamanho da Amostra , Traumatismos da Medula Espinal/metabolismo , Adulto Jovem
16.
17.
Biogerontology ; 17(3): 581-602, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27023222

RESUMO

The age-associated decline in immune function, referred to as immunosenescence, is well characterised within the adaptive immune system, and in particular, among T cells. Hallmarks of immunosenescence measured in the T cell pool, include low numbers and proportions of naïve cells, high numbers and proportions of late-stage differentiated effector memory cells, poor proliferative responses to mitogens, and a CD4:CD8 ratio <1.0. These changes are largely driven by infection with Cytomegalovirus, which has been directly linked with increased inflammatory activity, poor responses to vaccination, frailty, accelerated cognitive decline, and early mortality. It has been suggested however, that exercise might exert an anti-immunosenescence effect, perhaps delaying the onset of immunological ageing or even rejuvenating aged immune profiles. This theory has been developed on the basis of evidence that exercise is a powerful stimulus of immune function. For example, in vivo antibody responses to novel antigens can be improved with just minutes of exercise undertaken at the time of vaccination. Further, lymphocyte immune-surveillance, whereby cells search tissues for antigens derived from viruses, bacteria, or malignant transformation, is thought to be facilitated by the transient lymphocytosis and subsequent lymphocytopenia induced by exercise bouts. Moreover, some forms of exercise are anti-inflammatory, and if repeated regularly over the lifespan, there is a lower morbidity and mortality from diseases with an immunological and inflammatory aetiology. The aim of this article is to discuss recent theories for how exercise might influence T cell immunosenescence, exploring themes in the context of hotly debated issues in immunology.


Assuntos
Exercício Físico , Imunossenescência/imunologia , Esforço Físico/imunologia , Sarcopenia/imunologia , Sarcopenia/prevenção & controle , Linfócitos T/imunologia , Medicina Baseada em Evidências , Terapia por Exercício/normas , Humanos , Imunidade Inata/imunologia , Modelos Imunológicos , Resultado do Tratamento
18.
Free Radic Res ; 50(4): 375-84, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26873473

RESUMO

Exercise of sufficient intensity and duration can cause acute oxidative stress. Plasma protein carbonyl (PC) moieties are abundant, chemically stable, and easily detectable markers of oxidative stress that are widely used for the interpretation of exercise-induced changes in redox balance. Despite many studies reporting acute increases in plasma PC concentration in response to exercise, some studies, including those from our own laboratory have shown decreases. This review will discuss the differences between studies reporting increases, decreases, and no change in plasma PC concentration following exercise in humans; highlighting participant physiology (i.e. training status) and study design (i.e. intensity, duration, and novelty of the exercise bout) as the main factors driving the direction of the PC response to exercise. The role of the 20S proteasome system is proposed as a possible mechanism mediating the clearance of plasma PC following exercise. Resting and exercise-induced differences in plasma protein composition and balance between tissues are also discussed. We suggest that exercise may stimulate the clearance of plasma PC present at baseline, whereas simultaneously increasing reactive oxygen species production that facilitates the formation of new PC groups. The balance between these two processes likely explains why some studies have reported no change or even decreases in plasma PC level post-exercise when other biomarkers of oxidative stress (e.g. markers of lipid peroxidation) were elevated. Future studies should determine factors that influence the balance between PC clearance and formation following acute exercise.


Assuntos
Proteínas Sanguíneas/metabolismo , Exercício Físico , Carbonilação Proteica , Espécies Reativas de Oxigênio/sangue , Descanso/fisiologia , Biomarcadores/sangue , Feminino , Humanos , Peroxidação de Lipídeos/fisiologia , Masculino , Especificidade de Órgãos , Estresse Oxidativo , Esforço Físico , Complexo de Endopeptidases do Proteassoma/metabolismo , Estabilidade Proteica , Proteólise
19.
Med Sci Sports Exerc ; 48(7): 1285-93, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26918560

RESUMO

PURPOSE: This study investigated whether natural killer (NK) cells and CD8+ T cells expressing cutaneous lymphocyte antigen (CLA)-a homing molecule for endothelial cell leukocyte adhesion molecule 1, which enables transmigration to the skin-are selectively mobilized in response to acute exercise. METHODS: Nine healthy men (mean ± SD age: 22.1 ± 3.4 yr) completed two exercise sessions: high-intensity continuous cycling ("continuous exercise" at 80% V˙O2max for 20 min) and low-volume high-intensity interval exercise (at 90% V˙O2max 10 × 1 min repetitions with 1 min recovery intervals). Blood was collected before, immediately and 30 min postexercise for cryopreservation of peripheral blood mononuclear cells. CLA+ and CLA- cells were quantified within NK subpopulations (CD56 "regulatory" and CD56 "cytotoxic" cells) as well as the following CD8+ T cell subpopulations: naive ("NA"; CD45RA+ CCR7+), central memory ("CM"; CD45RA- CCR7+), effector-memory ("EM"; CD45RA- CCR7-), and CD45RA-expressing effector-memory cells ("EMRA"; CD45RA+ CCR7-). RESULTS: CLA+ NK cells and CD8+ memory T cells increased in response to both exercise bouts, but, overall, their numerical contribution to the exercise lymphocytosis was inferior to CLA- cells, which increased to a much greater extent during exercise. Tellingly, the most exercise-responsive cells-effector memory CD8+ cells and CD56 cells-were CLA-. CONCLUSIONS: A small subset of CLA+ lymphocytes are mobilized into blood during acute intensive exercise, but CLA+ cells are not major contributors to exercise lymphocytosis, thus providing preliminary evidence that the skin is not a major origin, or homing destination, of exercise-sensitive lymphocytes.


Assuntos
Linfócitos T CD8-Positivos/citologia , Exercício Físico/fisiologia , Treinamento Intervalado de Alta Intensidade , Células Matadoras Naturais/citologia , Pele/imunologia , Adulto , Antígenos de Diferenciação de Linfócitos T/metabolismo , Movimento Celular , Humanos , Masculino , Glicoproteínas de Membrana/metabolismo , Adulto Jovem
20.
Toxics ; 4(4)2016 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-29051426

RESUMO

Nitric oxide (NO) has been shown to affect motor function. Specifically, NO has been shown to act through regulation of dopamine (DA) release, transporter function, and the elicitation of neuroprotection/neurodegeneration of neurons. Recently, zebrafish have been proposed to be a new model for the study of various types of motor dysfunctions, since neurotoxin damage to their nigrostriatal-like neurons exhibit motor anomalies similar to those of mammalian models and human patients. Results from this study demonstrate that when NO synthesis is inhibited in zebrafish, using a neuronal NO synthase inhibitor (nNOSI), a condition called 'listless' occurs, where the fish lack swimming abilities, are rigid, and have difficulty maintaining balance. Additionally, co-treatment with either NO or estrogen (E2), an upstream regulator of NO synthase, can rescue fish from the 'listless' phenotype caused by exposure to the neurotoxin 6-hydroxydopamine (6 OHDA). In turn, NO deprived zebrafish were rescued from the 'listless' phenotype when co-treated with L-DOPA, a precursor to DA. Interestingly, the longer fish are exposed to a 6 OHDA + nNOSI co-treatment, the slower the recovery after washout, compared to a single treatment of each. Most significantly, NO involvement in the motor homeostasis of the embryonic zebrafish was shown to be expressed through the NO-cGMP-dependent pathway, and response to nNOSI treatments is developmentally regulated. In conclusion, these results indicate that there is a link between E2, NO, and DA systems that regulate motor functions in the embryonic zebrafish.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA