Exercise in sickle cell anemia: effect on inflammatory and vasoactive mediators

Effect of a Physical Exercise Program on the Inflammatory Response, Cardiac Functions, Functional Capacity, and Quality of Life in Patients with Sickle Cell Disease

INTRODUCTION

The beneficial effects of physical exercise on functional capacity and inflammatory response are well-known in cardiovascular diseases; however, studies on sickle cell disease (SCD) are limited. It was hypothesized that physical exercise may exert a favorable effect on the inflammatory response of SCD patients, contributing to an improved quality of life. This study aimed to evaluate the effect of a regular physical exercise program on the anti-inflammatory responses in SCD patients.

METHODS

A non-randomized clinical trial was conducted in adult SCD patients. The patients were divided into two groups: 1-Exercise Group, which received a physical exercise program three times a week for 8 weeks, and; 2-Control Group, with routine physical activities. All patients underwent the following procedures initially and after eight weeks of protocol: clinical evaluation, physical evaluation, laboratory evaluation, quality of life evaluation, and echocardiographic evaluation.

STATISTICAL ANALYSIS

Comparisons between groups were made using Student's t-test, Mann-Whitney test, chi-square test, or Fisher's exact test. Spearman's correlation coefficient was calculated. The significance level was set at p < 0.05.

RESULTS

There was no significant difference in inflammatory response between the Control and Exercise Groups. The Exercise Group showed an improvement in peak VO₂ values (p < 0.001), an increase in the distance walked (p < 0.001), an improvement in the limitation domain due to the physical aspects of the 36-Item Short Form Health Survey (SF-36) quality of life questionnaire (p = 0.022), and an increase in physical activity related to leisure (p < 0.001) and walking (p = 0.024) in the International Physical Activity Questionnaire (IPAQ). There was a negative correlation between IL-6 values and distance walked on the treadmill (correlation coefficient -0.444, p = 0.020) and the estimated peak VO₂ values (correlation coefficient -0.480; p = 0.013) in SCD patients in both groups.

CONCLUSIONS

The aerobic exercise program did not change the inflammatory response profile of SCD patients, nor did it show unfavorable effects on the parameters evaluated, and patients with lower functional capacity were those with the highest levels of IL-6.

Functional capacity and quality of life in children and adolescents with sickle cell anemia

OBJECTIVE

To evaluate the functional and exercise capacity, lung function, quality of life of children and adolescents with sickle cell anemia (SCA HbSS) and to test the reproducibility of functional capacity tests in this population.

METHOD

Cross-sectional study with volunteers with SCA Hb-SS (SCAG), aged 6-18 years matched in age and gender to the control group (CG) with healthy individuals. Spirometry, 5-repetition sit-to-stand test (5STS-test), modified shuttle test (MST), and Pediatric Quality of Life Questionnaire (PedsQL) were performed. The reproducibility of 5STS-test and MST was evaluated: RESULTS: Forty eight volunteers of SCAG and 48 of CG were evaluated. Lung function of SCAG (FVC: 92 ± 15% pred.; FEV₁ /FVC: 84 ± 8% pred.) was worse than the CG (104 ± 15% pred.; FEV₁ /FVC: 90 ± 6% pred.) p < 0.05. SCAG had worse functional capacity registered by distance walked: 576 m (515-672 m) and 5STS-test: 8 s (7.4-8.9 s) compared with the CG who showed distance walked: 1010 m (887-1219 m) and 5STS-test: 7 s (7.0-8.1 s), p < 0.001. SCAG had worse quality of life compared to CG, p < 0.05. The reproducibility of MST (ICC 0.99 (0.98-0.99 IC-95%)) and 5STS-test (ICC 0.80 (0.69-0.88) was considered good, p < 0.001.

CONCLUSION

Children and adolescents with sickle cell anemia presented worse capacity to walk or run, and to perform sit-to-stand test when compared with their control peers. Additionally, they have poorer quality of life. The MST and 5STS-test showed good reproducibility to be applied in pediatric individuals with SCA.

Therapist-oriented home rehabilitation for adults with sickle cell anemia: effects on muscle strength, functional capacity, and quality of life

OBJECTIVES

Considering the advances in functional rehabilitation in recent decades, therapist-oriented home rehabilitation (TOHR) has been increasingly used in the field of physical therapy because it increases patient compliance and reduces health system costs. The objective of this study was to investigate the effects of TOHR on functional capacity, muscle strength, and quality of life (QoL) in adults with sickle cell anemia (SCA).

METHODS

Forty adults with SCA underwent manually guided TOHR for 12 weeks. Before and at the end of training, the following variables were assessed in the participants: distance covered in the 6-min walk test (6MWD); maximal inspiratory pressure (MIP); maximal expiratory pressure (MEP); handgrip strength (HGS); quadriceps strength (QS); and QoL using the Short Form-36 physical component summary (SF-36_PCS) and the Short Form-36 mental component summary (SF-36_MCS).

RESULTS

After TOHR, significant increases were observed in the mean values for the 6MWD, MIP, MEP, HGS, QS, and SF-36_PCS and SF-36_MCS scores. The relative delta between the pre- and post-TOHR 6MWDs correlated significantly with the relative deltas of MIP (r_s = 0.640, p < 0.0001), MEP (r_s = 0.587, p < 0.0001), HGS (r_s = 0.360, p = 0.022), and QS (r_s = 0.351, p = 0.026). When the participants were separated according to their use of hydroxyurea, significant increases were observed in the relative deltas of the 6MWD, MIP and MEP values.

CONCLUSIONS

This study shows that TOHR can potentially increase functional capacity, muscle strength, and QoL in adults with SCA. Furthermore, there appears to be a relationship between 6MWD gains and muscle strength gains with TOHR.Trial registration: ClinicalTrials.gov identifier: NCT04705792.

Cardiovascular benefits of a home-based exercise program in patients with sickle cell disease

BACKGROUND

Physical inactivity is an important risk factor for cardiovascular disease. The benefits of exercise in patients with chronic diseases, including cardiovascular diseases, are well established. For patients with sickle cell disease, medical recommendation was to avoid physical exercise for fear of triggering painful crises or increasing the impairment of the cardiopulmonary function. Only recently, studies have shown safety in exercise programs for this population. Despite that, there is no report that assess the effects of physical exercise on cardiac parameters in patients with sickle cell disease.

OBJECTIVE

This study aimed to evaluate the impact of regular physical exercise (a home-based program) on cardiovascular function in patients with sickle cell disease.

DESIGN

A quasi-randomized prospective controlled trial.

SETTING

During the years 2015 and 2016, we started recruiting among adult patients treated at a Brazilian Center for Patients with Sickle Cell Disease to participate in a study involving a home exercise program. The experimental (exercise) and control groups were submitted to clinical evaluation and cardiovascular tests before and after the intervention. Analysis of variance was applied to compare groups, considering time and group factors.

PARTICIPANTS

Twenty-seven adult outpatients with a sickle cell disease diagnosis.

INTERVENTIONS

Exercise group (N = 14): a regular home-based aerobic exercise program, three to five times per week not exceeding give times per week, for eight weeks; no prescription for the control group (N = 13).

MAIN OUTCOME MEASURES

Echocardiographic and treadmill test parameters.

RESULTS

The exercise group showed significant improvement in cardiovascular tests, demonstrated by increased distance traveled on a treadmill (p<0.01), increased ejection fraction (p < 0.01) and improvement of diastolic function assessed by mitral tissue Doppler E' wave on echocardiography (p = 0.04). None of the patients presented a sickle cell crisis or worsening of symptoms during the exercise program.

CONCLUSION

The selected home-based exercise program is safe, feasible, and promotes a favorable impact on functional capacity and cardiovascular function in sickle cell disease patients.

Beneficial effects of endurance exercise training on skeletal muscle microvasculature in sickle cell disease patients

Sickle cell disease (SCD) is a genetic hemoglobinopathy leading to 2 major clinical manifestations: severe chronic hemolytic anemia and iterative vaso-occlusive crises. SCD is also accompanied by profound muscle microvascular remodeling. The beneficial effects of endurance training on microvasculature are widely known. The aim of this study was to evaluate the effects of an endurance training program on microvasculature of skeletal muscle in SCD patients. A biopsy of the vastus lateralis muscle and submaximal incremental exercise was performed before and after the training period. Of the 40 randomized SCD patients, complete data sets from 32 patients were obtained. The training group (n = 15) followed a personalized moderate-intensity endurance training program, while the nontraining (n = 17) group maintained a normal lifestyle. Training consisted of three 40-minute cycle ergometer exercise sessions per week for 8 weeks. Histological analysis highlighted microvascular benefits in the training SCD patients compared with nontraining patients, including increases in capillary density (P = .003), number of capillaries around a fiber (P = .015), and functional exchange surface (P < .0001). Conversely, no significant between-group difference was found in the morphology of capillaries. Indexes of physical ability also improved in the training patients. The moderate-intensity endurance exercise training program improved the muscle capillary network and partly reversed the microvascular defects commonly observed in skeletal muscle of SCD patients. This trial was registered at www.clinicaltrials.gov as #NCT02571088.

Blood Rheology: Key Parameters, Impact on Blood Flow, Role in Sickle Cell Disease and Effects of Exercise

Blood viscosity is an important determinant of local flow characteristics, which exhibits shear thinning behavior: it decreases exponentially with increasing shear rates. Both hematocrit and plasma viscosity influence blood viscosity. The shear thinning property of blood is mainly attributed to red blood cell (RBC) rheological properties. RBC aggregation occurs at low shear rates, and increases blood viscosity and depends on both cellular (RBC aggregability) and plasma factors. Blood flow in the microcirculation is highly dependent on the ability of RBC to deform, but RBC deformability also affects blood flow in the macrocirculation since a loss of deformability causes a rise in blood viscosity. Indeed, any changes in one or several of these parameters may affect blood viscosity differently. Poiseuille's Law predicts that any increase in blood viscosity should cause a rise in vascular resistance. However, blood viscosity, through its effects on wall shear stress, is a key modulator of nitric oxide (NO) production by the endothelial NO-synthase. Indeed, any increase in blood viscosity should promote vasodilation. This is the case in healthy individuals when vascular function is intact and able to adapt to blood rheological strains. However, in sickle cell disease (SCD) vascular function is impaired. In this context, any increase in blood viscosity can promote vaso-occlusive like events. We previously showed that sickle cell patients with high blood viscosity usually have more frequent vaso-occlusive crises than those with low blood viscosity. However, while the deformability of RBC decreases during acute vaso-occlusive events in SCD, patients with the highest RBC deformability at steady-state have a higher risk of developing frequent painful vaso-occlusive crises. This paradox seems to be due to the fact that in SCD RBC with the highest deformability are also the most adherent, which would trigger vaso-occlusion. While acute, intense exercise may increase blood viscosity in healthy individuals, recent works conducted in sickle cell patients have shown that light cycling exercise did not cause dramatic changes in blood rheology. Moreover, regular physical exercise has been shown to decrease blood viscosity in sickle cell mice, which could be beneficial for adequate blood flow and tissue perfusion.

Exercise Testing of Adolescents and Young Adults With Sickle Cell Disease: Perceptual Responses and the Gas Exchange Threshold

For individuals with sickle cell disease (SCD), mild to moderate exercise is advised, but self-regulation of these intensities is difficult. To regulate intensity, one SCD recommendation is to stop exercising at the first perception of fatigue. However, perceived effort and affect (how one feels) are perceptual cues that are commonly used to guide exercise intensity. This study (a) examined perceived effort, affect, and fatigue in relation to metabolic state (gas exchange) in adolescents and young adults (AYAs) with SCD, (b) explored guidelines AYAs use to self-regulate exercise, and (c) compared perceived effort and affect at gas exchange threshold (GET) with healthy counterparts. Twenty-two AYAs with SCD completed an incremental cycle test. Perceived effort, affect, and fatigue were assessed every 2 minutes. A mixed-effects linear model was conducted to model changes in effort, affect, and fatigue across time. Mean scores of effort and affect at GET were compared with published data of healthy counterparts. Participants were queried about self-regulation exercise strategies. Findings indicated that both perceived fatigue and effort at GET was lower than expected. Perceived effort was lower (p < .0001), and perceived affect was significantly higher (p = .0009) than healthy counterparts. Interviews revealed that most participants (95%) do not stop exercising until fatigue is moderate to severe, and many (73%) do not stop until symptoms are severe (chest tightness, blurry vision). Nurses should review guidelines for safe exercise with AYAs with SCD. Exercise training may be beneficial to AYAs with SCD for learning how to interpret bodily responses to exercise to improve self-regulation.

Balancing exercise risk and benefits: lessons learned from sickle cell trait and sickle cell anemia

Development of exercise guidelines for individuals with sickle cell trait (SCT) and sickle cell anemia (SCA) is hampered by the need to weigh the benefits against risks of exercise in these populations. In SCT, concern for exercise collapse associated with sickle cell trait has resulted in controversial screening of student athletes for SCT. In SCA, there exists unsubstantiated concerns that high-intensity exercise may result in pain and other complications. In both, finding the "right dose" of exercise remains a challenge for patients and their providers. Despite assumptions that factors predisposing to adverse events from high-intensity exercise overlap in SCT and SCA, the issues that frame our understanding of exercise-related harms in both are distinct. This review will compare issues that affect the risk-benefit balance of exercise in SCT and SCA through these key questions: (1) What is the evidence that high-intensity exercise is associated with harm? (2) What are the pathophysiologic mechanisms that could predispose to harm? (3) What are the preventive strategies that may reduce risk? and (4) Why do we need to consider the benefits of exercise in this debate? Addressing these knowledge gaps is essential for developing an evidence-based exercise prescription for these patient populations.

Role of Exercise-Induced Oxidative Stress in Sickle Cell Trait and Disease

Sickle cell disease is a class of hemoglobinopathy in humans, which is the most common inherited disease in the world. Although complications of sickle cell disease start from polymerization of red blood cells during its deoxygenating phase, the oxidative stress resulting from the biological processes associated with this disease (ischaemic and hypoxic injuries, hemolysis and inflammation) has been shown to contribute to its pathophysiology. It is widely known that chronic exercise reduces oxidative stress in healthy people, mainly via improvement of antioxidant enzyme efficiency. In addition, recent studies in other diseases, as well as in sickle cell trait carriers and in a mouse model of sickle cell disease, have shown that regular physical activity could decrease oxidative stress. The purpose of this review is to summarize the role of oxidative stress in sickle cell disease and the effects of acute and chronic exercise on the pro-oxidant/antioxidant balance in sickle cell trait and sickle cell disease.

Impaired muscle force production and higher fatigability in a mouse model of sickle cell disease

Skeletal muscle function has been scarcely investigated in sickle cell disease (SCD) so that the corresponding impact of sickle hemoglobin is still a matter of debate. The purpose of this study was to investigate muscle force production and fatigability in SCD and to identify whether exercise intensity could have a modulatory effect. Ten homozygous sickle cell (HbSS), ten control (HbAA) and ten heterozygous (HbAS) mice were submitted to two stimulation protocols (moderate and intense) to assess force production and fatigability. We showed that specific maximal tetanic force was lower in HbSS mice as compared to other groups. At the onset of the stimulation period, peak force was reduced in HbSS and HbAS mice as compared to HbAA mice. Contrary to the moderate protocol, the intense stimulation protocol was associated with a larger decrease in peak force and rate of force development in HbSS mice as compared to HbAA and HbAS mice. These findings provide in vivo evidence of impaired muscle force production and resistance to fatigue in SCD. These changes are independent of muscle mass. Moreover, SCD is associated with muscle fatigability when exercise intensity is high.

Does physical activity increase or decrease the risk of sickle cell disease complications?

Sickle cell disease (SCD) is the most common inherited disease in the world. Red blood cell sickling, blood cell-endothelium adhesion, blood rheology abnormalities, intravascular haemolysis, and increased oxidative stress and inflammation contribute to the pathophysiology of SCD. Because acute intense exercise may alter these pathophysiological mechanisms, physical activity is usually contra-indicated in patients with SCD. However, recent studies in sickle-cell trait carriers and in a SCD mice model show that regular physical activity could decrease oxidative stress and inflammation, limit blood rheology alterations and increase nitric oxide metabolism. Therefore, supervised habitual physical activity may benefit patients with SCD. This article reviews the literature on the effects of acute and chronic exercise on the biological responses and clinical outcomes of patients with SCD.

Coronary artery ectasia in atherosclerotic coronary artery disease, inflammatory disorders, and sickle cell disease

Coronary artery ectasia (CAE) or aneurysm is usually defined as dilation ≥1.5-fold the normal vessel diameter. It has an incidence of 1.4-5.3% and is associated with a wide variety of etiologies-mainly congenital, atherosclerotic, and inflammatory ones. CAE is very common in sickle cell disease, and possibly sickle cell trait, with an incidence of 17.7%. It is likely related to the inflammatory process associated with hemoglobin S. Prognosis depends mainly on the underlying etiology. Atherosclerotic CAE does not carry additional risks compared to atherosclerotic coronary artery disease (ACAD) without ectasia. However, isolated CAE in the absence of ACAD carries an increased risk of myocardial infarction (MI) due to vasospasm, slower coronary blood flow, and thrombosis, typically within the dilated segments. Due to lack of studies and guidelines, management recommendations are based on personal experiences. Therapy should be tailored to each individual case after assessment of severity, history of complications, underlying etiology, and comorbidities. Treatment of underlying condition and avoidance of exacerbating factors are essential. Medical therapy in general may include antiplatelets, β-blockers, angiotensin-converting enzyme inhibitors statins, and dihydropyridine calcium channel blockers. In severe CAE or history of MI, the addition of anticoagulation therapy after assessing bleeding risk may be warranted. In acute MI, the large thrombus burden in the dilated segment makes the percutaneous approach very challenging. Aspiration attempts can result in distal thromboembolization. Survival is better in bypass grafting than with medical therapy. Nonetheless, bypass grafting does not improve survival in atherosclerotic CAE. Depending on the physical characteristics of aneurysm, different surgical approaches can be sought; however, the ideal one is unclear.

The acute phase inflammatory response to maximal exercise testing in children and young adults with sickle cell anaemia

Although individuals with sickle cell anaemia (SCA) have elevated baseline inflammation and endothelial activation, the acute phase response to maximal exercise has not been evaluated among children with SCA. We measured the acute phase response to maximal exercise testing for soluble vascular cell adhesion molecule (sVCAM) as well as interleukin 6 (IL6), total white blood cell (WBC) count, C-reactive protein (CRP) and D-dimer in a cohort of children with SCA and matched controls at baseline, immediately after, and 30, 60 and 120 min following exercise. Despite higher baseline levels of all biomarkers except CRP, the acute phase response from baseline to immediately after exercise was significantly greater in subjects versus controls for CRP (2·1 vs. 0·2 mg/l, P = 0·02) and D-dimer (160 vs. 10 μg/l, P < 0·01) only. Similar between-group trends were observed over time for all biomarkers, including sVCAM, IL6, total WBC, CRP and D-dimer. Lower fitness, defined by peak oxygen consumption (VO2 ), was independently associated with greater acute phase responses to exercise for sVCAM. Our results suggest maximal exercise may not be associated with any greater escalation of endothelial activation or inflammation in SCA and provide preliminary biomarker evidence for the safety of brief, high-intensity physical exertion in children with SCA.

Acute moderate exercise does not further alter the autonomic nervous system activity in patients with sickle cell anemia

A decreased global autonomic nervous system (ANS) activity and increased sympathetic activation in patients with sickle cell anemia (SCA) seem to worsen the clinical severity and could play a role in the pathophysiology of the disease, notably by triggering vaso-occlusive crises. Because exercise challenges the ANS activity in the general population, we sought to determine whether a short (<15 min) and progressive moderate exercise session conducted until the first ventilatory threshold had an effect on the ANS activity of a group of SCA patients and a group of healthy individuals (CONT group). Temporal and spectral analyses of the nocturnal heart rate variability were performed before and on the 3 nights following the exercise session. Standard deviation of all normal RR intervals (SDNN), total power, low frequencies (LF) and high frequencies powers (HF) were lower but LF/HF was higher in SCA patients than in the CONT group. Moderate exercise did not modify ANS activity in both groups. In addition, no adverse clinical events occurred during the entire protocol. These results imply that this kind of short and moderate exercise is not detrimental for SCA patients.

Cytokines in chronically critically ill patients after activity and rest

Inflammation, a common problem for patients in the intensive care unit (ICU), frequently is associated with serious and prolonged critical illnesses. To date, no study has examined whether physical activity influences inflammatory factors in critically ill adults. The objectives of this study were to (a) examine the relationships between type and duration of physical activity and serum levels of interleukin 6 (IL-6), a proinflammatory cytokine; IL-10, an anti-inflammatory cytokine; and their ratio and (b) determine if there are associations between cytokines or their ratio and activity or outcomes. This descriptive feasibility study investigated the approaches to measuring levels of physical activity and its relationship to serum levels of IL-6 and IL-10 and the ratio between them in patients with prolonged mechanical ventilation during periods of activity and rest. Measurements included serum IL-6 and IL-10 levels, direct observation and actigraphy, and prospective chart review. Ten critically ill patients who were mechanically ventilated for an average of 10 days in a large, urban, teaching hospital were enrolled. The average ratio of IL-6 to IL-10 improved after an average of 14.7 min of passive physical activity, typically multiple in-bed turns associated with hygiene. IL-6, IL-10, and their ratio were not associated with patient outcomes of weaning success or length of stay. High levels of IL-6 were associated with mortality. Cytokine balance may be improved by low levels of activity among patients with prolonged critical illness. The pattern of cytokines produced after activity may improve patients' recovery from prolonged critical illness and mechanical ventilation.

Inactivity and Inflammation in the Critically Ill Patient

Bed rest is a commonly prescribed activity restriction among patients in the ICU. Although bed rest may promote rest, recovery and safety, inactivity related to bed rest also may lead to complications and adverse outcomes. The biological mechanisms that lead to immediate and long-term sequelae from bed rest have not been elucidated. It may be the inflammatory factors common to critical illness combined with bed rest lead to a positive feedback loop, contributing to inflammatory disequilibrium. This disequilibrium has a profound affect on muscles. Muscle decay has serious and long-term adverse outcomes on survivors of critical illness. Mobility therapy may improve inflammatory disequilibrium and preserve muscles, leading to improved functional outcome. Investigations in the laboratory, in healthy people and among patients with systemic inflammatory disease, suggest that activity does not exacerbate inflammation. Clinically, exercise is beneficial to patients with various chronic inflammatory diseases. Further study is needed to best understand the role, duration, and frequency of activity in promoting recovery for critically ill patients.

Oxidative stress and inflammation in iron-overloaded patients with beta-thalassaemia or sickle cell disease

Blood transfusion therapy is life-saving for patients with beta-thalassaemia and sickle cell disease (SCD), but often results in severe iron overload. This pilot study examined whether the biomarkers of tissue injury or inflammation differ in these two diseases. Plasma malondialdehyde (MDA) was significantly increased 1.8-fold in thalassaemia relative to control patients. In contrast, MDA in SCD was not significantly different from controls. In multivariate analysis, the strongest predictors of elevated MDA were liver iron concentration (P < 0.001) and specific diagnosis (P = 0.019). A significant 2-fold elevation of non-transferrin bound iron (NTBI) was observed in thalassaemia relative to SCD. NTBI was not a significant predictor of high MDA in multivariate analysis. SCD patients showed a significant 2.2-fold elevation of the inflammatory marker interleukin (IL)-6 relative to controls, and a 3.6- and 1.7-fold increase in IL-5 and IL-10 relative to thalassaemia. Although alpha-tocopherol was significantly decreased by at least 32% in both thalassaemia and SCD, indicating ongoing oxidant stress and antioxidant consumption, gamma-tocopherol, a nitric oxide-selective antioxidant, was increased 36% in SCD relative to thalassaemia. These results demonstrate that thalassaemia patients have increased MDA and circulating NTBI relative to SCD patients and lower levels of some cytokines and gamma-tocopherol. This supports the hypothesis that the biology of SCD may show increased inflammation and increased levels of protective antioxidants compared with thalassaemia.

Inactivity and Inflammation

Muscle dysfunction leads to activity intolerance, prolonged hospitalization, and additional days of mechanical ventilation. The etiology of muscle dysfunction in the critically ill patient is multifactoral. Inactivity and inflammation, common phenomena to patients in the intensive care unit, are associated with myopathy and muscle dysfunction. Cytokines are small biological active molecules that regulate inflammation and have a direct effect on muscle wasting. The purpose of this article is to describe selected cytokines (ie, interleukin-1, interleukin-6, interleukin-10, and tumor necrosis factor), explain their role in muscle dysfunction, and explore the role of therapeutic activity as a moderator of muscle dysfunction and cytokine-mediated muscle damage.