Progressive Exercise for Anabolism in Kidney Disease (PEAK): A Randomized, Controlled Trial of Resistance Training during Hemodialysis

Decline in the Functional Status and Mortality in Patients on Hemodialysis: Results from the Japan Dialysis Outcome and Practice Patterns Study

OBJECTIVES

Patients with end-stage renal disease (ESRD) treated with hemodialysis suffer a high burden of poor functional status. Poor functional status is known as a strong, consistent predictor of mortality. However, little is known about the trajectory of functional status and its association with clinical outcomes in the ESRD population. We examined the association between a change in the functional status over time and all-cause mortality among patients on hemodialysis.

DESIGN AND METHODS

This was a prospective cohort study of 817 patients with ESRD on hemodialysis with repeat measures of functional status, who enrolled in the Japan Dialysis Outcomes and Practice Patterns Study phase V. The functional status was assessed based on the Katz Index and Lawton-Brody instrumental activities of daily living scale, and the assessments were conducted twice over a median of 361 (range: 339-378) days between 2012 and 2013. We classified patients into 2 groups based on having or not having at least a 1-point decline in the functional status score. To evaluate the association between the decline in the functional status and all-cause mortality with adjustment for potential confounders, a Cox regression analysis was conducted.

RESULTS

Over the study period, 19.9% of the patients showed a decline in the functional status score. During the follow-up period, 44 (5.4%) patients died. Using the Cox regression analysis and adjusting for potential confounders, it was determined that the decline in functional status score was significantly associated with higher mortality (incidence rate: 2.2 vs. 7.0 per 100 person-years; adjusted hazard ratio: 2.68; 95% confidence interval: 1.31-5.50).

CONCLUSIONS

The present study provides evidence that ESRD patients on hemodialysis demonstrating a decline in the functional status are at elevated risk of mortality. Our findings strengthen the evidence underpinning the importance of interventions to maintain the functional status in this vulnerable population.

Intradialytic resistance training: an effective and easy-to-execute strategy

Chronic kidney disease (CKD) alters the morphology and function of skeletal muscles, thereby decreasing patient physical capacity (PC) and quality of life (QoL). Intradialytic resistance training (IRT) is a pragmatic tool used to attenuate these complications. However, IRT has not been strongly adopted in nephrology care centers. This study aimed to assess the efficacy and safety of a low-cost, easy-to-use IRT protocol.

METHODS

The study enrolled 43 patients (52.8 ± 13.85 years) on HD for five to 300 months followed from April 2014 to July 2017. The efficacy of IRT was assessed based on PC - derived from muscle strength (MS) and preferred walking speed (PWS) - and QoL. The occurrence of adverse events was used as a measure of safety. The IRT protocol consisted of exercises of moderate to high intensity for the main muscle groups performed three times a week.

RESULTS

The mean follow-up time was 9.3 ± 3.24 months, for a total of 4,374 sessions of IRT. Compliance to the protocol was 96.5 ± 2.90%, and patients presented significant improvements in MS (from 27.3 ± 11.58 Kgf to 34.8 ± 10.77 Kgf) and PWS (from 0.99 ± 0.29 m/s to 1.26 ± 0.22 m/s). Physical and emotional components of QoL also increased significantly.

CONCLUSION

IRT led to significant increases in PC and higher scores in all domains of QoL. Important adverse events were not observed during intradialytic resistance training.

Whole body vibration to attenuate reduction of explosive force in chronic kidney disease patients: a randomized controlled trial

To investigate whether whole body vibration (WBV) training increases the explosive force of the knee extensors in chronic kidney disease (CKD) patients. Fourteen CKD patients undergoing hemodialysis were randomly allocated in WBV training or Sham group. Explosive force parameters (contractile impulse [CImp] and relative rate of force development [RFDr]) obtained in early (30 and 50 msec) and late phases (100 and 200 msec) of the knee extensors force/time curve. CImp and RFDr obtained at the early phase of force/time curve reduced after the intervention period, with a smaller decline for WBV (CImp at 50 msec [~-15% and -51%, P=0.038], RFDr at 30 msec [~-22% and -52%, P=0.044] and RFDr at 50 msec [~-11% and -54%; P=0.008]). In the late phase there was a lower decline for WBV group compared to Sham group, respectively: CImp: 100 msec (~-8% and -55%, P=0.025), 200 msec (~-3% and -46%, P= 0.025); RFDr 100 msec (~0.01% and -56%, P=0.033), 200 msec (~-5% and -36%, P=0.004). Three months of WBV training may attenuate the explosive force reduction in CKD patients.

Physical activity promotion for patients transitioning to dialysis using the "Exercise is Medicine" framework: a multi-center randomized pragmatic trial (EIM-CKD trial) protocol

BACKGROUND

Patients on dialysis are physically inactive, with most reporting activity levels below the fifth percentile of healthy age-matched groups. Several small studies have reported efficacy of diverse exercise interventions among persons with CKD and those on dialysis. However, no single intervention has been widely adopted in real-world practice, despite a clear need in this vulnerable population with high rates of mortality, frailty, and skilled nursing hospitalizations.

METHODS/DESIGN

We describe a pragmatic clinical trial for an exercise intervention among patients transitioning to dialysis. We will use an existing framework - Exercise is Medicine (EIM) - developed by the American College of Sports Medicine. After undertaking formative qualitative research to tailor the EIM framework to the advanced CKD population (eGFR < 30 ml/min/1.73m2), we will randomize 96 patients from two regions-Atlanta and Bay Area-in two intervention arms with incremental levels of clinical-community integration: physical activity assessment during Nephrology clinical visit, brief counseling at pre-dialysis education, and physical activity wearable (group 1) versus group 1 intervention components plus a referral to a free, EIM practitioner-led group exercise program over 16 weeks (group 2; 8 week core intervention; 8-week follow up). We will assess efficacy by comparing between group differences in minutes/week of objectively measured moderate intensity physical activity. To evaluate implementation, we will use questionnaires for assessing barriers to referral, participation and retention along the path of the intervention. Further we will have a plan for dissemination of the intervention by partnering with relevant stakeholders.

DISCUSSION

The overall goal is to inform the development of a practical, cost-conscious intervention "package" that addresses barriers and challenges to physical activity commonly faced by patients with advanced CKD and can be disseminated amongst interested practices.

TRIAL REGISTRATION

ClinicalTrials.gov identifier (Dated:10/17/2017): NCT03311763 .

Chronic kidney disease: considerations for monitoring skeletal muscle health and prescribing resistance exercise

Skeletal muscle wasting has gained interest as a primary consequence of chronic kidney disease (CKD) due to the relationship between skeletal muscle mass, mortality and major adverse cardiovascular events in this population. The combination of reductions in physical function, skeletal muscle performance and skeletal muscle mass places individuals with CKD at greater risk of sarcopenia. Therefore the monitoring of skeletal muscle composition and function may provide clinical insight into disease progression. Dual-energy X-ray absorptiometry and bioelectrical impedance analysis are frequently used to estimate body composition in people with CKD within clinical research environments, however, their translation into clinical practice has been limited. Proxy measures of skeletal muscle quality can be obtained using diagnostic ultrasound, providing a cost-effective and accessible imaging modality to aid further clinical research regarding changes in muscle composition. Clinicians and practitioners should evaluate the strengths and limitations of the available technology to determine which devices are most appropriate given their respective circumstances. Progressive resistance exercise has been shown to improve skeletal muscle hypertrophy of the lower extremities, muscular strength and health-related quality of life in end-stage renal disease, with limited evidence available in CKD predialysis. Fundamental principles (i.e. specificity, overload, variation, reversibility, individuality) can be used in the development of more advanced programs focused on improving specific neuromuscular and functional outcomes. Future research is needed to determine the applicability of skeletal muscle monitoring in clinical settings and the feasibility and efficacy of more advanced resistance exercise approaches in those with CKD predialysis.

A pilot study to relationship between urinary protein excretion and muscle strengthening in patients with acute onset renal disease

PURPOSE

The purpose of this study was to investigate urine protein excretion and the effect of muscle strengthening in patients with renal disease.

SUBJECTS

Twenty-eight patients (18 to 87 years old) with acute onset renal disease were treated with steroids at the Hospital of Shiga University of Medical Science. Maximum quadriceps force was measured, and 20-minutes sessions in resistance training were started. After 5 weeks, maximum quadriceps force was measured again.

RESULTS

Quadriceps force showed no significant difference between before and after intervention. There was negative correlation between mean urinary protein excretion and amount of change in quadriceps force over the 5 weeks (r=-0.40, p=0.038).

CONCLUSIONS

We observed the patients with reduced urine protein excretion are tends to easier to obtain muscle strengthening. On the other hand, there is a possibility that the patients with increased urine protein excretion are hard to obtain muscle strengthening, during the intervention.

Frailty and chronic kidney disease: current evidence and continuing uncertainties

Frailty, the state of increased vulnerability to physical stressors as a result of progressive and sustained degeneration in multiple physiological systems, is common in those with chronic kidney disease (CKD). In fact, the prevalence of frailty in the older adult population is reported to be 11%, whereas the prevalence of frailty has been reported to be greater than 60% in dialysis-dependent CKD patients. Frailty is independently linked with adverse clinical outcomes in all stages of CKD and has been repeatedly shown to be associated with an increased risk of mortality and hospitalization. In recent years there have been efforts to create an operationalized definition of frailty to aid its diagnosis and to categorize its severity. Two principal concepts are described, namely the Fried Phenotype Model of Physical Frailty and the Cumulative Deficit Model of Frailty. There is no agreement on which frailty assessment approach is superior, therefore, for the time being, emphasis should be placed on any efforts to identify frailty. Recognizing frailty should prompt a holistic assessment of the patient to address risk factors that may exacerbate its progression and to ensure that the patient has appropriate psychological and social support. Adequate nutritional intake is essential and individualized exercise programmes should be offered. The acknowledgement of frailty should prompt discussions that explore the future care wishes of these vulnerable patients. With further study, nephrologists may be able to use frailty assessments to inform discussions with patients about the initiation of renal replacement therapy.

Effect of continuous progressive resistance training during hemodialysis on body composition, physical function and quality of life in end-stage renal disease patients: a randomized controlled trial

Objective:

This study aimed to investigate the effect of continuous progressive resistance training on body composition, functional capacity and self-reported quality of life in end-stage renal disease patients.

Design:

A randomized controlled trial.

Subjects:

The study included 52 hemodialysis patients (aged 55.7 ± 14.03 years) randomized into exercise (progressive resistance training (PRT), n = 28) or control (CON, n = 24) groups.

Intervention:

Patients randomized into the PRT group received prescribed strength exercises in two sets of 15–20 repetitions, in a repetition maximum training zone regime, thrice a week for 12 weeks, during hemodialysis. Patients randomized into the CON group received a sham-exercise with active mobilization of the arms and legs without load and progression.

Main outcome measure:

Body composition using dual-energy X-ray absorptiometry (DXA), strength using handgrip dynamometry (HGS), repeated sit-to-stand test (STT), 6-minute walk test, flexibility and the SF-36 questionnaire (quality of life (QoL)) were assessed at baseline and at 12 weeks.

Results:

Leg lean mass ( P = 0.04, effect size (ES) of 0.56), bone mineral content ( P = 0.02, ES of 0.65), leg strength in STT repetitions ( P = 0.01, ES of 0.66) and flexibility ( P < 0.01, ES of 1.03) were significantly improved in the PRT group compared to the CON group. Walking capacity, HGS and QoL were not different between the groups.

Conclusion:

12 weeks of PRT with a repetition maximum training zone regime provided significant load to increase leg lean mass and STT performance as well as bone mineral content, compared to the CON, which continued to deteriorate. There was lack of efficacy on walking test, HGS and QoL.

Whole body vibration improves maximum voluntary isometric contraction of knee extensors in patients with chronic kidney disease: A randomized controlled trial

BACKGROUND

Whole body vibration (WBV) training improves maximum voluntary isometric contraction (MVIC) of knee extensors, postural balance, functional capacity, and quality of life (QOL) in several diseases. The objective was to assess the efficacy of WBV training in patients with chronic kidney disease (CKD) on hemodialysis (HD) in the interdialytic period.

METHOD

A randomized, controlled trial study with concealed allocation, intention-to-treat analysis, and triple blinding. Sixteen patients with CKD of both genders aged over 40 years were allocated in two groups, the WBV group or the sham group, training 2 times a week for 12 weeks. The primary outcome was knee extensor muscle strength, and the secondary outcomes were quadriceps thickness, distance walked, balance, and QOL.

RESULTS

The WBV group improved MVIC of knee extensors with a difference between groups in improvement of 117.29 N (95% CI, 32.25-202.24) at the end of training. The other outcomes were not different between groups. Practical applications: The WBV program has shown to be effective and may be able to help in prescribing the appropriate training program for CKD.

CONCLUSION

WBV training improves MVIC of knee extensors in patients with CKD on HD in the interdialytic period. WBV training could be considered in the management of patients with CKD.

Intradialytic exercise training modalities on physical functioning and health-related quality of life in patients undergoing maintenance hemodialysis: systematic review and meta-analysis

OBJECTIVE

To determine the effects of different intradialytic exercise training modalities on physical functioning and health-related quality of life of maintenance hemodialysis patients.

METHODS

We searched MEDLINE, Cochrane Trials Register and CINAHL for controlled trials that evaluated the effects of intradialytic exercise training for maintenance hemodialysis patients and published from the earliest available date to December 2017. Weighted mean difference and 95% confidence interval (CI) were calculated, and heterogeneity was assessed using the I² test.

RESULTS

Fifty-six studies met the study criteria, comprising a total of 2586 patients. Compared with no exercise, combined aerobic and resistance exercise resulted in significant improvement in peak VO₂ weighted mean difference (5.1 mL kg^-1 min^-1; 95% CI: 3.4, 6.8 mL kg^-1 min^-1), depression symptoms (-7.32; 95% CI -9.31, -5.33) and both physical function (10.67 points; 95% CI 1.08, 20.25 points) and vitality (10.01 points; 95% CI 4.30, 15.72 points) domains of health-related quality of life. Resistance exercise alone was significantly associated with improvement in the 6-minute walk test distance (30.2 m; 95% CI 24.6, 35.9 m), knee extensor strength (0.6 N; 95% CI 0.1, 1.0 N) and Physical Component Score of health-related quality of life (9.53 points; 95% CI -3.09, 22.15 points) when compared with control group. Aerobic exercise alone was not significantly associated with aerobic capacity and quality of life improvement.

CONCLUSION

The results provide support to interventions that combine intradialytic aerobic and resistance exercises to improve physical functioning and quality of life in end-stage renal disease patients undergoing hemodialysis.

Effect of intradialytic resistance training on pulse wave velocity and associated cardiovascular disease biomarkers in end stage renal disease

AIMS

Cardiovascular disease (CVD) is the leading cause of mortality in patients with end-stage renal disease (ESRD) receiving maintenance haemodialysis treatment. This study investigated the effect of a 12-week intradialytic progressive resistance training (PRT) intervention on pulse wave velocity (PWV) and associated haemodynamic, anthropometric, and hematologic outcomes in patients with ESRD.

METHODS

Twenty-two patients with ESRD (59% men, 71.3 ± 11.0 years) were recruited. Supervised PRT (three sets of 11 exercises) was prescribed three times per week during routine dialysis. The primary outcome was brachial-ankle PWV via applanation tonometry. Secondary outcomes included augmentation index, brachial and aortic blood pressures, endothelial progenitor cells, C-reactive protein, blood lipids and anthropometrics.

RESULTS

The intradialytic PRT regimen resulted in no significant change in PWV between control and intervention periods [mean difference = 0 (95% CI = -0.1 to 0.1); P = 0.58]. Similarly, no significant change was noted in any secondary outcome measures between the control and intervention periods. Post-hoc analyses limited to high adherers (≥75% attendance; n = 11) did not differ from the primary analysis, indicating no dose-response effect of our intervention.

CONCLUSION

Our 12-week PRT intervention did not change PWV or any secondary outcomes. Future studies should determine if higher dosages of intradialytic PRT (i.e. longer duration and/or higher intensity) can be applied as a method to improve arterial stiffness to potentially reduce cardiovascular disease and associated mortality this cohort.

The Impact of Hemodialysis on Spatio-Temporal Characteristics of Gait and Role of Exercise: A Systematic Review

Background: People with end-stage kidney disease (ESKD) on hemodialysis (HD) commonly have functional impairments. The purpose of this systematic review was to evaluate the effect of HD on spatio-temporal characteristics of gait, and effect of exercise on these parameters. Methods: Electronic databases were searched to identify relevant citations. Extracted data was computed using a random effects model for means (Hedges’ and 95% confidence interval (CI). Results: 27 studies met inclusion criteria. Mean values: gait speed (GS)—1.0 m/s (CI: 0.9–1.1 m/s; 16 studies), fast walking speed (FWS)—1.5 m/s (CI: 1.3–1.6 m/s; 7 studies), timed get-up & go test (TUG) —6.8 s (CI: 6.1–7.5 s; 2 studies), walk tests (WT) 193.0 s (CI: 116.0–270.0; 5 studies), 6 min-walk-test (6MWT)—386.6 m (CI: 243.2–530.0 m; 11 studies). 4 studies compared participants on HD with normal controls and 10 studies evaluated the effect of nutrition/exercise. Conclusions: Compared to age-matched populations, people with ESKD/HD had significantly slower GS and reduced walk distances; with intervention, the change in the distance walked was significant. Further research is required to evaluate the effect of HD on gait parameters, and the type of exercise/nutrition that will lead to meaningful changes.

Physical Function and Physical Activity in Peritoneal Dialysis Patients

BACKGROUND

Physical functioning (PF) and physical activity (PA) are low in patients treated with maintenance hemodialysis (MHD). Little information exists on this topic in patients treated with peritoneal dialysis (PD). The objective of this study was to compare PF and PA in patients with Stage-5 chronic kidney disease (CKD) treated with PD and in-center MHD.

METHODS

Physical functioning was measured in 45 prevalent PD patients using standard physical performance measures that include gait speed, chair stand, standing balance, 6-minute-walk, incremental shuttle walk and self-reported PF using the short form (SF)-36 questionnaire. Physical activity was determined from self-report and using the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire. Scores for the short physical performance battery (SPPB) were calculated. In-center MHD patients were matched by age, gender, and diabetes status to the PD patients.

RESULTS

Unadjusted comparisons showed significantly higher 6-minute-walk distance, shuttle-walk distance and hand-grip in the PD patients. Adjustment in multiple regression analysis resulted in only gait speed being significantly different between the groups. All test results in both groups were lower than reference values for age and gender in the general population, and were at the levels indicating impairment. Physical activity was not different between the 2 groups (average age 49 yrs), and both groups had weekly caloric expenditure from all exercise and from moderate-intensity exercise that was similar to older (> 70 yrs) community-dwelling adults. Adjusted association indicated that PA was significantly associated with shuttle-walk distance.

CONCLUSIONS

Physical functioning and PA measures were low in both PD and MHD groups. Interventions to improve PA and PF should be strongly considered for both PD and MHD patients.

Quality of life measures predict cardiovascular health and physical performance in chronic renal failure patients

BACKGROUND

Patients with advanced chronic kidney disease (CKD) experience complex functional and structural changes of the cardiopulmonary and musculoskeletal system. This results in reduced exercise tolerance, quality of life and ultimately premature death. We investigated the relationship between subjective measures of health related quality of life and objective, standardised functional measures for cardiovascular and pulmonary health.

METHODS

Between April 2010 and January 2013, 143 CKD stage-5 or CKD5d patients (age 46.0±1.1y, 62.2% male), were recruited prospectively. A control group of 83 healthy individuals treated for essential hypertension (HTN; age 53.2±0.9y, 48.22% male) were recruited at random. All patients completed the SF-36 health survey questionnaire, echocardiography, vascular tonometry and cardiopulmonary exercise testing.

RESULTS

Patients with CKD had significantly lower SF-36 scores than the HTN group; for physical component score (PCS; 45.0 vs 53.9, p<0.001) and mental component score (MCS; 46.9 vs. 54.9, p<0.001). CKD subjects had significantly poorer exercise tolerance and cardiorespiratory performance compared with HTN (maximal oxygen uptake; VO2peak 19.9 vs 25.0ml/kg/min, p<0.001). VO2peak was a significant independent predictor of PCS in both groups (CKD: b = 0.35, p = 0.02 vs HTN: b = 0.27, p = 0.001). No associations were noted between PCS scores and echocardiographic characteristics, vascular elasticity and cardiac biomarkers in either group. No associations were noted between MCS and any variable. The interaction effect of study group with VO2peak on PCS was not significant (ΔB = 0.08; 95%CI -0.28-0.45, p = 0.7). However, overall for a given VO2peak, the measured PCS was much lower for patients with CKD than for HTN cohort, a likely consequence of systemic uremia effects.

CONCLUSION

In CKD and HTN, objective physical performance has a significant effect on quality of life; particularly self-reported physical health and functioning. Therefore, these quality of life measures are indeed a good reflection of physical health correlating highly with objective physical performance measures.

Efficacy of blood flow restriction exercise during dialysis for end stage kidney disease patients: protocol of a randomised controlled trial

BACKGROUND

Exercise during haemodialysis improves strength and physical function. However, both patients and clinicians are time poor, and current exercise recommendations add an excessive time burden making exercise a rare addition to standard care. Hypothetically, blood flow restriction exercise performed during haemodialysis can provide greater value for time spent exercising, reducing this time burden while producing similar or greater outcomes. This study will explore the efficacy of blood flow restriction exercise for enhancing strength and physical function among haemodialysis patients.

METHODS

This is a randomised controlled trial design. A total of 75 participants will be recruited from haemodialysis clinics. Participants will be allocated to a blood flow restriction cycling group, traditional cycling group or usual care control group. Both exercising groups will complete 3 months of cycling exercise, performed intradialytically, three times per week. The blood flow restriction cycling group will complete two 10-min cycling bouts separated by a 20-min rest at a subjective effort of 15 on a 6 to 20 rating scale. This will be done with pressurised cuffs fitted proximally on the active limbs during exercise at 50% of a pre-determined limb occlusion pressure. The traditional cycling group will perform a continuous 20-min bout of exercise at a subjective effort of 12 on the same subjective effort scale. These workloads and volumes are equivalent and allow for comparison of a common blood flow restriction aerobic exercise prescription and a traditional aerobic exercise prescription. The primary outcome measures are lower limb strength, assessed by a three repetition maximum leg extension test, as well as objective measures of physical function: six-minute walk test, 30-s sit to stand, and timed up and go. Secondary outcome measures include thigh muscle cross sectional area, body composition, routine pathology, quality of life, and physical activity engagement.

DISCUSSION

This study will determine the efficacy of blood flow restriction exercise among dialysis patients for improving key physiological outcomes that impact independence and quality of life, with reduced burden on patients. This may have broader implications for other clinical populations with similarly declining muscle health and physical function, and those contraindicated to higher intensities of exercise.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Register: ACTRN12616000121460.

Does resistance exercise performed during dialysis modulate Nrf2 and NF-κB in patients with chronic kidney disease?

Studies have shown that nuclear factor erythroid 2-related factor 2 (Nrf2) can be modulated by physical exercise. However, the impact of resistance exercise has never been investigated in patients with chronic kidney disease (CKD). The aim of this study was to evaluate the effects of resistance exercise programs on the expression of transcription factors Nrf2 and nuclear factor κB (NF-κB) in CKD patients on hemodialysis (HD). Patients on an HD program were randomly assigned to an exercise group of 25 patients (54.5% women, aged 45.7±15.2years and time on dialysis=71.2±45.5months) or a control group of 19 patients who had no exercise intervention (61.5% women, aged 42.5±13.5years and time on dialysis=70.1±49.9months). A strength exercise program was performed 3 times a week during the HD sessions. Peripheral blood mononuclear cells were isolated and processed for the expression of Nrf2 and NF-κB by quantitative real-time polymerase chain reaction 3months before and after the exercise program. Using an enzyme-linked immunosorbent assay, the activity of glutathione peroxidase (GPx) as well as the products of high-sensitivity C-reactive protein and nitric oxide (NO) were assessed. Nrf2 expression (ranging from 0.86±0.4 to 1.76±0.8) and GPx activity were significantly increased after exercise intervention. In the exercise group, no difference in the levels of NO was observed; however, there was a significant reduction in the control group. In conclusion, these data suggest that resistance exercises seem to be capable of inducing Nrf2 activation in CKD patients on HD.

Effect of endurance training and branched-chain amino acids on the signaling for muscle protein synthesis in CKD model rats fed a low-protein diet

A low-protein diet (LPD) protects against the progression of renal injury in patients with chronic kidney disease (CKD). However, LPD may accelerate muscle wasting in these patients. Both exercise and branched-chain amino acids (BCAA) are known to increase muscle protein synthesis by activating the mammalian target of rapamycin (mTOR) pathway. The aim of this study was to investigate whether endurance exercise and BCAA play a role for increasing muscle protein synthesis in LPD-fed CKD (5/6 nephrectomized) rats. Both CKD and sham rats were pair-fed on LPD or LPD fortified with a BCAA diet (BD), and approximately one-half of the animals in each group was subjected to treadmill exercise (15 m/min, 1 h/day, 5 days/wk). After 7 wk, renal function was measured, and soleus muscles were collected to evaluate muscle protein synthesis. Renal function did not differ between LPD- and BD-fed CKD rats, and the treadmill exercise did not accelerate renal damage in either group. The treadmill exercise slightly increased the phosphorylation of p70s6 kinase, a marker of mTOR activity, in the soleus muscle of LPD-fed CKD rats compared with the sham group. Furthermore, BCAA supplementation of the LPD-fed, exercise-trained CKD rats restored the phosphorylation of p70s6 kinase to the same level observed in the sham group; however, the corresponding induced increase in muscle protein synthesis and muscle mass was marginal. These results indicate that the combination of treadmill exercise and BCAA stimulates cell signaling to promote muscle protein synthesis; however, the implications of this effect for muscle growth remain to be clarified.

Exercise Training in Elderly People Undergoing Hemodialysis: A Systematic Review and Meta-analysis

Introduction

Previous reviews have indicated the effectiveness of exercise in people undergoing hemodialysis. However, these analyses did not take into account whether the subjects were elderly. We performed a systematic review of the effects of exercise training in elderly people undergoing hemodialysis and updated the evidence of exercise for people undergoing hemodialysis by adding recent research data.

Methods

We searched 8 electronic databases up to June 2016. Inclusion criteria were as follows: randomized controlled trial, English publication, subjects aged 18 and older undergoing hemodialysis, evaluation of physical function as an outcome of exercise intervention. We defined elderly as age 60 years and older. The main outcomes were exercise tolerance (peak/maximum oxygen consumption) and walking ability (6-minute walk distance). Secondary outcomes were lower extremity muscle strength and quality of life.

Results

After screening of 10,923 references, 30 comparisons were entered into the analysis. However, because we found only 1 study in which elderly subjects were treated, we could not perform a meta-analysis for these people. For the general population undergoing hemodialysis, supervised exercise training was shown to significantly increase peak/maximum oxygen consumption (standard mean difference, 0.62; 95% confidence interval 0.38-0.87; P < 0.001), 6-minute walk distance (standard mean difference, 0.58; 95% confidence interval 0.24-0.93; P < 0.001), lower extremity muscle strength (standard mean difference, 0.94; 95% confidence interval 0.67-1.21; P < 0.001), and quality of life (standard mean difference, 0.53; 95% confidence interval 0.52-0.82; P < 0.001).

Discussion

Our analysis on the effectiveness of exercise training in elderly people undergoing hemodialysis as compared with nonelderly people was somewhat inconclusive. Future studies should be carried out for elderly people to identify the most favorable exercise program for this population.

Regular exercise during haemodialysis promotes an anti-inflammatory leucocyte profile

Background

Cardiovascular disease is the most common cause of mortality in haemodialysis (HD) patients and is highly predicted by markers of chronic inflammation. Regular exercise may have beneficial anti-inflammatory effects, but this is unclear in HD patients. This study assessed the effect of regular intradialytic exercise on soluble inflammatory factors and inflammatory leucocyte phenotypes.

Methods

Twenty-two HD patients from a centre where intradialytic cycling was offered thrice weekly and 16 HD patients receiving usual care volunteered. Exercising patients aimed to cycle for 30 min at rating of perceived exertion of ‘somewhat hard’. Baseline characteristics were compared with 16 healthy age-matched individuals. Physical function, soluble inflammatory markers and leucocyte phenotypes were assessed again after 6 months of regular exercise.

Results

Patients were less active than their healthy counterparts and had significant elevations in measures of inflammation [interleukin-6 (IL-6), C-reactive protein (CRP), tumour necrosis factor-α (TNF-α), intermediate and non-classical monocytes; all P < 0.001]. Six months of regular intradialytic exercise improved physical function (sit-to-stand 60). After 6 months, the proportion of intermediate monocytes in the exercising patients reduced compared with non-exercisers (7.58 ± 1.68% to 6.38 ± 1.81% versus 6.86 ± 1.45% to 7.88 ± 1.66%; P < 0.01). Numbers (but not proportion) of regulatory T cells decreased in the non-exercising patients only (P < 0.05). Training had no significant effect on circulating IL-6, CRP or TNF-α concentrations.

Conclusions

These findings suggest that regular intradialytic exercise is associated with an anti-inflammatory effect at a circulating cellular level but not in circulating cytokines. This may be protective against the increased risk of cardiovascular disease and mortality that is associated with chronic inflammation and elevated numbers of intermediate monocytes.

Prehabilitation for the Frail Patient Approaching ESRD

Frailty is a distinct phenotype that is highly prevalent in chronic kidney disease (CKD) and appears to be more prevalent with decreasing glomerular filtration rate. Exercise training or intervention to increase physical activity may ameliorate poor physical functioning and frailty, and even may improve survival in patients with CKD. Although exercise interventions improve outcomes across the spectrum of CKD, including patients treated with dialysis, patients treated with dialysis face barriers to exercise that patients with predialysis CKD do not. Rehabilitation at earlier stages of CKD (or prehabilitation before dialysis) might be more beneficial than not addressing the decreasing physical functioning and low physical activity until patients are receiving dialysis. This review summarizes available literature on frailty in the CKD and end-stage renal disease population, including exercise interventions and the limited evidence for prehabilitation as a strategy.

Intradialytic Exercise is Medicine for Hemodialysis Patients

When a person's kidneys fail, hemodialysis (HD) is the most common treatment modality. With a growing number of patients requiring this life-sustaining treatment, and with evidence illustrating the significant physical dysfunction of this population, encouraging exercise is essential. The use of intradialytic exercise, as a novel and efficient use of time during HD, is well established in Australia and some European nations; however, it is slower to start in North America. While a large number of small studies have demonstrated numerous benefits and safe delivery of intradialytic exercise training for patients with end-stage kidney disease, intradialytic exercise is rarely delivered as standard of care. It is of utmost importance for health care staff to overcome barriers and bring theory into practice. Included in this report are current recommendations from governing bodies, expert opinion, as well as established policies and procedures from a successful intradialytic exercise program in Canada.

Correlates of Physical Functioning and Performance Across the Spectrum of Kidney Function

The aim of this study was to determine the extent to which poor physical functioning, low participation in physical activity, and muscle atrophy observed among patients on hemodialysis are evident in the earlier stages of chronic kidney disease (CKD). We enrolled adults in three groups: no CKD, Stages 3 to 4 CKD, and hemodialysis. Outcomes measured were physical activity, muscle size, thigh muscle strength, physical performance, and self-reported physical function. Patients with CKD had muscle area intermediate between the no CKD and hemodialysis groups, but they had low levels of physical activity that were similar to the hemodialysis group. Physical activity and muscle size were significantly associated with all outcomes. Kidney function was not significantly associated with muscle strength or physical performance after adjustment for physical activity and muscle size. In conclusion, interventions aimed to increase muscle mass and energy expenditure might have an impact on improving physical function of CKD patients.

Sex Differences in Muscle Wasting

With aging and other muscle wasting diseases, men and women undergo similar pathological changes in skeletal muscle: increased inflammation, enhanced oxidative stress, mitochondrial dysfunction, satellite cell senescence, elevated apoptosis and proteasome activity, and suppressed protein synthesis and myocyte regeneration. Decreased food intake and physical activity also indirectly contribute to muscle wasting. Sex hormones also play important roles in maintaining skeletal muscle homeostasis. Testosterone is a potent anabolic factor promoting muscle protein synthesis and muscular regeneration. Estrogens have a protective effect on skeletal muscle by attenuating inflammation; however, the mechanisms of estrogen action in skeletal muscle are less well characterized than those of testosterone. Age- and/or disease-induced alterations in sex hormones are major contributors to muscle wasting. Hence, men and women may respond differently to catabolic conditions because of their hormonal profiles. Here we review the similarities and differences between men and women with common wasting conditions including sarcopenia and cachexia due to cancer, end-stage renal disease/chronic kidney disease, liver disease, chronic heart failure, and chronic obstructive pulmonary disease based on the literature in clinical studies. In addition, the responses in men and women to the commonly used therapeutic agents and their efficacy to improve muscle mass and function are also reviewed.

Exercise Training Alters the Bone Mineral Density of Hemodialysis Patients

Marinho, SM, Moraes, C, Barbosa, JEdSM, Eduardo, JCC, Fouqe, D, Pelletier, S, and Mafra, D. Exercise training alters the bone mineral density of hemodialysis patients. J Strength Cond Res 30(10): 2918-2923, 2016-Patients with chronic kidney disease undergoing hemodialysis (HD) frequently present low bone mineral density (BMD), and exercise may be useful for treating bone loss. This study aimed to assess the effects of an intradialytic resistance exercise training program (RETP) on BMD in HD patients. Twenty-one patients were enrolled into 2 groups; 10 patients performed exercise (80.0% men; 46.9 ± 12.1 years; 27.0 ± 3.4 kg·m) and 11 patients were in the control group (54.5% men; 50.5 ± 11.5 years; 24.1 ± 8.7 kg·m). Dual-energy x-ray absorptiometry was used to measure the BMD, lean mass, and body fat before and after the supervised RETP (performed with elastic bands and ankle cuffs in both lower limbs 3 times a week for 24 weeks-72 sessions). In the exercise group, 30.0% of patients presented with osteopenia and 20.0% osteoporosis and in the control group, 45.5% osteopenia and 36.4% osteoporosis. Only in the exercise group, the osteoporosis percentage was reduced to 10.0% and the femoral neck BMD and T-score improved from 0.89 ± 0.1 to 0.93 ± 0.1 g·cm and from -1.3 ± 0.8 to -1.0 ± 0.8 g·cm (p ≤ 0.05), respectively, after the intervention. In contrast, these parameters were reduced in the control group. The results suggest that resistance exercise may be useful for improving the BMD in HD patients. In summary, 24 weeks of the supervised RETP played a role in improving the BMD of HD patients.

The effects of resistance exercise and oral nutritional supplementation during hemodialysis on indicators of nutritional status and quality of life

BACKGROUND

Protein-energy wasting (PEW) is common in patients undergoing hemodialysis (HD). Studies have assessed the positive effect of oral nutritional supplementation (ONS) or resistance exercise (RE) on nutritional status (NS) markers in patients undergoing HD.

METHODS

The aim of this study was to assess the effect of ONS and RE on NS and the quality of life (QOL) of 36 patients undergoing HD. In a randomized clinical trial, patients were divided into the following two groups: a control group (ONS) that received a can of ONS during their HD sessions and an intervention group (ONS + RE) that received a can of ONS and underwent a 40-min session of RE during their HD sessions. Both interventions lasted 12 weeks. The patients' anthropometric, biochemical, dietetic and bioelectrical impedance measurements as well as their QOL, evaluated using the Kidney Disease Quality of Life Short Form, were recorded.

RESULTS

At baseline, 55.5% of patients presented with PEW according to International Society of Renal Nutrition and Metabolism criteria (20 patients). We found statistically significant changes from baseline in both groups, such as increases in body weight, body mass index, midarm circumference, midarm muscle circumference, triceps skinfold thickness, fat mass percentage, handgrip strength, phase angle and serum albumin. A decrease in the prevalence of PEW was observed in both groups at the end of the intervention. A delta comparison between groups showed no statistically significant differences in the anthropometric and biochemical parameters. No significant improvement was observed in QOL and body composition measured by bioimpedance vector analysis. Dietary energy and protein intake increased significantly during the study period for all patients.

CONCLUSION

Oral nutritional supplementation during HD improves NS. The addition of RE during HD does not seem to augment the acute anabolic effects of intradialytic ONS on NS.

Effect of exercise training on C reactive protein: a systematic review and meta-analysis of randomised and non-randomised controlled trials

PURPOSE

C-reactive protein (CRP) is a marker of chronic systemic inflammation frequently used in cardiovascular disease risk assessment. The purpose of this meta-analysis was to provide a quantitative estimate of the magnitude of change in CRP following participation in physical exercise interventions.

METHODS

All studies included in the meta-analysis were peer reviewed and published in English. Human participants were assigned to a non-exercise comparison group or exercise training group, with the intervention lasting ≥2 weeks. CRP levels were measured at baseline, during and/or after completion of the exercise training programme. Random-effects models were used to aggregate a mean effect size (ES), 95% CIs and potential moderators.

RESULTS

83 randomised and non-randomised controlled trials met the inclusion criteria and resulted in 143 effects (n=3769). The mean ES of 0.26 (95% CI 0.18 to 0.34, p<0.001) indicated a decrease in CRP following exercise training. A decrease in body mass index (BMI; β=1.20, SE=0.25, p<0.0001) and %Fat (β=0.76, SE=0.21, p=0.0002) were associated with a decrease in CRP, independently accounting for 11.1% and 6.6% of the variation in response, respectively. Exercise training led to a greater reduction in CRP when accompanied by a decrease in BMI (ES=0.38, 95% CI 0.26 to 0.50); however, a significant improvement in CRP occurred in the absence of weight loss (ES=0.19, 95% CI 0.10 to 0.28; both p<0.001).

CONCLUSIONS

These results suggest that engaging in exercise training is associated with a decrease in CRP levels regardless of the age or sex of the individual; however, greater improvements in CRP level occur with a decrease in BMI or %Fat.

Design and methods of CYCLE-HD: improving cardiovascular health in patients with end stage renal disease using a structured programme of exercise: a randomised control trial

BACKGROUND

There is emerging evidence that exercise training could positively impact several of the cardiovascular risk factors associated with sudden cardiac death amongst patients on haemodialysis. The primary aim of this study is to evaluate the effect of an intradialytic exercise programme on left ventricular mass.

METHOD AND DESIGN

Prospective, randomised cluster open-label blinded endpoint clinical trial in 130 patients with end stage renal disease on haemodialysis. Patients will be randomised 1:1 to either 1) minimum of 30 min continuous cycling thrice weekly during dialysis or 2) standard care. The primary outcome is change in left ventricular mass at 6 months, assessed by cardiac MRI (CMR). In order to detect a difference in LV mass of 15 g between groups at 80 % power, a sample size of 65 patients per group is required. Secondary outcome measures include abnormalities of cardiac rhythm, left ventricular volumes and ejection fraction, physical function measures, anthropometric measures, quality of life and markers of inflammation, with interim assessment for some measures at 3 months.

DISCUSSION

This study will test the hypothesis that an intradialytic programme of exercise leads to a regression in left ventricular mass, an important non-traditional cardiovascular risk factor in end stage renal disease. For the first time this will be assessed using CMR. We will also evaluate the efficacy, feasibility and safety of an intradialytic exercise programme using a number of secondary end-points. We anticipate that a positive outcome will lead to both an increased patient uptake into established intradialytic programmes and the development of new programmes nationally and internationally.

TRIAL REGISTRATION NUMBER

ISRCTN11299707 (registration date 5(th) March 2015).

Intradialytic aerobic cycling exercise alleviates inflammation and improves endothelial progenitor cell count and bone density in hemodialysis patients

Inflammation, endothelial dysfunction, and mineral bone disease are critical factors contributing to morbidity and mortality in hemodialysis (HD) patients. Physical exercise alleviates inflammation and increases bone density. Here, we investigated the effects of intradialytic aerobic cycling exercise on HD patients. Forty end-stage renal disease patients undergoing HD were randomly assigned to either an exercise or control group. The patients in the exercise group performed a cycling program consisting of a 5-minute warm-up, 20 minutes of cycling at the desired workload, and a 5-minute cool down during 3 HD sessions per week for 3 months. Biochemical markers, inflammatory cytokines, nutritional status, the serum endothelial progenitor cell (EPC) count, bone mineral density, and functional capacity were analyzed. After 3 months of exercise, the patients in the exercise group showed significant improvements in serum albumin levels, the body mass index, inflammatory cytokine levels, and the number of cells positive for CD133, CD34, and kinase insert domain-conjugating receptor. Compared with the exercise group, the patients in the control group showed a loss of bone density at the femoral neck and no increases in EPCs. The patients in the exercise group also had a significantly greater 6-minute walk distance after completing the exercise program. Furthermore, the number of EPCs significantly correlated with the 6-minute walk distance both before and after the 3-month program. Intradialytic aerobic cycling exercise programs can effectively alleviate inflammation and improve nutrition, bone mineral density, and exercise tolerance in HD patients.

The feasibility of progressive resistance training in women with polycystic ovary syndrome: a pilot randomized controlled trial

BACKGROUND

To evaluate the feasibility of executing a randomized controlled trial of progressive resistance training (PRT) in women with polycystic ovary syndrome (PCOS).

METHODS

Women with PCOS were randomized to an experimental (PRT) group or a no-exercise (usual care) control group. The PRT group was prescribed two supervised and two unsupervised (home-based) training sessions per week for 12 weeks. Feasibility outcomes included recruitment and attrition, adherence, adverse events, and completion of assessments. Secondary outcomes, collected pre and post intervention, included a range of pertinent physiological, functional and psychological measures.

RESULTS

Fifteen participants were randomised into the PRT group (n = 8) or control group (n = 7); five women (n = 2 in PRT group and n = 3 in control group) withdrew from the study. The most successful recruitment sources were Facebook (40 %) and online advertisement (27 %), while least successful methods were referrals by clinicians, colleagues and flyers. In the PRT group, attendance to supervised sessions was higher (95 %; standard deviation ±6 %) compared to unsupervised sessions (51 %; standard deviation ±28 %). No adverse events were attributed to PRT. Change in menstrual cycle status was not significantly different between groups over time (p = 0.503). However, the PRT group significantly increased body weight (p = 0.01), BMI (p = 0.04), lean mass (p = 0.01), fat-free mass (p = 0.005) and lower body strength (p = 0.03), while reducing waist circumference (p = 0.03) and HbA1c (p = 0.033) versus the control group. The PRT group also significantly improved across several domains of disease-specific and general health-related quality of life, depression, anxiety and exercise self-efficacy.

CONCLUSION

A randomized controlled trial of PRT in PCOS would be feasible, and this mode of exercise may elicit a therapeutic effect on clinically important outcomes in this cohort. The success of a large-scale trial required to confirm these findings would be contingent on addressing the feasibility hurdles identified in this study with respect to recruitment, attrition, compliance, and collection of standardized clinical data.

TRIAL REGISTRATION

Australia New Zealand Clinical Trials Registry; ACTRN12614000517673 Registered 15 May 2014.

Sarcopenia and Physical Inactivity in Patients With Chronic Kidney Disease

Sarcopenia and physical inactivity synergistically progress in patients with chronic kidney disease (CKD) and are strong predictors of mortality in this population. Exercise training and essential amino acids and vitamin D supplements may contribute to improving sarcopenia and physical inactivity in CKD patients.

In Hemodialysis Patients, Intradialytic Resistance Exercise Improves Osteoblast Function: A Pilot Study

OBJECTIVE

Abnormalities in mineral and bone metabolism are frequent in chronic kidney disease patients. Physical exercise can improve many indicators of physical functioning, and recent studies showed beneficial effects on bone mineral density in the general population. The aim of this study was to evaluate the effects of resistance exercise training on bone markers and body composition in hemodialysis (HD) patients.

DESIGN

This was a randomized controlled trial.

SUBJECTS

The study included 13 HD patients (46.2% men).

INTERVENTION

Patients were divided into a control group and an exercise group, which performed 8 weeks of intradialytic resistance exercise. Serum sclerostin, bone alkaline phosphatase (BAP), insulin, leptin, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and body composition were measured before and after the exercise period.

RESULTS

In the exercise group, BAP levels increased from 11.4 ± 6.5 to 14.6 ± 6.4 U/L (P < .05) and serum 1,25-dihydroxyvitamin D levels from 46.0 ± 23.5 to 87.2 ± 31.8 ng/mL (P < .05). After exercise, serum BAP levels were inversely correlated with serum sclerostin (r = -0.96, P < .05). There was no change in body composition in either group.

CONCLUSION

Resistance exercise training appears to be an interesting approach for stimulating BAP production in HD patients and may prevent bone loss and stimulate bone formation.

Body composition in chronic kidney disease

PURPOSE OF REVIEW

To summarize the latest information on body composition among patients with chronic kidney disease and its association with outcomes.

RECENT FINDINGS

Obesity is increasing among patients with end-stage renal disease and is more prevalent when direct measures of adiposity are used rather than BMI. High BMI is not associated with better survival among patients with earlier chronic kidney disease or after kidney transplantation, suggesting that excess fat is most protective among the sickest patients. Despite the positive association between BMI and survival among patients with end-stage renal disease, visceral fat is associated with coronary artery calcification and adverse cardiovascular events. Muscle wasting is prominent among patients with chronic kidney disease, sometimes even in the setting of obesity. Obesity and muscle wasting are associated with worse physical functioning. Indicators of low muscle size and strength are associated with higher mortality. Some interventions can affect body composition, but whether they affect survival has not been determined.

SUMMARY

Recent studies show that a high BMI is not protective for all patients with chronic kidney disease and is associated with poor physical functioning and frailty. Visceral adiposity is associated with adverse cardiovascular outcomes. Sarcopenia is common among patients with end-stage renal disease and is associated with worse physical performance and higher mortality.

Lower C-reactive protein and better hemodialysis survival are associated with regular exercise activity: Longitudinal outcomes from the ACTIVE-ADIPOSE special study

Introduction Cross-sectional and longitudinal studies in the general population have shown that a physically active lifestyle may have anti-inflammatory properties, but evidence from studies conducted with maintenance hemodialysis (HD) patients is limited. Methods A multicenter prospective cohort of 755 HD participants aged 20-92 was evaluated in a USRDS special study 2009-2013. Kilocalories/week (kcal/week) of leisure time physical activity (LTPA) was estimated from the Minnesota Leisure Time Activity questionnaire. Predialysis serum samples were obtained concurrent with LTPA report date. Generalized estimating equations (GEE) examined association of participants' LTPA and log-normalized CRP across 24 months. Cox proportional hazards models investigated LTPA and survival over a median follow-up of 718 days. Findings Baseline median CRP concentration was lower for participants with 500+ kcal/week LTPA vs. those with <500 kcal/week LTPA (3.4 mg/L vs. 4.6 mg/L; P = 0.03). Participants who reported lower LTPA (<500 kcal/week) at both baseline and 12 months had a borderline significant increase in CRP concentration (within-group change 4.8 [1.9-10.4] to 5.8 [1.6-15.7]; P = 0.08). Lower LTPA was associated with higher log CRP over 24 months in adjusted GEE analyses (β coefficient = 0.16 [95% CI 0.02-0.31]; P = 0.03). 67/364 (18%) and 43/391 (11%) deaths occurred, respectively, among participants reporting <500 vs. 500+ kcal/week LTPA [adjusted mortality hazard ratio 1.63 (CI, 1.07, 2.47)]. Discussion The data suggest that increased estimated levels of LTPA, a physical activity/exercise opportunity widely applicable to HD patients, may be associated with lower CRP concentration as well as better survival outcome.

Effects of exercise in the whole spectrum of chronic kidney disease: a systematic review

Chronic kidney disease (CKD) is a public health problem. Although physical activity is essential for the prevention and treatment of most chronic diseases, exercise is rarely prescribed for CKD patients. The objective of the study was to search for and appraise evidence on the effectiveness of exercise interventions on health endpoints in CKD patients. A systematic review was performed of randomized clinical trials (RCTs) designed to compare exercise with usual care regarding effects on the health of CKD patients. MEDLINE, EMBASE, Cochrane Central, Clinical Trials registry, and proceedings of major nephrology conference databases were searched, using terms defined according to the PICO (Patient, Intervention, Comparison and Outcome) methodology. RCTs were independently evaluated by two reviewers. A total of 5489 studies were assessed for eligibility, of which 59 fulfilled inclusion criteria. Most of them included small samples, lasted from 8 to 24 weeks and applied aerobic exercises. Three studies included only kidney transplant patients, and nine included pre-dialysis patients. The remaining RCTs allocated hemodialysis patients. The outcome measures included quality of life, physical fitness, muscular strength, heart rate variability, inflammatory and nutritional markers and progression of CKD. Most of the trials had high risk of bias. The strongest evidence is for the effects of aerobic exercise on improving physical fitness, muscular strength and quality of life in dialysis patients. The benefits of exercise in dialysis patients are well established, supporting the prescription of physical activity in their regular treatment. RCTs including patients in earlier stages of CKD and after kidney transplantation are urgently required, as well as studies assessing long-term outcomes. The best exercise protocol for CKD patients also remains to be established.

Effects of acute resistance exercise on acyl-ghrelin and obestatin levels in hemodialysis patients: a pilot study

Chronic physical exercises may be beneficial to modulate appetite hormones as acyl-ghrelin (orexigenic) and obestatin (anorexigenic) in chronic kidney disease (CKD) patients; however, there are no data about the effects of acute exercises on these hormones. Thus, the aim of the present study was to assess the effect of acute resistance exercise on appetite hormones (acyl-ghrelin and obestatin) of patients undergoing hemodialysis (HD). Twenty-five patients (44.7 ± 12.9 years, 68% women) on regular HD program were enrolled into two groups, 16 patients performed exercises and 9 patients comprised the control group. The patients performed the exercises in both lower limbs with ankle-cuffs and elastic bands, 30 min after the initiation of hemodialysis session. Blood samples of both the groups were drawn in the morning before and after 30 min with exercise session (exercise group) and, before and after the same time without exercise (control group). Acyl-ghrelin and obestatin plasma levels were measured using an enzyme immunometric assay. Acyl-ghrelin plasma levels did not change in both the groups. However, when stratified by gender the acyl-ghrelin increased significantly right after exercise in men [32.1 pg/mL (25.6-41.2) to 46.0 pg/mL (39.0-59.5)] (p = 0.04). Obestatin plasma levels reduced after a single bout of exercise and changes remained significantly when the sample was stratified by gender. There was no change in obestatin plasma levels in control group. A single bout of resistance exercise seems to modulate the levels of appetite hormones in HD patients.

Fiber type-specific response of skeletal muscle satellite cells to high-intensity resistance training in dialysis patients

INTRODUCTION

The aim of this study was to assess the effect of high-intensity resistance training on satellite cell (SC) and myonuclear number in the muscle of patients undergoing dialysis.

METHODS

Patients (n = 21) underwent a 16-week control period, followed by 16 weeks of resistance training 3 times weekly. SC and myonuclear number were determined by immunohistochemistry of vastus lateralis muscle biopsy cross-sections. Knee extension torque was tested in a dynamometer.

RESULTS

During training, SCs/type I fibers increased by 15%, whereas SCs/type II fibers remained unchanged. Myonuclear content of type II, but not type I, fibers increased with training. Before the control period, the SC content of type II fibers was lower than that of type I fibers, whereas contents were comparable when normalized to fiber area. Torque increased after training.

CONCLUSIONS

Increased myonuclear content of type II muscle fibers of dialysis patients who perform resistance training suggests that SC dysfunction is not the limiting factor for muscle growth.

Effects of resistance exercise training on acyl-ghrelin and obestatin levels in hemodialysis patients

BACKGROUND

Patients undergoing hemodialysis (HD) present altered levels of appetite hormones such as acyl-ghrelin (orexigenic) and obestatin (anorexigenic), which may contribute to anorexia. Physical exercise may affect these hormones and improve appetite in these patients.

OBJECTIVES

The objective of this study is to evaluate the effects of a resistance exercise program in appetite hormones, body composition, and nutritional status in HD patients.

DESIGN

Intervention study with the control group.

SUBJECTS

Fifty-two patients on regular HD program were enrolled into two groups: 37 patients performed exercises (56.7% male, 45 ± 12.8 years, 57 (9-192) months on HD) and 15 patients comprised the control group (66.7% men, 50 ± 10.6 years, 57 (11-153) months on HD).

MEASUREMENTS

Exercise program (performed with elastic bands and ankle cuffs in both lower limbs) was supervised three times a week during 6 months (72 sessions). Patients had their blood drawn in a regular HD day after overnight fasting, before and after 6 months of exercise program. Obestatin, acyl-ghrelin, routine biochemical parameters, quality of life, and anthropometric data were collected and analyzed before and after 6 months.

RESULTS

After 6 months of exercise, obestatin levels reduced [from 3.0 ng/mL (2.3-3.4) to 1.9 ng/mL (0.6-3.4)] and acyl-ghrelin levels increased [from 21.5 pg/mL (1.3-77.7) to 37.2 pg/mL (16.7-94.1)] and the control group presented no significant differences in both plasma levels of hormones. Body composition and physical functional assessed by SF-36 and albumin levels (3.7 ± 0.3 to 3.9 ± 0.2, p < 0.05) improved after exercises.

CONCLUSION

Six months of resistance exercises contributed to changes in plasma appetite hormones, body composition, and nutritional status in hemodialysis patients.

Effect of progressive resistance training on measures of skeletal muscle hypertrophy, muscular strength and health-related quality of life in patients with chronic kidney disease: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Skeletal muscle wasting resulting in reduced muscular strength and health-related quality of life (HR-QOL) is common in chronic kidney disease (CKD) and may be reversed with progressive resistance training (PRT). Therefore, we systematically assessed the effect of PRT on measures of skeletal muscle hypertrophy, muscular strength and HR-QOL in this cohort to inform clinical practice and guidelines.

DESIGN

We performed a systematic review and meta-analysis.

INCLUSION CRITERIA

We included randomised controlled trials (RCTs) that investigated the independent effect of PRT (>6 weeks) on measures of skeletal muscle hypertrophy [muscle mass or cross-sectional area (CSA)], muscular strength and/or HR-QOL in adults with CKD.

DATA EXTRACTION AND ANALYSIS

The standardised mean difference (SMD) from each study was pooled to produce an overall estimate of effect and associated 95% confidence interval (95% CI) between treatment and control groups on primary outcomes.

RESULTS

Seven RCTs in 271 patients with Stage 3-5 CKD yielded seven studies on muscular strength (N = 249), six studies on total body muscle mass (N = 200) and six studies on HR-QOL (N = 223). PRT significantly improved standardised muscular strength [SMD 1.15 (95% CI 0.80-1.49)] and HR-QOL [SMD 0.83 (95% CI 0.51-1.16)], but not total body muscle mass [SMD 0.29 (95% CI -0.27 to 0.86)] in our primary analysis. However, secondary analysis of six studies showed that PRT induced significant muscle hypertrophy of the lower extremities (leg mass, or mid-thigh or quadriceps CSA) [SMD 0.43 (95% CI 0.11-0.76)], a pertinent analysis given that most studies implemented lower-body PRT only.

CONCLUSIONS

Robust evidence from RCTs indicates that PRT can induce skeletal muscle hypertrophy and increase muscular strength and HR-QOL outcomes in men and women with CKD. Therefore, clinical practice guidelines should be updated to inform clinicians on the benefits of PRT in this cohort.

Effect of acute intradialytic strength physical exercise on oxidative stress and inflammatory responses in hemodialysis patients

Background

Oxidative stress and inflammation are common findings in chronic kidney disease (CKD) patients, and they are directly related to the increased risk of developing cardiovascular disease, which is the major cause of death in these patients, particularly for those undergoing hemodialysis (HD). Strength physical exercise is a new therapeutic approach to reduce these complications in CKD patients. Following this, the purpose of this study was to assess the effect of acute intradialytic strength physical exercise on oxidative stress and inflammatory responses in HD patients.

Methods

Sixteen HD patients were studied (11 women; 44.4±14.6 years; body mass index 23.3±4.9 kg/m²; 61.6±43.1 months of dialysis) and served as their own controls. Acute (single session) intradialytic physical exercise were performed at 60% of the one-repetition maximum test for three sets of 10 repetitions for four exercise categories in both lower limbs during 30 minutes. Blood samples were collected on two different days at exactly the same time (30 minutes and 60 minutes after initiating the dialysis—with and without exercise). Antioxidant enzymes activity [superoxide dismutase (SOD), catalase, and glutathione peroxidase], lipid peroxidation marker levels (malondialdehyde), and inflammatory marker levels (high-sensitivity C-reactive protein) were determined.

Results

SOD plasma levels were significantly reduced after acute physical exercise from 244.8±40.7 U/mL to 222.4±28.9 U/mL (P=0.03) and, by contrast, increased on the day without exercise (218.2±26.5 U/mL to 239.4±38.6 U/mL, P=0.02). There was no alteration in plasma catalase, glutathione peroxidase, malondialdehyde, or high-sensitivity C-reactive protein levels in on either day (with or without exercise). Additionally, there was no association between these markers and clinical, anthropometric, or biochemical parameters.

Conclusion

These data suggest that acute intradialytic strength physical exercise was unable to reduce oxidative stress and inflammation, and in addition, it seems to reduce plasma SOD levels, which could exacerbate the oxidative stress in HD patients.

It's a Non-Dialysis Day… Do You Know How Your Patient Is Doing? A Case for Research into Interdialytic Activity

Hemodialysis (HD) patients are less active than their healthy counterparts; this is associated with higher mortality. Healthcare workers observe their patients only during HD, which accounts for about 7% of the week. Knowing more about what occurs in between sessions, particularly with respect to physical activity, may improve patient care and prognosis. Yet without a standard method to measure interdialytic activity, it is difficult to compare the effect of interventions. However, it is unclear how interdialytic activity can be accurately measured. Since activity associated with quality of life is multi-dimensional, objective and subjective tools should be used in conjunction. While commercially available tracking devices can be seamlessly incorporated into everyday life and can increase awareness of user's activity, their validation is needed in the HD population. Fertile topics for research should include the relationship between objective and subjective measures in HD patients, and the investigation of physical activity in non-ambulatory HD patients.