Cardiorespiratory Fitness Is Related to Physical Inactivity, Metabolic Risk Factors, and Atherosclerotic Burden in Glucose-Intolerant Renal Transplant Recipients

Exploring the nexus: The place of kidney diseases within the cardiovascular-kidney-metabolic syndrome spectrum

Cardiovascular-kidney-metabolic (CKM) syndrome and chronic kidney disease (CKD) are two significant comorbidities affecting a large proportion of the general population with considerable crosstalk. In addition to substantial co-incidence of CKD and CKM syndrome in epidemiological studies, clinical and pre-clinical studies have identified similar pathophysiological pathways leading to both entities. Patients with CKM syndrome are more prone to develop acute kidney injury and CKD, while therapeutic alternatives and their success rates are considerably lower in such patient groups. Nevertheless, the association between CKM syndrome and CKD or ESKD is bidirectional rather than being a cause-effect relationship as patients with CKD are also prone to develop peripheral insulin resistance, high blood pressure, and dyslipidemia. Furthermore, such patients are less likely to receive kidney transplantation in addition to the higher allograft dysfunction risk. We hereby aim to evaluate the association in-between kidney diseases and CKM syndrome, including epidemiological data, pre-clinical studies with pathophysiological pathways, and potential therapeutic perspectives.

Physical activity and its impact on cardiovascular health in pediatric kidney transplant recipients

BACKGROUND

Cardiovascular (CV) morbidity after kidney transplantation (KTx) in childhood is of increasing importance. In light of a high prevalence of CV risk factors, protective measures such as physical activity (PA) come into focus. Our aim was to comprehensively assess PA in pediatric KTx recipients and evaluate its impact on CV health.

METHODS

Forty-eight patients were assessed for frequency, duration, intensity, and setting of PA using the "Motorik-Modul" PA questionnaire. Walking-based activity was measured by accelerometer in a subgroup (n = 23). CV risk factors and subclinical CV organ damage were determined. The impact of PA on CV parameters was analyzed using linear regression models.

RESULTS

Fifty-two percent of pediatric KTx recipients did not reach WHO recommended PA level; 54% did not engage in PA with vigorous intensity (VPA). Twenty-nine percent indicated an extremely inactive lifestyle (< 120 min/week of moderate to vigorous intensity PA, MVPA). Compared to the healthy German KiGGS cohort, KTx recipients specifically lacked engagement in sport activities (KTx: 129 min/week; 95%CI, 97-162 vs. KiGGS, 242 min/week; 95%CI, 230-253). VPA was associated with lower systolic blood pressure (p = 0.024) and resting heart rate (p = 0.005), MVPA with fewer components of the post-transplant metabolic syndrome (p = 0.037), and better left ventricular diastolic function (p = 0.006).

CONCLUSIONS

A considerable lack of PA, especially VPA, exists in young KTx recipients. PA was positively associated with important parameters of CV health. While long-term CV protection through PA seems promising in pediatric KTx recipients, specific educational approaches are most likely needed to increase patients' engagement in sport activities.

Cardiopulmonary exercise testing in patients with end-stage kidney disease: principles, methodology and clinical applications of the optimal tool for exercise tolerance evaluation

Chronic kidney disease (CKD), especially end-stage kidney disease (ESKD), is associated with an increased risk for cardiovascular events and all-cause mortality. Exercise intolerance as well as reduced cardiovascular reserve is extremely common in patients with CKD. Cardiopulmonary exercise testing (CPET) is a non-invasive, dynamic technique that provides an integrative evaluation of cardiovascular, pulmonary, neuropsychological and metabolic function during maximal or submaximal exercise, allowing the evaluation of functional reserves of these systems. This assessment is based on the principle that system failure typically occurs when the system is under stress and thus CPET is currently considered to be the gold standard for identifying exercise limitation and differentiating its causes. It has been widely used in several medical fields for risk stratification, clinical evaluation and other applications, but its use in everyday practice for CKD patients is scarce. This article describes the basic principles and methodology of CPET and provides an overview of important studies that utilized CPET in patients with ESKD, in an effort to increase awareness of CPET capabilities among practicing nephrologists.

Metabolic and functional effects of exercise training in diabetic kidney transplant recipients

BACKGROUND

Physical activity levels are significantly lower in kidney transplant (KT) recipients compared to the general population. The effects of exercise training in KT recipients with diabetes mellitus remain unclear, and so little is known about the role of increased exercise on cardiovascular risk and metabolic profile of KT patients.

AIM

To investigate the effects of a 6-mo home-based exercise training program on functional capacity, glucose levels and lipid profile of diabetic KT patients.

METHODS

In total, 21 type II diabetic KT recipients were randomly assigned into two groups: Exercise (n = 11, aged 52.9 ± 10.1 years) and control (n = 10, aged 53.01 ± 9.5 years). All participants at baseline and the end of the study underwent biochemical tests for fasting plasma glucose levels, glycated hemoglobin and lipid profile and cardiopulmonary exercise testing for maximum oxygen uptake [(VO₂)_peak] estimation. The exercise group followed a 6-mo supervised home-based aerobic and progressive resistance exercise program of moderate intensity 3 times per week, while the control group continued to receive usual care.

RESULTS

At the end of the 6-mo study, the exercise group had significantly lower values in fasting plasma glucose by 13.4% (from 120.6 ± 28.9 mg/dL to 104.8 ± 21.9 mg/dL, P = 0.01), glycated hemoglobin by 1.5% (from 6.7% ± 0.4 to 6.6% ± 0.4, P = 0.01) and triglycerides by 8.5% (from 164.7 ± 14.8 mg/dL to 150.8 ± 11.6 mg/dL, P < 0.05) and higher values in high-density lipoprotein by 10.2% (from 51.4 ± 8.8 mg/dL to 57.2 ± 8.7 mg/dL, P < 0.05) and (VO₂)_peak by 4.7% (from 22.7 ± 3.3 to 23.8 ± 4.2, P = 0.02) than the control group. There were statistically significant differences between the two groups at the end of the study for fasting plasma glucose (decreased by 9.6%, P < 0.05), triglycerides (decreased by 4.5%, P = 0.04) and (VO₂)_peak (increased by 4.4%, P = 0.01). Finally, after training, there was a moderate, positive linear relationship between (VO₂)_peak and glycated hemoglobin in the exercise group (r = 0.408, P = 0.03).

CONCLUSION

The results demonstrated that a 6-mo home-based mixed type exercise training program can improve the functional capacity, levels of glucose and lipid profile of diabetic KT recipients.

Longitudinal Follow-Up on Cardiopulmonary Exercise Capacity Related to Cardio-Metabolic Risk Factors in Children With Renal Transplants

Background: Children with chronic kidney disease, including those treated with kidney transplantation (KT), have an increased risk of cardiovascular disease. The aim of this study was to examine the cardiopulmonary exercise capacity after KT compared to matched controls, to relate the results to physical activity, blood pressure and biochemical findings and to follow exercise capacity over time.

Methods: Patients with KT (n = 38, age 7.7–18 years), with a mean time from transplantation of 3.7 years (0.9–13.0) and mean time in dialysis 0.8 years, were examined at inclusion and annually for up to three years. Healthy controls (n = 17, age 7.3–18.6 years) were examined once. All subjects underwent a cardiopulmonary exercise test, resting blood pressure measurement, anthropometry and activity assessment. Patients also underwent echocardiography, dual-energy X-ray absorptiometry (DXA), 24-h ambulatory BP measurements (ABPM), assessment of glomerular filtration rate (GFR) and blood sampling annually.

Results: As compared to healthy controls, KT patients showed decreased exercise capacity measured both as VO_2peak (34.5 vs. 43.9 ml/kg/min, p < 0.001) and maximal load (2.6 vs. 3.5 W/kg, p < 0.0001), similarly as when results were converted to z-scores. No significant difference was found in weight, but the KT patients were shorter and had higher BMI z-score than controls, as well as increased resting SBP and DBP z-scores. The patient or parent reported physical activity was significantly lower in the KT group compared to controls (p < 0.001) In the combined group, the major determinants for exercise capacity z-scores were activity score and BMI z-score (β = 0.79, p < 0.0001 and β = −0.38, p = 0.007, respectively). Within the KT group, low exercise capacity was associated with high fat mass index (FMI), low activity score, low GFR and high blood lipids. In the multivariate analysis FMI and low GFR remained predictors of low exercise capacity. The longitudinal data for the KT patients showed no change in exercise capacity z-scores over time.

Conclusion: Patients with KT showed decreased exercise capacity and increased BP as compared to healthy controls. Exercise capacity was associated to GFR, physical activity, FMI and blood lipids. It did not improve during follow-up.

Exercise training in patients after kidney transplantation

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. Next to the risk of allograft failure, major obstacles for disease-free survival after kidney transplantation include a higher incidence of cancer, infection and cardiovascular events. Risk factors for adverse clinical outcomes include pre-existent comorbidities, the introduction of an immunodeficient status and (lack of) lifestyle changes after transplantation. Indeed, physical inactivity and poor physical fitness are important targets to address in order to improve clinical outcomes after kidney transplantation. This review summarizes the current evidence on exercise training after kidney transplantation, derived from randomized controlled trials. As much as possible, results are discussed in the perspective of the Standardized Outcomes in Nephrology-Transplantation core outcomes, which were recently described as critically important outcome domains for trials in kidney transplant recipients.

Effects of graded exercise training on functional capacity, muscle strength, and fatigue after renal transplantation: a randomized controlled trial

Successful renal transplantation (RT) recipients suffer residual muscle weakness, fatigue, and low functional capacity. A safe, feasible, structured, early graded exercise training to improve functional capacity, muscle strength, and fatigue is the need of the hour. The aim of the study is to assess the effectiveness of graded exercise training on the functional capacity, muscle strength, and fatigue after RT. It is a randomized controlled trial conducted at a tertiary care hospital from January 2012 to December 2016. This trial included 104 consented, stable renal transplant recipients without cardiopulmonary/neuromuscular impairment. They received either routine care (51) or graded exercise training (53) for 12 weeks after randomization. The functional capacity, isometric quadriceps muscle strength, and fatigue score were measured at baseline, six, and 12 weeks later to induction. The outcomes of the study and control groups were analyzed using the /-test, Wilcoxon signed-rank test, ANOVA, and Pearson's correlation. For all analyses, P <0.05 was fixed acceptable. The functional capacity improved by 147 and 255 m, the muscle strength by 6.35 and 9.27 kg, and fatigue score by 0.784 and 1.781 in the control and the study group (SG), respectively, significantly more in the SG. Functional capacity had a positive and negative correlation with muscle strength and fatigue, respectively (P <0.05). The graded exercise training significantly improved the functional capacity, fatigue levels, and muscle strength after RT.

Obesity and Metabolic Syndrome in Kidney Transplantation: The Role of Dietary Fructose and Systemic Endotoxemia

BACKGROUND

The concepts that obesity is merely a consequence of overeating, and that metabolic health then reflects obesity, may be insufficient and potentially flawed. The role of fructose intake and metabolic endotoxemia has gained attention recently, but data in kidney transplantation are lacking. This study evaluated the risk factors for metabolic syndrome (MS), its components, and other associated markers in kidney transplant recipients (KTRs), focusing particularly on fructose intake and systemic endotoxemia.

METHODS

This cross-sectional observational study enrolled 128 KTRs longer than 1 year posttransplantation. Clinical, biochemical, anthropometric, and questionnaire assessments were undertaken.

RESULTS

Obesity (body mass index, ≥30 kg/m) and MS (International Diabetes Federation Definition) were found in 36.7% and 50% of KTRs, respectively. Both increased fructose intake (P = 0.01) and endotoxin level (P = 0.02) were independently associated with MS; and higher fructose intake was independently associated with obesity (P < 0.001). Specifically, increased fructose intake was associated with the central obesity (P = 0.01) and hyperglycemia (P < 0.001) criteria of MS, whereas higher endotoxin level was associated with the hypertriglyceridemia (P = 0.003) and low HDL cholesterol concentration (P = 0.002) criteria of MS. Neither saturated fat nor total caloric intakes were independently associated with obesity and MS; and neither obesity nor central obesity were independently associated with the dyslipidemia and hyperglycemia criteria of MS. Principal component analysis demonstrated relationships between higher levels of endotoxin, soluble endothelial selectin, triglycerides, and insulin resistance (r > 0.6), as well as relationships between increased fructose intake, inflammation, and blood glucose (r > 0.6).

CONCLUSIONS

Dietary modifications through decreasing fructose intake and addressing systemic endotoxemia are plausible targets for improving metabolic health of KTRs.

Physical Activity in Kidney Transplant Recipients: A Review

Physical activity has known health benefits and is associated with reduced cardiovascular risk in the general population. Relatively few data are available for physical activity in kidney transplant recipients. Compared to the general population, physical activity levels are lower overall in kidney recipients, although somewhat higher compared to the dialysis population. Recipient comorbid condition, psychosocial and socioeconomic factors, and long-term immunosuppression use negatively affect physical activity. Physical inactivity in kidney recipients may be associated with reduced quality of life, as well as increased mortality. Interventions such as exercise training appear to be safe in kidney transplant recipients and are associated with improved quality of life and exercise capacity. Additional studies are required to evaluate long-term effects on cardiovascular risk factors and ultimately cardiovascular disease outcomes and patient survival. Currently available data are characterized by wide variability in the interventions and outcome measures investigated in studies, as well as use of small sample-sized cohorts. These limitations highlight the need for larger studies using objective and standardized measures of physical activity and physical fitness in kidney transplant recipients.

The association among three aspects of physical fitness and metabolic syndrome in a Korean elderly population

BACKGROUND

The purpose of current study is to evaluate the association between physical fitness level and the prevalence of metabolic syndrome (MS) in a Korean elderly population.

METHODS

A cross-sectional study measuring physical fitness and components of MS in a health promotion center of a general hospital for routine health check-ups. A total of 227 subjects >60 years old agreed to participate. A lifestyle questionnaire that included cigarette smoking, alcohol consumption, and physical activity was checked. Body weight, height, blood pressure, fasting glucose, total cholesterol, triglycerides, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, C-reactive protein, and glycated hemoglobin were measured. Muscular strength was assessed by measuring grasping power. Muscular endurance was evaluated using a sit-up test. Cardiopulmonary fitness was assessed via the Tecumseh step test (measuring hear rates at 1 min post-exercise).

RESULTS

The highest tertile muscular endurance group (sit-ups >15 in men, >10 in women) was 0.37 times less likely to have MS [95 % confidence interval (CI) 0.17-0.84; p = 0.036] compared to that in the lowest tertile group (<11 in men, 0 in women), and the highest tertile in the cardiopulmonary fitness group (heart rate at rest >91/min in men, >92/min in women) was 2.81 times more likely to have MS (95 % CI 1.27-6.18; p = 0.038) compared to that in the lowest tertile group (<81/min in men, <80/min in women).

CONCLUSIONS

Cardiopulmonary fitness and muscular endurance were related to MS in a Korean elderly population after adjusting for age, sex, current smoker, current alcohol drinking, and physical activity. Older adults should be encouraged to increase their cardiopulmonary fitness and muscular endurance.

Physical activity and renal transplantation

Renal transplantation is burdened by high cardiovascular risk because of increased prevalence of traditional and disease-specific cardiovascular risk factors and, consequently, patients are affected by greater morbidity and mortality. In renal transplanted patients, healthy lifestyle and physical activity are recommended to improve overall morbidity and cardiovascular outcomes. According to METs (Metabolic Equivalent Task; i.e. the amount of energy consumed while sitting at rest), physical activities are classified as sedentary (<3.0 METs), of moderate-(3.0 to 5.9 METs) or vigorous-intensity (≥ 6.0 METs). Guidelines suggest for patients with chronic kidney disease an amount of physical activity of at least 30 minutes of moderate-intensity activity five times per week (min 450 MET-minutes/week). Data on physical activity in renal transplanted patients, however, are limited and have been mainly obtained by mean of non-objective methods. Available data suggest that physical activity is low either at the start or during renal transplantation and this may be associated with poor patient and graft outcomes. Therefore, in renal transplanted patients more data on physical activity obtained with objective, accelerometer-based methods are needed. In the meanwhile, physical activity have to be considered as an essential part of the medical care for renal transplanted recipients.

Obesity, metabolic syndrome and diabetes mellitus after renal transplantation: prevention and treatment

The prevalence of the metabolic syndrome in dialysis patients is high and further increases after transplantation due to weight gain and the detrimental metabolic effects of immunosuppressive drugs. Corticosteroids cause insulin resistance, hyperlipidemia, abnormal glucose metabolism and arterial hypertension. The calcineurin inhibitor tacrolimus is diabetogenic by inhibiting insulin secretion, whereas cyclosporine causes hypertension and increases cholesterol levels. Mtor antagonists are responsible for hyperlipidemia and abnormal glucose metabolism by mechanisms that also implicate insulin resistance. The metabolic syndrome in transplant recipients has numerous detrimental effects such as increasing the risk of new onset diabetes, cardiovascular disease events and patient death. In addition, it has also been linked with accelerated loss of graft function, proteinuria and ultimately graft loss. Prevention and management of the metabolic syndrome are based on increasing physical activity, promotion of weight loss and control of cardiovascular risk factors. Bariatric surgery before or after renal transplantation in patients with body mass index >35 kg/m(2) is an option but its long term effects on graft and patient survival have not been investigated. Steroid withdrawal and replacement of tacrolimus with cyclosporine facilitate control of diabetes, whereas replacement of cyclosporine and mtor antagonists can improve hyperlipidemia. The new costimulation inhibitor belatacept has potent immunosuppressive properties without metabolic adverse effects and will be an important component of immunosuppressive regimens with better metabolic risk profile. Medical treatment of cardiovascular risk factors has to take potential drug interactions with immunosuppressive medication and drug accumulation due to renal insufficiency into account.

Exercise limitation following transplantation

Organ transplantation is one of the medical miracles or the 20th century. It has the capacity to substantially improve exercise performance and quality of life in patients who are severely limited with chronic organ failure. We focus on the most commonly performed solid-organ transplants and describe peak exercise performance following recovery from transplantation. Across all of the common transplants, evaluated significant reduction in VO2peak is seen (typically renal and liver 65%-80% with heart and/or lung 50%-60% of predicted). Those with the lowest VO2peak pretransplant have the lowest VO2peak posttransplant. Overall very few patients have a VO2peak in the normal range. Investigation of the cause of the reduction of VO2peak has identified many factors pre- and posttransplant that may contribute. These include organ-specific factors in the otherwise well-functioning allograft (e.g., chronotropic incompetence in heart transplantation) as well as allograft dysfunction itself (e.g., chronic lung allograft dysfunction). However, looking across all transplants, a pattern emerges. A low muscle mass with qualitative change in large exercising skeletal muscle groups is seen pretransplant. Many factor posttransplant aggravate these changes or prevent them recovering, especially calcineurin antagonist drugs which are key immunosuppressing agents. This results in the reduction of VO2peak despite restoration of near normal function of the initially failing organ system. As such organ transplantation has provided an experiment of nature that has focused our attention on an important confounder of chronic organ failure-skeletal muscle dysfunction.

Exercise training improves aerobic capacity, muscle strength, and quality of life in renal transplant recipients

Renal transplant recipients (RTR) have reduced peak aerobic capacity, muscle strength, arterial function and an unfavorable cardiovascular disease risk (CVD) profile. This study compared the effects of 12 weeks of supervised endurance and strength training (EST, n = 16) versus usual care (UC, n = 15) on peak aerobic capicity, cardiovascular and skeletal muscle function, CVD risk profile, and quality of life (QOL) in RTR (55 ± 13 years). Peak aerobic capacity and exercise hemodynamics, arterial compliance, 24-h blood pressure, muscle strength, lean body mass, CVD risk score, and QOL were assessed before and after 12 weeks. The change in peak aerobic capacity (EST: 2.6 ± 3.1 vs. UC: -0.5 ± 2.5 mL/(kg·min)), cardiac output (EST: 1.7 ± 2.6 vs. UC: -0.01 ± 0.8 L/min), leg press (EST: 48.7 ± 34.1 vs. UC: -10.5 ± 37.7 kg) and leg extension strength (EST: 9.5 ± 10.3 vs. UC: 0.65 ± 5.5 kg) improved significantly after EST compared with UC. The overall change in QOL improved significantly after 12 weeks of EST compared with UC. No significant difference was found between groups for lean body mass, arterial compliance, 24-h blood pressure or CVD risk score. Supervised EST is an effective intervention to improve peak exercise aerobic capacity and cardiac output, muscle strength and QOL in clinically stable RTR.

Physical activity and physical fitness in lymphoma patients before, during, and after chemotherapy: a prospective longitudinal study

Fatigue is a common and distressing symptom in cancer patients, especially in lymphoma patients. One hypothesized mechanism in the etiology of fatigue is a vicious circle between fatigue, physical inactivity, and deconditioning. However, the natural evolution of physical activity and physical fitness over the course of treatment is unknown. Therefore, the aim of this longitudinal study was to assess fatigue, physical activity, and physical fitness in lymphoma patients before, during, and after treatment. Fatigue was measured with the EORTC-QLQ-C30, physical activity with an accelerometer, and physical fitness with a maximal incremental cycle ergometer test, 6-min walking distance test, and muscle strength measurements. Differences between the three measurement moments and baseline differences between Hodgkin lymphoma and non-Hodgkin lymphoma, early and advanced disease, were analyzed. Twenty-nine patients were included. Functional exercise capacity and quadriceps force were impaired before the start of treatment (86 ± 15 and 82 ± 16 % of predicted value, respectively). Over the course of treatment, significant declines were found in hemoglobin, quadriceps force, handgrip force, and maximal oxygen uptake, while patients reported more fatigue (p values < 0.016). Fatigue was significantly correlated with hemoglobin (r = -0.49), physical activity (r = 0.81), and physical functioning (r = -0.44). Large interindividual variations were found. The present study partially confirmed the hypothesized vicious circle between fatigue, physical inactivity, and deconditioning. Further research with larger samples and longer follow-up is needed to identify factors associated with individual variation in the evolution of fatigue, physical activity, and physical fitness.

Cardiopulmonary fitness is independently associated with insulin resistance in non-diabetes mellitus patients of a university hospital in Korea

Background

Insulin resistance, decreased response of peripheral tissue to normal insulin levels, is known to be related to cardiometabolic diseases. Cardiopulmonary fitness is also considered to be related to these comorbidities. Therefore, we investigated the relationship between insulin resistance and cardiopulmonary fitness by performing a 3-minute step test in a Korean non-diabetes mellitus (DM) population.

Methods

A total of 118 non-DM subjects were enrolled during their routine health check-up. Insulin resistance was measured by calculating homeostatic model assessment-insulin resistance (HOMA-IR), and a 3-minute step test was performed to measure cardiopulmonary fitness.

Results

Post-60 seconds exercise heart rate after 3-minute test (R60 heart rate) was correlated with age (r = -0.21, P = 0.02), education (r = 0.17, P = 0.04), body mass index (r = 0.23, P = 0.01), waist circumference (r = 0.28, P < 0.01), fasting insulin (r = 0.28, P < 0.01), HOMA-IR (r = 0.25, P < 0.01), low density lipoprotein-cholesterol (r = 0.28, P < 0.01), high sensitivity C-reactive protein levels (r = 0.22, P = 0.02), and baseline heart rate (r = 0.56, P < 0.01). In a step-wise multiple regression analysis, baseline heart rate (β = 0.79, P < 0.001), HOMA-IR (β = 0.65, P = 0.02), and systolic blood pressure (β = 0.15, P = 0.03) were identified as explanatory variables for R60 heart rates.

Conclusion

Our results suggested that cardiopulmonary fitness was associated with insulin resistance in non-DM patients of a university hospital in Korea. Further studies are needed to elucidate the underlying mechanisms.

A randomized controlled trial of exercise training on cardiovascular and autonomic function among renal transplant recipients

BACKGROUND

There are conflicting data regarding the effects of renal transplantation (RT) on uraemic autonomic dysfunction. Moreover, no study has examined the impact of physical training on the cardiac autonomic function in RT patients. Thus, we studied the effects of exercise training on heart rate variability (HRV) and arterial baroreflex sensitivity (BRS), which are sensitive markers of cardiac autonomic outflow, in RT recipients.

METHODS

Eleven patients (Exercise group-aged 52.1 ± 5.6 years) were studied before and after 6 months of exercise training. Twelve age- and sex- matched RT patients (Sedentary) and 12 healthy sedentary individuals (Healthy), who remained untrained, served as controls. At baseline and follow-up, all the subjects underwent cardiopulmonary exercise testing for the evaluation of peak oxygen consumption (VO2peak), a tilt test for the evaluation of BRS and baroreflex effectiveness index (BEI) and an ambulatory 24-h Holter monitoring for time- and frequency-domain measures of HRV.

RESULTS

In the exercise group, VO2peak increased by 15.8% (P < 0.05) and all depressed HRV and BRS indices were significantly improved after training. Specifically, the standard deviation of all normal-to-normal (NN) intervals (SDNN) significantly increased by 92.5%, the root-mean-square of the differences between consecutive NN intervals by 45.4%, the percentage value of NN50 count by 58.2%, the high-frequency by 74.8% and low-frequency spectral power by 41.6%, BRS by 43.7% and BEI by 57.3%. None of the variables studied was altered over time in either control group.

CONCLUSIONS

The increased cardiorespiratory fitness by exercise training was associated with an improved BRS function and a modification of the sympathovagal control of HRV towards a persistent increase in parasympathetic tone. These alterations may lead to a better cardiovascular prognosis in RT recipients.

Effects of exercise in renal transplant recipients

Even after a successful renal transplantation, the renal transplant recipients (RTRs) keeps on suffering the consequences of the uremic sickness. Cardiovascular risk, work capacity, and quality of life do not improve according to expectations since biological and psychological problems are not completely solved by pharmacological treatment. Furthermore, post-transplant treatment, per se, induces additional problems (i.e., side effects of drugs). It becomes, indeed, very important to insert “non-pharmacological” therapies able to reverse this trend. Exercise may represent an important contribution in the solution of this problem. In fact, many studies have demonstrated, in the last two decades, that physical training is able both, to improve graft function, work capacity and quality of life, and to reduce cardiovascular risk. In conclusion, if the analysis of the available data suggests that an appropriate dose of physical training represent a useful, safe and non-pharmacologic contribution to RTR treatment, it becomes a kidney transplantologist responsibility to introduce exercise in the current therapy of RTRs.

Independent beneficial effects of aged garlic extract intake with regular exercise on cardiovascular risk in postmenopausal women

The purpose of the study was to assess the effects of a 12 weeks aged garlic extract (AGE) regimen with regular exercise on cardiovascular disease (CVD) risk in postmenopausal women. A total of 30 postmenopausal women (54.4 ± 5.4 years) were randomly divided into the following four groups: Placebo (Placebo; n = 6), AGE intake (AGEI; n = 8), exercise and placebo (Ex + Placebo; n = 8), exercise and AGE (Ex + AGE; n = 8) groups. The AGE group consume 80 mg per day, and exercise groups performed moderate exercise (aerobic and resistance) three times per week. After 12 weeks of treatment, body composition, lipid profile, and CVD risk factors were analyzed. Body weight was significantly decreased in AGEI, Ex + Placebo, and Ex + AGE groups compared to baseline. Body fat % was significantly decreased in the AGEI and Ex + Placebo groups. Body mass index (BMI) was significantly decreased in the AGEI, Ex + Placebo, and Ex + AGE groups. Fat-free mass was significantly decreased in the AGEI group. Total cholesterol (TC) was significantly lower in the Ex + Placebo compared to the Placebo group. AGE supplementation or exercise effectively reduced low-density lipoprotein (LDL-C). Triglyceride (TG) was significantly increased in the AGEI group. Malondialdehyde (MDA) levels were significantly decreased in the AGEI, Ex + Placebo, and Ex + AGE compared to the placebo group. AGE supplementation reduced homocysteine levels regardless of whether the women also exercised. The present results suggest that AGE supplementation reduces cardiovascular risk factors independently of exercise in postmenopausal women.

Cardiorespiratory fitness in young adults with a history of renal transplantation in childhood

Limited knowledge exists on cardiorespiratory fitness (CR fitness) in adults having a renal transplant (Rtx) during childhood. Our aim was to assess CR fitness (V0(2peak)) with a maximal treadmill test in former Rtx children reaching adulthood (ped-tx, n = 31), compared to patients Rtx as adults (adult-tx, n = 17) and healthy controls (HC, n = 36). Median age was 26.9 (19-41), 28.6 (23.5-34) and 33.5 (20-42) years, respectively. Median time since first Rtx was 18.1 (7-29) and 3.7 (1.2-12.6) years. Body composition was measured by dual-energy X-ray absorptiometry (DXA). V0(2peak) was median 37.9 (12.5-56.3), 40.8 (26.5-57.5), and 44.4 (29.5-65.6) ml kg (-1)min (-1) in the ped-tx, adult-tx, and HC, respectively. Ped-tx had significantly lower V0(2peak) compared to HC (p = 0.01). Adult-tx had higher exercise capacity (test duration) compared to ped-tx (median 10.5 (7.5-16) and 9 (6-14) min, respectively (p = 0.016). In multiple linear regression analysis, test duration, fat-free mass (FFM, kg) and Hgb (g/dl) were significant predictors of V0(2peak) explaining 86% of its variance. There was no significant difference between ped-tx and adult-tx in V0(2peak.) CR fitness depicts long-term health outcome in Rtx patients both in regard to physical functioning and is a plausible indirect marker of CV health.

Evaluation of dietetic advice for modification of cardiovascular disease risk factors in renal transplant recipients

OBJECTIVE

To investigate the effect of dietitian involvement in a multidisciplinary lifestyle intervention comparing risk factor modification for cardiovascular disease with standard posttransplant care in renal transplant recipients (RTR) with abnormal glucose tolerance (AGT).

DESIGN

Randomized controlled trial.

SETTING

Hospital outpatient department.

PATIENTS

Adult RTR with AGT.

INTERVENTION

RTR with AGT were randomized to a lifestyle intervention that consisted of either regular consultations with the dietitian and multidisciplinary team or standard care.

MAIN OUTCOME MEASURES

Dietary intake, physical activity (PA) levels, cardiorespiratory fitness (CF), and anthropometry.

RESULTS

Total fat and percent saturated fat intake rates were significantly lower in the intervention group as compared with the control group at 2-year follow-up, 54 g (16 to 105 g) versus 65 g (34 to 118 g), P = .01 and 10% (5% to 17%) versus 13% (4% to 20%), P = .05., respectively. There was a trend for an overweight (but not obese) individual to lose more weight in the intervention group (4% loss vs. a gain of 0.25% at the 2-year follow-up). Overall, RTR were significantly less fit than age- and gender-matched controls, mean peak oxygen uptake was 19.42 ± 7.09 mL/kg per minute versus 28.35 ± 8.80 mL/kg per minute, P = .000. Simple exercise advice was not associated with any improvement in total PA or CF in either group at the 2-year follow-up.

CONCLUSION

Dietary advice can contribute to healthier eating habits and a trend for weight loss in RTR with AGT. These improvements in conjunction with multidisciplinary care and pharmacological treatment can lead to improvements in cardiovascular risk factors such as lipid profile. Simple advice to increase PA was not effective in improving CF and other measures are needed.

Metabolic syndrome and solid-organ transplantation

The metabolic syndrome is proposed as a cluster of known cardiovascular risk factors, interrelated by a common pathophysiological defect, that symbolize a heightened metabolic burden. Advocates of the concept argue that it is a predictor for both diabetes and cardiovascular disease, complications of great importance posttransplantation. The abundant medical literature on the topic is now expanding into the field of transplantation with evidence linking the metabolic syndrome to adverse patient and graft outcomes. Although the implications posttransplantation are significant, controversy surrounds the concept and the topic has not previously been reviewed in the context of solid-organ transplantation. The purpose of this review is to update transplant clinicians with our current understanding of the metabolic syndrome, review the transplantation literature and examine the controversies surrounding the concept.

Kidney transplantation: a systematic review of interventional and observational studies of physical activity on intermediate outcomes

Kidney transplant patients have decreased quality and longevity of life. Whether exercise can positively affect associated outcomes such as physical functioning, metabolic syndrome, kidney function, and immune function, has only been addressed in relatively small studies. Thus the aim of this systematic review was to determine effects of physical activity level on these intermediate outcomes in kidney transplant patients. We electronically and hand searched to identify 21 studies (6 retrospective assessments of habitual physical activity and 15 intervention studies including 6 controlled trials). After study quality assessment, intermediate outcomes associated with quality and longevity of life were expressed as correlations or percentage changes in addition to effect sizes. Habitual physical activity level was positively associated with quality of life and aerobic fitness and negatively associated with body fat (medium to large effect sizes). Exercise interventions also showed medium to large positive effects on aerobic capacity (10%-114% increase) and muscle strength (10%-22% increase). However, exercise programs had minimal or contradictory effects on metabolic syndrome and immune and kidney function. In kidney transplant patients, physical activity intervention is warranted to enhance physical functioning. Whether exercise impacts on outcomes associated with longevity of life requires further study.

Exercise capacity and body composition in living-donor renal transplant recipients over time

BACKGROUND

Renal transplantation (RTx) restitutes the function of the failing organ and induces convalescence of the entire organism. Our study investigates whether this is accompanied by improvements in cardiovascular function and structural changes.

METHODS

A total of 25 Caucasian patients (14 male, median age 44.2 +/- 9.2 years, BMI 23.7 +/- 4.0 kg/m(2)) were assessed in a prospective trial before, 1, 3 and 12 months after RTx from living donors by clinical examination, cardiopulmonary exercise testing, dual X-ray absorptiometry (DEXA) and analysis of plasma indices.

RESULTS

Creatinine clearance improved from 8.0 +/- 3.1 to 60.9 +/- 18.1 mL/min at 1 month, but declined at 3 (51.6 +/- 16.3 mL/min) and 12 months (53.6 +/- 20.8 mL/min, P = 0.04 versus month 1). Body composition shifted from lean towards fat tissue (25.8 +/- 12.5-31.2 +/- 11.2% body fat content, P = 0.0001). Only baseline lean weight correlated with fat increase over time (r(2) = 0.28, P = 0.008). Patients with fat content above median (n = 13) had a 3-fold increased hazard ratio of infection (CI 1.04-9.41, P = 0.042) and overall hospitalization (hazard ratio 2.95, CI 1.10-7.93, P = 0.03). PeakVO(2) decreased over RTx (23.2 +/- 6.0- 17.6 +/- 5.1 mL/kg/min) and returned to baseline levels not until 1 year later (P < 0.001). After an initial decline, muscle oxidative capacity (peakVO(2)/lean mass) improved from 33.6 +/- 10.1 to 35.0 +/- 8.2 mL/kg/min at 12 months after RTx (P < 0.001).

CONCLUSIONS

After RTx, body composition shifted continuously towards fat tissue, and baseline lean weight significantly correlated with fat increase over time. Both severe infections and hospitalizations are associated with a higher fat content before RTx. Exercise capacity (peakVO(2)) worsened after RTx and restitutes during follow-up, with muscle quality (peakVO(2)/lean) even exceeding baseline levels after 12 months.