Circulating irisin levels are positively associated with endothelium-dependent vasodilation in newly diagnosed type 2 diabetic patients without clinical angiopathy

Objective

Irisin is a newly identified myokine that can promote energy expenditure and alleviate insulin-resistance in animal model. It has been established that insulin resistance is frequently associated with endothelial dysfunction. Therefore, we hypothesize that circulating irisin levels are associated with endothelial dysfunction in type 2 diabetes.

Methods

One hundred and eighty eight patients with newly diagnosed type 2 diabetes and 40 healthy subjects were recruited. Serum irisin concentrations were measured by using enzyme-linked immunosorbent assay, and flow-mediated dilation (FMD) was evaluated by using high-resolution ultrasound.

Results

The mean value of circulating irisin levels in newly diagnosed type 2 diabetes was 13.25 ng/ml, which was significantly lower than that in controls (25.98 ng/ml, p < 0.001). By dividing the distribution of FMD levels into quartiles, serum irisin levels were increased gradually with the increase of FMD levels (p < 0.001). Multivariate stepwise regression analysis demonstrated that serum irisin levels were independently associated with FMD (p = 0.009). By logistic regression analysis the odds ratio for lower FMD levels was reduced by 11.8% per 1 ng/ml increase in serum irisin concentration after adjustment for multivariate metabolic factors [OR (95% CI); 0.882 (0.709–0.969)].

Conclusion

These results demonstrated that circulating irisin levels were decreased in newly diagnosed Chinese type 2 diabetic patients without clinical angiopathy and positively associated with FMD levels.     

Circulating Follistatin in Patients with Chronic Kidney Disease: Implications for Muscle Strength,Bone Mineral Density,Inflammation, and Survival

Summary

Background and objectives

Follistatin mediates muscle growth and bone mineralization. At present, it is unknown whether circulating follistatin levels are altered in chronic kidney disease (CKD) or links to CKD risk factors and outcomes.

Design, setting, participants, & measurements

Plasma follistatin levels were cross-sectionally analyzed in relation to protein-energy wasting (PEW), handgrip strength (HGS), bone mineral density (BMD), and inflammatory markers in 280 CKD stage 5 patients, 32 CKD stage 4 patients, 16 CKD stage 3 patients, and 32 control subjects. In CKD stage 5 patients survival was prospectively investigated during a follow-up period of up to 5 years.

Results

The plasma follistatin concentration was not higher in CKD stage 5 patients than in other CKD stages or controls. In CKD stage 5 patients, circulating follistatin positively correlated with age, high-sensitivity C-reactive protein (hsCRP), and IL-6; negatively correlated with HGS, serum creatinine, and BMD; and was increased in patients with PEW. In a multivariate logistic regression model, lower HGS, lower BMD, and higher hsCRP independently correlated with higher follistatin levels. In a Cox regression model, follistatin levels were not associated with all-cause mortality.

Conclusions

Circulating follistatin levels were neither elevated nor predicted outcome in patients with CKD. However, increased follistatin levels occurred together with increased inflammation, reduced muscle strength, and low BMD, suggesting an involvement of a mechanism including follistatin in the uremic wasting process.     

Novel adipokines vaspin and irisin as risk biomarkers for cardiovascular diseases in type 2 diabetes mellitus

Aims

Vaspin and irisin are novel cytokines proposed as potential new biomarkers of insulin resistance and endothelial dysfunction. This work is to investigate circulating levels of vaspin and irisin in patients with type 2 diabetes mellitus (T2DM) with and without cardiovascular disease (CVD) to study potential association with disease risk.

Circulating adiponectin levels and risk of type 2 diabetes in the Japanese

Background:

Adiponectin has anti-inflammatory and insulin-sensitizing properties. Prospective studies have consistently shown a lower risk of type 2 diabetes among those with higher circulating adiponectin levels.

Objective:

We examined prospectively the association between serum adiponectin levels and type 2 diabetes risk among Japanese workers, taking visceral fat mass into account.

Subjects and methods:

Subjects were 4591 Japanese employees who attended a comprehensive health screening in 2008; had biochemical data including serum adiponectin; were free of diabetes at baseline; and received health screening in 2011. Multiple logistic regression analysis was used to examine the association between adiponectin and incidence of diabetes among overall subjects, as well as subgroups. Stratified analyses were carried out according to variables including visceral fat area (VFA).

Results:

During 3 years of follow-up, 217 diabetic cases were newly identified. Of these, 87% had a prediabetes at baseline. Serum adiponectin level was significantly, inversely associated with incidence of diabetes, with odds ratios (95% confidence interval) adjusted for age, sex, family history, smoking, alcohol drinking, physical activity and body mass index (BMI) for the lowest through highest quartile of adiponectin of 1 (reference), 0.79 (0.55–1.12), 0.60 (0.41–0.88) and 0.40 (0.25–0.64), respectively (P-value for trend <0.01). This association was materially unchanged with adjustment for VFA instead of BMI. After further adjustment for both homeostasis model assessment of insulin resistance and hemoglobin A1c, however, the association became statistically nonsignificant (P-value for trend=0.18). Risk reduction associated with higher adiponectin levels was observed in both participants with and without obesity or insulin resistance at baseline.

Conclusions:

Results suggest that higher levels of circulating adiponectin are associated with a lower risk of type 2 diabetes, independently of overall and intra-abdominal fat deposition, and that adiponectin may confer a benefit in both persons with and without insulin resistance.     

High irisin levels in overweight/obese children and its positive correlation with metabolic profile,blood pressure,and endothelial progenitor cells

Background and aims

Irisin is involved in the compensatory mechanisms for metabolic regulation and appears to be associated with glucose homeostasis and lipid profile. However, it's possible implications on obesity-associated cardiometabolic complications have not been completely elucidated. This study aimed to investigate the association between irisin level and anthropometric data, metabolic parameters, blood pressure, and endothelial progenitor cells (EPCs) level among children with overweight/obesity.

Plasma amino acid profiles are associated with insulin,C-peptide and adiponectin levels in type 2 diabetic patients

Objectives:

Plasma-free amino acid (PFAA) profiles have been associated with a future risk of developing diabetes or cardiovascular disease in nondiabetic subjects. These PFAA alterations might predominantly result from the metabolic shift caused by insulin resistance and visceral fat deposition. The variety of PFAA profiles within diabetic subjects is not well researched. In this study, we focused on type 2 diabetic subjects and examined the association between PFAA profiles and insulin- and glucose-related variables.

Methods:

Fifty-one Japanese subjects diagnosed with type 2 diabetes were recruited from an outpatient clinic. The plasma concentrations of 21 amino acids; glucose-related markers including glucose, hemoglobin A1c (HbA1c), glycoalbumin and 1,5-anhydroglucitol; insulin-related markers including insulin, C-peptide, and the homeostasis model assessment of insulin resistance; and adipocytokines including adiponectin and leptin were determined. The association of PFAA and other metabolic profiles were analyzed, and stratified analyses of the PFAAs and clinical characteristics were performed according to the fasting plasma insulin and HbA1c levels. In addition, the PFAA indices that correlate to visceral fat obesity were evaluated.

Results:

Although strong correlations between PFAAs and glucose-related markers were not observed, several amino acids (branched-chain amino acids, tryptophan, alanine, tyrosine, glutamate and proline) and PFAA indices that evaluate visceral obesity were highly correlated with insulin-related markers and adiponectin (P<0.001). In the group of diabetic patients with hyperinsulinemia, the amino acid levels were significantly increased, which generally demonstrated good concordance with insulin-related markers and adiponectin levels.

Conclusions:

The PFAA profiles in diabetic patients were strongly associated with hyperinsulinemia and hypoadiponectinemia, which might become risk evaluation factors for the development of cardiovascular diseases.     

Neutrophil Gelatinase-Associated Lipocalin as an Early Sign of Diabetic Kidney Injury in Children

Objective:

There is some evidence indicating that histopathological changes in type 1 diabetes mellitus (T1DM) emerge before onset of microalbuminuria. The aim of our study was to determine whether urine neutrophil gelatinase-associated lipocalin (NGAL) levels can be considered as an early sign of diabetic kidney injury.

Methods:

Urine NGAL (uNGAL) levels and urinary NGAL/creatinine ratio (uNGAL/Cr) were assessed in 76 patients with T1DM and compared with the findings of 35 healthy individuals. The relationship of uNGAL levels with diabetes duration, body mass index (BMI), serum lipids, HbA1c, and microalbuminuria was also evaluated.

Results:

Mean uNGAL (100.16±108.28 ng/mL) and uNGAL/Cr (118.93-117.97 ng/mg) levels in both microalbuminuric and non-microalbuminuric diabetic patients were found to be higher than those in the control group (uNGAL: 21.46±18.59 ng/mL and uNGAL/Cr: 32.1±51.48 ng/mg) (p=0.0001).

Conclusion:

Urine NGAL level increases in the very early phase of T1DM before microalbuminuria develops. The patients with T1DM should be considered to have diabetic kidney injury from the time of diagnosis on and preventive interventions need to be initiated at an early stage to preclude the progression to end-stage renal disease.     

Nonlinear Methods to Assess Changes in Heart Rate Variability in Type 2 Diabetic Patients

Background

Heart rate variability (HRV) is an important indicator of autonomic modulation of cardiovascular function. Diabetes can alter cardiac autonomic modulation by damaging afferent inputs, thereby increasing the risk of cardiovascular disease. We applied nonlinear analytical methods to identify parameters associated with HRV that are indicative of changes in autonomic modulation of heart function in diabetic patients.

Objective

We analyzed differences in HRV patterns between diabetic and age-matched healthy control subjects using nonlinear methods.

Methods

Lagged Poincaré plot, autocorrelation, and detrended fluctuation analysis were applied to analyze HRV in electrocardiography (ECG) recordings.

Results

Lagged Poincare plot analysis revealed significant changes in some parameters, suggestive of decreased parasympathetic modulation. The detrended fluctuation exponent derived from long-term fitting was higher than the short-term one in the diabetic population, which was also consistent with decreased parasympathetic input. The autocorrelation function of the deviation of inter-beat intervals exhibited a highly correlated pattern in the diabetic group compared with the control group.

Conclusion

The HRV pattern significantly differs between diabetic patients and healthy subjects. All three statistical methods employed in the study may prove useful to detect the onset and extent of autonomic neuropathy in diabetic patients.     

Urinary Creatinine Excretion,Bioelectrical Impedance Analysis,and Clinical Outcomes in Patients with CKD: The CRIC Study

Background and objectives

Previous studies in chronic disease states have demonstrated an association between lower urinary creatinine excretion (UCr) and increased mortality, a finding presumed to reflect the effect of low muscle mass on clinical outcomes. Little is known about the relationship between UCr and other measures of body composition in terms of the ability to predict outcomes of interest.

Design, setting, participants, & measurements

Using data from the Chronic Renal Insufficiency Cohort (CRIC), the relationship between UCr, fat free mass (FFM) as estimated by bioelectrical impedance analysis, and (in a subpopulation) whole-body dual-energy x-ray absorptiometry assessment of appendicular lean mass were characterized. The associations of UCr and FFM with mortality and ESRD were compared using Cox proportional hazards models.

Results

A total of 3604 CRIC participants (91% of the full CRIC cohort) with both a baseline UCr and FFM measurement were included; of these, 232 had contemporaneous dual-energy x-ray absorptiometry measurements. Participants were recruited between July 2003 and March 2007. UCr and FFM were modestly correlated (rho=0.50; P<0.001), while FFM and appendicular lean mass were highly correlated (rho=0.91; P<0.001). Higher urinary urea nitrogen, black race, younger age, and lower serum cystatin C level were all significantly associated with higher UCr. Over a median (interquartile range) of 4.2 (3.1–5.0) years of follow-up, 336 (9.3%) participants died and 510 (14.2%) reached ESRD. Lower UCr was associated with death and ESRD even after adjustment for FFM (adjusted hazard ratio for death per 1 SD higher level of UCr, 0.63 [95% confidence interval, 0.56 to 0.72]; adjusted hazard ratio for ESRD per 1 SD higher level of UCr, 0.70 [95% confidence interval, 0.63 to 0.75]).

Conclusions

Among a cohort of individuals with CKD, lower UCr is associated with death and ESRD independent of FFM as assessed by bioelectrical impedance analysis.     

Serum levels of homocysteine in mice with malignant tumours

BACKGROUND:

Oxygen radicals and malondialdehyde (MDA) are tumourigenic. Homocysteine generates oxygen radicals. The possibility exists that hyperhomocysteinemia is a risk factor for cancer.

OBJECTIVE:

To investigate if serum levels of homocysteine and MDA are elevated in mice with malignant tumours.

METHODS:

Levels of serum homocysteine and MDA were estimated in 22 control and 22 tumour-bearing Balb/c mice.

RESULTS:

Serum homocysteine levels in control and tumour-bearing mice were 3.01±0.26 μmol/L and 4.05±0.46 μmol/L, respectively. The serum levels of MDA were 6.23±0.72 nmol/mL and 11.60±1.72 nmol/mL, respectively, in control and tumour-bearing mice.

CONCLUSION:

These results suggest that cancer in mice is associated with an increase in serum levels of homocysteine and the lipid peroxidation product MDA. It is, however, not known if this rise in homocysteine and MDA is due to cancer or if this rise causes cancer.     

Effect of diabetes mellitus on outcomes of hyperglycemia in a mixed medical surgical intensive care unit

Background:

Intensive insulin therapy and degree of glycemic control in critically ill patients remains controversial, particularly in patients with diabetes mellitus. We hypothesized that diabetic patients who achieved tight glucose control with continuous insulin therapy would have less morbidity and lower mortality than diabetic patients with uncontrolled blood glucose.

Method:

A retrospective chart review was performed on 395 intensive care unit (ICU) patients that included 235 diabetic patients. All patients received an intravenous insulin protocol targeted to a blood glucose (BG) level of 80–140mg/dl. Outcomes were compared between (a) nondiabetic and diabetic patients, (b) diabetic patients with controlled BG levels (80–140mg/dl) versus uncontrolled levels (>140 mg/dl), and (c) diabetic survivors and nonsurvivors.

Results:

Diabetic patients had a shorter ICU stay compared to nondiabetic patients (10 ± 0.7 vs 13 ± 1.1, p = .01). The mean BG of the diabetic patients was 25% higher on average in the uncontrolled group than in the controlled (166 ± 26 vs 130 ± 9.4 mg/dl, p < .01). There was no difference in ICU and hospital length of stay (LOS) between diabetic patients who were well controlled compared to those who were uncontrolled. Diabetic nonsurvivors had a significantly higher incidence of hypoglycemia (BG <60 mg/dl) compared to diabetic survivors.

Conclusion:

The results showed that a diagnosis of diabetes was not an independent predictor of mortality, and that diabetic patients who were uncontrolled did not have worse outcomes. Diabetic nonsurvivors were associated with a greater amount of hypoglycemic episodes, suggesting these patients may benefit from a more lenient blood glucose protocol.     

Evaluation of MicroRNAs miR-196a,miR-30a-5P,and miR-490 as Biomarkers of Disease Activity among Patients with FSGS

Background and objectives

This study aimed to identify urinary microRNAs (miRNAs) as biomarkers for FSGS disease activity.

Design, setting, participants, & measurements

Candidate urinary miRNAs were identified in pooled urine samples from patients with active FSGS (FSGS-A) and FSGS in remission (FSGS-CR), and were then validated using individual samples. Their levels were compared both under different treatment responses in a prospective study of FSGS and in patients with different membranous nephropathy (MN) and diabetic nephropathy (DN) disease activity. The prediction of these miRNAs for treatment responses was further analyzed in both retrospective and prospective cohorts of patients with FSGS.

Results

All 54 miRNAs were included as candidate biomarkers, including those with high levels in patients with FSGS-A (n=9) under the TaqMan Low Density Array as well as those with conserved expression in kidneys and involved in immune response. TaqMan probe-based quantitative RT-PCR confirmed the higher levels of four miRNAs in patients with FSGS-A in two independent cohorts (n=18 and n=80). Urinary miR-196a, miR-30a-5p, and miR-490 discriminated FSGS-A from FSGS-CR, with an area under the curve of ≥0.80. After steroid treatment, their levels were lower in steroid-responsive patients with FSGS (all P<0.001), but were unchanged in steroid-resistant patients. The levels of miRNAs were similar between active MN and MN in remission as well as active DN and incipient DN (all P>0.05). Urinary miR-30a-5p marginally predicted the response to steroid treatment in patients with FSGS-A, with an area under the curve of 0.63 (P=0.03).

Conclusions

The levels of urinary miR-196a, miR-30a-5p, and miR-490 are associated with FSGS disease activity.     

Low albumin levels and high impedance ratio as risk factors for worsening kidney function during hospitalization of decompensated heart failure patients

BACKGROUND:

Patients hospitalized for decompensated heart failure (DHF) frequently experience worsening of renal function (WRF), leading to volume overload and resistance to diuretics.

OBJECTIVE:

To investigate whether albumin levels and whole-body impedance ratio, as an indicator of water distribution, were associated with WRF in patients with DHF.Methods: A total of 80 patients hospitalized for DHF were consecutively included in the present longitudinal study. WRF during hospitalization was defined as an increase of ≥0.3 mg/dL (≥26.52 μmol/L) or 25% of baseline serum creatinine. Clinical and echocardiographic characteristics were assessed at baseline. Whole-body bioelectrical impedance was measured using tetrapolar and multiple-frequency equipment to obtain the ratio of impedance at 200 kHz to that at 5 kHz. Serum albumin levels were also evaluated. Baseline characteristics were compared between patients with and without deteriorating renal function using a t test or χ² test. Subsequently, a logistic regression analysis was performed to obtain the independent variables associated with WRF.

RESULTS:

The incidence of WRF during hospitalization was 26%. Independent risk factors associated with WRF were low serum albumin (RR=0.11; P=0.04); impedance ratio >0.85 (RR=5.3; P=0.05), systolic blood pressure >160 mmHg (RR=12; P=0.02) and maximum dose of continuous intravenous furosemide required >80 mg/day during hospitalization (RR=5.7, P=0.015).

CONCLUSIONS:

WRF is frequent in patients with DHF. It results from the inability to effectively regulate volume status because hypoalbuminemia induces water loss from the vascular space (high impedance ratio), and high diuretic doses lower circulatory volumes and reduce renal blood flow, leading to a decline in renal filtration function.     

Irisin in response to acute and chronic whole-body vibration exercise in humans

Objective

Irisin is a recently identified myokine, suggested to mediate the beneficial effects of exercise by inducing browning of white adipocytes and thus increasing energy expenditure. In humans, the regulation of irisin by exercise is not completely understood. We investigated the effect of acute and chronic whole-body vibration exercise, a moderate-intensity exercise that resembles shivering, on circulating irisin levels in young healthy subjects.

Materials/Methods

Healthy untrained females participated in a 6-week program of whole-body vibration exercise training. Blood was drawn before and immediately after an acute bout of exercise at baseline (week 0) and after 6 weeks of training.

Results

The resting irisin levels were not different at baseline (week 0) and after 6 weeks of training. At both 0 and 6 weeks of training, an acute bout of vibration exercise significantly elevated circulating irisin levels by 9.5% and 18.1%, respectively (p = 0.05 for the percent change of irisin levels).

Conclusions

Acute bouts of whole-body vibration exercise are effective in increasing circulating irisin levels but chronic training does not change levels of baseline irisin levels in humans.     

Cardiorespiratory Fitness Is Independently Associated with 25-Hydroxyvitamin D in Chronic Kidney Disease

Summary

Background and objectives

Vitamin D is an established important contributor to muscle function and aerobic metabolism. Hypovitaminosis D is highly prevalent in CKD patients and is associated with increased cardiovascular (CV) mortality via unknown mechanisms. Because aerobic-exercise capacity strongly predicts future CV events, we hypothesized that vitamin D status could be linked to CV outcomes via an effect on maximum aerobic-exercise capacity in patients with CKD and that this effect may be mediated in part via its actions on muscle strength and functional ability.

Design, setting, participants, & measurements

Baseline demographic, anthropometric, and biochemical data were collected in a cross-sectional study of patients with moderate CKD. Peak aerobic capacity was determined during treadmill stress testing using metabolic equivalence of tasks. Physical activity was assessed using the Active Australia questionnaire, grip strength by dynamometer, and functional capacity by “Up & Go” testing.

Results

The study included 85 participants (age 59.5 ± 9.7 years, 60% male, 44% diabetic, 92% Caucasian; mean serum 25-hydroxyvitamin D [25-OHD] 78.4 ± 29.4 nmol/L). We demonstrated that 25-OHD status was independently associated with aerobic-exercise capacity (β = 0.2; P = 0.008). Aerobic-exercise capacity was also predicted by younger age, white race, smaller waist circumference, absence of a previous angina history, and increasing weekly physical activity. However, neither muscle strength nor functional ability were significantly associated with 25-OHD.

Conclusions

Vitamin D is independently associated with aerobic capacity in CKD patients, and this finding is not explained by changes in muscle strength or functional ability.     

Serum Irisin Levels,Precocious Myocardial Infarction,and Healthy Exceptional Longevity

Background

Skeletal muscles produce irisin. Growing controversy exists on the association between this myokine and chronic disease risk. On the basis of the potential protective effects that irisin could exert on both vascular function and skeletal muscle mass, we hypothesized that an elevated level of this molecule may contribute to successful aging.

Methods

Serum irisin levels were measured using enzyme-linked immunosorbent assay in disease-free centenarians, young healthy controls, and patients with precocious acute myocardial infarction.

Results

We found the highest levels of serum irisin in disease-free centenarians (35.3 ± 5.5 ng/mL) compared with young healthy controls (20.7 ± 6.3 ng/mL) and especially with young patients with acute myocardial infarction (15.1 ± 5.4 ng/mL).

Conclusions

Our study demonstrates that healthy centenarians are characterized by increased serum irisin levels, whereas levels of this molecule were found to be significantly lower in young patients with myocardial infarction. Our findings may prompt further research into the role played by irisin not only in vascular disorders but also in life span modulation.     

Complication Reducing Effect of the Information Technology-Based Diabetes Management System on Subjects with Type 2 Diabetes

Objective

We introduced a new information technology-based diabetes management system, called the Internet-based glucose monitoring system (IBGMS), and demonstrated its short-term and long-term favorable effects. However, there has been no report on clinical effects of such a new diabetes management system on the development of diabetic complications so far. This study was used to simulate the complication reducing effect of the IBGMS, given in addition to existing treatments in patients with type 2 diabetes.

Research Design and Methods

The CORE Diabetes Model, a peer-reviewed, published, validated computer simulation model, was used to project long-term clinical outcomes in type 2 diabetes patients receiving the IBGMS in addition to their existing treatment. The model combined standard Markov submodels to simulate the incidence and progression of diabetes-related complications.

Results

The addition of IBGMS was associated with improvements in reducing diabetic complications, mainly microangiopathic complications, including diabetic retinopathy, diabetic neuropathy, diabetic nephropathy, and diabetic foot ulcer. The IBGMS also delayed the development of all diabetic complications for more than 1 year.

Conclusions

This study demonstrated that the simulated IBGMS, compared to existing treatment, was associated with a reduction of diabetic complications. As a result, it provides valuable evidence for practical application to the public in the world.     

Factors associated with length of stay in hospital for suspected community-acquired pneumonia

OBJECTIVE:

To determine factors associated with the length of stay (LOS) for patients with suspected community-acquired pneumonia (CAP) who required hospitalization for treatment.

STUDY DESIGN:

The authors studied a population-based prospective cohort of 2757 adults with suspected CAP who were admitted over a two-year period. Logistic regression, multiple linear regression, and classification and regression trees were used to determine the factors associated with LOS.

SETTING:

The study was conducted in two community and tertiary care hospitals, two community and secondary care hospitals, and two community hospitals in the Capital Health Region of Edmonton, Alberta.

RESULTS:

Symptoms such as sweats, shaking chills and wheezing were associated with an LOS of seven days or shorter, whereas weight loss, functional impairment, heart, renal or neoplastic diseases and time to first dose of antibiotic were predictive of an LOS greater than seven days. Regression tree analysis indicated that rapid achievement of physiological stability was associated with a shorter LOS. The use of an indwelling urinary catheter was found to be an important determinant of LOS.

CONCLUSIONS:

The present study found several new associations with increased LOS in patients with CAP, including functional status, time to receipt of first dose of antibiotic therapy, use of certain antibiotics, presence of a urinary catheter and the importance of time to physiological stability. An intervention targeting avoidance of urinary catheters may be associated with a shorter LOS.     

Acute inflammatory and anabolic systemic responses to peak and constant-work-rate exercise bout in hospitalized patients with COPD

Study objectives:

To explore the acute systemic inflammatory and anabolic effects of cycling in hospital admitted patients with chronic obstructive pulmonary disease (COPD) and in patients with clinically stable disease.

Design:

Cross-sectional comparative study.

Setting:

University Hospital Gasthuisberg, a tertiary care setting.

Patients:

16 patients with clinically stable COPD (no acute exacerbation in the past 12 weeks; median age: 73 years (IQR: 60 to 75); median forced expiratory volume in the first second (FEV₁): 45% predicted (IQR: 33 to 58)) and 14 patients who were admitted to a hospital due an acute exacerbation of COPD (median age: 65 years (IQR: 59 to 74); median FEV₁ to on day 8 of hospital stay: 41% predicted (IQR: 33 to 54)).

Interventions:

None.

Measurements and results:

Circulating levels of C reactive protein, interleukin 6, interleukin 8 and insulin-like growth factor I were determined before, at the end and 2 and 30 minutes after a symptom-limited peak cycling test and before, at the end and 2 and 30 minutes after a symptom-limited constant-work-rate cycling test at 70% of the peak load. Non-significant changes in the circulating markers of inflammation and anabolism were found during or up to 30 minutes after ceasing the peak or constant-work-rate cycling exercise tests. The systemic responses of the hospitalized patients with COPD did not differ from those with clinically stable disease.

Conclusions:

High-intensity cycling exercises did not increase the circulating levels of inflammatory markers in patients with chronic obstructive pulmonary disease, irrespective of their clinical stability.