Autoantibodies of IgM and IgG classes show differences in recognition of multiple autoantigens in chronic obstructive pulmonary disease.

Autoimmunity occurs in chronic obstructive pulmonary disease (COPD). We describe an antigen microarray for detecting serum autoantibodies (AAbs) to determine how IgM, as well as IgG, AAbs distinguish patients with COPD from controls with a history of smoking without COPD. All COPD patients' sera contained elevated levels of AAbs to some of 30 autoantigens. There were significant differences in the autoantigenic specificities of IgM AAbs compared to IgG AAbs in the COPD sera: for example, AAbs to histone and scl-70 were mainly IgG, whereas AAbs to CENP-B and La/ssB were mainly IgM; by contrast, IgM and IgG AAbs to collagen-V were equally prevalent. Thus, a combination of IgM and IgG AAbs specific for multiple autoantigens are detected in all cases of COPD at a level at which all non-COPD controls are negative for AAbs. This highlights the importance of different classes of AAbs to a range of autoantigens in COPD.

Evaluating the role of inflammation in chronic airways disease: the ERICA study.

Extrapulmonary manifestations are recognized to be of increasing clinical importance in Chronic Obstructive Pulmonary disease. To investigate cardiovascular and skeletal muscle manifestations of COPD, we developed a unique UK consortium funded by the Technology Strategy Board and Medical Research Council comprising industry in partnership with 5 academic centres. ERICA (Evaluating the Role of Inflammation in Chronic Airways disease) is a prospective, longitudinal, observational study investigating the prevalence and significance of cardiovascular and skeletal muscle manifestations of COPD in 800 subjects. Six monthly follow up will assess the predictive value of plasma fibrinogen, cardiovascular abnormalities and skeletal muscle weakness for death or hospitalization. As ERICA is a multicentre study, to ensure data quality we sought to minimise systematic observer error due to variations in investigator skill, or adherence to operating procedures, by staff training followed by assessment of inter- and intra-observer reliability of the four key measurements used in the study: pulse wave velocity (PWV), carotid intima media thickness (CIMT), quadriceps maximal voluntary contraction force (QMVC) and 6-minute walk distance (6MWT). This report describes the objectives and methods of the ERICA trial, as well as the inter- and intra-observer reliability of these measurements.

Dynamic vascular changes following intravenous antibiotics in patients with cystic fibrosis.

BACKGROUND: Adults with cystic fibrosis (CF) have altered large artery haemodynamics which is associated with a persisting systemic inflammatory state. We hypothesized that a short-term intervention favorably influencing the inflammatory status may modify their haemodynamic state. METHODS: Adult patients with CF were studied immediately preceding and following 2 weeks of intravenous antibiotics. Large artery haemodynamics, principally heart rate-adjusted augmentation index (AIx) were obtained. Blood pressure (BP), spirometry and CRP were also measured. RESULTS: Complete data was available for 15 patients; mean (SD) age 28 (6)years. CRP was reduced while FEV1% predicted improved. Following treatment AIx was lower: 10.9 (10.9)% to 8.1 (10.9)% (p<0.05) while BP was similar and a trend toward lower heart rate (p=0.06). Change in AIx was related to baseline FEV1% predicted (r=0.77) and BMI (r=0.71) (both P<0.01). CONCLUSION: The abnormal central haemodynamics evident in adults with CF is modulated with a short intervention of intravenous antibiotics.

Systemic comorbidities in bronchiectasis.

Bronchiectasis is a chronic inflammatory lung disease, which has similarities to chronic obstructive pulmonary disease (COPD). Comorbidities of COPD include increased risk of cardiovascular (CV) disease, loss of bone mineral density (BMD) and loss of skeletal muscle mass and function, all linked to systemic inflammation. The potential for such comorbidities has not been explored in bronchiectasis. We hypothesised that patients with bronchiectasis would have similar increased comorbidities. A total of 20 patients with noncystic fibrosis bronchiectasis were compared to 20 controls similar in age, gender and smoking exposure. Assessments included aortic pulse wave velocity (PWV; (a measure of arterial stiffness and an independent predictor of CV risk), blood pressure (BP) as well as levels of interleukin-6 (IL-6), albumin, fasting glucose and lipids. Body composition (fat free mass index (FFMI)), BMD, the 6-min walk distance (6MWD) and self-reported physical activity were also determined. Patients with bronchiectasis had increased aortic PWV, 10.5 (3.0) m/second, when compared with controls, 8.8 (1.6) m/second (p < 0.05), despite similar central and peripheral BP and lipid profile. Patients also had increased IL-6 and reduced albumin and glucose. Although mean body mass index, FFMI and BMD were similar in patients and controls, only 20% of patients had a healthy BMD compared with 50% of controls. Patients had reduced 6MWD and reported less physical activity (p < 0.05). Patients with bronchiectasis had increased arterial stiffness (an indicator of increased CV risk), increased inflammation, reduced exercise capacity and bone thinning. These additional comorbidities require further evaluation for their management in these patients.

Low bone mineral density in men with chronic obstructive pulmonary disease.

BACKGROUND: Osteoporosis is common in patients with COPD but the likely multi-factorial causes contributing to this condition (e.g. sex, age, smoking, therapy) mask the potential contribution from elements related to COPD. In order to study osteoporosis and bone mineral density (BMD) related to COPD, we studied a well-defined group of patients and controls. METHODS: BMD, forced expiratory volume in one second (FEV1), circulating bone biomarkers and biochemistry were determined in 30 clinically stable male ex-smokers with confirmed COPD and 15 age matched "ex-smoker" male controls. None of the patients were on inhaled corticosteroids or received more than one short course of steroids. RESULTS: Mean (SD) FEV1% predicted of patients was 64(6)%, the majority having Global Initiative for Chronic Obstructive Lung Disease (GOLD) II airflow obstruction. There were 5/30 patients and 1/15 controls who were osteoporotic, while a further 17 patients and 5 controls were osteopenic. The BMD at the hip was lower in patients than controls, but not at the lumbar spine. Mean values of procollagen type 1 amino-terminal propeptide and osteocalcin, both markers of bone formation, and Type 1 collagen ß C-telopeptide, a marker of bone resorption, were similar between patients and controls. However, all bone biomarkers were inversely related to hip BMD in patients (r = -0.51, r = -0.67, r = -0.57, p < 0.05) but did not relate to lumbar spine BMD. 25-OH Vitamin D was lower in patients. CONCLUSIONS: Men with COPD had a greater prevalence of osteoporosis and osteopenia than age matched male controls, with a marked difference in BMD at the hip. Bone biomarkers suggest increased bone turnover.

Does pulmonary rehabilitation address cardiovascular risk factors in patients with COPD?

BACKGROUND: Patients with COPD have an increased risk of cardiovascular disease. Whilst pulmonary rehabilitation has proven benefit for exercise tolerance and quality of life, any effect on cardiovascular risk has not been fully investigated. We hypothesised that pulmonary rehabilitation, through the exercise and nutritional intervention, would address these factors. METHODS: Thirty-two stable patients with COPD commenced rehabilitation, and were compared with 20 age and gender matched controls at baseline assessment. In all subjects, aortic pulse wave velocity (PWV) an independent non-invasive predictor of cardiovascular risk, blood pressure (BP), interleukin-6 (IL-6) and fasting glucose and lipids were determined. These measures, and the incremental shuttle walk test (ISWT) were repeated in the patients who completed pulmonary rehabilitation. RESULTS: On commencement of rehabilitation aortic PWV was increased in patients compared with controls (p<0.05), despite mean BP, age and gender being similar. The IL-6 was also increased (p<0.05). Twenty-two patients completed study assessments. In these subjects, rehabilitation reduced mean (SD) aortic PWV (9.8 (3.0) to 9.3 (2.7) m/s (p<0.05)), and systolic and diastolic BP by 10 mmHg and 5 mmHg respectively (p<0.01). Total cholesterol and ISWT also improved (p<0.05). On linear regression analysis, the reduction in aortic PWV was attributed to reducing the BP. CONCLUSION: Cardiovascular risk factors including blood pressure and thereby aortic stiffness were improved following a course of standard multidisciplinary pulmonary rehabilitation in patients with COPD.

The effect of exercise on large artery haemodynamics in cystic fibrosis.

BACKGROUND: Adult patients with cystic fibrosis (CF) have resting abnormal large artery haemodynamics. Here, we obtain further insight in patients with CF by evaluating haemodynamic response to physiological stress. METHODS: Thirty-six stable CF patients mean (SD) age 28.9 (9.0)years and 25 controls matched for age, gender and body mass index were studied. Central haemodynamic parameters; including augmentation index (AIx) and wasted left ventricular pressure energy (∆E(W)) were determined pre, during and post light intensity cycle ergometry. RESULTS: During exercise, despite a similar heart rate and blood pressure, patients had comparatively greater ∆E(W) (P=0.03) and trend towards greater AIx (P=0.07) than controls. Exercise ∆E(W) was greatest in patients with CF related diabetes (n=11). In all subjects, exercise ∆E(W) was related to age (r=0.54, P<0.001) and FEV(1)% predicted (r=-0.32, P=0.01). CONCLUSIONS: Adults with CF have an abnormal haemodynamic response to exercise. This finding has deleterious implications for myocardial performance.

Cardiovascular and musculskeletal co-morbidities in patients with alpha 1 antitrypsin deficiency.

BACKGROUND: Determining the presence and extent of co-morbidities is fundamental in assessing patients with chronic respiratory disease, where increased cardiovascular risk, presence of osteoporosis and low muscle mass have been recognised in several disease states. We hypothesised that the systemic consequences are evident in a further group of subjects with COPD due to Alpha-1 Antitrypsin Deficiency (A1ATD), yet are currently under-recognised. METHODS: We studied 19 patients with PiZZ A1ATD COPD and 20 age, sex and smoking matched controls, all subjects free from known cardiovascular disease. They underwent spirometry, haemodynamic measurements including aortic pulse wave velocity (aPWV), an independent predictor or cardiovascular risk, dual energy X-ray absorptiometry to determine body composition and bone mineral density. RESULTS: The aPWV was greater in patients: 9.9(2.1) m/s than controls: 8.5(1.6) m/s, p = 0.03, despite similar mean arterial pressure (MAP). The strongest predictors of aPWV were age, FEV1% predicted and MAP (all p < 0.01). Osteoporosis was present in 8/19 patients (2/20 controls) and was previously unsuspected in 7 patients. The fat free mass and bone mineral density were lower in patients than controls (p < 0.001). CONCLUSIONS: Patients with A1ATD related COPD have increased aortic stiffness suggesting increased risk of cardiovascular disease and evidence of occult musculoskeletal changes, all likely to contribute hugely to overall morbidity and mortality.

Excessive aortic inflammation in chronic obstructive pulmonary disease: an 18F-FDG PET pilot study.

UNLABELLED: Chronic obstructive pulmonary disease (COPD) patients exhibit increased cardiovascular risk, even after controlling for smoking. Inflammation may underlie this observation. METHODS: We measured vascular inflammation in both COPD patients and controls using (18)F-FDG PET/CT. Aortic inflammation was expressed as the target-to-background ratio (TBR) of the standardized uptake value in 7 COPD patients, 5 metabolic syndrome patients, and 7 ex-smokers. RESULTS: Abdominal aortic mean TBR (+/-SD) was greater in COPD patients than in ex-smoker controls (1.60 +/- 0.13 vs. 1.34 +/- 0.15, P = 0.0001). Aortic arch and abdominal aorta mean TBRs were higher in metabolic syndrome patients than in COPD patients (aortic arch, 1.80 +/- 0.18 vs. 1.53 +/- 0.18, P = 0.001, and abdominal aorta, 1.71 +/- 0.14 vs. 1.60 +/- 0.13, P = 0.001). CONCLUSION: COPD patients exhibited aortic inflammation that fell between the aortic inflammation exhibited by ex-smokers and that by metabolic syndrome patients. This may in part explain the increased risk of cardiovascular disease in COPD patients.

The effects of hypoxia on markers of coagulation and systemic inflammation in patients with COPD.

BACKGROUND: It has been demonstrated that there is an increased risk of venous thromboembolism (VTE) during air travel on flights of long duration. Patients with COPD are also at increased risk of VTE, particularly during exacerbations, possibly because of a hypercoagulable state secondary to hypoxia and/or heightened systemic inflammation. We investigated the effects of hypoxia on indices of coagulation and systemic inflammation in patients with COPD. METHODS: Twenty clinically stable patients with mild COPD were recruited. Patients were randomized to receive either medical air or 100% nitrogen through a 40% venturi mask at a flow rate of 10 L/min for 2 h. Blood was sampled for thrombin-antithrombin complex (TAT), prothrombin activation fragments 1 + 2 (F(1 + 2)), von Willebrand factor antigen (VWF:Ag), D-dimer, and interleukin-6 (IL-6) at baseline and after 2 h. RESULTS: Patients in the hypoxia and control groups were similar in terms of age, sex, pack-years smoked, and severity of airflow obstruction. There was no difference in baseline TAT, F(1 + 2), VWF:Ag, D-dimer, or IL-6 levels between groups. In the control group, there was no change in markers of coagulation or systemic inflammation over the 2-h study. In patients who underwent hypoxic challenge, there was an increase in TAT (P < .001), F(1 + 2) (P < .01), and IL-6 (P < .01), whereas D-dimer and VWF:Ag levels were unchanged. CONCLUSIONS: This study demonstrates that a 2-h hypoxic challenge in patients with COPD results in coagulation activation in conjunction with an increase in systemic inflammation.

Lung function in mid-life compared with later life is a stronger predictor of arterial stiffness in men: the Caerphilly Prospective Study.

BACKGROUND: Increased arterial stiffness predicts future cardiovascular disease and in some cross-sectional studies it is related to worse lung function and obstructive pulmonary disease. We assessed the predictive value of lung function measured in mid-life as compared with later life on arterial stiffness in the Caerphilly Prospective Study (CaPS). METHODS: Men aged 47-67 years had lung function measured between 1984 and 1988 and repeated between 2002 and 2004 (n = 827) as well as having carotid-femoral pulse wave velocity (PWV) measured. RESULTS: Both forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC) in mid-life and later life were inversely associated with PWV (P < 0.0001) but mid-life measures were stronger predictors. Only mid-life measures remained predictors after mutual adjustment (FEV(1) mid-life beta coeff. -0.65, 95% CI -1.04, -0.26, P < 0.0001; FVC mid-life beta coeff. -0.52, 95% CI -0.82, -0.23, P < 0.0001). Adjustment for smoking status, early life, inflammatory and metabolic factors in sub-groups did not markedly change the associations. CONCLUSIONS: Mid-life lung function is a stronger risk factor than in later life for arterial stiffness in men. It is possible that developmental factors influence both lung function and arterial stiffness. Lung function assessment in mid-life may identify individuals at greater risk of their future cardiovascular disease.

Predictors of poor attendance at an outpatient pulmonary rehabilitation programme.

BACKGROUND: Pulmonary rehabilitation (PR) is recommended for patients with respiratory disease who feel limited by breathlessness. Poor attendance wastes finite resources, increases waiting times and is probably associated with poorer clinical outcomes. We investigated what factors, identifiable from routine hospital data, predict poor attendance once enrolled in a pulmonary rehabilitation programme (PRP). METHODS: Retrospective case note study of 239 patients (60% male) of mean (S.D.) age of 66.6 (8.7) years, mean FEV(1) 39.6 (14.6)% predicted, who attended a 6 (short) or 18 (long) week, 18 session, outpatient PRP. Attendance data was analysed using linear multiple regression analysis with the log transformed odds ratio of attendance as the dependant variable. RESULTS: Overall median attendance was 16 out of 18 sessions. Being a current smoker (p<0.05), attending a long PRP (p<0.05), more previous hospital admissions (p<0.01), higher Medical Research Council (MRC) dyspnoea score (p<0.01) or enduring a long journey (p<0.001) were independent risk factors for low attendance. Lower body mass index (BMI) and distance from PR centre were of borderline importance (p<0.1) but age, gender, co-morbidity, respiratory diagnosis, FEV(1) and St. Georges Respiratory Questionnaire Score at baseline did not predict later attendance (p>0.2). CONCLUSIONS: Attendance at PRPs is independently influenced by smoking status, the degree of breathlessness, frequency of hospital admissions, length of the programme and journey time.

The influence of body composition on respiratory muscle, lung function and diaphragm thickness in adults with cystic fibrosis.

BACKGROUND: Weight loss and loss of fat-free mass (FFM) are associated with peripheral muscle wasting in cystic fibrosis (CF) although whether this co-exists with loss of diaphragm mass remains unclear. METHODS: FFM was determined by dual-energy X-ray absorptiometry and bioelectrical impedance in 40 adults with CF and 30 age-matched healthy subjects (HS). Diaphragm thickness at functional residual capacity (FRC) [TDIrel] and total lung capacity (TLC) [TDIcont] and thickening ratio (TR) were assessed by ultrasonography. Inspiratory muscle strength and work capacity were determined by maximal inspiratory pressure (PImax), and sustained PImax (SPImax); pulmonary function (RV, VC and TLC) and physical activity status (PAS) were also determined. RESULTS: When the CF patients were assessed as a group (low and normal FFM) they had similar age, weight, height and PAS compared to the HS, although patients had lower FFM (p<0.05), VC and TLC than the HS (p<0.01). In addition, although PImax, TDIrel, TDIcont and TR were similar between the patients and the HS, SPImax was lower in the patients (p<0.01). When analyses were made between patients with low versus normal FFM and between patients with low FFM and HS no significant differences were found between overall weight although TDIrel, TDIcont, TR and PAS were all reduced in patients with low FFM (p<0.01). CONCLUSIONS: PImax is relatively well preserved in adults with CF although there is a relationship between the loss of inspiratory muscle work capacity, FFM, PAS and pulmonary function. Furthermore loss of FFM is associated with loss of diaphragm muscle mass.

Cellular protein breakdown and systemic inflammation are unaffected by pulmonary rehabilitation in COPD.

BACKGROUND: Pulmonary rehabilitation can improve the functional capacity, but has a variable effect on the low fat-free mass (FFM) in patients with chronic obstructive pulmonary disease. HYPOTHESIS: Pulmonary rehabilitation would not affect catabolic drives such as systemic inflammation and also protein breakdown. METHODS: Patients (n = 40) were studied at the start of an 8-week in-patient pulmonary rehabilitation programme, at the end of the programme and 4 weeks later. FFM and functional capacity (quadriceps strength, handgrip strength and peak workload) were assessed. Pseudouridine (PSU) urinary excretion (cellular protein breakdown) and inflammatory status were determined. Healthy participants had a single baseline assessment (n = 18). RESULTS: PSU, (IL)-6 and soluble tumour necrosis factor (sTNF)alpha R75 were increased in patients compared with healthy participants, whereas FFM and functional capacity were reduced (all p < 0.01). PSU was inversely related to both FFM and skeletal muscle function. FFM and functional parameters increased with rehabilitation, but PSU and inflammatory status were unaffected. The gain in FFM was lost 4 weeks after the completion of rehabilitation (p < 0.01). CONCLUSION: The anabolic effect of pulmonary rehabilitation improved FFM, but it did not reverse the increased protein breakdown or systemic inflammation. Thus, on cessation of pulmonary rehabilitation the FFM gains were lost owing to a loss of anabolic drive.

The systemic inflammatory response to exercise in adults with cystic fibrosis.

Exercise is associated with release of inflammatory mediators in the circulation and there is evidence that the exercising muscles and tendons are sources of interleukin-6. Due to the catabolic effects of some cytokines, increased release in circulation might contribute to alterations in body composition in adults with cystic fibrosis. We hypothesised that exercise of moderate intensity would generate increased blood concentrations of some inflammatory mediators. We investigated the change in blood concentrations of interleukin-6, tumour necrosis factor alpha and their soluble receptors after a structured exercise (box stepping) of intensity similar to that encountered during activities of daily living in 12 adults with cystic fibrosis and mean (95% confidence interval) FEV1 55.6 (44.4, 66.8)% predicted, body mass index 23.0 (21.3, 24.6) kg/m2 and 12 healthy subjects. The increments post-exercise for all inflammatory mediators and lactate corrected for the work performed until voluntary exhaustion were greater for patients, while the total work was less for patients (all p<0.01). Daytime variability of the inflammatory mediators was assessed in eight patients and was less than the change due to exercise. We report greater increments in circulating concentrations of some cytokines with moderate exercise in adults with cystic fibrosis compared to healthy subjects.

Pulmonary cachexia, systemic inflammatory profile, and the interleukin 1beta -511 single nucleotide polymorphism.

BACKGROUND: Cachexia is common in chronic obstructive pulmonary disease (COPD) and is thought to be linked to an enhanced systemic inflammatory response. OBJECTIVE: We investigated differences in the systemic inflammatory profile and polymorphisms in related inflammatory genes in COPD patients. DESIGN: A cross-sectional study was performed in 99 patients with COPD (Global Initiative for Chronic Obstructive Lung Disease stages II-IV), who were stratified by cachexia based on fat-free mass index (FFMI; in kg/m2: <16 for men and <15 for women) and compared with healthy control subjects (HCs). Body composition was determined by bioelectrical impedance analysis. Plasma concentrations and gene polymorphisms of interleukin 1beta (IL-1beta -511), IL-6 (IL-6 -174), and the tumor necrosis factor system (TNF-alpha -308 and lymphotoxin-alpha +252) were determined. Plasma C-reactive protein, leptin, and urinary pseudouridine (as a marker of cellular protein breakdown) were measured. RESULTS: Fat mass, leptin, and pseudouridine were significantly different (P < 0.001) between noncachectic patients (NCPs) and cachectic patients (CPs: n = 35); the systemic inflammatory cytokine profile was not. NCPs had a body compositional shift toward a lower fat-free mass and a higher fat mass compared with HCs. CPs and NCPs had a greater systemic inflammatory response (P < 0.05) than did HCs, as reflected in C-reactive protein, soluble TNF-R75, and IL-6 concentrations. The overall distribution of the IL-1beta -511 polymorphism was significantly different between the groups (P < 0.05). CONCLUSIONS: In COPD patients, who are characterized by an elevated systemic inflammatory response, cachexia is not discriminatory for the extent of increase in inflammatory status. This study, however, indicates a potential influence of genetic predisposition on the cachexia process.

Inspiratory muscle training improves lung function and exercise capacity in adults with cystic fibrosis.

STUDY OBJECTIVES: To investigate the effects of high-intensity inspiratory muscle training (IMT) on inspiratory muscle function (IMF), diaphragm thickness, lung function, physical work capacity (PWC), and psychosocial status in patients with cystic fibrosis (CF). DESIGN: Twenty-nine adult patients with CF were randomly assigned to three groups. Two groups were required to complete an 8-week program of IMT in which the training intensity was set at either 80% of maximal effort (group 1; 9 patients) or 20% of maximal effort (group 2; 10 patients). A third group of patients did not participate in any form of training and acted as a control group (group 3; 10 patients). INTERVENTIONS: In all patients, baseline and postintervention measures of IMF were determined by maximal inspiratory pressure (Pimax), and sustained Pimax (SPimax); pulmonary function, body composition, and physical activity status were also determined. In addition, diaphragm thickness was measured at functional residual capacity (FRC) and total lung capacity (TLC) [TDIcont], and the diaphragm thickening ratio (TR) was calculated (TR = thickness during Pimax at FRC/mean thickness at FRC). Subjects also completed an incremental cycle ergometer test to exhaustion and two symptom-related questionnaires, prior to and following training. RESULTS: Following training, significant increases in Pimax and SPimax (p < 0.05), TDIcont (p < 0.05), TR (p < 0.05), vital capacity (p < 0.05), TLC (p < 0.05), and PWC (p < 0.05) were identified, and decreases in anxiety scores (p < 0.05) and depression scores (p < 0.01) were noted in group 1 patients compared to group 3 patients. Group 2 patients significantly improved Pimax and SPimax (both p < 0.05) only with respect to group 3 patients. No significant differences were observed in group 3 patients. CONCLUSION: An 8-week program of high-intensity IMT resulted in significant benefits for CF patients, which included increased IMF and thickness of the diaphragm (during contraction), improved lung volumes, increased PWC, and improved psychosocial status.

Cellular proteolysis and systemic inflammation during exacerbation in cystic fibrosis.

BACKGROUND: Weight loss indicates a poor prognosis in cystic fibrosis (CF). We hypothesised that fat-free mass (FFM) depletion and increased systemic inflammation would be associated with increased cellular proteolysis during an exacerbation of the respiratory symptoms. Patients were studied prospectively from the beginning of treatment with antibiotics when admitted to the Adults CF Centre. METHODS: Twenty six patients with CF were studied at the start and end of antibiotic treatment and 2 weeks later. Mean (95% CI) FEV1 when clinically stable was 54.1 (44.5, 62.6)% predicted. Urinary excretion of Pseudouridine (5-ribosyluracil, PSU) was determined as an indicator of cellular protein breakdown. Body composition was assessed by dual energy X-ray absorptiometry (DXA). RESULTS: Patients had increased concentrations of PSU at all assessments (p<0.01). Those with a low FFM had greater PSU (ratio to FFMI) than those with a normal FFM at all assessments. At the start of treatment, PSU was related to FFM, C-reactive protein (CRP) (p<0.05) and tumour necrosis factor (TNF)alpha soluble receptors (sr) I and II (p<0.01). Circulating inflammatory mediators were greater in patients than in healthy subjects at all assessments. CONCLUSION: Increased protein breakdown is associated with a low FFM and increased systemic inflammation and it may be a contributory mechanism of poor weight preservation in CF.

Hidden depletion of fat-free mass and bone mineral density in adults with cystic fibrosis.

BACKGROUND: Weight loss is associated with reduced survival in patients with cystic fibrosis (CF). OBJECTIVE: We hypothesized that some adult patients with a normal body mass index (BMI) have evidence of hidden fat-free mass (FFM) and bone mineral density (BMD) depletion that is linked to more severe disease. DESIGN: Fat mass (FM), FFM, and BMD were determined by dual-energy x-ray absorptiometry (DXA) and by bioelectric impedance in 56 adults in clinically stable condition and 20 age-matched healthy subjects. FM index and FFM index (FFMI) [kilograms per meter squared] of the right arm, leg, and trunk (ratio to height squared) were calculated. Lung function, including the maximum inspiratory pressure (MIP) and sustained MIP (SMIP), physical activity, serum C-reactive protein (CRP) and the number of exacerbations in the previous year were recorded. RESULTS: Patients had a lower total FFM than healthy subjects (p < 0.01), while FM was similar. Of the 56 patients, 30 patients had a normal BMI, of which 12 patients had a low FFM (hidden loss) by DXA. The right arm, leg, and trunk FFMI and BMD at hip sites were less in these patients than in those with a normal BMI and normal FFM (all p < 0.01). This group had a lower FEV(1), SMIP, more frequent exacerbations, and greater circulating CRP (all p < 0.05). CONCLUSIONS: In adults with CF, apparent or hidden loss of FFM, rather than weight loss, was related to overall disease severity. Hidden depletion of FFM was associated with increased loss of BMD and systemic inflammatory activity.

Pulmonary function, body composition, and protein catabolism in adults with cystic fibrosis.

Increased survival in cystic fibrosis (CF) is associated with bone thinning and fat-free mass (FFM) loss. We hypothesized that the severity of lung disease would be associated with increased protein catabolism and systemic inflammatory status in clinically stable patients. Forty adults with CF and 22 age-matched healthy subjects were studied. Body composition was determined by dual-energy X-ray absorptiometry. Urinary pseudouridine (PSU), a marker of protein breakdown, and cross-linked N-telopeptides of type I collagen (NTx), a marker of bone connective tissue breakdown, serum tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and their soluble receptors were measured. A 3-d food intake diary revealed 21 patients had a low energy intake. Excretion of PSU (p = 0.019) and NTx (p < 0.01) was increased in patients and was inversely related to FEV(1); PSU (r = - 0.53, p = 0.001) and NTx (r = - 0.43, p < 0.01). Increased excretion of PSU and NTx (p < 0.05 for both) was also related to a low FFM. All inflammatory mediators were greater in patients and were related to PSU and NTx. Clinically stable adults were catabolic with both cellular and connective tissue protein breakdown, which was related to lung disease severity, systemic inflammation, and body composition.