desmosine and Cystic-Fibrosis

Cystic fibrosis (CF) lung disease is characterized by structural changes and remodeling in airway architecture and lung parenchyma. Neutrophilic inflammation and infection lead to injury and breakdown of airway matrix constituents, including elastin. The non-invasive measurement of urinary desmosine (UDes), a breakdown product of elastin, may be reflective of ongoing lung injury and may serve as a biomarker of active short-term damage during pulmonary exacerbation. Our objectives were to measure desmosine in the urine of CF patients hospitalized for treatment of a pulmonary exacerbation and to explore the correlation between desmosine concentration and other markers of clinical improvement, including lung function and inflammatory mediators.. Urine and blood samples plus lung function measurements were collected at up to three points during hospitalization for treatment of a CF pulmonary exacerbation. We used a repeated measures model, adjusted for age and time between measurements, to compare log transformed urine desmosine concentrations across multiple time points and to correlate those concentrations with related clinical variables. Change in UDes concentration was investigated using a statistical model that incorporated normalization factors to account for variations in urinary concentration.. Desmosine was measured by radioimmunoassay (RIA) in 155 spot urine samples from 53 CF patients hospitalized for 63 pulmonary exacerbations (range of results: 0-235 pmol Des/ml). Specific gravity (SG) adjusted UDes concentration decreased significantly during admission for CF pulmonary exacerbation, P < 0.01 (average length of stay = 11 days). No correlation was observed between UDes concentration and lung function or inflammatory markers.. UDes decreased significantly following treatment for an acute pulmonary exacerbation and may be a useful biomarker of short-term injury to the CF lung. Further investigation is needed to evaluate the utility of UDes concentration in the long-term progression of CF lung disease.

Topics: Airway Remodeling; Biomarkers; C-Reactive Protein; Cohort Studies; Cystic Fibrosis; Desmosine; Disease Progression; Elastin; Female; Humans; Interleukin-8; Lung Injury; Male; Pneumonia; Prospective Studies; Respiratory Function Tests

In infected lungs of the cystic fibrosis (CF) patients, opportunistic pathogens and mutated cystic fibrosis transmembrane conductance regulator protein (CFTR) contribute to chronic airway inflammation that is characterized by neutrophil/macrophage infiltration, cytokine release and ceramide accumulation. We sought to investigate CF lung inflammation in the alveoli.. Lung tissue from 14 CF patients and four healthy individuals was analyzed for numbers of effector cells, elastin and collagen concentrations, inflammatory markers and density of Pseudomonas aeruginosa. Additionally, desmosine and isodesmosine concentrations were determined in 52 urine specimens from CF patients to estimate the burden of elastase activities in respiratory secretions.. Elastin concentration was significantly decreased and collagen significantly increased in CF alveolar tissues as compared to age-matched, healthy individuals. Elastin split products were significantly increased in urine samples from patients with CF and correlated inversely with age, indicating local tissue remodelling due to elastin degradation by unopposed proteolytic enzymes. Alveolar inflammation was also characterized by a significant cell infiltration of neutrophils, macrophages and T cells, extensive nuclear factor-kappaB and insulin-like growth factor-1 activation in various cell types and increased intercellular adhesion molecule-1 expression, and increased numbers of myofibroblasts. Additionally, ceramide accumulated in type II alveolar epithelial cells, lacking CFTR. P. aeruginosa organisms were rarely present in inflamed alveoli.. Chronic inflammation and remodeling is present in alveolar tissues of the CF lung and needs to be addressed by anti-inflammatory therapies.

Topics: Adolescent; Adult; Case-Control Studies; Ceramides; Collagen; Cystic Fibrosis; Desmosine; Elastin; Female; Humans; Inflammation; Isodesmosine; Male; Pseudomonas aeruginosa; Pulmonary Alveoli; Young Adult

Cystic fibrosis (CF) lung disease is characterized by structural changes in the airways and parenchyma. No sputum biomarker exists to measure the degree of active structural destruction during pulmonary exacerbation in patients with CF. The noninvasive measurement of desmosine, a breakdown product of elastin, may reflect ongoing lung injury and serve as a biomarker of short-term damage. Our objectives were to measure desmosine in the sputum of patients with CF hospitalized for treatment of a pulmonary exacerbation and to explore the correlation between desmosine levels and other markers of clinical improvement, including lung function and inflammatory mediators, following hospitalization.. Sputum and blood samples collected and lung function measurements were made at multiple time points during hospitalization. We used a repeated measures model, adjusted for age and time between measurements, to compare log-transformed sputum desmosine levels across multiple time points and to correlate those levels with related variables.. Desmosine levels were measured by radioimmunoassay in 71 expectorated sputum samples from 19 patients with CF hospitalized for 26 pulmonary exacerbations (range of results, 0 to 200 pmol/L desmosine/mL). Sputum desmosine levels decreased significantly during the first week of hospitalization (p = 0.04). Desmosine levels were positively associated with plasma C-reactive protein (rho = 0.59; p = 0.03), sputum interleukin-8 (rho = 0.86; p < 0.01), and sputum neutrophil elastase (rho = 0.78; p < 0.01).. Sputum desmosine, a novel measure of acute structural lung injury, may serve as a marker of structural lung damage occurring during exacerbations of lung disease in CF.

Topics: Adolescent; Adult; Biomarkers; C-Reactive Protein; Child; Cohort Studies; Cystic Fibrosis; Desmosine; Female; Hospitalization; Humans; Interleukin-8; Leukocyte Elastase; Lung; Male; Prospective Studies; Severity of Illness Index; Sputum; Young Adult

Degradation of extracellular matrix components is central to many pathological features of chronic destructive lung disorders. Desmosine and isodesmosine are elastin-derived cross-linked amino acids whose urine levels are considered representative of elastin breakdown. The aim of this study was to apply a novel methodology, based on high-performance capillary electrophoresis, to the quantification of desmosine and isodesmosine in 11 patients with stable chronic obstructive pulmonary disease (COPD), 10 with an exacerbation of COPD, nine with alpha1-antitrypsin deficiency, 13 with bronchiectasis, and 11 adults with cystic fibrosis, in comparison to 24 controls. It was found that, in patients with stable COPD, urinary desmosine levels were higher than in controls (p=0.03), but lower than in COPD subjects with an exacerbation (p< or =0.05). The highest desmosine levels were found in subjects with alpha1-antitrypsin deficiency, bronchiectasis and cystic fibrosis (p<0.001 versus stable COPD). In a short-term longitudinal study, five stable COPD patients showed a constant rate of desmosine excretion (mean coefficient of variation <8% over three consecutive days). In conclusion, the present method is simple and suitable for the determination of elastin-derived cross-linked amino acid excretion in urine, giving results similar to those obtained using other separation methods. In addition, evidence is presented that urinary desmosine excretion is increased in conditions characterized by airway inflammation, such as exacerbations of chronic obstructive pulmonary disease, bronchiectasis and cystic fibrosis. Results obtained in subjects with alphal-antitrypsin deficiency suggest that this method might be used to evaluate the putative efficacy of replacement therapy.

Topics: Adult; Aged; Aged, 80 and over; alpha 1-Antitrypsin Deficiency; Bronchiectasis; Cross-Linking Reagents; Cross-Sectional Studies; Cystic Fibrosis; Desmosine; Elastin; Electrophoresis, Capillary; Emphysema; Extracellular Matrix; Female; Humans; Isodesmosine; Longitudinal Studies; Lung Diseases, Obstructive; Male; Middle Aged

Neutrophil elastase is involved in the pathogenesis of several pulmonary diseases; a strategy for monitoring in vivo elastase activity is to measure changes in biochemical markers. The objective of this study was to determine whether differences in the urinary excretion of the elastin crosslinks, desmosine and isodesmosine (which are unique amino acid products of elastase activity), could be discerned between groups of patients with chronic obstructive pulmonary disease (COPD) or cystic fibrosis (CF), and non-diseased, age-matched controls. Twenty-four-hour urine collections were analysed to eliminate variations in excretion throughout the day, and urine was collected on four separate days in 29-31 subjects/group to investigate the variability in desmosines excretion among the groups. Both sets of patient populations had significantly more variable desmosines readings (higher standard deviations) relative to their respective age-matched control group. The means for three adult groups (COPD, controls and a COPD-smoker subset) ranged from 28.4 to 35.5 pmol desmosines/mg creatinine and there were no differences among the groups. Values in children were higher: 55 pmol desmosines/mg creatinine in the non-CF children and 77 pmol desmosines/mg creatinine for the CF group (P<0.01 vs. age-matched controls). The results of this study show that urinary desmosines, as a surrogate marker for enhanced elastase activity, are more highly variant in both patient populations relative to age-matched controls, and an overall increase in the mean value is further observed in patients with cystic fibrosis.

Topics: Biomarkers; Case-Control Studies; Child; Cystic Fibrosis; Desmosine; Female; Humans; Isodesmosine; Leukocyte Elastase; Lung Diseases, Obstructive; Male; Middle Aged

Elastin degradation has been reported to be increased in patients with cystic fibrosis (CF). In order to further explore evidence for elastin degradation in a group of 18 patients with CF with a wide range of disease severity, we used an isotope dilution method to measure urinary desmosine (DES) and isodesmosine (IDES), amino acids derived exclusively from cross-linked elastin, and hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP), amino acids derived exclusively from cross-linked collagen. Urinary DES and IDES (mean +/- SD) were 23.9 +/- 30.7 and 18.5 +/- 22.4 micrograms/g creatinine, respectively, in the patients with CF versus 7.5 +/- 1.7 and 6.8 +/- 1.4 micrograms/g creatinine, respectively, in 10 healthy control subjects (p < 0.001); only two patients with CF had DES values within the control range. The values of urinary HP and LP in the CF group were 54.9 +/- 39.1 and 12.3 +/- 8.6 nmol/mmol creatinine, respectively, versus 24.5 +/- 5.8 and 5.1 +/- 2.7 nmol/mmol creatinine, respectively, in the controls (p < 0.005). Both HP and LP were highly correlated (r = 0.71, p < 0.0001). Patients with CF had active pulmonary inflammation; neutrophils were abundant in the bronchoalveolar lavage fluid of the CF group and correlated with elastase activity measured with methoxysuccinyl Ala-Ala-Pro-Val paranitroanilide (r = 0.61, p < 0.05). Airway neutrophils had decreased expression of the complement receptor CR1 (CR1/CR3 of 0.17 +/- 0.15 versus 1.0 for blood neutrophils), a change known to be caused by uninhibited neutrophil elastase. We conclude that lung elastin is the most likely source of the increased DES and IDES in CF.

Topics: Adult; Amino Acids; Bronchoalveolar Lavage Fluid; Case-Control Studies; Collagen; Cystic Fibrosis; Desmosine; Elastin; Female; Humans; Isodesmosine; Leukocyte Elastase; Male; Neutrophils; Pancreatic Elastase; Receptors, Complement

A modified radioimmunoassay (RIA) for desmosine in the urine was investigated as a tool for the rapid estimation of lung elastin catabolism. Cystic fibrosis (CF) and oxygen toxicity were chosen as conditions that might show altered elastin destruction. Using an antibody bound to magnetic particles the RIA was adapted to handle large numbers of samples requiring only 50 microliters or urine. The experiments show that it was not necessary to hydrolyze or extract the urine prior to assay and that collecting spot urines and normalizing the data to urine creatinine gives the same interpretation of the data as total desmosine in a 24-hour collection. Urine desmosine levels were elevated in 10 of 16 patients with CF; however, daily fluctuations were considerable in some subjects, varying as much as 5-fold and underlining the importance of assaying several consecutive days of urine in acute disorders for an accurate estimate of desmosine excretion. The RIA for desmosine is a rapid and sensitive assay that requires no sample preparation and could be applied to clinical situations that require large numbers of samples.

Topics: Acute Disease; Adolescent; Adult; Child; Child, Preschool; Cystic Fibrosis; Desmosine; Humans; Hyperoxia; Male; Radioimmunoassay; Sensitivity and Specificity

The risk for proteolysis of lung connective tissue was evaluated in patients with cystic fibrosis (CF) with chronic, severe lung infections by measuring uninhibited elastase activity in sputum samples and urinary excretion of desmosines (cross-linking amino acids in elastin). Of the 16 patients included in the study, 11 were infected with Pseudomonas aeruginosa, 2 with Pseudomonas cepacia, and 2 with both P. aeruginosa and P. cepacia. Uninhibited elastase activity (0.34 to 20.2 micrograms elastin degraded/mg protein/30 min) was detected in the sputum samples from each of 13 patients tested. Serine elastase activity was detected in the sputum of each of 12 patients, and metalloelastase (P. aeruginosa elastase and possibly macrophage elastase) activity was detected in the sputum of 11 of 12 patients tested. Male patients with CF excreted significantly more elastin cross-links (desmosines) in their urine than did control male subjects (3.6 +/- 1.7 micrograms/kg/24 h versus 1.5 +/- 0.6 micrograms/kg/24 h; p less than 0.01), and there was a significant correlation (p less than 0.05) between urine desmosine excretion and the severity of lung disease in the patients with CF as indicated by chest roentgenogram score. In 3 autopsied patients, abnormal elastin fibers were seen by light microscopy in all lung compartments. Fragmented and exfoliated elastin, evidence of active elastolysis, was noted in bronchial ulcers and abscesses. The results of this study suggest that proteolytic destruction of lung connective tissue is an ongoing process in the chronically infected CF lung and that this proteolysis contributes to the pathologic changes observed in airways and alveolar parenchyma.

Topics: Adolescent; Adult; Connective Tissue; Cystic Fibrosis; Desmosine; Female; Humans; Lung; Male; Pancreatic Elastase; Peptide Hydrolases; Regression Analysis; Sputum