Chondroitin sulfate in sputum from patients with cystic fibrosis and chronic bronchitis.

In order to ascertain whether or not the presence of glycosaminoglycans in sputa of patients suffering from chronic bronchial disorders was related to tracheobronchial infection, an electrophoretic procedure was set up. The different acidic macromolecular components of sputum, namely nucleic acids, glycosaminoglycans, and bronchial glycopeptides could be identified in proteolyzed sputum using agarose electrophoresis before and after the action of different enzymes: nucleases, chondroitinases, hyaluronidase and heparinase. This procedure was used to analyze 13 sputum samples from patients suffering from cystic fibrosis (CF) and 12 sputum samples from patients suffering from chronic bronchitis. Chondroitin sulfate was identified in 11 infected sputum samples from patients with CF and also in the noninfected sputum from a patient with chronic bronchitis. These data suggest a relationship between the presence of chondroitin sulfate proteoglycans in sputum and severe tracheobronchial infection in CF.

Evidence for the in vivo degradation of human respiratory mucins during Pseudomonas aeruginosa infection.

The comparison of distribution of glycopeptides of sputa from patients suffering from various chronic hypersecretions has already shown an increased acidity with a decreased proportion of neutral glycopeptides in the respiratory secretions of patients suffering from cystic fibrosis, as compared to those of patients with chronic bronchitis. In order to find out whether this decrease is specific to cystic fibrosis mucins or whether it is due to a degradation of mucus by Pseudomonas aeruginosa, which infects most of the sputa from patients with this disease, mucus glycopeptides from patients with different chronic bronchial disorders, infected by Pseudomonas or not, were prepared and fractionated by ion-exchange chromatography. The neutral fraction, which has never been studied in detail, was gel-filtered, and provided two fractions, one containing true mucin glycopeptides and the other containing a mixture of peptides and glycopeptides with a lower molecular mass. In the Pseudomonas-infected samples, the true mucin glycopeptide fraction was greatly diminished as compared to this same fraction in non-Pseudomonas-infected samples; this was not specific to cystic fibrosis secretions. In contrast, the glycopeptide fraction with a lower molecular mass was greatly increased in all the Pseudomonas-infected samples. Polyacrylamide gel electrophoresis of this second fraction showed unique glycopeptide bands between 40-50 kDa in the Pseudomonas-infected samples, regardless of the origin of the samples. These bands were revealed by an antibody directed against whole cystic fibrosis mucin. Infected chronic bronchitis sputa and cystic fibrosis samples without P. aeruginosa did not show these bands. These studies therefore suggest that there are P. aeruginosa-associated changes in mucins which may result from degradation of mucins.

The binding of anti-pseudomonal antibiotics to macromolecules from cystic fibrosis sputum.

Antibiotics are known to bind to whole cystic fibrosis sputum. However, the composition of sputum varies from one patient to another, making the interpretation of binding studies difficult. This problem has been examined by standardising the macromolecule concentration of sputum from four cystic fibrosis patients and adding tobramycin or ceftazidime directly to the sputum components. Binding to mucin-rich and DNA-rich fractions of sputum was also studied before and after DNase treatment of these fractions. These studies indicated that (i) the degree of tobramycin binding is dependent on the sputum macromolecule concentration, (ii) a significant proportion of tobramycin is bound even at concentrations of 100 mg/l of drug, (iii) tobramycin binds to both the mucin rich fraction and the DNA rich fraction of sputum and (iv) ceftazidime binding to sputum is negligible. Our data indicate that there is a need to standardise sputum in antibiotic binding studies and they provide another rationale for favouring the use of ceftazidime over aminoglycosides in infectious exacerbations of cystic fibrosis caused by Pseudomonas aeruginosa.

[Comparative study of bronchial mucins isolated from the sputum of patients suffering from cystic fibrosis or other chronic bronchial diseases (author's transl)]. / Etude comparative des mucines bronchiques purifiées à partir de l'expectoration de sujets atteints de mucoviscidose ou d'autres affections bronchiques chroniques

Most of the mucins isolated from the sputum of patients suffering from cystic fibrosis are acidic. Acidic mucins from a child suffering from cystic fibrosis were degraded by alkali treatment. Analysis of the degradation products demonstrated the wide heterogeneity of the carbohydrate chains linked to the mucin polypeptide moiety. However, this heterogeneity of carbohydrate chains is probably not restricted to mucins from patients with cystic fibrosis. Bronchial mucins were prepared either from the sputum of different patients belonging to blood group O or B and suffering from cystic fibrosis, chronic bronchitis and other chronic bronchial diseases, or from bronchial washings performed in macroscopically healthy area of the bronchial tree of subjects belonging to blood group O. The chemical composition of each mucin fraction was established and an average carbohydrate chain length was estimated. Acidic mucins isolated from the sputum of two children suffering from cystic fibrosis were more sulfated than sialylated and their average carbohydrate chain length was relatively large. These characters were not specific for cystic fibrosis since they were also found in acidic mucins of two children suffering from other bronchial diseases. Most of the acidic mucins isolated from the sputum of three adults suffering from chronic bronchitis were more sialylated than sulfated and had a relatively short average carbohydrate chain length. The sputum of these patients also contained a variable proportion of neural or weakly acidic mucins. The mucins isolated from bronchial washings performed in macroscopically healthy areas of the bronchial tree were acidic molecules whose acidic characteristics and average carbohydrate chain length were about the same as for acidic mucins from patients with chronic bronchitis.