A New Method to Improve the Clinical Evaluation of Cystic Fibrosis Patients by Mucus Viscoelastic Properties

Abstract

In cystic fibrosis (CF) patients airways mucus shows an increased viscoelasticity due to the concentration of high molecular weight components. Such mucus thickening eventually leads to bacterial overgrowth and prevents mucus clearance. The altered rheological behavior of mucus results in chronic lung infection and inflammation, which causes most of the cases of morbidity and mortality, although the cystic fibrosis complications affect other organs as well. Here, we present a quantitative study on the correlation between cystic fibrosis mucus viscoelasticity and patients clinical status. In particular, a new diagnostic parameter based on the correlation between CF sputum viscoelastic properties and the severity of the disease, expressed in terms of FEV1 and bacterial colonization, was developed. By using principal component analysis, we show that the types of colonization and FEV1 classes are significantly correlated to the elastic modulus, and that the latter can be used for CF severity classification with a high predictive efficiency (88%). The data presented here show that the elastic modulus of airways mucus, given the high predictive efficiency, could be used as a new clinical parameter in the prognostic evaluation of cystic fibrosis.

Tensiometric and Phase Domain Behavior of Lung Surfactant on Mucus-like Viscoelastic Hydrogels

“…Higher Carbopol content gels than those studied here may be utilized as models of diseased tracheobronchial mucus (i.e. cystic fibrosis 4 or COPD).…”

Use of low field nuclear magnetic resonance to monitor lung inflammation and the amount of pathological components in the sputum of cystic fibrosis patients

“…Similar considerations can be done for T 2m and the variation of the systemic and local and inflammation markers (Figures A,B, A,B, and A,B). Second, the sample volume used is in line with the amounts considered suitable in recent studies of the rheological properties of CF sputum in relation to FEV 1 . Finally, the sputum volume chosen is dictated by the fact that higher amounts cannot be realistically obtained from patients.…”

Rheological properties of synthetic mucus for airway clearance

“…It is also the case of Boegh et al who tried to propose a bio‐similar mucus composition displaying rheological properties (notably in terms of shear‐thinning) close to the composition of a mucus isolated from cultured cells. Finally, Tomaiuolo et al also described the shear‐thinning nature of different native CF mucus samples without proposing any quantification of this property. More generally, the increase in shear‐thinning behavior with the polymer concentration, is classical for aqueous polymer solutions.…”

“…In these cases, the measured properties mostly reflect the flow behavior of mucus and can be used to investigate its viscosity under physiological shearing rates prevailing in human lungs during normal functioning or during temporary events such as cough. Even in studies where both dynamic oscillatory and shear flow measurements were carried out, the thixotropic nature of mucus was not accounted for, or at least not quantitatively . As a consequence, a complete and intrinsically consistent characterization campaign is still missing in the open literature.…”