A physiological phase separation in airway mucus

Article type: Short Communication

Authors: Braun, F.N.

Affiliations: Institute of Medical Biology, University of Tromsø, Norway

Note: [] Address for correspondence: Dr. F.N. Braun, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway. Tel.: +47 77646832; E-mail: [email protected].

Abstract: The pathology of the disease cystic fibrosis is known to be associated very generally with ionic imbalance in the mucosal secretion which lines the respiratory tract, so-called airway surface liquid (ASL). The imbalance is caused by mutation of a transmembrane protein (CFTR) implicated in the control of ion traffic across the airway epithelium. It is feasible that CFTR malfunction undermines a putative phase-separated texture of healthy ASL which is apparent in electron microscopy images. A molecular statistical description of ASL is presented here with the aim of illustrating this hypothesis at the phenomenological level. The model predicts that a volume criterion and a salt criterion must be met in order to achieve the phase-separated texture. These predictions help to rationalise the findings of clinical trials. In conjunction with further experimental investigation, molecular statistical approaches in this spirit have the potential to play a useful role in the drive towards treatment strategies.

Keywords: Mucosal sol–gel transition, ion regulation, Donnan statistics, osmotic thermodynamics

DOI: 10.3233/BIR-2009-0524

Journal: Biorheology, vol. 46, no. 1, pp. 57-61, 2009