• Wayne H Anderson, Raymond D Coakley, Brian Button, Ashley G Henderson, Kirby L Zeman, Neil E Alexis, David B Peden, Eduardo R Lazarowski, C William Davis, Summer Bailey, Fred Fuller, Martha Almond, Bahjat Qaqish, Elena Bordonali, Michael Rubinstein, William D Bennett, Mehmet Kesimer, and Richard C Boucher.
• 1 Pulmonary and Critical Care Medicine, Department of Medicine.
• Am. J. Respir. Crit. Care Med. 2015 Jul 15; 192 (2): 182190182-90.

RationaleChronic bronchitis (CB) is characterized by persistent cough and sputum production. Studies were performed to test whether mucus hyperconcentration and increased partial osmotic pressure, in part caused by abnormal purine nucleotide regulation of ion transport, contribute to the pathogenesis of CB.ObjectivesWe tested the hypothesis that CB is characterized by mucus hyperconcentration, increased mucus partial osmotic pressures, and reduced mucus clearance.MethodsWe measured in subjects with CB as compared with normal and asymptomatic smoking control subjects indices of mucus concentration (hydration; i.e., percentage solids) and sputum adenine nucleotide/nucleoside concentrations. In addition, sputum partial osmotic pressures and mucus transport rates were measured in subjects with CB.Measurements And ResultsCB secretions were hyperconcentrated as indexed by an increase in percentage solids and total mucins, in part reflecting decreased extracellular nucleotide/nucleoside concentrations. CB mucus generated concentration-dependent increases in partial osmotic pressures into ranges predicted to reduce mucus transport. Mucociliary clearance (MCC) in subjects with CB was negatively correlated with mucus concentration (percentage solids). As a test of relationships between mucus concentration and disease, mucus concentrations and MCC were compared with FEV1, and both were significantly correlated.ConclusionsAbnormal regulation of airway surface hydration may slow MCC in CB and contribute to disease pathogenesis.

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