Bicarbonate in cystic fibrosis

Abstract

Background: Cystic fibrosis (CF, mucoviscidosis) is caused by mutations in the gene encoding CF transmembrane conductance regulator (CFTR), which is a chloride and bicarbonate channel necessary for fluid secretion and extracellular alkalization. For a long time, research concentrated on abnormal Cl^- and Na⁺ transport, but neglected bicarbonate as a crucial factor in CF.

Methods: The present short review reports early findings as well as recent insights into the role of CFTR for bicarbonate transport and its defects in CF.

Results: The available data indicate impaired bicarbonate transport not only in pancreas, intestine, airways, and reproductive organs, but also in salivary glands, sweat duct and renal tubular epithelial cells. Defective bicarbonate transport is closely related to the impaired mucus properties and mucus blocking in secretory organs of CF patients, causing the life threatening lung disease.

Conclusions: Apart from the devastating lung disease, abrogated bicarbonate transport also leads to many other organ dysfunctions, which are outlined in the present review.

Keywords: Bicarbonate; CFTR; Cystic fibrosis; Cystic fibrosis transmembrane conductance regulator; Mucoviscidosis; Mucus.