查看文章

James M. Wilson, Editor ductance, and by analogy with the sweat duct (11, 12) this allows salt levels in the ASL to remain at levels similar to those in plasma. The high salt in the ASL interferes with natural antibiotics such as defensins (13) and lysozyme. In marked contrast, the low volume hypothesis (14) is based on CFTR’s function as a regulator of other channels—in this case ENaC. According to this hypothesis, both normal and CF ASL have plasma-like levels of salt. CFTR mutations eliminate CFTR’s inhibition of ENaC, and because there are significant shunt pathways for Cl–in the airways, increased Na+ transport drives increased absorption of Cl–and water. Thus CF airways display accelerated isotonic fluid absorption that depletes ASL volume and dehydrates mucus, leading to obstruction and infection (15).

How have these two disparate views arisen? The high salt hypothesis. In a clever series of …