Figure 7.

The effects of hyperconcentrated mucus on HBE surfaces on nebulized HS (at 8µg NaCl/cm²/min) in inducing ASL volume responses. (A) In the normal (2% mucus) state (solid line), there was a 3-fold increase in ASL volume during nebulization. HBE cultures with hyperconcentrated mucus (12%) (Dashed line) exhibited a 7-fold increase in ASL above baseline ASL. The duration of ASL being increased above basal levels was also increased in hyperconcentrated mucus HBE cultures. (B) Rates of reabsorption (time to baseline ASL, in µm/min) were significantly different between the normal and the hyperconcentrated mucus cultures. P=0.052 by Mann-Whitney Rank Sum Testing. (C) Two sequential doses of HS administered to hyperconcentrated cultures. ASL height difference favors the second dose (p<0.001). (D) Dashed line indicates the expected rise in ASL height if all salt deposited remained on the surface and resulted in an equimolar flux of water into the ASL. Solid line indicates the actual change in ASL height observed during experiments. Compare to Figures 2C–E: In the presence of an intact mucus layer (12% solids), actual and expected ASL height more closely approximated each other early in the HS delivery interval.