CFTR and cystic fibrosis: Taken together, we believe our findings are consistent with a scenario (see Figure 8) in which two major factors act synergistically to favor the development of skeletal muscle dysfunction in CF: 1) a higher ambient level of pulmonary/systemic inflammation leading to greater exposure of the muscles to pro-inflammatory mediators; and 2) a greater inherent sensitivity of the muscles (related to their lack of CFTR) to the effects of pro-inflammatory mediator exposure.