Premature senescence in cultured skin fibroblasts from subjects with cystic fibrosis.

Cultured skin fibroblasts from subjects with cystic fibrosis exhibited normal population doubling 
times in early passages. After about 13 cumulative population doublings, cystic 
fibrosis lines doubled more slowly than controls and ceased doubling after 
about 19 weekly passages. Control lines continued doubling for 27 passages. 
The premature senescence noted in cells from subjects with cystic fibrosis 
reconciles controversial observations of cell doubling reported in the literature. Data 
presented here demonstrate that experiments with cystic fibrosis cells in late 
passage may generate misleading results since differences from control lines may 
be ascribed to generalized senile changes rather than to specific results 
of the cystic fibrosis genotype. 