Figure 1.

Telomerase activity and telomere length analysis in lung fibroblasts from patients with interstitial lung disease (ILD). Human lung fibroblasts were isolated from control subjects or patients with the indicated diagnoses. Fibroblast lysates were harvested from passage 6–10 cells. (A) Five micrograms of cell lysates were used for a telomerase activity assay with telomerase repeat amplification protocol (TRAP)-ELISA. The samples with absorbance at greater than or equal to 0.25, after subtracting the absorbance reading of the negative control, were considered positive for telomerase activity. The results are shown as percentages of samples that were telomerase-positive in each disease category, with the total number of samples indicated. (B) Genomic DNA from these fibroblasts was analyzed for telomere lengths by terminal restriction fragment (TRF) analysis and Southern blotting. The results are plotted as mean telomere length. The median is indicated with a solid line inside the shaded box, whereas the mean is indicated with a dashed line. The lower error bar indicates the 10th percentile, whereas the upper error bar indicates the 90th percentile. The bottom boundary of the shaded box indicates the 25th percentile, and the upper boundary indicates the 75th percentile. Each data point represents results from cells from a single donor. HP, hypersensitivity pneumonitis; IPF, idiopathic pulmonary fibrosis; NSIP, nonspecific interstitial pneumonia; UIP, usual interstitial pneumonia; SSc, systemic sclerosis.