351. Cleaved cytokeratin-18 is a mechanistically informative biomarker in idiopathic pulmonary fibrosis.
- Author
-
Cha SI, Ryerson CJ, Lee JS, Kukreja J, Barry SS, Jones KD, Elicker BM, Kim DS, Papa FR, Collard HR, and Wolters PJ
- Subjects
- Aged, Apoptosis, Biomarkers metabolism, Case-Control Studies, Endoplasmic Reticulum Stress, Epithelial Cells metabolism, Epithelial Cells pathology, Female, Humans, Idiopathic Pulmonary Fibrosis pathology, Male, Middle Aged, Pulmonary Alveoli metabolism, Pulmonary Alveoli pathology, Idiopathic Pulmonary Fibrosis diagnosis, Idiopathic Pulmonary Fibrosis metabolism, Keratin-18 metabolism
- Abstract
Background: Stress of the endoplasmic reticulum (ER) leading to activation of the unfolded protein response (UPR) and alveolar epithelial cell (AEC) apoptosis may play a role in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Our objectives were to determine whether circulating caspase-cleaved cytokeratin-18 (cCK-18) is a marker of AEC apoptosis in IPF, define the relationship of cCK-18 with activation of the UPR, and assess its utility as a diagnostic biomarker., Methods: IPF and normal lung tissues were stained with the antibody (M30) that specifically binds cCK-18. The relationship between markers of the UPR and cCK-18 was determined in AECs exposed in vitro to thapsigargin to induce ER stress. cCK-18 was measured in serum from subjects with IPF, hypersensitivity pneumonitis (HP), nonspecific interstitial pneumonia (NSIP), and control subjects., Results: cCK-18 immunoreactivity was present in AECs of IPF lung, but not in control subjects. Markers of the UPR (phosphorylated IRE-1α and spliced XBP-1) were more highly expressed in IPF type II AECs than in normal type II AECs. Phosphorylated IRE-1α and cCK-18 increased following thapsigargin-induced ER stress. Serum cCK-18 level distinguished IPF from diseased and control subjects. Serum cCK-18 was not associated with disease severity or outcome., Conclusions: cCK-18 may be a marker of AEC apoptosis and UPR activation in patients with IPF. Circulating levels of cCK-18 are increased in patients with IPF and cCK-18 may be a useful diagnostic biomarker.
- Published
- 2012
- Full Text
- View/download PDF