COLLAGEN CONCENTRATION AND RATES OF SYNTHESIS IN IDIOPATHIC PULMONARY FIBROSIS

Abstract

To define the biochemical correlates of the apparent morphologic increase in lung interstitial collagen in idiopathic pulmonary fibrosis (IPF), collagen content was quantitated, and the morphologic degree of fibrosis was assessed in 9 patients with IPF and 6 control subjects. There were no significant differences in the collagen content among patients with IPF compared to that of control subjects. There was no correlation between collagen content and the morphologic assessment of the degree of fibrosis. Analysis of the collagen content from multiple sites made from base to apex of postmortem material from 3 patients with IPF and 2 control subjects demonstrated a wide, but similar, variation in collagen content in both groups; no definite pattern of anatomic distribution was found in IPF or control subjects. Collagen and noncollagen protein synthesis rates in IPF patients'' lung explants demonstrated no significant differences compared to those of the control subjects. Apparently IPF is a disease of an alteration in quality, form and location of collagen rather than simply a disease of increased interstitial collagen.