Am. J. Respir. Crit. Care Med., Vol 153, No. 6, 06 1996, 1918-1923.
Serum indicators of free radical activity in idiopathic pulmonary fibrosis
CI Jack, MJ Jackson, ID Johnston and CR Hind
The University Department of Medicine, University of Liverpool, United Kingdom.
Serum levels of free radical activity were measured in 37 patients with
idiopathic pulmonary fibrosis (IPF) and 16 control subjects. Three assays
used were (1) simultaneously measured levels of the 9,11-diene conjugate of
linoleic acid and 9,12-linoleic acid expressed as a percent molar ratio
(%MR), a measure of free-radical-mediated lipid peroxidation; (2)
thiobarbituric acid reactive substances (TBARS), one of which is
malondialdehyde; (3) desferrioxamine-chelatable iron assay, a measure of
the potential iron available to catalyze free radical generation. Mean %MR,
TBARS and desferrioxamine-chelatable iron were all elevated initially in
patients with IPF compared with control subjects (%MR, p < 0.0001;
TBARS, p = 0.0013; desferrioxamine- chelatable iron, p = 0.0029).
Furthermore, the serum %MR was higher in a subset of patients with
clinically worsening IPF than in those patients with clinically stable
disease (p = 0.002). Treatment did not appear to affect the three different
serum indicators of free radical activity. Thus, lipid peroxidation appears
to be increased in patients with IPF and is associated with an increase in
desferrioxamine- chelatable iron levels. Serum % MR levels appeared to
correlate with clinical disease activity, and they may have a role in
monitoring disease activity.
