Study of free iron and pyridinoline in hypertrophic scars and normal skin.

In order to investigate the possible involvement of free radicals in the formation of hypertrophic scar, normal skin sections were subjected in vitro to a free radical generating system and the pyridinoline levels determined by enzyme-linked immunoassay. Pyridinoline concentration increased from 5.123 pmol/mg wet weight to 8.760 pmol/mg wet weight after treatment with a free radical generating system. Free iron, a catalyst for the generation of hydroxyl radicals from hydrogen peroxide, was found to be significantly higher in hypertrophic scar tissue (n = 6, mean 50.70 ng/mg wet weight) compared to normal skin (n = 12, mean 7.89 ng/mg wet weight, P = 0.0093, unpaired t-test). It is hypothesised that the occurrence of increased pyridinoline cross-links in hypertrophic scar tissue may result from free radical generation related to inflammatory processes. Further work is necessary to test this hypothesis, but these results suggest that it is tenable.