Selective pick-up of increased iron by deferoxamine-coupled cellulose abrogates the iron-driven induction of matrix-degrading metalloproteinase 1 andlipid peroxidation in human dermal fibroblasts in vitro: A new dressing concept

Using atomic absorption spectrum analysis, we found iron levels in exudates from chronic wounds to be significantly increased (3.71 +/- 1.56 mu mol pe r g protein) compared to wound fluids from acute wounds derived from bliste r fluids (1.15 +/- 0.62 mu mol per g protein, p < 0.02), drainage fluids of acute wounds (0.87 +/- 0.34 <mu>mol per g protein, p < 0.002), and pooled human plasma of 50 volunteers (0.42 <mu>mol per g protein). Increased free iron and an increase in reactive oxygen species released from neutrophils r epresent pathogenic key steps that - via the Fenton reaction - are thought to be responsible for the persistent inflammation, increased connective tis sue degradation, and lipid peroxidation contributing to the prooxidant host ile microenvironment of chronic venous leg ulcers. We herein designed a sel ective pick-up dressing for iron ions by covalently binding deferoxamine to cellulose. No leakage occurred following gamma sterilization of the dressi ng and, more importantly, the deferoxamine-coupled cellulose dressing retai ned its iron complexing properties sufficient to reduce iron levels found i n chronic venous ulcers to levels comparable to those found in acute wounds . In order to study the functionality of the dressing, human dermal fibrobl asts were exposed to a Fenton reaction mimicking combination of 220 muM Fe( III) citrate and 1 mM ascorbate resulting in a 4-fold induction of matrix-d egrading metalloproteinase 1 as determined by a matrix-degrading metallopro teinase 1 specific enzyme-linked immunosorbent assay. This induction was co mpletely suppressed by dissolved deferoxamine at a concentration of 220 muM or by an equimolar amount of deferoxamine immobilized to cellulose. In add ition, the Fe(III) citrate and ascorbate driven Fenton reaction resulted in an 8-fold increase in malondialdehyde, the major product of lipid peroxida tion, as determined by high pressure liquid chromatography, This increase i n malondialdehyde levels could be significantly reduced in the presence of the selective pick-up dressing coupled with deferoxamine suggesting that th e deferoxamine dressing, in fact, prevents the development of a damaging pr ooxidant microenvironment and also protects front unfavorable consequences like matrix-degrading metalloproteinase 1 and lipid peroxide induction.