131 Albumin Displacement of Oleic Acid from Wound Dressings Promotes an Elastase-Lowering Effect in Chronic Wound Fluid

Abstract

The potential to lower destructively high levels of elastase found in chronic wounds with oleic acid-treated cotton wound dressings was assessed and compared with two types of oleic acid-treated occlusive wound dressings. The ability of albumin to bind oleic acid and transfer elastase inhibitory activity from the dressing material to elastase in solution was examined. Cotton, hydrogel, and hydrocolloid wound dressings were treated with oleic acid and tested for their ability to lower elastase activity. Oleic acid–treated cotton gauzes, hydrogels, and hydrocolloid dressings were found to release oleic acid in the presence of albumin in sufficient quantities to inhibit elastase activity. The order of elastase lowering activity with the three oleic acid-formulated wound dressings was cotton gauze > hydrogel > hydrocolloid. Elastase inhibition by oleic acid displaced from gauze followed a dose response profile. In contrast Cathepsin G, when displaced by albumin, was inhibited within a narrow range of oleic acid formulations. The effect of albumin levels representative of the chronic wound on displacement of oleic acid was determined. Solubilization of cotton bound oleic acid by albumin was found to be most effective at 4% albumin. However, there was sufficient solubilization of oleic acid at the 2% albumin levels found in chronic wound fluid to achieve a significant elastase-lowering effect. Albumin promoted solubilization of oleic acid from cotton with a solubility threshold of 27 mg/g cotton gauze. Equivalent lowering of elastase activity was found with 1%, 2%, and 4% albumin concentrations with oleic acid on cotton at 128 mg oleic acid/gram of cotton.