052 Effect of Negative Pressure Wound Therapy on the Expression of TNF-α, IL-1β, MMP-2, MMP-3, and TIMP-1 in Wound Fluid of Adults with Pressure Ulcers

Introduction:  Negative pressure wound therapy (NPWT) is an established treatment of chronic wounds. There is limited understanding of the molecular biological mechanisms of NPWT. The purpose of this study was to characterize changes in the biochemical composition of wound fluid collected from chronic pressure ulcer wounds in adults treated with NPWT. Methods:  Nine stage III or IV pressure ulcer patients scheduled for NPWT (V.A.C.® Therapy, KCI, San Antonio, TX) were recruited. Their ages ranged between 30 and 99. Concentrations of cytokines (IL-1β, TNF-α), metalloproteinases (MMP-2, MMP-3), and tissue inhibitor of metalloproteinase (TIMP)-1 in wound fluids were measured at baseline and after 1 day, 3 days, and 7 days of continuous NPWT. Results:  At days 1, 3, and 7, TNF-α levels were significantly and comparably lower than baseline (p < 0.05). MMP- 3 levels significantly decreased from baseline at days 1 and 3 (p < 0.05) and significantly increased from baseline at day 7 (p < 0.05) with continuous NPWT. IL-1β levels significantly increased at day 3 (p < 0.05). There were no significant differences in TIMP-1 or MMP-2 levels at any of the time points when compared to baseline. Discussions and Conclusions:  A key finding of this study is that with NWPT, reductions in levels of the proinflammatory cytokine, TNF-α, from baseline levels were observed and this effect was sustained for at least 1 week. This, together with effects on IL-1 and MMP-3, may be an indication that the NPWT has a rapid and sustained effect on the inflammatory state of chronic wounds. Further studies are being conducted to expand sample size and to analyze other wound healing indicators.