The
vacuum-assisted closure (VAC) device causes microdeformations of the
wound surface in contact with the foam. Because angiogenesis and
matrix metalloproteinase (
MMP) activity are altered in chronic
wounds, we hypothesized that microdeformations stimulate capillary formation and affect
MMP activity. A VAC device was used to deliver microdeformational
wound therapy (MDWT) to the chronic
wounds of 3 debilitated patients. Debrided tissue was obtained from
wound areas with and without foam contact. Microvessel density and
MMP activity were determined by immunohistochemistry and zymography, respectively. Microvessel density of MDWT-treated
wounds was 4.5% (+/-0.8) compared with areas not covered by foam [1.6% (+/-0.1)] (P = 0.05) during the first week of treatment and 2.7% (+/-0.3) compared with untreated tissue [1.3% (+/-0.1)] (P = 0.03) during the second treatment week.
Wounds subjected to MDWT had greater microvessel density compared with the same
wound prior to treatment [1.5% (+/-0.3)] (P = 0.02).
MMP-9/NGAL (
neutrophil gelatinase-associated lipocalin), MMP-9, latent MMP-2, and active MMP-2 were reduced by 15%-76% in MDWT-treated
wounds. MDWT provides a favorable wound-healing environment by increasing angiogenesis and decreasing
MMP activity in chronic
wounds.