Streaming of Proteolytic Enzyme Solutions for Wound Debridement: A Feasibility Study

Tali Yaakobi, PhD; Dalit Roth, MSc; Yoram Chen, BSc; Amihay Freeman, PhD

Disclosures

Wounds. 2004;16(6) 

In This Article

Abstract and Introduction

The effective enzymatic digestion of extracellular matrix for the preparation of cell cultures paved the way to its application for skin treatment and wound debridement, encouraged by the selectivity observed for the separation of dermis from epidermis or the removal of necrotic tissue from wound bed without damage to healthy tissue. Proteases, such as papain and collagenase, mostly formulated as ointments, were successfully employed for wound debridement, achieved within several days of repeated treatments. Here, we propose and provide feasibility demonstration of a new mode of enzyme application for skin treatment and wound debridement: continuous controlled streaming of enzyme solutions onto an enclosed treated area. The working hypothesis is that the combination of fresh supply of enzymes in optimal working buffer with continuous flow will substantially shorten the time required for effective treatment, e.g., from days or weeks to hours, as well as simplify handling and processing. The feasibility of enzyme streaming and its efficacy are demonstrated in targeted selective intact skin digestion, removal of coagulated blood, and debridement of experimental burn wounds in lab animals. Selective skin digestion and burn wound debridement with minimal handling were readily achieved within 2 to 3 hours by streaming diluted protease solutions at slow flow rates. This simple and straight-forward mode of operation carries potential for the improvement of wound bed management. The use of this streaming technique may facilitate delivery of cleaning solutions, enzymatic debriders, or irrigation fluids for wound bed preparation.

Enzymatic digestion of the intercellular matrix for the separation of mammalian cells is a common methodology in the preparation of primary cell cultures.[1] This procedure, resulting in suspended isolated cells, has been routinely employed for the preparation of cell cultures from a wide spectrum of organs, including skin.[2] Some of the proteases used in these procedures were demonstrated to be selective in disruption of the extracellular matrix and adhesion proteins without causing cell damage.[3,4] Furthermore, separation of dermis from epidermis[2,4,5] and the removal of necrotic or damaged tissue from wounds and burns without damage to healthy tissue were also demonstrated.[6,7] These observations paved the way to systematic exploration of the potential inherent in wound debridement by enzymes. Most of these studies employed commercially available enzymes (e.g., papain, bromelain, collagenase, trypsin, thermolysin) with only few attempts to identify or develop new enzymes, e.g., from the antarctic krill.[6,7,8]

Enzymes tested for effective wound debridement were mostly formulated as ointments, solutions absorbed by a wet gauze, hydrocolloids, or hydrogels.[3,6,7] Comparative studies on the efficacy of wound debridement by enzyme-containing ointments—either animal models or humans—indicated efficacy dependence on the enzyme employed: While fibrinolysin ointment was found ineffective, collagenase ointment gave some improvement, and papain-urea ointment was identified as most effective from this group.[9,10,11,12] Prolonged time was required for these treatments to deliver significant improvement, ranging from four days to three weeks with daily wound treatments for fresh ointment supply (for the first 4-7 days of treatment).[9,10,11,12]

The objective of this study was to test the feasibility of a new mode of enzyme delivery for skin treatment and wound debridement—continuous controlled streaming of enzyme solutions onto the targeted treated area. The working hypothesis was that the combination of a fresh supply of enzymes in an optimal working buffer with continuous flow would substantially shorten the time required for effective enzymatic skin treatment or wound debridement. Furthermore, the slightly pressurized stream would allow homogeneous supply of the enzyme to all parts of the treated area and may remove cells, debris, and solubilized proteins.

In this report, the feasibility of enzyme streaming and its efficacy was studied regarding intact skin digestion, removal of coagulated blood, and debridement of experimental surgical and burn wounds.

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