522 J WOCN ■ September/October 2011 Copyright © 2011 by the Wound, Ostomy and Continence Nurses Society Copyright © 2011 Wound, Ostomy and Continence Nurses Society. Unauthorized reproduction of this article is prohibited. WOUND CARE Effect of Oxidized Regenerated Cellulose/Collagen Matrix on Proteases in Wound Exudate of Patients With Diabetic Foot Ulcers Dietmar Ulrich  Ralf Smeets  Frank Unglaub  Michael Wöltje  Norbert Pallua PURPOSE: The aim of this study was to investigate the inﬂuence of oxidized regenerated cellulose/collagen matrix on the con- centration and activity of gelatinases, elastase, and plasmin in wound exudate. SUBJECTS AND SETTING: The study included 32 patients with dia- betic foot ulcers. Ten patients with a mean age of 66  9 years (mean  SD) were treated with hydrocolloid dressings; 22 patients with a mean age of 57  12 years were treated with oxidized regenerated/collagen matrix and hydrocolloid dressings. METHODS: Wound exudate was collected on days 0, 5, 14, and every 14 days thereafter for 12 weeks. Total protein was deter- mined according to Bradford’s technique. The levels of elastase and plasmin were measured spectroﬂuorometrically. Besides, gelatinase activity and matrix metalloproteinase-2 concentration were analyzed. The surface area of all ulcers was measured by planimetry. RESULTS: Patients treated with oxidized regenerated cellulose/ collagen matrix showed a signiﬁcant decrease in elastase, plasmin, and gelatinase activities in wound exudates. The matrix metal- loproteinase-2 concentration was signiﬁcantly reduced on days 14, 28, 42, and 56 in comparison to day 0. Furthermore, wound size was signiﬁcantly reduced at days 14 and 28 in oxidized regenerated cellulose/collagen matrix-treated patients (P  .05). CONCLUSION: Our results showed a signiﬁcant and immediate reduction in the levels of all tested proteases in the wound exudate of diabetic foot ulcer patients treated with oxidized regenerated cellulose/collagen matrix. These patients also experienced a signiﬁcantly greater reduction in wound size. ■ Introduction Foot ulcers are one of the most common complications of diabetes mellitus. It not only is a typical complication in later stages of diabetes but can also occur in patients with newly diagnosed disease. 1 Despite the postulations of the St Vincent Declaration, which stated that within 5 years the amputation rate should be reduced by 50%, there are 30,000 amputations reported each year in Germany due to diabetic foot ulcers. 2-11 Normal wound healing relies on a balance between the processes that lead to new tissue formation and processes necessary to remove damaged tissue. Tissue formation and removal are regulated by growth factors and proteases that control the biologic processes necessary to achieve normal wound repair. 12 Abnormalities in the levels of growth fac- tors and proteases are thought to be one of the factors con- tributing to wound chronicity and failure to heal. 13 This hypothesis is supported by studies of diabetic foot ulcers, which consistently reveal persistent inﬂammation and an imbalance in protease/protease-inhibitor levels. 14 Alterations in the levels of these regulatory factors can lead to a non- healing state and the formation of a chronic wound. 15 Chronic wounds fail to follow the normal pattern of wound repair, which involves inﬂammation, granulation, J Wound Ostomy Continence Nurs. 2011;38(5):522-528. Published by Lippincott Williams & Wilkins  Dietmar Ulrich, MD, PhD, Department of Plastic and Reconstructive Surgery, Erasmus University Hospital, Rotterdam, The Netherlands.  Ralf Smeets, MD, DDS, PhD, Interdisciplinary Centre of Clinical Research “BIOMAT”.  Frank Unglaub, MD, PhD, Department of Plastic Surgery, Hand Surgery, Burn Unit, University Hospital Aachen, Pauwelsstrasse 30, Aachen, Germany.  Michael Wöltje, PhD, Department of Plastic Surgery, Hand Surgery, Burn Unit, University Hospital Aachen, Pauwelsstrasse 30, Aachen, Germany.  Norbert Pallua, MD, PhD, Department of Plastic Surgery, Hand Surgery, Burn Unit, University Hospital Aachen, Pauwelsstrasse 30, Aachen, Germany. Dietmar Ulrich and Ralf Smeets contributed equally to the study. Correspondence: Ralf Smeets, MD, DDS, PhD, Interdisciplinary Centre of Clinical Research “BIOMAT,” University Hospital Aachen, Pauwelsstrasse 30, Aachen D-52074, Germany (rasmeets@ukaachen.de). DOI: 10.1097/WON.0b013e31822ad290