EUROPEAN  TISSUE  REPAIR  SOCIETY

INTRODUCTION

Dr George W Cherry
Department of Dermatology, Churchill Hospital,
Headington, Oxford OX3 7LJ, England

The European Tissue Repair Society has had a number of focus or consensus meetings on subjects ranging from wound debridement to wound pharmacology since its founding more than twelve years ago. These focus meetings have been very successful in concentrating on specific aspects of tissue repair. In fact some of these meetings have led to consensus statements which have become part of clinical practice.

The role of wound bed preparation, or the status of the wound bed in influencing or predicting success of healing, is still not fully understood, and in retrospect has been debated as being the cause of failure of some of the new therapies available, such as growth factors.

There are a number of clinical questions that still need to be resolved, such as: bacterial burden, wound fluid, matrix metalloproteinases, methods of measurement and assessment, antiseptics, and different methods of wound debridement. These are all part of this meeting’s programme and, hopefully, this will lead to a better understanding of this complex part of wound healing management, which could result in a future meeting held in conjunction with the European Tissue Repair Society’s Annual Meeting on the subject of wound bed preparation.

Professor Keith Harding
Director, Wound Healing Research Unit,
The Medi Centre, Cardiff, CF14 4UJ, Wales

Traditionally clinicians have focused on healing as a measure of success following any intervention that they have provided to patients with wounds. It is increasingly recognised at the various stages of healing that the wounds progressed through various stages of healing and the single end point may be too crude to identify other benefits conveyed to patients. The main objective of this meeting is to debate the discussion whether wound bed preparation is an important key component of treating wounds and whether there is any concensus among clinicians and research staff as to what this means and how best to achieve it in a range of clinical settings.

Dr Richard Taylor and Mr Tim James
Department of Clinical Biochemistry, John Radcliffe Hospital,
Headington, Oxford OX3 9DU, England

Wound fluid represents the extracellular fluid of tissue undergoing repair and regeneration and is considered an exudate derived from plasma. As it contains locally produced tissue products it can provide an insight into the biochemical and cellular microenvironment of the wound bed. Collection techniques for wound fluid are variable and will affect the quantity and quality of wound fluid obtained. Many studies involve collection of fluid from beneath occlusive dressings, in others fluid is collected on to filter paper. Further work needs to be undertaken to validate optimal procedures.

Sequential sampling studies with acute wound fluid (AWF) in both experimental animals and in patients undergoing surgical procedures have provided information about the sequence of biochemical changes in normal wound repair. Most studies of chronic wound fluid (CWF) have been undertaken to understand the pathophysiology of impaired healing.

Analysis of CWF collected from patients with venous disease has identified components which may be at inadequate concentrations to drive reparative processes or are directly detrimental to wound repair. The chronic wound environment has been shown to be hypoxic, with elevated lactate and low glucose. Studies of healing and non-healing CWF wound suggest that increased inflammatory mediators are probably a greater problem than deficiencies of growth factors. Much work has focused on the proteolytic nature of wound fluid and differences in both the type and quantity of proteases exist between AWF and CWF. In particular, matrix metalloproteinases are implicated in prolonged healing.

More recently the role oxidative stress plays in impaired healing has been investigated and markers (allantoin: urate % ratio and 8-isoprostane) in CWF would support the involvement of reactive oxygen species in chronicity of wounds.

Some measures in CWF may be of predictive value for healing outcome but no markets have yet been fully evaluated. Growth factors and cytokines demonstrate large inter individual variation and are unlikely candidates. It may be that a simple market such as albumin, total protein or C-reactive protein might provide an insight into the potential of the wound bed to progress to healing.

References:

1. Trengrove NJ, Langton SR, Stacey MC, Biochemical analysis of wound fluid from non-healing and healing chronic leg ulcers. Wound Rep Reg 1996; 4: 234–239.
2. James TJ, Hugh MA, Cherry GW, Taylor RP. Simple biochemical markets in the assessment of chronic wounds. Wound Rep Reg 2000; 8: 264–269.
3. Trengrove NJ, Stacey MC, MacAuley S, Bennett N, Gibson J, Burslem F, Murphy G, Schultz G. Analysis of the acute and chronic wound environemnts: the role of proteases and their inhibitors. Wound Rep Reg 1999; 7: 442–52.
4. Trengrove NJ, Bielefeldt-Ohmann H, Stacey MC. Mitogenic activity and cytokine levels in non-healing and healing chronic leg ulcers. Wound Rep Reg 2000; 8: 13–25.