Recent advances and emerging treatmentsBMJ 2006; 332 doi: https://doi.org/10.1136/bmj.332.7547.962 (Published 20 April 2006) Cite this as: BMJ 2006;332:962
- Stuart Enoch, research fellow,
- Joseph E Grey,
- Keith G Harding
- Royal College of Surgeons of England and is based at the Wound Healing Research Unit, Cardiff University.
The healing of acute wounds involves a complex and dynamic series of events leading to the repair of injured tissues. These events, triggered by tissue injury, involve four overlapping but well defined phases: haemostasis, inflammation, proliferation, and remodelling.
Haemostasis is secured by platelet aggregation and clot formation. The inflammatory phase begins with the arrival of phagocytic neutrophils and, later, macrophages at the wound site; they are important sources of and substrates for growth factors. The proliferative phase is characterised by the formation of new blood vessels (angiogenesis), synthesis of extracellular matrix components such as collagen, granulation tissue formation, and re-epithelialisation. The extracellular matrix is continually remodelled during the final phase; an avascular scar is the end result of the healing process.
Chronic wounds may be arrested in any of the four phases; commonly, however, disruption occurs in the inflammatory or the proliferative phases. Many mediators—including inflammatory cells, growth factors, proteases such as matrix metalloproteinases (MMPs), and cellular and extracellular elements—play important roles in different stages of the healing process. Alterations in one or more of these components may account for the impaired healing observed in chronic wounds.
Biological based treatments
Cryopreserved human cadaver skin (used in the UK), and human amniotic membrane and frog skin (used in other parts of the world) have long been used to treat wounds, particularly burns. More recently, artificial “skin substitutes” and growth factors have been developed to help achieve healing in chronic, non-healing wounds of varying aetiologies. These treatments target different stages of the healing process and, in the case of skin substitutes, replace lost tissue.
Artificial skin substitutes, products of tissue engineering, consist of a microengineered, biocompatible, polymer matrix in combination with cellular and/or extracellular …