Chronic Wound Healing

Authors: Hasan Gökcer Tekin MD., Christian Kaare Paaskesen Med.Stud., Dorte Barrit, Diploma of Health, Specialist nurse in wound care, and Magnus Avnstorp, MD

Theory

In most chronic wound an imbalance of inflammatory cytokines and high protease activity keeps the wound in a prolonged inflammatory phase. The inflammatory stimuli in chronic wounds are kept in a steady state by repeated trauma (cell necrosis) by factors such as ischemia and bacterial colonization. Mitogenic factors such as PDGF are decreased in chronic wounds compared with acute wounds. Pro-inflammatory cytokines (TNF-α, interleukines, TGF–β) and proteases (MMP) are elevated in chronic wounds resulting in continuous degradation and breakdown of extracellular matrix. This breakdown of extracelluar matrix initiates a new cycle of inflammation and locks the wound in a chronic inflammatory state. By preparing the wound bed (active debridement of non-vital tissue and bacterial colonization) and treating causal ischemic factors, this inflammatory cycle can be broken.

Multiple important factors differ in chronic and acute wounds:

Acute wounds	Chronic Wounds
High level of mitogenic factors	Low level of mitogenic factors
Decreased levels of inflammatory cytokines	High levels of inflammatory cytokines
Low protease activity	High protease activity