Chronic wounds differ from normal acute wounds, because they do not go through the normal healing process of inflammation, proliferation, and remodelling; instead they stop at the inflammation stage, and the healing process is stopped completely. Chronic wounds often require amputations, and may lead to death.
Chronic wounds are associated with other health problems including diabetes, obesity, and poor circulation; thus, it is more prevalent in developed countries. It is estimated that 1-2% of the population in developed countries will experience a chronic wound during their lifetime. In the US alone, there are over six million chronic wound patients, and treatment is costing around $25 billion per year. However there has been many important breakthroughs recently in the field of treating chronic wounds.
First, a biotechnology company in Iceland named Kerecis Ltd. has developed ways to treat wounds using materials made from fish skin. The company’s products have already been approved by the FDA, and it can be used to treat acute, chronic, and oral wounds. The company’s products are made from drying and processing cod skin. Fish skin is naturally rich in omega-3 fatty acids, which yield anti-inflammatory effects that can speed up the healing process. The material substitutes the extracellular matrix crucial for healing and lacking in chronic wound patients.
The extracellular matrix is composed of a variety of polysaccharides, water, and collagen proteins, and the scaffolding provided by the matrix recruits cells which proliferate, differentiate, and eventually turn into living tissue.
Another recent discovery was the importance of miRNA in chronic wound healing. MicroRNAs or miRNAs are short non-coding RNA sequences that can participate in regulating gene expression, through post transcriptional silencing of mRNAs. Recently miRNA has been found to be involved in many different diseases, and chronic wounds is no different. Indeed, it was found that miRNA levels in normal acute and chronic wound healing differs; thus, the under-expression and over-expression of certain miRNAs are responsible for disrupting the normal stages of wound healing. The miRNAs involved in wound healing are being discovered, and this provides the possibility of gene therapy for patients. However, it is not yet a valid therapy, as there needs to be a suitable delivery system of drugs that can overcome intracellular and extracellular barriers.
Lastly, technology that targets the microenvironment around the wound has been proven to accelerate the healing process. This involves using lactic acid bacteria as vectors to produce and deliver a human chemokine (signalling proteins) to the site of the wound. The specific chemokine being upregulated is CXCL12, and its degradation is slowed, as the lactic acid produced by the bacteria lowers the pH. The resulting change in the microenvironment leads to more immune cells gathering, and they also become more specialised, producing more TGFß, a growth factor involved in healing. Overall, there are exciting prospects for the future of treating chronic wounds, although some technology is still in the developmental stage, they are showing great promise. Chronic wounds still affects millions of patients, and the technologies discussed in this article may provide a cure for them.