Treatment of chronic wounds is a continuing clinical problem and socio-economic burden with diabetic foot ulcers alone costing the NHS £300 million a year.
Scientists in Bristol have found that human foetal stem cells can effectively be used to treat back leg ischaemic ulcers in a model of type 1 diabetes.
The researchers also found the culture in which the stem cells had been grown mimicked the wound-healing ability of the cells, suggesting that they could be used as a "factory" of wound-healing substances. Alternatively, the active ingredients in the culture, once identified, could be used instead; this would avoid the ethical concerns of using human foetal stem cells.
In humans, diabetic patients with ischaemic foot ulcers have the worst outcome of all chronic skin wounds, with higher amputation and mortality rates than patients carrying non-ischaemic ulcers. Topical gels containing single growth factors have recently been used with some success in non-ischaemic ulcers, but have been unsuccessful in ischaemic ulcers, which are also resistant to other conventional treatment. Ischaemia results when the blood supply to a tissue is greatly reduced or stopped - this can occur in diabetes since it can also cause impaired blood flow in patients.
The healing activity of stem cells is recognised for their ability to separate into the various component cells of injured tissues, as well as to discharge growth factors that may encourage the formation of new blood vessels in the patient.
Paolo Madeddu, Professor of Experimental Cardiovascluar Medicine and colleagues at the Bristol Heart Institute, previously used stem cells in models of back leg ischaemia, showing that foetal stem cells could be more therapeutically effective than adult stem cells.
Foetal stem cells possess a better ability to multiply and to graft onto host tissue, and to separate into other cell types to replace those in the damaged tissue. The group led by Bristol University's Professor Madeddu have found that foetal stem cells accelerate the closure of ischaemic diabetic ulcers, while stem cells from blood of adult donors are ineffective.
Professor Madeddu, commenting on the research, said: "This is the first study to demonstrate the healing capacity of local therapy with CD133+ stem cells in a model of diabetic ischaemic foot ulcer. The foetus-derived cells would be difficult to obtain for therapeutic applications. However, the finding that conditioned culture is also effective in stimulating wound healing may have important implications for the cure of the ischaemic complications of diabetes.
"Foetal CD133+ cells might be used in the future as a "factory" of therapeutic substances. Alternatively, synthetic replica of the conditioned medium could be produced to obviate ethical concerns surrounding the direct use of foetal stem cells."
Karen Addington, Chief Executive of Juvenile Diabetes Research Foundation (JDRF), added: "Chronic wounds and diabetic foot ulcers are serious long-term complications of type 1 diabetes. Because of the difficulties involved in managing type 1 diabetes, people living with the condition are at an increased risk of requiring a non-traumatic limb amputation. Although more work needs to be done before we can begin to think about potential new treatments, this research represents a useful way to help identify new strategies for dealing with type 1 diabetes."