Skin sponge soaks up inflammatory chemicals to promote healing
A hydrogel-based dressing, chemically tweaked so it can selectively soak up inflammatory signals but leave pro-healing growth factors untouched, has been developed by scientists in Germany.
Chronic wounds, like the ulcers suffered by diabetics and patients with vascular diseases, or skin infections following severe burns, are a major health burden internationally.
In these conditions, a vicious cycle of inflammation causing tissue damage, which leads to further inflammation and ultimately impaired or delayed healing, produces a state of deadlock where wounds can "smoulder" and fail to resolve for years.
One of the drivers of this process is the cocktail of pro-inflammatory signals released by the immune system at sites of injury. So Nadine Lohmann, from the University of Leipzig, wondered whether selectively soaking up some of these factors could help to tip the balance more in favour of wound repair and healing.
She and her colleagues have chemically modified a dressing material called a hydrogel, a light, water rich matrix impregnated with star-shaped "sticky" molecules of poly-ethylene glycol and glycosaminoglycans.
These grabbed and sequestered 80% of the inflammatory signals present in test media, and significantly reduced the numbers of immune cells attracted to samples in a culture dish.
Used on animals with skin wounds, including diabetic mice that develop chronic infections and poor healing like human patients, the new dressings produced significantly more rapid healing.
Importantly, despite removing pro-inflammatory signals from the wounds, the dressings did not promote the growth of infecting bacteria such as Staph aureus.
Although the team have not yet tested their system directly on human patients, they were able to collect samples of fluid exuding from people with skin wounds, including from chronic and infected leg ulcers.
These were applied to test samples of the dressing, which locked away the inflammatory hormones but, encouragingly, did not affect the concentrations of growth-factors critical for healing.
Since the components of the new dressings are already used in a range of existing therapeutics, translating the new findings to the clinic should be a relatively speedy process.