Wound healing is a complex interplay of numerous growth factors and cytokines and cell types interacting is a complex and highly sensitive process. We can liken these growth factors and cytokines to the musicians in the ‘orchestra’ of wound healing. What most textbooks don’t describe, is how bioelectricity, an important phenomenon across the whole of biology, is responsible for co-ordinating many wound healing processes. If growth factors and cytokines are the musicians in the orchestra, then bioelectricity is the conductor, making sure they are all co-ordinated and working in harmony to restore skin back to pre-wounded state.
But what is bioelectricity? And, what happens when bioelectricity is compromised and the ‘conductor’ isn’t able to do the job properly? These are some of the questions explained in a new paper, published in Wounds Masterclass. The paper explains how something as fundamental and as simple as the movement of ions within tissues, like calcium, potassium, sodium and chloride ions, drives a tiny electrical current, carried by the ions themselves which exist in solution as charged particles. Differences in concentrations of these ions, and negatively charged proteins, inside and outside cells mean that there is a membrane potential across the membrane of every single cell which can be measured in millivolts. Essentially, this means that each cell can act as a tiny battery that stores bioelectricity. Changes to the membrane potential can stimulate changes to cell behaviour. We most often think about this happening in the context of nerve cells being stimulated to fire off a nerve impulse, but in reality these kinds of events happen in all cells in the human body – including the cells that are involved in wound healing.
One long-observed bioelectric phenomenon specifically associated with wounding is known as the ‘current of injury’. Although seldom mentioned in wound management textbooks, this phenomenon has been known to science for over 150 years! The current of injury is a flow of electrical current from the edge of a wound towards the centre of a wound. All cells in tissue at the edge of the wound are exposed to this current of injury which stimulates their activity for several days after wounding. The current of injury is a form of bioelectricity that stimulates essential wound healing events like keratinocyte and fibroblast cell proliferation, migration and differentiation which is achieved via the stimulation of cytokines and growth factors.
In normal wound healing, this wound-induced bioelectricity persists until the wound heals. But what happens in hard-to-heal wounds? The paper goes on to explain that, in some groups of people, for example older people of those with diabetes, the current of injury is lower than in younger or healthy people. This leads to an interesting possibility – that having a compromised current of injury makes the wound healing process less efficient – the conductor of the orchestra is not doing the job properly – and this may be one of the reasons why hard-to-heal wounds are more common in these groups of people. More research is needed, but a compromised current of injury could reasonably be hypothesized as a new ‘barrier to healing’.
Luckily, this particular barrier to healing may have an easy clinical solution. For people more likely to have a reduced current of injury, such as older people, or those with diabetes, one therapeutic option to boost the current of injury is the application of microcurrent electrical stimulation therapy (EST), for example Accel-Heal Solo. Use of EST to stimulate healing and relieve pain is well evidenced in the clinical literature. Whereas previously EST devices were expensive and difficult to use, Accel-Heal is a safe and easy-to-use, device that can be used along-side a patients’ usual treatment and in their own home.
With the burden of hard-to-heal wounds growing, now may be time to consider microcurrent EST as a new angle. Boosting the patient’s natural bioelectrical current of injury through the application of a microcurrent EST device may stimulate healing and reduce pain and give patients the best possible outcome.
This blog is based on:
Martin R. Bioelectric Stimulation, Electric Fields and the Current of Injury: Have We Been Overlooking One of the Most Important Coordinators of the Wound Healing Process? Wounds Masterclass 2024;
This paper is also available on-line.