Wound healing is a complex process orchestrated by tiny electrical currents.1 In hard to heal wounds, the electrical signals are believed to be weaker than in healthy skin, and it is widely believed that this dysfunction contributes to failure to heal.2 This is where microcurrent electrical stimulation therapy (EST) comes in – this innovative wound treatment can boost the electrical signals that are missing from a compromised wound bed and improve the rate of healing.
But what effect does microcurrent EST have on cells in the wound bed? Normal wound-related bioelectric currents are known to stimulate cell migration, proliferation and differentiation, which are all essential behaviours that drive the healing process.1 Building on decades of research using cultured human cells exposed to tiny electrical stimuli, the renowned A*STAR Skin Research Labs in Singapore recently reported a new study to explore in depth the effects of Accel-Heal, a commercially available, microcurrent EST device, on epidermal repair. This research, conducted using a benchtop wound model using cultured human skin, sought to further unravel the mysteries of how electrical stimulation influences the healing process at the cellular level.
The study used a scaled-up 3-dimensional skin wound model, tailored to accommodate the Accel-Heal device. The model was composed of human dermis seeded with human keratinocytes. Once the models had grown to maturity, they were wounded with a 4mm puncher and treated. The effects of EST were evaluated after 4 and 7 days of treatment, and compared with control models which were fitted with a device that was not switched on.
One key benefit of this model was that the impacts of Accel-Heal could be measured in different ways. Firstly, the size of the wound could be measured over time, to monitor how quickly it shrank in size. Secondly, by taking cross-sections of the model, the distance over which keratinocytes had migrated over the top of a wounded dermis, the length of the “epithelial tongues”, could be precisely measured. The quality of the newly formed epidermis could also be observed.
Results revealed a sizable stimulatory effect of EST. Wounds exposed to EST for 4 days healed faster (mean 65.8% wound shrinkage) compared to control wounds (mean 49.7%). What’s more, after 4 days of treatment, in the EST-exposed wounds, the epithelial tongues covered over half the wound surface (mean 50.3%), whereas, in control wounds, only a quarter (mean 26.2%) of the wound surface had been re-epithelialised. These results demonstrated that microcurrent EST had stimulated keratinocyte migration and proliferation compared to control wounds which were not treated. This finding was confirmed by the increased immunohistochemical staining for cell markers of proliferation (Ki-67 and p63). The study also found increased keratinocyte differentiation in models treated with Accel-Heal (increased keratin-10 staining) a necessary aspect of rebuilding the layers in a healthy epidermis. Unexpectedly, the researchers also observed a firmer attachment and deeper integration of the newly formed epidermis in wounds exposed to Accel-Heal. This appeared as deeper cell projections into the dermis and less epithelial detachment in models treated with Accel-Heal compared to controls. This suggests the intriguing possibility that microcurrent EST may improve not only the speed of healing but the quality of healing too. These findings shed some light on why some clinicians and patients report better than expected skin or scar quality after healing with Accel-Heal, which gives them more confidence that their wound will not breakdown again.4
We already knew from a multitude of randomised controlled trials that EST can stimulate wound healing in the clinic.3 This new research has contributed to our evolving understanding of how microcurrent EST devices like Accel-Heal produce this effect. The research has also hinted at an intriguing new benefit of microcurrent EST – that it may also improve the quality of the healed skin. As we continue to unravel the secrets of EST, and Accel-Heal in particular, this valuable wound model may provide us with a deeper understanding, paving the way for greater therapeutic acceptance in wound care.
Graphical abstracts created by Jing Yi Gan. (ASRL)
The results described in this blog are based on:
Lim LKP, Balakrishnan Y, Goh G, Tham KC, Ng YZ, Lunny DP, Leavesley D, Bonnard C. Automated electrical stimulation therapy accelerates re-epithelialization in a 3D in vitro human skin wound model. Adv Wound Care (New Rochelle). 2023 Dec 7. doi: 10.1089/wound.2023.0018.
This paper is available on-line.
References:
1. Tyler SEB. Nature’s Electric Potential: A Systematic Review of the Role of Bioelectricity in Wound Healing and Regenerative Processes in Animals, Humans, and PlantsFront Physiol. 2017 Sep 4;8:627
2. Nuccitelli R, et al. The electric field near human skin wounds declines with age and provides a noninvasive indicator of wound healing. Wound Repair Regen. 2011;19(5): 645–655
3. Avendaño-Coy J, et al. Electrical microcurrent stimulation therapy for wound healing: A meta-analysis of randomized clinical trials. J Tissue Viability. 2021 Dec 4:S0965-206X(21)00132-7
4. Louisson P. et al. Management of recurrent venous leg ulcer with electroceutical therapy* to improve pain, expedite healing and reduce risk of recurrence. Poster presented at EWMA 2015, May, London.