Making Sense of Electrical Stimulation: A Meta-analysis for Wound Healing

Electrical stimulation as a mode of external enhancement factor in wound healing has been explored widely. It has proven to have multidimensional effects in wound healing including antibacterial, galvanotaxis, growth factor secretion, proliferation, transdifferentiation, angiogenesis, etc. Despite such vast exploration, this modality has not yet been established as an accepted method for treatment. This article reviews and analyzes the approaches of using electrical stimulation to modulate wound healing and discusses the incoherence in approaches towards reporting the effect of stimulation on the healing process. The analysis starts by discussing various processes adapted in in vitro, in vivo, and clinical practices. Later it is focused on in vitro approaches directed to various stages of wound healing. Based on the analysis, a protocol is put forward for reporting in vitro works in such a way that the outcomes of the experiment are replicable and scalable in other setups. This work proposes a ground of unification for all the in vitro approaches in a more sensible manner, which can be further explored for translating in vitro approaches to complex tissue stimulation to establish electrical stimulation as a controlled clinical method for modulating wound healing.

Combining Alginate/PVPI-Based Film with Frequency Rhythmic Electrical Modulation System (FREMS) Technology as an Advanced Strategy for Diabetic Wounds

Diabetes is rising as one of the most diffused diseases of the century with the related urgent necessity to face its systemic and local effects on the patients, such as cardiovascular problems, degeneration of limbs, and dysfunction of the wound healing process. The diffusion of leg ulcers has been estimated to be 1.51 for 1000 population, and these non-resolved wounds can produce several social, economic, and mental health issues in diabetic patients. At the same time, these people experience neuropathic pain that causes morbidity and a further decrease in their quality of life. Here, a new study is presented where asodium alginate/Polyvinylpyrrolidone-Iodine complex (PVPI)-based wound dressing is combined with the Frequency Rhythmic Electrical Modulation System (FREMS) technology, an established medical device for the treatment of neuropathic pain and diabetic ulcers. The produced Alginate/PVPI-based films are characterized in terms of morphology, chemistry, wettability, bio-/hemo-compatibility, and clotting capacity. Next, the Alginate/PVPI-based films are used together with FREMS technology in diabetic mice models, and synergism of their action in the wound closure rate and anti-inflammatory properties is found. Hence, how the combination of electrical neurostimulation devices and advanced wound dressings can be a new approach to improve chronic wound treatment is demonstrated.

The effect of wound electrical stimulation in venous leg ulcer healing-a systematic review

OBJECTIVE

The benefit of using electric stimulation therapy (EST) to heal venous leg ulcers (VLUs) is not well established. The main aim of this systematic review was to evaluate the effects of ulcer EST in VLU healing.

METHODS

A systematic search of the literature was conducted using the databases PubMed, Scopus, and Web of Science and included original studies that reported VLU healing after EST. The inclusion criteria were at least two surface electrodes placed on or near the wound or a planar probe covering the ulcer area to be treated. The Cochrane risk of bias tool for randomized control trials (RCTs) and Joanna Briggs Institute critical appraisal checklist for case series were used to evaluate the risk of bias.

RESULTS

This review included eight RCTs and three case series involving a total of 724 limbs in 716 patients with VLUs. The mean patient age was 64.2 years (95% confidence interval, 62.3-66.2), and 46.2% (95% confidence interval, 41.2%-50.4%) were men. The active electrode was placed on the wound with the passive electrode placed on healthy skin (n = 6), the two electrodes were placed on either side of the wound edges (n = 4), or a planar probe was used (n = 1). The pulsed current was the most used waveform (n = 9). The change in the ulcer size was the main method used to determine ulcer healing (n = 8), followed by the ulcer healing rate (n = 6), exudate levels (n = 4), and the time to healing (n = 3). Five RCTs detected a statistically significant improvement in at least one VLU healing outcome, after EST compared with the control group. In two of these, EST was better than the control but only for patients who had not undergone surgical treatment of VLU.

CONCLUSIONS

The findings from the present systematic review support the use of EST to accelerate wound healing of VLUs, especially for patients who are not surgical candidates. However, the significant variation in electric stimulation protocols represents an important limitation to its use and should be addressed in future studies.

Clinical correlates of pain in adults with hard-to-heal leg ulcers: a cross-sectional study

OBJECTIVE

Pain is a complex symptom associated with hard-to-heal (chronic) leg ulcers that is often poorly managed. The objective of this study was to gain greater understanding by investigating relationships between physical and psychosocial factors, and pain severity in adults with hard-to-heal leg ulcers.

METHOD

A secondary analysis of data collected for a longitudinal, observational study of adults with hard-to-heal leg ulcers was undertaken. Data were collected over a 24-week period, including variables relating to sociodemographics, clinical variables, medical status, health, ulcer and vascular histories, and psychosocial measures. Multiple linear regression modelling was used to determine the independent influences of these variables on pain severity, as measured with a Numerical Rating Scale (NRS).

RESULTS

Of 142 participants who were recruited, 109 met the inclusion criteria for this study, of whom: 43.1% had venous ulcers; 41.3% had mixed ulcers; 7.3% had arterial ulcers; and 8.3% had ulcers from some other cause. The final model explained 37% (adjusted r²=0.370) of the variation in the pain NRS scores. Controlling for analgesic use, salbutamol use (p=0.005), clinical signs of infection (p=0.027) and ulcer severity (p=0.001) were significantly associated with increased pain, while the presence of diabetes (p=0.007) was significantly associated with a decrease in pain.

CONCLUSION

Pain is a highly complex and pervasive symptom associated with hard-to-heal leg ulcers. Novel variables were identified as being associated with pain in this population. The model also included wound type as a variable; however, despite being significantly correlated to pain at the bivariate level of analysis, in the final model, the variable did not reach significance. Of the variables included in the model, salbutamol use was the second most significant. This is a unique finding that, to the authors' knowledge, has not been previously reported or studied. Further research is required to better understand these findings and pain in general.

Electrical stimulation for pain reduction in hard-to-heal wound healing

OBJECTIVE

Despite treatment advances over the past 30 years, the societal impact of hard-to-heal wounds is increasingly burdensome. An unresolved issue is wound pain, which can make many treatments, such as compression in venous leg ulcers, intolerable. The aim of this review is to present the evidence and stimulate thinking on the use of electrical stimulation devices as a treatment technology with the potential to reduce pain, improve adherence and thus hard-to-heal wound outcomes.

METHOD

A literature search was conducted for clinical studies up to August 2020 reporting the effects of electrical stimulation devices on wound pain. Devices evoking neuromuscular contraction or direct spinal cord stimulation were excluded.

RESULTS

A total of seven publications (three non-comparative and four randomised trials) were identified with four studies reporting a rapid (within 14 days) reduction in hard-to-heal wound pain. Electrical stimulation is more widely known for accelerated healing and is one of the most evidence-based technologies in wound management, supported by numerous in vitro molecular studies, five meta-analyses, six systematic reviews and 30 randomised controlled trials (RCTs). Despite this wealth of supportive evidence, electrical stimulation has not yet been adopted into everyday practice. Some features of electrical stimulation devices may have hampered adoption in the past.

CONCLUSION

As new, pocket-sized, portable devices allowing convenient patient treatment and better patient adherence become more widely available and studied in larger RCTs, the evidence to date suggests that electrical stimulation should be considered part of the treatment options to address the challenges of managing and treating painful hard-to-heal wounds.

Bioelectronic properties of DNA, protein, cells and their applications for diagnostic medical devices

From a couple of centuries ago, understanding physical properties of biological material, their interference with their natural host and their potential manipulation for employment as a conductor in medical devices, has gathered substantial interest in the field of bioelectronics. With the fast-emerging technologies for fabrication of diagnostic modalities, wearable biosensors and implantable devices, which electrical components are of essential importance, a need for developing novel conductors within such devices has evolved over the past decades. As the possibility of electron transport within small biological molecules, such as DNA and proteins, as well as larger elements such as cells was established, several discoveries of the modern charge characterization technologies were evolved. Development of Electrochemical Scanning Tunneling Microscopy and Nuclear Magnetic Resonance among many other techniques were of vital importance, following the discoveries made in sub-micron scales of biological material. This review covers the most recent understandings of electronic properties within different scale of biological material starting from nanometer range to millimeter-sized organs. We also discuss the state-of-the-art technology that's been made taking advantage of electronic properties of biological material for addressing diseases like Parkinson's Disease and Epilepsy.

A current affair: electrotherapy in wound healing

New developments in accelerating wound healing can have immense beneficial socioeconomic impact. The wound healing process is a highly orchestrated series of mechanisms where a multitude of cells and biological cascades are involved. The skin battery and current of injury mechanisms have become topics of interest for their influence in chronic wounds. Electrostimulation therapy of wounds has shown to be a promising treatment option with no-device-related adverse effects. This review presents an overview of the understanding and use of applied electrical current in various aspects of wound healing. Rapid clinical translation of the evolving understanding of biomolecular mechanisms underlying the effects of electrical simulation on wound healing would positively impact upon enhancing patient’s quality of life.

High-voltage pulsed current stimulation enhances wound healing in diabetic rats by restoring the expression of collagen, α-smooth muscle actin, and TGF-β1

Impaired wound healing is a common complication of diabetes mellitus and a major morbidity that leads to pain and severely diminished quality of life. Diabetic wounds are commonly associated with defective immune cell responses or abnormality of extracellular matrix. Various types of electrical stimulation interventions have been used to promote tissue healing. However, it is unclear whether high-voltage pulsed current stimulation (HVPCS) enhances diabetic wound healing. In this study, the effects of HVPCS on wound healing were investigated in diabetic rats. Three groups of rats (10 per group) were used: non-diabetic control, diabetic control, and diabetic rats that were administered HVPCS for 40 minutes daily for 1 week. Rats from control groups were administered sham interventions. Dorsal incision wounds were generated in all animals, and wound-healing rate was determined during one-week intervention. After interventions, we measured the relative expression levels of collagen type I (collagen-I), α-smooth muscle actin (α-SMA), and transforming growth factor-β1 (TGF-β1) mRNAs in the wounded skin. Wound closure was delayed in diabetic control rats compared to the non-diabetic control rats, and the diabetic control rats showed the reduced expression levels of collagen-I, α-SMA and TGF-β1 mRNAs. Importantly, compared to diabetic control rats, rats with HVPCS showed accelerated wound closure and healing (p < 0.01) and restored expression levels of collagen-I (p = 0.02), α-SMA (p = 0.04), and TGF-β1 (p = 0.01) mRNAs. In conclusion, HVPCS may be beneficial for enhancing the healing of diabetic wounds by restoring the expression levels of TGF-β1, collagen-I, and α-SMA.

Feasibility of an electrostimulation system treatment for wound healing: a case series of patients with chronic ulcers in Barbados

Major advances have been made in the development of new therapies for chronic wounds. Fenzian™, an electrostimulation system (ES), has been clinically used for a variety of conditions. The ES was recently tested in the Barbadian population for tolerability and acceptability by asthma patients, with encouraging results. Barbados has an estimated 170 people with diabetes having some form of lower-extremity amputation annually. Here, we describe a case series of 21 chronic ulcer patients with diabetes recruited as inpatients (n = 10) and outpatients (n = 11) in a pilot study to evaluate the feasibility and acceptability of ES in the Barbadian population. Results showed statistically significant improvement among those in the inpatient- versus outpatient-recruited group for wound perimeter (P = 0·04), wound surface area (P = 0·03) and wound volume (P = 0·08). We also demonstrate that the improvement continued after cessation of ES treatment. Participants reported increased levels of pain at the end of treatment, and there was no statistically significant change in the reported quality of life. Our results showed greater improvements in reduction of ulcer size for participants from the inpatient- versus outpatient-recruited group.