Objectives

To examine the acid-base and histological changes in in vivo rabbit cutaneous tissue after electrochemical therapy.

Study design

In vivo rabbit tissue study.

Methods

The shaved skin on the backs of female Oryctolagus cuniculi were assigned to treatments with or without tumescence with normal saline. Two platinum-needle electrodes were inserted into each treatment area and connected to a direct current (DC) power supply. Voltage (3-5 V) was varied and applied for 5 minutes. The wound-healing process was monitored via digital photography and ultrasonography until euthanasia at day 29. Treatment areas were biopsied, and specimens were sectioned through a sagittal midline across both electrode insertion sites. Samples were then evaluated utilizing light microscopy (hematoxylin and eosin, Masson's Trichrome, and Picrosirius red).

Results

Treatment sites developed mild inflammation that dissipated at lower voltages or became scabs at higher voltages. Ultrasonography demonstrated acoustic shadowing with spatial spread that increased with increasing voltage application. The 4- and 5-V sites treated with saline had localized areas of increased tissue density at day 29. Although specimens treated with 3 V did not look significantly different from control tissue, 4- and 5-V samples with and without saline tumescence had finer, less-organized collagen fibers and increased presence of fibrocytes and inflammatory infiltrates.

Conclusions

Electrochemical therapy caused localized injury to in vivo rabbit cutaneous tissue, prompting regenerative wound repair. With future development, this technology may offer precise, low-cost rejuvenation to restore the functionality and appearance of dermal scars and keloids.

Level of evidence

NA Laryngoscope, 131:E2196-E2203, 2021.

Background

Current minimally invasive fat reduction modalities use equipment that can cost thousands of U.S. dollars. Electrochemical lipolysis (ECLL), using low-cost battery and electrodes (approximately $10), creates acid/base within fat (width, approximately 3 mm), damaging adipocytes. Longitudinal effects of ECLL have not been studied. In this pilot study, the authors hypothesize that in vivo ECLL induces fat necrosis, decreases adipocyte number/viability, and forms lipid droplets.

Methods

Two female Yorkshire pigs (50 to 60 kg) received ECLL. In pig 1, 10 sites received ECLL, and 10 sites were untreated. In pig 2, 12 sites received ECLL and 12 sites were untreated. For ECLL, two electrodes were inserted into dorsal subcutaneous fat and direct current was applied for 5 minutes. Adverse effects of excessive pain, bleeding, infection, and agitation were monitored. Histology, live-dead (calcein, Hoechst, ethidium homodimer-1), and morphology (Bodipy and Hoechst) assays were performed on day 0 and postprocedure days 1, 2, 7, 14 (pig 1 and pig 2), and 28 (pig 2). Average particle area, fluorescence signal areas, and adipocytes and lipid droplet numbers were compared.

Results

No adverse effects occurred. Live-dead assays showed adipocyte death on the anode on days 0 to 7 and the cathode on days 1 to 2 (not significant). Bodipy showed significant adipocyte loss at all sites ( P < 0.001) and lipid droplet formation at the cathode site on day 2 ( P = 0.0046). Histology revealed fat necrosis with significant increases in average particle area at the anode and cathode sites by day 14 (+277.3% change compared with untreated, P < 0.0001; +143.4%, P < 0.0001) and day 28 (+498.6%, P < 0.0001; +354.5%, P < 0.0001).

Conclusions

In vivo ECLL induces fat necrosis in pigs. Further studies are needed to evaluate volumetric fat reduction.

Clinical relevance statement

In vivo ECLL induces adipocyte death and fat necrosis. ECLL has the potential to be utilized in body fat contouring.

Body contouring achieved via subcutaneous adipose tissue reduction has notably advanced over the past century, from suction assisted lipectomy to techniques with reduced degrees of invasiveness including laser, radiofrequency, high frequency focused ultrasound, cryolipolysis, and drug-based injection approaches. These costly techniques have focused on damaging adipocyte cell membranes, hydrolyzing triglycerides (TGs), or inducing apoptosis. Here, we present a simple, low-cost technique, termed electrochemical lipolysis (ECLL). During ECLL, saline is injected into the subcutaneous adipose tissue, followed by insertion of needle electrodes and application of an electrical potential. Electrolysis of saline creates localized pH gradients that drive adipocyte death and saponification of TGs. Using pH mapping, various optical imaging techniques, and biochemical assays, we demonstrate the ability of ECLL to induce acid and base injury, cell death, and the saponification of triglycerides in ex vivo porcine adipose tissue. We define ECLL's potential role as a minimally-invasive, ultra-low-cost technology for reducing and contouring adipose tissue, and present ECLL as a potential new application of an emerging electrochemical redox based treatment modality.