In vitro stimulation with radiofrequency currents promotes proliferation and migration in human keratinocytes and fibroblasts

Radiofrequency Currents Modulate Inflammatory Processes in Keratinocytes

Keratinocytes play an essential role in the inflammatory phase of wound regeneration. In addition to migrating and proliferating for tissue regeneration, they produce a large amount of cytokines that modulate the inflammatory process. Previous studies have shown that subthermal treatment with radiofrequency (RF) currents used in capacitive resistive electric transfer (CRET) therapy promotes the proliferation of HaCat keratinocytes and modulates their cytokine production. Although physical therapies have been shown to have anti-inflammatory effects in a variety of experimental models and in patients, knowledge of the biological basis of these effects is still limited. The aim of this study was to investigate the effect of CRET on keratinocyte proliferation, cytokine production (IL-8, MCP-1, RANTES, IL-6, IL-11), TNF-α secretion, and the expression of MMP9, MMP1, NF-κB, ERK1/2, and EGFR. Human keratinocytes (HaCat) were treated with an intermittent 448 kHz electric current (CRET signal) in subthermal conditions and for different periods of time. Cell proliferation was analyzed by XTT assay, cytokine and TNF-α production by ELISA, NF-κB expression and activation by immunofluorescence, and MMP9, MMP1, ERK1/2, and EGF receptor expression and activation by immunoblot. Compared to a control, CRET increases keratinocyte proliferation, increases the transient release of MCP-1, TNF-α, and IL-6 while decreasing IL-8. In addition, it modifies the expression of MMPs and activates EGFR, NF-κB, and ERK1/2 proteins. Our results indicate that CRET reasonably modifies cytokine production through the EGF receptor and the ERK1/2/NF-κB pathway, ultimately modulating the inflammatory response of human keratinocytes.

Bioelectret Materials and Their Bioelectric Effects for Tissue Repair: A Review

Biophysical and clinical medical studies have confirmed that biological tissue lesions and trauma are related to the damage of an intrinsic electret (i.e., endogenous electric field), such as wound healing, embryonic development, the occurrence of various diseases, immune regulation, tissue regeneration, and cancer metastasis. As exogenous electrical signals, such as conductivity, piezoelectricity, ferroelectricity, and pyroelectricity, bioelectroactives can regulate the endogenous electric field, thus controlling the function of cells and promoting the repair and regeneration of tissues. Materials, once polarized, can harness their inherent polarized static electric fields to generate an electric field through direct stimulation or indirect interactions facilitated by physical signals, such as friction, ultrasound, or mechanical stimulation. The interaction with the biological microenvironment allows for the regulation and compensation of polarized electric signals in damaged tissue microenvironments, leading to tissue regeneration and repair. The technique shows great promise for applications in the field of tissue regeneration. In this paper, the generation and change of the endogenous electric field and the regulation of exogenous electroactive substances are expounded, and the latest research progress of the electret and its biological effects in the field of tissue repair include bone repair, nerve repair, drug penetration promotion, wound healing, etc. Finally, the opportunities and challenges of electret materials in tissue repair were summarized. Exploring the research and development of new polarized materials and the mechanism of regulating endogenous electric field changes may provide new insights and innovative methods for tissue repair and disease treatment in biological applications.

Effects of RF Electric Currents on Hair Follicle Growth and Differentiation: A Possible Treatment for Alopecia

Androgenic alopecia (AGA) is the most common type of alopecia and its treatments involve drugs that have various adverse effects and are not completely effective. Radiofrequency-based therapies (RF) are an alternative for AGA treatment. Although there is increasing clinical evidence of the effectiveness of RF for alopecia, its effects at the tissue and cellular level have not been studied in detail. The objective of this study was to analyze ex vivo the potential effect of RF currents used in capacitive resistive electrical transfer (CRET) therapy on AGA. Hair follicles (HFs) were donated by patients with AGA and treated with CRET. AGA-HFs were exposed in vitro to intermittent 448 kHz electric current in subthermal conditions. Cell proliferation (Ki67), apoptosis (TUNEL assay), differentiation (β-catenin), integrity (collagen and MMP9), thickness of the epidermis surrounding HF, proportion of bulge cells and melanoblasts in AGA-HF were analyzed by immunohistochemistry. CRET increased proliferation and decreased death of different populations of AGA-HF cells. In addition, the melanoblasts increased in bulge and the epidermis surrounding the hair follicle thickened. These results support the effectiveness of RF-based therapies for the treatment of alopecia. However, clinical trials are necessary to know the true effectiveness of CRET therapy and other RF therapies for AGA treatment.

Electric currents of 448 kHz upregulate anti-senescence pathways in human dermal fibroblasts

BACKGROUND

Currently, finding new therapeutic strategies that reduce skin aging is a challenge for dermatologists and aesthetic doctors. In recent years, physical therapies have been included in the options for antiaging treatments; however, the biological bases of such treatments have scarcely been studied. One of these physical therapies is capacitive-resistive electric transfer (CRET) therapy. Previous studies have shown that subthermal treatment with CRET promotes the proliferation and migration of various cell types involved in skin regeneration, such as human ADSC (stem cells), fibroblasts, or keratinocytes.

OBJECTIVE

This study investigates the effects of in vitro treatment with CRET-Std (standard, non-modulated signal) or CRET-Mod (modulated signal) on cell proliferation and migration, markers of aging, and extracellular matrix production.

METHODS

Three types of human dermal fibroblasts were used: neonatal fibroblasts (HFn), replicative senescent fibroblasts (HFs), and adult fibroblasts (HFa). The effects of electric stimulation on cell proliferation and migration were studied through XTT and wound closure assays, respectively. The expression of the aging marker β-galactosidase was assessed using a colorimetric assay, whereas immunoblot, immunofluorescence, and ELISAs were carried out to analyze the expression levels of migration, aging, and extracellular matrix proteins.

RESULTS

The treatment with CRET-Std increased HFn and HFa proliferation, as well as migration in the three types of fibroblasts studied compared to those of the controls. Conversely, CRET-Mod did not modify either of these two processes with respect to the controls. Additionally, CRET-Std also reduced the cellular senescence markers β-gal, vimentin, p53, and p21 in all three types of human skin fibroblasts. In addition, the application of CRET-Std also induced fibronectin production in HFn and was able to stimulate ECM neocollagenesis.

CONCLUSION

CRET treatment improves a number of functions related to migration and proliferation, and it reduces age-related cellular changes in human dermal fibroblasts. Therefore, the use of this CRET therapy to reduce the signs of dermal aging and to promote tissue regeneration could be of interest.

Combined Bipolar Radiofrequency and Non-Crosslinked Hyaluronic Acid Mesotherapy Protocol to Improve Skin Appearance and Epidermal Barrier Function: A Pilot Study

BACKGROUND

Age-associated changes in epidermal hydration, pigmentation, thickness and cell renewal influence skin appearance and can lead to laxity, dryness and poor skin tone. The aim of this pilot study was to assess the synergistic effects of a new bipolar radiofrequency plus non-crosslinked hyaluronic acid (HA) mesotherapy protocol compared with radiofrequency alone on skin appearance and markers of epidermal function.

METHODS

This prospective, single-center, split-face pilot study recruited women aged 25-65 years with dryness and laxity of the facial skin defined by a trans-epidermal water loss (TEWL) value of ≥26 g/m2/h. Subjects were treated with a bipolar radiofrequency device on both sides of the face. This was immediately followed by needle hyaluronic acid (HA) treatment on one side of the face with 2.5 mL of a non-crosslinked HA. Photographic documentation, analysis of epidermal barrier function parameters, and high frequency (HF) ultrasound analysis were performed prior to treatment and at 28 days.

RESULTS

Twenty female subjects with a mean age of 46 (range 29 to 54) years and dry and lax facial skin were included. TEWL was reduced and skin hydration improved to a greater extent with the combined radiofrequency plus mesotherapy protocol compared with radiofrequency alone (-5.8% vs. +3.9% and +23.1% vs. +1.0%, respectively). The combined protocol was also associated with greater improvements in melanin (-7.5% vs. -1.5%) and erythema values (-7.2% vs. +3.0%), respectively. Ultrasound measures of epidermal thickness and epidermal density were greater after the combined protocol compared with radiofrequency alone (12.0% vs. 5.6% and 57.7% vs. 7.1%, respectively). Both treatments were well-tolerated.

CONCLUSIONS

The combined bipolar radiofrequency and HA mesotherapy protocol provided greater improvements in skin hydration, firmness and tone compared with radiofrequency alone. The combination treatment was also associated with greater epidermal thickness and density and increased keratinocyte differentiation suggesting a synergistic effect of both treatments on epidermal homeostasis and barrier function. Both treatments were well-tolerated and led to improvements in facial appearance.

Anti-Fibrotic Effects of RF Electric Currents

Hypertrophic scars and keloids are two different manifestations of excessive dermal fibrosis and are caused by an alteration in the normal wound-healing process. Treatment with radiofrequency (RF)-based therapies has proven to be useful in reducing hypertrophic scars. In this study, the effect of one of these radiofrequency therapies, Capacitive Resistive Electrical Transfer Therapy (CRET) on biomarkers of skin fibrosis was investigated. For this, in cultures of human myofibroblasts treated with CRET therapy or sham-treated, proliferation (XTT Assay), apoptosis (TUNEL Assay), and cell migration (Wound Closure Assay) were analyzed. Furthermore, in these cultures the expression and/or localization of extracellular matrix proteins such as α-SMA, Col I, Col III (immunofluorescence), metalloproteinases MMP1 and MMP9, MAP kinase ERK1/2, and the transcription factor NFκB were also investigated (immunoblot). The results have revealed that CRET decreases the expression of extracellular matrix proteins, modifies the expression of the metalloproteinase MMP9, and reduces the activation of NFκB with respect to controls, suggesting that this therapy could be useful for the treatment of fibrotic pathologies.

Comparison of resistive capacitive energy transfer therapy on cadaveric molars and incisors with and without implants

Capacitive–resistive energy transfer therapy (CRet) is used to improve the rehabilitation of different injuries. This study aimed to evaluate and compare the changes in temperature and current flow during different CRet applications on upper and lower molars and incisors, with and without implants, on ten cryopreserved corpses. Temperatures were taken on molars and incisors with invasive devices and skin temperature was taken with a digital thermometer at the beginning and after treatments. Four interventions: 15 VA capacitive hypothermic (CAPH), 8 watts resistive (RES8), 20 watts resistive (RES20) and 75 VA capacitive (CAP75) were performed for 5 min each. All treatments in this study generated current flow (more than 0.00005 A/m²) and did not generate a significant temperature increase (p > 0.05). However, RES20 application slightly increased surface temperature on incisors without implants (p = 0.010), and molar with (p = 0.001) and without implant (p = 0.008). Also, CAP75 application increased surface temperature on molars with implant (p = 0.002) and upper incisor with implant (p = 0.001). In conclusion, RES8 and CAPH applications seem to be the best options to achieve current flow without an increase in temperature on molars and incisors with and without implants.

Efficacy of capacitive resistive monopolar radiofrequency in the physiotherapeutic treatment of chronic pelvic pain syndrome: A randomized controlled trial

AIM

To evaluate the efficacy of adjuvant, capacitive resistive monopolar radiofrequency (CRMRF, INDIBA) treatment at 448 kHz together with physiotherapeutic techniques compared to a sham treatment with the same techniques, for pain reduction and quality of life (QoL) improvements in patients with chronic pelvic pain syndrome (CPPS).

METHODS

A triple-blind, randomized controlled trial (RCT) including patients with CPPS randomly allocated (1:1) to a CRMRF-activated group (intervention) or a CRMRF-deactivated one (control). Both groups received physiotherapeutic techniques and pain education weekly for 10 consecutive weeks. Data from a visual analogical scale and the SF-12 questionnaire were collected at trial commencement and repeated at the 5th and 10th sessions. Pain intensity was considered the main outcome. For the comparisons between variables, the χ² and Student's t test were used. Superiority was analyzed by estimating the mean change (95% confidence interval). Analysis was performed for the per-protocol and the intention-to-treat populations. The statistical significance level was set at p < 0.05.

RESULTS

Eighty-one patients were included (67.9% women) with a mean age of 43.6 years (SD 12.9). CRMRF lessened pain scores by more than 2 points and improved QoL by 5 points. There were no relevant side effects and overall adherence to the treatment was 86.4%.

CONCLUSIONS

This is the first RCT that evaluates the efficacy of CRMRF (INDIBA) compared to a sham treatment, and demonstrates its superiority in decreasing pain and improving QoL. Such results may lead to greater prescribing of CRMRF when treating CPPS patients.