Effect of High- and Low-Frequency Transcutaneous Electrical Nerve Stimulation on Angiogenesis and Myofibroblast Proliferation in Acute Excisional Wounds in Rat Skin. Adv Skin Wound Care. 2016;29:357-363. [PMID: 27429241 DOI: 10.1097/01.asw.0000488721.83423.f3]

Nanofiber-reinforced chitosan/gelatine hydrogel with photothermal, antioxidant and conductive capabilities promotes healing of infected wounds

The wound healing process was often accompanied by bacterial infection and inflammation. The combination of electrically conductive nanomaterials and wound dressings could accelerate cell proliferation through endogenous electrical signaling, effectively promoting wound healing. In this study, polypyrrole was modified with dopamine hydrochloride by an in situ polymerization to form dopamine-polypyrrole (DA-Ppy) conductive nanofibers which successfully enhanced the water dispersibility and biocompatibility of polypyrrole. The DA-Ppy nanofibers were dispersed in an aqueous solution for >48 h and still maintained good stability. In addition, the DA-Ppy nanofibers showed good photothermal properties, and the temperature could reach 59.7 °C by 1.5 W/cm2 near-infrared light irradiation (NIR) for 10 min. DA-Ppy conductive nanofibres could be well dispersed in 3,4-dihydroxyphenylpropionic acid modified chitosan-carboxymethylated β-cyclodextrin modified gelatin (CG) hydrogel due to the presence of DA, which endowed CG/DA-Ppy hydrogel with good adhesion properties, and the hydrogel adhered to the pigskin would not be dislodged by washing with running water. Under NIR, the CG/DA-Ppy hydrogel showed significant antimicrobial properties. Moreover, the CG/DA-Ppy hydrogel had excellent biocompatibility. In addition, CG/DA-Ppy hydrogel was effective in scavenging ROS, inducing macrophage polarization towards the M2 phenotype, and modulating the level of wound inflammation in vitro. Finally, it was confirmed in rat-infected wounds that the tissue regeneration effect and collagen deposition in the CG/DA-Ppy + NIR group were significantly better than the other groups in the repair of infected wounds, indicating better repair of infected wounds. The results suggested that the photothermal, antioxidant DA-Ppy conductive nanofiber had great potential for application in infected wound healing.

Current Therapeutic Modalities for the Management of Chronic Diabetic Wounds of the Foot

Impaired wound healing is common in patients with diabetes mellitus (DM). Different therapeutic modalities including wound debridement and dressing, transcutaneous electrical nerve stimulation (TENS), nanomedicine, shockwave therapy, hyperbaric (HBOT) and topical (TOT) oxygen therapy, and photobiomodulation (PBM) have been used in the management of chronic diabetic foot ulcers (DFUs). The selection of a suitable treatment method for DFUs depends on the hosts' physiological status including the intricacy and wound type. Effective wound care is considered a critical component of chronic diabetic wound management. This review discusses the causes of diabetic wounds and current therapeutic modalities for the management of DFUs, specifically wound debridement and dressing, TENS, nanomedicine, shockwave therapy, HBOT, TOT, and PBM.

Electric Factors in Wound Healing

Significance: Electric factors such as electric charges, electrodynamic field, skin battery, and interstitial exclusion permeate wound healing physiology and physiopathology from injury to re-epithelialization. The understanding of how electric factors contribute to wound healing and how treatments may interfere with them is fundamental for the development of better strategies for the management of pathological scarring and chronic wounds. Recent Advances: Angiogenesis, cell migration, macrophage activation hemorheology, and microcirculation can interfere and be interfered with electric factors. New treatments with various types of electric currents, laser, light emitting diode, acupuncture, and weak electric fields applied directly on the wound have been developed to improve wound healing. Critical Issues: Despite the basic and clinical development, pathological scars such as keloids and chronic wounds are still a challenge. Future Directions: New treatments can be developed to improve skin wound healing taking into account the influence of electrical charges. Monitoring electrical activity during skin healing and the influence of treatments on hemorheology and microcirculation are examples of how to use knowledge of electrical factors to increase their effectiveness.

Non-invasive physical therapy as salvage measure for ischemic skin flap: A literature review

This review focuses on the available evidence regarding the molecular mechanisms and treatment potential of several non-surgical physical therapies for managing flap ischemia to propose a non-invasive, economical, and simple treatment to improve flap survival. A review of the literature was conducted on the topics of various non-invasive methods for the treatment of ischemic necrosis of the distal end of the flap between 1988 and 2019. A total of 52 published studies were reviewed on the applications of hyperbaric oxygen therapy, electrical stimulation therapy, heat stress pretreatment, phototherapy, and vibration therapy to manage skin flap necrosis. The underlying molecular mechanisms of these physical therapies on revitalizing the dying skin flaps were discussed and preliminary clinical uses of these therapies to salvage the necrotic skin flaps were pooled and summarized for clarifying the safety and feasibility of these methods. Various physical therapy regimens have been ushered to manage necrotic development in cutaneous flaps. With the refinement of these new technologies and enhancement of related basic science research on vascular revitalization, the prevention and treatment of flap ischemia will enter a new era.

Bioactive polymeric materials and electrical stimulation strategies for musculoskeletal tissue repair and regeneration

Electrical stimulation (ES) is predominantly used as a physical therapy modality to promote tissue healing and functional recovery. Research efforts in both laboratory and clinical settings have shown the beneficial effects of this technique for the repair and regeneration of damaged tissues, which include muscle, bone, skin, nerve, tendons, and ligaments. The collective findings of these studies suggest ES enhances cell proliferation, extracellular matrix (ECM) production, secretion of several cytokines, and vasculature development leading to better tissue regeneration in multiple tissues. However, there is still a gap in the clinical relevance for ES to better repair tissue interfaces, as ES applied clinically is ineffective on deeper tissue. The use of a conducting material can transmit the stimulation applied from skin electrodes to the desired tissue and lead to an increased function on the repair of that tissue. Ionically conductive (IC) polymeric scaffolds in conjunction with ES may provide solutions to utilize this approach effectively. Injectable IC formulations and their scaffolds may provide solutions for applying ES into difficult to reach tissue types to enable tissue repair and regeneration. A better understanding of ES-mediated cell differentiation and associated molecular mechanisms including the immune response will allow standardization of procedures applicable for the next generation of regenerative medicine. ES, along with the use of IC scaffolds is more than sufficient for use as a treatment option for single tissue healing and may fulfill a role in interfacing multiple tissue types during the repair process.

Effectiveness of Transcutaneous Electrical Nerve Stimulation Energy in Older Adults: A Pilot Clinical Trial

OBJECTIVE

To evaluate the effectiveness of a transcutaneous electric nerve stimulation (TENS) device typically used for pain suppression (analgesia) during pressure injury (PI) healing, peripheral vascularization, and secondary pain in older adults with chronic PIs and cognitive impairment.

DESIGN AND SETTING

This pilot clinical trial followed patients from 6 nursing homes.

PATIENTS AND INTERVENTION

Twenty-two patients with PIs in the distal third of their lower limbs (7 men, 15 women) were included in this study. The control group completed standard wound care (SWC), whereas the experimental group received SWC and TENS. A total of 20 sessions were conducted for each group over 2 months, 3 times a week.

MAIN OUTCOME MEASURE

PI area, PI healing rate, blood flow, skin temperature, oxygen saturation, and level of pain at baseline and posttreatment.

MAIN RESULTS

Significant improvements were achieved in PI area (mean difference, 0.92; 95% confidence interval [CI], 0.15-1.67; P =.024), healing rate (3; 95% CI, 1-4.99; P =.009), skin temperature (1.82; 95% CI, 0.35-3.28; P =.021), and pain (1.44; 95% CI, 0.49-2.39; P =.008) in the experimental group, whereas none of the variables revealed a significant change in the control group.

CONCLUSIONS

The effect of local and spinal TENS combined with the SWC for PI produced a significant improvement in size, healing, skin temperature, and pain levels.

Angiogenic effects of low-intensity cathodal direct current on ischemic diabetic foot ulcers: A randomized controlled trial

AIMS

This study investigated the effect of low-intensity cathodal direct current (CDC) of electrical stimulation (ES) on the release of hypoxic inducible factor-1α (HIF-1α), nitric oxide (NO), vascular endothelial growth factor (VEGF), and soluble VEGF receptor-2 (sVEGFR-2) in the wound fluid of ischemic diabetic foot ulcers (DFUs).

METHODS

This study was a randomized, single-blind, placebo-controlled trial. Thirty type 2 diabetes patients with ischemic foot ulcerations were randomly assigned to receive either low-intensity CDC at sensory threshold (ES group, n=15) or placebo treatment (control group, n=15) for 1h/day, 3days/week, for 4weeks (12 sessions). After debridement during the first and twelfth treatment sessions, wound fluid was collected before and after ES application to determine the levels of HIF-1α, NO, VEGF, and sVEGFR-2. Wound surface area (WSA) was measured at the first, sixth, and twelfth sessions.

RESULTS

At the first session, after ES application, wound-fluid levels of HIF-1α were significantly increased (+61.98pg/mL) compared to the control group (-3.85pg/mL, P=0.01). After ES application at the first and twelfth sessions, wound-fluid levels of VEGF were also significantly increased (+36.77 and +39.57pg/mL, respectively) compared to the control group (+4.15 and +0.15pg/mL, P=0.007 and P=0.019, respectively). There was no significant effect on NO and sVEGFR-2 levels between the groups.

CONCLUSIONS

Low-intensity CDC has positive effects on the release of HIF-1α and VEGF in the wound area of ischemic DFUs. Furthermore, our results suggest that applying ES to ischemic DFUs can be a promising way to promote angiogenesis and to achieve better outcomes in diabetic wound healing.