A Review Of Transcutaneous Electrical Nerve Stimulation (TENS)

Since Roman times electricity has been used as a means of obtaining pain relief. Even so, there is still no clear explanation of how this mechanism actually works. In this review article the author looks at the historical development of the pain-relieving properties of electricity and how the electrical stimulator has been developed to meet this need. The results from a comparative evaluation of 18 battery-powered transcutaneous nerve stimulators are discussed and the desirable features are outlined.     

Transcutaneous Electrical Nerve Stimulation and Postoperative Use of Narcotic Analgesics

Transcutaneous electrical nerve stimulation (TENS) has been reported to reduce the use of narcotic analgesic medication for pain relief in the postoperative period. This study compares the use of narcotic analgesics and the occurrence of postoperative complications in 205 patients who underwent gastric bypass surgery for control of obesity. Seventy-four patients used TENS for postoperative pain relief. The control group comprised 131 patients who did not use TENS. There were no statistically significant differences in the use of narcotic analgesic medication and the occurrence of postoperative complications between the experimental group and the control group.     

Recombinant Hepatocyte Growth Factor Accelerates Cutaneous Wound Healing in a Diabetic Mouse Model

We examined effects of recombinant hepatocyte growth factor (HGF) on cutaneous wound healing, using a full-thickness cutaneous excision model in diabetic mice. Topical administration of HGF, as well as basic fibroblast growth factor (bFGF), promoted the rate of wound closure and re-epithelialization. Both HGF and bFGF enhanced expansion of the granulation tissue and stimulated neovascularization on day 7 postwounding, wherein the increase in microvessel density in HGF-treated wounds was higher than that in bFGF-treated wounds. Matrix metalloproteinases (MMP-2 and MMP-9) activities involved in cell migration, angiogenesis, and extracellular matrix (ECM) remodeling, were enhanced by HGF-treatment on day 7. On day 28 postwounding (later stages of wound healing), granulation tissue in bFGF-treated wounds remained to a greater extent than that seen in saline- and HGF-treated wounds. Likewise, bFGF- but not HGF-treatment stimulated DNA synthesis of fibroblasts in granulation tissue, suggesting that HGF stimulates wound healing with lesser degree of susceptibility to cutaneous scarring. We propose that supplement of HGF may be a potential therapeutic approach for treatment of cutaneous ulcer.     

Topical Estrogen Accelerates Cutaneous Wound Healing in Aged Humans Associated with an Altered Inflammatory Response

The effects of intrinsic aging on the cutaneous wound healing process are profound, and the resulting acute and chronic wound morbidity imposes a substantial burden on health services. We have investigated the effects of topical estrogen on cutaneous wound healing in healthy elderly men and women, and related these effects to the inflammatory response and local elastase levels, an enzyme known to be up-regulated in impaired wound healing states. Eighteen health status-defined females (mean age, 74.4 years) and eighteen males (mean age, 70.7 years) were randomized in a double-blind study to either active estrogen patch or identical placebo patch attached for 24 hours to the upper inner arm, through which two 4-mm punch biopsies were made. The wounds were excised at either day 7 or day 80 post-wounding. Compared to placebo, estrogen treatment increased the extent of wound healing in both males and females with a decrease in wound size at day 7, increased collagen levels at both days 7 and 80, and increased day 7 fibronectin levels. In addition, estrogen enhanced the strength of day 80 wounds. Estrogen treatment was associated with a decrease in wound elastase levels secondary to reduced neutrophil numbers, and decreased fibronectin degradation. In vitro studies using isolated human neutrophils indicate that one mechanism underlying the altered inflammatory response involves both a direct inhibition of neutrophil chemotaxis by estrogen and an altered expression of neutrophil adhesion molecules. These data demonstrate that delays in wound healing in the elderly can be significantly diminished by topical estrogen in both male and female subjects.     

Advances in the Modulation of Cutaneous Wound Healing and Scarring

Cutaneous wounds inevitably heal with scars, which can be disfiguring and compromise function. In general, the greater the insult, the worse the scarring, although genetic make up, regional variations and age can influence the final result. Excessive scarring manifests as hypertrophic and keloid scars. At the other end of the spectrum are poorly healing chronic wounds, such as foot ulcers in diabetic patients and pressure sores. Current therapies to minimize scarring and accelerate wound healing rely on the optimization of systemic conditions, early wound coverage and closure of lacerations, and surgical incisions with minimal trauma to the surrounding skin. The possible benefits of topical therapies have also been assessed. Further major improvements in wound healing and scarring require an understanding of the molecular basis of this process. Promising strategies for modulating healing include the local administration of platelet derived growth factor (PDGF)-BB to accelerate the healing of chronic ulcers, and increasing the relative ratio of transforming growth factor (TGF)beta-3 to TGFbeta-1 and TGFbeta-2 in order to minimize scarring.     

Transcutaneous electrical nerve stimulation (TENS) increases survival of ischaemic musculocutaneous flaps

The effect of transcutaneous electrical nerve stimulation (TENS) on the survival of a dorsal musculocutaneous flap was studied in the rat. Postoperative TENS treatment significantly increased the flap survival area in groups of rats receiving different modes of TENS. The flap survival area was up to 95% in the TENS-treated groups compared with 33-45% in the control groups. Repeated (3 days) high intensity (20 mA), high-frequency (80 Hz) TENS applied segmentally at the base of the flap was shown to be the most effective treatment in increasing the flap survival. Preoperative TENS did not increase flap survival area compared with untreated controls. It is concluded that postoperative TENS treatment markedly increases the experimental flap survival area and may be of clinical value for treatment of local ischaemia.     

The Vagus Nerve and Nicotinic Receptors Involve Inhibition of HMGB1 Release and Early Pro-inflammatory Cytokines Function in Collagen-Induced Arthritis

Objectives  

The cholinergic anti-inflammatory pathway, a vagus nerve-dependent mechanism, inhibits cytokine releases in models of acute inflammatory disease. We investigated the efficacy and elucidated the possible mechanism of the cholinergic anti-inflammatory pathway on collagen-induced arthritis (CIA) in mice.     

Transcutaneous electrical nerve stimulation (TENS) of upper cervical nerve (C2) for the treatment of somatic tinnitus

Somatic tinnitus has been defined as tinnitus temporally associated to a somatic disorder involving the head and neck. Several studies have demonstrated the interactions between the somatosensory and auditory system at the dorsal cochlear nucleus (DCN), inferior colliculus, and parietal association areas. The objective is to verify the effect of transcutaneous electrical nerve stimulation of the upper cervical nerve (C2) in the treatment of somatic tinnitus. As electrical stimulation of C2 increases activation of the DCN through the somatosensory pathway and enlarges the inhibitory role of the DCN on the central nervous system, C2 TENS can be considered for tinnitus modulation. A total of 240 patients in whom tinnitus is modulated by somatosensory events (e.g., tinnitus change with rotation, retro- and antiflexion of neck) or modulated by pressure on head or face were included in this study. Both a real and a sham TENS treatment were applied for 30 min (10 min of 6 Hz, followed by 10 min of 40 Hz and 10 min of sham). Significant tinnitus suppression was found (P < 0.001). Only 17.9% (N = 43) of the patients with tinnitus responded to C2 TENS. They had an improvement of 42.92%, and six patients had a reduction of 100%.     

Electrical Vagus Nerve Stimulation and Nicotine Effects in Peritonitis-Induced Acute Lung Injury in Rats

The cholinergic anti-inflammatory pathway has been identified as playing a key role in the communication between the central nervous system and the immune system during inflammation. The potential beneficial role of vagus nerve stimulation (VNS) remains to be clarified in established sepsis. We hypothesized that VNS or nicotine administration would reduce lung injury and mortality in established sepsis. We conducted a prospective, randomized experimental study. Four hours after peritonitis induction by cecal ligation and puncture (CLP), rats were randomized into three groups of seven animals according to the intervention: control group, VNS group (15 V, 2 ms, 5 Hz during 20 min), and nicotine group (400 μg/kg intraperitoneal). Survival was determined as lung injury score 4 and 8 h after CLP. Tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-10, cytokine-induced neutrophil chemoattractant (CINC)-3 and thrombin–antithrombin complexes (TATc) were measured at baseline and at 4 and 8 h after CLP. Survival at 8 h was 71.4%, 100%, and 23.8% in the control, VNS, and nicotine groups, respectively (p < 0.05). All animals had lung damage but without significant difference between groups even if nicotine-treated animals tended to have a higher score than the controls (p = 0.09). Neutrophil polymorphonuclear (PMN) infiltration was more pronounced in the nicotine group compared with the VNS group (p = 0.015) but not with the controls. TNF-α, IL-6, IL-10, CINC-3, and TATc were elevated in all groups (NS). In this model of established sepsis, posttreatment by VNS was associated with increased survival, while nicotine administration increased lung PMN infiltration and mortality. Nicotine-induced bacterial clearance impairment and nicotine systemic effects may explain these observations.     

Cerebral Dynamics of SEPs to Non-Painful and Painful Cutaneous Electrical Stimulation of the Thenar and Hypothenar

Early, middle and late latency somatosensory evoked potentials (SEPs) elicited by cutaneous electrical stimulation (painful vs. non-painful) of right and left hands were recorded. The aims were to study (1) if lifelong use of dominant right hand would result in different SEP topographies compared to non-dominant left hand stimulation, (2) if painful and non-painful stimuli resulted in different SEP activation patterns for the different latency components and (3) if these results were consistent between two areas of the hand. Electrical stimuli were applied cutaneously above the thenar and hypothenar muscles of the left and right hand. A two-way repeated measures ANOVA was used to test the effects of laterality and intensity for a given peak amplitude and latency. Statistical results yielded no significant difference in peak amplitude for either thenar and hypothenar between the two hands. In contrast, a significant difference in amplitude was observed for 6 components for each stimulus location when the two intensities were compared. These components were found at early, middle and late latencies. No significant latency shift was observed between the two hands. Only the P30 component showed a significant latency shift for both locations with the painful condition having the shorter latency. Thus, life-long use of the dominant hand does not generate detectable changes in cortical evoked activity to sensory input from the skin above thenar and hypothenar muscles. Several SEP components across the time course (0-400 ms) showed increased amplitude when the stimulus was increased from non-painful to painful intensity.     

Effect of Low-Power Laser (LPL) and Light-Emitting Diode (LED) on Inflammatory Response in Burn Wound Healing

The aim of the study was to investigate the biochemical and molecular changes in the process of epidermal healing of burn injuries after therapeutic treatment with low-power laser (LPL) and light-emitting diode (LED). Rats were divided into six groups: skin without injury (Sham), burn wounds (BWs), BW?+?660-nm LPL, BW?+?904-nm LPL, BW?+?632-nm LED, and BW?+?850-nm LED. The burn wound model was performed using a 100 °C copper plate, with 10 s of contact in the skin. The irradiations started 24 h after the lesion and were performed daily for 7 days. The burn wound groups showed an increase in the superoxide production, dichlorofluorescein, nitrites, and high protein oxidative damage. The activities of glutathione peroxidase and catalase were also increased, and a significant reduction in glutathione levels was observed compared to the control group. However, treatments with 660-nm LPL and 850-nm LED promoted protection against to oxidative stress, and similar results were also observed in the IL-6 and pERK1/2 expression. Taken together, these results suggest that LPL 660 nm and LED 850 nm appear reduced in the inflammatory response and oxidative stress parameters, thus decreasing dermal necrosis and increasing granulation tissue formation, in fact accelerating the repair of burn wounds.     

Platelet-Rich Plasma (PRP) Promotes Fetal Mesenchymal Stem/Stromal Cell Migration and Wound Healing Process

Numerous studies have shown the presence of high levels of growth factors during the process of healing. Growth factors act by binding to the cell surface receptors and contribute to the subsequent activation of signal transduction mechanisms. Wound healing requires a complex of biological and molecular events that includes attraction and proliferation of different type of cells to the wound site, differentiation and angiogenesis. More specifically, migration of various cell types, such as endothelial cells and their precursors, mesenchymal stem/stromal cells (MSCs) or skin fibroblasts (DFs) plays an important role in the healing process. In recent years, the application of platelet rich plasma (PRP) to surgical wounds and skin ulcerations is becoming more frequent, as it is believed to accelerate the healing process. The local enrichment of growth factors at the wound after PRP application causes a stimulation of tissue regeneration. Herein, we studied: (i) the effect of autologous PRP in skin ulcers of patients of different aetiology, (ii) the proteomic profile of PRP, (iii) the migration potential of amniotic fluid MSCs and DFs in the presence of PRP extract in vitro, (iv) the use of the PRP extract as a substitute for serum in cultivating AF-MSCs. Considering its easy access, PRP may provide a valuable tool in multiple therapeutic approaches.