Electrical stimulation as an adjunctive treatment of painful and sensory diabetic neuropathy

Peripheral Nerve Stimulation for Neuropathic Pain Management: A Narrative Review

This narrative review examines the therapeutic efficacy of peripheral nerve stimulation (PNS) in the treatment of neuropathic pain (NP), a type of pain arising from lesions or diseases of the somatosensory system with a global prevalence ranging from 6.90% to 10.00%. Traditional pharmacological interventions often fall short for many persons, highlighting the need for alternative treatments such as PNS, which has demonstrated significant promise with minimal side effects. The review summarizes the effectiveness of PNS in various NP conditions, including trigeminal neuralgia and postherpetic neuralgia, and underscores the need for further research to refine treatment approaches. The mechanism of PNS is discussed, involving the activation of non-nociceptive Aβ fibers and modulation of neurotransmitters, and offering pain relief through both peripheral and central pathways. Despite the proven efficacy of PNS, challenges remain, including the need for randomized controlled trials and the optimization of stimulation parameters. The review concludes that PNS is a promising treatment modality for NP, warranting additional high-quality trials to solidify its role in clinical practice.

Thin-film implants for bioelectronic medicine

This article is based on the MRS Mid-Career Researcher Award "for outstanding contributions to the fundamentals and development of organic electronic materials and their application in biology and medicine" presentation given by George G. Malliaras, University of Cambridge, at the 2023 MRS Spring Meeting in San Francisco, Calif.Bioelectronic medicine offers a revolutionary approach to treating disease by stimulating the body with electricity. While current devices show safety and efficacy, limitations, including bulkiness, invasiveness, and scalability, hinder their wider application. Thin-film implants promise to overcome these limitations. Made using microfabrication technologies, these implants conform better to neural tissues, reduce tissue damage and foreign body response, and provide high-density, multimodal interfaces with the body. This article explores how thin-film implants using organic materials and novel designs may contribute to disease management, intraoperative monitoring, and brain mapping applications. Additionally, the technical challenges to be addressed for this technology to succeed are discussed.

Graphical abstract

Adjunctive benefits of low-frequency transcutaneous electrical nerve stimulation for obesity frequent chronic conditions: a systematic review

Background

Obesity is widely recognized for its role in predisposing individuals to a spectrum of chronic health conditions. Emerging preliminary evidence points to the potential benefits of low-frequency transcutaneous electrical nerve stimulation (Lo-TENS) in enhancing various health outcomes among those with obesity and associated disorders.

Objective

This systematic review was designed to assess the effectiveness of Lo-TENS for managing obesity and its related chronic diseases.

Methods

For this systematic review, we included randomized controlled trials that evaluated the impact of Lo-TENS on individuals with obesity and its associated chronic diseases.

Results

Eight trials encompassing 671 participants and spanning three unique populations: essential hypertension (EH), type 2 diabetes mellitus (T2DM), and obesity were deemed eligible for inclusion in this review. Compared to baseline measurements, Lo-TENS demonstrated a tendency to positively affect blood pressure in individuals with EH and metabolic parameters in those with T2DM. Nonetheless, the efficacy of Lo-TENS in treating obesity is not yet clear when contrasted with a no-intervention control group. When compared with other intervention modalities, three of the trials reported less favorable results.

Conclusions

Although Lo-TENS did not consistently surpass other treatments or yield substantial improvements, it generally provided greater benefits than the majority of placebo controls. This suggests that Lo-TENS could potentially serve as a beneficial adjunctive therapy in the management of obesity and its associated conditions. However, given the limited number of trials assessed, the elevated risk of bias within these studies, and the scarce evidence currently available, it is too early to reach definitive conclusions. Caution should be exercised when interpreting the current findings. There is an imperative for further high-quality research to thoroughly investigate and substantiate the efficacy of Lo-TENS in relation to obesity and its related disorders.

Efficacy of electro-acupuncture versus sham acupuncture for diabetic peripheral neuropathy: study protocol for a three-armed randomised controlled trial

INTRODUCTION

Specific treatment for diabetic peripheral neuropathy (DPN) is still lacking, and acupuncture may relieve the symptoms. We intend to investigate the efficacy and safety of electro-acupuncture (EA) in alleviating symptoms associated with DPN in diabetes.

METHODS AND ANALYSIS

This multicentre, three-armed, participant- and assessor-blind, randomised, sham-controlled trial will recruit 240 eligible participants from four hospitals in China and will randomly assign (1:1:1) them to EA, sham acupuncture (SA) or usual care (UC) group. Participants in the EA and SA groups willl receive either 24-session EA or SA treatment over 8 weeks, followed by an 8-week follow-up period, while participants in the UC group will be followed up for 16 weeks. The primary outcome of this trial is the change in DPN symptoms from baseline to week 8, as rated by using the Total Symptom Score. The scale assesses four symptoms: pain, burning, paraesthesia and numbness, by evaluating the frequency and severity of each. All results will be analysed with the intention-to-treat population.

ETHICS AND DISSEMINATION

The protocol has been approved by the Ethics Committee of the Beijing University of Chinese Medicine (Identifier: 2022BZYLL0509). Every participant will be informed of detailed information about the study before signing informed consent. The results of this trial will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2200061408.

Update on Treating Painful Diabetic Peripheral Neuropathy: A Review of Current US Guidelines with a Focus on the Most Recently Approved Management Options

Painful diabetic peripheral neuropathy (DPN) is a highly prevalent and disabling complication of diabetes that is often misdiagnosed and undertreated. The management of painful DPN involves treating its underlying cause via lifestyle modifications and intensive glucose control, targeting its pathogenesis, and providing symptomatic pain relief, thereby improving patient function and health-related quality of life. Four pharmacologic options are currently approved by the US Food and Drug Administration (FDA) to treat painful DPN. These include three oral medications (duloxetine, pregabalin, and tapentadol extended release) and one topical agent (capsaicin 8% topical system). More recently, the FDA approved several spinal cord stimulation (SCS) devices to treat refractory painful DPN. Although not FDA-approved specifically to treat painful DPN, tricyclic antidepressants, serotonin/norepinephrine reuptake inhibitors, gabapentinoids, and sodium channel blockers are common first-line oral options in clinical practice. Other strategies may be used as part of individualized comprehensive pain management plans. This article provides an overview of the most recent US guidelines for managing painful DPN, with a focus on the two most recently approved treatment options (SCS and capsaicin 8% topical system), as well as evidence for using FDA-approved and guideline-supported drugs and devices. Also discussed are unmet needs for this patient population, and evidence for potential future treatments for painful DPN, including drugs with novel mechanisms of action, electrical stimulation devices, and nutraceuticals.

Intradialytic plantar electrical nerve stimulation to improve mobility and plantar sensation among adults with diabetes undergoing hemodialysis: a randomized double-blind trial

BACKGROUND

Impaired mobility is a debilitating consequence of hemodialysis. We examined the efficacy of intradialytic-plantar-electrical-nerve-stimulation (iPENS) to promote mobility among diabetes patients undergoing hemodialysis..

METHODS

Adults with diabetes undergoing hemodialysis received either 1-h active iPENS, (Intervention-Group) or non-functional iPENS (Control-Group) during routine hemodialysis for 12 weeks (3 sessions/week). Participants and care-providers were blinded. Mobility (assessed using a validated pendant-sensor) and neuropathy (quantified by vibration-perception-threshold test) outcomes were assessed at baseline and 12 weeks.

RESULTS

Among 77 enrolled subjects (56.2 ± 2.6 years old), 39 were randomly assigned to the intervention group, while 38 were assigned to the control group. No study-related adverse events and dropouts were reported in the intervention group. Compared to the control group, significant improvements with medium to large effect sizes were observed in the intervention group at 12 weeks for mobility-performance metrics, including active-behavior, sedentary-behavior, daily step counts, and sit-to-stand duration variability (p < 0.05), Cohen's d effect size (d = 0.63-0.84). The magnitude of improvement in active-behavior was correlated with improvement in the vibration-perception-threshold test in the intervention group (r = - 0.33, p = 0.048). A subgroup with severe-neuropathy (vibration-perception-threshold > 25 V) showed a significant reduction in plantar numbness at 12 weeks compared to baseline (p = 0.03, d = 1.1).

CONCLUSIONS

This study supports feasibility, acceptability, and effectiveness of iPENS to improve mobility and potentially reduce plantar numbness in people with diabetes undergoing hemodialysis. Considering that exercise programs are not widely used in hemodialysis clinical practice, iPENS may serve as a practical, alternative solution to reduce hemodialysis-acquired weakness and promote mobility.

Home-Based Electrical Stimulation to Accelerate Wound Healing-A Double-Blinded Randomized Control Trial

BACKGROUND

Electrical stimulation (E-Stim) may offer a unique adjunctive treatment to heal complicated diabetic foot ulcers (DFU). Our primary goal is to examine the effectiveness of daily home-based E-Stim therapy to speed-up wound healing.

METHODS

Patients with chronic DFUs and mild to severe peripheral arterial disease (PAD) were recruited and randomized to either control (CG) or intervention (IG) groups. The IG received 1-hour home-based E-Stim therapy on daily basis for 4 weeks (4W). E-Stim was delivered through electrical pads placed above the ankle joint using a bio-electric stimulation technology (BEST^®) platform (Tennant Biomodulator^® PRO). The CG was provided with an identical but non-functional device for the same period. The primary outcome included wound area reduction at 4W from baseline (BL).

RESULTS

Thirty-eight patients were recruited and 5 were removed due to non-compliance or infection, leaving 33 participants (IG, n = 16; CG, n =17). At 4W, the IG showed a significant wound area reduction of 22% (BL: 7.4 ± 8.5 cm² vs 4W: 5.8 ± 8.0 cm², P = 0.002). Average of wound area was unchanged in the CG (P = 0.982). The self-report adherence to daily home-therapy was 93.9%.

CONCLUSIONS

Daily home-based E-Stim provides early results on the feasibility, acceptability, and effectiveness of E-Stim as an adjunctive therapy to speed up wound healings in patients with chronic DFU and mild to severe PAD.

[Diabetic neuropathy and diabetic foot syndrome (update 2023)]

These are the guidelines for diagnosis and treatment of diabetic neuropathy and diabetic foot.The position statement summarizes characteristic clinical symptoms and techniques for diagnostic assessment of diabetic neuropathy, including the complex situation of the diabetic foot syndrome. Recommendations for the therapeutic management of diabetic neuropathy, especially for the control of pain in sensorimotor neuropathy, are provided. The needs to prevent and treat diabetic foot syndrome are summarized.

Recent updates in the treatment of diabetic polyneuropathy

Distal symmetric diabetic peripheral polyneuropathy (DPN) is the most common form of neuropathy in the world, affecting 30 to 50% of diabetic individuals and resulting in significant morbidity and socioeconomic costs. This review summarizes updates in the diagnosis and management of DPN. Recently updated clinical criteria facilitate bedside diagnosis, and a number of new technologies are being explored for diagnostic confirmation in specific settings and for use as surrogate measures in clinical trials. Evolving literature indicates that distinct but overlapping mechanisms underlie neuropathy in type 1 versus type 2 diabetes, and there is a growing focus on the role of metabolic factors in the development and progression of DPN. Exercise-based lifestyle interventions have shown therapeutic promise. A variety of potential disease-modifying and symptomatic therapies are in development. Innovations in clinical trial design include the incorporation of detailed pain phenotyping and biomarkers for central sensitization.

Research progress in membrane fusion-based hybrid exosomes for drug delivery systems

Liposomes are the earliest and most widely used nanoparticles for targeted drug delivery. Exosomes are nanosized membrane-bound particles and important mediators of intercellular communication. Combining liposomes and exosomes using various membrane fusion methods gives rise to a novel potential drug delivery system called membrane fusion-based hybrid exosomes (MFHE). These novel MFHEs not only exhibit potential advantageous features, such as high drug loading rate and targeted cellular uptake via surface modification, but are also endowed with high biocompatibility and low immunogenicity. Here, we provide an overview of MFHEs’ various preparation methods, characterization strategies, and their applications for disease treatment and scientific research.

Current Strategies for the Management of Painful Diabetic Neuropathy

The development of painful diabetic neuropathy (PDN) is a common complication of chronic diabetes that can be associated with significant disability and healthcare costs. Prompt symptom identification and aggressive glycemic control is essential in controlling the development of neuropathic complications; however, adequate pain relief remains challenging and there are considerable unmet needs in this patient population. Although guidelines have been established regarding the pharmacological management of PDN, pain control is inadequate or refractory in a high proportion of patients. Pharmacotherapy with anticonvulsants (pregabalin, gabapentin) and antidepressants (duloxetine) are common first-line agents. The use of oral opioids is associated with considerable morbidity and mortality and can also lead to opioid-induced hyperalgesia. Their use is therefore discouraged. There is an emerging role for neuromodulation treatment modalities including intrathecal drug delivery, spinal cord stimulation, and dorsal root ganglion stimulation. Furthermore, consideration of holistic alternative therapies such as yoga and acupuncture may augment a multidisciplinary treatment approach. This aim of this review is to focus on the current management strategies for the treatment of PDN, with a discussion of treatment rationale and practical considerations for their implementation.

Recent updates in the treatment of diabetic polyneuropathy

Distal symmetric diabetic peripheral polyneuropathy (DPN) is the most common form of neuropathy in the world, affecting 30 to 50% of diabetic individuals and resulting in significant morbidity and socioeconomic costs. This review summarizes updates in the diagnosis and management of DPN. Recently updated clinical criteria facilitate bedside diagnosis, and a number of new technologies are being explored for diagnostic confirmation in specific settings and for use as surrogate measures in clinical trials. Evolving literature indicates that distinct but overlapping mechanisms underlie neuropathy in type 1 versus type 2 diabetes, and there is a growing focus on the role of metabolic factors in the development and progression of DPN. Exercise-based lifestyle interventions have shown therapeutic promise. A variety of potential disease-modifying and symptomatic therapies are in development. Innovations in clinical trial design include the incorporation of detailed pain phenotyping and biomarkers for central sensitization.

Effectiveness of Lower-Extremity Electrical Stimulation to Improve Skin Perfusion

BACKGROUND

Although numerous studies suggest the benefit of electrical stimulation (E-Stim) therapy to accelerate wound healing, the underlying mechanism of action is still debated. In this pilot study, we examined the potential effectiveness of lower-extremity E-Stim therapy to improve tissue perfusion in patients with diabetic foot ulcers.

METHODS

Thirty-eight patients with diabetic foot ulcers underwent 60 min of active E-Stim therapy on acupuncture points above the level of the ankle joint using a bioelectric stimulation technology platform. Perfusion changes in response to E-Stim were assessed by measuring skin perfusion pressure (SPP) at baseline and during 30 and 60 min of therapy; retention was assessed 10 min after therapy. Tissue oxygen saturation (SatO2) was measured using a noninvasive near-infrared camera.

RESULTS

Skin perfusion pressure increased in response to E-Stim therapy (P = .02), with maximum improvement observed at 60 min (11%; P = .007) compared with baseline; SPP reduced 10 min after therapy but remained higher than baseline (9%; P = .1). Magnitude of improvement at 60 min was negatively correlated with baseline SPP values (r = -0.45; P = .01), suggesting that those with lower perfusion could benefit more from E-Stim therapy. Similar trends were observed for SatO2, with statistically significant improvement for a subsample (n = 16) with moderate-to-severe peripheral artery disease.

CONCLUSIONS

This study provides early results on the feasibility and effectiveness of E-Stim therapy to improve skin perfusion and SatO2. The magnitude of benefit is higher in those with poorer skin perfusion. Also, the effects of E-Stim could be washed out after stopping therapy, and regular daily application might be required for effective benefit in wound healing.

Treatment of painful diabetic neuropathy

Painful diabetic neuropathy is observed in almost half of patients with diabetes mellitus (DM) and is associated with a decrease in the quality of life, emotional disorders, sleep disorders. The achievement and maintenance of the normal level of glucose in the blood is the basis for the prevention and treatment of DM, but this often does not allow the patient from pain and other clinical manifestations of neuropathy. Drug diabetic neuropathy therapy methods are discussed, the results of randomized placebo controlled studies on the efficiency and side effects of various drugs are analyzed. It is noted that pregabalin and gabapenitin, as antidepressants duloxetin, venlafaxin and amitriptyline, are most effective as anti-epileptic agents. In our country, with painful diabetic neuropathy, the preparations of a-lipoic acid are widely used. Analyzed data on efficacy and complications of the use of transcutaneus electrical nerves stimulation and spinal cord stimulation with pain diabetic neuropathy refractory to drug therapy. It is noted that many patients with pain diabetic neuropathy have combined diseases, detection and effective treatment of which can lead to an improvement in the state of patients and reduce the manifestations of neuropathy.

Management of diabetic neuropathy

Diabetic neuropathy is a neurodegenerative disorder that may alter both the somatic and autonomic peripheral nervous systems in the context of diabetes mellitus (DM). It is a prevalent and burdensome chronic complication of DM, that requires timely management. Optimized glycemic control (mainly for type 1 DM), multifactorial intervention (mainly for type 2 DM), with lifestyle intervention/physical exercise, and weight loss represent the basis of management for diabetic distal symmetrical polyneuropathy, and should be implemented early in the disease course. Despite better understanding of the pathogenetic mechanisms of diabetic peripheral neuropathy, there is still a stringent need for more pathogenetic-based agents that would significantly modify the natural history of the disease. The paper reviews the available drugs and current recommendations for the management of distal symmetrical polyneuropathy, including pain management, and for diabetic autonomic neuropathy. Evaluation of drug combinations that would perhaps be more efficient in slowing the progression of the disease or even reversing it, and that would provide a better pain management is still needed.

Interventional Clinical Trials on Diabetic Peripheral Neuropathy: A Retrospective Analysis

AIMS/INTRODUCTION

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes. At present, there is no comprehensive summary of the clinical trials related to DPN. In this article, we summarized the basic characteristics of the interventional clinical trials pertaining to DPN to determine the current status of research in this field and the existing issues.

MATERIALS AND METHODS

We searched the World Health Organization International Clinical Trial Registration Platform (ICTRP), PubMed and Web of Science for clinical trials from 2005 to April 2021 and extracted 149 registered and 459 published clinical trials on DPN. We summarized the characteristics of the clinical trials, including the source registration, recruitment status, stage, age group, allocation method, intervention, end point classification, funding source, and treatment.

RESULTS

After excluding noninterventional and nontreatment trials, 149 registered clinical trials out of 292 records from 12 registration centers and 459 published articles were included in this study. Among the registered trials, 43% had been completed, and 34.4% had been published in peer-reviewed journals. Among these trials, more than half used random allocation and blinded placebo-controlled methodologies. A total of 40.3% of the trials were multicenter studies, 63.8% of the treatments were drug therapies, and the endpoint classifications of 49% were efficacy and safety. Of the 459 published interventional clinical trials on DPN, 69.7% of the trials used drug treatments; more than half were randomized, double-blind, placebo-controlled clinical trials; 94.1% had positive outcomes; 46.4% had a target size of 50; and 22.9% were multicenter.

CONCLUSION

This paper systematically summarizes the current status of interventional trials on DPN registered in the ICTRP and published clinical trials and provides a reference for the development of high-quality intervention strategies for DPN in the future.

Transplantation of engineered exosomes derived from bone marrow mesenchymal stromal cells ameliorate diabetic peripheral neuropathy under electrical stimulation

Diabetic peripheral neuropathy (DPN) is a long-term complication associated with nerve dysfunction and uncontrolled hyperglycemia. In spite of new drug discoveries, development of effective therapy is much needed to cure DPN. Here, we have developed a combinatorial approach to provide biochemical and electrical cues, considered to be important for nerve regeneration. Exosomes derived from bone marrow mesenchymal stromal cells (BMSCs) were fused with polypyrrole nanoparticles (PpyNps) containing liposomes to deliver both the cues in a single delivery vehicle. We developed DPN rat model and injected intramuscularly the fused exosomal system to understand its long-term therapeutic effect. We found that the fused system along with electrical stimulation normalized the nerve conduction velocity (57.60 ± 0.45 m/s) and compound muscle action potential (16.96 ± 0.73 mV) similar to healthy control (58.53 ± 1.10 m/s; 18.19 ± 1.45 mV). Gastrocnemius muscle morphology, muscle mass, and integrity were recovered after treatment. Interestingly, we also observed paracrine effect of delivered exosomes in controlling hyperglycemia and loss in body weight and also showed attenuation of damage to the tissues such as the pancreas, kidney, and liver. This work provides a promising effective treatment and also contribute cutting edge therapeutic approach for the treatment of DPN.

Treatment of Painful Diabetic Neuropathy-A Narrative Review of Pharmacological and Interventional Approaches

Painful diabetic neuropathy (PDN) is a common complication of diabetes mellitus that is associated with a significant decline in quality of life. Like other painful neuropathic conditions, PDN is difficult to manage clinically, and a variety of pharmacological and non-pharmacological options are available for this condition. Recommended pharmacotherapies include anticonvulsive agents, antidepressant drugs, and topical capsaicin; and tapentadol, which combines opioid agonism and norepinephrine reuptake inhibition, has also recently been approved for use. Additionally, several neuromodulation therapies have been successfully used for pain relief in PDN, including intrathecal therapy, transcutaneous electrical nerve stimulation (TENS), and spinal cord stimulation (SCS). Recently, 10 kHz SCS has been shown to provide clinically meaningful pain relief for patients refractory to conventional medical management, with a subset of patients demonstrating improvement in neurological function. This literature review is intended to discuss the dosage and prospective data associated with pain management therapies for PDN.

Considerations for single- versus multiple-drug pharmacotherapy in the management of painful diabetic neuropathy

INTRODUCTION

The efficacy of monotherapy to reduce pain from diabetic peripheral neuropathy (DPN) is frequently not satisfactory and guidelines do not provide unanimous treatment options. In this context, multiple drug pharmacotherapy may provide benefit.

AREAS COVERED

The aim of the present review is to describe the clinical trials addressing the pharmacotherapy of painful DPN. Studies discussing efficacy and tolerability of pharmacological agents that were assessed in monotherapy and in combination treatment are reported and discussed.

EXPERT OPINION

Several clinical trials have reported benefit of multiple-drug pharmacotherapy. Nevertheless, untoward effects of combination treatment are of concern. Importantly, some trials were restricted to comparison with placebo and other compared only with active comparator(s). Only limited clinical trials assessed selected cohorts of individuals experiencing different stages of painful DPN. Despite current limitations, some evidence of studies implicating a comparison to all active comparators points to safety and effectiveness of the combination of oxycodone with pregabalin and that of pregabalin with the 5% lidocaine plaster but future, clear-cut studies are required to drive evidence-based decisions in the clinical setting.

Diabetic Peripheral Neuropathy: Diagnosis and Treatment

BACKGROUND

Diabetic peripheral neuropathy (DPN) is traditionally divided into large and small fibre neuropathy (SFN). Damage to the large fibres can be detected using nerve conduction studies (NCS) and often results in a significant reduction in sensitivity and loss of protective sensation, while damage to the small fibres is hard to reliably detect and can be either asymptomatic, associated with insensitivity to noxious stimuli, or often manifests itself as intractable neuropathic pain.

OBJECTIVE

To describe the recent advances in both detection, grading, and treatment of DPN as well as the accompanying neuropathic pain.

METHODS

A review of relevant, peer-reviewed, English literature from MEDLINE, EMBASE and Cochrane Library between January 1st 1967 and January 1st 2020 was used.

RESULTS

We identified more than three hundred studies on methods for detecting and grading DPN, and more than eighty randomised-controlled trials for treating painful diabetic neuropathy.

CONCLUSION

NCS remains the method of choice for detecting LFN in people with diabetes, while a gold standard for the detection of SFN is yet to be internationally accepted. In the recent years, several methods with huge potential for detecting and grading this condition have become available including skin biopsies and corneal confocal microscopy, which in the future could represent reliable endpoints for clinical studies. While several newer methods for detecting SFN have been developed, no new drugs have been accepted for treating neuropathic pain in people with diabetes. Tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors and anticonvulsants remain first line treatment, while newer agents targeting the proposed pathophysiology of DPN are being developed.

Efficacy of Electrical Stimulation on Nerve Fiber Growth in Small Fiber Neuropathy

OBJECTIVES

To define whether electrical nerve stimulation (ENS) therapy would promote intraepidermal nerve growth and nerve regeneration in patients with small fiber neuropathy (SFN).

METHODS

This was a prospective study conducted on 8 subjects with previously diagnosed SFN. Nerve conduction testing, punch biopsies, and clinical examinations with a calculation of revised total neuropathy score were conducted on subjects before beginning ENS therapy and at 30 and 60 days after the start of ENS therapy.

RESULTS

Clinical examination findings and intraepidermal nerve fiber density measurements on day 30 and day 60 did not show statistically significant changes in the treated group compared with the untreated group.

CONCLUSIONS

Despite the success of previous animal studies, no meaningful nerve growth and regeneration in SFN was demonstrated with ENS therapy in this study. Studies of larger subject larger populations with longer duration of ENS treatment are warranted to confirm our findings.

Diabetic Polyneuropathy - Advances in Diagnosis and Intervention Strategies

Over half of people with diabetes mellitus develop diabetic polyneuropathy (DPN), which is a major cause of reduced quality of life due to disabling neuropathic pain, sensory loss, gait instability, fall-related injury, and foot ulceration and amputation. The latter represents a major health and economic burden, with lower limb amputation rates related to diabetes increasing in the UK. There is a need for early diagnosis of DPN so that early management strategies may be instigated, such as achieving tight glucose control and management of cardiovascular risk factors, in an attempt to slow its progression. To this end, a one-stop microvascular assessment involving a combined eye, foot and renal screening clinic has proven feasible in the UK. Unfortunately, there are currently no approved disease-modifying therapies for DPN. Some disease-modifying agents have demonstrated efficacy, but further large trials using appropriate clinical endpoints are required before these treatments can be routinely recommended. There has been emerging evidence highlighting a reduction in vitamin D levels in cases of painful DPN and the potential for vitamin D supplementation in deficient individuals to improve neuropathic pain; however, this needs to be proved in randomised clinical trials. The use of established agents for neuropathic pain in DPN is limited by poor efficacy and adverse effects, but patient stratification using methods such as pain phenotyping are being tested to determine whether this improves the outcomes of such agents in clinical studies. In addition, innovative approaches such as the topical 8% capsaicin patch, new methods of electrical stimulation and novel therapeutic targets such as NaV1.7 offer promise for the future. This article aims to discuss the challenges of diagnosing and managing DPN and to review current and emerging lifestyle interventions and therapeutic options.

Comparison of Efficacy of Nortriptyline Versus Transcutaneous Electrical Nerve Stimulation on Painful Peripheral Neuropathy in Patients with Diabetes

Background and aims: Diabetic peripheral neuropathic pain (DPNP) is one of the most common complications of diabetes and is difficult to treat. Existing treatments are often inadequate at controlling pain and limited by side-effects and drug tolerance. This study assessed the efficacy of nortriptyline versus Transcutaneous Electrical Nerve Stimulation (TENS) in patients with DPNP.

Material and method: This is a randomized clinical trial study conducted on 39 patients with DPNP referring to Golestan Hospital in Ahvaz in 2017. Patients were randomly treated with TENS (18 sessions, each session 30 minutes; n=20) or nortriptyline (25 to 75 mg, once daily; n=19) for 6 weeks. Patients were evaluated for side effects and pain relief using visual analog scale (VAS).

Results: There was a significant improvement in pain with both treatments compared with baseline (p˂0.001). The patients in nortriptyline group experienced more pain relief (7.21±1.51 to 0.84±1.34) than the TENS group (7.6±1.47 to 2.75 ±2.43) (P=0.001). The 50% pain relief was observed in 14 patients (73%) in nortriptyline group, 6 patients (30%) in TENS group. Moreover, the side effects were seen in 15% of TENS and 55% of patients in nortriptyline groups (P=0.019).

Conclusion: Both TENS and nortriptyline were effective and safe in the management of DPNP. But nortriptyline showed a better performance on pain relief.

New Perspective in Diabetic Neuropathy: From the Periphery to the Brain, a Call for Early Detection, and Precision Medicine

Diabetic peripheral neuropathy (DPN) is a common chronic complication of diabetes mellitus. It leads to distressing and expensive clinical sequelae such as foot ulceration, leg amputation, and neuropathic pain (painful-DPN). Unfortunately, DPN is often diagnosed late when irreversible nerve injury has occurred and its first presentation may be with a diabetic foot ulcer. Several novel diagnostic techniques are available which may supplement clinical assessment and aid the early detection of DPN. Moreover, treatments for DPN and painful-DPN are limited. Only tight glucose control in type 1 diabetes has robust evidence in reducing the risk of developing DPN. However, neither glucose control nor pathogenetic treatments are effective in painful-DPN and symptomatic treatments are often inadequate. It has recently been hypothesized that using various patient characteristics it may be possible to stratify individuals and assign them targeted therapies to produce better pain relief. We review the diagnostic techniques which may aid the early detection of DPN in the clinical and research environment, and recent advances in precision medicine techniques for the treatment of painful-DPN.

Efficacy and safety of duloxetine and Pregabalin in Iranian patients with diabetic peripheral neuropathic pain: a double-blind, randomized clinical trial

Purpose

Diabetic peripheral neuropathic pain (DPNP) is one of the most sufferings, disabling, and dominant complications of diabetes. Duloxetine (DLX) and Pregabalin (PGB) are among first-line therapy and the most prescribed drugs for DPNP relief. The effectiveness-risk profile of drugs may differ from region to region due to variations in genetic and health situation of populations. This study aims to evaluate the efficacy and safety of DLX and PGB in a sample of Iranian population with DPNP.

Methods

A double-blind, randomized clinical trial was conducted on 180 type-2 diabetic patients with DPNP≥40 mm according to Visual Analogue Scale (VAS), with other eligibility criteria throughout twelve weeks. We divided the patients randomly into two equal groups: DLX and PGB. Each patient received ten days placebo as a washout period, then blind capsules of DLX (group 1) or PGB (group 2). We assessed the efficacy and safety of drugs by VAS and recorded the Adverse Drug Reactions (ADRs) during the study.

Results

In the DLX group, sixty-six and the PGB group, seventy-eight patients completed the study. The intensity of patients’ pain was improved by both drugs significantly (p˂0.001), but there was no significant difference between the two groups. Average daily doses of DLX and PGB were 42.5 and 235.5 mg, respectively. In the DLX group, 74% of patients and the PGB group, 37% reported ADRs. The discontinuation rates due to ADRs were 19% and 7% correspondingly.

Conclusion

We found that in Iranian patients, the mean effective doses of these drugs are different in comparison with several other studies. Surprisingly intolerance and discontinuation of DLX in our patients were attributed to mild and severe Serotonin Syndrome, which had not much occurred in other studies. Accordingly, despite the same efficacy, PGB was better tolerated than DLX in our patients. Thus we would recommend PGB for DPNP treatment in Iranian patients.

Efficacy of Biophysical Energies on Healing of Diabetic Skin Wounds in Cell Studies and Animal Experimental Models: A Systematic Review

We have systematically assessed published cell studies and animal experimental reports on the efficacy of selected biophysical energies (BPEs) in the treatment of diabetic foot ulcers. These BPEs include electrical stimulation (ES), pulsed electromagnetic field (PEMF), extracorporeal shockwave (ECSW), photo energies and ultrasound (US). Databases searched included CINAHL, MEDLINE and PubMed from 1966 to 2018. Studies reviewed include animal and cell studies on treatment with BPEs compared with sham, control or other BPEs. Information regarding the objective measures of tissue healing and data was extracted. Eighty-two studies were eventually selected for the critical appraisal: five on PEMF, four each on ES and ECSW, sixty-six for photo energies, and three about US. Based on the percentage of original wound size affected by the BPEs, both PEMF and low-level laser therapy (LLL) demonstrated a significant clinical benefit compared to the control or sham treatment, whereas the effect of US did not reveal a significance. Our results indicate potential benefits of selected BPEs in diabetic wound management. However, due to the heterogeneity of the current clinical trials, comprehensive studies using well-designed trials are warranted to confirm the results.

Electrical peripheral nerve stimulation relieves bone cancer pain by inducing Arc protein expression in the spinal cord dorsal horn

Objective

The analgesic effect on chronic pain of peripheral nerve stimulation (PNS) has been proven, but its underlying mechanism remains unknown. Therefore, this study aimed to assess the analgesic effect of PNS on bone cancer pain in a rat model and to explore the underlying mechanism.

Materials and methods

PNS on sciatic nerves with bipolar electrode was performed in both naïve and bone cancer pain model rats. Then, the protein levels of activity-regulated cytoskeleton-associated protein (Arc), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid–type glutamate receptor 1 (GluA1), and phosphate N-methyl-d-aspartic acid-type glutamate receptor subunit 2B (pGluNR2B) in spinal cord were evaluated by immunohistochemistry and Western blotting. Thermal paw withdraw latency and mechanical paw withdraw threshold were used to estimate the analgesic effect of PNS on bone cancer pain. Intrathecal administration of Arc shRNA was used to inhibit Arc expression in the spinal cord.

Results

PNS at 60 and 120 Hz for 20 min overtly induced Arc expression in the spinal cord, increased thermal pain thresholds in naïve rats, and relieved bone cancer pain; meanwhile, 10 Hz PNS did not achieve those results. In addition, PNS at 60 and 120 Hz also reduced the expression of GluA1, but not pGluNR2B, in the spinal cord. Finally, the anti-nociceptive effect and GluA1 downregulation induced by PNS were inhibited by intrathecal administration of Arc shRNA.

Conclusion

PNS (60 Hz, 0.3 mA) can relieve bone-cancer-induced allodynia and hyperalgesia by upregulating Arc protein expression and then by decreasing GluA1 transcription in the spinal cord dorsal horn.

Use of Spinal Cord Stimulation in Elderly Patients with Multi-Factorial Chronic Lumbar and Non-Radicular Lower Extremity Pain

Spinal cord stimulation (SCS) is an effective treatment for chronic back and limb pain. The criteria for use of SCS for specific problems such as failed back surgery syndrome (FBSS), peripheral neuropathic pain and residual pain after joint replacement is well established. With an aging population, there are more patients presenting with a combination of various multi-factorial chronic pain problems rather than from a single clear cause. It is not uncommon to see patients with chronic back pain years after spine surgery with new additional pain in the area of joint replacement or due to peripheral neuropathy. In most of these patients, one area is the primary cause of their pain, while the other more secondary. Multiple chronic problems complicate the pain management of the primary cause and also can diminish the effect of SCS that only targets the primary problem. The primary and secondary causes of pain were ranked by the patient including the duration of their chronic pain for each area. This helped establish criteria for use of SCS in these complex pain patients. The patients were evaluated initially with an epidural stimulator trial and if they obtained 50% or greater pain relief to the primary pain generating area, permanent implantation of one or more arrays of spinal cord electrodes was performed but planned to cover also the secondary pain areas. Post-implant follow-up evaluation at one, three and six months included measurement of visual analog scale (VAS), use of pain medication and degree of functional activity and behavior. This report looks at the effectiveness of using multiple overlapping electrodes for SCS in patients with multi-factorial chronic pain.

Measurement reliability of current perception threshold and pain threshold in parallel with blood sampling

The irritation and pain associated with oral blood sampling necessary to monitor glycemic control can alter oral sensation, but no studies have measured the reliability of oral sensation testing when performed concurrently with blood sampling. The primary and secondary aims of this study were to verify the measurement reliability of current perception threshold (CPT) and pain threshold (PT) tests performed before and after blood sampling and to investigate the differences in CPTs/PTs obtained from the oral cavity, hand, and foot, respectively. CPT/PT measurements were obtained from the oral mucosa and the tips of fingers and toes of 18 volunteers (10 males and 8 females, average age = 26.3 years) using electrical stimulation at frequencies of 5, 250, and 2,000 Hz. Participants also provided blood samples by pricking their own index fingers with a small needle. All subjects completed the following 3 conditions at once-weekly intervals as follows: (a) sensory measurements followed by blood sampling (SB block); (b) blood sampling followed by sensory measurements (BS block); (c) sensory measurements without blood sampling (CO control block). Cronbach's α coefficients were over 0.78 for the SB, BS, and CO blocks, and are considered to be acceptable for assuring measurement reliability. The oral cavity had significantly lower CPT/PTs than both hands and feet, such that the threshold increased in the order oral cavity < hand < foot. CPT and PT measurements performed concurrently with blood sampling are both reliable and region specific, and for which the oral cavity is the most sensitive testing region.

Using Plantar Electrical Stimulation to Improve Postural Balance and Plantar Sensation Among Patients With Diabetic Peripheral Neuropathy: A Randomized Double Blinded Study

OBJECTIVE

People with diabetic peripheral neuropathy (DPN) often exhibit deteriorations in motor-performance mainly due to lack of plantar-sensation. The study explored effectiveness of plantar electrical-stimulation therapy to enhance motor-performance among people with DPN.

DESIGN AND METHODS

Using a double-blinded model, 28 volunteers with DPN (age: 57.8 ± 10.2 years) were recruited and randomized to either intervention (IG: n = 17) or control (CG: n = 11) group. Both groups received identical plantar-stimulation devices for six weeks of daily use at home; however, only the IG devices were set to deliver stimulation. Balance (ankle, hip, and center of mass [COM] sway) and gait (stride velocity [SV], stride time [ST], stride length [SL], and cadence) were measured using validated wearable sensors. Outcomes were assessed at baseline and at six-week. Clinical assessment including vascular as measured by ankle-brachial-index (ABI) and plantar-sensation as quantified by vibratory plantar threshold (VPT) were also measured at baseline and six weeks.

RESULTS

No difference were observed between groups for baseline characteristics ( P > .050). Posttherapy, ankle and COM sway with eyes open were significantly improved ( P < .05, Cohen's effect size d = 0.67-0.76) in the IG with no noticeable changes in CG. All gait parameters were significantly improved in the IG with highest effect size observed for cadence ( d = 1.35, P = .000). Results revealed improvement in VPT ( P = .004, d = 1.15) with significant correlation with stride velocity improvement ( r = .56, P = .037). ABI was improved in the IG in particulate among those with ABI>1.20 ( P = .041, d = 0.99) Conclusion: This study suggests that daily home use of plantar electrical-stimulation may be a practical means to enhance motor-performance and plantar-sensation in people with DPN.

Modulation of cell function by electric field: a high-resolution analysis

Regulation of cell function by a non-thermal, physiological-level electromagnetic field has potential for vascular tissue healing therapies and advancing hybrid bioelectronic technology. We have recently demonstrated that a physiological electric field (EF) applied wirelessly can regulate intracellular signalling and cell function in a frequency-dependent manner. However, the mechanism for such regulation is not well understood. Here, we present a systematic numerical study of a cell-field interaction following cell exposure to the external EF. We use a realistic experimental environment that also recapitulates the absence of a direct electric contact between the field-sourcing electrodes and the cells or the culture medium. We identify characteristic regimes and present their classification with respect to frequency, location, and the electrical properties of the model components. The results show a striking difference in the frequency dependence of EF penetration and cell response between cells suspended in an electrolyte and cells attached to a substrate. The EF structure in the cell is strongly inhomogeneous and is sensitive to the physical properties of the cell and its environment. These findings provide insight into the mechanisms for frequency-dependent cell responses to EF that regulate cell function, which may have important implications for EF-based therapies and biotechnology development.

Burning through the pain: treatments for diabetic neuropathy

The rise in the global burden of diabetes is spurring an increase in the prevalence of its complications. Diabetic peripheral neuropathy (DPN) is a common and devastating complication of diabetes, with multiple clinical manifestations. The most common is a symmetrical length-dependent dysfunction and damage of peripheral nerves. The management of DPN rests on three tenets: intensive glycaemic control, even though the evidence of benefit is questionable in people with type 2 diabetes; pathogenetic therapies; and symptomatic treatment. A number of pathogenetic treatments have been evaluated in phase III clinical trials, including α-lipoic acid (stems reactive oxygen species formation), benfotiamine (prevents vascular damage) and aldose-reductase inhibitors (reduce flux through the polyol pathway), protein kinase C inhibitors (prevent hyperglycaemia-induced activation of protein kinase C), nerve growth factors (stimulate nerve regeneration) and Actovegin® (improves tissue glucose and oxygen uptake). However, none have gained US Food and Drug Administration or European Medicines Agency (EMA) approval, questioning the validity of current trial designs and the endpoints deployed to define efficacy. For painful diabetic neuropathy, clinical guidelines recommend: atypical analgesics for pain relief, including duloxetine and amitriptyline; the γ-aminobutyric acid analogues gabapentin and pregabalin; opioids, including Tapentadol; and topical agents such as lidocaine and capsaicin. No single effective treatment exists for painful DPN, highlighting a growing need for studies to evaluate more potent and targeted drugs, as well as combinations. A number of novel potential candidates, including erythropoietin analogues and angiotensin II type 2 receptor anatagonists are currently being evaluated in phase II clinical trials.

Treating Diabetic Neuropathy: Present Strategies and Emerging Solutions

Diabetic peripheral neuropathies (DPN) are a heterogeneous group of disorders caused by neuronal dysfunction in patients with diabetes. They have differing clinical courses, distributions, fiber involvement (large or small), and pathophysiology. These complications are associated with increased morbidity, distress, and healthcare costs. Approximately 50% of patients with diabetes develop peripheral neuropathy, and the projected rise in the global burden of diabetes is spurring an increase in neuropathy. Distal symmetrical polyneuropathy (DSPN) with painful diabetic neuropathy, occurring in around 20% of diabetes patients, and diabetic autonomic neuropathy (DAN) are the most common manifestations of DPN. Optimal glucose control represents the only broadly accepted therapeutic option though evidence of its benefit in type 2 diabetes is unclear. A number of symptomatic treatments are recommended in clinical guidelines for the management of painful DPN, including antidepressants such as amitriptyline and duloxetine, the γ-aminobutyric acid analogues gabapentin and pregabalin, opioids, and topical agents such as capsaicin. However, monotherapy is frequently not effective in achieving complete resolution of pain in DPN. There is a growing need for head-to-head studies of different single-drug and combination pharmacotherapies. Due to the ubiquity of autonomic innervation in the body, DAN causes a plethora of symptoms and signs affecting cardiovascular, urogenital, gastrointestinal, pupillomotor, thermoregulatory, and sudomotor systems. The current treatment of DAN is largely symptomatic, and does not correct the underlying autonomic nerve deficit. A number of novel potential candidates, including erythropoietin analogues, angiotensin II receptor type 2 antagonists, and sodium channel blockers are currently being evaluated in phase II clinical trials.

Treatment of painful diabetic neuropathy

Painful diabetic neuropathy (PDN) is a debilitating consequence of diabetes that may be present in as many as one in five patients with diabetes. The objective assessment of PDN is difficult, making it challenging to diagnose and assess in both clinical practice and clinical trials. No single treatment exists to prevent or reverse neuropathic changes or to provide total pain relief. Treatment of PDN is based on three major approaches: intensive glycaemic control and risk factor management, treatments based on pathogenetic mechanisms, and symptomatic pain management. Clinical guidelines recommend pain relief in PDN through the use of antidepressants such as amitriptyline and duloxetine, the γ-aminobutyric acid analogues gabapentin and pregabalin, opioids and topical agents such as capsaicin. Of these medications, duloxetine and pregabalin were approved by the US Food and Drug Administration (FDA) in 2004 and tapentadol extended release was approved in 2012 for the treatment of PDN. Proposed pathogenetic treatments include α-lipoic acid (stems reactive oxygen species formation), benfotiamine (prevents vascular damage in diabetes) and aldose-reductase inhibitors (reduces flux through the polyol pathway). There is a growing need for studies to evaluate the most potent drugs or combinations for the management of PDN to maximize pain relief and improve quality of life. A number of agents are potential candidates for future use in PDN therapy, including Nav 1.7 antagonists, N-type calcium channel blockers, NGF antibodies and angiotensin II type 2 receptor antagonists.