Evidence-Based Treatment of Painful Diabetic Neuropathy: a Systematic Review

Diabetic peripheral neuropathy and neuromodulation techniques: a systematic review of progress and prospects

Neuromodulation for diabetic peripheral neuropathy represents a significant area of interest in the management of chronic pain associated with this condition. Diabetic peripheral neuropathy, a common complication of diabetes, is characterized by nerve damage due to high blood sugar levels that lead to symptoms, such as pain, tingling, and numbness, primarily in the hands and feet. The aim of this systematic review was to evaluate the efficacy of neuromodulatory techniques as potential therapeutic interventions for patients with diabetic peripheral neuropathy, while also examining recent developments in this domain. The investigation encompassed an array of neuromodulation methods, including frequency rhythmic electrical modulated systems, dorsal root ganglion stimulation, and spinal cord stimulation. This systematic review suggests that neuromodulatory techniques may be useful in the treatment of diabetic peripheral neuropathy. Understanding the advantages of these treatments will enable physicians and other healthcare providers to offer additional options for patients with symptoms refractory to standard pharmacologic treatments. Through these efforts, we may improve quality of life and increase functional capacity in patients suffering from complications related to diabetic neuropathy.

Prevalence and risk factors for painful diabetic peripheral neuropathy: a systematic review and meta-analysis

Objective

This study aimed to explore the prevalence and risk factors for painful diabetic peripheral neuropathy through meta-analysis, and to provide countermeasures for early intervention and active prevention of diabetic peripheral neuropathic pain.

Methods

We conducted a systematic search of PubMed, Embase, Web of Science, and Cochrane Library for articles published from the establishment of the database to November 2024. A total of 14 studies (nine cross-sectional studies and five cohort studies) qualified for meta-analysis. We used a random-effects meta-analysis and assessed heterogeneity and publication bias.

Results

A total of 14 studies (nine cross-sectional, five cohort) were included. The prevalence of PDPN was estimated at 33.9% (95% CI [19.4%-48.5%]). Significant risk factors included female gender (OR = 1.29, P = 0.004), glycosylated hemoglobin levels (WMD = 0.14, P < 0.001), nephropathy (OR = 1.41, P < 0.001), retinopathy (OR = 1.32, P = 0.040), cardiovascular disease (OR = 1.46, P < 0.001), arterial hypertension (OR = 1.25, P = 0.047), triglycerides levels (WMD = -0.10, P < 0.001), low density lipoprotein levels (WMD = -0.20, 1. 0.001), smoking (OR = 0.90, P = 0.001), drinking alcohol (OR = 0.87, P = 0.001), glomerular filtration rate levels (WMD = -7.11, P < 0.001), obesity (OR = 2.00, P = 0.001). The multivariate analysis results showed that female gender (OR = 1.42, P = 0.032), age of onset (OR = 1.19, P < 0.001), duration of diabetes (OR = 1.29, P < 0.001), and retinopathy (OR = 1.90, P = 0.032) were indicated as risk factors for painful diabetic peripheral neuropathy.

Conclusion

This meta-analysis suggests that female gender, glycosylated hemoglobin levels, nephropathy, retinopathy, cardiovascular disease, arterial hypertension, smoking, drinking alcohol, glomerular filtration rate levels, obesity, age of onset and duration of diabetes are indicated as risk factors for painful diabetic peripheral neuropathy in diabetic patients.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42025629060.

Acupuncture for the Management of Chronic Diabetic Peripheral Neuropathy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

AIM

Diabetic peripheral neuropathy (DPN) affects up to half of all patients with diabetes mellitus. Acupuncture is often used to manage chronic pain, but its' effects on DPN are uncertain. We conducted a systematic review and meta-analysis of randomized clinical trials (RCTs) to assess the effectiveness of acupuncture for DPN.

METHODS

We searched databases from inception to September 30, 2024. Paired reviewers independently extracted data and assessed risk of bias. We used random effects models for all meta-analyses and the GRADE approach to assess the certainty of evidence.

RESULTS

We included 14 RCTs (1,169 participants, 45% female). Low certainty evidence suggests that, compared to sham, acupuncture may reduce pain (weighted mean difference [WMD] -1.44 cm on a 10 cm VAS, 95%CI -1.72 to -1.15; modelled risk difference [RD] for achieving the minimally important difference [MID] of 1.5 cm: 45%, 95%CI 35-54%). Comparted to sham or usual care, low certainty evidence suggests that acupuncture may reduce overall neurological symptom severity (WMD - 1.22 [95%CI -1.85, -0.59] on the 19-point Toronto Clinical Scoring System [TCSS]), and provide little to no difference in physical functioning, mental functioning, or adverse events. Low certainty evidence suggests that, compared to amitriptyline or pregabalin, acupuncture may reduce pain associated with DPN.

CONCLUSIONS

Acupuncture for DPN may reduce pain when compared to sham acupuncture and may reduce neurologic symptom severity and result in little to no difference in physical functioning, mental functioning or adverse events, when compared with sham acupuncture or usual care.

Epidermal Transient Receptor Potential Vanilloid 1 innervation is increased in patients with painful diabetic polyneuropathy experiencing ongoing burning pain

ABSTRACT

Preclinical studies suggested that Transient Receptor Potential Vanilloid 1 (TRPV1) channels contribute to neuropathic pain in animal models of diabetic polyneuropathy. Patients with painful diabetic polyneuropathy commonly experience ongoing burning pain. This study aimed at evaluating the association between this specific type of pain and TRPV1 intraepidermal nerve fibers in patients with painful diabetic polyneuropathy. We consecutively enrolled 70 patients with diabetic polyneuropathy. Each patient completed the Neuropathic Pain Symptom Inventory (NPSI) to identify the various types of neuropathic pain. All patients underwent a distal leg skin biopsy, with immunostaining of skin nerve fibers using antibodies for the pan-axonal marker Protein Gene Product 9.5 (PGP9.5), TRPV1, Calcitonin Gene-Related Peptide (CGRP), and Substance P. We found that 57% of patients (n = 40) had neuropathic pain symptoms, with ongoing burning pain being the most frequently reported type of pain at the NPSI (70% of patients with pain, n = 28). Patients with ongoing burning pain had higher TRPV1 intraepidermal nerve fiber density and TRPV1/PGP9.5 ratio compared with those with painless polyneuropathy ( P = 0.014, P = 0.013) and painful polyneuropathy with other types of pain ( P < 0.0001, P = 0.024); they also had increased CGRP dermal nerve fiber density compared with patients with painless polyneuropathy ( P = 0.005). Our study showed that ongoing burning pain is associated with an increased expression of intraepidermal TRPV1 fibers, as well as an increased dermal representation of CGRP fibers. These findings suggest that TRPV1 contributes to ongoing burning pain, possibly in conjunction with elevated CGRP expression, highlighting its significance as a therapeutic target for patients with painful diabetic polyneuropathy.

Can Spinal Cord Stimulation be Considered as a Frontier for Chronic Pain in Diabetic Foot?

Chronic pain in the diabetic foot (DF) is a common complication of diabetes, bringing a significant burden to patients, their families, and even society. There is no very effective treatment for it, traditional treatments such as medication, lumbar sympathetic nerve block, and alternative therapies are often not very effective and have more adverse effects. The emergence of neuromodulation technology has brought new hope for the treatment of DF, among which spinal cord stimulation (SCS) is a hotspot in current research and has achieved remarkable efficacy in the study of DF treatment by blocking pain signaling and improving circulation and other mechanisms. This article reviews the SCS technique and clinical trails of SCS for chronic DF pain, and describes the prospects and current challenges of SCS.

Pharmacologic and Nonpharmacologic Management of Neuropathic Pain

Disorders of the somatosensory nervous system that cause neuropathic pain are treated in a variety of ways. Herein, we introduce a stepwise approach to treating neuropathic pain. We then summarize the available data and guidelines for treating neuropathic pain, both with pharmacologic and nonpharmacologic methods, and provide a synthesized algorithm highlighting the similarities and differences between recent guidelines on the management of neuropathic pain. Pharmacologic treatments are primarily antiseizure medications (e.g., gabapentinoids, sodium channel blockers) and antidepressant medications (e.g., tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors), though other medications and interventional pharmacologic therapies can also be considered. There are a wide variety of nonpharmacologic treatments for neuropathic pain including neuromodulation, nerve stimulation, physiotherapy, movement therapies, lifestyle modification, nutritional supplements, acupuncture, and mind-body techniques.

Promise of the gut microbiota in prevention and traditional Chinese medicine treatment of diabetic peripheral neuropathy

The pathogenesis of diabetic peripheral neuropathy (DPN) has not been fully elucidated, and treatment options are limited. Currently, the main strategies for treating DPN are strict glycemic control and symptomatic pain relief. In this editorial, we comment on an article by Li et al, which suggested that modulating the gut microbiota using traditional Chinese medicine (TCM) may be a promising strategy for alleviating DPN symptoms. The regulation of the gut microbiota has received widespread attention in the study of various diseases. TCM can participate in the regulation of gut microbiota through multiple mechanisms, and this regulatory effect can alleviate the clinical symptoms of DPN. We briefly analyzed the promise of the gut microbiota in the early diagnosis, treatment, and clinical efficacy of TCM for DPN. The gut microbiota has potential value at multiple nodes in the occurrence and progression of DPN.

Management of peripheral neuropathy associated with brentuximab vedotin in the frontline treatment of classical Hodgkin lymphoma

The ECHELON-1 trial demonstrated the effectiveness of brentuximab vedotin (BV) in combination with doxorubicin, vinblastine, and dacarbazine as a frontline treatment regimen in classical Hodgkin lymphoma. However, peripheral neuropathy (PN) is common with this regimen, occurring in up to two-thirds of patients. While standard prescribing information recommends BV dose modification at the onset of grade 2 PN, management strategies for PN are not well-defined. Most commonly, clinicians dose reduce or discontinue BV, vinblastine, or both. We review evidence-based and practical approaches for managing peripheral neuropathy, emphasizing early detection and dose modification.

Effectiveness of Duloxetine versus Other Therapeutic Modalities in Patients with Diabetic Neuropathic Pain: A Systematic Review and Meta-Analysis

Objectives: Diabetic peripheral neuropathy (DPN) is a chronic complication of diabetes mellitus (DM) with symptoms like intense pain and impaired quality of life. This condition has no treatment; instead, the pain is managed with various antidepressants, including duloxetine. The aim of this study is to analyze the evidence on the efficacy of duloxetine in the management of DPN. Methods: A systematic search in different databases was conducted using the keywords "diabetic neuropathy", "duloxetine therapy", "neuropathic pain", and "Diabetes Mellitus". Finally, eight studies were included in this meta-analysis. Results: All articles comparing duloxetine at different doses vs. a placebo reported significant differences in favor of duloxetine on pain scales like 24 h Average Pain Severity (standardized mean difference [SMD] = -1.06, confidence interval [CI] = -1.09 to -1.03, and p < 0.00001) and BPI Severity (SMD = -0.70, CI = -0.72 to -0.68, and p < 0.00001), among others. A total of 75% of the meta-analyses of studies comparing duloxetine at different doses showed a tendency in favor of the 120 mg/d dose. There were significant differences in favor of duloxetine when compared to routine care on the Euro Quality of Life (SMD = -0.04, CI = -0.04 to -0.03, and p < 0.00001) and SF-36 Survey (SMD = -5.86, CI = -6.28 to -5.44, and p < 0.00001) scales. There were no significant differences on the visual analog scale (VAS) when comparing duloxetine and gabapentin. Conclusions: Duloxetine appears to be effective in the management of DPN in different pain, symptom improvement, and quality of life scales.

Painful forms of diabetic neuropathy

Diabetic neuropathy is a frequent and severe degenerative complication of diabetes. The diagnosis is easily performed in painful symptomatic patients. Sensitivity disorders responsible for numbness, tingling, and loss of feeling are part and parcel of diabetic foot syndrome and require investigation in view of preventing trophic ulcers. To date, there exists no specific treatment for diabetic neuropathy possibly preventable by careful control of metabolic disorder. Effective management of diabetic patients would make it possible to limit the dramatic consequences of diabetic neuropathy while at the same time acting on other complications.

A Systematic Guideline by the ASPN Workgroup on the Evidence, Education, and Treatment Algorithm for Painful Diabetic Neuropathy: SWEET

Introduction

Painful diabetic neuropathy (PDN) is a leading cause of pain and disability globally with a lack of consensus on the appropriate treatment of those suffering from this condition. Recent advancements in both pharmacotherapy and interventional approaches have broadened the treatment options for PDN. There exists a need for a comprehensive guideline for the safe and effective treatment of patients suffering from PDN.

Objective

The SWEET Guideline was developed to provide clinicians with the most comprehensive guideline for the safe and appropriate treatment of patients suffering from PDN.

Methods

The American Society of Pain and Neuroscience (ASPN) identified an educational need for a comprehensive clinical guideline to provide evidence-based recommendations for PDN. A multidisciplinary group of international experts developed the SWEET guideline. The world literature in English was searched using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Meeting Abstracts, and Scopus to identify and compile the evidence for diabetic neuropathy pain treatments (per section as listed in the manuscript) for the treatment of pain. Manuscripts from 2000-present were included in the search process.

Results

After a comprehensive review and analysis of the available evidence, the ASPN SWEET guideline was able to rate the literature and provide therapy grades for most available treatments for PDN utilizing the United States Preventive Services Task Force criteria.

Conclusion

The ASPN SWEET Guideline represents the most comprehensive review of the available treatments for PDN and their appropriate and safe utilization.

Treatment of pain in length-dependent peripheral neuropathy with the use of spinal cord stimulation: a systematic review

BACKGROUND

Chronic intractable pain from peripheral neuropathy is a debilitating condition that might not respond to conventional medical management and pharmacotherapy. The primary objective of this systematic review was to assess change (or reduction) in pain intensity in patients with length-dependent peripheral neuropathy after spinal cord stimulation (SCS) therapy.

METHODS

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The primary outcome was change (or reduction) in pain intensity after 12 months of SCS therapy compared with baseline in participants with length-dependent peripheral neuropathy. Secondary outcomes included change in pain intensity after 6 months and change in opioid consumption after 12 months. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines were used to appraise the quality of evidence.

RESULTS

Nineteen studies consisting of 376 participants who underwent SCS implantation met the inclusion criteria. Qualitative synthesis revealed that all eligible studies reported a significant improvement in pain intensity after 12 months of SCS therapy as compared with baseline. Mean differences with 95% confidence intervals were calculated for 4 studies, all of which achieved the minimal clinically important difference for change in pain intensity at 12 months. The GRADE quality of evidence for this outcome was appraised as very low quality.

CONCLUSION

This systematic review highlights that SCS could lead to significant improvement in pain intensity for length-dependent peripheral neuropathy, although future well-powered randomized controlled trials are warranted to increase the certainty of evidence in this finding.

STUDY REGISTRATION

PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) ID: CRD42022377572.

Incidence of Neuraxial and Non-Neuraxial Hematoma Complications From Spinal Cord Stimulator Surgery: Systematic Review and Proportional Meta-Analysis

OBJECTIVE

The goal of this meta-analysis was to estimate the incidence of total hematomas, neuraxial hematomas, and non-neuraxial hematomas in patients who underwent temporary spinal cord stimulator (SCS) lead trial placement and permanent implantation of SCS leads and internal pulse generator (IPG).

MATERIALS AND METHODS

A comprehensive search was conducted of databases of any publications before October 21, 2021. Eligible study designs included randomized control trials and prospective or retrospective observational studies with more than ten patients. The primary outcome variables were the incidences of total hematomas, neuraxial hematomas, and non-neuraxial hematomas in patients with SCS. These dichotomous categorical outcomes were abstracted from studies after Freeman-Tukey arcsine square root transformation using random-effects meta-analysis (DerSimonian and Laird method). Pooled incidence rates and 95% CIs were calculated for each outcome variable.

RESULTS

A total of 40 studies met the inclusion criteria. Included in the neuraxial and non-neuraxial hematoma analyses were 4751 patients and 3862 patients, respectively. The pooled incidence of any hematoma in patients with SCS was 0.81% (95% CI, 0.45%-1.27%). The pooled incidence of neuraxial hematoma in patients with SCS was 0.32% (95% CI, 0.18%-0.50%). This included primarily epidural hematomas (11/4751) but also comprised an intracranial hemorrhage in a patient on enoxaparin bridge therapy from warfarin and one patient not on anticoagulation with an intracranial subdural hematoma that resulted in death. The pooled incidence of non-neuraxial hematomas in patients with SCS was 0.59% (95% CI, 0.29%-1.00%).

CONCLUSION

The overall incidence of hematomas in patients with temporary SCS trial lead placement and permanent SCS/IPG implantations is less than 1%. Furthermore, the incidence of neuraxial hematomas is less than 0.5%, which is of particular interest given the potential devastating consequences of this complication. The results of this study can be used to inform patients and implanting physicians on hematoma complications from SCS and highlight that the benefits of SCS outweigh the hematoma risks if anticoagulation is appropriately managed perioperatively.

A Brief Review on the Novel Therapies for Painful Diabetic Neuropathy

PURPOSE OF REVIEW

Almost half of people diagnosed with diabetes mellitus will develop painful diabetic neuropathy (PDN), a condition greatly impacting quality of life with complicated pathology. While there are different FDA approved forms of treatment, many of the existing options are difficult to manage with comorbities and are associated with unwanted side effects. Here, we summarize the current and novel treatments for PDN.

RECENT FINDINGS

Current research is exploring alternative pain management treatments from the first line options of pregabalin, gabapentin, duloxetine, and amitriptyline which often have side effects. The use of FDA approved capsaicin and spinal cord stimulators (SCS) has been incredibly beneficial in addressing this. In addition, new treatments looking at different targets, such as NMDA receptor and the endocannabinoid system, show promising results. There are several treatment options that have been shown to be successful in helping treat PDN, but often require adjunct treatment or alterations due to side effects. While there is ample research for standard medications, treatments such as palmitoylethanolamide and endocannabinoid targets have extremely limited clinical trials. We also found that many studies did not evaluate additional variables other than pain relief, such as functional changes nor were there consistent measurement methods. Future research should continue trials comparing treatment efficacies along with more quality of life measures.

Research trends and hotspots of neuropathic pain in neurodegenerative diseases: a bibliometric analysis

Background

Neuropathic pain is caused by a neurological injury or disease and can have a significant impact on people's daily lives. Studies have shown that neuropathic pain is commonly associated with neurodegenerative diseases. In recent years, there has been a lot of literature on the relationship between neuropathic pain and neurodegenerative diseases. However, bibliometrics is rarely used in analyzing the general aspects of studies on neuropathic pain in neurodegenerative diseases.

Methods

The bibliometric analysis software CiteSpace and VOSviewer were used to analyze the knowledge graph of 387 studies in the Science Citation Index Expanded of the Web of Science Core Collection Database.

Results

We obtained 2,036 documents through the search, leaving 387 documents after culling. 387 documents were used for the data analysis. The data analysis showed that 330 papers related to neuropathic pain in neurodegenerative diseases were published from 2007-2022, accounting for 85.27% of all published literature. In terms of contributions to the scientific study of neuropathic pain, the United States is in the top tier, with the highest number of publications, citations, and H-indexes.

Conclusion

The findings in our study may provide researchers with useful information about research trends, frontiers, and cooperative institutions. Multiple sclerosis, Parkinson's disease, and Alzheimer's disease are the three most studied neurodegenerative diseases. Among the pathological basis of neurodegenerative diseases, microglia-regulated neuroinflammation is a hot research topic. Deep brain stimulation and gamma knife radiosurgery are two popular treatments.

Where Art Thou O treatment for diabetic neuropathy: the sequel

INTRODUCTION

Having lived through a pandemic and witnessed how regulatory approval processes can evolve rapidly; it is lamentable how we continue to rely on symptoms/signs and nerve conduction as primary endpoints for clinical trials in DPN.

AREAS COVERED

Small (Aδ and C) fibers are key to the genesis of pain, regulate skin blood flow, and play an integral role in the development of diabetic foot ulceration but continue to be ignored. This article challenges the rationale for the FDA insisting on symptoms/signs and nerve conduction as primary endpoints for clinical trials in DPN.

EXPERT OPINION

Quantitative sensory testing, intraepidermal nerve fiber density, and especially corneal confocal microscopy remain an after-thought, demoted at best to exploratory secondary endpoints in clinical trials of diabetic neuropathy. If pharma are to be given a fighting chance to secure approval for a new therapy for diabetic neuropathy, the FDA needs to reassess the evidence rather than rely on 'opinion' for the most suitable endpoint(s) in clinical trials of diabetic neuropathy.

Incidence of Lead Migration With Loss of Efficacy or Paresthesia Coverage After Spinal Cord Stimulator Implantation: Systematic Review and Proportional Meta-Analysis of Prospective Studies and Randomized Clinical Trials

OBJECTIVE

The objective of this meta-analysis was to approximate the incidence of overall lead migration, clinically significant lead migration, and asymptomatic lead migration in patients who have undergone spinal cord stimulator implantation.

MATERIALS AND METHODS

A comprehensive literature search was performed for studies published before May 31, 2022. Only randomized controlled trials and prospective observational studies with more than ten patients were included. Two reviewers analyzed the articles from the literature search for final inclusion, after which, study characteristics and outcome data were extracted. The primary dichotomous categorical outcome variables were the incidence of overall lead migration, clinically significant lead migration (defined as lead migration resulting in loss of efficacy), and asymptomatic lead migration (defined as lead migration discovered incidentally on follow-up imaging) in patients with spinal cord stimulator implant. Freeman-Tukey arcsine square root transformation for meta-analysis of proportions using random effects (DerSimonian and Laird method) was used to calculate incidence rates for the outcome variables. Pooled incidence rates and 95% CIs were calculated for the outcome variables.

RESULTS

Fifty-three studies met the inclusion criteria, with a total of 2932 patients having received spinal cord stimulator implants. The pooled incidence of overall lead migration was 9.97% (95% CI of 7.62%-12.59%). Only 24 of the included studies commented on the clinical significance of reported lead migrations, of which every lead migration was clinically significant. In these 24 studies, 96% of the reported lead migrations required a revision procedure or explant. Unfortunately, no studies that reported lead migration commented on asymptomatic lead migrations; therefore, the incidence of asymptomatic lead migrations could not be defined.

CONCLUSIONS

This meta-analysis found that the rate of lead migration in patients who have received spinal cord stimulator implants is approximately one in ten patients. This likely closely approximates the incidence of clinically significant lead migration owing to the included studies not routinely performing follow-up imaging. Therefore, lead migrations were primarily discovered owing to loss of efficacy, and no included studies clearly reported asymptomatic lead migration. The results of this meta-analysis can be used to inform patients more accurately on the risks and benefits of spinal cord stimulator implantation.

IL-10/β-Endorphin-Mediated Neuroimmune Modulation on Microglia during Antinociception

Microglia are glial cells centrally related to pathophysiology and neuroimmunological regulation of pain through microglia-neuron crosstalk mechanisms. In contrast, anti-inflammatory mechanisms guided by immunological effectors such as IL-10 trigger the secretion of analgesic substances, culminating in the differential expression of genes encoding endogenous opioid peptides, especially β-endorphin. Thus, when β-endorphin binds to the µ-opioid receptor, it generates neuronal hyperpolarization, inhibiting nociceptive stimuli. This review aimed to summarize the recent advances in understanding the mechanism by which IL-10/β-endorphin can reduce pain. For this, databases were searched for articles from their inception up until November 2022. Two independent reviewers extracted the data and assessed the methodological quality of the included studies, and seventeen studies were considered eligible for this review. Several studies have demonstrated the impact of IL-10/β-endorphin in reducing pain, where IL-10 can stimulate GLP-1R, GRP40, and α7nAChR receptors, as well as intracellular signaling pathways, such as STAT3, resulting in increased β-endorphin expression and secretion. In addition, molecules such as gabapentinoids, thalidomide, cynandione A, morroniside, lemairamin, and cinobufagin, as well as non-pharmacological treatments such as electroacupuncture, reduce pain through IL-10 mediated mechanisms, reflecting a microglia-dependent β-endorphin differential increase. This process represents a cornerstone in pain neuroimmunology knowledge, and the results obtained by different studies about the theme are presented in this review.

Capsaicin: A Potential Treatment to Improve Cerebrovascular Function and Cognition in Obesity and Ageing

Impaired cognition is the primary symptom of dementia, which can lead to functional disability and reduced quality of life among an increasingly ageing population. Ageing is associated with increased oxidative stress, chronic low-grade systemic inflammation, and endothelial dysfunction, which reduces cerebrovascular function leading to cognitive decline. Chronic low-grade systemic inflammatory conditions, such as obesity, exacerbate this decline beyond normal ageing and predispose individuals to neurodegenerative diseases, such as dementia. Capsaicin, the major pungent molecule of chilli, has recently demonstrated improvements in cognition in animal models via activation of the transient receptor potential vanilloid channel 1 (TRPV1). Capsaicin-induced TRPV1 activation reduces adiposity, chronic low-grade systemic inflammation, and oxidative stress, as well as improves endothelial function, all of which are associated with cerebrovascular function and cognition. This review examines the current literature on capsaicin and Capsimax, a capsaicin supplement associated with reduced gastrointestinal irritation compared to capsaicin. Acute and chronic capsaicin treatment can improve cognition in animals. However, studies adequately assessing the effects of capsaicin on cerebrovascular function, and cognition in humans do not exist. Capsimax may be a potentially safe therapeutic intervention for future clinical trials testing the effects of capsaicin on cerebrovascular function and cognition.

Reversal of Neuralgia Effect of Beta Carotene in Streptozotocin-Associated Diabetic Neuropathic Pain in Female Zebrafish via Matrix Metalloprotease-13 Inhibition

Beta carotene is a natural anti-oxidant agent, and it inhibits the matrix metalloprotease (MMP) activity. Diabetic neuropathic pain (DNP) is produced by cellular oxidative stress. The role of the beta carotene effect in diabetic neuropathic pain is not explored yet. The present study is designed for the evaluation of the palm oil mill effluent-derived beta carotene (PBC) effect in DNP in zebrafish. The DNP was induced by the intraperitoneal administration of streptozotocin (STZ). Blood glucose levels of above 15 mM were considered to be diabetic conditions. The zebrafish were exposed to test compound PBC (25, 50, and 100 µM), pregabalin (PG: 10 μM), and an MMP-13 inhibitor (CL-82198; 10 μM) for 10 consecutive days from day 11. The neuralgic behavioral parameters, i.e., temperature test, acetic acid test, and fin clip test were assessed on day 0 and the 7th, 14th, and 21st days. On the 22nd day, the blood glucose and MMP-13 levels and brain thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), and MMP-13 activity levels were estimated. The treatment of PBC ameliorated the DNP-associated behavioral and biochemical changes. The results are similar to those of PG and CL-82198 treatments. Hence, the PBC possesses a potentially ameliorative effect against DNP due to its potential anti-oxidant, anti-lipid peroxidation, and MMP-13 inhibitory actions.

Treatment of Painful Diabetic Neuropathy Using Frequency Rhythmic Electro Magnetic Neural Stimulation (FREMS); Effectiveness in Daily Practice

Background

Painful diabetic peripheral neuropathy (PDPN) is common and difficult to treat with limited treatment options. We assessed the efficacy of frequency rhythmic electromagnetic neural stimulation (FREMS) in patients with PDPN.

Methods

An uncontrolled prospective survey of patients with PDPN and pain despite at least two lines of pharmacotherapy. The primary outcome, 50% reduction in pain scores at 1 and/or 3 months post FREMS. FREMS was applied to both legs below the knees using 4 sets of electrodes per leg; the treatment consisted of 10 sessions of 35 min applications given over 14 days. FREMS was repeated every 4 months and patients were followed up for 12 months. Pain was assessed using the neuropathic pain symptom inventory (NPSI) and quality of life (QOL) by the EQ-5D.

Results

Out of 336 subjects, 248 patients met the inclusion criteria (56% men), average age and diabetes duration were 65 and 12.6 years respectively. FREMS was associated with a median decrease NPSI of 31% at M1 (range -100;+93%), and a median decrease of -37.5% at M3 (range -100;+250%). The 50% reduction in pain was reached in 80/248 (32.3%) and 87/248 (35.1%) after M1 and M3 respectively. The change in NPSI was accompanied by a decrease in self reported use of opiates of >50%.

Conclusion

FREMS treatment was associated with a significant reduction in pain severity over a three months period in patients who did not have adequate response to pharmacotherapy. Randomised (sham)-controlled trials examining the role of FREMS as a treatment for PDPN in non-responders to pharmacotherapy are needed.

[Post-traumatic pain mononeuropathies]

Neuropathic pain syndrome (NPS) caused by peripheral nerve (PN) injury is a serious clinical problem due to its prevalence, complexity of pathogenesis, significant impact on the quality of life of patients. The issues of epidemiology, pathogenesis and treatment of patients with NBS with PN injury are considered. Modern possibilities of invasive treatment of such patients are discussed.

Implantable Peripheral Nerve Stimulation for Peripheral Neuropathic Pain: A Systematic Review of Prospective Studies

Peripheral nerve stimulation (PNS) has been utilized for over 50 years with accumulating evidence of efficacy in a variety of chronic pain conditions. The level and strength of evidence supporting the use of PNS for peripheral neuropathic pain remains unclear. The purpose of this review is to synthesize data from prospective studies on the efficacy of PNS for neuropathic pain as it pertains to pain intensity, neurological deficits/neuropathy (e.g., weakness, sensory deficits, gait/balance), and other secondary outcomes (quality of life, satisfaction, emotional functioning, and adverse events). In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, this review identified articles from MEDLINE(R), EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus. Overall, per the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria, pooled results demonstrate very low quality or low quality of evidence supporting modest to substantial improvement in pain and neurological function after PNS implantation for treatment of peripheral neuropathic pain. PNS for phantom limb pain was the only indication that had moderate level evidence. Future prospective and well-powered studies are warranted to assess the efficacy of PNS for peripheral neuropathic pain.

Neuromodulation Therapy for Chemotherapy-Induced Peripheral Neuropathy: A Systematic Review

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and painful condition in patients who have received chemotherapy. The role of neuromodulation therapy in treating pain and improving neurological function in CIPN remains unclear and warrants evidence appraisal. In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we performed a systematic review to assess change in pain intensity and neurological function after implementation of any neuromodulation intervention for CIPN. Neuromodulation interventions consisted of dorsal column spinal cord stimulation (SCS), dorsal root ganglion stimulation (DRG-S), or peripheral nerve stimulation (PNS). In total, 15 studies utilized SCS (16 participants), 7 studies utilized DRG-S (7 participants), and 1 study utilized PNS (50 participants). Per the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) criteria, there was very low-quality GRADE evidence supporting that dorsal column SCS, DRG-S, and PNS are associated with a reduction in pain severity from CIPN. Results on changes in neurological function remained equivocal due to mixed study findings on thermal sensory thresholds and touch sensation or discrimination. Future prospective, well-powered, and comparative studies assessing neuromodulation for CIPN are warranted.

Dorsal Root Ganglion Stimulation for Lower Extremity Neuropathic Pain Syndromes: An Evidence-Based Literature Review

Dorsal root ganglion stimulation (DRG-S) is a form of selective neuromodulation therapy that targets the dorsal root ganglion. DRG-S offers analgesia in a variety of chronic pain conditions and is approved for treatment of complex regional pain syndrome (CRPS) by the US Food and Drug Administration (FDA). There has been increasing utilization of DRG-S to treat various neuropathic pain syndromes of the lower extremity, although evidence remains limited to one randomized controlled trial and 39 observational studies. In this review, we appraised the current evidence for DRG-S in the treatment of lower extremity neuropathic pain using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) criteria. The primary outcome was change in pain intensity after DRG-S compared to baseline. We stratified presentation of results based of type of neuropathy (CRPS, painful diabetic neuropathy, mononeuropathy, polyneuropathy) as well as location of neuropathy (hip, knee, foot). Future powered randomized controlled trials with homogeneous participants are warranted.