Metabolic correction in the management of diabetic peripheral neuropathy: improving clinical results beyond symptom control

Current Perspectives in Pre- and Diabetic Peripheral Neuropathy Diagnosis and Management: An Expert Statement for the Gulf Region

Peripheral neuropathy (PN) significantly impacts the quality of life, causing substantial morbidity and increased mortality, as well as escalating healthcare costs. While PN can have various causes, the most common form, diabetic peripheral neuropathy, poses considerable risks for potential complications. Diabetic peripheral neuropathy (DPN) affects over 50% of people with prediabetes and diabetes. Despite its prevalence, a global gap in diagnosis and management exists, exacerbated by the COVID-19 pandemic. This expert consensus was formulated through a comprehensive evaluation by a panel of experts, informed by a focused literature review, aiming to establish a clinically robust approach to diagnosing and managing pre- and diabetic PN with the early utilization of neurotropic B vitamins. This document offers a consensus perspective on the existing challenges in diagnosing and managing PN, focusing on DPN. The expert panel proposes measures to address this underdiagnosed burden, highlighting the importance of early intervention through innovative screening methods, integrated care approaches, and therapeutic strategies. The document advocates for increased awareness, targeted campaigns, and proactive care strategies to bridge gaps in the patient care of individuals with diabetes, emphasizing the importance of early detection and timely management to improve overall health outcomes. Specific recommendations include incorporating simplified questionnaires and innovative screening methods into routine care, prioritizing neurotropic B vitamin supplementation, optimizing glucagon-like peptide 1 (GLP-1) receptor agonist treatments, and adopting a holistic approach to neuropathy management. The consensus underscores the urgent need to address the underdiagnosis and undertreatment of PN, offering practical measures to enhance early detection and improve health outcomes for individuals with DPN.

A Missing Puzzle in Preclinical Studies-Are CCR2, CCR5, and Their Ligands' Roles Similar in Obesity-Induced Hypersensitivity and Diabetic Neuropathy?-Evidence from Rodent Models and Clinical Studies

Research has shown that obesity is a low-grade inflammatory disease that is often associated with comorbidities, such as diabetes and chronic pain. Recent data have indicated that chemokines may play a role in these conditions due to their pronociceptive and chemotactic properties, which promote hypersensitivity and inflammation. Accumulating evidence suggests that CCR2, CCR5, and their ligands (CCL2, CCL3, CCL4, CCL5, CCL7, CCL8, CCL11 CCL12, and/or CCL13) play a role in rodent models of pain and obesity, as well as in patients with diabetes and obesity. It was proven that the blockade of CCR2 and CCR5, including the simultaneous blockade of both receptors by dual antagonists, effectively reduces hypersensitivity to thermal and mechanical stimuli in chronic pain states, including diabetic neuropathy. The present review discusses these chemokine receptors and the role of their ligands in diabetes and obesity, as well as their involvement in diabetic neuropathy and obesity-induced hypersensitivity.

Expert opinion on screening, diagnosis and management of diabetic peripheral neuropathy: a multidisciplinary approach

The proposed expert opinion aimed to address the current knowledge on conceptual, clinical, and therapeutic aspects of diabetic peripheral neuropathy (DPN) and to provide a guidance document to assist clinicians for the best practice in DPN care. The participating experts consider the suspicion of the disease by clinicians as a key factor in early recognition and diagnosis, emphasizing an improved awareness of the disease by the first-admission or referring physicians. The proposed "screening and diagnostic" algorithm involves the consideration of DPN in a patient with prediabetes or diabetes who presents with neuropathic symptoms and/or signs of neuropathy in the presence of DPN risk factors, with careful consideration of laboratory testing to rule out other causes of distal symmetric peripheral neuropathy and referral for a detailed neurological work-up for a confirmative test of either small or large nerve fiber dysfunction in atypical cases. Although, the first-line interventions for DPN are currently represented by optimized glycemic control (mainly for type 1 diabetes) and multifactorial intervention (mainly for type 2 diabetes), there is a need for individualized pathogenesis-directed treatment approaches for DPN. Alpha-lipoic acid (ALA) seems to be an important first-line pathogenesis-directed agent, given that it is a direct and indirect antioxidant that works with a strategy targeted directly against reactive oxygen species and indirectly in favor of endogenous antioxidant capacity for improving DPN conditions. There is still a gap in existing research in the field, necessitating well-designed, robust, multicenter clinical trials with sensitive endpoints and standardized protocols to facilitate the diagnosis of DPN via a simple and effective algorithm and to track progression of disease and treatment response. Identification of biomarkers/predictors that would allow an individualized approach from a potentially disease-modifying perspective may provide opportunities for novel treatments that would be efficacious in early stages of DPN, and may modify the natural course of the disease. This expert opinion document is expected to increase awareness among physicians about conceptual, clinical, and therapeutic aspects of DPN and to assist them in timely recognition of DPN and translating this information into their clinical practice for best practice in the management of patients with DPN.

Metformin improves diabetic neuropathy by reducing inflammation through up-regulating the expression of miR-146a and suppressing oxidative stress

PURPOSE

Diabetic neuropathy (DN) is a notable complication of diabetes mellitus. The potential involvement of miR-146a in DN regulation is presently under investigation. Metformin, a commonly prescribed medication for diabetes, is the primary therapeutic intervention. This study aimed to unveil the potential protective effects of metformin on diabetic neuropathy and explore the mechanisms underlying its action.

METHOD

Six-weeks male Sprague Dawley rats (n = 40) were randomly divided into 5 groups. The rat model of diabetic neuropathy (DN) was established by administering streptozotocin (STZ). To investigate the effects on the sciatic nerve and resident Schwann cells (RSCs), metformin and miR-146a mimics were administered, and our research explored the potential underlying mechanism.

RESULT

The sciatic nerve samples obtained from diabetic rats exhibited noticeable morphological damage, accompanied by decreased miR-146a expression (2.61 ± 0.11 vs 5.0 ± 0.3, p < 0.01) and increased inflammation levels (p65: 1.89 ± 0.04 vs 0.82 ± 0.05, p < 0.01; TNF-α: 0.93 ± 0.03 vs 0.33 ± 0.03, p < 0.01). Notably, the administration of metformin effectively ameliorated the structural alterations in the sciatic nerve by suppressing the inflammatory pathway (p65: 1.15 ± 0.05 vs 1.89 ± 0.04, p < 0.01; TNF-α: 0.67 ± 0.04 vs 0.93 ± 0.03, p < 0.01) and reducing oxidative stress (NO: 0.062 ± 0.004 vs 0.154 ± 0.004umol/mg, p < 0.01; SOD: 3.08 ± 0.09 vs 2.46 ± 0.09 U/mg, p < 0.01). The miR-146a mimics intervention group exhibited comparable findings.

CONCLUSION

This study's findings implied that metformin can potentially mitigate diabetic neuropathy in rats through the modulation of miR-146a expression.

Prevalence and disease burden of peripheral neuropathy in the general population in Mexico city: a cross-sectional epidemiological study

OBJECTIVE

Peripheral neuropathy (PN) is one of the most common diseases of the peripheral nervous system. Symptoms range from mild sensory signs to severe neuropathic pain. Untreated PN is progressive and can lead to complications and impair quality of life (QoL). However, PN prevalence is underestimated in the general population and affected individuals often remain undiagnosed. This study aimed to contribute to the global generation of prevalence data and determine sociodemographic and disease-related characteristics of PN sufferers.

METHODS

This cross-sectional study collected information on PN prevalence and associated factors in the adult population (40-65 years) of the Mexico City area. Participants were recruited in public places and screened for PN using the Michigan Neuropathy Screening Instrument (MNSI). Subjects with PN answered the Neuropathy Total Symptom Score-6 (NTSS-6), the Short Form-36 Health Survey (SF-36), and the QoL Pharmacoeconomic Questionnaire. Statistical analysis included descriptive methods and calculation of PN prevalence with 95% confidence intervals.

RESULTS

Of 3066 participants, 448 had PN based on the MNSI physical examination. The overall PN prevalence was 14.6%, with the highest (18.9%) seen in subjects aged 61-65 years. PN was undiagnosed in 82.6%, and 62.9% had never heard of PN. Although half of all subjects had only mild PN symptoms, QoL was impacted in 91.8%.

CONCLUSIONS

The results confirm that PN prevalence in the general population is high. Despite the disease burden, most affected persons are undiagnosed and unaware of the disease. Almost all felt their QoL was impacted. The data highlight the need to raise awareness and identify undiagnosed individuals to prevent complications.

Case series of retinal vein occlusions showing early recovery using oral l-methylfolate

This case series describes the aggregate rate of recovery in five consecutive subjects (six eyes) with retinal vein occlusion (RVO) who received l-methylfolate and other vitamins via Ocufolin®, a medical food. Subjects were followed for 10-33 months by a single ophthalmologist. Ocufolin® was prescribed at the time of diagnosis and subjects remained on the regimen throughout the time of observation. Examinations were performed in an un-masked fashion at 3-month intervals with recording of best corrected visual acuity (BCVA), average retinal nerve fiber layer (ARNFL) and central macular thickness (CMT), and fundus (examination of the retina, macula, optic nerve, and vessels) photography. Testing was done for vitamin deficiencies, vascular and coagulable risk factors, and methylenetetrahydrofolate reductase (MTHFR) polymorphisms. Vitamin deficiencies and vascular risk factors were found in all subjects, and all four tested subjects carried at least one MTHFR polymorphism. By the end of the study period BCVA in all subjects was 20/25 or better. Cystoid macular edema was identified and measured by optical coherence tomography (OCT). The percent change was calculated and plotted at 3-month intervals using the percent change in thickness from the time of diagnosis and percent change toward normative values for ARNFL and CMT. The total reduction in thickness of ARNFL and CMT from time of diagnosis was 44.19% and 30.27%, respectively. The comparison to normative data shows a reduction of ARNFL from 164.2% to 94% and CMT from 154.4% to 112.7% of normal thickness (100%). Plots showed the aggregate recovery was most rapid over the first 3 months and slowed over the next 3 months with most of the recovery taking place within 6 months of treatment. The rate of improvement in BCVA and resolution of retinal thickening was found to be better than predicted on historical grounds. No subjects progressed from nonischemic to ischemic RVO. Vitamin deficiencies, vascular risk factors, and genetic predisposition to oxidative stress were common in this RVO series. It appears that addressing these factors with Ocufolin® had a salutary effect on recovery.

Impact of Vitamin B6 Deficiency on the Severity of Diabetic Peripheral Neuropathy – A Cross Sectional Study

Background

Diabetic Peripheral Neuropathy is one of the most important and significantly prevalent microvascular complications of Diabetes Mellitus. Pyridoxine is a key nutrient for protecting nerve health. The objective of this research is to study the prevalence rate of pyridoxine deficiency in Diabetic neuropathy patients, to understand the correlation between various biochemical and markers of diabetic neuropathy and pyridoxine deficiency.

Results

249 patients were selected for the study based on the selection criteria participants. 51.8% prevalence of pyridoxine deficiency in Diabetic neuropathy patients. The nerve conduction velocity significantly reduced in pyridoxine deficiency cases (p < 0.05). A strong inverse relationship is observed with fasting blood sugar levels and glycated hemoglobin pyridoxine deficiency might contribute to impaired glucose tolerance.

Conclusion

There also exists a strong inverse relationship with glycemic markers. Significant direct correlation is observed with nerve conduction velocity. Pyridoxine also has properties of antioxidant which may be utilized for the management of Diabetic Neuropathy.

The efficacy of vitamin B12 supplementation for treating vitamin B12 deficiency and peripheral neuropathy in metformin-treated type 2 diabetes mellitus patients: A systematic review

BACKGROUND AND AIMS

Metformin-treated type 2 diabetes mellitus (T2DM) patients are at higher risk of vitamin B₁₂ deficiency and more severe neuropathy symptoms. There is still no guideline suggesting vitamin B₁₂ supplementation for this population. This study aimed to analyze the efficacy of vitamin B₁₂ supplementation in this population.

METHOD

Studies reporting the efficacy of vitamin B₁₂ supplementation in metformin-treated T2DM patients were systematically searched in PubMed, Cochrane, EBSCOHost, and Scopus following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Additional relevant studies were searched manually through citations. Study quality and risk of bias were assessed using suitable tools.

RESULTS

Seven clinical trials with a total of 506 participants were included. Using the Cochrane's Risk of Bias 2 tools for clinical trials, 4 studies were assessed to have high risk of bias and 3 studies had low risk of bias. There were 5 studies that measured changes in serum vitamin B₁₂ level, all of which reported a statistically significant increase after supplementation. Significant reductions in homocysteine after supplementation were found in 2 studies. Its effect on neuropathy symptoms was still unclear, with 2 studies reporting a significant improvement and 1 study reporting no significant effect.

CONCLUSIONS

The results of this systematic review support the implementation of vitamin B₁₂ supplementation for metformin-treated T2DM to prevent or treat vitamin B₁₂ deficiency and neuropathy. More high-quality clinical studies are required to generate quantitative analysis and to encourage supplementation in available guidelines.

Mechanistic approach towards diabetic neuropathy screening techniques and future challenges: A review

Diabetic neuropathy, also called peripheral diabetic neuropathy (PDN), is among the most significant diabetes health consequences, alongside diabetic nephropathy, diabetic cardiomyopathy and diabetic retinopathy. Diabetic neuropathy is the existence of signs and indications of peripheral nerve damage in patients with diabetes after other causes have been governed out. Diabetic neuropathy is a painful and severe complication of diabetes that affects roughly 20% of people. The development of diabetic neuropathy is regulated by blood arteries that nourish the peripheral nerves and metabolic problems such as increased stimulation of polyol pathway, loss of myo-inositol and enhanced non-enzymatic glycation. It's divided into four types based on where neurons are most affected: autonomic, peripheral, proximal, and focal, with each kind presenting different symptoms like numbing, gastrointestinal disorders, and heart concerns. Pharmacotherapy for neuropathic pain is complex and for many patients, effective treatment is lacking; as a result, scientific proof recommendations are crucial. As a result, the current demand is to give the most vital medications or combinations of drugs that work directly on the nerves to help diabetic neuropathy patients feel less pain without causing any adverse effects. In diabetic neuropathy research, animal models are ubiquitous, with rats and mice being the most typically chosen for various reasons. This review covers the epidemiology, clinical features, pathology, clinical symptom, mechanism of diabetic neuropathy development, diagnosis, screening models of animals, diabetic neuropathy pharmacotherapy.

How Well Do Current Laboratory Biomarkers Inform Clinical Decision-Making in Chronic Pain Management?

OBJECTIVE

Decision-making in chronic pain patients involves a combination of subjective and objective criteria, including patient history, physical examination, imaging, and patient response to prior treatments, clinical experience, probabilities, and recognition of patterns. However, there is a distinct lack of objective laboratory biomarkers in use in routine clinical care. The objective was to review the literature to identify and describe specific biomarkers in chronic pain management.

METHODS

This is a narrative review of the literature regarding the use of laboratory biomarkers in chronic pain. A librarian-assisted literature search of the PubMed, Science Direct, and Google Scholar databases was performed and resulted in 304 possible manuscripts. We included manuscripts assessing laboratory collected biomarkers from urine, serum, cerebrospinal fluid, and saliva. After screening and review of the initial literature search results, a total of 75 manuscripts were included in the narrative review.

CONCLUSION

The studies reviewed suggested that specific biomarkers may help identify those patients at risk of disease development and function as a prognostic indicator for disease progression and treatment response. However, additional research is necessary before specific recommendations can be made, and current clinical decision-making is modified.

Cross-Validation of the Foundation Pain Index with PROMIS-29 in Chronic Pain Patients

Purpose

Discovery and validation of pragmatic biomarkers represent significant advancements in the field of pain management. Evaluating relationships between objective biomarkers and patient-reported outcomes (PROs) is an effective way to gain mechanistic insight into the potential role of biochemistry in chronic pain. The aim of this study was to validate the Foundation Pain Index (FPI) by evaluating associations between deranged biochemical function and PROMIS-29 domains in individuals living with chronic pain.

Patients and Methods

PROMIS-29 scores and FPI test results were obtained from 298 patients with chronic pain in this retrospective, observational study. Statistical analysis was performed using clinical test data to evaluate relationships between deranged biochemical function and quality of life measures across 8 universal domains.

Results

FPI scores significantly associated with multiple PROMIS-29 domains including physical function, impact score, fatigue, pain interference, and depression (P < 0.05). Moreover, specific analytes that comprise the FPI significantly correlated with PROMIS-29 domains, including 5-hydroxyindolacetic acid (pain interference, physical function, and pain impact scores), hydroxymethylglutarate (physical function), homocysteine (pain impact scores), kynurenic acid (pain interference and physical function), and quinolinic acid (physical function) (P < 0.05).

Conclusion

Cross-validation of the FPI with PROMIS-29 domains further supports the role of deranged biochemical function in the etiology of chronic pain. Objective identification of atypical biochemical function and subsequent correction holds tremendous promise for the non-opioid management of pain. Continued research efforts will aim to determine the impact of biochemical optimization in pre-surgical periods and post-surgical outcomes in patients with chronic pain.

A Review of Alternative Treatment Options in Diabetic Polyneuropathy

Currently there is no recognized curative treatment for diabetic polyneuropathy (DPN). Strict glucose control and symptomatic pain relief are the first line management routes. DPN is a common complication of diabetes and has a major detrimental influence on the quality of life (QOL) for many patients. Due to the scope of the problem, it is imperative that treatment options which impede DPN's progression and restore sensorineural function should be researched comprehensively and made available to the masses at an economical cost. We reviewed a multitude of atypical treatment options for DPN including capsaicin, lidocaine, acupuncture, electrical nerve stimulation, alpha lipoic acid, benfotiamine, and acetyl-l-carnitine and explored the evidence to date regarding their safety and efficacy. Most of these options have been around for a long time and have promising pilot studies or small-scale trials focused on DPN treatment.

Clinical Validation of a Multi-Biomarker Assay for the Evaluation of Chronic Pain Patients in a Cross-Sectional, Observational Study

INTRODUCTION

Chronic pain assessment and post-treatment evaluation continues to be challenging due to a lack of validated, objective tools to measure patient outcomes. Validation of mechanistic pain biomarkers would allow clinicians to objectively identify abnormal biochemistry contributing to painful symptoms.

METHODS

We describe the clinical validation of a multi-biomarker assay with algorithmic analysis known as the Foundation Pain Index (FPI) in diverse cohorts of chronic pain patients in a prospective, cross-sectional, observational validation study. Levels of 11 urinary pain biomarkers were measured and tabulated using a proprietary algorithm to generate FPI scores for chronic pain subjects (N = 153) and age- and sex-matched pain-free controls (N = 334).

RESULTS

FPI scores were significantly correlated with the 36-Item Short Form Health Survey (SF-36) scores among chronic pain subjects (P value < 0.015) and specific components of SF-36, including emotional well-being, limitations due to emotional problems, and general health (P value < 0.05). Area under ROC analysis (AUROC) revealed FPI to accurately distinguish biomarker profiles between pain-free and chronic pain cohorts (AUROC: 0.7490, P value < 0.0001) as well as the SF-36 scores between chronic pain subjects with low vs. high FPI scores (AUROC: 0.7715, P value < 0.01).

CONCLUSIONS

Our findings establish the validity and discriminatory power of a novel multi-biomarker test that evaluates the role of biochemistry in chronic pain and correlates with clinical assessments of patients. This test provides novel, reproducible, objective data which may pave the way for non-opioid therapeutic strategies to treat chronic pain.

Transcriptome Analysis Reveals the Effects of Troxerutin and Cerebroprotein Hydrolysate Injection on Injured Spinal Cords in Rats

Spinal cord injury (SCI) is a serious condition that results in disability and has a high morbidity rate; its treatment is very difficult. Although troxerutin and cerebroprotein hydrolysate (TCH) injections have been extensively used in clinics in China for the treatment of traumatic brain injury (TBI) and cerebral stroke, the potential efficacy of TCH injection in the treatment of SCI has never been revealed. In this study, the effects of administering TCH injections on neurological recovery in post-SCI rats were first tested with regard to the behavior and histology; subsequently, the specific expression profile of mRNAs and long noncoding RNAs (LncRNAs) in their spinal cords were conducted using RNA sequencing (RNA-seq). The LncRNA-mRNA networks were also elucidated. After SCI, we found that TCH injection with the right dose is effective for the recovery of locomotion function and repairing of the damaged tissue in the spinal cord; TCH injection is also discovered to have a role in the regulation of 443 differentially expressed genes (DEGs) and 27 differentially expressed LncRNAs (DELs) that are identified to have multiple functions, including locomotion, blood vessel morphogenesis, thiamine metabolism, Hippo signaling pathway, and axon guidance, by applying the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and Gene Ontology (GO) analysis. In addition, it is revealed that, after SCI, the highly expressed LncRNA AABR07071383.1 in the post-SCI cis/trans-regulates the expression of mRNA Acpp mRNA that encodes a key enzyme involved in the metabolic process of thiamine in the abirritation of the dorsal root ganglion (DRG), which implies that TCH injection may be more effective when administered with benfotiamine (a common treatment drug).

Can the severity of central lumbar stenosis affect the results of nerve conduction study?

To evaluate the effect of the severity of spinal stenosis on the peripheral nerves of lower extremities by nerve conduction study (NCS).One hundred fifteen patients with lumbar spinal stenosis were recruited retrospectively in this study. The grading system for lumbar stenosis was used based on the degree of separation of the cauda equina. The degree of cauda equina damage caused by lumbar central stenosis was assessed by NCS of peripheral nerves. Multiple regression analysis was used to estimate which factors affect peripheral nerve injury, according to the presence of DM, total grading of lumbar central stenosis, and age.Only age was associated with low amplitude in the tibial and peroneal motor NCS in the multiple regression analysis. The severity of the compression of the cauda equina, caused by spinal stenosis, did not statistically significantly affect the NCS values of nerves on the lower extremities.In conclusion, the cauda equina is resilient against degenerative lumbar central stenosis. Unlike changes caused by peripheral nerve entrapment, lumbar central stenosis did not affect the findings of NCS on the peripheral nerve of lower extremities.

Randomized Trial on the Clinical Utility of a Novel Biomarker Panel to Identify Treatable Determinants of Chronic Pain

Millions suffer daily from chronic pain diagnosed anatomically and treated with opioids. Research shows that underlying nutritional, metabolic and oxidative stressors, which drive the development or worsening of chronic pain, are not diagnosed despite the fact that treatment of these primary pain pathways relieves pain and increases function. One of the main reasons for this gap in care is the lack of a simple diagnostic assay to help clinicians make these diagnoses. We examined the clinical utility of a urine-based pain biomarker panel. Primary care physicians were randomized into the test group and compared to controls. We measured their ability to make the diagnosis and treat a total of nine standardized patients, with common but challenging cases of chronic pain, over two rounds of data collection in a pre–post design using a fixed-effects model. Intervention doctors received educational materials on a novel pain biomarker panel after the baseline round and had access to biomarker test results. Provider responses were measured against evidence-based criteria. The two study arms at baseline provided similar, poor care for three different primary pain pathways: nutritional deficiencies (5.0% control versus 9.2% intervention treated, p = 0.208), metabolic abnormalities (1.0% control versus 0% for intervention treated, p = 0.314), and oxidative stress (1.2% control versus 0% intervention treated, p = 0.152). After the introduction of the Foundation Pain Index (FPI) biomarker test, physicians in the intervention group were 41.5% more likely to make the diagnosis of a micronutrient deficiency, 29.4% more likely to identify a treatable metabolic abnormality and 26.1% more likely to identify an oxidative stressor. These diagnostic and treatment improvements were seen across all three case types, ranging from a relative +54% (p = 0.004) for chronic neuropathic pain to +35% (p = 0.007) in chronic pain from other causes to +38% (p = 0.002) in chronic pain with associated mental health issues. Intervention doctors were also 75.1% more likely to provide a non-opioid treatment to patients on chronic opioids (O.R. 1.8, 95% C.I. 0.8–3.7), 62% less likely to order unnecessary imaging for their patients with low back pain (O.R. 0.38, 95% C.I. 0.15–0.97) and 66% less likely to order an unnecessary pain referral (O.R. 0.34, 95% C.I. 0.13–0.90). This experimental study showed significant clinical utility of a validated pain biomarker panel that determines nutritional deficiencies, metabolic abnormalities and oxidative stressors that drive underlying treatable causes of pain. When integrated into routine primary care practice, this testing approach could considerably improve diagnostic accuracy and provide more targeted, non-opioid treatments for patients suffering from chronic pain.

The impact of demographic and clinical characteristics on diabetic painful neuropathy

INTRODUCTION

Diabetic neuropathy (DN) is one of the most devastating complications of diabetes mellitus; however, in contrast to other countries, there are no scientific studies in Portugal evaluating the impact of demographic and clinical characteristics of this pathological entity. The aim of this study was to evaluate the impact of gender, metabolic control, age of diabetic patients, as well as time of disease progression, the appearance of complaints related to neuropathic pain.

MATERIAL AND METHODS

A multicentre study with a non-probabilistic, convenience sample of 359 patients was performed employing the quantitative method, using the Statistical Package for Social Science 24 software. The p-value of p < 0.05 was defined to consider a result statistically significant. The Spearman correlation coefficient (r) was determined to determine the relationship between categorical variables.

RESULTS

There was no statistically significant difference in the prevalence of DN between genders (p = 0.633 and r = 0.025). There was a statistically significant relationship between the value of HbA1c and DN, with p = 0.010 and r = 0.136. There is a relationship between age and complaints of neuropathic pain, with p = 0.034 and r = 0.112. The variable, time of disease progression, is also correlated with the appearance of complaints of neuropathic pain with p = 0.020 and r = 0.112.

CONCLUSION

The prevalence of neuropathic pain in subjects with diabetes is not negligible and is associated with modifiable risk factors that can be identified, possibly modified and prevented. The correct approach for these patients, which involves screening and early treatment, is decisive improving functionality and quality of life.

Integrative Approaches to Chemotherapy-Induced Peripheral Neuropathy

PURPOSE OF REVIEW

Chemotherapy-induced peripheral neuropathy (CIPN) is a common complication of cancer treatment, with conventional treatment limited in its ability for prevention or treatment of symptoms. This review addresses the research assessing the effectiveness and safety of complementary and integrative medicine (CIM) in preventing and treating CIPN-related symptoms.

RECENT FINDINGS

The CIM modalities acupuncture, classical massage, omega-3 fatty acids, and the Japanese Kampo medicine Goshanjishen may be of benefit in preventing or treating CIPN. Vitamin E (alpha-tocopherol), glutamine/glutamate, alpha-lipoic acid, and acetyl-L-carnitine (ALCAR) are not, with ALCAR increasing symptom severity and vitamin E the risk for developing prostate cancer. CIM therapies with a potential for preventing or treating CIPN-related symptoms should be further investigated. CIM is considered safe when provided within an integrative oncology setting, under the guidance and supervision of an integrative physician.

B Vitamins in the nervous system: Current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin

Background

Neurotropic B vitamins play crucial roles as coenzymes and beyond in the nervous system. Particularly vitamin B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) contribute essentially to the maintenance of a healthy nervous system. Their importance is highlighted by many neurological diseases related to deficiencies in one or more of these vitamins, but they can improve certain neurological conditions even without a (proven) deficiency.

Aim

This review focuses on the most important biochemical mechanisms, how they are linked with neurological functions and what deficits arise from malfunctioning of these pathways.

Discussion

We discussed the main role of B Vitamins on several functions in the peripheral and central nervous system (PNS and CNS) including cellular energetic processes, antioxidative and neuroprotective effects, and both myelin and neurotransmitter synthesis. We also provide an overview of possible biochemical synergies between thiamine, pyridoxine, and cobalamin and discuss by which major roles each of them may contribute to the synergy and how these functions are inter‐related and complement each other.

Conclusion

Taking into account the current knowledge on the neurotropic vitamins B1, B6, and B12, we conclude that a biochemical synergy becomes apparent in many different pathways in the nervous system, particularly in the PNS as exemplified by their combined use in the treatment of peripheral neuropathy.

Prediction of seed gene function in progressive diabetic neuropathy by a network-based inference method

Guilt by association (GBA) algorithm has been widely used to statistically predict gene functions, and network-based approach increases the confidence and veracity of identifying molecular signatures for diseases. This work proposed a network-based GBA method by integrating the GBA algorithm and network, to identify seed gene functions for progressive diabetic neuropathy (PDN). The inference of predicting seed gene functions comprised of three steps: i) Preparing gene lists and sets; ii) constructing a co-expression matrix (CEM) on gene lists by Spearman correlation coefficient (SCC) method and iii) predicting gene functions by GBA algorithm. Ultimately, seed gene functions were selected according to the area under the receiver operating characteristics curve (AUC) index. A total of 79 differentially expressed genes (DEGs) and 40 background gene ontology (GO) terms were regarded as gene lists and sets for the subsequent analyses, respectively. The predicted results obtained from the network-based GBA approach showed that 27.5% of all gene sets had a good classified performance with AUC >0.5. Most significantly, 3 gene sets with AUC >0.6 were denoted as seed gene functions for PDN, including binding, molecular function and regulation of the metabolic process. In summary, we predicted 3 seed gene functions for PDN compared with non-progressors utilizing network-based GBA algorithm. The findings provide insights to reveal pathological and molecular mechanism underlying PDN.

Comparison of the Effects of Prophylactic and Therapeutic Administrations on Peripheral Neuropathy in Streptozotocin-Diabetic Rats with Gliclazide or Methylcobalamin

OBJECTIVE

To observe the differences in curative effects between prophylactic and therapeutic administrations of Gliclazide (GLZ) or Methylcobalamin (MCA) on diabetic peripheral neuropathy in rats.

METHODS

GLZ (25 mg/kg/day) or MCA (175 μg/kg/day) was orally administrated prophylactically to streptozotocin-induced diabetic rats for 8 weeks before diabetic peripheral neuropathy developed or administrated therapeutically after diabetic peripheral neuropathy developed, respectively. The motor nerve conduction velocities (MNCV), aldose reductase (AR) activities, the polyol contents and antioxidative enzyme activities in the sciatic never tissues were determined. The morphology of sciatic never tissues was observed.

RESULTS

In comparison to vehicle, most of the changes in the sciatic nerves of the diabetic rats (e. g., delayed MNCV, altered/damaged nerve structure, enhanced AR activity, increased polyol contents, altered Cu, Zn-superoxide dismutase, glutathione-peroxidase activities, and elevated malondialdehyde level) were significantly ameliorated by prophylactic administration with either GLZ or MCA. In contrast, only few of above-mentioned parameters were alleviated in DPN rats by therapeutic administration with GLZ or MCA as compared to vehicle. The curative effects of GLZ or MCA prophylactic administration on MNCV, AR activity, polyol contents and antioxidative enzyme activities were markedly stronger than therapeutic administration.

CONCLUSION

Prophylactic administration of GLZ or MCA was superior to the therapeutic administration in alleviation of diabetic neuropathy in STZ-rats, suggesting that pharmacotherapy should be initiated at a much earlier stage before diabetic neuropathy developed, but not at a later stage after never damage reached.

Iatrogenic nerve lesion following laparoscopic surgery. A case report

BACKGROUND

Peripheral neuropathy after surgical treatment is an under recognized potential untoward event. Pelvic surgery may be associated with nerve lesions by essentially three main mechanisms: transection, entrapment and pressure-stretching; the latter is the modality most frequently linked to patient's positioning on the operating room table.

PRESENTATION OF THE CASE

A 25 years old woman, after undergoing a laparoscopic gynaecologic procedure lasted >3 hours, on postoperative day one presented with numbness over her lateral right leg and dorsum of the foot, right foot drop and gait instability due to compression-stretching of the right superficial peroneal nerve.

DISCUSSION

Patient's diagnostic work up, treatment and outcome are reported and measures on how to prevent the occurrence of such type of lesion are outlined together with the importance of an early postoperative diagnosis in order to avoid permanent nerve damage.

CONCLUSION

Such lesions are sometimes so unexpected that delayed diagnosis leads to damages which are difficult or impossible to repair. Primary prevention plays a key role and it is realized by adhering to specific protocols. In the occurrence of the lesion a prompt diagnosis is highly recommendable and a comprehensive therapeutic plan is necessary to correctly address the specific pathology.

Interactions between and Shared Molecular Mechanisms of Diabetic Peripheral Neuropathy and Obstructive Sleep Apnea in Type 2 Diabetes Patients

Type 2 diabetes (T2D) accounts for about 90% of all diabetes patients and incurs a heavy global public health burden. Up to 50% of T2D patients will eventually develop neuropathy as T2D progresses. Diabetic peripheral neuropathy (DPN) is a common diabetic complication and one of the main causes of increased morbidity and mortality of T2D patients. Obstructive sleep apnea (OSA) affects over 15% of the general population and is associated with a higher prevalence of T2D. Growing evidence also indicates that OSA is highly prevalent in T2D patients probably due to diabetic peripheral neuropathy. However, the interrelations among diabetic peripheral neuropathy, OSA, and T2D hitherto have not been clearly elucidated. Numerous molecular mechanisms have been documented that underlie diabetic peripheral neuropathy and OSA, including oxidative stress, inflammation, endothelin-1, vascular endothelial growth factor (VEGF), accumulation of advanced glycation end products, protein kinase C (PKC) signaling, poly ADP ribose polymerase (PARP), nitrosative stress, plasminogen activator inhibitor-1, and vitamin D deficiency. In this review, we seek to illuminate the relationships among T2D, diabetic peripheral neuropathy, and OSA and how they interact with one another. In addition, we summarize and explain the shared molecular mechanisms involved in diabetic peripheral neuropathy and OSA for further mechanistic investigations and novel therapeutic strategies for attenuating and preventing the development and progression of diabetic peripheral neuropathy and OSA in T2D.

Association between MTHFR variant and diabetic neuropathy

BACKGROUND

Methylene-tetrahydrofolate reductase (MTHFR) gene variant may play an important role in the pathophysiology of diabetes and its complications due to its influence on plasma homocysteine levels and also its effect on scavenging peroxynitrite radicals. Diabetic peripheral neuropathy (DPN) is one of the most common diabetic chronic complications. The aim of this study was to investigate the relationship between diabetic neuropathy and MTHFR gene C677T and 1298A ⁄C polymorphisms.

METHOD

Patients with type 2 diabetes N=248 were enrolled in the study, consisting of patients with neuropathy (N=141) and patients without neuropathy (N=107). MTHFR C677T polymorphism was analyzed using polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) of genomic DNA for genotyping of samples. 1298A/C polymorphism was evaluated using ARMS-PCR.

RESULT

There was a significant difference in MTHFR polymorphism between the groups with and without neuropathy.

CONCLUSION

Our results suggest that MTHFR 677 variant confer risk for diabetic neuropathy among Iranian patients with type 2 diabetes.

High-throughput chinmedomics-based prediction of effective components and targets from herbal medicine AS1350

This work was designed to explore the effective components and targets of herbal medicine AS1350 and its effect on “Kidney-Yang Deficiency Syndrome” (KYDS) based on a chinmedomics strategy which is capable of directly discovering and predicting the effective components, and potential targets, of herbal medicine. Serum samples were analysed by UPLC-MS combined with pattern recognition analysis to identify the biomarkers related to the therapeutic effects. Interestingly, the effectiveness of AS1350 against KYDS was proved by the chinmedomics method and regulated the biomarkers and targeting of metabolic disorders. Some 48 marker metabolites associated with alpha-linolenic acid metabolism, fatty acid metabolism, sphingolipids metabolism, phospholipid metabolism, steroid hormone biosynthesis, and amino acid metabolism were identified. The correlation coefficient between the constituents in vivo and the changes of marker metabolites were calculated by PCMS software and the potential effective constituents of AS1350 were also confirmed. By using chinmedomics technology, the components in AS1350 protecting against KYDS by re-balancing metabolic disorders of fatty acid metabolism, lipid metabolism, steroid hormone biosynthesis, etc. were deduced. These data indicated that the phenotypic characterisations of AS1350 altering the metabolic signatures of KYDS were multi-component, multi-pathway, multi-target, and overall regulation in nature.

Prevalence and Predictors of Metformin Prescribing in Adults with Type 2 Diabetes Mellitus: A National Cross-Sectional Study

OBJECTIVE

Metformin is the first-line oral type 2 diabetes treatment. Despite an abundance of evidence, metformin is routinely underused. This study evaluated the rates of metformin use in an appropriate outpatient type 2 diabetes population and identified predictors of metformin use.

METHODS

A national cross-sectional study was conducted using data from the National Ambulatory Medical Care Survey. Office visits involving patients aged 18-79 years with a diagnosis of type 2 diabetes were included, and visits involving patients with a diagnosis of chronic renal failure or heart failure were excluded. The primary outcome was metformin-prescribing rate. Multivariate logistic regression identified variables associated with metformin prescribing.

RESULTS

A total of 2348 patient visits were eligible for inclusion, representing 88,671,714 office visits nationally. Metformin was continued or initiated in 40.6% of these visits. The strongest independent predictors of metformin prescribing were insulin use (odds ratio [OR] 0.32; 95% confidence interval [CI] 0.21-0.47), presence of four or more chronic conditions (OR 0.58; 95% CI 0.34-0.98), patients with Medicare insurance (OR 0.57; 95% CI 0.39-0.83), visit with a surgical specialist (OR 0.39; 95% CI 0.25-0.61) or a medical specialist (OR 0.59; 95% CI 0.38-0.92), and Hispanic ethnicity (OR 2.03; 95% CI 1.28-3.22).

CONCLUSION

Metformin-prescribing rates are low, particularly in patients receiving insulin, with Medicare insurance, seen by medical or surgical specialists, or with four or more chronic conditions. The observed low rates of metformin use represent an important opportunity to improve the quality of care for patients with type 2 diabetes.

Alcohol Toxicity in Diabetes and Its Complications: A Double Trouble?

BACKGROUND

Eight percent of the U.S. population has been diagnosed with diabetes mellitus (DM), while another large percentage has gone undiagnosed. As the epidemiology of this disease constitutes a larger percentage of the American population, another factor presents a dangerous dilemma that can exacerbate the hazardous effects imposed by DM. Excessive alcohol consumption concerns the health of more than 50% of all adults. When this heavy-alcohol-drinking population overlaps with DM and its complications, the effects can be dangerous. In this review, we term it as "double trouble."

METHODS

We provide evidence of alcohol-induced exacerbation of organ damage in diabetic conditions. In certain cases, we have explained how diabetes and alcohol induce similar pathological effects.

RESULTS

Known exacerbated complications include those related to heart diseases, liver damage, kidney dysfunction, as well as retinal and neurological impairment. Often, pathophysiological damage concludes with end-stage disorders and even mortality. The metabolic, cell signaling, and pathophysiological changes associated with "double trouble" would lead to the identification of novel therapeutic targets.

CONCLUSIONS

This review summarizes the epidemiology, diagnosis, pathophysiology, metabolic, and cell signaling alterations and finally brushes upon issues and strategies to manage the "double trouble."

Non-linear contribution of serum vitamin D to symptomatic diabetic neuropathy: A case-control study

AIMS

Vitamin D deficiency has recently been speculated to be associated with increased risk of diabetes neuropathy (DN). The aim of this study was to evaluate the odds of symptomatic DN across serum vitamin D levels.

METHODS

All patients with DM were assessed using diabetic neuropathy symptoms and diabetic neuropathy examination score. Overall, 150 cases with DN and 600 controls were included. Serum 25-hydroxyvitamin D (25-OH-D) was measured to determine vitamin D status.

RESULTS

A non-linear association between 25-OH-D and suffering from symptomatic DN was observed which was extracted after stratifying the ORs across different serum 25-OH-D levels. When compared to individuals with 25-OH-D of 30-40 ng/mL, patients with deficient (<20 ng/mL) vitamin D levels had higher odds of having symptomatic DN (OR: 2.04, 95%CI: 0.99-4.02, P=0.054). Participants with vitamin D values of greater than 40 ng/mL were also more likely to exhibit symptomatic DN (fully adjusted OR: 4.29, 95%CI: 1.59-11.55).

CONCLUSIONS

We hypothesize a non-linear contribution of serum vitamin D to symptomatic DN occurrence, which emphasizes that administration of vitamin D should be monitored and evaluated more carefully, especially in patients with diabetes.

Nutritional management of patients with diabetic peripheral neuropathy with L-methylfolate-methylcobalamin-pyridoxal-5-phosphate: results of a real-world patient experience trial

OBJECTIVE

Current therapies for diabetic peripheral neuropathy with pain mask the painful symptoms while the underlying pathology continues to progress. This study assessed changes in symptoms and quality of life in patients taking a novel prescription medical food, L-methylfolate-methylcobalamin-pyridoxal-5-phosphate (LMF-MC-PP, Metanx ), intended to address the underlying metabolic needs of patients with diabetic peripheral neuropathy.

RESEARCH DESIGN AND METHODS

Between November 2010 and April 2012, patients rated their experiences before and after using LMF-MC-PP through an automated telephone system that included symptomatic items from the Neuropathy Total Symptom Score-6 (NTSS-6) questionnaire and questions related to quality of life and medication satisfaction.

RESULTS

A total of 544 patients participated in the study. Patients reported a mean reduction of 35% in NTSS-6 scores from after 12 weeks on LMF-MC-PP. Mean (standard deviation) score was reduced by 1.5 (1.8) at 12 weeks from a baseline of 4.3 (1.5) (p < 0.05). Patients achieved significant reductions in self-reported disruptions in work/school activities, social life, and family life, respectively. Overall pain rating decreased by 32% (p < 0.05). Patients previously treated with medications reported a 52% improvement in medication satisfaction (p < 0.05).

CONCLUSIONS

In a real-world clinical setting, patients with diabetic peripheral neuropathy treated with LMF-MC-PP achieved significant improvements in total symptom score (NTSS-6) and in quality of life and functioning, together with greater medication satisfaction. A limitation of this study was the use of a survey instrument to collect data on patient outcomes.

Natural products and complementary therapies for chemotherapy-induced peripheral neuropathy: A systematic review

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious dose-limiting side-effect without any FDA-approved treatment option. Prior reviews focus mostly on pharmacological interventions, but nonpharmaceutical interventions have also been evaluated. A Web of Science and PubMed database search to identify relevant RCTs from January 2005 to May 2015 included the terms: CIPN, cancer; and supplements, vitamin E, goshajinkigan, kampo, acetyl-L-carnitine, carnitine, alpha-lipoic acid, omega-3, glutamine, or glutamate; or massage, acupuncture, mind-body practice, yoga, meditation, Tai-Chi, physical activity, or exercise. Of 1465 publications screened, 12 RCTs evaluated natural products and one evaluated electroacupuncture. Vitamin E may help prevent CIPN. L-Glutamine, goshajinkigan, and omega-3 are also promising. Acetyl-L-carnitine may worsen CIPN and alpha-lipoic acid activity is unknown. Electroacupuncture was not superior to placebo. No RCTs were published regarding other complementary therapies, although some studies mention positive incidental findings. Natural products and complementary therapies deserve further investigation, given the lack of effective CIPN interventions.

Identifying Common Genetic Risk Factors of Diabetic Neuropathies

Type 2 diabetes mellitus (T2DM) is a global public health problem of epidemic proportions, with 60-70% of affected individuals suffering from associated neurovascular complications that act on multiple organ systems. The most common and clinically significant neuropathies of T2DM include uremic neuropathy, peripheral neuropathy, and cardiac autonomic neuropathy. These conditions seriously impact an individual's quality of life and significantly increase the risk of morbidity and mortality. Although advances in gene sequencing technologies have identified several genetic variants that may regulate the development and progression of T2DM, little is known about whether or not the variants are involved in disease progression and how these genetic variants are associated with diabetic neuropathy specifically. Significant missing heritability data and complex disease etiologies remain to be explained. This article is the first to provide a review of the genetic risk variants implicated in the diabetic neuropathies and to highlight potential commonalities. We thereby aim to contribute to the creation of a genetic-metabolic model that will help to elucidate the cause of diabetic neuropathies, evaluate a patient's risk profile, and ultimately facilitate preventative and targeted treatment for the individual.

Molecular strategies for targeting antioxidants to mitochondria: therapeutic implications

Mitochondrial function and specifically its implication in cellular redox/oxidative balance is fundamental in controlling the life and death of cells, and has been implicated in a wide range of human pathologies. In this context, mitochondrial therapeutics, particularly those involving mitochondria-targeted antioxidants, have attracted increasing interest as potentially effective therapies for several human diseases. For the past 10 years, great progress has been made in the development and functional testing of molecules that specifically target mitochondria, and there has been special focus on compounds with antioxidant properties. In this review, we will discuss several such strategies, including molecules conjugated with lipophilic cations (e.g., triphenylphosphonium) or rhodamine, conjugates of plant alkaloids, amino-acid- and peptide-based compounds, and liposomes. This area has several major challenges that need to be confronted. Apart from antioxidants and other redox active molecules, current research aims at developing compounds that are capable of modulating other mitochondria-controlled processes, such as apoptosis and autophagy. Multiple chemically different molecular strategies have been developed as delivery tools that offer broad opportunities for mitochondrial manipulation. Additional studies, and particularly in vivo approaches under physiologically relevant conditions, are necessary to confirm the clinical usefulness of these molecules.

Mechanisms and pharmacology of diabetic neuropathy - experimental and clinical studies

Neuropathic pain is the most common chronic complication of diabetes mellitus. The mechanisms involved in the development of diabetic neuropathy include changes in the blood vessels that supply the peripheral nerves; metabolic disorders, such as the enhanced activation of the polyol pathway; myo-inositol depletion; and increased non-enzymatic glycation. Currently, much attention is focused on the changes in the interactions between the nervous system and the immune system that occur in parallel with glial cell activation; these interactions may also be responsible for the development of neuropathic pain accompanying diabetes. Animal models of diabetic peripheral neuropathy have been utilized to better understand the phenomenon of neuropathic pain in individuals with diabetes and to define therapeutic goals. The studies on the effects of antidepressants on diabetic neuropathic pain in streptozotocin (STZ)-induced type 1 diabetes have been conducted. In experimental models of diabetic neuropathy, the most effective antidepressants are tricyclic antidepressants, selective serotonin reuptake inhibitors, and serotonin norepinephrine reuptake inhibitors. Clinical studies of diabetic neuropathy indicate that the first line treatment should be tricyclic antidepressants, which are followed by anticonvulsants and then opioids. In this review, we will discuss the mechanisms of the development of diabetic neuropathy and the most common drugs used in experimental and clinical studies.

Reproducibility of vibration perception threshold values in children and adolescents with type 1 diabetes mellitus and associated factors

AIMS

To define the reproducibility of vibration perception thresholds (VPTs) and the possible associated factors, as an early index of peripheral diabetic neuropathy (PDN) in type 1 diabetes mellitus (T1DM) children and adolescents.

METHODS

A single examiner studied 118 T1DM subjects (aged 13.5±3.4 years) and 79 controls (aged 12.0±3.07 years). Glycaemic control was assessed with HbA1c levels. VPT was measured twice on upper and lower limbs, using a Biothesiometer. Concordance between the two VPT measurements was evaluated using the Cohen's Weighted Kappa statistic (Kappa=0.41-0.60→moderate concordance, Kappa=0.61-0.80→substantial concordance).

RESULTS

T1DM children had significantly higher VPTs than controls at all sites (p=0.001), but with lower Kappa values (0.64-0.70). VPT values increased in parallel with HbA1c (a.<8%, b. 8-9.5%, c.>9.5%) and T1DM duration (a.<5 years, b.5.1-10, c.>10 years). However, Kappa values were lower in the groups with the poorest control (HbA1c>9.5%) (Kappa=0.54-0.76) or the longest T1DM duration (>10 years) (Kappa=0.49-0.71). Although VPTs increased with stature and male gender, no effect on VPT reproducibility was observed. However, obesity was associated with lower VPT values and poorer concordance.

CONCLUSIONS

These findings suggest that the reproducibility of VPTs is lower in the high-risk patients for early subclinical PDN development, who need a regular follow-up.

A clinical and neuropathological study of Chinese patients with diabetic peripheral neuropathy

OBJECTIVE

To examine whether the neuropathological and metabolic changes of peripheral nerves are correlated to clinical features in diabetes mellitus type 2 patients with peripheral neuropathy.

METHODS

147 type 2 diabetic patients with signs/symptoms of diabetic peripheralneuropathy (DPN) aged 53.4 ± 12.3 years and 134 healthy volunteers aged 55.5 ± 11.7 years were investigated for fasting plasma glucose (FPG), hemoglobin A1C (HbA1c), and red blood cell sorbitol (RBC sorbitol) in addition to nerve conduction velocity (NCV). Among the 147 diabetic patients, 10 patients underwent superficial peroneal nerve biopsy for light and electron microscopy.

RESULTS

In the experimental group, the levels of HbA1c and RBC sorbitol showed significant increase compared with the controlled group, whereas motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) both showed decline and SNCV decreased at a greater extent. Morphologically, there were various degrees of nerve fiber loss, associated with axon degeneration and capillary luminal narrowing in 10 patients undergone nerve biopsy.

CONCLUSION

The metabolic change of sorbitol, the consequently observed changes in NCV and histopathology of peripheral nerves are positively correlated with the duration of diabetes and overall level of blood glucose.

Intervention with vitamins in patients with nonproliferative diabetic retinopathy: a pilot study

Background

The purpose of this study was to determine whether a combination of vitamins B6, B9, and B12 is an effective intervention for reducing the signs and symptoms of nonproliferative diabetic retinopathy.

Methods

Ten subjects with type 2 diabetes mellitus (n = 20 eyes) with clinically diagnosed mild to moderate nonproliferative diabetic retinopathy were recruited from a private practice ophthalmology clinic for this open-label, uncontrolled, prospective six-month study. Metanx® vitamin tablets (containing 3 mg L-methylfolate calcium, 35 mg pyridoxal-5′-phosphate, and 2 mg methylcobalamin) were administered at a dosage of two tablets daily. Primary outcome indicators were the percent change in mean retinal sensitivity threshold measured by macular microperimetry and the percent change in mean central retinal thickness measured by spectral-domain optical coherence tomography.

Results

Three subjects were lost to follow-up. In the remaining seven subjects, two of 14 eyes had foveal edema that prevented microperimetry measurements due to poor fixation. The remaining 12 eyes showed a nonlinear improvement in mean threshold retinal sensitivity (P < 0.001). Overall change in mean central retinal thickness in 14 eyes was linear (R² = 0.625; P = 0.034), with a significant reduction between one and six months (P = 0.012).

Conclusion

In this pilot study, the Metanx intervention appeared to have some beneficial effects with respect to reducing retinal edema and increasing light sensitivity in subjects with nonproliferative diabetic retinopathy.

Beneficial effect of TNF-α inhibition on diabetic peripheral neuropathy

Background

Tumor necrosis factor-α (TNF-α) is an important inflammatory factor produced by activated macrophages and monocytes and plays an important role in the pathogenesis of diabetic peripheral neuropathy (DPN). To evaluate the effect of TNF-α signaling suppression and the potential of TNF-α in the treatment of DPN, a recombinant human TNF-α receptor-antibody fusion protein (rhTNFR:Fc) was used. We focused on the pathophysiology of the sciatic nerve and examined the expression of myelin basic protein (MBP) under DPN status with or without TNF-α inhibition.

Methods

The DPN rat model was generated by intraperitoneal injection of streptozotocin and by feeding with a high-fat, high-sugar diet. The nerve conduction velocity (NCV) in sciatic nerve of rat was monitored over a period of four weeks. The histopathological changes in nerve tissue were examined through traditional tissue histology and ultrastructure transmission electron microscopy (TEM). The expression of MBP was examined through western blot analysis.

Results

The DPN induced rats showed significant signs of nerve damage including lower NCV, demyelination of nerve fibers, disorganization of lamellar and axonal structures, and decreased expression of MBP in the nerve tissue. The inhibition of TNF-α in the DPN rats resulted in a significant recovery from those symptoms compared to the DPN rats.

Conclusions

Our study demonstrates that TNF-α plays a key role in the pathogenesis of DPN and its inhibition by rhTNFR:Fc can prove to be a useful therapeutic strategy for the treatment of and/or prevention from DPN symptoms.