Updates in diabetic peripheral neuropathy

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.

Deciphering the molecular landscape of human peripheral nerves: implications for diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is a prevalent complication of diabetes mellitus that is caused by metabolic toxicity to peripheral axons. We aimed to gain deep mechanistic insight into the disease process using bulk and spatial RNA sequencing on tibial and sural nerves recovered from lower leg amputations in a mostly diabetic population. First, our approach comparing mixed sensory and motor tibial and purely sensory sural nerves shows key pathway differences in affected nerves, with distinct immunological features observed in sural nerves. Second, spatial transcriptomics analysis of sural nerves reveals substantial shifts in endothelial and immune cell types associated with severe axonal loss. We also find clear evidence of neuronal gene transcript changes, like PRPH, in nerves with axonal loss suggesting perturbed RNA transport into distal sensory axons. This motivated further investigation into neuronal mRNA localization in peripheral nerve axons generating clear evidence of robust localization of mRNAs such as SCN9A and TRPV1 in human sensory axons. Our work gives new insight into the altered cellular and transcriptomic profiles in human nerves in DPN and highlights the importance of sensory axon mRNA transport as an unappreciated potential contributor to peripheral nerve degeneration.

Decreased glucagon in diabetic peripheral neuropathy patients with long duration type 2 diabetes

OBJECTIVE

The aim of this study was to investigate the association of fasting C-peptide and glucagon with diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes (T2DM).

METHODS

A comprehensive evaluation was conducted on 797 patients with T2DM to assess the various risk factors affecting DPN. The subjects were categorized into short duration and long duration group according to the duration of diabetes with a threshold of 10 years. Logistic regression analysis was employed to examine the association between DPN and islet function, as well as other parameters. Receiver operating characteristic curve analysis was performed to evaluate the predictive capability of glucagon.

RESULTS

The fasting C-peptide levels were significantly lower in the DPN patients with short duration of diabetes, but lost significance in the long duration group. Conversely, a decreased level of glucagon was only observed in DPN patients with long duration of diabetes. For the group with long duration of diabetes, glucagon was the sole risk factor associated with DPN. The receiver operating characteristic curve analysis revealed that glucagon in the long duration group exhibited a moderate area under the curve of 0.706.

CONCLUSIONS

The serum glucagon levels in T2DM patients with DPN exhibited bidirectional changes based on the duration of diabetes. Decreased glucagon was associated with DPN in T2DM patients with long duration of diabetes.

Matrix Metalloproteinase-9 Testing of Golden Rice Cookies With Piper Crocatum Active Extract for Preventing Foot Ulcers in Patients With Diabetes: Protocol for a Randomized Controlled Trial

BACKGROUND

Diabetic foot ulcers (DFUs) present a formidable challenge to both patients and health care systems. DFUs significantly reduce the quality of life for patients, prolong hospital stays, and are the cause of approximately 70,000 lower limb amputations across the globe annually. Prevention of DFUs primarily involves the optimization of blood sugar levels and the effective management of complications, particularly peripheral neuropathy. Golden Rice has been proven to lower blood sugar levels due to its beta-carotene content, and Piper crocatum (P. crocatum) has been found to be effective in reducing the risk factors of DFUs through biomolecular regulation because of its polyphenol content.

OBJECTIVE

The principal objective of this study is to identify the efficacy of P. crocatum-enriched cookies, with Golden Rice as their primary ingredient, in preventing DFUs. The evaluation will center on their impact on the expression of matrix metalloproteinase-9 (MMP-9), a pivotal factor in the development of DFUs.

METHODS

This study is an experimental clinical research that follows the randomized controlled trial method and uses a single-blind design. The participants in the study are outpatients from primary health centers in Makassar, Indonesia, who have been diagnosed with diabetes mellitus. The sample for the study will be randomly selected and subsequently categorized into 2 groups: the intervention group and the control group. The intervention group consumes P. crocatum-enriched Golden Rice cookies, while the control group receives cookies without these additives. The participants from both groups will consume their respective cookies (packaged identically) twice a day for 14 days. The cookies will be prepared according to a modified recipe with an emphasis on low glucose content, resulting in 51 calories per cookie, comprising 1% carbohydrates, 6% fat, 4% cholesterol, and 4% fiber, excluding gluten, sugar, and salt. They will be baked at 158°C for 20 minutes. The process involves the addition of 20% Golden Rice and 10% P. crocatum ethanol extract, both prepared via maceration with 96% ethanol. The dependent variable in this study is the expression of gelatinases matrix metalloproteinase, to be assessed at 2 distinct time points-preintervention (pretest) and postintervention (posttest)-with the evaluation conducted through the western blotting method.

RESULTS

The recruitment and testing phase started in January 2024. The study is scheduled to be completed by the end of March 2024. Data analysis will commence in April 2024, and the publication of the results is anticipated in the same year (2024). The study will report on the changes in primary data, encompassing gelatinases matrix metalloproteinase, as well as secondary data, including the ankle-brachial index, neuropathy score, and random blood glucose level.

CONCLUSIONS

The findings of this trial are expected to significantly impact the selection of strategies by health care practitioners to enhance diabetes self-management, particularly in the domain of therapeutic snacking, for patients diagnosed with diabetes mellitus.

TRIAL REGISTRATION

Thai Clinical Trials Registry TCTR20230502001; https://www.thaiclinicaltrials.org/show/TCTR20230502001.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/49940.

Serum SARM1 Levels and Diabetic Peripheral Neuropathy in Type 2 Diabetes: Correlation with Clinical Neuropathy Scales and Nerve Conduction Studies and Impact of COVID-19 vaccination

Patients with peripheral neuropathy with type 2 diabetes mellitus (T2DM) are more likely to have functional impairments. Recently, the gene for serum sterile alpha and toll/interleukin receptor motif-containing protein 1 (SARM1), which may contribute to the pathogenesis of Wallerian degeneration, was discovered in mice models of peripheral neuropathy. We set out to assess serum SARM1's activity as a potential biomarker for the early identification of diabetic peripheral neuropathy in T2DM patients while also examining the impact of the COVID-19 vaccine on SARM1 levels. We assessed the cross-sectional relationships between the SARM1 biomarker, clinical neuropathy scales, and nerve conduction parameters in 80 participants aged between 30 years and 60 years. The analysis was carried out after the patients were split into two groups since we discovered a significant increase in SARM1 levels following the second dose of the COVID-19 vaccination, where group A received one dose of the COVID-19 vaccine inoculation, and group B received two doses of the COVID-19 vaccine. SARM1 was correlated significantly (p < 0.05) with MNSIe and NSS in group A and showed a consistent positive correlation with the other neuropathy clinical scales in group A and group B without reaching statistical significance. Additionally, SARM1 was negatively correlated significantly (p < 0.05) with the median sensory amplitude in group A and showed a consistent negative correlation with the six other sensory and motor nerves' potential amplitude in group A and group B without reaching statistical significance. In conclusion, SARM1 showed a consistent correlation with clinical neuropathy scales and nerve conduction parameters after accounting for the influence of COVID-19 vaccination doses.

Evaluating the Diagnostic Potential of Serum Vascular Endothelial Growth Factor and Adiponectin in Diabetic Peripheral Neuropathy

INTRODUCTION

Diabetic peripheral neuropathy (DPN) presents a formidable health challenge in type 2 diabetes mellitus (T2DM) patients. This study in eastern Uttar Pradesh aims to assess the roles of vascular endothelial growth factor (VEGF) and adiponectin in DPN, recognizing the crucial need for understanding its molecular underpinnings for enhanced diagnosis and management.

METHODS

In a cross-sectional study analyzing clinical and biochemical data, 86 individuals aged 35 to 65 years were examined, including 43 with neuropathy and 43 without. Neuropathy assessment included the neuropathy symptom score (NSS), diabetes neuropathy examination (DNE) score, and nerve conduction studies. Levels of VEGF and adiponectin were correlated with motor nerve amplitude, NSS, and DNE scores. Receiver operating characteristic (ROC) curve analysis gauged diagnostic potential, and logistic regression assessed predictors for DPN.

RESULTS

Patients with neuropathy exhibited significantly elevated VEGF levels compared to those without, while adiponectin showed no significant difference. VEGF demonstrated a negative correlation with motor nerve amplitude and a positive correlation with NSS and DNE scores. ROC analysis revealed strong diagnostic capability for VEGF (area under the curve: 0.807). NSS and DNE scores indicated good and moderate diagnostic accuracy, respectively. In logistic regression analysis, VEGF emerged as the sole significant predictor (odds ratio: 1.11, 95% CI (1.03, 1.20), p = 0.0092).

CONCLUSION

Findings suggest VEGF's potential as a biomarker for diagnosing DPN in T2DM, associated with neuropathy severity. Adiponectin showed no significant association. The study underscores NSS and DNE scores' therapeutic relevance as valid neuropathy assessment tools.

The Need for Early Screening of Diabetic Peripheral Neuropathy and Diabetic Foot in MENA Region: A Review

BACKGROUND

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes mellitus. Among all complications of DPN, diabetic foot (DF) can cause a myriad of symptoms and impact the quality of life. This study aimed to review the prevalence of DPN and DF in the Middle East and North Africa (MENA) region based on the publications available. This systematic review can be a cornerstone for further research and it summarizes the literature published on the prevalence of DPN and DF for the last two decades in the MENA region.

METHODOLOGY

The databases, PubMed, ResearchGate, Scopus, Web of Science, Science Direct, CINAHL, and Cochrane were searched using relevant keywords for the study. Full articles in English since 2000, including keywords "Prevalence", "Diabetic peripheral neuropathy", "Diabetic foot", and "MENA region" were reviewed in two phases. All authors screened the titles and abstracts of the articles individually, which was followed by a screening of full texts. A consensus was made among all the authors for the final selection of the articles based on the eligibility criteria.

RESULTS

Ten selected articles on the prevalence of DPN were reviewed in the first phase of the study, which reported varying prevalence rates among the different countries of the MENA region ranging from 9% to 61%. In the second phase, only two articles on DF prevalence were shortlisted. They reported the prevalence of DF as 4.6% and 18.1% in Jordan and Sudan, respectively.

CONCLUSION

The prevalence of DPN in the MENA region is varied within a short period of time and the reported prevalence of DF is limited. This study projects a strong need of establishing early screening strategies for DPN and DF to prevent further complications and decrease healthcare burden.

Effects of Neural Mobilization in Diabetic Peripheral Neuropathy: A Scoping Review

Objective

The purpose of this scoping review was to explore the effects of neural mobilization (NM) on outcomes in adults with diabetic peripheral neuropathy (DPN).

Methods

Five databases were searched-PubMed, Web of Science (Web of Science Core Collection), Physiotherapy Evidence Database (PEDro), and Scopus-from inception to January 2022. The studies included were randomized controlled trials, pre-post single group design, multiple case studies, controlled case studies, quasi-experimental studies, and single case studies, which are published in full text in English.

Results

Six studies were included in this review, and most were of low-level evidence. The sample size of the studies ranges from 20 to 43, except for 1 case study, with a total of 158 participants in all the studies combined. In 4 out of 6 studies, only NM was given, whereas in 2 studies, NM was used along with other treatment strategies. The tibial nerve was the most studied nerve, whereas 1 study administered NM to nerves of the upper limbs, and only 1 trial examined the sciatic nerve. The outcomes included the Michigan Neuropathy Screening Instrument questionnaire, nerve conduction velocity, vibration perception threshold, heat/cold perception threshold, weight-bearing asymmetry and range of motion of lower limb, quality of life, and magnetic imaging changes.

Conclusion

At present, only a few low-level studies exist on the use of NM for the treatment of adults with DPN. The evidence for use of NM on DPN is still limited and insufficient.

Acute short term effects of endurance and resistance training on balance control in patients with diabetic peripheral neuropathy

PURPOSE

Exercise training have numerous beneficial effects on the complications of diabetic peripheral neuropathy. Exercise training may cause immediate effects on balance control in DPN patients. This study aims to assess the Acute Short Term effects of endurance and resistance exercise training on balance control in DPN patients.

METHODS

In this study, 11 patients with DPN and 11 healthy subjects participated. Patients and healthy subjects did endurance and resistance training in two separate exercise sessions. Dynamic balance and functional balance test were assessed before and after the interventions. Independent t-test was used to compare balance indices before and after training, the intervention effects were examined using ANOVA repeated measure test. The statistical significance level was set at p < 0.05.

RESULTS

The results showed that dynamic and functional balance in DPN patients were significantly lower than in healthy subjects. Anterior-posterior stability and total stability indices and functional balance test deteriorated significantly after training.

CONCLUSION

Endurance or resistance training may lead to acute disturbance of dynamic and functional balance in DPN patients. Hence, immediately after exercise, patients with diabetes are at an increased risk of falling, therefore, preventive considerations are necessary.

Efficacy of Habb-e-Asab in diabetic peripheral neuropathy: a randomized placebo control study

OBJECTIVES

Diabetic peripheral neuropathy (DPN) is a common diabetes complication. The prevalence of neuropathy is 55% for type 1 and 66% for type 2 diabetes. In Unani medicine neuropathy is known as Khidr (numbness). It is treated with drugs possessing hypoglycemic and analgesic properties, etc. Habb-e-Asab, a polyherbal Unani formulation used for the treatment of Waja-ul-Asab (neuralgia) is routinely used for its indications in neurological pain in Unani medicine. The aim of this study to investigate the efficacy of Habb-e-Asab in diabetic peripheral neuropathy.

METHODS

Thirty patients with DPN were randomly assigned to test (n=20) and control (n=10) groups in a randomized single-blind placebo control study. For 45 days, the test group was given 250 mg Habb-e-Asab twice a day and the control group 250 mg placebo twice a day. The subjective parameters Pain in feet, burning in feet, and tingling in feet was assessed by the arbitrary scale and VAS fortnightly and objective parameters MNSI, and VPT was assessed in pre-post-treatment.

RESULTS

The research drug revealed highly statistically significant with p<0.001 on VAS score and MNSI whereas VPT is significant with p<0.01 on few points. But control group exhibits no significant effect in any of the parameters. No adverse effects had been reported in either group.

CONCLUSIONS

Our finding indicated that the Habb-e-Asab for 45 days improved and reduced the severity of DPN in a patient with diabetes (CTRI/2018/02/011725).

Why too soon? Predictors of time to diabetic peripheral neuropathy among newly diagnosed diabetes mellitus patients: a multicenter follow-up study at health-care setting of Ethiopia

BACKGROUND

Due to the rising number of diabetic patients, the burden of diabetic peripheral neuropathy (DPN) is clearly posing a major challenge to the long-term viability of the health-care system. Despite this, most DPN epidemiological research in eastern Africa, including Ethiopia, has so far been limited to survey studies. Thus, we determined the incidence of DPN and its predictors among diabetic patients in tertiary health-care setting of southwest Ethiopia.

METHODS

A multicenter retrospective follow-up study was carried out on 567 randomly selected diabetic patients. Data were entered using Epi-Data v4.6 and analyzed using R v4.0.4. The survival curves were estimated using the Kaplan-Meier, and compared using Log-rank test between groups of categorical variables. The PHA were evaluated using the Schoenfeld residuals test. Multivariable Gompertz proportional hazard model was used to examine the predictors of DPN at 5% level of significance.

RESULTS

Overall, of 567 DM patients 119 developed DPN with an incidence rate of 3.75, 95%CI [3.13, 4.49] per 100 PY. About 15.13% and 69% of DPN cases occurred within 2 and 5 years of DM diagnosis, respectively. In the multivariable Gompertz PH model, being female [AHR = 1.47; 95% CI (1.01, 2.15)], T2DM [AHR = 3.49 95% CI (1.82, 6.71)], having diabetic retinopathy [AHR = 1.9 95% CI (1.25, 2.91)], positive proteinuria [AHR = 2.22 95% CI (1.35, 3.65)], being obese [AHR = 3.94 95% CI (1.2, 12.89)] and overweight [AHR = 3.34 95% CI (1.09, 10.25)] significantly predicts the future risk of DPN.

CONCLUSION

Nearly, 7 in 10 of DPN cases occurred within short period of time (5 year) of DM diagnosis. Being female, T2DM, DR, positive proteinuria, obese and overweight significantly predicts the risk of DPN. Therefore, we recommend screening and early diagnosis of diabetes with its complication. While doing so, attention should be given for DM patients with DR and positive proteinuria at baseline.

Transcriptomic analysis of diabetic kidney disease and neuropathy in mouse models of type 1 and type 2 diabetes

Diabetic kidney disease (DKD) and diabetic peripheral neuropathy (DPN) are common complications of type 1 (T1D) and type 2 (T2D) diabetes. However, the mechanisms underlying pathogenesis of these complications are unclear. In this study, we optimized a streptozotocin-induced db/+ murine model of T1D and compared it to our established db/db T2D mouse model of the same C57BLKS/J background. Glomeruli and sciatic nerve transcriptomic data from T1D and T2D mice were analyzed by self-organizing map and differential gene expression analysis. Consistent with prior literature, pathways related to immune function and inflammation were dysregulated in both complications in T1D and T2D mice. Gene-level analysis identified a high degree of concordance in shared differentially expressed genes (DEGs) in both complications and across diabetes type when using mice from the same cohort and genetic background. As we have previously shown a low concordance of shared DEGs in DPN when using mice from different cohorts and genetic backgrounds, this suggests that genetic background may influence diabetic complications. Collectively, these findings support the role of inflammation and indicate that genetic background is important in complications of both T1D and T2D.

Acupuncture treated oculomotor nerve palsy with diabetes mellitus: A case reported

The incidence of diabetes mellitus is increasing rapidly, and this condition often results in severe complications. One such complication, diabetic oculomotor nerve palsy (ONP), that can lead to significant impairment of visual function is increasingly recognized. However, there are few reports in the literature on the treatment of diabetic ONP. In the present case, the use of needling a selection of local and distal acupoints showed promising results for the treatment of diabetic ONP. We also present a brief literature review related to this case.

The prevalence of peripheral neuropathy among the patients with diabetes in Pakistan: a systematic review and meta-analysis

The most frequent complication of diabetes is peripheral neuropathy. The estimated prevalence of peripheral neuropathy in people with diabetes varies substantially between published studies in Pakistan. We conducted this meta-analysis to summarize the prevalence of peripheral neuropathy in people with diabetes. Different electronic databases were systematically searched using keywords and MeSH terms. Random-effects meta-analysis was conducted to pool the prevalence of peripheral neuropathy in people with diabetes in Pakistan. Heterogeneity was investigated by random-effects meta-regression and stratification. Two independent authors reviewed studies, extracted data, and conducted the risk of bias analysis. Nineteen studies with a total of 8487 diabetic patients were included. The overall pooled prevalence of diabetic peripheral neuropathy was 43.16% (95% CI 32.93-53.69%), with significant heterogeneity between estimates. The prevalence of peripheral neuropathy among those newly diagnosed with diabetes was 26.52% (95% CI 14.97-39.96%, n = 5). According to the subgroup meta-analysis, the pooled prevalence of diabetic peripheral neuropathy was highest in Khyber Pakhtunkhwa (55.29%; 95% CI 23.91-84.50%), followed by Sindh (40.04%; 95% CI 24.00-57.25%), and the lowest was found in Punjab (34.90%; 95% CI 15.05-57.95%). A significant association was found between the pooled prevalence estimate and the duration of diabetes. The results of this meta-analysis indicate a relatively high prevalence of peripheral neuropathy in people with diabetes in Pakistan. The study protocol has been registered in the PROSPERO, with the registration number CRD42022371617.

l-Methylfolate in Diabetic Peripheral Neuropathy: A Narrative Review

OBJECTIVE

One of the most frequently occurring complications of diabetes mellitus is peripheral neuropathy. Despite the painful symptoms associated with diabetic peripheral neuropathy (DPN), the current treatment landscape focuses on managing symptoms without addressing the underlying causes of DPN. This narrative review describes the mechanistic effects and clinical trial data supporting the use of l-methylfolate calcium (LMF), the bioactive form of folate, which is available in the United States as a prescription medical food that also contains other B vitamins for the dietary management of DPN.

METHODS

Preclinical and clinical trial data evaluating the impact of LMF on DPN was identified using PubMed searches for articles published between 2010 and 2023. Search terms included: folate, l-methylfolate, diabetes, neuropathy, and neuropathic pain. Additionally, a literature search was conducted to identify studies related to LMF, genetic polymorphisms, and DPN pathophysiology.

RESULTS

Several studies show that the C677T variant of the methylenetetrahydrofolate reductase (MTHFR) gene is linked to greater risk of DPN than other MTHFR variants due to its inhibitory effects on several folic acid metabolic pathways. One double-blind, randomized controlled trial, five open-label studies, and one retrospective study found that LMF has a significant beneficial effect on DPN that extends beyond symptomatic relief to include modulating the underlying pathophysiology that leads to the progression and symptoms of DPN. LMF also significantly improves patient quality of life, with minimal adverse effects.

CONCLUSION

Preclinical and clinical studies have found that LMF can be used to treat the underlying causes of DPN and provide long-lasting symptomatic relief.

Biomarkers in diabetic neuropathy

CONTEXT

The prevalence of diabetic neuropathy is drastically increasing in the world. To halt the progression of diabetic neuropathy, there is an unmet need to have potential biomarkers for the diagnosis and new drug discovery.

OBJECTIVE

To study various biomarkers involved in the pathogenesis of diabetic neuropathy.

METHODS

The literature was searched with the help of various scientific databases and resources like PubMed, ProQuest, Scopus, and Google scholar from the year 1976 to 2020.

RESULTS

Biomarkers of diabetic neuropathy are categorised as inflammatory biomarkers such as MCP-1, VEGF, TRPV1, NF-κB; oxidative biomarkers such as adiponectin, NFE2L2; enzyme biomarkers like NADPH, ceruloplasmin, HO-1, DPP-4, PARP α; miscellaneous biomarkers such as SIRT1, caveolin 1, MALAT1, and microRNA. All biomarkers have a significant role in the pathogenesis of diabetic neuropathy.

CONCLUSION

These biomarkers have a potential role in the progression of diabetic neuropathy and can be considered as potential targets for new drug discovery.

Lower Extremity Nerve Conduction Abnormalities in Vietnamese Patients with Type 2 Diabetes: A Cross-Sectional Study on Peripheral Neuropathy and Its Correlation with Glycemic Control and Renal Function

Peripheral neuropathy is a common complication of type 2 diabetes mellitus (T2DM) that results in nerve conduction abnormalities. This study aimed to investigate the parameters of nerve conduction in lower extremities among T2DM patients in Vietnam. A cross-sectional study was conducted on 61 T2DM patients aged 18 years and older, diagnosed according to the American Diabetes Association’s criteria. Data on demographic characteristics, duration of diabetes, hypertension, dyslipidemia, neuropathy symptoms, and biochemical parameters were collected. Nerve conduction parameters were measured in the tibial and peroneal nerves, including peripheral motor potential time, response amplitude M, and motor conduction speed, as well as sensory conduction in the shallow nerve. The study found a high rate of peripheral neuropathy among T2DM patients in Vietnam, with decreased conduction rate, motor response amplitude, and nerve sensation. The incidence of nerve damage was highest in the right peroneal nerve and left peroneal nerve (86.7% for both), followed by the right tibial nerve and left tibial nerve (67.2% and 68.9%, respectively). No significant differences were found in the rate of nerve defects between different age groups, body mass index (BMI) groups, or groups with hypertension or dyslipidemia. However, a statistically significant association was found between the rate of clinical neurological abnormalities and the duration of diabetes (p < 0.05). Patients with poor glucose control and/or decreased renal function also had a higher incidence of nerve defects. The study highlights the high incidence of peripheral neuropathy among T2DM patients in Vietnam and the association between nerve conduction abnormalities and poor glucose control and/or decreased renal function. The findings underscore the importance of early diagnosis and management of neuropathy in T2DM patients to prevent serious complications.

mTORC1 syndrome (TorS): unified paradigm for diabetes/metabolic syndrome

'Glucolipotoxicity' and 'insulin resistance' are claimed to drive type 2 diabetes (T2D) and the non-glycemic diseases of the metabolic syndrome (MetS) (obesity, dyslipidemia, hypertension). In line with that, glycemic and/or insulin control are considered to be primary goal in treating T2D/MetS. However, recent standard-of-care (SOC) treatments of T2D, initially designed to control T2D hyperglycemia, appear now to alleviate the cardio-renal and non-glycemic diseases of T2D/MetS independently of glucose lowering and insulin resistance, and in non-T2D patients altogether, calling for an alternative unifying pathophysiology/treatment paradigm for T2D/MetS. This opinion article proposes to replace the current 'glucolipotoxic/insulin-resistance' paradigm of T2D/MetS with an 'mammalian target of rapamycin complex 1 (mTORC1) syndrome' (TorS) paradigm, implying an exhaustive cohesive disease entity driven by an upstream hyperactive mTORC1, and which includes diabetic hyperglycemia, diabetic dyslipidemia, hypertension, diabetic macrovascular and microvascular disease, non-alcoholic fatty liver disease, some cancers, neurodegeneration, polycystic ovary syndrome (PCOS), psoriasis, and others. The TorS paradigm may account for the insulin-resistant glycemic context of TorS, combined with response to insulin of the non-glycemic diseases of TorS. The TorS paradigm may account for the efficacy of current antidiabetic SOC treatments in diabetic and nondiabetic patients. Most importantly, the TorS paradigm may generate novel treatments for TorS.

The relationship between vascular endothelial growth factor-A serum level and the severity of diabetic peripheral neuropathy

Background and aims

Diabetic peripheral neuropathy (DPN) is a common microvascular complication in type 2 diabetes mellitus (T2DM). The nerve fibers injury is caused by the interaction between metabolic and vascular factors. Vascular endothelial growth factor (VEGF) is an essential growth factor for vascular endothelial cells. We aimed to investigate the relation between VEGF-A serum level and the degree of DPN.

Results

This cross-sectional study was conducted on 81 patients with T2DM. Based on the combined clinical and electrophysiological assessment, 67 patients (82.7%) were diagnosed with peripheral neuropathy of which 32 patients (39.5%) had subclinical neuropathy, whereas 35 patients (43.2%) were confirmed cases of DPN. Patients with DPN had longer duration of DM and higher values of glycosylated hemoglobin (HbA1c). Although the mean serum VEGF-A level in diabetic patients without neuropathy was higher than that in diabetic patients with DPN, this difference did not reach statistical significance (P = 0.07). However, patients with subclinical DPN had significantly higher serum VEGF-A level compared to patients with confirmed DPN (P < 0.001).

Conclusion

DPN was found to be a common finding in the studied sample of T2DM patients. Longer duration of DM and poor glycemic control may be risk factors for development of severe DPN. Low VEGF-A serum levels may lead to more severe DPN in patients with T2DM.

Quantitative shear wave elastography assessment of tibial nerve in diagnosis of diabetic peripheral neuropathy

Background

Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes mellitus. Diagnosis of DPN is very important in the prognosis of disease and treatment as early treatment of DPN decreases both short-term and long-term morbidities. SWE elastography is a noninvasive and reproducible method for the precise evaluation of nerve stiffness.

Results

Tibial nerve stiffness is notably high at SWE in diabetic patients with DPN (mean shear wave elastography value of RT tibial SWE 75.3 ± 15.1 kPa) compared to patients without DPN (mean shear wave elastography value of RT tibial SWE 37.8 ± 11.6 kPa) and nerve stiffness in healthy control subjects (mean shear wave elastography value of RT tibial SWE 24.9 ± 6.3 kPa). There is a significant increase in the cross-sectional area (CSA) among diabetic patients with DPN (mean cross-sectional area of the right tibial nerve of 17 ± 1.9 mm2) and without DPN (mean cross-sectional area of the right tibial nerve of 14.5 ± 3.8 mm2) in comparison with control subjects (mean cross-sectional area of the right tibial nerve of 13.2 ± 3.1 mm2) in the right side. Borderline significance of the CSA parameters of the tibial nerve study on the left side in different groups. The cutoff point to determine DPN among diabetic patients in the right lower limb is more than 63.8 kPa. With 89% sensitivity and 100% specificity in the detection of DPN on the right side, the SWE has 100% PPV and 95.5% NPV in the detection of DPN on the right side.

Conclusion

SWE is an effective assistant method in the diagnosis of DPN and is useful when a suspected neuropathy is not detectable by electrophysiology.

Artificial intelligence based prediction models for individuals at risk of multiple diabetic complications: A systematic review of the literature

AIM

The aim of this review is to examine the effectiveness of artificial intelligence in predicting multimorbid diabetes-related complications.

BACKGROUND

In diabetic patients, several complications are often present, which have a significant impact on the quality of life; therefore, it is crucial to predict the level of risk for diabetes and its complications.

EVALUATION

International databases PubMed, CINAHL, MEDLINE and Scopus were searched using the terms artificial intelligence, diabetes mellitus and prediction of complications to identify studies on the effectiveness of artificial intelligence for predicting multimorbid diabetes-related complications. The results were organized by outcomes to allow more efficient comparison.

KEY ISSUES

Based on the inclusion/exclusion criteria, 11 articles were included in the final analysis. The most frequently predicted complications were diabetic neuropathy (n = 7). Authors included from two to a maximum of 14 complications. The most commonly used prediction models were penalized regression, random forest and Naïve Bayes model neural network.

CONCLUSION

The use of artificial intelligence can predict the risks of diabetes complications with greater precision based on available multidimensional datasets and provides an important tool for nurses working in preventive health care.

IMPLICATIONS FOR NURSING MANAGEMENT

Using artificial intelligence contributes to a better quality of care, better autonomy of patients in diabetes management and reduction of complications, costs of medical care and mortality.

A randomized controlled trial assessing the safety and efficacy of palmitoylethanolamide for treating diabetic-related peripheral neuropathic pain

Background

Peripheral neuropathy is a common complication of diabetes. The management of the associated neuropathic pain remains difficult to treat.

Objective

This study explored the safety, tolerability and efficacy of a palmitoylethanolamide (PEA) formulation in treating diabetic-related peripheral neuropathic pain (PNP). Secondary outcomes included systemic inflammation, sleep and mood changes in patients diagnosed with type 1 and type 2 diabetes and PNP.

Design

This study was a single-centre, quadruple-blinded, placebo-controlled trial with 70 participants receiving 600 mg of PEA or placebo daily, for 8 weeks, with a 94% rate of study participation completion. Primary outcomes were neuropathic pain and specific pain types (the BPI-DPN and NPSI). The secondary outcomes were sleep quality (MOS sleep scale), mood (DASS-21), glucose metabolism and inflammation.

Results

There was a significant reduction (P ≤ 0.001) in BPI-DPN total pain and pain interference, NPSI total score and sub-scores, except for evoked pain (P = 0.09) in the PEA group compared with the placebo group. The MOS sleep problem index and sub-scores significantly improved (P ≤ 0.001). DASS-21 depression scores significantly reduced (P = 0.03), but not anxiety or stress scores. Interleukin-6 and elevated C-reactive protein levels significantly reduced in the PEA group (P = 0.05), with no differences in fibrinogen between groups (P = 0.78) at treatment completion. There were no changes in safety pathology parameters, and the treatment was well tolerated.

Conclusions

The study demonstrated that the PEA formulation reduced diabetic peripheral neuropathic pain and inflammation along with improving mood and sleep. Further studies on the mechanistic effectiveness of PEA as an adjunct medicine and as a monotherapy pain analgesic are warranted.

Clinical Trial Registration

Registry name: Australian New Zealand Clinical Trials Registry (ANZCTR), Registration number: ACTRN12620001302943, Registration link: https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=380826, Actual study start date: 20 November 2020.

Interplay between exosomes and autophagy machinery in pain management: State of the art

Despite recent progress regarding inexpensive medical approaches, many individuals suffer from moderate to severe pain globally. The discovery and advent of exosomes, as biological nano-sized vesicles, has revolutionized current knowledge about underlying mechanisms associated with several pathological conditions. Indeed, these particles are touted as biological bio-shuttles with the potential to carry specific signaling biomolecules to cells in proximity and remote sites, maintaining cell-to-cell communication in a paracrine manner. A piece of evidence points to an intricate relationship between exosome biogenesis and autophagy signaling pathways at different molecular levels. A close collaboration of autophagic response with exosome release can affect the body's hemostasis and physiology of different cell types. This review is a preliminary attempt to highlight the possible interface of autophagy flux and exosome biogenesis on pain management with a special focus on neuropathic pain. It is thought that this review article will help us to understand the interplay of autophagic response and exosome biogenesis in the management of pain under pathological conditions. The application of therapies targeting autophagy pathway and exosome abscission can be an alternative strategy in the regulation of pain.

Sleep impairment: Is it an overlooked burden in painful diabetic peripheral neuropathy? A single-centre, cross-sectional study from south India

BACKGROUND AND AIMS

Painful diabetic peripheral neuropathy (PDPN) is a common complication of type 2 diabetes. The unrelenting pain associated with PDPN adversely affects a patient's quality of life. Recognizing the crucial role that sleep plays in the metabolic control of diabetes, this study aims to estimate the prevalence of sleep impairment in painful diabetic peripheral neuropathy (PDPN) and identify the factors associated with it.

METHODS

We conducted a cross-sectional study among 156 patients in a tertiary care hospital in south India. We recruited consenting adults with PDPN. Sleep quality was analyzed using the Pittsburg sleep quality index (PSQI), a self-rating scale. Hba1c served as a measure of glycemic control. Anxiety and depression were assessed using the hospital anxiety and depression (HAD) scale. Data were analyzed in SPSS 26.0.

RESULTS

A total of 156 patients were included in the study with a mean age of 58.39 ± 9.12 years. In 151 (96.79%) patients demonstrated sleep impairment with a global PSQI score of 10.92 ± 2.87. Female sex, ischemic heart disease (IHD), high anxiety levels and use of insulin, pregabapentin, and duloxetine; were significantly associated with poor sleep quality (p < 0.05). The median Hba1c was high (9% [7.46-11.1]). However, there was no statistical correlation between the degree of sleep impairment and glycemic control.

CONCLUSION

We found a high prevalence of sleep impairment in patients with PDPN. Female sex, IHD, high anxiety levels and use of neuropathic drugs were predictors of poor sleep quality.

Potentiation of morphine antinociception and inhibition of diabetic neuropathic pain by the multi-chemokine receptor antagonist peptide RAP-103

AIMS

We determined the ability of the multi-chemokine receptor (CCR2/CCR5/CCR8) antagonist RAP-103 to modulate pain behaviors in an acute model of surgical pain, with and without an added opioid (morphine), and by itself in a chronic model of Streptozotocin (STZ)-induced diabetic peripheral neuropathy (DPN).

MATERIALS AND METHODS

Pain behaviors were assessed by mechanical and thermal tests in rats. Cytokine and chemokine biomarkers in sciatic nerve and spinal cord were assessed by in situ qPCR.

KEY FINDINGS

In the incisional pain assay, RAP-103 (0.01-1 mg/kg, i.p.) alone had no antiallodynic effect post-surgery. RAP-103 (0.5 mg/kg) when co-administered with morphine (0.5-5 mg/kg), reduced the ED₅₀ of morphine from 3.19 mg/kg to 1.42 mg/kg. In a DPN model, rats exhibited persistent mechanical and cold allodynia. Oral administration of RAP-103 (0.5-0.02 mg/kg/day) resulted in a complete reversal of established hypersensitivity in DPN rats (P < .001), which gradually returned to pain hypersensitivity after the cessation of the treatment. The mRNA expression of cytokines, IL-1β, TNFα; chemokines CCL2, CCL3; and chemokine receptors CCR2 and CCR5 in DPN rat sciatic nerve, but not spinal cord, were significantly increased. RAP-103 resulted in significant reductions in sciatic nerve expression of IL-1β, TNFα and CCL3 in STZ-induced diabetic rats with trends toward lower levels for CCL2 and CCR5, while CCR2 was unchanged.

SIGNIFICANCE

In acute pain, co-administration of RAP-103 with morphine provided the same antinociceptive effect with a reduced dose of morphine, reducing opioid side-effects and risks. RAP-103 by itself is an effective non-opioid antinociceptive treatment for diabetic neuropathic pain.

Clinical and neurophysiological characterization of early neuromuscular involvement in children and adolescents with nephropathic cystinosis

BACKGROUND

Nephropathic cystinosis is a rare autosomal recessive lysosomal storage disorder characterized by kidney and extra-renal complications due to the accumulation of cystine crystals in various tissues and organs. Herein, we describe the early neuromuscular complications in a cohort of pediatric nephropathic cystinosis patients.

METHODS

We prospectively evaluated the clinical, biochemical, and neurophysiological data of 15 cystinosis patients. Neurophysiological evaluation was performed to confirm or exclude presence of neuropathy and/or myopathy.

RESULTS

Patients' age ranged between 20 and 216 months at time of examination. Nine patients were males. Three patients had early abnormal neurophysiological features consistent with neuromuscular involvement (clinically asymptomatic proximal myopathy with a patchy distribution in one patient and isolated asymptomatic sensory nerve conduction changes in two patients). A fourth patient had mixed abnormal motor and sensory axonal neuropathic changes associated with overt clinical features (predominantly motor symptoms). Patients with abnormal neuromuscular features were significantly older in age than the unaffected group (P = 0.005) and had a diagnosis of cystinosis with subsequent cysteamine therapy at a significantly older age than the unaffected group (P = 0.027 and 0.001, respectively).

CONCLUSIONS

We expanded the recognized phenotypes of cystinosis neuromuscular complications with early proximal skeletal myopathy and symptomatic motor and sensory axonal neuropathy. Early asymptomatic neuromuscular complications could develop in pediatric patients and would require neurophysiological studies for early detection prior to development of overt clinical manifestations. Prompt diagnosis and timely initiation of cysteamine therapy with recommended dose can delay the development of neuromuscular complications. A higher resolution version of the Graphical abstract is available as Supplementary information.

Isolation of Thymol from Trachyspermum ammi Fruits for Treatment of Diabetes and Diabetic Neuropathy in STZ-Induced Rats

Terpenoids and phenols from Trachyspermum ammi (T. ammi) have reported some pharmacological actions. The objective of the work was to isolate the active constituent, its identification by spectroscopic techniques, and evaluation of the antidiabetic and neuroprotective activity from T. ammi on STZ Wistar rats. The dried fruits of T ammi were kept in a hydrodistillation apparatus to collect essential oil. The isolated fraction went through TLC, UV, FTIR, HPLC, HRMS, C¹³, and ¹H NMR for characterization. Two dosage concentrations from the isolated compound were prepared as 10 and 20 mg/kg for treatment groups. The groups were tested for thermal and mechanical hyperalgesia, writhing, grip strength, spontaneous locomotor test, neuromuscular coordination tests, and histopathological and lipid profile analysis. Diabetes was induced by streptozotocin (45 mg/kg i.p.) and 12 weeks of treatment-induced diabetic neuropathy in Wistar rats. Biomarkers were evaluated to understand the neuropathic protection of thymol on STZ-treated Wistar rats. The biomarker studies (SOD, NO, LPO, Na⁺K⁺ATPase, and TNF-α) further confirmed thymol's diabetic neuropathy protective action. This study suggests that isolated compound thymol was antidiabetic and neuroprotective as it has shown controlled glucose levels defensive nerve damage in STZ Wistar rats. P < 0.05 level of significance was observed in the levels of endogenous biomarkers, fasting blood glucose levels, actophotometer response, and response latency in treated groups compared to the diabetic group, whereas P < 0.001 level of significance during lipid profile levels, thermal algesia, and neuromuscular comparison tests was noted in treated groups compared to the diabetic group.

Mechanistic insights on burdock (Arctium lappa L.) extract effects on diabetes mellitus

Diabetes mellitus (DM) type 2 is amongst the most common chronic diseases, being responsible for various problems in humans and contributing to increased mortality rates worldwide. Fructooligosaccharide, which can be produced from the roots of burdock (Arctium lappa L.), has been shown to have a wide range of pharmacological proprieties, including antiviral, anti-inflammatory, hypolipidemic, and antidiabetic effects. Moreover, burdock also contains chlorogenic acid, which has been used in traditional medicine as an antioxidant. Considering its natural origin and minimal toxicity, burdock fructooligosaccharides (BFO) has gained considerable attention from researchers owing its wide, efficient, and beneficial action against DM. Although the effectiveness of fructooligosaccharide and chlorogenic acid has been extensively discussed, limited information is available on the application of burdock for DM treatment. In this review, we discuss the beneficial contributions, and the recent in vitro and in vivo analytical findings on A. lappa extract as DM therapy.

Clinical outcomes in 'diabese' burn patients: A systematic review and meta-analysis

OBJECTIVE

The objective of this study was to update the current status of clinical outcomes in diabetic (type II) and obese (BMI: 30-39.9 kg/m²) burn patients.

METHODS

We adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We searched MEDLINE (PubMed), Google Scholar, Scopus, and Embase for studies related to a number of comorbidities and burn outcomes. Search terms for each of these databases are listed in the Appendix. From this search, we screened 6923 articles. Through our selection criteria, 12 articles focusing on either diabetes or obesity were selected for systematic review and meta-analysis. Data was analyzed using the "meta" package in R software to produce pooled odds ratios from the random effect model.

RESULTS

Diabetic patients had 2.38 times higher odds of mortality [OR: 2.38, 95% CI:1.66, 3.41], however no statistically significant difference was found in mortality in obese patients [OR: 2.49, 95% CI: 0.36, 17.19]. Obese patients had 2.18 times higher odds of inhalation injury [95%CI: 1.23, 3.88], whereas diabetic patients did not show a difference in odds of inhalation injury [OR:1.02, 95% CI: 0.57, 1.81]. Diabetic patients had higher odds of complications resulting from infection: 5.47 times higher odds of wound, skin, or soft tissue infections [95% CI:1.97, 15.18]; 2.28 times higher odds of UTI or CAUTI [95% CI:1.50, 3.46]; and 1.78 times higher odds of pneumonia or respiratory tract infections [95% CI:1.15, 2.77]. Obese patients also had similar complications related to infection: 2.15 times higher odds of wound infection [95% CI: 1.04, 4.42] and 1.96 times higher odds of pneumonia [95% CI: 1.08, 3.56]. Other notable complications in diabetic patients were higher odds of amputation [OR: 37, 95% CI: 1.76, 779.34], respiratory failure [OR: 4.39, 95% CI: 1.85, 10.42], heart failure [OR: 6.22, 95% CI: 1.93, 20.06], and renal failure [OR: 2.95, 95% CI: 1.1, 7.86].

CONCLUSIONS

Diabetic patients have higher odds of mortality, whereas no statistically significant difference of mortality was found in obese patients. Obese patients had higher odds of inhalation injury, whereas odds of inhalation injury was unchanged in diabetic patients. Diabetic patients had higher odds of failure in multiple organs, whereas such failure in obese patients was not reported. Both diabetic and obese patients had multiple complications related to infection.

Advances in Interventional Therapies for Painful Diabetic Neuropathy: A Systematic Review

BACKGROUND

Painful diabetic neuropathy (PDN) is one of the major complications of diabetes mellitus. It is often debilitating and refractory to pharmaceutical therapies. Our goal was to systematically review and evaluate the strength of evidence of interventional management options for PDN and make evidence-based recommendations for clinical practice.

METHODS

We searched PubMed, Scopus, Google Scholar, and Cochrane Llibrary and systematically reviewed all types of clinical studies on interventional management modalities for PDN.

RESULTS

We identified and analyzed 10 relevant randomized clinical trials (RCTs), 8 systematic reviews/meta-analyses, and 5 observational studies of interventional modalities for PDN using pain as primary outcome. We assessed the risk of bias in grading of evidence and found that there is moderate to strong evidence to support the use of dorsal column spinal cord stimulation (SCS) in treating PDN in the lower extremities (evidence level: 1B+), while studies investigating its efficacy in the upper extremities are lacking. Evidence exists that acupuncture and injection of botulinum toxin-A provide relief in pain or muscle cramps due to PDN with minimal side effects (2B+/1B+). Similar level of evidence supports surgical decompression of lower limb peripheral nerves in patients with intractable PDN and superimposed nerve compression (2B±/1B+). Evidence for sympathetic blocks or neurolysis and dorsal root ganglion (DRG) stimulation is limited to case series (2C+).

CONCLUSIONS

Moderate to strong evidence exists to support the use of SCS in managing lower extremity pain in patients who have failed conventional medical management for PDN. Acupuncture or injection of botulinum toxin-A can be considered as an adjunctive therapy for PDN. Surgical decompression of peripheral nerves may be considered in patients with PDN superimposed with nerve compression. High-quality studies are warranted to further evaluate the safety, efficacy, and cost-effectiveness of interventional therapies for PDN.

Genetic Variants and Their Associations to Type 2 Diabetes Mellitus Complications in the United Arab Emirates

Aim

Type 2 Diabetes Mellitus (T2DM) is associated with microvascular complications, including diabetic retinopathy (DR), diabetic nephropathy (DNp), and diabetic peripheral neuropathy (DPN). In this study, we investigated genetic variations and Single Nucleotide Polymorphisms (SNPs) associated with DR, DNp, DPN and their combinations among T2DM patients of Arab origin from the United Arab Emirates, to establish the role of genes in the progression of microvascular diabetes complications.

Methods

A total of 158 Emirati patients with T2DM were recruited in this study. The study population was divided into 8 groups based on the presence of single, dual, or all three complications. SNPs were selected for association analyses through a search of publicly available databases, specifically genome-wide association study (GWAS) catalog, infinome genome interpretation platform, and GWAS Central database. A multivariate logistic regression analysis and association test were performed to evaluate the association between 83 SNPs and DR, DNp, DPN, and their combinations.

Results

Eighty-three SNPs were identified as being associated with T2DM and 18 SNPs had significant associations to one or more diabetes complications. The most strongly significant association for DR was rs3024997 SNP in the VEGFA gene. The top-ranked SNP for DPN was rs4496877 in the NOS3 gene. A trend towards association was detected at rs833068 and rs3024998 in the VEGFA gene with DR and rs743507 and rs1808593 in the NOS3 gene with DNp. For dual complications, the rs833061, rs833068 and rs3024997 in the VEGFA gene and the rs4149263 SNP in the ABCA1 gene were also with borderline association with DR/DNp and DPN/DNp, respectively. Diabetic with all of the complications was significantly associated with rs2230806 in the ABCA1 gene. In addition, the highly associated SNPs rs3024997 of the VEGFA gene and rs4496877 of the NOS3 gene were linked to DR and DPN after adjusting for the effects of other associated markers, respectively.

Conclusions

The present study reports associations of different genetic polymorphisms with microvascular complications and their combinations in Emirati T2DM patients, reporting new associations, and corroborating previous findings. Of interest is that some SNPs/genes were only present if multiple comorbidities were present and not associated with any single complication.

Prevalence and Clinical Significance of Subclinical Hypothyroidism in Diabetic Peripheral Neuropathy

Background and Aim

Diabetic peripheral neuropathy (DPN) is one of the most common and disabling complications of DM. Many studies documented the prevalence of clinical and subclinical hypothyroidism (SCH) in diabetic patients but not in the particular group of patients with DPN. The present study aimed to determine the prevalence of SCH in DPN patients and to evaluate its association with severity of DPN.

Patients and Methods

The present cross-sectional study was conducted on 300 consecutive patients with DPN. The clinical manifestations of DPN were documented according to the validated Arabic version of the Michigan Neuropathy Screening Instrument. Severity of DPN was categorized into mild (6–8 points), moderate (9–11 points) or severe (12+ points) according to the Toronto Clinical Scoring System. All patients were submitted to careful history-taking and full clinical and neurological examination. Patients were diagnosed with SCH if they had TSH level above the upper limit of the normal reference range in association with normal free thyroxine (FT4) level.

Results

SCH was prevalent in 53 patients (17.7%, 95% CI: 13.5%–22.5%). Patients with SCH had significantly higher frequency of severe DPN (52.8% versus 28.3%, p=0.003). It was also shown that patients with SCH had significantly higher HbA1c (8.4 ± 1.0 versus 7.3 ± 1.2%, p<0.001) and HOMA-IR (3.7 ± 0.8 versus 2.7 ± 0.9, p<0.001) when compared with patients without SCH. Logistic regression analysis identified patients’ age [OR (95% CI): 1.06 (1.03–1.08), p<0.001], HbA1c [OR (95% CI): 2.2 (1.7–2.9), p<0.001] and SCH [OR (95% CI): 7.7 (3.6–15.5), p<0.001] as independent predictors of DPN severity.

Conclusion

The present study showed that SCH is highly prevalent in DPN patients and is independently related to its severity.

Inosine mitigated diabetic peripheral neuropathy via modulating GLO1/AGEs/RAGE/NF-κB/Nrf2 and TGF-β/PKC/TRPV1 signaling pathways

Inosine is a dietary supplement that is widely used for managing numerous central neurological disorders. Interestingly, recent experimental investigation of inosine revealed its potential to promote peripheral neuroprotection after sciatic nerve injury. Such investigation has guided the focus of the current study to expose the potential of inosine in mitigating diabetic peripheral neuropathy (DPN) in rats and to study the possible underlying signaling pathways. Adult male Wistar rats were arbitrarily distributed into four groups. In the first group, animals received saline daily for 15 days whereas rats of the remaining groups received a single injection of both nicotinamide (50 mg/Kg/i.p.) and streptozotocin (52.5 mg/Kg/i.p.) for DPN induction. Afterward, inosine (10 mg/Kg/p.o.) was administered to two groups, either alone or in combination with caffeine (3.75 mg/Kg/p.o.), an adenosine receptor antagonist. As a result, inosine showed a hypoglycemic effect, restored the sciatic nerve histological structure, enhanced myelination, modulated conduction velocities and maintained behavioral responses. Furthermore, inosine increased GLO1, reduced AGE/RAGE axis and oxidative stress which in turn, downregulated NF-κB p65 and its phosphorylated form in the sciatic nerves. Inosine enhanced Nrf2 expression and its downstream molecule HO-1, resulting in increased CAT and SOD along with lowered MDA. Moreover, pain was relieved due to suppression of PKC and TRPV1 expression, which ultimately lead to reduced SP and TGF-β. The potential effects of inosine were nearly blocked by caffeine administration; this emphasizes the role of adenosine receptors in inosine-mediated neuroprotective effects. In conclusion, inosine alleviated hyperglycemia-induced DPN via modulating GLO1/AGE/RAGE/NF-κB p65/Nrf2 and TGF-β/PKC/TRPV1/SP pathways.

FootAssure: A multimodal, in-home wound detection device for diabetic peripheral neuropathy

Currently, there is no single technology capable of assessing all the multitude of factors associated with peripheral complications of diabetic neuropathy. In this work, a multimodal wound detection system is proposed to help facilitate in-home examinations, utilizing a combination of thermal, multi-spectral 3D imaging modalities. The proposed system is capable of the 3D surface rendering of the foot and would overlay thermal, blood oxygenation, besides other skin health information to aid with foot health monitoring. Examples of biomarkers include pre-ulcer formation, blood circulation, temperature change, oxygenation, swelling, blisters/ulcer formation and healing, and toe health.

Exploring Nociceptive Detection Thresholds Combined with Evoked Potentials in Patients with Diabetes Mellitus

There is a lack of diagnostic tools that can objectively measure small fiber neuropathy (SFN) in patients with diabetes mellitus (DM). Recently, nociceptive nerve function was observed by nociceptive detection thresholds (NDTs) and brain evoked potentials (EPs) during intra-epidermal electrical stimulation (IES) targeting Aδ-fibers. In this proof of principle, we studied whether it is possible to measure NDTs combined with EPs in DM patients with and without neuropathic pain. Furthermore, we explored the sensitivity of NDTs and EPs for polyneuropathy in these patients. Five DM patients diagnosed with painful neuropathy (DMp), five DM patients without painful neuropathy (DM), and five healthy controls (HC) were analyzed. These preliminary results showed that we can accurately measure NDTs and EPs in patients with diabetes. Strikingly, increased NDTs were found in DM and DMp compared to HC, of which the DMp showed the largest NDTs. This suggests that NDTs during IES could be a powerful biomarker for monitoring peripheral dysfunctions. Current EEG data of patients did not show any significant differences. The population needs to be enlarged before we can investigate the sensitivity of these NDTs and EPs to diabetic polyneuropathy and associated changes in nociceptive processing in more detail.Clinical Relevance- This proof of principle in a small group of patients with diabetes mellitus potentially treats the observation of the loss of nociceptive function occurring with small fiber neuropathy. That helps the development of a diagnostic measure to monitor future (early-stage) nociceptive dysfunctions in a clinical environment.

Advances in diet-induced rodent models of metabolically acquired peripheral neuropathy

Peripheral neuropathy (PN) is a severe complication that affects over 30% of prediabetic and 60% of type 2 diabetic (T2D) patients. The metabolic syndrome is increasingly recognized as a major driver of PN. However, basic and translational research is needed to understand the mechanisms that contribute to nerve damage. Rodent models of diet-induced obesity, prediabetes, T2D and PN closely resemble the human disease and have proven to be instrumental for the study of PN mechanisms. In this Perspective article, we focus on the development, neurological characterization and dietary fat considerations of diet-induced rodent models of PN. We highlight the importance of investigating sex differences and discuss some of the challenges in translation from bench to bedside, including recapitulating the progressive nature of human PN and modeling neuropathic pain. We emphasize that future research should overcome these challenges in the quest to better mimic human PN in animal models.

Pathophysiology and Molecular Imaging of Diabetic Foot Infections

Diabetic foot infection is the leading cause of non-traumatic lower limb amputations worldwide. In addition, diabetes mellitus and sequela of the disease are increasing in prevalence. In 2017, 9.4% of Americans were diagnosed with diabetes mellitus (DM). The growing pervasiveness and financial implications of diabetic foot infection (DFI) indicate an acute need for improved clinical assessment and treatment. Complex pathophysiology and suboptimal specificity of current non-invasive imaging modalities have made diagnosis and treatment response challenging. Current anatomical and molecular clinical imaging strategies have mainly targeted the host's immune responses rather than the unique metabolism of the invading microorganism. Advances in imaging have the potential to reduce the impact of these problems and improve the assessment of DFI, particularly in distinguishing infection of soft tissue alone from osteomyelitis (OM). This review presents a summary of the known pathophysiology of DFI, the molecular basis of current and emerging diagnostic imaging techniques, and the mechanistic links of these imaging techniques to the pathophysiology of diabetic foot infections.

Pathophysiology and Molecular Imaging of Diabetic Foot Infections

Diabetic foot infection is the leading cause of non-traumatic lower limb amputations worldwide. In addition, diabetes mellitus and sequela of the disease are increasing in prevalence. In 2017, 9.4% of Americans were diagnosed with diabetes mellitus (DM). The growing pervasiveness and financial implications of diabetic foot infection (DFI) indicate an acute need for improved clinical assessment and treatment. Complex pathophysiology and suboptimal specificity of current non-invasive imaging modalities have made diagnosis and treatment response challenging. Current anatomical and molecular clinical imaging strategies have mainly targeted the host's immune responses rather than the unique metabolism of the invading microorganism. Advances in imaging have the potential to reduce the impact of these problems and improve the assessment of DFI, particularly in distinguishing infection of soft tissue alone from osteomyelitis (OM). This review presents a summary of the known pathophysiology of DFI, the molecular basis of current and emerging diagnostic imaging techniques, and the mechanistic links of these imaging techniques to the pathophysiology of diabetic foot infections.

Diagnosis of Muscle Fatigue Using Surface Electromyography and Analysis of Associated Factors in Type 2 Diabetic Patients with Neuropathy: A Preliminary Study

Diabetic neuropathy (DN) is a major complication associated with diabetes mellitus (DM) and results in fatigue. We investigated whether type 2 diabetic patients with or without neuropathy experienced muscle fatigue and determined the most influencing factor on muscle fatigue. Overall, 15 out of 25 patients with type 2 DM were diagnosed with DN using a nerve conduction study in the upper and lower extremities, and the composite score (CS) was calculated. We obtained the duration of DM and body mass index (BMI) from subjects, and they underwent a series of laboratory tests including HbA1c, fasting plasma glucose, triglycerides, and high- and low-density lipoprotein. To qualify muscle fatigue, this study used surface electromyography (sEMG). Anode and cathode electrodes were attached to the medial gastrocnemius. After 100% isometric maximal voluntary contracture of plantarflexion, the root mean square, median frequency (MDF), and mean power frequency (MNF) were obtained. We showed a correlation among laboratory results, duration of DM, BMI, CS, and parameters of muscle fatigue. The duration of DM was related to fatigue of the muscle and CS (p < 0.05). However, CS was not related to fatigue. The MDF and MNF of muscle parameters were positively correlated with HbA1c and fasting plasma glucose (p < 0.05). In conclusion, we suggest that the duration of DM and glycemic control play important roles in muscle fatigue in patients with DN. Additionally, sEMG is useful for diagnosing muscle fatigue in patients with DN.

Increasing Angiogenesis Factors in Hypoxic Diabetic Wound Conditions by siRNA Delivery: Additive Effect of LbL-Gold Nanocarriers and Desloratadine-Induced Lysosomal Escape

Impaired wound healing in people with diabetes has multifactorial causes, with insufficient neovascularization being one of the most important. Hypoxia-inducible factor-1 (HIF-1) plays a central role in the hypoxia-induced response by activating angiogenesis factors. As its activity is under precise regulatory control of prolyl-hydroxylase domain 2 (PHD-2), downregulation of PHD-2 by small interfering RNA (siRNA) could stabilize HIF-1α and, therefore, upregulate the expression of pro-angiogenic factors as well. Intracellular delivery of siRNA can be achieved with nanocarriers that must fulfill several requirements, including high stability, low toxicity, and high transfection efficiency. Here, we designed and compared the performance of layer-by-layer self-assembled siRNA-loaded gold nanoparticles with two different outer layers-Chitosan (AuNP@CS) and Poly L-arginine (AuNP@PLA). Although both formulations have exactly the same core, we find that a PLA outer layer improves the endosomal escape of siRNA, and therefore, transfection efficiency, after endocytic uptake in NIH-3T3 cells. Furthermore, we found that endosomal escape of AuNP@PLA could be improved further when cells were additionally treated with desloratadine, thus outperforming commercial reagents such as Lipofectamine® and jetPRIME®. AuNP@PLA in combination with desloratadine was proven to induce PHD-2 silencing in fibroblasts, allowing upregulation of pro-angiogenic pathways. This finding in an in vitro context constitutes a first step towards improving diabetic wound healing with siRNA therapy.

Peripheral Neuropathy: Comparison of Symptoms and Severity Between Colorectal Cancer Survivors and Patients With Diabetes

BACKGROUND

Peripheral neuropathy (PN) is a common symptom in colorectal cancer (CRC) survivors and patients with diabetes. However, the differences in PN symptoms between CRC survivors and patients with diabetes are not clear.

OBJECTIVES

The purpose of this study was to examine the differences in PN between CRC survivors and patients with diabetes.

METHODS

Secondary data were analyzed from two cross-sectional studies consisting of 81 CRC survivors and 86 patients with diabetes from two hospitals in northern and central Taiwan. Data were analyzed using descriptive statistics, analysis of covariance, and multiple logistic regression.

FINDINGS

Significant differences in severity and prevalence of PN and neuropathic pain between CRC survivors and patients with diabetes were found. Patients with diabetes had significantly more severe PN and sensory PN compared to CRC survivors. In addition, the prevalence of PN and neuropathic pain was significantly higher in CRC survivors compared to patients with diabetes after control of covariates.

Gene expression profiles of diabetic kidney disease and neuropathy in eNOS knockout mice: Predictors of pathology and RAS blockade effects

Diabetic kidney disease (DKD) and diabetic peripheral neuropathy (DPN) are two common diabetic complications. However, their pathogenesis remains elusive and current therapies are only modestly effective. We evaluated genome-wide expression to identify pathways involved in DKD and DPN progression in db/db eNOS-/- mice receiving renin-angiotensin-aldosterone system (RAS)-blocking drugs to mimic the current standard of care for DKD patients. Diabetes and eNOS deletion worsened DKD, which improved with RAS treatment. Diabetes also induced DPN, which was not affected by eNOS deletion or RAS blockade. Given the multiple factors affecting DKD and the graded differences in disease severity across mouse groups, an automatic data analysis method, SOM, or self-organizing map was used to elucidate glomerular transcriptional changes associated with DKD, whereas pairwise bioinformatic analysis was used for DPN. These analyses revealed that enhanced gene expression in several pro-inflammatory networks and reduced expression of development genes correlated with worsening DKD. Although RAS treatment ameliorated the nephropathy phenotype, it did not alter the more abnormal gene expression changes in kidney. Moreover, RAS exacerbated expression of genes related to inflammation and oxidant generation in peripheral nerves. The graded increase in inflammatory gene expression and decrease in development gene expression with DKD progression underline the potentially important role of these pathways in DKD pathogenesis. Since RAS blockers worsened this gene expression pattern in both DKD and DPN, it may partly explain the inadequate therapeutic efficacy of such blockers.

The increase of neuropathic symptoms in diabetic patients is related with osteopenia

PURPOSE

To investigate the relationship between the intensity of neuropathic pain and the severity of osteopenia in type 2 diabetic patients with painful diabetic peripheral neuropathy (painful DPN).

METHODS

In 220 patients with type 2 diabetes included in the screening, the presence of neuropathic pain was evaluated using the Douleur Neuropathique 4 Questions (DN4) scoring system. One hundred forty-five patients with painful DPN were identified and included in the study. Socio-demographic and laboratory evaluations were made and bone mineral density (BMD) of these patients was evaluated by the dual-energy x-ray absorptiometry (DEXA) method.

RESULTS

There was a significant correlation between the neuropathic pain score and the total T scores of the lumbar spine and femur in patients with painful DPN. According to the regression analysis (standard coefficients), the DN4 score (0.498); the level of vitamin D (- 0.246) and the female sex (0.236) for the lumbar spine region; age (0.387); DN4 score (0.261); and vitamin D level (- 0.155) for the femur region were independently influencing factors on the development of osteoporosis. When osteoporosis (T score ≤ - 2.5) of the lumbar spine was analyzed by binary logistic regression, the risk of osteoporosis in women was 4.4 times higher, and the risk increased with increasing DN4 score.

CONCLUSION

The increase of neuropathic symptoms in patients with DPN is an effective and important factor in the development of diabetic osteopenia.

Vitamin D and rosuvastatin obliterate peripheral neuropathy in a type-2 diabetes model through modulating Notch1, Wnt-10α, TGF-β and NRF-1 crosstalk

AIMS

Vitamin D and rosuvastatin are well-known drugs that mediate beneficial effects in treating type-2 diabetes (T2D) complications; however, their anti-neuropathic potential is debatable. Hence, our study investigates their neurotherapeutic potential and the possible underlying mechanisms using a T2D-associated neuropathy rat model.

MAIN METHODS

Diabetic peripheral neuropathy (DPN) was induced with 8 weeks of administration of a high fat fructose diet followed by a single i.p. injection of streptozotocin (35 mg/kg). Six weeks later, DPN developed and rats were divided into five groups; viz., control, untreated DPN, DPN treated with vitamin D (cholecalciferol, 3500 IU/kg/week), DPN treated with rosuvastatin (10 mg/kg/day), or DPN treated with combination vitamin D and rosuvastatin. We determined their anti-neuropathic effects on small nerves (tail flick test); large nerves (electrophysiological and histological examination); neuronal inflammation (TNF-α and IL-18); apoptosis (caspase-3 activity and Bcl-2); mitochondrial function (NRF-1, TFAM, mtDNA, and ATP); and NICD1, Wnt-10α/β-catenin, and TGF-β/Smad-7 pathways.

KEY FINDINGS

Two-month treatment with vitamin D and/or rosuvastatin regenerated neuronal function and architecture and abated neuronal inflammation and apoptosis. This was verified by the inhibition of the neuronal content of TNF-α, IL-18, and caspase-3 activity, while augmenting Bcl-2 content in the sciatic nerve. These treatments inhibited the protein expressions of NICD1, Wnt-10α, β-catenin, and TGF-β; increased the sciatic nerve content of Smad-7; and enhanced mitochondrial biogenesis and function.

SIGNIFICANCE

Vitamin D and/or rosuvastatin alleviated diabetes-induced neuropathy by suppressing Notch1 and Wnt-10α/β-catenin; modulating TGF-β/Smad-7 signaling pathways; and enhancing mitochondrial function, which lessened neuronal degeneration, demyelination, and fibrosis.

Deciphering the Neuroprotective Role of Glucagon-like Peptide-1 Agonists in Diabetic Neuropathy: Current Perspective and Future Directions

Diabetic neuropathy is referred to as a subsequential and debilitating complication belonging to type 1 and type 2 diabetes mellitus. It is a heterogeneous group of disorders with a particularly complex pathophysiology and also includes multiple forms, ranging from normal discomfort to death. The evaluation of diabetic neuropathy is associated with hyperglycemic responses, resulting in an alteration in various metabolic pathways, including protein kinase C pathway, polyol pathway and hexosamine pathway in Schwann and glial cells of neurons. The essential source of neuronal destruction is analogous to these respective metabolic pathways, thus identified as potential therapeutic targets. These pathways regulating therapeutic medications may be used for diabetic neuropathy, however, only target specific drugs could have partial therapeutic activity. Various antidiabetic medications have been approved and marketed, which possess the therapeutic ability to control hyperglycemia and ameliorate the prevalence of diabetic neuropathy. Among all antidiabetic medications, incretin therapy, including Glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors, are the most favorable medications for the management of diabetes mellitus and associated peripheral neuropathic complications. Besides enhancing glucose-evoked insulin release from pancreatic β-cells, these therapeutic agents also play a vital role to facilitate neurite outgrowth and nerve conduction velocity in dorsal root ganglion. Furthermore, incretin therapy also activates cAMP and ERK signalling pathways, resulting in nerve regeneration and repairing. These effects are evidently supported by a series of preclinical data and investigations associated with these medications. However, the literature lacks adequate clinical trial outcomes related to these novel antidiabetic medications. The manuscript emphasizes the pathogenesis, current pharmacological approaches and vivid description of preclinical and clinical data for the effective management of diabetic neuropathy.

Prevalence and incidence of diabetic peripheral neuropathy in Latin America and the Caribbean: A systematic review and meta-analysis

AIMS

The objective of this systematic review and meta-analysis is to estimate the prevalence and incidence of diabetic peripheral neuropathy (DPN) in Latin America and the Caribbean (LAC).

MATERIALS AND METHODS

We searched MEDLINE, SCOPUS, Web of Science, EMBASE and LILACS databases of published observational studies in LAC up to December 2020. Meta-analyses of proportions were performed using random-effects models using Stata Program 15.1. Heterogeneity was evaluated through sensitivity, subgroup, and meta-regression analyses. Evidence certainty was performed with the GRADE approach.

RESULTS

Twenty-nine studies from eight countries were included. The estimated prevalence of DPN was 46.5% (95%CI: 38.0-55.0) with a significant heterogeneity (I2 = 98.2%; p<0.01). Only two studies reported incidence, and the pooled effect size was 13.7% (95%CI: 10.6-17.2). We found an increasing trend of cumulative DPN prevalence over time. The main sources of heterogeneity associated with higher prevalence were diagnosis criteria, higher A1c (%), and inadequate sample size. We judge the included evidence as very low certainty.

CONCLUSION

The overall prevalence of DPN is high in LAC with significant heterogeneity between and within countries that could be explained by population type and methodological aspects. Significant gaps (e.g., under-representation of most countries, lack of incidence studies, and heterogenous case definition) were identified. Standardized and population-based studies of DPN in LAC are needed.