Epidemiological correlates of diabetic neuropathy. Report from Pittsburgh Epidemiology of Diabetes Complications Study

Exploring auditory temporal resolution and dichotic listening skills among individuals with type 2 diabetes mellitus

The study aimed to explore the auditory temporal resolution and dichotic listening skills in patients with type 2 diabetes mellitus (T2DM) and identify associated health-related factors. Using a cross-sectional design, 87 adults with T2DM and 48 non-diabetic controls, all with normal hearing, participated. The two central auditory processing (CAP) skills were assessed through the Gaps-In-Noise (GIN) and Dichotic-Digits Listening (DDL) tests. T2DM participants underwent blood tests to measure various health-related factors. In the GIN test, the shortest gap threshold (GapTh) obtained across both ears was significantly higher in the diabetic group (9.1 ± 2.4 ms) compared to the non-diabetic group (7.5 ± 1.5 ms), and the score of correctly identified gaps (GapSc) in the diabetic group (45±11 %) was significantly lower than GapSc in the non-diabetic group (52±9 %), p < 0.001. In the DDL test, the free-recall score (73.8 ± 18.5 %) across both ears and the right-ear advantage (-1.3 ± 20.6 %) in the diabetic group were significantly lower than the free-recall score (85.8 ± 11.9 %) and right-ear advantage (6.9 ± 11.9 %) in the non-diabetic group, p < 0.005. Furthermore, the duration of diabetes, eGFR level, retinopathy, carotid plaque, fasting blood glucose level, and HDL-C (good cholesterol) level were factors significantly associated with performances in the GIN and/or DDL tests for T2DM participants. In conclusion, individuals with T2DM are at risk of reduced auditory processing skills in temporal resolution and dichotic listening, impacting their speech understanding. Six health-related factors were identified as significantly associated with CAP skills in T2DM patients.

Unraveling the epigenetic fabric of type 2 diabetes mellitus: pathogenic mechanisms and therapeutic implications

Type 2 diabetes mellitus (T2DM) is a rapidly escalating global health concern, with its prevalence projected to increase significantly in the near future. This review delves into the intricate role of epigenetic modifications - including DNA methylation, histone acetylation, and micro-ribonucleic acid (miRNA) expression - in the pathogenesis and progression of T2DM. We critically examine how these epigenetic changes contribute to the onset and exacerbation of T2DM by influencing key pathogenic processes such as obesity, insulin resistance, β-cell dysfunction, cellular senescence, and mitochondrial dysfunction. Furthermore, we explore the involvement of epigenetic dysregulation in T2DM-associated complications, including diabetic retinopathy, atherosclerosis, neuropathy, and cardiomyopathy. This review highlights recent studies that underscore the diagnostic and therapeutic potential of targeting epigenetic modifications in T2DM. We also provide an overview of the impact of lifestyle factors such as exercise and diet on the epigenetic landscape of T2DM, underscoring their relevance in disease management. Our synthesis of the current literature aims to illuminate the complex epigenetic underpinnings of T2DM, offering insights into novel preventative and therapeutic strategies that could revolutionize its management.

Association of HbA1c Variability with Vibrating Perception Threshold in Middle-Aged and Elderly Patients with Type 2 Diabetes Mellitus: A Retrospective Cohort Study

Purpose

To investigate the relationship between HbA1c variability and vibrating perception threshold (VPT) in middle-aged and elderly patients with type 2 diabetes mellitus (T2DM).

Patients and Methods

A total of 367 middle-aged and elderly patients with T2DM were enrolled. All patients were categorized into the control and vibration sensation deficiency group (VSD) based on VPT. Clinical data were collected. The coefficient of variation of glycated hemoglobin A1c (HbA1c-CV) and the mean glycated hemoglobin A1c(HbA1c-Mean) are considered as indexes of HbA1c variability. Multivariate logistic regression analysis, the generalized linear model and ROC curve correlation analysis were used to analyze the correlation of various factors and VPT.

Results

The multivariate logistic regression analysis revealed that age, systolic blood pressure (SBP), and HbA1c-CV were identified as risk factors for vibration sensation deficiency in middle-aged and elderly patients with T2DM, while estimated glomerular filtration rate (eGFR), triiodothyronine (T3), and alanine aminotransferase (ALT) were considered as protective factors. In the unadjusted generalized linear model, a significant association was observed between HbA1c-CV and VPT values. After adjusting for age, diabetic duration, SBP, homeostatic model assessment for beta-cell function (HOMA-β), ALT, eGFR, T3, 24-hour urinary protein excretion levels, and HbA1c-Mean, HbA1c-CV remained significantly correlated with VPT values on both sides. (left side, B=2.560, 95% CI 1.298~3.823; P<0.001; right side, B=2.608, 95% CI 1.498~3.718, P<0.001). The area under the curve (AUC) for HbA1c-CV and VSD prevalence was 0.723, with a sensitivity of 79.85%, specificity of 56.22%.

Conclusion

The risk of developing VSD increases proportionally with higher HbA1c-CV levels in middle-aged and elderly patients with T2DM. Reaching and maintaining blood glucose stability is essential to the mitigation of diabetes peripheral neuropathy occurrence.

Painful Diabetic Peripheral Neuropathy: Practical Guidance and Challenges for Clinical Management

Painful diabetic peripheral neuropathy (PDPN) is present in nearly a quarter of people with diabetes. It is estimated to affect over 100 million people worldwide. PDPN is associated with impaired daily functioning, depression, sleep disturbance, financial instability, and a decreased quality of life. Despite its high prevalence and significant health burden, it remains an underdiagnosed and undertreated condition. PDPN is a complex pain phenomenon with the experience of pain associated with and exacerbated by poor sleep and low mood. A holistic approach to patient-centred care alongside the pharmacological therapy is required to maximise benefit. A key treatment challenge is managing patient expectation, as a good outcome from treatment is defined as a reduction in pain of 30-50%, with a complete pain-free outcome being rare. The future for the treatment of PDPN holds promise, despite a 20-year void in the licensing of new analgesic agents for neuropathic pain. There are over 50 new molecular entities reaching clinical development and several demonstrating benefit in early-stage clinical trials. We review the current approaches to its diagnosis, the tools, and questionnaires available to clinicians, international guidance on PDPN management, and existing pharmacological and non-pharmacological treatment options. We synthesise evidence and the guidance from the American Association of Clinical Endocrinology, American Academy of Neurology, American Diabetes Association, Diabetes Canada, German Diabetes Association, and the International Diabetes Federation into a practical guide to the treatment of PDPN and highlight the need for future research into mechanistic-based treatments in order to prioritise the development of personalised medicine.

Nrf2 signaling in diabetic nephropathy, cardiomyopathy and neuropathy: Therapeutic targeting, challenges and future prospective

Western lifestyle contributes to an overt increase in the prevalence of metabolic anomalies including diabetes mellitus (DM) and obesity. Prevalence of DM is rapidly growing worldwide, affecting many individuals in both developing and developed countries. DM is correlated with the onset and development of complications with diabetic nephropathy (DN), diabetic cardiomyopathy (DC) and diabetic neuropathy being the most devastating pathological events. On the other hand, Nrf2 is a regulator for redox balance in cells and accounts for activation of antioxidant enzymes. Dysregulation of Nrf2 signaling has been shown in various human diseases such as DM. This review focuses on the role Nrf2 signaling in major diabetic complications and targeting Nrf2 for treatment of this disease. These three complications share similarities including the presence of oxidative stress, inflammation and fibrosis. Onset and development of fibrosis impairs organ function, while oxidative stress and inflammation can evoke damage to cells. Activation of Nrf2 signaling significantly dampens inflammation and oxidative damage, and is beneficial in retarding interstitial fibrosis in diabetic complications. SIRT1 and AMPK are among the predominant pathways to upregulate Nrf2 expression in the amelioration of DN, DC and diabetic neuropathy. Moreover, certain therapeutic agents such as resveratrol and curcumin, among others, have been employed in promoting Nrf2 expression to upregulate HO-1 and other antioxidant enzymes in the combat of oxidative stress in the face of DM.

Hypertension the 'Missed Modifiable Risk Factor' for Diabetic Neuropathy: a Systematic Review

Diabetes and hypertension stand as the major non-infectious diseases affecting 34.2 million and 1.28 billion people respectively. The literature on the impact of diabetes on hypertension and vice versa is evolving. The major objectives of this review were to compile the evolving literature establishing the role of hypertension in diabetic neuropathy, derive the exact mechanisms for its pathogenesis, and describe evidence-based precise individualized management of diabetic neuropathy in patients having diabetes complicated by hypertension. A systematic review was conducted by searching databases of PubMed, Embase, and Scopus covering the literature from inception to 2022. We included all observational and experimental studies, including both human and animal studies looking into the correlation between diabetic neuropathy and hypertension. Hypertension poses to be the leading modifiable risk factor for the development of diabetic neuropathy, especially distal symmetrical polyneuropathy, producing abnormal nerve conduction parameters and increased vibration perception threshold in patients with diabetes mellitus. Thus, we advocate that good glycemic control in patients with diabetes needs to be supported with strict blood pressure control for preventing and delaying the onset of diabetic neuropathy.

Effect of Surgical Release of Entrapped Peripheral Nerves in Sensorimotor Diabetic Neuropathy on Pain and Sensory Dysfunction-Study Protocol of a Prospective, Controlled Clinical Trial

BACKGROUND

Nerve entrapment has been hypothesized to contribute to the multicausal etiology of axonopathy in sensorimotor diabetic neuropathy. Targeted surgical decompression reduces external strain on the affected nerve and, therefore, may alleviate symptoms, including pain and sensory dysfunction. However, its therapeutic value in this cohort remains unclear.

AIM

Quantifying the treatment effect of targeted lower extremity nerve decompression in patients with preexisting painful sensorimotor diabetic neuropathy and nerve entrapment on pain intensity, sensory function, motor function, and neural signal conduction.

STUDY DESIGN

This prospective, controlled trial studies 40 patients suffering from bilateral therapy-refractory, painful (n = 20, visual analogue scale, VAS ≥ 5) or painless (n = 20, VAS = 0) sensorimotor diabetic neuropathy with clinical and/or radiologic signs of focal lower extremity nerve compression who underwent unilateral surgical nerve decompression of the common peroneal and the tibial nerve. Tissue biopsies will be analyzed to explore perineural tissue remodeling in correlation with intraoperatively measured nerve compression pressure. Effect size on symptoms including pain intensity, light touch threshold, static and moving two-point discrimination, target muscle force, and nerve conduction velocity will be quantified 3, 6, and 12 months postoperatively, and compared (1) to the preoperative values and (2) to the contralateral lower extremity that continues non-operative management.

CLINICAL SIGNIFICANCE

Targeted surgical release may alleviate mechanical strain on entrapped lower extremity nerves and thereby potentially improve pain and sensory dysfunction in a subset of patients suffering from diabetic neuropathy. This trial aims to shed light on these patients that potentially benefit from screening for lower extremity nerve entrapment, as typical symptoms of entrapment might be erroneously attributed to neuropathy only, thereby preventing adequate treatment.

Diabetic Neuropathy Assessed with Multifrequency Vibrometry Develops Earlier than Nephropathy but Later than Retinopathy

BACKGROUND

Diabetes is associated with systemic complications. Prevalence of diabetic nephropathy, and retinopathy, in type 1 diabetes mellitus (T1DM) is declining, but it is not known if this is true also for diabetic neuropathy.

AIM

To investigate the relationship between large fibre diabetic neuropathy and other diabetic complications.

MATERIALS AND METHODS

Neuropathy, defined here as large fibre neuropathy, was assessed by measuring vibration perception thresholds at four different frequencies on the sole of the foot, using a standard VibroSense Meter and/or neuropathic symptoms, in 599 individuals with T1DM. Retinopathy status was graded using the International Clinical Disease Severity Scale. Grade of albuminuria and previous history of any macrovascular complications were registered.

RESULTS

Diabetic individuals without retinopathy had similar vibration thresholds as age- and gender-matched control participants without diabetes, whereas those without microalbuminuria had higher thresholds than controls. Two individuals out of 599 (0.3%) had microalbuminuria, but not retinopathy or neuropathy, and 12/134 (9%) without retinopathy had signs of neuropathy. Totally 119/536 (22%) of the patients without microalbuminuria had neuropathy. Vibration thresholds increased with the rising severity of retinopathy and grade of albuminuria. In a multinomial logistic regression analysis, neuropathy was associated with retinopathy (OR 2.96 [1.35-6.49], p=0.007), nephropathy (OR 6.25 [3.21-12.15]; p=6.7×10-8) and macrovascular disease (OR 2.72 [1.50-4.93], p=0.001).

CONCLUSIONS

Despite recent changes in the incidence of diabetic complications, the onset of large fibre neuropathy follows that of retinopathy but precedes the onset of nephropathy in T1DM.

Endothelial-to-mesenchymal transition: An underappreciated mediator of diabetic complications

Diabetes and its complications represent a great burden on the global healthcare system. Diabetic complications are fundamentally diseases of the vasculature, with endothelial cells being the centerpiece of early hyperglycemia-induced changes. Endothelial-to-mesenchymal transition is a tightly regulated process that results in endothelial cells losing endothelial characteristics and developing mesenchymal traits. Although endothelial-to-mesenchymal transition has been found to occur within most of the major complications of diabetes, it has not been a major focus of study or a common target in the treatment or prevention of diabetic complications. In this review we summarize the importance of endothelial-to-mesenchymal transition in each major diabetic complication, examine specific mechanisms at play, and highlight potential mechanisms to prevent endothelial-to-mesenchymal transition in each of the major chronic complications of diabetes.

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

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

The efficacy and safety of traditional Chinese medicine physiotherapy combined with acupoint injection on diabetic peripheral neuropathy: A protocol for systematic review and meta-analysis

BACKGROUND

The efficacy and safety of traditional Chinese medicine physiotherapy combined with acupoint injection in treating diabetic peripheral neuropathy remains unknown. As a result, we will conduct a systematic review and meta-analysis to assess the evidence.

METHODS

We will look for pertinent randomized controlled trials in the following databases: China National Knowledge Infrastructure, WanFangData, Chinese biological medical database, Medline, Cochrane Library, PubMed, and Embase up to January 2022. Following the standards of Cochrane Review 6.2, 2 researchers independently evaluated the quality of the evidence in the relevant papers. Data analysis will be conducted by using Review Manager 5.4, including statistical analysis, subgroup analysis, making forest plot and funnel chart.

RESULTS

The results will be submitted to a peer-reviewed journal.

CONCLUSION

The research will verify the safety and efficacy of traditional Chinese medicine physiotherapy in combination with acupoint injection for diabetic peripheral neuropathy.

Prevention and Management Strategies for Diabetic Neuropathy

Diabetic neuropathy (DN) is a common complication of diabetes that is becoming an increasing concern as the prevalence of diabetes rapidly rises. There are several types of DN, but the most prevalent and studied type is distal symmetrical polyneuropathy, which is the focus of this review and is simply referred to as DN. It can lead to a wide range of sensorimotor and psychosocial symptoms and is a major risk factor for diabetic foot ulceration and Charcot neuropathic osteoarthropathy, which are associated with high rates of lower limb amputation and mortality. The prevention and management of DN are thus critical, and clinical guidelines recommend several strategies for these based on the best available evidence. This article aims to provide a narrative review of DN prevention and management strategies by discussing these guidelines and the evidence that supports them. First, the epidemiology and diverse clinical manifestations of DN are summarized. Then, prevention strategies such as glycemic control, lifestyle modifications and footcare are discussed, as well as the importance of early diagnosis. Finally, neuropathic pain management strategies and promising novel therapies under investigation such as neuromodulation devices and nutraceuticals are reviewed.

Foretinib mitigates cutaneous nerve fiber loss in experimental diabetic neuropathy

Diabetes is by far, the most common cause of neuropathy, inducing neurodegeneration of terminal sensory nerve fibers associated with loss of sensation, paresthesia, and persistent pain. Foretinib prevents die-back degeneration in cultured sensory and sympathetic neurons by rescuing mitochondrial activity and has been proven safe in prospective clinical trials. Here we aimed at investigating a potential neuroprotective effect of Foretinib in experimental diabetic neuropathy. A mouse model of streptozotocin induced diabetes was used that expresses yellow fluorescent protein (YFP) in peripheral nerve fibers under the thy-1 promoter. Streptozotocin-injected mice developed a stable diabetic state (blood glucose > 270 mg/dl), with a significant reduction of intraepidermal nerve fiber density by 25% at 5 weeks compared to the non-diabetic controls. When diabetic mice were treated with Foretinib, a significantly greater volume of the cutaneous nerve fibers (67.3%) in the plantar skin was preserved compared to vehicle treated (37.8%) and non-treated (44.9%) diabetic mice while proximal nerve fiber morphology was not affected. Our results indicate a neuroprotective effect of Foretinib on cutaneous nerve fibers in experimental diabetic neuropathy. As Foretinib treated mice showed greater weight loss compared to vehicle treated controls, future studies may define more sustainable treatment regimen and thereby may allow patients to take advantage of this neuroprotective drug in chronic neurodegenerative diseases like diabetic neuropathy.

Novel Nanotechnological Approaches for Targeting Dorsal Root Ganglion (DRG) in Mitigating Diabetic Neuropathic Pain (DNP)

Diabetic neuropathy is the most entrenched complication of diabetes. Usually, it affects the distal foot and toes, which then gradually approaches the lower part of the legs. Diabetic foot ulcer (DFU) could be one of the worst complications of diabetes mellitus. Long-term diabetes leads to hyperglycemia, which is the utmost contributor to neuropathic pain. Hyperglycemia causing an upregulation of voltage-gated sodium channels in the dorsal root ganglion (DRG) was often observed in models of neuropathic pain. DRG opening frequency increases intracellular sodium ion levels, which further causes increased calcium channel opening and stimulates other pathways leading to diabetic peripheral neuropathy (DPN). Currently, pain due to diabetic neuropathy is managed via antidepressants, opioids, gamma-aminobutyric acid (GABA) analogs, and topical agents such as capsaicin. Despite the availability of various treatment strategies, the percentage of patients achieving adequate pain relief remains low. Many factors contribute to this condition, such as lack of specificity and adverse effects such as light-headedness, languidness, and multiple daily doses. Therefore, nanotechnology outperforms in every aspect, providing several benefits compared to traditional therapy such as site-specific and targeted drug delivery. Nanotechnology is the branch of science that deals with the development of nanoscale materials and products, even smaller than 100 nm. Carriers can improve their efficacy with reduced side effects by incorporating drugs into the novel delivery systems. Thus, the utilization of nanotechnological approaches such as nanoparticles, polymeric nanoparticles, inorganic nanoparticles, lipid nanoparticles, gene therapy (siRNA and miRNA), and extracellular vesicles can extensively contribute to relieving neuropathic pain.

Itch in Adult Population with Type 2 Diabetes Mellitus: Clinical Profile, Pathogenesis and Disease-Related Burden in a Cross-Sectional Study

BACKGROUND

Despite growing interest in itch, data regarding itch in type 2 diabetes mellitus (DM2) are still limited, and mostly based on outdated studies. This study aimed to evaluate the clinical characteristics of itch in the adult population with DM2 and explore potential underlying causes.

METHODS

The study group consisted of 109 adult patients with DM2. Standardized questionnaires were completed in order to assess the itch intensity [Numerical Rating Scale (three days, 24hours) (NRS)] and the Four-item Itch Questionnaire (4IIQ) and to assess the psychological impact of itch [ItchyQoL, Six-Item Stigmatization Scale (6-ISS), Hospital Anxiety and Depression Scale (HADS)]. Skin dryness was evaluated clinically and by non-invasive assessment of epidermis moisturizing. Neuropathy was assessed using the clinical Katzenwadel neuropathy scale.

RESULTS

Itch occurred in 35.8% of adult patients with DM2, with NRSmax three days 6.31 ± 2.16 and 8.1 ± 3.5 points in 4IIQ. Itchy patients have had significantly higher FPG levels compared with the non-itchy population (p = 0.01). Patients with itch had a significantly higher possibility of neuropathy compared with non-itchy subjects (p < 0.01). Skin xerosis was significantly more advanced in patients with itch compared to those without (p < 0.01). The mean ItchyQol score was assessed as 41.2 ± 13.4 points, indicating mild life quality impairment and correlated positively with itch intensity. Itchy subjects had significantly higher scores in both anxiety and depression dimensions of HADS (in each p < 0.01).

CONCLUSIONS

We suggest that the primary cause of itch is prolonged poor diabetes control with altered glucose and insulin levels, subsequently causing skin dryness and neuropathy in long-lasting DM2.

Diabetic neuropathy: an insight on the transition from synthetic drugs to herbal therapies

The global pandemic of prediabetes and diabetes has led to a severe corresponding complication of these disorders. Neuropathy is one of the most prevalent complication of diabetes is, affecting blood supply of the peripheral nervous system that may eventually results into loss of sensations, injuries, diabetic foot and death. The utmost identified risk of diabetic neuropathy is uncontrolled high blood glucose levels. However, aging, body mass index (BMI), oxidative stress, inflammation, increased HbA1c levels and blood pressure are among the other key factors involved in the upsurge of this disease. The so far treatment to deal with diabetic neuropathy is controlling metabolic glucose levels. Apart from this, drugs like reactive oxygen species (ROS) inhibitors, aldose reductase inhibitors, PKC inhibitors, Serotonin-norepinephrine reuptake inhibitors (SNRIs), anticonvulsants, N-methyl-D-aspartate receptor (NMDAR) antagonists, are the other prescribed medications. However, the related side-effects (hallucinations, drowsiness, memory deficits), cost, poor pharmacokinetics and drug resistance brought the trust of patients down and thus herbal renaissance is occurring all over the word as the people have shifted their intentions from synthetic drugs to herbal remedies. Medicinal plants have widely been utilized as herbal remedies against number of ailments in Indian medicinal history. Their bioactive components are very much potent to handle different chronic disorders and complications with lesser-known side effects. Therefore, the current article mainly concludes the etiology and pathophysiology of diabetic neuropathy. Furthermore, it also highlights the important roles of medicinal plants and their naturally occurring bioactive compounds in addressing this disease.

Risk Factors for Diabetic Peripheral Neuropathy in Adolescents and Young Adults With Type 2 Diabetes: Results From the TODAY Study

OBJECTIVE

Data related to diabetic neuropathy in youth with type 2 diabetes are limited. We examined the relationship of glycemic control, sex, race/ethnicity, BMI, and other type 2 diabetes-associated factors with the development of diabetic peripheral neuropathy (DPN) in youth with type 2 diabetes enrolled in the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study.

RESEARCH DESIGN AND METHODS

The Michigan Neuropathy Screening Instrument (MNSI) and a 10-g monofilament exam were performed annually. DPN was defined as a score (>2) on the MNSI-exam or combined MNSI-exam and MNSI-survey scores (exam >2 and/or survey ≥4), or monofilament exam (<8 of 10 correct responses) at two or more consecutive visits. Multivariable time-to-event models assessed the association of risk factors evaluated longitudinally with DPN events.

RESULTS

A total of 674 participants (35% male), with a mean age of 14 years and diabetes duration <2 years at study entry, were evaluated annually over an average of 10.2 years. Male subjects had a significantly higher cumulative incidence of DPN than female subjects (38.5% vs. 27.2% via MNSI-exam, P = 0.002; 14.0% vs. 5.1% via monofilament exam, P = 0.01). Rates did not differ by race/ethnicity. Higher HbA1c and BMI were associated with higher DPN, by both MNSI and the monofilament test. In multivariable models, male sex, older age, and higher BMI were associated with MNSI-exam DPN risk.

CONCLUSIONS

DPN was evident early in the course of youth-onset type 2 diabetes and increased over time. It was higher in male subjects and related to glycemic control. These findings raise concern for long-term development of neuropathy-related morbidity in youth with type 2 diabetes and the need to achieve improved glycemic control.

Management of diabetic neuropathy

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

Association of Nonalcoholic Fatty Liver Disease (NAFLD) with Peripheral Diabetic Polyneuropathy: A Systematic Review and Meta-Analysis

Aims. The relationship between nonalcoholic fatty liver disease (NAFLD) and diabetic polyneuropathy (DPN) has been demonstrated in many studies, although results were conflicting. This meta-analysis aims to summarize available data and to estimate the DPN risk among NAFLD patients. Materials and methods. We performed a comprehensive literature review until 4 June 2021. Clinical trials analyzing the association between NAFLD and DPN were included. Results. Thirteen studies (9614 participants) were included. DPN prevalence was significantly higher in patients with NALFD, compared to patients without NAFLD (OR (95%CI) 2.48 (1.42–4.34), p = 0.001; I2 96%). This finding was confirmed in type 2 diabetes (OR (95%CI) 2.51 (1.33–4.74), p = 0.005; I2 97%), but not in type 1 diabetes (OR (95%CI) 2.44 (0.85–6.99), p = 0.100; I2 77%). Also, body mass index and diabetes duration were higher in NAFLD subjects compared to those without NAFLD (p < 0.001), considering both type 2 and type 1 diabetes. Conclusion. Despite a high heterogeneity among studies, a significantly increased DPN prevalence among type 2 diabetes subjects with NAFLD was observed. This result was not found in type 1 diabetes, probably due to the longer duration of disease. Physicians should pay more attention to the early detection of DPN, especially in patients with NAFLD.

Elevated blood and cerebrospinal fluid glucose levels affect the severity and short-term prognosis of Guillain-Barré syndrome

OBJECTIVE

This study aimed to explore the correlation of elevated glucose levels in the blood and cerebrospinal fluid with the progression and short-term prognosis of Guillain-Barré syndrome (GBS).

METHODS

The medical records of 982 patients who were diagnosed with GBS in 31 representative tertiary hospitals, located in 14 provinces in southern China, were collected and retrospectively reviewed. Patients were grouped according to the levels of fasting plasma glucose (FPG) and cerebrospinal fluid (CSF) glucose, as well as the concentration of blood hemoglobinAlc (HbA1c). The Hughes grade scale was used to quantify functional outcomes.

RESULTS

Compared to patients with normal FPG and CSF glucose levels, those in the high FPG and high CSF glucose groups were characterized by a higher proportion of severe patients (HFGS ≥ 3) at admission (58.8 vs. 73.1, P = 0.000; 57.6 vs. 71.2, P = 0.000), at nadir (67.4 vs. 83.0, P = 0.000; 66.2 vs. 80.4, P = 0.000), and at discharge (29.8 vs. 46.3, P = 0.000; 26.4 vs. 45.0, P = 0.000). Patients in the high HbA1c group also had more severe disability at admission (74.6 vs. 56.1, P = 0.005) and at nadir (80.3 vs. 64.3, P = 0.012) compared to the normal HbA1c group. Moreover, elevated levels of FPG and CSF glucose were significantly correlated with more severe disability at admission, at nadir, and at discharge.

CONCLUSIONS

The present study showed that elevated glucose levels in the blood and cerebrospinal fluid were associated with the severity and short-term prognosis of GBS.

TRIAL REGISTRATION

chicTR-RRc-17,014,152.

ABBREVIATIONS

GBS, Guillain-Barré syndrome; FPG, fasting plasma glucose; CSF, cerebrospinal fluid; HFGS, Hughes Functional Grading Scale; HbA1c, hemoglobin A1c. DM, diabetes mellitus; NCS, nerve conduction study; AIDP, acute inflammatory demyelinating polyneuropathy; AMAN, acute motor axonal neuropathy; AMSAN, acute motor sensory axonal neuropathy; MV, mechanical ventilation.

Inflammatory biomarkers as a part of diagnosis in diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN), a chronic neurological complication of diabetes mellitus, remains scantily addressed area of research. Many lacunae in the temporal sequence between cause and effect of DPN still remain unfilled and therefore treatment of DPN remains unsatisfactory. This is largely due to the conventional glucocentric focus to resolve the problem. This focus over hyperglycemia should be shifted to consider, chronic low grade inflammation as the major determinant in DPN. Rapidly emerging evidences from recent studies suggest that chronic low grade inflammation leads to the activation of innate immune system response, loss of insulin signaling and insulin resistance, endoplasmic reticulum stress, mitochondrial stress, leading to production of kinases like protein kinase C, mitogen activated protein kinase and jun-N-terminal kinase, pro-inflammatory cytokines and inter leukins-1b, 2, 6 and 8, tumour necrosis factor-alpha and other chemokines, leading to DPN. These biomarkers can be early predictors of DPN and therefore should be the focus of work testing their clinical utility to identify high-risk individuals as well as perhaps to target interventions. In this paper, we would like to review all the aspects of DPN, laying greater emphasis on inflammatory biomarkers as a tool for early diagnosis of DPN and the possible research approaches to address it satisfactorily.

Small Fiber Functionality in Patients with Diabetic Neuropathic Pain

OBJECTIVES

Diabetic neuropathic pain is associated with small fiber neuropathy. We aimed to assess the functionality of small fibers in patients with diabetes by using a practical method.

DESIGN

Patients with impaired glucose tolerance (IGT), diabetic neuropathic pain (DNP), type II diabetes mellitus without neuropathic pain, and healthy control were included. Axon-reflex flare responses were induced by the intradermal application of capsaicin and histamine at the distal leg. The associated flare characteristics (flare areas and flare intensities) were recorded by using Laser Speckle Contrast Analysis (LASCA). The pain and itch responses were rated while performing LASCA. To verify the structural properties of the small fibers, proximal and distal skin biopsies were performed.

RESULTS

DN4, MNSI, NRS, evoked-burning pain scores, and HbA1c levels were the highest in the DNP group. Compatible with length-dependent neuropathy, the distal skin PGP9.5-positive intraepidermal nerve fiber densities (IENFDs) were the lowest, whereas TRPV1-positive IENFDs were the highest in patients with DNP. The distal leg LASCA data showed hypo-functionality in both patients with IGT and DNP and association with disease severity.

CONCLUSION

There is an unmet need to practically assess the functionality of small fibers in patients with pain. In this study, a practical and objective method that does not need special expertise for the measurement of the functional properties of small fibers by using axon-flare responses is presented. The LASCA method could potentially facilitate a practical, quick (within 5 minutes), and very early diagnosis of small fiber hypo-functionality in both patients with IGT and DNP.

Serum Levels of Inflammatory Proteins Are Associated With Peripheral Neuropathy in a Cross-Sectional Type-1 Diabetes Cohort

Chronic low-grade inflammation is involved in the pathogenesis of type-1 diabetes (T1D) and its complications. In this cross-section study design, we investigated association between serum levels of soluble cytokine receptors with presence of peripheral neuropathy in 694 type-1 diabetes patients. Sex, age, blood pressure, smoking, alcohol intake, HbA1c and lipid profile, presence of DPN (peripheral and autonomic), retinopathy and nephropathy was obtained from patient’s chart. Measurement of soluble cytokine receptors, markers of systemic and vascular inflammation was done using multiplex immunoassays. Serum levels were elevated in in DPN patients, independent of gender, age and duration of diabetes. Crude odds ratios were significantly associated with presence of DPN for 15/22 proteins. The Odds ratio (OR) remained unchanged for sTNFRI (1.72, p=0.00001), sTNFRII (1.45, p=0.0027), sIL2Rα (1.40, p=0.0023), IGFBP6 (1.51, p=0.0032) and CRP (1.47, p=0.0046) after adjusting for confounding variables, HbA1C, hypertension and dyslipidemia. Further we showed risk of DPN is associated with increase in serum levels of sTNFRI (OR=11.2, p<10), sIL2Rα (8.69, p<10^-15), sNTFRII (4.8, p<10^-8) and MMP2 (4.5, p<10^-5). We combined the serum concentration using ridge regression, into a composite score, which can stratify the DPN patients into low, medium and high-risk groups. Our results here show activation of inflammatory pathway in DPN patients, and could be a potential clinical tool to identify T1D patients for therapeutic intervention of anti-inflammatory therapies.

Diabetic neuropathy in children and youth: New and emerging risk factors

Pediatric neuropathy attributed to metabolic dysfunction is a well-known complication in children and youth with type 1 diabetes. Moreover, the rise of obesity and in particular of type 2 diabetes may cause an uptick in pediatric neuropathy incidence. However, despite the anticipated increase in neuropathy incidence, pathogenic insights and strategies to prevent or manage neuropathy in the setting of diabetes and obesity in children and youth remain unknown. Data from adult studies and available youth cohort studies are providing an initial understanding of potential diagnostic, management, and preventative measures in early life. This review discusses the current state of knowledge emanating from these efforts, with particular emphasis on the prevalence, clinical presentation, diagnostic approaches and considerations, and risk factors of neuropathy in type 1 and type 2 diabetes in children and youth. Also highlighted are current management strategies and recommendations for neuropathy in children and youth with diabetes. This knowledge, along with continued and sustained emphasis on identifying and eliminating modifiable risk factors, completing randomized controlled trials to assess effectiveness of strategies like weight loss and exercise, and enhancing awareness to support early detection and prevention, are pertinent to addressing the rising incidence of neuropathy associated with diabetes and obesity in children and youth.

Risk of cardiac autonomic neuropathy in latent autoimmune diabetes in adults is similar to type 1 diabetes and lower compared to type 2 diabetes: A cross-sectional study

AIMS

Microvascular complications' risk differs between people with latent autoimmune diabetes in adults (LADA) and people with type 2 diabetes. We aimed to investigate whether the prevalence of cardiac autonomic neuropathy, a life-threatening complication of diabetes, also varies depending on diabetes type.

METHODS

In this cross-sectional study, 43 adults with LADA, 80 with type 1 diabetes and 61 with type 2 diabetes were screened for cardiac autonomic neuropathy with recommended tests. Logistic regression models were used to test differences between diabetes types adjusting for confounders.

RESULTS

Cardiac autonomic neuropathy was diagnosed in 17 (40%) participants with LADA, 21 (26%) participants with type 1 diabetes and 39 (64%) participants with type 2 diabetes (p < 0.001). The odds ratio (OR) for cardiac autonomic neuropathy in type 1 diabetes and in type 2 diabetes compared to LADA were 0.54 (95% CI: 0.25-1.20, p-value: 0.13) and 2.71 (95% CI: 1.21-6.06, p-value 0.015) respectively. Smoking (_adj OR 3.09, 95% CI: 1.40-6.82, p-value: 0.005), HDL cholesterol (_adj OR 0.29, 95% CI: 0.09-0.93, p-value: 0.037) and hypertension (_adj OR 2.11, 95% CI: 1.05-4.24, p-value: 0.037) were independent modifiable risk factors for cardiac autonomic neuropathy. Differences among diabetes types did not change after correction for confounders.

CONCLUSIONS

This is the first study offering a comparative evaluation of cardiac autonomic neuropathy among LADA, type 1 and type 2 diabetes, showing a lower risk of cardiac autonomic neuropathy in LADA compared to type 2 diabetes and similar compared to type 1 diabetes. This disparity was not due to differences in age, metabolic control or cardiovascular risk factors.

Dietary capsaicin normalizes CGRP peptidergic DRG neurons in experimental diabetic peripheral neuropathy

Diabetic sensory neuropathy leads to impairment of peripheral sensory nerves and downregulation of calcitonin gene-related peptide (CGRP) in a functionally specific subset of peripheral sensory neurons mediating pain. Whether CGRP plays a neuroprotective role in peripheral sensory nerve is unclear. We evaluated alterations in noxious thermal sensation and downregulation of CGRP in the 8 weeks after induction of diabetes in rats. We supplemented capsaicin in the diet of the animals to upregulate CGRP and reversed the downregulation of the neuropeptide in the dorsal root ganglion (DRG) neurons dissociated from the diabetic animals, via gene transfection and exogenous CGRP, to test disease-preventing and disease-limiting effects of CGRP. Significant preservation of the nociceptive sensation, CGRP in spinal cord and DRG neurons, and number of CGRP-expressing neurons was found in the diabetic animals given capsaicin. Improvement in the survival of the neurons and the outgrowth of neurites was achieved in the neurons transfected by LV-CGRP or by exogenous CGRP, paralleling the correction of abnormalities of intracellular reactive oxygen species and mitochondrial transmembrane potentials. The results suggest that downregulation of CGRP impairs viability, regeneration and function of peripheral sensory neurons while capsaicin normalizes the CGRP peptidergic DRG neurons and function of the sensory nerves.

A systematic review and meta-analysis of the serum lipid profile in prediction of diabetic neuropathy

Whether the lipid profile in diabetic patients is associated with diabetic neuropathy (DN) development remains ambiguous, as does the predictive value of serum lipid levels in the risk of DN. Here, we performed the first meta-analysis designed to investigate the relationship between DN and the serum levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL). Candidate studies were comprehensively identified by searching PubMed, Embase, Cochrane Library and Web of Science databases up to May 2020. Observational methodological meta-analysis was conducted to assess the relationships of TG, TC, HDL, and LDL levels with DN. Changes in blood lipids were used to estimate the effect size. The results were pooled using a random-effects or fixed-effects model. Potential sources of heterogeneity were explored by subgroup analysis. Various outcomes were included, and statistical analyses were performed using STATA (Version 12.0). Mean differences (MDs) and odds ratios (ORs) with 95% confidence intervals (CIs) were estimated. The Newcastle–Ottawa Scale (NOS) was applied to assess the methodological quality. I2 statistics were calculated to evaluate statistical heterogeneity. Funnel plots were utilized to test for publication bias. A sensitivity analysis was performed by omitting each study one by one. Thirty-nine clinical trials containing 32,668 patients were included in the meta-analysis. The results demonstrated that DN patients showed higher TG and lower HDL levels (MD = 0.34, 95% CI: 0.20–0.48 for TG; MD = -0.05, 95% CI: -0.08–-0.02, I² = 81.3% for HDL) than controls. Subgroup analysis showed that patients with type 1 diabetes mellitus (T1DM) neuropathy had elevated TG levels in their serum (MD = 0.25, 95% CI: 0.16–0.35,I² = 64.4% for T1DM). However, only patients with T1DM neuropathy had reduced serum HDL levels, and there was no significant difference in serum HDL levels between patients with T2DM neuropathy and controls (MD = -0.07, 95% CI: -0.10–-0.03, I² = 12.4% for T1DM; MD = -0.02, 95% CI: -0.07–0.03, I² = 80.2% for T2DM). TC and LDL levels were not significantly different between DN patients and controls (MD = -0.03, 95% CI: -0.14–0.09, I² = 82.9% for TC; MD = -0.00, 95% CI: -0.08–0.08, I² = 78.9% for LDL). In addition, compared with mild or painless DN patients, those with moderate or severe pain DN pain had significantly reduced serum TC and LDL levels (MD = -0.31, 95% CI: -0.49–-0.13, I² = 0% for TC; MD = -0.19, 95% CI: -0.32–-0.08, I² = 0% for LDL). TG levels and HDL levels did not vary considerably between patients with mild or painless DN and those with moderate or severe DN pain patients (MD = 0.12, 95% CI: -0.28–0.51, I² = 83.2% for TG; MD = -0.07, 95% CI:-0.14–0.01, I² = 58.8% for HDL). Furthermore, people with higher TG and LDL levels had higher risk of DN (OR = 1.36, 95% CI: 1.20–1.54, I² = 86.1% for TG and OR = 1.10, 95% CI: 1.02–1.19, I² = 17.8% for LDL). Conversely, high serum HDL levels reduced the risk of DN (OR = 0.85, 95% CI: 0.75–0.96, I² = 72.6%), while TC levels made no significant difference with the risk of DN (OR = 1.02, 95% CI: 1.00–1.04, I² = 84.7%). This meta-analysis indicated that serum lipid profile changes are among the biological characteristics of DN. Lipid levels should be explored as routine laboratory markers for predicting the risk of DN, as they will help clinicians choose appropriate therapies, and thus optimize the use of available resources.

The time to develop treatments for diabetic neuropathy

BACKGROUND

Diabetic neuropathy is a multifaceted condition affecting up to 50% of individuals with long standing diabetes. The most common presentation is peripheral diabetic sensory neuropathy (DPN).

METHODS

We carried out a systematic review of papers dealing with diabetic neuropathy on Pubmed in addition to a targeted Google search.Search terms included small fiber neuropathy,diffuse peripheral neuropathy, quantitative sensory testing, nerve conduction testing, intra-epidermal nerve fiber density, corneal confocal reflectance microscopy, aldose reductase inhbitors, nerve growth factor, alpha-lipoic acid, ruboxistaurin, nerve growth factor antibody, and cibinetide.

RESULTS

Over the past half century, there have been a number of agents undergoing unsuccessful trials for treatment of DPN.There are several approved agents for relief of pain caused by diabetic neuropathy, but these do not affect the pathologic process.

EXPERT OPINION

The failure to find treatments for diabetic neuropathy can be ascribed to (1) the complexity of design of studies and (2) the slow progression of the condition, necessitating long duration trials to prove efficacy.We propose a modification of the regulatory process to permit early introduction of agents with demonstrated safety and suggestion of benefit as well as prolongation of marketing exclusivity while long term trials are in progress to prove efficacy.

Inflammatory Biomarkers Levels in T2DM Emirati Patients with Diabetic Neuropathy

INTRODUCTION

Previous studies have suggested the involvement of chronic low-grade inflammation in the pathogenesis of diabetic neuropathy (DNP). However, none of these studies have examined the levels of monocyte chemoattractant protein-1 (MCP-1) in type 2 diabetes mellitus (T2DM) patients with confirmed diagnosis of neuropathy. Therefore, the present study aims to investigate the levels of MCP-1 along with IL-6, IL-8 and TGF-β in patients with T2DM and confirmed neuropathy and identify correlations, if any, between MCP-1 and other parameters.

METHODS

A single center cross-sectional clinical study was conducted at University Hospital Sharjah (UHS) and University of Sharjah. One hundred and two patients with T2DM were recruited from diabetes clinics at UHS and were stratified into different groups based on diagnosis of DNP and other parameters. Several analyses were conducted to evaluate and compare the levels of MCP-1, IL-6, IL-8, and TGF-β across these groups of patients and identify correlations, if any, between MCP-1 and other variables.

RESULTS

A significant increase was found in the levels of MCP-1 in T2DM patients with DNP compared to the patients without DNP (p=0.002, p-adj=0.007). Further analysis has shown that levels of IL-8 (p=0.008) and TGF-β (p=0.06) were increased and decreased, respectively, in patients with DNP compared to patients without DNP. Moreover, strong correlations were found between MCP-1, IL-8 and TGF-β levels.

CONCLUSION

The key finding of the present study is the significant elevation in levels of MCP-1 in T2DM patients with DNP compared to the patients without DNP and IL-8 and TGF-β were strong predictors of MCP-1 increased levels.

Associations between general and abdominal obesity and incident diabetic neuropathy in participants with type 2 diabetes mellitus

BACKGROUND

Previous epidemiological evidence on the sex-specific association of obesity, particularly abdominal obesity, as reflected by larger waist circumference (WC), with incident diabetic neuropathy (DN) remains limited.

METHODS

We used data from a patient cohort with a median 10-year history of type 2 diabetes mellitus at the time of recruitment. A composite outcome of four types of predefined DN (Neuro 1-4) was used as the outcome of interest. Because of sex differences in abdominal obesity, analyses were conducted separately for men and women.

RESULTS

Among the 7442 participants (4551 men and 2891 women) recruited in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study, 3999 cases of incident DN were documented (2529 in men and 1470 in women). Larger WCs were associated with a higher risk of DN among both men and women. Compared with the lowest quintile, the hazard ratio (HR) for the highest quintile was 1.30 (95% CI 1.13-1.49) among men (P_trend <.001). For women, the HR for the highest vs lowest quintile was 1.25 (95% CI 1.04-1.51) (P_trend <.001). A linear relationship between WC and DN was observed in men, and in women, the risk of DN increased as the WC quintile increased before it appeared to plateau. The relationship between body mass index and incident DN was similar to the results observed for WC.

CONCLUSION

General and abdominal obesity were both associated with an increased risk of incident DN among individuals with type 2 diabetes mellitus, regardless of sex.

Long-Term HbA1c, Physical Fitness, Nerve Conduction Velocities, and Quality of Life in Children with Type 1 Diabetes Mellitus-A Pilot Study

OBJECTIVE

The aim of this study was to examine a possible association of Hb_A1c, quality of life (QoL), fitness, and electrophysiological parameters in children with type 1 diabetes mellitus (T1DM).

METHODS

The study population (n = 34) consisted of patients with T1DM (n = 17) and an age-, sex-, and BMI-matched healthy control group (n = 17). Hb_A1c was obtained from patients with T1DM at time of diagnosis (T0), at 6 months (T6), at 12 months (T12), and at time of study inclusion (Tstudy). QoL was determined with a standardized questionnaire (KINDL-R). All children completed a 6-min walk test (6MWT) to evaluate their fitness level. Electrodiagnostic studies established upper and lower limb motor and sensory nerve conduction velocities (NCV).

RESULTS

Higher Hb_A1c (Tstudy) was associated with lower QoL showing in the subscales self-esteem, friends, and school. Higher Hb_A1c at (T6) and (T12) was associated with lower QoL in the subscale self-esteem. Based on various subscales, perceived problem areas differed significantly between children and their parents. No differences in fitness level and NCV were found between patients and controls except for a significantly slower median motor NCV in patients. Hb_A1c was not associated with NCVs at this early stage of disease.

CONCLUSIONS

Good metabolic control reflected by adequate Hb_A1c values seems to be important for a good QoL in children with T1DM. Early Hb_A1c might be associated with QoL during follow-up.

The metabolic drivers of neuropathy in India

AIMS

To determine the association between the metabolic syndrome (MetS) and neuropathy in Chennai, India.

METHODS

We recruited participants attending the M.V. Hospital for Diabetes. Neuropathy was defined using the Michigan Neuropathy Screening Instrument combined index and MetS was defined using the updated National Cholesterol Education Program criteria. Multivariable logistic regression models were used to assess the associations between individual metabolic components and neuropathy.

RESULTS

Of the 652 participants (42% female and mean (SD) age of 45.5 (9.7)) included in the study, the prevalence of neuropathy was 9.8%. Neuropathy prevalence increased with worsening glycemic status (p < 0.01), but not as the number of MetS components increased (p = 0.12). Among normoglycemic participants, an increasing neuropathy trend was observed as the number of MetS components increased (p = 0.04). Multivariable logistic regression found that diabetes (OR:3.41,1.28-9.11) was associated with neuropathy, but waist circumference was not (OR:1.002,0.88-1.14).

CONCLUSIONS

Similar to previous studies, diabetes was the most important metabolic risk factor for neuropathy in a population from Chennai, India. In contrast to other population-based studies, waist circumference was not associated with neuropathy. Whether the distribution of obesity affects nerves differently in Indian populations requires future studies with more precise anthropometric measures.

Moxibustion for the treatment of diabetic peripheral neuropathy: A systematic review and meta-analysis following PRISMA guidelines

BACKGROUND

At present, the effect of western-medicine (WM) therapy to treat diabetic peripheral neuropathy (DPN) is limited. Moxibustion is a representative external treatment in traditional Chinese medicine that has been beneficial to DPN. We aim to systematically assess the efficacy and safety of moxibustion in treating DPN, following PRISMA guidelines.

METHODS

Eight electronic databases were searched to acquire information on eligible trials published from inception to June 1, 2019. We included randomized controlled trials (RCTs) applying moxibustion therapy with a minimum of 14-days treatment duration for DPN patients compared with placebo, no intervention, or conventional WM interventions. The primary outcomes in our study include the sensory-nerve conduction velocity (SNCV) and motor-nerve conduction velocity (MNCV). We used the Cochrane Collaboration Risk of Bias tool to assess the methodological quality of eligible RCTs. Statistical analyses were conducted using Review Manager 5.3. Risk ratios (RR) and mean differences (MD) were calculated with a 95% confidence interval (CI). The χ test was applied to assess the heterogeneity.

RESULTS

In total, 11 RCTs were included that involved 927 DPN patients. Compared with the control group, there was an increase in median MNCV (MD = 6.26, 95% CI 2.64-9.89, Z = 3.39, P = .0007) and peroneal MNCV (MD = 6.45, 95% CI 5.30-7.61, P < .00001). There was also an increase in median SNCV (MD = 6.64, 95% CI 3.25-10.03, P = .0001) and peroneal SNCV (MD = 3. 57, 95% CI 2.06-5.09, Z = 4.63, P < .00001) in the treatment groups. The treatment groups receiving moxibustion therapy indicated a more significant improvement in total effectiveness rate (RR = 0.25, 95% CI 0.18-0.37, Z = 7.16, P < .00001). Toronto Clinical Scoring System indicated a significant decrease in the treatment groups (MD = -2.12, 95% CI -2.82 to 1.43, P < .00001). Only 1 study reported that treatment groups experienced no adverse reactions. The other 10 studies did not mention adverse events.

CONCLUSIONS

Moxibustion therapy may be an effective and safe option for DPN patients but needs to be verified in further rigorous studies.

A study of nerve conduction velocity in diabetic patients and its relationship with tendon reflexes (T-Reflex)

Background and Objective:

Neuropathy is one of the most common complications of diabetes mellitus. Neuropathy can cause sensory deficit, neurological disorder, organ ulcers, osteomyelitis, and amputation. Therefore, neurological examinations, determining the nerve conduction velocity and performing sensory and motor tests are important for timely diagnosis and treatment. The present study aimed to investigate the nerve conduction velocity in diabetic patients and its relationship with tendon reflexes.

Materials and Methods:

The present study was observational-cross sectional research carried out on 77 diabetic patients who admitted to the EMG / NCV Department of Shariati Hospital in the academic year 1996-1997. In all patients, the medical history of the patient (age, duration of diabetes, gender and age of onset of diabetes), neurological examination, nerve conduction velocity, heat test, vibration test, tendon reflexes, D.L and Amplitude were examined and recorded. Finally, the raw data obtained was entered into the IBM SPSS Statistics software and the important relationships between these variables were analyzed. Moreover, in present study, the statistical significance level (P-value) was considered less than 0.05.

Results:

The present study was conducted on a population consisting of 48 women and 29 men with diabetes. The age range of participants was 14-70 years old with an average age of 50.506 ± 7.50. The results of present study showed that the participants with clinical neuropathy (11.2 ± 7.2) had significantly longer duration of diabetes than the normal group and those participants with sub-clinical neuropathy (P-value = 0.12). Statistical analyses indicated that increase in age, increase in the duration of diabetes and the gender of male significantly made the nerve conduction velocity abnormal. The analysis of the response to neural reflexes indicated that the ratio of neurological disorders in the five nerves of the ankle and knee was generally higher in the abnormal group (the patients with nerve conduction disorder) compared to the normal (the patients with normal nerve conduction) and in some cases, such as the ulnar motor nerve of ankle (P-value = 0.010), and the ulnar motor nerve of knee motor (P-value = 0.002) and also in the peroneal motor nerve of knee (P-value = 0.003) and the sural sensory nerve of knee (P-value = 0.003), increase in neurological disorders was significant.

Conclusion:

Increase in age, increase in the duration of diabetes and the gender of male can significantly make the nerve conduction velocity abnormal. (www.actabiomedica.it)

State-of-the-art pharmacotherapy for diabetic neuropathy

INTRODUCTION

The global epidemic of diabetes has led to an epidemic of diabetes complications. Diabetic neuropathy is the most common microvascular complication, of which diabetic peripheral neuropathy (DPN) and autonomic neuropathy (AN) are the most prevalent, affecting ~50% of patients. DPN results in pain with a poor quality of life and a loss of sensation with an increased risk of foot ulceration. Autonomic neuropathy can cause significant morbidity in a minority and is associated with increased mortality. The cornerstone of treatment to prevent or limit the progression of DPN/AN is multifactorial risk factor modification including treatment of glycemia, lipids and blood pressure. Whilst, there are no FDA-approved disease-modifying therapies, there are a number of therapies to relieve symptoms in DPN and AN.

AREAS COVERED

The authors discuss current approved therapies for painful diabetic neuropathy and autonomic neuropathy. They also address the potential role of improving risk factors to limit the development and progression of diabetic neuropathy and new pathogenetic and pain-relieving treatments.

EXPERT OPINION

The FDA-approved Pregabalin and Duloxetine over 25 years ago and Tapentadol, 6 years ago for painful diabetic neuropathy. There are currently no FDA-approved disease-modifying treatments for diabetic neuropathy which has been attributed to inappropriate models of the disease with limited translational capacity and major limitations of trial designs and endpoints in clinical trials.

The Utility of Corneal Nerve Fractal Dimension Analysis in Peripheral Neuropathies of Different Etiology

Purpose

Quantification of corneal confocal microscopy (CCM) images has shown a significant reduction in corneal nerve fiber length (CNFL) in a range of peripheral neuropathies. We assessed whether corneal nerve fractal dimension (CNFrD) analysis, a novel metric to quantify the topological complexity of corneal subbasal nerves, can differentiate peripheral neuropathies of different etiology.

Methods

Ninety patients with peripheral neuropathy, including 29 with diabetic peripheral neuropathy (DPN), 34 with chronic inflammatory demyelinating polyneuropathy (CIDP), 13 with chemotherapy-induced peripheral neuropathy (CIPN), 14 with human immunodeficiency virus-associated sensory neuropathy (HIV-SN), and 20 healthy controls (HCs), underwent CCM for estimation of corneal nerve fiber density (CNFD), CNFL, corneal nerve branch density (CNBD), CNFrD, and CNFrD adjusted for CNFL (ACNFrD).

Results

In patients with DPN, CIDP, CIPN, or HIV-SN compared to HCs, CNFD (P = 0.004-0.0001) and CNFL (P = 0.05-0.0001) were significantly lower, with a further significant reduction among subgroups. CNFrD was significantly lower in patients with CIDP compared to HCs and patients with HIV-SN (P = 0.02-0.0009) and in patients with DPN compared to HCs and patients with HIV-SN, CIPN, or CIDP (P = 0.001-0.0001). ACNFrD was lower in patients with CIPN, CIDP, or DPN compared to HCs (P = 0.03-0.0001) and in patients with DPN compared to those with HIV-SN, CIPN, or CIDP (P = 0.01-0.005).

Conclusions

CNFrD can detect a distinct pattern of corneal nerve loss in patients with DPN or CIDP compared to those with CIPN or HIV-SN and controls.

Translational Relevance

Various peripheral neuropathies are characterized by a comparable degree of corneal nerve loss. Assessment of corneal nerve topology by CNFrD could be useful in differentiating neuropathies based on the pattern of loss.

Diabetic Distal Symmetrical Polyneuropathy: Correlation of Clinical, Laboratory, and Electrophysiologic Studies in Patients with Type 2 Diabetes Mellitus

This cross-sectional study is aimed at determining the prevalence of distal symmetrical polyneuropathy (DSPN) and diabetic peripheral neuropathic pain (DPNP) in participants with type 2 diabetes mellitus (T2DM); finding the risk factors for DSPN and DPNP via biochemical tests; and correlating DSPN and DPNP with the results of electrophysiologic studies, quantitative sensory tests, and neurologic examination. The 145 participants with T2DM enrolled were divided into the DSPN (abnormal nerve conduction studies (NCS) with signs of polyneuropathy), subclinical DSPN (abnormal NCS without signs of polyneuropathy), minimal DSPN (normal NCS with signs of polyneuropathy), and no DSPN groups. The biochemical risk factors of diabetic peripheral neuropathy were investigated. Neurologic examinations, laboratory tests, NCS, vibration threshold tests, and thermal threshold tests were conducted. The modified Michigan Neuropathy Screening Instrument (mMNSI) and Douleur Neuropathique 4 were used to evaluate the severity of DSPN and DPNP, respectively. In all, 30% of participants had DSPN and 11% had DPNP. DSPN correlated strongly with male gender and higher glycohaemoglobin levels; NCS abnormality correlated with higher glycohaemoglobin levels; DSPN severity correlated with NCS of each stimulating nerve. DPNP commonly occurred with clinical and electrophysiologic evidence of DSPN. Symptomatic diabetic polyneuropathy significantly correlated with longer disease duration, higher glycohaemoglobin levels, and abnormal vibration tests. The thermal threshold test combined with nerve conduction tests could detect most of the patients with DSPN, subclinical DSPN, and minimal DSPN. Poor diabetic control was independently associated with the development of DSPN. DPNP was associated with DSPN. The combination of thermal threshold tests with NCS can potentially provide the diagnosis of DSPN.

Central Obesity is Associated With Neuropathy in the Severely Obese

OBJECTIVE

To determine the prevalence of neuropathy stratified by glycemic status and the association between extensive anthropometric measurements and neuropathy.

PATIENTS AND METHODS

We performed a cross-sectional, observational study in obese individuals, before surgery, with body mass index (BMI) greater than 35 kg/m². Lean controls were recruited from a research website. Neuropathy was defined by the Toronto consensus definition of probable neuropathy. We compared nine anthropometric measurements between obese participants with and without neuropathy. We used multivariable logistic regression to explore associations between these measures, and other metabolic risk factors, and neuropathy.

RESULTS

We recruited 138 obese individuals and 46 lean controls. The mean age (SD) was 45.1 (11.3) years in the obese population (76.1% female, n=105) and 43.8 (12.1) years in the lean controls (82.2% female, n=37). The prevalence of neuropathy was 2.2% (n=1) in lean controls, 12.1% (n=4) in obese participants with normoglycemia, 7.1% (n=4) in obese participants with pre-diabetes, and 40.8% (n=20) in obese participants with diabetes (p≤.01). Waist circumference was the only anthropometric measure that was larger in those with neuropathy (139.3 cm vs 129.1 cm, p=.01). Hip-thigh (71.1 cm vs 76.6 cm, p<.01) and mid-thigh (62.2 cm vs 66.3 cm, p=.03) circumferences were smaller in those with neuropathy. The body mass index was comparable between patients who were obese with and without neuropathy (p=.86). Waist circumference (odds ratio [OR], 1.39; 95% CI, 1.10 to 1.75), systolic blood pressure (OR, 2.89; 95% CI, 1.49 to 5.61), and triglycerides (OR, 1.31; 95% CI, 1.00 to 1.70) were significantly associated with neuropathy.

CONCLUSION

Normoglycemic obese patients have a high prevalence of neuropathy indicating that obesity alone may be sufficient to cause neuropathy. Waist circumference, but not general obesity, is significantly associated with neuropathy.

Genetics of diabetes mellitus and diabetes complications

Diabetes is one of the fastest growing diseases worldwide, projected to affect 693 million adults by 2045. Devastating macrovascular complications (cardiovascular disease) and microvascular complications (such as diabetic kidney disease, diabetic retinopathy and neuropathy) lead to increased mortality, blindness, kidney failure and an overall decreased quality of life in individuals with diabetes. Clinical risk factors and glycaemic control alone cannot predict the development of vascular complications; numerous genetic studies have demonstrated a clear genetic component to both diabetes and its complications. Early research aimed at identifying genetic determinants of diabetes complications relied on familial linkage analysis suited to strong-effect loci, candidate gene studies prone to false positives, and underpowered genome-wide association studies limited by sample size. The explosion of new genomic datasets, both in terms of biobanks and aggregation of worldwide cohorts, has more than doubled the number of genetic discoveries for both diabetes and diabetes complications. We focus herein on genetic discoveries for diabetes and diabetes complications, empowered primarily through genome-wide association studies, and emphasize the gaps in research for taking genomic discovery to the next level.

Risk Factors for Diabetic Peripheral Neuropathy and Cardiovascular Autonomic Neuropathy in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study

The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study demonstrated that intensive glucose control reduced the risk of developing diabetic peripheral neuropathy (DPN) and cardiovascular autonomic neuropathy (CAN). We evaluated multiple risk factors and phenotypes associated with DPN and CAN in this large, well-characterized cohort of participants with type 1 diabetes, followed for >23 years. DPN was defined by symptoms, signs, and nerve conduction study abnormalities in ≥2 nerves; CAN was assessed using standardized cardiovascular reflex tests. Generalized estimating equation models assessed the association of DPN and CAN with individual risk factors measured repeatedly. During DCCT/EDIC, 33% of participants developed DPN and 44% CAN. Higher mean HbA_1c was the most significant risk factor for DPN, followed by older age, longer duration, greater height, macroalbuminuria, higher mean pulse rate, β-blocker use, and sustained albuminuria. The most significant risk factor for CAN was older age, followed by higher mean HbA_1c, sustained albuminuria, longer duration of type 1 diabetes, higher mean pulse rate, higher mean systolic blood pressure, β-blocker use, estimated glomerular filtration rate <60 mL/min/1.73 m², higher most recent pulse rate, and cigarette smoking. These findings identify risk factors and phenotypes of participants with diabetic neuropathy that can be used in the design of new interventional trials and for personalized approaches to neuropathy prevention.

The Contemporary Prevalence of Diabetic Neuropathy in Type 1 Diabetes: Findings From the T1D Exchange

OBJECTIVE

To evaluate the contemporary prevalence of diabetic peripheral neuropathy (DPN) in participants with type 1 diabetes in the T1D Exchange Clinic Registry throughout the U.S.

RESEARCH DESIGN AND METHODS

DPN was assessed with the Michigan Neuropathy Screening Instrument Questionnaire (MNSIQ) in adults with ≥5 years of type 1 diabetes duration. A score of ≥4 defined DPN. Associations of demographic, clinical, and laboratory factors with DPN were assessed.

RESULTS

Among 5,936 T1D Exchange participants (mean ± SD age 39 ± 18 years, median type 1 diabetes duration 18 years [interquartile range 11, 31], 55% female, 88% non-Hispanic white, mean glycated hemoglobin [HbA1c] 8.1 ± 1.6% [65.3 ± 17.5 mmol/mol]), DPN prevalence was 11%. Compared with those without DPN, DPN participants were older, had higher HbA1c, had longer duration of diabetes, were more likely to be female, and were less likely to have a college education and private insurance (all P < 0.001). DPN participants also were more likely to have cardiovascular disease (CVD) (P < 0.001), worse CVD risk factors of smoking (P = 0.008), hypertriglyceridemia (P = 0.002), higher BMI (P = 0.009), retinopathy (P = 0.004), reduced estimated glomerular filtration rate (P = 0.02), and Charcot neuroarthropathy (P = 0.002). There were no differences in insulin pump or continuous glucose monitor use, although DPN participants were more likely to have had severe hypoglycemia (P = 0.04) and/or diabetic ketoacidosis (P < 0.001) in the past 3 months.

CONCLUSIONS

The prevalence of DPN in this national cohort with type 1 diabetes is lower than in prior published reports but is reflective of current clinical care practices. These data also highlight that nonglycemic risk factors, such as CVD risk factors, severe hypoglycemia, diabetic ketoacidosis, and lower socioeconomic status, may also play a role in DPN development.

Diabetic Neuropathy Is a Substantial Burden in People With Type 1 Diabetes and Is Strongly Associated With Socioeconomic Disadvantage: A Population-Representative Study From Scotland

OBJECTIVE

To assess the contemporaneous prevalence of diabetic peripheral neuropathy (DPN) in people with type 1 diabetes (T1D) in Scotland and study its cross-sectional association with risk factors and other diabetic complications.

RESEARCH DESIGN AND METHODS

We analyzed data from a large representative sample of adults with T1D (N = 5,558). We assessed the presence of symptomatic neuropathy using the dichotomized (≥4) Michigan Neuropathy Screening Instrument Patient Questionnaire score. Logistic regression models were used to investigate associations between DPN and risk factors, as well as with other complications.

RESULTS

The burden of DPN is substantial with 13% prevalence overall. Adjusting for attained age, diabetes duration, and sex, the odds of DPN increased mainly with waist-to-hip ratio, lipids, poor glycemic control (odds ratio 1.51 [95% CI 1.21-1.89] for levels of 75 vs. 53 mmol/mol), ever versus never smoking (1.67 [1.37-2.03]), and worse renal function (1.96 [1.03-3.74] for estimated glomerular filtration rate levels <30 vs. ≥90 mL/min/1.73 m²). The odds significantly decreased with higher HDL cholesterol (0.77 [0.66-0.89] per mmol/L). Living in more deprived areas was associated with DPN (2.17 [1.78-2.65]) for more versus less deprived areas adjusted for other risk factors. Finally, individuals with prevalent DPN were much more likely than others to have other diabetes complications.

CONCLUSIONS

Diabetic neuropathy remains substantial, particularly affecting those in the most socioeconomically deprived groups. Those with clinically manifest neuropathy also have a higher burden of other complications and elevated levels of modifiable risk factors. These data suggest that there is considerable scope to reduce neuropathy rates and narrow the socioeconomic differential by better risk factor control.

Polyneuropathy in Severely Obese Women Without Diabetes: Prevalence and Associated Factors

BACKGROUND

Obesity and its complications are prevalent in women and increase with age. Polyneuropathy (PNP) is a complication of obesity and bariatric surgery (BS). In subjects with severe (grades II and III) obesity and without DM who are candidates for BS, the prevalence of PNP and associated conditions are not well characterized. The aim of this study was to evaluate the prevalence of PNP in severely obese (SO) women without DM or common nutritional deficiencies in order to determine factors associated with the presence of PNP.

METHODS

A cross-sectional study was performed on 450 SO women. They were evaluated with the Michigan Neuropathy Screening Instrument, a Sleep Apnea Questionnaire, and the short form of the International Physical Activity Questionnaire. Data on blood pressure, body mass index, waist circumference, serum glucose, glycated hemoglobin, LDL and HDL cholesterol, triglycerides, vitamin B12, and postmenopausal (PM) status were also collected. Patients with DM and other common causes of PNP were excluded. To evaluate which variables were independently associated with PNP (dependent variable), Poisson regression models were used.

RESULTS

The prevalence of PNP was 11.6%. In univariate analysis, PNP was associated with age, PM status, and diagnosis of systemic arterial hypertension (p < 0.001, p < 0.001, and p = 0.016, respectively), and there was a trend toward an association with sleep apnea risk (p = 0.101). In multivariate analysis, PM status (PR = 2.836, 95% CI 1.735-4.636, p = 0.001) and age (PR = 1.0511, 95% CI 1.031-1.071, p = 0.001) were independently associated with PNP diagnosis in two different models.

CONCLUSION

Even prior to BS, PNP is highly prevalent and is associated with PM status and age in SO women without diabetes.

Suppression of HDAC by sodium acetate rectifies cardiac metabolic disturbance in streptozotocin-nicotinamide-induced diabetic rats

Diabetes mellitus, particularly type 2 occurs at global epidemic proportions and leads to cardiovascular diseases. Molecular studies suggest the involvement of epigenetic alterations such as histone code modification in the progression of cardiometabolic disorders. However, short chain fatty acids (SCFAs) are recognized as epigenetic modulators by their histone deacetylase inhibitory property. It is therefore hypothesized that cardiac histone deacetylase activity increases in type II diabetes and SCFA, acetate, would inhibit histone deacetylase with accompanying restoration of glucose dysregulation, cardiac lipid deposition, and tissue damage in male Wistar rats. Twenty-four male rats (240–270 g) were allotted into four groups ( n = 6 per group) namely: vehicle-treated ( p.o.), sodium acetate-treated (200 mg/kg), diabetic, and diabetic+sodium acetate-treated groups. Diabetes was induced by intraperitoneal injection of streptozotocin 65 mg/kg after a dose of nicotinamide 110 mg/kg. The results showed that diabetic rats had, glucose dysregulation, elevated serum and cardiac triglyceride, malondialdehyde, alanine aminotransferase, histone deacetylase, serum aspartate transaminase, cardiac low density lipoprotein cholesterol (LDLc), glutathione/glutathione disulphide ratio (GSH/GSSG), reduced serum and cardiac high density lipoprotein cholesterol (HDLc), and serum GSH/GSSG. Histological analysis revealed disrupted cardiac fiber in diabetic rats. However, sodium acetate attenuated glucose dysregulation and improved serum and cardiac GSH/GSSG. Sodium acetate normalized cardiac triglyceride accumulation, malondialdehyde, serum aspartate transaminase levels and prevented cardiac tissue damage in diabetic rats. These effects were associated with suppressed histone deacetylase activity. Therefore, sodium acetate attenuated but failed to normalize glucoregulation. Nevertheless, it ameliorated oxidative stress- and lipid dysmetabolism-driven cardiovascular complications in diabetic rats by the suppression of histone deacetylase activity.

Impact statement

This study provides evidence that STZ-NA-induced diabetes mellitus is associated with cardiac triglyceride accumulation and tissue disruption with corresponding increase in cardiac HDAC activity. However, sodium acetate suppresses cardiac HDAC activity and normalizes cardiac triglyceride and tissue integrity in diabetic rats. Therefore, the study suggests that sodium acetate is beneficial for cardioprotection in diabetes mellitus.

Diffusion tensor imaging MR Neurography detects polyneuropathy in type 2 diabetes

AIM

To evaluate if diffusion-tensor-imaging MR-Neurography (DTI-MRN) can detect lesions of peripheral nerves due to polyneuropathy in patients with type 2 diabetes.

METHODS

Ten patients with type 2 diabetes with polyneuropathy (DPN), 10 patients with type 2 diabetes without polyneuropathy (nDPN) as well as 20 healthy controls (HC) were included. DTI-MRN covered proximal (sciatic nerve) and distal regions (tibial nerve) of the lower extremity. Fractional-anisotropy (FA) and diffusivity (mean (MD), axial (AD) and radial (RD)) were calculated and compared to neuropathy severity. Conventional T2-relaxation-time and proton-spin-density data were obtained from a multi-echo SE sequence. Furthermore, we evaluated sensitivity and specificity of DTI-MRN from receiver operating characteristics (ROC).

RESULTS

The proximal and distal FA was lowest in patients with DPN compared with nDPN and HC (p < 0.01). Likewise, proximal and distal RD was highest in patients with DPN (p < 0.01). MD and AD were also significantly different though less pronounced. ROC curve analyses of DTI separated nDPN and DPN with area-under-the-curve values ranging from 0.65 to 0.98. T2-relaxation-time and proton-spin-density could not differentiate between nDPN and DPN.

CONCLUSION

DTI-MRN accurately detects DPN by lower nerve FA and higher RD. These alterations are likely to reflect both proximal and distal nerve fiber pathology in patients with type 2 diabetes.

Biomarkers of response to alpha-lipoic acid ± palmitoiletanolamide treatment in patients with diabetes and symptoms of peripheral neuropathy

PURPOSE

To evaluate the effect of oral alpha-lipoic acid (ALA) ± palmitoyl-ethanolamide (PEA) on neuropathic symptoms in patients with diabetic peripheral neuropathy (DPN) and to identify factors related to the efficacy of the treatment.

METHODS

This is a retrospective observational pilot study evaluating 49 patients with diabetes and positive Neuropathy Symptoms Score (NSS). Clinical and biochemical variables, including NSS, were compared between untreated patients and patients treated with oral 600 mg/day ALA ± 600 mg/day PEA at baseline (first occurrence of NSS ≥ 3) and at least 2 months after baseline. Number of days between treatment initiation and symptoms' relief and related factors were also investigated.

RESULTS

Thirty subjects were treated with ALA ± PEA and 19 subjects did not receive any specific treatment for neuropathy symptoms. Follow-up visits occurred after 98 ± 46 days. NSS significantly decreased in patients treated with ALA ± PEA (5.4 ± 1.3 at baseline vs. 1.7 ± 2.4 at follow-up, p < 0.001), but not in untreated patients (p = 0.164). Subjects treated with ALA ± PEA reported a mean time from treatment initiation to symptoms' relief of 18.4 ± 9.0 days. The number of days of treatment needed for symptoms' relief was inversely related to HDL-cholesterol levels (r = -0.503, p = 0.010) and to eGFR (r = -0.428, p = 0.033), whereas there was no significant relationship between time to symptoms' relief and age, HbA1c, lipid profile and the severity of symptoms at baseline.

CONCLUSIONS

This study documents that oral administration of ALA ± PEA helps in controlling neuropathy symptoms in diabetes. Moreover, our data show that higher HDL-c levels and better renal function are associated to a faster therapeutic effect, suggesting them as biomarkers of response to therapy with ALA ± PEA.