Diabetic Peripheral Neuropathy Group Research Articles

Comprehensive assessment of ocular parameters for identifying diagnostic indicators of diabetic peripheral neuropathy.

To explore variations in systemic and ocular parameters among patients with diabetes, both with and without diabetic peripheral neuropathy (DPN) and to identify sensitive indicators for DPN diagnosis. Ninty-five patients with type 2 diabetes mellitus (T2DM) were involved in this cross-sectional study, including 49 without DPN and 46 with DPN. Ocular parameters were obtained using optical coherence tomography angiography (OCTA) and corneal confocal microscopy (CCM). Patients with DPN presented with significantly higher HbA1c (p < 0.05) and glycated albumin (GA, p < 0.01) levels, increased prevalence of diabetic retinopathy (DR, p < 0.05), and lower serum albumin (ALB, p < 0.01) and red blood cell (RBC, p < 0.05) levels. Ocular assessments revealed reduced corneal nerve fiber length (CNFL, p < 0.001) and enlarged foveal avascular zone (FAZ) area (p < 0.05) in DPN group. Logistic regression analysis indicated a significant association of presence of DR, RBC, GA, ALB, CNFL and DPN (p < 0.05, respectively). In the binary logistic regression for DPN risk, all three models including the presence of DR and CNFL exhibited the area under the curve (AUC) exceeding 0.8. The study establishes a strong correlation between ocular parameters and DPN, highlighting CCM's role in early diagnosis. Combining systemic and ocular indicators improves DPN risk assessment and early management.

Effects of individually optimized rocker midsoles and self-adjusting insoles on dynamic stability in persons with diabetes mellitus and neuropathy

BackgroundPersons with diabetic peripheral neuropathy (DPN) may face challenges such as balance issues due to reduced somatosensory feedback and an increased risk of developing diabetic foot ulcers (DFUs) due to increased plantar pressure. Pressure reducing footwear is thought to further impair balance. We introduced 3D-printed rocker midsoles and self-adjusting insoles that are able to reduce elevated plantar pressure values and aimed to prevent balance deterioration. However, their effect on the balance during walking (dynamic stability) is not analyzed yet. Research questionIs dynamic stability of persons with DPN impaired compared to healthy individuals and what is the effect of the 3D-printed rocker midsoles and self-adjusting insoles on the dynamic stability in this population? MethodsDynamic stability, specifically the margins of stability (MOS) in the anterior-posterior (AP) and medio-lateral (ML) direction, was measured in ten healthy and nineteen persons with DPN. Independent-samples t-test was applied to analyze the difference in the MOS between groups. One-way repeated measures analyses of variance (ANOVA) was conducted to test the difference between the therapeutic footwear combinations within the DPN group. ResultsThere is no significant difference between the healthy and DPN group in MOS-AP. MOS-ML is significantly larger in DPN compared to the healthy participants. Using the self-adjusting insole shows a significantly lower (negative) MOS-AP compared to when using a rocker shoe within the DPN group. SignificanceThis study provides valuable information on whether DPN and our therapeutic footwear have a negative effect on the dynamic stability. DPN does not have a negative effect on dynamic stability in the AP direction. For the ML direction, DPN seems to cause larger MOS-ML by likely using a compensation strategy (e.g., wider steps) while our experimental footwear does not further impair the MOS-ML.

Protective Role of MerTK in Diabetic Peripheral Neuropathy via Inhibition of the NF-κB Signaling Pathway.

Diabetic peripheral neuropathy (DPN) impacts patient quality of life. In such patients, increased expression of mer tyrosine kinase (MerTK) has been demonstrated; however, its mechanism of action remains unclear. In this study, type 2 diabetes mellitus (T2DM) and DPN models were established in Sprague Dawley rats via low-dose streptozotocin and a high-fat diet and the mode of action of MerTK was examined. MerTK-specific inhibitors were administered by gavage once daily for 2 weeks. Sciatic nerve conduction velocity and nerve structure were measured. The levels of MerTK, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and relevant biochemical indexes were detected. The study revealed upregulation of MerTK expression in T2DM and more so in DPN groups. Inhibiting MerTK led to reduced nerve conduction velocity and further deterioration of sciatic nerve structure, as evidenced by structural morphology. Concurrently, serum levels of total cholesterol, glycated hemoglobin, and triglyceride significantly increased. Moreover, levels of NF-κB increased in both serum and nerve tissue, alongside a significant rise in TNF-α and IL-1β expressions. MerTK could bind to the inhibitor of kappa B kinase beta (Ikbkb) in Schwann cells, establishing Ikbkb as a precursor to NF-κB activation. Inhibition of MerTK exacerbates neuropathy, indicating its protective role in DPN by suppressing the NF-κB pathway, highlighting a potential new target for its diagnosis and treatment.

The usefulness of ultrasonography for the early diagnosis of polyneuropathy in patients with type II diabetes mellitus

Background: Diabetic neuropathies, affecting over 50% of diabetes patients, present varied forms of polyneuropathy impacting somatic and autonomic nerves. Clinical assessments, laboratory findings, and nerve conduction studies (NCSs) aid in precise diagnosis, while recent technological advances highlight ultrasonography (US) as a promising, cost-effective diagnostic tool. Aims and Objectives: This study aims to assess the efficacy of US in early polyneuropathy diagnosis in type II diabetes, exploring its potential as an alternative to NCS. Materials and Methods: In this prospective observational study, we enrolled 30 adult patients with type II non-controlled diabetes and 30 age-matched controls, comprising 15 controlled diabetic patients and 15 normal individuals. The comprehensive assessments encompassed history-taking for diabetes duration, hypertension, and diabetic complications, along with clinical examinations and investigations involving nerve electrophysiology and US on one upper limb based on patient complaints. Results: Significant increases in the cross-sectional area (CSA) of the median nerve were observed in diabetic peripheral neuropathy groups compared to controls, with a P&lt;0.001. Similarly, at the level behind the medial epicondyle, the ulnar nerve CSA exhibited a significant increase in the diabetic peripheral neuropathy group (11.7 mm2) compared to controls (6.7 mm2) with a P&lt;0.002. In addition, a significant difference in cross-sectional values was found in the median nerve proximal to the carpal tunnel between the two groups (P&lt;0.05). In contrast, no significant differences were observed at other sites. Regarding the relationship between sonography and NCSs, NCSs showed higher sensitivity, but sonography demonstrated comparable specificity in evaluating diabetic peripheral neuropathy. Conclusion: Peripheral nerve US in the upper limb can be a valuable diagnostic tool for identifying and diagnosing diabetic peripheral neuropathy.

Association of vitamin D deficiency and subclinical diabetic peripheral neuropathy in type 2 diabetes patients.

Diabetic peripheral neuropathy (DPN) contributes to disability and imposes heavy burdens, while subclinical DPN is lack of attention so far. We aimed to investigate the relationship between vitamin D and distinct subtypes of subclinical DPN in type 2 diabetes (T2DM) patients. This cross-sectional study included 3629 T2DM inpatients who undertook nerve conduction study to detect subclinical DPN in Zhongshan Hospital between March 2012 and December 2019. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D (25(OH)D) level < 50 nmol/L. 1620 (44.6%) patients had subclinical DPN and they were further divided into subgroups: distal symmetric polyneuropathy (DSPN) (n=685), mononeuropathy (n=679) and radiculopathy (n=256). Compared with non-DPN, DPN group had significantly lower level of 25(OH)D (P < 0.05). In DPN subtypes, only DSPN patients had significantly lower levels of 25(OH)D (36.18 ± 19.47 vs. 41.03 ± 18.47 nmol/L, P < 0.001) and higher proportion of vitamin D deficiency (78.54% vs. 72.18%, P < 0.001) than non-DPN. Vitamin D deficiency was associated with the increased prevalence of subclinical DPN [odds ratio (OR) 1.276, 95% confidence interval (CI) 1.086-1.501, P = 0.003] and DSPN [OR 1. 646, 95% CI 1.31-2.078, P < 0.001], independent of sex, age, weight, blood pressure, glycosylated hemoglobin, T2DM duration, calcium, phosphorus, parathyroid hormone, lipids and renal function. The association between vitamin D deficiency and mononeuropathy or radiculopathy was not statistically significant. A negative linear association was observed between 25(OH)D and subclinical DSPN. Vitamin D deficiency maintained its significant association with subclinical DSPN in all age groups. Vitamin D deficiency was independently associated with subclinical DSPN, rather than other DPN subtypes.

Association of serum NF-κB levels with peripheral neuropathy in type 2 diabetes mellitus patients: a pilot study.

Hyperglycaemia-induced inflammation plays a vital role in the development of diabetic peripheral neuropathy (DPN). Recent evidences had reported the involvement of the transcription factor nuclear factor kappa-light-chain-enhancer of activated Bcell (NF-κB) in diabetic experimental models. So, this pilot study aimed to evaluate serum NF-κB levels in DPN patients. We recruited 50 T2DM patients, of which 25 were T2DM with neuropathy and 25 were T2DM without neuropathy. In all the participants peripheral neuropathy was diagnosed based on Total neuropathy score (TNS). Serum NF-κB levels were measured by ELISA. We observed that the serum NF-κB levels were higher in DPN patients in comparison to T2DM patients without neuropathy. On spearman correlation, a positive correlation was found between serum NF-κB levels and TNS in the DPN group (r=0.741, p<0.001). The regression model shows the TNS to be an independent determinant of serum NF-κB levels after adjustment for potential confounders like age, duration of diabetes, and HbA1C (B=81.34; p<0.001). NF-κB activation plays a key role in promoting inflammation which is associated with the progression of DPN. In this respect, the study of NF-κB levels in serum may be an additional diagnostic marker for DPN.

Association between phase angle and diabetic peripheral neuropathy in Type 2 diabetes patients.

Diabetic peripheral neuropathy (DPN), the very prevalent microvascular complication of type 2 diabetes mellitus (T2DM), severely threatens the quality of life of diabetic patients. Thus, prevention of DPN is extremely important for public health, and the identification of potential biomarkers may help with early prevention. Our work determined the association between phase angles (PhAs) and the risk of DPN in T2DM patients. This cross-sectional study recruited 697 T2DM patients from the Third Affiliated Hospital of Soochow University. All patients were divided into the non-diabetic peripheral neuropathy group and diabetic peripheral neuropathy group, and the DPN group was further divided into low, medium, and high diabetic foot ulcer risk groups according to vibration perception threshold results. Using univariate and multivariate logistic regression analyses continuously, the relationship between PhAs (arms, legs, trunk, and whole body) and the risk of DPN were evaluated. Further analysis was conducted on different subgroups of the study population. After adjusting for the potential covariates, multivariate logistic regression analyses indicated that PhAs of the arms, legs, and whole body correlated inversely with the risk of DPN. However, the PhA of the trunk had no significant correlation with DPN. According to the stratified subgroup analysis, the negative association between PhA of the whole body and the risk of DPN remained significant in the sex and BMI group except for participants with BMI ≥ 28 kg/m². For the first time, PhAs were acknowledged to be independently associated with DPN. Further exploration is needed to explain the findings.

Association between Angiotensin-converting Enzyme Gene Insertion/Deletion Polymorphism with Diabetic Peripheral Neuropathy and Its Importance as a Genetic Biomarker

Background: Diabetic peripheral neuropathy (DPN) is the most common microvascular complication of type 2 diabetes mellitus (T2DM) with a prevalence ranging from 18.8% to 61.9% in India. For patients with T2DM, identifying those who are at risk of developing DPN is crucial for planning and implementing secondary preventive interventions, as well as for stepping up efforts to address risk factors. Very few studies have discovered a connection between angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphisms and the onset and progression of DPN in T2DM. Objectives: The current study intends to investigate the relationship between ACE gene I/D polymorphism with T2DM and DPN subjects among the South Tamil Nadu regional population. Materials and Methods: Thirty T2DM patients with DPN, 30 T2DM patients without DPN, and 30 control (nondiabetic) subjects were enrolled in this study. DPN was diagnosed using clinical and neurophysiological evaluation. Blood samples were collected and subjected to relevant investigations including blood glucose, glycated hemoglobin, serum creatinine, and serum lipids. Polymerase chain reaction amplification was performed to genotype the DNA for ACE I/D polymorphism using specific primers. Results: The ACE genotypes were distributed as II, 17 (57%); DD, 3 (10%); and ID, 10 (33%) in control group; II, 7 (23%); DD, 11 (37%); and ID, 12 (40%) in T2DM without DPN group, II, 3 (10%); DD, 16 (53%); and ID, 11 (37%) in T2DM with DPN group. The frequency of DD genotype was significantly higher in T2DM (P = 0.03) and T2DM patients with DPN (P = 0.001) compared to controls. The DD genotype versus II genotype was found to be associated with an increased risk of DPN (odds ratio [OR] = 10.28; 95% confidence interval [CI] =2.55–41.37). The D allele was more frequent among T2DM patients with DPN (71.6%) followed by T2DM patients (56.6%) compared to controls (26.6%). The D allele (vs. the I allele) is associated with an increased risk of T2DM (OR = 3.59, 95% CI = 1.670–7.742) and DPN (OR = 6.95, 95% CI = 3.120–15.507). Conclusion: The D allele and DD genotype of the ACE gene may both be risk factors for T2DM; in fact, the D allele of this polymorphism may potentially be linked to the development of DPN in T2DM patients. This finding implies that it may be possible to prevent DPN by early detection by identifying defects in ACE I/D polymorphisms in the south Indian regional population.

Correlation study of renal function indices with diabetic peripheral neuropathy and diabetic retinopathy in T2DM patients with normal renal function.

The anticipation of diabetes-related complications remains a challenge for numerous T2DM patients, as there is presently no effective method for early prediction of these complications. This study aims to investigate the association between renal function-related indicators and the occurrence of peripheral neuropathy and retinopathy in individuals diagnosed with type 2 diabetes mellitus (T2DM) who currently have normal renal function. Patients with T2DM who met the criteria were selected from the MMC database and divided into diabetic peripheral neuropathy (DPN) and diabetic retinopathy (DR) groups, with a total of 859 and 487 patients included, respectively. Multivariate logistic regression was used to analyze the relationship between blood urea nitrogen (BUN), creatinine (Cr), uric acid (UA), urine albumin(ALB), albumin-to-creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), and diabetic peripheral neuropathy and retinopathy. Spearman correlation analysis was used to determine the correlation between these indicators and peripheral neuropathy and retinopathy in diabetes. In a total of 221 patients diagnosed with DPN, we found positive correlation between the prevalence of DPN and eGFR (18.2, 23.3, 35.7%, p < 0.05). Specifically, as BUN (T1: references; T2:OR:0.598, 95%CI: 0.403, 0.886; T3:OR:1.017, 95%CI: 0.702, 1.473; p < 0.05) and eGFR (T1: references; T2:OR:1.294, 95%CI: 0.857, 1.953; T3:OR:2.142, 95%CI: 1.425, 3.222; p < 0.05) increased, the odds ratio of DPN also increased. Conversely, with an increase in Cr(T1: references; T2:OR:0.86, 95%CI: 0.56, 1.33; T3:OR:0.57, 95%CI: 0.36, 0.91; p < 0.05), the odds ratio of DPN decreased. Furthermore, when considering sensitivity and specificity, eGFR exhibited a sensitivity of 65.2% and specificity of 54.4%, with a 95% confidence interval of 0.568-0.656. In this experimental sample, we found a clear positive correlation between eGFR and DPN prevalence.

Arginine Biosynthesis Pathway Found to Play a Key Role in the Neuroprotective Effect of Liu-Wei-Luo-Bi (LWLB) Granules in Diabetic db/db Mice with Peripheral Neuropathy Using an Untargeted Metabolomics Strategy.

Liu-Wei-Luo-Bi (LWLB) granules was a Chinese compound prescription for treating diabetic peripheral neuropathy (DPN). The aim of this study was to investigate the effect of LWLB granules on diabetic mice with peripheral neuropathy and to elucidate the potential mechanism based on an untargeted metabolomics approach. One hundred forty db/db mice were randomly divided into seven groups: the Control group, DPN group, Mudan (MD) granules group, Epalrestat (Epa) group, and the LWLB low, medium, or high dose (LW-l, LW-m, or LW-h) group. After 12 weeks of treatment, body weight, blood glucose, mechanical pain threshold, motor conduction velocity (MCV), sensory conduction velocity (SCV), and Pathological Organization of the Sciatic and Caudal Nerves in mice were measured. Serum samples were collected for untargeted metabolomics analysis using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) and multivariate statistics. Disease-related pathways were screened out with function enrichment analyses of candidate biomarkers. LWLB granules can improve the peripheral neuropathy of type 2 diabetic mice with peripheral nerve conduction disorders, mainly through significantly improving the nerve conduction velocity (P < 0.05) and lowering the mechanical pain threshold (P < 0.05). A total of 43 metabolites were identified as potential biomarkers related to the therapeutic effect of LWLB granules. Fifty, 4, and 26; 23, 4, and 22; and 24, 1, and 16 biomarkers were discovered in the LW-l, LW-m, and LW-h groups at the 4th, 6th, and 12th weeks, respectively. Five, three, seven, five, and four metabolic pathways were found in MD, Epa, LW-l, LW-m, and LW-h groups, respectively. The arginine biosynthesis pathway is the overlapping pathway in LW-l, LW-m, and LW-h groups. LWLB granules have an obvious neuroprotective effect on diabetic peripheral neuropathy, and the metabolism mechanism of LWLB is mainly related to the arginine biosynthesis pathway on diabetic db/db mice with peripheral neuropathy.

Relationship among serum TIMP-1, sCD40L and peripheral neuropathy in type 2 diabetes

Purpose: To determine the correlation of serum TIMP-1 and sCD40L with peripheral neuropathy in type 2 diabetes (T2DM), and potential targets for pharmacological intervention.Methods: The study enrolled 97 subjects with T2DM. The 41 subjects with simple diabetes were classified as T2DM group, while 56 subjects with diabetic peripheral neuropathy (DPN) were included in the DPN group. A control group consisting of 50 healthy volunteers who conducted health checks during a similar time-period was also included. Clinical data and parameters were compared among the three groups, and TIMP-1 and sCD40L levels were determined. Univariate and multivariate logistic regression analyses were conducted to identify factors affecting DPN. The diagnostic value of TIMP-1 and sCD40L in DPN was also determined.Results: Body mass index (BMI) varied among the three groups (p &lt; 0.05), but age or gender were not significantly different (p &lt; 0.05). Duration of diabetes was longer in DPN group than in T2DM group (p &lt; 0.05). The study also revealed statistically significant differences in fasting blood glucose (FBS), postprandial blood glucose, and glycosylated hemoglobin among the three groups. Tissue inhibitor of metalloproteinase-1 (TIMP-1) and soluble CD40 ligand (sCD40L) were important factors that affected the occurrence of diabetic peripheral neuropathy (p &lt; 0.05).Conclusion: TIMP-1 and sCD40L levels reflect neurovascular injury in patients with diabetes, with potential as targets for pharmacological intervention for peripheral neuropathy. These findings espouse crucial clinical implications for early identification and treatment in type 2 diabetes.

Formate Might Be a Novel Potential Serum Metabolic Biomarker for Type 2 Diabetic Peripheral Neuropathy.

As one of the most frequent complications of type 2 diabetes mellitus (T2DM), diabetic peripheral neuropathy (DPN) shows a profound impact on 50% of patients with symptoms of neuropathic pain, numbness and other paresthesia. No valid serum biomarkers for the prediction of DPN have been identified in the clinic so far. This study is to investigate the potential serum biomarkers for DPN firstly based on 1H-Nuclear Magnetic Resonance (1H-NMR)-based metabolomics technique. Thirty-six patients enrolled in this study were divided into two groups: 18 T2DM patients without DPN (T2DM group) and 18 T2DM patients with DPN (DPN group). Serum metabolites were measured via 1H-NMR spectroscopy. Bioinformatic approaches including principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), independent sample t-test, Fisher's test, Pearson and Spearman correlation analysis, Stepwise multiple linear regression analysis and receiver operating characteristic (ROC) curve analysis were used to identify the potential altered serum biomarkers. A total of 20 metabolites were obtained and further analyzed. Formate was identified as the only potential biomarker that decreased in the DPN group with statistical significance after multiple comparisons (p<0.05). Formate also displayed a negative relationship with some elevated clinical markers in DPN. ROC curve analysis showed a good discriminative ability for formate in DPN with an area under the curve (AUC) value of 0.981. Formate could be considered a potential serum metabolic biomarker for DPN. The reduced level of formate in DPN may be associated with mitochondrial dysfunction and gut microbiota alteration. Monitoring the level of serum formate would be an important strategy for the early diagnosis of DPN and a supplement of formate may be a promising treatment for DPN in the future.

Correlation Between Fibrinogen/Albumin and Diabetic Peripheral Neuropathy.

This study aimed to examine the correlation between fibrinogen/albumin (FAR) and diabetic peripheral neuropathy (DPN). A total of 342 patients were included and categorized into either the DPN group or the Non-DPN (NDPN) group based on their DPN status. The FAR index was determined by calculating the ratio of fibrinogen (FIB) to serum albumin (ALB), multiplied by 100. The participants were then divided into a High-FAR group and a Low-FAR group using the median FAR value as the threshold. Neurophysiological data were collected from the participants, which included motor conduction velocity (MCV) and sensory conduction velocity (SCV). The DPN group displayed higher FAR levels [(DPN vs NDPN:6.72 (5.89,7.74) vs 5.94±1.14], in addition to slower SCV and MCV data compared to the NDPN group. The high FAR group had a higher prevalence of DPN (78.9% vs 55.6%) (P<0.05). There was a negative correlation between FAR and NCV, including bilateral median nerve SCV, left ulnar nerve SCV, bilateral median nerve MCV, bilateral common peroneal nerve MCV, bilateral tibial nerve MCV, and left ulnar nerve MCV. FAR was revealed to be an independent risk factor for the development of DPN in patients and demonstrated a greater predictive value for DPN development in Type 2 diabetes mellitus (T2DM) compared with FIB, HbA1c. The results suggest that monitoring FAR levels in patients with T2DM could identify those at higher risk for developing DPN, making the FAR index a valuable predictor of DPN development. Furthermore, since FAR has an inverse relationship with NCV, it stands to reason that high FAR levels may indicate nerve damage and slower conduction velocities. Thus, managing FAR could prove beneficial in both preventing and delaying the onset of DPN in T2DM patients.

Early detection of diabetic peripheral neuropathy using EMLA-induced skin wrinkling

Background &amp; Objective: Screening for early diabetic peripheral neuropathy (DN) is essential for foot ulcer prevention. The Semmes–Weinstein monofilament (SWMF) is commonly used to detect DN in Thailand. However, SWMF interpretation requires patient participation, which is susceptible to risk of error in patients with impaired cognitive function or uncooperative patients. In contrast, stimulated skin wrinkling (SSW) can be interpreted by trained investigators, which is more appropriate. This study aimed to investigate the utility of SSW using a eutectic mixture of local anesthetic (SSW-EMLA) for early DN diagnosis. Methods: This cross-sectional study, recruited 102 patients with diabetes (DM group), 33 with diabetes with foot ulcer (DN control group), and 30 without diabetes (non-DN control group) from the Faculty of Medicine, Vajira Hospital, Navamindradhiraj University, Thailand, from February 3, 2021 to November 30, 2021. SSW was conducted by applying EMLA on the tips of the 2nd, 3rd, and 4th fingers of both hands. SWMF, sensory perception of pain (SPP), vibration perception threshold (VPT), joint position sense (JPS), and deep tendon reflexes (DTR) were also evaluated on the same day. Results: The Interrater agreement of two investigators for SSW-EMLA was high with intraclass correlation coefficients of 0.87 (0.824–0.904) for the right hand and 0.874 (0.830–0.907) for the left hand. The kappa coefficients of agreement of SSW-EMLA for SPP, SWMF, VPT, JPS, and DTR testing were 0.411, 0.478, 0.714, 0.444, and 0.681, respectively. The sensitivity and specificity of SSW-EMLA testing for DN detection were 83.3%, was 85.7%, respectively. Conclusion: The SSW-EMLA test can be considered as an alternative method for DN detection, due to its noninvasiveness, inexpensiveness (50THB), being a simple procedure, high sensitivity and specificity, and acceptable rater variation.

The association of vitamin D level with diabetic peripheral neuropathy: A comparative cross- sectional study

Background &amp; Objective: Diabetic peripheral neuropathy (DPN) is a common complication of type 2 diabetes mellitus (DM). Vitamin D deficiency has been shown to be prevalent among patients with type 2 DM, particularly in those with DPN. This study aimed to look at the association of serum vitamin D level with peripheral neuropathy in patients with type 2 DM. Methods: This was a comparative cross- sectional study conducted in a tertiary hospital in Malaysia. Fifty diabetic patients with DPN and fifty diabetic patients without DPN were recruited. Serum vitamin D level was determined by measuring 25-hydroxyvitamin D [25(OH)D] level. The patients were clinically assessed and screened with Diabetic Neuropathy Symptoms score. Nerve conduction study was performed for patients with DPN. Results: The serum 25(OH)D level was significantly lower in patients with DPN (11.81 [9.09-18.06] vs 18.63 [11.25-22.63] ng/ml; p=0.006). Multiple logistic regression analysis showed that DPN was significantly associated with higher BMI, longer duration of DM, insulin usage and serum 25(OH)D level. The usage of fibrates had negative association with DPN. Subgroup analysis of the DPN group showed that patients with painful DPN had significant lower serum 25(OH)D level (p&lt;0.001) and the clinical severity of DPN negatively correlated with serum 25(OH)D level (p=0.015). Conclusion: Vitamin D deficiency is associated with DPN in patients with type 2 DM. In addition, patients with painful DPN tend to have significantly lower serum 25(OH)D level.

Ultrasound characteristics of the cervical vagus nerve in patients with type 2 diabetes and diabetic peripheral neuropathy.

Diabetic peripheral neuropathy (DPN) and autonomic neuropathy are commonly coexistent in patients with type 2 diabetes mellitus (T2DM). Current assessment tools for diabetic neuropathy remain complicated and limited. We aimed to investigate the sonographic changes of the cervical vagus nerve in DPN patients with T2DM. Patients with T2DM were divided into a DPN group (DPN, n = 44) and non-DPN controls (NDPN, n = 43) based on electromyogram results. Another 43 healthy controls (CON) were included. High-frequency ultrasound (HFU) of the vagus nerve was performed in all participants. Compared with controls, the honeycomb structure of the vagus nerve in patients with T2DM decreased, p < 0.001. The DPN group had higher cross-sectional area (CSA) of the right vagus nerve than the NDPN group (1.60 ± 0.52 vs. 2.00 ± 0.57 mm2, p =0.001). Logistic regression showed that right vagus nerve CSA was a risk factor of DPN (odds ratio [OR] = 3.924, p = 0.002). Right vagus nerve CSA was positively correlated with diabetes duration (p = 0.003), and negatively correlated with the motor conduction velocity (MCV) of the ulnar, median, and common peroneal nerves (p < 0.001 for all), as well as the sensor conduction velocity (SCV) of the ulnar and median nerve (both p < 0.005). HFU shows thickening of the cervical vagus nerve in patients with DPN, which is a potential diagnostic feature of diabetic neuropathy.

Association between serum asprosin and diabetic peripheral neuropathy in patients with type 2 diabetes mellitus in the community.

This study aimed to investigate the relationship between serum asprosin level and diabetic peripheral neuropathy (DPN) in community patients with type 2 diabetes mellitus (T2DM). A total of 498 patients with T2DM were recruited from Zhuoma Community Health Service Station and Chengbei West Street Community Health Service Center in Changzhi City of Shanxi Province between November 2019 and July 2021. Their height, weight, and body mass index (BMI), as well as fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), triglyceride (TG), and serum asprosin levels, were analyzed. Patients were divided into the DPN group (n = 329) and the non-DPN group (n = 169) according to the presence or absence of DPN. The t-test, Mann-Whitney U test, and χ² test were used to compare the indicators between the two groups. Pearson or Spearman correlation analysis was used to evaluate the correlation between serum asprosin and other clinical data. Multivariate logistic regression analysis was used to analyze the influencing factors of DPN. Compared with the non-DPN group, the DPN group had higher serum asprosin (p < 0.05). The prevalence of DPN gradually increased according to the tertiles of asprosin (56%, 67%, and 75%; p < 0.05). Multivariate logistic regression analysis showed that after adjustment for covariates, patients with asprosin concentrations between 295.4-367.0 pg/ml and concentrations > 367.0 pg/ml had a higher risk of diabetic neuropathy compared than those with asprosin levels < 295.4 pg/ml (p < 0.05). Serum asprosin was found to be positively correlated with DPN, and it resulted as an influencing factor for DPN in patients with T2DM in the community. With the increase of asprosin, the risk of DPN also increased.

Effect of 10.6 μm laser moxibustion on inflammation in diabetic peripheral neuropathy rats.

Diabetic peripheral neuropathy (DPN) is the main cause of disability in diabetes patients but the efficacy of available drugs is poor. Moxibustion is an adjunctive treatment for DPN that can reduce symptoms. The peak value of the far infrared wavelength of 10.6 μm laser moxibustion is close to the infrared radiation spectrum of traditional moxibustion. Its effect is similar to that of moxibustion and does not cause pain, infection or produce irritating smoke. Twenty-four male SD rats were divided into control (Con), DPN, laser moxibustion (LM), and pyrrolidine dithiocarbamate (PDTC) groups (n=6/group). The DPN, LM and PDTC group rats were intraperitoneally injected with 1% streptozotocin (STZ) to induce a model of DPN. LM group rats were irradiated with a laser at bilateral ST36 acupoints for 15min, once every other day, for 14 days. PDTC group rats were intraperitoneally injected with PDTC once a day. Body weight, blood glucose, and paw withdrawal mechanical threshold (PWMT) were measured and laser speckle imaging (LSI) performed before and after modeling and at 1 and 2 weeks after intervention. Two weeks after intervention, changes in serum interleukin 1β (IL1β), interleukin 6 (IL6), tumor necrosis factor α (TNFα) and nerve growth factor (NGF) were analyzed, and the abundance of NF-κB and IκB-α proteins and levels of NF-κB and IκB-α mRNAs in the sciatic nerve were observed. The results showed that 10.6 μm laser moxibustion can relieve pain, improve microcirculation, and alleviate inflammation in DPN rats, possibly via the NF-κB inflammatory pathway.

Effect of joint limitation and balance control on gait changes in diabetic peripheral neuropathy.

This study analyzed the gait patterns of diabetic peripheral neuropathy (DPN) patients and changes in the center of mass sway to prevent the formation and recurrence of foot ulcers. Forty-two subjects were divided into the diabetes mellitus (DM), DPN, and diabetic foot ulcer (DFU) groups. We measured the range of motion (ROM) of the lower limb joints in the resting position and the center of mass sway in the standing position. Joint angles, ROM during walking, and distance factors were evaluated. In the DFU group, ROM limitation during walking was detected at the knee joint, and functional and ROM limitations were found at the ankle joint. The step length ratio and step width in the DFU group were significantly lower and higher than those in the DM group, respectively. The sway distances in the DFU group were greater than those in the DM and DPN groups. Functional joint limitations and gait changes due to the decreased ability to maintain the center of gravity were observed in the DFU group. As DPN progressed, the patients' gait became small, wide, and shuffled. Thus, supporting joint movement during walking may help reduce the incidence and recurrence of foot ulcers. The online version contains supplementary material available at 10.1007/s13340-023-00647-9.

Role of Fibrinogen in Type-2 Diabetes Mellitus with Diabetic Neuropathy and its Preliminary Mechanism.

Diabetic peripheral neuropathy (DN) is the most common complication of type 2 diabetes mellitus (T2DM). This study aimed to explore the role of fibrinogen (FIB) in T2DM neuropathy and its preliminary mechanism. Ten male Sprague-Dawley rats were divided into a normal control group (NC group) and a T2DM neuropathy model group (DN group). The DN group was given a high-energy diet and streptozotocin, while the NC group was given a normal diet and a citric acid buffer. The expression levels of related proteins were analysed. Electrophysiology: Compared with the NC group, the conduction latency of the somatosensory-evoked potential and nerve conduction velocity was prolonged in the DN group, while the motor nerve action potential was decreased. As seen under a light microscope, the peripheral nerve fibres in the DN group were swollen, and the nerve fibres in the posterior funiculus of the spinal cord were loose or missing. Moreover, as seen under an electron microscope, the peripheral nerve demyelination of the DN group was severe, with microvascular blood coagulation, luminal stenosis, and collapse. Compared with the NC group, in the DN group, the expression of FIB was positively correlated with the expression of both ionised calcium-binding adaptor molecule-1 and glial fibrillary acidic protein. Compared with the NC group, in the DN group, the expression of platelet/endothelial cell adhesion molecule-1 and B-cell lymphoma 2 was negatively correlated. The increased concentration of FIB may be the cause of neuropathy, and its mechanism may be related to its promotion of inflammatory response, blood coagulation, and vascular stenosis.