Circulating metabolomic markers in association with overall burden of microvascular complications in type 1 diabetes.

INTRODUCTION: Diabetic retinopathy (DR), diabetic kidney disease (DKD) and distal symmetric polyneuropathy (DSPN) share common pathophysiology and pose an additive risk of early mortality. RESEARCH DESIGN AND METHODS: In adults with type 1 diabetes, 49 metabolites previously associated with either DR or DKD were assessed in relation to presence of DSPN. Metabolites overlapping in significance with presence of all three complications were assessed in relation to microvascular burden severity (additive number of complications-ie, presence of DKD±DR±DSPN) using linear regression models. Subsequently, the same metabolites were assessed with progression to endpoints: soft microvascular events (progression in albuminuria grade, ≥30% estimated glomerular filtration rate (eGFR) decline, or any progression in DR grade), hard microvascular events (progression to proliferative DR, chronic kidney failure, or ≥40% eGFR decline), and hard microvascular or macrovascular events (hard microvascular events, cardiovascular events (myocardial infarction, stroke, or arterial interventions), or cardiovascular mortality), using Cox models. All models were adjusted for sex, baseline age, diabetes duration, systolic blood pressure, HbA1c, body mass index, total cholesterol, smoking, and statin treatment. RESULTS: The full cohort investigated consisted of 487 participants. Mean (SD) follow-up was 4.8 (2.9, 5.7) years. Baseline biothesiometry was available in 202 participants, comprising the cross-sectional cohort. Eight metabolites were significantly associated with presence of DR, DKD, and DSPN, and six with additive microvascular burden severity. In the full cohort longitudinal analysis, higher levels of 3,4-dihydroxybutanoic acid (DHBA), 2,4-DHBA, ribonic acid, glycine, and ribitol were associated with development of events in both crude and adjusted models. Adding 3,4-DHBA, ribonic acid, and glycine to a traditional risk factor model improved the discrimination of hard microvascular events. CONCLUSIONS: While prospective studies directly assessing the predictive ability of these markers are needed, our results strengthen the role of clinical metabolomics in relation to risk assessment of diabetic complications in chronic type 1 diabetes.

Risk factors for erectile dysfunction in diabetes mellitus: a systematic review and meta-analysis.

Background: Previous studies have established that diabetes mellitus (DM) markedly raises the risk of developing erectile dysfunction (ED). Despite extensive investigations, the risk factors associated with ED in diabetic men have yet to be unequivocally determined, owing to incongruent and inconclusive results reported in various studies. Objective: The objective of this systematic review and meta-analysis was to assess the risk factors for ED in men with DM. Methods: A comprehensive systematic review was conducted, encompassing studies published in the PubMed, Scopus and Embase databases up to August 24th, 2023. All studies examining the risk factors of ED in patients with DM were included in the analysis. To identify significant variations among the risk factors, odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were employed. The risk of bias was evaluated using the Newcastle-Ottawa Scale(NOS) for longitudinal studies and the Agency for Healthcare Research and Quality Scale(AHRQ) for cross-sectional studies. Results: A total of 58 studies, including a substantial participant pool of 66,925 individuals diagnosed with DM, both with or without ED, were included in the meta-analysis. Mean age (OR: 1.31, 95% CI=1.24-1.37), smoking status (OR: 1.32, 95% CI=1.18-1.47), HbA1C (OR: 1.44, 95% CI=1.28-1.62), duration of DM (OR: 1.39, 95% CI=1.29-1.50), diabetic neuropathy (OR: 3.47, 95% CI=2.16-5.56), diabetic retinopathy (OR: 3.01, 95% CI=2.02-4.48), diabetic foot (OR: 3.96, 95% CI=2.87-5.47), cardiovascular disease (OR: 1.92, 95% CI=1.71-2.16), hypertension (OR: 1.74, 95% CI=1.52-2.00), microvascular disease (OR: 2.14, 95% CI=1.61-2.85), vascular disease (OR: 2.75, 95% CI=2.35-3.21), nephropathy (OR: 2.67, 95% CI=2.06-3.46), depression (OR: 1.82, 95% CI=1.04-3.20), metabolic syndrome (OR: 2.22, 95% CI=1.98-2.49), and diuretic treatment (OR: 2.42, 95% CI=1.38-4.22) were associated with increased risk factors of ED in men with DM. Conclusion: Our study indicates that in men with DM, several risk factors for ED have been identified, including mean age, HbA1C, duration of DM, diabetic neuropathy, diabetic retinopathy, diabetic foot, cardiovascular disease, hypertension, microvascular disease, vascular disease, nephropathy, depression, metabolic syndrome, and diuretic treatment. By clarifying the connection between these risk factors and ED, clinicians and scientific experts can intervene and address these risk factors, ultimately reducing the occurrence of ED and improving patient management.

A muscarinic receptor antagonist reverses multiple indices of diabetic peripheral neuropathy: preclinical and clinical studies using oxybutynin.

Preclinical studies indicate that diverse muscarinic receptor antagonists, acting via the M1 sub-type, promote neuritogenesis from sensory neurons in vitro and prevent and/or reverse both structural and functional indices of neuropathy in rodent models of diabetes. We sought to translate this as a potential therapeutic approach against structural and functional indices of diabetic neuropathy using oxybutynin, a muscarinic antagonist approved for clinical use against overactive bladder. Studies were performed using sensory neurons maintained in vitro, rodent models of type 1 or type 2 diabetes and human subjects with type 2 diabetes and confirmed neuropathy. Oxybutynin promoted significant neurite outgrowth in sensory neuron cultures derived from adult normal rats and STZ-diabetic mice, with maximal efficacy in the 1-100 nmol/l range. This was accompanied by a significantly enhanced mitochondrial energetic profile as reflected by increased basal and maximal respiration and spare respiratory capacity. Systemic (3-10 mg/kg/day s.c.) and topical (3% gel daily) oxybutynin reversed paw heat hypoalgesia in the STZ and db/db mouse models of diabetes and reversed paw tactile allodynia in STZ-diabetic rats. Loss of nerve profiles in the skin and cornea of db/db mice was also prevented by daily topical delivery of 3% oxybutynin for 8 weeks. A randomized, double-blind, placebo-controlled interventional trial was performed in subjects with type 2 diabetes and established peripheral neuropathy. Subjects received daily topical treatment with 3% oxybutynin gel or placebo for 6 months. The a priori designated primary endpoint, significant change in intra-epidermal nerve fibre density (IENFD) in skin biopsies taken before and after 20 weeks of treatments, was met by oxybutynin but not placebo. Secondary endpoints showing significant improvement with oxybutynin treatment included scores on clinical neuropathy, pain and quality of life scales. This proof-of-concept study indicates that muscarinic antagonists suitable for long-term use may offer a novel therapeutic opportunity for treatment of diabetic neuropathy. Trial registry number: NCT03050827.

The Difference Between Cystatin C- and Creatinine-Based Estimated Glomerular Filtration Rate and Risk of Diabetic Microvascular Complications Among Adults With Diabetes: A Population-Based Cohort Study.

OBJECTIVE: The impact of the difference between cystatin C- and creatinine-based estimated glomerular filtration rate (eGFRdiff) on diabetic microvascular complications (DMCs) remains unknown. We investigated the associations of eGFRdiff with overall DMCs and subtypes, including diabetic retinopathy (DR), diabetic kidney disease (DKD), and diabetic neuropathy (DN). RESEARCH DESIGN AND METHODS: This prospective cohort study included 25,825 participants with diabetes free of DMCs at baseline (2006 to 2010) from the UK Biobank. eGFRdiff was calculated using both absolute difference (eGFRabdiff) and the ratio (eGFRrediff) between cystatin C- and creatinine-based calculations. Incidence of DMCs was ascertained using electronic health records. Cox proportional hazards regression models were used to evaluate the associations of eGFRdiff with overall DMCs and subtypes. RESULTS: During a median follow-up of 13.6 years, DMCs developed in 5,753 participants, including 2,752 cases of DR, 3,203 of DKD, and 1,149 of DN. Each SD decrease of eGFRabdiff was associated with a 28% higher risk of overall DMCs, 14% higher risk of DR, 56% higher risk of DKD, and 29% higher risk of DN. For each 10% decrease in eGFRrediff, the corresponding hazard ratios (95% CIs) were 1.16 (1.14, 1.18) for overall DMCs, 1.08 (1.05, 1.11) for DR, 1.29 (1.26, 1.33) for DKD, and 1.17 (1.12, 1.22) for DN. The magnitude of associations was not materially altered in any of the sensitivity analyses. CONCLUSIONS: Large eGFRdiff was independently associated with risk of DMCs and its subtypes. Our findings suggested monitoring eGFRdiff in the diabetes population has potential benefit for identification of high-risk patients.

Pain exacerbation following physical activity in adults with diabetic neuropathy: Ecological momentary assessment of foot symptoms.

BACKGROUND AND OBJECTIVES: People with diabetic peripheral neuropathy (DPN) report fluctuating foot symptoms. This study used ecological momentary assessment to: (1) compare foot symptoms between days, time points and periods with/without preceding physical activity or pain medication; and (2) determine relationships between symptoms and endogenous pain modulation. METHOD: Ten low-active Australian adults with probable DPN underwent temporal summation of pain (TSP) and conditioned pain modulation (CPM) then completed mobile phone surveys five times daily for seven days, where they recorded the intensity of six foot symptoms and whether they performed physical activity or consumed pain medication in the preceding three hours.  RESULTS: All foot symptoms except numbness were greater in periods following physical activity, whereas periods following pain medication showed greater shooting pain. TSP showed very large correlations with sensitivity to touch, burning pain, shooting pain and prickling/tingling.  DISCUSSION: General practitioners should be aware that physical activity might exacerbate symptoms of DPN when encouraging their patients to be active.

Bruns Garland Syndrome as the first presentation of type 2 diabetes: two case reports and a practical approach to diagnosis.

BACKGROUND: Diabetes is a global health problem causing a significant burden on the healthcare systems both due to the disease itself and associated complications. Diabetic radiculoplexus neuropathies or Bruns-Garland syndrome constitutes a rare form of microvascular complications, more commonly affecting the lumbosacral plexus and, very rarely, the cervical plexus. We describe two Sri Lankan males who presented with diabetic lumbosacral radiculoplexus neuropathy and diabetic cervical radiculoplexus neuropathy as the initial manifestation of diabetes. CASE DESCRIPTION: Case 1: a 49-year-old Sri Lankan hotel chef presented with subacute painful weakness and wasting of the left upper arm for 3 months and weight loss. Left upper limb proximal muscles were wasted with diminished power and reflexes. A nerve conduction study showed comparative amplitude reduction. An electromyogram revealed positive sharp waves, frequent fibrillations, and high amplitude polyphasic motor unit potentials with reduced recruitment in proximal muscles of left upper limb. Case-2: a 47-year-old Sri Lankan carpenter presented with subacute progressive asymmetrical painful weakness and wasting of bilateral thighs for 5 months and weight loss. Lower limb proximal muscles were wasted with reduced power and knee jerks. The nerve conduction study was normal. The electromyogram was similar to case 1 involving both quadratus femoris muscles, which was more prominent on the left side. The work up for an underlying etiology revealed only elevated fasting blood glucose and HbA1c, suggesting a new diagnosis of diabetes associated with neurological symptoms. Patient 1 was diagnosed with diabetic cervical radiculoplexus neuropathy and patient 2 with diabetic lumbosacral radiculoplexus neuropathy. Both showed significant improvement following optimization of glycemic control together with symptomatic treatment and physiotherapy. CONCLUSION: Diagnosis of diabetic radiculoplexus neuropathy requires a comprehensive workup to rule out other sinister pathologies. This case report has a dual importance; it describes diabetic radiculoplexus neuropathy as the very first manifestation of two previously healthy people, giving rise to a new diagnosis of diabetes and, at the same time, reporting on diabetic cervical radiculoplexus neuropathy, which is extremely rare and has never been previously reported in Sri Lanka.

No clear evidence of neuropathy among patients with high risk for the development of prediabetes/diabetes-a pilot study.

Introduction: Autonomic and sensory neuropathy have been observed in both prediabetes and manifest diabetes mellitus. However, there is a lack of available data regarding whether patients at a moderate or high risk of developing diabetes, yet without a current diagnosis of prediabetes or diabetes, exhibit an increased prevalence of neuropathy. Methods: FINDRISC (Finnish Diabetes Risk Score) was used to classify individuals at risk (≥12 points, n = 44; control <12 points, n = 28). HbA1c levels >5.6% served as exclusion criteria, and patients with known medical conditions predisposing to neuropathy were also excluded. Cardiac autonomic function (Ewing tests) and peripheral sensory neuropathy (Neurometer and Q-sense) were assessed by standardized protocols, and their potential association with increased FINDRISC points was analyzed using a regression model. Results: Mean age was 46.7 ± 14.3 years in the control and 55.7 ± 14.1 years in the increased risk group. Male/female ratio did not differ. Individuals with increased risk of diabetes were more obese (BMI: 29.9 ± 12.5 kg/m2 vs. 25.9 ± 8.9 kg/m2). Additionally, hypertension was more frequent among them (68.2% vs. 17.9%), and their lipid parameters were also less favorable. Parasympathetic neuropathy was present in both groups (56.8% vs. 32.1%, respectively). Sympathetic neuropathy was not found. Sensory nerve dysfunction was of low prevalence in the high-risk group and did not occur in healthy controls. In multiple logistic regression analysis, HbA1c exhibited an independent association with parasympathetic neuropathy (OR: 5.9; 95% CI: 1.08-32.68; p < 0.041). Discussion: An increased risk of developing prediabetes/diabetes does not appear to have a strong correlation with an increased likelihood of developing autonomic or sensory neuropathy. However, the etiology behind the occurrence of parasympathetic autonomic neuropathy in healthy individuals remains unknown.

Diabetic peripheral neuropathy among adult type 2 diabetes patients in Adama, Ethiopia: health facility-based study.

Diabetic peripheral neuropathy is the most prominent microvascular complication of diabetes mellitus and the leading cause of ulceration, amputation, and extended hospitalization. Evidence regarding the magnitude and factors associated with diabetic peripheral neuropathy is not well documented in Ethiopia, particularly in the study area. A facility-based cross-sectional study was conducted among 293 adult type 2 diabetic patients who were on treatment and follow-up from May to June 31, 2023. To select participants in the study, a systematic random sampling method was utilized. Data were collected using semi-structured questionnaires and medical record reviews. The Michigan Neuropathy Screening Instrument (MNSI) was employed to assess diabetic peripheral neuropathy. To model the association between diabetic peripheral neuropathy and independent variables, binary logistic regression model was used. An adjusted odds ratio with a 95% confidence interval was used to estimate the association and statistical significance was proclaimed at a p-value < 0.05. The magnitude of diabetic peripheral neuropathy was 14.3% (95% CI 10.4-18.0). It was 13.4% (95% CI 8.4-19.1) among males and 15.4% (95% CI 10.1-22.2) among females. Age above 60 years (AOR = 5.06, 95% CI 1.60-15.96), being rural resident (AOR = 2.41; 95% CI 1.15-5.06), duration of diabetes above 5 years (AOR = 2.48, 95% CI 1.16-5.27) and having comorbid hypertension (AOR = 2.56, 95% CI 1.24-5.28) were independently associated with diabetic peripheral neuropathy. One in seven adult type 2 diabetes patients in the study area had diabetic peripheral neuropathy. Factors such as age, place of residence, duration of diabetes, and comorbid hypertension showed positive associations with diabetic peripheral neuropathy. Thus, it is imperative to give special consideration to diabetic patients who are elderly, living in rural areas, experiencing a prolonged duration of diabetes, or dealing with comorbid hypertension.

A gluco-mindful approach to diabetic gastroparesis.

Diabetes gastroparesis is a common manifestation of autonomic neuropathy in persons with long-standing, uncontrolled diabetes. Most discussion about its management revolves around the mitigation of symptoms. Here, we share tips on choosing the right glucose-lowering medication, based upon predominant symptomatology of gastroparesis. We highlight about insulin preparations, and their timing of administration, can be tailored according to need. We also emphasize the need to choose oral glucose lowering drugs with care.

Integrated genetic analysis of diabetic complications: Bioinformatics insights into foot ulcers, neuropathy and peripheral artery disease.

Diabetic foot ulcers (DFU), diabetic peripheral neuropathy (DPN) and peripheral arterial disease (PAD) are common complications of diabetes mellitus, while diabetic peripheral neuropathy and peripheral arterial disease contribute to the pathogenesis of diabetic foot ulcers, and the pathogenic mechanisms between these three diseases still need further investigation. The keywords 'diabetic foot ulcer', 'diabetic peripheral neuropathy' and 'atherosclerosis' were used to search for related gene sets in the GEO database. Differentially expressed genes (DEGs) were screened and analysed for GO, KEGG and enrichR functional enrichment. Potential three disease biomarkers were identified by SVM-SVM-RFE and LASSO regression analysis. The results were also validated using external datasets and discriminability was measured by area under the ROC curve (AUC). Finally, biomarkers and co-upregulated genes were analysed through the GSEA and Attie Laboratories diabetes databases. A total of 11 shared genes (KRT16, CD24, SAMD9L, SRGAP2, FGL2, GPR34, DDIT4, NFE2L3, FBLN5, ANXA3 and CPA3), two biomarkers (SAMD9L and FGL2) and one co-upregulated gene (CD24) were screened. GO and KEGG pathway analysis of DEGs, enrichr enrichment analysis of shared differential genes and GSEA analysis of biomarkers showed that these significant genes were mainly focused on vasoregulatory, inflammatory-oxidative stress and immunomodulatory pathways. In this study, we used bioinformatics to investigate the intrinsic relationship and potential mechanisms of three common lower extremity complications of diabetes and identified two pivotal genes using the LASSO model and the SVM-RFE algorithm, which will further help clinicians to understand the relationship between diabetic complications, improve the diagnosis and treatment of diabetic foot problems and help doctors to identify the potential risk factors of diabetic foot.

New concepts drive the development of delivery tools for sustainable treatment of diabetic complications.

Diabetic complications, especially diabetic retinopathy, diabetic nephropathy and painful diabetic neuropathy, account for a large portion of patients with diabetes and display rising global prevalence. They are the leading causes of blindness, kidney failure and hypersensitivity to pain caused by diabetes. Current approved therapeutics against the diabetic complications are few and exhibit limited efficacy. The enhanced cell-specificity, stability, biocompatibility, and loading capacity of drugs are essential for the mitigation of diabetic complications. In the article, we have critically discussed the recent studies over the past two years in material sciences and biochemistry. The insightful concepts in these studies drive the development of novel nanoparticles and mesenchymal stem cells-derived extracellular vesicles to meet the need for treatment of diabetic complications. Their underlying biochemical principles, advantages and limitations have been in-depth analyzed. The nanoparticles discussed in the article include double-headed nanodelivery system, nanozyme, ESC-HCM-B system, soft polymer nanostars, tetrahedral DNA nanostructures and hydrogels. They ameliorate the diabetic complication through attenuation of inflammation, apoptosis and restoration of metabolic homeostasis. Moreover, mesenchymal stem cell-derived extracellular vesicles efficiently deliver therapeutic proteins to the retinal cells to suppress the angiogenesis, inflammation, apoptosis and oxidative stress to reverse diabetic retinopathy. Collectively, we provide a critical discussion on the concept, mechanism and therapeutic applicability of new delivery tools to treat these three devastating diabetic complications.

Gastroparesis might not be uncommon in patients with diabetes mellitus in a real-world clinical setting: a cohort study.

BACKGROUND: This study investigated the frequency of diabetic gastroparesis and associated risk factors in a real-world clinical setting. METHODS: This retrospective cross-sectional study included patients who underwent assessments of solid gastric emptying time (GET) by technetium-99 m scintigraphy between May 2019 and December 2020. We categorized patients into three groups according to gastric retention of technetium-99 m: rapid (< 65% at 1 h or < 20% at 2 h), normal (≤60% at 2 h and/or ≤ 10% at 4 h), and delayed (> 60% at 2 h and/or > 10% at 4 h). RESULTS: Patients with diabetes mellitus (DM) were more likely to show abnormal GET than those without DM (119 [70.8%] vs. 16 [44.4%]). The mean glycated A1c was 10.3% in DM patients. DM patients with normal GET were significantly younger (57.2 years, P = 0.044) than those with delayed (65.0 years) or rapid GET (60.2 years). Fasting glucose levels were the lowest in the normal GET group and the highest in the rapid GET group (delayed: 176.3 mg/dL, normal: 151.2 mg/dL, rapid: 181.0 mg/dL, P = 0.030). However, glycated A1c was not significantly different among the delayed, normal, and rapid GET groups in patients with DM. Patients with delayed and rapid GET showed a higher frequency of retinopathy (6.0 vs. 15.5%, P = 0.001) and peripheral neuropathy (11.3 vs. 24.4%, P = 0.001) than those with normal GET. In the multinomial logistic regression analysis, retinopathy demonstrated a positive association with delayed GET, while nephropathy showed a significant negative correlation. CONCLUSION: DM gastroparesis in the clinical setting was not uncommon. Abnormal GET, including delayed and rapid GET, was associated with DM retinopathy or peripheral neuropathy.

Nerve Decompression in the Lower Leg Results in an Improvement in Symptoms in Patients With Both Diabetic and Idiopathic Polyneuropathy.

BACKGROUND: Patients suffering from polyneuropathy often complain of pain, tingling, and numbness sensations, as well as an increased risk of falling with the corresponding subsequent complications. If symptoms persist after conservative treatment options have been exhausted, nerve decompression in the lower extremity, as described by Dellon, can bring about an improvement in symptoms in many patients. Dellon originally reported that this surgery led to very successful outcomes in patients with diabetic polyneuropathy. In this study, we compare our postsurgical results in patients with diabetic versus idiopathic polyneuropathy. METHODS: Thirty-three patients with idiopathic or diabetic polyneuropathy who had undergone Dellon nerve decompression in the lower extremity between 2011 and 2013 were included in the retrospective study. Pain (numeric rating scale [NRS] 0-10; 0, no pain; 10, worst imaginable pain), tingling, numbness, Hoffmann-Tinel sign, and Semes-Weinstein monofilament were assessed in 20 patients with diabetic polyneuropathy and in 13 patients with idiopathic polyneuropathy. RESULTS: Three months after surgery, a significant reduction in pain was evident in patients with diabetic polyneuropathy, from a preoperative level of NRS 4.9 (minimum, 0; maximum, 10) to 2 (minimum, 0; maximum, 8; P = 0.005). Ninety percent of patients complained of tingling ( P = 0.000) before surgery and 18% after surgery, whereas 100% complained of numbness before surgery and 41% ( P = 0.000) after surgery. One hundred percent of patients had no measurable surface sensitivity before surgery (measured with the Semes-Weinstein monofilament), whereas 3 months after surgery, only 24% of patients still had no measurable surface sensitivity ( P = 0.000). A positive Hoffmann-Tinel sign was recorded in 85% of patients before surgery and only in 11% 3 months after surgery ( P = 0.000). In the case of patients with idiopathic polyneuropathy, a reduction in pain was evident 3 months after surgery, from a preoperative level of NRS 3.9 (minimum, 0; maximum, 9) to 2.2 (minimum, 0; maximum, 9; P = 0.058). Seventy-seven percent of patients complained of tingling before surgery and 42% after surgery ( P = 0.111), whereas 92% complained of numbness before surgery and 50% after surgery ( P = 0.030). Seventy-seven percent of patients had no measurable surface sensitivity before surgery (measured with the Semes-Weinstein monofilament), whereas 3 months after surgery, only 33% of patients still had no measurable surface sensitivity ( P = 0.047). A positive Hoffmann-Tinel sign was recorded in 62% of patients before surgery and only in 17% 3 months after surgery ( P = 0.041). CONCLUSIONS: Not only patients with diabetic polyneuropathy but also those with idiopathic polyneuropathy benefit from Dellon nerve decompression surgery in the lower extremities.

Sympathetic skin response for early detection of type 2 diabetic peripheral neuropathy and nephropathy.

BACKGROUND: Diabetic peripheral neuropathy (DPN) and diabetic nephropathy (DN) are common complications of type 2 diabetes mellitus (T2DM). Although nerve conduction studies (NCS) and sympathetic skin response (SSR) can detect DPN, the more sensitive method for early diagnosis remains unclear. Furthermore, whether DPN can be used as a predictor for diabetic nephropathy needs clarification. METHODS: We evaluated nerve conduction studies, sympathetic skin response, and the diabetic nephropathy indicator microalbuminuria (MAU) in 192 patients with type 2 diabetes mellitus and 50 healthy controls. RESULTS: Patients with type 2 diabetes mellitus showed a lower sensory nerve conduction velocity (SCV), sensory active nerve potential (SNAP), motor nerve conduction velocity (MCV), and compound motor action potential (CMAP) than the controls on NCS. Abnormal rates for nerve conduction studies and sympathetic skin response were 75.0% and 83.3%, respectively, in patients with type 2 diabetes mellitus. Interestingly, 54.2% of patients with normal nerve conduction studies had an abnormal sympathetic skin response. Moreover, we found a positive correlation between sympathetic skin response and microalbuminuria for the first time. The abnormal rate of microalbuminuria was 53.8%, lower than that of abnormal nerve conduction studies or sympathetic skin response patients. CONCLUSION: Sympathetic skin response is a more sensitive method than nerve conduction studies for the early diagnosis of diabetic peripheral neuropathy. Abnormal sympathetic skin response might serve as an indicator for early diabetic nephropathy. Additionally, diabetic peripheral neuropathy may occur earlier than diabetic nephropathy in the development of type 2 diabetes mellitus.

4. Painful diabetic polyneuropathy.

INTRODUCTION: Pain as a symptom of diabetic polyneuropathy (DPN) significantly lowers quality of life, increases mortality and is the main reason for patients with diabetes to seek medical attention. The number of people suffering from painful diabetic polyneuropathy (PDPN) has increased significantly over the past decades. METHODS: The literature on the diagnosis and treatment of diabetic polyneuropathy was retrieved and summarized. RESULTS: The etiology of PDPN is complex, with primary damage to peripheral nociceptors and altered spinal and supra-spinal modulation. To achieve better patient outcomes, the mode of diagnosis and treatment of PDPN evolves toward more precise pain-phenotyping and genotyping based on patient-specific characteristics, new diagnostic tools, and prior response to pharmacological treatments. According to the Toronto Diabetic Neuropathy Expert Group, a presumptive diagnosis of "probable PDPN" is sufficient to initiate treatment. Proper control of plasma glucose levels, and prevention of risk factors are essential in the treatment of PDPN. Mechanism-based pharmacological treatment should be initiated as early as possible. If symptomatic pharmacologic treatment fails, spinal cord stimulation (SCS) should be considered. In isolated cases, where symptomatic pharmacologic treatment and SCS are unsuccessful or cannot be used, sympathetic lumbar chain neurolysis and/or radiofrequency ablation (SLCN/SLCRF), dorsal root ganglion stimulation (DRGs) or posterior tibial nerve stimulation (PTNS) may be considered. However, it is recommended that these treatments be applied only in a study setting in a center of expertise. CONCLUSIONS: The diagnosis of PDPN evolves toward pheno-and genotyping and treatment should be mechanism-based.

Temporal Trends in Distal Symmetric Polyneuropathy in Type 2 Diabetes: The Fremantle Diabetes Study.

CONTEXT: Macrovascular outcomes in type 2 diabetes have improved over recent decades. There are scant equivalent distal symmetric polyneuropathy (DSPN) data. OBJECTIVE: This work aimed to characterize temporal changes in DSPN prevalence and incidence rates (IRs) in community-based Australians. METHODS: An observational study was conducted among an urban population. Participants included individuals with type 2 diabetes from the Fremantle Diabetes Study phases I (FDS1; n = 1296 recruited 1993-1996) and II (FDS2; n = 1509 recruited 2008-2011). Main outcome measures included Michigan Neuropathy Screening Instrument (MNSI) clinical grading. RESULTS: DSPN prevalence by 8-point MNSI was 30.8% (FDS1) and 58.9% (FDS2; P < .001), and by 6-point (excluding foot appearance) and 2-point (biothesiometry alone) MNSI was 37.5% and 35.7% (P = .336), and 33.8% and 38.7% (P = .011), respectively. Given between-phase changes in appearance assessment, 8-point MNSI data were not analyzed further. In multivariable analysis, FDS2 vs FDS1 participation was associated with 6-point (odds ratio (95% CI) 0.68 (0.56-0.83); P < .001) but not 2-point (0.90 (0.74-1.11); P = .326) MNSI DSPN prevalence. Four-year DSPN IRs (95% CI) for 6-point MNSI were 13.6 (12.0-15.4) and 17.6 (15.9-19.4)/100 person-years in FDS1 and FDS2, respectively (IR ratio [IRR] 1.31 [1.12-1.55]; P < .001), and for 2-point MNSI were 13.9 (12.3-15.8) and 7.4 (16.3-8.6/100 person-years; IRR 0.53 [0.43-0.64]; P < .001). FDS2 vs FDS1 independently predicted incident DSPN for 6-point (hazard ratio [95% CI] 1.25 [1.06-1.48]; P = .009) and 2-point (0.42 [0.33-0.55]; P < .001) MNSI. CONCLUSION: DSPN prevalence was lower or equivalent in FDS2 vs FDS1, and its incidence was greater or lower, in multivariable models depending on the MNSI features used.

The co-existence of peripheral and vestibular neuropathy in diabetes: a cross-sectional study.

PURPOSE: Diabetic neuropathy can lead to decreased peripheral sensation and motor neuron dysfunction associated with impaired postural control and risk of falling. However, the relationship between decreased peripheral sensation and impaired vestibular function in diabetes mellitus is poorly investigated. Therefore, the aim of this study was to investigate the relationship between peripheral and autonomic measurements of diabetic neuropathy and measurements of vestibular function. METHODS: A total of 114 participants with type 1 diabetes (n = 52), type 2 diabetes (n = 51) and controls (n = 11) were included. Vestibular function was evaluated by video head impulse testing. Peripheral neuropathy was assessed by quantitative sensory testing and nerve conduction. Autonomic neuropathy using the COMPASS 31 questionnaire. Data were analyzed according to data type and distribution. RESULTS: Measurements of vestibular function did not differ between participants with type 1 diabetes, type 2 diabetes or controls (all p-values above 0.05). Subgrouping of participants according to the involvement of large-, small- or autonomic nerves did not change this outcome. Correlation analyses showed a significant difference between COMPASS 31 and right lateral gain value (ρ = 0.23, p = 0.02,), while no other significant correlations were found. CONCLUSION: Diabetic neuropathy does not appear to impair vestibular function in diabetes, by means of the VOR. CLINICAL TRIALS: NCT05389566, May 25th, 2022.

The Mas-related G protein-coupled receptor d (Mrgprd) mediates pain hypersensitivity in painful diabetic neuropathy.

ABSTRACT: Painful diabetic neuropathy (PDN) is one of the most common and intractable complications of diabetes. Painful diabetic neuropathy is characterized by neuropathic pain accompanied by dorsal root ganglion (DRG) nociceptor hyperexcitability, axonal degeneration, and changes in cutaneous innervation. However, the complete molecular profile underlying the hyperexcitable cellular phenotype of DRG nociceptors in PDN has not been elucidated. This gap in our knowledge is a critical barrier to developing effective, mechanism-based, and disease-modifying therapeutic approaches that are urgently needed to relieve the symptoms of PDN. Using single-cell RNA sequencing of DRGs, we demonstrated an increased expression of the Mas-related G protein-coupled receptor d (Mrgprd) in a subpopulation of DRG neurons in the well-established high-fat diet (HFD) mouse model of PDN. Importantly, limiting Mrgprd signaling reversed mechanical allodynia in the HFD mouse model of PDN. Furthermore, in vivo calcium imaging allowed us to demonstrate that activation of Mrgprd-positive cutaneous afferents that persist in diabetic mice skin resulted in an increased intracellular calcium influx into DRG nociceptors that we assess in vivo as a readout of nociceptors hyperexcitability. Taken together, our data highlight a key role of Mrgprd-mediated DRG neuron excitability in the generation and maintenance of neuropathic pain in a mouse model of PDN. Hence, we propose Mrgprd as a promising and accessible target for developing effective therapeutics currently unavailable for treating neuropathic pain in PDN.

Balance and gait in individuals with diabetic peripheral neuropathy.

BACKGROUND: Diabetic Peripheral Neuropathy (DPN) causes various physical problems such as the increased risk of falling, loss of balance and coordination while standing or walking, susceptibility to injuries due to sensory loss. AIMS: The aim of the study was to evaluate and compare the effects of neuropathic pain (NP) in individuals with DPN on balance and gait. METHODS: This prospective controlled study was conducted on 42 adults aged between 40-65 years. The participants were divided into three groups; individuals with DPN and NP (DPN+NP/n = 14), individuals with DPN without NP (DPN-NP/n = 14), and the control group (n = 14), respectively. The Force Plate system and Core Balance System measured static and dynamic postural balance and stability limits. Gait and dynamic plantar pressure distribution analyses were performed with a computerized gait evaluation system. RESULTS: The score of LANSS, and VAS during gait were higher in DPN+NP group than in DPN-NP (p < 0.05). No significant difference was observed between the groups in balance parameters (p > 0.05). The right-left heel maximum forces were lower in both groups with DPN compared to the control group (p < 0.05). In terms of spatiotemporal parameters of the gait, there was a difference between the groups only in step width and left single support line parameters (p < 0.05). CONCLUSIONS: The results of this study indicate that the individuals with DPN have an increased step width, their left single support line was shortened, and the maximum force on the heel decreased. The NP did not cause any change in balance and gait parameters.

Neuropathic Pain in Aged People: An Unresolved Issue Open to Novel Drug Approaches, Focusing on Painful Diabetic Neuropathy.

A majority of older patients suffer from neuropathic pain (NP) that significantly alters their daily activities and imposes a significant burden on health care. Multiple comorbidities and the risk of polypharmacy in the elderly make it challenging to determine the appropriate drug, dosage, and maintenance of therapy. Age-dependent processes play a contributing role in neuropathy given that diabetic neuropathy (DN) is the most common form of neuropathy. This narrative review is mainly focused on the drug treatment approach for neuropathy-associated pain in aged people including both drugs and dietary supplements, considering the latter as add-on mechanism-based treatments to increase the effectiveness of usual treatments by implementing their activity or activating other analgesic pathways. On one hand, the limited clinical studies assessing the effectiveness and the adverse effects of existing pain management options in this age segment of the population (> 65), on the other hand, the expanding global demographics of the elderly contribute to building up an unresolved pain management problem that needs the attention of healthcare providers, researchers, and health authorities as well as the expansion of the current therapeutic options.