Spectrum of Diabetic Neuropathy: New Insights in Diagnosis and Treatment.

Diabetic neuropathy is a highly prevalent complication of diabetes. It consists of a broad range of neuropathic conditions, such as distal symmetric polyneuropathy and various forms of autonomic neuropathies involving the cardiovascular, gastrointestinal, and urogenital systems. Prevention or diagnosis in early stages of disease is crucial to prevent symptomatic onset and progression, particularly in the absence of current disease-modifying therapies. In this review, we describe the four main types of diabetic neuropathy. We review current understanding with respect to diagnosis and treatment while highlighting knowledge gaps and future directions.

Cardiovascular autonomic neuropathy in diabetes: an update with a focus on management.

Cardiovascular autonomic neuropathy (CAN) is an under-recognised yet highly prevalent microvascular complication of diabetes. CAN affects approximately 20% of people with diabetes, with recent studies highlighting the presence of CAN in prediabetes (impaired glucose tolerance and/or impaired fasting glucose), indicating early involvement of the autonomic nervous system. Understanding of the pathophysiology of CAN continues to evolve, with emerging evidence supporting a potential link between lipid metabolites, mitochondrial dysfunction and genetics. Recent advancements, such as streamlining CAN detection through wearable devices and monitoring of heart rate variability, present simplified and cost-effective approaches for early CAN detection. Further research on the optimal use of the extensive data provided by such devices is required. Despite the lack of specific pharmacological interventions targeting the underlying pathophysiology of autonomic neuropathy, several studies have suggested a favourable impact of newer glucose-lowering agents, such as sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide-1 receptor agonists, where there is a wealth of clinical trial data on the prevention of cardiovascular events. This review delves into recent developments in the area of CAN, with emphasis on practical guidance to recognise and manage this underdiagnosed condition, which significantly increases the risk of cardiovascular events and mortality in diabetes.

Transcutaneous vagal nerve stimulation for treating gastrointestinal symptoms in individuals with diabetes: a randomised, double-blind, sham-controlled, multicentre trial.

AIMS/HYPOTHESIS: Diabetic gastroenteropathy frequently causes debilitating gastrointestinal symptoms. Previous uncontrolled studies have shown that transcutaneous vagal nerve stimulation (tVNS) may improve gastrointestinal symptoms. To investigate the effect of cervical tVNS in individuals with diabetes suffering from autonomic neuropathy and gastrointestinal symptoms, we conducted a randomised, sham-controlled, double-blind (participants and investigators were blinded to the allocated treatment) study. METHODS: This study included adults (aged 20-86) with type 1 or 2 diabetes, gastrointestinal symptoms and autonomic neuropathy recruited from three Steno Diabetes Centres in Denmark. Participants were randomly allocated 1:1 to receive active or sham stimulation. Active cervical tVNS or sham stimulation was self-administered over two successive study periods: 1 week of four daily stimulations and 8 weeks of two daily stimulations. The primary outcome measures were gastrointestinal symptom changes as measured using the gastroparesis cardinal symptom index (GCSI) and the gastrointestinal symptom rating scale (GSRS). Secondary outcomes included gastrointestinal transit times and cardiovascular autonomic function. RESULTS: Sixty-eight participants were randomised to the active group, while 77 were randomised to the sham group. Sixty-three in the active and 68 in the sham group remained for analysis in study period 1, while 62 in each group were analysed in study period 2. In study period 1, active and sham tVNS resulted in similar symptom reductions (GCSI: -0.26 ± 0.64 vs -0.17 ± 0.62, p=0.44; GSRS: -0.35 ± 0.62 vs -0.32 ± 0.59, p=0.77; mean ± SD). In study period 2, active stimulation also caused a mean symptom decrease that was comparable to that observed after sham stimulation (GCSI: -0.47 ± 0.78 vs -0.33 ± 0.75, p=0.34; GSRS: -0.46 ± 0.90 vs -0.35 ± 0.79, p=0.50). Gastric emptying time was increased in the active group compared with sham (23 min vs -19 min, p=0.04). Segmental intestinal transit times and cardiovascular autonomic measurements did not differ between treatment groups (all p>0.05). The tVNS was well-tolerated. CONCLUSIONS/INTERPRETATION: Cervical tVNS, compared with sham stimulation, does not improve gastrointestinal symptoms among individuals with diabetes and autonomic neuropathy. TRIAL REGISTRATION: ClinicalTrials.gov NCT04143269 FUNDING: The study was funded by the Novo Nordisk Foundation (grant number NNF180C0052045).

Artificial intelligence-based classification of cardiac autonomic neuropathy from retinal fundus images in patients with diabetes: The Silesia Diabetes Heart Study.

BACKGROUND: Cardiac autonomic neuropathy (CAN) in diabetes mellitus (DM) is independently associated with cardiovascular (CV) events and CV death. Diagnosis of this complication of DM is time-consuming and not routinely performed in the clinical practice, in contrast to fundus retinal imaging which is accessible and routinely performed. Whether artificial intelligence (AI) utilizing retinal images collected through diabetic eye screening can provide an efficient diagnostic method for CAN is unknown. METHODS: This was a single center, observational study in a cohort of patients with DM as a part of the Cardiovascular Disease in Patients with Diabetes: The Silesia Diabetes-Heart Project (NCT05626413). To diagnose CAN, we used standard CV autonomic reflex tests. In this analysis we implemented AI-based deep learning techniques with non-mydriatic 5-field color fundus imaging to identify patients with CAN. Two experiments have been developed utilizing Multiple Instance Learning and primarily ResNet 18 as the backbone network. Models underwent training and validation prior to testing on an unseen image set. RESULTS: In an analysis of 2275 retinal images from 229 patients, the ResNet 18 backbone model demonstrated robust diagnostic capabilities in the binary classification of CAN, correctly identifying 93% of CAN cases and 89% of non-CAN cases within the test set. The model achieved an area under the receiver operating characteristic curve (AUCROC) of 0.87 (95% CI 0.74-0.97). For distinguishing between definite or severe stages of CAN (dsCAN), the ResNet 18 model accurately classified 78% of dsCAN cases and 93% of cases without dsCAN, with an AUCROC of 0.94 (95% CI 0.86-1.00). An alternate backbone model, ResWide 50, showed enhanced sensitivity at 89% for dsCAN, but with a marginally lower AUCROC of 0.91 (95% CI 0.73-1.00). CONCLUSIONS: AI-based algorithms utilising retinal images can differentiate with high accuracy patients with CAN. AI analysis of fundus images to detect CAN may be implemented in routine clinical practice to identify patients at the highest CV risk. TRIAL REGISTRATION: This is a part of the Silesia Diabetes-Heart Project (Clinical-Trials.gov Identifier: NCT05626413).

Prevalence and prognostic significance of cardiac autonomic neuropathy in community-based people with type 2 diabetes: the Fremantle Diabetes Study Phase II.

BACKGROUND: There is a paucity of contemporary data on the prevalence and prognostic significance of cardiac autonomic neuropathy (CAN) from community-based cohorts with type 2 diabetes assessed using gold standard methods. The aim of this study was to assess these aspects of CAN in the longitudinal observational Fremantle Diabetes Study Phase II (FDS2). METHODS: FDS2 participants were screened at baseline using standardised cardiovascular reflex tests (CARTs) of heart rate variation during deep breathing, Valsalva manoeuvre and standing. CAN (no/possible/definite) was assessed from the number of abnormal CARTs. Multinomial regression identified independent associates of CAN status. Cox proportional hazards modelling determined independent baseline predictors of incident heart failure (HF) and ischaemic heart disease (IHD), and all-cause mortality. RESULTS: Of 1254 participants assessed for CAN, 86 (6.9%) were outside CART age reference ranges and valid CART data were unavailable for 338 (27.0%). Of the remaining 830 (mean age 62.3 years, 55.3% males, median diabetes duration 7.3 years), 51.0%, 33.7% and 15.3% had no, possible or definite CAN, respectively. Independent associates of definite CAN (longer diabetes duration, higher body mass index and resting pulse rate, antidepressant and antihypertensive therapies, albuminuria, distal sensory polyneuropathy, prior HF) were consistent with those reported previously. In Kaplan-Meier analysis, definite CAN was associated with a lower likelihood of incident IHD and HF versus no/possible CAN (P < 0.001) and there was a graded increase in all-cause mortality risk from no CAN to possible and definite CAN (P < 0.001). When CAN category was added to the most parsimonious models, it was not a significant independent predictor of IHD (P ≥ 0.851) or HF (P ≥ 0.342). Possible CAN (hazard ratio (95% CI) 1.47 (1.01, 2.14), P = 0.046) and definite CAN (2.42 (1.60, 3.67), P < 0.001) increased the risk of all-cause mortality versus no CAN. CONCLUSIONS: Routine screening for CAN in type 2 diabetes has limited clinical but some prognostic value.

Diabetic autonomic neuropathy does not impede improvement in hypoglycaemia awareness in adults: Sub-study results from the HypoCOMPaSS trial.

AIMS: Impaired awareness of hypoglycaemia (IAH) increases the risk of severe hypoglycaemia in people with type 1 diabetes mellitus (T1DM). IAH can be reversed through meticulous avoidance of hypoglycaemia. Diabetic autonomic neuropathy (DAN) has been proposed as an underlying mechanism contributing to IAH; however, data are inconsistent. The aim of this study was to examine the effects of cardiac autonomic neuropathy (CAN) on IAH reversibility inT1DM. METHODS: Participants with T1DM and IAH (Gold score ≥4) recruited to the HypoCOMPaSS (24-week 2 × 2 factorial randomised controlled) trial were included. All underwent screening for cardiac autonomic function testing at baseline and received comparable education and support aimed at avoiding hypoglycaemia and improving hypoglycaemia awareness. Definite CAN was defined as the presence of ≥2 abnormal cardiac reflex tests. Participants were grouped according to their CAN status, and changes in Gold score were compared. RESULTS: Eighty-three participants (52 women [62.7%]) were included with mean age (SD) of 48 (12) years and mean HbA1c of 66 (13) mmol/mol (8.2 [3.3] %). The mean duration of T1DM was 29 (13) years. The prevalence of CAN was low with 5/83 (6%) participants having definite autonomic neuropathy with 11 (13%) classified with possible/early neuropathy. All participants, regardless of the autonomic function status, showed a mean improvement in Gold score of ≥1 (mean improvement -1.2 [95% CI -0.8, -1.6]; p < 0.001). CONCLUSIONS: IAH can be improved in people with T1DM, and a long duration of disease, with and without cardiac autonomic dysfunction. These data suggest that CAN is not a prime driver for modulating IAH reversibility.

TECPR2-related hereditary sensory and autonomic neuropathy in two siblings from Palestine.

Due to the majority of currently available genome data deriving from individuals of European ancestry, the clinical interpretation of genomic variants in individuals from diverse ethnic backgrounds remains a major diagnostic challenge. Here, we investigated the genetic cause of a complex neurodevelopmental phenotype in two Palestinian siblings. Whole exome sequencing identified a homozygous missense TECPR2 variant (Chr14(GRCh38):g.102425085G>A; NM_014844.5:c.745G>A, p.(Gly249Arg)) absent in gnomAD, segregating appropriately with the inheritance pattern in the family. Variant assessment with in silico pathogenicity prediction and protein modeling tools alongside population database frequencies led to classification as a variant of uncertain significance. As pathogenic TECPR2 variants are associated with hereditary sensory and autonomic neuropathy with intellectual disability, we reviewed previously published candidate TECPR2 missense variants to clarify clinical outcomes and variant classification using current approved guidelines, classifying a number of published variants as of uncertain significance. This work highlights genomic healthcare inequalities and the challenges in interpreting rare genetic variants in populations underrepresented in genomic databases. It also improves understanding of the clinical and genetic spectrum of TECPR2-related neuropathy and contributes to addressing genomic data disparity and inequalities of the genomic architecture in Palestinian populations.

Artificial intelligence-enhanced electrocardiogram analysis for identifying cardiac autonomic neuropathy in patients with diabetes.

AIM: To develop and employ machine learning (ML) algorithms to analyse electrocardiograms (ECGs) for the diagnosis of cardiac autonomic neuropathy (CAN). MATERIALS AND METHODS: We used motif and discord extraction techniques, alongside long short-term memory networks, to analyse 12-lead, 10-s ECG tracings to detect CAN in patients with diabetes. The performance of these methods with the support vector machine classification model was evaluated using 10-fold cross validation with the following metrics: accuracy, precision, recall, F1 score, and area under the receiver-operating characteristic curve (AUC). RESULTS: Among 205 patients (mean age 54 ± 17 years, 54% female), 100 were diagnosed with CAN, including 38 with definite or severe CAN (dsCAN) and 62 with early CAN (eCAN). The best model performance for dsCAN classification was achieved using both motifs and discords, with an accuracy of 0.92, an F1 score of 0.92, a recall at 0.94, a precision of 0.91, and an excellent AUC of 0.93 (95% confidence interval [CI] 0.91-0.94). For the detection of any stage of CAN, the approach combining motifs and discords yielded the best results, with an accuracy of 0.65, F1 score of 0.68, a recall of 0.75, a precision of 0.68, and an AUC of 0.68 (95% CI 0.54-0.81). CONCLUSION: Our study highlights the potential of using ML techniques, particularly motifs and discords, to effectively detect dsCAN in patients with diabetes. This approach could be applied in large-scale screening of CAN, particularly to identify definite/severe CAN where cardiovascular risk factor modification may be initiated.

Genetic markers of cardiac autonomic neuropathy in the Kazakh population.

BACKGROUND: Cardiac autonomic neuropathy (CAN) is a complication of diabetes mellitus (DM) that increases the risk of morbidity and mortality by disrupting cardiac innervation. Recent evidence suggests that CAN may manifest even before the onset of DM, with prediabetes and metabolic syndrome potentially serving as precursors. This study aims to identify genetic markers associated with CAN development in the Kazakh population by investigating the SNPs of specific genes. MATERIALS AND METHODS: A case-control study involved 82 patients with CAN (cases) and 100 patients without CAN (controls). A total of 182 individuals of Kazakh nationality were enrolled from a hospital affiliated with the RSE "Medical Center Hospital of the President's Affairs Administration of the Republic of Kazakhstan". 7 SNPs of genes FTO, PPARG, SNCA, XRCC1, FLACC1/CASP8 were studied. Statistical analysis was performed using Chi-square methods, calculation of odds ratios (OR) with 95% confidence intervals (CI), and logistic regression in SPSS 26.0. RESULTS: Among the SNCA gene polymorphisms, rs2737029 was significantly associated with CAN, almost doubling the risk of CAN (OR 2.03(1.09-3.77), p = 0.03). However, no statistically significant association with CAN was detected with the rs2736990 of the SNCA gene (OR 1.00 CI (0.63-1.59), p = 0.99). rs12149832 of the FTO gene increased the risk of CAN threefold (OR 3.22(1.04-9.95), p = 0.04), while rs1801282 of the PPARG gene and rs13016963 of the FLACC1 gene increased the risk twofold (OR 2.56(1.19-5.49), p = 0.02) and (OR 2.34(1.00-5.46), p = 0.05) respectively. rs1108775 and rs1799782 of the XRCC1 gene were associated with reduced chances of developing CAN both before and after adjustment (OR 0.24, CI (0.09-0.68), p = 0.007, and OR 0.43, CI (0.22-0.84), p = 0.02, respectively). CONCLUSION: The study suggests that rs2737029 (SNCA gene), rs12149832 (FTO gene), rs1801282 (PPARG gene), and rs13016963 (FLACC1 gene) may be predisposing factors for CAN development. Additionally, SNPs rs1108775 and rs1799782 (XRCC1 gene) may confer resistance to CAN. Only one polymorphism rs2736990 of the SNCA gene was not associated with CAN.

Cardiac Autonomic Neuropathy in Graves' Disease: Smoking and Age as Predictive Factors.

OBJECTIVES: Hypermetabolic state in Graves' disease (GD) has a great impact on heart homeostasis, acting directly on the heart muscle and modulating the autonomic nervous system. To characterize cardiac autonomic neuropathy (CAN) as a possible complication in patients with GD. METHODS: We evaluated euthyroid GD patients and a control group of healthy euthyroid people. CAN was assessed using autonomic tests of cardiovascular reflex and heart rate variability: respiratory, Valsalva, orthostatic and orthostatic hypotension tests, high frequency, low frequency, and very low-frequency bands. Transthoracic echocardiography was performed in GD patients. RESULTS: Sixty GD patients and 50 people in control group were assessed. CAN was diagnosed in 20% of GD and 14% in the control group. Among GD, 13.3% presented incipient, and 6.7% established CAN, while in the control group, it was verified incipient in 8% and established in 6% (P = .7479). All GD patients with CAN presented an alteration in the deep breathing test. Age and smoking were evidenced as factors associated with the presence of CAN, while higher TRAb values at diagnosis decreased the chance of CAN. CONCLUSIONS: The prevalence of CAN in euthyroid GD patients was 20%. Changes in the cardiac autonomic nervous system were identified, pointing to the importance of evaluating this complication in these patients. Smoking was a predictive factor for CAN, increasing its relationship with conditions that aggravate GD.

Autonomic neuropathy in dialysis patients - investigations with a new symptom score (COMPASS 31).

BACKGROUND: Symptoms of autonomic neuropathy (AN) are common in patients with diabetes and advanced renal disease. As yet different domains of autonomic neuropathy cannot be detected by a singular laboratory or invasive test. COMPASS 31, a new self-assessment test, has shown reliable results not only in cardiac autonomic neuropathy but also in different sub-domains when judging manifestation of AN by scores. METHODS: One hundred eighty-three patients with or without diabetes were enrolled, one hundred nineteen of them were treated with permanent dialysis therapy (HD), sixty-four patients served as controls (eGFR > 60 ml/min.) Using COMPASS 31 different symptoms of AN were assessed (orthostatic intolerance, vasomotor, secretomotor, gastrointestinal, bladder, pupillomotor changes) and transferred into AN-scores. RESULTS: AN was more pronounced in dialysis patients compared with controls (AN-score 27,5 vs. 10,0; p < 0,01). These differences were present also in every sub-domain of AN (orthostatic intolerance, vasomotor, secretomotor, gastrointestinal, bladder, pupillomotor changes; p < 0,05 for all sub-domains). In diabetic patients there was a strong correlation between symptoms of AN and diabetes duration (correlation coefficient r = 0,45, p < 0,001). Current glycemic control (HbA1c), body mass index (BMI), sex, and height had no influence on AN when comparing dialysis patients and controls. C-reactive protein (CRP) showed a positive linear correlation with AN-scores (correlation coefficient r = 0,21; p < 0,05). CONCLUSION: Symptoms of AN are more pronounced in dialysis patients not only in total but also in all different domains of neuropathic changes. Longlasting diabetic disease promotes development of AN, as duration of diabetes was positively correlated with AN. Future longitudinal studies might help to identify the high cardiovascular and mortality risk in dialysis patients by the easy-to-use COMPASS 31 without need of invasive and time-spending methods for diagnosing AN.

Neurofilament Light Chains in Systemic Amyloidosis: A Systematic Review.

Peripheral and autonomic neuropathy are common disease manifestations in systemic amyloidosis. The neurofilament light chain (NfL), a neuron-specific biomarker, is released into the blood and cerebrospinal fluid after neuronal damage. There is a need for an early and sensitive blood biomarker for polyneuropathy, and this systematic review provides an overview on the value of NfL in the early detection of neuropathy, central nervous system involvement, the monitoring of neuropathy progression, and treatment effects in systemic amyloidosis. A literature search in PubMed, Embase, and Web of Science was performed on 14 February 2024 for studies investigating NfL levels in patients with systemic amyloidosis and transthyretin gene-variant (TTRv) carriers. Only studies containing original data were included. Included were thirteen full-text articles and five abstracts describing 1604 participants: 298 controls and 1306 TTRv carriers or patients with or without polyneuropathy. Patients with polyneuropathy demonstrated higher NfL levels compared to healthy controls and asymptomatic carriers. Disease onset was marked by rising NfL levels. Following the initiation of transthyretin gene-silencer treatment, NfL levels decreased and remained stable over an extended period. NfL is not an outcome biomarker, but an early and sensitive disease-process biomarker for neuropathy in systemic amyloidosis. Therefore, NfL has the potential to be used for the early detection of neuropathy, monitoring treatment effects, and monitoring disease progression in patients with systemic amyloidosis.

Collagen turnover is associated with cardiovascular autonomic and peripheral neuropathy in type 1 diabetes: novel pathophysiological mechanism?

BACKGROUND: Diabetic cardiovascular autonomic neuropathy (CAN) and distal symmetrical polyneuropathy (DSPN) are severe diabetic complications. Collagen type VI (COL6) and III (COL3) have been associated with nerve function. We investigated if markers of COL6 formation (PRO-C6) and COL3 degradation (C3M) were associated with neuropathy in people with type 1 diabetes (T1D). METHODS: In a cross-sectional study including 300 people with T1D, serum and urine PRO-C6 and C3M were obtained. CAN was assessed by cardiovascular reflex tests: heart rate response to deep breathing (E/I ratio), to standing (30/15 ratio) and to the Valsalva maneuver (VM). Two or three pathological CARTs constituted CAN. DSPN was assessed by biothesiometry. Symmetrical vibration sensation threshold above 25 V constituted DSPN. RESULTS: Participants were (mean (SD)) 55.7 (9.3) years, 51% were males, diabetes duration was 40.0 (8.9) years, HbA1c was 63 (11 mmol/mol, (median (IQR)) serum PRO-C6 was 7.8 (6.2;11.0) ng/ml and C3M 8.3 (7.1;10.0) ng/ml. CAN and DSPN were diagnosed in 34% and 43% of participants, respectively. In models adjusted for relevant confounders a doubling of serum PRO-C6, was significantly associated with odds ratio > 2 for CAN and > 1 for DSPN, respectively. Significance was retained after additional adjustments for eGFR only for CAN. Higher serum C3M was associated with presence of CAN, but not after adjustment for eGFR. C3M was not associated with DSPN. Urine PRO-C6 analyses indicated similar associations. CONCLUSIONS: Results show previously undescribed associations between markers of collagen turnover and risk of CAN and to a lesser degree DSPN in T1D.

Neuropathy in prediabetes.

Diabetic neuropathies are the most frequent complications of diabetes, contributing to high morbidity, excess mortality, reduced quality of life, and increased healthcare costs. Prediabetes is characterised by glucose levels within an intermediate range above normoglycaemia yet below the diagnostic threshold for diabetes. In 2021, 10.6% and 6.2% of adults worldwide were estimated to have impaired glucose tolerance and impaired fasting glucose, respectively, the majority of whom are unaware of having prediabetes. Evidence has accumulated suggesting that prediabetes is a predictor of cardiovascular disease (CVD) and increased mortality. The past 2 decades have witnessed an extensive debate, particularly among diabetologists and neurologists, as to whether prediabetes is associated with peripheral neuropathy. In this review, we elaborate on the current evidence, particularly from population-based studies supporting an increased risk of distal sensorimotor polyneuropathy (DSPN) and cardiovascular autonomic neuropathy (CAN) in people with prediabetes. Moreover, we discuss whether lifestyle interventions showing efficacy in preventing or delaying the transition from prediabetes to diabetes in persons with prediabetes may also exert favourable effects on the development and progression of DSPN and CAN. This review should help in raising the awareness of and translating the current knowledge on neuropathies in people with prediabetes into clinical practice and public health. The current recommendation that adults who are overweight or obese should be screened for prediabetes and referred to or offered preventive interventions should ultimately culminate in preventing not only CVD but also prediabetic neuropathy.

In vivo molecular imaging of cardiac angiogenesis in persons with and without type 2 diabetes: A cross-sectional 68 Ga-RGD-PET study.

AIMS: To assess cardiac angiogenesis in type 2 diabetes by positron emission tomography (PET) tracer [68 Ga]Ga-NODAGA-E[(cRGDyK)]2 (68 Ga-RGD) imaging. METHODS: Cross-sectional study including 20 persons with type 2 diabetes and 10 non-diabetic controls (CONs). Primary prespecified outcome was difference in cardiac angiogenesis (cardiac 68 Ga-RGD mean target-to-background ratio [TBRmean ]) between type 2 diabetes and CONs. Secondary outcome was to investigate associations between cardiac angiogenesis and kidney function and other risk factors. RESULTS: Participants with type 2 diabetes had a mean ± SD age of 61 ± 9 years, 30% were women, median (IQR) diabetes duration of 11 (6-19) years and 3 (15%) had a history of cardiovascular disease. The CONs had comparable age and sex distribution to the participants with type 2 diabetes, and none had a history of coronary artery disease. Myocardial flow reserve was lower in type 2 diabetes (2.7 ± 0.6) compared with CONs (3.4 ± 1.2) ( p  = 0.03) and coronary artery calcium score was higher (562 [142-905] vs. 1 [0-150] p  = 0.04). Cardiac 68 Ga-RGD TBRmean was similar in participants with type 2 diabetes (0.89 ± 0.09) and CONs (0.89 ± 0.10) ( p  = 0.92). Cardiac 68 Ga-RGD TBRmean was not associated with estimated glomerular filtration rate, urine albumin creatinine ratio, cardiovascular disease, coronary artery calcium score or baroreflex sensitivity, neither in pooled analyses nor in type 2 diabetes. CONCLUSIONS: Cardiac angiogenesis, evaluated with 68 Ga-RGD PET, was similar in type 2 diabetes and CONs. Cardiac angiogenesis was not associated with kidney function or other risk markers in pooled analyses or in analyses restricted to type 2 diabetes.

Detecting and treating the protean manifestations of diabetic autonomic neuropathy.

The manifestations of diabetic autonomic neuropathy (DAN) are protean and clinically involve multiple systems, including the cardiovascular system, the gastrointestinal system, the genitourinary system as well as the sweat glands (sudomotor dysfunction) and the gallbladder. In addition, cardiac autonomic neuropathy (CAN) is associated with a correctible inability to appreciate and correct hypoglycaemia. While not a clinical problem, pupillary involvement should be the clue and the catalyst to investigate for other manifestations of DAN. This review outlines a practical approach to detecting and investigating the manifestations of DAN. Of particular importance is early detection of cardiovascular involvement where prompt therapy through glycaemic control can decrease the severity of CAN and decelerate the frequency and severity of retinopathy and nephropathy in addition to decreasing cardiovascular events and mortality. CAN also plays a role in accelerating other diabetic complications such as acute ischaemic stroke, heart failure, medial artery calcinosis, foot ulcers, peripheral artery disease and Charcot joints. Many therapies of DAN are available, which should not only decrease morbidity and mortality from DAN, but also improve the patient's quality of life. However, the therapies available are largely symptomatic.

A novel HSPB1S139F mouse model of Charcot-Marie-Tooth Disease.

Charcot-Marie-Tooth Disease (CMT) is a commonly inherited peripheral polyneuropathy. Clinical manifestations for this disease include symmetrical distal polyneuropathy, altered deep tendon reflexes, distal sensory loss, foot deformities, and gait abnormalities. Genetic mutations in heat shock proteins have been linked to CMT2. Specifically, mutations in the heat shock protein B1 (HSPB1) gene encoding for heat shock protein 27 (Hsp27) have been linked to CMT2F and distal hereditary motor and sensory neuropathy type 2B (dHMSN2B) subtype. The goal of the study was to examine the role of an endogenous mutation in HSPB1 in vivo and to define the effects of this mutation on motor function and pathology in a novel animal model. As sphingolipids have been implicated in hereditary and sensory neuropathies, we examined sphingolipid metabolism in central and peripheral nervous tissues in 3-month-old HspS139F mice. Though sphingolipid levels were not altered in sciatic nerves from HspS139F mice, ceramides and deoxyceramides, as well as sphingomyelins (SMs) were elevated in brain tissues from HspS139F mice. Histology was utilized to further characterize HspS139F mice. HspS139F mice exhibited no alterations to the expression and phosphorylation of neurofilaments, or in the expression of acetylated α-tubulin in the brain or sciatic nerve. Interestingly, HspS139F mice demonstrated cerebellar demyelination. Locomotor function, grip strength and gait were examined to define the role of HspS139F in the clinical phenotypes associated with CMT2F. Gait analysis revealed no differences between HspWT and HspS139F mice. However, both coordination and grip strength were decreased in 3-month-old HspS139F mice. Together these data suggest that the endogenous S139F mutation in HSPB1 may serve as a mouse model for hereditary and sensory neuropathies such as CMT2F.

Scientific and Regulatory Policy Committee Technical Review: Biology and Pathology of Ganglia in Animal Species Used for Nonclinical Safety Testing.

Dorsal root ganglia (DRG), trigeminal ganglia (TG), other sensory ganglia, and autonomic ganglia may be injured by some test article classes, including anti-neoplastic chemotherapeutics, adeno-associated virus-based gene therapies, antisense oligonucleotides, nerve growth factor inhibitors, and aminoglycoside antibiotics. This article reviews ganglion anatomy, cytology, and pathology (emphasizing sensory ganglia) among common nonclinical species used in assessing product safety for such test articles (TAs). Principal histopathologic findings associated with sensory ganglion injury include neuron degeneration, necrosis, and/or loss; increased satellite glial cell and/or Schwann cell numbers; and leukocyte infiltration and/or inflammation. Secondary nerve fiber degeneration and/or glial reactions may occur in nerves, dorsal spinal nerve roots, spinal cord (dorsal and occasionally lateral funiculi), and sometimes the brainstem. Ganglion findings related to TA administration may result from TA exposure and/or trauma related to direct TA delivery into the central nervous system or ganglia. In some cases, TA-related effects may need to be differentiated from a spectrum of artifactual and/or spontaneous background changes.

Cardiovascular autonomic neuropathy in patients with type 2 diabetes with and without sensorimotor polyneuropathy.

BACKGROUND AND AIMS: Cardiovascular autonomic neuropathy (CAN) in patients with diabetes is associated with poor prognosis. We aimed to assess signs of CAN and autonomic symptoms and to investigate the impact of sensorimotor neuropathy on CAN by examining type 2 diabetes patients with (DPN [distal sensorimotor polyneuropathy]) and without distal sensorimotor polyneuropathy (noDPN) and healthy controls (HC). Secondarily, we aimed to describe the characteristics of patients with CAN. METHODS: A population of 374 subjects from a previously described cohort of the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) were included. Subjects were examined with the Vagus™ device for the diagnosis of CAN, where two or more abnormal cardiovascular autonomic reflex tests indicate definite CAN. Autonomic symptoms were assessed with Composite Autonomic Symptom Score 31 (COMPASS 31) questionnaire. DPN was defined according to the Toronto consensus panel definition. RESULTS: Definite CAN was present in 22% with DPN, 7% without DPN and 3% of HC, and 91% of patients with definite CAN had DPN. Patients with DPN and definite CAN reported higher COMPASS 31 scores compared to patients with noDPN (20.0 vs. 8.3, p < 0.001) and no CAN (22.1 vs. 12.3, p = 0.01). CAN was associated with HbA1c and age in a multivariate logistic regression analysis but was not associated with IEFND or triglycerides. INTERPRETATION: One in five patients with DPN have CAN and specific CAN characteristics may help identify patients at risk for developing this severe diabetic complication. Autonomic symptoms were strongly associated with having both DPN and CAN, but too unspecific for diagnosing CAN.

Plasma neurofilament light chain concentrations are elevated in youth-onset type 2 diabetes and associated with neuropathy.

BACKGROUND AND AIMS: The lack of easily measurable biomarkers remains a challenge in executing clinical trials for diabetic neuropathy (DN). Plasma Neurofilament light chain (NFL) concentration is a promising biomarker in immune-mediated neuropathies. Longitudinal studies evaluating NFL in DN have not been performed. METHODS: A nested case-control study was performed on participants with youth-onset type 2 diabetes enrolled in the prospective Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study. Plasma NFL concentrations were measured at 4-year intervals from 2008 to 2020 in 50 participants who developed DN and 50 participants with type 2 diabetes who did not develop DN. RESULTS: NFL concentrations were similar in the DN and no DN groups at the first assessment. Concentrations were higher in DN participants at all subsequent assessment periods (all p < .01). NFL concentrations increased over time in both groups, with higher degrees of change in DN participants (interaction p = .045). A doubling of the NFL value at Assessment 2 in those without DN increased the odds of ultimate DN outcome by an estimated ratio of 2.86 (95% CI: [1.30, 6.33], p = .0046). At the final study visit, positive Spearman correlations (controlled for age, sex, diabetes duration, and BMI) were observed between NFL and HbA1c (0.48, p < .0001), total cholesterol (0.25, p = .018), and low-density lipoprotein (LDL (0.30, p = .0037)). Negative correlations were observed with measures of heart rate variability (-0.42 to -0.46, p = <.0001). INTERPRETATION: The findings that NFL concentrations are elevated in individuals with youth-onset type 2 diabetes, and increase more rapidly in those who develop DN, suggest that NFL could be a valuable biomarker for DN.