Diabetes and cardiac autonomic neuropathy: Clinical manifestations, cardiovascular consequences, diagnosis and treatment

Sequential classification approach for enhancing the assessment of cardiac autonomic neuropathy

Cardiac autonomic neuropathy (CAN) is a progressive condition associated with chronic diseases like diabetes, requiring regular reviews. Current CAN diagnostic methods are often time-consuming and lack precision. This study presents a novel, two-stage classification model designed to improve CAN diagnostic efficiency. Using a dataset of 1335 patient entries, including inflammatory markers and autonomic function tests (CARTs), the model first classifies patients based on six inflammatory markers- Interleukin-6 (IL-6), C-reactive protein (CRP), Interleukin-1 beta (IL-1beta), Interleukin-10 (IL-10), Monocyte Chemoattractant Protein-1 (MCP-1), and Insulin-like growth factor-1 (IGF-1). In this initial stage, the model achieves 0.893 accuracy for 31.46% of cases in the three-class CAN model at a 0.80 threshold. For cases requiring further assessment, the second stage incorporates CARTs, improving overall accuracy to 0.933. Notably, 98.87% of cases are accurately classified using only a subset of CARTs, with just 1.12% needing all five tests. Additionally, we developed a web application that utilizes Shapley plots to visualize and explain the contribution of each marker, facilitating interpretation for clinical use. This two-stage approach underscores the diagnostic relevance of inflammatory markers, providing clinicians with a streamlined, resource-efficient tool for timely CAN diagnosis and intervention.

SGLT-2 inhibitors on cardiac autonomic function in individuals with and without type 2 diabetes mellitus

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors have emerged as key therapeutic agents in managing type 2 diabetes mellitus (T2DM) and obesity, offering benefits that extend beyond glycemic control. This review examines the role of SGLT-2 inhibitors in modulating cardiac autonomic function, with a particular focus on heart rate variability (HRV) as a biomarker of autonomic balance. These agents improve metabolic profiles through enhanced glucosuria, natriuresis, and weight loss, while concurrently reducing blood pressure. Importantly, they also attenuate sympathetic nervous system overactivity and promote parasympathetic modulation, which may lower the risk of adverse cardiovascular events. The underlying mechanisms include not only the metabolic effects but also anti-inflammatory and antioxidative actions, which together contribute to improved endothelial function and vascular health. Advanced HRV analyses, encompassing traditional time and frequency domain methods as well as nonlinear approaches, have proven valuable in detecting early autonomic dysfunction in high-risk populations. Some studies suggest that SGLT-2 inhibitors may be associated with improvements in HRV parameters, such as increased SDNN and RMSSD and a reduced LF/HF ratio. However, findings are inconsistent across studies, and further research is needed to determine the extent and mechanisms of these potential effects. Although these findings are promising, further standardized, long-term studies are essential to clarify the mechanisms and optimal therapeutic strategies involving SGLT-2 inhibitors in the management of autonomic dysfunction. Future research should also explore the synergistic potential of combining SGLT-2 inhibitors with other cardiometabolic therapies to enhance cardiovascular outcomes in individuals with and without T2DM.

Blunted cardiovascular responses in individuals with type 2 diabetes and hypertension during cold and heat exposure

Introduction

The effect of type 2 diabetes (T2D) on indices of cardiovascular function during exposure to cold or hot environmental temperatures is not well known. Therefore, the aim of our study was to assess the effect of short-term whole-body cold and heat exposure on the cardiovascular responses in individuals with T2D.

Material and methods

10 participants with T2D and hypertension (mean age 64 ± 4 years) and 10 controls (mean age 63 ± 5 years) underwent 90 min of whole-body exposure to cold (10°C; 10% relative humidity) and heat (40°C; 50% relative humidity) in a randomized sequence on differing days. Central and brachial blood pressure (BP), heart rate (HR), and skin blood flow were measured before, during, and after the exposure.

Results

During cold exposure, subjects with T2D exhibited a smaller increase in central (14 (CI 95%:3, 23) vs. 43 (CI 95%:32, 53) mmHg, p < 0.05) and brachial systolic BP (12 (CI 95%:1, 22)) vs. 40 (CI 95%:30, 51) mmHg, p < 0.05) compared to controls. The corresponding reduction in HR in the cold was also less in T2D compared to controls (5 (CI 95%: 10, 0.02) vs. 9 (CI 95%: 14, -4) bpm, p < 0.05). Heat exposure reduced central and brachial BP similarly in both groups. However, the heat-related increase in HR was less pronounced in T2D subjects compared to controls (7 (CI 95%:1, 13) vs. 14 (CI 95%: 9, 19) bpm, p < 0.05). Finally, the magnitude of the increase in skin blood flow was less in the heat in T2D subjects (+210 (CI 95%: 41, 461) vs. +605 (CI 95%: 353, 855) PU, p < 0.05).

Discussion

T2D attenuated cardiovascular responses, such as BP and HR during short-term exposure to cold, and HR and skin blood flow during short-term exposure to heat. These observations suggest impaired capacity to respond to environmental temperature extremes in individuals with T2D.

Diabetic neuropathy: cutting-edge research and future directions

Diabetic neuropathy (DN) is a prevalent and debilitating complication of diabetes mellitus, significantly impacting patient quality of life and contributing to morbidity and mortality. Affecting approximately 50% of patients with diabetes, DN is predominantly characterized by distal symmetric polyneuropathy, leading to sensory loss, pain, and motor dysfunction, often resulting in diabetic foot ulcers and lower-limb amputations. The pathogenesis of DN is multifaceted, involving hyperglycemia, dyslipidemia, oxidative stress, mitochondrial dysfunction, and inflammation, which collectively damage peripheral nerves. Despite extensive research, disease-modifying treatments remain elusive, with current management primarily focusing on symptom control. This review explores the complex mechanisms underlying DN and highlights recent advances in diagnostic and therapeutic strategies. Emerging insights into the molecular and cellular pathways have unveiled potential targets for intervention, including neuroprotective agents, gene and stem cell therapies, and innovative pharmacological approaches. Additionally, novel diagnostic tools, such as corneal confocal microscopy and biomarker-based tests, have improved early detection and intervention. Lifestyle modifications and multidisciplinary care strategies can enhance patient outcomes. While significant progress has been made, further research is required to develop therapies that can effectively halt or reverse disease progression, ultimately improving the lives of individuals with DN. This review provides a comprehensive overview of current understanding and future directions in DN research and management.

Biochanin A Mitigates Oxidative Stress and Inflammation in Diabetic Myocardial Infarction: Insights From a Streptozotocin and Isoproterenol Rat Model

INTRODUCTION

 Diabetes mellitus (DM) significantly increases the risk and severity of myocardial infarction (MI), contributing to poor cardiovascular outcomes through oxidative stress, inflammation, and endothelial dysfunction.

METHODS

 This study evaluates the cardioprotective potential of biochanin A (BCA), a naturally occurring isoflavonoid with antioxidant and anti-inflammatory properties, in a streptozotocin (STZ) and isoproterenol (ISO)-induced model of diabetic myocardial infarction (DMI) in rats. Male Wistar rats were divided into five groups, including normal controls, STZ+ISO, and three BCA-treated groups (5, 10, and 20 mg/kg).  Results: BCA administration significantly improved electrocardiographic parameters by reducing ST height and QT interval prolongation (p < 0.05). It also reduced myocardial injury markers (lactate dehydrogenase (LDH), creatinine kinase on myocardial bundle (CK-MB), aspartate transaminase (AST), and cardiac troponin-T (cTn-T)) in a dose-dependent manner (p < 0.001). BCA normalized blood pressure, heart rate, and left ventricular function, improving maximum and minimum rate of ventricular contraction (+dP/dt, -dP/dt) (p < 0.01). Furthermore, BCA significantly decreased blood glucose levels and improved lipid profiles by lowering total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL) while increasing high-density lipoprotein (HDL) levels (p < 0.001). It suppressed inflammation by reducing tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β levels (p < 0.01). Oxidative stress markers, including malondialdehyde (MDA), were reduced, while antioxidant markers such as glutathione (GSH), superoxide dismutase (SOD), and catalase were increased (p < 0.001). BCA enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) expression, promoting antioxidant defense. Histopathological analysis confirmed reduced myocardial injury and improved cardiac architecture.  Conclusion: These findings highlight BCA's potential as a therapeutic agent for managing DMI through its dual antioxidant and anti-inflammatory actions.

Diabetic Cardiomyopathy: What Clinicians Should Know

Diabetes has classically been associated with atherosclerotic cardiovascular disease. However, heart failure is now increasingly recognized as a prevalent and often first cardiovascular complication among patients with diabetes. Investigation of this epidemiological relationship has led to recognition of diabetic cardiomyopathy, or structural heart disease that develops in patients with diabetes and may lead to progressive heart failure independently of coronary artery disease or conventional cardiovascular risk factors such as hypertension. Despite increased awareness, clinical management of this common cardiovascular complication remains challenging, with no consensus on its diagnosis or treatment. The lack of specific therapy has been recognized as an unmet clinical need. In this review, we summarize current understanding of the hallmark metabolic and structural changes of diabetic cardiomyopathy, appraise current tools for diagnosis and staging among patients, and describe the emerging but still preclinical data on therapeutic options.

The assessment of autonomic nervous function in patients with gastrointestinal malignancies and its relationship with clinical characteristics

Introduction

The gastrointestinal tract is the organ most extensively distributed by autonomic nerves, and researches have indicated a relationship between automatic nerves and the progression of gastrointestinal cancers. This study aimed to evaluate the autonomic nervous function in patients with gastrointestinal cancer and to explore its relationship with clinical characteristics.

Methods

We employed the Composite Autonomic Symptom Score 31 (COMPASS-31) questionnaire and cardiovascular autonomic reflex tests (CARTs) to evaluate autonomic nervous function, while also conducting a thorough analysis of clinical data.

Results

Our results showed that low white blood cell (WBC) count (OR = 0.461, 95% CI: 0.218-0.976, p = 0.043) and increased maximum tumor diameter (OR = 1.619, 95% CI: 1.025-2.555, p = 0.039) were risk factors for autonomic dysfunction according to the COMPASS-31 assessment. While hypertension (OR = 5.747, 95% CI: 1.186-27.862, p = 0.030) and elevated platelet-to-albumin ratio (PAR) (OR = 1.256, 95% CI: 1.025-1.540, p = 0.028) were identified as independent risk factors for autonomic dysfunction based on the CARTs results. Combining the findings from COMPASS-31 and CARTs revealed that older age (OR = 1.133, 95% CI: 1.015-1.264, p = 0.027) and vascular invasion (OR = 7.706, 95% CI: 1.391-42.684, p = 0.019) were also independent risk factors for autonomic dysfunction.

Conclusion

Our findings reveal that these specific factors related to gastrointestinal cancers significantly influence autonomic nervous function. It is essential to evaluate autonomic nervous function and its associated risk factors in patients with gastrointestinal malignancies, which provide new insights into the intervention strategies for cancer diseases.

Investigating the Visit-to-visit Repeatability of Autonomic Neuropathy Assessment Measures in Healthy Subjects

Background

Autonomic neuropathy assessment is needed for the diagnosis and prognostication of different clinical disorders. Heart rate variability (HRV) and autonomic reactivity assessment by Ewing's battery of tests form the cornerstones of laboratory assessment of cardiac autonomic neuropathy evaluation.

Purpose

While these tests are routinely used, there are conflicting reports regarding the visit-to-visit repeatability of these tests. Therefore, we assessed autonomic measures derived using aforementioned tests on multiple visits in healthy subjects.

Methods

We enrolled 31 healthy subjects and performed autonomic function evaluation on five visits by assessment of HRV and autonomic reactivity on day 1 forenoon and afternoon, next day, one week later and one month later. Repeatability assessment was evaluated using Intraclass correlation coefficients. Values were defined as moderate, good and excellent based on previously reported criteria.

Results

Thirty-one subjects completed all five visits (17 males, 14 females; mean age = 29 ± 5.44 years). While time-domain measures demonstrated good to excellent repeatability, frequency-domain measures were only moderately repeatable. Autonomic reactivity indices also displayed good to excellent repeatability with the exception of blood pressure response to orthostatic challenge which was moderately repeatable.

Conclusion

We recommend that sole reliance on frequency domain metrics for HRV assessment should be avoided. HRV indices and autonomic reactivity measures may continue to be used for cardiac autonomic neuropathy assessment.

Cardiac Autonomic Neuropathy in Diabetes Mellitus: Pathogenesis, Epidemiology, Diagnosis and Clinical Implications: A Narrative Review

Background: Cardiac autonomic neuropathy (CAN) is a serious but sometimes underdiagnosed complications of Diabetes Mellitus (DM). Because of the subtle onset and non-specific symptoms that can be mistaken for other conditions, CAN is frequently underdiagnosed despite the serious consequences that can appear. Its significance as an independent risk factor for cardiovascular events, including arrhythmias, sudden cardiac death, and silent myocardial ischemia, is being demonstrated by recent studies. The objective of this review article is to highlight the reasons why CAN is underdiagnosed and its association with decreased cardiovascular risk and promote clinical awareness. This review article summarizes the epidemiology, influence on the cardiovascular system and diagnostic methods of CAN, and the clinical implications of diabetic neuropathy. This review analyzes available data from papers relevant to the topic of diabetic neuropathy, cardiac autonomic neuropathy, and cardiovascular system implications. Conclusions: CAN is still underdiagnosed despite its clinical impact because routine screening is lacking, and healthcare providers are not aware of it. To improve outcomes for people with DM, it is necessary to introduce standardized diagnostic procedures into clinical practice and increase the knowledge about CAN.

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.

Effects of Revascularization on Cardiac Autonomic Neuropathy in Type 2 Diabetes Mellitus Patients With Chronic Stable Angina

BACKGROUND

Type 2 diabetes mellitus (T2DM) leads to cardiac autonomic neuropathy (CAN), affecting blood flow and heart rate regulation eventually causing chronic stable angina (CSA). Percutaneous coronary intervention (PCI) can correct autonomic dysfunctions and improve myocardial perfusion. This study aimed to assess CAN using heart rate variability (HRV) and cardiovascular reflex tests in T2DM patients with CSA before and after PCI.

MATERIAL AND METHODS

From cardiology outpatient clinics, 30 patients with T2DM with CSA were recruited. Before and after PCI, the following HRV parameters like low frequency (LF), high frequency (HF), LF:HF ratio, total power (TP), square root of mean square differences of successive R-R intervals (RMSSD), standard deviation of normal R-R intervals (SDNN), and percentage of adjacent NN intervals that differ from each other by more than 50 seconds (pNN50) were measured for every patient. Cardiovascular reflex tests, including the deep breathing test, the isometric handgrip test, the 30:15 ratio, the Valsalva ratio, and the lying-to-standing test (LST), were performed on the patients both before and after PCI. SPSS version 21.0 (IBM Corp., Armonk, NY), a licensed statistical program, was used to compile and analyze the data.

RESULTS

When compared to the pre-PCI group, 30 patients with T2DM with CSA, age range between 45 and 70 years, both genders demonstrated a significant increase in post-PCI HRV frequency domain parameters, such as LF (239.52±67.21ms2 vs. 307.62±74.17 ms2) and HF (249±25.21 ms2 vs. 379.67±76.55 ms2). The time domain parameters showed a significant increase in post-PCI values compared to pre-PCI values. These included RMSSD (33.97±3.96 ms vs. 8.005±3.25 ms), SDNN (41.4±9.78 vs. 31.74±7.04ms), NN50 (13.241±3.07 vs. 5.20±6.63), and TP (1130.08±320.10 ms2 vs. 754.54±96.93 ms2). In cardiovascular reflex tests, pre-PCI groups had significantly lower delta HR (DBT) (10.47±1.76 bpm vs. 14.20±2.09), E:I ratio (DBT) (1.14±0.042 vs. 1.20±0.026), and Valsalva ratio (1.10±0.071 vs. 1.22±0.084) than post-PCI groups. The pre-PCI group showed a substantial decrease in both the systolic blood pressure (LST) (-6.13±4.85 mmHg vs. -1.01±3.63 mmHg) and the 30:15 ratio (1.13±0.074 vs. 1.09±0.067) when compared to the post-PCI group. The handgrip test (18.73±4.31 mmHg vs. 15.31±4.27 mmHg) did not yield statistically significant results.

CONCLUSIONS

Before PCI, T2DM patients with CSA experienced autonomic dysfunction, but after revascularization, their functions improved by reestablishing basal cardiac autonomic tone and autonomic reactivity. HRV and cardiovascular reflex tests are useful noninvasive tools for assessing CAN and stratifying a prospective risk factor for estimating the morbidity and death from cardiovascular illnesses in T2DM with CSA.

Prevalence of cardiovascular autonomic neuropathy in an admixed population of patients with type 1 diabetes. Lessons from a pioneer multicentre study in Brazil

AIMS

To evaluate the prevalence of cardiovascular autonomic neuropathy (CAN) and its associated factors in Brazilian patients with type 1 diabetes (T1D).

METHODS

This cross-sectional, multicentre study was conducted in 14 public clinics in ten Brazilian cities. From 1760 patients, 1712 were included (97.3 %): 953 females (55.7 %), 930 (54.3 %) Caucasians, aged 29.9 ±11.9 years and with diabetes duration of 15.4 ± 9.2 years. CAN was evaluated using cardiovascular autonomic reflex tests.

RESULTS

The prevalence of CAN was 23.4 %. Multivariable hierarchical logistic regression showed CAN associated with age, smoking, lower socioeconomic status, higher yearly medical appointments, insulin therapeutic regimens, higher levels of HbA1c, total cholesterol, uric acid, diastolic blood pressure and heart rate, presence of retinopathy, diabetic kidney disease and a tendency to be associated with severe hypoglycemia. Lower health-related quality of life was also found in univariate analysis in these patients.

CONCLUSIONS

Patients with T1D presented an important prevalence of CAN that was associated with other diabetes-related chronic complications, and also with demographic, clinical and laboratorial traditional risk factors. Considering lack of formal policy, our data could be used for guiding public health approach to awareness and CAN's screening, diagnosis and clinical management in patients with T1D in Brazil.

Effects of adipose tissues on the relationship between type 2 diabetes mellitus and reduced heart rate variability: mediation analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with decreased heart rate variability (HRV) with an unclear intermediate mechanism. This study aimed to conduct mediation analysis to explore the impact of various adipose tissues on the relationship between T2DM and HRV.

METHODS

A total of 380 participants were enrolled for analysis, including 249 patients with T2DM and 131 non-diabetic controls. The thicknesses of four adipose tissues (subcutaneous, extraperitoneal, intraperitoneal, and epicardial) were measured by abdominal ultrasound or echocardiography respectively. HRV was assessed by 24-hour Holter for monitoring both frequency domain indices (LF, HF, and LF/HF) and time domain indices (SDNN, SDANN, SDNN index, rMSSD and pNN50). Mediation analysis was used toexamine whether adipose tissues mediated the relationship between T2DM and each index of HRV. Then, a latent variable - HRV burden - was constructed by structural equation model with selected HRV indices to comprehensively assess the whole HRV.

RESULTS

Compared to non-diabetic controls, patients with T2DM exhibited a significant reduction in indices of HRV, and a remarkable increase in the thicknesses of extraperitoneal, intraperitoneal, and epicardial adipose tissues. Mediation analysis found significant indirect effects of T2DM on six indices of HRV, including HF, SDNN, SDANN, SDNN index, rMSSD, and pNN50, which was mediated by epicardial adipose tissue rather than other adipose tissues, with the mediation proportions of 64.21%, 16.38%, 68.33%, 24.34%, 24.10% and 30.51%, respectively. Additionally, epicardial adipose tissue partially mediated the relationship between T2DM and reduced HRV burden (24.26%), which composed by SDNN, SDNN index, rMSSD, and pNN50.

CONCLUSION

Epicardial adipose tissue partially mediated the relationship between T2DM and reduced HRV, which reinforces the value of targeting heart-specific visceral fat to prevent cardiac autonomic neuropathy in diabetes.

Cardiac Autonomic Neuropathy Is Not Associated with Apolipoprotein E Gene Isoforms in the Kazakh Population: A Case-Control Study

The absence of an early diagnosis of cardiac autonomic neuropathy might increase the risk of the disease, progressing to an irreversible stage. Therefore, this study aims to investigate the APOE gene isoforms in patients with cardiac autonomic neuropathy to identify early markers for predicting this disease in the Kazakh population. A total of 147 patients with cardiac neuropathy and 153 controls were examined in this case-control study. Patients were genotyped for two polymorphisms of the APOE gene using real-time PCR. Statistical calculations were performed using binary logistic regression. As a result of our study, we found that there was no statistically significant difference in the frequency of any APOE gene isoforms (APOE (ε2/ε2), APOE (ε2/ε3), APOE (ε2/ε4), APOE (ε3/ε3), or APOE (ε4/ε4)) between the patient group and the control group (p = 0.69, p = 0.64, p = 0.19, p = 0.22, p = 0.97, respectively). Thus, cardiac autonomic neuropathy is not associated with APOE gene isoforms in the Kazakh population.

Prevalence and Risk Factors of Cardiovascular Autonomic Neuropathy in Individuals with Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Background

Cardiac autonomic neuropathy (CAN) is a severe complication of type 1 diabetes mellitus (T1DM). This meta-analysis aimed to synthesize relevant literature on the prevalence of CAN and its risk factors in individuals with T1DM.

Methods

We screened relevant literature from databases based on predefined search criteria until June 28, 2022. Data extraction and quality assessment were conducted independently by two reviewers. A meta-analysis was conducted to determine the prevalence of CAN and its risk factors in individuals with T1DM using a random-effects model. A subgroup analysis was conducted to assess variations in CAN prevalence based on diabetes duration, diagnostic criteria, study quality, study design, and geographic region of the participants.

Results

A total of 21 studies provided information on the prevalence of CAN, while 18 studies explored the potential risk factors for CAN. The overall estimated prevalence of CAN in individuals with T1DM was 25.8% (95% confidence interval (95% CI): 0.208-0.307), with no significant differences observed among the five regions. Additionally, smoking, lipid abnormalities, hypertension, duration of diabetes, increased body mass index, elevated glycated haemoglobin concentrations, and presence of chronic complications of diabetes, such as diabetic retinopathy, diabetic neuropathy, and diabetic nephropathy, were associated with a higher prevalence of CAN in individuals with diabetes.

Conclusions

CAN is prevalent in individuals with T1DM worldwide. Efforts should be made to improve early screening and intervention for CAN, as well as to implement strategies aimed at improving or controlling early risk factors associated with CAN.

Composite Autonomic Symptom Score-31 for the diagnosis of cardiovascular autonomic dysfunction in long-term coronavirus disease 2019

BACKGROUND

Composite Autonomic Symptom Score-31 (COMPASS-31) is an easy-to-use screening tool for the evaluation of autonomic dysfunction in various diseases affecting neural function but has rarely been used in the assessment of long coronavirus disease 2019 (COVID-19). This study aimed to evaluate the diagnostic accuracy of the COMPASS-31 score in detecting dysfunction of the autonomic nervous system in patients 3 months after COVID-19 infection.

MATERIALS AND METHODS

Fifty-nine subjects were recruited and grouped into 2: (a) controls (n = 31) who had never had positive polymerase chain reaction results for COVID-19 before and (b) the post-COVID-19 patients (n = 28) who had confirmed COVID-19 infection 3-6 months before recruitment. COMPASS-31 questionnaire was utilized to evaluate subjective symptoms or evidence of autonomic dysfunction. Autonomic dysfunction was assessed objectively by cardiovascular autonomic reflex tests (CARTs) and heart rate variability (HRV). For comparison of quantitative variables between two groups, t-test or Mann-Whitney U test, as appropriate, were used. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), negative likelihood ratio (LR), and positive LR were used as measures of diagnostic accuracy. Receiver operating characteristic (ROC) curve analysis determined the overall accuracy of COMPASS-31.

RESULTS

The median COMPASS score was found to be significantly higher in post-COVID-19 participants than controls (15.5 vs. 10, P = 0.021). The median total CART score was also significantly higher in post-COVID-19 participants (0 vs. 1, P < 0.001). Out of 6 domains of the COMPASS score, the median value for orthostatic dysfunction was found to be significantly higher in post-COVID-19 participants than controls (12 vs. 0, P = 0.008). There was significantly fair accuracy of the COMPASS score with an area under the receiver operating curve 0.68 (0.54-0.82) following the total CART score ≥2 as the gold standard in the diagnosis of autonomic dysfunction (P = 0.021). The best cutoff point of the total COMPASS score was 12.5, where the optimal values of sensitivity, specificity, and positive and negative predictive values were achieved. Nonsignificant and weak correlations between CARTs, HRV parameters, and COMPASS score were found.

CONCLUSION

COMPASS-31 could be used as a user-friendly screening tool to detect autonomic dysfunction in post-COVID-19 cases with acceptable sensitivity and specificity.

The emotion paradox in the aging body and brain

With age, parasympathetic activity decreases, while sympathetic activity increases. Thus, the typical older adult has low heart rate variability (HRV) and high noradrenaline levels. Younger adults with this physiological profile tend to be unhappy and stressed. Yet, with age, emotional experience tends to improve. Why does older adults' emotional well-being not suffer as their HRV decreases? To address this apparent paradox, I present the autonomic compensation model. In this model, failing organs, the initial phases of Alzheimer's pathology, and other age-related diseases trigger noradrenergic hyperactivity. To compensate, older brains increase autonomic regulatory activity in the pregenual prefrontal cortex (PFC). Age-related declines in nerve conduction reduce the ability of the pregenual PFC to reduce hyperactive noradrenergic activity and increase peripheral HRV. But these pregenual PFC autonomic compensation efforts have a significant impact in the brain, where they bias processing in favor of stimuli that tend to increase parasympathetic activity (e.g., stimuli that increase feelings of safety) and against stimuli that tend to increase sympathetic activity (e.g., threatening stimuli). In summary, the autonomic compensation model posits that age-related chronic sympathetic/noradrenergic hyperactivity stimulates regulatory attempts that have the side effect of enhancing emotional well-being.

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.

Perioperative changes of serum orphanin in diabetic patients and its relationship with sympathetic nervous system

The occurrence of cardiovascular events in diabetic patients during the perioperative period is related to the activation of sympathetic nerves. Basic research shows that serum nociceptin/orphanin FQ (N/OFQ) levels in diabetic neuropathy rats increased, and N/OFQ reduces the release of norepinephrine (NE). We hypothesize that N/OFQ will affect the sympathetic nervous system during perioperative myocardium of diabetic patients. 66 patients with unilateral knee arthroplasty were divided into diabetes group (D group) and non-diabetes group (N group). Measured blood glucose, serum NE, N/OFQ concentrations at the 30 min before anesthesia (T0), 1 h after surgery (T1), 24 h after surgery (T2) and the cardiac troponinI (cTnI) concentration at T0 and T2. Compared with N group, the concentration of blood glucose, N/OFQ and cTnI in D group was higher and the NE was lower at T0 (P < 0.05). At T1, the blood glucose, N/OFQ, NE concentrations of D group increased, only the blood glucose increased in N group (P < 0.05). Serum N/OFQ of D group from T0 to T1 was correlated with the change trend of blood glucose, NE concentration from T0 to T1 and cTnI from T0 to T2(r = 0.386, P = 0.027; r = 0.350, P = 0.046; r = 0.363, P = 0.038). The outcomes demonstrated that the preoperative serum N/OFQ concentration in diabetic patients was increased, and the increase in N/OFQ concentration during the operation was related to the increase in NE and cTnI concentrations, perioperative N/OFQ may mediate myocardial injury through sympathetic nervous system.

Harnessing the Synergy of SGLT2 Inhibitors and Continuous Ketone Monitoring (CKM) in Managing Heart Failure among Patients with Type 1 Diabetes

Heart failure (HF) management in type 1 diabetes (T1D) is particularly challenging due to its increased prevalence and the associated risks of hospitalization and mortality, driven by diabetic cardiomyopathy. Sodium-glucose cotransporter-2 inhibitors (SGLT2-is) offer a promising avenue for treating HF, specifically the preserved ejection fraction variant most common in T1D, but their utility is hampered by the risk of euglycemic diabetic ketoacidosis (DKA). This review investigates the potential of SGLT2-is in T1D HF management alongside emergent Continuous Ketone Monitoring (CKM) technology as a means to mitigate DKA risk through a comprehensive analysis of clinical trials, observational studies, and reviews. The evidence suggests that SGLT2-is significantly reduce HF hospitalization and enhance cardiovascular outcomes. However, their application in T1D patients remains limited due to DKA concerns. CKM technology emerges as a crucial tool in this context, offering real-time monitoring of ketone levels, which enables the safe incorporation of SGLT2-is into treatment regimes by allowing for early detection and intervention in the development of ketosis. The synergy between SGLT2-is and CKM has the potential to revolutionize HF treatment in T1D, promising improved patient safety, quality of life, and reduced HF-related morbidity and mortality. Future research should aim to employ clinical trials directly assessing this integrated approach, potentially guiding new management protocols for HF in T1D.

Progress in Cardiac Magnetic Resonance Feature Tracking for Evaluating Myocardial Strain in Type-2 Diabetes Mellitus

The global prevalence of type-2 diabetes mellitus (T2DM) has caused harm to human health and economies. Cardiovascular disease is one main cause of T2DM mortality. Increased prevalence of diabetes and associated heart failure (HF) is common in older populations, so accurately evaluating heart-related injury and T2DM risk factors and conducting early intervention are important. Quantitative cardiovascular system imaging assessments, including functional imaging during cardiovascular disease treatment, are also important. The left-ventricular ejection fraction (LVEF) has been traditionally used to monitor cardiac function; it is often preserved or increased in early T2DM, but subclinical heart deformation and dysfunction can occur. Myocardial strains are sensitive to global and regional heart dysfunction in subclinical T2DM. Cardiac magnetic resonance feature-tracking technology (CMR-FT) can visualize and quantify strain and identify subclinical myocardial injury for early management, especially with preserved LVEF. Meanwhile, CMR-FT can be used to evaluate the multiple cardiac chambers involvement mediated by T2DM and the coexistence of complications. This review discusses CMR-FT principles, clinical applications, and research progress in the evaluation of myocardial strain in T2DM.

The State of Cardiac Rehabilitation in Saudi Arabia: Barriers, Facilitators, and Policy Implications

Cardiovascular disease (CVD) is a critical public health issue in Saudi Arabia, where it is the leading cause of death. The economic burden of CVD in the country is expected to triple by 2035, reaching $9.8 billion. This paper provides an overview of CVD in Saudi Arabia and its risk factors, impact on healthcare, and effects on patients' quality of life. The review emphasizes the potential of cardiac rehabilitation (CR) programs in addressing the CVD epidemic. CR programs have been shown to reduce morbidity, mortality, and hospital readmissions while improving patients' cardiovascular health and overall well-being. However, these programs are underutilized and inaccessible in Saudi Arabia. The paper highlights the urgent need for CR programs in the country and suggests key strategies for implementation. These include increasing patient referrals, tailoring programs to individual needs, enhancing patient education, and making CR accessible through home-based options. Fostering multidisciplinary collaboration and developing tailored guidelines for Arab countries can further enhance the impact of CR programs. In conclusion, this review underscores the vital importance of comprehensive CR programs in Saudi Arabia to combat the rising CVD burden, improve patient quality of life, and align with the goals of the Saudi 2030 Vision for a healthier society.

Dermatoses in overweight and obese children and their relationship with insulin and skin color

BACKGROUND/AIM

The aim of the present study was to investigate the prevalence of obesity-related dermatoses in obese children, and the association between these dermatoses and insulin resistance as well as skin color.

METHODS

Obese, overweight, and normal weight children according to body mass index who were followed up and treated in the outpatient clinics were included in the study. Dermatological examinations of the participants were performed, and fasting insulin and glucose levels were checked.

RESULTS

The obese and overweight children were evaluated as the patient group (70 girls, 41 boys, mean age: 12.37 ± 3.14 years). One hundred one healthy children with normal weight were determined as the control group (59 girls, 42 boys, mean age: 12.15 ± 2.43). The first five common dermatoses in the patient group when compared with the control group were keratosis pilaris (KP), striae distensae, hyperhidrosis, acanthosis nigricans (AN), and plantar hyperkeratosis. The first five dermatoses which were positively correlated with formation and insulin resistance were KP, striae distensae, AN, hyperhidrosis, and plantar hyperkeratosis. According to the Fitzpatrick skin scale, we found that the darker the skin color, the higher the probability of AN and KP (OR, 0.298; 95% CI, 0.106-0.834, p = 0.021; OR, 0.306; 95% CI, 0.117-0.796, p = 0.015, respectively).

CONCLUSION

Some dermatoses associated with obesity and insulin resistance were not found in obese children, or there was no significant association. These results indicate that many skin morbidities may be prevented by preventing and treating obesity and insulin resistance in the early period.

Evaluating treatment options for cardiovascular autonomic neuropathy in patients with diabetes mellitus: a systematic review

Background

Cardiovascular autonomic neuropathy (CAN) is a debilitating complication of diabetes mellitus. To date, there is no systematic review on all the available drug treatments for CAN in diabetic patients, except for one review focusing on aldose reductase inhibitors.

Objective

To evaluate available drug treatment options for CAN in diabetic patients.

Methods

A systematic review was conducted with a search of CENTRAL, Embase, PubMed and Scopus from database inception till 14th May 2022. Randomised controlled trials (RCTs) of diabetic patients with CAN that investigated the effect of treatment on blood pressure, heart rate variability, heart rate or QT interval were included.

Results

Thirteen RCTs with a total of 724 diabetic patients with CAN were selected. There was a significant improvement in the autonomic indices of diabetic patients with CAN given angiotensin-converting enzyme inhibitor (ACEI) for 24 weeks (p<0.05) to two years (p<0.001), angiotensin-receptor blocker (ARB) for one year (p<0.05), single dose of beta blocker (BB) (p<0.05), omega-3 polyunsaturated fatty acids (PUFAs) for three months (p<0.05), alpha-lipoic acid (ALA) for four months (p < 0.05) to six months (p=0.048), vitamin B12 in combination with ALA, acetyl L‑carnitine (ALC), superoxide dismutase (SOD) for one year (p=0.001)  and near significant improvement in the autonomic indices of diabetic patients with CAN given vitamin E for four months (p = 0.05) compared to the control group. However, there was no significant improvement in the autonomic indices of patients given vitamin B12 monotherapy (p ≥ 0.05).

Conclusion

ACEI, ARB, BB, ALA, omega-3 PUFAs, vitamin E, vitamin B12 in combination with ALA, ALC and SOD could be effective treatment options for CAN, while vitamin B12 monotherapy might be unlikely to be recommended for the treatment of CAN due to its lack of efficacy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-023-00629-x.

Parasympathetic autonomic dysfunction is more often evidenced than sympathetic autonomic dysfunction in fluctuating and polymorphic symptoms of "long-COVID" patients

Several disabling symptoms potentially related to dysautonomia have been reported in "long-COVID" patients. Unfortunately, these symptoms are often nonspecific, and autonomic nervous system explorations are rarely performed in these patients. This study aimed to evaluate prospectively a cohort of long-COVID patients presenting severe disabling and non-relapsing symptoms of potential dysautonomia and to identify sensitive tests. Autonomic function was assessed by clinical examination, the Schirmer test; sudomotor evaluation, orthostatic blood pressure (BP) variation, 24-h ambulatory BP monitoring for sympathetic evaluation, and heart rate variation during orthostatism, deep breathing and Valsalva maneuvers for parasympathetic evaluation. Test results were considered abnormal if they reached the lower thresholds defined in publications and in our department. We also compared mean values for autonomic function tests between patients and age-matched controls. Sixteen patients (median age 37 years [31-43 years], 15 women) were included in this study and referred 14.5 months (median) [12.0-16.5 months] after initial infection. Nine had at least one positive SARS-CoV-2 RT-PCR or serology result. Symptoms after SARS-CoV-2 infection were severe, fluctuating and disabling with effort intolerance. Six patients (37.5%) had one or several abnormal test results, affecting the parasympathetic cardiac function in five of them (31%). Mean Valsalva score was significantly lower in patients than in controls. In this cohort of severely disabled long-COVID patients, 37.5% of them had at least one abnormal test result showing a possible contribution of dysautonomia to these nonspecific symptoms. Interestingly, mean values of the Valsalva test were significantly lower in patients than in control subjects, suggesting that normal values thresholds might not be appropriate in this population.

Cardiovascular autonomic neuropathy is associated with increased glycemic variability driven by hyperglycemia rather than hypoglycemia in patients with diabetes

AIM

Cardiac autonomic neuropathy (CAN) has been suggested to be associated with hypoglycemia and impaired hypoglycemia unawareness. We have assessed the relationship between CAN and extensive measures of glucose variability (GV) in patients with type 1 and type 2 diabetes.

METHODS

Participants with diabetes underwent continuous glucose monitoring (CGM) to obtain measures of GV and the extent of hyperglycemia and hypoglycemia and cardiovascular autonomic reflex testing.

RESULTS

Of the 40 participants (20 T1DM and 20 T2DM) (aged 40.70±13.73 years, diabetes duration 14.43±7.35 years, HbA1c 8.85±1.70%), 23 (57.5%) had CAN. Despite a lower coefficient of variation (CV) (31.26±11.87 vs. 40.33±11.03, P=0.018), they had a higher CONGA (8.42±2.58 vs. 6.68±1.88, P=0.024) with a lower median LBGI (1.60 (range: 0.20-3.50) vs. 4.90 (range: 3.20-7.40), P=0.010) and percentage median time spent in hypoglycemia (4 (range:4-13) vs. 1 (range:0-5), P=0.008), compared to those without CAN. The percentage GRADE_Euglycemia (3.30±2.78 vs. 5.69±3.09, P=0.017) and GRADE_Hypoglycemia (0.3 (range: 0 - 3.80) vs. 1.8 (range: 0.9-6.5), P=0.036) were significantly lower, while the percentage median GRADE_{Hyperglycemia} (95.45 (range:93-98) vs. 91.6 (82.8-95.1), P=0.013) was significantly higher in participants with CAN compared to those without CAN.

CONCLUSION

CAN was associated with increased glycemic variability with less time in euglycemia attributed to a greater time in hyperglycemia but not hypoglycemia.

Blood Pressure Variability in Clinical Practice: Past, Present and the Future

Recent advances in wearable technology through convenient and cuffless systems will enable continuous, noninvasive monitoring of blood pressure (BP), heart rate, and heart rhythm on both longitudinal 24-hour measurement scales and high-frequency beat-to-beat BP variability and synchronous heart rate variability and changes in underlying heart rhythm. Clinically, BP variability is classified into 4 main types on the basis of the duration of monitoring time: very-short-term (beat to beat), short-term (within 24 hours), medium-term (within days), and long-term (over months and years). BP variability is a strong risk factor for cardiovascular diseases, chronic kidney disease, cognitive decline, and mental illness. The diagnostic and therapeutic value of measuring and controlling BP variability may offer critical targets in addition to lowering mean BP in hypertensive populations.

Assessment of Hydration, Nutritional Status and Arterial Stiffness in Hypertensive Chronic Kidney Disease Patients

The aim of this cross-sectional study was to determine the body fluid volume in patients diagnosed with both chronic kidney disease (CKD) and arterial hypertension (AH), and to investigate the relationship between fluid overload (FO), nutritional status and arterial stiffness in this specific patient population. A total of 169 participants with CKD and AH were enrolled in the study, and data on general parameters, comorbidities, medication use, and laboratory parameters were collected. Body composition was assessed with a Tanita MC 780 device, and data on the central and peripheral systolic and diastolic blood pressure, as well as pulse wave velocity (PWV) and the augmentation index (AIx) were collected with an IEM Mobil-O-Graph 24 h ambulatory blood pressure monitor, which was based on oscillometry. The Mediterranean Diet Serving Score (MDSS) questionnaire was used to determine the adherence to the Mediterranean diet (MeDi). Our results showed that the significant positive predictors of hydration status were the use of diuretics and oral hypoglycemic agents, whereas the negative predictors were female sex, higher body mass index level and use of two or more antihypertensives in the form of a single-pill combination. We also found differences in blood pressure and arterial stiffness parameters in relation to volume status, along with differences based on the presence of diabetes mellitus (DM). In conclusion, these results call for a higher awareness of volume status in the care of CKD patients with AH, especially in those with diabetes mellitus.

The Role of Heart Rate Variability (HRV) in Different Hypertensive Syndromes

Cardiac innervation by the parasympathetic nervous system (PNS) and the sympathetic nervous system (SNS) modulates the heart rate (HR) (chronotropic activity) and the contraction of the cardiac muscle (inotropic activity). The peripheral vasculature is controlled only by the SNS, which is responsible for peripheral vascular resistance. This also mediates the baroreceptor reflex (BR), which in turn mediates blood pressure (BP). Hypertension (HTN) and the autonomic nervous system (ANS) are closely related, such that derangements can lead to vasomotor impairments and several comorbidities, including obesity, hypertension, resistant hypertension, and chronic kidney disease. Autonomic dysfunction is also associated with functional and structural changes in target organs (heart, brain, kidneys, and blood vessels), increasing cardiovascular risk. Heart rate variability (HRV) is a method of assessing cardiac autonomic modulation. This tool has been used for clinical evaluation and to address the effect of therapeutic interventions. The present review aims (a) to approach the heart rate (HR) as a CV risk factor in hypertensive patients; (b) to analyze the heart rate variability (HRV) as a "tool" to estimate the individual risk stratum for Pre-HTN (P-HTN), Controlled-HTN (C-HTN), Resistant and Refractory HTN (R-HTN and Rf-HTN, respectively), and hypertensive patients with chronic renal disease (HTN+CKD).

A Review on Autonomic Functional Assessment in Diabetic Patients

In today's world, science has progressed significantly, yet most people are still unaware of diabetes. Lack of obesity, physical work, and lifestyle changes are the main factors. Diabetes is becoming more common all around the globe. Type 2 diabetes may go unnoticed for years, resulting in serious consequences and high healthcare expenses. The goal of this study is to look at a wide range of studies in which the autonomic function of diabetic people has been studied with the help of various autonomic function tests (AFTs). AFT is a non-invasive approach to assessing patients for testing sympathetic and parasympathetic responses to stimuli. AFT findings give us comprehensive knowledge of the autonomic physiology reactions in normal and in autonomic diseases like diabetes. This review will concentrate on AFTs that are scientifically valid, trustworthy, and clinically beneficial, according to experts.

Heart rate variability in different sleep stages is associated with metabolic function and glycemic control in type 2 diabetes mellitus

Introduction: Autonomic nervous system (ANS) plays an important role in the exchange of metabolic information between organs and regulation on peripheral metabolism with obvious circadian rhythm in a healthy state. Sleep, a vital brain phenomenon, significantly affects both ANS and metabolic function. Objectives: This study investigated the relationships among sleep, ANS and metabolic function in type 2 diabetes mellitus (T2DM), to support the evaluation of ANS function through heart rate variability (HRV) metrics, and the determination of the correlated underlying autonomic pathways, and help optimize the early prevention, post-diagnosis and management of T2DM and its complications. Materials and methods: A total of 64 volunteered inpatients with T2DM took part in this study. 24-h electrocardiogram (ECG), clinical indicators of metabolic function, sleep quality and sleep staging results of T2DM patients were monitored. Results: The associations between sleep quality, 24-h/awake/sleep/sleep staging HRV and clinical indicators of metabolic function were analyzed. Significant correlations were found between sleep quality and metabolic function (|r| = 0.386 ± 0.062, p < 0.05); HRV derived ANS function showed strengthened correlations with metabolic function during sleep period (|r| = 0.474 ± 0.100, p < 0.05); HRV metrics during sleep stages coupled more tightly with clinical indicators of metabolic function [in unstable sleep: |r| = 0.453 ± 0.095, p < 0.05; in stable sleep: |r| = 0.463 ± 0.100, p < 0.05; in rapid eye movement (REM) sleep: |r| = 0.453 ± 0.082, p < 0.05], and showed significant associations with glycemic control in non-linear analysis [fasting blood glucose within 24 h of admission (admission FBG), |r| = 0.420 ± 0.064, p < 0.05; glycated hemoglobin (HbA1c), |r| = 0.417 ± 0.016, p < 0.05]. Conclusions: HRV metrics during sleep period play more distinct role than during awake period in investigating ANS dysfunction and metabolism in T2DM patients, and sleep rhythm based HRV analysis should perform better in ANS and metabolic function assessment, especially for glycemic control in non-linear analysis among T2DM patients.

Risk stratification of diabetic patients with unusual cardiac symptoms using a myocardial perfusion scan

BACKGROUND

Autonomic nervous system dysfunction in diabetic patients can result in an atypical presentation of cardiovascular disease that can be missed. We aimed to use single-photon emission computed tomography (SPECT) to assess cardiovascular disease (CAD) in diabetic patients with atypical pain to determine whether the pain above reflects the CAD.

METHOD

Diabetic patients with atypical cardiac symptoms were referred to the SPECT department. Demographic data such as age, gender, diabetes status, and other underlying diseases were gathered. A myocardial perfusion scan was then performed. The results were recorded to evaluate the risk of myocardial ischemia and the degree of coronary artery involvement in a non-invasive manner.

RESULTS

The study included 222 (177 female) subjects with mean ages of 63.01±11.62 and 59.41±9.19 in positive and negative SPECT, respectively. The most common symptoms were atypical chest pain (51.8%), followed by shortness of breath (50.5%), nausea, and syncope (0.9%). Cardiac parameters, such as the summed stress score (SSS), summed rest score (SRS), total perfusion deficit in stress (TPD-s), total perfusion deficit in rest (TPD-r), were significantly higher in the group with coronary artery involvement (P<0.001). However, ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volumes (ESV) parameters were not (P=.0.328, 0.351, and 0.443, respectively).

CONCLUSIONS

The mere presence of diabetes does not necessitate any additional diagnostic tests beyond those required for the general population, and it is possible to follow a diagnostic course similar to that of the general population.

Ferroptosis increases obesity: Crosstalk between adipocytes and the neuroimmune system

Ferroptosis requires not only the accumulation of iron ions, but also changes in many ferroptosis-related regulators, including a decrease in GPX4 and inhibition of SLC7A11 for classical ferroptosis, a deletion of FSP1 or GCH1. Surprisingly, adipose tissue (AT) in the obesity conditions is also accompanied by iron buildup, decreased GSH, and increased ROS. On the neurological side, the pro-inflammatory factor released by AT may have first caused ferroptosis in the vagus nerve by inhibiting of the NRF2-GPX4 pathway, resulting in disorders of the autonomic nervous system. On the immune side, obesity may cause M2 macrophages ferroptosis due to damage to iron-rich ATMs (MFe^hi) and antioxidant ATMs (Mox), and lead to Treg cells ferroptosis through reductions in NRF2, GPX4, and GCH1 levels. At the same time, the reduction in GPX4 may also trigger the ferroptosis of B1 cells. In addition, some studies have also found the role of GPX4 in neutrophil autophagy, which is also worth pondering whether there is a connection with ferroptosis. In conclusion, this review summarizes the associations between neuroimmune regulation associated with obesity and ferroptosis, and on the basis of this, highlights their potential molecular mechanisms, proposing that ferroptosis in one or more cells in a multicellular tissue changes the fate of that tissue.

Cardiac autonomic dysfunctions in type 2 diabetes mellitus: an investigative study with heart rate variability measures

Cardiac autonomic neuropathy (CAN) is a common yet underdiagnosed complication of Type 2 diabetes mellitus (T2DM). Heart rate variability (HRV), a sensitive diagnostic marker of cardiovascular risk, could help detect CAN at its earliest stage. However, the progression of CAN based on age and disease duration in T2DM is lacking. In this study, we propose to explore the occurrence of CAN in patients with varying stages and duration of T2DM. This cross-sectional study involves participants with T2DM (n = 160) and healthy volunteers (n = 40) with an age range of 30-60 years of both genders. Patients in the T2DM group were further subdivided into four subgroups based on their disease duration [Prediabetes, disease duration <5 yrs (D1), 5-10 yrs (D2), and >10 yrs (D3)]. All participants underwent short-term HRV recording for 20 minutes and analyzed for both time and frequency domain measures. The study results showed a significant increase in Heart Rate (HR) in D1 (P = 0.031) and D3 (P = 0.001) groups compared to healthy controls. The time-domain measures of HRV were significantly reduced in the T2DM group compared to the healthy controls. Furthermore, this reduction is more intense in the D3 group than in D2 and D1. Correspondingly, in frequency domain parameters: total power, high-frequency power, and low-frequency power were significantly reduced in all the T2DM groups compared to healthy controls. The study concludes that the overall HRV (as determined by total power), sympathetic activity (low frequency power) and parasympathetic activity (time domain measures and high frequency power) were significantly reduced in all the diabetic subgroups except prediabetes as compared to the healthy controls, implying that both sympathetic and parasympathetic limbs are symmetrically affected in T2DM patients even in the earliest stages (<5 yrs) implying subclinical cardiac autonomic dysfunction in the earliest stages.

Diabesity in Elderly Cardiovascular Disease Patients: Mechanisms and Regulators

Cardiovascular disease (CVD) is the leading cause of death in the world. In 2019, 550 million people were suffering from CVD and 18 million of them died as a result. Most of them had associated risk factors such as high fasting glucose, which caused 134 million deaths, and obesity, which accounted for 5.02 million deaths. Diabesity, a combination of type 2 diabetes and obesity, contributes to cardiac, metabolic, inflammation and neurohumoral changes that determine cardiac dysfunction (diabesity-related cardiomyopathy). Epicardial adipose tissue (EAT) is distributed around the myocardium, promoting myocardial inflammation and fibrosis, and is associated with an increased risk of heart failure, particularly with preserved systolic function, atrial fibrillation and coronary atherosclerosis. In fact, several hypoglycaemic drugs have demonstrated a volume reduction of EAT and effects on its metabolic and inflammation profile. However, it is necessary to improve knowledge of the diabesity pathophysiologic mechanisms involved in the development and progression of cardiovascular diseases for comprehensive patient management including drugs to optimize glucometabolic control. This review presents the mechanisms of diabesity associated with cardiovascular disease and their therapeutic implications.

Triglyceride glucose index is related with cardiac autonomic dysfunction in patients with metabolic syndrome

Aim    Cardiac autonomic dysfunction is encountered in approximately 25 % of patients with metabolic syndrome (MetS). 24 hr Holter-ECG based heart rate variability (HRV) and heart rate turbulence (HRT) parameters are used to evaluate cardiac autonomic function. We aimed to investigate the relationship between a novel insulin resistance marker, triglyceride glucose (TyG) index and cardiac autonomic dysfunction in patients with MetS.Material and methods    We examined a total of 400 non-diabetic subjects, 136 with MetS and 264 without MetS. All underwent TyG index calculations, and 24 hr Holter-ECG recordings for the measurement of HRV and HRT parameters.Results    HRV and HRT parameters were lower or higher in patients with MetS than in subjects without MetS, indicating cardiac autonomic dysfunction. We observed significant correlations between TyG index and measures of cardiac autonomic function. Multiple linear regression analysis showed that the TyG index was an independent predictor of almost all HRV and HRT parameters.Conclusion    This study demonstrates the independent relationship between cardiac autonomic dysfunction and the TyG index, a novel marker of insulin resistance in non-diabetic patients with MetS.

Fluoxetine Treatment Decreases Cardiac Vagal Input and Alters the Serotonergic Modulation of the Parasympathetic Outflow in Diabetic Rats

Comorbid diabetes and depression constitutes a major health problem, worsening associated cardiovascular diseases. Fluoxetine's (antidepressant) role on cardiac diabetic complications remains unknown. We determined whether fluoxetine modifies cardiac vagal input and its serotonergic modulation in male Wistar diabetic rats. Diabetes was induced by alloxan and maintained for 28 days. Fluoxetine was administered the last 14 days (10 mg/kg/day; p.o). Bradycardia was obtained by vagal stimulation (3, 6 and 9 Hz) or i.v. acetylcholine administrations (1, 5 and 10 μg/kg). Fluoxetine treatment diminished vagally-induced bradycardia. Administration of 5-HT originated a dual action on the bradycardia, augmenting it at low doses and diminishing it at high doses, reproduced by 5-CT (5-HT_1/7 agonist). 5-CT did not alter the bradycardia induced by exogenous acetylcholine. Decrease of the vagally-induced bradycardia evoked by high doses of 5-HT and 5-CT was reproduced by L-694,247 (5-HT_1D agonist) and blocked by prior administration of LY310762 (5-HT_1D antagonist). Enhancement of the electrical-induced bradycardia by 5-CT (10 μg/kg) was abolished by pretreatment with SB269970 (5-HT₇ receptor antagonist). Thus, oral fluoxetine treatment originates a decrease in cardiac cholinergic activity and changes 5-HT modulation of bradycardic responses in diabetes: prejunctional 5-HT₇ receptors augment cholinergic-evoked bradycardic responses, whereas prejunctional 5-HT_1D receptors inhibit vagally-induced bradycardia.

Naringin Relieves Diabetic Cardiac Autonomic Neuropathy Mediated by P2Y14 Receptor in Superior Cervical Ganglion

Diabetes mellitus (DM), an emerging chronic epidemic, contributes to mortality and morbidity around the world. Diabetic cardiac autonomic neuropathy (DCAN) is one of the most common complications associated with DM. Previous studies have shown that satellite glial cells (SGCs) in the superior cervical ganglia (SCG) play an indispensable role in DCAN progression. In addition, it has been shown that purinergic neurotransmitters, as well as metabotropic GPCRs, are involved in the pathophysiological process of DCAN. Furthermore, one traditional Chinese medicine, naringin may potently alleviate the effects of DCAN. Ferroptosis may be involved in DCAN progression. However, the role of naringin in DCAN as well as its detailed mechanism requires further investigation. In this research, we attempted to identify the effect and relevant mechanism of naringin in DCAN mitigation. We observed that compared with those of normal subjects, there were significantly elevated expression levels of P2Y₁₄ and IL-1β in diabetic rats, both of which were remarkably diminished by treatment with either P2Y₁₄ shRNA or naringin. In addition, abnormalities in blood pressure (BP), heart rate (HR), heart rate variability (HRV), sympathetic nerve discharge (SND), and cardiac structure in the diabetic model can also be partially returned to normal through the use of those treatments. Furthermore, a reduced expression of NRF2 and GPX4, as well as an elevated level of ROS, were detected in diabetic cases, which can also be improved with those treatments. Our results showed that naringin can effectively relieve DCAN mediated by the P2Y₁₄ receptor of SGCs in the SCG. Moreover, the NRF2/GPX4 pathway involved in ferroptosis may become one of the principal mechanisms participating in DCAN progression, which can be modulated by P2Y₁₄-targeted naringin and thus relieve DCAN. Hopefully, our research can supply one novel therapeutic target and provide a brilliant perspective for the treatment of DCAN.

Glycemic status, non-traditional risk and left ventricular structure and function in the Jackson Heart Study

BACKGROUND

Left ventricular structure and function abnormalities may be an early marker of cardiomyopathy among African Americans with diabetes (DM) even in the absence of coronary artery disease (CAD), arrhythmia, valvular heart disease and end-stage renal disease (ESRD). This study examined the association of prediabetes (PDM), DM and HbA1c with left ventricular structure and function among Jackson Heart Study (JHS) participants without traditional risk factors.

METHODS

Retrospective cross-sectional analyses of the association of PDM, DM and HbA1c with, left ventricular ejection fraction (LV EF), fractional shortening (LV FS), stroke volume index (SVI), cardiac index (CI), left ventricular end diastolic volume index (LVEDVI), left ventricular end systolic volume index (LVESVI), relative wall thickness (RWT), myocardial contraction fraction (MCF) and left ventricular mass index (LVMI). The study was conducted in 2234 adult JHS participants without preexisting CAD, arrhythmia, valvular heart disease or ESRD. Statistical analyses included descriptive, univariate and covariate adjusted linear regression analyses. Sensitivity analyses to explore the impact of hypertension on study outcomes were also carried out.

RESULTS

DM compared with no DM was associated with lower, SVI (- 0.96 ml/m2, p = 0.029), LVEDVI (- 1.44 ml/m2 p = 0.015), and MCF (- 1.90% p = 0.007) but higher CI (0.14 L/min/m2, p < 0.001), RWT (0.01 cm, p = 0.002) and LVMI (2.29 g/m2, p = 0.009). After further control for DM duration, only CI remaining significantly higher for DM compared with no DM participants (0.12 L/min/m2, p = 0.009). PDM compared with no PDM was associated with lower, SVI (- 0.87 ml/m2, P = 0.024), LVEDVI (- 1.15 ml/m2 p = 0.003) and LVESVI (- 0.62 ml/m2 p = 0.025). HbA1c ≥ 8.0% compared with HbA1c < 5.7% was associated with lower SVI (- 2.09 ml/m2, p = 0.004), LVEDVI (- 2.11 ml/m2 p = 0.032) and MCF (- 2.94% p = 0.011) but higher CI (0.11 L/min/m2, p = 0.043) and RWT (0.01 cm, p = 0.035).

CONCLUSIONS

Glycemic status is associated with important left ventricular structure and function changes among African Americans without prior CAD, arrhythmia, valvular heart disease and ESRD. Longitudinal studies may further elucidate these relationships.

Novel Application of Multiscale Cross-Approximate Entropy for Assessing Early Changes in the Complexity between Systolic Blood Pressure and ECG R-R Intervals in Diabetic Rats

Cardiac autonomic neuropathy (CAN) is a common complication of diabetes mellitus, and can be assessed using heart rate variability (HRV) and the correlations between systolic blood pressure (SBP) and ECG R-R intervals (RRIs), namely baroreflex sensitivity (BRS). In this study, we propose a novel parameter for the nonlinear association between SBP and RRIs based on multiscale cross-approximate entropy (MS-CXApEn). Sixteen male adult Wistar Kyoto rats were equally divided into two groups: streptozotocin-induced diabetes and age-matched controls. RRIs and SBP were acquired in control rats and the diabetic rats at the onset of hyperglycemia and insulin-treated euglycemia to determine HRV by the ratio of low-frequency to high-frequency power (LF/HF) and Poincaré plot as SSR (SD1/SD2), BRS, and MS-CXApEn. SSR and BRS were not significantly different among the three groups. The LF/HF was significantly higher in the hyperglycemic diabetics than those in the controls and euglycemic diabetic rats. MS-CXApEn was higher in the diabetic hyperglycemic rats than the control rats from scales 2 to 10, and approached the values of controls in diabetic euglycemic rats at scales 9 and 10. Conclusions: We propose MS-CXApEn as a novel parameter to quantify the dynamic nonlinear interactions between SBP and RRIs that reveals more apparent changes in early diabetic rats. Furthermore, changes in this parameter were related to correction of hyperglycemia and could be useful for detecting and assessing CAN in early diabetes.

Exosomal microRNAs: potential targets for the prevention and treatment of diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM), a condition in which myocardial dysfunction is caused by diabetes mellitus, has become an epidemic disorder in the world. DCM initially presents as diastolic relaxation dysfunction and will progress to heart failure in the absence of coronary artery disease, valvular disease, and other conventional cardiovascular risk factors such as hypertension and dyslipidemia. However, the underlying molecular mechanisms of DCM are poorly understood. Recent studies reveal that exosomal miRNAs are associated with multiple DCM risk factors and may act as potential therapeutic targets. Therefore, this review summarizes the recent advancements to understand the role of exosomal miRNAs in DCM development and explores potential preventative and therapeutic strategies.

Association Between Serum Albumin Levels and Diabetic Peripheral Neuropathy Among Patients with Type 2 Diabetes: Effect Modification of Body Mass Index

BACKGROUND

The role of serum albumin in the risk of diabetic peripheral neuropathy (DPN) remains unclear. This study aimed to explore the relationship between serum albumin level and DPN, and to examine any possible effect modifiers among patients with type 2 diabetes mellitus.

METHODS

This cross-sectional study was conducted in Jiangxi, China, from May 2012 to December 2014. Serum albumin levels were determined in 523 subjects, and the association between serum albumin level and DPN was evaluated using linear regression models (odds ratio [OR] and corresponding 95% confidence interval [CI]).

RESULTS

There was a significant inverse association between serum albumin level (per 1 g/L increment, OR 0.95 [95% CI 0.92-0.98]) and the risk of DPN. Accordingly, when serum albumin was assessed as quartiles, a significantly lower risk of DPN was found in participants in quartile 4 (OR 0.49 [95% CI 0.25-0.95]), compared with those in quartile 1. Consistently, higher albumin levels (≥35 g/L) were associated with decreased odds for DPN (OR 0.36 [95% CI 0.17-0.74]) compared with lower levels. Furthermore, the albumin-DPN association was significantly stronger in patients with a relatively high body mass index (BMI; ≥24 kg/m²; OR 0.91 [95% CI 0.85-0.98]) than in those with a low BMI (<24 kg/m²; OR 0.99 [95% CI 0.94-1.04]; P for interaction = 0.042).

CONCLUSION

These data suggest that serum albumin level could be a novel risk factor for DPN among patients with type 2 diabetes and relatively high BMI (>24 kg/m²).

Effect of alpha-lipoic acid on arterial stiffness parameters in type 2 diabetes mellitus patients with cardiac autonomic neuropathy

Objective. Significantly underdiagnosed, diabetes-associated cardiac autonomic neuropathy (CAN) causes a wide range of cardiac disorders that may cause life-threatening outcomes. This study investigated the effects of alpha-lipoic acid (ALA) on arterial stiffness and insulin resistance (IR) parameters in type 2 diabetes mellitus (T2D) patients and definite CAN. Methods. A total of 36 patients with T2D and a definite stage of CAN were recruited. This investigation was carried out on two separate arms: traditional hypoglycemic therapy (n=18, control) and ALA (n=18) 600 mg in film-coated tablets/q.d. in addition to traditional hypoglycemic therapy. The duration of the study was three months. Results. In subjects with T2D and definite stage of СAN, treatment with ALA resulted in a significant decrease of glucose, immunoreactive insulin concentration, and Homeostasis Model Assessment (HOMA)-IR (HOMA-IR) parameters; pulse wave velocity (PWV), aorta augmentation index (AIxao) during the active period of the day and decrease of PWV, AIxao, and brachial augmentation index during the passive period of the day compared with the results, obtained in the control group. Therefore, the administration of ALA to patients with T2D for three months promotes the improvement of glucose metabolism and arterial stiffness parameters. Conclusions. In patients with T2D and definite stage of СAN treatment with ALA improved HOMA-IR and arterial stiffness parameters. These findings can be of clinical significance for the complex treatment of diabetes-associated CAN.

Cardiac autonomic neuropathy and risk of cardiovascular disease and mortality in type 1 and type 2 diabetes: a meta-analysis

We aimed to determine the prognostic association between cardiac autonomic neuropathy (CAN) and cardiovascular disease events (CVE) and mortality in type 1 and type 2 diabetes through a systematic review and meta-analysis. This systematic review and meta-analysis was registered with PROSPERO (CRD42020216305) and was conducted with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodological criteria. CAN was defined on the basis of 1 (early/possible CAN) or ≥2 (definite CAN) positive autonomic function tests as per the Toronto Consensus guidelines. Studies included those with prospective CVE or mortality data. Methodological variables/risk of bias were assessed using ROBINS-I (Risk Of Bias In Non-randomized Studies - of Interventions) and RoB-2 (Risk-Of-Bias tool for randomized trials) appraisal tools. Electronic database searches yielded 18 467 articles; 84 articles were screened full-text, 26 articles fulfilled the inclusion criteria for quantitative synthesis. Sixteen studies from patients with (n=2875) and without (n=11 722) CAN demonstrated a pooled relative risk (RR) of 3.16 (95%CI 2.42 to 4.13; p<0.0001) of future CVE in favour of CAN. Nineteen studies provided all-cause mortality data from patients with (n=3679) and without (n=12 420) CAN, with a pooled RR of 3.17 (95%CI 2.11 to 4.78; p<0.0001) in favour of CAN. The risk of both future CVE and mortality was higher in type 1 compared with type 2 diabetes and with a definite CAN (vs possible CAN) diagnosis. Three studies were considered to have risk of serious bias. This study confirms the significant association between CAN and CVE and all-cause mortality. The implementation of population-based CAN screening will identify a subgroup with disproportionately higher cardiovascular and mortality risk that will allow for earlier targeted intervention.

Autonomic and Somatic Nerve Functions in Type 2 Diabetes Mellitus Patients: Electrophysiological Aspects

Objectives: To investigate the relationship between neurophysiological sensory and motor nerve function parameters, assessed by nerve conduction studies (NCS) with parasympathetic autonomic function and by heart rate variability (HRV) tests in patients with type 2 diabetes mellitus (T2DM). Material and Methods: A total of 161 T2DM patients underwent NCS. Cardiac autonomic response was assessed by HRV tests to deep breathing (HRV DB), to Valsalva manoeuvre, and during postural change from lying to standing. Results: The amplitude of motor response in the median nerve, tibial nerve, and peroneal nerve was associated with reduced HRV DB (p = 0.0001). The amplitude of motor response in the median nerve, tibial nerve, and peroneal nerve was associated with reduced HRV Valsalva (p = 0.0001). The correlation between the amplitude of response in all sensory nerves (sural, median, and ulnar) and HRV DB was statistically significant (p = 0.0001). Conclusion: The results indicate that there is a correlation in T2DM patients between the damage of small myelinated and unmyelinated nerve fibres from cardiac autonomic nerves, assessed by HRV tests and damage of large motor and sensory fibres, assessed by NCS. Based on the above results, a combination of NCS and HRV tests should be considered in the neurophysiological approach to diabetic neuropathy.

Leisure-Time Physical Activity and Glycemic Control Independently Predicts Cardiac Autonomic Neuropathy in Type 2 Diabetes Mellitus

BACKGROUND

Though cardiac autonomic neuropathy (CAN) is a common complication of type 2 diabetes mellitus (T2DM); still, there is lack of clarity on pathophysiological correlates for its onset and progression. Therefore, the purpose of this study was to investigate the predictive ability of lifestyle and cardiometabolic risk factors for CAN in T2DM patients.

METHODS

A total of 105 Indian T2DM patients were recruited in the present study. Cardiometabolic risk factors, such as glycemic control, lipids, resting heart rate, systolic and diastolic blood pressure, and lifestyle risk parameters, such as physical activity levels and sleep quality were assessed. Standard cardiovascular autonomic reflex tests were performed for diagnosing CAN by Ewing's criteria.

RESULTS

Leisure-time physical activity and glycosylated hemoglobin were significant independent predictors of CAN in T2DM. Leisure-time physical activity and glycosylated hemoglobin predicted the occurrence of CAN at cutoff values ≤4.68 metabolic equivalent-hours per week (P = .007) and >7.5% (P = .002), respectively.

CONCLUSIONS

The T2DM patients should be encouraged to engage in leisure-time physical activity of at least 4.68 metabolic equivalent-hours per week (equivalent to 1.2 h of walk or 0.6 h of jog per week) and therapeutic strategies for controlling hyperglycemia in T2DM should aim to reduce glycosylated hemoglobin below 7.5% to reduce CAN occurrence.