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

Diabetes alters cardiorespiratory dynamics: insights from short-term recurrence quantification analysis of pulse-respiration quotient

Introduction

The Pulse-Respiration Quotient (PRQ) is considered a powerful tool for assessing dynamic interactions between cardiac and respiratory rhythms. Type 2 diabetes mellitus (T2DM) disrupts autonomic control, potentially compromising the complexity and adaptability of cardiorespiratory dynamics. In this cross-sectional, exploratory study, we investigated whether T2DM alters cardiorespiratory dynamics by analyzing short-term PRQ signals using conventional linear indices and Recurrence Quantification Analysis (RQA).

Methods

Thirty-eight participants (20 T2DM and 18 controls) completed four standardized tasks-supine rest, orthostatic challenge, paced breathing, and the Valsalva maneuver-while electrocardiographic and respiratory signals were continuously recorded. From these signals, R-to-R peak interval (RRI) and breath-to-breath (BB) time series were derived, allowing us to compute the PRQ time series as the ratio of instantaneous heart rate to instantaneous breathing rate. Linear indices of PRQ and RQA metrics were then calculated for the PRQ signals, enabling comparisons between groups (T2DM vs. control) and across tasks. Additionally, entropy-based mutual information (MI) between RRI and BB was assessed as a quantitative measure of cardiorespiratory coupling.

Results

T2DM participants exhibited higher recurrence rates and prolonged recurrence time of the first type in the PRQ series, especially during paced breathing, suggesting a more rigid and less adaptive control mechanism. Although linear PRQ indices showed changes in some stage-dependent responses, they were less adept than RQA metrics at discerning subtle differences between groups. Furthermore, the complementary cardiorespiratory coupling assessment by MI revealed distinct compensatory patterns in T2DM during paced respiration and Valsalva.

Conclusion

These findings indicate potential dysautonomia or partial autonomic dysregulation in individuals with T2DM, as reflected by altered cardiorespiratory dynamics and reduced adaptability.

TCF7L2 as a target of peripheral artery disease in patients with type 2 diabetes: A 2-sample Mendelian randomization and bioinformatics study

This study examines the causal relationship between type 2 diabetes (T2D) and peripheral artery disease (PAD) and their potential mechanisms based on the analysis of the Gene Expression Omnibus database and 2-sample Mendelian randomization (MR). The first part involved a 2-sample MR study and a comprehensive meta-analysis. Differences in the results were assessed using inverse-variance weighting. Heterogeneity was examined using the Cochrane Q statistical test. The leave-one-out method was applied for sensitivity analysis. The potential horizontal pleiotropic effect was assessed using the MR-Egger intercept technique. The second part involved differential gene analysis and weighted gene coexpression network analysis. Subsequently, we overlapped and consolidated the results from the 2 parts to identify the key genes between them. MR analysis results suggested a statistically significant correlation between the incidence of PAD and T2D (odds ratio: 1.22, 95% confidence interval: 1.13-1.32, P = 3.74e-07). We anticipated a pivotal role for TCF7L2 in PAD and T2D. T2D was significantly associated with PAD risk. Simultaneously, the study deepened our understanding of the underlying mechanisms of both diseases, proposing TCF7L2 as a promising target.

Managing Type 2 Diabetes Mellitus via the Regulation of Gut Microbiota: A Chinese Medicine Perspective

BACKGROUND

Type 2 Diabetes Mellitus (T2DM) is a metabolic disorder characterized by insulin resistance and inadequate insulin production. Given the increased frequency of T2DM and the health issues it can cause, there is an increasing need to develop alternative T2DM management strategies. One such approach is Chinese Medicine (CM), a complementary therapy widely used in T2DM treatment. Given the emphasis on gut microbiota in current research, studying CM in the treatment of T2DM via gut microbiota modulation could be beneficial. Scope and approach: The use of various CM methods for managing T2DM via gut microbiota modulation is highlighted in this review. Following an introduction of the gut microbiota and its role in T2DM pathogenesis, we will review the potential interactions between gut microbiota and T2DM. Thereafter, we will review various CM treatment modalities that modulate gut microbiota and provide perspectives for future research. Key findings and discussion: In T2DM, Akkermansia, Bifidobacterium, and Firmicutes are examples of gut microbiota commonly imbalanced. Studies have shown that CM therapies can modulate gut microbiota, leading to beneficial effects such as reduced inflammation, improved metabolism, and improved immunity. Among these treatment modalities, Chinese Herbal Medicine and acupuncture are the most well-studied, and several in vivo studies have demonstrated their potential in managing T2DM by modulating gut microbiota. However, the underlying biomolecular mechanisms of actions are not well elucidated, which is a key area for future research. Future studies could also investigate alternate CM therapies such as moxibustion and CM exercises and conduct large-scale clinical trials to validate their effectiveness in treatment.

Evaluating Diagnostic Ultrasound of the Vagus Nerve as a Surrogate Marker for Autonomic Neuropathy in Diabetic Patients

Background and Objectives: Diagnostic ultrasound of the vagus nerve has been used to examine different polyneuropathies, and it has been suggested to be useful as a marker of autonomic dysfunction in diabetic patients. Materials and Methods: We analyzed the cross-sectional area (CSA) of the right vagus nerve of 111 patients with type 2 diabetes in comparison to 104 healthy adults and 41 patients with CIDP (chronic inflammatory demyelinating polyneuropathy). In the diabetes group, sympathetic skin response (SSR) was measured as an indicator for autonomic neuropathy. Carotid intima-media thickness (CIMT) was measured as a surrogate for atherosclerosis. Clinical symptoms of polyneuropathy were assessed using the Neuropathy Symptom Score and the Neuropathy Disability Score. Results: In total, 61.3% of the diabetes patients had clinical signs of polyneuropathy; 23.4% had no SSR at the feet as an indicator of autonomic neuropathy. Mean vagus nerve CSA did not differ in patients with and without diabetic polyneuropathy or in diabetic patients with and without SSR at the feet. No significant correlation was found between vagus nerve CSA and CIMT or SSR parameters in diabetic patients. Mean CSA of the right vagus nerve was slightly larger in diabetic patients (p = 0.028) and in patients with CIDP (p = 0.015) than in healthy controls. Conclusions: Effect sizes and mean differences were rather small so that a reliable diagnosis cannot be performed based on the vagus nerve measurement of a single person alone. Vagus nerve CSA seems not suitable as an indicator of autonomic dysfunction or cardiovascular risk in diabetic patients.

Research for correlation between heart rate variability parameters and bone mineral density in patients of type 2 diabetes mellitus

PURPOSE

The relationship of CAN and BMD, fracture risk is still unclear in T2DM. The aim of the present study is to investigate the correlation between heart rate variability (HRV) and BMD in T2DM.

METHODS

The study included 276 patients with T2DM aged ≥ 50 years, and Cardiovascular Autonomic Reflex Tests (CARTs) were applied to divide patients into two groups: CAN ( ±). 24 h Ambulatory ECG was assessed for HRV, BMD was measured by dual-energy X-ray bone densitometry, and FRAX scores were calculated for 10-year hip fracture risk (HF¹) and major osteoporotic fracture risk (MOF). Adjusted regression analysis was performed to investigate influence factors for BMD and fracture risk. ROC curve was used to analyze the optimal cut-off point of LF/HF for screening osteoporosis.

RESULTS

Baseline data showed significant differences in the duration of T2DM, insulin resistance index (HOMA-IR), 25-hydroxyvitamin D[25(OH)D], femoral neck BMD, hip BMD, lumbar BMD, HF¹, and MOF between the CAN ( +) and CAN (-) groups. The proportion of patients with osteoporosis increased as the degree of CAN lesion increased. Correlation analysis showed that LF/HF was significantly correlated with BMD, especially with hip (r = - 0.534, p < 0.001). Regression analysis showed that LF/HF was a risk factor for reduced BMD and increased fracture risk. The optimal cut-point value for LF/HF to predict osteoporosis by ROC curve analysis was 3.17.

CONCLUSIONS

CAN is associated with reduced BMD and increased fracture risk in patients with T2DM, and LF/HF may have the potential to be a predictor of diabetic osteoporosis and have some clinical value in early diagnosis of diabetic osteoporosis and non-traumatic fractures in T2DM.