Dapagliflozin and measures of cardiovascular autonomic function in patients with type 2 diabetes (T2D)

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.

Dapagliflozin for Small Nerve Fibre Regeneration in Diabetic Peripheral Neuropathy: A Randomised Controlled Study (DINE)

OBJECTIVES

There are currently no FDA-approved disease-modifying therapies for diabetic peripheral neuropathy (DPN). We evaluated the effect of the sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin in Type 2 diabetes mellitus (T2DM) with DPN.

RESEARCH DESIGN AND METHODS

In this prospective, open-label, randomised, controlled study, 40 participants with DPN were randomised to receive add-on 10 mg dapagliflozin OD (Group A) to existing oral antidiabetic drugs (OAD) (n = 22) or continue OADs as a standard of care (Group B) (n = 18). Participants underwent assessment of neuropathic symptoms and signs (MNSI), vibration perception threshold (VPT), corneal confocal microscopy (CCM) to quantify corneal nerve fibre density (CNFD), corneal nerve branch density (CNBD) and corneal nerve fibre length (CNFL) and skin biopsy to assess intraepidermal nerve fibre density (IENFD) and plasma markers of oxidative stress at randomisation and after 6 months.

RESULTS

HbA1c decreased in Group A (p = 0.002) and Group B (p = 0.003), with no change in weight, body mass index (BMI) or lipids. Total MNSI increased in Group A (p = 0.01) with no change in Group B (p = 0.06). IENFD increased significantly in Group A (p = 0.01) and Group B (p = 0.01), while CNFD (p = 0.002), CNBD (p < 0.001) and CNFL (p = 0.025) increased in Group A with no change in Group B. There was a significant increase in glutathione peroxidase (p = 0.02) in Group A with no change in Group B, and a decrease in malondialdehyde in both groups (p < 0.001).

CONCLUSIONS

In participants with T2DM and DPN, dapagliflozin was associated with small nerve fibre regeneration and improvement in markers of oxidative stress.

TRIAL REGISTRATION

Clinical Trial Registry India, CRTI Reg. No (CTRI/2022/06/043236); ClinicalTrials.gov Identifier: NCT05162690.

Inflammatory Markers and Measures of Cardiovascular Autonomic Neuropathy in Type 1 Diabetes

BACKGROUND

Cardiovascular autonomic neuropathy (CAN) and inflammation predict more severe outcomes in type 1 diabetes (T1D). However, the link between CAN and inflammation in T1D remains unclear. We examined associations between CAN measures and inflammatory biomarkers in individuals with T1D.

METHODS AND RESULTS

In a cross-sectional study, we measured cardiovascular autonomic reflex tests and heart rate variability (established CAN measures) and a panel of 39 inflammatory biomarkers, including soluble urokinase plasminogen activator receptor (suPAR), in T1D participants of the TINSAL-T1DN (Targeting Inflammation with Salsalate in Individuals with T1D Neuropathy) trial (n=57, discovery), and the PERL (Preventing Early Renal Loss in Diabetes) trial (n=468, validation). Amongst 39 inflammatory biomarkers measured in TINSAL-T1DN, suPAR levels had the strongest negative correlations with CAN measures: expiration/inspiration (r=-0.48), Valsalva (r=-0.28), 30:15 (r=-0.37), SD of the normal RR interval (r=-0.37), and root mean square of differences of successive RR intervals (r=-0.31) (all P<0.05). Findings were validated in PERL. In unadjusted analyses, median suPAR levels significantly differed between the lowest and highest SD of the normal RR interval tertiles (3.79 versus 3.12 ng/mL, P<0.001) and root mean square of differences of successive RR intervals (3.76 versus 3.17 ng/mL, P<0.001). After adjusting for covariates (age, sex, hemoglobin A1c, and estimated glomerular filtration rate), median suPAR values remained significantly elevated in the lowest tertiles of SD of the normal RR interval (P=0.004) and root mean square of differences of successive RR intervals (P=0.006).

CONCLUSIONS

Amongst several inflammatory biomarkers, suPAR, an immune-mediated glycoprotein, has a singular association with CAN measures. The potential of targeting suPAR as a disease-modifying approach for CAN in T1D warrants further exploration.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT02936843, NCT02017171.

Modulating Sympathetic Nervous System With the Use of SGLT2 Inhibitors: Where There Is Smoke, There Is Fire?

Heart failure (HF) has become even more prevalent in recent years, because of improved diagnostics and an increase in the risk factors predisposing to its pathology. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) emerged as one of the key pharmacotherapy options for both reduced and preserved ejection fraction, providing cardio- and renoprotection and improving mortality and cardiovascular (CV) outcomes. The pleiotropism of SGLT2i has led to multiple efforts to understand their distinct pathophysiologic interactions with various pathways, including microcirculation, endothelial dysfunction, and inflammation. More recently, the role of SGLT2i on the sympathetic nervous system (SNS) is starting to be recognized, especially because observations of retained or reduced heart rate despite volume contraction have been noted by investigators in the large clinical trials testing the safety and efficacy of these agents. Both preclinical and clinical studies have been performed, with conflicting results. Interestingly, in both settings, although there are indications of SNS modulation by SGLT2i, other studies contradict such findings, without showing, however, worsening of the autonomic homeostasis. Given the importance of neuromodulation in HF, in both pharmacologic and interventional therapies, in this review, we aim to describe the role of SNS in CV disease, focusing on HF, analyze preclinical and clinical data regarding the efficacy of SGLT2i in modulating autonomic dysfunction by examining various markers of SNS activation, and provide the most plausible theoretical backgrounds on the mechanism of benefit of SNS from the inhibition of SGLT2 receptors.

Improvement of heart rate variability after metabolic bariatric surgery in Korean subjects with obesity

INTRODUCTION

Cardiovascular autonomic neuropathy (CAN) is a chronic complication of diabetes. As obesity is a major risk factor for CAN, we hypothesized that metabolic bariatric surgery (MBS) could improve CAN indices in Korean patients with obesity.

MATERIALS AND METHODS

Patients who underwent bariatric surgery between February 2020 and June 2022 were prospectively recruited. CAN was conducted once before surgery and again after surgery, using the Ewing method and heart rate variability (HRV) analysis (standard deviation of the NN interval [SDNN], root mean square of successive RR interval difference [RMSSD], and spectral analysis).

RESULTS

A total of 47 patients were included. The mean age was 39.8 ± 8.7 years, 15 (31.9%) were male, and 26 (55.3%) had diabetes. Resting HR before surgery was 81.0 ± 12.3 bpm, which decreased significantly to 68.0 ± 9.3 bpm after surgery (P < 0.001). Changes in HR and BP according to the Valsalva maneuver, postural changes, and handgrip were not significantly different before and after surgery. However, SDNN significantly increased from 25.2 [15.1, 33.5] to 38.0 [25.4, 45.0] ms (P < 0.001), and RMSSD also significantly increased from 17.0 [9.2, 31.8] to 28.2 [15.3, 45.6] ms (P = 0.001). Both low-frequency power (LF) and high-frequency power (HF) increased significantly, and the LF/HF ratio significantly decreased from 2.1 ± 1.6 to 1.3 ± 1.3 (P = 0.010). Loss of weight, fat mass, and lean body mass were independently associated with improving the HRV variables.

CONCLUSIONS

MBS improved HRV variables, and these changes were mainly associated with postoperative weight loss.

Effect of SGLT-2 inhibitors on cardiac autonomic function in type 2 diabetes mellitus: a meta-analysis of randomized controlled trials

BACKGROUND

Cardiac autonomic neuropathy (CAN) is a common complication of type 2 diabetes mellitus (T2DM). We sought to determine whether sodium-glucose co-transporter-2 (SGLT-2) inhibitors affect indices of CAN in patients with T2DM.

METHODS

We searched for parallel group or cross-over randomized controlled trials (RCTs) enrolling adult subjects with T2DM, assigned to a SGLT-2 inhibitor versus placebo or active comparator and addressing their effect on CAN. PubMed, Cochrane Library and gray literature sources were searched. We set as primary efficacy outcome the change in the low-frequency-to-high-frequency (LF/HF) ratio. We set as secondary efficacy outcomes: first, the change in the standard deviation of all 5 min mean normal RR intervals and second, the change in the square root of the mean of the sum of the squares of differences between adjacent RR intervals (r-MSSD). Protocol has not been registered at a publicly available repository.

RESULTS

We pooled data from four RCTs in a total of 247 subjects with T2DM. SGLT-2 inhibitor treatment did not have a significant effect on LF/HF ratio (MD = - 0.11, 95% CI - 0.35 to 0.12, I² = 0%, p = 0.36). SGLT-2 inhibitor treatment did not have a significant impact either on SDNN (MD = - 2.83, 95% CI - 7.41 to 1.75, I² = 31%, p = 0.23), or on r-MSSD (MD = - 0.14, 95% CI - 3.52 to 3.25, I² = 46%, p = 0.94). Overall risk of bias was graded as low across the selected RCTs.

CONCLUSION

SGLT-2 inhibitor treatment in patients with T2DM does not seem to provide any significant beneficial effect on CAN indices.

Pathophysiological and clinical aspects of the circadian rhythm of arterial stiffness in diabetes mellitus: A minireview

Several cross-sectional trials have revealed increased arterial stiffness connected with the cardiac autonomic neuropathy in types 2 and 1 diabetic patients. The pathophysiological relationship between arterial stiffness and autonomic dysfunction in diabetes mellitus is still underinvestigated and the question whether the presence of cardiac autonomic neuropathy leads to arterial stiffening or increased arterial stiffness induced autonomic nervous system impairment is still open. Both arterial stiffness and dysfunction of the autonomic nervous system have common pathogenetic pathways, counting state of the chronic hyperinsulinemia and hyperglycemia, increased formation of advanced glycation end products, activation of protein kinase C, development of endothelial dysfunction, and chronic low-grade inflammation. Baroreceptor dysfunction is thought to be one of the possible reasons for the arterial wall stiffening development and progression. On the contrary, violated autonomic nervous system function can affect the vascular tone and by this way alter the large arteries walls elastic properties. Another possible mechanism of attachment and/or development of arterial stiffness is the increased heart rate and autonomic dysfunction corresponding progression. This minireview analyzes the current state of the relationship between the diabetes mellitus and the arterial stiffness. Particular attention is paid to the analysis, interpretation, and application of the results obtained in patients with type 2 diabetes mellitus and diabetic cardiac autonomic neuropathy.