Effects of Multi-Electrode Renal Denervation on Insulin Sensitivity and Glucose Metabolism in a Canine Model of Type 2 Diabetes Mellitus

Cardiac sympathetic nerve activity trends after renal denervation in heart failure with preserved ejection fraction

This case report describes the application of ultrasound renal denervation (uRDN) using the Paradise System in a patient with heart failure with preserved ejection fraction. Initially, the cardiac sympathetic nerve activity of the patient exhibited a late heart/mediastinum (H/M) ratio of 2.00 and a washout rate of 66.0% by cardiac iodine-123 metaiodobenzylguanidine (123I-MIBG) scintigraphy. Subsequently, the patient underwent transfemoral uRDN targeting the left, right upper, and right lower renal arteries. At the 6 month follow-up, no significant change was observed in 123I-MIBG findings; however, the estimated stressed blood volume (eSBV) decreased from 1722 to 1029 mL/70 kg. At 18 months, 123I-MIBG findings improved, with the late H/M ratio reaching 2.76 and the washout rate decreasing to 43.1%. This case report highlights the potential of uRDN in reducing eSBV within 6 months and subsequently improving cardiac sympathetic nerve activity at the 18 month follow-up.

Unravelling the effect of renal denervation on glucose homeostasis: more questions than answers?

Renal Denervation (RDN) is an interventional, endovascular procedure used for the management of hypertension. The procedure itself aims to ablate the renal sympathetic nerves and to interrupt the renal sympathetic nervous system overactivation, thus decreasing blood pressure (BP) levels and total sympathetic drive in the body. Recent favorable evidence for RDN resulted in the procedure being included in the recent European Guidelines for the management of Hypertension, while RDN is considered the third pillar, along with pharmacotherapy, for managing hypertension. Sympathetic overactivation, however, is associated with numerous other pathologies, including diabetes, metabolic syndrome and glycemic control, which are linked to adverse cardiovascular health and outcomes. Therefore, RDN, via ameliorating sympathetic response, could be also proven beneficial for maintaining an euglycemic status in patients with cardiovascular disease, alongside its BP-lowering effects. Several studies have aimed, over the years, to provide evidence regarding the pathophysiological effects of RDN in glucose homeostasis as well as investigate the potential clinical benefits of the procedure in glucose and insulin homeostasis. The purpose of this review is, thus, to analyze the pathophysiological links between the autonomous nervous system and glycemic control, as well as provide an overview of the available preclinical and clinical data regarding the effect of RDN in glycemic control.

Possible organ-protective effects of renal denervation: insights from basic studies

Inappropriate sympathetic nervous activation is the body's response to biological stress and is thought to be involved in the development of various lifestyle-related diseases through an elevation in blood pressure. Experimental studies have shown that surgical renal denervation decreases blood pressure in hypertensive animals. Recently, minimally invasive catheter-based renal denervation has been clinically developed, which results in a reduction in blood pressure in patients with resistant hypertension. Accumulating evidence in basic studies has shown that renal denervation exerts beneficial effects on cardiovascular disease and chronic kidney disease. Interestingly, recent studies have also indicated that renal denervation improves glucose tolerance and inflammatory changes. In this review article, we summarize the evidence from animal studies to provide comprehensive insight into the organ-protective effects of renal denervation beyond changes in blood pressure.

The function of long non-coding RNA in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease is a disease that is currently prevalent in the world, increasingly becoming the mainstay of liver diseases. And its prevalence is rapidly increasing, but its pathogenesis is not entirely understood. Long non-coding RNAs have increasingly gained attention as science has progressed in recent years. Studies have shown that long non-coding RNAs are involved in a variety of biological processes in vivo, such as proliferation, differentiation, and apoptosis, and can affect disease by regulating gene expression. This review explores the biological processes involving long non-coding RNAs, including lipid metabolism, glucose metabolism, liver fibrosis, and apoptosis. In addition, we summarize how the different long non-coding RNAs involved in each process function. Finally, the shortcomings of long non-coding RNAs as potential therapeutic targets are briefly described. In conclusion, this article provides a clear visualization of the link that exists between long non-coding RNAs and non-alcoholic fatty liver disease.

Effectiveness of radiofrequency renal denervation in diseases with increased sympathetic nervous system activity

The article discusses the role of sympathetic nervous system hyperactivity in the pathogenesis of various pathologies (hypertension, heart failure, atrial fibrillation, metabolic syndrome, diabetes and systemic inflammatory response syndrome). On the example of large randomized clinical trials using catheter-based radiofrequency ablation, the antihypertensive effect in patients with uncontrolled hypertension has been proven. The first experimental and clinical studies on the effectiveness of renal denervation in reducing the activity of inflammatory markers, the incidence of atrial fibrillation and ventricular arrhythmia episodes, and improving the left ventricular contractility. The first clinical results of the favorable effect of renal denervation on carbohydrate metabolism (insulin resistance and glycemic level) in patients with metabolic syndrome and diabetes have been studied in detail.

Endovascular Celiac Denervation for Glycemic Control in Patients with Type 2 Diabetes Mellitus

PURPOSE

To investigate the safety and effects of catheter-based endovascular denervation (EDN) at the celiac artery, and the abdominal aorta around celiac artery on glycemic control in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

With a novel catheter system, EDN was conducted at the celiac artery along with the abdominal aorta around the celiac artery in patients with T2DM whose hemoglobin A1c (HbA1c) was >7.5%. The primary outcome was HbA1c at 6-month. Other outcomes included safety, oral glucose tolerant test (OGTT), homeostasis-model assessment of insulin resistance (HOMA-IR), fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG), and C-peptide test.

RESULTS

A total of 11 subjects were included for analysis. The technical success was 100% and no severe treatment-related adverse events or major complications were observed. Both HbA1c and HOMA-IR were significantly reduced at 6 months (9.9 vs. 8.0 %, P = 0.005; 13.3 vs. 6.0, P = 0.016). Decreases in FPG and 2hPG were observed (227.2 vs. 181.8 mg/dL, P < 0.001; 322.2 vs. 205.2 mg/dL, P = 0.001). C-peptide test indicated improved beta-cell function (area under curve [AUC] 0.23 vs. 0.28 pmol/mL, P =0.046). A reduction of daily insulin injection (P = 0.02) and improvement of liver function (alanine aminotransferase, P = 0.014; γ-glutamyl transpeptidase, P = 0.021) were also observed.

CONCLUSION

EDN at the celiac artery and the abdominal aorta around celiac artery elicited a clinically significant improvement in glycemic control and insulin resistance in patients with T2DM, with good tolerability as 6-month follow-up demonstrated.

Effects of catheter-based renal denervation on glycemic control and lipid levels: a systematic review and meta-analysis

AIMS

As an emerging interventional technique to treat resistant hypertension, renal denervation (RDN) has also attracted considerable attention due to its potential beneficial effects on glucose and lipid metabolism. Given that inconsistent results were documented among studies, we aimed to perform a systematic review and meta-analysis to elaborate on this issue.

METHODS

The PubMed, EMBASE, Web of Science (SCI) and ClinicalTrials.gov databases were comprehensively searched from their inception date to June 18, 2020, for relevant clinical studies evaluating the efficacy of RDN on glucose and lipid levels. The outcomes of interest were changes in fasting glucose, insulin, C-peptide, hemoglobin A1C (HbA1C), homeostatic model assessment-insulin resistance (HOMA-IR), cholesterol and triglyceride (TG) levels before versus after RDN and also RDN versus the control group. The mean differences (MDs) of the outcomes measured before versus after RDN and RDN versus the control group were pooled by a randomized effects model. Heterogeneity was quantified with Chi-square (χ²) and inconsistency index (I²). Assessment of publication bias was performed by the funnel plot and Egger's test.

RESULTS

A total of 1600 studies were initially identified. Nineteen of the identified studies (six randomized controlled studies, one non-randomized controlled studies and 12 observational cohort studies) involving 2245 subjects were included in the final analysis. No significant change was observed after RDN in fasting glucose (weighted mean difference [WMD]  - 0.19 mmol/L; 95% CI  - 0.37, 0.00 mmol/L), insulin (standardized mean difference [SMD]  - 0.01; 95% CI  - 0.41, 0.39), C-peptide (SMD  - 0.05; 95% CI  - 0.30, 0.21), HbA1C (SMD  - 0.05; 95% CI  - 0.17, 0.07), HOMA-IR (SMD  - 0.29; 95% CI  - 0.72, 0.14), total cholesterol (TC) (WMD  - 0.11 mmol/L; 95% CI  - 0.37, 0.15 mmol/L), and low-density lipoprotein cholesterol (LDL-C) levels (WMD  - 0.18 mmol/L; 95% CI  - 0.59, 0.24 mmol/L) during follow-up. Changes in fasting glucose, insulin, HbA1C and TC levels in RDN groups were not significantly different from those in the control group. High-density lipoprotein cholesterol (HDL-C) and TG were slightly improved after RDN (WMD 0.07 mmol/L, 95% CI 0.01, 0.14 mmol/L; WMD - 0.26 mmol/l, 95% CI  - 0.51,  - 0.01 mmol/L, respectively). The funnel plot and Egger's test demonstrated the absence of potential publication bias.

CONCLUSIONS

Catheter-based RDN appeared to have no impact on glucose metabolism. There was a statistically significant but clinically negligible improvement in HDL-C and TG levels based on the current evidence. Future research with more rigorous designs is warranted to draw definitive conclusions.

REGISTRATION DETAILS

The protocol of this meta-analysis was registered on PROSPERO (CRD42020192805). ( https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=192805 ).

A preliminary evaluation of the circulating leptin/adiponectin ratio in dogs with pituitary-dependent hyperadrenocorticism and concurrent diabetes mellitus

Leptin and adiponectin are thought to modulate insulin sensitivity and pancreatic β-cell function, but there is limited information regarding the adipokine status of hyperglycemic dogs with hyperadrenocorticism. This study aimed to determine whether alterations in the leptin/adiponectin ratio, insulin sensitivity, and/or pancreatic β-cell function are associated with diabetes mellitus (DM) in dogs with pituitary-dependent hyperadrenocorticism (PDH). A total of 48 client-owned dogs were included in this prospective observational study: 20 dogs with PDH (10 normoglycemic and 10 with DM), 15 dogs with DM, and 13 healthy dogs. The serum concentrations of leptin, adiponectin, resistin, interleukin (IL)-1β, IL-6, IL-10, IL-18, and tumor necrosis factor (TNF)-α were measured, and homeostatic model assessment indices (HOMAs) were calculated and compared among the groups. Serum leptin was significantly higher in PDH dogs with and without DM than in healthy and DM dogs, and it was lower in DM dogs than in PDH dogs without DM. Serum adiponectin was significantly lower in PDH dogs with DM than in healthy and PDH dogs, and it was significantly lower in DM dogs than in healthy dogs. Serum IL-10 was significantly higher in PDH dogs with DM than in healthy and PDH dogs without DM. The leptin/adiponectin ratio was significantly higher in PDH dogs with DM than in normoglycemic PDH dogs. Serum IL-6 concentrations were significantly higher in DM dogs than in healthy dogs. Serum IL-1β concentration was significantly higher in DM dogs than in healthy dogs and PDH dogs with DM and without DM. Serum TNF-α and IL-18 concentrations were not different among groups. The HOMA_{β-cell function} was significantly lower in PDH dogs with DM than in normoglycemic PDH dogs, while HOMA_{insulin sensitivity} was significantly lower in PDH dogs with DM than in healthy dogs. These results suggest that adipokine dysregulation, a reduction in insulin sensitivity, and a further impairment in pancreatic β-cell function might predispose PDH dogs to DM. Further longitudinal study will be necessary to confirm this result.

A Pilot Study of Perioperative External Circumferential Cryoablation of Human Renal Arteries for Sympathetic Denervation

Purpose

Cryoablation, which induces cellular death without extensive tissue damage, has been extensively used to denervate the myocardium. However, periadventitial external circumferential application of cryotherapy to denervate the renal artery sympathetic nerves has, to our knowledge, never been tested in humans. The main aim of this study was to examine the safety and potential effects of cryotherapy on ambulatory blood pressure levels and other outcomes that are indirectly related to sympathetic tone, including pulse-wave velocity, central pulse pressure, and glucose levels.

Materials and Methods

Five patients who underwent the denervation of the renal arteries during open surgery of the abdominal aortic aneurysm and four controls who did not undergo denervation during the surgery were enrolled. An argon-powered cryotherapy catheter (Cardioblate; Medtronic Inc., USA) was applied periadventitially to each renal artery in the five patients and then activated by infusion with liquid nitrogen for 1 minute.

Results

No cryoablation-related complications occurred in the five consecutive patients. Their ambulatory blood pressures 3 to 5 months after surgery did not demonstrate any general blood pressure-reducing effects, but two patients responded favorably with the reduction of antihypertensive medication and decreased 24-hour blood pressure. The patients’ mean HbA1C levels decreased from 5.9±0.78% to 5.6±0.71% (P=0.042).

Conclusion

This pilot study suggests that periadventitial cryoablation during open surgery can be used in the study of renal denervation in humans, as it had no complications in five patients in this study. The effectiveness of cryoablation for treating hypertension should be proven in a phase II clinical trial.

The potential role of lncRNAs in diabetes and diabetic microvascular complications

Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs that are longer than 200 nucleotides without protein-coding potential. Becasuse of which these RNAs have no significant protein-coding potential, they were initially considered as "junk-products" of transcription without biological meaning. Nevertheless, recent research advancements have shown that lncRNAs are involved in many physiological processes such as cell cycle regulation, cell apoptosis and survival, cancer migration and metabolism. This review described the function of lncRNAs and the potential underlying mechanism involved in diabetes and diabetic microvascular complications. The roles of lncRNAs in the pathogenesis of type 2 diabetes mellitus have only recently been recognized, involving hepatic glucose production and insulin resistance. We further investigated the mechanisms of lncRNAs in diabetic nephropathy (DN), including the roles of lncRNAs in mesangial cells (MCs) proliferation and fibrosis, inflammatory processes, extracellular matrix accumulation in the glomeruli and tubular injury. We also discussed the potential mechanism of lncRNAs in diabetic retinopathy (DR), including aberrant neovascularization and neuronal dysfunction. This review summarized the current knowledge of the functions and underlying mechanisms of lncRNAs in type 2 diabetes mellitus and related renal and retinal complications. Accumulating evidence suggests the potential of lncRNAs as therapeutic targets for clinical applications in the management of diabetes.

lncRNA MEG3 promotes hepatic insulin resistance by serving as a competing endogenous RNA of miR-214 to regulate ATF4 expression

MicroRNA (miR)-214 has been demonstrated to suppress gluconeogenesis by targeting activating transcription factor 4 (ATF4), which regulates gluconeogenesis by affecting the transcriptional activity of forkhead box protein O1 (FoxO1). Our previous study revealed that the upregulation of maternally expressed gene 3 (MEG3), a long noncoding RNA, enhanced hepatic insulin resistance via increased FoxO1 expression. The present study aimed to explore whether miR-214 and ATF4 were involved in the MEG3-mediated increase of FoxO1 expression. MEG3, miR-214 and ATF4 expression were examined by reverse transcription quantitative polymerase chain reaction and western blot analysis. The interaction among MEG3, miR-214 and ATF4 was analysed using the luciferase reporter assay. MEG3-targeting small interference RNAs were injected into high-fat diet (HFD)-fed mice to verify the role of MEG3 in hepatic insulin resistance in vivo. MEG-3 and ATF4 were demonstrated to be upregulated and miR-214 was indicated to be downregulated in the livers of HFD-fed and ob/ob mice. In mouse primary hepatocytes, palmitate time-dependently increased MEG3 and ATF4 but decreased miR-214 expression levels. Furthermore, MEG3 served as a competing endogenous RNA (ceRNA) for miR-214 to facilitate ATF4 expression, while miR-214 inhibition and ATF4 overexpression reversed the MEG3 knockdown-mediated decrease in the expression of FoxO1 and FoxO1-downstream targets phosphoenolpyruvate carboxykinase and glucose-6-phosphatase catalytic subunit. In HFD-fed mice, MEG3 knockdown substantially improved impaired glucose and insulin tolerance, while down-regulating HFD-induced ATF4 expression and upregulating HFD-suppressed miR-214 expression. In conclusion, MEG3 promoted hepatic insulin resistance by serving as a ceRNA of miR-214 to facilitate ATF4 expression. These data provide insight into the molecular mechanism of MEG3 involvement in the development of type 2 diabetes mellitus.