Heparanase inhibition as a systemic approach to protect the endothelial glycocalyx and prevent microvascular complications in diabetes

BACKGROUND

Diabetes mellitus is a chronic disease which is detrimental to cardiovascular health, often leading to secondary microvascular complications, with huge global health implications. Therapeutic interventions that can be applied to multiple vascular beds are urgently needed. Diabetic retinopathy (DR) and diabetic kidney disease (DKD) are characterised by early microvascular permeability changes which, if left untreated, lead to visual impairment and renal failure, respectively. The heparan sulphate cleaving enzyme, heparanase, has previously been shown to contribute to diabetic microvascular complications, but the common underlying mechanism which results in microvascular dysfunction in conditions such as DR and DKD has not been determined.

METHODS

In this study, two mouse models of heparan sulphate depletion (enzymatic removal and genetic ablation by endothelial specific Exotosin-1 knock down) were utilized to investigate the impact of endothelial cell surface (i.e., endothelial glycocalyx) heparan sulphate loss on microvascular barrier function. Endothelial glycocalyx changes were measured using fluorescence microscopy or transmission electron microscopy. To measure the impact on barrier function, we used sodium fluorescein angiography in the eye and a glomerular albumin permeability assay in the kidney. A type 2 diabetic (T2D, db/db) mouse model was used to determine the therapeutic potential of preventing heparan sulphate damage using treatment with a novel heparanase inhibitor, OVZ/HS-1638. Endothelial glycocalyx changes were measured as above, and microvascular barrier function assessed by albumin extravasation in the eye and a glomerular permeability assay in the kidney.

RESULTS

In both models of heparan sulphate depletion, endothelial glycocalyx depth was reduced and retinal solute flux and glomerular albumin permeability was increased. T2D mice treated with OVZ/HS-1638 had improved endothelial glycocalyx measurements compared to vehicle treated T2D mice and were simultaneously protected from microvascular permeability changes associated with DR and DKD.

CONCLUSION

We demonstrate that endothelial glycocalyx heparan sulphate plays a common mechanistic role in microvascular barrier function in the eye and kidney. Protecting the endothelial glycocalyx damage in diabetes, using the novel heparanase inhibitor OVZ/HS-1638, effectively prevents microvascular permeability changes associated with DR and DKD, demonstrating a novel systemic approach to address diabetic microvascular complications.

The vascular complications of diabetes: a review of their management, pathogenesis, and prevention

INTRODUCTION

This review highlights the pathogenesis of both microvascular and macrovascular complications of diabetes and how these mechanisms influence both the management and preventative strategies of these complications. The cumulative data shown in this review suggest hyperglycemic and blood pressure control remain central to this intricate process.

AREAS COVERED

We reviewed the literature including retrospective, prospective trials as well as meta-analysis, and post hoc analysis of randomized trials on microvascular andmacrovascular complications.

EXPERT OPINION

Further research is needed to explore the ideal intervention targets and preventative strategies needed to prevent macrovascular complications. Furthermore, as the data for trials looking at microvascular complications lengthen more long-term data will further elucidate the role that the duration of diabetes has on these complications. Additionally, trials looking to maximize hyperglycemic control with multiple agents in diabetes, such as metformin, SGL2isand GLP-1 receptor agonists are currently in process, which will have implications for rates of microvascular as well as macrovascular complications.

Dysfunctional APPL1-Mediated Epigenetic Regulation in Diabetic Vascular Injury

BACKGROUND

APN (adiponectin) and APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) are potent vasculoprotective molecules, and their deficiency (eg, hypoadiponectinemia) contributes to diabetic vascular complications. However, the molecular mechanisms that govern their vasculoprotective genes as well as their alteration by diabetes remain unknown.

METHODS

Diabetic medium-cultured rat aortic endothelial cells, mouse aortic endothelial cells from high-fat-diet animals, and diabetic human aortic endothelial cells were used for molecular/cellular investigations. The in vivo concept-prove demonstration was conducted using diabetic vascular injury and diabetic hindlimb ischemia models.

RESULTS

In vivo animal experiments showed that APN replenishment caused APPL1 nuclear translocation, resulting in an interaction with HDAC (histone deacetylase) 2, which inhibited HDAC2 activity and increased H3Kac27 levels. Based on transcriptionome pathway-specific real-time polymerase chain reaction profiling and bioinformatics analysis, Angpt1 (angiopoietin 1), Ocln (occludin), and Cav1 (caveolin 1) were found to be the top 3 vasculoprotective genes suppressed by diabetes and rescued by APN in an APPL1-dependent manner. APN reverses diabetes-induced inhibition of Cav1 interaction with APPL1. APN-induced Cav1 expression was not affected by Angpt1 or Ocln deficiency, whereas APN-induced APPL1 nuclear translocation or upregulation of Angpt1/Ocln expression was abolished in the absence of Cav1 both in vivo and in vitro, suggesting Cav1 is upstream molecule of Angpt1/Ocln in response to APN administration. Chromatin immunoprecipitation-qPCR (quantitative polymerase chain reaction) demonstrated that APN caused significant enrichment of H3K27ac in Angpt1 and Ocln promoter region, an effect blocked by APPL1/Cav1 knockdown or HDAC2 overexpression. The protective effects of APN on the vascular system were attenuated by overexpression of HDAC2 and abolished by knocking out APPL1 or Cav1. The double knockdown of ANGPT1/OCLN blunted APN vascular protection both in vitro and in vivo. Furthermore, in diabetic human endothelial cells, HDAC2 activity is increased, H3 acetylation is decreased, and ANGPT1/OCLN expression is reduced, suggesting that the findings have important translational implications.

CONCLUSIONS

Hypoadiponectinemia and dysregulation of APPL1-mediated epigenetic regulation are novel mechanisms leading to diabetes-induced suppression of vasculoprotective gene expression. Diabetes-induced pathological vascular remodeling may be prevented by interventions promoting APPL1 nuclear translocation and inhibiting HDAC2.

A multi-centre investigation of macrovascular and non-ocular microvascular complications in children and adolescents with diabetes mellitus in southern Ghana

Objectives

To investigate the prevalence of macrovascular and non-ocular microvascular complications and the associated factors among children and adolescents with diabetes mellitus in selected hospitals in southern Ghana.

Design

A cross-sectional study.

Setting

The out-patient clinics of the Departments of Child Health, Medicine and Therapeutics, Family Medicine, Ophthalmology, and the National Diabetes Management and Research Centre, all at the Korle Bu Teaching Hospital, Accra, as well as from Cape-Coast Teaching Hospital in the Central Region of Ghana.

Participants

Fifty-eight children and adolescents aged 4-19 years who had been diagnosed with diabetes mellitus.

Main outcome measures

Macrovascular (peripheral artery disease and coronary heart disease) and non-ocular microvascular complications (neuropathy and nephropathy).

Results

Data from 58 children and adolescents with diabetes were analysed. The mean age of participants was 14.6±2.6 years, and a female preponderance was observed (45, 77.6%). The prevalence of macrovascular and non-ocular microvascular complications was 27.6% and 8.6%, respectively. Long duration of diabetes diagnosis (p=0.044) and low triglycerides (p=0.009) were associated with microvascular complications, while high triglycerides (p=0.032), lower HDL cholesterol (p=0.046), and abnormal body mass index (p=0.020) were associated with macrovascular complications.

Conclusions

Macrovascular and non-ocular microvascular complications are common among children and adolescents with diabetes in southern Ghana and are associated with a long duration of diabetes diagnosis, abnormal body mass index, low HDL cholesterol, and triglyceride levels. Therefore, the early institution of regular screening for diabetes-related complications to allow early detection and appropriate management is recommended.

Funding

University of Ghana Research Fund.

Diabetes Physical Examination

The physical examination of the patient with diabetes may have revealed findings that confirm the diagnosis, classify the type of diabetes, and begin to evaluate for the macro- and microvascular complications of diabetes and significant comorbid conditions. While screening for the diagnosis of diabetes occurs with assessment for abnormal blood glucose, given the high rates of morbidity and mortality associated with diabetes, utilization of the physical examination plays a key role in identifying patients at risk for the complications of diabetes. The discussion of elements of the physical examination relevant to the patient with diabetes, both type 1 and type 2, will be discussed in this article.

Cardiovascular Effects of Incretin-Based Therapies: Integrating Mechanisms With Cardiovascular Outcome Trials

As the worldwide prevalence of diabetes and obesity continues to rise, so does the risk of debilitating cardiovascular complications. Given the significant association between diabetes and cardiovascular risk, the actions of glucose-lowering therapies within the cardiovascular system must be clearly defined. Incretin hormones, including GLP-1 (glucagon-like peptide 1) and GIP (glucose-dependent insulinotropic polypeptide), are gut hormones secreted in response to nutrient intake that maintain glycemic control by regulating insulin and glucagon release. GLP-1 receptor agonists (GLP-1Ras) and dipeptidyl peptidase 4 inhibitors (DPP-4is) represent two drug classes used for the treatment of type 2 diabetes mellitus (T2DM) that improve glucose regulation through stimulating the actions of gut-derived incretin hormones or inhibiting their degradation, respectively. Despite both classes acting to potentiate the incretin response, the potential cardioprotective benefits afforded by GLP-1Ras have not been recapitulated in cardiovascular outcome trials (CVOTs) evaluating DPP-4is. This review provides insights through discussion of clinical and preclinical studies to illuminate the physiological mechanisms that may underlie and reconcile observations from GLP-1Ra and DPP-4i CVOTs. Furthermore, critical knowledge gaps and areas for further investigation will be emphasized to guide future studies and, ultimately, facilitate improved clinical management of cardiovascular disease in T2DM.

Endogenous Protective Factors and Potential Therapeutic Agents for Diabetes-Associated Atherosclerosis

The complications of macrovascular atherosclerosis are the leading cause of disability and mortality in patients with diabetes. It is generally believed that the pathogenesis of diabetic vascular complications is initiated by the imbalance between injury and endogenous protective factors. Multiple endogenous protective factors secreted by endothelium, liver, skeletal muscle and other tissues are recognized of their importance in combating injury factors and maintaining the homeostasis of vasculatures in diabetes. Among them, glucagon-like peptide-1 based drugs were clinically proven to be effective and recommended as the first-line medicine for the treatment of type 2 diabetic patients with high risks or established arteriosclerotic cardiovascular disease (CVD). Some molecules such as irisin and lipoxins have recently been perceived as new protective factors on diabetic atherosclerosis, while the protective role of HDL has been reinterpreted since the failure of several clinical trials to raise HDL therapy on cardiovascular events. The current review aims to summarize systemic endogenous protective factors for diabetes-associated atherosclerosis and discuss their mechanisms and potential therapeutic strategy or their analogues. In particular, we focus on the existing barriers or obstacles that need to be overcome in developing new therapeutic approaches for macrovascular complications of diabetes.

Protective effect of the curcumin-baicalein combination against macrovascular changes in diabetic angiopathy

Endothelial dysfunction is an early pathological event in diabetic angiopathy which is the most common complication of diabetes. This study aims to investigate individual and combined actions of Curcumin (Cur) and Baicalein (Bai) in protecting vascular function. The cellular protective effects of Cur, Bai and Cur+Bai (1:1, w/w) were tested in H₂O₂ (2.5 mM) impaired EA. hy926 cells. Wistar rats were treated with vehicle control as the control group, Goto-Kakizaki rats (n=5 each group) were treated with vehicle control (model group), Cur (150 mg/kg), Bai (150 mg/kg), or Cur+Bai (75 mg/kg Cur + 75 mg/kg Bai, OG) for 4 weeks after a four-week high-fat diet to investigate the changes on blood vessel against diabetic angiopathy. Our results showed that Cur+Bai synergistically restored the endothelial cell survival and exhibited greater effects on lowering the fasting blood glucose and blood lipids in rats comparing to individual compounds. Cur+Bai repaired the blood vessel structure in the aortic arch and mid thoracic aorta. The network pharmacology analysis showed that Nrf2 and MAPK/JNK kinase were highly relevant to the multi-targeted action of Cur+Bai which has been confirmed in the in vitro and in vivo studies. In conclusion, Cur+Bai demonstrated an enhanced activity in attenuating endothelial dysfunction against oxidative damage and effectively protected vascular function in diabetic angiopathy rats.

A Comprehensive Cardiovascular-Renal-Metabolic Risk Reduction Approach to Patients with Type 2 Diabetes Mellitus

Despite decades of research into risk-reduction strategies, cardiovascular disease and renal disease remain leading causes of morbidity and mortality among patients with type 2 diabetes mellitus. Given the tight clustering of cardiovascular and renal disease with the metabolic abnormalities of type 2 diabetes mellitus, we can think of these conditions together as cardiovascular-renal-metabolic disease states. A holistic view of cardiovascular-renal-metabolic disease states is critical to provide integrated patient-centered care to individuals with these disease states. Here, we explore the cardiovascular and renal risks associated with type 2 diabetes mellitus and highlight the importance of reducing cardiovascular-renal-metabolic disease risk in a comprehensive manner. We advocate a cross-disciplinary, team-based model to manage cardiovascular-renal-metabolic disease risk among patients with type 2 diabetes mellitus.

Optimal glycaemic and blood pressure but not lipid targets are related to a lower prevalence of diabetic microvascular complications

BACKGROUND

Diabetic microvascular complications are a major cause of morbidity and are related to glycaemic control and cardiovascular risk factors.

AIMS

We sought to determine the association of microvascular complications in relation to control of glycemia, blood pressure and lipids in T2DM patients attending secondary care in Qatar.

METHODS

This is a cross-sectional study undertaken in patients with T2DM attending Qatar's National Diabetes Centres. Patients underwent assessment of glycemia, blood pressure and lipids and prevalence of diabetic peripheral neuropathy (DPN), retinopathy and microalbuminuria.

RESULTS

We included 1114 subjects aged 52.1 ± 11.3 years with a duration of diabetes 10.0 ± 7.6 years and had a prevalence of 25.8% for DPN, 34.3% for painful DPN, 36.8% for microalbuminuria and 25.1% for retinopathy. Patients who achieved an HbA1c ≤ 7.0% compared to >7% had a significantly lower prevalence of DPN (P < 0.01), painful DPN (P < 0.01), retinopathy (P < 0.01) and microalbuminuria (P < 0.007). Patients who achieved a systolic BP ≤ 140 mmHg compared to >140 mmHg had a significantly lower prevalence of DPN (P < 0.001), painful DPN (P < 0.001), retinopathy (P < 0.001) and microalbuminuria (P < 0.001). Patients who achieved an LDL ≤2.6 mmol/l compared to >2.6 mmol/l had a significantly higher prevalence of DPN (P < 0.03), but no difference in other outcomes. There was no difference in microvascular complications between those who achieved a HDL-C ≥ 1.02 mmol/l, and among those who achieved triglycerides ≤1.7 mmol/l.

CONCLUSIONS

Optimal control of glycemia and blood pressure, but not lipids is associated with a lower prevalence of diabetic microvascular complications.

Improved Endothelium-Dependent Relaxation of Thoracic Aorta in Niclosamide-Treated Diabetic Rats

Diabetes-induced endothelial dysfunction is critical for the development of diabetic cardiovascular complications. The aim of this study was to investigate the effect of niclosamide (Nic) on vascular endothelial dysfunction in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were injected with a single intraperitoneal injection of STZ (75 mg/kg) to induce type 1 diabetes, and Nic (10 mg/kg) was intraperitoneally administered per day for 4 weeks. Endothelial function was evaluated as carbachol (CCh, an endothelium-dependent vasodilator)-evoked relaxation in the experiments performed on isolated thoracic aortas. The changes in the protein expressions of phosphorylated eNOS at serine 1177 (p-eNOSSer1177) and phosphorylated VASP at serine 239 (p-VASPSer239) of the rat aortas were analyzed by western blotting to determine whether NO/cGMP signaling is involved in the mechanism of Nic. STZ-injected rats had higher fasting blood glucose and less body weight compared to control rats (p < 0.05). Nic treatment did not affect blood glucose levels or body weights of the rats. CCh-induced endothelium-dependent relaxation of the aortic rings was significantly decreased in diabetic rats compared to control (Emax = 66.79 ± 7.41% and 90.28 ± 5.55%, respectively; p < 0.05). CCh-induced relaxation response was greater in Nic-treated diabetic rats compared to diabetic rats (Emax = 91.56 ± 1.20% and 66.79 ± 7.41%, respectively; p < 0.05). Phosphorylation of eNOS and VASP in aortic tissues was significantly reduced in diabetic rats, which were markedly increased by Nic treatment (p < 0.05). We demonstrated that Nic improved endothelial dysfunction possibly through the activation of NO/cGMP signaling without affecting hyperglycemia in diabetic rats. Our results suggesting that Nic has potential of repurposing for diabetic cardiovascular complications.

Fasting and fasting-mimicking treatment activate SIRT1/LXRα and alleviate diabetes-induced systemic and microvascular dysfunction

AIMS/HYPOTHESIS

Homo sapiens evolved under conditions of intermittent food availability and prolonged fasting between meals. Periods of fasting are important for recovery from meal-induced oxidative and metabolic stress, and tissue repair. Constant high energy-density food availability in present-day society contributes to the pathogenesis of chronic diseases, including diabetes and its complications, with intermittent fasting (IF) and energy restriction shown to improve metabolic health. We have previously demonstrated that IF prevents the development of diabetic retinopathy in a mouse model of type 2 diabetes (db/db); however the mechanisms of fasting-induced health benefits and fasting-induced risks for individuals with diabetes remain largely unknown. Sirtuin 1 (SIRT1), a nutrient-sensing deacetylase, is downregulated in diabetes. In this study, the effect of SIRT1 stimulation by IF, fasting-mimicking cell culture conditions (FMC) or pharmacological treatment using SRT1720 was evaluated on systemic and retinal metabolism, systemic and retinal inflammation and vascular and bone marrow damage.

METHODS

The effects of IF were modelled in vivo using db/db mice and in vitro using bovine retinal endothelial cells or rat retinal neuroglial/precursor R28 cell line serum starved for 24 h. mRNA expression was analysed by quantitative PCR (qPCR). SIRT1 activity was measured via histone deacetylase activity assay. NR1H3 (also known as liver X receptor alpha [LXRα]) acetylation was measured via western blot analysis.

RESULTS

IF increased Sirt1 mRNA expression in mouse liver and retina when compared with non-fasted animals. IF also increased SIRT1 activity eightfold in mouse retina while FMC increased SIRT1 activity and expression in retinal endothelial cells when compared with control. Sirt1 expression was also increased twofold in neuronal retina progenitor cells (R28) after FMC treatment. Moreover, FMC led to SIRT1-mediated LXRα deacetylation and subsequent 2.4-fold increase in activity, as measured by increased mRNA expression of the genes encoding ATP-binding cassette transporter (Abca1 and Abcg1). These changes were reduced when retinal endothelial cells expressing a constitutively acetylated LXRα mutant were tested. Increased SIRT1/LXR/ABC-mediated cholesterol export resulted in decreased retinal endothelial cell cholesterol levels. Direct activation of SIRT1 by SRT1720 in db/db mice led to a twofold reduction of diabetes-induced inflammation in the retina and improved diabetes-induced visual function impairment, as measured by electroretinogram and optokinetic response. In the bone marrow, there was prevention of diabetes-induced myeloidosis and decreased inflammatory cytokine expression.

CONCLUSIONS/INTERPRETATION

Taken together, activation of SIRT1 signalling by IF or through pharmacological activation represents an effective therapeutic strategy that provides a mechanistic link between the advantageous effects associated with fasting regimens and prevention of microvascular and bone marrow dysfunction in diabetes.

Effects of three types of bariatric interventions on myocardial infarct size and vascular function in rats with type 2 diabetes mellitus

AIMS

The effects of three types of bariatric interventions on myocardial infarct size were tested in the rat model of type 2 diabetes mellitus (T2DM). We also evaluated the effects of bariatric surgery on no-reflow phenomenon and vascular dysfunction caused by T2DM.

MAIN METHODS

Rats with T2DM were assigned into groups: without surgery, sham-operated, ileal transposition, Roux-en-Y gastric bypass, and sleeve gastrectomy. Oral glucose tolerance, glucagon-like peptide-1, and insulin levels were measured. Six weeks after surgery, the animals were subjected to myocardial ischemia-reperfusion followed by histochemical determination of infarct size (IS), no-reflow zone, and blood stasis area size. Vascular dysfunction was characterized using wire myography.

KEY FINDINGS

All bariatric surgery types caused significant reductions in animal body weight and resulted in T2DM compensation. All bariatric interventions partially normalized glucagon-like peptide-1 responses attenuated by T2DM. IS was significantly smaller in animals with T2DM. Bariatric surgery provided no additional IS limitation compared with T2DM alone. Bariatric surgeries reversed T2DM-induced enhanced contractile responses of the mesenteric artery to 5-hydroxytryptamine. Sleeve gastrectomy normalized decreased nitric oxide synthase contribution to the endothelium-dependent vasodilatation in T2DM.

SIGNIFICANCE

T2DM resulted in a reduction of infarct size and no-reflow zone size. Bariatric surgery provided no additional infarct-limiting effect, but it normalized T2DM-induced augmented vascular contractility and reversed decreased contribution of nitric oxide to endothelium-dependent vasodilatation typical of T2DM. All taken together, we suggest that this type of surgery may have a beneficial effect on T2DM-induced cardiovascular diseases.

Lactucaxanthin protects retinal pigment epithelium from hyperglycemia-regulated hypoxia/ER stress/VEGF pathway mediated angiogenesis in ARPE-19 cell and rat model

Hyperglycemia mediated perturbations in biochemical pathways induce angiogenesis in diabetic retinopathy (DR) pathogenesis. The present study aimed to investigate the protective effects of lactucaxanthin, a predominant lettuce carotenoid, on hyperglycemia-mediated activation of angiogenesis in vitro and in vivo diabetic model. ARPE-19 cells cultured in 30 mM glucose concentration were treated with lactucaxanthin (5 μM and 10 μM) for 48 h. They were assessed for antioxidant enzyme activity, mitochondrial membrane potential, reactive oxygen species, and cell migration. In the animal experiment, streptozotocin-induced diabetic male Wistar rats were gavaged with lactucaxanthin (200 μM) for 8 weeks. Parameters like animal weight gain, feed intake, water intake, urine output, and fasting blood glucose level were monitored. In both models, lutein-treated groups were considered as a positive control. Hyperglycemia-mediated angiogenic marker expressions in ARPE-19 and retina of diabetic rats were quantified through the western blot technique. Expression of hypoxia, endoplasmic reticulum stress markers, and vascular endothelial growth factor were found to be augmented in the hyperglycemia group compared to control (P < 0.05). Hyperglycemia plays a crucial role in increasing cellular migration and reactive oxygen species besides disrupting tight junction protein. Compared to lutein, lactucaxanthin aids retinal pigment epithelium (RPE) function from hyperglycemia-induced stress conditions via downregulating angiogenesis markers expression. Lactucaxanthin potentiality observed in protecting tight junction protein expression via modulating reactive oxygen species found to conserve RPE integrity. Results demonstrate that lactucaxanthin exhibits robust anti-angiogenic activity for the first time and, therefore, would be useful as an alternative therapy to prevent or delay DR progression.

Evaluation of irisin, retinol-binding protein 4, and leptin serum levels as biomarkers of macrovascular complications involvement in Saudi type 2 diabetes mellitus. A case-control study

Objectives:

To evaluate adipokine serum values of irisin, retinol-binding protein 4, and leptin in Saudi cases with type 2 diabetes mellitus (T2DM) for providing markers of T2DM macrovascular complications.

Methods:

This case-control research was carried out at Erfan Hospital, Jeddah, Saudi Arabia. The study included 138 subjects, classified into 3 groups: 46 T2DM patients with macrovascular complications, 46 T2DM without macrovascular complications, and 46 controls. Participants evaluated clinically and some biochemical parameters were measured.

Results:

Diabetic with and without macrovascular complications showed elevation of retinol-binding protein 4 (RBP4) and leptin; decreased irisin serum levels versus controls. Serum irisin was lower (p=0.007), while RBP4 was higher (p<0.0001) in T2DM patients with macrovascular complications versus without. Irisin showed negative correlations with fasting blood glucose (FBG), insulin, homeostatic model assessment of insulin resistance (HOMA-IR), RBP4, hemoglobin A1C (HbA1C), triglyceride, cholesterol, and low-density lipoprotein cholesterol. While RBP4 showed positive correlations with fasting blood glucose, insulin, HOMA-IR, leptin, and HbA1c; but a negative association with high-density lipoprotein cholesterol.

Conclusion:

Type 2 DM patients had raised RBP4 and leptin, but lower irisin levels versus controls. Irisin was lower, but RBP4 was higher in T2DM patients with macrovascular complications versus without, suggesting T2DM patients in pro-inflammatory conditions. These results suggested that irisin is protective, while RBP4 is a risk factor for T2DM macrovascular complications.

Microvascular Benefits of New Antidiabetic Agents: A Systematic Review and Network Meta-Analysis of Kidney Outcomes

CONTEXT

Diabetic kidney disease affects nearly one-third of US adults with prevalent type 2 diabetes mellitus (T2DM). The use of new antidiabetic medications in the prevention and treatment of diabetic kidney disease is a growing area of research interest.

OBJECTIVE

We sought to characterize the risk of developing a composite kidney outcome among patients receiving a new antidiabetic medication of the SGLT-2i, GLP-1ra, and DPP-4i drug classes.

METHODS

We conducted a systematic literature search in MEDLINE to identify randomized trials observing kidney safety endpoints associated with the use of new antidiabetic medications. Two independent reviewers selected the 7 eligible studies for analysis. Included studies were published between January 2013 and March 2020, conducted with adult participantss, published full-text in English, and observed composite kidney outcomes. A network meta-analysis was conducted within a Bayesian framework using a fixed-effects model with uninformative priors.

RESULTS

A qualitative assessment of transitivity was conducted to ensure similar distribution of potential modifiers across studies. Included studies were generally comparable in mean age, glycated hemoglobin A1c (HbA1c), and mean duration of T2DM at baseline.

MAIN CONCLUSIONS

Compared with placebo, dapagliflozin was associated with the greatest reduction in risk of developing the composite kidney outcome (hazard ratio 0.53; 95% credible interval, 0.43-0.66) followed by empagliflozin, canagliflozin, semaglutide, and liraglutide. Linagliptin did not show a significant reduction in risk of the outcome.

LIMITATIONS

This analysis was limited by the scarcity of data for kidney safety endpoints in large, randomized clinical trials. Although the heterogeneity statistic was low, there are slight differences in study design and baseline demographic characteristics across trials.

Fasting Glucose Variation Predicts Microvascular Risk in ACCORD and VADT

AIMS

The association of glycemic variability with microvascular disease complications in type 2 diabetes (T2D) has been under-studied and remains unclear. We investigated this relationship using both Action to Control Cardiovascular Risk in Diabetes (ACCORD) and the Veteran Affairs Diabetes Trial (VADT).

METHODS

In ACCORD, fasting plasma glucose (FPG) was measured 1 to 3 times/year for up to 84 months in 10 251 individuals. In the VADT, FPG was measured every 3 months for up to 87 months in 1791 individuals. Variability measures included coefficient of variation (CV) and average real variability (ARV) for fasting glucose. The primary composite outcome was time to either severe nephropathy or retinopathy event and secondary outcomes included each outcome individually. To assess the association, we considered variability measures as time-dependent covariates in Cox proportional hazard models. We conducted a meta-analysis across the 2 trials to estimate the risk of fasting glucose variability as well as to assess the heterogenous effects of FPG variability across treatment arms.

RESULTS

In both ACCORD and the VADT, the CV and ARV of FPG were associated with development of future microvascular outcomes even after adjusting for other risk factors, including measures of average glycemic control (ie, cumulative average of HbA1c). Meta-analyses of these 2 trials confirmed these findings and indicated FPG variation may be more harmful in those with less intensive glucose control.

CONCLUSIONS

This post hoc analysis indicates that variability of FPG plays a role in, and/or is an independent and readily available marker of, development of microvascular complications in T2D.

Treating latent autoimmune diabetes in adults in the era of cardiovascular outcomes trials: Old dog should learn new tricks

BACKGROUND

Latent autoimmune diabetes in adults (LADA) is characterised by pathophysiological and clinical heterogeneity. Hence, the optimal treatment strategy for this type of diabetes remains a clinical challenge.

AIM

To discuss the potential of a modern therapeutic approach for LADA in the context of the novel findings of cardiovascular outcomes trials and stress the controversies surrounding LADA and the barriers in the effective management of people with this type of diabetes.

METHODS

We performed a literature search in major biomedical databases in order to retrieve relevant literature. The results of key studies, along with the authors' clinical experience and perspective, are summarised and discussed in this narrative, mini review article.

RESULTS

Insulin remains the primary treatment choice in individuals with low C-peptide levels. Although cardiovascular outcomes trials have mainly recruited participants with type 2 diabetes, recent data suggest that the cardiorenal protective properties of the new therapies are even present in people without diabetes and thus, the extrapolation of their results on LADA individuals sounds reasonable. Therefore, sodium-glucose co-transporter 2 inhibitors (SGLT2is) and glucagon-like peptide-1 receptor agonists should be considered for the management of people with preserved insulin production being at high cardiovascular risk. The risk of diabetic ketoacidosis with SGLT2is requires increased vigilance by treating physicians.

CONCLUSIONS

Individualisation, preservation of beta-cell mass and function and cardiorenal protection are the new challenges in LADA therapy.

SGLT2 inhibitors and GLP1 agonists administered without metformin compared to other glucose-lowering drugs in patients with type 2 diabetes mellitus to prevent cardiovascular events: A systematic review

OBJECTIVES

To assess the efficacy of glucagon-like peptide-1 receptor agonists (GLP1-RAs) and sodium-glucose co-transporter 2 (SGLT2) inhibitors, administered without metformin on cardiovascular outcomes in type 2 diabetes patients.

METHODS

A systematic review was performed according to Cochrane's methodological standards. We included randomized clinical trials (RCTs) on adult type 2 diabetes patients, assessing the efficacy of SGLT2 inhibitors and GLP1-RAs compared to other glucose-lowering drugs and/or RCTs that presented data of a subgroup of type 2 diabetes patients without metformin use at baseline. The main outcome was the reduction of the risk of any major adverse cardiovascular events (MACE) reported individually or as a composite outcome.

RESULTS

Five RCTs including 50,725 type 2 diabetes patients, of whom 10,013 had not received metformin, were included in this meta-analysis. Three of these studies assessed the efficacy of GLP1-RAs and two of SGLT2 inhibitors. In patients without metformin at baseline, GLP1-RAs in comparison with placebo reduced the risk of MACE significantly by 20% (HR: 0.80; 95% CI: 0.71-0.89). SGLT2 inhibitors also significantly reduced the risk of MACE by 32% (HR: 0.68; 95% CI: 0.57-0.81).

CONCLUSIONS

SGLT2 inhibitors and GLP1-RAs provided without metformin at baseline may reduce the risk of MACE in comparison with placebo in type 2 diabetes patients at increased risk of cardiovascular events.

Benefits and Risks Associated With Aspirin Use in Patients With Diabetes for the Primary Prevention of Cardiovascular Events and Mortality: A Meta-Analysis

PURPOSE

A meta-analysis was conducted to assess the benefits and risks of aspirin for the primary prevention of cardiovascular disease and all-cause mortality events in adults with diabetes.

METHODS

An extensive and systematic search was conducted in MEDLINE (via PubMed), Cinahl (via Ebsco), Scopus, and Web of Sciences from 1988 to December 2020. A detailed literature search was conducted using aspirin, cardiovascular disease (CVD), diabetes, and efficacy to identify trials of patients with diabetes who received aspirin for primary prevention of CVD. Demographic details with the primary outcome of events and bleeding outcomes were analyzed. The Cochrane Collaboration's risk of bias tool was used to assess the methodological quality of the included studies. Random-effects meta-analysis was used to calculate the pooled odds ratio for outcomes of cardiovascular events, death, and adverse events.

FINDINGS

A total of 8 studies were included with 32,024 patients with diabetes; 16,001 allocated to aspirin, and 16,023 allocated to the control group. There was no difference between aspirin and control groups with respect to all-cause mortality, cardiovascular mortality, or bleeding events. However, MACE was significantly lower in the aspirin group.

IMPLICATIONS

Although aspirin has no significant risk on primary endpoints of cardiovascular events and bleeding outcomes in patients with diabetes compared to control, major adverse cardiovascular events (MACE) were significantly lower in the aspirin group. Further research on the use of aspirin alone or in combination with other antiplatelet drugs is required in patients with diabetes to supplement currently available research.

SYSTEMATIC REVIEW REGISTRATION

identifier [XU#/IRB/2020/1005].

Macrovascular Protecting Effects of Berberine through Anti-inflammation and Intervention of BKCa in Type 2 Diabetes Mellitus Rats

OBJECTIVE

The aim of this study was to examine the effect of berberine on diabetes mellitus in vivo and in vitro, and elucidate the underlying mechanisms.

METHODS

Rat models of type 2 diabetes mellitus (T2DM) were established and were treated with berberine. Pathological changes in the thoracic aorta, and inflammatory factor and adiponectin levels were investigated. Vascular smooth muscle cells (VSMCs) of the thoracic aorta were cultured and treated with berberine. Cellular proliferation, migration, and inflammatory factor levels were investigated. Responses of vascular rings to phenylephrine (PE) and sodium nitroprusside (SNP) after berberine intervention and the changes of relaxation responses to SNP after adding Iberiotoxin (IbTX) were investigated.

RESULTS

Berberine ameliorated the pathological status of the thoracic aorta in the T2DM rats. Berberine significantly inhibited the C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) production, and increased the adiponectin level compared with the model group. Compared with the model group, berberine inhibited the proliferation and migration of VSMCs in vitro, and reduced tumor growth factor-β1 (TGF-β1), IL-6, and TNF-α levels. Furthermore, the contraction of thoracic aorta to PE was reduced, while the relaxation response of thoracic aorta to SNP was increased, after the berberine intervention in the T2DM rats. The relaxation response of thoracic aorta to SNP in the model and berberine groups decreased after the IbTX treatment.

CONCLUSION

Protective effects of berberine against macrovascular complications induced by diabetes mellitus may be attributed to inhibiting of the inflammation and intervening of the calcium- activated potassium (BKCa).

The Protective Effect of Metformin on Abdominal Aortic Aneurysm: A Systematic Review and Meta-Analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) patients have a lower risk of abdominal aortic aneurysm (AAA) and its comorbidities, which might be associated with the usage of metformin. The objective of the study was to evaluate the role of metformin in the process of AAA development.

METHOD

PubMed, Embase and Cochrane Library were searched up to May 15^th, 2021. We implemented several methods including the risk of bias graph, GRADE system and funnel plot to assess the quality and possible bias of this study. Subgroup analysis and sensitivity analysis were applied to address quality differences and validate the robustness of the final results.

RESULT

Ten articles were enrolled after screening 151 articles searched from databases. The pooled results showed that, compared with T2DM patients without metformin, metformin prescription was associated with a slower annual growth rate of the aneurysm (mean difference (MD) -0.67 cm [95% confidence interval (CI) -1.20 ~ -0.15 cm]). Besides, metformin exposure was associated with a lower frequency of AAA events (odds ratio (OR) 0.61 [95% CI 0.41-0.92]).

CONCLUSION

Metformin alleviated both annual expansion rate and aneurysm rupture frequency in AAA patients with T2DM.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, identifier https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=217859 (CRD42020217859).

Exogenous sodium hydrosulfide protects against high glucose‑induced injury and inflammation in human umbilical vein endothelial cells by inhibiting necroptosis via the p38 MAPK signaling pathway

In recent years hydrogen sulfide (H2S) has demonstrated vasculoprotective effects against cell death, which suggests its promising therapeutic potential for numerous types of disease. Additionally, a protective effect of exogenous H2S in HG‑induced injuries in HUVECs was demonstrated, suggesting a potential protective effect for diabetic vascular complications. The present study aimed to investigate the mechanism accounting for the cytoprotective role of exogenous H2S against high glucose [HG (40 mM glucose)]‑induced injury and inflammation in human umbilical vein endothelial cells (HUVECs). HUVECs were exposed to HG for 24 h to establish an in vitro model of HG‑induced cytotoxicity. The cells were pretreated with sodium hydrosulfide (NaHS), a donor of H2S, or inhibitors of necroptosis and p38 MAPK prior to the exposure to HG. Cell viability, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), IL‑1β, IL‑6, IL‑8, TNF‑α, phosphorylated‑(p)38 and receptor‑interacting protein 3 (RIP3) expression levels were detected using the indicated methods, including Cell Counting Kit 8, fluorescence detection, western blotting, immunofluorescence assay and ELISAs. The results demonstrated that necroptosis and the p38 MAPK signaling pathway mediated HG‑induced injury and inflammation. Notably, NaHS was discovered to significantly ameliorate p38 MAPK/necroptosis‑mediated injury and inflammation in response to HG, as evidenced by an increase in cell viability, a decrease in ROS generation and loss of MMP, as well as the reduction in the secretion of proinflammatory cytokines. In addition, the upregulated expression of RIP3 induced by HG was repressed by treatment with SB203580, while the HG‑induced upregulation of p‑p38 expression levels were significantly downregulated following the treatment of Nec‑1 and RIP3‑siRNA. In conclusion, the findings of the present study indicated that NaHS may protect HUVECs against HG‑induced injury and inflammation by inhibiting necroptosis via the p38 MAPK signaling pathway, which may represent a promising drug for the therapy of diabetic vascular complications.

Roles and Mechanisms of Dipeptidyl Peptidase 4 Inhibitors in Vascular Aging

Vascular aging is characterized by alterations in the constitutive properties and biological functions of the blood vessel wall. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are indispensability elements in the inner layer and the medial layer of the blood vessel wall, respectively. Dipeptidyl peptidase-4 (DPP4) inhibitors, as a hypoglycemic agent, play a protective role in reversing vascular aging regardless of their effects in meliorating glycemic control in humans and animal models of type 2 diabetes mellitus (T2DM) through complex cellular mechanisms, including improving EC dysfunction, promoting EC proliferation and migration, alleviating EC senescence, obstructing EC apoptosis, suppressing the proliferation and migration of VSMCs, increasing circulating endothelial progenitor cell (EPC) levels, and preventing the infiltration of mononuclear macrophages. All of these showed that DPP4 inhibitors may exert a positive effect against vascular aging, thereby preventing vascular aging-related diseases. In the current review, we will summarize the cellular mechanism of DPP4 inhibitors regulating vascular aging; moreover, we also intend to compile the roles and the promising therapeutic application of DPP4 inhibitors in vascular aging-related diseases.

Targets for blood glucose: What have the trials told us

The challenges of diabetes treatment are to prevent or delay microangiopathic complications and macrovascular disease. Early, effective and sustained glycaemic control is advocated by all diabetes guidelines to mitigate the risks of prolonged hyperglycaemia. The post-hoc analyses of the large randomised glucose intervention trials and the long-term results of these trials have shown clearly that intensive glycaemic control may have more favourable cardiovascular effects when initiated earlier in the course of diabetes, particularly among in patients without cardiovascular disease. Based on the intervention trials a haemoglobin A1c level of less than 7.0% (<53 mmol/mol) is a generally accepted target to reduce microvascular disease and should be initiated early in the course of the diabetes. However, haemoglobin A1c targets should be individualised. Achieving a good glycaemic control without detrimental effect and preferably with benefit to the cardiovascular system and to renal function is an important challenge. When targeting a tight glycaemic control, avoidance of hypoglycaemia is crucial particularly in patients with coronary artery disease and in patients with heart failure. The cardiovascular outcomes trials performed to test the cardiovascular safety of the new glucose-lowering therapies offer compelling evidence in favour of the role of these drugs for cardiovascular prevention. Thus, both the glycaemic target and the choice of therapies should now be defined on an individual basis.

Lipid management for cardiovascular risk reduction in type 1 diabetes

PURPOSE OF REVIEW

To review the recent evidence for lipid management in type 1 diabetes (T1D) for cardiovascular risk reduction.

RECENT FINDINGS

Individuals with T1D are at increased risk for cardiovascular morbidity and mortality, with atherosclerosis beginning as early as adolescence. Elevated low-density lipoprotein cholesterol (LDL-C), triglycerides, and lipoprotein (a) are associated with increased cardiovascular risk in T1D. Although high-density lipoprotein cholesterol (HDL-C) in T1D is often normal or higher than in nondiabetic controls, HDL in T1D has structural alterations, which make it proatherogenic rather than cardioprotective. Similarly, although LDL-C is not particularly elevated in T1D, LDL still contributes to cardiovascular risk. Studies in individuals with diabetes have primarily included T2D participants, with a much smaller number of T1D participants; such studies have shown that lipid-lowering therapies, such as statins, ezetimibe, and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors reduce LDL-C levels and cardiovascular events in both those with and without diabetes. Individuals with T1D have increased cholesterol absorption, suggesting that ezetimibe may be particularly effective in T1D. Results of the REDUCE-IT trial show cardiovascular risk reduction from high-dose omega-3 fatty acid (Icosapent Ethyl) therapy in patients with diabetes (primarily type 2 diabetes), independent of triglyceride lowering, but similar data in T1D are currently lacking.

SUMMARY

Individuals with T1D are at high risk of cardiovascular disease, necessitating close lipid monitoring and management from adolescence through adulthood.

Cinnamaldehyde Ameliorates Vascular Dysfunction in Diabetic Mice by Activating Nrf2

BACKGROUND

Oxidative stress is known to be associated with the development of diabetes. Cinnamaldehyde (CA) is a spice compound in cinnamon that enhances the antioxidant defense against reactive oxygen species (ROS) by activating nuclear factor erythroid-related factor 2 (Nrf2), which has been shown to have a cardioprotection effect. However, the relationship between CA and Nrf2 in diabetic vascular complications remains unclear.

METHODS

Leptin receptor-deficient (db/db) mice were fed normal chow or diet containing 0.02% CA for 12 weeks. The vascular tone, blood pressure, superoxide level, nitric oxide (NO) production, renal morphology, and function were measured in each group.

RESULTS

CA remarkably inhibited ROS generation, preserved NO production, increased phosphorylated endothelial nitric oxide synthase (p-eNOS), attenuated the upregulation of nitrotyrosine, P22 and P47 in aortas of db/db mice, and apparently ameliorated the elevation of type IV collagen, TGF-β1, P22, and P47 in kidney of db/db mice. Feeding with CA improved endothelium-dependent relaxation of aortas and mesenteric arteries, and alleviated the remodeling of mesenteric arteries in db/db mice. Additionally, dietary CA ameliorated glomerular fibrosis and renal dysfunction in diabetic mice. Nrf2 and its targeted genes heme oxygenase-1 (HO-1) and quinone oxidoreductase-1 (NQO-1) were slightly increased in db/db mice and further upregulated by CA. However, these protective effects of CA were reversed in Nrf2 downregulation mice.

CONCLUSIONS

A prolonged diet of CA protects against diabetic vascular dysfunction by inhibiting oxidative stress through activating of Nrf2 signaling pathway in db/db mice.

Loss of association between HbA1c and vascular disease in older adults with type 1 diabetes

Aims

Robust evidence supports intensive glucose control in those with recently diagnosed type 1 diabetes to reduce the risk of developing micro- and macrovascular complications. Data to support longitudinal glycaemic targets is lacking. We aimed to explore if longer duration of diabetes and greater age might reduce the impact of glycaemia on the risk of vascular complications.

Research and design methods

Data for adults age 20 years or more, was extracted from a clinical database of people with type 1 diabetes cared for at a London teaching hospital. The presence or absence of micro- and macro-vascular complications was recorded. Multivariable logistic regression analysis was performed using HbA1c as independent variable, diabetes duration and age as continuous variable and obesity, hypertension, hypercholesterolaemia, low HDL cholesterol and hypertriglyceridaemia as categorical variables.

Results

Data from 495 patients was used. HbA1c above 60 mmol/mol (7.6%) was associated with increased microvascular complications in patients aged 20–44 years, independent of age and duration of diabetes. In older people with T1DM duration of diabetes was the major risk factor.

Conclusions

Our study suggests that increased age and greater duration of diabetes reduce the impact of glycaemia on the risk of vascular complications. Intensive blood glucose management in patients aged ≥45 years may have limited benefits in terms of reducing the risk of complications although this does not dismiss the benefits of good glycaemic control in older people with T1DM.

Pioglitazone for the Primary and Secondary Prevention of Cardiovascular and Renal Outcomes in Patients with or at High Risk of Type 2 Diabetes Mellitus: A Meta-Analysis

CONTEXT

The goal of the meta-analysis was to evaluate the effect of pioglitazone on the primary and secondary prevention of cardiovascular diseases (CVDs) and renal adverse events in patients with or at high risk of type 2 diabetes mellitus (T2DM).

DESIGN

Randomized controlled trials (RCTs) comparing pioglitazone with any control were identified through PubMed, Embase, and the Cochrane Library. Cardiovascular outcomes included major adverse cardiovascular events (MACEs, defined as the composite of nonfatal myocardial infarction, nonfatal stroke, and cardiovascular death), hospitalization for heart failure, and all-cause mortality. Renal outcomes included change in urinary albumin to creatinine ratio and 24-hour urinary protein excretion. Weighted mean difference (WMD) and risk ratio (RR) with 95% confidence intervals (CIs) were pooled.

RESULTS

A total of 26 studies with 19 645 participants were enrolled. Pioglitazone reduced the risk of MACE (RR, 0.8 [95% CI, 0.7-0.9]), with benefit only seen in patients with a history of established CVDs (0.8 [0.7-0.9]) and not in those without (1.0 [0.7-1.3]). Regarding the individual components, pioglitazone reduced the risk of nonfatal myocardial infarction (0.8 [0.6-1.0]) and nonfatal stroke (0.8 [0.7-0.9]), which was confined to patients with a history of established CVDs, whereas no treatment effect was found on cardiovascular death (1.0 [0.7-1.2]) regardless of the presence of established CVDs. Pioglitazone increased the risk of hospitalization for heart failure (1.3 [1.1-1.6]) and had no treatment effect on all-cause mortality (1.0 [0.8-1.1]). Pioglitazone reduced albuminuria by 18.5% (WMD 18.5% [95% CI, 21.1-16.0]), with a similar benefit in patients with different renal function categories.

CONCLUSIONS

Pioglitazone should be considered in patients with or at high risk of T2DM for the prevention of cardiovascular endpoints, especially in those with a history of established CVD who might benefit the most. Robust reductions in progression of renal disease are seen regardless of baseline renal function degree.

The emerging role of dyslipidemia in diabetic microvascular complications

PURPOSE OF REVIEW

To summarize recent advancements in our understanding of the impact of dyslipidemia on microvascular complications in type 2 diabetes (T2D), with an emphasis on peripheral neuropathy and nephropathy.

RECENT FINDINGS

Mounting evidence suggests that rigorous glycemic control only mitigates certain microvascular complications in T2D patients. Particularly, well regulated blood glucose levels only marginally improve peripheral neuropathy in the T2D setting. Dyslipidemia, an abnormal lipid profile, is emerging as a key factor in peripheral neuropathy. Furthermore, although glycemic control may prevent or slow nephropathy, recent developments demonstrate that dyslipidemia can also affect kidney outcomes in normoglycemic patients. Transcriptomic, epigenomic, and lipidomic investigations, as well as integrative approaches, are shedding light on potential pathomechanisms. These molecular studies are identifying possible targets for therapeutic intervention. Complementing molecular research, lifestyle interventions are on-going to assess whether dietary choices and/or exercise, weight-loss, or surgical interventions, such as bariatric surgery, can ameliorate peripheral neuropathy and nephropathy in T2D patients.

SUMMARY

Dyslipidemia is an emerging mechanism in microvascular complications in T2D. Elucidating the molecular pathomechanisms may pinpoint potential lipid-centric treatments. Interventional studies of dietary changes, exercise, or weight-loss surgery may also positively impact these highly prevalent and morbid complications.

Vascular improvements in individuals with type 2 diabetes following a 1 year randomised controlled exercise intervention, irrespective of changes in cardiorespiratory fitness

AIMS/HYPOTHESIS

Vascular changes in individuals with type 2 diabetes mellitus majorly contribute to the development of cardiovascular disease. Increased cardiorespiratory fitness (CRF) has been associated with improvements in vascular health. Although CRF tends to improve with exercise training, there remains a portion of participants with little or no improvement. Given the importance of vascular function in individuals with type 2 diabetes, we assessed whether individuals who failed to improve CRF following a 1 year exercise intervention also failed to improve arterial stiffness and structural indices.

METHODS

Individuals with type 2 diabetes with no major micro- and macrovascular complications and aged between 30 and 75 years old (n = 63) participated in a three-arm, 1 year, randomised controlled exercise intervention in Lisbon, Portugal. The study involved a non-exercise control group, a moderate continuous training combined with resistance training (RT) group and a high-intensity interval training with RT group. Allocation of participants into the intervention and control groups was done using a computer-generated list of random numbers. An improvement in CRF was defined as a change in [Formula: see text] ≥5%. Vascular stiffness and structural indices were measured using ultrasound imaging and applanation tonometry. Generalised estimating equations were used to compare changes in vascular measures across individuals in the control group (n = 22) and those in the exercise groups who either had improved CRF (CRF responders; n = 14) or whose CRF did not improve (CRF non-responders; n = 27) following 1 year of exercise training.

RESULTS

Compared with the control group, exercisers, with and without improvements in CRF, had decreased carotid intima-media thickness (IMT) (CRF responders: β = -2.84 [95% CI -5.63, -0.04]; CRF non-responders: β = -5.89 [95% CI -9.38, -2.40]) and lower-limb pulse wave velocity (PWV) (CRF responders: β = -0.14 [95% CI -0.25, -0.03]; CRF non-responders: β = -0.14 [95% CI -0.25, -0.03]), the latter being an indicator of peripheral arterial stiffness. Only CRF responders had decreased PWV of the upper limb compared with control participants (β = -0.12 [95% CI -0.23, -0.01]). As for central stiffness, CRF non-responders had increased aortic PWV compared with CRF responders (β = 0.19 [95% CI 0.07, 0.31]), whereas only the CRF non-responders had altered carotid distensibility coefficient compared with the control group (β = 0.00 [95% CI 3.01 × 10^-5, 0.00]). No interaction effects between the CRF responders and non-responders vs control group were found for the remaining stiffness or haemodynamic indices (p>0.05).

CONCLUSIONS/INTERPRETATION

Regardless of improvements in CRF, individuals with type 2 diabetes had significant improvements in carotid IMT and lower-limb arterial stiffness following a 1 year exercise intervention. Thus, a lack of improvement in CRF following exercise in people with type 2 diabetes does not necessarily entail a lack of improvement in vascular health.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03144505 FUNDING: This work was supported by fellowships from the Portuguese Foundation for Science and Technology. This work is also financed by a national grant through the Fundação para a Ciência e Tecnologia (FCT), within the unit I&D 472.

Renal outcomes with the newer antidiabetes drugs: the era before and after CREDENCE

In 2008, the US Food and Drug Administration provided guidance for the evaluation of the cardiovascular safety of antidiabetes drugs. The newer antidiabetes drugs, approved after 2008, were therefore evaluated in long-term cardiovascular outcome trials, designed and powered for the assessment of cardiovascular safety. Accordingly, the primary endpoint of these trials was a cardiac composite endpoint. Since 2008, the data from various cardiovascular outcome trials have been reported, including SAVOR-TIMI 53 (saxagliptin), EXAMINE (alogliptin), TECOS (sitagliptin), CARMELINA (linagliptin), CAROLINA (linagliptin), ELIXA (lixisenatide), LEADER (liraglutide), EXSCEL (exenatide once-weekly), SUSTAIN-6 (injectable semaglutide), HARMONY Outcomes (albiglutide), REWIND (dulaglutide), PIONEER-6 (oral semaglutide), EMPA-REG OUTCOME (empagliflozin), the CANVAS Program (canagliflozin) and DECLARE-TIMI 53 (dapagliflozin). Some of these trials subsequently also published data on renal outcomes, although these were secondary or exploratory analyses. Dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists had beneficial effects on albuminuria, while sodium-glucose co-transporter-2 inhibitors additionally showed a positive effect on 'hard' renal outcomes. In contrast to the cardiovascular outcome trials, the renal outcome trial of canagliflozin, CREDENCE, assessed a hard renal endpoint as its primary endpoint and showed positive effects on these hard renal outcomes. In this review, we aim to highlight the renal outcome data from the cardiovascular outcome trials and the CREDENCE trial and understand the differences between their results. The post CREDENCE era would appear to reinforce the position of sodium-glucose co-transporter-2 inhibitors as drugs providing cardiorenal protection, in addition to their anti-glycaemic effects.

Male and female sexual dysfunction in diabetic subjects: Focus on new antihyperglycemic drugs

The association between diabetes mellitus (and its micro- and macro-vascular complications) and erectile dysfunction is widely known and the presence of hypogonadism may further complicate sexual dysfunction and quality of life, given the association between hypogonadism and reduced libido, ejaculatory disorders, and depressive symptoms. However, the recent introduction of novel antidiabetic agents with a wide range of mechanism of action may have a significant impact both on male and female sexuality directly (by inducing side effects as urinary tract infections) and indirectly (improving metabolic status and reducing diabetes complications behind sexual dysfunctions). To date only few papers are reporting the sexual effects of these treatments and, often, these are not comparable in their results. Conversely, female sexual dysfunctions are somehow under-investigated. Data on prevalence is heterogeneous and specific pathogenic mechanisms, as well as the burden of psychological factors, are still heatedly debated. The aim of this narrative review is to summarize current knowledge and stressing out the need to diagnose male and female sexual dysfunctions also in light of the impact of treatments with novel antidiabetic agents. This would highlight the still unmet needs for sexual care in a diabetes care setting and could represent an incentive for future discussions, as well as a required theoretical starting point for studies on this subject.

Primary versus secondary cardiorenal prevention in type 2 diabetes: Which newer anti-hyperglycaemic drug matters?

We are observing a resurgence of major diabetic vascular complications after a period of dramatic decrease during the period 1990 to 2010. The classical division of cardiovascular prevention into primary (with an event) and secondary (without an event) is largely used to describe cardiovascular risk in type 2 diabetes (T2D); however, there is evidence that the cardiovascular risk in diabetes may range from highest in patients who experienced a previous cardiovascular event to mild in patients with the main risk factors at target. Herein, we present details of the 14 cardiovascular outcome trials (CVOTs) published to date, including the total population investigated, and their separation into primary (T2D + multiple risk factors) and secondary prevention (T2D + established cardiovascular disease [CVD]) populations as detailed within the trials. We also summarize evidence for the effects of dipeptidyl peptidase-4 inhibitors (DPP-4i), glucagon-like peptide-1 receptor agonists (GLP1-RA) and sodium glucose co-transporter-2 inhibitors (SGLT-2i) versus placebo on the risk of major cardiovascular events (MACE), heart failure (HF) and diabetic kidney disease (DKD). In primary prevention, SGLT-2i reduce both the risk of hospitalization for HF and progression of DKD; in secondary prevention, SGLT-2i are effective on the three endpoints, DPP-4i are neutral, while GLP1-RA show mixed results.

CTRP13 Preserves Endothelial Function by Targeting GTP Cyclohydrolase 1 in Diabetes

Endothelial dysfunction plays a crucial role in the progress of diabetic vasculopathy. C1q/tumor necrosis factor-related protein 13 (CTRP13) is a secreted adipokine that can ameliorate atherosclerosis and vascular calcification. However, the role of CTRP13 in regulating endothelial function in diabetes has yet to be explored. In this study, CTRP13 treatment improved endothelium-dependent relaxation in the aortae and mesenteric arteries of both db/db mice and streptozotocin-injected mice. CTRP13 supplement also rescued the impaired endothelium-dependent relaxation ex vivo in the db/db mouse aortae and in high glucose (HG)-treated mouse aortae. Additionally, CTRP13 treatment reduced reactive oxygen species overproduction and improved nitric oxide (NO) production and endothelial NO synthase (eNOS) coupling in the aortae of diabetic mice and in HG-treated human umbilical vein endothelial cells. Mechanistically, CTRP13 could increase GTP cyclohydrolase 1 (GCH1) expression and tetrahydrobiopterin (BH4) levels to ameliorate eNOS coupling. More importantly, CTRP13 rescued HG-induced inhibition of protein kinase A (PKA) activity. Increased PKA activity enhanced phosphorylation of the peroxisome proliferator-activated receptor α and its recruitment to the GCH1 promoter, thus activating GCH1 transcription and, ultimately, endothelial relaxation. Together, these results suggest that CTRP13 preserves endothelial function in diabetic mice by regulating GCH1/BH4 axis-dependent eNOS coupling, suggesting the therapeutic potential of CTRP13 against diabetic vasculopathy.

Cardiovascular Disease and Risk Management: Standards of Medical Care in Diabetes-2020

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc20-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc20-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Improved carotid intima-media thickness-induced high-intensity interval training associated with decreased serum levels of Dkk-1 and sclerostin in type 2 diabetes

AIMS

Carotid intima-media thickness (cIMT) is a validated surrogate marker of atherosclerosis. Dickkopf-1 (Dkk-1) and sclerostin modulate wingless signaling, which is involved in atherosclerosis. The purpose of this study was to investigate whether 12 weeks of high-intensity interval training (HIIT) would improve cIMT and serum Dkk-1 and sclerostin levels in patients with type 2 diabetes.

METHODS

Seventy-four sedentary patients with type 2 diabetes were randomly divided into HIIT and control groups. The HIIT group intervention was 6 intervals (4 min) at 85%-90% HR_max separated by 3 min at 45%-50% HR_max in 3 sessions/week for 12 weeks. Before and after the intervention, cIMT, artery diameter and wall/lm ratio were recorded with high-resolution ultrasound. Serum sclerostin and Dkk-1 were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

cIMT decreased significantly in the HIIT group (0.83 ± 0.17 baseline, 0.71 ± 0.14 follow-up) compared to the control group (0.84 ± 0.20 baseline, 0.85 ± 0.19 follow-up) (P < .05). Dkk-1 and sclerostin decreased significantly after 12 weeks of HIIT (P < .01). In addition, VO_2peak was increased in the HIIT group than the control group (by 6.2 mL/kg/min) (P < .05). There was a positive correlation between percent changes in cIMT and percent changes in Dkk-1 and sclerostin (both P < .01). Additionally, there were a negative correlation between percent changes VO2peak and cIMT (r = - 0.740, P = .003), Dkk-1 (r = - 0.844, P < .001) and sclerostin (r = - 0.575, P = .001) in HIIT group.

CONCLUSION

Our results indicate that HIIT decreases cIMT, serum levels of Dkk-1 and sclerostin and improves VO_2peak in patients with type 2 diabetes.

Effect of empagliflozin on brachial artery shear stress and endothelial function in subjects with type 2 diabetes: Results from an exploratory study

Empagliflozin reduces the risk of cardiovascular mortality in subjects with type 2 diabetes. We demonstrated that empagliflozin increases blood viscosity and carotid shear stress and decreases carotid wall thickness. Shear stress is the force acting on the endothelial surface and modulates arterial function. The current study evaluates the influence of empagliflozin on brachial artery shear stress and endothelial function compared to incretin-based therapy. The study is a nonrandomized, open, prospective cohort study including 35 subjects with type 2 diabetes administered empagliflozin or incretin-based therapy. Shear stress was calculated with a validated formula, and endothelial function was evaluated using the flow-mediated dilation technique. Both treatments resulted in comparable reductions in blood glucose and glycated haemoglobin. Brachial artery shear stress significantly increased exclusively in the empagliflozin group (61 ± 20 vs 68 ± 25 dynes/cm², p = 0.04), whereas no significant difference was detected in the incretin-based therapy group (60 ± 20 vs 55 ± 12 dynes/cm², p = not significant). Flow-mediated dilation significantly increased in the empagliflozin group (4.8 ± 4.5% vs 8.5 ± 5.6%, p = 0.03). Again, no change was detected in the incretin-based therapy group (5.1 ± 4.5% vs 4.7 ± 4.7%, p = not significant). The present findings demonstrate the beneficial effect of empagliflozin on shear stress and endothelial function in subjects with type 2 diabetes independent of the hypoglycaemic effect.

Beneficial Effects of Ipragliflozin on the Renal Function and Serum Uric Acid Levels in Japanese Patients with Type 2 Diabetes: A Randomized, 12-week, Open-label, Active-controlled Trial

Objective To examine the add-on effects, compared to the existing antidiabetes treatment, of the sodium-glucose cotransporter 2 inhibitor ipragliflozin on glycemic control and the risk factors of cardiovascular disease (CVD) and chronic kidney disease (CKD) in patients with inadequately controlled type 2 diabetes. Methods This 12-week, randomized, open-label, active-controlled trial included 30 patients with type 2 diabetes who were randomized 1:1 to ipragliflozin and control groups (n=15 each). The ipragliflozin group received 50 mg of ipragliflozin once daily in addition to conventional therapy. The primary outcome was the change in hemoglobin A1c (HbA1c) from the baseline. Secondary outcomes were changes from the baseline in indices of glycemic control, uric acid (UA), renal function, and arterial stiffness. Results The patients' diminished estimated glomerular filtration rate (eGFR) was alleviated in the ipragliflozin group compared to the control group [difference between groups (Δ) =4.6 (95% confidence interval (CI): 1.5-7.7) mL/min/1.73 m², p=0.006] prior to significant improvements in HbA1c and other parameters, including anthropometric indices and arterial stiffness. Furthermore, ipragliflozin add-on therapy resulted in a greater reduction in serum UA levels than control therapy [Δ=-52.3 (95% CI: -85.5-19.1) μmol/L, p=0.003]. The changes in the eGFR with ipragliflozin treatment were associated with ipragliflozin-mediated changes in the UA, even after adjusting for the age, sex, baseline HbA1c, baseline UA, and baseline eGFR (standardized regression coefficient=-0.535, p=0.010). Conclusion Ipragliflozin add-on therapy was associated with beneficial renal effects in parallel with reducing serum UA levels.

Sodium glucose co-transporter 2 inhibitors and cardiovascular event protections: how applicable are clinical trials and observational studies to real-world patients?

OBJECTIVE

This study evaluated the characteristics of new users of sodium glucose co-transporter 2 inhibitors (SGLT2i) in clinical practice to assess the applicability of the findings from clinical trials (Empagliflozin, Cardiovascular Outcomes and Mortality in Type 2 Diabetes (EMPA-REG OUTCOME) trial, Dapagliflozin Effect on Cardiovascular Events (DECLARE)-TIMI 58 trial, Canagliflozin Cardiovascular Assessment Study (CANVAS) program and the Evaluation of Ertugliflozin Efficacy and Safety Cardiovascular Outcomes (VERTIS-CV) trial) and multinational observational studies (CVD-REAL Nordic study and CVD-REAL 2 study).

RESEARCH DESIGN AND METHODS

We conducted a retrospective cohort study using the largest electronic medical records database from seven hospitals in Taiwan. We included adult patients with type 2 diabetes initiating canagliflozin, dapagliflozin and empagliflozin between 1 January 2018 and 31 August 2019. We compared the patient characteristics with SGLT2i to examine the data representativeness of clinical trials and to evaluate channeling uses between canagliflozin, dapagliflozin and empagliflozin.

RESULTS

We identified a cohort of 11 650 patients newly initiating SGLT2i, 49.9% of whom received empagliflozin. However, only 18.7%, 19.2%, 50.4% and 57.3% of real-world SGLT2i new users were included in the EMPA-REG OUTCOME trial, VERTIS-CV trial, DECLARE-TIMI 58 trial and CANVAS program, respectively. Reasons for exclusion were largely reduced cardiovascular disease risks in real-world patients, namely 72.8%, 73.6% and 34.2% for EMPA-REG OUTCOME trial, VERTIS-CV trial and DECLARE-TIMI 58 trial and CANVAS program, respectively. However, hemoglobin A1c out of range accounted for the most frequent reason (25.0%) for exclusion of real-world patients from the CANVAS program. We found channeling uses in different SGLT2i, for example, more patients receiving empagliflozin (15.3%) and canagliflozin (19.6%) had poorer renal functions (eg, estimated glomerular filtration rate <60 mL/min/1.73 m²), compared with dapagliflozin (9.3%).

CONCLUSIONS

The findings provide clear evidence that results from current studies may be less applicable to real-world patients. Further studies are required to support the concept of real-world cardiovascular event protection through SGLT2i.

Impact of the acute local inhibition of soluble epoxide hydrolase on diabetic skin microcirculatory dysfunction

The impact of the local inhibition of soluble epoxide hydrolase, which metabolizes vasodilator and anti-inflammatory epoxyeicosanoids, on diabetic skin microvascular dysfunction was assessed. In diabetic db/db mice, basal skin blood flow assessed using laser Doppler imaging was similar to that of control mice, but thermal hyperemia was markedly reduced. At 2 h after the topical administration of an aqueous gel containing the soluble epoxide hydrolase inhibitor trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB: 400 mg/L), the peak concentration of t-AUCB was detected in the skin of diabetic mice, which quickly decreased thereafter. In parallel, 2 h after application of t-AUCB treatment, thermal hyperemia was increased compared to the control gel. Quantification of t-AUCB in plasma of treated animals showed no or low systemic diffusion. Furthermore, haematoxylin and eosin histological staining of skin biopsies showed that skin integrity was preserved in t-AUCB-treated mice. Finally, for pig ear skin, a surrogate for human skin, using Franz diffusion cells, we observed a continuous diffusion of t-AUCB from 2 h after application to beyond 24 h. A single topical administration of a soluble epoxide hydrolase inhibitor improves microcirculatory function in the skin of db/db mice and might represent a new therapeutic approach for preventing the development of skin complications in diabetic patients.

Mediation analysis of time-to-event endpoints accounting for repeatedly measured mediators subject to time-varying confounding

In this article, we will present statistical methods to assess to what extent the effect of a randomised treatment (versus control) on a time-to-event endpoint might be explained by the effect of treatment on a mediator of interest, a variable that is measured longitudinally at planned visits throughout the trial. In particular, we will show how to identify and infer the path-specific effect of treatment on the event time via the repeatedly measured mediator levels. The considered proposal addresses complications due to patients dying before the mediator is assessed, due to the mediator being repeatedly measured, and due to posttreatment confounding of the effect of the mediator by other mediators. We illustrate the method by an application to data from the LEADER cardiovascular outcomes trial.

Cardiovascular outcome trials and major cardiovascular events: does glucose matter? A systematic review with meta-analysis

PURPOSE

We did a meta-analysis with meta-regression to evaluate the relationship between hemoglobin A1c (A1C) reduction and the primary CV outcome of cardiovascular outcome trials (CVOTs).

METHODS

We used a random effects meta-analysis of the 12 CVOTs to quantify the effect of A1C reduction on major cardiovascular events (MACE) risk by stratifying the difference in achieved A1C (drug vs placebo) in three strata: A1c < 0.3%, A1c ≥ 0.3% and < 0.5%, and A1c ≥ 0.5%.

RESULTS

We found a relation between the reduction in achieved A1C and the hazard ratio reduction for MACE (P = 0.002), explaining almost all (94.1%) the between-study variances: lowering A1C by 0.5% conferred a significant HRR of 20% (95% CI 4-33%) for MACE.

CONCLUSIONS

Blood glucose reduction may play a more important role than previously thought in reducing the risk of MACE during treatment with the newer glucose-lowering drugs, including peptidase-4 inhibitors, glucagon-like peptide 1 receptor agonists and sodium-glucose co-transporter-2 inhibitors.

Pharmacological treatment for Type 2 diabetes integrating findings from cardiovascular outcome trials: an expert consensus in the UK

In people with Type 2 diabetes, cardiovascular disease is a leading cause of morbidity and mortality. Thus, as well as controlling glucose, reducing the risk of cardiovascular events is a key goal. The results of cardiovascular outcome trials have led to updates for many national and international guidelines. England, Wales and Northern Ireland remain exceptions, with the most recent update to the National Institute for Health and Care Excellence (NICE) guidelines published in 2015. We reviewed current national and international guidelines and recommendations on the management of people with Type 2 diabetes. This article shares our consensus on clinical recommendations for the use of sodium-glucose co-transporter 2 inhibitors (SGLT-2is) and glucagon-like peptide 1 receptor agonists (GLP-1RAs) in people with Type 2 diabetes and established or at very high risk of cardiovascular disease in the UK. We also consider cost-effectiveness for these therapies. We recommend considering each person's cardiovascular risk and using diabetes therapies with proven cardiovascular benefits when appropriate to improve long-term outcomes and cost-effectiveness.