A Comparison of the Effects of the GLP-1 Analogue Liraglutide and Insulin Glargine on Endothelial Function and Metabolic Parameters: A Randomized, Controlled Trial Sapporo Athero-Incretin Study 2 (SAIS2)

The role of glucagon-like peptide-1 receptor agonists (GLP1-RAs) in the management of the hypertensive patient with metabolic syndrome: a position paper from the Korean society of hypertension

Obesity is the one of the most important components of metabolic syndrome. Because obesity related hypertension accounts for two thirds of essential hypertension, managing obesity and metabolic syndrome is a crucial task in the management of hypertension. However, the current non-pharmacological therapies have limitations for achieving or maintaining ideal body weight. Recently, glucagon-like peptide-1 receptor agonists (GLP1-RAs) have demonstrated excellent weight control effects, accompanied by corresponding reductions in blood pressure. GLP1-RAs have shown cardiovascular and renal protective effects in cardiovascular outcome trials both in primary and secondary prevention. In this document, the Korean Society of Hypertension intends to remark the current clinical results of GLP1-RAs and recommend the government and health-policy makers to define obesity as a disease and to establish forward-looking policies for GLP1-RA treatment for obesity treatment, including active reimbursement policies.

The effect of SGLT2 inhibitors and GLP1 receptor agonists on arterial stiffness: A meta-analysis of randomized controlled trials

BACKGROUND

Pulse wave velocity (PWV) and augmentation index (AIx) are indices used to assess arterial stiffness. We evaluated the effect of sodium glucose co-transporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP1-RA) on arterial stiffness indices.

METHODS

We searched PubMed (up to January 2024) for RCTs assessing the effect of SGLT2i or GLP1-RA on arterial stiffness with reporting outcomes PWV and AIx. Effect sizes of the included studies were expressed as weighted mean difference (WMD) and 95 % confidence interval. Subgroup analyses were performed based on comparator (placebo vs. active comparator), design (RCT vs. crossover), population (diabetic vs. all) and blindness (yes vs. no).

RESULTS

A total of 19 studies (SGLT2i, 12 studies; GLP1-RA, 5 studies; SGLT2i/GLP1-RA combination, 2 studies) assessing 1212 participants were included. We did not find any statistically significant association between GLP1-RA or SGLT2i and PWV or AIx. None of the subgroup analyses showed any statistically significant result.

CONCLUSION

No evidence of a favorable change in arterial stiffness indices (PWV, AIx) was found following the administration of SGLT2i or GLP1-RA.

GLP-1 receptor agonists and atherosclerosis protection: the vascular endothelium takes center stage

Atherosclerotic cardiovascular disease is a chronic condition that often copresents with type 2 diabetes and obesity. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are incretin mimetics endorsed by major professional societies for improving glycemic status and reducing atherosclerotic risk in people living with type 2 diabetes. Although the cardioprotective efficacy of GLP-1RAs and their relationship with traditional risk factors are well established, there is a paucity of publications that have summarized the potentially direct mechanisms through which GLP-1RAs mitigate atherosclerosis. This review aims to narrow this gap by providing comprehensive and in-depth mechanistic insight into the antiatherosclerotic properties of GLP-1RAs demonstrated across large outcome trials. Herein, we describe the landmark cardiovascular outcome trials that triggered widespread excitement around GLP-1RAs as a modern class of cardioprotective agents, followed by a summary of the origins of GLP-1RAs and their mechanisms of action. The effects of GLP-1RAs at each major pathophysiological milestone of atherosclerosis, as observed across clinical trials, animal models, and cell culture studies, are described in detail. Specifically, this review provides recent preclinical and clinical evidence that suggest GLP-1RAs preserve vessel health in part by preventing endothelial dysfunction, achieved primarily through the promotion of angiogenesis and inhibition of oxidative stress. These protective effects are in addition to the broad range of atherosclerotic processes GLP-1RAs target downstream of endothelial dysfunction, which include systemic inflammation, monocyte recruitment, proinflammatory macrophage and foam cell formation, vascular smooth muscle cell proliferation, and plaque development.

Vascular Aging: Assessment and Intervention

Vascular aging represents a collection of structural and functional changes in a blood vessel with advancing age, including increased stiffness, vascular wall remodeling, loss of angiogenic ability, and endothelium-dependent vasodilation dysfunction. These age-related alterations may occur earlier in those who are at risk for or have cardiovascular diseases, therefore, are defined as early or premature vascular aging. Vascular aging contributes independently to cardio-cerebral vascular diseases (CCVDs). Thus, early diagnosis and interventions targeting vascular aging are of paramount importance in the delay or prevention of CCVDs. Here, we review the direct assessment of vascular aging by examining parameters that reflect changes in structure, function, or their compliance with age including arterial wall thickness and lumen diameter, endothelium-dependent vasodilation, arterial stiffness as well as indirect assessment through pathological studies of biomarkers including endothelial progenitor cell, lymphocytic telomeres, advanced glycation end-products, and C-reactive protein. Further, we evaluate how different types of interventions including lifestyle mediation, such as caloric restriction and salt intake, and treatments for hypertension, diabetes, and hyperlipidemia affect age-related vascular changes. As a single parameter or intervention targets only a certain vascular physiological change, it is recommended to use multiple parameters to evaluate and design intervention approaches accordingly to prevent systemic vascular aging in clinical practices or population-based studies.

Effects of first-line antidiabetic drugs on the improvement of arterial stiffness: A Bayesian network meta-analysis

BACKGROUND

Changes in vascular function are closely associated with the development of cardiovascular disease (CVD). Pulse wave velocity (PWV) is a potential indicator of vascular dysfunction; it allows noninvasive assessment of arterial stiffness. Currently, evidence for the effects of different classes of antidiabetic drugs on arterial stiffness remains limited. In this study, a network meta-analysis (NMA) was performed to explore the associations between changes in arterial stiffness and first-line antidiabetic drugs by evaluating PWV in patients with different metabolic abnormalities.

METHODS

We systematically searched several electronic databases for randomized controlled trials (RCTs) published from inception until 25 August 2022, without language restrictions. The primary outcome was the change in PWV (ΔPWV) in all included studies; subgroup analysis was performed for patients with abnormal glucose metabolism, including prediabetes and diabetes mellitus. NMA was performed to calculate the mean differences (MDs) with 95% confidence intervals (CIs) as effect sizes to evaluate the ΔPWV.

RESULTS

Among the 2257 candidate articles identified in the initial search, 18 RCTs were eventually included in the analysis. In all studies, two classes of new antidiabetic drugs, glucagon-like peptide-1 receptor (GLP-1R) agonists and sSodium-glucose co-transporter 2 (SGLT-2) inhibitors, improved arterial stiffness by decreasing PWV compared with placebo (MD = -1.11, 95% CI: -1.94 to 0.28) and (MD = -0.76, 95% CI: -1.45 to -0.08). A conventional antidiabetic drug, metformin, also showed similar efficacy compared with placebo (MD = -0.73, 95% CI: -1.33 to -0.12). Finally, in subgroup studies of patients with abnormal glucose metabolism diseases, GLP-1R agonists (MD = -1.06, 95% CI: -2.05 to -0.10) significantly decreased PWV compared with placebo.

CONCLUSION

Three classes of antidiabetic drugs-GLP-1R agonists, SGLT-2 inhibitors, and metformin-have the potential to improve arterial stiffness. Among the six classes of antidiabetic drugs analyzed, GLP-1R agonists constitute the only class of drugs that improves arterial stiffness in patients with abnormal glucose metabolism diseases.

The effect of SGLT2 inhibitors, GLP1 agonists, and their sequential combination on cardiometabolic parameters: A randomized, prospective, intervention study

BACKGROUND

Pulse wave velocity (PWV) and augmentation index (AIx) are indices used to assess arterial stiffness. We aim to compare the effect of empagliflozin, liraglutide and their sequential combination on arterial stiffness indices in patients with type 2 diabetes (T2D).

METHODS

This was a randomized single blind study evaluating the effect of empagliflozin vs liraglutide in adult patients with T2D. Patients were randomized to liraglutide titrated gradually to 1.8 mg or empagliflozin 25 mg in 1:1 ratio. Three months later empagliflozin was added to the liraglutide group, and liraglutide was added to the empagliflozin group. Patients were assessed with non-invasive tests for arterial stiffness (i.e., carotid-femoral PWV and AIx of aortic pressure) at baseline, 3-month and 9-month visits (final visit was extended for 3 months from the initial design due to Covid 19 pandemic). The primary outcome was the between-group difference of PWV change (ΔPWV) and ΔAIx at 3 months. Secondary outcomes included the between-group difference of ΔPWV and ΔAIx at 9 months, as well as the ΔPWV and ΔAIx between baseline and 9-month visit when total study population was assessed.

RESULTS

A total of 62 patients with T2D (30 started liraglutide; 32 empagliflozin, mean age 63 years, 25 % with established cardiovascular disease) participated in the study. We failed to show any significant between-group differences of ΔPWV and ΔΑΙx at 3 and 9 months, as well as between-group difference of ΔPWV and ΔAIx for the total study population between baseline and 9-month visit. In contrast, systemic vascular resistance and lipoprotein(a) levels improved, showing better results with liraglutide than empagliflozin. Favorable effects were also observed on body weight, body mass index, body and visceral fat, blood pressure, HbA1c, and uric acid levels.

CONCLUSION

No evidence of a favorable change in arterial stiffness indices was seen with empagliflozin or liraglutide or their combination in this study. Well-designed powerful studies are needed to address any potential effects on arterial stiffness in selected populations.

Comparative effects of weight loss and incretin-based therapies on vascular endothelial function, fibrinolysis and inflammation in individuals with obesity and prediabetes: A randomized controlled trial

AIM

To test the hypothesis that glucagon-like peptide-1 receptor (GLP-1R) agonists have beneficial effects on vascular endothelial function, fibrinolysis and inflammation through weight loss-independent mechanisms.

MATERIALS AND METHODS

Individuals with obesity and prediabetes were randomized to 14 weeks of the GLP-1R agonist liraglutide, hypocaloric diet or the dipeptidyl peptidase-4 inhibitor sitagliptin in a 2:1:1 ratio. Treatment with drug was double blind and placebo-controlled. Measurements were made at baseline, after 2 weeks prior to significant weight loss and after 14 weeks. The primary outcomes were measures of endothelial function: flow-mediated vasodilation (FMD), plasminogen activator inhibitor-1 (PAI-1) and urine albumin-to-creatinine ratio (UACR).

RESULTS

Eighty-eight individuals were studied (liraglutide N = 44, diet N = 22, sitagliptin N = 22). Liraglutide and diet reduced weight, insulin resistance and PAI-1, while sitagliptin did not. There was no significant effect of any treatment on endothelial vasodilator function measured by FMD. Post hoc subgroup analyses in individuals with baseline FMD below the median, indicative of greater endothelial dysfunction, showed an improvement in FMD by all three treatments. GLP-1R antagonism with exendin (9-39) increased fasting blood glucose but did not change FMD or PAI-1. There was no effect of treatment on UACR. Finally, liraglutide, but not sitagliptin or diet, reduced the chemokine monocyte chemoattractant protein-1 (MCP-1).

CONCLUSION

Liraglutide and diet reduce weight, insulin resistance and PAI-1. Liraglutide, sitagliptin and diet do not change FMD in obese individuals with prediabetes with normal endothelial function. Liraglutide alone lowers the pro-inflammatory and pro-atherosclerotic chemokine MCP-1, indicating that this beneficial effect is independent of weight loss.

Cardiovascular effects of incretins - focus on GLP-1 receptor agonists

GLP-1 receptor agonists (GLP-1 RAs) have been used to treat patients with type 2 diabetes since 2005 and have become popular because of the efficacy and durability in relation to glycaemic control in combination with weight loss in most patients. Today in 2022, seven GLP-1 RAs, including oral semaglutide are available for treatment of type 2 diabetes. Since the efficacy in relation to reduction of HbA1c and body weight as well as tolerability and dosing frequency vary between agents, the GLP-1 RAs cannot be considered equal. The short acting lixisenatide showed no cardiovascular benefits, while once daily liraglutide and the weekly agonists, subcutaneous semaglutide, dulaglutide, and efpeglenatide, all lowered the incidence of cardiovascular events. Liraglutide, oral semaglutide and exenatide once weekly also reduced mortality. GLP-1 RAs reduce the progression of diabetic kidney disease. In the 2019 consensus report from EASD/ADA, GLP-1 RAs with demonstrated cardio-renal benefits (liraglutide, semaglutide and dulaglutide) are recommended after metformin to patients with established cardiovascular diseases or multiple cardiovascular risk factors. European Society of Cardiology (ESC) suggests starting with a SGLT-2 inhibitor or a GLP-1 RA in drug naïve patients with type 2 diabetes and atherosclerotic CVD or high CV Risk. However, the results from cardiovascular outcome trials (CVOT) are very heterogeneous suggesting that some GLP-1RA are more suitable to prevent CVD than others. The CVOTs provide a basis upon which individual treatment decisions for patients with T2D and CVD can be made.

Obesity and Endothelial Function

Obesity is a major public health problem and is related to increasing rates of cardiovascular morbidity and mortality. Over 1.9 billion adults are overweight or obese worldwide and the prevalence of obesity is increasing. Obesity influences endothelial function through obesity-related complications such as hypertension, dyslipidemia, diabetes, metabolic syndrome, and obstructive sleep apnea syndrome. The excess fat accumulation in obesity causes adipocyte dysfunction and induces oxidative stress, insulin resistance, and inflammation leading to endothelial dysfunction. Several anthropometric indices and imaging modalities that are used to evaluate obesity have demonstrated an association between obesity and endothelial function. In the past few decades, there has been great focus on the mechanisms underlying endothelial dysfunction caused by obesity for the prevention and treatment of cardiovascular events. This review focuses on pathophysiological mechanisms of obesity-induced endothelial dysfunction and therapeutic targets of obesity.

Comparison of the effects of empagliflozin and glimepiride on endothelial function in patients with type 2 diabetes: A randomized controlled study

Patients with type 2 diabetes who have cardiovascular disease and are receiving empagliflozin have a lower rate of primary composite cardiovascular outcomes. In contrast, glimepiride increases cardiovascular hospitalization when combined with metformin. Here, we assessed the effects of empagliflozin and glimepiride on endothelial function using flow-mediated dilation (FMD). In this prospective, open-label, randomized, parallel-group study, 63 patients with type 2 diabetes received metformin and insulin glargine U100 for 12 weeks. This was followed by additional treatment with empagliflozin or glimepiride for 12 weeks. The primary outcome was the change in the FMD measurement (ΔFMDs) at 24 weeks of additional treatment. Secondary outcomes comprised changes in metabolic markers and body composition. The empagliflozin group (n = 33) and glimepiride group (n = 30) showed no significant differences in ΔFMDs (empagliflozin, −0.11 [95%CI: -1.02, 0.80]%; glimepiride, −0.34 [95%CI: -1.28, 0.60]%; P = 0.73). Additionally, changes in glycated hemoglobin were similar between the two groups. However, a significant difference in body weight change was observed (empagliflozin, −0.58 [95%CI: -1.60, 0.43] kg; glimepiride, 1.20 [95%CI: 0.15, 2.26] kg; P = 0.02). Moreover, a body composition analysis revealed that body fluid volume significantly decreased after empagliflozin treatment (baseline, 35.8 ± 6.8 L; after 12 weeks, −0.33 ± 0.72 L; P = 0.03). Hence, although empagliflozin did not improve endothelial function compared with glimepiride for patients with type 2 diabetes, it did decrease body fluid volumes. Thus, the coronary-protective effect of empagliflozin is not derived from endothelial function protection, but rather from heart failure risk reduction.

Trial registration: This trial was registered on September 13, 2016; UMIN000024001.

Effect of glycemic control on markers of subclinical atherosclerosis in patients with type 2 diabetes mellitus: A review

Cardiovascular disease is the predominant cause of death in type 2 diabetes mellitus (T2DM). Evidence suggests a strong association between duration and degree of hyperglycemia and vascular disease. However, large trials failed to show cardiovascular benefit after intensive glycemic control, especially in patients with longer diabetes duration. Atherosclerosis is a chronic and progressive disease, with a long asymptomatic phase. Subclinical atherosclerosis, which is impaired in T2DM, includes impaired vasodilation, increased coronary artery calcification (CAC), carotid intima media thickness, arterial stiffness, and reduced arterial elasticity. Each of these alterations is represented by a marker of subclinical atherosclerosis, offering a cost-effective alternative compared to classic cardiac imaging. Their additional use on top of traditional risk assessment strengthens the predictive risk for developing coronary artery disease (CAD). We, herein, review the existing literature on the effect of glycemic control on each of these markers separately. Effective glycemic control, especially in earlier stages of the disease, attenuates progression of structural markers like intima-media thickness and CAC. Functional markers are improved after use of newer anti-diabetic agents, such as incretin-based treatments or sodium-glucose co-transporter-2 inhibitors, especially in T2DM patients with shorter disease duration. Larger prospective trials are needed to enhance causal inferences of glycemic control on clinical endpoints of CAD.

Diabetes pathogenesis and management: the endothelium comes of age

Endothelium, acting as a barrier, protects tissues against factors that provoke insulin resistance and type 2 diabetes and itself responds to the insult of insulin resistance inducers with altered function. Endothelial insulin resistance and vascular dysfunction occur early in the evolution of insulin resistance-related disease, can co-exist with and even contribute to the development of metabolic insulin resistance, and promote vascular complications in those affected. The impact of endothelial insulin resistance and vascular dysfunction varies depending on the blood vessel size and location, resulting in decreased arterial plasticity, increased atherosclerosis and vascular resistance, and decreased tissue perfusion. Women with insulin resistance and diabetes are disproportionately impacted by cardiovascular disease, likely related to differential sex-hormone endothelium effects. Thus, reducing endothelial insulin resistance and improving endothelial function in the conduit arteries may reduce atherosclerotic complications, in the resistance arteries lead to better blood pressure control, and in the microvasculature lead to less microvascular complications and more effective tissue perfusion. Multiple diabetes therapeutic modalities, including medications and exercise training, improve endothelial insulin action and vascular function. This action may delay the onset of type 2 diabetes and/or its complications, making the vascular endothelium an attractive therapeutic target for type 2 diabetes and potentially type 1 diabetes.

Endothelial Dysfunction in Atherosclerotic Cardiovascular Diseases and Beyond: From Mechanism to Pharmacotherapies

The endothelium, a cellular monolayer lining the blood vessel wall, plays a critical role in maintaining multiorgan health and homeostasis. Endothelial functions in health include dynamic maintenance of vascular tone, angiogenesis, hemostasis, and the provision of an antioxidant, anti-inflammatory, and antithrombotic interface. Dysfunction of the vascular endothelium presents with impaired endothelium-dependent vasodilation, heightened oxidative stress, chronic inflammation, leukocyte adhesion and hyperpermeability, and endothelial cell senescence. Recent studies have implicated altered endothelial cell metabolism and endothelial-to-mesenchymal transition as new features of endothelial dysfunction. Endothelial dysfunction is regarded as a hallmark of many diverse human panvascular diseases, including atherosclerosis, hypertension, and diabetes. Endothelial dysfunction has also been implicated in severe coronavirus disease 2019. Many clinically used pharmacotherapies, ranging from traditional lipid-lowering drugs, antihypertensive drugs, and antidiabetic drugs to proprotein convertase subtilisin/kexin type 9 inhibitors and interleukin 1β monoclonal antibodies, counter endothelial dysfunction as part of their clinical benefits. The regulation of endothelial dysfunction by noncoding RNAs has provided novel insights into these newly described regulators of endothelial dysfunction, thus yielding potential new therapeutic approaches. Altogether, a better understanding of the versatile (dys)functions of endothelial cells will not only deepen our comprehension of human diseases but also accelerate effective therapeutic drug discovery. In this review, we provide a timely overview of the multiple layers of endothelial function, describe the consequences and mechanisms of endothelial dysfunction, and identify pathways to effective targeted therapies. SIGNIFICANCE STATEMENT: The endothelium was initially considered to be a semipermeable biomechanical barrier and gatekeeper of vascular health. In recent decades, a deepened understanding of the biological functions of the endothelium has led to its recognition as a ubiquitous tissue regulating vascular tone, cell behavior, innate immunity, cell-cell interactions, and cell metabolism in the vessel wall. Endothelial dysfunction is the hallmark of cardiovascular, metabolic, and emerging infectious diseases. Pharmacotherapies targeting endothelial dysfunction have potential for treatment of cardiovascular and many other diseases.

The preventive effect of liraglutide on the lipotoxic liver injury via increasing autophagy

INTRODUCTION AND OBJECTIVES

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing. Previous studies indicated that Liraglutide, glucagon-like peptide-1 analogue, could regulate glucose homeostasis as a valuable treatment for Type 2 Diabetes. However, the precise effect of Liraglutide on NAFLD model in rats and the mechanism remains unknown. In this study, we investigated the molecular mechanism by which Liraglutide ameliorates hepatic steatosis in a high-fat diet (HFD)-induced rat model of NAFLD in vivo and in vitro.

MATERIALS AND METHODS

NALFD rat models and hepatocyte steatosis in HepG2 cells were induced by HFD and palmitate fatty acid treatment, respectively. AMPK inhibitor, Compound C was added in HepG2 cells. Autophagy-related proteins LC3, Beclin1 and Atg7, and AMPK pathway-associated proteins were evaluated by Western blot and RT-PCR.

RESULTS

Liraglutide enhanced autophagy as showed by the increased expression of the autophagy markers LC3, Beclin1 and Atg7 in HFD rats and HepG2 cells treated with palmitate fatty acid. In vitro, The AMPK inhibitor exhibited an inhibitory effect on Liraglutide-induced autophagy enhancement with the deceased expression of LC3, Beclin1 and Atg7. Additionally, Liraglutide treatment elevated AMPK levels and TSC1, decreased p-mTOR expression.

CONCLUSIONS

Liraglutide could upregulate autophagy to decrease lipid over-accumulation via the AMPK/mTOR pathway.

Effects of Basal Insulin on Lipid Profile Compared to Other Classes of Antihyperglycemic Agents in Type 2 Diabetic Patients

OBJECTIVE

The lipid profile represents a driver of cardiovascular risk in type 2 diabetes. The effect of chronic insulin therapy on cholesterol levels is unclear. We aim to evaluate the effect of basal insulin on lipid profile compared to other classes of antihyperglycemic agents in type 2 diabetic patients.

DESIGN

We performed a meta-analysis of randomized controlled trials reporting changes of lipid parameters in type 2 diabetic patients randomly assigned to basal insulin or other classes of anti-hyperglycemic agents.

RESULTS

The levels of total (TC) and low-density lipoprotein cholesterol (LDL-C) appeared to be significantly reduced by therapies with glucagon-like peptide-1 receptor agonists (GLP-1RA) in comparison to basal insulin (mean difference [MD] -3.80; 95% CI [-6.30 to -1.30] mg/dL, P < .001 and -4.17; 95% CI [-6.04 to -2.30] mg/dL, P < .0001), whereas no difference was detected between basal insulin and dipeptidyl peptidase-4 inhibitors (DPP4-I) or standard therapy (sulfonylurea ± metformin). Thiazolidinediones (TZD) produced a significant improvement in high-density lipoprotein cholesterol (HDL-C) (MD 3.55; 95% CI: 0.55 to 6.56 mg/dL, P = .02) but were associated with an increase in TC and LDL-C (MD 16.20; 95% CI: 9.09 to 23.31 mg/dL, P < .001 and 5.19: 95% CI: -3.00 to 13.39 mg/dL, P = .21). Basal insulin was superior to standard therapy in triglyceride reduction (MD 3.8; 95% CI: 0.99 to 6.63 mg/dL, P = .008).

CONCLUSIONS

GLP-1RA were superior to basal insulin in the control of TC and LDL-C. Basal insulin effectively reduced serum triglycerides. TZD led to improvement in HDL-C. DPP4-I and standard therapy did not have any significant effect on lipid levels.

Circulating Cardiac Biomarkers in Diabetes Mellitus: A New Dawn for Risk Stratification-A Narrative Review

The aim of this narrative review is to update the current knowledge on the differential choice of circulating cardiac biomarkers in patients with prediabetes and established type 2 diabetes mellitus (T2DM). There are numerous circulating biomarkers with unconfirmed abilities to predict clinical outcomes in pre-DM and DM individuals; the prognostication ability of the cardiac biomarkers reported here has been established, and they are still being studied. The conventional cardiac biomarkers, such as natriuretic peptides (NPs), soluble suppressor tumorigenisity-2, high-sensitivity circulating cardiac troponins and galectin-3, were useful to ascertain cardiovascular (CV) risk. Each cardiac biomarker has its strengths and weaknesses that affect the price of usage, specificity, sensitivity, predictive value and superiority in face-to-face comparisons. Additionally, there have been confusing reports regarding their abilities to be predictably relevant among patients without known CV disease. The large spectrum of promising cardiac biomarkers (growth/differential factor-15, heart-type fatty acid-binding protein, cardiotrophin-1, carboxy-terminal telopeptide of collagen type 1, apelin and non-coding RNAs) is discussed in the context of predicting CV diseases and events in patients with known prediabetes and T2DM. Various reasons have been critically discussed related to the variable findings regarding biomarker-based prediction of CV risk among patients with metabolic disease. It was found that NPs and hs-cTnT are still the most important tools that have an affordable price as well as high sensitivity and specificity to predict clinical outcomes among patients with pre-DM and DM in routine clinical practice, but other circulating biomarkers need to be carefully investigated in large trials in the future.

When Good Guys Turn Bad: Bone Marrow's and Hematopoietic Stem Cells' Role in the Pathobiology of Diabetic Complications

Diabetes strongly contributes to the development of cardiovascular disease, the leading cause of mortality and morbidity in these patients. It is widely accepted that hyperglycemia impairs hematopoietic stem/progenitor cell (HSPC) mobilization from the bone marrow (BM) by inducing stem cell niche dysfunction. Moreover, a recent study demonstrated that type 2 diabetic patients are characterized by significant depletion of circulating provascular progenitor cells and increased frequency of inflammatory cells. This unbalance, potentially responsible for the reduction of intrinsic vascular homeostatic capacity and for the establishment of a low-grade inflammatory status, suggests that bone BM-derived HSPCs are not only victims but also active perpetrators in diabetic complications. In this review, we will discuss the most recent literature on the molecular mechanisms underpinning hyperglycemia-mediated BM dysfunction and differentiation abnormality of HSPCs. Moreover, a section will be dedicated to the new glucose-lowering therapies that by specifically targeting the culprits may prevent or treat diabetic complications.

Endothelium as a Therapeutic Target in Diabetes Mellitus: From Basic Mechanisms to Clinical Practice

Endothelium plays an essential role in human homeostasis by regulating arterial blood pressure, distributing nutrients and hormones as well as providing a smooth surface that modulates coagulation, fibrinolysis and inflammation. Endothelial dysfunction is present in Diabetes Mellitus (DM) and contributes to the development and progression of macrovascular disease, while it is also associated with most of the microvascular complications such as diabetic retinopathy, nephropathy and neuropathy. Hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia are the main factors involved in the pathogenesis of endothelial dysfunction. Regarding antidiabetic medication, metformin, gliclazide, pioglitazone, exenatide and dapagliflozin exert a beneficial effect on Endothelial Function (EF); glimepiride and glibenclamide, dipeptidyl peptidase-4 inhibitors and liraglutide have a neutral effect, while studies examining the effect of insulin analogues, empagliflozin and canagliflozin on EF are limited. In terms of lipid-lowering medication, statins improve EF in subjects with DM, while data from short-term trials suggest that fenofibrate improves EF; ezetimibe also improves EF but further studies are required in people with DM. The effect of acetylsalicylic acid on EF is dose-dependent and lower doses improve EF while higher ones do not. Clopidogrel improves EF, but more studies in subjects with DM are required. Furthermore, angiotensin- converting-enzyme inhibitors /angiotensin II receptor blockers improve EF. Phosphodiesterase type 5 inhibitors improve EF locally in the corpus cavernosum. Finally, cilostazol exerts favorable effect on EF, nevertheless, more data in people with DM are required.

Acute Exenatide Therapy Attenuates Postprandial Vasodilation in Humans with Prediabetes: A Randomized Controlled Trial

Background: The state of prediabetes comprises atherosclerotic changes leading to decreased vascular function in humans. This study examined the effects on incretin mimetics on vascular physiology in the prediabetic postprandial state. Methods: Fifteen obese adults with prediabetes participated in a randomized, crossover, double-blinded trial comparing the postprandial effects of exenatide, saxagliptin, and placebo on peripheral vasodilation. All studies utilized a standardized high-fat meal. Resting and peak forearm blood flow (FBF) were measured via strain gauge venous occlusion plethysmography, and makers of vascular dysfunction were measured in plasma. Results: Exenatide attenuated resting FBF at 3 hr (P = 0.003) and 6 hr (P = 0.056) postmeal, compared to placebo. Nonsignificant reductions in resting FBF were observed between saxagliptin and placebo at the same time points. No group differences were observed for peak FBF, plasma nitrotyrosine, and plasma 8-iso-prostaglandin F2alpha. A transient increase in plasma triglyceride was abated in the exenatide group, when compared to saxagliptin and placebo groups. Only exenatide group showed no significant upsurge in plasma insulin. Plasma-free fatty acids significantly declined in all three groups, although less markedly for exenatide. Postmeal glucose increased at 2 hr with placebo and saxagliptin, but simultaneously decreased with exenatide. Conclusions: Acute treatment with exenatide blunted the postprandial vasodilatory effect of a high-fat meal in prediabetes. Exenatide's acute effects derived primarily from multiple endothelium-independent processes. Trial Registration Number: NCT02104739.

Why the endothelium? The endothelium as a target to reduce diabetes-associated vascular disease

Over the past 66 years, our knowledge of the role of the endothelium in the regulation of cardiovascular function and dysfunction has advanced from the assumption that it is a single layer of cells that serves as a barrier between the blood stream and vascular smooth muscle to an understanding of its role as an essential endocrine-like organ. In terms of historical contributions, we pay particular credit to (1) the Canadian scientist Dr. Rudolf Altschul who, based on pathological changes in the appearance of the endothelium, advanced the argument in 1954 that "one is only as old as one's endothelium" and (2) the American scientist Dr. Robert Furchgott, a 1998 Nobel Prize winner in Physiology or Medicine, who identified the importance of the endothelium in the regulation of blood flow. This review provides a brief history of how our knowledge of endothelial function has advanced and now recognize that the endothelium produces a plethora of signaling molecules possessing paracrine, autocrine, and, arguably, systemic hormone functions. In addition, the endothelium is a therapeutic target for the anti-diabetic drugs metformin, glucagon-like peptide I (GLP-1) receptor agonists, and inhibitors of the sodium-glucose cotransporter 2 (SGLT2) that offset the vascular disease associated with diabetes.

The effect of DPP-4-protected GLP-1 (7-36) on coronary microvascular function in obese adults

Objective

Glucagon-like-peptide-1 (GLP-1) receptor analogues have been shown to reduce cardiovascular events in patients with type 2 diabetes. However, the mechanism behind is still unknown. The aim of the study was to investigate the effect of intact GLP-1 (7-36) on coronary microcirculation in overweight adults.

Design and methods

A double-blinded randomized cross-over study was performed, with 12 overweight participants. Effects of intact GLP-1 (7-36) infusion were compared with a saline infusion on separate days. A DPP-4 inhibitor was administered to block degradation of intact GLP-1 (7-36) to the GLP-1 metabolite (9-36). Coronary microcirculation was assessed by Doppler coronary flow velocity reserve (CFVR) before and after 2 h of infusion. Peripheral endothelial function was assessed by flow mediated dilation (FMD) before and after one hour of infusion.

Results

CFVR was 3.77 ± 1.25 during GLP-1 infusion and 3.85 ± 1.32 during saline infusion, endothelial function was 16.3 ± 15.5 % during GLP-1 infusion and 7.85 ± 7.76 % during saline infusion. When adjusting for baseline values no significant differences in CFVR (ΔCFVR 0.38 ± 0.92 vs. ΔCFVR 0.71 ± 1.03, p = 0.43) and no difference in peripheral endothelial function (ΔFMD 7.34 ± 11.5 % vs. ΔFMD -1.25 ± 9.23%, p = 0.14) was found.

Conclusions

We found no effect of intact GLP-1 (7-36), protected from DPP4 mediated degradation on coronary microcirculation in overweight adults.

The Ascending GLP-1 Road From Clinical Safety to Reduction of Cardiovascular Complications

Glucagon-like peptide 1 (GLP-1) was originally identified as a gut-derived incretin hormone that lowered glycemia through potentiation of glucose-dependent insulin secretion. Subsequent studies expanded the actions of GLP-1 to include inhibition of glucagon secretion, gastric emptying, and appetite, collectively useful attributes for a glucose-lowering agent. The introduction of GLP-1 receptor (GLP-1R) agonists for the treatment of diabetes was associated with questions surrounding their safety, principally with regard to medullary thyroid cancer, pancreatitis, and pancreatic cancer, yet cardiovascular outcome trials subsequently revealed reductions in rates of stroke, myocardial infarction, and cardiovascular death with a paucity of major safety signals. We discuss the controversies, unanswered questions, and established use of GLP-1R agonists from a mechanistic and clinical perspective. We highlight methods for detection and cellular sites of GLP-1R expression, key uncertainties, recent insights, and experimental caveats surrounding the use of GLP-1R agonists for the treatment of diabetes and the reduction of diabetes-related complications.

After the LEADER trial and SUSTAIN-6, how do we explain the cardiovascular benefits of some GLP-1 receptor agonists?

Recent cardiovascular outcome trials - the LEADER with liragutide and SUSTAIN-6 with semaglutide - have shown significant reductions of major cardiovascular (CV) events with these glucagon-like peptide (GLP)-1 receptor agonists. Progressive separation of the treatment and placebo curves, starting clearly between 12 and 18 months of the trial period, and significant reductions in the risk of myocardial infarction and stroke, indicate that the beneficial CV effects observed with GLP-1 receptor agonists could be due to an antiatherogenic effect. So far, the reasons for such an effect of GLP-1 receptor agonists have not been entirely clear, although several hypotheses may be proposed. As the reductions in glycated haemoglobin and systolic blood pressure (SBP) in these trials were modest, and both trials lasted only a short period of time, reductions in hyperglycaemia and SBP are unlikely to be involved in the beneficial CV effects of GLP-1 receptor agonists. On the other hand, their effect on lipids and, in particular, the dramatic decrease in postprandial hypertriglyceridaemia may explain their beneficial CV actions. Reduction of body weight, including a significant decrease in visceral fat in patients using GLP-1 receptor agonists, may also have beneficial CV effects by reducing chronic proatherogenic inflammation. In addition, there are in-vitro data showing a direct anti-inflammatory effect with these agents that could also be involved in their beneficial CV effects. Moreover, studies in humans have shown significant beneficial effects on ischaemic myocardium after a very short treatment period, suggesting a direct effect of GLP-1 receptor agonists on myocardium, although the precise mechanism remains unclear. Finally, as a reduction in insulin resistance has been associated with a decrease in CV risk, it cannot be ruled out that the lowering of insulin resistance induced by GLP-1 receptor agonists might also be involved in their beneficial CV actions.

The Effects of Exenatide and Metformin on Endothelial Function in Newly Diagnosed Type 2 Diabetes Mellitus Patients: A Case-Control Study

INTRODUCTION

Exenatide is a new antidiabetic glucagon-like peptide-1 receptor agonist. In addition to its hypoglycemic effect, exenatide may have a potential protective benefit on vascular endothelial function. This study attempted to compare the effects of exenatide and traditional antidiabetic drug metformin treatment on endothelial function in overweight patients with type 2 diabetes.

METHODS

Ninety overweight patients with newly diagnosed type 2 diabetes were recruited; 45 patients received exenatide (Exe) treatment and 45 patients received metformin (Met) treatment for 12 weeks. The control groups included 37 overweight and 24 non-overweight individuals. The parameters of glucose and lipid metabolism and endothelial function were measured before and after treatment. Vascular endothelial dysfunction was measured by reactive hyperemia index.

RESULTS

Newly diagnosed patients with type 2 diabetes had more serious vascular endothelial dysfunction than both overweight and normal-weight control groups. The levels of body mass index, glucose, HbA1c, homeostasis model assessment insulin resistance, and homeostasis model assessment β-cell function were improved significantly by both exenatide and metformin treatment. Both exenatide and metformin treatment can improve vascular endothelial function (Exe group: 1.67 ± 0.52 vs 1.98 ± 0.67, P < 0.05; Met group: 1.68 ± 0.29 vs 1.82 ± 0.24, P < 0.05). Exenatide treatment was no less effective than metformin in improving endothelial function (0.31 ± 0.70 vs 0.13 ± 0.24, P > 0.05).

CONCLUSIONS

Newly diagnosed patients with type 2 diabetes may have vascular endothelial dysfunction. Both exenatide and metformin treatment can improve vascular endothelial dysfunction, and exenatide was no less effective than metformin treatment.

Effects of 6-month treatment with the glucagon like peptide-1 analogue liraglutide on arterial stiffness, left ventricular myocardial deformation and oxidative stress in subjects with newly diagnosed type 2 diabetes

Background

Incretin-based therapies are used in the treatment of type 2 diabetes mellitus (T2DM) and obesity. We investigated the changes in arterial stiffness and left ventricular (LV) myocardial deformation after 6-month treatment with the GLP-1 analogue liraglutide in subjects with newly diagnosed T2DM.

Methods

We randomized 60 patients with newly diagnosed and treatment-naive T2DM to receive either liraglutide (n = 30) or metformin (n = 30) for 6 months. We measured at baseline and after 6-month treatment: (a) carotid-femoral pulse wave velocity (PWV) (b) LV longitudinal strain (GLS), and strain rate (GLSR), peak twisting (pTw), peak twisting velocity (pTwVel) and peak untwisting velocity (pUtwVel) using speckle tracking echocardiography. LV untwisting was calculated as the percentage difference between peak twisting and untwisting at MVO (%dpTw–Utw_MVO), at peak (%dpTw–Utw_PEF) and end of early LV diastolic filling (%dpTw–Utw_EDF) (c) Flow mediated dilatation (FMD) of the brachial artery and percentage difference of FMD (FMD%) (d) malondialdehyde (MDA), protein carbonyls (PCs) and NT-proBNP.

Results

After 6-months treatment, subjects that received liraglutide presented with a reduced PWV (11.8 ± 2.5 vs. 10.3 ± 3.3 m/s), MDA (0.92 [0.45–2.45] vs. 0.68 [0.43–2.08] nM/L) and NT-proBNP (p < 0.05) in parallel with an increase in GLS (− 15.4 ± 3 vs. − 16.6 ± 2.7), GLSR (0.77 ± 0.2 vs. 0.89 ± 0.2), pUtwVel (− 97 ± 49 vs. − 112 ± 52°, p < 0.05), %dpTw–Utw_MVO (31 ± 10 vs. 40 ± 14), %dpTw–Utw_PEF (43 ± 19 vs. 53 ± 22) and FMD% (8.9 ± 3 vs. 13.2 ± 6, p < 0.01). There were no statistically significant differences of the measured markers in subjects that received metformin except for an improvement in FMD. In all subjects, PCs levels at baseline were negatively related to the difference of GLS (r = − 0.53) post-treatment and the difference of MDA was associated with the difference of PWV (r = 0.52) (p < 0.05 for all associations) after 6-month treatment.

Conclusions

Six-month treatment with liraglutide improves arterial stiffness, LV myocardial strain, LV twisting and untwisting and NT-proBNP by reducing oxidative stress in subjects with newly diagnosed T2DM.

ClinicalTrials.gov Identifier NCT03010683

Effects of Newer Antidiabetic Drugs on Endothelial Function and Arterial Stiffness: A Systematic Review and Meta-Analysis

BACKGROUND

Newer antidiabetic drugs, i.e., dipeptidyl peptidase-4 (DPP-4) inhibitors, sodium-glucose cotransporter-2 (SGLT-2) inhibitors, and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) may exert distinct cardiovascular effects. We sought to explore their impact on vascular function.

METHODS

Published literature was systematically searched up to January 2018 for clinical studies assessing the effects of DPP-4 inhibitors, GLP-1 RAs, and SGLT-2 inhibitors on endothelial function and arterial stiffness, assessed by flow-mediated dilation (FMD) of the brachial artery and pulse wave velocity (PWV), respectively. For each eligible study, we used the mean difference (MD) with 95% confidence intervals (CIs) for FMD and PWV. The pooled MD for FMD and PWV were calculated by using a random-effect model. The presence of heterogeneity among studies was evaluated by the I ² statistic.

RESULTS

A total of 26 eligible studies (n = 668 patients) were included in the present meta-analysis. Among newer antidiabetic drugs, only SGLT-2 inhibitors significantly improved FMD (pooled MD 1.14%, 95% CI: 0.18 to 1.73, p = 0.016), but not DPP-4 inhibitors (pooled MD = 0.86%, 95% CI: -0.15 to 1.86, p = 0.095) or GLP-1 RA (pooled MD = 2.37%, 95% CI: -0.51 to 5.25, p = 0.107). Both GLP-1 RA (pooled MD = -1.97, 95% CI: -2.65 to -1.30, p < 0.001) and, to a lesser extent, DPP-4 inhibitors (pooled MD = -0.18, 95% CI: -0.30 to -0.07, p = 0.002) significantly decreased PWV.

CONCLUSIONS

Newer antidiabetic drugs differentially affect endothelial function and arterial stiffness, as assessed by FMD and PWV, respectively. These findings could explain the distinct effects of these drugs on cardiovascular risk of patients with type 2 diabetes.

Randomized Trial of the Effects of Insulin and Metformin on Myocardial Injury and Stress in Diabetes Mellitus: A Post Hoc Exploratory Analysis

Background

Subclinical myocardial injury, as measured by high‐sensitivity cardiac troponin T (hsTnT), and myocardial stress, as measured by N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP), are related to glycemic control in patients with type 2 diabetes mellitus, and are strong predictors of adverse cardiovascular outcomes. We sought to determine whether antihyperglycemic therapy improves measures of myocardial injury and myocardial stress in patients with type 2 diabetes mellitus.

Methods and Results

We randomized, in a 2×2 factorial fashion, 438 patients with type 2 diabetes mellitus to insulin glargine, metformin, the combination, or placebo and measured changes in NT‐proBNP and hsTnT after 12 weeks of therapy. At baseline, the median (Q1–Q3) plasma concentration was 35.4 (15.7–86.3) ng/L for NT‐proBNP and 6.7 (4.6–10.1) ng/L for hsTnT. The adjusted (95% confidence interval) change in NT‐proBNP concentration was 20.7% (7.9–35.0) in the insulin arm compared with 0.13% (−10.8 to 12.5) in the no‐insulin arm (P=0.03 for comparison). These changes were not related to changes in fasting or postprandial glucose, glycated hemoglobin, weight, blood pressure, or inflammation. In the metformin arm, the adjusted change in NT‐proBNP was 7.8% (−3.7 to 20.7) compared with 13.0% (0.72–26.8) in the no‐metformin arm (P=0.58). No significant changes in hsTnT concentrations were observed for any of the treatment arms.

Conclusions

Insulin glargine was associated with a significant 20.7% increase in NT‐proBNP, a marker of myocardial stress, after 12 weeks of therapy. No change in hsTnT, a marker of myocardial injury, was observed. The changes were independent of substantial improvements in glucose control.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00366301.

The effects of vildagliptin compared with metformin on vascular endothelial function and metabolic parameters: a randomized, controlled trial (Sapporo Athero-Incretin Study 3)

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitors may have protective effects in the early stage of atherosclerosis in patients with type 2 diabetes, although similar effects in advanced atherosclerosis were not shown in recent randomized placebo-controlled studies. Therefore, we investigated the efficacy of DPP-4 inhibitor on endothelial function and glycemic metabolism compared with high-dose metformin.

METHODS

In this multicenter, open-labeled, prospective, randomized, parallel-group comparison study, patients with type 2 diabetes treated with low-dose metformin (500-750 mg/day) were enrolled and randomly assigned to a vildagliptin, a DPP-4 inhibitor, add-on group (Vilda) or a double dose of metformin group (high Met) for 12 weeks. Flow-mediated dilation (FMD) and serum metabolic markers were assessed before and after treatment. In addition, glycemic control and metabolic parameters were also assessed.

RESULTS

Ninety-seven subjects (aged 58.7 ± 11.0 years; body mass index, 25.9 ± 4.4 kg/m2; HbA1c, 7.3 ± 0.5%; FMD, 5.8 ± 2.6%) were enrolled. Eight subjects dropped out by the end of the study. There were no significant differences between the two groups in baseline characteristics. After 12 weeks, HbA1c was significantly improved in the Vilda group compared with the high Met group (- 0.80 ± 0.38% vs. - 0.40 ± 0.47%, respectively; p < 0.01). However, there were no significant differences in FMD (- 0.51 [- 1.08-0.06]% vs. - 0.58 [- 1.20-0.04]%). Although the apolipoprotein B/apolipoprotein A1 ratio was significantly reduced in the Vilda group compared with baseline (0.66-0.62; p < 0.01), the change did not differ significantly between the two groups (- 0.04 vs. 0.00; p = 0.27). Adiponectin levels were significantly increased in the Vilda group compared with the high Met group (0.75 μg/mL vs. 0.01 μg/mL; p < 0.01).

CONCLUSIONS

Regardless of glycemic improvement, combination therapy of vildagliptin and metformin did not affect endothelial function but may exert favorable effects on adipokine levels and lipid profile in patients with type 2 diabetes without advanced atherosclerosis.

Epigenetic Changes in Diabetes and Cardiovascular Risk

Cardiovascular complications remain the leading causes of morbidity and premature mortality in patients with diabetes mellitus. Studies in humans and preclinical models demonstrate lasting gene expression changes in the vasculopathies initiated by previous exposure to high glucose concentrations and the associated overproduction of reactive oxygen species. The molecular signatures of chromatin architectures that sensitize the genome to these and other cardiometabolic risk factors of the diabetic milieu are increasingly implicated in the biological memory underlying cardiovascular complications and now widely considered as promising therapeutic targets. Atherosclerosis is a complex heterocellular disease where the contributing cell types possess distinct epigenomes shaping diverse gene expression. Although the extent that pathological chromatin changes can be manipulated in human cardiovascular disease remains to be established, the clinical applicability of epigenetic interventions will be greatly advanced by a deeper understanding of the cell type-specific roles played by writers, erasers, and readers of chromatin modifications in the diabetic vasculature. This review details a current perspective of epigenetic mechanisms of macrovascular disease in diabetes mellitus and highlights recent key descriptions of chromatinized changes associated with persistent gene expression in endothelial, smooth muscle, and circulating immune cells relevant to atherosclerosis. Furthermore, we discuss the challenges associated with pharmacological targeting of epigenetic networks to correct abnormal or deregulated gene expression as a strategy to alleviate the clinical burden of diabetic cardiovascular disease.

A Randomized Controlled Trial Comparing the Effects of Sitagliptin and Glimepiride on Endothelial Function and Metabolic Parameters: Sapporo Athero-Incretin Study 1 (SAIS1)

Objectives

The DPP-4 inhibitors are incretin-related drugs that improve hyperglycemia in a glucose-dependent manner and have been reported to exert favorable effects on atherosclerosis. However, it has not been fully elucidated whether DPP-4 inhibitors are able to improve endothelial function in patients with type 2 diabetes. Therefore, we investigated the efficacy of sitagliptin, a DPP-4 inhibitor, on endothelial function and glycemic metabolism compared with that of the sulfonylurea glimepiride.

Materials and Methods

In this multicenter, prospective, randomized parallel-group comparison study, 103 outpatients with type 2 diabetes (aged 59.9 ± 9.9 years with HbA1c levels of 7.5 ± 0.4%) with dietary cure only and/or current metformin treatment were enrolled and randomly assigned to receive sitagliptin or glimepiride therapy once daily for 26 weeks. Flow-mediated dilation (FMD), a comprehensive panel of hemodynamic parameters (Task Force^® Monitor), and serum metabolic markers were assessed before and after the treatment.

Results

During the study period, no statistically significant change in %FMD was seen in both groups (sitagliptin, 5.6 to 5.6%; glimepiride, 5.6 to 6.0%). Secretory units of islets in transplantation, TNF-α, adiponectin and biological antioxidant potential significantly improved in the sitagliptin group, and superoxide dismutase also tended to improve in the sitagliptin group, while improvements in HbA1c levels were similar between groups. Cardiac index, blood pressure and most other metabolic parameters were not different.

Conclusions

Regardless of glycemic improvement, early sitagliptin therapy did not affect endothelial function but may provide favorable effects on beta-cell function and on inflammatory and oxidative stress in patients with type 2 diabetes without advanced atherosclerosis.

Trial Registration

UMIN Clinical Trials Registry System UMIN 000004955

The Cardiovascular Biology of Glucagon-like Peptide-1

Glucagon-like peptide-1, produced predominantly in enteroendocrine cells, controls glucose metabolism and energy homeostasis through regulation of islet hormone secretion, gastrointestinal motility, and food intake, enabling development of GLP-1 receptor (GLP-1R) agonists for the treatment of diabetes and obesity. GLP-1 also acts on the immune system to suppress inflammation, and GLP-1R signaling in multiple tissues impacts cardiovascular function in health and disease. Here we review how GLP-1 and clinically approved GLP-1R agonists engage mechanisms that influence the risk of developing cardiovascular disease. We discuss how GLP-1R agonists modify inflammation, cardiovascular physiology, and pathophysiology in normal and diabetic animals through direct and indirect mechanisms and review human studies illustrating mechanisms linking GLP-1R signaling to modification of the cardiovascular complications of diabetes. The risks and benefits of GLP-1R agonists are updated in light of recent data suggesting that GLP-1R agonists favorably modify outcomes in diabetic subjects at high risk for cardiovascular events.

Cardiovascular safety for once-weekly dulaglutide in type 2 diabetes: a pre-specified meta-analysis of prospectively adjudicated cardiovascular events

BACKGROUND

Patients with type 2 diabetes (T2D) have a substantial increased risk for cardiovascular (CV) disease and associated mortality than those without diabetes. Dulaglutide is a once-weekly glucagon-like peptide-1 receptor agonist that is approved for treatment of T2D.

METHODS

This meta-analysis evaluates the CV risk in patients with T2D treated with dulaglutide in 9 randomized safety and efficacy trials. Mean (median) treatment duration was 333 (358) days. Reported CV events were independently adjudicated by a treatment-blinded clinical endpoint committee. The primary measure was a 4-component major adverse CV event (4-component MACE) composite endpoint of death due to CV causes, nonfatal myocardial infarction (MI), nonfatal stroke, or hospitalization for unstable angina. Additional pre-specified endpoints included adjudicated coronary revascularizations, hospitalization for heart failure, and all-cause mortality. A Cox proportional hazards regression model (stratified by study) was used to estimate the hazard ratio (HR) and confidence interval (CI). Tests of treatment effects for the primary endpoint were conducted at a 2-sided alpha level of 0.0198 and a corresponding 98.02 % CI was calculated. Statistical heterogeneity between the strata (studies) was tested by including in the Cox model an interaction term between treatment and strata.

RESULTS

The analysis included 6010 randomized patients [dulaglutide: 3885; comparator therapy (active or placebo): 2125]; cumulative exposure to dulaglutide or comparator therapy was 3941 and 2223 patient-years, respectively. The demographic and baseline CV disease characteristics were similar across groups. Twenty-six (0.67 %) patients in the dulaglutide group versus 25 (1.18 %) in the comparator group experienced a primary 4-component MACE (HR 0.57; adjusted 98.02 % CI 0.30, 1.10). Results for the 3-component MACE (composite endpoint of death due to CV causes, nonfatal MI or stroke), 6-component MACE (composite endpoint of death due to CV causes, nonfatal MI or stroke, hospitalization for unstable angina or heart failure, or coronary revascularizations) and all-cause mortality were consistent with the primary analysis (HR < 1.0 for all).

CONCLUSIONS

These results suggest that dulaglutide does not increase the risk of major CV events in T2D patients. The ongoing CV outcomes study, Researching CV Events with a Weekly Incretin in Diabetes (REWIND), will further assess CV safety of dulaglutide.