Cardiovascular Actions and Clinical Outcomes With Glucagon-Like Peptide-1 Receptor Agonists and Dipeptidyl Peptidase-4 Inhibitors

Cardiovascular effects of antiobesity drugs: are the new medicines all the same?

Waiting for a definite answer from well-designed randomized prospective clinical trials, the impact of the new antiobesity drugs -liraglutide, bupropion/naltrexone, phentermine/topiramate and lorcaserin- on cardiovascular outcomes remains uncertain. What has been learned from previous experience with older medicines is that antiobesity drugs may influence cardiovascular health not only causing weight reduction but also through direct actions on the cardiovascular system. Therefore, in the present review, we examine what is known, mainly from preclinical investigations, about the cardiovascular pharmacology of the new antiobesity medicines with the aim of highlighting potential mechanistic differences. We will show that the two active substances of the bupropion/naltrexone combination both exert beneficial and unwanted cardiovascular effects. Indeed, bupropion exerts anti-inflammatory effects but at the same time it does increase heart rate and blood pressure by potentiating catecholaminergic neurotransmission, whereas naltrexone reduces TLR4-dependent inflammation and has potential protective effects in stroke but also impairs cardiac adaption to ischemia and the beneficial opioid protective effects mediated in the endothelium. On the contrary, with the only exception of a small increase in heat rate, liraglutide only exerts favorable cardiovascular effects by protecting myocardium and brain from ischemic damage, improving heart contractility, lowering blood pressure and reducing atherogenesis. As far as the phentermine/topiramate combination is concerned, no direct cardiovascular beneficial effect is expected for phentermine (as this drug is an amphetamine derivative), whereas topiramate may exert cardioprotective and neuroprotective effects in ischemia and anti-inflammatory and antiatherogenic actions. Finally, lorcaserin, a selective 5HT_2C receptor agonist, does not seem to exert significant direct effects on the cardiovascular system though at very high concentrations this drug may also interact with other serotonin receptor subtypes and exert unwanted cardiovascular effects. In conclusion, the final effect of the new antiobesity drugs on cardiovascular outcomes will be a balance between possible (but still unproved) beneficial effects of weight loss and "mixed" weight-independent drug-specific effects. Therefore comparative studies will be required to establish which one of the new medicines is more appropriate in patients with specific cardiovascular diseases.

Potential of Glucagon-Like Peptide 1 as a Regulator of Impaired Cholesterol Metabolism in the Brain

Cerebral vascular diseases are the most common high-mortality diseases worldwide. Their onset and development are associated with glycemic imbalance, genetic background, alteration of atherosclerotic factors, severe inflammation, and abnormal cholesterol metabolism. Recently, the gut-brain axis has been highlighted as the key to the solution for cerebral vessel dysfunction in view of cholesterol metabolism and systemic lipid circulation. In particular, glucagon-like peptide 1 (GLP-1) is a cardinal hormone that regulates blood vessel function and cholesterol homeostasis and acts as a critical messenger between the brain and gut. GLP-1 plays a systemic regulatory role in cholesterol homeostasis and blood vessel function in various organs through blood vessels. Even though GLP-1 has potential in the treatment and prevention of cerebral vascular diseases, the importance of and relation between GLP-1 and cerebral vascular diseases are not fully understood. Herein, we review recent findings on the functions of GLP-1 in cerebral blood vessels in association with cholesterol metabolism.

Exogenous supplement of glucagon like peptide-1 protects the heart against aortic banding induced myocardial fibrosis and dysfunction through inhibiting mTOR/p70S6K signaling and promoting autophagy

Mammalian target of rapamycin (mTOR) and a ribosomal protein S6 kinase (p70S6K) mediate tissue fibrosis and negatively regulate autophagy. This study aims to investigate whether glucagon-like peptide-1 (GLP-1) analog liraglutide protects the heart against aortic banding-induced cardiac fibrosis and dysfunction through inhibiting mTOR/p70S6K signaling and promoting autophagy activity. Male SD rats were randomly divided into four groups (n = 6/each group): sham operated control; abdominal aortic constriction (AAC); liraglutide treatment during AAC (0.3 mg/kg, injected subcutaneously twice daily); rapamycin treatment during AAC (0.2 mg/kg/day, administered by gastric gavage). Relative to the animals with AAC on week 16, liraglutide treatment significantly reduced heart/body weight ratio, inhibited cardiomyocyte hypertrophy, and augmented plasma GLP-1 level and tissue GLP-1 receptor expression. Phosphorylation of mTOR/p70S6K, populations of myofibroblasts and synthesis of collagen I/III in the myocardium were simultaneously inhibited. Furthermore, autophagy regulating proteins: LC3-II/LC3-I ratio and Beclin-1 were upregulated, and p62 was downregulated by liraglutide. Compared with liraglutide group, treatment with rapamycin, a specific inhibitor of mTOR, compatibly augmented GLP-1 receptor level, inhibited phosphorylation of mTOR/p70S6K and expression of p62 as well as increased level of LC3-II/LC3-I ratio and Beclin-1, suggesting that there is an interaction between GLP-1 and mTOR/p70S6K signaling in the regulation of autophagy. In line with these modifications, treatment with liraglutide and rapamycin significantly reduced perivascular/interstitial fibrosis, and preserved systolic/diastolic function. These results suggest that the inhibitory effects of liraglutide on cardiac fibrosis and dysfunction are potentially mediated by inhibiting mTOR/p70S6K signaling and enhancing autophagy activity.

A randomized, open-label, active comparator trial assessing the effects of 26 weeks of liraglutide or sitagliptin on cardiovascular function in young obese adults with type 2 diabetes

AIM

To compare the effects of a glucagon-like peptide-1 receptor agonist and a dipeptidyl peptidase-4 inhibitor on magnetic resonance imaging-derived measures of cardiovascular function.

MATERIALS AND METHODS

In a prospective, randomized, open-label, blinded endpoint trial liraglutide (1.8 mg) and sitagliptin (100 mg) were compared in asymptomatic, non-insulin treated young (aged 18-50 years) adults with obesity and type 2 diabetes. The primary outcome was difference in circumferential peak early diastolic strain rate change (PEDSR), a biomarker of cardiac diastolic dysfunction 26 weeks after randomization. Secondary outcomes included other indices of cardiac structure and function, HbA1c and body weight.

RESULTS

Seventy-six participants were randomized (54% female, mean ± SD age 44 ± 6 years, diabetes duration 4.4 years, body mass index 35.3 ± 6.1 kg m^-2 ), of whom 65% had ≥1 cardiovascular risk factor. Sixty-one participants had primary outcome data available. There were no statistically significant between-group differences (intention-to-treat; mean [95% confidence interval]) in PEDSR change (-0.01 [-0.07, +0.06] s^-1 ), left ventricular ejection fraction (-1.98 [-4.90, +0.94]%), left ventricular mass (+1.14 [-5.23, +7.50] g) or aortic distensibility (-0.35 [-0.98, +0.28] mmHg^-1  × 10^-3 ) after 26 weeks. Reductions in HbA1c (-4.57 [-9.10, -0.37] mmol mol^-1 ) and body weight (-3.88 [-5.74, -2.01] kg) were greater with liraglutide.

CONCLUSION

There were no differences in cardiovascular structure or function after short-term use of liraglutide and sitagliptin in younger adults with obesity and type 2 diabetes. Longer studies in patients with more severe cardiac dysfunction may be necessary before definitive conclusions can be made about putative pleiotropic properties of incretin-based therapies.

[New oral antidiabetic drugs]

A paradigm change in the treatment of type 2 diabetes has recently emerged due to the introduction of new oral antidiabetic agents. Cardiovascular endpoint studies confirmed the safety of dipeptidyl peptidase 4 (DPP-4) inhibitors and a cardiovascular protective effect for glucagon-like peptide 1 (GLP-1) receptor agonists and sodium-glucose linked transporter 2 (SGLT-2) inhibitors. Furthermore, SGLT‑2 inhibitors reduce the risk for heart failure and have a renoprotective effect. These studies led to changes in clinical recommendations and guidelines. In patients with high or very high cardiorenal risk, SGLT‑2 inhibitors or GLP‑1 receptor agonists are recommended for risk protection independent of HbA1c values, with existing or high risk for chronic heart failure SGLT‑2 inhibitors are the preferred choice. Therefore, the choice of antidiabetic treatment strategy is no longer determined by the level of glycosylated hemoglobin (HbA1c) alone but particularly by the cardiorenal risk of the individual patient.

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.

Cardiovascular Risk Reduction With Liraglutide: An Exploratory Mediation Analysis of the LEADER Trial

OBJECTIVE

The Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) trial (ClinicalTrials.gov reg. no. NCT01179048) demonstrated a reduced risk of cardiovascular (CV) events for patients with type 2 diabetes who received the glucagon-like peptide 1 receptor agonist liraglutide versus placebo. The mechanisms behind this CV benefit remain unclear. We aimed to identify potential mediators for the CV benefit observed with liraglutide in the LEADER trial.

RESEARCH DESIGN AND METHODS

We performed exploratory analyses to identify potential mediators of the effect of liraglutide on major adverse CV events (MACE; composite of CV death, nonfatal myocardial infarction, or nonfatal stroke) from the following candidates: glycated hemoglobin (HbA_1c), body weight, urinary albumin-to-creatinine ratio (UACR), confirmed hypoglycemia, sulfonylurea use, insulin use, systolic blood pressure, and LDL cholesterol. These candidates were selected as CV risk factors on which liraglutide had an effect in LEADER such that a reduction in CV risk might result. We used two methods based on a Cox proportional hazards model and the new Vansteelandt method designed to use all available information from the mediator and to control for confounding factors.

RESULTS

Analyses using the Cox methods and Vansteelandt method indicated potential mediation by HbA_1c (up to 41% and 83% mediation, respectively) and UACR (up to 29% and 33% mediation, respectively) on the effect of liraglutide on MACE. Mediation effects were small for other candidates.

CONCLUSIONS

These analyses identify HbA_1c and, to a lesser extent, UACR as potential mediators of the CV effects of liraglutide. Whether either is a marker of an unmeasured factor or a true mediator remains a key question that invites further investigation.

Downregulation of the GLP-1/CREB/adiponectin pathway is partially responsible for diabetes-induced dysregulated vascular tone and VSMC dysfunction

BACKGROUND

The dysfunction of vasculature is observed in diabetes and might be responsible for the increased incidence of vascular events. Previous studies indicated that supplementation of GLP-1 analogues is beneficial to the cardiovascular functions in diabetic patients, but the mechanisms are not clear.

METHODS

A type 1 diabetic model was constructed. Vascular constrictions were measured using wire myograph. Western blotting and quantitative PCR were adopted to analyze the expression profiles of key molecules. Mitochondrial functions were analyzed in both vascular tissues or vascular smooth muscle cells (VSMCs). Dual-luciferase reporter assay was used to investigate the mechanism of adiponectin regulation.

RESULTS

In this study, abnormal vascular hypertrophy and increased vascular tones were observed in both diabetic patients and animals. ROS productions were increased in vessels and VSMCs from diabetic patients and animals, and the ROS scavenger mitoTEMPO partially attenuated the abnormal vascular tones and hypertension. In addition, decreased GLP-1 levels were observed, while GLP-1 supplementation improved the mitochondrial functions and vascular tones. Furthermore, it was shown that GLP-1 supplementation enhanced adiponectin expressions, while adiponectin facilitated the phosphorylation of AMPK and Sirt1 expressions. Also, CREB phosphorylation was enhanced upon GLP-1 supplementation and promoted the transcriptions of adiponectin. Finally, CREB inhibition partially attenuated the effects of GLP-1 on mitochondrial functions and adiponectin expressions.

CONCLUSION

GLP-1 downregulation might be an important mechanism of abnormal mitochondrial function and vascular tone in diabetes. Targeting GLP-1/CREB/adiponectin axis might become a promising therapeutic strategy in alleviating diabetes-related cardiovascular dysfunctions.

Major cardiovascular events, heart failure, and atrial fibrillation in patients treated with glucagon-like peptide-1 receptor agonists: An updated meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Glucagon-like Peptide 1 Receptor Agonists (GLP1-RA) has been associated with a reduction of major cardiovascular events (MACE) and mortality on the basis of the results of cardiovascular outcome trials (CVOT). Several meta-analyses on this issue have been recently published; however, they were all restricted to CVOT, with the exclusion of all studies designed for other endpoints; moreover, other cardiovascular endpoints, such as atrial fibrillation and heart failure have not been fully explored.

METHODS AND RESULTS

A Medline search for GLP-1 receptor agonists (exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, or semaglutide) was performed, collecting all randomized clinical trials with a duration ≥52 weeks, enrolling patients with type 2 diabetes, and comparing a GLP-1 receptor agonist with placebo or any other non-GLP-1 receptor agonist drug. We included 43 trials, enrolling 63,134 patients. A significant reduction of MACE (MH-OR 0.87 [0.83, 0.92]), all-cause mortality (MH-OR 0.89 [0.83, 0.96]), and a nonstatistical trend toward reduction of heart failure (MH-OR 0.93 [0.85, 1.01]) was observed - GLP1-RA did not increase the risk of atrial fibrillation (MH-OR 0.94 [0.84, 1.04]).

CONCLUSION

The present meta-analysis confirms the favorable effects of glucagon-like peptide-1 receptor agonists on major cardiovascular events, cardiovascular and all-cause mortality, stroke, and possibly myocardial infarction. Conversely, the effects on heart failure remain uncertain. Available data on atrial fibrillation seems to exclude any major safety issues in this respect.

REGISTRATION NUMBER (PROSPERO)

CRD42018115577.

The treament of hyperglycemia in acute ischemic stroke with incretin-based drugs

Stroke is a major cause of mortality and morbidity worldwide. Considerable experimental and clinical evidence suggests that both diabetes mellitus (DM) and post-stroke hyperglycemia are associated with increased mortality rate and worsened clinical conditions in acute ischemic stroke (AIS) patients. Insulin treatment does not seem to provide convincing benefits for these patients, therefore prompting a change of strategy. The selective agonists of Glucagon-Like Peptide-1 Receptors (GLP-1Ras) and the Inhibitors of Dipeptidyl Peptidase-IV (DPP-IVIs, gliptins) are two newer classes of glucose-lowering drugs used for the treatment of DM. This review examines in detail the rationale for their development and the physicochemical, pharmacokinetic and pharmacodynamic properties and clinical activities. Emphasis will be placed on their neuroprotective effects at cellular and molecular levels in experimental models of acute cerebral ischemia. In perspective, an adequate basis does exist for a novel therapeutic approach to hyperglycemia in AIS patients through the additive treatment with GLP-1Ras plus DPP-IVIs.

Generalizability of sodium-glucose co-transporter-2 inhibitors cardiovascular outcome trials to the type 2 diabetes population: a systematic review and meta-analysis

Background

Cardiovascular outcome trials of sodium-glucose co-transporter-2 inhibitors (SGLT2i CVOTs) found the agents to be associated with clinical benefits in terms of cardiovascular and renal outcomes. We performed a meta-analysis to assess and compare the overall prevalence of eligibility for the enrollment criteria of CANVAS, DECLARE-TIMI 58, EMPA-REG OUTCOME, and VERTIS-CV among unselected patients with type 2 diabetes.

Methods

This meta-analysis was registered in PROSPERO (CRD42020172032). PubMed, CENTRAL, Scopus and Web of Science were researched in March 2020. Studies evaluating the prevalence of eligibility for each SGLT2i CVOT were selected. Endpoints were estimated using a random-effects model.

Results

Five studies, evaluating 1,703,519 patients with type 2 diabetes, were included. Overall, the prevalence of eligible patients according to the enrollment criteria of CANVAS, DECLARE-TIMI 58, EMPA-REG OUTCOME, and VERTIS-CV was 36.4%, 49.5%, 17.0% and 19.0%, respectively. In head-to-head comparisons, DECLARE-TIMI 58 was associated with the highest odds of eligibility (1.74 versus CANVAS, 5.15 versus EMPA-REG OUTCOME and 4.81 versus VERTIS-CV), followed by CANVAS and EMPA-REG OUTCOME/VERTIS-CV. A high heterogeneity was found for all the outcomes.

Conclusions

The present review showed that a considerable number of patients counseled in clinical practice could have been eligible for SGLT2i CVOTs. Particularly, dapagliflozin was shown to be the SGLT2i with the largest generalizability of findings from its CVOT according to the odds ratio of eligibility for the enrollment criteria among unselected patients with type 2 diabetes. Further country- or region-specific studies are needed to confirm the applicability of our results.

Insights into incretin-based therapies for treatment of diabetic dyslipidemia

Derangements in triglyceride and cholesterol metabolism (dyslipidemia) are major risk factors for the development of cardiovascular diseases in obese and type-2 diabetic (T2D) patients. An emerging class of glucagon-like peptide-1 (GLP-1) analogues and next generation peptide dual-agonists such as GLP-1/glucagon or GLP-1/GIP could provide effective therapeutic options for T2D patients. In addition to their role in glucose and energy homeostasis, GLP-1, GIP and glucagon serve as regulators of lipid metabolism. This review summarizes the current knowledge in GLP-1, glucagon and GIP effects on lipid and lipoprotein metabolism and frames the emerging therapeutic benefits of GLP-1 analogs and GLP-1-based multiagonists as add-on treatment options for diabetes associated dyslipidemia.

Treatment of Obesity in Mitigating Metabolic Risk

Through diverse mechanisms, obesity contributes to worsened cardiometabolic health and increases rates of cardiovascular events. Effective treatment of obesity is necessary to reduce the associated burdens of diabetes mellitus, cardiovascular disease, and death. Despite increasing cardiovascular outcome data on obesity interventions, only a small fraction of the population with obesity are optimally treated. This is a primary impetus for this article in which we describe the typical weight loss, as well as the associated impact on both traditional and novel cardiovascular disease risk factors, provided by the 4 primary modalities for obtaining weight loss in obesity-dietary modification, increasing physical activity, pharmacotherapy, and surgery. We also attempt to highlight instances where changes in metabolic risk are relatively specific to particular interventions and appear at least somewhat independent of weight loss. Finally, we suggest important areas for further research to reduce and prevent adverse cardiovascular consequences due to obesity.

Combining Glucagon-Like Peptide 1 Receptor Agonists and Sodium-Glucose Cotransporter 2 Inhibitors to Target Multiple Organ Defects in Type 2 Diabetes

Long-term risks of macro- and microvascular complications may be reduced in people with type 2 diabetes who achieve early and sustained glycemic control. Delays in attaining A1C goals are associated with poor long-term cardiovascular (CV) outcomes. Glucagon-like peptide 1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors are glucose-lowering therapies that act through complementary mechanisms of action with regard to the pathophysiologic defects of type 2 diabetes. Trials of agents in both drug classes have demonstrated improvements in CV and renal outcomes. This review discusses the rationale for combination therapy with a GLP-1 receptor agonist and an SGLT2 inhibitor, including early initiation of this combination in newly diagnosed patients. This combination may lead to timely glycemic control and potentially additive CV and renal benefits. Clinical studies of the combination have shown partially additive effects on A1C reduction, additive effects on weight reduction, and potentially synergistic effects on blood pressure reduction. Long-term studies are needed to determine whether the combination provides an additional effect on CV and renal outcomes compared with agents from either drug class when used alone.

Metabolically Healthy Obesity

Obesity contributes to reduced life expectancy, impaired quality of life, and disabilities, mainly in those individuals who develop cardiovascular diseases, type 2 diabetes, osteoarthritis, and cancer. However, there is a large variation in the individual risk to developing obesity-associated comorbid diseases that cannot simply be explained by the extent of adiposity. Observations that a proportion of individuals with obesity have a significantly lower risk for cardiometabolic abnormalities led to the concept of metabolically healthy obesity (MHO). Although there is no clear definition, normal glucose and lipid metabolism parameters-in addition to the absence of hypertension-usually serve as criteria to diagnose MHO. Biological mechanisms underlying MHO lower amounts of ectopic fat (visceral and liver), and higher leg fat deposition, expandability of subcutaneous adipose tissue, preserved insulin sensitivity, and beta-cell function as well as better cardiorespiratory fitness compared to unhealthy obesity. Whereas the absence of metabolic abnormalities may reduce the risk of type 2 diabetes and cardiovascular diseases in metabolically healthy individuals compared to unhealthy individuals with obesity, it is still higher in comparison with healthy lean individuals. In addition, MHO seems to be a transient phenotype further justifying therapeutic weight loss attempts-even in this subgroup-which might not benefit from reducing body weight to the same extent as patients with unhealthy obesity. Metabolically healthy obesity represents a model to study mechanisms linking obesity to cardiometabolic complications. Metabolically healthy obesity should not be considered a safe condition, which does not require obesity treatment, but may guide decision-making for a personalized and risk-stratified obesity treatment.

Exenatide once weekly slows gastric emptying of solids and liquids in healthy, overweight people at steady-state concentrations

AIMS

To evaluate the effects of 8 weeks' administration of exenatide (EXE) once weekly on gastric emptying of solids and liquids (using the "gold standard" technique, scintigraphy), glucose absorption and postprandial glycaemia in healthy people.

MATERIAL AND METHODS

A total of 32 healthy participants were randomized to receive either EXE once weekly (2 mg/wk subcutaneously; six men, 10 women, mean age 59.9 ± 0.9 years, mean body mass index [BMI] 29.6 ± 0.6 kg/m² ) or matching placebo (PBO; six men, 10 women, mean age 60.6 ± 1.2 years, mean BMI 29.5 ± 1.0 kg/m² ) for 8 weeks. Gastric emptying, nausea (visual analogue scale), and plasma glucose, insulin, C-peptide and glucagon were measured for 120 min after a solid/liquid meal, comprising 100 g ground beef (radiolabelled with 20 MBq ^99m Tc-sulphur colloid) and 150 mL 10% glucose (radiolabelled with 7 MBq ⁶⁷ Ga-EDTA), and containing 5 g 3-O-methyl-glucose (3-OMG) as a marker of glucose absorption, at baseline and after 8 weeks' treatment.

RESULTS

The study treatments were well tolerated. Scores for nausea were consistently low, with no difference between the EXE once weekly and PBO groups. EXE once weekly slowed gastric emptying of solids (area under the curve [AUC]_0-120min : P < 0.05) and liquids (AUC_0-120min : P = 0.01) substantially, and attenuated glucose absorption (3-OMG incremental AUC [iAUC]_0-30min : P = 0.001) and the postprandial rise in plasma glucose (iAUC_0-30min : P = 0.008). Plasma glucagon at 2 h was reduced by EXE once weekly (P = 0.001). The magnitude of the reduction in plasma glucose at t = 30 min from baseline to 8 weeks with EXE once weekly was related inversely to the 50% emptying time of the glucose drink (r = -0.55, P = 0.03).

CONCLUSIONS

In healthy participants, 8 weeks' administration of the "long-acting" glucagon-like peptide-1 receptor agonist EXE, slowed gastric emptying of solids and liquids substantially, with consequent reductions in glucose absorption and postprandial glycaemia.

Effects of Glucagon-Like Peptide-1 Receptor Agonists, Sodium-Glucose Cotransporter-2 Inhibitors, and Their Combination on Endothelial Glycocalyx, Arterial Function, and Myocardial Work Index in Patients With Type 2 Diabetes Mellitus After 12-Month Treatment

Background We investigated the effects of insulin, glucagon-like peptide-1 receptor agonists (GLP-1RA), sodium-glucose cotransporter-2 inhibitors (SGLT-2i), and their combination on vascular and cardiac function of patients with type 2 diabetes mellitus. Methods and Results A total of 160 patients with type 2 diabetes mellitus were randomized to insulin (n=40), liraglutide (n=40), empagliflozin (n=40), or their combination (GLP-1RA+SGLT-2i) (n=40) as add-on to metformin. We measured at baseline and 4 and 12 months posttreatment: (a) perfused boundary region of the sublingual arterial microvessels (marker of endothelial glycocalyx thickness), (b) pulse wave velocity (PWV) and central systolic blood pressure, (c) global left ventricular longitudinal, circumferential, and radial strain, (d) myocardial work index (global work index) derived by pressure-myocardial strain loops using speckle tracking imaging. Twelve months posttreatment, all patients improved perfused boundary region, PWV, global longitudinal strain, global circumferential strain, and global radial strain (P<0.05). GLP-1RA, SGLT-2i, and their combination showed a greater reduction of perfused boundary region, PWV, and central systolic blood pressure than insulin, despite a similar glycosylated hemoglobin reduction (P<0.05). GLP-1RA or GLP-1RA+SGLT-2i provided a greater increase of global work index (12.7% and 17.4%) compared with insulin or SGLT-2i (3.1% and 2%). SGLT-2i or GLP-1RA and SGLT-2i showed a greater decrease of PWV (10.1% and 13%) and central and brachial systolic blood pressure than insulin or GLP-1RA (PWV, 3.6% and 8.6%) (P<0.05 for all comparisons). The dual therapy showed the greatest effect on measured markers in patients with left ventricular ejection fraction <55% (P<0.05). Conclusions Twelve-month treatment with GLP-1RA, SGLT-2i, and their combination showed a greater improvement of vascular markers and effective cardiac work than insulin treatment in type 2 diabetes mellitus. The combined therapy as second line was superior to either insulin or GLP-1RA and SGLT-2i separately. Registration URL: https://www.clini​caltr​ials.gov. Unique identifier: NCT03878706.

Effects of dipeptidyl peptidase 4 inhibition on inflammation in atherosclerosis: A 18F-fluorodeoxyglucose study of a mouse model of atherosclerosis and type 2 diabetes

BACKGROUND AND AIMS

Dipeptidyl peptidase 4 (DPP-4) inhibitors have anti-inflammatory and atheroprotective effects. We evaluated the effects of the DPP-4 inhibitor linagliptin on atherosclerotic plaque and hepatic inflammation using histology and 2-deoxy-2-[¹⁸F]-fluoro-d-glucose (¹⁸F-FDG), a positron emission tomography tracer of inflammation, in a mouse model of hypercholesterolemia and type 2 diabetes.

METHODS

Igf2/Ldlr^-/-Apob^100/100 mice were fed a high-fat diet (HFD) for 8 weeks and then randomly allocated to receive HFD (n = 14), or HFD with added linagliptin (n = 15) for additional 12 weeks. Five mice fed a chow diet were studied as an additional control. At the end of the study, glucose tolerance, aortic and liver uptake of ¹⁸F-FDG, and histology were studied.

RESULTS

Mice in linagliptin and HFD groups had similar fasting glucose concentrations, but linagliptin improved glucose tolerance. Aortas of linagliptin and HFD groups showed advanced atherosclerotic plaques with no difference in the mean intima-to-media ratio or number of macrophages in the plaques. Autoradiography showed similar ¹⁸F-FDG uptake by atherosclerotic plaques in linagliptin and HFD groups (plaque-to-wall ratio: 1.7 ± 0.25 vs. 1.6 ± 0.21; p = 0.24). In the liver, linagliptin reduced the histologic inflammation score but had no effect on ¹⁸F-FDG uptake. Compared with chow diet, uptake of ¹⁸F-FDG was similar in the aorta, but higher in the liver after HFD.

CONCLUSIONS

Linagliptin therapy improved glucose tolerance and reduced hepatic inflammation but had no effect on plaque burden or atherosclerotic inflammation, as determined by histology and ¹⁸F-FDG uptake, in atherosclerotic mice with type 2 diabetes.

Leveraging the Gut to Treat Metabolic Disease

25 years ago, the future of treating obesity and diabetes focused on end organs known to be involved in energy balance and glucose regulation, including the brain, muscle, adipose tissue, and pancreas. Today, the most effective therapies are focused around the gut. This includes surgical options, such as vertical sleeve gastrectomy and Roux-en-Y gastric bypass, that can produce sustained weight loss and diabetes remission but also extends to pharmacological treatments that simulate or amplify various signals that come from the gut. The purpose of this Review is to discuss the wealth of approaches currently under development that seek to further leverage the gut as a source of novel therapeutic opportunities with the hope that we can achieve the effects of surgical interventions with less invasive and more scalable solutions.

Invited review. Series: Implications of the recent CVOTs in type 2 diabetes: Which patients for GLP-1RA or SGLT-2 inhibitor?

Large cardiovascular outcome trials (CVOTs) have lent support to a cardiovascular protection with the use of SGLT2-inhibitors (SGLT2is) and GLP1-Receptor Agonists (GLP1-RAs) in subjects with type 2 diabetes. These two classes of novel glucose lowering agents have been shown to have a similar effect on the risk reduction of Major Adverse Cardiovascular Events (MACE: nonfatal myocardial infarction, nonfatal stroke, cardiovascular mortality). Nonetheless, they may not be simply interchangeable. Rather, careful evaluation of all the results of CVOTs leads identification of different effects that may allow profiling of the ideal individuals with T2DM who may benefit most from the use of one or the other class of agents. These differences include effect on heart failure, stroke and diabetic kidney disease that have prompt recent guidelines and recommendation for the treatment of type 2 diabetes to suggest the preferential use of SGLT2is in those with evidence of heart failure and impaired kidney function, while both SGLT2i and GLP1-RAs with proven effect could be use in those with prevalent atherosclerotic cardiovascular disease. This review discusses all these elements of differentiation along with others that in the future may help establishing the best cardiorenal benefit for individuals with T2DM.

GLP-1 Receptor Agonists and Diabetic Kidney Disease: A Call of Attention to Nephrologists

Type 2 diabetes mellitus (T2DM) represents the main cause of chronic kidney disease (CKD) and end-stage renal disease (ESKD), and diabetic kidney disease (DKD) is a major cause of morbidity and mortality in diabetes. Despite advances in the nephroprotective treatment of T2DM, DKD remains the most common complication, driving the need for renal replacement therapies (RRT) worldwide, and its incidence is increasing. Until recently, prevention of DKD progression was based around strict blood pressure (BP) control, using renin-angiotensin system blockers that simultaneously reduce BP and proteinuria, adequate glycemic control and control of cardiovascular risk factors. Glucagon-like peptide-1 receptor agonists (GLP-1RA) are a new class of anti-hyperglycemic drugs shown to improve cardiovascular and renal events in DKD. In this regard, GLP-1RA offer the potential for adequate glycemic control in multiple stages of DKD without an increased risk of hypoglycemia, preventing the onset of macroalbuminuria and slowing the decline of glomerular filtration rate (GFR) in diabetic patients, also bringing additional benefit in weight reduction, cardiovascular and other kidney outcomes. Results from ongoing trials are pending to assess the impact of GLP-1RA treatments on primary kidney endpoints in DKD.

Deletion of Gpr27 in vivo reduces insulin mRNA but does not result in diabetes

Gpr27 is a highly conserved, orphan G protein coupled receptor (GPCR) previously implicated in pancreatic beta cell insulin transcription and glucose-stimulated insulin secretion in vitro. Here, we characterize a whole-body mouse knockout of Gpr27. Gpr27 knockout mice were born at expected Mendelian ratios and exhibited no gross abnormalities. Insulin and Pdx1 mRNA in Gpr27 knockout islets were reduced by 30%, but this did not translate to a reduction in islet insulin content or beta cell mass. Gpr27 knockout mice exhibited slightly worsened glucose tolerance with lower plasma insulin levels while maintaining similar insulin tolerance. Unexpectedly, Gpr27 deletion reduced expression of Eif4e3, a neighboring gene, likely by deleting transcription start sites on the anti-sense strand of the Gpr27 coding exon. Our data confirm that loss of Gpr27 reduces insulin mRNA in vivo but has only minor effects on glucose tolerance.

Abnormal Ca2+ handling contributes to the impairment of aortic smooth muscle contractility in Zucker diabetic fatty rats

Vascular dysfunction is a common pathological basis for complications in individuals affected by diabetes. Previous studies have established that endothelial dysfunction is the primary contributor to vascular complications in type 2 diabetes (T2DM). However, the role of vascular smooth muscle cells (VSMCs) in vascular complications associated with T2DM is still not completely understood. The aim of this study is to explore the potential mechanisms associated with Ca²⁺ handling dysfunction and how this dysfunction contributes to diabetic vascular smooth muscle impairment. The results indicated that endothelium-dependent vasodilation was impaired in diabetic aortae, but endothelium-independent vasodilation was not altered. Various vasoconstrictors such as phenylephrine, U46619 and 5-HT could induce vasoconstriction in a concentration-dependent manner, such that the dose-response curve was parallel shifted to the right in diabetic aortae, compared to the control. Vasoconstrictions mediated by L-type calcium (Cav1.2) channels were attenuated in diabetic aortae, but effects mediated by store-operated calcium (SOC) channels were enhanced. Intracellular Ca²⁺ concentration ([Ca²⁺]_i) in VSMCs was detected by Fluo-4 calcium fluorescent probes, and demonstrated that SOC-mediated Ca²⁺ entry was increased in diabetic VSMCs. VSMC-specific knockout of STIM1 genes decreased SOC-mediated and phenylephrine-induced vasoconstrictive response in mice aortae. Additionally, Orai1 expression was up-regulated, Cav1.2 expression was downregulated, and the phenotypic transformation of diabetic VSMCs was determined in diabetic aortae. The overexpression of Orai1 markedly promoted the OPN expression of VSMCs, whereas SKF96365 (SOC channel blocker) reversed the phenotypic transformation of diabetic VSMCs. Our results demonstrated that the vasoconstriction response of aortic smooth muscle was weakened in type 2 diabetic rats, which was related to the downregulation of the Cav1.2 channel and the up-regulation of the SOC channel signaling pathway.

Dipeptidyl Peptidase-4 at the Interface Between Inflammation and Metabolism

Dipeptidyl peptidase-4 (DPP4) is a serine protease that rapidly inactivates the incretin peptides, glucagon-like peptide-1, and glucose-dependent insulinotropic polypeptide to modulate postprandial islet hormone secretion and glycemia. Dipeptidyl peptidase-4 also has nonglycemic effects by controlling the progression of inflammation, which may be mediated more through direct protein-protein interactions than catalytic activity in the context of nonalcoholic fatty liver disease (NAFLD), obesity, and type 2 diabetes (T2D). Failure to resolve inflammation resulting in chronic subclinical activation of the immune system may influence the development of metabolic dysregulation. Thus, through both its cleavage and regulation of the bioactivity of peptide hormones and its influence on inflammation, DPP4 exhibits a diverse array of effects that can influence the progression of metabolic disease. Here, we highlight our current understanding of the complex biology of DPP4 at the intersection of inflammation, obesity, T2D, and NAFLD. We compare and review new mechanisms identified in basic laboratory and clinical studies, which may have therapeutic application and relevance to the pathogenesis of obesity and T2D.

Treatment paradigm shifting implications of recent cardiovascular outcome trials: Core insights on the brink of the 2020ies

Based on cardiovascular (CV) outcome trials (CVOTs) being available on the brink of the 2020ies, CV safety assessed by major adverse CV event outcomes has been established for the classes of glucagon-like-peptide-1 receptor agonists (GLP1 RAs), sodium-glucose-co-transporter-2 inhibitors (SGLT2-is), and dipeptidyl-peptidase-4 inhibitors (DPP4is) in patients at very high CV risk. This should be relevant to the whole population with diabetes in general as well as the fact that no new serious and unexpected side effects have emerged within these trials. At the same time, treatment paradigm shifting CV benefit has been confirmed for two classes of diabetes medications (SGLT2is & GLP1 RAs), with important additional benefit of SGLT2is reducing heart failure and hard renal endpoints, both in patients with such diseases, but also in patients being in primary prevention. Moreover, the "soft" renal outcome of albuminurea progression seems to be attenuated by all three classes of drugs discussed in this overview. Still ongoing CVOTs are not expected to essentially change the current notions, with the potential of some differentiation regarding subgroups of primary heart failure populations in relation to treatment with SGLT2is.

Differential indication for SGLT-2 inhibitors versus GLP-1 receptor agonists in patients with established atherosclerotic heart disease or at risk for congestive heart failure

SGLT-2 inhibitors and most GLP-1 receptor agonists demonstrated cardiovascular superiority and reduction of cardiovascular and overall mortality. These results stand as a turning point in the management of diabetes, shifting the focus from controlling glucose levels to mastering the extra-glycemic effects of these new drugs. This narrative review will discuss recent CVOT with focus on SGLT-2 inhibitors and GLP-1 receptor agonists to distinguish relevant patients' characteristics as potential predictors for therapeutic efficacy. It will also examine their efficacy and safety, the differences in their cardiovascular and renal benefits, aiming to convey clinical suggestions for everyday practice.

Effects of glucagon-like peptide-1 receptor agonists on major cardiovascular events in patients with Type 2 diabetes mellitus with or without established cardiovascular disease: a meta-analysis of randomized controlled trials

Aims 

Glucose-lowering, glucagon-like peptide-1 (GLP-1) receptor agonists reduce incidence of major cardiovascular (CV) events in patients with Type 2 diabetes mellitus (DM). However, randomized clinical trials reported inconsistent effects on myocardial infarction (MI) and stroke, and limited data in DM patients without established CV disease (CVD). Very recently, new relevant evidence was available from additional CV outcome trials (CVOTs) that also included large subgroups of patients with DM without established CVD. Thus, the aim of this meta-analysis was to investigate the effects of GLP-1 receptor agonists on major CV events and safety in DM patients with and without established CVD.

Methods and results 

In this trial-level meta-analysis, we analysed data from randomized placebo-controlled CVOTs assessing efficacy and safety of GLP-1 receptor agonists in adult patients with Type 2 DM. We searched PubMed, Embase, Cochrane, ISI Web of Science, SCOPUS, and clinicaltrial.gov databases for eligible trials. Of 360 articles identified and screened for eligibility, seven CVOTs were included, with an overall of 56 004 patients included. The difference in efficacy with respect to the major adverse cardiovascular events (MACE) primary endpoint (including CV mortality, non-fatal MI, and non-fatal stroke) between patients with established CVD and patients with CV risk factors only was not significant [pooled interaction effect, expressed as ratio of hazard ratio (HR) 1.06, 95% confidence interval (CI) 0.85–1.34]. In the analysis of the whole population of DM patients, GLP-1 receptor agonists showed a significant 12% reduction in the hazard of the three-point MACE composite endpoint (HR 0.88, 95% CI 0.80–0.96) and a significant reduction in the risk of CV mortality (HR 0.88, 95% CI 0.79–0.98), all-cause mortality (HR 0.89, 95% CI 0.81–0.97), fatal and non-fatal stroke (HR 0.84, 95% CI 0.76–0.94), and heart failure (HF) hospitalization (HR 0.92, 95% CI 0.86–0.97). No significant effect was observed for fatal and non-fatal MI (HR 0.91, 95% CI 0.82–1.02), although in a sensitivity analysis, based on a less conservative statistical approach, the pooled HR become statistically significant (HR 0.91, 95% CI 0.83–1.00; P = 0.039). No excess of hypoglycaemia, pancreatitis, and pancreatic cancer was observed between GLP-1 receptor agonists and placebo.

Conclusion 

Glucagon-like peptide-1 receptor agonists significantly reduce MACE, CV and total mortality stroke, and hospitalization for HF, with a trend for reduction of MI, in patients with Type 2 DM with and without established CVD.

SGLT-2 inhibitors and GLP-1 receptor agonists for nephroprotection and cardioprotection in patients with diabetes mellitus and chronic kidney disease. A consensus statement by the EURECA-m and the DIABESITY working groups of the ERA-EDTA

Chronic kidney disease (CKD) in patients with diabetes mellitus (DM) is a major problem of public health. Currently, many of these patients experience progression of cardiovascular and renal disease, even when receiving optimal treatment. In previous years, several new drug classes for the treatment of type 2 DM have emerged, including inhibitors of renal sodium-glucose co-transporter-2 (SGLT-2) and glucagon-like peptide-1 (GLP-1) receptor agonists. Apart from reducing glycaemia, these classes were reported to have other beneficial effects for the cardiovascular and renal systems, such as weight loss and blood pressure reduction. Most importantly, in contrast to all previous studies with anti-diabetic agents, a series of recent randomized, placebo-controlled outcome trials showed that SGLT-2 inhibitors and GLP-1 receptor agonists are able to reduce cardiovascular events and all-cause mortality, as well as progression of renal disease, in patients with type 2 DM. This document presents in detail the available evidence on the cardioprotective and nephroprotective effects of SGLT-2 inhibitors and GLP-1 analogues, analyses the potential mechanisms involved in these actions and discusses their place in the treatment of patients with CKD and DM.

Impact of vildagliptin on vascular and fibrotic remodeling of myocardium in experimental diabetic cardiomyopathy

The effect of dipeptidyl peptidase-4 inhibitors (DPP-4is) on myocardium in diabetic cardiomyopathy (DCM) remains a matter of debate. In the current study we investigated the effect of vildagliptin (VILDA, 3 mg/kg/d) on myocardium of DCM focusing on coronary microcirculation as well as on endothelial stress markers (ICAM and VCAM). We divided animals equally into 4 groups; nondiabetic (ND), VILDA per se, DCM and DCM + VILDA and their myocardium was evaluated for the fibro-vascular remodeling immunohistochemically as well as for molecular changes. VILDA had reversed the histological changes occurred in DCM including the disintegration, degeneration, and steatosis of cardiomyocytes with disappearance of the edema fluid. In addition VILDA significantly increased (p < 0.05) density of the coronary microcirculation and relieved endothelial stress. However, it did not prevent the development of fibrotic remodeling including the increased collagen deposition and the significantly upregulated (p < 0.05) corresponding genes. Therefore VILDA may have a positive impact on the microvascular remodeling, but not on fibrotic changes, in DCM.

Clinical significance of quantitative assessment of glucose utilization in patients with ischemic cardiomyopathy

BACKGROUND

The aim of this study was to prospectively quantify the rate of myocardial glucose uptake (MRGlu) in myocardium with different perfusion-metabolism patterns and determine its prognostic value in patients with ischemic cardiomyopathy.

METHODS AND RESULTS

79 patients with ischemic cardiomyopathy were prospectively enrolled for dynamic cardiac FDG PET, and then followed for at least 6 months. Perfusion-metabolism patterns were determined based on visual score analysis of 201Tl SPECT and FDG PET. MRGlu was analyzed using the Patlak kinetic model. The primary end-point was cardiovascular mortality. Significantly higher MRGlu was observed in viable compared with non-viable areas. Negative correlations were found between MRGlu in transmural match and a history of hyperlipidemia, statin usage, and triglyceride levels. Diabetic patients receiving dipeptidyl peptidase-4 inhibitors (DPP4i) had a significantly lower MRGlu in transmural match, mismatch, and reverse mismatch. Patients with MRGlu in transmural match ≥ 23.40 or reverse mismatch ≥ 36.90 had a worse outcome.

CONCLUSIONS

Myocardial glucose utilization was influenced by substrates and medications, including statins and DPP4i. MRGlu could discriminate between viable and non-viable myocardium, and MRGlu in transmural match and reverse mismatch may be prognostic predictors of cardiovascular death in patients with ischemic cardiomyopathy.

Glucagon-Like Peptide-1 Receptor Agonists and Prevention of Stroke Systematic Review of Cardiovascular Outcome Trials With Meta-Analysis

Background and Purpose- The purpose of this study was to conduct a meta-analysis of CVOTs (cardiovascular outcome trials) to evaluate the effect of glucagon-like peptide-1 receptor agonists therapy in reducing the risk of stroke in patients with type 2 diabetes mellitus. Methods- PubMed and other electronic sources were searched until June 20, 2019, to identify relevant studies. Hazard ratios with 95% CIs were used as a measure of the association between use of glucagon-like peptide-1 receptor agonists and risk of stroke after pooling data across trials. Results- Seven CVOTs with 56 004 participants were identified. Use of glucagon-like peptide-1 receptor agonists in patients with type 2 diabetes mellitus was associated with 15% lower risk of nonfatal stroke (P=0.002), 19% lower risk of fatal stroke (P=0.150), and 16% lower risk of total stroke (P=0.001). There was no association between reductions of hemoglobin A1c levels or body weight and risk of stroke. Conclusions- Glucagon-like peptide-1 receptor agonists reduce the risk of nonfatal stroke in patients with T2D.

Sex Differences in Cardiovascular Effectiveness of Newer Glucose-Lowering Drugs Added to Metformin in Type 2 Diabetes Mellitus

Background

Randomized controlled trials showed that newer glucose‐lowering agents are cardioprotective, but most participants were men. It is unknown whether benefits are similar in women.

Methods and Results

Among adults with type 2 diabetes mellitus not controlled with metformin with no prior use of insulin, we assessed for sex differences in the cardiovascular effectiveness and safety of sodium‐glucose‐like transport‐2 inhibitors (SGLT‐2i), glucagon‐like peptide‐1 receptor agonists (GLP‐1RA), dipeptidyl peptidase‐4 inhibitors, initiated as second‐line agents relative to sulfonylureas (reference‐group). We studied type 2 diabetes mellitus American adults with newly dispensed sulfonylureas, SGLT‐2i, GLP‐1RA, or dipeptidyl peptidase‐4 inhibitors (Marketscan‐Database: 2011–2017). We used multivariable Cox proportional hazards models with time‐varying exposure to compare time to first nonfatal cardiovascular event (myocardial infarction/unstable angina, stroke, and heart failure), and safety outcomes between drugs users, and tested for sex–drug interactions. Among 167 254 type 2 diabetes mellitus metformin users (46% women, median age 59 years, at low cardiovascular risk), during a median 4.5‐year follow‐up, cardiovascular events incidence was lower in women than men (14.7 versus 16.7 per 1000‐person‐year). Compared with sulfonylureas, hazard ratios (HRs) for cardiovascular events were lower with GLP‐1RA (adjusted HR‐women: 0.57, 95% CI: 0.48–0.68; aHR‐men: 0.82, 0.71–0.95), dipeptidyl peptidase‐4 inhibitors (aHR‐women: 0.83, 0.77–0.89; aHR‐men: 0.85, 0.79–0.91) and SGLT‐2i (aHR‐women: 0.58, 0.46–0.74; aHR‐men: 0.69, 0.57–0.83). A sex‐by‐drug interaction was statistically significant only for GLP‐1RA (P=0.002), suggesting greater cardiovascular effectiveness in women. Compared with sulfonylureas, risks of adverse events were similarly lower in both sexes for GLP‐1RA (aHR‐women: 0.81, 0.73–0.89; aHR‐men: 0.80, 0.71–0.89), dipeptidyl peptidase‐4 inhibitors (aHR‐women: 0.82, 0.78–0.87; aHR‐men: 0.83, 0.78–0.87) and SGLT‐2i (aHR‐women: 0.68, 0.59–0.78; aHR‐men: 0.67, 0.59–0.78) (all sex–drug interactions for adverse events P>0.05).

Conclusions

Newer glucose‐lowering drugs were associated with lower risk of cardiovascular events than sulfonylureas, with greater effectiveness of GLP‐1RA in women than men. Overall, they appeared safe, with a better safety profile for SGLT‐2i than for GLP‐1RA regardless of sex.

Diabetes drugs and stroke risk: Intensive versus conventional glucose-lowering strategies, and implications of recent cardiovascular outcome trials

People with diabetes mellitus are at higher risk of ischaemic stroke and worse outcomes thereafter. However, whether it is better to prescribe intensive glucose-lowering treatment compared with conventional treatment in people with diabetes to prevent recurrent stroke is debated. It is also crucial to consider whether specific antidiabetic agents are more efficacious and safer than others for prevention of stroke. In this review, we provide an overview of the efficacy of intensive and conventional glucose-lowering treatment in post-stroke management. Our conclusion is that the overall evidence for a beneficial effect of intensive glycaemic control on risk of stroke is limited. We also discuss evidence from recent large clinical trials of thiazolidinediones and new antidiabetic medications, including dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), and sodium-glucose co-transporter-2 inhibitors. On the basis of the findings of these trials, our conclusion is that pioglitazone and the GLP-1RA class (other than short-acting lixisenatide) are likely to lessen the occurrence of cerebrovascular disease (by mechanisms not dependent on glucose-lowering per se), whereas there is no consistent evidence for other drug classes.

CVOTs: What did the endocrinologist learn?

The recent CVOTs which tested the new glucose-lowering drugs (GLD) show that in patients with type 2 diabetes mellitus (T2DM) it is now possible to reduce cardiovascular complications including ischemic events and hospitalization for heart failure, and mortality, and, to some extent, microvascular complications of diabetes, in particular renal outcomes. Additionally CVOTs provide major informations on safety and metabolic effects for long-term use of these drugs. The benefits with GLP-1 RAs are most likely derived through the reduction of atherosclerosis-related events while SGLT-2is seem mostly to reduce heart failure-related events. Specific mechanisms independent from glucose control are involved. Based on CVOTs results it is time, as stated in the new EASD-ADA and ESC/EASD guidelines, to take into consideration such opportunities in the decision-making process when treating T2DM patients, favoring the use of drugs that have shown clear cardiovascular and renal benefits. The treatment decisions require more expertise in the evaluation of cardiovascular and renal risk which becomes a major determinant for the choice of GLD treatment, the target for lipids, the adjustment of anti-hypertensive treatments and the prescription of aspirin. In this context it is essential that endocrinologists-diabetologists communicate more with cardiologists and nephrologists and with the primary care practitioners.

The Effects of DPP-4 Inhibitors, GLP-1RAs, and SGLT-2/1 Inhibitors on Heart Failure Outcomes in Diabetic Patients With and Without Heart Failure History: Insights From CVOTs and Drug Mechanism

Patients with type 2 diabetes (T2D) have a higher risk of heart failure (HF) than healthy people, and the prognosis of patients with diabetes and current or previous HF is worse than that of patients with only diabetes. We reviewed the HF outcomes in recently published cardiovascular outcome trials (CVOTs) of three new classes of anti-diabetic agents, namely, dipeptidyl peptidase-4 inhibitors (DPP-4is), glucagon-like-peptide 1 receptor agonists (GLP-1RAs), and sodium glucose cotransporter-2 inhibitors (SGLT-2is) or SGLT-2 and SGLT-1 dual inhibitors and divided the patients into two groups based on the history of HF (with or without) and analyzed their risks of HHF based on the receipt of the aforementioned anti-diabetes drug types. Since the follow-up period differed among the trials, we expressed the rate of HHF as events/1,000 person-years to describe the HF outcome. At last we pooled the data and analyzed their different effects and mechanisms on heart failure outcomes. Although DPP-4is did not increase the risk of HHF in T2D patients with a history of HF, they were associated with a significantly higher risk of HHF among patients without history of HF. Some GLP-1RAs reduced the risk of macrovascular events, but none of these drugs reduced the risk of HHF in patients with T2D irrespective of their HF history. It was not clarified whether SGLT-1/2is can improve the prognosis of macrovascular events in patients with T2D, but these drugs reduced the risk of HHF regardless of patients' histories of HF. This information may be useful or referential for the "precise" selection of hyperglycemic medications. Further researches still needed to clarify the mechanisms of these anti-diabetic medications.

Series: Implications of the recent CVOTs in type 2 diabetes: Impact on guidelines: The endocrinologist point of view

The management of type 2 diabetes mellitus (T2DM) essentially consists in controlling hyperglycaemia, together with other vascular risk factors, in order to reduce the incidence and severity of diabetic complications. Whereas glucose control using classical glucose-lowering agents (except perhaps metformin) largely fails to reduce cardiovascular disease (CVD), two new pharmacological classes, glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter type 2 inhibitors (SGLT2is), have proven their ability to reduce major cardiovascular events in patients with established CVD. Furthermore, SGLT2is reduced the risk of hospitalisation for heart failure and the progression of renal disease. According to the 2018 ADA-EASD consensus report, the choice of a second agent to be added to metformin should now be driven by the presence or not of atherosclerotic CVD, heart failure or renal disease, all conditions that should promote the use of a SGLT2i or a GLP-1 RA with proven efficacy. Thus endocrinologists have to face a new paradigm in the management of T2DM, with a shift from a primary objective of glucose control without inducing hypoglycaemia and weight gain to a goal of cardiovascular and renal protection, largely independent of glucose control. Of note, however, the latter remains crucial to reduce the risk of microangiopathy.

Dissimilar Effects of Anagliptin and Sitagliptin on Lipoprotein Subclass in Standard or Strong Statin-Treated Patients with Type-2 Diabetes Mellitus: A Subanalysis of the REASON (Randomized Evaluation of Anagliptin versus Sitagliptin on Low-Density LipoproteiN Cholesterol in Diabetes) Trial

The effects of antidiabetic agents on lipoprotein subclasses are assumed to be pivotal, but this assumption has not been studied. We evaluated lipoprotein subclasses in patients, randomly selected from REASON (Randomized Evaluation of Anagliptin versus Sitagliptin On low-density lipoproteiN cholesterol in diabetes) Trial participants, with type-2 diabetes treated with either anagliptin or sitagliptin. We measured total cholesterol (TC) and triglycerides (TG) in 4 (chylomicron (CM), very low-density lipoprotein (VLDL), low density lipoprotein (LDL), and high-density lipoprotein (HDL)) lipoprotein classes and 20 (2 CM, 5 VLDL, 6 LDL, and 7 HDL) lipoprotein subclasses. Between 0 and 52 weeks, TC and TG in lipoprotein and the lipoprotein subclass were distributed differently in patients treated with anagliptin and sitagliptin. The preferable changes in TC and TG levels were observed dominantly in the anagliptin-treated group under standard statin therapy, but the benefits were observed in both the anagliptin- and sitagliptin-treated groups, at least partially under strong statin therapy. In future studies, the atherogenic properties of lipoprotein subclasses might be considered when employing antidiabetic dipeptidyl peptidase-4 (DPP-4) inhibitors, especially in patients with type-2 diabetes who are at risk of atherosclerotic cardiovascular disease (ASCVD) or are undergoing statin treatment.

Conservation of glucagon like peptide-1 level with liraglutide and linagilptin protects the kidney against angiotensin II-induced tissue fibrosis in rats

This study tested the hypothesis that the enhancement of glucagon-like peptide-1 (GLP-1) level through either exogenous supply of GLP-1 agonist, liraglutide or prevention of endogenous GLP-1 degradation with dipeptidyl peptidease-4 inhibitor, lingaliptin ameliorates angiotensin II (Ang II)-induced renal fibrosis. Sprague-Dawley rats were randomly divided into four groups: 0.9% saline or Ang II (500 ng/kg/min) was infused with osmotic minipumps for 4 weeks, defined as sham and Ang II groups. In drug treated groups, liraglutide (0.3 mg/kg) was injected subcutaneously twice daily or linagliptin (8 mg/kg) was administered daily via oral gavage during Ang II infusion. Compared with Ang II stimulation, liraglutide or linagliptin comparatively down-regulated the protein level of the AT₁ receptor, and up-regulated the AT₂ receptor, as identified by a reduced AT₁/AT₂ ratio (all p < 0.05), consistent with less locally-expressed AT₁ receptor and enhanced AT₂ receptor in the glomerular capillaries and proximal tubules of the renal cortex. Furthermore, both drugs significantly increased the expression of GLP-1 receptor and attenuated the protein levels of TLR4, NOX4 and IL-6. The populations of macrophages and α-SMA expressing myofibroblasts decreased with treatment of liraglutide and linagliptin, in coincidence with the reduced expression of phosphor-Smad2/3, Smad4, TGFβ1, and up-regulated Smad7. Along with these modulations, renal morphology was preserved and synthesis of fibronectin/collagen I was down-regulated, as identified by small collagen-rich area in the renal cortex. These results suggest that the preservation of GLP-1 level using liraglutide or linagliptin might be considered as an add-on therapeutic option for inhibiting Ang II induced renal fibrosis and failure.

Thiazolidinediones: the Forgotten Diabetes Medications

PURPOSE OF REVIEW

Thiazolidinediones (TZDs) are the only pharmacologic agents that specifically treat insulin resistance. The beneficial effects of TZDs on the cardiovascular risk factors associated with insulin resistance have been well documented. TZD use has been limited because of concern about safety issues and side effects.

RECENT FINDINGS

Recent studies indicate that cardiovascular toxicity with rosiglitazone and increase in bladder cancer with pioglitazone are no longer significant issues. There are new data which show that pioglitazone treatment reduces myocardial infarctions and ischemic strokes. New data concerning TZD-mediated edema, congestive heart failure, and bone fractures improves the clinician's ability to select patients that will have minimal significant side effects. Thiazolidinediones are now generic and less costly than pharmaceutical company-promoted therapies. Better understanding of the side effects coupled with clear benefits on the components of the insulin resistance syndrome should promote TZD use in treating patients with type 2 diabetes.

Endothelial GLP-1 (Glucagon-Like Peptide-1) Receptor Mediates Cardiovascular Protection by Liraglutide In Mice With Experimental Arterial Hypertension

Supplemental Digital Content is available in the text.

Cardiovascular outcome trials demonstrated that GLP-1 (glucagon-like peptide-1) analogs including liraglutide reduce the risk of cardiovascular events in type 2 diabetes mellitus. Whether GLP-1 analogs reduce the risk for atherosclerosis independent of glycemic control is challenging to elucidate as the GLP-1R (GLP-1 receptor) is expressed on different cell types, including endothelial and immune cells.

Activation of Transient Receptor Potential Channel Vanilloid 4 by DPP-4 (Dipeptidyl Peptidase-4) Inhibitor Vildagliptin Protects Against Diabetic Endothelial Dysfunction

Endothelial dysfunction is an early step to the progression of cardiovascular diseases in diabetes. Apart from their anti-diabetic action, DPP-4 (dipeptidyl peptidase-4) inhibitors also reduce cardiovascular events in diabetic patients. However, the underlying mechanism of the beneficial effect of DPP-4 inhibitor on endothelial function is still obscure. In this study, we intervened type 1 or 2 diabetic model mice with vildagliptin for 4 weeks and measured the vascular reactivity. We found that vildagliptin improved endothelium-dependent vasodilation in diabetic mice independent of GLP-1 (glucagonlike peptide-1), but this effect was blocked by a SIRT1 (Sirtuin 1) inhibitor, Ex527. Mechanistically, vildagliptin-activated Transient Receptor Potential Channel Vanilloid 4 (TRPV4) to promote extracellular calcium uptake in endothelial cells, which activated AMPK (AMP-activated protein kinase)/SIRT1 pathway to counteract hyperglycemia-induced endothelial reactive oxygen species generation and senescence. Vildagliptin directly binds to TRPV4 by forming a hydrogen bond, which is critical to vildagliptin-evoked endothelial calcium intake. Knockout or inhibition of TRPV4 erased the beneficial role of vildagliptin. In addition, activation of SIRT1 by SRT1720 improved endothelial function independent of TRPV4 and reduced TRPV4 transcription to maintain an appropriate calcium level. In summary, our findings prove that vildagliptin protects against hyperglycemia-induced endothelial dysfunction by activating TRPV4-meditaed Ca²⁺ uptake, which helps to re-understand the mechanism of DPP-4 inhibitors and expand the therapeutic scope.

Cardioprotective diabetes drugs: what cardiologists need to know

In patients with diabetes, where cardiovascular morbidity is highly prevalent, recent cardiovascular outcomes trials have identified therapies in the modern glucagon-like peptide 1 receptor agonist (GLP-1RA) and sodium-glucose cotransporter 2 inhibitor (SGLT2i) classes that significantly reduce cardiovascular events. A number of drugs in both classes have demonstrated reductions in the risk of the composite outcome of major adverse cardiovascular events (myocardial infarction, stroke, and cardiovascular death). In addition, SGLT2i drugs have a substantial impact on hospitalization for heart failure. Because GLP-1RA and SGLT2i are effective in reducing cardiovascular events, independent of their effects on blood glucose, cardiologists should be familiar with how to use them. This review outlines the evidence of cardiovascular benefit for current GLP-1RA and SGLT2i drugs, practical information for prescribing them, and putative mechanisms, so that these therapies can be incorporated along with antihypertensives, statins, and antiplatelet therapies into the routine care of patients.

Effects of saxagliptin on adipose tissue inflammation and vascular function in overweight and obese people: a placebo-controlled study

AIMS

To test the effect of the dipeptidyl peptidase-4 inhibitor saxagliptin on adipose tissue inflammation and microvascular function, and whole-body postprandial endothelial function.

METHODS

A randomized, double-blind, placebo-controlled, parallel study was conducted between June 2013 and November 2016 in 44 overweight or obese people without diabetes (saxagliptin, n=28; placebo, n=16). Subcutaneous abdominal adipose tissue biopsies, a 4-h fat-enriched meal test and peripheral arterial tonometry for measurement of endothelial function were performed at baseline and after 6 weeks of treatment with saxagliptin (5 mg/day) or matching placebo.

RESULTS

Forty participants were analysed (saxagliptin, n=26; placebo, n=14). Secretion of interleukin-8 from adipose tissue explants was reduced after saxagliptin (median fold-change from baseline: 0.8 saxagliptin vs 3.3 placebo; P=0.02). Adipose tissue expression of thioredoxin-inhibitory protein (TxNIP) was lower after saxagliptin (0.75 vs 1.0; P=0.02), while there were no significant differences in adipose tissue secretion of interleukin-1b, interleukin-6 or macrophage chemoattractant protein 1 (MCP-1), adipose tissue macrophage content, adipose tissue mRNA levels of mcp1, cd36, cd68, il6, il8, txnip and adpq, and activation of adipose tissue inflammatory pathways [extracellular signal-regulated kinase, c-Jun N-terminal kinase (JNK) and nuclear factor-κB (NF- κB)] or insulin-induced vasodilation of adipose tissue arterioles. Postprandial plasma glucose was slightly lower (by an estimated 0.3 mmol/l; P=0.01), while postprandial insulin, triglyceride levels and endothelial function were unchanged after saxagliptin.

CONCLUSIONS

The effect of saxagliptin on adipose tissue inflammation was relatively modest, with many inflammatory markers unchanged. We also found no evidence that saxagliptin therapy improved adipose tissue arteriole vasodilation or postprandial endothelial function.

Effects of Liraglutide on Cardiovascular Outcomes in Patients With Type 2 Diabetes Mellitus With or Without History of Myocardial Infarction or Stroke

BACKGROUND

The glucagon-like peptide-1 analog liraglutide reduced cardiovascular events and mortality in patients with type 2 diabetes mellitus in the LEADER trial (Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes). In a post hoc analysis, we evaluated the efficacy of liraglutide in those with and without a history of myocardial infarction (MI) and/or stroke.

METHODS

LEADER was a randomized trial of liraglutide (1.8 mg or maximum tolerated dose) versus placebo in 9340 patients with type 2 diabetes mellitus and high cardiovascular risk, with a median follow-up of 3.8 years. The primary outcome was a composite of cardiovascular death, nonfatal MI, or nonfatal stroke (major adverse cardiovascular events). Risk groups in this post hoc analysis were defined by history of MI/stroke, established atherosclerotic cardiovascular disease without MI/stroke, or cardiovascular risk factors alone.

RESULTS

Of the 9340 patients, 3692 (39.5%) had a history of MI/stroke, 3083 (33.0%) had established atherosclerotic cardiovascular disease without MI/stroke, and 2565 (27.5%) had risk factors alone. Major adverse cardiovascular events occurred in 18.8% of patients with a history of MI/stroke (incidence rate, 5.0 per 100 patient-years), 11.6% of patients with established atherosclerotic cardiovascular disease without MI/stroke (incidence rate, 3.0 per 100 patient-years), and 9.8% of patients with cardiovascular risk factors alone (incidence rate, 2.6 per 100 patient-years). Liraglutide reduced major adverse cardiovascular events in patients with a history of MI/stroke (322 of 1865 [17.3%] versus 372 of 1827 patients [20.4%]; hazard ratio, 0.85; 95% CI, 0.73-0.99) and in those with established atherosclerotic cardiovascular disease without MI/stroke (158 of 1538 [10.3%] versus 199 of 1545 patients [12.9%]; hazard ratio, 0.76; 95% CI, 0.62-0.94) compared with placebo. In patients with risk factors alone, the hazard ratio for liraglutide versus placebo was 1.08 (95% CI, 0.84-1.38, P_interaction=0.11). Similar results were seen for secondary outcomes across risk groups.

CONCLUSIONS

In this post hoc analysis of patients with type 2 diabetes mellitus and high cardiovascular risk, liraglutide reduced cardiovascular outcomes both in patients with a history of MI/stroke and in those with established atherosclerotic cardiovascular disease without MI/stroke. The cardiovascular effect appeared neutral in patients with cardiovascular risk factors alone.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01179048.

From NASH to diabetes and from diabetes to NASH: Mechanisms and treatment options

The worldwide prevalence of non-alcoholic fatty liver disease (NAFLD) is estimated to have reached 25% or more in adults. NAFLD is prevalent in obese individuals, but may also affect non-obese insulin-resistant individuals. NAFLD is associated with a 2- to 3-fold increased risk of developing type 2 diabetes (T2D), which may be higher in patients with more severe liver disease - fibrosis increases this risk. In NAFLD, not only the close association with obesity, but also the impairment of many metabolic pathways, including decreased hepatic insulin sensitivity and insulin secretion, increase the risk of developing T2D and related comorbidities. Conversely, patients with diabetes have a higher prevalence of steatohepatitis, liver fibrosis and end-stage liver disease. Genetics and mechanisms involving dysfunctional adipose tissue, lipotoxicity and glucotoxicity appear to play a role. In this review, we discuss the altered pathophysiological mechanisms that underlie the development of T2D in NAFLD and vice versa. Although there is no approved therapy for the treatment of NASH, we discuss pharmacological agents currently available to treat T2D that could potentially be useful for the management of NASH.