GLP-1RAs in type 2 diabetes: mechanisms that underlie cardiovascular effects and overview of cardiovascular outcome data

Incretin-based therapies for the management of cardiometabolic disease in the clinic: Past, present, and future

Among newer classes of drugs for type 2 diabetes mellitus (T2DM), glucagon-like peptide 1 receptor agonists (GLP-1 RAs) are incretin-based agents that lower both blood sugar levels and promote weight loss. They do so by activating pancreatic GLP-1 receptors (GLP-1R) to promote glucose-dependent insulin release and inhibit glucagon secretion. They also act on receptors in the brain and gastrointestinal tract to suppress appetite, slow gastric emptying, and delay glucose absorption. Phase 3 clinical trials have shown that GLP-1 RAs improve cardiovascular outcomes in the setting of T2DM or overweight/obesity in people who have, or are at high risk of having atherosclerotic cardiovascular disease. This is largely driven by reductions in ischemic events, although emerging evidence also supports benefits in other cardiovascular conditions, such as heart failure with preserved ejection fraction. The success of GLP-1 RAs has also seen the evolution of other incretin therapies. Tirzepatide has emerged as a dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 RA, with more striking effects on glycemic control and weight reduction than those achieved by isolated GLP-1R agonism alone. This consists of lowering glycated hemoglobin levels by more than 2% and weight loss exceeding 15% from baseline. Here, we review the pharmacological properties of GLP-1 RAs and tirzepatide and discuss their clinical effectiveness for T2DM and overweight/obesity, including their ability to reduce adverse cardiovascular outcomes. We also delve into the mechanistic basis for these cardioprotective effects and consider the next steps in implementing existing and future incretin-based therapies for the broader management of cardiometabolic disease.

Mechanisms of action and therapeutic applications of GLP-1 and dual GIP/GLP-1 receptor agonists

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are two incretins that bind to their respective receptors and activate the downstream signaling in various tissues and organs. Both GIP and GLP-1 play roles in regulating food intake by stimulating neurons in the brain's satiety center. They also stimulate insulin secretion in pancreatic β-cells, but their effects on glucagon production in pancreatic α-cells differ, with GIP having a glucagonotropic effect during hypoglycemia and GLP-1 exhibiting glucagonostatic effect during hyperglycemia. Additionally, GIP directly stimulates lipogenesis, while GLP-1 indirectly promotes lipolysis, collectively maintaining healthy adipocytes, reducing ectopic fat distribution, and increasing the production and secretion of adiponectin from adipocytes. Together, these two incretins contribute to metabolic homeostasis, preventing both hyperglycemia and hypoglycemia, mitigating dyslipidemia, and reducing the risk of cardiovascular diseases in individuals with type 2 diabetes and obesity. Several GLP-1 and dual GIP/GLP-1 receptor agonists have been developed to harness these pharmacological effects in the treatment of type 2 diabetes, with some demonstrating robust effectiveness in weight management and prevention of cardiovascular diseases. Elucidating the underlying cellular and molecular mechanisms could potentially usher in the development of new generations of incretin mimetics with enhanced efficacy and fewer adverse effects. The treatment guidelines are evolving based on clinical trial outcomes, shaping the management of metabolic and cardiovascular diseases.

Effects of albiglutide on myocardial infarction and ischaemic heart disease outcomes in patients with type 2 diabetes and cardiovascular disease in the Harmony Outcomes trial

AIMS

Large outcome trials have demonstrated cardiovascular benefits of selected glucagon-like peptide-1 (GLP-1) receptor agonists. We examined coronary disease outcomes in the Harmony Outcomes trial of the GLP-1 receptor agonist albiglutide.

METHODS AND RESULTS

Harmony Outcomes was an event-driven, multicenter, double-blind, and placebo-controlled trial involving 9463 patients >40 years of age with type-2 diabetes and established atherosclerotic cardiovascular disease. It tested the effects of albiglutide on the occurrence of a composite primary endpoint, consisting of cardiovascular death, myocardial infarction (MI), or stroke. Within this post-hoc analysis, the effects of albiglutide on MI subtypes and other ischaemic endpoints were analysed.During the median-follow up of 1.6 years, a total of 421 patients (4.5%) experienced at least one MI, with 72 patients having more than one event. Treatment with albiglutide reduced both first events [hazard ratio (HR) 0.75 (0.62-0.91)] and overall events [HR 0.75 (0.61-0.91)] as well as first type 1 [HR 0.73 (0.57-0.92)] and type 2 myocardial infarctions [HR 0.65 (0.46-0.92)]. The effect of albiglutide treatment was consistent for ST-segment elevation [HR 0.69 (0.38-1.26)] and non-ST elevation (HR 0.86 (0.66-1.2) MI.

CONCLUSION

Treatment with the GLP-1 receptor agonist albiglutide resulted in a 25% relative risk reduction in MI that was consistent for type of infarction and presence or absence of ST elevation. Our findings add novel information about the effects of GLP-1 receptor agonists on ischaemic events in patients with type 2 diabetes.

Targeting GLP-1 receptors to reduce nicotine use disorder: Preclinical and clinical evidence

Nicotine use disorder (NUD) remains a leading cause of preventable death in the U.S. Unfortunately, current FDA-approved pharmacotherapies for smoking cessation have limited efficacy and are associated with high rates of relapse. One major barrier to long-term smoking abstinence is body weight gain during withdrawal. Nicotine withdrawal-induced body weight gain can also lead to development of chronic disease states like obesity and type II diabetes mellitus. Therefore, it is critical to identify novel pharmacotherapies for NUD that decrease relapse and nicotine withdrawal symptoms including body weight gain. Recent studies demonstrate that glucagon-like peptide-1 receptor (GLP-1R) agonists attenuate voluntary nicotine taking and seeking and prevent withdrawal-induced hyperphagia and body weight gain. Emerging evidence also suggests that GLP-1R agonists improve cognitive deficits, as well as depressive- and anxiety-like behaviors, which contribute to smoking relapse during withdrawal. While further studies are necessary to fully characterize the effects of GLP-1R agonists on NUD and understand the mechanisms by which GLP-1R agonists decrease nicotine withdrawal-mediated behaviors, the current literature supports GLP-1R-based approaches to treating NUD.

Semaglutide in Cardiometabolic Diseases: SELECTing the Target Population

Cardiovascular diseases remain the main cause of death and disability worldwide. Despite the tremendous improvement in pharmacological, minimally invasive and rehabilitative strategies, global deaths due to cardiovascular diseases are still increasing. Additional risk factors have been recently proposed, and thanks to scientific progress, novel drugs for the control of the main risk factors focusing on the cardiometabolic pathways have been identified. Glucagon-like peptide-1 (GLP-1) receptor agonists represent an innovative step in the management of patients affected by type 2 diabetes mellitus. In addition to their significant efficacy on glycemic homeostasis, some members of this class of drugs have indications in the treatment of obesity. Furthermore, accumulated evidence in the literature has finally suggested a protective role in cardiovascular health. The possible role of GLP-1R agonist drugs (GLP-1RAs) on the mechanisms underlying chronic inflammation and the almost ubiquitous distribution of GLP-1 receptors could explain the enormous versatility of these drugs. Semaglutide is a GLP-1RA recently proven to be effective in cardiovascular outcomes. In the present article, we will review the available data on semaglutide in light of the most recent publications to better characterize the target population achieving cardiovascular benefits.

Real-world study of the concomitant use of biphasic insulin aspart 30/70 with GLP-1 receptor agonist versus first-generation basal insulin with GLP-1 receptor agonist in type 2 diabetes

AIMS

Combining insulin with a glucagon-like peptide-1 receptor agonist (GLP-1RA) to treat type 2 diabetes (T2D) is common. While many studies have investigated concomitant therapy with basal insulin+GLP-1RA, few have reported on premixed insulin+GLP-1RA. We aimed to address this gap using data from the Clinical Practice Research Datalink Aurum database in England.

METHODS

This retrospective cohort study with propensity score matching assessed glycaemic levels and other clinical outcomes in people with T2D, comparing biphasic insulin aspart 30/70 (BIAsp 30) + GLP-1RA with basal insulin (insulin detemir/glargine U100) + GLP-1RA (from 2006 to 2021).

RESULTS

In total, 4770 eligible people were identified; 1511 had a BIAsp 30 + GLP-1RA regimen and were propensity score-matched to an equal number receiving basal+GLP-1RA. There was no significant difference in glycated haemoglobin (HbA1c) reduction between cohorts at 6 months (p = 0.15), with a decrease of -1.07 (95% CI: -1.16; -0.98) %-points (-11.7 mmol/mol [95% CI: -12.7; -10.7]) in the BIAsp 30 + GLP-1RA cohort, versus -0.97 (95% CI: -1.07; -0.88) %-points (-10.6 mmol/mol [95% CI: -11.7; -9.6]) in the basal+GLP-1RA cohort. Body mass index (BMI) decreased by -0.35 kg/m2 (95% CI: -0.52;-0.18) at 6 months with BIAsp 30 + GLP-1RA, versus -0.72 kg/m2 (95% CI: -0.90;-0.54) with basal+GLP-1RA (p = 0.003). BMI was influenced by the initiation sequence of GLP-1RA in relation to insulin (p < 0.0001). Hypoglycaemia rates were low and not significantly different between cohorts.

CONCLUSIONS

Combining BIAsp 30 + GLP-1RA provides glycaemic control with no significant difference to that of propensity score-matched people receiving basal insulin+GLP-1RA, with no increase in hypoglycaemia risk or weight gain.

Sodium-Glucose Cotransporter 2 Inhibitors Reduce the Risk of Hospitalization for Heart Failure and Amputation Rate Compared With Incretin-Based Therapy in Patients With Diabetic Foot Disease: A Nationwide Population-Based Study

OBJECTIVE

Major adverse cardiovascular event (MACE) outcomes associated with sodium-glucose cotransporter 2 inhibitor (SGLT2i) and glucagon-like peptide-1 receptor agonist (GLP-1 RA) therapies remain unclear in patients with type 2 diabetes and newly diagnosed diabetic foot complications (DFCs). This study examined the impact of SGLT2i and GLP-1 RA use on the rates of MACEs and amputations in patients with type 2 diabetes and without cardiovascular disease.

METHODS

Data from the Taiwan National Health Insurance Research Database (2004-2017) were analyzed, focusing on patients with type 2 diabetes without previous MACE and newly diagnosed DFCs. The primary outcome was the first MACE occurrence, and the secondary outcomes included MACE components, all-cause mortality, and lower extremity amputation (LEA) rates.

RESULTS

SGLT2i users showed a significant decrease in the MACE (hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.46-0.88) and hospitalization for heart failure (HR, 0.54; 95% CI, 0.35-0.83) rates compared with dipeptidyl peptidase-4 inhibitor users. The amputation rates were also lower in SGLT2i users without LEA at the first DFC diagnosis (HR, 0.28; 95% CI, 0.10-0.75) and did not increase in those with a history of peripheral artery disease or LEA. No significant differences were observed between dipeptidyl peptidase-4 inhibitor and GLP-1 RA users in terms of the primary or secondary outcomes.

CONCLUSION

In patients with type 2 diabetes initially diagnosed with DFC, SGLT2i are effective in significantly reducing the hospitalization for heart failure and MACE rates. SGLT2i lower the amputation rates, especially in patients who have not previously had a LEA, than the dipeptidyl peptidase-4 inhibitor therapy.

Glucagon-like peptide-1 receptor agonists: new strategies and therapeutic targets to treat atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of cardiovascular mortality and is increasingly prevalent in our population. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) can safely and effectively lower glucose levels while concurrently managing the full spectrum of ASCVD risk factors and improving patients' long-term prognosis. Several cardiovascular outcome trials (CVOTs) have been carried out to further investigate the cardiovascular benefits of GLP-1RAs. Analyzing data from CVOTs can provide insights into the pathophysiologic mechanisms by which GLP-1RAs are linked to ASCVD and define the use of GLP-1RAs in clinical practice. Here, we discussed various mechanisms hypothesized in previous animal and preclinical human studies, including blockade of the production of adhesion molecules and inflammatory factors, induction of endothelial cells' synthesis of nitric oxide, protection of mitochondrial function and restriction of oxidative stress, suppression of NOD-like receptor thermal protein domain associated protein three inflammasome, reduction of foam cell formation and macrophage inflammation, and amelioration of vascular smooth muscle cell dysfunction, to help explain the cardiovascular benefits of GLP-1RAs in CVOTs. This paper provides an overview of the clinical research, molecular processes, and possible therapeutic applications of GLP-1RAs in ASCVD, while also addressing current limitations in the literature and suggesting future research directions.

Beyond the Cold: Activating Brown Adipose Tissue as an Approach to Combat Obesity

With a dramatic increase in the number of obese and overweight people, there is a great need for new anti-obesity therapies. With the discovery of the functionality of brown adipose tissue in adults and the observation of beige fat cells among white fat cells, scientists are looking for substances and methods to increase the activity of these cells. We aimed to describe how scientists have concluded that brown adipose tissue is also present and active in adults, to describe where in the human body these deposits of brown adipose tissue are, to summarize the origin of both brown fat cells and beige fat cells, and, last but not least, to list some of the substances and methods classified as BAT promotion agents with their benefits and side effects. We summarized these findings based on the original literature and reviews in the field, emphasizing the discovery, function, and origins of brown adipose tissue, BAT promotion agents, and batokines. Only studies written in English and with a satisfying rating were identified from electronic searches of PubMed.

Beneficial effects of simultaneously targeting calorie intake and calorie efficiency in diet-induced obese mice

Semaglutide is an anti-diabetes and weight loss drug that decreases food intake, slows gastric emptying, and increases insulin secretion. Patients begin treatment with low-dose semaglutide and increase dosage over time as efficacy plateaus. With increasing dosage, there is also greater incidence of gastrointestinal side effects. One reason for the plateau in semaglutide efficacy despite continued low food intake is due to compensatory actions whereby the body becomes more metabolically efficient to defend against further weight loss. Mitochondrial uncoupler drugs decrease metabolic efficiency, therefore we sought to investigate the combination therapy of semaglutide with the mitochondrial uncoupler BAM15 in diet-induced obese mice. Mice were fed high-fat western diet (WD) and stratified into six treatment groups including WD control, BAM15, low-dose semaglutide without or with BAM15, and high-dose semaglutide without or with BAM15. Combining BAM15 with either semaglutide dose decreased body fat and liver triglycerides, which was not achieved by any monotherapy, while high-dose semaglutide with BAM15 had the greatest effect on glucose homeostasis. This study demonstrates a novel approach to improve weight loss without loss of lean mass and improve glucose control by simultaneously targeting energy intake and energy efficiency. Such a combination may decrease the need for semaglutide dose escalation and hence minimize potential gastrointestinal side effects.

Association Between the Magnitude of Glycemic Control and Body Weight Loss With GLP-1 Receptor Agonists and Risk of Atherosclerotic Cardiovascular Disease: A Systematic Review and Meta-analyses of Randomized Diabetes Cardiovascular Outcomes Trials

PURPOSE

Reduction of major atherosclerotic cardiovascular events (MACE) has not been consistent among different glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in patients with type 2 diabetes mellitus (T2DM). The aim of this study was to assess the association between the magnitude of glycemic control, body weight loss, and reductions in systolic blood pressure (SBP) and low-density lipoprotein cholesterol (LDL-C) achieved through GLP-1 RA therapy and MACE.

METHODS

Electronic databases (MEDLINE, CENTRAL, SCOPUS) were searched through March 2023. Studies were eligible if they were cardiovascular outcome trials (CVOTs) comparing GLP-1 RAs versus placebo in T2DM patients. The outcome of interest was 3-point MACE - cardiovascular death, myocardial infarction, or stroke. Random-effects meta-regression analyses evaluated the associations between reductions of HbA1c, body weight, SBP and LDL-C and reduction of MACE.

RESULTS

Overall, 8 CVOTs were included (60079 patients, 30693 with GLP-1 RAs). Reductions of HbA1C were associated with the reduction of 3P-MACE (Log RR -0.290 [95% CI -0.515;-0.064], p = 0.012), with an estimated RR reduction of 25% for each 1% absolute reduction in HbA1C levels. Body weight loss was associated with the reduction of 3P-MACE (Log RR -0.068 [95% CI -0.135;-0.001], p = 0.047), with an estimated RR reduction of 7% for each 1 kg reduction in body weight. Reductions of SBP (Log RR -0.058 [95% CI -0.192;0.076], p = 0.396) and LDL-C (Log RR -0.602 [95% CI -4.157;2.953], p = 0.740) were not associated with the reduction of 3P-MACE.

CONCLUSIONS

In T2DM patients, more potent GLP-1 RAs in reducing HbA1c and body weight were associated with greater reductions of MACE.

Mechanisms and treatment of obesity-related hypertension-Part 1: Mechanisms

The prevalence of obesity has tripled over the past five decades. Obesity, especially visceral obesity, is closely related to hypertension, increasing the risk of primary (essential) hypertension by 65%-75%. Hypertension is a major risk factor for cardiovascular disease, the leading cause of death worldwide, and its prevalence is rapidly increasing following the pandemic rise in obesity. Although the causal relationship between obesity and high blood pressure (BP) is well established, the detailed mechanisms for such association are still under research. For more than 30 years sympathetic nervous system (SNS) and kidney sodium reabsorption activation, secondary to insulin resistance and compensatory hyperinsulinemia, have been considered as primary mediators of elevated BP in obesity. However, experimental and clinical data show that severe insulin resistance and hyperinsulinemia can occur in the absence of elevated BP, challenging the causal relationship between insulin resistance and hyperinsulinemia as the key factor linking obesity to hypertension. The purpose of Part 1 of this review is to summarize the available data on recently emerging mechanisms believed to contribute to obesity-related hypertension through increased sodium reabsorption and volume expansion, such as: physical compression of the kidney by perirenal/intrarenal fat and overactivation of the systemic/renal SNS and the renin-angiotensin-aldosterone system. The role of hyperleptinemia, impaired chemoreceptor and baroreceptor reflexes, and increased perivascular fat is also discussed. Specifically targeting these mechanisms may pave the way for a new therapeutic intervention in the treatment of obesity-related hypertension in the context of 'precision medicine' principles, which will be discussed in Part 2.

Biology and Clinical Use of Glucagon-Like Peptide-1 Receptor Agonists in Vascular Protection

Glucagon-like peptide-1 receptor agonists (GLP1RA) are incretin agents initially designed for the treatment of type 2 diabetes mellitus but because of pleiotropic actions are now used to reduce cardiovascular disease in people with type 2 diabetes mellitus and in some instances as approved treatments for obesity. In this review we highlight the biology and pharmacology of GLP1RA. We review the evidence for clinical benefit on major adverse cardiovascular outcomes in addition to modulation of cardiometabolic risk factors including reductions in weight, blood pressure, improvement in lipid profiles, and effects on kidney function. Guidance is provided on indications and potential adverse effects to consider. Finally, we describe the evolving landscape of GLP1RA and including novel glucagon-like peptide-1-based dual/polyagonist therapies that are being evaluated for weight loss, type 2 diabetes mellitus, and cardiorenal benefit.

Beyond the Cardiovascular Effects of Glucagon-like Peptide-1 Receptor Agonists: Body Slimming and Plaque Stabilization. Are New Statins Born?

Atherosclerosis is a chronic inflammatory disease characterized by lipid and inflammatory cell deposits in the inner layer of large- and medium-sized elastic and muscular arteries. Diabetes mellitus (DM) significantly increases the risk of cardiovascular diseases and the overall and cardiovascular mortality, and it is a pro-atherogenic factor that induces atherosclerosis development and/or accelerates its progression through a multifactorial process. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a new class of drugs, belonging to the armamentarium to fight type 2 DM, that have shown robust reductions in atherosclerotic events and all-cause mortality in all studies. Preclinical studies have shown that GLP-1RAs play a role in the immunomodulation of atherosclerosis, affecting multiple pathways involved in plaque development and progression. In this review, we wanted to explore the translational power of such preclinical studies by analyzing the most recent clinical trials investigating the atheroprotective effect of GLP-1RAs.

Endothelial Function in Patients with Multiple Sclerosis: The Role of GLP-1 Agonists, Lipoprotein Subfractions, and Redox Balance

INTRODUCTION

Epidemiological studies have suggested an increased vascular risk in patients with multiple sclerosis (MS). There is increasing evidence of the beneficial effects of GLP-1 agonists (GLP-1a) in preventing vascular complications and slowing the progression of neurodegeneration. Our objective was to explore the changes in the endothelial function of MS patients after 12 months of GLP-1a therapy. We also explored the role of lipoprotein subfractions and the antioxidant capacity of plasma.

METHODS

MS patients were enrolled in a prospective, unicentric study. GLP-1a (dulaglutide) was administered to 13 patients. The control population consisted of 12 subjects. Endothelial function was determined by peripheral arterial tonometry and expressed as reperfusion hyperemia index (RHI). Trolox equivalent antioxidant capacity (TEAC) was used to assess the total antioxidant capacity of the plasma. The levels of lipoprotein subfractions were evaluated.

RESULTS

The GLP-1a group did not have a significant change in their RHIs after 12 months (2.1 ± 0.6 vs. 2.1 ± 0.7; p = 0.807). However, a significant increase in their TEACs was observed (4.1 ± 1.4 vs. 5.2 ± 0.5 mmol/L, p = 0.010). On the contrary, the subjects in the control group had a significant worsening of their RHIs (2.1 ± 0.5 vs. 1.8 ± 0.6; p = 0.030), without significant changes in their TEACs. Except for a significant decrease in very-low-density lipoprotein (VLDL) (30.8 ± 10.2 vs. 22.6 ± 8.3 mg/dL, p = 0.043), no other significant changes in the variables were observed in the control group. VLDL levels (beta = -0.637, p = 0.001), the use of GLP-1a therapy (beta = 0.560, p = 0.003), and small LDL (beta = 0.339, p = 0.043) were the only significant variables in the model that predicted the follow-up RHI.

CONCLUSION

Our results suggest that the application of additional GLP-1a therapy may have atheroprotective and antioxidant effects in MS patients with high MS activity and thus may prospectively mitigate their vascular risk. However, the lipoprotein profile may also play an important role in the atherogenic risk of MS subjects.

Newer glucose-lowering drugs and risk of dementia: A systematic review and meta-analysis of observational studies

BACKGROUND

Preclinical studies have suggested potential beneficial effects of newer glucose-lowering drugs (GLDs) including dipeptidyl peptidase (DPP)-4 inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), and sodium glucose co-transporter-2 (SGLT2) inhibitors, in protecting humans against cognitive decline and dementia. However, population studies aiming to demonstrate such cognitive benefits from newer GLDs have produced mixed findings. This meta-analysis aimed to evaluate the association between newer GLDs and risk of dementia in adults with type 2 diabetes (T2D).

METHODS

Electronic databases were searched up to March 11, 2022 to include observational studies that examined the association between DPP-4 inhibitors, GLP-1RAs, and SGLT2 inhibitors and risk of dementia (including all-cause dementia, Alzheimer's disease [AD], and vascular dementia [VD]) in people with T2D. We conducted a random-effects meta-analysis to calculate the relative risk (RR) with 95% confidence interval (CI) for each class of newer GLD.

RESULTS

Ten studies (from nine articles) involving 819,511 individuals with T2D were included. Three studies found that SGLT2 inhibitor users had a lower risk of all-cause dementia than non-SGLT2 inhibitor users (RR, 0.62; 95% CI, 0.39-0.97). Five studies found that users versus nonusers of GLP-1RAs were associated with a significant reduction in the risk of all-cause dementia (RR, 0.72; 95% CI, 0.54-0.97). However, a meta-analysis for AD and VD was unavailable for SGLT2 inhibitors and GLP-1RAs because only one study was included for each drug. In seven studies, users vs. nonusers of DPP-4 inhibitors were significantly associated with a decreased risk of all-cause dementia (RR, 0.84; 95% CI, 0.74-0.94) and VD (RR, 0.59; 95% CI, 0.47-0.75) but not AD (RR, 0.82; 95% CI, 0.63-1.08).

CONCLUSION

Newer GLDs were associated with a decreased risk of all-cause dementia in people with T2D. Because of the observational nature and significant heterogeneity between studies, the results should be interpreted with caution. Further research is warranted to confirm our findings.

Multifaceted Roles of GLP-1 and Its Analogs: A Review on Molecular Mechanisms with a Cardiotherapeutic Perspective

Diabetes is one of the chronic metabolic disorders which poses a multitude of life-debilitating challenges, including cardiac muscle impairment, which eventually results in heart failure. The incretin hormone glucagon-like peptide-1 (GLP-1) has gained distinct recognition in reinstating glucose homeostasis in diabetes, while it is now largely accepted that it has an array of biological effects in the body. Several lines of evidence have revealed that GLP-1 and its analogs possess cardioprotective effects by various mechanisms related to cardiac contractility, myocardial glucose uptake, cardiac oxidative stress and ischemia/reperfusion injury, and mitochondrial homeostasis. Upon binding to GLP-1 receptor (GLP-1R), GLP-1 and its analogs exert their effects via adenylyl cyclase-mediated cAMP elevation and subsequent activation of cAMP-dependent protein kinase(s) which stimulates the insulin release in conjunction with enhanced Ca²⁺ and ATP levels. Recent findings have suggested additional downstream molecular pathways stirred by long-term exposure of GLP-1 analogs, which pave the way for the development of potential therapeutic molecules with longer lasting beneficial effects against diabetic cardiomyopathies. This review provides a comprehensive overview of the recent advances in the understanding of the GLP-1R-dependent and -independent actions of GLP-1 and its analogs in the protection against cardiomyopathies.

Primary Occurrence of Cardiovascular Events After Adding Sodium-Glucose Cotransporter-2 Inhibitors or Glucagon-like Peptide-1 Receptor Agonists Compared With Dipeptidyl Peptidase-4 Inhibitors: A Cohort Study in Veterans With Diabetes

BACKGROUND

The effectiveness of glucagon-like peptide-1 receptor agonists (GLP1RA) and sodium-glucose cotransporter-2 inhibitors (SGLT2i) in preventing major adverse cardiac events (MACE) is uncertain for those without preexisting cardiovascular disease.

OBJECTIVE

To test the hypothesis that MACE incidence was lower with the addition of GLP1RA or SGLT2i compared with dipeptidyl peptidase-4 inhibitors (DPP4i) for primary cardiovascular prevention.

DESIGN

Retrospective cohort study of U.S. veterans from 2001 to 2019.

SETTING

Veterans aged 18 years or older receiving care from the Veterans Health Administration, with data linkage to Medicare, Medicaid, and the National Death Index.

PATIENTS

Veterans adding GLP1RA, SGLT2i, or DPP4i onto metformin, sulfonylurea, or insulin treatment alone or in combination. Episodes were stratified by history of cardiovascular disease.

MEASUREMENTS

Study outcomes were MACE (acute myocardial infarction, stroke, or cardiovascular death) and heart failure (HF) hospitalization. Cox models compared the outcome between medication groups using pairwise comparisons in a weighted cohort adjusted for covariates.

RESULTS

The cohort included 28 759 GLP1RA versus 28 628 DPP4i weighted pairs and 21 200 SGLT2i versus 21 170 DPP4i weighted pairs. Median age was 67 years, and diabetes duration was 8.5 years. Glucagon-like peptide-1 receptor agonists were associated with lower MACE and HF versus DPP4i (adjusted hazard ratio [aHR], 0.82 [95% CI, 0.72 to 0.94]), yielding an adjusted risk difference (aRD) of 3.2 events (CI, 1.1 to 5.0) per 1000 person-years. Sodium-glucose cotransporter-2 inhibitors were not associated with MACE and HF (aHR, 0.91 [CI, 0.78 to 1.08]; aRD, 1.28 [-1.12 to 3.32]) compared with DPP4i.

LIMITATION

Residual confounding; use of DPP4i, GLP1RA, and SGLT2i as first-line therapies were not examined.

CONCLUSION

The addition of GLP1RA was associated with primary reductions of MACE and HF hospitalization compared with DPP4i use; SGLT2i addition was not associated with primary MACE prevention.

PRIMARY FUNDING SOURCE

VA Clinical Science Research and Development and supported in part by the Centers for Diabetes Translation Research.

Exploring the Complex Relationship between Diabetes and Cardiovascular Complications: Understanding Diabetic Cardiomyopathy and Promising Therapies

Diabetes mellitus (DM) and cardiovascular complications are two unmet medical emergencies that can occur together. The rising incidence of heart failure in diabetic populations, in addition to apparent coronary heart disease, ischemia, and hypertension-related complications, has created a more challenging situation. Diabetes, as a predominant cardio-renal metabolic syndrome, is related to severe vascular risk factors, and it underlies various complex pathophysiological pathways at the metabolic and molecular level that progress and converge toward the development of diabetic cardiomyopathy (DCM). DCM involves several downstream cascades that cause structural and functional alterations of the diabetic heart, such as diastolic dysfunction progressing into systolic dysfunction, cardiomyocyte hypertrophy, myocardial fibrosis, and subsequent heart failure over time. The effects of glucagon-like peptide-1 (GLP-1) analogues and sodium-glucose cotransporter-2 (SGLT-2) inhibitors on cardiovascular (CV) outcomes in diabetes have shown promising results, including improved contractile bioenergetics and significant cardiovascular benefits. The purpose of this article is to highlight the various pathophysiological, metabolic, and molecular pathways that contribute to the development of DCM and its significant effects on cardiac morphology and functioning. Additionally, this article will discuss the potential therapies that may be available in the future.

The protective effects of SGLT-2 inhibitors, GLP-1 receptor agonists, and RAAS blockers against renal injury in patients with type 2 diabetes

Diabetic kidney disease is one of the most severe complications of type 2 diabetes mellitus. Patients with diabetic kidney disease have a worse prognosis in terms of mortality and morbidity, compared with patients who have diabetes alone. Strict control of blood pressure and blood glucose is the primary method for prevention of initial kidney damage and delaying further progression of existing damage. Other management approaches include the use of exogenous drugs that can effectively protect the kidneys from diabetes, such as sodium-glucose transporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and renin-angiotensin-aldosterone system blockers. These drugs may protect against kidney injury through various molecular mechanisms. This review focuses on renal impairment in patients with type 2 diabetes; it discusses the direct and indirect effects of sodium-glucose transporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and renin-angiotensin-aldosterone system blockers on diabetic kidney disease. Finally, it discusses the effects of combination treatment with two or three types of drugs in patients with chronic kidney disease.

Cost-utility analysis of semaglutide for type 2 diabetes after its addition to the National Medical Insurance System in China

INTRODUCTION

The main research purpose is to compare the long-term cost-effectiveness of semaglutide (SEMA) with that of dulaglutide (DULA) for patients with inadequately controlled type 2 diabetes throughout their lifetime. If necessary, the second aim is to investigate a further price cut for SEMA to provide sound advice for government drug price adjustments.

METHODS

Cost-utility analysis was performed by the United Kingdom Prospective Diabetes Study Outcomes Model 2 (UKPDS OM2) from the perspective of health care providers in China. Baseline characteristics and clinical efficacy of SEMA and DULA were sourced from the high-dose comparison in the SUSTAIN-7 trial. A binary search was used to identify the scope for further reduction in the price of SEMA. The impact of individual parameters was assessed with sensitivity analyses.

RESULTS

Main analysis (SEMA vs. DULA) revealed a mean difference in quality-adjusted life years (QALYs) of 0.04 QALYs and costs of $1132.29. The incremental cost-utility ratio was $26 957.44/QALY, showing that SEMA was a better option compared with DULA. In sensitivity analyses, the discount rate made the greatest contribution to the incremental cost-utility ratio. In the binary search, there was still scope to reduce the SEMA cost further by approximately 6.83% to be cost-effective, taking DULA as a reference.

CONCLUSION

After its addition to the National Medical Insurance System in China, SEMA is expected to be a cost-effective choice compared with DULA for patients with type 2 diabetes with inadequately controlled from the cost-utility analysis. However, there is still scope to reduce the annual cost of SEMA further.

Clinical Insight on Semaglutide for Chronic Weight Management in Adults: Patient Selection and Special Considerations

Losses of 5-10% or more of initial body weight are associated with improvements in obesity-related comorbidities. However, attaining and sustaining this level of weight loss is challenging. The novel anti-obesity medication semaglutide 2.4 mg injected subcutaneously once weekly as an adjunct to a reduced-calorie diet and physical activity helps patients achieve average losses of 9.6-17.4% of initial body weight at week 68, as well as improvements in cardiometabolic and psychosocial indices. Despite these average benefits, prescribers should carefully assess the suitability of patients for this medication. In this paper, we discuss considerations for the selection of individuals who are candidates for semaglutide and special considerations related to the use of this medication. These include its efficacy and safety, as well as its contraindications, potential adverse effects, management of comorbidities and drug interactions, insurance coverage and cost, and patient preferences.

Are arrhythmias the drivers of sudden cardiac death in heart failure with preserved ejection fraction? A review

In patients with heart failure with preserved ejection fraction (HFpEF), sudden cardiac death (SCD) accounts for approximately 25-30% of all-cause mortality and 40% of cardiovascular mortality in properly adjudicated large clinical trials. The mechanism of SCD in HFpEF remains unknown but thought to be driven by arrhythmic events. Apart from atrial fibrillation, which is prevalent in approximately 45% of HFpEF patients, the true burden of other cardiac arrhythmias in HFpEF remains undetermined. The incidence and risk of clinically significant advanced cardiac conduction disease with bradyarrhythmias and ventricular arrhythmias remain less known. Recommendations have been made for long-term cardiac rhythm monitoring to determine the incidence of arrhythmias and clarify mechanisms and mode of death in HFpEF patients. In animal studies, spontaneous ventricular arrhythmias and SCD are significantly elevated in HFpEF animals compared with controls without heart failure. In humans, these studies are scant, with a few published small-size studies suggesting an increased incidence of ventricular arrhythmias in HFpEF. Higher rates of clinically significant conduction disease and cardiac pacing are seen in HFpEF compared with the general population. Excepting atrial fibrillation, the predictive effect of other arrhythmias on heart failure hospitalization, all-cause mortality, and precisely SCD remains unknown. Given the high occurrence of SCD in the HFpEF population, it could potentially become a target for therapeutic interventions if driven by arrhythmias. Studies to address these knowledge gaps are urgently warranted. In this review, we have summarized data on arrhythmias and SCD in HFpEF while highlighting avenues for future research in this area.

Pharmacogenomics of GLP-1 receptor agonists: Focus on pharmacological profile

Type 2 Diabetes mellitus (T2DM) is a multifactorial metabolic disorder also known as a silent killer disease. Macrovascular and microvascular complications associated with diabetes worsen the condition leading to higher comorbidity and mortality rate. Currently, available treatment strategies for diabetes include biguanides, sulfonylureas, alpha-glucosidase inhibitors, thiazolidinediones, insulin and its analogs, DPP-4 (dipeptidyl-peptidase-4) inhibitors, SGLT-2 inhibitors, and Glucagon Like Peptide-1 receptor agonists (GLP-1RAs). Synthetic agonists of GLP-1 hormone, GLP-1RAs are an emerging class of anti-diabetic drugs which target the pathophysiology of diabetes through various mechanisms and at multiple sites. They promote insulin secretion from beta cells, and the proliferation of beta cells inhibits glucagon secretion, delays gastric emptying and induces satiety. However, treatment is reported to be associated with inter-individual variations and adverse drug reactions, which are also influenced by genetic variations. There have been a few pharmacogenetic studies have been carried out on this drug class. This review discusses all the available GLP-1RAs, their pharmacokinetics, pharmacodynamics and genetic variation affecting the inter-individual variation.

Protection against stroke with glucagon-like peptide-1 receptor agonists: a comprehensive review of potential mechanisms

Several randomized controlled trials have demonstrated the benefits of glucagon-like peptide-1 receptor agonists (GLP-1RAs) on ischemic stroke in patients with diabetes. In this review, we summarize and discuss the potential mechanisms of stroke protection by GLP-1RAs. GLP-1RAs exert multiple anti-atherosclerotic effects contributing to stroke prevention such as enhanced plaque stability, reduced vascular smooth muscle proliferation, increased nitric oxide, and improved endothelial function. GLP-1RAs also lower the risk of stroke by reducing traditional stroke risk factors including hyperglycemia, hypertension, and dyslipidemia. Independently of these peripheral actions, GLP-1RAs show direct cerebral effects in animal stroke models, such as reduction of infarct volume, apoptosis, oxidative stress, neuroinflammation, excitotoxicity, blood-brain barrier permeability, and increased neurogenesis, neuroplasticity, angiogenesis, and brain perfusion. Despite these encouraging findings, further research is still needed to understand more thoroughly the mechanisms by which GLP-1RAs may mediate stroke protection specifically in the human diabetic brain.

Recent Progress in the Diagnosis and Management of Type 2 Diabetes Mellitus in the Era of COVID-19 and Single Cell Multi-Omics Technologies

Type 2 diabetes mellitus (T2DM) is one of the world’s leading causes of death and life-threatening conditions. Therefore, we review the complex vicious circle of causes responsible for T2DM and risk factors such as the western diet, obesity, genetic predisposition, environmental factors, and SARS-CoV-2 infection. The prevalence and economic burden of T2DM on societal and healthcare systems are dissected. Recent progress on the diagnosis and clinical management of T2DM, including both non-pharmacological and latest pharmacological treatment regimens, are summarized. The treatment of T2DM is becoming more complex as new medications are approved. This review is focused on the non-insulin treatments of T2DM to reach optimal therapy beyond glycemic management. We review experimental and clinical findings of SARS-CoV-2 risks that are attributable to T2DM patients. Finally, we shed light on the recent single-cell-based technologies and multi-omics approaches that have reached breakthroughs in the understanding of the pathomechanism of T2DM.

Cardiovascular outcomes trials: a paradigm shift in the current management of type 2 diabetes

Cardiovascular disease (CVD) is the leading cause of mortality and morbidity in patients with type 2 diabetes (T2D). Historical concerns about cardiovascular (CV) risks associated with certain glucose-lowering medications gave rise to the introduction of cardiovascular outcomes trials (CVOTs). Initially implemented to help monitor the CV safety of glucose-lowering drugs in patients with T2D, who either had established CVD or were at high risk of CVD, data that emerged from some of these trials started to show benefits. Alongside the anticipated CV safety of many of these agents, evidence for certain sodium-glucose transporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have revealed potential cardioprotective effects in patients with T2D who are at high risk of CVD events. Reductions in 3-point major adverse CV events (3P-MACE) and CV death have been noted in some of these CVOTs, with additional benefits including reduced risks of hospitalisation for heart failure, progression of renal disease, and all-cause mortality. These new data are leading to a paradigm shift in the current management of T2D, with international guidelines now prioritising SGLT2 inhibitors and/or GLP-1 RAs in certain patient populations. However, clinicians are faced with a large volume of CVOT data when seeking to use this evidence base to bring opportunities to improve CV, heart failure and renal outcomes, and even reduce mortality, in their patients with T2D. The aim of this review is to provide an in-depth summary of CVOT data-crystallising the key findings, from safety to efficacy-and to offer a practical perspective for physicians. Finally, we discuss the next steps for the post-CVOT era, with ongoing studies that may further transform clinical practice and improve outcomes for people with T2D, heart failure or renal disease.

Management of Type 2 Diabetes Mellitus in Elderly Patients with Frailty and/or Sarcopenia

The life expectancy of the population is increasing worldwide due to improvements in the prevention, diagnosis, and treatment of diseases. This favors a higher prevalence of type 2 diabetes mellitus (T2DM) in the elderly. Sarcopenia and frailty are also frequently present in aging. These three entities share common mechanisms such as insulin resistance, chronic inflammation, and mitochondrial dysfunction. The coexistence of these situations worsens the prognosis of elderly patients. In this paper, we review the main measures for the prevention and management of sarcopenia and/or frailty in elderly patients with T2DM.

New Hypoglycemic Drugs: Combination Drugs and Targets Discovery

New hypoglycemic drugs, including glucagon-like peptide 1 receptor agonists (GLP-1RA), dipeptidyl peptidase-4 inhibitors (DPP-4i) and sodium-glucose cotransporter 2 inhibitors (SGLT-2i), which brings more options for the treatment of type 2 diabetes (T2DM). They are generally well tolerated, although caution is required in rare cases. Clinical trials have show good glycemic control with combination therapy with new hypoglycemic drugs in prediabetes and T2DM (mostly traditional stepwise therapy), but early combination therapy appears to have faster, more, and longer-lasting benefits. With the widespread clinical application of oral semaglutide, it is time to develop combinations drugs containing new hypoglycemic drugs, especially SGLT-2i and/or GLP-1RA, to control the risk of prediabetes and newly diagnosed T2DM and its cardiovascular complications, while improving patient compliance. Clinical and preclinical studies support that SGLT-2i exerts its protective effect on heart failure through indirect and direct effects. How this comprehensive protective effect regulates the dynamic changes of heart genes needs further study. We provide ideas for the development of heart failure drugs from the perspective of "clinical drug-mechanism-intensive disease treatment." This will help to accelerate the development of heart failure drugs, and to some extent guide the use of heart failure drugs.

Pharmacokinetic and pharmacodynamic studies of supaglutide in rats and monkeys

We demonstrated recently that supaglutide, a novel GLP-1 mimetic generated by recombinant fusion protein techniques, exerted hypoglycemic effects in type 2 diabetes db/db mice and spontaneous diabetic monkeys. In this study, we investigated the pharmacokinetics and pharmacodynamics of supaglutide by single subcutaneous and intravenous injection(s) in rats and rhesus monkeys, as well as fourconsecutive subcutaneous injections in monkeys.We found the half-life (t1/2) of supaglutide was 39.7 hours and 35.8 hours at dosing 0.1 mg/kg upon subcutaneous or intravenous administration respectively, in rhesus monkeys. The plasma supaglutide peaked at 8-10 hours, while the plasma drug exposure levels increased with the increase of dose, showing approximately a linear pharmacokinetic characteristic. The elimination kinetics (Ke) were found to be similar between subcutaneous (∼0.025 in rats and ∼0.018 in monkeys) and intravenous administration (0.021 in rats and 0.020 in monkeys), whereas the bioavailability was found to be 31.1% in rats and 63.9% in monkeys. In monkeys, a single dose injection of supaglutide markedly decreased the random blood glucose levels that reaching the maxima effects in 14-16 hours, gradually recovered and returned to the baseline level approximately after 72 hours. 125I-supaglutide was found mainly distributed in the serum and organs rich in blood supply. Urine was found to be the primary excretion route of supaglutide, following by feces, but mostly not in bile.Our results show that supaglutide possess linear pharmacokinetic characteristics associated with prolonged hypoglycemic effects inanimals,suggestinga potential weekly dosing therapeutic reagent for the treatment of type 2 diabetes and metabolic diseases.

Glucose-Lowering and the Risk of Cardiovascular Events With Antidiabetic Therapies: A Systematic Review and Additive-Effects Network Meta-Analysis

Aim

To assess the impact of the HbA1c levels achieved with antidiabetic therapies (ADTs) on the risk of MACE.

Methods

A systematic search was performed in PubMed, Cochrane, and ClinicalTrials. gov for RCTs published up to March 2022 reporting the occurrence of MACE and all-cause mortality in individuals with T2DM treated with all marketed ADTs, including a sample size ≥100 individuals in each study arm and follow-up ≥24 weeks. A systematic review and additive-effects network meta-analysis with random effects and a multivariate meta-regression were utilized to assess the impact of achieved HbA1c on incident MACE.

Results

We included 126 RCTs with 143 treatment arms, 270,874 individuals, and 740,295 individuals-years who were randomized to an active treatment vs. control group. Among all ADTs, only therapy with SGLT2i, GLP1-RA, or pioglitazone similarly reduced the risk of MACE compared to placebo. The achievement of HbA1c ≤ 7.0% in RCTs with the 3 drug classes in the active arm was associated with an adjusted HR of 0.91 (95% CI 0.80, 0.97; p = 0.017) compared with HbA1c&gt;7.0%, without affecting all-cause mortality. These results, however, were not maintained among all ADTs.

Conclusions

Achieving lower glucose levels with SGLT2i, GLP1-RA, or pioglitazone is linearly associated with a reduced risk of MACEs, without affecting all-cause mortality.

Systematic Review Registration

www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020213127, identifier: CRD42020213127.

Prediction of the Effects of Liraglutide on Kidney and Cardiovascular Outcomes Based on Short-Term Changes in Multiple Risk Markers

Aims: The LEADER trial demonstrated that the glucagon-like peptide-1 receptor agonist (GLP1-RA) liraglutide reduces kidney and cardiovascular (CV) risk in patients with type 2 diabetes. We previously developed a Parameter Response Efficacy (PRE) score that translates multiple short-term risk marker changes, from baseline to first available follow-up measurement, into a predicted long-term drug effect on clinical outcomes. The objective of this study was to assess the accuracy of the PRE score in predicting the efficacy of liraglutide in reducing the risk of kidney and CV outcomes.

Methods: Short-term changes in glycated hemoglobin (HbA1c), systolic blood pressure (BP), urinary-albumin-creatinine-ratio (UACR), hemoglobin, body weight, high-density-lipoprotein (HDL) cholesterol, low-density-lipoprotein (LDL) cholesterol, and potassium were monitored in the LEADER trial. Associations between risk markers and kidney or CV outcomes were established using a multivariable Cox proportional hazards model in a separate pooled database of 6,355 patients with type 2 diabetes. The regression coefficients were then applied to the short-term risk markers in the LEADER trial to predict the effects of liraglutide on kidney (defined as a composite of doubling of serum creatinine or end-stage kidney disease) and CV (defined as a composite of non-fatal myocardial infarction, non-fatal stroke, and CV death) outcomes.

Results: Liraglutide compared to placebo reduced HbA1c (1.4%), systolic BP (3.0 mmHg), UACR (13.2%), body weight (2.3 kg), hemoglobin (2.6 g/L), and increased HDL-cholesterol (0.01 mmol/L) (all p-values <0.01). Integrating multiple risk marker changes in the PRE score resulted in a predicted relative risk reduction (RRR) of 16.2% (95% CI 13.7–18.6) on kidney outcomes which was close to the observed RRR of 15.5% (95% CI -9.0–34.6). For the CV outcome, the PRE score predicted a 7.6% (95% CI 6.8–8.3) RRR, which was less than the observed 13.2% (95% CI 3.2–22.2) RRR.

Conclusion: Integrating multiple short-term risk markers using the PRE score adequately predicted the effect of liraglutide on the composite kidney outcome. However, the PRE score underestimated the effect of liraglutide for the composite CV outcome, suggesting that the risk markers included in the PRE score do not fully capture the CV benefit of liraglutide.

Liraglutide preserves CD34+ stem cells from dysfunction Induced by high glucose exposure

Background

Glucagon like peptide-1 receptor agonists (GLP-1RAs) have shown to reduce mortality and cardiovascular events in patients with type 2 diabetes mellitus (T2DM). Since the impairment in number and function of vasculotrophic circulating CD34⁺ hematopoietic stem progenitor cells (HSPCs) in T2D has been reported to increase cardiovascular (CV) risk, we hypothesized that one of the mechanisms whereby GLP-1 RAs exert CV protective effects may be related to the ability to improve CD34⁺ HSPC function.

Methods

In cord blood (CB)-derived CD34⁺ HSPC, the expression of GLP-1 receptor (GLP-1R) mRNA, receptor protein and intracellular signaling was evaluated by RT-qPCR and Western Blot respectively. CD34⁺ HSPCs were exposed to high glucose (HG) condition and GLP-1RA liraglutide (LIRA) was added before as well as after functional impairment. Proliferation, CXCR4/SDF-1α axis activity and intracellular ROS production of CD34⁺ HSPC were evaluated.

Results

CD34⁺ HSPCs express GLP-1R at transcriptional and protein level. LIRA treatment prevented and rescued HSPC proliferation, CXCR4/SDF-1α axis activity and metabolic imbalance from HG-induced impairment. LIRA stimulation promoted intracellular cAMP accumulation as well as ERK1/2 and AKT signaling activation. The selective GLP-1R antagonist exendin (9–39) abrogated LIRA-dependent ERK1/2 and AKT phosphorylation along with the related protective effects.

Conclusion

We provided the first evidence that CD34⁺ HSPC express GLP-1R and that LIRA can favorably impact on cell dysfunction due to HG exposure. These findings open new perspectives on the favorable CV effects of GLP-1 RAs in T2DM patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01486-9.

Vascular hyperacetylation is associated with vascular smooth muscle dysfunction in a rat model of non-obese type 2 diabetes

Background

Advanced type 2 diabetes mellitus (T2DM) accelerates vascular smooth muscle cell (VSMC) dysfunction which contributes to the development of vasculopathy, associated with the highest degree of morbidity of T2DM. Lysine acetylation, a post-translational modification (PTM), has been associated with metabolic diseases and its complications. Whether levels of global lysine acetylation are altered in vasculature from advanced T2DM remains undetermined. We hypothesized that VSMC undergoes dysregulation in advanced T2DM which is associated with vascular hyperacetylation.

Methods

Aged male Goto Kakizaki (GK) rats, a non-obese murine model of T2DM, and age-matched male Wistar rats (control group) were used in this study. Thoracic aortas were isolated and examined for measurement of global levels of lysine acetylation, and vascular reactivity studies were conducted using a wire myograph. Direct arterial blood pressure was assessed by carotid catheterization. Cultured human VSMCs were used to investigate whether lysine acetylation participates in high glucose-induced reactive oxygen species (ROS), a crucial factor triggering diabetic vascular dysfunction.

Results

The GK rats exhibited marked glucose intolerance as well as insulin resistance. Cardiovascular complications in GK rats were confirmed by elevated arterial blood pressure and reduced VSMC-dependent vasorelaxation. These complications were correlated with high levels of vascular global lysine acetylation. Human VSMC cultures incubated under high glucose conditions displayed elevated ROS levels and increased global lysine acetylation. Inhibition of hyperacetylation by garcinol, a lysine acetyltransferase and p300/CBP association factor (PCAF) inhibitor, reduced high glucose-induced ROS production in VSMC.

Conclusion

This study provides evidence that vascular hyperacetylation is associated with VSMC dysfunction in advanced T2DM. Understanding lysine acetylation regulation in blood vessels from diabetics may provide insight into the mechanisms of diabetic vascular dysfunction, and opportunities for novel therapeutic approaches to treat diabetic vascular complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00441-4.

GLP-1 receptor agonists and cardiovascular outcomes in patients with type 2 diabetes: Clinical evidence and best practice

ABSTRACT

Cardiovascular disease (CVD) is a major cause of death and disability among people with type 2 diabetes (T2D), presenting a significant impact on longevity, patient quality of life, and health care costs. In the United States, attainment of recommended glycemic targets is low and T2D-related cardiovascular complications remain a significant burden. Many glucose-lowering treatment options are available, but glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 (SGLT-2) inhibitors are recommended in recent guidelines as the preferred add-on therapy to metformin to improve glycemic control. This is particularly the case for patients with T2D and established atherosclerotic CVD, at high risk of atherosclerotic CVD, and/or with chronic kidney disease. Recommendations were based on GLP-1RA and SGLT-2 inhibitor cardiovascular outcomes trials (CVOTs), which consistently showed that these agents pose no additional cardiovascular risk compared with placebo. Three GLP-1RAs (liraglutide, dulaglutide, and subcutaneous semaglutide) demonstrated significantly lower major adverse cardiovascular events versus placebo and are now approved for this indication. However, to realize improvement in outcomes in the clinical setting, organized, systematic, and coordinated approaches to patient management are also needed. For example, nurse-led diabetes self-management education and support programs have been shown to be effective. This article explores T2D management with emphasis on cardiovascular risk and CVOTs performed to date and reviews the clinical experience with GLP-1RAs for managing hyperglycemia and their impact on cardiovascular risk. In addition, practical guidance is given for key health care providers involved in the care of patients with T2D with cardiovascular risk outside of diabetes clinics/endocrinology centers.

GLP1R Attenuates Sympathetic Response to High Glucose via Carotid Body Inhibition

Supplemental Digital Content is available in the text.

Aberrant sympathetic nerve activity exacerbates cardiovascular risk in hypertension and diabetes, which are common comorbidities, yet clinically sympathetic nerve activity remains poorly controlled. The hypertensive diabetic state is associated with increased reflex sensitivity and tonic drive from the peripheral chemoreceptors, the cause of which is unknown. We have previously shown hypertension to be critically dependent on the carotid body (CB) input in spontaneously hypertensive rat, a model that also exhibits a number of diabetic traits. CB overstimulation by insulin and leptin has been similarly implicated in the development of increased sympathetic nerve activity in metabolic syndrome and obesity. Thus, we hypothesized that in hypertensive diabetic state (spontaneously hypertensive rat), the CB is sensitized by altered metabolic signaling causing excessive sympathetic activity levels and dysfunctional reflex regulation.

Cardiovascular Outcomes with Finerenone According to Glycemic Status at Baseline and Prior Treatment with Newer Antidiabetics among Patients with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) and cardiovascular disease are closely interconnected. We sought to determine the cardioprotective action of finerenone according to prior treatment with newer antidiabetics and glycemic status. We searched PubMed and Cochrane Library from inception to October 1, 2021 for randomized controlled trials (RCTs) assessing the effect of finerenone on major adverse cardiovascular outcomes in patients with T2DM. We set the primary endpoint as major adverse cardiovascular events (MACE), defined as the composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. We finally included two RCTs in our quantitative synthesis. Compared to placebo, finerenone induced a 23% risk reduction for the composite cardiovascular endpoint, regardless of prior glycemia. We also showed that finerenone provided significant cardiovascular benefit for obese patients with T2DM compared to placebo, although this benefit was diminished for subjects with a body mass index lower than 30 kg/m2. Finally, the combination of finerenone with sodium-glucose co-transporter-2 inhibitors or glucagon-like peptide-1 receptor agonists did not produce a significant risk reduction for MACE. We conclude that finerenone provides significant cardiovascular benefits for patients with T2DM, especially for those who are obese, while glycemic status or treatment with newer antidiabetics at baseline does not affect the observed cardioprotective action.

Effects of Antidiabetic Drugs on Endothelial Function in Patients With Type 2 Diabetes Mellitus: A Bayesian Network Meta-Analysis

BACKGROUND

The changes of endothelial function in type 2 diabetes mellitus (T2DM) patients are closely associated with the development of cardiovascular disease (CVD). However, it is still unclear whether commonly used antidiabetic drugs can improve endothelial function. Flow-mediated dilation (FMD) is a noninvasive tool for evaluating endothelial function, which typically examines changes in the brachial artery diameter in response to ischemia using ultrasound. We performed a network meta-analysis (NMA) to explore the associations between changes in endothelial function and antidiabetic drugs by evaluating FMD in T2DM patients.

METHODS

We systematically searched several electronic databases for randomized controlled trials (RCTs) published from inception until January 25, 2022 with no language restriction. The primary outcome was FMD change in all studies, and we performed subgroup analysis in T2DM patients without CVD. NMA was performed to calculate the mean differences (MDs) with 95% confidence intervals (CIs).

RESULTS

From the 1,987 candidate articles identified in the initial search, 30 RCTs were eventually included in the analysis. In all studies, glucagon-like peptide-1 receptor (GLP-1R) agonists [MD = 3.70 (1.39-5.97)], TZD [MD = 1.96 (0.006-3.89)] produced improvement of FMD change compared to lifestyle intervention. GLP-1R agonists [MD = 3.33 (1.36-5.34) and MD = 3.30 (1.21-5.43)] showed significantly greater improvements in FMD change in pairwise comparisons with sulfonylureas and placebo. SGLT-2i also showed efficacy compared to sulfonylureas (MD = 1.89, 95% CI, 0.10, 3.75). In studies of T2DM patients without CVD, GLP-1R agonists [MD = 3.53 (1.24-5.76)], and TZD [MD = 2.30 (0.27-3.24)] produced improvements in FMD change compared to lifestyle treatment. GLP-1R agonists [MD = 3.25 (1.13-5.40), and MD = 3.85 (1.68-6.13)] showed significantly greater improvements in pairwise comparisons with sulfonylureas, and placebo.

CONCLUSION

In T2DM patients, both GLP-1R agonists, SGLT-2i and TZD have favorable effects to improve endothelial function in T2DM patients. In T2DM patients without CVD, GLP-1R agonists had a greater effect to improve endothelial function than sulfonylureas. These suggested that GLP-1R agonists are associated with significantly improved endothelial function in T2DM patients.

Optimal Type 2 Diabetes Mellitus Management and Active Ageing

Type two diabetes mellitus (T2DM) represents a chronic condition with increasing prevalence worldwide among the older population. The T2DM condition increases the risk of micro and macrovascular complications as well as the risk of geriatric syndromes such as falls, fractures and cognitive impairment. The management of T2DM in the older population represents a challenge for the clinician, and a Comprehensive Geriatric Assessment should always be prioritized, in order to tailor the glycated hemoglobin target according to functional and cognitive status comorbidities, life expectancy and type of therapy. According to the most recent guidelines, older adults with T2DM should be categorized into three groups: healthy patients with good functional status, patients with complications and reduced functionality and patients at the end of life; for each group the target for glycemic control is different, also according to the type of treatment drug. The therapeutic approach should always begin with lifestyle changes; after that, several lines of therapy are available, with different mechanisms of action and potential effects other than glucose level reduction. Particular interest is growing in sodium-glucose cotransporter-2 inhibitors, due to their effect on the cardiovascular system. In this review, we evaluate the therapeutic options available for the treatment of older diabetic patients, to ensure a correct treatment approach.

Primary care management of type 2 diabetes: a comparison of the efficacy and safety of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 inhibitors (DPP4is) exert their effects via the incretin system, which augments glucose-dependent insulin secretion in response to nutrient intake (the 'incretin effect'). Both classes are well-established pharmacologic options for the management of glycemic control in individuals with type 2 diabetes (T2D) after failure of first-line metformin; however, they have inherent differences in their mechanisms of action that are reflected in their clinical safety and efficacy profiles. GLP-1RAs have high glycemic efficacy and are associated with weight loss and, in some cases, cardioprotective effects, with a side-effect profile of predominantly transient gastrointestinal adverse events. Most GLP-1RAs are administered as subcutaneous injection, although an oral formulation of one GLP-1RA, semaglutide, has recently become available. DPP4is provide moderate glycemic control, are weight-neutral, and do not offer any cardiovascular benefits, but are generally well tolerated. DPP4is are all administered orally. This narrative review aims to provide guidance for a primary care audience on the similarities and differences between GLP-1RA and DPP4i therapies, with a focus on their mechanism of action, clinical safety, efficacy, and real-world effectiveness. The role of incretin-based therapies in the T2D treatment paradigm, including key considerations for guiding treatment decisions, will also be discussed.

Vascular and metabolic effects of SGLT2i and GLP-1 in heart failure patients

Alterations of endothelial function, inflammatory activation, and nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway are involved in the pathophysiology of heart failure. Metabolic alterations have been studied in the myocardium of heart failure (HF) patients; alterations in ketone body and amino acid/protein metabolism have been described in patients affected by HF, as well as mitochondrial dysfunction and other modified metabolic signaling. However, their possible contributions toward cardiac function impairment in HF patients are not completely known. Recently, sodium-glucose co-transporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) have emerged as a new class of drugs designed to treat patients with type 2 diabetes (T2D), but have also been shown to be protective against HF-related events and CV mortality. To date, the protective cardiovascular effects of these drugs in patients with and without T2D are not completely understood and several mechanisms have been proposed. In this review, we discuss on vascular and metabolic effects of SGLT2i and GLP-1 in HF patients.

Similar cardiovascular outcomes in patients with diabetes and established or high risk for coronary vascular disease treated with dulaglutide with and without baseline metformin

OBJECTIVE

Recent European Guidelines for Diabetes, Prediabetes and Cardiovascular Diseases introduced a shift in managing patients with type 2 diabetes at high risk for or established cardiovascular (CV) disease by recommending GLP-1 receptor agonists and SGLT-2 inhibitors as initial glucose-lowering therapy. This is questioned since outcome trials of these drug classes had metformin as background therapy. In this post hoc analysis, the effect of dulaglutide on CV events was investigated according to the baseline metformin therapy by means of a subgroup analysis of the Researching Cardiovascular Events with a Weekly Incretin in Diabetes (REWIND) trial.

RESEARCH DESIGN AND METHODS

Patients in REWIND (n = 9901; women: 46.3%; mean age: 66.2 years) had type 2 diabetes and either a previous CV event (31%) or high CV risk (69%). They were randomized (1:1) to sc. dulaglutide (1.5 mg/weekly) or placebo in addition to standard of care. The primary outcome was the first of a composite of nonfatal myocardial infarction, nonfatal stroke, and death from cardiovascular or unknown causes. Key secondary outcomes included a microvascular composite endpoint, all-cause death, and heart failure. The effect of dulaglutide in patients with and without baseline metformin was evaluated by a Cox regression hazard model with baseline metformin, dulaglutide assignment, and their interaction as independent variables. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by a Cox regression model with adjustments for factors differing at baseline between people with vs. without metformin, identified using the backward selection.

RESULTS

Compared to patients with metformin at baseline (n = 8037; 81%), those without metformin (n = 1864; 19%) were older and slightly less obese and had higher proportions of women, prior CV events, heart failure, and renal disease. The primary outcome occurred in 976 (12%) participants with baseline metformin and in 281 (15%) without. There was no significant difference in the effect of dulaglutide on the primary outcome in patients with vs. without metformin at baseline [HR 0.92 (CI 0.81-1.05) vs. 0.78 (CI 0.61-0.99); interaction P = 0.18]. Findings for key secondary outcomes were similar in patients with and without baseline metformin.

CONCLUSION

This analysis suggests that the cardioprotective effect of dulaglutide is unaffected by the baseline use of metformin therapy.

Incorporating SGLT2i and GLP-1RA for Cardiovascular and Kidney Disease Risk Reduction: Call for Action to the Cardiology Community

Multiple sodium glucose cotransporter-2 inhibitors (SGLT-2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) have been shown to impart significant cardiovascular and kidney benefits, but are underused in clinical practice. Both SGLT-2i and GLP-1RA were first studied as glucose-lowering drugs, which may have impeded uptake by cardiologists in the wake of proven cardiovascular efficacy. Their significant effect on cardiovascular and kidney outcomes, which are largely independent of glucose-lowering effects, must drive a broader use of these drugs. Cardiologists are 3 times more likely than endocrinologists to see patients with both type 2 diabetes and cardiovascular disease, thus they are ideally positioned to share responsibility for SGLT-2i and GLP-1RA treatment with primary care providers. In order to increase adoption, SGLT-2i and GLP-1RA must be reframed as primarily cardiovascular and kidney disease risk-reducing agents with a side effect of glucose-lowering. Coordinated and multifaceted interventions engaging clinicians, patients, payers, professional societies, and health systems must be implemented to incentivize the adoption of these medications as part of routine cardiovascular and kidney care. Greater use of SGLT-2i and GLP-1RA will improve outcomes for patients with type 2 diabetes at high risk for cardiovascular and kidney disease.

Diabetes and kidney disease: emphasis on treatment with SGLT-2 inhibitors and GLP-1 receptor agonists

Kidney disease is a frequent microvascular complication of both type 1 and type 2 diabetes. Historic trials have demonstrated that a tight glycaemic control is the most powerful approach to decrease the chances of developing diabetic nephropathy. However, having an HbA1c < 7% does not completely suppress the risk of kidney disease. The observed residual risk is likely ascribable to two phenomena: 1- the presence of risk factors and alterations additive to and independent of glycaemia, and 2- the activation of long-lasting imbalances by periods of exposure to uncontrolled glycemia, a phenomenon referred to as metabolic memory or legacy effect. Long-lasting oxidative stress, epigenetic alterations, cellular senescence, and the resulting chronic low-grade inflammation are all candidate mechanisms explaining the development of nephropathy despite proper control of risk factors. Recently, two classes of drugs, i.e. glucagon-like peptide (GLP) 1 receptor agonists (RA) and sodium-glucose transporter 2 inhibitors (SGLT-i) have changed this scenario. Indeed, cardiovascular outcome and other trials have clearly shown a renoprotective effect for these drugs, well-beyond their glucose-lowering properties. In this review, we summarize: 1- selected key trials and mechanisms underlying the development of diabetic kidney disease and 2- the results relative to renal endpoints in clinical trials of GLP-1 RA and SGLT-2i. Then, we briefly discuss some of the hypotheses posited to explain the marked renoprotective properties of these two classes, evidencing the still existing gaps in knowledge and proposing future directions to further implement the use of these powerful, disease-modifying drugs.

Small dense low-density lipoprotein-lowering agents

Metabolic disorders, including obesity, diabetes, and hyperlipidemia, as well as cardiovascular diseases (CVD), particularly atherosclerosis, are still leading causes of death worldwide. Plasma levels of low-density lipoprotein (LDL) are currently being considered as a critical risk factor for the diseases mentioned above, especially atherosclerosis. Because of the heterogeneous nature of LDL, many studies have already been conducted on its subclasses, especially small dense LDL (sdLDL). According to available evidence, sdLDL levels can be considered as an ideal alternative to LDL levels for monitoring CVD and early diagnosis of atherosclerosis. Recently, several researchers have focused on factors that are able to decrease sdLDL levels and improve health quality. Therefore, the purpose of this study is to describe the production process of sdLDL particles and review the effects of pharmaceutical and dietary agents as well as lifestyle on sdLDL plasma levels. In brief, their mechanisms of action are discussed. Apparently, cholesterol and LDL-lowering compounds are also effective in the reduction of sdLDL levels. In addition, improving lipid profile, especially the reduction of triglyceride levels, appropriate regimen, and lifestyle can decrease sdLDL levels. Therefore, all the aforementioned parameters should be taken into consideration simultaneously in sdLDL levels reducing strategies.

Obesity-induced changes in human islet G protein-coupled receptor expression: Implications for metabolic regulation

G protein-coupled receptors (GPCRs) are a large family of cell surface receptors that are the targets for many different classes of pharmacotherapy. The islets of Langerhans are central to appropriate glucose homeostasis through their secretion of insulin, and islet function can be modified by ligands acting at the large number of GPCRs that islets express. The human islet GPCRome is not a static entity, but one that is altered under pathophysiological conditions and, in this review, we have compared expression of GPCR mRNAs in human islets obtained from normal weight range donors, and those with a weight range classified as obese. We have also considered the likely outcomes on islet function that the altered GPCR expression status confers and the possible impact that adipokines, secreted from expanded fat depots, could have at those GPCRs showing altered expression in obesity.

A Review on the Efficacy and Safety of Oral Semaglutide

There are numerous treatment options currently available for patients with type 2 diabetes mellitus; however, a multitude of patients continue to have inadequately controlled glycemic levels with their current antihyperglycemic regimen. Furthermore, the American Diabetes Association guidelines increasingly highlight the importance of multifactorial management and optimizing medication regimens that include cardiovascular, renal, and/or weight benefits in patients with type 2 diabetes mellitus. Glucagon-like peptide-1 receptor agonists belong to a novel class of type 2 diabetes mellitus agents that are becoming increasingly prevalent owing to their ability to improve glycemic status without the risk of hypoglycemia. Currently, there are three US Food and Drug Administration-approved glucagon-like peptide-1 receptor agonists, subcutaneous semaglutide, dulaglutide, and liraglutide, that also have an indication for reducing major adverse cardiovascular events in patients with type 2 diabetes mellitus and established cardiovascular disease. However, these agents are not often the first options because of their subcutaneous administration. Nevertheless, co-formulation of oral semaglutide with an absorption enhancer has shown to increase its bioavailability and has made its oral absorption possible. In the PIONEER trials, oral semaglutide effectively lowered blood glucose levels, and showed benefits on weight and cardiovascular outcomes; however, there is no Food and Drug Administration indication approved yet as the SOUL trial is still ongoing. Such characteristics of oral semaglutide may improve and increase its use compared to subcutaneous agents and possibly lead to earlier cardiovascular protection in addition to achieving glycemic control.

Cardiovascular Outcomes in Trials of New Antidiabetic Drug Classes

Type 2 diabetes is among the most prevalent chronic diseases worldwide and the prevention of associated cardiovascular complications is an important treatment goal. Sodium–glucose co-transporter 2 (SGLT2) inhibitors, glucagon-like peptide 1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors are second-line options after metformin, while cardiovascular outcome trials have been conducted to establish the cardiovascular safety of these antidiabetic drug classes. SGLT2 inhibitors have been shown to have the best overall mortality, renal and cardiovascular outcomes. Reduction in hospitalisation for heart failure is particularly consistent. GLP-1 receptor agonists have also showed some benefits, especially in stroke prevention. DPP-4 inhibitors showed neutral effects on cardiovascular outcomes, but may increase the incidence of heart failure. Favourable outcomes observed in trials of SGLT2 inhibitors mean that these should be the preferred second-line option. DPP-4 inhibitors are useful for patients with diabetes at low cardiovascular risk.