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1.
Risk factor reduction in type 2 diabetes demands a multifactorial approach.
Rydén, L, Ferrannini, G, Mellbin, L
European journal of preventive cardiology. 2019;(2_suppl):81-91
Abstract
Dysglycaemia (i.e. type 2 diabetes mellitus or impaired glucose tolerance) is not only common in patients with cardiovascular disease but increases the risk for future cardiovascular complications. Hyperglycaemia, the hallmark of diabetes, has since long been considered to be the link between diabetes and cardiovascular disease. Diabetes is, however, a complex, multifactorial disorder to which, for example, insulin resistance, endothelial dysfunction and factors such as increased thrombogenicity, hypertension and dyslipidaemia contribute. Thus, treatment needs to be multifactorial and to take cardiovascular aspects into account. Life-style adjustments are, together with blood pressure, lipid and glucose control, important parts of such management. Recent trial data reveal a beneficial effect on cardiovascular prognosis and mortality of blood glucose lowering agents belonging to the classes: sodium-glucose-transporter 2 inhibitors and glucagon-like peptide 1 agonists. The precise mechanisms by which certain sodium-glucose-transporter 2 inhibitors and glucagon-like peptide receptor agonists lead to these beneficial effects are only partly understood. An important impact of the benefits of sodium-glucose-transporter 2 inhibitors is a reduction in heart failure while glucagon-like peptide receptor agonists may retard the development of atherosclerotic vascular disease or stabilising plaques. Although there has been a considerable improvement in the prognosis for people with atherosclerotic diseases over the last decades there is still a gap between those with dysglycaemia, who are at higher risk, than those without dysglycaemia. This residual risk is reasonably related to two major factors: a demand for improved management and a need for new and improved therapeutic opportunities of type 2 diabetes, both routes to an improved prognosis that are at hands. This review is a comprehensive description of the possibilities to improve the prognosis for patients with dysglycaemia by a multifactorial management according to the most recent European guidelines issued in 2019 by the European Society of Cardiology in collaboration with the European Association for the Study of Diabetes.
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2.
The incretin system in healthy humans: The role of GIP and GLP-1.
Holst, JJ
Metabolism: clinical and experimental. 2019;:46-55
Abstract
The incretin effect, the amplification of insulin secretion occurring when glucose is taken in orally as compared to infused intravenously, is one of the factors that help the body to tolerate carbohydrate/glucose ingestion. These include 1) amount and type of carbohydrates; 2) gastric emptying rate; 3) digestion and absorption of the carbohydrates; 4) secretion and effect of the incretin hormones; 5) disposition of absorbed nutrients/glucose. The incretin effect can also be viewed as the fraction of the ingested glucose load handled via gastrointestinal mechanisms (including the incretin effect); it is calculated by comparison of the amount of glucose required to copy, by intravenous infusion, the oral load. Typically, for 75 g of oral glucose, about 25 g are required. This means that the GastroIntestinal Glucose Disposal (GIGD) is 66%. Both the GIGD and the incretin effect depend on the amount of glucose ingested: for higher doses the GIGD may amount to 80%, which shows that this effect is a major contributor to glucose tolerance. The main mechanism behind it is stimulation of insulin secretion by a proportional secretion of the insulinotropic hormones GIP and GLP-1. Recently it has become possible to estimate their contributions in healthy humans using specific and potent receptor antagonists. Both hormones act to improve glucose tolerance (i.e. the antagonists impair tolerance) and their effects are additive. GIP seems to be quantitatively the most important, particularly regarding insulin secretion, whereas the action of GLP-1 is mainly displayed via inhibition of glucagon secretion.
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3.
The effect of sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 agonists on cardiovascular disease in patients with type 2 diabetes.
Dey, AK, Groenendyk, J, Mehta, NN, Gourgari, E
Clinical cardiology. 2019;(3):406-412
Abstract
Patients with type 2 diabetes have a significantly increased risk of cardiovascular disease (CVD) compared to the general population-with CVD accounting for two out of every three deaths in patients with diabetes. In 2008, the FDA suggested that CVD risk should be evaluated for any new antidiabetic therapy, leading to a multitude of large CVD outcome trials to assess CVD risk from these medications. Interestingly, several of these outcome trials with new novel antidiabetic therapies have demonstrated a clear and definite CVD advantage at mid-term follow up in high-risk patients with T2DM. In this review, we discuss two relatively new classes of diabetic drugs, sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 agonists, and their efficacy in improving cardiovascular outcomes.
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4.
Glucagon-Like Peptide-1 Receptor Agonists and Cardiovascular Risk Reduction in Type 2 Diabetes Mellitus: Is It a Class Effect?
Li, Y, Rosenblit, PD
Current cardiology reports. 2018;(11):113
Abstract
PURPOSE OF REVIEW Mimetics and analogs that extend the half-life of native glucagon-like peptide-1 (GLP-1), i.e., glucagon-like peptide-1 receptor agonists (GLP-1 RAs), at therapeutic doses, are indicated as adjuncts to diet and exercise, to improve glycemic control in adults with type 2 diabetes mellitus (T2DM). In patients with T2DM, GLP-1 RAs not only affect improvements in impaired beta cell and alpha cell function, suppress appetite, and induce weight loss but also possess multiple cardiovascular protective properties that potentially have a beneficial impact on atherosclerotic cardiovascular disease (ASCVD) morbidity and mortality. RECENT FINDINGS Required to demonstrate CV safety, compared to standard-of-care antidiabetic therapies, GLP-1 RAs have revealed statistically significant non-inferiority (p < 0.001), among CV outcome trials (CVOTs) thus far completed. Once-daily liraglutide and once-weekly semaglutide demonstrated significant superiority (p = 0.01 and p = 0.02, respectively), reducing 3-point composite major adverse cardiovascular events (MACE) in extreme risk secondary prevention adults with T2DM. Once-weekly exenatide demonstrated only a non-significant (p = 0.06) favorable trend for CV superiority, possibly due to in-trial mishaps, including placebo drop-ins with other CV protective medications. The short half-life lixisenatide was neutral (p = 0.81) in reducing MACE, most likely due to ineffective once-daily dosing. Structural differences among GLP-1 mimetics and analogs may explain potency differences in both A1C reduction and weight loss that may parallel important cardiovascular protective properties of the GLP-1 RA class. Significant superiority in reducing 3-point composite MACE in adults with T2DM with GLP-1 RAs has been limited to liraglutide and semaglutide. Careful attention to within-trial drop-in of cardioprotective antidiabetic agents assuring equipoise between placebo and investigational product groups might demonstrate significant MACE risk reduction with once-weekly exenatide. Maintenance of 24-h circulating levels, by an alternative administration method, may resurrect lixisenatide as a cardioprotective agent. Before a GLP-1 RA bioequivalence "class effect" claim for composite MACE risk reduction superiority can be fully discussed, we are obliged to wait for the pending results of CVOTs with other GLP-1 RAs, particularly albiglutide and dulaglutide, where steric hindrance may potentially inhibit full mimicry of pharmacologic GLP-1.
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5.
Glucagon like peptide-1 (GLP-1) likes Alzheimer's disease.
Yildirim Simsir, I, Soyaltin, UE, Cetinkalp, S
Diabetes & metabolic syndrome. 2018;(3):469-475
Abstract
Glucagon-like peptide-1 (GLP-1) is a 30 amino acid long peptide hormone derived from the proglucagon gene and secreted in the distal small intestine when food enters the duodenum. GLP-1 is also produced in the central nervous system (CNS), predominantly in the brainstem, and subsequently transported to a large number of regions in the CNS. Neuronal cells in nucleus tractus solitarius (NTS) can synthesize GLP-1 and extends to hypothalamus, some thalamic and cortical areas. A G protein coupled receptor (GPCR) provides the majority of GLP-1 actions. GLP-1 receptor activation triggers some in vivo signaling pathways. GLP-1 receptor agonists (GLP-1 RA) are used in the treatment diabetes and obesity. GLP-1 stimulates insulin secretion, inhibits glucagon secretion, decreases food intake, reduces appetite, delays gastric emptying, provides weight reduction, and protects β cells from apoptosis. Alzheimer's disease (AD) is the most prevalent form of dementia. It is characterized by cognitive insufficiencies and behavioral changes that impact memory and learning abilities, daily functioning and quality of life. Hyperinsulinemia and insulin resistance, which are known as pathophysiological features of the T2DM, have also been demonstrated to have significant impact on cognitive impairment. It is thought that GLP-1 affects neurological and cognitive functions, as well as its regulatory effect on glucose metabolism. The pathophysiological relationship between GLP-1 and AD is discussed in this review.
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6.
Incretins and Lipid Metabolism.
Tsimihodimos, V, Elisaf, M
Current medicinal chemistry. 2018;(18):2133-2139
Abstract
BACKGROUND Recent findings indicate that incretin hormones and incretin-based therapies may affect the metabolism of lipoproteins, although the corresponding mechanisms are not clearly defined. OBJECTIVE To summarize the available data on the mechanisms linking incretins with the characteristics of serum lipoproteins and discuss the clinical implications of these relationships. METHODS PubMed was searched using the terms "incretins", "GLP-1", "GIP" and "lipids", "dyslipidemia", "triglycerides", "apolipoprotein B48". All articles published in the English language until June 2016 were assessed and the relevant information is presented here. RESULTS GLP-1, and therapies that increase its activity, exert a beneficial effect on lipoprotein metabolism that is translated in a reduction in the fasting and postprandial concentration of triglycerides and a small improvement in the concentration and function of HDLs. In addition, a shift towards larger, less atherogenic particles usually follows the administration of GLP-1 receptor agonists. The mechanisms that underlie these changes involve a direct effect of GLP- 1 on the hepatic and intestinal production of triglyceride-rich lipoproteins, the GLP-1 induced increase in the production and function of insulin, the activation of specific areas of central nervous system as well as the increase in the peripheral utilization of triglycerides for energy production. On the other hand, GLP-2 increases the absorption of dietary fat and the production of triglyceride-rich lipoproteins while the role of GIP on lipid metabolism remains indeterminate. CONCLUSION GLP-1 and incretin-based therapies favorably affect lipid metabolism. These effects may contribute to the beneficial effects of incretin-based therapies on atherosclerosis and fatty liver disease.
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7.
Altered glucose metabolism after bariatric surgery: What's GLP-1 got to do with it?
Smith, EP, Polanco, G, Yaqub, A, Salehi, M
Metabolism: clinical and experimental. 2018;:159-166
Abstract
Bariatric surgery is an effective treatment for obesity. The two widely performed weight-loss procedures, Roux-en-Y gastric bypass (GB) and sleeve gastrectomy (SG), alter postprandial glucose pattern and enhance gut hormone secretion immediately after surgery before significant weight loss. This weight-loss independent glycemic effects of GB has been attributed to an accelerated nutrient transit from stomach pouch to the gut and enhanced secretion of insulinotropic gut factors; in particular, glucagon-like peptide-1 (GLP-1). Meal-induced GLP-1 secretion is as much as tenfold higher in patients after GB compared to non-surgical individuals and inhibition of GLP-1 action during meals reduces postprandial hyperinsulinemia after GB two to three times more than that in persons without surgery. Moreover, in a subgroup of patients with the late complication of postprandial hyperinsulinemic hypoglycemia after GB, GLP1R blockade reverses hypoglycemia by reducing meal stimulated insulin secretion. The role of enteroinsular axis activity after SG, an increasingly popular alternative to GB, is less understood but, similar to GB, SG accelerates nutrient delivery to the intestine, improves glucose tolerance, and increases postprandial GLP-1 secretion. This review will focus on the current evidence for and against the role of GLP-1 on glycemic effects of GB and will also highlight differences between GB and SG.
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8.
Incretin hormones: Their role in health and disease.
Nauck, MA, Meier, JJ
Diabetes, obesity & metabolism. 2018;:5-21
Abstract
Incretin hormones are gut peptides that are secreted after nutrient intake and stimulate insulin secretion together with hyperglycaemia. GIP (glucose-dependent insulinotropic polypeptide) und GLP-1 (glucagon-like peptide-1) are the known incretin hormones from the upper (GIP, K cells) and lower (GLP-1, L cells) gut. Together, they are responsible for the incretin effect: a two- to three-fold higher insulin secretory response to oral as compared to intravenous glucose administration. In subjects with type 2 diabetes, this incretin effect is diminished or no longer present. This is the consequence of a substantially reduced effectiveness of GIP on the diabetic endocrine pancreas, and of the negligible physiological role of GLP-1 in mediating the incretin effect even in healthy subjects. However, the insulinotropic and glucagonostatic effects of GLP-1 are preserved in subjects with type 2 diabetes to the degree that pharmacological stimulation of GLP-1 receptors significantly reduces plasma glucose and improves glycaemic control. Thus, it has become a parent compound of incretin-based glucose-lowering medications (GLP-1 receptor agonists and inhibitors of dipeptidyl peptidase-4 or DPP-4). GLP-1, in addition, has multiple effects on various organ systems. Most relevant are a reduction in appetite and food intake, leading to weight loss in the long term. Since GLP-1 secretion from the gut seems to be impaired in obese subjects, this may even indicate a role in the pathophysiology of obesity. Along these lines, an increased secretion of GLP-1 induced by delivering nutrients to lower parts of the small intestines (rich in L cells) may be one factor (among others like peptide YY) explaining weight loss and improvements in glycaemic control after bariatric surgery (e.g., Roux-en-Y gastric bypass). GIP and GLP-1, originally characterized as incretin hormones, have additional effects in adipose cells, bone, and the cardiovascular system. Especially, the latter have received attention based on recent findings that GLP-1 receptor agonists such as liraglutide reduce cardiovascular events and prolong life in high-risk patients with type 2 diabetes. Thus, incretin hormones have an important role physiologically, namely they are involved in the pathophysiology of obesity and type 2 diabetes, and they have therapeutic potential that can be traced to well-characterized physiological effects.
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9.
Glucagon-like peptide 1 in health and disease.
Andersen, A, Lund, A, Knop, FK, Vilsbøll, T
Nature reviews. Endocrinology. 2018;(7):390-403
Abstract
In healthy individuals, the incretin hormone glucagon-like peptide 1 (GLP1) potentiates insulin release and suppresses glucagon secretion in response to the ingestion of nutrients. GLP1 also delays gastric emptying and increases satiety. In patients with type 2 diabetes mellitus (T2DM), supraphysiological doses of GLP1 normalize the endogenous insulin response during a hyperglycaemic clamp. Owing to the short plasma half-life of native GLP1, several GLP1 receptor agonists (GLP1RAs) with longer half-lives have been developed for the treatment of T2DM. These compounds vary in chemical structure, pharmacokinetics and size, which results in different clinical effects on hyperglycaemia and body weight loss; these variations might also explain the difference in cardiovascular effect observed in large-scale cardiovascular outcome trials, in which certain GLP1RAs were shown to have a positive effect on cardiovascular outcomes. Owing to their metabolic effects, GLP1RAs are also considered for the treatment of several other lifestyle-induced conditions, such as obesity, prediabetes and liver disease. This Review provides insights into the physiology of GLP1 and its involvement in the pathophysiology of T2DM and an overview of the currently available and emerging GLP1RAs. Furthermore, we review the results from the currently available large-scale cardiovascular outcome trials and the use of GLP1RAs for other indications.
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10.
[New antidiabetic drugs: current status and future prospects - a review of the literature].
Baranowska, A, Stefanowicz-Rutkowska, M, Matuszewski, W, Bandurska-Stankiewicz, E
Wiadomosci lekarskie (Warsaw, Poland : 1960). 2018;(8):1588-1598
Abstract
425 million people worldwide suffer from diabetes. In patients with diabetes, insufficient glycemic control is associated with a high risk of developing micro- and macrovascular complications. The last decade has significantly contributed to extending the range of therapeutic options in the treatment of type 2 diabetes with new drugs that mimic ormodulate physiological processes in the human body. The paper summarizes the most important conclusions regarding the use of four groups of new drugs: thiazolidinediones, analogues of glucagon-like peptide 1, dipeptidyl peptidase-4 inhibitors and glucose-sodium 2 glucose cotransporter inhibitors, based on a review of the latest literature. These drugs have an anti-hyperglycemic effect and have numerous beneficial pleiotropic effects, including a safe cardiovascular profile. However, many of the mechanisms of action and effects of therapy, including side effects, new antidiabetic drugs remain unclear and require further clinical trials.