Glucagon-like peptide 1 based therapy for type 2 diabetes.

BACKGROUND: Incidence of type 2 diabetes mellitus (T2DM) has increased in young people in recent years and new therapies are required for its effective treatment. Glucagon-like peptide 1 (GLP-1) is a potent blood glucose-lowering hormone produced in the L cells of the intestine. It may be potentially effective in the treatment of hyperglycemia in patients with T2DM. DATA SOURCES: PubMed database were searched with the terms "GLP-1", "incretins" and "diabetes". RESULTS: GLP-1 is a product of the glucagon gene, and its secretion is controlled by both neural and endocrine signals. GLP-1 lowers plasma glucose by stimulating insulin and suppressing secretion of glucagons, thus inhibiting gastric emptying and reducing appetite. GLP-1 exerts these actions by the engagement of structurally distinct G-protein-coupled receptors (GPCRs). In patients with T2DM, GLP-1 increases insulin secretion and normalizes both fasting and postprandial blood glucose when given as a continuous intravenous infusion. However, the native hormone is unsuitable as a drug because it is broken down rapidly by dipeptidyl peptidase IV (DPP-4) and cleared by the kidneys. Fortunately, many GLP-1 agonists or analogues and DPP-4 inhibitors have been found or developed, such as exendin-4, exenatide, liraglutide, CJC1131, vidaliptin and P32/98. Clinical trials have shown their therapeutic functions in T2DM with little adverse reaction. CONCLUSION: A GLP-1 based therapy will be safe and effective for the treatment of T2DM.

Exploiting the antidiabetic properties of incretins to treat type 2 diabetes mellitus: glucagon-like peptide 1 receptor agonists or insulin for patients with inadequate glycemic control?

Type 2 diabetes mellitus is associated with progressive decreases in pancreatic beta-cell function. Most patients thus require increasingly intensive treatment, including oral combination therapies followed by insulin. Fear of hypoglycemia is a potential barrier to treatment adherence and glycemic control, while weight gain can exacerbate hyperglycemia or insulin resistance. Administration of insulin can roughly mimic physiologic insulin secretion but does not address underlying pathophysiology. Glucagon-like peptide 1 (GLP-1) is an incretin hormone released by the gut in response to meal intake that helps to maintain glucose homeostasis through coordinated effects on islet alpha- and beta-cells, inhibiting glucagon output, and stimulating insulin secretion in a glucose-dependent manner. Biological effects of GLP-1 include slowing gastric emptying and decreasing appetite. Incretin mimetics (GLP-1 receptor agonists with more suitable pharmacokinetic properties versus GLP-1) significantly lower hemoglobin A1c, body weight, and postprandial glucose excursions in humans and significantly improve beta-cell function in vivo (animal data). These novel incretin-based therapies offer the potential to reduce body weight or prevent weight gain, although the durability of these effects and their potential long-term benefits need to be studied further. This article reviews recent clinical trials comparing therapy with the incretin mimetic exenatide to insulin in patients with oral treatment failure, identifies factors consistent with the use of each treatment, and delineates areas for future research.

[New oral antidiabetic agents--clinical perspectives]. / Neue orale Antidiabetika: Klinische Perspektiven.

In recent years new pharmacological agents have emerged, which enable us to widen the spectrum of diabetes management based on clear pathophysiological concepts. One should first of all mention the DPP4-inhibitors and the incretin mimetics, which have the potential of restoring the incretin effect in patients with type 2 diabetes mellitus. Moreover, it has been shown that the agent rimonabant, which was first used in order to achieve weight reduction, also contributed to the significant improvement of metabolic syndrome's parameters. Recent studies have shown that the dual alpha/gamma-PPAR-agonists have serious adverse effects. The thiazolidinediones (glitazones) significantly improve insulin sensitivity, diminish fat accumulation in the liver and increase circulating levels of adiponectin. Various adverse effects of glitazones have been described in recent studies. In the near future one should await the discovery of more oral antidiabetic agents acting through modulation of important enzymes in glucose metabolism and transport pathways.

New drugs for the treatment of diabetes: part II: Incretin-based therapy and beyond.

This is the second of a 2-part series focusing on newer therapies for type 2 diabetes and their cardiovascular implications. In the first segment, we reviewed the thiazolidinediones, highlighting emerging data concerning their cardiovascular effects, both positive and negative. Here, we present a corresponding discussion of the newest antihyperglycemic category, modulators of the incretin system, which include the glucagon-like peptide-1 mimetics and the dipeptidyl peptidase-4 inhibitors. In addition, we briefly survey several novel drug classes in development, provide summary recommendations for glucose-lowering regimens in specific patient types, underscore the importance of nonglucose cardiovascular risk reduction strategies, and comment on present and future considerations for the regulatory review of diabetes drugs.

Exenatide: new drug. Type 2 diabetes for some overweight patients.

(1) When type 2 diabetes is inadequately controlled with oral antidiabetic therapy, one option is to add subcutaneous insulin injections (or to accept less stringent glycaemic control). However, since the effects of adding insulin have only been evaluated in the short-term, effects on long-term clinical outcomes remain unknown. (2) Exenatide, a drug belonging to a new pharmacological class (incretin analogues), is marketed as a subcutaneously administered adjunct to inadequately effective oral antidiabetic therapy in adults with type 2 diabetes. (3) Three placebo-controlled trials lasting 7 months showed that adding exenatide to metformin and/or a glucose-lowering sulphonylurea yielded an HbA1c level of 7% or less in about 40% of patients treated with exenatide 10 micrograms twice a day, versus about 10% of patients on placebo. The potential impact of exenatide on morbidity and mortality is not known. (4) In two trials versus insulin glargine and in one trial versus insulin aspart (+ isophane insulin), exenatide was as effective as the various insulins in controlling HbA1c levels. (5) During clinical trials, patients receiving exenatide lost an average of about 2 kg after 6 months, while insulin was associated with a weight gain of about 2 kg. (6) There was a similar incidence of hypoglycaemia with exenatide and insulin. In patients treated with exenatide, concomitant use of glucose-lowering sulphonylurea increases the risk of hypoglycaemia. (7) More than half of patients on exenatide experienced nausea, versus fewer than 10% of patients on insulin glargine. (8) The long-term consequences of the presence of antiexenatide antibodies on the effectiveness of treatment are not known. (9) Exenatide is administered in two subcutaneous injections a day, at fixed doses. Insulin is administered in one or several injections a day, at doses adjusted to self-monitored blood glucose levels. (10) Adding insulin rather than exenatide is a better option in general when oral antidiabetic therapy fails in patients with type 2 diabetes, as we have more experience with insulin and there is no evidence of important advantages with exenatide. The latter should be reserved for situations in which weight gain is a major problem.