Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The incretins are peptide hormones produced by special cell types of the intestines, which are secreted following ingestion of foods, indirectly, through a complex mechanism, by decreasing postprandial blood glucose levels participate in the regulation of the glucose homeostasis. The article beside of summarizing the physiological aspects of the two most important incretins, the glucagon-like peptide (GLP)-1 and glucose-dependent insulinotrope polypeptide (GIP), gives a detailed overview of multifaceted effects of GLP-1 and their potential application in the therapy of type 2 diabetes mellitus. The human GLP-1 because of its very short half-life is not suitable for therapeutic use. However, by inhibition its degradation, by suppression of activity of the serine peptidase type enzyme dipeptidyl peptidase (DPP) IV, its effect can be prolonged. Compounds with this effect have been synthetised, as well as drugs resistant to DPP IV, not being identical with the structure of the human GLP-1, but having agonist effect on its receptor could also be manufactured. Members of the first group are called incretin (GLP-1) enhancers, while of the second one incretin mimetics. Two of the enhancers, the sita- and vildagliptin, and one representative of the incretin mimetics, the exenatide after encouraging preclinical and human experiences have also been registered and introduced in the clinical practice. Their potential place in the treatment of type 2 diabetes is not exactly outlined at present. Though there are arguments underlining their early use in the glucose lowering drug treatment of type 2 diabetes, their application as part of a combination therapy seems to be a real indication.
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PMID:[Incretin enhancers, incretin mimetics: from therapeutic concept to clinical application]. 1738 51

Dipeptidyl peptidase-4 (DPP-4) inhibitors represent a new class of oral antihyperglycemic agents to treat patients with type 2 diabetes. DPP-4 inhibitors improve fasting and postprandial glycemic control without hypoglycemia or weight gain. This article focuses on the physiology, clinical pharmacology, tolerability, and clinical utility of the DPP-4 inhibitor sitagliptin in the management of type 2 diabetes.
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PMID:Dipeptidyl peptidase-4 inhibitors for the treatment of type 2 diabetes: focus on sitagliptin. 1739 25

The hyperglycemic activity of pancreatic extracts was encountered some 80 yr ago during efforts to optimize methods for the purification of insulin. The hyperglycemic substance was named "glucagon," and it was subsequently determined that glucagon is a 29-amino acid peptide synthesized and released from pancreatic alpha-cells. This article begins with a brief overview of the discovery of glucagon and the contributions that somatostatin and a sensitive and selective assay for pancreatic (vs. gut) glucagon made to understanding the physiological and pathophysiological roles of glucagon. Studies utilizing these tools to establish the function of glucagon in normal nutrient homeostasis and to document a relative glucagon excess in type 2 diabetes mellitus (T2DM) and precursors thereof are then discussed. The evidence that glucagon excess contributes to the development and maintenance of fasting hyperglycemia and that failure to suppress glucagon secretion contributes to postprandial hyperglycemia is then reviewed. Although key human studies are emphasized, salient animal studies highlighting the importance of glucagon in normal and defective glucoregulation are also described. The past eight decades of research in this area have led to development of new therapeutic approaches to treating T2DM that have been shown to, or are expected to, improve glycemic control in patients with T2DM in part by improving alpha-cell function or by blocking glucagon action. Accordingly, this review ends with a discussion of the status and therapeutic potential of glucagon receptor antagonists, alpha-cell selective somatostatin agonists, glucagon-like peptide-1 agonists, and dipeptidyl peptidase-IV inhibitors. Our overall conclusions are that there is considerable evidence that relative hyperglucagonemia contributes to fasting and postprandial hyperglycemia in patients with T2DM, and there are several new and emerging pharmacotherapies that may improve glycemic control in part by ameliorating the hyperglycemic effects of this relative glucagon excess.
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PMID:The role of alpha-cell dysregulation in fasting and postprandial hyperglycemia in type 2 diabetes and therapeutic implications. 1740 88

Although there are numerous effective pharmacotherapeutic agents available to treat type 2 diabetes, 5% to 10% of the population with diabetes experience secondary failure. To help combat this issue, it is imperative that clinicians understand the limitations of some current therapies. Secondary failure can be due to decreasing beta cell function, poor adherence to treatment, weight gain, reduction of exercise, changes in diet, or illness. Glycemic control and cardiovascular risk reduction are of paramount concern; however, the nonglycemic effects of several new therapies to treat diabetes may be advantageous and positively affect the long-term cost of therapy. The discoveries of amylin and glucagonlike peptide-1 have furthered our understanding of the abnormalities involved in diabetes, enabling the development of additional therapeutic options. Incretin-based therapy, including incretin mimetics such as exenatide and the yet-to-be-approved dipeptidyl peptidase-4 inhibitors, and new basal and inhaled insulin may change the way we currently treat type 2 diabetes.
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PMID:New technologies and therapies in the management of diabetes. 1741 33

This randomized, open-label, placebo-controlled, 7-period crossover study assessed dose-response relationships following single oral doses (10-400 mg) of vildagliptin in 16 patients with type 2 diabetes mellitus. Plasma levels of parent drug, dipeptidyl peptidase-4 activity, glucose, insulin, and glucagon were measured during 75-g oral glucose tolerance tests performed after an overnight fast, 30 minutes after drug administration. The t(max) for parent drug was observed between 0.5 and 1.5 hours postdose. Both C(max) and AUC(0-8 h) increased dose proportionately. Both onset and duration of dipeptidyl peptidase-4 inhibition were dose dependent, but >90% inhibition occurred within 45 minutes and was maintained for >/=4 hours after each dose. Glucose excursions and glucagon levels during oral glucose tolerance tests were significantly and similarly decreased after each dose of vildagliptin, and insulin levels were significantly and similarly increased after each dose level. Unlike findings during mixed-meal challenges, vildagliptin increases plasma insulin levels during oral glucose tolerance tests in patients with type 2 diabetes mellitus.
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PMID:Pharmacodynamics of vildagliptin in patients with type 2 diabetes during OGTT. 1744 88

Type 2 diabetes mellitus affects 9.6% of the adults in the United States and more than 200 million people worldwide. Diabetes can be a devastating disease, but it can now be treated with nine classes of approved drugs (insulins, sulfonylureas, glinides, biguanides, alpha-glucosidase inhibitors, thiazolidinediones, glucagon-like peptide 1 mimetics, amylin mimetics, and dipeptidyl peptidase 4 inhibitors), in addition to diet and exercise regimens. Choosing which drug to give a patient is based on efficacy and also availability, cost, safety, tolerability, and convenience. Personalized medicine promises a path for individually optimized treatment choices, but realizing this promise will require a more comprehensive characterization of disease and drug response. In this issue of the JCI, Shu et al. make significant progress by integrating diverse data supporting the hypothesis that genetic variation in organic cation transporter 1 (OCT1) affects the response to the widely used biguanide metformin (see the related article beginning on page 1422). We discuss metformin, OCT1, pharmacogenetics, and how the integrative genomics revolution is likely to change our understanding and treatment of diabetes.
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PMID:Pharmacogenetics of metformin response: a step in the path toward personalized medicine. 1747 61

Inhibition of dipeptidyl peptidase-4 (DPP-4) is currently explored as a novel therapy of type 2 diabetes. The strategy has been shown to improve glycemia in most, but not all, rodent forms of glucose intolerance. In this study, we explored the effects of DPP-4 inhibition in mice with beta-cell overexpression of human islet amyloid polypeptide (IAPP). We therefore administered the orally active and highly selective DPP-4 inhibitor, vildagliptin (3 micromol/mouse daily) to female mice with beta-cell overexpression of human IAPP. Controls were given plain water, and a series of untreated wildtype mice was also included. After five weeks, an intravenous glucose tolerance test showed improved glucose disposal and a markedly enhanced insulin response in mice treated with vildagliptin. After eight weeks, a gastric tolerance test showed that vildagliptin improved glucose tolerance and markedly (approximately ten-fold) augmented the insulin response in association with augmented (approximately five-fold) levels of intact glucagon-like peptide-1 (GLP-1). Furthermore, after nine weeks, islets were isolated. Islets from vildagliptin-treated mice showed augmented glucose-stimulated insulin response and a normalization of the islet insulin content, which was reduced by approximately 50% in transgenic controls versus wildtype animals. Double immunostaining of pancreatic islets for insulin and glucagon revealed that transgenic islets displayed severely disturbed intra-islet topography with frequently observed centrally located alpha-cells. Treatment with vildagliptin restored the islet topography. We therefore conclude that DPP-4 inhibition improves islet function and islet topography in mice with beta-cell specific transgenic overexpression of human IAPP.
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PMID:DPP-4 inhibition improves glucose tolerance and increases insulin and GLP-1 responses to gastric glucose in association with normalized islet topography in mice with beta-cell-specific overexpression of human islet amyloid polypeptide. 1748 89

This review focuses on the mechanisms regulating the synthesis, secretion, biological actions, and therapeutic relevance of the incretin peptides glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). The published literature was reviewed, with emphasis on recent advances in our understanding of the biology of GIP and GLP-1. GIP and GLP-1 are both secreted within minutes of nutrient ingestion and facilitate the rapid disposal of ingested nutrients. Both peptides share common actions on islet beta-cells acting through structurally distinct yet related receptors. Incretin-receptor activation leads to glucose-dependent insulin secretion, induction of beta-cell proliferation, and enhanced resistance to apoptosis. GIP also promotes energy storage via direct actions on adipose tissue, and enhances bone formation via stimulation of osteoblast proliferation and inhibition of apoptosis. In contrast, GLP-1 exerts glucoregulatory actions via slowing of gastric emptying and glucose-dependent inhibition of glucagon secretion. GLP-1 also promotes satiety and sustained GLP-1-receptor activation is associated with weight loss in both preclinical and clinical studies. The rapid degradation of both GIP and GLP-1 by the enzyme dipeptidyl peptidase-4 has led to the development of degradation-resistant GLP-1-receptor agonists and dipeptidyl peptidase-4 inhibitors for the treatment of type 2 diabetes. These agents decrease hemoglobin A1c (HbA1c) safely without weight gain in subjects with type 2 diabetes. GLP-1 and GIP integrate nutrient-derived signals to control food intake, energy absorption, and assimilation. Recently approved therapeutic agents based on potentiation of incretin action provide new physiologically based approaches for the treatment of type 2 diabetes.
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PMID:Biology of incretins: GLP-1 and GIP. 1749 8

The increasing prevalence of diabetes worldwide is cause for concern both in terms of associated morbidity and increasing health costs. This review aims to focus on new and emerging treatments for type 1 and type 2 diabetes. There has been recent focus on diabetes prevention both for type 1 and type 2 diabetes. Prevention programme including lifestyle measures and oral hypoglycaemic agents have shown up to 61% reduction in the development of type 2 diabetes in patients with impaired glucose tolerance or impaired fasting glucose. Little progress has been made to date on type 1 diabetes prevention although current work is focusing on T-cell immunomodulation therapy and beta cell regeneration. Management of type 2 diabetes has been improved by the recent introduction of the peroxisome proliferator-activated receptor-gamma agonists and more recently by the incretins including glucagons like peptide analogues and dipeptidyl peptidase-4 inhibitors. This article focuses on the benefits and restrictions of these new agents. The new insulin analogues glargine and detemir have made significant improvements in the management of type 1 diabetes both in terms of improvement in glycaemic control and in reducing hypoglycaemia rates. Inhaled insulin also shows promise for needle-free treatment of diabetes and these insulins are currently undergoing phase 3 trials. Insulin infusion pumps are becoming more sophisticated and increasingly popular in the management of type 1 diabetes. Many studies have shown benefits for improved glycaemic control and reduced rates of hypoglycaemia with pump treatment compared with multiple daily injections. Pancreas and islet cell transplantation are the subject of ongoing research, but currently require immunosuppressive treatment regimes. The main limitation is lack of availability of donor pancreases. There is much hope that new treatments outlined in this review will result in improved outcomes in the treatment of diabetes.
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PMID:Diabetes: advances in treatment. 1753 82

Sitagliptin is a highly selective orally active dipeptidyl peptidase-4 inhibitor recently approved in the United States for the treatment of type 2 diabetes. Ten healthy subjects received single oral doses of 25, 50, 100, 200 and 400 mg final market image tablets in five separate treatment periods in randomized fashion to assess dose proportionality. Blood (up to 72 h post-dose) and urine (up to 24 h post-dose) samples for sitagliptin pharmacokinetic analysis were collected at pre-specified times following administration of sitagliptin. Dose-proportionality of AUC(0-infinity), C(max) and C(24 h) was assessed using a power-law model. The results of this study indicate that plasma AUC(0-infinity) increased in a dose-proportional manner over the 25-400 mg dose range. Over the same dose range, plasma C(max) increased in a greater than dose-proportional manner and C(24 h) increased in a modestly less than dose proportional manner. No clinically meaningful differences in T(max) or apparent t(1/2) were noted across the dose range. Differences in the percentage of the sitagliptin dose excreted unchanged in urine (72.5% pooled across doses) and renal clearance (344 ml/min pooled across doses) were not statistically significant. Sitagliptin was generally well tolerated at all the doses evaluated.
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PMID:Dose-proportionality of a final market image sitagliptin formulation, an oral dipeptidyl peptidase-4 inhibitor, in healthy volunteers. 1757 Dec 84


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