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 emergence of glucagon-like peptide 1 (GLP-1) as a well validated approach to the treatment of type 2 diabetes and preclinical validation of dipeptidyl peptidase IV (DPP-4) inhibition as an alternate, oral approach to GLP-1 therapy prompted the initiation of a DPP-4 inhibitor program at Merck in 1999. DPP-4 inhibitors threo- and allo-isoleucyl thiazolidide were in-licensed to jump start the program; however, development was discontinued due to profound toxicity in rat and dog safety studies. The observation that both compounds inhibit the related proline peptidases DPP8 and DPP9 led to the hypothesis that inhibition of DPP8 and/or DPP9 could evoke severe toxicities in preclinical species. Indeed, the observed toxicities were recapitulated with a selective dual DPP8/9 inhibitor but not with an inhibitor selective for DPP-4. Thus, medicinal chemistry efforts focused on identifying a highly selective DPP-4 inibitor for clinical development. Initial work in an alpha-amino acid series related to isoleucyl thiazolidide was discontinued due to lack of selectivity; however, SAR studies on two screening leads led to the identification of a highly selective beta-amino acid piperazine series. In an effort to stabilize the piperazine moiety, which was extensively metabolized in vivo, a series of bicyclic derivatives were prepared, culminating in the identification of a potent and selective triazolopiperazine series. Unlike their monocyclic counterparts, these analogs typically showed excellent pharmacokinetic properties in preclinical species. Optimization of this series led to the discovery of JANUVIA (sitagliptin), a highly selective DPP-4 inhibitor for the treatment of type 2 diabetes.
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PMID:Discovery of JANUVIA (Sitagliptin), a selective dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes. 1735 77

Cyanopyrrolidines (cyanopyrrolidides, pyrrolidine-2-nitriles, prolinenitriles) as inhibitors of the serine protease dipeptidyl peptidase IV (DPP-IV, DP IV, CD26, EC 3.4.14.5) were first reported in 1995. The interest in this compound class grew immensely when DPP-IV was discovered as a target for the treatment of type 2 diabetes. The research on cyanopyrrolidines cumulated in the discoveries of vildagliptin (LAF237, NVP-LAF237) and saxagliptin (BMS-477118). These compounds entered Phase III clinical trials in 2004 and 2005, respectively, and an application for market approval has been filed for vildagliptin in 2006. Today cyanopyrrolidines are, as judged by the numbers of patent applications, the most prominent of several series of DPP-IV inhibitors, and have the potential to become valuable medicines for type 2 diabetes in the near future. This review summarizes some historical aspects of the discovery of cyanopyrrolidine DPP-IV inhibitors, and then focuses mainly on structure-activity-relationships, the evolution of different subseries, the possibilities to improve on the chemical instability that is associated with this compound class, and on the discoveries of vildagliptin and saxagliptin. Within this context, the properties of individual compounds and results from biological studies are discussed. The rationale of DPP-IV inhibition, clinical data, and the relevance of selectivity over related proteases are extensively reviewed in other contributions to this issue of Curr. Top. Med. Chem., and are therefore only very briefly touched.
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PMID:11 Years of cyanopyrrolidines as DPP-IV inhibitors. 1735 79

This article describes how the discovery of a protein almost 100 years ago led to a clinical treatment for type 2 diabetes. Food intake, but also stimulation of the sympathetic nervous system (for example physical exercise), stimulates the secretion of glucagon-like-peptide-1 (GLP-1), derived from the glucagon precursor proglucagon in the small intestine. GLP-1 stimulates the production and secretion of insulin, the release of somatostatin, glucose utilisation by increasing insulin sensitivity and in animal studies also beta-cell function and expansion (proliferation). It inhibits glucagon release, gastric emptying, appetite and food intake via the central nervous system and in animal experiments also apoptosis of beta-cells. Since GLP-1 has to be administered parenterally and its half-life is short, a long-acting GLP-1 receptor agonist (exenatide) and a long-acting GLP-1 analogue (liraglutide) have been developed as well as an inhibitor of DPP-IV (the enzyme that breaks down endogenous GLP-1). Clinical studies with exenatide and liraglutide as monotherapy show a significant increase in the postprandial insulin concentration as well as a smaller increase in the postprandial glucose values. Adding these drugs to standard oral glucose-lowering medication shows improvement in glucose and insulin concentrations and HbA1c compared with adding placebo. The effect of exenatide on HbA1c is the same as adding a long-acting insulin analogue (glargine), but the increase in weight after adding insulin is not seen after exenatide, where even a small decrease in weight is found. This is an important advantage, because most type 2 patients are already obese. Whether less beta-cell apoptosis and maintenance of beta-cell function occurs, as has been shown in animal studies, has to be awaited. Clinical studies with the oral DPPIV inhibitors sitagliptin and vildagliptin show promising results, but are only published as abstracts at scientific meetings.
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PMID:Incretins: a new treatment option for type 2 diabetes? 1737 30

High energy-intake is a major factor revolved in type 2 diabetes. A number of animal models have been adopted for studying the type 2 diabetes, but they differ greatly from human type 2 diabetes. The objectives of the present study are to set up a suitable animal model, which is similar to the human type 2 diabetes, and then to understand possible molecular mechanisms underlying type 2 diabetes. Twenty five-week-old Wistar male rats were randomized into four groups. One group was fed with basal diet (BD) whereas the others consumed high-energy diet (HD) of 20% sucrose and 10% lard. Four weeks later, BD and one of HD were sampled. Other groups continued to consume HD, but one of them was treated by one injection of streptozotocin (STZ) (30 mg/kg body weight). After another four weeks, all were sacrificed. Changes in body weight were recorded, and levels of glucose, TG, TC, LDL in serum were analyzed by standard methods. Moreover, expressions of genes related to energy metabolism in liver, muscle and fat were measured by real-time RT-PCR. HD had no notable differentiation with BD on bodyweight and serum indices, but it altered gene expressions in a tissue-specific manner. Two receptors of adiponectin, leptin, PPARgamma, UCP2 mRNA levels in fat were up regulated, whereas most of them were down regulated in liver. STZ treatment induced symptoms of diabetes, and the gene expression mentioned above exhibited changes in both tissue- and gene-specific manners. The results suggest that a combination of low dose STZ and high-energy intake can effectively induce type 2 diabetes by altering the related gene expressions in major metabolic tissues.
Asia Pac J Clin Nutr 2007
PMID:Low dose streptozotocin (STZ) combined with high energy intake can effectively induce type 2 diabetes through altering the related gene expression. 1739 41

Trigonella foenum-graecum (fenugreek) seeds have previously been shown to have hypoglycemic and hypocholesterolemic effects on type 1 and type 2 diabetes mellitus patients and experimental diabetic animals. The Trigonella foenum-graecum extract has now been investigated for its effects on general properties, blood glucose and blood lipid, and hemorheological parameters in experimental diabetic rats. Streptozotocin-induced diabetic rats were administrated by oral intragastric intubation separately with low dose (0.44 g/kg.d), middle dose (0.87 g/kg.d), high dose (1.74 g/kg.d) of Trigonella foenum-graecum extract, and Metformin HCl (0.175 g/kg.d) for 6 weeks. Compared with diabetic group, rats treated with Trigonella foenum-graecum extract had an increase in body weight and a decrease in kidney /body weight ratio (p<0.05). Compared with diabetic group, rats treated Trigonella foenum-graecum extract had lower blood glucose, glycated hemoglobin, triglycerides, total cholestrol and higher higher-density-lipoprotein-cholesterol in a dose-dependent manner (p<0.05). The plasma viscosity, whole blood viscosity of high shear rate (200 s-1) and low shear rate (40 s-1), erythrocyte sedimentation rate, whole blood reduction viscosity and platelet conglutination were significantly reduced in diabetic rats treated with high and middle doses of Trigonella foenum-graecum extract, but not in those treated with low dose of Trigonella foenum-graecum extract. It may be concluded that Trigonella foenum-graecum extract can lower kidney /body weight ratio, blood glucose, blood lipid levels and improve hemorheological properties in experimental diabetic rats following repeated treatment for 6 weeks.
Asia Pac J Clin Nutr 2007
PMID:Effect of Trigonella foenum-graecum (fenugreek) extract on blood glucose, blood lipid and hemorheological properties in streptozotocin-induced diabetic rats. 1739 43

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

Alogliptin is a potent, selective inhibitor of the serine protease dipeptidyl peptidase IV (DPP-4). Herein, we describe the structure-based design and optimization of alogliptin and related quinazolinone-based DPP-4 inhibitors. Following an oral dose, these noncovalent inhibitors provide sustained reduction of plasma DPP-4 activity and a lowering of blood glucose in animal models of diabetes. Alogliptin is currently undergoing phase III trials in patients with type 2 diabetes.
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PMID:Discovery of alogliptin: a potent, selective, bioavailable, and efficacious inhibitor of dipeptidyl peptidase IV. 1744 5

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 article gives an overview of two recent trials investigating rosiglitazone, a thiazolidinedione, in its potential to prevent type 2 diabetes (T2D) and in its effectiveness in monotherapy. Thiazolidinediones are among the most important developments of recent years for combating T2D and therefore worth to revisit. The possible influence of thiazolidines in improving beta-cell function is discussed as well as the potential effects on insulin resistance and obesity. Novel, incretin-based therapies (GLP-1 analogues and DPP-4 inhibitors) and their effects on beta-cell function and beta-cell mass are also summarized and critically evaluated.
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PMID:The fate of Beta-cells in type 2 diabetes and the possible role of pharmacological interventions. 1748 46

Orally ingested glucose leads to a greater insulin response compared to intravenously administered glucose leading to identical postprandial plasma glucose excursions, a phenomenon referred to as the "incretin effect". The incretin effect comprises up to 60% of the postprandial insulin secretion and is diminished in type 2 diabetes. One of the very important gastrointestinal hormones promoting this effect is glucagon-like peptide 1 (GLP-1). It only stimulates insulin secretion and normalizes blood glucose in humans under hyperglycemic conditions, therefore it does not cause hypoglycemia. Other important physiological actions of GLP-1 are the inhibition of glucagon secretion and gastric emptying. It further acts as a neurotransmitter in the hypothalamus stimulating satiety. In vitro and animal data demonstrated that GLP-1 increases beta-cell mass by stimulating islet cell neogenesis and by inhibiting apoptosis of islets. In humans, the improvement of beta-cell function can be indirectly observed from the increased insulin secretory capacity after GLP-1 infusions. GLP-1 represents an attractive therapeutic principle for type 2 diabetes. However, native GLP-1 is degraded rapidly upon exogenous administration and is therefore not feasible for routine therapy. The first long-acting GLP-1 analog ("incretin mimetic") Exenatide (Byetta) has just been approved for type 2 diabetes therapy. Other compounds are being investigated in clinical trials (e.g. liraglutide, CJC1131). Dipeptidyl-peptidase IV inhibitors (DPP-IV inhibitors; e.g. Vildagliptin, Sitagliptin) that inhibit the enzyme responsible for incretin degradation are also under study.
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PMID:New therapeutic strategies for the treatment of type 2 diabetes mellitus based on incretins. 1749 80


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