| 1. |
- Ahrén, Bo
(författare)
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DPP-4 inhibition and islet function
- 2012
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Ingår i: Journal of Diabetes Investigation. - : Wiley. - 2040-1116. ; 3:1, s. 3-10
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Forskningsöversikt (refereegranskat)abstract
- During recent years, dipeptidyl peptidase-4 (DPP-4) inhibition has been included in the clinical management of type 2 diabetes, both as monotherapy and as add-on to several other therapies. DPP-4 inhibition prevents the inactivation of the incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). This results in stimulation of insulin secretion and inhibition of glucagon secretion, and there is also a potential beta-cell preservation effect, as judged from rodent studies; that is, it might target the key islet dysfunction in the disease. In type 2 diabetes. This reduces 24-h glucose levels and reduces HbA1c by approximate to 0.81.1% from baseline levels of 7.78.5%. DPP-4 inhibition is safe, with a very low risk for adverse events including hypoglycemia, and it prevents weight gain. The present review summarizes the studies on the influence of DPP-4 inhibition on islet function. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00184.x, 2012)
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| 2. |
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| 3. |
- Ahrén, Bo
(författare)
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GLP-1 and extra-islet effects.
- 2004
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 1439-4286 .- 0018-5043. ; 36:11-12, s. 842-845
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Forskningsöversikt (refereegranskat)
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| 4. |
- Ahrén, Bo
(författare)
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GLP-1 for type 2 diabetes
- 2011
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 317:9, s. 1239-1245
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Forskningsöversikt (refereegranskat)abstract
- Glucagon-like peptide-1 (GLP-1)-based therapy of type 2 diabetes is executed either by GLP-1 receptor agonists, which stimulate the GLP-1 receptors, or by dipeptidyl peptidase-4 (DPP-4) inhibitors, which prevent the inactivation of endogenous GLP-1 thereby increasing the concentration of endogenous active GLP-1. GLP-1 activates pancreatic receptors resulting in improved glycemia through glucose-dependent stimulation of insulin secretion and inhibition of glucagon secretion. There is also a potential beta cell preservation effect, as judged from rodent studies. GLP-1 receptors are additionally expressed in extrapancreatic tissue, having potential for the treatment to reduce body weight and to potentially have beneficial cardio- and endothelioprotective effects. Clinical trials in subjects with type 2 diabetes have shown that in periods of 12 weeks or more, these treatments reduce HbA1c by approximate to 0.8-1.1% from baseline levels of 7.7-8.5%, and they are efficient both as monotherapy and in combination therapy with metformin, sulfonylureas, thiazolidinediones or insulin. Furthermore, GLP-1 receptor agonists reduce body weight, whereas DPP-4 inhibitors are body weight neutral. The treatment is safe with very low risk for adverse events, including hypoglycaemia. GLP-1 based therapy is thus a novel and now well established therapy of type 2 diabetes, with a particular value in combination with metformin in patients who are inadequately controlled by metformin alone. (C) 2011 Elsevier Inc. All rights reserved.
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| 5. |
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| 6. |
- Ahrén, Bo
(författare)
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Glucagon-early breakthroughs and recent discoveries.
- 2015
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Ingår i: Peptides. - : Elsevier BV. - 1873-5169 .- 0196-9781. ; 67, s. 74-81
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Forskningsöversikt (refereegranskat)abstract
- Glucagon was discovered in 1922 as a hyperglycemic factor in the pancreas. During its early history up to 1970, glucagon was shown to increase circulating glucose through stimulating glycogenolysis in the liver. It was also shown to be a constituent of islet non-ß cells and to signal through G protein coupled receptors and cyclic AMP. Furthermore, its chemical characteristics, including amino acid sequence, and its processing from the preproglucagon gene had been established. During the modern research during the last 40 years, glucagon has been established as a key hormone in the regulation of glucose homeostasis, including a key role for the glucose counterregulation to hypoglycemia and for development of type 2 diabetes, and today glucagon is a potential target for treatment of the disease. Glucagon has also been shown to be a key factor beyond glucose control and involved in many processes. For the coming, future research, studies will be focused on α-cell biology beyond glucagon, hyperglucagonemia in other conditions than diabetes, its involvement in the regulation of body weight and energy expenditure and the potential of glucagon as a target for other diseases than type 2 diabetes, such as type 1 diabetes and obesity. This review summarizes the more than 90 years history of this important hormone as well as discusses potential future research regarding glucagon.
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| 7. |
- Ahrén, Bo, et al.
(författare)
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Glucose effectiveness : Lessons from studies on insulin-independent glucose clearance in mice
- 2021
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Ingår i: Journal of Diabetes Investigation. - : Wiley. - 2040-1116 .- 2040-1124. ; 12:5, s. 675-685
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Forskningsöversikt (refereegranskat)abstract
- Besides insulin-mediated transport of glucose into the cells, an important role is also played by the non-insulin-mediated transport. This latter process is called glucose effectiveness (acronym SG), which is estimated by modeling of glucose and insulin data after an intravenous glucose administration, and accounts for ≈70% of glucose disposal. This review summarizes studies on SG, mainly in humans and rodents with focus on results achieved in model experiments in mice. In humans, SG is reduced in type 2 diabetes, in obesity, in liver cirrhosis and in some elderly populations. In model experiments in mice, SG is independent from glucose levels, but increases when insulin secretion is stimulated, such as after administration of the incretin hormones, glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide. SG is reduced in insulin resistance induced by high-fat feeding and by exogenous administration of glucagon. Glucose-dependent (insulin-independent) glucose disposal is therefore important for glucose elimination, and it is also well regulated. It might be of pathophysiological relevance for the development of type 2 diabetes, in particular during insulin resistance, and might also be a target for glucose-reducing therapy. Measuring SG is essentially important when carrying out metabolic studies to understand glucose homeostasis.
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| 8. |
- Ahrén, Bo
(författare)
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Glucose-lowering action through targeting islet dysfunction in type 2 diabetes : Focus on dipeptidyl peptidase-4 inhibition
- 2021
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Ingår i: Journal of Diabetes Investigation. - : Wiley. - 2040-1116 .- 2040-1124. ; 12:7, s. 1128-1135
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Forskningsöversikt (refereegranskat)abstract
- Dipeptidyl peptidase-4 (DPP-4) inhibition is a glucose-lowering medication for type 2 diabetes. It works through stimulation of insulin secretion and inhibition of glucagon secretion in a glucose-dependent manner, resulting in lowered fasting and postprandial glycemia with low risk of hypoglycemia. As impaired insulin secretion and augmented glucagon secretion are key factors underlying hyperglycemia in type 2 diabetes, DPP-4 inhibition represents a therapy that targets the underlying mechanisms of the disease. If insufficient in monotherapy, it can preferably be used in combination with metformin, which targets insulin resistance, and also in combination with sodium–glucose cotransporter 2 inhibition, thiazolidinediones and insulin, which target other mechanisms. In individuals of East Asian origin, islet dysfunction is of particular importance for the development of type 2 diabetes. Consequently, it has been shown in several studies that DPP-4 is efficient in these populations. This mini-review highlights the islet mechanisms of DPP-4 inhibition, islet dysfunction as a key factor for hyperglycemia in type 2 diabetes and that, consequently, DPP-4 is of particular value in populations where islet dysfunction is central, such as in individuals of East Asian origin.
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| 9. |
- Ahrén, Bo, et al.
(författare)
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Importance of quantifying insulin secretion in relation to insulin sensitivity to accurately assess beta cell function in clinical studies.
- 2004
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Ingår i: European Journal of Endocrinology. - : Oxford University Press (OUP). - 1479-683X .- 0804-4643. ; 150:2, s. 97-104
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Forskningsöversikt (refereegranskat)abstract
- Insulin sensitivity and insulin secretion are mutually related such that insulin resistance is compensated by increased insulin secretion. A correct judgement of insulin secretion therefore requires validation in relation to the insulin sensitivity in the same subject. Mathematical analyses of the relationship between insulin sensitivity and insulin secretion has revealed a hyperbolic function, such that the product of the two variables is constant. This product is usually called the disposition index. Several techniques may be used for its estimation such as data derived from the frequently sampled i.v. glucose tolerance test, the oral glucose tolerance test or the glucose-dependent arginine stimulation test or the euglycemic hyperinsulinemic clamp technique in combination with a test on insulin secretion. Using these techniques the compensatory increase in beta cell function in insulin resistance has been verified in obesity, in pregnancy and after glucocorticoid administration as has the defective beta cell function as the underlying cause of impaired glucose tolerance and type 2 diabetes. Similarly, combined analysis of insulin sensitivity and insulin secretion has shown a down-regulation of beta cell function in increased insulin sensitivity accompanying weight reduction in obesity and following exercise. Acknowledging this inverse relationship between insulin secretion and insulin sensitivity therefore requires estimation of both variables for correct assessment in any individual.
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| 10. |
- Ahrén, Bo
(författare)
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Incretin dysfunction in type 2 diabetes: Clinical impact and future perspectives.
- 2013
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Ingår i: Diabetes & Metabolism. - : Elsevier BV. - 1878-1780 .- 1262-3636. ; 39:3, s. 195-201
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Forskningsöversikt (refereegranskat)abstract
- The incretin effect refers to the augmentation of insulin secretion after oral administration of glucose compared with intravenous glucose administration at matched glucose levels. The incretin effect is largely due to the release and action on beta-cells of the gut hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). This system has in recent years had considerable interest due to the success of incretin therapy as a glucose-lowering strategy in type 2 diabetes. In non-diabetic subjects, the incretin effect is responsible for 50-70% of insulin release during oral glucose administration. In type 2 diabetes patients, the incretin effect is impaired and contributes to only 20-35% of the insulin response to oral glucose. The reason for the defective incretin effect in type 2 diabetes has been the subject of many studies. Although the reports in the literature are mixed, most studies of GIP and GLP-1 secretory responses to oral glucose or a mixed meal have shown fairly normal results in type 2 diabetes. In contrast, the insulinotropic effects of both GIP and GLP-1 are impaired in type 2 diabetes with greater suppression of insulin secretion augmentation with GIP than with GLP-1. The suggested causes of these defects are a defective beta-cell receptor expression or post-receptor defects secondary to the diabetes milieu, defective beta-cell function in general resulting in defective incretin effect and genetic factors initiating incretin hormone resistance. Identifying the mechanisms in greater detail would be important for understanding the strengths, weaknesses and efficacy of incretin therapy in individual patients to more specifically target this glucose-lowering therapy.
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