ΙΝΚΡΕΤΙΝΕΣ : Ο ρόλος του ενζύμου DPP-4 στον Σακχαρώδη Διαβήτη τύπου 2

Παρουσίαση με θέμα: "ΙΝΚΡΕΤΙΝΕΣ : Ο ρόλος του ενζύμου DPP-4 στον Σακχαρώδη Διαβήτη τύπου 2"— Μεταγράφημα παρουσίασης:

1 ΙΝΚΡΕΤΙΝΕΣ : Ο ρόλος του ενζύμου DPP-4 στον Σακχαρώδη Διαβήτη τύπου 2
Δρ Ασημίνα Μητράκου Slide 1

2 Εκκριση Ινσουλίνης μετά την λήψη τροφής
Νευρογενή Ερεθίσματα Sympathetic innervation (β-receptors) Parasympathetic (cholinergic) innervation Γλυκόζη (κι αλλες ουσίες) ΙΝΣΟΥΛΙΝΗ Slide 3 The regulation of meal-induced insulin secretion is complex. It involves not only the direct effects of absorbed glucose and other substrates, but also the autonomic nervous system and hormones, known as “incretins”, released from the gastrointestinal tract. ΙΝΚΡΕΤΙΝΕΣ

3 Blood Glucose Plasma Insulin
Βασική παρατήρηση: Η έκκριση ινσουλίνης ειναι μεγαλύτερη μετα τηαν απο του στόματος λήψη γλυκόζης Blood Glucose Plasma Insulin Slide 4 These findings are representative of a number of studies performed shortly after it became possible to measure circulating insulin levels. In this case healthy volunteers were given identical amounts of glucose either intravenously or into the jejunum. While higher glucose concentrations were observed during IV infusion, the insulin response was greater during intrajejunal infusion. Observations such as these suggested that a circulating factor was released from the jejunum during glucose absorption and acted in concert with glucose to stimulate insulin release. The putative gut hormones were termed “incretins”1 and their actions to augment glucose-stimulated insulin release were termed “the incretin effect.”2 1Zunz E, LeBarre J. Arch Int Physiol Biochim. 1929:31:20-44. 2Creutzfeldt W. Diabetologia. 1979;16:75-85. McIntyre N, et al. Lancet. 1964;II:20-1.

4 Oral Glucose Tolerance Test
Φαινόμενο Ινκρετίνης Oral Glucose Tolerance Test Glucose (mg/dL) Insulin (pmol/L) 50 g glucose Slide 5 This and the subsequent slide illustrate the usual method of measuring the “incretin effect” in an experimental setting. Depicted here are the plasma glucose and insulin levels following a 50 g oral glucose load in healthy volunteers, the first step of a two day assessment. Nauck MA, et al. J Clin Endocrinol Metab. 1986;63:492-8.

5 OGTT and Matched IV Infusion
Φαινόμενο Ινκρετίνης OGTT and Matched IV Infusion Glucose (mg/dL) Insulin (pmol/L) Slide 6 As the second step in measuring the incretin effect, glucose is infused intravenously at a variable rate to reproduce the arterial glucose profile observed after the 50 g oral glucose load. This slide superimposes the glucose and insulin profiles during IV and oral glucose administration. The difference between the insulin curves during the oral and IV glucose loads is attributed to non-glycemic -cell stimuli and taken as a measure of the “incretin effect.” Nauck MA, et al. J Clin Endocrinol Metab. 1986;63:492-8.

6 Ορισμός της Ινκρετίνης
Εκκρινεται κατα την απορόφηση τροφής Αυξάνει την έκκριση ινσουλίνης Οι ινσουλινοτρόπος δράση τους είναι γλυκοζοεξαρτωμένη Slide 7 This slide lists defining characteristics of an incretin. Creutzfeldt Wl. Diabetologia. 1979;16:75-85.

7 Εκκριση Ινσουλίνης και επίπεδα γλυκόζης με αυξανομένη δόση γλυκόζης απο του στόματος/ενδοφλεβίως
Oral IV Slide 8 This slide compares the glucose levels and insulin secretory rates following oral or IV administration of 25 and 100 g glucose in healthy volunteers. The important points are that a) the period of hyperglycemia is shorter when glucose is ingested; b) the difference in the glucose excursion between the 25 and 100 g tests is much smaller following oral compared to IV glucose; c) the insulin response is more rapid and left-shifted during the OGT, and actually precedes the glucose peak. During IV glucose the insulin response follows plasma glucose. Tillil H, et al. Am J Physiol. 1988;254:E349-E357.

8 Η εκκριση των Ινκρετινών εξαρτάται απο το μεγεθος του γεύματος
Η εκκριση των Ινκρετινών εξαρτάται απο το μεγεθος του γεύματος GLP-1 GIP Slide 12 This slide depicts total GLP-1 and GIP immunoreactivity (measured with a C-terminally directed antibodies that recognize both the intact incretins and their metabolites) following a small (260 kcal) or large (520 kcal) breakfast meal in healthy volunteers. Both gut hormones are released promptly in response to nutrient ingestion in amounts that are proportional to the meal size. Plasma GLP-1 levels increase by 2-3 fold within 30 minutes of meal ingestion. Plasma GIP is elevated ~ 10 fold after the meal. Vilsbøll T, et al. J Clin Endocrinol Metab. 2003;88:

9 Οι ΙΝΚΡΕΤΙΝΕΣ GLP-1: Glucagon-Like Peptide–1 A G F S V S L G H E A T T
Y E Q A K K L A F R V W I E G G GIP: Glucose-Dependent Insulinotropic Peptide A G F S Y I M K H Y E T I D S A D I Q N Q D K G A N K L F W K V Q L W D Slide 9 This slide represents the amino acid sequences of glucagon-like peptide–1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). Both hormones are from the Secretin-Glucagon family of peptides. The amino acid residues shown in gold are those shared with the structure of glucagon. The second and third amino acids shown in red represent alanine and glutamate, the site at which the enzyme, dipeptidyl peptidase–IV (DPP-4), acts to cleave the N-terminal dipeptide, thus inactivating the hormones (to be discussed subsequently). K T N I Q H *Amino acids shown in gold are homologous with the structure of glucagon.

10 Synthesis and Secretion of GLP-1 and GIP
K-Cell (jejunum) ProGIP GIP [1-42] L-Cell (ileum) Proglucagon GLP-1 [7-37] GLP-1 [7-36NH2] Slide 10 This schematic compares the synthesis and secretion of GLP-1 and GIP. Both GLP-1 and GIP are released from the gut in response to nutrient intake—primarily glucose and fat. GLP-1 is synthesized from proglucagon in specialized endocrine L-cells located in the mucosa of the lower intestine. GIP is synthesized in K-cells located in the upper intestinal mucosa.

11 Mεταβολισμός GLP-1 και GIP
Active Hormones GLP-1 [7-36NH2] GIP [1-42] Capillary DPP-4 Inactive Metabolites GLP-1 [9-36NH2] GIP [3-42] Dipeptidyl peptidase-4 (DPP-4) Ubiquitous, specific protease Cleaves N-terminal dipeptide Inactivates > 50% of GLP-1 ~ 1 min > 50% of GIP in ~ 7 min Slide 11 This schematic describes the metabolism of GLP-1 and GIP. Following release of the peptides into the circulation, by the ubiquitous but specific serine protease, DPP-4, cleaves the N-terminal two amino acids from active GIP and GLP-1. This process is rapid and the plasma half-lives of GLP-1 and GIP are 1 and 7 minutes, respectively. The degradation products, GLP-1 [9-36] amide and GIP [3-42], do not stimulate insulin secretion.

12 Μεταβολισμός GLP-1 και GIP
L-Cell K-Cell Proglucagon ProGIP GIP [1-42] Capillary GLP-1 [7-37] Capillary GLP-1 [7-36NH2] GIP [1-42] ACTIVE GLP-1[7-36NH2] ACTIVE DPP-4 DPP-4 Dipeptidyl peptidase-4 (DPP-4) Ubiquitous, specific protease Cleaves N-terminal dipeptide Inactivates > 50% of GLP-1 in ~ 1 min > 50% of GIP in ~ 7 min GIP [3-42] INACTIVE GLP-1 [9-36NH2] INACTIVE FOR MONOGRAPH, not a slide This schematic compares the synthesis, secretion, and degradation of GLP-1 and GIP. Both GLP-1 and GIP are released from the gut in response to nutrient intake—primarily glucose and fat. GLP-1 is synthesized by alternative processing of the proglucagon molecule in L-cells located in the lower intestine. GIP is synthesized in K-cells located in the upper intestine. Both peptides are released into the circulation, where they are rapidly metabolized by the ubiquitous but specific serine protease, DPP-4, which cleaves the N-terminal two amino acids from peptides with an alanine or proline in the penultimate position. The products of metabolism, GLP-1 [9-36] amide and GIP [3-42], do not stimulate insulin secretion.

13 30-Minute Εκκριση Total and Intact GLP-1 and GIP in σε Υγιη Ατομα
Slide 13 This slide shows the 30 minute incremental area under the curve (AUC) for total and intact GLP-1 and GIP following a 520 kcal mixed breakfast meal in healthy volunteers. Total GLP-1 and GIP were measured with C-terminally directed antibodies. Intact, biologically active GLP-1 and GIP were measured with N-terminally directed antibodies. The intact peptides accounted for approximately 50% of the total immunoreactivities. The amount of GIP released was >3-fold greater than GLP-1 on a molar basis. Vilsbøll T, et al. J Clin Endocrinol Metab. 2003;88:

14 -Cell Τόπος Δράσης Ac Ac GLP-1 GIP Gs Gs -cell -cell Adipocyte
ATP ATP Ac Ac GLP-1 GIP cAMP cAMP Gs Gs PKA -cell Adipocyte Brain Stomach Small intestine -cell Adipocyte Brain Adrenal Pituitary Insulin Slide 14 This slide lists the primary tissues which express the GLP-1 and GIP receptors. In the -cell the binding of GLP-1 and GIP to their specific receptors activates the cAMP/PKA signaling pathway. However, other signaling pathways have recently been described in -cells that are activated following binding of the incretins. It is unclear what signaling mechanisms are activated by incretin binding in other tissues.

15 Glucose-Dependent Insulinotropic Effect of GLP-1 and GIP in Healthy Subjects
Test Infusion GL Test Infusion GL Slide 15 This slide illustrates the glucose-dependent insulinotropic effects of GLP-1 and GIP in healthy human subjects. Saline, GLP-1, or GIP was infused from –30 to 40 minutes (test infusion) and an IV glucose infusion (GL) was superimposed from 0 to 20 minutes. As shown in the left panel, plasma glucose rose promptly with IV administration and was higher during IV saline than during GIP or GLP-1 infusion. The insulin responses in this experiment are shown on the right. Neither GLP-1 nor GIP stimulated insulin release while plasma glucose was at the basal level. During the glucose infusion insulin secretion was significantly greater during the administration of GIP and GLP-1 than during saline. The enhanced insulin response with incretin administration may account for the improved glucose tolerance. Kreymann B, et al. Lancet. 1987;2:

16 Impaired Glucose Tolerance in GLP-1 Receptor Knockout Mice
* r -/- r -/- * * * * * * * * * +/+ -/ /+ -/ /+ -/- Slide 16 This slide depicts glucose and insulin levels during an oral glucose tolerance test in male mice with a targeted disruption of the GLP-1 receptor (GLP-1r -/-) and in wild type control mice (+/+). There was a significant increase in fasting glucose levels in the GLP-1 receptor knockout mice, as well as markedly impaired glucose tolerance compared to wild type mice (left). The GLP-1r -/- mice also had impaired insulin secretion, most notably in the first 30 minutes after the glucose load. **P < .01, *P < .05 Scrocchi LA, et al. Nat Med. 1996;2:

17 Impaired Glucose Tolerance in GIP Receptor Knockout Mice
*** * * ** Slide 17 This slide depicts glucose and insulin levels during an oral glucose tolerance test in male mice with a targeted disruption of the GIP receptor (GIPr -/-) and in wild type control mice (+/+). Fasting glucose levels were normal in the GIP receptor knockout mice. However, the mice had markedly impaired glucose tolerance and a greatly impaired early insulin response to oral glucose. Similar to the GLP-1r -/- mice, the early phase of postprandial insulin release was most notably abnormal in the GIP receptor knockouts ***P < .001, **P < .01, *P < .05. Miyawaki K, et al. Proc Natl Acad Sci U S A. 1999;96:

18 GLP-1 Decreases Glucagon and Glucose Levels in Patients with Type 1 Diabetes
* GLP-1 P < .001 Placebo GLP-1 or Placebo Slide 18 This slide illustrates the effect of GLP-1 to suppress plasma glucagon. Patients with type 1 diabetes were given IV GLP-1 or saline in a cross over study. In response to GLP-1 plasma glucagon decreased by more than 50%. The reduction of glucagon was accompanied by a significant decrease in plasma glucose levels in these patients with minimal -cell function. Creutzfeldt WO, et al. Diabetes Care. 1996;19:580-6.

19 GLP-1 Decreases Gastric Emptying of a Solid Meal in Healthy Subjects
Saline Slide 19 This slide illustrates one extra-pancreatic effect of GLP-1. Healthy volunteers received an infusion of synthetic GLP-1 or saline sufficient to reproduce levels measured during a meal. Gastric emptying, depicted as the percentage of a solid meal remaining in the stomach, was substantially slowed in the subjects receiving GLP-1. Näslund E, et al. Am J Physiol. 1999;277:R910-R916.

20 Effect of GLP-1 on -Cell Mass in Diabetic Rats
b-Cell Proliferation b-Cell Mass b-Cell Apoptosis P < .01 P < .001 P < .05 Slide 20 This slide illustrates findings from ultrastructural analyses of pancreases removed from Zucker diabetic fatty (ZDF) rats that received a 2-day continuous infusion of GLP-1 or saline. Administration of GLP-1 increased the percentage of -cells undergoing proliferation (left), and reduced the percentage of -cells undergoing apoptosis (programmed cell death; middle). The overall result of these alterations was an increase in -cell mass. Farilla L, et al. Endocrinology. 2002;143:

21 Comparison of Physiology of GLP-1 and GIP
Site of production L-cells in ileum and colon K-cells in duodenum and jejunum Response to stimuli Indirect/neuronal Direct Inhibits glucagon Yes No Slows gastric emptying Stimulation of -cell growth/mass Major target tissues -cell, -cell, stomach, nervous system -cell, adipose tissue Antagonist Exendin [9-39] GIP [7-30] Receptor KO mice Yes, with IGT Slide 21 This slide reviews and compares aspects of the physiology of GLP-1 and GIP.

22 Το Φαινόμενο Ινκρετίνης στον ΣΔ τύπου 2

23 Το φαινόμενο Ινκρετίνης στον ΣΔ τύπου 2
Control Type 2 DM 240 180 90 240 180 90 Plasma Glucose (mg/dL) Plasma Glucose (mg/dL) IV Oral 30 20 10 30 20 10 *P < .05 C-Peptide (nmol/L) C-Peptide (nmol/L) * Slide 22 This slide compares the incretin effect in nondiabetic control subjects (left) with T2DM patients. Glucose was given either orally or as a matched intravenous infusion (top figures). In healthy volunteers, the C-peptide response to oral glucose greatly exceeded the response to an isoglycemic intravenous infusion (bottom left). This augmentation of the insulin response during the OGT was nearly absent in patients with T2DM (bottom right). The incretin effect, calculated from the difference in the integrated C-peptide responses during oral and IV glucose, was 58% in nondiabetic subjects and only 8% in diabetic patients. Time (min) Time (min) Nauck M, et al. Diabetologia. 1986;29:46-52.

24 Εκκριση Ινκρετινών μετα απο γευμα σε ασθενεις με ΣΔ τυπου 2
GLP-1 GIP P = 0.095 P < 0.001 Slide 23 This slide compares the circulating levels of total GLP-1 (left panel) and GIP (right panel) following a mixed meal in subjects with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and T2DM. The release of GLP-1, as represented by the incremental 4-hour AUC, was significantly impaired in patients with T2DM relative to subjects with NGT or IGT. There was a modest reduction in GIP levels in patients with T2DM relative to subjects with NGT, but this was not statistically significant. NGT IGT T2DM Toft-Nielsen MB, et al. J Clin Endocrinol Metab. 2001;86:

25 Διαφορετική ινσουλινοτρόπος δραση των ινκρετινών στον ΣΔ τυπου 2
Hyperglycemic Clamp Saline or GIP or GLP-1 GLP-1 GIP Saline Slide 24 This slide depicts C-peptide levels in patients with T2DM during a hyperglycemic clamp with concurrent IV administration of GIP, GLP-1 or saline. The infusion of GLP-1 or GIP resulted in supraphysiologic plasma concentrations of the peptides. In these diabetic subjects, hyperglycemia alone or together with GIP led to very modest increases in C-peptide levels. In contrast, GLP-1 infusion greatly augmented the -cell response to glucose in patients with T2DM. Vilsböll T, et al. Diabetologia. 2002;45:

26 IV χορηγηση GLP-1 σε ασθενεις με ΣΔ τυπου 2
Glucose (mg/dL) C-Peptide (nmol/L) Glucagon (pmol/L) * GLP-1 Saline GLP-1 Infusion Slide 25 This slide illustrates the effect of GLP-1 infusion on fasting plasma glucose, C-peptide, and glucagon levels in patients with T2DM. Administration of GLP-1 decreased plasma glucose from > 200 mg/dl to < 100 mg/dl over 3-4 hours. Insulin secretion was increased, and glucagon secretion reduced by GLP-1. As the blood glucose approached normal levels the effect of GLP-1 on islet hormone release waned and insulin and glucagon returned to near basal levels. *P < .05 Nauck MA, et al. Diabetologia. 1993;36:741-4.

27 6 εβδομαδες συνεχους χορηγησης GLP-1 σε ασθενεις με ΣΔ τυπου 2
Patients assigned saline Patients assigned GLP-1 Meal Meal Slide 26 20 patients with T2DM were assigned to receive either GLP-1 or saline as a continuous subcutaneous infusion for 6 weeks. The patients had previous oral antidiabetic medication withdrawn for 3 weeks before the study. The group receiving saline (left) had fasting hyperglycemia and glucose intolerance that was unchanged before and at the 1 and 6 week follow up evaluations. Subjects receiving GLP-1 (right) had abnormalities in plasma glucose that was similar to the saline group at week 0. However, infusion of GLP-1 dramatically reduced both fasting and post meal glycemia at the 1 and 6 week follow up visits. The equivalent glucose profiles in the GLP-1 group at 1 and 6 weeks indicates that there was no diminution of the effect of treatment over time. Week 0 Week 1 Week 6 Zander M, et al. Lancet. 2002;359:

28 Effects of 4 Weeks’ Treatment with a DPP-4 Inhibitor in Patients with Type 2 Diabetes
Glucose GLP-1 meal Insulin Glucagon Slide 31 This slide illustrates the findings of a 4-week, placebo-controlled trial of the long-acting, orally effective, DPP-4 inhibitor, LAF237. Diabetic patients controlled with diet alone (baseline HbA1c ~7.2%) were randomized to receive placebo or LAF237 (100 mg) once daily. Depicted here are the plasma levels of glucose, insulin, active GLP-1, and glucagon measured during a standardized meal challenge performed on day 28 of treatment. Fasting and postprandial glucose levels were significantly decreased in patients receiving LAF237, as was the glucagon response to the mixed meal. Plasma levels of intact (N-terminally detected) GLP-1 were significantly increased. The insulin response to the meal was unchanged; however, the insulinogenic index was increased, suggesting stimulation of insulin secretion. Time (min) Time (min) Ahren B, et al. JCEM. 2004;(in press).

29 4 εβδομαδες θεραπεια με ινκρετινομιμητικα φαρμακα ( GLP-1 Receptor Agonist ) σε αθενεις με ΣΔ τυπου 2 Placebo Meal | P < .001 | P < .001 Drug (all arms) Slide 28 This slide depicts glucose excursions during a standardized meal challenge (right panel) and the change of HbA1c (left panel) reported in a 28-day, placebo-controlled clinical trial of the DPP-4–resistant GLP-1 receptor agonist, exendin-4, also known as AC2993 or exenatide. Placebo or exenatide (0.08 g/kg) was injected twice a day (BD = before breakfast and dinner; BS = before breakfast and at bedtime) or 3 times a day in patients with T2DM while they continued taking their previous oral antidiabetic medication. Because the effects of each regimen were similar, the meal challenge data from all exenatide treatment arms were pooled. Exenatide significantly reduced fasting and postprandial glucose levels. Baseline HbA1c averaged 9.3% and was reduced by 0.7 to 1.1% in this 4-week study. However, nausea was experienced by 31% of patients receiving exenatide, vomiting occurred in 15%, and severe nausea led to discontinuation of treatment in 3 of the 81 patients treated with exenatide. BD = before breakfast and dinner Fineman MS, et al. Diabetes Care. 2003;26:

30 Week 30 Meal Tolerance Test*
At 30 Weeks, PPG Remained Low among Patients Treated with GLP-1 Analogue Week 30 Meal Tolerance Test* Time (Min) 16 15 14 13 12 11 10 9 8 Postprandial Plasma Glucose (mmol/L) Injection Meal 7.5 Placebo (n=23) 5 µg exenatide (n=27) 10 µg exenatide (n=27) At 30 Weeks, PPG Remained Low among Patients Treated with GLP-1 Analogue The same study of exenatide in patients being treated with metformin and a sulfonylurea demonstrated that exenatide yields significant reductions in postprandial glucose (PPG).1 PPG concentrations were evaluated in a subset of patients who underwent a standardized meal tolerance test. At baseline, the geometric mean area under the curve (AUC) values for PPG were similar across all treatment arms. However, by Week 4, PPG AUC had decreased in both exenatide groups compared with placebo (P <0.001). As shown in the graph, this pattern continued through Week 30 (P <0.001). Reference Kendall DM, et al. Effects of exenatide (exendin-4) on glycemic control over 30 weeks in patients with type 2 diabetes treated with metformin and a sulfonylurea. Diabetes Care. 2005; 28: 1083–1091. GLP-1=glucagon-like peptide-1; PPG=postprandial glucose *Exendin-4 or placebo were administered at time zero; subjects in all treatment arms were maintained on metformin-sulfonylurea therapy. Adapted from Kendall DM, et al. Diabetes Care. 2005; 28: 1083–1091.

31 Μεταβολικές δράσεις GLP-1 σε συνεχη χορηγηση επι 6 εβδομαδες σε ασθενεις με ΣΔ τυπου 2
Slide 27 This slide depicts percent change from baseline to Week 6 of key metabolic parameters in T2DM patients receiving continuous GLP-1 through an insulin pump. Insulin sensitivity (as assessed during a hyperinsulinemic euglycemic clamp) and insulin secretion (as assessed by the ratio of the 8-hour AUCs for insulin and glucose [insulinogenic index]) were significantly increased. HbA1c, fasting glucose and fasting plasma glucagon were significantly reduced. The magnitude of the change in HbA1c ( = -1.3%) is notable considering the short duration of treatment. Gastric emptying and assessments of hunger were decreased. Zander M, et al. Lancet. 2002;359:

32 Effect of Bedtime Administration of a Long-acting GLP-1 Derivative in Patients with T2DM
Breakfast Breakfast Placebo Drug Placebo Drug Slide 29 This slide shows the effects of a single dose of a new long-acting derivative of GLP-1, originally designated as NN2211 and currently known as liraglutide. Liraglutide (10 g/kg) or placebo was given as a single subcutaneous injection at bedtime to 11 patients with T2DM in a double-blind crossover study. Liraglutide significantly decreased fasting and postprandial glucose levels and modestly increased the insulin secretion rate. The improvement of -cell function with NN2211 occurred despite the lower plasma glucose levels. Nausea was reported by 2 of the 11 patients after the injection of liragludide. Juhl CB, et al. Diabetes. 2002;51:424-9.

33 Glucose Tolerance, Insulin, and GLP-1 Levels in DPP-4 Deficient Mice
+/+ DPP-4 -/- *** * * ** Slide 30 This slide depicts glucose, GLP-1, and insulin levels during oral glucose tolerance tests performed in transgenic mice with a targeted disruption of the gene encoding for dipeptidyl peptidase IV (DPP-4, -/-) and wild type control animals (+/+). The active forms of the incretins was predicted to increase in these animals because of the absence of DPP-4 activity. The DPP-4 knockout mice had better glucose tolerance than wild-type control mice, increased plasma GLP-1, and enhanced insulin release. These mice have a normal phenotype and lifespan. ***P < .001, *P < .01, *P < .05 Marguet D, et al. Proc Natl Acad Sci U S A. 2000;97:

34 GLP-1 Analogues Enhance Glucagon Secretion in Hypoglycemic Conditions
Glucose Clamp Steps 300 (mmol/L): Recovery * * * 250 Exenatide† (n=11) 200 Placebo (n=11) Plasma Glucagon (ng/L) 150 100 GLP-1 Analogues Enhance Glucagon Secretion in Hypoglycemic Conditions The glucose-dependent nature of glucagon-like peptide-1 (GLP-1) activity is also evidenced by its effects on glucagon secretion in a hypoglycemic state. A study by Degn and colleagues assessed whether glucose-dependent glucagon secretion was preserved during hypoglycemia in the presence of exenatide, a GLP-1 analogue. Healthy fasted volunteers (n=12) were randomized in crossover study to receive either intravenous exenatide (0.066 pmol/kg/min) or placebo during a 270-minute stepwise hyperinsulinemic-hypoglycemic clamp (insulin infusion 0.8 mU/kg/min). Plasma glucose was then clamped sequentially at 5.0 (0–120 minutes), 4.0 (120–180 minutes), 3.2 (180–240 minutes), and 2.7 mmol/L (240–270 minutes). At 270 minutes, insulin infusion was terminated and plasma glucose increased to 3.2 mmol/L. The time to achieve plasma glucose >4.0 mmol/L thereafter was recorded. During euglycemic hyperinsulinemia, plasma glucagon was reduced by 50% in the exenatide arm (14.9 ± 7.3 ng/L) compared with the placebo arm (28.4 ± 14.0 ng/L) (90–120 minutes, P <0.05). Plasma glucagon increased throughout the hypoglycemic steps in both treatment groups, with significantly lower glucagon concentrations with exenatide treatment at 4.0 mmol/L plasma glucose (150–180 minutes: exenatide 26.9 ± 3.6 ng/L vs placebo 39.1 ± 5.2 ng/L, P <0.05). With the progression of hypoglycemia into the 2.7 mmol/L range, glucagon concentrations continued to increase, but in this case, significantly higher glucagon concentrations were observed in the exenatide treatment group (182.0 ± 29.0 ng/L) than in the placebo group (142.1 ± 22.6 ng/L) during the 240- to 270-minute glycemic interval (P <0.05). There was no difference between treatment arms during the recovery interval (270–360 minutes). Reference Degn KB, et al. Effect of intravenous infusion of exenatide (synthetic exendin-4) on glucose-dependent insulin secretion and counterregulation during hypoglycemia. Diabetes. 2004; 53: 50 – Time (Min) GLP-1=glucagon-like peptide-1 *P <0.05 †Exenatide infused at .066 pmol/kg/min for 270 minutes. Adapted from Degn KB, et al. Diabetes. 2004; 54: 2397–2403.

35 Συνοπτικά : Φυσιολογία των Ινκρετινών
Φαινόμενο Ινκρετίνης: Εκκριση ινσουλινης μεγαλύτερη μετα απο του στόματος χορήγηση γλυκόζης απο οτι με ενδοφλέβιο χορήγηση Οι ινκρετίνες : GLP-1 and GIP Αλλες δράσεις του GLP-1 : a) μειώνει την έκκριση γλυκαγόνης b) ελαττώνει την κένωση στομάχου c) αίσθημα πληρότητας. Καταβολίζονται γρήγορα απο το ένζυμο DPP-4 Το φαινόμενο ινκρετίνης δεν ειναι φυσιολογικό στον ΣΔ τύπου 2 Slide 32 Read as is.

36 Συνοπτικά : Θεραπείες βασιζόμενες στις Ινκρετίνες
GLP-1 πρέπει να χορηγείται με συνεχή χορήγηση για να ειναι αποτελεσματικο. GLP-1 receptor agonists που αντιστέκονται στην δράση του DPP-4 βελτιώνουν τον γλυκαιμικό έλεγχο στον ΣΔ τυπου 2 Απο του στόματος χορήγηση αναστολέων DPP-4 επιτυγχάνουν μείωση της υπεργλυκαιμίας. Slide 33 Read as is.

37 DPP-4 Αναστολείς

38 Inhibition of DPP-4 Increases Active GLP-1
Meal Intestinal GLP-1 release GLP-1 t½=1–2 min Active GLP-1 DPP-4 Inhibition of DPP-4 Increases Active GLP-1 Released by intestinal L-cells in response to ingested food (upper left), glucagon-like peptide-1 (GLP-1) is rapidly and extensively inactivated (lower right).1 The kinetics of the inactivation process were explored in eight healthy subjects and eight type 2 diabetes mellitus (T2DM) patients, all of whom were given the active amide GLP-1(7–36) (administered subcutaneously or intravenously).2 In all instances, the active amide was rapidly attacked at its N-terminus by dipeptidyl peptidase-4 (DPP-4), leaving the inactive metabolite GLP-1(9–36) and giving the active amide a half-life of only 1–2 minutes.2 Early on in the development of DPP-4 inhibitor therapy, it was hypothesized that inhibition of DPP-4 may enable endogenous GLP-1 to avoid inactivation, augment the deficient incretin response seen in T2DM, and improve metabolic control across the multiple defects associated with the disorder. Such hopes were the impetus for an exploratory trial in which 12 healthy subjects fasted overnight and then ate a standardized breakfast 30 minutes after receiving single oral doses of placebo or the active drug NVP-DPP728.3 The active drug increased the subjects’ plasma levels of prandial active GLP-1, with concomitant reduction in prandial glucose exposure. These findings, reported in 2000, were the first to provide direct evidence that inhibition of DPP-4 could be a viable pharmacologic approach for potentiating the activity of endogenous GLP-1 in humans.3 References Kieffer TJ, et al. Degradation of glucose-dependent insulinotropic polypeptide and truncated glucagon-like peptide 1 in vitro and in vivo by dipeptidyl peptidase IV. Endocrinology. 1995; 136: 3585–3596. Deacon CF, et al. Both subcutaneously and intravenously administered glucagon-like peptide 1 are rapidly degraded from the NH2-terminus in type II diabetic patients and in healthy subjects. Diabetes. 1995; 44: 1126–1131. Rothenberg P, et al. Treatment with a DPP-IV inhibitor, NVP-DPP728, increases prandial intact GLP-1 levels and reduces glucose exposure in humans. Diabetes. 2000; 49(suppl 1): A39. Abstract 160-OR. GLP-1 inactive (>80% of pool) DPP-4=dipeptidyl peptidase-4; GLP-1=glucagon-like peptide-1 Adapted from Rothenberg P, et al. Diabetes. 2000; 49(suppl 1): A39. Abstract 160-OR. Adapted from Deacon CF, et al. Diabetes. 1995; 44: DPP-4 inhibitor

39 Incretin response diminished Incretin activity prolonged
Blocking DPP-4 Can Improve Incretin Activity and Correct the Insulin:Glucagon Ratio in T2DM  Insulin  Glucagon Hyperglycemia Incretin response diminished Further impaired islet function T2DM  Insulin  Glucagon Improved glycemic control Incretin activity prolonged Improved islet function DPP-4 inhibitor Blocking DPP-4 Can Improve Incretin Activity and Correct the Insulin:Glucagon Ratio in T2DM Patients with type 2 diabetes mellitus (T2DM) have an imbalance in their insulin:glucagon ratio, which is largely responsible for hyperglycemia.1 By inhibiting dipeptidyl peptidase-4 (DPP-4) and prolonging incretin activity, this imbalance can be corrected and glycemic control improved, as shown by the schematic on this slide.2 Pancreatic islet dysfunction is considered a prerequisite for T2DM. The activity of both β-cells and -cells is impaired such that insulin secretion is decreased and glucagon secretion is increased. In addition, patients with diabetes have reduced concentrations of circulating incretins. This impairment exacerbates the defects in insulin and glucagon secretion because incretins act to stimulate glucose-sensitive insulin response and suppress glucagon release.1,2 By inhibiting DPP-4, incretin activity can be prolonged, leading to increased levels of active incretins. As a result, glucose-sensitive insulin and glucagon responses are corrected, and glycemic control is improved.2 References Unger RH. Alpha- and beta-cell interrelationships in health and disease. Metabolism. 1974; 23: 581–593. Ahrén B. Inhibition of dipeptidyl peptidase-4 (DPP-4)—a novel approach to treat type 2 diabetes. Curr Enzyme Inhib. 2005; 1: 65–73. DPP-4=dipeptidyl peptidase-4; T2DM=type 2 diabetes mellitus Adapted from Unger RH. Metabolism. 1974; 23: 581–593. Ahrén B. Curr Enzyme Inhib. 2005; 1: 65–73.

40 Vildagliptin – a potent and selective DPP-4 inhibitor
Highly selective DPP-4 inhibitor Has a high affinity for the human enzyme Reversible inhibition Vildagliptin – a potent and selective DPP-4 inhibitor Vildagliptin, previously known as LAF237, is a potent and reversible inhibitor of human dipeptidyl peptidase-4 (DPP-4) with an IC50 of approximately 3 nM. Vildagliptin is highly selective for DPP-4 and displays slow-tight-binding kinetics with very slow dissociation rates: the vildagliptin/DPP-4 complex dissociates with a half-life of about 55 minutes.1 Reference Burkey BF, et al. Vildagliptin displays slow-tight binding to dipeptidyl peptidase (DPP)-4, but not DPP-8 or DPP-9. Poster 0788 presented at EASD 2006. X-ray crystallographic structure of vildagliptin (green) bound to the active site (yellow) of human DPP-4 DPP-4=dipeptidyl peptidase-4

41 Vildagliptin Provides Potent and Dose-dependent Inhibition of DPP-4 in Patients with T2DM
Placebo (n=16) Vilda 10 mg (n=16) Vilda 25 mg (n=16) Vilda 50 mg (n=16) Vilda 100 mg (n=15) Vilda 200 mg (n=16) Vilda 400 mg (n=16) Vildagliptin Provides Potent and Dose-dependent Inhibition of DPP-4 in Patients with T2DM Dose-response relationships to single oral doses (10–400 mg) of vildagliptin were assessed in this randomized, open-label, placebo-controlled seven-period crossover study in 16 patients with type 2 diabetes mellitus (T2DM), using the oral glucose tolerance test.1 Single oral doses of placebo or vildagliptin were administered after an overnight fast, followed 30 minutes later by administration of a 75 g oral glucose load. Plasma dipeptidyl peptidase-4 (DPP-4) activity was measured at intervals during the ensuing 24 hours. Plasma DPP-4 activity was unchanged after placebo administration but was rapidly and markedly inhibited after each dose of vildagliptin. Both onset and duration of DPP-4 inhibition were dose-dependent but >90% inhibition occurred within 45 minutes and was maintained for ≥ 4 hours after each dose. Reference 1. He YL, et al. Pharmacodynamics of vildagliptin in patients with type 2 diabetes. In press. DPP-4=dipeptidyl peptidase-4; T2DM=type 2 diabetes mellitus; vilda=vildagliptin He YL, et al. In press.

42 OGTT 30 Min after Single Oral Dose of Vildagliptin (100 mg)
Vildagliptin Enhances Islet Cell Function by Increasing Insulin and Decreasing Glucagon Secretion OGTT 30 Min after Single Oral Dose of Vildagliptin (100 mg) 75 g Glucose 120 Placebo (n=16) Vildagliptin 100 mg (n=15) 100 Insulin (pmol/L) 80 Dose 60 40 20 −90 −60 −30 30 60 90 120 150 180 210 240 270 300 22.5 Glucose (mmol/L) 17.5 12.5 Vildagliptin Enhances Islet Cell Function by Increasing Insulin and Decreasing Glucagon Secretion Dose-response relationships to single oral doses of vildagliptin were assessed in this randomized, open-label, placebo-controlled crossover study in 16 patients with type 2 diabetes mellitus, using the oral glucose tolerance test.1 Single oral doses of placebo or vildagliptin were administered after an overnight fast, followed 30 minutes later by administration of a 75 g oral glucose load. Plasma levels of insulin (top), glucose (middle), and glucagon (bottom) were assessed.1 A single dose of vildagliptin 100 mg significantly increased the insulin area under the curve (AUC) and significantly decreased the AUCs for glucose and glucagon. This study demonstrates that vildagliptin enhances islet cell function by increasing insulin secretion and decreasing glucagon secretion, thus reducing glucose levels. Reference He YL, et al. Pharmacodynamics of vildagliptin in patients with type 2 diabetes. In press. 7.5 −90 −60 −30 30 60 90 120 150 180 210 240 270 300 140 Glucagon (ng/L) 120 100 80 60 −90 −60 −30 30 60 90 120 150 180 210 240 270 300 Time OGTT=oral glucose tolerance test *P <0.01. He YL, et al. In press.

43 Vildagliptin Enhances GLP-1 Levels in Patients with T2DM
Meal Placebo (n=16) 16.0 * Vildagliptin 100 mg (n=16) * * 12.0 * * * * * Active GLP-1 (pmol/L) 8.0 * * * * Vildagliptin Enhances GLP-1 Levels in Patients with T2DM In this randomized, double-blind study, patients with type 2 diabetes mellitus (n=16) received, on different days, a single dose of vildagliptin 100 mg or placebo, followed 30 minutes later by a standard evening meal containing radio-labeled glucose (75 g), allowing a meal tolerance test (MTT) to be carried out.1 Plasma samples during the MTT were taken and glucagon-like peptide-1 (GLP-1) levels estimated by enzyme-linked immunosorbent radioimmune assay using an N-terminal specific antibody. Following dosing with vildagliptin 100 mg, there was a prompt and virtually complete suppression of plasma dipeptidyl peptidase-4 (DPP-4) activity.1 DPP-4 inhibition was associated with a significant post-meal increase in GLP-1 (and glucose-dependent insulinotropic peptide [GIP]; data not shown), which persisted for 14 hours.1 This study demonstrated that treatment with vildagliptin leads to increased GLP-1 levels that persist well beyond the post-meal period. Reference 1. Balas B, et al. The dipeptidyl peptidase IV inhibitor vildagliptin suppresses endogenous glucose production and enhances islet function after single-dose administration in type 2 diabetic patients. J Clin Endocrinol Metab. 2007; Epub ahead of print. * 4.0 0.0 17:00 20:00 23:00 02:00 05:00 08:00 Time GLP-1=glucagon-like peptide-1 *P <0.05 Balas B, et al. J Clin Endocrinol Metab. 2007; Epub ahead of print.

44 Vildagliptin Suppresses Glucagon Secretion
Meal 20 Placebo (n=16) 10 Vildagliptin 100 mg (n=16) −10 Delta Glucagon (ng/L) −20 * −30 * Vildagliptin Suppresses Glucagon Secretion In this randomized, double-blind study, patients with type 2 diabetes mellitus (n=16) received, on different days, a single dose of vildagliptin 100 mg or placebo, followed 30 minutes later by a standard evening meal containing radio-labeled glucose (75 g), allowing a meal tolerance test (MTT) to be carried out.1 Plasma samples during the MTT were taken and glucagon levels estimated by radioimmune assay. Administration of dipeptidyl peptidase-4 (DPP-4) was associated with a 5-fold (P <0.02) greater suppression of glucagon than placebo during MTT; these effects persisted through the overnight period.1 These results show that vildagliptin results in DPP-4 suppression that persists throughout the overnight period. Reference 1. Balas B, et al. The dipeptidyl peptidase IV inhibitor vildagliptin suppresses endogenous glucose production and enhances islet function after single-dose administration in type 2 diabetic patients. J Clin Endocrinol Metab. 2007; Epub ahead of print. −40 * * −50 * * * * * −60 17:00 20:00 23:00 02:00 05:00 08:00 Time *P <0.05 vs placebo Balas B, et al. J Clin Endocrinol Metab. 2007; Epub ahead of print.

45 Vildagliptin Suppresses Endogenous Glucose Production
Time Meal 17:00 20:00 23:00 02:00 05:00 08:00 * −0.3 −0.6 Delta EGP (mg/kg/min) −0.9 Vildagliptin Suppresses Endogenous Glucose Production In this randomized, double-blind study, patients with type 2 diabetes mellitus (n=16) received, on different days, a single dose of vildagliptin 100 mg or placebo, followed 30 minutes later by a standard evening meal containing radio-labeled glucose (75 g), allowing a meal tolerance test (MTT) to be carried out.1 Plasma samples during the MTT were taken and endogenous glucose production (EGP) was assessed. This primarily reflects activity in the liver, with a small contribution from the kidney. In both the vildagliptin and placebo groups, there was a prompt suppression of EGP following the meal. However, within 60 minutes of ingestion of the meal, suppression of EGP was greater with vildagliptin, as it was at all subsequent time points. At 0–240, 0–480, and 0–840 minutes after dosing, the suppression of EGP was 25%, 34%, and 59% greater (all P ≤0.01) with vildagliptin compared with placebo. This study demonstrates that vildagliptin suppresses EGP. The decrease in overnight EGP after vildagliptin correlated with the decrease in plasma glucagon (r= −0.49, P <0.05) and fasting plasma glucose concentration (r=0.55, P <0.03). Reference Balas, B et al. The dipeptidyl peptidase IV inhibitor vildagliptin suppresses endogenous glucose production and enhances islet function after single-dose administration in type 2 diabetic patients. J Clin Endocrinol Metab. 2007; Epub ahead of print. Placebo (n=16) −1.2 Vildagliptin 100 mg (n=16) −1.5 *P <0.05 vs placebo Balas B, et al. J Clin Endocrinol Metab. 2007; Epub ahead of print.

46 Vildagliptin Increases Levels of Active Incretins in Patients with T2DM
Intact GIP (pmol/L) Intact GLP-1 (pmol/L) 250 35 30 200 25 150 20 // // 15 100 // 10 // // 50 // 5 Vildagliptin Increases Levels of Active Incretins in Patients with T2DM Dipeptidyl peptidase-4 inhibitors target both glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). Mari and colleagues thus studied the effect of vildagliptin on the levels of active incretins in treatment-naïve patients with type 2 diabetes mellitus.1 Patients were treated with 100 mg twice-daily oral vildagliptin (n=9) or placebo (n=11) for 28 days. Insulin secretion rate and plasma levels of glucose, insulin, and intact GIP and GLP-1 were evaluated before and after 28 days of treatment. Plasma levels of intact GLP-1 and GIP more than doubled compared with baseline during treatment with vildagliptin. In contrast, with placebo, levels of intact GLP-1 remained stable, while levels of GIP increased only marginally (data not shown). Notably, the insulin secretory rate was greater among patients treated with vildagliptin vs placebo patients (data not shown). These data demonstrate that treatment with vildagliptin increases levels of active incretins in patients with T2DM. Reference Mari A, et al. Vildagliptin, a dipeptidyl peptidase-IV inhibitor, improves model-assessed β-cell function in patients with type 2 diabetes. J Clin Endocrinol Metab. 2005; 90: 4888–4894. –2 2 4 6 8 10 12 14 16 –2 2 4 6 8 10 12 14 Time (h) Time (h) Vildagliptin Day 1 Vildagliptin Day 28 GIP=glucose-dependent insulinotropic peptide; GLP-1=glucagon-like peptide-1; T2DM=type 2 diabetes mellitus Adapted from Mari A, et al. J Clin Endocrinol Metab. 2005; 90: 4888–4894.

47 Vildagliptin Improves First-Phase Insulin Response in Drug-Naïve T2DM Patients
40 60 80 100 120 140 160 180 −6 −4 −2 2 4 6 8 10 12 Time (Min) Insulin (pmol/L) Vildagliptin 100 mg daily Week 0 Vildagliptin 100 mg daily Week 12 * >3-fold increase in AIRg (P <0.001 vs Week 0, P <0.001 vs placebo) Vildagliptin Improves First-Phase Insulin Response in Drug-Naïve T2DM Patients The development of type 2 diabetes mellitus (T2DM) is characterized by loss of the acute insulin response to glucose (AIRg) and impaired glucose sensitivity. In this study of parameters of islet function, drug-naïve patients with T2DM (n=12) received vildagliptin 100 mg daily for 12 weeks.1 Data show plasma insulin levels during the initial 10 minutes post-glucose, during frequently sampled intravenous glucose tolerance tests. The tests were performed before (Week 0) and after (Week 12) administration of vildagliptin. Relative to baseline (Week 0), after 12-week treatment with vildagliptin, plasma insulin levels were significantly increased at 2, 6, and 8 minutes post-glucose. There was a significant increase in AIRg of >3-fold relative to baseline, indicating a restoration effect for vildagliptin.1 Twelve-week treatment with vildagliptin 100 mg daily was shown to improve the first-phase insulin response in this study.1 Reference 1. D’Alessio DA, et al. Restoration of an acute insulin response to glucose (AIRg) in drug-naïve patients with type 2 diabetes (T2DM) by 3-month treatment with vildagliptin. Poster 454-P presented at ADA 2006. AIRg=acute insulin response to glucose; T2DM=type 2 diabetes mellitus *P <0.05 D’Alessio DA, et al. Poster 454-P presented at ADA 2006.

48 Vildagliptin: Enhances Insulin Sensitivity
Duration: 6 weeks Vildagliptin vs placebo Hyperinsulinemic Euglycemic Clamp 7.0 * 6.1 Vildagliptin 100 mg daily (n=8) 6.0 5.4 Placebo (n=8) 5.0 Glucose Rd (mg/kg/min) 4.0 3.0 Vildagliptin: Enhances Insulin Sensitivity The development of type 2 diabetes mellitus (T2DM) is characterized by impaired glucose sensitivity. In this randomized, placebo-controlled, two-period crossover study, the effects of vildagliptin on insulin action during stepped hyperinsulinemic clamps was investigated.1 Patients with T2DM (n=16) received vildagliptin 100 mg daily or placebo for 42 days in each of two periods. On Day 41, standard breakfast meal tests were conducted 30 minutes after the morning dose of study medication. On Day 42, study medication was not taken. Glucose kinetics were measured and indirect calorimetry was performed in the high-dose (80 mU/m2/min) euglycemic clamp. Rate of glucose disappearance is a parameter to measure insulin sensitivity. These results show that vildagliptin increases the rate of glucose disappearance, which relates to an increase in insulin sensitivity in patients with T2DM. Reference Azuma K, et al. Inhibition of DPP-4 evokes pancreatic and extra-pancreatic mechanisms that improve glucose homeostasis in type 2 diabetes mellitus. Diabetes (submitted). 2.0 1.0 0.0 Rd=rate of disappearance *P <0.05 Azuma K, et al. Diabetes (submitted).

49 Vildagliptin Reduces Postprandial Total Serum Triglycerides after 4 Weeks of Treatment
Vildagliptin 100 mg daily* Placebo** Week 0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 −1 1 2 3 4 5 6 7 8 Time (h) Total Serum TG (mmol/L) Week 0 Week 4 4.0 Week 4 3.5 3.0 Total Serum TG (mmol/L) 2.5 2.0 Vildagliptin Reduces Postprandial Total Serum Triglycerides after 4 Weeks of Treatment This randomized, double-blind study assessed the effects of vildagliptin on postprandial lipid and lipoprotein metabolism in drug-naïve patients with type 2 diabetes mellitus.1 Patients received vildagliptin (100 mg daily; n=15) or placebo (n=16) for 4 weeks. Before and after the treatment period, total serum triglycerides were determined for 8 hours following a fat-rich mixed meal.1 Relative to placebo, 4 weeks of vildagliptin treatment decreased the area under the curve0-8h for total triglyceride by 22 ± 11% (P=0.037).1,2 Vildagliptin treatment for 4 weeks reduces postprandial plasma triglycerides after a fat-rich meal. References Matikainen N, et al. Vildagliptin therapy reduces postprandial intestinal triglyceride-rich lipoprotein particles in patients with type 2 diabetes. Diabetologia. 2006; 49: Data on file, Novartis Pharmaceuticals. Study LAF2217, 2 December 2005, p.36. 1.5 1.0 −1 1 2 3 4 5 6 7 8 Time (h) TG=triglycerides ITT population (intention-to-treat). *Adapted from Matikainen N, et al. Diabetologia. 2006; 49: 2049–2057. **Study LAF2217. Data on file, Novartis Pharmaceuticals, 2 December 2005, p.36.

50 Vildagliptin Reduces Chylomicron Tryglycerides after 4 Weeks of Treatment
Vildagliptin 100 mg daily 0.8 Week 0 Week 4 0.6 0.4 Chylomicron TG (mmol/L) Vildagliptin Reduces Chylomicron Triglycerides after 4 Weeks of Treatment This randomized, double-blind study assessed the effects of vildagliptin on postprandial lipid and lipoprotein metabolism in drug-naïve patients with type 2 diabetes mellitus.1 Patients received vildagliptin (100 mg daily; n=15) or placebo (n=16) for 4 weeks. Before and after the treatment period, chylomicron triglycerides were determined for 8 hours following a fat-rich mixed meal. Relative to placebo, 4 weeks of vildagliptin treatment decreased the area under the curve0-8h for chylomicron triglyceride by 65 ± 19% (P=0.001).1 Vildagliptin treatment for 4 weeks reduces postprandial chylomicron triglyceride after a fat-rich meal.1 Reference 1. Matikainen N, et al. Vildagliptin therapy reduces postprandial intestinal triglyceride-rich lipoprotein particles in patients with type 2 diabetes. Diabetologia. 2006; 49: 0.2 0.0 -1 1 2 3 4 5 6 7 8 Time (h) TG=triglycerides Matikainen N, et al. Diabetologia. 2006; 49: 2049–2057.

51 Vildagliptin: No Effect on Gastric Emptying
143 145 150 125 100 T1/2 (Min) for Gastric Emptying 75 50 Vildagliptin: No Effect on Gastric Emptying In this study, gastric emptying was measured in 14 patients with type 2 diabetes mellitus treated with either vildagliptin 100 mg daily or placebo for 10 days using a double-blind, placebo-controlled, randomized, crossover design. The aim was to determine whether alterations in meal absorption and gastric emptying contribute to the mechanism by which dipeptidyl peptidase-4 inhibitors lower postprandial glucose concentrations.1 Gastric emptying was measured on the 9th day of each treatment period. Following an 8-hour fast, subjects received a standardized meal. Anterior and posterior gamma camera images were obtained immediately after meal ingestion and over the next 4 hours. Gastric emptying did not differ between treatments: T1/2 (time to empty 50% of stomach contents) was and minutes (not significant) for placebo- and vildagliptin-treated patients, respectively.1 Vildagliptin has no apparent effect on gastric emptying. Reference 1. Vella A, et al. Effects of dipeptidyl peptidase 4 inhibition on gastrointestinal function, meal appearance and glucose metabolism in type 2 diabetes. Diabetes. 2007: Epub ahead of print. 25 Placebo Vildagliptin 100 mg daily T1/2=time to empty 50% of stomach contents. Difference not statistically significant Vella A, et al. Diabetes. 2007: Epub ahead of print.

52 Patients on Stable Metformin Therapy nmolC-peptide · mmolglucose-1 ·
Vildagliptin Enhances -cell Function and Insulin Sensitivity over 52 Weeks Patients on Stable Metformin Therapy Insulin Secretion Insulin Sensitivity Adaptation Index 0.050 0.040 0.045 0.025 0.030 0.035 300 250 275 200 225 14 10 12 6 8 * * * * † * nmolC-peptide · mmolglucose-1 · mL-1 · m-2 pmol/L 30 min/(mmol/L) mL · min-1 · m -2 Vildagliptin Enhances -cell Function and Insulin Sensitivity over 52 Weeks This study examined the effects of dipeptidyl peptidase-4 (DPP-4) inhibition on meal-related β-cell function and insulin sensitivity over 52 weeks in patients with type 2 diabetes mellitus (T2DM). In a 12-week core study, placebo (n=51) or vildagliptin (n=56; 50 mg daily) was added to metformin treatment (1.5–3.0 mg/day); a 40-week extension followed in 71 patients. Meal tests were performed at 0, 12, 24, and 52 weeks. These included the evaluation of glucose, insulin, and C-peptide.1 Insulin secretion was defined as post-meal suprabasal area under the 0- to 30-min C-peptide curve divided by the 30-min increase in glucose. Insulin secretion and insulin sensitivity were significantly increased in the vildagliptin group after 52 weeks. With placebo, insulin secretion decreased while insulin sensitivity was not significantly altered. The between-treatment differences at 52 weeks were ± 0.03 pmol/L 30 min/mmol/L (P=0.018) for insulin secretion and 27 ± 4 mL min-1 m-2 (P=0.036) for insulin sensitivity. Insulin secretion related to insulin sensitivity (adaptation index) was significantly increased in the vildagliptin group but decreased in the placebo group after 52 weeks (between-treatment difference +3.2 ± 1.0, P=0.040). This study presents evidence that vildagliptin added to metformin provides sustained improvement of β-cell function and insulin sensitivity over 52 weeks.1 Reference 1. Ahrén B, et al. Improved meal-related beta-cell function and insulin sensitivity by the dipeptidyl peptidase-IV inhibitor vildagliptin in metformin-treated patients with type 2 diabetes over 1 year. Diabetes Care. 2005: 28: Time (Week) Time (Week) Time (Week) Vildagliptin 100 mg daily / metformin Placebo / metformin *P <0.05 vs placebo; †P <0.01 vs placebo. Adapted from Ahrén B, et al. Diabetes Care. 2005; 28: 1936–1940.

53 Vildagliptin: Improves β-cell Mass (Neonatal Rat Pancreatic Growth Model)
Insulin Vildagliptin 60 mg/kg 21 days Vehicle Replication Apoptosis -cell mass Vehicle Vilda P <0.05 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 120 P <0.001 2.5 100 2.0 80 Vildagliptin: Improves β-cell Mass (Neonatal Rat Pancreatic Growth Model) In type 2 diabetes mellitus (T2DM) there is a progressive impairment of pancreatic β-cell function and loss of β-cell mass, largely due to increased apoptosis. Therefore, a desirable attribute for an antidiabetic agent is an ability to improve β-cell mass. In this study, 48-hour-old rats were assigned to receive vehicle or vildagliptin (60 mg/kg, po) from Day 2. After 7 or 20 days, animals were injected with 5-bromo-2-deoxyuridine (BruD) and sacrificed, and then pancreatic tissue was harvested. Pancreatic insulin was visualized in tissue sections by immunoperoxidase staining. β-cell replication and apoptosis were visualized by BrdU and ApopTag® staining, respectively. Using morphometric analysis, β-cell mass was estimated by dividing the insulin-positive area by the total pancreatic area to derive β-cell area. On Day 7, β-cell replication was increased >8-fold (P <0.001) and apoptosis was decreased by 65% (P <0.05) in the vildagliptin group compared with the vehicle group. There was a trend towards increased β-cell mass. On Day 21, a 75% increase in β-cell area and mass was evident and this was statistically significant (P <0.05). Vildagliptin improves β-cell mass by stimulating replication and inhibiting apoptosis in this rodent model of β-cell turnover. However, the data should be interpreted with caution due to the physiological differences of β-cell turnover in rodents vs humans. Reference 1. Duttaroy A, et al. The DPP-4 inhibitor vildagliptin increases pancreatic beta cell neogenesis and decreases apoptosis. Poster 572 presented at ADA 2005. BrdU-Positive Cells (%) ApopTag-Positive Cells (%) 1.5 P <0.05 -cell Mass (mg) 60 1.0 40 20 0.5 0.0 Vehicle Vilda Vehicle Vilda Day 7 Day 21 Vilda=vildagliptin Duttaroy A, et al. Diabetes. 2005; 54 (suppl 1): A141. Abstract 572-P and poster presented at ADA.

54 ΣΥΜΠΕΡΑΣΜΑ Vildagliptin αναστέλλει DPP-4, με αποτέλεσμα:
επιπέδων GLP-1 και GIP νηστείας και μεταγευματικά Βελτιώνει την λειτουργία των κυττάρωντων νησιδίων του παγκρέατος: ευαισθησία γλυκοζοεξαρτωμενης έκκρισης γλυκαγόνης ευαισθησία γλυκοζοεξαρτωμενης έκκρισης ινσουλίνης πρώτη φάση έκκρισης ινσουλίνης δυνατοτητα των παγκρεατικών κυτταρων για έκκριση Μεταγευματικά τριγλυκερίδια Αντίσταση στην δράση της ινσουλίνης Δεν επηρεάζει την κένωση στομάχου DPP-4=dipeptidyl peptidase-4; GIP=glucose-dependent insulinotropic peptide; GLP-1=glucagon-like peptide-1

55 ΕΥΧΑΡΙΣΤΩ GLP-1 t½=1–2 min Meal Intestinal GLP-1 release Active GLP-1
DPP-4 Inhibition of DPP-4 Increases Active GLP-1 Released by intestinal L-cells in response to ingested food (upper left), glucagon-like peptide-1 (GLP-1) is rapidly and extensively inactivated (lower right).1 The kinetics of the inactivation process were explored in eight healthy subjects and eight type 2 diabetes mellitus (T2DM) patients, all of whom were given the active amide GLP-1(7–36) (administered subcutaneously or intravenously).2 In all instances, the active amide was rapidly attacked at its N-terminus by dipeptidyl peptidase-4 (DPP-4), leaving the inactive metabolite GLP-1(9–36) and giving the active amide a half-life of only 1–2 minutes.2 Early on in the development of DPP-4 inhibitor therapy, it was hypothesized that inhibition of DPP-4 may enable endogenous GLP-1 to avoid inactivation, augment the deficient incretin response seen in T2DM, and improve metabolic control across the multiple defects associated with the disorder. Such hopes were the impetus for an exploratory trial in which 12 healthy subjects fasted overnight and then ate a standardized breakfast 30 minutes after receiving single oral doses of placebo or the active drug NVP-DPP728.3 The active drug increased the subjects’ plasma levels of prandial active GLP-1, with concomitant reduction in prandial glucose exposure. These findings, reported in 2000, were the first to provide direct evidence that inhibition of DPP-4 could be a viable pharmacologic approach for potentiating the activity of endogenous GLP-1 in humans.3 References Kieffer TJ, et al. Degradation of glucose-dependent insulinotropic polypeptide and truncated glucagon-like peptide 1 in vitro and in vivo by dipeptidyl peptidase IV. Endocrinology. 1995; 136: 3585–3596. Deacon CF, et al. Both subcutaneously and intravenously administered glucagon-like peptide 1 are rapidly degraded from the NH2-terminus in type II diabetic patients and in healthy subjects. Diabetes. 1995; 44: 1126–1131. Rothenberg P, et al. Treatment with a DPP-IV inhibitor, NVP-DPP728, increases prandial intact GLP-1 levels and reduces glucose exposure in humans. Diabetes. 2000; 49(suppl 1): A39. Abstract 160-OR. GLP-1 inactive (>80% of pool)