Effects of exenatide and metformin in combination on some adipocytokine levels: a comparison with metformin monotherapy.

The aim of this study was to evaluate the effects of exenatide on levels of serum adipocytokines and on ß-cell function. The study was conducted between 2008 and 2012. After a run-in period with metformin, 174 patients with type-2 diabetes were randomly distributed to either a group receiving exenatide at 10 µg twice daily, or a group receiving the placebo, for 12 months. We evaluated body mass index (BMI), blood pressure, glycemic control, lipid profile, fasting plasma insulin (FPI), HOMA-IR, HOMA-ß, fasting plasma proinsulin (FPPr), proinsulin : fasting plasma insulin ratio (Pr/FPI ratio), C-peptide, glucagon, retinol binding protein-4 (RBP-4), visfatin, omentin-1, and microalbuminuria. We used ELISA methods to assess the various parameters. Patients also underwent a combined euglycemic-hyperinsulinemic and hyperglycemic clamp, with subsequent arginine stimulation. After 12 months, a combination of exenatide and metformin produced a better decrease in body mass, BMI, glycemic control, FPI, FPPr, FPPr/FPI ratio, HOMA-IR, and glucagon level. Treatment with exenatide + metformin was superior to the placebo + metformin in increasing HOMA-ß, C-peptide, and ß-cell function. Significant negative correlations were found between M value, an index of insulin sensitivity, and measured adipocytokines. In conclusion, the combination of exenatide + metformin plays a role in improving some adipocytokine levels, and is better than metformin alone. The significant negative correlation between M value and measured adipocytokines is another confirmation of the positive effects linked to the improvement in insulin sensitivity.

Variation in inflammatory markers and glycemic parameters after 12 months of exenatide plus metformin treatment compared with metformin alone: a randomized placebo-controlled trial.

STUDY OBJECTIVE: To evaluate the effects of exenatide on some inflammatory markers and to quantify the effect of exenatide on ß-cell function. DESIGN: A randomized, double-blind, placebo-controlled trial. SETTING: Seven hospitals in Italy. PATIENTS: A total of 174 white treatment-naive adults with type 2 diabetes and a glycated hemoglobin (HbA(1c)) level higher than 7.5%. INTERVENTION: After an open-label run-in period of 8 ± 2 months with metformin, patients were randomized to take exenatide (5 µg twice/day for the first 4 weeks, 10 µg twice/day thereafter) or a placebo volume equivalent for 12 months. MEASUREMENTS AND MAIN RESULTS: Body mass index, HbA(1c), fasting plasma glucose, postprandial plasma glucose, fasting plasma insulin (FPI), homeostasis model assessment insulin resistance index, homeostasis model assessment ß-cell function index (HOMA-ß), fasting plasma proinsulin (FPPr), proinsulin-to-fasting plasma insulin ratio (Pr:FPI ratio), C-peptide, glucagon, vaspin, chemerin, and resistin were evaluated at baseline, at randomization, and at 3, 6, 9, and 12 months. Patients also underwent a combined euglycemic, hyperinsulinemic, and hyperglycemic clamp with subsequent arginine stimulation to assess insulin sensitivity and insulin secretion. HbA(1c) was significantly improved with exenatide plus metformin compared with placebo plus metformin. Exenatide plus metformin was also significantly more effective than placebo plus metformin in increasing HOMA-ß C-peptide, and all measures of ß-cell function after the euglycemic hyperinsulinemic and hyperglycemic clamp. We observed that exenatide plus metformin also reduced resistin compared with placebo plus metformin. No variations in vaspin and chemerin were noted in group-to-group comparisons. We observed a significant correlation between M value increase, an index of insulin sensitivity, and a decrease in inflammatory parameters in the exenatide plus metformin group. CONCLUSIONS: The combination of exenatide plus metformin was more effective than metformin alone in improving glycemic control, ß-cell function, and inflammatory parameters.

A randomized, double-blind, comparative therapy evaluating sitagliptin versus glibenclamide in type 2 diabetes patients already treated with pioglitazone and metformin: a 3-year study.

OBJECTIVES: This study evaluated if triple oral therapy can be useful in improving glycemic control compared with metformin monotherapy and with a metformin and pioglitazone combination. Furthermore, we also compared a triple metformin+pioglitazone+glibenclamide combination with a metformin+pioglitazone+sitagliptin one. SUBJECTS AND METHODS: After a 2-year run-in therapy-augmenting phase with metformin and pioglitazone, 453 overweight, type 2 diabetes patients were randomized to 1 year of sitagliptin versus 1 year of glibenclamide to evaluate, as the primary outcome, the variation of ß-cell function both in a fasting state and after an euglycemic hyperinsulinemic and hyperglycemic clamp. As secondary outcomes we evaluated glycemic control and insulin resistance. RESULTS: Both the triple therapy combinations were more effective in reducing glycated hemoglobin compared with metformin monotherapy and with dual therapy metformin+pioglitazone. Fasting plasma insulin level and the homeostasis model assessment insulin resistance index were significantly increased by triple therapy with glibenclamide and decreased by the one with sitagliptin. Although sitagliptin did not change the homeostasis model assessment ß-function index, this value was significantly increased by glibenclamide. The fasting plasma proinsulin level was decreased by sitagliptin. Triple therapy with sitagliptin greatly improved ß-cell function measures compared with the glibenclamide one and also compared with metformin monotherapy and with the metformin+pioglitazone combination. CONCLUSIONS: Dual combination therapy is more effective than monotherapy in improving glycemic control. When double therapy is not enough to reach an adequate glycemic control, sitagliptin should be preferred to glibenclamide as the third agent because of its positive effect on ß-cells.

Exenatide or glimepiride added to metformin on metabolic control and on insulin resistance in type 2 diabetic patients.

The aim of this study was to evaluate the effect of exenatide compared to glimepiride on body weight, glycemic control and insulin resistance in type 2 diabetic patients taking metformin. One hundred and eleven patients with uncontrolled type 2 diabetes mellitus and intolerant to metformin at the highest dosages (2500-3000 mg/day) were enrolled in this study. Patients were randomized to receive exenatide 5 µg twice a day or glimepiride 1mg three times a day and titrated after 1 month to exenatide 10 µg twice a day or glimepiride 2mg three times a day for 12 months in a randomized, single-blind, controlled study. We evaluated at the baseline and after 3, 6, 9, and 12 months these parameters: body weight, body mass index (BMI), HbA(1c), glycemic control, fasting plasma insulin, homeostasis model assessment insulin resistance index (HOMA-IR) index, adiponectin, tumor necrosis factor-α, and high sensitivity-C reactive protein. Both treatments gave a similar improvement of glycemic control, without any differences between the two groups. Only exenatide gave a decrease of BMI, insulin resistance parameters such as fasting plasma insulin, HOMA-IR, and adiponectin and a decrease of inflammatory parameters such as tumor necrosis factor-α, and high sensitivity-C reactive protein. Furthermore, the values obtained with exenatide were significantly better than the values recorded with glimepiride. We can conclude that exenatide was better than glimepiride in improving insulin resistance and inflammatory state. Furthermore, adiponectin increase, and tumor necrosis factor-α reduction seem to be related to weight loss obtained with exenatide.

Effects of sitagliptin or metformin added to pioglitazone monotherapy in poorly controlled type 2 diabetes mellitus patients.

The aim of the study was to compare the effects of the addition of sitagliptin or metformin to pioglitazone monotherapy in poorly controlled type 2 diabetes mellitus patients on body weight, glycemic control, beta-cell function, insulin resistance, and inflammatory state parameters. One hundred fifty-one patients with uncontrolled type 2 diabetes mellitus (glycated hemoglobin [HbA(1c)] >7.5%) in therapy with pioglitazone 30 mg/d were enrolled in this study. We randomized patients to take pioglitazone 30 mg plus sitagliptin 100 mg once a day, or pioglitazone 15 mg plus metformin 850 mg twice a day. We evaluated at baseline and after 3, 6, 9, and 12 months these parameters: body weight, body mass index, HbA(1c), fasting plasma glucose (FPG), postprandial plasma glucose (PPG), fasting plasma insulin (FPI), homeostasis model assessment insulin resistance index (HOMA-IR), homeostasis model assessment beta-cell function index, fasting plasma proinsulin (Pr), Pr/FPI ratio, adiponectin, resistin (R), tumor necrosis factor-alpha (TNF-alpha), and high-sensitivity C-reactive protein. A decrease of body weight and body mass index was observed with metformin, but not with sitagliptin, at the end of the study. We observed a comparable significant decrease of HbA(1c), FPG, and PPG and a significant increase of homeostasis model assessment beta-cell function index compared with baseline in both groups without any significant differences between the 2 groups. Fasting plasma insulin, fasting plasma Pr, Pr/FPI ratio, and HOMA-IR values were decreased in both groups even if the values obtained with metformin were significantly lower than the values obtained with sitagliptin. There were no significant variations of ADN, R, or TNF-alpha with sitagliptin, whereas a significant increase of ADN and a significant decrease of R and TNF-alpha values were recorded with metformin. A significant decrease of high-sensitivity C-reactive protein value was obtained in both groups without any significant differences between the 2 groups. There was a significant correlation between HOMA-IR decrease and ADN increase, and between HOMA-IR decrease and R and TNF-alpha decrease in pioglitazone plus metformin group after the treatment. The addition of both sitagliptin or metformin to pioglitazone gave an improvement of HbA(1c), FPG, and PPG; but metformin led also to a decrease of body weight and to a faster and better improvement of insulin resistance and inflammatory state parameters, even if sitagliptin produced a better protection of beta-cell function.