Background: Treatment with the dipeptidyl peptidase-4 inhibitors (DPP4i) and angiotensin receptor blockers (ARBs) in patients with type 2 diabetic nephropathy (DN) has not been well characterized. This study aimed to assess the renoprotection of this combined treatment in DN patients. Methods: A total of 159 type 2 DN patients from 2013 to 2015 were enrolled retrospectively from a prospective DN cohort at the National Clinical Research Center of Kidney Diseases, Jinling Hospital (China). Fifty-seven patients received DPP4i and ARB treatment, and 102 patients were treated with ARBs alone. All patients were followed up for at least 12 months. Statistical analyses were performed using Stata version 12.0. Results: There were no significant differences at baseline for age, sex, body mass index, duration of diabetes, fasting blood glucose (FBG), hemoglobin A1c (HbA1c), and estimated glomerular filtration rate (eGFR) between the two groups. Antihypertensive and antidiabetic medication use was similar in each group except calcium channel antagonists (P = 0.032). No significant changes in FBG and HbA1c were observed in the two groups after treatment. The eGFR decreased slower in the DPP4i + ARB group than in the ARB group at 12 months (Δ12 months: -2.48 ± 13.86 vs. -6.81 ± 12.52 ml·min·1.73m, P = 0.044). In addition, proteinuria was decreased further in the DPP4i + ARB group than in the ARB group after 24 months of treatment (Δ24 months: -0.18 [-1.00, 0.17] vs. 0.32 [-0.35, 0.88], P = 0.031). There were 36 patients with an eGFR decrease of more than 30% over 24 months. After adjusting for FBG, HbA1c, and other risk factors, DPP4i + ARB treatment was still associated with a reduced incidence of an eGFR decrease of 20% or 30%. Conclusions The combined treatment of DPP4i and ARBs is superior to ARBs alone, as evidenced by the greater proteinuria reduction and lower eGFR decline. In addition, the renoprotection of DPP4i combined with ARBs was independent of glycemic control.
Aged ; Angiotensin Receptor Antagonists ; therapeutic use ; Diabetic Nephropathies ; drug therapy ; Dipeptidyl-Peptidase IV Inhibitors ; therapeutic use ; Female ; Humans ; Losartan ; therapeutic use ; Male ; Middle Aged ; Prospective Studies ; Retrospective Studies

Despite strict pre- and post-transplantation screening, the incidence of new-onset diabetes after transplantation (NODAT) remains as high as 60%. This complication affects the risk of cardiovascular events and patient and graft survival rates. Thus, reducing the impact of NODAT could improve overall transplant success. The pathogenesis of NODAT is multifactorial, and both modifiable and nonmodifiable risk factors have been implicated. Monitoring and controlling the blood glucose profile, implementing multidisciplinary care, performing lifestyle modifications, using a modified immunosuppressive regimen, administering anti-metabolite agents, and taking a conventional antidiabetic approach may diminish the incidence of NODAT. In addition to these preventive strategies, inhibition of dipeptidyl peptidase-4 (DPP4) by the gliptin family of drugs has recently gained considerable interest as therapy for type 2 diabetes mellitus and NODAT. This review focuses on the role of DPP4 inhibitors and discusses recent literature regarding management of NODAT.
Animals ; Blood Glucose/drug effects/metabolism ; Diabetes Mellitus/diagnosis/*drug therapy/enzymology/etiology ; Dipeptidyl Peptidase 4/*metabolism ; Dipeptidyl-Peptidase IV Inhibitors/*therapeutic use ; Humans ; Organ Transplantation/*adverse effects ; Risk Assessment ; Risk Factors ; Treatment Outcome

Dipeptidylpeptidase (DPP) 4, also known as CD26, is an enzyme present on the surface of a number of different cell types. It is also found within cells and as a soluble protein in body fluids. It can specifically truncate proteins at the penultimate N-terminus residue for some amino acids, such as alanine, proline, serine, and perhaps others. DPP4 has been implicated in regulating the in vitro and in vivo functional activities of a number of hematopoietically active molecules, and this information, along with that on inhibition of DPP4, has been studied in efforts to enhance hematopoietic cell transplantation (HCT), hematopoiesis after stress in mouse models, and in the clinical setting of single-unit cord blood (CB) HCT. This article reviews the current status of this compound's effects on regulatory proteins, the field of CB HCT, a potential role for modulating DPP4 activity in enhancing single-unit CB HCT in adults, and future aspects in context of other cellular therapies and the area of regenerative medicine.
Animals ; *Cord Blood Stem Cell Transplantation ; Dipeptidyl Peptidase 4/*metabolism ; Dipeptidyl-Peptidase IV Inhibitors/*therapeutic use ; Hematopoiesis/*drug effects ; Hematopoietic Stem Cells/*drug effects/enzymology ; Humans ; Regenerative Medicine/*methods ; Signal Transduction/drug effects

BACKGROUNDDipeptidyl peptidase-IV (DPP-4) inhibitors are now used to improve postprandial glycemic control in type 2 diabetes. However, their effects on hepatic glucose production (HGP) in obesity are not clear. This study was designed to test the hypothesis that gluconeogenesis and HGP can be modulated by DPP-4 inhibitors in obesity.

METHODSSprague Dawley male rats were divided into four groups, each on a different diet: general rat chow, n = 10 (G); G + sitagliptin, n = 10; high fat chow (obesity), n = 10 (55% fat calories, HFO); HFO + sitagliptin, n = 10. After 10 weeks, the rats were fasted overnight and glucose metabolism was determined using 3-(3)H-glucose and (14)C-glycerol as tracers.

RESULTSGlycerol rate of appearance (P < 0.00001), plasma glycerol (P < 0.05) and free fatty acid (FFA) (P < 0.05) concentrations, and HGP (P < 0.05) were decreased in HFO + sitagliptin group compared with HFO group, but there was no significant difference between G and G + sitagliptin groups (P > 0.05). Gluconeogenesis in HFO group was five times of that in G rats (P < 0.01), but was significantly declined in HFO + sitagliptin group (P < 0.0001).

CONCLUSIONSGluconeogenesis and HGP were inhibited by sitagliptin in high fat-induced obese rats due to decreased glycerol availability, which was a result of reduced glycerol release from adipose tissues. The finding suggests that sitagliptin is potentially useful for controlling fasting glucose in obesity, thereby delaying or preventing the development of diabetes.

Animals ; Dipeptidyl-Peptidase IV Inhibitors ; therapeutic use ; Glucose ; metabolism ; Liver ; drug effects ; metabolism ; Male ; Obesity ; drug therapy ; metabolism ; Pyrazines ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Sitagliptin Phosphate ; Triazoles ; therapeutic use

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease and it represents the hepatic manifestation of metabolic syndrome, which includes type 2 diabetes mellitus (T2DM), dyslipidemia, central obesity and hypertension. Glucagon-like peptide-1 (GLP-1) analogues and dipeptidyl peptidase-4 (DPP-4) inhibitors were widely used to treat T2DM. These agents improve glycemic control, promote weight loss and improve lipid metabolism. Recent studies have demonstrated that the GLP-1 receptor (GLP-1R) is present and functional in human and rat hepatocytes. In this review, we present data from animal researches and human clinical studies that showed GLP-1 analogues and DPP-4 inhibitors can decrease hepatic triglyceride (TG) content and improve hepatic steatosis, although some effects could be a result of improvements in metabolic parameters. Multiple hepatocyte signal transduction pathways and mRNA from key enzymes in fatty acid metabolism appear to be activated by GLP-1 and its analogues. Thus, the data support the need for more rigorous prospective clinical trials to further investigate the potential of incretin therapies to treat patients with NAFLD.
Animals ; Clinical Trials as Topic ; Dipeptidyl-Peptidase IV Inhibitors ; pharmacology ; therapeutic use ; Glucagon-Like Peptide 1 ; agonists ; Humans ; Hypoglycemic Agents ; pharmacology ; therapeutic use ; Lipid Metabolism ; drug effects ; Non-alcoholic Fatty Liver Disease ; drug therapy ; metabolism ; Triglycerides ; metabolism

We investigated characteristics associated with the efficacy of dipeptidyl peptidase-4 inhibitors (DPP4i) in Korean patients with type 2 diabetes. We reviewed medical records of 477 patients who had taken sitagliptin or vildagliptin longer than 40 weeks. Response to DPP4i was evaluated with HbA1c change after therapy (DeltaHbA1c). The Student's t-test between good responders (GR: DeltaHbA1c > 1.0%) and poor responders (PR: DeltaHbA1c < 0.5%), a correlation analysis among clinical parameters, and a linear multivariate regression analysis were performed. The mean age was 60 yr, duration of diabetes 11 yr and HbA1c was 8.1%. Baseline fasting plasma glucose (FPG), HbA1c, C-peptide, and creatinine were significantly higher in the GR compared to the PR. Duration of diabetes, FPG, HbA1c, C-peptide and creatinine were significantly correlated with DeltaHbA1c. In the multivariate analysis, age (r2 = 0.006), duration of diabetes (r2 = 0.019), HbA1c (r2 = 0.296), and creatinine levels (r2 = 0.024) were independent predictors for the response to DPP4i. Body mass index and insulin resistance were not associated with the response to DPP4i. In conclusion, better response to DPP4i would be expected in Korean patients with type 2 diabetes who have higher baseline HbA1c and creatinine levels with shorter duration of diabetes.
Adamantane/*analogs & derivatives/therapeutic use ; Blood Glucose/analysis ; Body Mass Index ; C-Peptide/analysis ; Creatinine/blood ; Diabetes Mellitus, Type 2/*drug therapy/pathology ; Dipeptidyl-Peptidase IV Inhibitors/*therapeutic use ; Hemoglobin A, Glycosylated/analysis ; Humans ; Insulin Resistance ; Male ; Middle Aged ; Multivariate Analysis ; Nitriles/*therapeutic use ; Pyrazines/*therapeutic use ; Pyrrolidines/*therapeutic use ; Retrospective Studies ; Triazoles/*therapeutic use

The vascular endothelial function is impaired in the very early stage of atherosclerosis in diabetic patients. The goal of this study was to identify the mechanism underlying the improvement in vascular endothelial function by sitagliptin in type 2 diabetes mellitus patients. This study was an open-labeled prospective observational single arm trial. Forty patients were treated with 50 mg of sitagliptin once daily for 12-weeks. The flow-mediated dilation (FMD) and plasma adiponectin were measured at baseline and 12 weeks after initiating treatment. The %FMD was significantly increased after treatment (4.13 +/- 1.59 vs 5.12 +/- 1.55, P < 0.001), whereas the nitroglycerin-mediated dilation (NMD) did not change. The plasma adiponectin levels significantly increased (13.0 +/- 11.3 vs 14.3 +/- 12.8, P < 0.001). The changes in the FMD were significantly correlated with those of the plasma adiponectin (r = 0.322, P < 0.05). A multivariate linear regression analysis demonstrated that the improvement in the FMD is associated with the plasma adiponectin (P < 0.05). The treatment of type 2 diabetes mellitus patients with sitagliptin reverses vascular endothelial dysfunction, as evidenced by increase in the FMD, and improvement of the adiponectin levels (UMIN Clinical Trials Registry System as trial ID UMIN000004236).
Adiponectin/blood ; Aged ; Aged, 80 and over ; Atherosclerosis/complications/drug therapy ; Diabetes Mellitus, Type 2/complications/*drug therapy ; Dipeptidyl-Peptidase IV Inhibitors/pharmacology/*therapeutic use ; Drug Administration Schedule ; Endothelium, Vascular/*drug effects/physiopathology ; Female ; Humans ; Male ; Middle Aged ; Nitroglycerin/therapeutic use ; Prospective Studies ; Pyrazines/pharmacology/*therapeutic use ; Regression Analysis ; Triazoles/pharmacology/*therapeutic use ; Vasodilation/drug effects ; Vasodilator Agents/therapeutic use

The vascular endothelial function is impaired in the very early stage of atherosclerosis in diabetic patients. The goal of this study was to identify the mechanism underlying the improvement in vascular endothelial function by sitagliptin in type 2 diabetes mellitus patients. This study was an open-labeled prospective observational single arm trial. Forty patients were treated with 50 mg of sitagliptin once daily for 12-weeks. The flow-mediated dilation (FMD) and plasma adiponectin were measured at baseline and 12 weeks after initiating treatment. The %FMD was significantly increased after treatment (4.13 +/- 1.59 vs 5.12 +/- 1.55, P < 0.001), whereas the nitroglycerin-mediated dilation (NMD) did not change. The plasma adiponectin levels significantly increased (13.0 +/- 11.3 vs 14.3 +/- 12.8, P < 0.001). The changes in the FMD were significantly correlated with those of the plasma adiponectin (r = 0.322, P < 0.05). A multivariate linear regression analysis demonstrated that the improvement in the FMD is associated with the plasma adiponectin (P < 0.05). The treatment of type 2 diabetes mellitus patients with sitagliptin reverses vascular endothelial dysfunction, as evidenced by increase in the FMD, and improvement of the adiponectin levels (UMIN Clinical Trials Registry System as trial ID UMIN000004236).
Adiponectin/blood ; Aged ; Aged, 80 and over ; Atherosclerosis/complications/drug therapy ; Diabetes Mellitus, Type 2/complications/*drug therapy ; Dipeptidyl-Peptidase IV Inhibitors/pharmacology/*therapeutic use ; Drug Administration Schedule ; Endothelium, Vascular/*drug effects/physiopathology ; Female ; Humans ; Male ; Middle Aged ; Nitroglycerin/therapeutic use ; Prospective Studies ; Pyrazines/pharmacology/*therapeutic use ; Regression Analysis ; Triazoles/pharmacology/*therapeutic use ; Vasodilation/drug effects ; Vasodilator Agents/therapeutic use

OBJECTIVE: To observe the clinical efficacy of sitagliptin plus insulin on patients with brittle diabetes and to determine the effect of the combined therapy on glucagon secretion.
 METHODS: This randomized, double-blinded and placebo-controlled trial included 30 patients with brittle diabetes. Participants were randomly assigned (1:1) to receive the treatment of either sitagliptin plus insulin or placebo plus insulin for 12 weeks. The blood glucose, hemoglobin A1c, insulin dose, C-peptide, glucagon, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and other parameters were determined.
 RESULTS: After 12 weeks of treatment, blood glucose was controlled better by sitagliptin plus insulin (P<0.01). The patients had significantly lower glucose variability indices, lower daily insulin requirement and hemoglobin A1c in the group of sitagliptin plus insulin (P<0.01). After steamed bun test, past-meal GLP-1 levels at 30 min were higher (P<0.01) while GIP levels were lower (P<0.01), with glucagon suppression in the sitagliptin plus insulin group. No significant change was observed at any time point in placebo plus insulin group.
 CONCLUSION Sitagliptin significantly decreases blood glucose level and blood glucose fluctuation, which may contribute to the ability of sitagliptin in decreasing glucagon secretion.
Blood Glucose ; analysis ; C-Peptide ; blood ; Diabetes Mellitus, Type 1 ; drug therapy ; Dipeptidyl-Peptidase IV Inhibitors ; Double-Blind Method ; Drug Therapy, Combination ; Gastric Inhibitory Polypeptide ; blood ; Glucagon ; blood ; Glucagon-Like Peptide 1 ; blood ; Glycated Hemoglobin A ; analysis ; Humans ; Hypoglycemic Agents ; administration & dosage ; therapeutic use ; Insulin ; administration & dosage ; therapeutic use ; Sitagliptin Phosphate ; administration & dosage ; therapeutic use