sitagliptin-phosphate and Metabolic-Syndrome

Few prospective studies have compared the cardiovascular benefits of sodium-glucose cotransporter-2 (SGLT2) inhibitors and dipeptidyl peptidase 4 (DPP-4) inhibitors. We aimed to clarify the efficacy of dapagliflozin versus sitagliptin for modulating cardiometabolic risk factors including high glycated hemoglobin (HbA1c) levels, hypoglycemia, and body weight.. This prospective, randomized, open-label, blinded-endpoint, parallel-group trial enrolled 340 Japanese patients with early-stage type 2 diabetes receiving metformin alone or no glucose-lowering agents, who were randomized to receive dapagliflozin or sitagliptin for 24 weeks. The primary endpoint was the proportion of patients who achieved the composite endpoint of HbA1c level maintenance < 7.0% (53 mmol/mol), avoidance of hypoglycemia (maintenance of sensor glucose ≥ 3.0 mmol/L or ≥ 54 mg/dL), and ≥ 3.0% body weight loss from baseline. Secondary endpoints included components of the primary endpoint, other metabolic indices, and glucose variability indices measured using flash glucose monitoring.. Compared to sitagliptin, dapagliflozin was significantly more effective at improving cardiometabolic risk factors, suggesting that SGLT2 inhibitors might be more suitable than DPP-4 inhibitors for preventing cardiovascular events in patients with early-stage but inadequately controlled type 2 diabetes. Trial registration Trial number, UMIN000028014; registered on June 30, 2017.

Topics: Aged; Benzhydryl Compounds; Biomarkers; Blood Glucose; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Female; Glucosides; Glycated Hemoglobin; Humans; Japan; Male; Metabolic Syndrome; Middle Aged; Prospective Studies; Risk Assessment; Risk Factors; Sitagliptin Phosphate; Sodium-Glucose Transporter 2 Inhibitors; Time Factors; Treatment Outcome; Weight Loss

We aimed to evaluate the efficacy and safety profile of lobeglitazone compared with sitagliptin as an add-on to metformin in patients with type 2 diabetes as well as other components of metabolic syndrome. Patients inadequately controlled by metformin were randomly assigned to lobeglitazone (0.5 mg, n = 121) or sitagliptin (100 mg, n = 126) for 24 weeks. The mean changes in HbA1c of the lobeglitazone and sitagliptin groups were -0.79% and -0.86%, respectively; the between-group difference was 0.08% (95% confidence interval, -0.14% to 0.30%), showing non-inferiority. The proportion of patients having two or more factors of other metabolic syndrome components decreased to a greater extent in the lobeglitazone group than in the sitagliptin group (-11.9% vs. -4.8%; P < .0174). Favourable changes in the lipid metabolism were also observed with lobeglitazone, which had a similar safety profile to sitagliptin. Lobeglitazone was comparable with sitagliptin as an add-on to metformin in terms of efficacy and safety.

Topics: Blood Glucose; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Metabolic Syndrome; Metformin; Pyrimidines; Sitagliptin Phosphate; Thiazolidinediones; Treatment Outcome

Anti-inflammatory glucocorticoid (GC) therapy often induces hyperglycemia due to insulin resistance and islet-cell dysfunction. Incretin-based therapies may preserve glucose tolerance and pancreatic islet-cell function. In this study, we hypothesized that concomitant administration of the dipeptidyl peptidase-4 inhibitor sitagliptin and prednisolone in men at high risk to develop type 2 diabetes could protect against the GC-induced diabetogenic effects.. Men with the metabolic syndrome but without diabetes received prednisolone 30  mg once daily plus sitagliptin 100  mg once daily (n=14), prednisolone (n=12) or sitagliptin alone (n=14) or placebo (n=12) for 14 days in a double-blind 2 × 2 randomized-controlled study. Glucose, insulin, C-peptide, and glucagon were measured in the fasted state and following a standardized mixed-meal test. β-cell function parameters were assessed both from a hyperglycemic-arginine clamp procedure and from the meal test. Insulin sensitivity (M-value) was measured by euglycemic clamp.. Prednisolone increased postprandial area under the curve (AUC)-glucose by 17% (P<0.001 vs placebo) and postprandial AUC-glucagon by 50% (P<0.001). Prednisolone reduced 1st and 2nd phase glucose-stimulated- and combined hyperglycemia-arginine-stimulated C-peptide secretion (all P ≤ 0.001). When sitagliptin was added, both clamp-measured β-cell function (P=NS for 1st and 2nd phase vs placebo) and postprandial hyperglucagonemia (P=NS vs placebo) remained unaffected. However, administration of sitagliptin could not prevent prednisolone-induced increment in postprandial glucose concentrations (P<0.001 vs placebo). M-value was not altered by any treatment.. Fourteen-day treatment with high-dose prednisolone impaired postprandial glucose metabolism in subjects with the metabolic syndrome. Concomitant treatment with sitagliptin improved various aspects of pancreatic islet-cell function, but did not prevent deterioration of glucose tolerance by GC treatment.

Topics: Blood Glucose; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Double-Blind Method; Fasting; Glucocorticoids; Glucose Intolerance; Humans; Insulin Resistance; Islets of Langerhans; Male; Metabolic Syndrome; Middle Aged; Postprandial Period; Prednisolone; Pyrazines; Sitagliptin Phosphate; Triazoles

We hypothesize that type 2 diabetic patients with different phenotypes may show different response to incretin-based therapies. Therefore, we tested whether the presence of metabolic syndrome (MS) influences glycemic response to these drugs. We prospectively followed 211 patients, treated with the GLP-1 analog exenatide (n = 102) or a DPP-4 inhibitor (n = 109) for at least 4 months. Treatment was decided on clinical grounds. We collected baseline data (age, sex, BMI, waist, systolic and diastolic blood pressure, lipid profile, data on diabetic complications and concomitant treatment) and HbA1c at subsequent visits. Patients were divided into groups according to the presence/absence of MS. Compared to patients on exenatide, patients on DPP-4 inhibitors were older and had lower BMI, waist, diastolic blood pressure, fasting plasma glucose, and HbA1c. At means of baseline values, HbA1c reduction was similar in patients treated with exenatide or DPP-4 inhibitors. Patients on exenatide showed significantly higher HbA1c reduction if they had MS (-1.55 ± 0.22%; n = 88) than if they had not (-0.34 ± 0.18%; P = 0.002). Conversely, patients on DPP-4 inhibitors showed significantly lower HbA1c reduction if they had MS (-0.60 ± 0.12%; n = 73) than if they had not (-1.50 ± 0.24%; P < 0.001). Type of MS definition (ATP-III, IDF or WHO) poorly influenced these trends. The interaction between type of therapy (exenatide vs. DPP-4 inhibitors) and MS remained significant after adjusting for age, baseline HbA1c, BMI, and concomitant medications. In conclusion, the presence of MS appears to modify the response to incretin-based therapies. Given the non-randomized nature of this study, these data need to be replicated.

Topics: Adamantane; Aged; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Exenatide; Female; Glucagon-Like Peptide 1; Humans; Hypoglycemic Agents; Incretins; Male; Metabolic Syndrome; Middle Aged; Nitriles; Peptides; Prognosis; Pyrazines; Pyrrolidines; Sitagliptin Phosphate; Treatment Outcome; Triazoles; Venoms; Vildagliptin

Dipeptidyl peptidase-IV inhibitors improve glucose homeostasis in type 2 diabetics by inhibiting degradation of the incretin hormones. Dipeptidyl peptidase-IV inhibition also prevents the breakdown of the vasoconstrictor neuropeptide Y and, when angiotensin-converting enzyme (ACE) is inhibited, substance P. This study tested the hypothesis that dipeptidyl peptidase-IV inhibition would enhance the blood pressure response to acute ACE inhibition. Subjects with the metabolic syndrome were treated with 0 mg of enalapril (n=9), 5 mg of enalapril (n=8), or 10 mg enalapril (n=7) after treatment with sitagliptin (100 mg/day for 5 days and matching placebo for 5 days) in a randomized, cross-over fashion. Sitagliptin decreased serum dipeptidyl peptidase-IV activity (13.08±1.45 versus 30.28±1.76 nmol/mL/min during placebo; P≤0.001) and fasting blood glucose. Enalapril decreased ACE activity in a dose-dependent manner (P<0.001). Sitagliptin lowered blood pressure during enalapril (0 mg; P=0.02) and augmented the hypotensive response to 5 mg of enalapril (P=0.05). In contrast, sitagliptin attenuated the hypotensive response to 10 mg of enalapril (P=0.02). During sitagliptin, but not during placebo, 10 mg of enalapril significantly increased heart rate and plasma norepinephrine concentrations. There was no effect of 0 or 5 mg of enalapril on heart rate or norepinephrine after treatment with either sitagliptin or placebo. Sitagliptin enhanced the dose-dependent effect of enalapril on renal blood flow. In summary, sitagliptin lowers blood pressure during placebo or submaximal ACE inhibition; sitagliptin activates the sympathetic nervous system to diminish hypotension when ACE is maximally inhibited. This study provides the first evidence for an interactive hemodynamic effect of dipeptidyl peptidase-IV and ACE inhibition in humans.

Topics: Adult; Aldosterone; Angiotensin-Converting Enzyme Inhibitors; Blood Glucose; Blood Pressure; Diabetes Mellitus, Type 2; Dipeptidyl Peptidase 4; Dose-Response Relationship, Drug; Double-Blind Method; Drug Interactions; Drug Therapy, Combination; Enalapril; Female; Heart Rate; Hemodynamics; Humans; Insulin; Male; Metabolic Syndrome; Middle Aged; Peptidyl-Dipeptidase A; Prospective Studies; Pyrazines; Renal Circulation; Sitagliptin Phosphate; Sodium; Triazoles

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, is a risk factor for endothelial dysfunction, a common pathophysiological denominator for both atherogenesis and cardiac fibrosis. We aimed to investigate whether the cardioprotective and antifibrotic effects of incretin drugs, exenatide and sitagliptin, may be associated with their ability to affect circulating and cardiac ADMA metabolism. Normal and fructose-fed rats were treated with sitagliptin (5.0/10 mg/kg) or exenatide (5/10 µg/kg) for 4 weeks. The following methods were used: LC-MS/MS, ELISA, Real-Time-PCR, colorimetry, IHC and H&E staining, PCA and OPLS-DA projections. Eight-week fructose feeding resulted in an increase in plasma ADMA and a decrease in NO concentration. Exenatide administration into fructose-fed rats reduced the plasma ADMA level and increased NO level. In the heart of these animals exenatide administration increased NO and PRMT1 level, reduced TGF-ß1, α-SMA levels and COL1A1 expression. In the exenatide treated rats renal DDAH activity positively correlated with plasma NO level and negatively with plasma ADMA level and cardiac α-SMA concentration. Sitagliptin treatment of fructose-fed rats increased plasma NO concentration, reduced circulating SDMA level, increased renal DDAH activity and reduced myocardial DDAH activity. Both drugs attenuated the myocardial immunoexpression of Smad2/3/P and perivascular fibrosis. In the metabolic syndrome condition both sitagliptin and exenatide positively modulated cardiac fibrotic remodeling and circulating level of endogenous NOS inhibitors but had no effects on ADMA levels in the myocardium.

Topics: Amidohydrolases; Animals; Arginine; Biomarkers; Chromatography, Liquid; Dipeptidyl-Peptidase IV Inhibitors; Exenatide; Fibrosis; Fructose; Glucagon-Like Peptide 1; Hypoglycemic Agents; Metabolic Syndrome; Nitric Oxide; Protease Inhibitors; Rats; Sitagliptin Phosphate; Tandem Mass Spectrometry

Nonalcoholic fatty liver disease (NAFLD) is a common cause of clinical liver dysfunction and an important prepathological change of liver cirrhosis. Central obesity, type 2 diabetes mellitus, dyslipidemia, and metabolic syndrome are the major risk factors for NAFLD. Sitagliptin (Sig) is a novel hypoglycemic agent that improves blood glucose levels by increasing the level of active incretin. Sig has been shown to prevent the development of fatty livers in mice on a fructose-rich diet. The purpose of this study was to observe the efficacy of Sig on NAFLD in type 2 diabetic mice.. The diet-induced obesity mouse model was established, and the diabetic mice were screened by an intraperitoneal glucose tolerance trial. The mice were randomly divided into four groups for 8 weeks of intervention: high-fat diet (HFD) group, Sig group, metformin (Met) group, and Sig+Met group. After the intervention, the liver function indexes as well as the blood glucose and blood lipid levels of the mice were measured. In addition, the wet weight of the liver was measured; the pathological sections of the liver tissues were stained to observe the hepatocyte fatty degeneration, inflammation, necrosis, and fibrosis; and the hepatic histological injury was recorded as the NAFLD activity score (NAS).. Compared with the normal control group, the body weight, liver weight, blood glucose level, insulin resistance (IR), blood lipid level, and transaminase level of the mice in the HFD group were significantly increased, showing typical metabolic syndrome. After treatment with Sig and/or Met, the mice gained less weight, had lower levels of blood glucose, triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and transaminase, and had improved IR compared with the HFD group. The liver pathological NASs in the Sig group (P=0.01), Met group (P=0.028), and Sig+Met group (P<0.001) were lower than those in the HFD group (P<0.05), suggesting that the use of the two drugs alone or in combination can improve the state of liver inflammation. In terms of fibrosis, there was no fibrosis in the control group but there was significant fibrosis in the HFD group (P<0.001). There was no significant difference between the drug intervention groups and the HFD group, indicating that the drug therapy (Sig and/or Met) did not significantly improve the pre-existing fibrosis.. Our experiment proved that Sig can improve NAFLD, including improvement of the serum transaminase level, hepatic pathological inflammation level, and hepatocyte adiposis, suggesting that Sig may play a role by improving glucose and lipid metabolism, reducing the body weight and liver weight, improving insulin sensitivity, and inhibiting fatty liver inflammation. Sig may be a new direction for the treatment of patients with a nonalcoholic fatty liver and diabetes, delaying the progression of NAFLD.

Topics: Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet, High-Fat; Humans; Inflammation; Insulin Resistance; Liver Cirrhosis; Metabolic Syndrome; Metformin; Mice; Non-alcoholic Fatty Liver Disease; Obesity; Sitagliptin Phosphate; Transaminases

Chronic consumption of unhealthy diet and sedentary lifestyle induces fatty liver and metabolic complications. Adipocytes get overloaded with lipid succeeding low-grade inflammation and disrupting adipokine release. This research aims to investigate the effect of sitagliptin on white adipose tissue inflammation, adipokine level, metabolic syndrome, and fatty liver through 5' adenosine monophosphate-activated protein kinase (AMPK) pathway. In sixteen weeks of the experimental protocol, Swiss albino mice were kept in a standard environment and were fed 60% high-fat diet and 20% fructose water (HFFW) where they developed metabolic syndrome features, adipose tissue inflammation, and altered adipokine profile. Sitagliptin was administered for the last eight weeks. They were allocated to following six groups, control diet with regular water (1), HFFW only (2), HFFW and metformin 100 mg/kg (3), HFFW and sitagliptin 10 mg/kg (4), HFFW and sitagliptin 20 mg/kg (5), and HFFW and sitagliptin 30 mg/kg (6). Fasting serum insulin (FSI), glucagon-like peptide-1 (GLP-1), adipokines (adiponectin and leptin), serum lipid profile, hepatic lipid content, and white adipose tissue inflammation were assessed. Protein expression of P-AMPK, P-Acetyl co-a carboxylase (ACC), and mRNA expression of fatty acid metabolism genes were also evaluated in the liver. Sitagliptin significantly and effectively reversed metabolic syndrome complexity. FSI and GLP-1 levels were improved. A significant reduction in hepatic lipid content and oxidative stress was also observed. Also, sitagliptin significantly ameliorated adipose tissue inflammation and adiponectin levels at 20 mg/kg and 30 mg/kg. P-AMPK and P-ACC expression increased significantly. Moreover, expression of fatty acid synthesis genes was down-regulated, and fatty acid oxidation genes were up-regulated. Sitagliptin significantly ameliorated obesity-induced adipose tissue inflammation, metabolic syndrome, and fatty liver via regulation of adiponectin and AMPK levels in obese mice. Also, increased GLP-1 levels would have induced insulin-independent effects on adipose tissue and liver.

Topics: Adiponectin; Adipose Tissue, White; AMP-Activated Protein Kinases; Animals; Fatty Liver; Inflammation; Lipid Metabolism; Liver; Male; Metabolic Syndrome; Mice; Oxidative Stress; Sitagliptin Phosphate

The present study aimed to evaluate the effect of trigonelline (TRG) on the hepatic complications associated with high-fat high-fructose (HFHF) diet-induced insulin resistance (IR) in rats. IR was induced by giving a saturated fat diet and 10% fructose in drinking water to rats for 8 weeks. Insulin-resistant rats were orally treated with TRG (50 and 100 mg/kg), sitagliptin (SIT; 5 mg/kg), or a combination of TRG (50 mg/kg) and SIT (5 mg/kg) for 14 days. Liver homogenates were used for assessment of hepatic lipids, oxidative stress biomarkers, and inflammatory cytokines. Histopathological and DNA cytometry examinations were carried out for hepatic and pancreatic tissues. Hepatic tissues were examined using Fourier-transform infrared spectroscopy for assessment of any molecular changes. Results of the present study revealed that oral treatment of insulin-resistant rats with TRG or TRG in combination with SIT significantly decreased homeostatic model assessment of IR, hepatic lipids, oxidative stress biomarkers, and the inflammatory cytokines. TRG or TRG in combination with SIT ameliorated the histopathological, DNA cytometry, and molecular alterations induced by a HFHF diet. Finally, it can be concluded that TRG has beneficial effects on the hepatic complications associated with IR due to its hypoglycemic effect and antioxidant potential.

Topics: Alkaloids; Animals; Antioxidants; Biomarkers; Blood Glucose; Cytokines; Diet, Carbohydrate Loading; Diet, High-Fat; Dipeptidyl-Peptidase IV Inhibitors; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Lipids; Liver; Male; Metabolic Syndrome; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Rats; Rats, Wistar; Sitagliptin Phosphate

To compare the effect of different hypoglycemic drugs on laboratory and ultrasonographic markers of non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes not controlled on metformin alone.. Prospective study of diabetic patients treated with metformin in combination with gliclazide, pioglitazone, sitagliptin, exenatide, or liraglutide. NAFLD was assessed by abdominal ultrasound and NAFLD fibrosis score was calculated at baseline and 6 months.. Fifty-eight patients completed 6 months of follow-up: 15 received gliclazide, 13 pioglitazone, 15 sitagliptin, 7 exenatide, and 8 liraglutide. NAFLD affected 57.8% of patients at baseline, and its ultrasonographic course varied depending on changes in weight (P=.009) and waist circumference (P=.012). The proportions of patients who experienced ultrasonographic improvement in the different treatment groups were: 33.3% with gliclazide, 37.5% with pioglitazone, 45.5% with sitagliptin, 80% with exenatide, and 33% with liraglutide (P=.28).. Qualitative ultrasonographic NAFLD improvement in diabetic patients treated with metformin in combination with other hypoglycemic drugs is associated to change over time in weight and waist circumference. Long-term clinical trials are needed to assess whether incretin therapies result in better liver outcomes than other hypoglycemic therapies.

Topics: Aged; Aged, 80 and over; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Exenatide; Female; Gliclazide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Incretins; Lipids; Liraglutide; Liver Function Tests; Male; Metabolic Syndrome; Metformin; Middle Aged; Non-alcoholic Fatty Liver Disease; Peptides; Pilot Projects; Pioglitazone; Prospective Studies; Sitagliptin Phosphate; Thiazolidinediones; Venoms; Waist Circumference

Metabolic syndrome (MetS) is a complex medical disorder characterized by insulin resistance, hypertension, and high risk of coronary disease and stroke. Microvascular rarefaction and endothelial dysfunction have also been linked with MetS, and recent evidence from clinical studies supports the efficacy of incretin-based antidiabetic therapies for vascular protection in diabetes. Previous studies pointed out the importance of dipeptidyl peptidase-4 (DPP-4) inhibition in endothelial cells due to getting protection against metabolic pathologies. We therefore aimed to investigate the acute effects of a DPP-4 inhibitor, sitagliptin, on vascular function in rats with high-sucrose diet-induced MetS. In order to elucidate the mechanisms implicated in the effects of DPP-4 inhibition, we tested the involvement of NO pathway and epigenetic regulation in the MetS. Acute use of sitagliptin protects the vascular function in the rats with MetS in part due to NO pathway via restoring the depressed aortic relaxation responses mediated by receptors. Application of sitagliptin enhanced the depressed phosphorylation levels of both the endothelial NO synthase and the apoptotic status of protein kinase B, known as Akt, in endothelium-intact thoracic aorta from rats with MetS. One-hour application of sitagliptin on aortic rings from rats with MetS also induced remarkable histon posttranslational modifications such as increased expression of H3K27Me3, but not of H3K27Me2, resulting in an accumulation of the H3K27Me3. Our findings suggest that, in addition to its well-known hypoglycemic action, sitagliptin may also have beneficial effects on hyperglycemia-induced vascular changes in an endotheium-dependent manner. These present results with sitagliptin aside from the glycaemic control, may demonstrate its important role in the treatment of patients with MetS.

Topics: Analysis of Variance; Animals; Aorta; Blotting, Western; Dipeptidyl-Peptidase IV Inhibitors; Epigenesis, Genetic; Fluorescent Antibody Technique; Histones; Metabolic Syndrome; Pyrazines; Rats; Sitagliptin Phosphate; Sucrose; Triazoles; Vasodilation

Topics: Cardiovascular Diseases; Cause of Death; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Dose-Response Relationship, Drug; Humans; Kidney Failure, Chronic; Metabolic Syndrome; Pyrazines; Randomized Controlled Trials as Topic; Renal Dialysis; Risk Factors; Sitagliptin Phosphate; Survival Rate; Triazoles

The aim of the present study was to test the effect of sitagliptin and exendin-4 upon metabolic alterations, β-cell mass decrease and hepatic steatosis induced by F (fructose) in rats. Normal adult male Wistar rats received a standard commercial diet without (C) or with 10% (w/v) F in the drinking water (F) for 3 weeks; animals from each group were randomly divided into three subgroups: untreated (C and F) and simultaneously receiving either sitagliptin (CS and FS; 115.2 mg/day per rat) or exendin-4 (CE and FE; 0.35 nmol/kg of body weight, intraperitoneally). Water and food intake, oral glucose tolerance, plasma glucose, triacylglycerol (triglyceride), insulin and fructosamine concentration, HOMA-IR [HOMA (homoeostasis model assessment) for insulin resistance], HOMA-β (HOMA for β-cell function) and liver triacylglycerol content were measured. Pancreas immunomorphometric analyses were also performed. IGT (impaired glucose tolerance), plasma triacylglycerol, fructosamine and insulin levels, HOMA-IR and HOMA-β indexes, and liver triacylglycerol content were significantly higher in F rats. Islet β-cell mass was significantly lower in these rats, due to an increase in the percentage of apoptosis. The administration of exendin-4 and sitagliptin to F animals prevented the development of all the metabolic disturbances and the changes in β-cell mass and fatty liver. Thus these compounds, useful in treating Type 2 diabetes, would also prevent/delay the progression of early metabolic and tissue markers of this disease.

Topics: Animals; Apoptosis; Blood Glucose; Body Weight; Diet; Dipeptidyl-Peptidase IV Inhibitors; Drinking; Drug Evaluation, Preclinical; Eating; Exenatide; Fatty Liver; Fructose; Glucose Tolerance Test; Hypoglycemic Agents; Insulin-Secreting Cells; Male; Metabolic Syndrome; Peptides; Pyrazines; Rats; Rats, Wistar; Sitagliptin Phosphate; Triazoles; Venoms

1. Dipeptidyl peptidase (DPP) IV inhibitors enhance renovascular responses to angiotensin (Ang) II in spontaneously hypertensive rats (SHR), but not Wistar-Kyoto rats. Because DPPIV inhibitors are often used in metabolic syndrome, it is important to determine whether DPPIV inhibition in this setting enhances renovascular responses to AngII. 2. Six-week-old Lean-ZSF1 rats (harbouring SHR genes, but without metabolic syndrome; n = 11) and Obese-ZSF1 rats (harbouring SHR genes and expressing metabolic syndrome; n = 10) were provided food and water ad libitum, and metabolic parameters and renovascular responses to AngII were assessed when the animals were 7 and 8 weeks of age, respectively. 3. At 7 weeks of age, compared with Lean-ZSF1, Obese-ZSF1 demonstrated significant (P < 0.05) increases in bodyweight (262 +/- 8 vs 310 +/- 13 g), plasma glucose (112 +/- 4 vs 153 +/- 9 mg/dL), haemoglobin A1c (4.7 +/- 0.1 vs 5.8 +/- 0.4%), urinary glucose excretion (0.021 +/- 0.003 vs 6.70 +/- 1.80 g/kg bodyweight per 24 h) and urinary protein excretion (100 +/- 7 vs 313 +/- 77 mg/kg bodyweight per 24 h). Mean blood pressure was high (133 +/- 7 mmHg) in both strains. 4. At 8 weeks of age, kidneys were isolated and perfused. In Lean-ZSF1 rats, renovascular responses (i.e. changes in perfusion pressure) to physiological levels of AngII (0.1 nmol/L) were 3.4 +/- 1.3 and 18.2 +/- 5.9 mmHg in untreated (n = 5) and 1 micromol/L sitagliptin-treated (n = 6) kidneys, respectively. In Obese-ZSF1 rats, renovascular responses to AngII were 5.5 +/- 1.3 and 17.8 +/- 8.2 mmHg in untreated (n = 4) and sitagliptin-treated (n = 6) kidneys, respectively. Analysis of variance revealed a significant (P = 0.0367) effect of sitagliptin on renovascular responses to AngII that was independent of strain. 5. In conclusion, sitagliptin enhances renovascular responses to AngII in rats harbouring SHR genes and this effect persists in rats with diabetic nephropathy and metabolic syndrome.

Topics: Angiotensin II; Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Glycated Hemoglobin; Hypertension; Kidney; Male; Metabolic Syndrome; Proteinuria; Pyrazines; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renal Circulation; Sitagliptin Phosphate; Triazoles; Vasoconstriction; Vasoconstrictor Agents

The aim of the present study was to evaluate the effects of monotherapies and combinations of drugs on insulin sensitivity, adipose tissue morphology, and pancreatic and hepatic remodelling in C57BL/6 mice fed on a very HF (high-fat) diet. Male C57BL/6 mice were fed on an HF (60% lipids) diet or SC (standard chow; 10% lipids) diet for 10 weeks, after which time the following drug treatments began: HF-T (HF diet treated with telmisartan; 5.2 mg x kg-1 of body weight x day-1), HF-S (HF diet treated with sitagliptin; 1.08 g x kg-1 of body weight.day-1), HF-M (HF diet treated with metformin; 310.0 mg x kg-1 of body weight x day-1), HF-TM (HF diet treated with telmisartan+metformin), HF-TS (HF diet treated with telmisartan+sitagliptin) and HF-SM (HF diet treated with sitagliptin+metformin). Treated groups also had free access to the HF diet, and treatments lasted for 6 weeks. Morphometry, stereological tools, immunostaining, ELISA, Western blot analysis and electron microscopy were used. The HF diet yielded an overweight phenotype, an increase in oral glucose intolerance, hyperinsulinaemia, hypertrophied islets and adipocytes, stage 2 steatosis (>33%), and reduced liver PPAR-alpha (peroxisome-proliferator-activated receptor-alpha) and GLUT-2 (glucose transporter-2) levels, concomitant with enhanced SREBP-1 (sterol-regulatory-element-binding protein-1) expression (P<0.0001). Conversely, all drug treatments resulted in significant weight loss, a reversal of insulin resistance, islet and adipocyte hypertrophy, and alleviated hepatic steatosis. Only the HF-T and HF-TS groups had body weights similar to the SC group at the end of the experiment, and the latter treatment reversed hepatic steatosis. Increased PPAR-alpha immunostaining in parallel with higher GLUT-2 and reduced SREBP-1 expression may explain the favourable hepatic outcomes. Restoration of adipocyte size was consistent with higher adiponectin levels and lower TNF-alpha (tumour necrosis factor-alpha) levels (P<0.0001) in the drug-treated groups. In conclusion, all of the drug treatments were effective in controlling the metabolic syndrome. The best results were achieved using telmisartan and sitagliptin as monotherapies or as a dual treatment, combining partial PPAR-gamma agonism and PPAR-alpha activation in the liver with extended incretin action.

Topics: Adipocytes; Angiotensin II Type 1 Receptor Blockers; Animals; Benzimidazoles; Benzoates; Dietary Fats; Dipeptidyl-Peptidase IV Inhibitors; Drug Evaluation, Preclinical; Drug Therapy, Combination; Energy Intake; Glucose Tolerance Test; Hypoglycemic Agents; Insulin Resistance; Liver; Male; Metabolic Syndrome; Metformin; Mice; Mice, Inbred C57BL; Obesity; Pancreas; Pyrazines; Sitagliptin Phosphate; Telmisartan; Triazoles

Topics: Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Diabetes Mellitus, Type 2; Dipeptidyl Peptidase 4; Drug Therapy, Combination; Enalapril; Heart Rate; Hemodynamics; Humans; Metabolic Syndrome; Models, Biological; Peptidyl-Dipeptidase A; Pyrazines; Sitagliptin Phosphate; Triazoles