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The Dipeptidyl Peptidase-4 Inhibitor Des-Fluoro-Sitagliptin Regulates Brown Adipose Tissue Uncoupling Protein Levels in Mice with Diet-Induced Obesity  [PDF]
Takanobu Shimasaki, Takayuki Masaki, Kimihiko Mitsutomi, Daisuke Ueno, Koro Gotoh, Seiichi Chiba, Tetsuya Kakuma, Hironobu Yoshimatsu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063626
Abstract: Objective Dipeptidyl peptidase (DPP)-4 is responsible for the degradation of several peptides that contain an alanine or proline at the penultimate position or position P1. DPP-4 inhibitors (DPP-4is) have protective effects against type-2 diabetes and several metabolic disorders. Methods In the present study, we examined the effects of des-fluoro-sitagliptin (DFS), a DDP-4i, on body adiposity and levels of peroxisome proliferator-activated receptor (PPAR)-α, PPAR-γ coactivator-1 (PGC-1), and uncoupling proteins (UCPs) in mice with diet-induced obesity. Results Treatment with DFS dose-dependently decreased the weight of white adipose tissue and serum levels of glucose, compared with controls, without influencing food intake (P<0.05). Additionally, DFS treatment increased the levels of PPAR-α, PGC-1, and UCPs in brown adipose tissue (BAT), and of PPAR-α and UCP3 in skeletal muscle (P<0.05). Furthermore, the effects on BAT PGC-1 and muscle PPAR-α levels were attenuated by treatment with the glucagon-like peptide 1 (GLP-1) antagonist exendin (9–39). Interestingly, hypothalamic levels of proopiomelanocortin (POMC) were increased by DFS treatment and the effects of DFS on PPAR-α, PGC-1, and UCP levels were attenuated in melanocortin (MC)-4 receptor-deficient mice. Conclusions In conclusion, high-dose DFS appeared to regulate body adiposity and UCPs in mice with diet-induced obesity, at least partly through a GLP-1 and/or MC-4 pathway.
Nature of action of sitagliptin, the dipeptidyl peptidase-IV inhibitor in diabetic animals  [cached]
Davis Joseph,Singh Shuchita,Sethi Sachin,Roy Subhasis
Indian Journal of Pharmacology , 2010,
Abstract: Objective : The aim of this study was to evaluate the dipeptidyl peptidase-IV (DPP-IV) inhibitor sitagliptin with respect to mode of inhibition and its in vivo duration of inhibition and efficacy in type 2 diabetes animal model. Materials and Methods : DPP-IV enzyme assay was carried out in human plasma (10 μL) or human recombinant enzyme (10 ng) using H-Gly-Pro-AMC as a substrate. The competitive nature was estimated by plotting IC 50 values measured at different substrate concentrations on the Y axis and substrate concentration on the X axis. The tight binding nature was estimated by plotting IC 50 values measured at different plasma volumes on the Y axis and plasma volumes on the X axis. Fast binding kinetics was assessed by progressive curves at different inhibitor concentrations in the DPP-IV assay. The reversibility of the inhibitor was assessed by a dissociation study of the DPP-IV-sitagliptin complex. Durations of DPP-IV inhibition and efficacy were shown in ob/ob mice dosed at 10 mg/kg, p.o. Results : Sitagliptin is a competitive, reversible, fast and tight binding DPP-IV inhibitor. In ob/ob mice, 10 mg/kg, (p.o.) showed a long duration of inhibition of > 70% at 8 h. The duration was translated into long duration of efficacy (~ 35% glucose excursion at 8 h) in the same model and the effect was comparable to vildagliptin. Conclusion : The DPP-IV inhibitor sitagliptin behaves as a competitive, tight, and fast binding inhibitor. Sitagliptin differs mechanistically from vildagliptin and exhibits comparable efficacy to that of latter. The finding may give an understanding to develop-second generation DPP-IV inhibitors with desired kinetic profiles.
Effect of Sitagliptin "a Dipeptidyl Peptidase-4 (DPP-4) Inhibitor" on the Endocrine Part of the Pancreas in Experimentally induced Diabetes in Adult Albino Rat; A Light Microscopic and Biochemical Studies  [PDF]
Tamer M. M. Abu-Amara and Zeinab M.Gebaly
Egyptian Journal of Hospital Medicine , 2012,
Abstract: Sitagliptin is highly selective dipeptidyl peptidase-4 (DPP-4) inhibitor that is considered as one of the new oral therapies for management of type II diabetes. Because of the sitagliptin unknown effects on the endocrine part of the pancreas, especially on the cellular levels, this study was done to evaluate its effect on the endocrine part of the pancreas in experimentally-induced type II diabetic in adult albino rats. Material and Methods: The present study was carried out on 30 adult male albino rats which were divided into; Group I (untreated control group), Group II (diabetic group), where type II diabetes had been induced via alloxan intake) and group III (treated group), where 0.14 mg/100 mg B.W. sitagliptin was given orally per day for 3 weeks after induction of type-2 diabetes. The specimens were prepared for light microscopic examination. In parallel, the related biomedical parameters such as serum glucose and serum insulin levels had been estimated, statistically analyzed and compared between the three groups.Results: Sections of pancreas taken from diabetic rats showed morphological changes in islets of Langerhans cells in the form of pyknotic nuclei, cytoplasmic vacuolation, poor differentiation and abnormal shape and size of the cells. These morphological changes had been partially recovered in diabetic rats treated with sitagliptin. Also, the hyperglycemia and hypoinsulinemia that was detected in the control diabetic group had been nearly returned to normal after sitagliptin treatment.Conclusion: Sitagliptin drug has improved islet functions on both morphological and biomedical parameters in type II diabetic rats and can be taken into consideration as one of the new oral anti-diabetic drugs on the human level that need to be more investigated
Neonatal Exposure to the Dipeptidyl Peptidase-IV Inhibitors Diprotin A and Sitagliptin Induces Depression-Like Behavior, Anxiety, and Latent Aggression in Adolescent and Adult Rats  [PDF]
Nataliya A. Krupina, Nadezhda N. Khlebnikova
Journal of Behavioral and Brain Science (JBBS) , 2016, DOI: 10.4236/jbbs.2016.64018
Abstract: Emotional and motivational disorders in adults are often considered to be the result of altered neurodevelopment. Clinical and experimental data provide evidence that serine protease dipeptidyl peptidase-IV (DPP-IV, EC 3.4.14.5) is involved in the pathophysiology of psycho-emotional disorders. Recently, we have shown that adolescent and adult rats exhibit an increase in anxiety and depression-related behaviors after neonatal administration of a synthetic non-competitive inhibitor of DPP-IV, methionyl-2(S)-cyano-pyrrolidine. In the present study, we tested the effects of two competitive, selective DPP-IV inhibitors, sitagliptin (4 mg/kg) and diprotin A (2 mg/kg), administered at postnatal days 5 - 18 on the emotional and motivational behavior of adolescent and adult rats. We observed increased anxiety in one-month-old diprotin A- or sitagliptin-treated rats in the elevated plus maze; diprotin A also enhanced the animals’ anxiety score using a ranked scale for evaluating anxiety and phobias. In the sucrose consumption and preference test, depressive-like behavior was pronounced in both the diprotin A- and sitagliptin-treated one-month-old animals, while only the diprotin A-treated rats exhibited a decrease in sucrose consumption at the age of 2 months. The diprotin A-treated rats also demonstrated behavioral despair and decreased activity in the forced swimming test within 1 - 3 months of age. Increased aggression was observed in 1 - 3-month-old diprotin A-treated rats and in two-month-old sitagliptin-treated rats. These findings support the hypothesis that DPP-IV is involved in the genesis of emotional and motivational disorders. Additionally, the results show that diprotin А impairs the adolescent and adult rats’ behavior more significantly than sitagliptin when the animals were treated with the DPP-IV inhibitors in the early postnatal period.
Sitagliptin-induced hemolysis  [cached]
Bekur Ragini,Nagaraja M,Shivashankara K,Stanley Weena
Indian Journal of Pharmacology , 2010,
Abstract: Sitagliptin is a newer oral hypoglycemic drug of the dipeptidyl peptidase-IV inhibitor class. It appears to be a promising newer oral hypoglycemic agent. The advantages are the absence of hypoglycemia when used as monotherapy and they cause less gain weight. We report a case of sitagliptin-induced hemolysis, a rare side effect, not reported in the literature. As sitagliptin is widely used in type 2 diabetes mellitus physicians should be aware of the possibility of this rare but potentially serious adverse drug reaction.
Dipeptidyl Peptidase IV Inhibition Activates CREB and Improves Islet Vascularization through VEGF-A/VEGFR-2 Signaling Pathway  [PDF]
Balaji Samikannu, Chunguang Chen, Neelam Lingwal, Manju Padmasekar, Felix B. Engel, Thomas Linn
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082639
Abstract: Substitution of pancreatic islets is a potential therapy to treat diabetes and it depends on reconstitution of islet’s capillary network. In this study, we addressed the question whether stabilization of Glucagon-Like-Peptide-1 (GLP-1) by inhibiting Dipeptidyl Peptidase-IV (DPP-IV) increases β-cell mass by modulating vascularization. Mouse or porcine donor islets were implanted under kidney capsule of diabetic mice treated with DPP-IV inhibitor sitagliptin. Grafts were analyzed for insulin production, β-cell proliferation and vascularization. In addition, the effect of sitagliptin on sprouting and Vascular Endothelial Growth Factor (VEGF)-A expression was examined ex vivo. The cAMP response element-binding (CREB) and VEGF-A/ Vascular Endothelial Growth Factor Receptor (VEGFR)-2 signaling pathway leading to islet vascularization was explored. Sitagliptin increased mean insulin content of islet grafts and area of insulin-positive tissue as well as β-cell proliferation. Interestingly, sitagliptin treatment also markedly increased endothelial cell proliferation, microvessel density and blood flow. Finally, GLP-1 (7-36) stimulated sprouting and VEGF expression, which was significantly enhanced by sitagliptin- mediated inhibition of DPP-IV. Our in vivo data demonstrate that sitagliptin treatment phosphorylated CREB and induced islet vascularization through VEGF-A/VEGFR-2 signaling pathway. This study paves a new pathway for improvement of islet transplantation in treating diabetes mellitus.
Dipeptidyl Peptidase-4 Inhibitors and Inflammation: Dpp-4 Inhibitors Improve Mean Pleatelet Volume and Gamma Glutamyl Transferase Level  [PDF]
Deniz Avc?
Journal of Biosciences and Medicines (JBM) , 2019, DOI: 10.4236/jbm.2019.72004
Abstract: AIM: The purpose of this research was to determine the changes of the inflammatory parameters in the long term with the use of dipeptidyl peptidase-4 inhibitors. Material and Methods: In this research we have retrospectively reviewed the records of 80 patients who had added dipeptidyl peptidase-4 inhibitors (40 sitagliptin and 40 vildagliptin) to their ongoing therapies. Patients’ values of inflammation at the beginning of this process were taken as initial values, while values at the end of this process were considered as final values. Results: A total of 80 patients [38.8% (n = 31) of the patients were male, while 61.3% (n = 49) were female] enrolled in the study. When the whole group was evaluated, the mean age was 56.1 ± 9.7 years. The median follow-up time of the patients with DPP-4 inhibitors was 18 (2 - 64) months. The mean MPV value was measured as 8.79 ± 1.71 fL before DPP-4 inhibitors and it was 10.06 ± 1.42 fL after the follow-up period (p < 0.001). The median value serum GGT was 30.5 (13 - 194) U/L before DPP-4 inhibitor and 29.5 (12 - 112) U/L at the end (p = 0.048). The mean uric acid level before the use of di-peptidyl peptidase-4 inhibitors was 4.7 ± 1.6 mg/dL, and this level was 5.0 ± 1.5 mg/dL after the follow-up period (p = 0.048). Conclusion: In this study, it was observed that MPV and GGT levels were improved by dipeptidyl peptidase-4 inhibitors in long-term.
Emerging role of dipeptidyl peptidase-4 inhibitors in the management of type 2 diabetes  [cached]
Bernd Richter,Elizabeth Bandeira-Echtler,Karla Bergerhoff,Christian Lerch
Vascular Health and Risk Management , 2008,
Abstract: Bernd Richter, Elizabeth Bandeira-Echtler, Karla Bergerhoff, Christian LerchCochrane Metabolic and Endocrine Disorders Group, Department of General Practice, Heinrich-Heine University Duesseldorf, Duesseldorf, GermanyBackground: In type 2 diabetes mellitus (T2DM) there is a progressive loss of β-cell function. One new approach yielding promising results is the use of the orally active dipeptidyl peptidase-4 (DPP-4) inhibitors. However, every new compound for T2DM has to prove long-term safety especially on cardiovascular outcomes.Objectives: Systematic review and meta-analysis of the effects of sitagliptin and vildagliptin therapy on main efficacy parameters and safety.Selection criteria, data collection, and analysis: Randomized controlled clinical studies of at least 12 weeks’ duration in T2DM.Results: DPP-4 inhibitors versus placebo showed glycosylated hemoglobin A1c (A1c) improvements of 0.7% versus placebo but not compared to monotherapy with other hypoglycemic agents (0.3% in favor of controls). The overall risk profile of DPP-4 inhibitors was low, however a 34% relative risk increase (95% confidence interval 10% to 64%, P = 0.004) was noted for all-cause infection associated with sitagliptin use. No data on immune function, health-related quality of life and diabetic complications could be extracted.Conclusions: DPP-4 inhibitors have some theoretical advantages over existing therapies with oral antidiabetic compounds but should currently be restricted to individual patients. Long-term data on cardiovascular outcomes and safety are needed before widespread use of these new agents.Keywords: DPP-4 inhibitors, sitagliptin, vildagliptin, systematic review, meta-analysis
Diabetic Nephropathy Amelioration by a Low-Dose Sitagliptin in an Animal Model of Type 2 Diabetes (Zucker Diabetic Fatty Rat)  [PDF]
Cristina Mega,Edite Teixeira de Lemos,Helena Vala,Rosa Fernandes,Jorge Oliveira,Filipa Mascarenhas-Melo,Frederico Teixeira,Flávio Reis
Experimental Diabetes Research , 2011, DOI: 10.1155/2011/162092
Abstract: This study was performed to assess the effect of chronic low-dose sitagliptin, a dipeptidyl peptidase 4 inhibitor, on metabolic profile and on renal lesions aggravation in a rat model of type-2 diabetic nephropathy, the Zucker diabetic fatty (ZDF) rat. Diabetic and obese ZDF (fa/fa) rats and their controls ZDF (
Dipeptidyl peptidase-4 inhibitors in the management of type 2 diabetes: safety, tolerability, and efficacy  [cached]
Mary Elizabeth Cox,Jennifer Rowell,Leonor Corsino,et al
Drug, Healthcare and Patient Safety , 2010,
Abstract: Mary Elizabeth Cox1, Jennifer Rowell1, Leonor Corsino1, Jennifer B Green1,21Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition. Duke University Medical Center, Durham, NC, USA; 2Department of Medicine, Division of Endocrinology, Durham Veterans Affairs Medical Center, Durham, NC, USAAbstract: Although glycemic control is an important and effective way to prevent and minimize the worsening of diabetes-related complications, type 2 diabetes is a progressive disease which often proves difficult to manage. Most affected patients will eventually require therapy with multiple medications in order to reach appropriate glycemic targets. The dipeptidyl peptidase-4 (DPP-4) inhibitors constitute a relatively new class of oral medications for the treatment of type 2 diabetes, which has become widely incorporated into clinical practice. This review summarizes the available data on the efficacy, safety, and tolerability of these medications.Keywords: type 2 diabetes, pharmacotherapy, DPP-4 inhibitor, sitagliptin, vildagliptin, saxagliptin, alogliptin, linagliptin
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