sitagliptin-phosphate and Diabetic-Nephropathies

Diabetic nephropathy (DN) is now the single commonest cause of end-stage renal disease (ESRD) worldwide and one of the main causes of death in diabetic patients. It is also acknowledged as an independent risk factor for cardiovascular disease (CVD). Since sitagliptin was approved, many studies have been carried out revealing its ability to not only improve metabolic control but also ameliorate dysfunction in various diabetes-targeted organs, especially the kidney, due to putative underlying cytoprotective properties, namely, its antiapoptotic, antioxidant, anti-inflammatory, and antifibrotic properties. Despite overall recommendations, many patients spend a long time well outside the recommended glycaemic range and, therefore, have an increased risk for developing micro- and macrovascular complications. Currently, it is becoming clearer that type 2 diabetes mellitus (T2DM) management must envision not only the improvement in glycaemic control but also, and particularly, the prevention of pancreatic deterioration and the evolution of complications, such as DN. This review aims to provide an overview of the current knowledge in the field of renoprotective actions of sitagliptin, namely, improvement in diabetic dysmetabolism, hemodynamic factors, renal function, diabetic kidney lesions, and cytoprotective properties.

Topics: Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Humans; Protective Agents; Sitagliptin Phosphate; Treatment Outcome

Chronic kidney disease (CKD) is a common complication of diabetes mellitus and the most common cause of end-stage renal disease (ESRD). As the worldwide prevalence of diabetes continues to increase, the number of patients with CKD will also increase. Therefore, it is essential that physicians know how to safely and effectively manage diabetes in the setting of CKD. Adequate glycaemic control in patients with diabetes is important to prevent ESRD and other complications and to decrease mortality. However, many glucose-lowering agents need to be dose-adjusted or should not be used in the setting of stage 3 CKD or higher (defined as an estimated glomerular filtration rate [eGFR] <60 ml/min/1.73 m(2)), particularly in patients with stage 5 CKD (eGFR <15 ml/min/1.73 m(2)) and in those receiving dialysis. Insulin therapy is appropriate for patients undergoing dialysis; however, several orally administered glucose-lowering agents can also be used safely in these patients. In this Review, we provide an overview of the use of noninsulin glucose-lowering agents in the dialysis population.

Topics: Adamantane; Biguanides; Diabetic Nephropathies; Dipeptides; Dipeptidyl-Peptidase IV Inhibitors; Disease Progression; Glucagon-Like Peptides; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Linagliptin; Meglumine; Metformin; Nitriles; Piperidines; Purines; Pyrazines; Pyrrolidines; Quinazolines; Renal Dialysis; Renal Insufficiency, Chronic; Sitagliptin Phosphate; Sulfonylurea Compounds; Thiazolidinediones; Treatment Outcome; Triazoles; Uracil; Vildagliptin

To characterize the incidence of diabetes-associated complications and assess the safety of sitagliptin in participants with chronic kidney disease (CKD) in the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS).. For participants with baseline eGFR measurements (n = 14 528), baseline characteristics and safety outcomes were compared for the CKD cohort (eGFR < 60 mL/min per 1.73 m. CKD was present in 3324 (23%) participants at entry into TECOS. The mean (SD) age for this CKD cohort was 68.8 (7.9) years, mean diabetes duration was 13.7 (9.0) years, and 62% were men. Incidences of serious adverse events, malignancy, bone fracture, severe hypoglycaemia and most categories of diabetes complications were higher in the CKD cohort compared with those without CKD. Over ~2.8 median years of follow-up, CKD participants assigned to sitagliptin had rates of diabetic eye disease, diabetic neuropathy, renal failure, malignancy, bone fracture, pancreatitis and severe hypoglycaemia similar to those of placebo-assigned participants.. Participants in TECOS with CKD had higher incidences of serious adverse events and diabetes complications than those without CKD. Treatment with sitagliptin was generally well tolerated, with no meaningful differences in safety outcomes observed between those with CKD assigned to sitagliptin or placebo.

Topics: Aged; Cohort Studies; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Drug-Related Side Effects and Adverse Reactions; Female; Glomerular Filtration Rate; Humans; Male; Middle Aged; Placebos; Renal Insufficiency, Chronic; Sitagliptin Phosphate; Treatment Outcome

Dipeptidyl peptidase-4 (DPP-4) inhibitor is a new class of anti-diabetic drug which exerts its glucose-lowering action by suppressing the degradation of a gut incretin hormone glucagon-like peptide-1 (GLP-1). To elucidate whether treatment with stronger DPP-4 inhibitor on top of angiotensin II type 1 receptor blocker (ARB) provides greater renal protective effects, we performed a crossover study with two DPP-4 inhibitors, sitagliptin and alogliptin, in twelve type 2 diabetic patients with incipient nephropathy taking ARBs. This study consisted of three treatment periods: sitagliptin 50 mg/day for 4 weeks (first period), alogliptin 25 mg/day for 4 weeks (second period), and sitagliptin 50 mg/day for 4 weeks (third period). Significant changes in body mass index, blood pressure, serum lipids, serum creatinine, estimated glomerular filtration rate, and HbA1c were not observed among the three treatment periods. Reduced urinary levels of albumin and an oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG), increased urinary cAMP levels, and elevated plasma levels of stromal cell-derived factor-1α (SDF-1α) which is a physiological substrate of DPP-4 were observed after the switch from sitagliptin to a stronger DPP-4 inhibitor alogliptin. Given a large body of evidence indicating anti-oxidative action of cAMP and up-regulation of cellular cAMP production by SDF-1α, the present results suggest that more powerful DPP-4 inhibition on top of angiotensin II type 1 receptor blockade would offer additional protection against early-stage diabetic nephropathy beyond that attributed to glycemic control, via reduction of renal oxidative stress by SDF-1α-cAMP pathway activation.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Albuminuria; Angiotensin II Type 1 Receptor Blockers; Chemokine CXCL12; Cross-Over Studies; Cyclic AMP; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Female; Humans; Male; Middle Aged; Piperidines; Pyrazines; Receptor, Angiotensin, Type 1; Sitagliptin Phosphate; Triazoles; Up-Regulation; Uracil

To evaluate weekly subcutaneous albiglutide versus daily sitagliptin in renally impaired patients with type 2 diabetes and inadequately controlled glycemia on a regimen of diet and exercise and/or oral antihyperglycemic medications.. In this phase III, randomized, double-blind, multicenter, 52-week study, the primary study end point was HbA1c change from baseline at week 26 in patients with renal impairment, as assessed with estimated glomerular filtration rate and categorized as mild, moderate, or severe (≥60 to ≤89, ≥30 to ≤59, and ≥15 to ≤29 mL/min/1.73 m(2), respectively). Secondary end points included fasting plasma glucose (FPG), weight, achievement of treatment targets, hyperglycemic rescue, and safety.. Baseline demographics were similar across treatment and renal impairment groups with overall mean age of 63.3 years, BMI of 30.4 kg/m(2), HbA1c of 8.2% (66 mmol/mol), and diabetes disease duration of 11.2 years. HbA1c change from baseline at week 26 was significantly greater for albiglutide than sitagliptin (-0.83% vs. -0.52%, P = 0.0003). Decreases in HbA1c, FPG, and weight were seen through week 52. Time to hyperglycemic rescue through week 52 was significantly longer for albiglutide than sitagliptin (P = 0.0017). Results of safety assessments were similar between groups, and most adverse events (AEs) were mild or moderate. The incidences of gastrointestinal AEs for albiglutide and sitagliptin were as follows: overall, 31.7%, 25.2%; diarrhea, 10.0%, 6.5%; nausea, 4.8%, 3.3%; and vomiting, 1.6%, 1.2%, respectively.. Once-weekly albiglutide therapy in renally impaired patients with type 2 diabetes provided statistically superior glycemic improvement with almost similar tolerability compared with daily sitagliptin therapy.

Topics: Aged; Blood Glucose; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Double-Blind Method; Drug Administration Schedule; Female; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Pyrazines; Receptors, Glucagon; Renal Insufficiency; Sitagliptin Phosphate; Treatment Outcome; Triazoles

This randomized, prospective study was conducted in 76 subjects to assess whether low-dose (0.5-2 mg/day) glimepiride, in combination therapy with sitagliptin, improves glycemic control in a dose-dependent manner in Japanese patients with type 2 diabetes. Eligible subjects had been treated with glimepiride at doses of 3-6 mg/day for at least 3 months and had a HbA1c level of ≥6.9%. Subjects were randomly assigned to three treatment groups of reduced doses of glimepiride (0.5 mg/day, 1 mg/day, or 2 mg/day) in addition to sitagliptin for 24 weeks. The primary efficacy analysis evaluated the change in HbA1c from baseline to week 24. Secondary efficacy endpoints included the changes in fasting plasma glucose, insulin secretion capacity, and β-cell function. Safety endpoints included hypoglycemia and any adverse event. Despite dose reduction of glimepiride, combination therapy with sitagliptin induced significant improvements in HbA1c levels (-0.8%, p < 0.001). Insulin secretion parameters (CPI, SUIT) also increased significantly. There were no significant differences between groups in changes from baseline HbA1c, insulin secretion capacity, and β-cell function (proinsulin/insulin) at 24 weeks of combination therapy. Multivariate analysis showed that baseline HbA1c was the only predictor for efficacy of combination therapy with sitagliptin and low-dose glimeripide. No changes in body weight were noted and no symptomatic hypoglycemia was documented. These findings indicate that combination therapy with sitagliptin and low-dose glimepiride (0.5 mg/day) is both effective for glycemic control and safe in Japanese patients with type 2 diabetes inadequately controlled with high-dose glimepiride.

Topics: Aged; Cohort Studies; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Dose-Response Relationship, Drug; Drug Resistance; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hyperglycemia; Incretins; Insulin; Insulin Secretion; Insulin-Secreting Cells; Japan; Kidney; Male; Middle Aged; Pyrazines; Severity of Illness Index; Sitagliptin Phosphate; Sulfonylurea Compounds; Triazoles

Treatment with oral antihyperglycemic agents has not been well characterized in patients with type 2 diabetes and end-stage renal disease (ESRD). The efficacy and safety of sitagliptin and glipizide monotherapy in patients with type 2 diabetes and ESRD on dialysis therapy were assessed in this study.. 54-week, randomized, double-blind, parallel-arm study.. From 31 clinical sites in 12 countries, 129 patients 30 years or older with type 2 diabetes and ESRD who were on dialysis therapy and had a hemoglobin A1c (HbA1c) level of 7%-9% were randomly assigned 1:1 to treatment.. Monotherapy with sitagliptin, 25 mg daily or glipizide (initiated with 2.5 mg daily and titrated up to a potential maximum dose of 10 mg twice daily or down to avoid hypoglycemia).. Primary end points were 54-week change in HbA1c level from baseline and tolerability with sitagliptin. A secondary end point was the comparison of sitagliptin versus glipizide on the incidence of symptomatic hypoglycemia.. Of 129 patients randomly assigned, 64 were in the sitagliptin group (mean baseline age, 61 years; HbA1c, 7.9%) and 65 were in the glipizide group (mean baseline age, 59 years; HbA1c, 7.8%). After 54 weeks, the least squares mean change from baseline in HbA1c level was -0.72% (95% CI, -0.95% to -0.48%) with sitagliptin and -0.87% (95% CI, -1.11% to -0.63%) with glipizide, for a difference of 0.15% (95% CI, -0.18% to 0.49%). The incidences of symptomatic hypoglycemia and severe hypoglycemia were 6.3% versus 10.8% (between-group difference, -4.8% [95% CI, -15.7% to 5.6%]) and 0% versus 7.7% (between-group difference, -7.8% [95% CI, -17.1% to -1.9%]) in the sitagliptin and glipizide groups, respectively. Higher incidences (ie, 95% CI around between-treatment difference excluded 0) of cellulitis and headache were found with sitagliptin compared to glipizide (6.3% vs 0%, respectively, for both).. Small sample size limits between-group comparisons.. Treatment with sitagliptin or glipizide monotherapy was effective and well tolerated over 54 weeks in patients with type 2 diabetes and ESRD who were receiving dialysis.

Topics: Blood Glucose; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Double-Blind Method; Glycated Hemoglobin; Humans; Kidney Failure, Chronic; Pyrazines; Renal Dialysis; Sitagliptin Phosphate; Triazoles

Topics: Adult; Aged; Asia; Asian People; Biomarkers; Body Mass Index; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Female; Glycated Hemoglobin; Humans; Male; Middle Aged; Pyrazines; Sitagliptin Phosphate; Treatment Outcome; Triazoles

Diabetic nephropathy is the leading cause of end-stage renal failure, but the effectiveness of currently available strategies for preventing diabetic nephropathy remains unsatisfactory. This study was designed to evaluate the changes in adipokines levels caused by dipeptidyl peptidase-4 inhibitor sitagliptin therapy as one of the possible mechanisms of sitagliptin's amelioration of diabetic nephropathy. Twenty-four male Wistar rats weighing 180-200 g were taken and divided into three groups, that is, control, diseased, and treatment group. High-fat diet and streptozotocin-induced Type 2 diabetic rats were divided into diseased and treatment groups. The treatment group was given sitagliptin orally, 10 mg/kg per day for 6 weeks. Serum glucose, serum insulin, serum blood urea nitrogen, serum creatinine, and 24-h urinary protein levels were measured in serum and urine samples. mRNA expression levels of podocin, nephrin, and adipokines in renal tissues were determined. Results showed that sitagliptin treatment effectively reduced serum glucose, serum creatinine, serum blood urea nitrogen, and 24-h proteinuria, along with partial prevention of insulinopenia, in the treatment group as compared to the diseased group. The renal mRNA expression levels of podocin, nephrin, and adiponectin were significantly upregulated, while those of leptin and resistin were significantly downregulated in the diabetic rats receiving sitagliptin therapy compared to the non-treated diabetic rats. Based on these findings, it is suggested that sitagliptin, via mediating the modulation of adipokines levels, upregulates renal nephrin and podocin expression, which leads to the amelioration of diabetic nephropathy.

Topics: Adipokines; Animals; Creatinine; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Glucose; Male; Rats; Rats, Wistar; RNA, Messenger; Sitagliptin Phosphate

Management of diabetic nephropathy (DN) is far from satisfactory. There is a rising role of the involvement of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway in the pathogenesis of DN. This study aimed at investigating the renoprotective effects of PI3K/AKT pathway via sitagliptin in a rat model of DN. Thirty-two male Wistar rats were divided into four groups (eight rats each): (I) control, (II) sitagliptin, (III) DN, and (IV) DN + sitagliptin. Fasting blood glucose (FBG), kidney index, and kidney function tests in both blood and urine were measured. The levels of superoxide dismutase (SOD), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta (TGF-β) and gene expressions of PI3K, pPI3K, AKT, and pAKT in renal tissue were detected. Renal histopathological and immunohistochemical studies were evaluated. DN + sitagliptin group showed significant decrease in FBG and kidney index, improvement in kidney function tests, and a decrease in levels of TNF-α and TGF-β in renal tissues compared with DN group. This was associated with significant increase in SOD and gene expressions of PI3K and AKT and their phosphorylated active forms in renal tissue in DN + sitagliptin group compared with DN group. Moreover, DN + sitagliptin group showed apparent decrease in amount of collagen fibers and expression of alpha-smooth muscle actin (α-SMA) compared with DN group. This work shows that sitagliptin improved renal functions and histopathological changes, impeded inflammation, and oxidative stress and upregulated PI3K/AKT pathway which highlights its renoprotective effects in a rat model of DN.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Kidney; Male; Phosphatidylinositol 3-Kinase; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Sitagliptin Phosphate

Sitagliptin is a well-established anti-diabetic drug that also exerts protective effects on diabetic complications. Previous work reveals that sitagliptin has a protective effect on diabetic nephropathy (DN). Vascular impairment frequently occurs in diabetic renal complications. Here, we evaluated the protective function of sitagliptin in human renal glomerular endothelial cells (HrGECs) under high glucose (HG) conditions. Expressions of the pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-8 (IL-8) were assessed using real-time PCR and ELISA. Endothelial cells permeability was assayed using the fluorescein isothiocyanate dextran (FITC-dextran) and trans-endothelial electrical resistance (TEER) assay. The results show that sitagliptin mitigated HG-induced oxidative stress in HrGECs with decreased levels of mitochondrial reactive oxygen species (ROS), Malondialdehyde (MDA), and 8-hydroxydeoxyguanosine (8-OHdG). Sitagliptin inhibited HG-induced production of pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-8 (IL-8) in HrGECs. It also ameliorated HG-induced aggravation of HrGECs permeability and reduction of the tight junction component claudin-5. Moreover, kruppel Like Factor 6 (KLF6) mediated the protective effects of sitagliptin on endothelial monolayer permeability against HG. Collectively, sitagliptin reversed the HG-induced oxidative stress, inflammation, and increased permeability in HrGECs via regulating KLF6. This study suggests that sitagliptin might be implicated as an effective strategy for preventing diabetic renal injuries in the future.

Topics: Cell Line; Diabetic Nephropathies; Endothelial Cells; Glucose; Humans; Inflammation; Kidney Glomerulus; Oxidative Stress; Sitagliptin Phosphate

Topics: Animals; Collagen; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Extracellular Matrix Proteins; Fibrosis; Hypoglycemic Agents; Kidney; MAP Kinase Signaling System; Oxidative Stress; Rats; Signal Transduction; Sitagliptin Phosphate

Mitochondrial abnormalities play critical roles in diabetic tubular injury progression. Dipeptidyl peptidase-4 (DPP4) inhibitors are widely used antihyperglycemic agents that exert renal protective and positive effects against mitochondrial dysfunction in diabetic kidney disease (DKD). However, their underlying mechanism remains unclear. In this study, DPP4 upregulation, mitochondrial fragmentation, and altered mitochondrial dynamics-associated protein expression were observed in the tubules of DBA2/J (D2) diabetic mice with unilateral nephrectomy and in albumin-stimulated tubular cells. The inhibition of DPP4 by sitagliptin (Sita) ameliorated these mitochondrial perturbations both in vivo and in vitro, whereas DPP4 overexpression aggravated mitochondrial fusion-fission disorder and tubular cell injury in albumin-treated HK-2 cells. Downstream of DPP4, the SDF-1α/CXCR4 pathway was significantly suppressed in diabetic tubules. After Sita treatment, this signaling pathway was restored, and the mitochondrial dynamics was improved. Furthermore, a direct interaction between STAT3 and OPA1 was found in the mitochondria of tubular cells, and this effect was weakened by overloading albumin and by CXCR4 siRNA treatment, suggesting a possible link between DPP4-mediated SDF-1α/CXCR4/STAT3 signaling and mitochondrial dysfunction in diabetic tubular cells. The results suggest that a novel mechanism links the DPP4 enzyme to impaired mitochondrial dynamics homeostasis during tubular injury in DKD and highlight that the SDF-1α/CXCR4/STAT3 signaling pathway could become a potential target for managing DKD.

Topics: Animals; Cell Line; Chemokine CXCL12; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidase IV Inhibitors; Homeostasis; Humans; Kidney; Kidney Tubules; Male; Mice; Mice, Inbred DBA; Mitochondria; Receptors, CXCR4; Signal Transduction; Sitagliptin Phosphate; STAT3 Transcription Factor

Oxidative stress has been linked to the development and progression of diabetic nephropathy (DN). The present study evaluated whether the dipeptidyl peptidase-4 inhibitor sitagliptin attenuates glomerular lesions and oxidative stress evoked by chronic hyperglycemia, by a mechanism independent of insulin secretion and glycemia normalization.. A rat model of DN caused by streptozotocin injection was established and the effects of sitagliptin (5 mg/kg/day) were evaluated after two weeks of treatment.. Sitagliptin treatment did not change body weight, glycemic and lipid profiles. However, histopathological observation revealed that sitagliptin attenuates diabetes-induced glomerular lesions on diabetic rats. Sitagliptin also ameliorated the increase in DPP-4 content and promoted the stabilization of GLP-1 in the diabetic kidney. Furthermore, sitagliptin treatment significantly attenuated the increase of free-radical formation and the decrease of antioxidant defenses, attenuating therefore the oxidative stress in the kidneys of diabetic animals.. The results suggest that sitagliptin treatment alleviates kidney oxidative stress in type 1 diabetic rats, which could play a key role in reducing the progression of DN.

Topics: Animals; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Kidney Glomerulus; Male; Oxidative Stress; Rats; Rats, Wistar; Sitagliptin Phosphate

To investigate the effect of sitagliptin on Wnt/β-catenin signalling in the tubulointerstitium of diabetic nephropathy.. Forty male Wistar rats were divided into normal control (NC), diabetic model (DM), low and high-dose sitagliptin intervention groups (ST1 and ST2, respectively). Changes in the biochemical parameters and tubulointerstitial fibrosis index were observed. The levels of protein and gene expression of different indicators were detected via immunohistochemistry and real-time polymerase chain reaction. NRK-52E cells were divided into the normal control group, mannitol control group, high glucose group (HG), high glucose plus sitagliptin intervention group (HG + ST) and high glucose plus Wnt/β-catenin inhibitor group (HG + XAV939). The relevant indicators were examined by Western blot or enzyme-linked immunosorbent assay.. Compared with the NC group, the blood glucose, glycosylated haemoglobin, 24 h urinary albumin, creatinine clearance and tubulointerstitial fibrosis index were significantly increased in the DM group. These parameters were decreased in the ST1 and ST2 groups compared to the DM group. Compared with the NC group, the levels of Wnt4, β-catenin, dipeptidyl peptidase-4 and α-smooth muscle actin were higher and E-cadherin was lower in the DM group. Sitagliptin treatment reversed these changes. In the high glucose-stimulated NRK-52E cells, sitagliptin and XAV939 inhibited the elevated expression of Wnt4, β-catenin, dipeptidyl peptidase-4, α-smooth muscle actin, transforming growth factor-β and fibronectin and restored E-cadherin activity.. Sitagliptin may inhibit the tubulointerstitial Wnt/β-catenin signalling pathway in diabetic nephropathy and provide renal protection by alleviatinge renal tubulointerstitial transdifferentiation and fibrosis.

Topics: Actins; Animals; Cells, Cultured; Diabetic Nephropathies; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidase IV Inhibitors; Kidney; Male; Rats; Rats, Wistar; Sitagliptin Phosphate; Transforming Growth Factor beta; Wnt Signaling Pathway; Wnt4 Protein

Oxidative stress is an important mechanism for diabetic nephropathy. Studies showed that hemo oxygenase-1 (HO-1) expression in renal tissue of patients with diabetic nephropathy has upregulated, while the HO-1 can protect the body through anti-oxidative stress. The study aimed to preliminarily explore the molecular mechanism by observing the effect of Sitagliptin on HO-1 expression in renal tissue of rats with diabetic nephropathy.. The diabetic nephropathy rat model was established by STZ injection followed by intraperitoneal injection of sitagliptin with different concentrations. The mRNA expressions of HO-1 were detected by real-time PCR and Western blot and HO-1 enzyme activity change was detected by colorimetry. Human renal mesangial cell (HRMC) were cultured in vitro with high glucose concentration (30 μmol/L), phosphatidylinositol-3-kinase (PI3K) level and nuclear factor erythroid-2-related factor (Nrf2) content in cytoplasm and cell nucleus were observed before and after treatment with sitagliptin, as well as the action of in meditating HO-1 expression.. HO-1 mRNA, protein level, and HO-1 enzyme activity in renal tissue of rats with diabetic nephropathy were significantly increased after treatment with sitagliptin (P < 0.05). As comparison, the 24 h urinary microalbumin, creatinine, and boold urea nitrogen were all decreased after treatment of sitagliptin (P < 0.05). Similar results were observed after CoPP (an agonist of HO-1) treatment (P < 0.05). In contrast, ZnPP, an inhibitor of HO-1, significantly abrogated the inhibitory effect of sitagliptin (P < 0.05). Phosphorylation of PI3K and Nrf2 nuclear translocation under high-glucose concentration condition was induced by sitagliptin in HRMC. HO-1 expression was suppressed by pretreating HRMC with PI3K inhibitor or RNA interference.. Sitagliptin may induce HO-1 expression via activation of PI3K and Nrf2 in rats with diabetic nephropathy; HO-1 can improve the oxidative stress of diabetic nephropathy, eventually protect from diabetic nephropathy.

Topics: Animals; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Glomerular Mesangium; Glucose; Heme Oxygenase (Decyclizing); Humans; Hypoglycemic Agents; Kidney; Kidney Function Tests; Male; NF-E2-Related Factor 2; Phosphatidylinositol 3-Kinases; Rats; Rats, Sprague-Dawley; Sitagliptin Phosphate; Up-Regulation

Type 2 Diabetes Mellitus (T2DM) is a world-wide metabolic disease with no cure from drugs and treatment. In China, The Traditional Chinese Medicine (TCM) herbal formulations have been used to treat T2DM for centuries.. In this study, we proposed a formula called ShenQi Compound (SQC), which has been used in clinical therapeutics in China for several years. We evaluated the effect of SQC in a spontaneous diabetic rat model (GK rats) by detecting a series of blood indicators and performing histological observations. Meanwhile, the gene microarray and RT-qPCR experiments were used to explore the molecular mechanism of SQC treatment. In addition, western medicine, sitagliptin was employed as a comparison.. The results indicated that SQC and sitagliptin could effectively improve the serum lipid (blood Total Cholesterol (TC) and blood Triglycerides (TG)), hormone levels (serum insulin (INS), Glucagon (GC) and Glucagon-Like Peptide-1 (GLP-1)), alleviated the inflammatory response (hypersensitive C-Reactive Protein (hsCRP)), blood glucose fluctuation (Mean Blood Glucose (MBG), standard deviation of blood glucose (SDBG) and Largest Amplitude of plasma Glucose Excursions (LAGE)), pancreatic tissue damage and vascular injury for T2DM. Compared with sitagliptin, SQC achieved a better effect on blood glucose fluctuation (p<0.01). Meanwhile, the gene microarray and RT-qPCR experiments indicated that SQC and sitagliptin may improve the T2DM through affecting the biological functions related to apoptosis and circadian rhythm. Moreover, SQC might be able to influence the mTOR signaling pathway by regulating Pik3r1, Ddit4 expression.. All these results indicate that SQC is an effective therapeutic drug on T2DM. Notably, SQC presents an obvious blood glucose fluctuation-preventing ability, which might be derived from the regulation of the mTOR signaling pathway.

Topics: Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Drugs, Chinese Herbal; Gene Expression Profiling; Male; Medicine, Chinese Traditional; Microarray Analysis; Rats; Rats, Wistar; Sitagliptin Phosphate

Studies indicated that imbalance of proinflammatory and anti-inflammatory cytokines may contribute to development of type 2 diabetes mellitus (T2DM). We hypothesized that sitagliptin and VitD3 may exert more anti-inflammatory effects on the regulation of cytokine balance in T2DM. Nonnephropathic and nephropathic T2DM patients were divided into the subgroups, based on treatments. The effect of 8 months sitagliptin, alone or together with 2 months of VitD3, on serum IFN-γ, IL-4, IL-17, IL-6, IL-21, TGF-β, and IL-37 levels was determined using enzyme-linked immunosorbent assay. Increased levels of interferon (IFN)-γ and IL-17 in untreated (without sitagliptin and VitD3) nephropathic and nonnephropathic patients and decreased levels of IL-37 in untreated nephropathic patients were observed compared with healthy controls. Treatment with sitagliptin plus VitD3 reduced the levels of IFN-γ and IL-17 in both nonnephropathic and nephropathic patients compared with untreated patients. The level of IL-37 was enhanced in patients treated with sitagliptin or sitagliptin plus VitD3, compared with untreated patients. Sitagliptin plus VitD3 treatment increased the levels of IL-4 in nonnephropathic patients. These findings indicated that the sitagliptin plus VitD3 was more effective to reduce the increased proinflammatory IFN-γ and IL-17 cytokines in T2DM patients.

Topics: Adult; Anti-Inflammatory Agents; Cholecalciferol; Cytokines; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Drug Combinations; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Sitagliptin Phosphate; Young Adult

Diabetic nephropathy (DN) is a common cause of end-stage kidney disease (ESKD) all over the world. Sitagliptin, an inhibitor of DPP-IV plays a beneficial role in type 2 diabetic nephropathy. The purpose of this study was to explore the effect and mechanism of sitagliptin on renal injury in type 1 diabetic mice. Streptozotocin (STZ) induced type 1 diabetic mice were treated with oral administration of sitagliptin (15 mg/kg/ day) for 4 weeks. The results showed that sitagliptin treatment did not change the levels of blood glucose in STZ induced type 1 diabetic mice. Sitagliptin attenuates diabetic nephropathy by significantly inhibiting 24 h proteinuria, renal injury and fibrosis. Sitagliptin can inhibit the expression level of TGF-β1 and the other related fibrosis factors in renal tissue of type 1 diabetic mice while delaying the progression of type 1 diabetic nephropathy. These results indicated that sitagliptin treatment is potentially a new strategy for treating type 1 diabetic nephropathy.

Topics: Administration, Oral; Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Hypoglycemic Agents; Male; Mice; Proteinuria; Signal Transduction; Sitagliptin Phosphate; Smad Proteins; Streptozocin; Transforming Growth Factor beta1

Diabetic nephropathy (DN) is the leading cause of end-stage failure of the kidney, but the efficacy of current strategies available for the prevention of DN remains unsatisfactory. The purpose of this study was to assess whether sitagliptin (SIT) has therapeutic potential for prevention of DN and to investigate its possible mechanism. The effects of SIT on DN were investigated in rats with type 2 diabetes mellitus (T2DM) and rat mesangial cells (MCs) induced by high glucose. T2DM rats were administered at a dose of 10 mg/kg SIT. The kidney index, 24 h urinary protein, blood urea nitrogen (BUN), serum creatinine (Cr), accumulation of glycogen and collagens were investigated by different methods. MCs were administered with SIT at doses of 0.1, 1 and 10 µmol/ml. The possible mechanism of SIT on protection of diabetic kidney injury was examined by expression of transforming growth factor-β1 (TGF-β1)/Smad pathway. The results showed that the SIT-treated diabetic rats significantly reduced diabetic kidney injury by inhibiting the kidney index and attenuating 24 h urinary protein, reducing BUN and serum creatinine, inhibiting progressive renal fibrosis and increassing extracellular matrix including collagen IV and fibronectin. Further studies showed that inhibition of renal fibrosis in SIT-treated diabetic rats and MCs were associated with rebalancing of TGF-β1/Smad pathway. Sitagliptin may be a potent agent for preventing the progression of DN through inhabiting TGF-β1/Smad-mediated renal fibrosis.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Fibrosis; Hypoglycemic Agents; Kidney; Male; Mesangial Cells; Rats; Rats, Sprague-Dawley; Signal Transduction; Sitagliptin Phosphate; Smad Proteins; Transforming Growth Factor beta1

Diabetic nephropathy (DN) has become the major complication of diabetes. The progression of the disease impedes the efficacy of DN treatment. Therefore, the strategies to inhibit or reverse kidney damage in DN patients are of critical importance. We aim to investigate the effect of sitagliptin on DN within rat model and analyze the associated metabolism and expression of iNOS/GLP-1 receptor.. Diabetic model was generated by using Sprague-Dawley (SD) rats, which received an intra-peritoneal injection of 30 mg/kg streptozotocin. Rats were then treated with saline or 15 mg/(kg.d) sitagliptin by gavage. After 12 weeks, fasting blood glucose and insulin resistance were measured. Rat glucose and lipid metabolism were evaluated by high triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). Western blot was used to measure expression of glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK), fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) related with glucose-lipid metabolism, and expression of iNOS and GLP-1 expression in kidney tissues.. After 12 weeks of feeding, the levels of blood glucose and lipid in sitagliptin group were significantly decreased compared to those in control group (p<0.05), whilst insulin sensitivity was enhanced (p<0.05). Western blot showed that sitagliptin downregulated the expressions of glucose-lipid metabolism proteins such as G6Pase, PEPCK, ACC and FAS in rat livers, inhibited iNOS expression in kidneys and elevated GLP-1 receptor activity (p<0.05).. Sitagliptin effectively stabilizes blood glucose and lipid levels in DN rats, significantly improves glucose-lipid metabolism and protects kidney and vascular endothelial cells during DN pathogenesis through inhibiting iNOS expression and elevating GLP-1 receptor activity.

Topics: Animals; Biomarkers; Blood Glucose; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Energy Metabolism; Glucagon-Like Peptide-1 Receptor; Kidney; Lipids; Liver; Male; Nitric Oxide Synthase Type II; Rats, Sprague-Dawley; Sitagliptin Phosphate

Limited data are available about the cardiovascular (CV) safety and efficacy of sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, in ischemic stroke patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD). Ischemic stroke patients with T2DM and CKD were selected from the Taiwan National Health Insurance Research Database (NHIRD) from March 1, 2009 to December 31, 2011. A total of 1375 patients were divided into 2 age- and gender-matched groups: patients who received sitagliptin (n = 275; 20%) and those who did not (n = 1,100). Primary major adverse cardiac and cerebrovascular events (MACCE), including ischemic stroke, hemorrhagic stroke, myocardial infarction (MI), or CV death, were evaluated. During a mean 1.07-year follow-up period, 45 patients (16.4%) in the sitagliptin group and 165 patients (15.0%) in the comparison group developed MACCEs (Hazard ratio [HR] 1.05; 95% confidence interval [CI], 0.75-1.45). Compared to the non-sitagliptin group, the sitagliptin group had a similar risk of ischemic stroke (HR 0.82; 95% CI, 0.51-1.32.), hemorrhagic stroke (HR 1.50; 95% CI, 0.58-3.82), MI (HR 1.14; 95% CI, 0.49-2.65), and CV mortality (HR 1.06; 95% CI, 0.61-1.85). The use of sitagliptin in recent ischemic stroke patients with T2DM and CKD was not associated with increased or decreased risk of adverse CV events.

Topics: Aged; Cardiovascular Diseases; Cohort Studies; Databases, Factual; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Female; Humans; Hypoglycemic Agents; Male; Middle Aged; Renal Insufficiency, Chronic; Risk Factors; Sitagliptin Phosphate; Stroke; Taiwan

The protective effects of sitagliptin on the kidneys of rats with diabetic nephropathy (DN) and its influence on extracellular signal-regulated kinases 1/2 (ERK1/2) signaling were investigated. Male Wistar rats (n = 40) were randomly assigned to normal control, DN, low-dose sitagliptin intervention (ST1), or high-dose sitagliptin intervention (ST2) groups. Animals were euthanized after a 16-week treatment, and blood glucose (BG), glycosylated hemoglobin (HbA1c), urinary albumin excretion rate (AER), serum creatinine (Scr), creatinine clearance rate (Ccr), active glucagon-like peptide-1 (GLP-1) levels, kidney hypertrophy index, and renal pathohistology were determined. Immunohistochemical methods and real-time polymerase chain reaction (PCR) were used to detect protein and mRNA expression of podocalyxin, ERK1/2, GLP-1 receptor (GLP-1R) and transforming growth factor-β (TGF-β). After 16 weeks, BG, AER, Scr, HbA1c and the kidney hypertrophy index were all significantly decreased (p < 0.05) in ST1 and ST2 groups, while Ccr and active GLP-1 levels were increased (p < 0.05), with changes more pronounced in ST2 (p < 0.05). Glomerular pathological lesions were also improved following sitagliptin treatment, especially in ST2. Immunohistochemical and real-time PCR revealed that protein and mRNA expression levels of podocalyxin and GLP-1R were increased significantly in ST1 and ST2, while expression of ERK1/2 and TGF-β was decreased (p < 0.05). Sitagliptin therefore delayed DN progression, possibly via the inhibition of ERK1/2 signaling and promotion of the interaction between GLP-1 and the GLP-1R.

Topics: Animals; Blood Glucose; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Disease Progression; Dose-Response Relationship, Drug; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Hypoglycemic Agents; Male; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Rats; Rats, Wistar; Real-Time Polymerase Chain Reaction; Signal Transduction; Sitagliptin Phosphate; Transforming Growth Factor beta

This study was aimed to investigate the therapeutic potential of coenzyme Q10 and its combination with sitagliptin in experimentally induced diabetic nephropathy. The diabetic rats were treated with coenzyme Q10 or sitagliptin and their concomitant administration. Various parameters of renal function like serum creatinine, urea, uric acid and markers of oxidative stress such as renal malondialdehyde content (MDA), glutathione (GSH) level and superoxide dismutase (SOD), catalase activities were measured. TNF-α, TGF-β, MPO activity and nitrite content were estimated in renal tissue with histopathological observation. Diabetic rats showed a significant reduction in renal function, which was reflected with an increase in serum creatinine, urea and uric acid levels. Streptozotocin-nicotinamide caused renal tubular damage with a higher MDA level, depletion of SOD and CAT activity and GSH level. In addition, TNF-α, TGF- β, MPO activity and nitrite content were significantly increased in diabetic rats. Treatment with coenzyme Q10 or sitagliptin and their co-administration ameliorated STZ-nicotinamide-induced renal damage which was reflected by decreased oxidative stress, TNF-α, TGF-β, MPO activity, nitrite content along with histopathological changes. To conclude, concomitant administration of coenzyme Q10 and sitagliptin showed a better renoprotective effect than coenzyme Q10 or sitagliptin when given alone.

Topics: Animals; Antioxidants; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Drug Therapy, Combination; Kidney Function Tests; Oxidative Stress; Protective Agents; Rats; Sitagliptin Phosphate; Treatment Outcome; Ubiquinone

Hyperglycemia is associated with increased mortality and morbidity in patients with type 2 diabetes mellitus (T2DM) who are undergoing dialysis. Although dipeptidyl peptidase-4 (DPP-4) inhibitors have been widely used in end-stage renal disease (ESRD) patients with T2DM, there are few studies on their efficacy in this population. We studied the effect of 3 different DPP-4 inhibitors on metabolic parameters in ESRD patients with T2DM.Two hundred ESRD patients with T2DM who were treated with DPP-4 inhibitors (sitagliptin, vildagliptin, or linagliptin) were enrolled and analyzed retrospectively. The changes in glycated hemoglobin (HbA1c), fasting plasma glucose, and lipid profiles were assessed before and after 3 months of treatment with DPP-4 inhibitors. Subgroup analysis was done for each hemodialysis (HD) and peritoneal dialysis (PD) group.There was no significant difference in the decrease in the HbA1c level among sitagliptin, vildagliptin, and linagliptin treatment groups (-0.74 ± 1.57, -0.39 ± 1.45, and -0.08 ± 1.40, respectively, P = 0.076). The changes in fasting blood glucose and lipid profiles were also not significantly different. In HD patients (n = 115), there was no difference in the HbA1c level among the 3 groups. In contrast, in PD patients (n = 85), HbA1c was reduced more after 3 months of treatment with sitagliptin compared with vildagliptin and linagliptin (-1.58 ± 0.95, -0.46 ± 0.98, -0.04 ± 1.22, respectively, P = 0.001).There was no significant difference in the glucose-lowering effect between the different DPP-4 inhibitors tested in ESRD patients. In PD patients, sitagliptin tends to lower the HbA1c level more than the other inhibitors. The glucose-lowering efficacy of the 3 DPP-4 inhibitors was comparable.

Topics: Adamantane; Blood Glucose; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Female; Glycated Hemoglobin; Humans; Kidney Failure, Chronic; Linagliptin; Lipids; Male; Middle Aged; Nitriles; Peritoneal Dialysis; Pyrrolidines; Renal Dialysis; Retrospective Studies; Sitagliptin Phosphate; Treatment Outcome; Vildagliptin

We investigated the change in the urine albumin-to-creatinine ratio (ACR) to examine the effect of sitagliptin on diabetic nephropathy.. Sitagliptin at a dose of 50 mg was administered to 247 outpatients with type 2 diabetes. Data were collected on the patients' laboratory results (including the ACR), blood pressure, and body weight. Clinical data were compared before and after 3 months' administration of sitagliptin.. The ACR changed from 150.0 ± 538.6 mg/gCre to 148.3 ± 764.6 mg/gCre over 3 months. In the patients with micro- and macro-albuminuria, the ACR after 3 months significantly decreased compared with the baseline (P = 0.04 and P = 0.02, respectively). The subjects whose ACR decreased experienced significantly larger decreases over the 3-month period in blood pressure and estimated glomerular filtration rate (eGFR) than the other subjects. There was no significant correlation between change in ACR (ΔACR) and change in hemoglobin A1c (ΔHbA1c) during 3 months (r = 0.04, P = 0.59), but there was a significant correlation between change in ΔACR and change in systolic blood pressure (r = 0.16, P = 0.03). Multiple regression analysis revealed that the significant predictors for ΔACR were change in systolic blood pressure (β = 0.21, P = 0.016) and change in eGFR (β = 0.20, P = 0.024) over 3 months (r = 0.35, P = 0.04).. Sitagliptin reduces the ACR through decreasing both blood pressure and eGFR, with no correlation with a decrease in HbA1c over a 3-month period. These results may reflect the direct action of sitagliptin on the kidneys.

Topics: Albuminuria; Blood Pressure; Creatinine; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Female; Glomerular Filtration Rate; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Kidney Function Tests; Male; Middle Aged; Pyrazines; Sitagliptin Phosphate; Triazoles

Topics: Coronary Disease; Diabetes Complications; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Early Medical Intervention; Glycated Hemoglobin; Humans; Metformin; Sitagliptin Phosphate

Topics: Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Humans; Pyrazines; Sitagliptin Phosphate; Triazoles

Topics: Aged; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Drug Substitution; Drug Therapy, Combination; Glyburide; Humans; Hypoglycemia; Hypoglycemic Agents; Kidney Failure, Chronic; Kidney Function Tests; Male; Metformin; Pyrazines; Sitagliptin Phosphate; Triazoles

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 (+/+) were treated for 6 weeks with vehicle (control) or sitagliptin (10 mg/kg/bw). Blood/serum glucose, HbA1c, insulin, Total-c, TGs, urea, and creatinine were assessed, as well as kidney glomerular and tubulointerstitial lesions (interstitial fibrosis/tubular atrophy), using a semiquantitative rating from 0 (absent/normal) to 3 (severe and extensive damage). Vascular lesions were scored from 0-2. Sitagliptin in the diabetic rats promoted an amelioration of glycemia, HbA1c, Total-c, and TGs, accompanied by a partial prevention of insulinopenia. Furthermore, together with urea increment prevention, renal lesions were ameliorated in the diabetic rats, including glomerular, tubulointerstitial, and vascular lesions, accompanied by reduced lipid peroxidation. In conclusion, chronic low-dose sitagliptin treatment was able to ameliorate diabetic nephropathy, which might represent a key step forward in the management of T2DM and this serious complication.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Disease Models, Animal; Dose-Response Relationship, Drug; Insulin; Kidney Glomerulus; Lipid Peroxidation; Lipids; Male; Obesity; Pyrazines; Rats; Rats, Zucker; Sitagliptin Phosphate; Treatment Outcome; Triazoles

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

Dipeptidyl peptidase IV converts neuropeptide Y(1-36) (Y(1)-receptor agonist released from renal sympathetic nerves) to neuropeptide Y(3-36) (selective Y(2)-receptor agonist). Previous studies suggest that Y(1), but not Y(2), receptors enhance renovascular responses to angiotensin II in kidneys from genetically-susceptible animals. Therefore, we hypothesized that inhibition of dipeptidyl peptidase IV with sitagliptin (antidiabetic drug) would augment the ability of exogenous and endogenous neuropeptide Y(1-36) to enhance renal vascular responses to angiotensin II in kidneys from spontaneously hypertensive rats. This hypothesis was tested using 3 protocols in isolated perfused kidneys. Results from Protocol 1: Exogenous neuropeptide Y(1-36) enhanced renovascular responses to angiotensin II. This effect of neuropeptide Y(1-36) was blocked by BIBP3226 (selective Y(1) receptor antagonist); Exogenous neuropeptide Y(3-36) did not enhance renovascular responses to angiotensin II. Results from Protocol 2: Sitagliptin augmented the ability of exogenous neuropeptide Y(1-36) to enhance renovascular responses to angiotensin II. This effect of sitagliptin was blocked by BIBP3226. Results from Protocol 3: Renal sympathetic nerve stimulation enhanced renovascular responses to angiotensin II; this enhancement was augmented by sitagliptin and abolished by BIBP3226. Neuropeptide Y(1-36) via Y(1) receptors enhances renovascular responses to angiotensin II in kidneys from genetically hypertensive animals. Sitagliptin, by blocking dipeptidyl peptidase IV, prevents metabolism of neuropeptide Y(1-36) and thereby increases the effects of neuropeptide Y(1-36) released from renal sympathetic nerves on Y(1) receptors leading to augmentation of neuropeptide Y(1-36)-induced enhancement of the renovascular effects of angiotensin II. The renal effects of dipeptidyl peptidase IV inhibitors in hypertensive diabetic patients merit a closer examination.

Topics: Angiotensin II; Animals; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Drug Synergism; Hypertension, Renal; Kidney; Male; Neuropeptide Y; Peptide Fragments; Pyrazines; Rats; Rats, Inbred SHR; Renal Circulation; Sitagliptin Phosphate; Sympathetic Nervous System; Triazoles; Vasoconstrictor Agents