Dipeptidyl Peptidase-4 Activity Research Articles

Neuroprotective effect of genistein on cognitive impairment in vascular dementia experimental mice model

The present study aims to determine the neuroprotective efficacy of genistein on vascular dementia in experimental model mice and explore the underlying mechanisms. To induce vascular dementia, chronic bilateral common carotid artery occlusion was performed on female mice brain by occluding both common carotid arteries for 30 min followed by 24 h reperfusion to induce neuronal injury. After surgery, the mice were treated daily by oral administration of genistein (5.0, and 10.0 mg/kg, i.p., o.d.) for one months. The cognition function of treated mice, were evaluated by Morris Water Maze (MWM) test, neurological functions measured as short-term memory and motor performance. In addition, cerebral infarct size, oxidative damage, mitochondrial activity in terms of neuronal apoptosis and cellular viability, Nissl and TUNEL staining were chosen to assess neuronal damage within the hippocampal CA1 area. In present study, there was an increase in cognitive impairment and neuronal damages within CA1 hippocampal subregion caused by chronic cerebral hypoperfusion. Genistein administration significantly counteracted cognitive impairment and re-established motor performance in vascular dementia in mice. Genistein was able to prevent cognitive deficits, and reversed CCH-induced hippocampal neuronal loss and apoptosis. Genistein treatment significantly reduced neuronal apoptosis and increased cellular viability, almost completely suppressed the circulating dipeptidyl peptidase-4 activity, and enhanced glucagon-like peptide-1 concentration in vascular dementia in experimental model mice. This study suggests that genistein has potent neuroprotective activity against chronic cerebral hypoperfusion and may be considered as a potential treatment for cognitive deficits and neuronal injury in the hippocampal CA1 area.

Oleuropein-enriched chocolate by extra virgin olive oil blunts hyperglycaemia in diabetic patients: Results from a one-time 2-hour post-prandial cross over study.

Oleuropein, a component of extra virgin olive oil (EVOO), reduces post-prandial glycemia with a mechanism counteracting oxidative stress-mediated incretin down-regulation. In this study we evaluated if the intake of an oleuropein-enriched chocolate could have positive effects on glycaemia and insulin levels in patients with type 2 diabetes mellitus (T2DM) and healthy subjects (HS). Twenty-five consecutive T2DM patients and 20 HS were recruited. Participants were randomized to receive 40g oleuropein-enriched chocolate by EVOO or 40g control chocolate spread in a cross-over design. Serum glucose, insulin, glucagon-like peptide-1 (GLP1), and dipeptidyl-peptidase-4 (DPP4) were measured before and 2h after chocolate intake. In T2DM, the pairwise comparisons showed that intake of oleuropein-enriched chocolate was associated with a significantly less increase of blood glucose compared to control; GLM analysis showed a significant difference for treatments with respect to glucose (p=0.04), GLP1 (p<0.001) and DPP-4 activity (p=0.01). In HS, the pairwise comparisons showed that, after oleuropein-enriched chocolate intake, blood glucose concentration and DPP4 activity did not change; conversely a significant increase was observed for insulin and GLP1. After control chocolate intake, a significant increase for blood glucose, insulin levels and DPP4 activity were observed while GLP1 did not change. The study shows that using EVOO as source of oleuropein administration of 40g oleuropein-enriched chocolate is associated with a modest increase or no change of glycemia in T2DM and HS respectively, via an incretin-mediated mechanism.

The effects of DPP4 inhibitors on the levels of plasma catecholamines and their metabolites in patients with type 2 diabetes

AimsDipeptidyl peptidase 4 inhibitors (DPP4Is) can increase sympathetic activity. We aimed to evaluate the direct association between serum DPP4 activity and sympathetic activity in humans. MethodsFasting serum DPP4 activity and plasma levels of catecholamines and their metabolites were measured in 211 patients with type 2 diabetes mellitus (T2DM) treated with DPP4I (n = 146) or non-DPP4I therapy (n = 65) and in healthy control subjects (n = 30). ResultsAlthough there were no differences in plasma levels of catecholamines and their metabolites between the DPP4I and non-DPP4I groups, the levels in both of these groups were lower than those in the healthy control group. In DPP4I-treated patients, serum DPP4 activity showed an inverse correlation with plasma levels of norepinephrine (NE) (r = −0.339, p < 0.01), metanephrine (MET) (r = −0.251, p < 0.01) and normetanephrine (r = −0.312, p < 0.001). In addition, plasma MET level showed a weak inverse correlation with serum DPP4 activity in the combined T2DM group. In DPP4I-treated patients, the inverse correlation between DPP4 activity and plasma NE remained significant even after multiple adjustments. ConclusionsOur results suggest that although sympathetic activity is lower in patients with T2DM, the greater the suppression of DPP4 activity by DPP4I therapy, the greater the increase in sympathetic activity is, which may have clinical implications in high risk T2DM patients.

Dipeptidyl peptidase-4 inhibitors can inhibit angiotensin converting enzyme

Angiotensin-1 converting enzyme inhibitors (ACEIs) improve insulin sensitivity. Inhibitors of dipeptidyl peptidase-4 (DPP-4) are anti-diabetic drugs with several cardio-renal effects. Both ACE and DPP-4 share common features. Thus, we tested if they could be inhibited by one inhibitor. First, in silico screening was used to investigate the ability of different DPP-4 inhibitors or ACEIs to interact with DPP-4 and ACE. The results of screening were then extrapolated into animal study. Fifty Sprague Dawley rats were randomly assigned into 5 groups treated with vehicle, captopril, enalapril, linagliptin or sitagliptin. Both low and high doses of each drug were tested. Baseline blood samples and samples at days 1, 8, 10, 14 were used to measure plasma DPP-4 and ACE activities and angiotensin II levels. Active glucagon-like peptide-1 (GLP-1) levels were measured after oral glucose challenge. All tested DPP-4 inhibitors could interact with ACE at a relatively reasonable binding energy while most of the ACEIs only interacted with DPP-4 at a predicted high inhibition constant. In rats, high dose of sitagliptin was able to inhibit ACE activity and reduce angiotensin II levels while linagliptin had only a mild effect. ACEIs did not significantly affect DPP-4 activity or prevent GLP-1 degradation. It seems that some DPP-4 inhibitors could inhibit ACE and this could partially explain the cardio-renal effects of these drugs. Further studies are required to determine if such inhibition could take place in clinical settings.

Association of circulating klotho and dipeptidyl peptidase-4 activity with inflammatory cytokines in elderly patients with Alzheimer's disease

Association of circulating klotho and dipeptidyl peptidase-4 activity with inflammatory cytokines in elderly patients with Alzheimer's disease

30-days effects of vildagliptin on vascular function, plasma viscosity, inflammation, oxidative stress, and intestinal peptides on drug-na\xefve women with diabetes and obesity: a randomized head-to-head metformin-controlled study

BackgroundObesity is the main risk factor for diabetes and excessive visceral fat triggers low-grade inflammatory process, mediated by activation and release of cytokines and high flow of free fatty acids that contribute to insulin resistance, increased oxidative stress, and impaired endothelial function. Metformin and vildagliptin have known vasculoprotective actions, but the value of these drugs on drug-naïve diabetic patients during 30 days use warrants investigation. Our purpose was to observe their effects on endothelial function, oxidative stress, inflammatory biomarkers, and plasma viscosity.Methods38 women with obesity and type 2 diabetes drug-naïve, aged between 19 and 50 years, BMI ≥ 30 kg/m2, were recruited and subjected to measurements of endothelial function, nutritive skin microvascular reactivity, plasma viscosity, inflammatory and oxidative stress biomarkers at baseline and randomized 1:1 to ingest metformin (850 mg twice/day) or vildagliptin (50 mg twice/day) during 30 days, and then, re-evaluated.ResultsNo differences between groups were noticed at baseline. After treatment, vildagliptin promoted an improvement on endothelial-dependent and -independent vasodilatations, at arteriole level, while metformin resulted in improved nutritive microvascular reactivity, at the capillary level. Intragroup analysis showed that vildagliptin reduced insulin, C-peptide and oxidized LDL, and increased adiponectin and glucagon-like peptide-1 while metformin reduced weight, plasma glucose, total cholesterol, HDL-c, LDL-c, and dipeptidyl peptidase-4 activity, with an unexpected increase on tumor necrosis factor-α. No significant difference in plasma viscosity was noted.ConclusionsIn the vascular beds investigated, both drugs used for only 30 days improved endothelial function, through distinct, and possibly, complementary mechanisms on drug-naïve diabetic women.Trial Registration ClinicalTrials.gov: NCT01827280

Late gestational testosterone exposure causes glucose deregulation and elevated cardiac VCAM-1 and DPP-4 activity in rats

Context Increased vascular cell adhesion molecule-1 (VCAM-1) has been reported to be a critical link between obesity and atherosclerotic cardiovascular diseases while dipeptidyl peptidase-4 (DPP-4) has been implicated in the development of disrupted glucose regulation and inflammation. Objective This study aimed to investigate the effect of gestational testosterone exposure on glucose metabolism, atherogenic dyslipidemia, as well as circulating and cardiac VCAM-1, oxidative stress biomarkers and DPP-4 activity in pregnant rats. Methods Pregnant Wistar rats received either vehicle or testosterone (0.5 mg/kg; sc) between gestational days 14 and 19. Results Gestational testosterone exposure caused impaired glucose homeostasis that was accompanied with atherogenic dyslipidemia, elevated circulating and cardiac levels of VCAM-1, uric acid, malondialdehyde as well as increased DPP-4 activity. However, nitric oxide levels were decreased. Conclusion This study shows that gestational testosterone exposure causes glucose deregulation and atherogenic dyslipidemia that is accompanied by increased circulating and cardiac VCAM-1 and DPP-4 activity.

Identification of a Novel Scaffold for Inhibition of Dipeptidyl Peptidase-4.

Dipeptidyl peptidase-4 (DPP-4) is considered a major drug target for type 2 diabetes mellitus (T2DM). In addition to T2DM, a regulatory role of DPP-4 was also found in cardiovascular diseases. Existing DPP-4 inhibitors have been reported to have several adverse effects. In this study, a computer-aided drug design approach and its use to detect a novel class of inhibitor for DPP-4 are reported. Through structure and pharmacophore-based screening, we identified 13 hit compounds from an ∼4-million-compound library. Physical interactions of these hits with DPP-4 were studied using docking and explicit solvent molecular dynamics (MD) simulations. Later, MMPBSA binding energy was calculated for the ligand/protein simulation trajectories to determine the stability of compounds in the binding cavity. These compounds have a novel scaffold and exhibited a stable binding mode. "Best-in-screen" compounds (or their closest available analogs) were resourced and their inhibition of DPP-4 activity was experimentally validated using an in vitro enzyme activity assay in the presence of 100 and 10 μM compounds. These assays identified a compound with a spirochromanone center with 53% inhibition activity at a 100 μM concentration. A further five spirochromanone compounds were synthesized and examined in silico and in vitro; again, one compound showed 53% inhibitory activity action at 100 μM. Overall, this study identified two novel "spirochromanone" compounds that lowered DPP-4 activity by more than ∼50% at 100 μM. This study also showed the impact of fast in silico drug design techniques utilizing virtual screening and MD to identify novel scaffolds to bind and inhibit DPP-4. Spirochromanone motif identified here may be used to design molecules to achieve drug-like inhibitory action against DPP-4.

Increased Plasma Dipeptidyl Peptidase-4 (DPP4) Activity Is an Obesity-Independent Parameter for Glycemic Deregulation in Type 2 Diabetes Patients.

Background: Increase in circulating dipeptidyl peptidase-4 (DPP4) activity and levels has been reported to associate both with hyperglycemia and obesity. Here we aim to decipher the role of enhanced plasma DPP4 activity in obese type 2 diabetes (T2DM) patients.Materials and methods: Plasma DPP4 levels and activity were measured in obese and non-obese newly diagnosed T2DM patients (n = 123). Visceral and subcutaneous adipose tissue DPP4 expression and activity were determined in 43 obese subjects (T2DM = 21 and non-T2DM = 22). 20 subjects undergoing Mini-Gastric Bypass (MGB) surgery were followed up over 4–6 weeks for plasma DPP4.Results: Plasma DPP4 levels and activity both were increased in T2DM patients compared to control group. However, DPP4 levels and not DPP4 activity were increased in obese T2DM patients compared to non-obese T2DM (62.49 ± 26.27 μg/ml vs. 48.4 ± 30.98 μg/ml, respectively, p = 0.028). DPP4 activity in visceral adipose tissue (VAT) from obese T2DM and obese non-T2DM groups were similar (5.05 ± 3.96 nmol/min/ml vs. 5.83 ± 4.13 nmol/min/ml respectively, p = 0.548) in spite of having increased DPP4 expression in the obese T2DM group. Moreover, in obese patients, plasma DPP4 levels and activity did not show any significant change after weight reduction and glycemic control following MGB surgery.Conclusion: Enhanced plasma DPP4 activity in T2DM occurs independently of obesity. Thus, adipose derived DPP4 may not be playing any significant role in glycemic deregulation in obese T2DM patients.

Greater circulating DPP4 activity is associated with impaired flow-mediated dilatation in adults with type 2 diabetes mellitus

Background and aimDipeptidyl peptidase 4 (DPP4) is a key enzyme involved in the regulation of the incretin system exerted by cleaving the glucagon-like peptide 1 (GLP-1); the blockage of DPP4, exerted by the antidiabetic agents DPP4-inhibitors (DPP4-I), results in greater GLP-1 concentration and improved glycaemic control. DPP4 acts also as a pro-inflammatory molecule and mediates vascular damage in experimental models. The relationship between DPP4 activity and endothelial function in diabetes has not been explored yet. Aim of this study was to investigate systemic plasma DPP4 activity in relation to endothelial function in patients with type 2 diabetes mellitus (T2DM). Methods and resultsSixty-two T2DM individuals were recruited in our Diabetes outpatient clinics, Sapienza University, Rome, Italy. All participants underwent complete clinical work-up; endothelial function was evaluated by flow-mediated dilatation (FMD) test; plasma DPP4 activity was assessed by measuring the 7-amino-4-methylcoumarin (AMC) cleavage rate from the synthetic substrate H-glycyl-prolyl-AMC and compared with DPP4 activity measured in sixty-two age-, sex-, BMI-matched non-diabetic subjects.Patients with T2DM had significantly higher DPP4 activity than non-diabetic individuals (211,466 ± 87657 vs 158,087 ± 60267 nmol/min/ml, p < 0.001); in T2DM patients, greater DPP4 activity significantly correlated with lower FMD whereas was not associated with BMI and metabolic control. Greater systemic DPP4 activity was an independent predictor of reduced FMD after adjusting for age, gender and other confounders. ConclusionsCirculating DPP4 activity is increased in individuals with T2DM and associated with signs of endothelial dysfunction such as impaired FMD. DPP4 may negatively affect endothelial function through mechanisms beyond glucose homeostasis and metabolic control.

Влияние ингибитора дипептидилпептидазы-4 на выведение ионов натрия и воды почками у крыс при изменениях водно-солевого баланса

Желудочно-кишечный тракт секретирует широкий спектр пептидов, регулирующих метаболические процессы и влияющих на функции почек и водно-солевой баланс. Эффекты данных биологически активных веществ можно усилить увеличением их периода полужизни путем угнетения фермента дипептидилпептидазы-4. Цель исследования - изучение экскреции ионов натрия и воды при угнетении дипептидилпептидазы-4 вилдаглиптином у крыс с различным состоянием водно-солевого баланса. Методика. Состояния гипернатриемии, гиперосмии или гипоосмии моделировали пероральным введением гипертонического и изотонического растворов NaCl и воды. Результаты. Вилдаглиптин вызвал дозозависимое снижение активности фермента дипептидилпептидазы-4 с максимумом эффекта при дозе 1 мг на 100 г массы тела. Его введение перед гипертонической натриевой нагрузкой увеличивало экскрецию натрия на 56%, усилило реабсорбцию осмотически свободной и свободной от натрия воды. Введение ингибитора дипептидилпептидазы-4 перед изотонической натриевой нагрузкой усиливало экскрецию натрия в той же степени, но не влияло на реабсорбцию воды. Инъекция вилдаглиптина, предваряющая водную нагрузку, вызвала антидиуретическую реакцию почек. Заключение. Блокада дипептидилпептидазы-4 вилдаглиптином способствует выведению из организма избыточного количества натрия и изменению реабсорбции воды в зависимости от концентрации ионов натрия в сыворотке крови, вероятно, за счет увеличения периода циркуляции кишечных регуляторных пептидов, секретирующихся в ответ на пероральные нагрузочные пробы NaCl. Данные процессы ускоряют восстановление водно-солевого гомеостаза в условиях поступления избытка натрия через желудочно-кишечный тракт. The gastrointestinal tract secretes multiple peptides that regulate metabolic processes and influence the kidney function and water-salt balance. The effects of these biologically active substances can be intensified by increasing their half-life through inhibition of the dipeptidyl peptidase-4 (DPP-4) enzyme. The aim of the study was investigation of sodium and water excretion after inhibition of DPP-4 with vildagliptin in rats with different states of the water-salt balance. Methods. The hypernatremic, hyperosmotic and hypoosmotic states were modeled by oral administration of hypertonic and isotonic NaCl solutions or water. Results. Vildagliptin induced a dose-dependent decrease in the DPP-4 activity with a maximum effect of 1 mg per 100 g of body weight. Vildagliptin administration prior to the hypertonic sodium load increased sodium excretion by 56% and stimulated reabsorption of solute-free and sodium-free water. Administration of the DPP-4 inhibitor before the isotonic sodium load increased sodium excretion to the same degree without affecting the water reabsorption. A vildagliptin injection prior to the water load resulted in an antidiuretic response of the kidneys. Conclusion. The inhibition of DPP-4 activity with vildagliptin promoted removal of excessive sodium from the body and changed the water reabsorption depending on the sodium concentration in the blood serum, presumably by prolonging circulation of the intestinal regulatory peptides secreted in response to oral NaCl load tests. These processes accelerate restoration of the water-salt homeostasis in the conditions of excessive sodium delivery through the gastrointestinal tract.

Abelmoschus esculentus subfractions attenuate beta amyloid-induced neuron apoptosis by regulating DPP-4 with improving insulin resistance signals.

The association of Alzheimer disease (AD) and Diabetes (DM) is less clear. Accumulation of beta amyloid (Aβ) and presence of hyperphosphorylated tau (p-tau) are hallmarks of AD, spreading in the region where insulin receptors are also found. Aβ exerts neuron toxicity, and could disturb insulin signaling of phosphatidylinositol 3-kinase (PI3K), glycogen synthase kinase (GSK)-3β and AMP-activated protein kinase (AMPK), but increase IRS-1-Ser307 phosphorylation which is viewed as insulin resistance marker. Previously we reported dipeptidyl peptidase-4 (DPP-4) mediate insulin resistance signals, and Abelmoschus esculentus (AE) subfractions F1 (rich in quercetin glucosides and triterpene ester) and F2 (containing large amount of polysaccharides) attenuate DPP-4-mediated apoptosis. In the present study, we aim to investigate if Aβ induce neuron death by regulating DPP-4 and insulin resistance signals, and the putative effect of F1 and F2. By MTT, microscopy, and Western blotting, we demonstrate treatment of appropriate doses of AE subfractions prevent Aβ-induced neuron apoptosis. F1 attenuate Aβ-induced caspase 3 expression especially at 25 μg/mL, while F2 attenuate caspase 3 activation even at the low dose of 1 μg/mL. Both AE subfractions decrease Aβ-enhanced DPP-4, but increase Aβ-reduced p-AMPK and p-PI3K. The activity analysis reveals that F2 is more valid than F1 to reduce DPP-4 activity. The inhibition of DPP-4 demonstrates it plays the pivotal role in Aβ-induced neuron apoptosis. Moreover, although both F1 and F2 are effective to inhibit p-IRS-1-Ser307, F2 takes advantage to reduce p-Tau while F1 is superior to enhance p-GSK-3β. This implies AE subfractions act on different targets, and could be developed respectively. In conclusion, we demonstrate AE is potential to prevent Aβ-induced neuron damage by regulating DPP-4 and the insulin resistance cascades. AE could be an adjuvant to protect neuron degenerative disease related to Aβ and insulin resistance.

Single-dose escalation study of yogliptin in healthy Chinese volunteers

BackgroundYogliptin is a novel xanthine dipeptidyl peptidase-4 (DPP-4) inhibitor targeting type 2 diabetes. After promising preclinical pharmacological studies, the first human trial of yogliptin was designed. MethodsA randomized, double-blind, parallel, placebo-controlled phase I single-dose escalation study was designed to evaluate the pharmacokinetics, pharmacodynamics, and tolerability after single oral doses of yogliptin in healthy Chinese subjects. Healthy subjects were assigned to nine cohorts, which received a single dose of yogliptin at 2.5, 5, 10, 25, 50, 100, 200, 400, or 600 mg. Two subjects in each cohort received placebo. Blood samples were collected before dosing and up to 192 h afterwards. Urine samples were collected until 120 h after dosing. Plasma and urine drug concentrations were determined using liquid chromatography coupled with tandem mass spectrometry, and DPP-4 activity was measured using a semi-quantitative, fluorescence-based kinetic assay. ResultsA total of 104 subjects were enrolled, 103 of whom completed the study (mean age, 25.3 years; mean weight, 58.8 kg; mean BMI, 21.8 kg/m2). A total of 27 adverse events (AEs) occurred in 25 of 86 yogliptin subjects (29.1%), and 3 AEs occurred in 3 of 18 placebo subjects (16.7%). Yogliptin was absorbed with a median time of maximum observed concentration (Tmax) of 3.0 h and was eliminated slowly with a t1/2 of 25.45–43.84 h. The maximum observed concentration (Cmax) and area under the curve (AUC) varied slightly more than dose-proportionally over the dose range from 2.5 to 400 mg. The fraction of drug excreted in urine ranged from 8.39% to 24.77%. Mean DPP-4 inhibition at 24 h after dosing ranged from 97.7% to 99.5%, and DPP-4 inhibition was >80% for 72 h at doses from 25 to 400 mg. DPP-4 inhibition was >80% for 1 week in the group receiving 400 mg. ConclusionYogliptin was well tolerated in healthy subjects, with no dose-limiting toxicity observed in the range from 2.5 to 600 mg. Yogliptin inhibited plasma DPP-4 activity for 72 h at single doses of 25–200 mg and for 1 week at 400 mg, suggesting that once-weekly dosing of yogliptin is possible in type 2 diabetes patients.Trial Registration: ChiCTR-IIR-17010311 (Chictr.org).

267-LB: Diabetes-induced Insulin Resistance and DPP-4 Activity Can Be Alleviated through the Reduction of M1 Polarization of Adipose Tissue

Dysregulation of M1/M2 polarization in adipose tissues is emerging as a central mechanism underlying the pathogenesis of obesity and comorbidities such as insulin resistance and nonalcoholic fatty liver disease. To define the involvement of dysregulation of M1/M2 polarization of adipose tissues in diabetes and the effect of nondiabetic plasma on M1/M2 polarization of adipose tissue and liver as well as dipeptidyl peptidase-4 (DPP-4) activity in plasma, we purified stromal vascular fractions (SVFs) from diabetic and nondiabetic mice and analyzed their M1/M2 polarization with or without the treatment of nondiabetic plasma. SVF of diabetic mice (Lep-/-) demonstrated a significant increase of M1 but decrease of M2 signature as compared with nondiabetic mice (Lep+/-). Treatment of SVF from adipose tissue of Lep-/- mice with plasma of Lep-/- mice in vitro significantly increased M1 gene signature. Treatment of SVF from adipose tissue of Lep-/- mice with plasma of nondiabetic mice (Lep+/- mice) increased M2 gene signature. Moreover, injection of plasma of nondiabetic mice (Lep+/-) to adipose tissue of diabetic mice (Lep-/-) induces M2 expression of SVF and decreases inflammation of liver and DPP-4 activity of diabetic (Lep-/-) mice. These data suggest that plasma of diabetic mice can induce M1 expression and plasma of nondiabetic mice can induce M2 expression of adipose tissue of diabetic mice. In conclusion, diabetes and obesity-induced insulin resistance, glucose intolerance, and systemic inflammation can be alleviated through the reduction of M1 polarization of adipose tissue. Disclosure L. Chen: None. Funding Taiwan Ministry of Science and Technology (MOST 107-2314-B-010-043-MY3)

1973-P: Deficiency of Protein Deacetylase Sirt3 Enhances Acetylation of Histone H3 and H4 as to Affect Glucose Metabolism through Regulation of Dipeptidyl Peptidase-4 in Mice

Background: Sirt3 is a NAD-dependent deacetylase that regulates lipid metabolism in mice and is related to longevity through modification of epigenome. Sirt3-deficient knockout (KO) mice fed a high-fat diet have been shown to develop obesity and metabolic syndrome-like phenotype. However, the precise mechanism by which they cause glucose intolerance has not been known. To reveal the regulatory mechanism of glucose metabolism through Sirt3, the metabolic parameters in the Sirt3-KO mice were examined. Objective and Methods: The histone acetylation levels in various organs of the Sirt3-KO mice were examined by immunostaining of acetylated histone H3 (H3Ac) and H4 (H4Ac). Blood glucose levels in the Sirt3-KO mice after glucose loading were examined, associated with blood glucagon-like peptide-1 (GLP-1) levels and dipeptidyl peptidase-4 (DPP-4) activity. Gene expressions which were associated with the expressions and functions of GLP-1 and DPP-4 were quantified by qPCR. Results: The Sirt3-KO mice were subjected to an oral glucose tolerance test (OGTT), together with an intraperitoneal glucose tolerance test (ipGTT). OGTT revealed an increase in the blood glucose levels in the KO mice, although ipGTT did not show the increase after the glucose loading. The blood GLP-1 and insulin levels decreased, and the DPP-4 activity increased significantly in the KO mice. qPCR analysis revealed a predominance of Sirt3 expression in the intestinal tract in the wild type mice. The immunostaining of H3Ac and H4Ac showed enhanced intensity in the small intestine and colon, and in the vascular endothelial cells in the KO mice. Conclusion: These results suggest that Sirt3 deficiency impairs the incretin effect by a suppression of the blood GLP-1 levels and causes glucose intolerance. Enhanced acetylation of histone H3 and H4 in the KO mice might relate to the increase in the DPP-4 activity, which lead to the decrease in the GLP-1 levels. Disclosure A. Uto: None. K. Miyashita: Research Support; Self; Johnson &amp; Johnson, Merck &amp; Co., Inc., Novo Nordisk Inc.

440-P: The Effects of DPP-4 Inhibitors on Plasma Catecholamines and Their Metabolites in Patients with Type 2 Diabetes

Previous preclinical and clinical studies have raised a concern that dipeptidyl peptidase 4 inhibitors (DPP-4i) increased sympathetic activity, which may be related with increased risk of heart failure in DPP-4i-treated type 2 diabetics. In this study, we aimed to evaluate the relationship between DPP-4 activity and catecholamine secretion in patients with type 2 diabetes. Patients with type 2 diabetes (n=119) and normal healthy control subjects (n=25) participated in this cross-sectional study which included the measurement of serum DPP-4 activity and plasma levels of epinephrine (Epi), norepinephrine (NE), metanephrine (MET) and normetanephrine (NMET), other blood and urine biochemical tests, and the collection of demographic and clinical data. The median ages of patients with type 2 diabetes and healthy control subjects were 61 and 56 years, respectively. Compared with the control group, patients with type 2 diabetes were associated with lower plasma levels of catecholamines and their metabolites. In DPP-4i-treated diabetic patients (n=86) had lower plasma NMET level compared with other antidiabetic treatment group (n=36) [0.31 (IQR: 0.21, 0.43)] nmol/L vs. 0.41 (0.29, 0.46) nmol/L, p&amp;lt;0.05], while the plasma concentrations of the two catecholamines and MET were comparable. The difference in plasma NMET level between the two treatment groups was not affected by beta-blocker and angiotensin II receptor blocker therapy, respectively. Additionally, in DPP-4i-treated type 2 diabetics, DPP-4 activity showed inverse correlations with plasma levels of NE (r=-0.312, p&amp;lt;0.01) and NMET (r=-0.275, p&amp;lt;0.05). However, those inverse correlations were not observed in the healthy control group and type 2 diabetics treated with non-DPP-4i antidiabetic agents. Our results suggest that DPP-4i treatment in type 2 diabetics affects NE release from sympathetic nerve in a DPP-4 inhibitory action-dependent manner. Disclosure I. Park: None. D. Lee: None. K. Lee: None.

190-LB: Dipeptidyl Peptidase-IV Promotes the Developmental Programming of Chronic Inflammatory Diseases due to Perinatal Exposure to Maternal Obesity

Perinatal exposure to maternal obesity promotes the development of chronic diseases such as cardiovascular (CVD) and metabolic diseases (T2DM) through a process known as developmental programming. The mechanisms of developmental programming are unclear. Dipeptidyl peptidase IV (DPP-4) is a pathogenic aminopeptidase that is upregulated in individuals with chronic diseases and its inhibitors are protective against T2DM and heart failure. DPP-4 can function as a membrane-anchored protein or as a soluble enzyme and can promote metainflammation and increased food intake. We found that DPP-4 enzymatic activity is upregulated over two-fold (P&amp;lt;0.05) in the cord blood of male offspring of women with obesity. Hence, we hypothesized that perinatal exposure to maternal obesity promotes the pathogenesis of cardiometabolic diseases through the activation of DPP-4. To test this hypothesis, we used a mouse model of maternal western style diet (WSD) feeding and found that offspring of WSD (Off-WSD) vs. regular diet (Off-RD) -fed mice have upregulated DPP-4 activity in plasma (two-fold, P&amp;lt;0.05) and PBMC (three-fold, P&amp;lt;0.05). This is concurrent with significantly impaired glucose tolerance, decreased insulin sensitivity, increased adiposity and hepatosteatosis. Systemic inhibition of DPP-4 with Sitagliptin alleviated these pathologies. Immune cells are a major source of plasma DPP-4 and we found that an allogeneic bone marrow transplantation (BMT) of Off-WSD bone marrow to lethally irradiated mice led to a significant increase in DPP-4 activity in plasma and PBMC compared to BMT with Off-RD bone marrow. This is concurrent with significantly increased adiposity, impaired glucose tolerance and decreased insulin sensitivity. In summary, our findings suggest a pathogenic role of DPP-4, and specifically, immune-derived DPP-4, in the developmental programming of chronic inflammatory diseases due to perinatal exposure to maternal obesity. Disclosure K. Montaniel: None. M.S. Bucher: None. A. Maloyan: None. Funding National Institutes of Health; Oregon Health &amp; Science University

DPP4 inhibitors as novel agents in improving survival in patients with prostate cancer: A SEER-Medicare study.

e16532 Background: Dipeptidyl peptidase-4 (DPP4) is a cell surface protein expressed in variable amounts on different tissues and plays a vital role in tumor biology as well as regulation of the immune system. In-vitro studies have shown that the DPP4 biochemical activity is twice as high in prostate cancer cells compared to benign prostate tissues. Furthermore, blocking of DPP4 activity in-vitro was demonstrated to inhibit tumor angiogenesis and tumor invasiveness through a number of cellular mechanisms. Meanwhile, DPP4 expression is modest in normal as well as cancerous pancreatic cells. Methods: Using linked SEER and MEDICARE database, we identified patients with prostate cancer (PRC) or pancreatic cancer (PC) with coexisting type II diabetes mellitus. Furthermore, we analyzed the impact of DPP4 inhibition in the overall survival (OS) in these patients between 2001 and 2013. Analyses were performed using SAS, version 9.4. We excluded patients taking metformin. Results: We identified 7229 patients with PRC and 2401 patients with PC. OS was significantly better in PRC patients taking DPP4 inhibitors (262 patients) with HR 0.75 (95% CI: 0.59-0.97; P = 0.02) compared to those not on DPP4 inhibitors. Meanwhile, for patients with PC, OS was not significantly different between patients taking DPP4 inhibitors (177 patients) compared to those who were not (HR 1.03; 95% CI: 0.88-1.21; P = 0.7). Subgroup analyses of PRC patients demonstrated a trend toward a beneficial effect of DPP4 inhibitors, irrespective of stage (stage I, NR; stage II, HR 0.81; stage III, NR; stage IV, 0.76),use of chemotherapy (HR 0.83 with chemotherapy and HR 0.70 without chemotherapy) or hormonal use (ADT) (HR 0.87 with ADT and HR 0.71 without ADT), prostatectomy (HR 0.50 with prostatectomy and HR 0.77 with no prostatectomy) or radiation (HR 0.89 with radiation and HR 0.64 without radiation). Conclusions: This is the first population-based analysis showing the OS benefit of DPP4 inhibitors in PRC patients. On the other hand, OS was not improved in PC patients taking DPP4 inhibitors likely due to low levels of expression of DPP4 cell surface protein on pancreatic tissues. A prospective trial would help confirm our findings.

Lung infection caused by Pseudomonas aeruginosa in a CD26/DPP4 deficient F344 rat model.

BackgroundPseudomonas aeruginosa (PA) is the most important opportunistic pathogen in causing nosocomial infections and, furthermore, poses a permanent threat for severe chronic infections in patients with cystic fibrosis or COPD. The transmembrane protein CD26 with dipeptidyl peptidase-4 (DPP4) activity shows an increased expression in inflamed tissue. We tested whether CD26/DPP4 deficiency leads to reduced inflammation and decreased structural damage when infected with PA.MethodsCD26/DPP4+ and CD26/DPP4− rats were instilled intratracheally with NaCl (controls) or with PA. Six hours later, bacterial distribution was detected with the in vivo imaging system 200 (IVIS). Lungs were then processed for molecular biology, light and electron microscopy and analyzed qualitatively, quantitatively and stereologically. Bacterial numbers were determined in homogenized lungs.ResultsCompared to saline treated controls, in both infected groups (1) the acinar airspace was significantly increased, (2) the volume density of the alveolar epithelium was significantly decreased, (3) the septal thickness was significantly reduced, (4) more than 40% of the alveolar epithelial surface was damaged, and up to 36% of the epithelial surface was covered with edema. In infected CD26− rats, the increase in lung weight was significantly less pronounced, the portion of edematous alveolar airspace was significantly lower and the part of edema interspersed with PA was decreased significantly.ConclusionsCD26/DPP4 deficiency resulted in reduced pulmonary edema under sublethal PA infection, implicating a role for CD26 in infection progression. The partly pronounced structural damage may mask further possible influences of CD26 on the inflammatory response.

Effects of boschnaloside from Boschniakia rossica on dysglycemia and islet dysfunction in severely diabetic mice through modulating the action of glucagon-like peptide-1

BackgroundBoschniakia rossica is a well-known traditional Chinese medicine for tonifying kidney and improving impotence. Boschnaloside is the major iridoid glycoside in this herb but therapeutic benefits for diabetes remained to be evaluated. Hypothesis/PurposeThe current investigation aims to study the antidiabetic effect and the underlying pharmacological mechanisms. Study design and methodsReceptor binding, cAMP production, Ins secretion, glucagon-like peptide 1 (GLP-1) secretion, and dipeptidyl peptidase-4 activity assays were performed. Therapeutic benefits of orally administrated boschnaloside (150 and 300 mg/kg/day) were evaluated using severely 12-week old female diabetic db/db mice (Hemoglobin A1c >10%). ResultsOral treatment of boschnaloside for 4 weeks improved diabetic symptoms including fasting blood sugar, hemoglobin A1c, glucose intolerance, and Homeostatic Model Assessment of Ins Resistance, accompanied by circulating GLP-1active and adiponectin levels. In addition, bochnaloside treatment improved islet/β cell function associated with an alteration of the pancreatic and duodenal homeobox 1 level. It was shown that boschnaloside interacted with the extracellular domain of GLP-1 receptor and enhanced glucose stimulated Ins secretion. Boschnaloside also augmented the insulinotropic effect of GLP-1. Finally, the presence of boschnaloside caused a reduction of dipeptidyl peptidase-4 activity while enhanced GLP-1 secretion from STC-1 cells. ConclusionIt appears that bochnaloside at oral dosage greater than 150 mg/kg/day exerts antidiabetic effects in vivo through modulating the action of GLP-1.