1
|
Impact of discontinuation of fish oil after pioglitazone–fish oil combination therapy in diabetic KK mice. J Nutr Biochem 2020; 76:108265. [DOI: 10.1016/j.jnutbio.2019.108265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 10/05/2019] [Accepted: 10/29/2019] [Indexed: 12/12/2022]
|
2
|
Kita K, Noritake K, Mano Y. Application of a Volumetric Absorptive Microsampling Device to a Pharmacokinetic Study of Tacrolimus in Rats: Comparison with Wet Blood and Plasma. Eur J Drug Metab Pharmacokinet 2019; 44:91-102. [PMID: 29943105 DOI: 10.1007/s13318-018-0493-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND OBJECTIVES Volumetric absorptive microsampling (VAMS) devices are useful for sampling a smaller volume of blood from rodents in the preclinical setting. In the present study, we evaluated the proof of concept of a VAMS device by comparing the pharmacokinetic data of tacrolimus in rats among dried blood in VAMS, wet blood, and plasma. METHODS Tacrolimus was administered orally, to rats, at a dose of 10 mg/kg. Only 10 μL aliquots of blood were absorbed by VAMS devices at designated time points. Tacrolimus was extracted with a methanol-water mixture (1:1, v/v) via sonication. Tacrolimus levels in wet blood (10 μL) and plasma (10 μL) were quantified after protein precipitation. RESULTS Tacrolimus in VAMS devices was quantifiable from 0.2 ng/mL using high-performance liquid chromatography with tandem mass spectrometer. Accuracy and precision were within the acceptance criteria. Bland-Altman plots showed that tacrolimus concentrations in VAMS devices were similar to those in wet blood, regardless of tacrolimus levels. On the other hand, tacrolimus levels in plasma were different from those in VAMS devices, especially at lower concentrations, likely due to partition of tacrolimus to blood cells. However, pharmacokinetic parameters were comparable among the three matrices. CONCLUSIONS Collectively, these findings suggest that the VAMS device can be a useful device for pharmacokinetic studies in rats.
Collapse
Affiliation(s)
- Kenji Kita
- Bioanalysis Unit, Tsukuba R&D Supporting Division, Sunplanet Co., Ltd., Tokodai 5-1-3, Tsukuba-shi, Ibaraki, 300-2635, Japan
| | - Kenichi Noritake
- Preclinical Safety Research Unit, Tsukuba R&D Supporting Division, Sunplanet Co., Ltd., Tokodai 5-1-3, Tsukuba-shi, Ibaraki, 300-2635, Japan
| | - Yuji Mano
- Drug Metabolism and Pharmacokinetics, Eisai Co., Ltd, Tokodai 5-1-3, Tsukuba-shi, Ibaraki, 300-2635, Japan.
| |
Collapse
|
3
|
Tsai SF, Hsieh CC, Wu MJ, Chen CH, Lin TH, Hsieh M. Novel findings of secreted cyclophilin A in diabetic nephropathy and its association with renal protection of dipeptidyl peptidase 4 inhibitor. Clin Chim Acta 2016; 463:181-192. [PMID: 27823952 DOI: 10.1016/j.cca.2016.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND Our previous clinical indicated that urinary cyclophilin A was a good marker for diabetic nephropathy. METHODS We used animal and cell models of diabetic nephropathy to examine the role of cyclophilin A in disease progression. RESULTS Significantly increased urinary cyclophilin A could be detected in db/db at the 8th week. Linagliptin (3mg/kg/day and 15mg/kg/day) could suppress urinary 8-hydroxy-2'-deoxyguanosine at the 8th and 16th week but only the high dose Linagliption could suppress cyclophilin A at the 8th week. Compared to 8-hydroxy-2'-deoxyguanosine, cyclophilin A was a stronger, earlier, and more sensitive marker. Immunohistochemical staining for cyclophilin A was also positive for db/db. In cell studies, oxidative stress and hyperglycemia could stimulate MES-13 and HK-2 cells to secrete cyclophilin A. Hyperglycemia stimulated HK-2 cells to secrete TGFβ1, which caused secretion of cyclophilin A. The secreted cyclophilin A further stimulated CD 147 to move outward from cytosol onto cell membrane in confocal microscopy, which was associated with the p38 MAPK pathway in the downstream. CONCLUSIONS Secreted cyclophilin A may play an important role in diabetic nephropathy in the mouse model and is associated with TGFβ1, CD 147, and the p38 MAPK pathway.
Collapse
Affiliation(s)
- Shang-Feng Tsai
- Division of Nephrology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan; School of Medicine, China Medical University, Taichung, Taiwan; Departments of Life Science, Tunghai University, Taichung, Taiwan; School of Medicine Chung Shan Medical University, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chang-Chi Hsieh
- Departments of Animal Science and Biotechnology, Tunghai University, Taichung, Taiwan
| | - Ming-Ju Wu
- Division of Nephrology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan; School of Medicine Chung Shan Medical University, Taiwan
| | - Cheng-Hsu Chen
- Division of Nephrology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan; School of Medicine, China Medical University, Taichung, Taiwan; Departments of Life Science, Tunghai University, Taichung, Taiwan; School of Medicine Chung Shan Medical University, Taiwan
| | - Ting-Hui Lin
- Department of Biomedical Sciences, Chung Shan Medical University, Taiwan
| | - Mingli Hsieh
- Division of Nephrology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
| |
Collapse
|
4
|
Blood pressure and glucose independent renoprotective effects of dipeptidyl peptidase-4 inhibition in a mouse model of type-2 diabetic nephropathy. J Hypertens 2016; 32:2211-23; discussion 2223. [PMID: 25215436 DOI: 10.1097/hjh.0000000000000328] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Despite the beneficial effects of type 4 dipeptidyl peptidase (DPP-4) inhibitors on glucose levels, its effects on diabetic nephropathy remain unclear. METHOD This study examined the long-term renoprotective effects of DPP-4 inhibitor linagliptin in db/db mice, a model of type 2 diabetes. Results were compared with the known beneficial effects of renin-angiotensin system blockade by enalapril. Ten-week-old male diabetic db/db mice were treated for 3 months with either vehicle (n = 10), 3 mg linagliptin/kg per day (n = 8), or 20 mg enalapril/kg per day (n = 10). Heterozygous db/m mice treated with vehicle served as healthy controls (n = 8). RESULTS Neither linagliptin nor enalapril had significant effects on the parameters of glucose metabolism or blood pressure in diabetic db/db mice. However, linagliptin treatment reduced albuminuria and attenuated kidney injury. In addition, expression of podocyte marker podocalyxin was normalized. We also analysed DPP-4 expression by immunofluorescence in human kidney biopsies and detected upregulation of DPP-4 in the glomeruli of patients with diabetic nephropathy, suggesting that our findings might be of relevance for human kidney disease as well. CONCLUSION Treatment with DPP-4 inhibitor linagliptin delays the progression of diabetic nephropathy damage in a glucose-independent and blood-pressure-independent manner. The observed effects may be because of the attenuation of podocyte injury and inhibition of myofibroblast transformation.
Collapse
|
5
|
Kern M, Klöting N, Mark M, Mayoux E, Klein T, Blüher M. The SGLT2 inhibitor empagliflozin improves insulin sensitivity in db/db mice both as monotherapy and in combination with linagliptin. Metabolism 2016; 65:114-23. [PMID: 26773934 DOI: 10.1016/j.metabol.2015.10.010] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/11/2015] [Accepted: 10/01/2015] [Indexed: 12/24/2022]
Abstract
AIMS Combining different drug classes to improve glycemic control is one treatment strategy for type 2 diabetes. The effects on insulin sensitivity of long-term treatment with the sodium glucose co-transporter 2 (SGLT2) inhibitor empagliflozin alone or co-administered with the dipeptidyl peptidase-4 inhibitor linagliptin (both approved antidiabetes drugs) were investigated in mice using euglycemic-hyperinsulinemic clamps. MATERIALS AND METHODS db/db mice (n=15/group) were treated for 8weeks with 10mg/kg/day empagliflozin monotherapy, 10mg/kg/day empagliflozin plus 3mg/kg/day linagliptin combination therapy, or 3mg/kg/day linagliptin monotherapy. At the end of the study, euglycemic-hyperinsulinemic clamp studies were performed 4days after the last dose of treatment. RESULTS HbA1c and 2-hour fasting glucose concentrations were improved with empagliflozin monotherapy and combination therapy compared with vehicle and linagliptin monotherapy. During the clamp, glucose disposal rates increased and hepatic glucose production decreased with empagliflozin monotherapy and combination therapy compared with vehicle and linagliptin monotherapy. Glucose uptake in liver and kidney was higher with empagliflozin monotherapy and combination therapy compared with vehicle; glucose uptake into both muscle and adipose tissue was only affected by linagliptin treatment. Empagliflozin and combination therapy altered the expression of genes involved in the inflammatory response, fatty acid synthesis and oxidation. CONCLUSIONS These findings suggest that the insulin-sensitizing effects of SGLT2 inhibition contribute to improvements in glycemic control in insulin-resistant states.
Collapse
Affiliation(s)
- Matthias Kern
- Department of Medicine, University of Leipzig, Leipzig, Germany
| | - Nora Klöting
- IFB Obesity Diseases, Junior Research Group Animal Models, University of Leipzig, Leipzig, Germany
| | - Michael Mark
- Department of Cardiometabolic Diseases Research, Boehringer Ingelheim Pharma, Biberach, Germany
| | - Eric Mayoux
- Department of Cardiometabolic Diseases Research, Boehringer Ingelheim Pharma, Biberach, Germany
| | - Thomas Klein
- Department of Cardiometabolic Diseases Research, Boehringer Ingelheim Pharma, Biberach, Germany
| | - Matthias Blüher
- Department of Medicine, University of Leipzig, Leipzig, Germany.
| |
Collapse
|
6
|
Ma M, Hasegawa Y, Koibuchi N, Toyama K, Uekawa K, Nakagawa T, Lin B, Kim-Mitsuyama S. DPP-4 inhibition with linagliptin ameliorates cognitive impairment and brain atrophy induced by transient cerebral ischemia in type 2 diabetic mice. Cardiovasc Diabetol 2015; 14:54. [PMID: 25986579 PMCID: PMC4458052 DOI: 10.1186/s12933-015-0218-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/27/2015] [Indexed: 02/07/2023] Open
Abstract
Background It is unclear whether dipeptidylpeptidase-4 (DPP-4) inhibition can counteract the impairment of cognitive function and brain injury caused by transient cerebral ischemia in type 2 diabetes. The present study was undertaken to test our hypothesis that linagliptin, a DPP-4 inhibitor, administration following transient cerebral ischemia can ameliorate cognitive impairment and brain injury in diabetic mice. Methods db/db mice, a model of obese type 2 diabetes, were subjected to transient cerebral ischemia by 17 min of bilateral common carotid artery occlusion (BCCAO), and were administered (1) vehicle or (2) linagliptin for 8 weeks or 1 week. For the long-term experiment on 8 weeks of linagliptin treatment, cognitive function, and volume and neuronal cell number of hippocampus and cortex were estimated in each group of mice. For the short-term experiment on 1 week of linagliptin treatment, cerebral IgG extravasation, Iba-1 positive cell number (reactive microglia), oxidative stress, and claudin-5 and gp91phox protein levels were measured in each group of mice. Results Linagliptin administration almost completely suppressed the circulating DPP-4 activity in db/db mice, but did not significantly reduce blood glucose or ameliorate glucose intolerance in db/db mice. Linagliptin administration following transient cerebral ischemia significantly counteracted cognitive impairment in diabetic mice, as estimated by water maze test and passive avoidance test. Linagliptin administration ameliorated the decrease in cerebral volume and neuronal cell number in hippocampus and cortex of diabetic mice. Linagliptin administration significantly reduced the increase in cerebral IgG extravasation and the increase in reactive microglia caused by transient cerebral ischemia in diabetic mice. Furthermore, linagliptin significantly suppressed the increase in cerebral oxidative stress in transient cerebral ischemia-subjected diabetic mice. Furthermore, linagliptin significantly increased cerebral claudin-5 and significantly decreased gp91phox in diabetic mice subjected to transient cerebral ischemia. Conclusions DPP-4 inhibition with linagliptin counteracted cognitive impairment and brain atrophy induced by transient cerebral ischemia in diabetic mice, independently of blood glucose lowering effect. This cerebroprotective effect of linagliptin was associated with the suppression of blood-brain barrier disruption and the attenuation of cerebral oxidative stress. Thus, our present work highlights DPP-4 inhibition as a promising therapeutic strategy for cognitive impairment and cerebral vascular complications in type 2 diabetes.
Collapse
Affiliation(s)
- MingJie Ma
- Department of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
| | - Yu Hasegawa
- Department of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
| | - Nobutaka Koibuchi
- Department of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
| | - Kensuke Toyama
- Department of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
| | - Ken Uekawa
- Department of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
| | - Takashi Nakagawa
- Department of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
| | - Bowen Lin
- Department of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
| | - Shokei Kim-Mitsuyama
- Department of Pharmacology and Molecular Therapeutics, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
| |
Collapse
|
7
|
Koga M, Engberding N, Dikalova AE, Chang KH, Seidel-Rogol B, Long JS, Lassègue B, Jo H, Griendling KK. The bone morphogenic protein inhibitor, noggin, reduces glycemia and vascular inflammation in db/db mice. Am J Physiol Heart Circ Physiol 2013; 305:H747-55. [PMID: 23812391 DOI: 10.1152/ajpheart.00825.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular diseases frequently accompany diabetes mellitus. Based on the current understanding of atherosclerosis as an inflammatory disorder of the vascular wall, it has been speculated that diabetes may accelerate atherosclerosis by inducing a proinflammatory milieu in the vasculature. ANG II and bone morphogenic proteins (BMPs) have been implicated in vascular inflammation. We evaluated the effect of angiotensin receptor blockade by valsartan and BMP inhibition by noggin on markers of vascular inflammation in a mouse model of diabetes. Noggin had no effect on blood pressure but decreased serum glucose levels, whereas valsartan significantly decreased blood pressure, but not serum glucose. Both inhibitors reduced reactive oxygen species production in the aorta. Additionally, noggin and valsartan diminish gene transcription and protein expression of various inflammatory molecules in the vascular wall. These observations indicate that although both inhibitors block superoxide production and have similar effects on inflammatory gene expression, glycemia and blood pressure may represent a secondary target differentially affected by noggin and valsartan. Our data clearly identify the BMP pathway as a potentially potent therapeutic target in diabetic inflammatory vascular disease.
Collapse
Affiliation(s)
- Mitsuhisa Koga
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, Georgia; and
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Takahashi A, Asakura M, Ito S, Min KD, Shindo K, Yan Y, Liao Y, Yamazaki S, Sanada S, Asano Y, Ishibashi-Ueda H, Takashima S, Minamino T, Asanuma H, Mochizuki N, Kitakaze M. Dipeptidyl-peptidase IV inhibition improves pathophysiology of heart failure and increases survival rate in pressure-overloaded mice. Am J Physiol Heart Circ Physiol 2013; 304:H1361-9. [DOI: 10.1152/ajpheart.00454.2012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Incretin hormones, including glucagon-like peptide-1 (GLP-1), a target for diabetes mellitus (DM) treatment, are associated with cardioprotection. As dipeptidyl-peptidase IV (DPP-IV) inhibition increases plasma GLP-1 levels in vivo, we investigated the cardioprotective effects of the DPP-IV inhibitor vildagliptin in a murine heart failure (HF) model. We induced transverse aortic constriction (TAC) in C57BL/6J mice, simulating pressure-overloaded cardiac hypertrophy and HF. TAC or sham-operated mice were treated with or without vildagliptin. An intraperitoneal glucose tolerance test revealed that blood glucose levels were higher in the TAC than in sham-operated mice, and these levels improved with vildagliptin administration in both groups. Vildagliptin increased plasma GLP-1 levels in the TAC mice and ameliorated TAC-induced left ventricular enlargement and dysfunction. Vildagliptin palliated both myocardial apoptosis and fibrosis in TAC mice, demonstrated by histological, gene and protein expression analyses, and improved survival rate on day 28 (TAC with vildagliptin, 67.5%; TAC without vildagliptin, 41.5%; P < 0.05). Vildagliptin improved cardiac dysfunction and overall survival in the TAC mice, both by improving impaired glucose tolerance and by increasing GLP-1 levels. DPP-IV inhibitors represent a candidate treatment for HF patients with or without DM.
Collapse
Affiliation(s)
- Ayako Takahashi
- Department of Cell Biology,
- Department of Molecular Cardiology and
| | | | | | | | - Kazuhiro Shindo
- Department of Cell Biology,
- Department of Molecular Cardiology and
| | - Yi Yan
- Department of Molecular Cardiology and
| | - Yulin Liao
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China; and
| | | | - Shoji Sanada
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshihiro Asano
- Department of Molecular Cardiology and
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | | | - Seiji Takashima
- Department of Molecular Cardiology and
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tetsuo Minamino
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hiroshi Asanuma
- Department of Cardiology, Kyoto Prefectural University School of Medicine, Kyoto, Japan
| | | | | |
Collapse
|
9
|
Combined treatment with low-dose pioglitazone and beraprost sodium improves glucose intolerance without causing body weight gain. Diabetol Int 2013. [DOI: 10.1007/s13340-013-0117-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
10
|
Fadini GP, Albiero M, Menegazzo L, de Kreutzenberg SV, Avogaro A. The increased dipeptidyl peptidase-4 activity is not counteracted by optimized glucose control in type 2 diabetes, but is lower in metformin-treated patients. Diabetes Obes Metab 2012; 14:518-22. [PMID: 22171692 DOI: 10.1111/j.1463-1326.2011.01550.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM Dipeptidyl peptidase (DPP)-4 in responsible for incretin degradation and some observations suggest that DPP-4 activity is increased in type 2 diabetes (T2D). We aimed to assess the effect of T2D and glucose control on DPP-4 activity. METHODS In the first set (SET1) of patients, we compared plasma DPP-4 activity between 30 T2D and 20 age- and sex-matched non-diabetic subjects. In the second set (SET2), we measured serum DPP-4 activity in 42 T2D patients before and after a trial of glucose control achieved by add-on basal insulin therapy (NCT00699686). Serum/plasma DPP-4 activity was determined using chromogenic and fluorigenic substrates, as well as several positive and negative controls. RESULTS In SET1, plasma DPP-4 activity was significantly higher in T2D vs. controls (32.2 ± 1.2 U/l vs. 21.2 ± 1.1 U/l, p < 10(-6)). From a meta-analysis of the literature, we found that T2D is associated with a 33% increase in DPP-4 activity compared to controls. In SET2, serum DPP-4 activity was not lowered by intensified glucose control, despite an average haemoglobin A1c (HbA1c) reduction of 1.5%. In both sets of diabetic patients, the use of metformin was associated with a significantly lower DPP-4 activity, independently of age, sex, body mass index and HbA1c. CONCLUSION DPP-4 activity is increased in T2D, but is not lowered by glucose control, suggesting that hyperglycaemia is not a direct determinant of DPP-4 activity. However, metformin may indirectly reduce DPP-4 activity.
Collapse
Affiliation(s)
- Gian P Fadini
- Department of Clinical and Experimental Medicine, University of Padova, Padova, Italy.
| | | | | | | | | |
Collapse
|
11
|
Nagamatsu S, Ohara-Imaizumi M, Nakamichi Y, Aoyagi K, Nishiwaki C. DPP-4 inhibitor des-F-sitagliptin treatment increased insulin exocytosis from db/db mice β cells. Biochem Biophys Res Commun 2011; 412:556-60. [PMID: 21854759 DOI: 10.1016/j.bbrc.2011.07.119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
Abstract
Incretin promotes insulin secretion acutely. Recently, orally-administered DPP-4 inhibitors represent a new class of anti-hyperglycemic agents. Indeed, inhibitors of dipeptidyl peptidase-IV (DPP-4), sitagliptin, has just begun to be widely used as therapeutics for type 2 diabetes. However, the effects of sitagliptin-treatment on insulin exocytosis from single β-cells are yet unknown. We therefore investigated how sitagliptin-treatment in db/db mice affects insulin exocytosis by treating db/db mice with des-F-sitagliptin for 2 weeks. Perfusion studies showed that 2 weeks-sitagliptin treatment potentiated insulin secretion. We then analyzed insulin granule motion and SNARE protein, syntaxin 1, by TIRF imaging system. TIRF imaging of insulin exocytosis showed the increased number of docked insulin granules and increased fusion events from them during first-phase release. In accord with insulin exocytosis data, des-F-sitagliptin-treatment increased the number of syntaxin 1 clusters on the plasma membrane. Thus, our data demonstrated that 2-weeks des-F-sitagliptin-treatment increased the fusion events of insulin granules, probably via increased number of docked insulin granules and that of syntaxin 1 clusters.
Collapse
Affiliation(s)
- Shinya Nagamatsu
- Department of Biochemistry, Kyorin University School of Medicine, Mitaka, Tokyo, Japan.
| | | | | | | | | |
Collapse
|
12
|
Davis JA, Singh S, Sethi S, Roy S, Mittra S, Rayasam G, Bansal V, Sattigeri J, Ray A. Nature of action of Sitagliptin, the dipeptidyl peptidase-IV inhibitor in diabetic animals. Indian J Pharmacol 2011; 42:229-33. [PMID: 20927248 PMCID: PMC2941613 DOI: 10.4103/0253-7613.68425] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 02/02/2010] [Accepted: 06/21/2010] [Indexed: 01/22/2023] Open
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 IC50 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 IC50 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.
Collapse
Affiliation(s)
- Joseph A Davis
- Department of Pharmacology, New Drug Discovery Research, Ranbaxy Research Laboratories, Gurgaon, Haryana, India
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Sharma S, Misra CS, Arumugam S, Roy S, Shah V, Davis JA, Shirumalla RK, Ray A. Antidiabetic activity of resveratrol, a known SIRT1 activator in a genetic model for type-2 diabetes. Phytother Res 2010; 25:67-73. [DOI: 10.1002/ptr.3221] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
14
|
Kang YJ, Jung UJ, Lee MK, Kim HJ, Jeon SM, Park YB, Chung HG, Baek NI, Lee KT, Jeong TS, Choi MS. Eupatilin, isolated from Artemisia princeps Pampanini, enhances hepatic glucose metabolism and pancreatic beta-cell function in type 2 diabetic mice. Diabetes Res Clin Pract 2008; 82:25-32. [PMID: 18703253 DOI: 10.1016/j.diabres.2008.06.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 05/22/2008] [Accepted: 06/05/2008] [Indexed: 11/30/2022]
Abstract
Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) was isolated from Artemisia princeps to investigate the dose-response effects on blood glucose regulation and pancreatic beta-cell function in type 2 diabetic mice. Db/db mice were divided into control (eupatilin-free, AIN-76 standard diet), low-Eupa (0.005g/100g diet) and high-Eupa (0.02g/100g diet) groups. The supplementation of eupatilin for 6 weeks significantly lowered fasting blood glucose concentration while it increased hepatic glycogen content. In particular, high-Eupa reduced hemoglobin A(1c) and plasma glucagon levels along with a simultaneous increase in plasma insulin and adiponectin levels. The supplementation of eupatilin significantly lowered hepatic glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities, while it increased glucokinase activity in the liver. The pancreatic insulin concentration was higher in the eupatilin-supplemented groups. Also the pancreatic insulin concentration of eupatilin groups was higher than the control group. These results suggest that eupatilin played the role of an antidiabetic functional component in A. princeps by enhancing hepatic and plasma glucose metabolism as well as by increasing insulin secretion in type 2 diabetic mice.
Collapse
Affiliation(s)
- Young-Jin Kang
- Department of Food Science and Nutrition, Kyungpook National University, Daegu 702-701, South Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|