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Siebner TH, Hove JD, Madelung CF, Hulme OJ, Bendtsen F, Siebner HR, Barløse M. No difference in postprandial mesenteric blood flow between healthy younger and elderly individuals. Sci Rep 2024; 14:8689. [PMID: 38622189 PMCID: PMC11018827 DOI: 10.1038/s41598-024-58111-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/25/2024] [Indexed: 04/17/2024] Open
Abstract
We recently used phase-contrast magnetic resonance imaging (PC-MRI) to demonstrate an attenuated postprandial blood flow response in the superior mesenteric artery (SMA) in patients with Parkinson's disease compared to age- and sex-matched healthy controls. Since both groups showed substantial inter-individual variations, we extended the cohort of controls with a group of young individuals to investigate possible age-related effects. Seventeen healthy young subjects aged < 30 years and 17 elderly subjects aged > 50 years underwent serial PC-MRI to measure the postprandial blood flow response in the SMA after ingestion of a standardized liquid test meal (∼400 kcal). Postprandial blood flow dynamics in SMA did not differ between young and elderly subjects. A noticeable inter-individual variation in postprandial intestinal blood flow increase was found, and approximately 30% of the variation could be explained by the preprandial blood flow. Regardless of age, some subjects showed a remarkable transient SMA blood flow increase immediately after meal intake. This study provides tentative evidence that postprandial blood flow dynamics in SMA in healthy young and elderly subjects do not substantially differ, indicating that age is without impact on vascular response in SMA as an indicator for regulation of mesenteric perfusion in response to food intake.
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Affiliation(s)
- Thomas Hartwig Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.
- Department of Cardiology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.
| | - Jens Dahlgaard Hove
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Department of Cardiology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christopher Fugl Madelung
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Department of Neurology, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark
| | - Oliver James Hulme
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Department of Psychology, Faculty of Social Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Flemming Bendtsen
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Gastrounit, Medical Division, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Neurology, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark
| | - Mads Barløse
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Physiology and Nuclear Medicine, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
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Chook CYB, Cheung YM, Ma KY, Leung FP, Zhu H, Niu QJ, Wong WT, Chen ZY. Physiological concentration of protocatechuic acid directly protects vascular endothelial function against inflammation in diabetes through Akt/eNOS pathway. Front Nutr 2023; 10:1060226. [PMID: 37025617 PMCID: PMC10070727 DOI: 10.3389/fnut.2023.1060226] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 03/06/2023] [Indexed: 04/08/2023] Open
Abstract
Background Cardiovascular diseases (CVDs) have been the major cause of mortality in type 2 diabetes. However, new approaches are still warranted since current diabetic medications, which focus mainly on glycemic control, do not effectively lower cardiovascular mortality rate in diabetic patients. Protocatechuic acid (PCA) is a phenolic acid widely distributed in garlic, onion, cauliflower and other plant-based foods. Given the anti-oxidative effects of PCA in vitro, we hypothesized that PCA would also have direct beneficial effects on endothelial function in addition to the systemic effects on vascular health demonstrated by previous studies. Methods and results Since IL-1β is the major pathological contributor to endothelial dysfunction in diabetes, the anti-inflammatory effects of PCA specific on endothelial cells were further verified by the use of IL-1β-induced inflammation model. Direct incubation of db/db mouse aortas with physiological concentration of PCA significantly ameliorated endothelium-dependent relaxation impairment, as well as reactive oxygen species overproduction mediated by diabetes. In addition to the well-studied anti-oxidative activity, PCA demonstrated strong anti-inflammatory effects by suppressing the pro-inflammatory cytokines MCP1, VCAM1 and ICAM1, as well as increasing the phosphorylation of eNOS and Akt in the inflammatory endothelial cell model induced by the key player in diabetic endothelial dysfunction IL-1β. Upon blocking of Akt phosphorylation, p-eNOS/eNOS remained low and the inhibition of pro-inflammatory cytokines by PCA ceased. Conclusion PCA exerts protection on vascular endothelial function against inflammation through Akt/eNOS pathway, suggesting daily acquisition of PCA may be encouraged for diabetic patients.
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Affiliation(s)
- Chui Yiu Bamboo Chook
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Yiu Ming Cheung
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Ka Ying Ma
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Fung Ping Leung
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Hanyue Zhu
- School of Food Science and Engineering, Foshan University, Foshan, Guangdong, China
| | - Qingshan Jason Niu
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Wing Tak Wong
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- *Correspondence: Wing Tak Wong,
| | - Zhen-Yu Chen
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Zhen-Yu Chen,
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Metabolic regulation and dysregulation of endothelial small conductance calcium activated potassium channels. Eur J Cell Biol 2022; 101:151208. [DOI: 10.1016/j.ejcb.2022.151208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/13/2022] Open
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Akther F, Razan MR, Shaligram S, Graham JL, Stanhope KL, Allen KN, Vázquez-Medina JP, Havel PJ, Rahimian R. Potentiation of Acetylcholine-Induced Relaxation of Aorta in Male UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) Rats: Sex-Specific Responses. Front Physiol 2021; 12:616317. [PMID: 34366875 PMCID: PMC8339592 DOI: 10.3389/fphys.2021.616317] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 05/20/2021] [Indexed: 11/13/2022] Open
Abstract
Previous reports suggest that diabetes may differentially affect the vascular beds of females and males. The objectives of this study were to examine whether there were (1) sex differences in aortic function and (2) alterations in the relative contribution of endothelium-derived relaxing factors in modulating aortic reactivity in UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) rats. Endothelium-dependent vasorelaxation (EDV) in response to acetylcholine (ACh) was measured in aortic rings before and after exposure to pharmacological inhibitors. Relaxation responses to sodium nitroprusside were assessed in endothelium-denuded rings. Moreover, contractile responses to phenylephrine (PE) were measured before and after incubation of aortic rings with a nitric oxide synthase (NOS) inhibitor in the presence of indomethacin. Metabolic parameters and expression of molecules associated with vascular and insulin signaling as well as reactive oxygen species generation were determined. Diabetes slightly but significantly impaired EDV in response to ACh in aortas from females but potentiated the relaxation response in males. The potentiation of EDV in diabetic male aortas was accompanied by a traces of nitric oxide (NO)- and prostanoid-independent relaxation and elevated aortic expression of small- and intermediate conductance Ca2+-activated K+ channels in this group. The smooth muscle sensitivity to NO was not altered, whereas the responsiveness to PE was significantly enhanced in aortas of diabetic groups in both sexes. Endothelium-derived NO during smooth muscle contraction, as assessed by the potentiation of the response to PE after NOS inhibition, was reduced in aortas of diabetic rats regardless of sex. Accordingly, decreases in pAkt and peNOS were observed in aortas from diabetic rats in both sexes compared with controls. Our data suggest that a decrease in insulin sensitivity via pAkt-peNOS-dependent signaling and an increase in oxidative stress may contribute to the elevated contractile responses observed in diabetic aortas in both sexes. This study demonstrates that aortic function in UCD-T2DM rats is altered in both sexes. Here, we provide the first evidence of sexual dimorphism in aortic relaxation in UCD-T2DM rats.
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Affiliation(s)
- Farjana Akther
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
| | - Md Rahatullah Razan
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
| | - Sonali Shaligram
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
| | - James L. Graham
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Kimber L. Stanhope
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Kaitlin N. Allen
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
| | | | - Peter J. Havel
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Roshanak Rahimian
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
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Lee SP, Kuo FY, Cheng JT, Wu MC. GLP-1 mediates the modulating effect of thymoquinone on feeding behaviors in diabetic rats. Diabetes Metab Syndr Obes 2019; 12:873-881. [PMID: 31354323 PMCID: PMC6580122 DOI: 10.2147/dmso.s207596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/09/2019] [Indexed: 12/30/2022] Open
Abstract
Background: Thymoquinone (TQ) is a safe nutrient isolated from the seeds or volatile oil extract of Nigella sativa. In addition to its benefits in glucose regulation, TQ improves feeding disorders in diabetic animals. Glucagon-like peptide-1 (GLP-1) analogs improve glycemic control and ameliorate obesity or hyperphagia. Therefore, the present study aimed to investigate the role of GLP-1 in TQ-induced anorexia. Method: Type 2 diabetes was induced in rats by nicotinamide and streptozotocin injection. TQ was orally administered to diabetic rats at different doses for 45 days. Following TQ treatment, changes in serum glucose levels, GLP-1 concentration, body weight, food intake, and water intake were determined. To further explore the interaction between GLP-1 and TQ, the inhibitor of dipeptidyl peptidase 4, sitagliptin and the GLP-1 receptor antagonist exendin 9-39 (Ex 9-39) were separately administered to TQ- or vehicle-treated diabetic rats. Results: TQ treatment attenuated hyperglycemia and reduced hyperphagy and water intake in streptozotocin-induced diabetic rats in a dose-dependent manner. Moreover, TQ treatment elevated plasma GLP-1 levels compared to those in control rats. The effects of TQ were enhanced by treatment with sitagliptin and reduced by the injection of Ex 9-39 into the brain. In contrast, similar treatment with another antioxidant (either ascorbic acid or N-acetylcysteine) produced the same anorexic effect as TQ without changing the plasma GLP-1 levels in diabetic rats. Therefore, TQ attenuated hyperphagy while increasing plasma GLP-1 levels and had antioxidant-like effects. Conclusion: TQ increased endogenous GLP-1 levels to reduce hyperphagy in diabetic rats.
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Affiliation(s)
- Shu Ping Lee
- Department of Food Science, College of Agriculture, National Pingtung University of Science and Technology, Pingtung91201, Taiwan
| | - Feng Yu Kuo
- Department of Food Science, College of Agriculture, National Pingtung University of Science and Technology, Pingtung91201, Taiwan
- Cardiovascular Center, Veterans General Hospital, Kaohsiung City81362, Taiwan
| | - Juei-Tang Cheng
- Department of Medical Research, Chi-Mei Medical Center, Tainan City71003, Taiwan
- Institute of Medical Science, College of Health Science, Chang Jung Christian University, Tainan City71101, Taiwan
- Correspondence: Juei-Tang ChengDepartment of Medical Research, Chi-Mei Medical Center, Yongkang Dist., Tainan City71004, TaiwanTel +886 6 251 7864Email
| | - Ming Chang Wu
- Department of Food Science, College of Agriculture, National Pingtung University of Science and Technology, Pingtung91201, Taiwan
- Ming Chang WuDepartment of Food Science, College of Agriculture, National Pingtung University of Science and Technology, Neipu91201, Pingtung, TaiwanTel +886 8 770 3202Email
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Ateyya H, Nader MA, El-Sherbeeny NA. Beneficial effects of rosiglitazone and losartan combination in diabetic rats. Can J Physiol Pharmacol 2018; 96:215-220. [DOI: 10.1139/cjpp-2017-0332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Diabetes with vascular complication needs strict interventions to retard possible serious complications. This research estimated the possible interaction of rosiglitazone (RGN) with losartan (Los) in diabetic rats. Male Sprague–Dawley rats were randomly divided into nondiabetic rats, diabetic rats, and diabetic rats that received RGN, Los, or a combination of RGN and Los. Measurement of serum glucose, vascular adhesion molecule-1, interleukin-6, tumor necrosis factor-α, aortic lipid peroxide (malondialdehyde), glutathione, superoxide dismutase, and total nitrate/nitrite levels was done. Also, the effects of RGN on the relaxation created by acetylcholine and sodium nitroprusside, contraction of isolated aortic rings provoked by phenylephrine and angiotensin II were determined. Results revealed that RGN or Los had a vasodilating effect to variable degrees indicated by enhanced effects on both acetylcholine-induced relaxation and the antagonistic effect on angiotensin II and phenylephrine-stimulated contraction of diabetic aortas with significant amelioration in serum glucose, vascular adhesion molecule-1, interleukin-6, and tumor necrosis factor-α levels and aortic oxidant/antioxidant balance. Treatment of diabetic rats with a combination of RGN and Los produced a more pronounced effect on the measured parameters compared to the diabetic, RGN-, and Los-treated groups. These findings point out the beneficial effects of RGN and Los combination in diabetic rats.
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Affiliation(s)
- Hayam Ateyya
- College of Pharmacy, Taibah University, El-Madinah El-Munawarah, Saudi Arabia
- Department of Clinical Pharmacology, Faculty of Medicine, Cairo University, Egypt
| | - Manar A. Nader
- College of Pharmacy, Taibah University, El-Madinah El-Munawarah, Saudi Arabia
- Faculty of Pharmacy, Mansoura University, Egypt
| | - Nagla A. El-Sherbeeny
- College of Pharmacy, Taibah University, El-Madinah El-Munawarah, Saudi Arabia
- Department of Clinical Pharmacology, Faculty of Medicine, Suez Canal University, Egypt
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Chao PC, Li Y, Chang CH, Shieh JP, Cheng JT, Cheng KC. Investigation of insulin resistance in the popularly used four rat models of type-2 diabetes. Biomed Pharmacother 2018; 101:155-161. [PMID: 29486333 DOI: 10.1016/j.biopha.2018.02.084] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 02/07/2018] [Accepted: 02/19/2018] [Indexed: 12/12/2022] Open
Abstract
Animal models are widely used to develop drugs for treating diabetes mellitus (DM). Insulin resistance (IR) is one of the main problems in type-2 DM (T2DM). Streptozotocin (STZ) is used to damage pancreatic cells for induction of DM. Many rat models were applied in research as T2DM. However, the degree of IR in each model is unknown. In the present study, IR and insulin signaling were compared in four models of type 2 diabetes: rats fed a fructose-rich chow for 8 weeks, rats feed high-fat chow for 4 weeks followed by injection with streptozotocin (35 mg/kg, i.p.), rats injected with a single low dose streptozotocin (45 mg/kg, i.p.), and rats injected with a single dose of nicotinamide followed by a single high dose of streptozotocin (60 mg/kg, i.p.). Values from these determinations in diabetic rats showing the order that insulin resistance is most marked in rats received fructose-rich chow followed by high-fat diet before STZ injection induced model (HFD/STZ rats), and rats injected with low dose of STZ but it is less marked in rats induced by nicotinamide and STZ. Additionally, insulin secretion was reduced in three rat models except the rats receiving fructose-rich chow. Western blots also showed the same changes in phosphorylation of IRS-1 or Akt using soleus muscle from each model. The obtained data suggest a lack of pronounced IR in the rats with acute diabetes induced by nicotinamide and STZ while IR is markedly identified in rats fed fructose-rich chow. However, the increase of plasma glucose levels in fructose-rich chow-fed rats was not so significant as other groups. Therefore, HFD/STZ rats is an appropriate and stable animal model which is analogous to the human T2DM through a combination of high-fat diet with multiple low-dose STZ injections.
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Affiliation(s)
- Pin-Chun Chao
- Bachelor Program of Senior Services, College of Humanities and Social Sciences, Southern Taiwan University of Science and Technology, Yong Kang, Tainan City, 71005, Taiwan
| | - Yingxiao Li
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, 890-8520, Japan; Department of Medical Research, Chi-Mei Medical Center, Yong Kang, Tainan City, 71003, Taiwan
| | - Chin-Hong Chang
- Department of Neurosurgery, Chi-Mei Medical Center, Yong Kang, Tainan City, 71003, Taiwan
| | - Ja Ping Shieh
- Department of Anesthesiology, Chi-Mei Medical Center, Yong Kang, Tainan City, 71003, Taiwan
| | - Juei-Tang Cheng
- Department of Medical Research, Chi-Mei Medical Center, Yong Kang, Tainan City, 71003, Taiwan; Institute of Medical Sciences, Chang Jung Christian University, Gueiren, Tainan City, 71101, Taiwan.
| | - Kai-Chun Cheng
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, 890-8520, Japan.
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lyoussi B, Cherkaoui-Tangi K, Morel N, Wibo M. Characterization of vascular dysregulation in meriones shawi after high-calorie diet feeding. Clin Exp Hypertens 2018; 40:353-362. [DOI: 10.1080/10641963.2017.1377219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Badiaa lyoussi
- Laboratoire de physiologie-pharmacologie et santé environnementale, Faculté des Sciences Dhar-Mahraz, Université Sidi Mohamed Ben Abdallah, POBox 1976 Fès Atlas, Fès, Morocco
| | - khadija Cherkaoui-Tangi
- Laboratoire de physiologie-pharmacologie et santé environnementale, Faculté des Sciences Dhar-Mahraz, Université Sidi Mohamed Ben Abdallah, POBox 1976 Fès Atlas, Fès, Morocco
- Secteur des Sciences de la Santé, Université catholique de Louvain, Bruxelles, Belgium
| | - Nicole Morel
- Secteur des Sciences de la Santé, Université catholique de Louvain, Bruxelles, Belgium
| | - Maurice Wibo
- Secteur des Sciences de la Santé, Université catholique de Louvain, Bruxelles, Belgium
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Beladiya JV, Chaudagar KK, Mehta AA. A protective role of Gαq-RGS2 loop activator on streptozotocin induced diabetic complications in rats: An independent on elevated serum glucose level modulation. Eur J Pharmacol 2018; 818:141-147. [DOI: 10.1016/j.ejphar.2017.10.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 10/16/2017] [Accepted: 10/20/2017] [Indexed: 10/18/2022]
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Mudrovcic N, Arefin S, Van Craenenbroeck AH, Kublickiene K. Endothelial maintenance in health and disease: Importance of sex differences. Pharmacol Res 2017; 119:48-60. [PMID: 28108363 DOI: 10.1016/j.phrs.2017.01.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 02/07/2023]
Abstract
The vascular endothelium has emerged as more than just an inert monolayer of cells lining the vascular bed. It represents the interface between the blood stream and vessel wall, and has a strategic role in regulating vascular homeostasis by the release of vasoactive substances. Endothelial dysfunction contributes to the development and progression of cardiovascular disease. Recognition of sex-specific factors implicated in endothelial cell biology is important for the identification of clinically relevant preventive and/or therapeutic strategies. This review aims to give an overview of the recent advances in understanding the importance of sex specific observations in endothelial maintenance, both in healthy and diseased conditions. The female endothelium is highlighted in the context of polycystic ovary syndrome and pre-eclampsia. Furthermore, sex differences are explored in chronic kidney disease, which is currently appreciated as one of public health priorities. Overall, this review endorses integration of sex analysis in experimental and patient-oriented research in the exciting field of vascular biology.
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Affiliation(s)
- Neja Mudrovcic
- Department of Clinical Science, Intervention & Technology, Division of Obstetrics & Gynecology, Karolinska Institutet, Stockholm, Sweden
| | - Samsul Arefin
- Department of Clinical Science, Intervention & Technology, Division of Obstetrics & Gynecology, Karolinska Institutet, Stockholm, Sweden
| | - Amaryllis H Van Craenenbroeck
- Department of Nephrology, Antwerp University Hospital, Antwerp, Belgium; Laboratory of Experimental Medicine and Pediatrics, University of Antwerp, Antwerp, Belgium; Department of Clinical Science, Intervention & Technology, Division of Renal Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Karolina Kublickiene
- Department of Clinical Science, Intervention & Technology, Division of Obstetrics & Gynecology, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Science, Intervention & Technology, Division of Renal Medicine, Karolinska Institutet, Stockholm, Sweden; Centre for Gender Medicine, Department of Medicine-Solna, Karolinska Institutet, Stockholm, Sweden.
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Rehman AU, Dugic E, Benham C, Lione L, Mackenzie LS. Selective inhibition of NADPH oxidase reverses the over contraction of diabetic rat aorta. Redox Biol 2013; 2:61-4. [PMID: 25460721 PMCID: PMC4297944 DOI: 10.1016/j.redox.2013.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 12/02/2013] [Accepted: 12/04/2013] [Indexed: 11/18/2022] Open
Abstract
Abnormal vascular responsiveness in diabetes has been attributed to a number of changes in contractile pathways, affected in part by the overproduction of reactive oxygen species (ROS). It has been reported that NADPH oxidase (NOX) is increased in diabetic (streptozotocin treated; STZ) rat arteries; however the pharmacological agents used to inhibit NOX activity are known to be unsuitable for in vitro studies and have a high level of non-selectivity. Here we have used the highly selective NOX inhibitor VAS2870 in diabetic rat aorta and compared its effects with apocynin, SOD, and allopurinol on phenylephrine and U46619 induced contraction. Male Wistar rats were injected intraperitoneally with 65mg/kg STZ and development of diabetes was confirmed by testing blood glucose levels. Rats were killed by CO2 asphyxiation, and the thoracic aorta removed and mounted in an organ bath under a tension of 1g. Diabetic rat aortas exhibit a greatly increased response to phenylephrine, which was reduced to a level consistent with control rat aorta by 10(-5)M VAS2870 and 150U/ml SOD. Incubation with VAS2870 led to an increase in normal rat aorta contraction, but led to a significant reduction in phenylephrine and U46619 induced tone in diabetic rat aorta, which indicates that ROS in diabetic rats directly contributes to these contractile responses. Apocynin and allopurinol had no effect on contraction in diabetic or normal rat aorta. This data is the first to show that selective inhibition of NOX reduces diabetic arterial contraction in direct comparison with inhibition of other known contributors of ROS.
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Affiliation(s)
- Atif Ur Rehman
- Biosciences, School of Life and Medical Sciences, University Hertfordshire, College Lane AL10 9AB, UK
| | - Elma Dugic
- Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University, 58185 Linköping, Sweden
| | - Chris Benham
- Biosciences, School of Life and Medical Sciences, University Hertfordshire, College Lane AL10 9AB, UK
| | - Lisa Lione
- Biosciences, School of Life and Medical Sciences, University Hertfordshire, College Lane AL10 9AB, UK
| | - Louise S Mackenzie
- Biosciences, School of Life and Medical Sciences, University Hertfordshire, College Lane AL10 9AB, UK.
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Ali DK, Oriowo M, Tovmasyan A, Batinic-Haberle I, Benov L. Late administration of Mn porphyrin-based SOD mimic enhances diabetic complications. Redox Biol 2013; 1:457-66. [PMID: 24191241 PMCID: PMC3815015 DOI: 10.1016/j.redox.2013.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 09/11/2013] [Accepted: 09/12/2013] [Indexed: 01/12/2023] Open
Abstract
Mn(III) N-alkylpyridylporphyrins (MnPs) have demonstrated protection in various conditions where increased production of reactive oxygen/reactive nitrogen species (ROS/RNS), is a key pathological factors. MnPs can produce both pro-oxidative and antioxidative effects depending upon the cellular redox environment that they encounter. Previously we reported (Free Radic. Res. 39: 81–8, 2005) that when the treatment started at the onset of diabetes, Mn(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin, MnTM-2-PyP5+ suppressed diabetes-induced oxidative stress. Diabetes, however, is rarely diagnosed at its onset. The aim of this study was to investigate if MnTM-2-PyP5+ can suppress oxidative damage and prevent diabetic complications when administered more than a week after the onset of diabetes. Diabetes was induced by streptozotocin. The MnP-based treatment started 8 days after the onset of diabetes and continued for 2 months. The effect of the treatment on activities of glutathione peroxidase, superoxide dismutase, catalase, glutathione reductase, glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and glyoxalases I and II as well as malondialdehyde and GSH/GSSG ratio were determined in kidneys. Kidney function was assessed by measuring lysozyme and total protein in urine and blood urea nitrogen. Vascular damage was evaluated by assessing vascular reactivity. Our data showed that delayed administration of MnTM-2-PyP5+ did not protect against oxidative damage and did not prevent diabetic complications. Moreover, MnTM-2-PyP5+ contributed to the kidney damage, which seems to be a consequence of its pro-oxidative action. Such outcome can be explained by advanced oxidative damage which already existed at the moment the therapy with MnP started. The data support the concept that the overall biological effect of a redox-active MnP is determined by (i) the relative concentrations of oxidants and reductants, i.e. the cellular redox environment and (ii) MnP biodistribution. Mn porphyrins (MnP) are among the most potent SOD mimics. MnP suppressed diabetes-induced oxidative stress if applied at the onset of diabetes. Delayed administration of MnP augmented oxidative stress and diabetic complications. The overall in vivo effect of MnP depends on its redox environment.
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Affiliation(s)
- Dana K. Ali
- Department of Biochemistry, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait
| | - Mabayoje Oriowo
- Department of Pharmacology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait
| | - Artak Tovmasyan
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ines Batinic-Haberle
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
- Correspondence to: Department of Radiation Oncology, Duke University Medical Center, Research Drive, 281b/285, MSRB I, Box 3455, Durham, NC 27710, USA. Tel.: +1 919 684 2101; fax: +1 919 684 8718.
| | - Ludmil Benov
- Department of Biochemistry, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait
- Corresponding author. Tel.: +965 2531 9489; fax: +965 2533 8908.
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Khalili A, Nekooeian AA, Khosravi MB, Fakher S. Simultaneous renal hypertension and type 2 diabetes exacerbate vascular endothelial dysfunction in rats. Int J Exp Pathol 2012; 93:210-7. [PMID: 22458508 DOI: 10.1111/j.1365-2613.2012.00811.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Despite the high rate of occurrence of both diabetes and hypertension in humans, the cardiovascular effects of the two conditions have not been investigated when they occur simultaneously. Thus this study examined the vascular effects of simultaneous type 2 diabetes and renal hypertension on endothelial function. Serum malondialdehyde and systolic blood pressure (SBP) were measured, glucose tolerance test (GTT) was performed, and concentration-response to phenylephrine (PE) in the absence and presence of nitro-l-arginine methyl ester (l-NAME), acetylcholine and sodium nitroprusside were conducted on aortic rings from diabetic control, type 2 diabetes, sham-operated, renal hypertensive, and simultaneous type 2 diabetes plus hypertension rats respectively. Hypertension, diabetes, and simultaneous diabetes and hypertension were associated with either increased or decreased maximal responses (E(max)) of PE dependent on in the presence or absence of l-NAME. There was also increased serum malondialdehyde and decreased E(max) of acetylcholine. Thus simultaneous hypertension and diabetes caused a greater decrease in E(max) of acetylcholine compared to that seen with either diabetes or hypertension alone higher than that seen in hypertension. The blood glucose during GTT was lower than that seen in diabetes groups. Thus simultaneous type 2 diabetes and the SBP was renal hypertension is associated with improved glucose tolerance, but with further deterioration of endothelial dysfunction compared with either condition alone.
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Affiliation(s)
- Azadeh Khalili
- Department of Pharmacology, Cardiovascular Pharmacology Research Center, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
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14
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Félétou M. The Endothelium, Part I: Multiple Functions of the Endothelial Cells -- Focus on Endothelium-Derived Vasoactive Mediators. ACTA ACUST UNITED AC 2011. [DOI: 10.4199/c00031ed1v01y201105isp019] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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15
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16
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Pinho JF, Medeiros MAA, Capettini LSA, Rezende BA, Campos PP, Andrade SP, Cortes SF, Cruz JS, Lemos VS. Phosphatidylinositol 3-kinase-δ up-regulates L-type Ca2+ currents and increases vascular contractility in a mouse model of type 1 diabetes. Br J Pharmacol 2011; 161:1458-71. [PMID: 20942845 DOI: 10.1111/j.1476-5381.2010.00955.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Vasculopathies represent the main cause of morbidity and mortality in diabetes. Vascular malfunctioning in diabetes is associated with abnormal vasoconstriction and Ca(2+) handling by smooth muscle cells (SMC). Phosphatidylinositol 3-kinases (PI3K) are key mediators of insulin action and have been shown to modulate the function of voltage-dependent L-type Ca(2+) channels (Ca(V) 1.2). In the present work, we investigated the involvement of PI3K signalling in regulating Ca(2+) current through Ca(V) 1.2 (I(Ca,L) ) and vascular dysfunction in a mouse model of type I diabetes. EXPERIMENTAL APPROACH Changes in isometric tension were recorded on myograph. Ca(2+) currents in freshly dissociated mice aortic SMCs were measured using the whole-cell patch-clamp technique. Antisense techniques were used to knock-down the PI3Kδ isoform. KEY RESULTS Contractile responses to phenylephrine and KCl were strongly enhanced in diabetic aorta independent of a functional endothelium. The magnitude of phenylephrine-induced I(Ca,L) was also greatly augmented. PI3Kδ expression, but not PI3Kα, PI3Kβ, PI3Kγ, was increased in diabetic aortas and treatment of vessels with a selective PI3Kδ inhibitor normalized I(Ca,L) and contractile response of diabetic vessels. Moreover, knock-down of PI3Kδin vivo decreased PI3Kδ expression and normalized I(Ca,L) and contractile response of diabetic vessels ex vivo. CONCLUSIONS AND IMPLICATIONS Phosphatidylinositol 3-kinase δ was essential to the increased vascular contractile response in our model of type I diabetes. PI3Kδ signalling was up-regulated and most likely accounted for the increased I(Ca,L,) leading to increased vascular contractility. Blockade of PI3Kδ may represent a novel therapeutic approach to treat vascular dysfunction in diabetic patients.
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Affiliation(s)
- J F Pinho
- Department of Physiology and Biophysics, ICB, Federal University of Minas Gerais, Belo Horizonte, Brazil
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Takenouchi Y, Kobayashi T, Taguchi K, Matsumoto T, Kamata K. Relationship among superoxide-related enzyme, PPARs, and endothelium-dependent relaxation in murine aortas previously organ-cultured in high-glucose conditions. Can J Physiol Pharmacol 2010; 88:760-9. [PMID: 20651824 DOI: 10.1139/y10-045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The aim of the present study was to investigate the relationship among superoxide anion, peroxisome proliferator-activated receptors (PPARs), and endothelium-dependent relaxation in murine aortas organ-cultured in a high-glucose condition. Aortas organ-cultured with a high concentration of glucose (40 mmol/L, 20 h; HG group) exhibited the following characteristics (versus aortas cultured in serum-free medium): (i) significantly weaker relaxation to acetylcholine, but unchanged relaxation to SNP and unchanged contractions to norepinephrine and isotonic K+, (ii) significantly greater superoxide generation (indicated by the amount of nitroblue tetrazolium reduced, (iii) significantly higher protein expression levels of gp91phox, NAD(P)H oxidase subunits, and endothelial NO synthase, (iv) significantly lower protein expression level of Mn-superoxide dismutase (SOD), and (v) markedly greater reduction in the protein expression of PPARgamma than in that of PPARalpha. The HG-induced impairment of endothelium-dependent relaxation was prevented by cotreatment with tempol (a SOD mimetic). These results suggest that in the mouse aorta, exposure to high glucose levels may lead to an excessive generation of superoxide via increased gp91phox and decreased Mn-SOD protein expression and that this may in turn trigger an impairment of endothelium-dependent relaxation. Moreover, such protein changes in gp91phox and Mn-SOD may be secondary to a decreased expression of PPARgamma protein.
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Affiliation(s)
- Yasuhiro Takenouchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
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18
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Hong E, Huang F, Villafaña S. Effect of Early Diabetes on the Response to Norepinephrine and Dopamine in Pithed Wistar Kyoto and Spontaneously Hypertensive Rats. Clin Exp Hypertens 2010; 32:390-4. [DOI: 10.3109/10641961003628544] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Takenouchi Y, Kobayashi T, Taguchi K, Matsumoto T, Kamata K. Gender differences in endothelial function in aortas from type 2 diabetic model mice. J Pharmacol Sci 2009; 111:91-9. [PMID: 19721331 DOI: 10.1254/jphs.09133fp] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Type 2 diabetes mellitus is associated with high mortality and morbidity, mainly due to coronary artery disease and atherosclerosis, although female gender is a protective factor in the development of, for example, atherosclerosis and hypertension. Our main aim was to investigate gender differences in endothelial function in aortas from type 2 diabetic model mice. The nonfasting plasma glucose level was significantly elevated in diabetic mice (both males and females). The plasma insulin level was not different between controls and diabetics (either gender). The plasma adiponectin level was decreased by diabetes, and was lower in males. In control aortas (from males or females), the clonidine-induced relaxation was abolished by Akt-inhibitor treatment. In diabetic males (versus both control males and diabetic females): a) the clonidine- and insulin-induced endothelium-dependent aortic relaxations were impaired, but the acetylcholine (ACh)-induced and sodium nitroprusside (SNP)-induced aortic relaxations were not, b) the norepinephrine (NE)-induced aortic contractile response was enhanced, c) systemic blood pressure was elevated, and d) the clonidine-stimulated Ser-473 phosphorylation of Akt in the aorta was decreased. These results suggest that endothelial functions dependent on the Akt pathway are abrogated by type 2 diabetes only in male mice.
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Affiliation(s)
- Yasuhiro Takenouchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Japan
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20
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Sandow SL, Gzik DJ, Lee RMKW. Arterial internal elastic lamina holes: relationship to function? J Anat 2009; 214:258-66. [PMID: 19207987 DOI: 10.1111/j.1469-7580.2008.01020.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Internal elastic lamina (IEL) hole (fenestration) characteristics and myoendothelial gap junction (MEGJ) density were examined in selected resistance and conduit arteries of normal and diseased rat and mouse models, using conventional, ultrastructural and confocal microscopy methods. Selected vessels were those commonly used in functional studies: thoracic aorta, proximal and distal mesenteric, caudal, saphenous, middle-cerebral and caudal cerebellar artery. Rat and mouse strains and treatment groups examined were Dahl, Sprague Dawley, Wistar Kyoto, Wistar, spontaneously hypertensive (SHR), deoxycorticosterone (DOC) treated rat; and apolipoprotein E knockout, C57/BL6 and BALB/c mice. Vessel size (as IEL circumference), IEL hole and MEGJ density were quantified. In mesenteric arteries, the width of IEL holes and the percent of IEL occupied by holes were also determined. IEL hole density varied significantly within and between mesenteric artery beds, even among normotensive rat strains. Among the hypertensive rats (SHR and DOC), hole density in some vessels was higher in the normotensives than in the hypertensives within each strain, whereas in Dahl rats, hole density was similar between hypertensives and normotensives. Hole density was not correlated with the formation of intimal lesions in superior mesenteric artery. There was no positive general correlation between IEL hole and MEGJ density in resistance and conduit vessels. However, there was a positive correlation between the size of some resistance arteries and MEGJ density, although such a relationship did not hold for conduit vessels or during development, and there was no such relationship between vessel size and IEL hole density. Whilst IEL holes are obviously required for MEGJ communication, their presence is not an indication of contact-mediated communication, but rather may be related to the presence of sites for the low resistance passage of diffusion-mediated release of vasoactive endothelial and smooth muscle substances.
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Affiliation(s)
- Shaun L Sandow
- Department of Anesthesia, McMaster University, Hamilton, Ontario, Canada
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Matsumoto T, Noguchi E, Ishida K, Kobayashi T, Yamada N, Kamata K. Metformin normalizes endothelial function by suppressing vasoconstrictor prostanoids in mesenteric arteries from OLETF rats, a model of type 2 diabetes. Am J Physiol Heart Circ Physiol 2008; 295:H1165-H1176. [PMID: 18641273 DOI: 10.1152/ajpheart.00486.2008] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We previously reported that in mesenteric arteries from aged Otsuka Long-Evans Tokushima fatty (OLETF) rats (a type 2 diabetes model) endothelium-derived hyperpolarizing factor (EDHF)-type relaxation is impaired while endothelium-derived contracting factor (EDCF)-mediated contraction is enhanced (Matsumoto T, Kakami M, Noguchi E, Kobayashi T, Kamata K. Am J Physiol Heart Circ Physiol 293: H1480-H1490, 2007). Here we investigated whether acute and/or chronic treatment with metformin might improve this imbalance between the effects of the above endothelium-derived factors in mesenteric arteries isolated from OLETF rats. In acute studies on OLETF mesenteric arteries, ACh-induced relaxation was impaired and the relaxation became weaker at high ACh concentrations. Both metformin and 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside [AICAR, an AMP-activated protein kinase (AMPK) activator that is also activated by metformin] 1) diminished the tendency for the relaxation to reverse at high ACh concentrations and 2) suppressed both ACh-induced EDCF-mediated contraction and ACh-stimulated production of prostanoids (thromboxane A2 and PGE2). In studies on OLETF arteries from chronically treated animals, metformin treatment (300 mg.kg(-1).day(-1) for 4 wk) 1) improved ACh-induced nitric oxide- or EDHF-mediated relaxation and cyclooxygenase (COX)-mediated contraction, 2) reduced EDCF-mediated contraction, 3) suppressed production of prostanoids, and 4) reduced superoxide generation. Metformin did not alter the protein expressions of endothelial nitric oxide synthase (eNOS), phospho-eNOS (Ser1177), or COX-1, but it increased COX-2 protein. These results suggest that metformin improves endothelial functions in OLETF mesenteric arteries by suppressing vasoconstrictor prostanoids and by reducing oxidative stress. Our data suggest that within the timescale studied here, metformin improves endothelial function through this direct mechanism, rather than by improving metabolic abnormalities.
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Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo 142-8501, Japan
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Elmi S, Sallam NA, Rahman MM, Teng X, Hunter AL, Moien-Afshari F, Khazaei M, Granville DJ, Laher I. Sulfaphenazole treatment restores endothelium-dependent vasodilation in diabetic mice. Vascul Pharmacol 2008; 48:1-8. [DOI: 10.1016/j.vph.2007.09.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2007] [Revised: 09/02/2007] [Accepted: 09/06/2007] [Indexed: 02/07/2023]
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Takenouchi Y, Kobayashi T, Matsumoto T, Kamata K. Possible Involvement of Akt Activity in Endothelial Dysfunction in Type 2 Diabetic Mice. J Pharmacol Sci 2008; 106:600-8. [DOI: 10.1254/jphs.fp0071684] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Malakul W, Thirawarapan S, Suvitayavat W, Woodman OL. Type 1 diabetes and hypercholesterolaemia reveal the contribution of endothelium-derived hyperpolarizing factor to endothelium-dependent relaxation of the rat aorta. Clin Exp Pharmacol Physiol 2007; 35:192-200. [PMID: 17941894 DOI: 10.1111/j.1440-1681.2007.04811.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
1. The present study evaluated the effect of diabetes, hypercholesterolaemia and their combination on the contribution of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) to relaxation of rat isolated aortic rings and the potential contribution of oxidant stress to the disturbance of endothelial function. 2. Thoracic aortic rings from control, diabetic, hypercholesterolaemic and diabetic plus hypercholesterolaemic rats were suspended in organ baths for tension recording. Generation of superoxide by the aorta was measured using lucigenin-enhanced chemiluminescence. 3. The maximal response to acetylcholine (ACh) was significantly reduced in diabetic or hypercholesterolaemic rats compared with control rats. In rats with diabetes plus hypercholesterolaemia, both the sensitivity and maximal response to ACh was impaired. In control rats, the response to ACh was abolished by the NO synthase inhibitor N(G)-nitro-L-arginine (L-NNA) or inhibition of soluble guanylate cyclase with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). In contrast, in rats with diabetes, hypercholesterolaemia or both, relaxation to ACh was resistant to inhibition by L-NNA or ODQ, but abolished by additional inhibition of K(Ca) channels with charybdotoxin plus apamin. 4. The generation of superoxide was not significantly enhanced in aortic rings from either diabetic or hypercholesterolaemic rats, but was significantly increased in aortic rings from rats with diabetes plus hypercholesterolaemia. 5. These results suggest that when diabetes and hypercholesterolaemia impair endothelium-dependent relaxation, due to a diminished contribution from NO, a compensatory contribution of EDHF to endothelium-dependent relaxation of the aorta is revealed. The attenuation of NO-mediated relaxation, at least in the presence of both diabetes and hypercholesterolaemia, is associated with enhanced superoxide generation.
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Bender SB, Herrick EK, Lott ND, Klabunde RE. Diet-induced obesity and diabetes reduce coronary responses to nitric oxide due to reduced bioavailability in isolated mouse hearts. Diabetes Obes Metab 2007; 9:688-96. [PMID: 17697061 DOI: 10.1111/j.1463-1326.2006.00650.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM The aim of the present study was to examine nitric oxide (NO)-mediated coronary vascular responses in a mouse model of obesity and diabetes induced by a high-fat, high-carbohydrate diet. We hypothesized that endogenous NO bioavailability would be reduced in obese/diabetic mouse hearts due to enhanced superoxide anion production, and that coronary smooth muscle responses to exogenous NO would be reduced. METHODS Age-matched, male C57BL/6J mice were fed either a control diet or a high-fat, high-carbohydrate diet. After 15 weeks, the mice were anesthetized and their hearts were removed and perfused by the Langendorff method under constant flow conditions with an oxygenated buffer solution, and changes in coronary vascular resistance were quantified. RESULTS Mice fed the high-fat, high-carbohydrate diet became obese, hyperglycaemic and hyperinsulinaemic. Coronary vasoconstrictor responses to NO synthase inhibition by N(omega)-nitro-L-arginine methyl ester were reduced in obese/diabetic mice; normal responses were restored by pretreatment with the superoxide dismutase mimetic 2,2,6,6-tetramethyl-1-piperidinyloxy (Tempol). Coronary endothelium-independent vasodilation to the NO donor (+/-)-S-nitroso-N-acetylpenicillamine (SNAP) was reduced; however, 8-bromo-cyclic guanosine monophosphate (cGMP)-induced vasodilation was unchanged in obese/diabetic hearts. CONCLUSIONS These findings suggest that in a diet-induced mouse model of obesity and diabetes, NO bioavailability is reduced by increased superoxide NO scavenging leading to impaired NO-mediated vasodilation. Furthermore, the attenuation of SNAP-induced vasodilation may be due to increased reactive oxygen species scavenging of exogenous NO because normal vascular smooth muscle NO signalling is maintained as indicated by similar 8-bromo-cGMP responses in control and obese/diabetic hearts.
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Affiliation(s)
- S B Bender
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH 45701, USA
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Seto SW, Lam TY, Leung GPH, Au ALS, Ngai SM, Chan SW, Kwan YW. Comparison of vascular relaxation, lipolysis and glucose uptake by peroxisome proliferator-activated receptor-gamma activation in +db/+m and +db/+db mice. Eur J Pharmacol 2007; 572:40-8. [PMID: 17603034 DOI: 10.1016/j.ejphar.2007.05.070] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 05/22/2007] [Accepted: 05/23/2007] [Indexed: 11/21/2022]
Abstract
In this study, we determined the in vitro effect of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) activation on the aortic relaxation, lipolysis and insulin-induced [(3)H]-glucose uptake of the abdominal (omental) adipocytes of the non-diabetic (+db/+m) and obese/diabetic (+db/+db) mice. The expression of PPAR-gamma (mRNA and protein) in aorta and adipose tissues was evaluated and compared. Cumulative application of ciglitazone, pioglitazone and troglitazone (PPAR-gamma agonists) caused a concentration-dependent aortic relaxation (sensitive to 2-chloro-5-nitro-N-phenylbenzamide (GW9662) (1 microM, a selective PPAR-gamma antagonist) and N(omega)-nitro-l-arginine methyl ester (l-NAME) (20 microM, a nitric oxide synthase inhibitor)) with a maximum relaxation of approximately 30% (3 microM) in +db/+m mice, whereas no relaxation was observed in +db/+db mice. All PPAR-gamma agonists examined did not alter the basal lipolysis of both species, but forskolin caused a concentration-dependent lipolysis, with a greater magnitude observed in +db/+m mice. Insulin (0.1 and 1 microM) caused an enhancement of [(3)H]-glucose uptake into adipocytes with a greater magnitude in +db/+m mice. In contrast, none of the PPAR-gamma agonists tested (0.1, 1 and 10 microM) altered the basal and the insulin (0.1 microM)-induced [(3)H]-glucose uptake into adipocytes of both species. In addition, there was no difference in PPAR-gamma expression (mRNA and protein) in the aorta and adipose tissues between the species. In conclusion, our results demonstrate that PPAR-gamma is present in the abdominal (omental) adipose tissue and thoracic aorta. An acute activation of PPAR-gamma produced a small ( approximately 30%) aortic relaxation (nitric oxide/endothelium-dependent) of +db/+m mice. However, all PPAR-gamma agonists examined have no acute effect on lipolysis and the insulin-induced glucose uptake into adipocytes of both +db/+m and +db/+db mice.
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MESH Headings
- Abdominal Fat/metabolism
- Adipocytes/drug effects
- Adipocytes/metabolism
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiopathology
- Carbohydrate Metabolism/drug effects
- Chromans/pharmacology
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/physiopathology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiopathology
- Female
- Glucose/metabolism
- Hypoglycemic Agents/pharmacology
- In Vitro Techniques
- Insulin/pharmacology
- Lipid Metabolism
- Lipolysis/drug effects
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Obesity/metabolism
- Obesity/physiopathology
- PPAR gamma/agonists
- PPAR gamma/biosynthesis
- Pioglitazone
- RNA, Messenger/agonists
- RNA, Messenger/biosynthesis
- Thiazolidinediones/pharmacology
- Troglitazone
- Vasodilation/drug effects
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Affiliation(s)
- Sai Wang Seto
- Department of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong
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Matsumoto T, Kobayashi T, Kamata K. Mechanisms underlying lysophosphatidylcholine-induced potentiation of vascular contractions in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat aorta. Br J Pharmacol 2006; 149:931-41. [PMID: 17031383 PMCID: PMC2014696 DOI: 10.1038/sj.bjp.0706937] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE The effect of lysophosphatidylcholine (LPC) on aortic contractions in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a type 2 diabetic model, was studied. EXPERIMENTAL APPROACH Using OLETF rats and control (Long Evans Tokushima Otsuka (LETO)) rats, the effects of LPC on the contractions induced by high-K(+) (10-40 mM), UK14,304 (10 approximately 100 nM; a selective alpha(2)-adrenoceptor agonist) and sodium orthovanadate (SOV; 10 microM approximately 3 mM) in endothelium-denuded aortae were compared. Aortic ERK activity and the mRNA expression for GPR4 (a putative LPC receptor) were also measured. KEY RESULTS OLETF rats exhibited (vs. age-matched LETO rats): (1) greater potentiation of high-K(+)-induced contraction by 10 microM LPC - a potentiation attenuated by 10 microM genistein, protein tyrosine kinase (PTK) inhibitor, (2) greater potentiation of UK14,304 (10 approximately 100 nM)-induced contractions by LPC (1 microM approximately 10 microM) - a potentiation attenuated by 10 microM genistein, 50 microM tyrphostin A23 (PTK inhibitor) or 10 microM PD98059 (MEK 1/2 inhibitor), (3) greater basal and LPC (1 microM)-induced ERK activities, (4) greater basal and 100 nM UK14,304-stimulated ERK2 activities in both the absence and presence of 10 microM LPC, (5) greater SOV (10 microM approximately 3 mM)-induced contractions, (6) greater potentiation of SOV-induced contractions by 10 microM LPC - a potentiation suppressed by 10 microM PD98059 or 10 microM genistein, (7) upregulation of GPR4 mRNA. CONCLUSIONS AND IMPLICATIONS These results suggest that the LPC-induced potentiation of contractions in the OLETF rat aorta may be attributable to increased PTKs or ERK activity and/or to receptor upregulation.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Brimonidine Tartrate
- Diabetes Mellitus, Type 2/physiopathology
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Lysophosphatidylcholines/pharmacology
- MAP Kinase Signaling System/drug effects
- Male
- Muscle, Smooth, Vascular/chemistry
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiopathology
- Potassium/pharmacology
- Protein Kinase Inhibitors/pharmacology
- Protein Tyrosine Phosphatases/antagonists & inhibitors
- Quinoxalines/pharmacology
- RNA, Messenger/analysis
- Rats
- Rats, Inbred OLETF
- Rats, Long-Evans
- Receptors, G-Protein-Coupled/analysis
- Up-Regulation
- Vanadates
- Vasoconstriction/drug effects
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- T Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University Shinagawa-ku, Tokyo, Japan
| | - T Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University Shinagawa-ku, Tokyo, Japan
| | - K Kamata
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University Shinagawa-ku, Tokyo, Japan
- Author for correspondence:
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29
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Witting PK, Harris HH, Rayner BS, Aitken JB, Dillon CT, Stocker R, Lai B, Cai Z, Lay PA. The Endothelium-Derived Hyperpolarizing Factor, H2O2, Promotes Metal-Ion Efflux in Aortic Endothelial Cells: Elemental Mapping by a Hard X-ray Microprobe. Biochemistry 2006; 45:12500-9. [PMID: 17029405 DOI: 10.1021/bi0604375] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydrogen peroxide (H(2)O(2)) is a physiologic oxidant implicated in vascular cell signaling, although little is known about the biochemical consequences of its reaction with endothelial cells. Submicrometer-resolution hard X-ray elemental mapping of cultured porcine aortic endothelial cells (PAEC) has provided data on the global changes for intracellular elemental density within PAEC and indicates an efflux of metal ions and phosphorus from the cytoplasm after H(2)O(2) treatment. The synchrotron-radiation-induced X-ray emission experiments (SRIXE) show that H(2)O(2)-treated cells are irregularly shaped and exhibit blebbing indicative of increased permeability due to the damaged membrane. The SRIXE results suggest that H(2)O(2)-induced damage is largely restricted to the cell membrane as judged by the changes to membrane and cytoplasmic components rather than the cell nucleus. The SRIXE data also provide a mechanism for cell detoxification as the metal-ion efflux resulting from the initial H(2)O(2)-mediated changes to cell membrane potentially limits intracellular metal-mediated redox processes through Fenton-like chemistry. They may also explain the increased levels of these ions in atherosclerotic plaques, regardless of whether they are involved in plaque formation. Finally, the SRIXE data support the notion that cultured endothelial cells exposed to H(2)O(2) respond with enhanced cellular metal-ion efflux into the extracellular space.
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Affiliation(s)
- Paul K Witting
- Vascular Biology Group, ANZAC Research Institute, Hospital Road, Concord Repatriation General Hospital, Concord, NSW 2139, Australia
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30
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Lam TY, Seto SW, Lau YM, Au LS, Kwan YW, Ngai SM, Tsui KW. Impairment of the vascular relaxation and differential expression of caveolin-1 of the aorta of diabetic +db/+db mice. Eur J Pharmacol 2006; 546:134-41. [PMID: 16904102 DOI: 10.1016/j.ejphar.2006.07.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Revised: 06/19/2006] [Accepted: 07/04/2006] [Indexed: 02/07/2023]
Abstract
In this study, we compared the endothelium-dependent and -independent relaxation of the isolated thoracic aorta of control (+db/+m) and diabetic (+db/+db) (C57BL/KsJ) mice. The gene expression (mRNA and protein) level of the muscarinic M(3) receptors, endothelial nitric oxide synthase (eNOS) and caveolin-1 of the aorta was also evaluated. Acetylcholine caused a concentration-dependent, N(G)-nitro-L-arginine methyl-ester (20 microM)-sensitive relaxation, with approximately 100% relaxation at 10 microM, in +db/+m mice. In +db/+db mice, the acetylcholine-induced relaxation was significantly smaller (maximum relaxation: approximately 80%). The sodium nitroprusside-mediated relaxation was slightly diminished in +db/+db mice, compared to +db/+m mice. However, there was no significant difference in the isoprenaline- and cromakalim-induced relaxation observed in both species. The mRNA and protein expression levels of caveolin-1 were significantly higher in the aorta of +db/+db mice. In contrast, there was no difference in the mRNA and protein expression levels of eNOS and muscarinic M(3) receptors between these mice. Our results demonstrate that the impairment of the acetylcholine-induced, endothelium-dependent aortic relaxation observed in +db/+db mice was probably associated with an enhanced expression of caveolin-1 mRNA and protein.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Aorta, Thoracic/chemistry
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiopathology
- Blood Glucose/metabolism
- Blotting, Western
- Caveolin 1/analysis
- Cromakalim/pharmacology
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/physiopathology
- Dose-Response Relationship, Drug
- Endothelium, Vascular/physiopathology
- Enzyme Inhibitors/pharmacology
- Female
- Insulin/blood
- Isoproterenol/pharmacology
- Mice
- Mice, Inbred C57BL
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide Synthase Type II/analysis
- Nitric Oxide Synthase Type III
- Nitroprusside/pharmacology
- RNA, Messenger/analysis
- Receptor, Muscarinic M3/analysis
- Vasodilation/drug effects
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Tze Yan Lam
- Department of Pharmacology, The Chinese University of Hong Kong, Hong Kong SAR, PR China
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31
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Andrews KL, Pannirselvam M, Anderson TJ, Jenkins AJ, Triggle CR, Hill MA. The vascular endothelium in diabetes: a practical target for drug treatment? Expert Opin Ther Targets 2006; 9:101-17. [PMID: 15757485 DOI: 10.1517/14728222.9.1.101] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Vascular disease remains a major cause of morbidity and mortality in diabetes mellitus, in spite of recent improvements in outcome, some of which may be modulated by improved endothelial function. Therapeutic strategies aimed directly at preventing, or minimising the extent of, these sequelae are required as an adjunct to treatments directed at normalising the metabolic milieu. The microvasculature, and the endothelium in particular, are early contributors to vascular dysfunction, thus raising the question as to how best to specifically target the endothelium. However, the expansive nature of the microvasculature, the varying demands that tissues have in terms of blood flow, and the heterogeneity that exists amongst cell types in different sites raises potential problems as to the practicality of such an approach. Further-more, temporal and genetic factors in the genesis of diabetic microvascular dysfunction may impact on therapeutic strategies. It is suggested that a systematic approach is required to understand the heterogeneity of the microvasculature, with particular emphasis on relating differences in gene and protein expression with functional properties. Such an approach may then provide the necessary information to allow exploitation of endothelial cell heterogeneity for unique targeted interventions, as well as providing the necessary rationale for pharmacological interventions (both prophylactic and corrective) aimed at the endothelium as a whole.
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Affiliation(s)
- Karen L Andrews
- RMIT University, Microvascular Biology Group, School of Medical Sciences, Bundoora, Victoria 3083, Australia.
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32
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Matsumoto T, Kobayashi T, Kamata K. Mechanisms underlying the impaired EDHF-type relaxation response in mesenteric arteries from Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Eur J Pharmacol 2006; 538:132-40. [PMID: 16678154 DOI: 10.1016/j.ejphar.2006.04.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 03/02/2006] [Accepted: 04/03/2006] [Indexed: 12/30/2022]
Abstract
We previously reported that in mesenteric arteries from streptozotocin-induced diabetic rats, the endothelium-derived hyperpolarizing factor (EDHF)-type relaxation is impaired, possibly due to a reduced action of cAMP. Here, we observed an impairment of acetylcholine-induced EDHF-type relaxation in mesenteric arteries from a type 2 diabetic model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats [vs. age-matched control Long-Evans Tokushima Otsuka (LETO) rats], and we investigated the mechanism underlying this impairment. In the LETO group, this EDHF-type relaxation was attenuated by 18alpha-glycyrrhetinic acid (a gap-junction inhibitor) and by a protein kinase A (PKA) inhibitor. In both groups (OLETF and LETO), it was enhanced by 3-isobutyl-1-methylxanthine, a cAMP-phosphodiesterase (PDE) inhibitor, but following these enhancements it was still weaker in OLETF rats than in LETO rats. The relaxations induced by cilostamide (a selective PDE3 inhibitor) and 8-bromo-cAMP (a cell-permeant cAMP analog) were reduced in OLETF rats, as was PKA activity. The relaxations induced by two activators of Ca(2+)-activated K(+) channels (K(Ca)) [1-ethyl-2-benzimidazolinone (1-EBIO), intermediate-conductance K(Ca) channel (IK(Ca)) activator, and riluzole, small-conductance K(Ca) channel (SK(Ca)) activator] were also impaired in OLETF rats. We conclude that the impairment of EDHF-type relaxation seen in OLETF rats may be attributable not only to a reduction in cAMP/PKA signaling, but also to reduced endothelial K(Ca) channel activities.
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Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
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33
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Kamata K, Makino A, Kanie N, Oda SI, Matsumoto T, Kobayashi T, Kikuchi T, Nishimura M, Honda T. Effects of anthocyanidin derivative (HK-008) on relaxation in rat perfused mesenterial bed. J Smooth Muscle Res 2006; 42:75-88. [PMID: 17001114 DOI: 10.1540/jsmr.42.75] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Anthocyanins, which are responsible for a variety of bright colors (including red, blue, and purple) in fruits, vegetables, and flowers, are consumed as dietary polyphenols. Anthocyanin-containing fruits are thought to decrease coronary heart disease and are used in anti-diabetic preparations. Diabetes is associated with a variety of cardiovascular complications that may be mediated by endothelial dysfunction, and so this study was designed mainly to characterize the influence of a synthesized anthocyanidin derivative (HK-008) over acetylcholine (ACh)-induced relaxation in mesenteric arterial beds isolated from rats. In a glucose-tolerance test in intact rats, HK-008 (30 mg/kg) reduced the glucose level as effectively as the same dose of glibenclamide. The aortic relaxation induced by pinacidil (an ATP-sensitive potassium channel opener) was greatly inhibited by glibenclamide (10 microM), and also significantly inhibited by HK-008 (10 microM). Interestingly, the ACh-induced relaxation in the perfused, preconstricted mesenteric arterial bed was significantly enhanced by HK-008 (10 microM), and this enhancement was significantly attenuated by indomethacin (10 microM). The ACh-induced mesenteric relaxation was impaired by an increase in oxidative stress, viz. superoxide-generating treatment [xanthine oxidase (XO; 0.1 U/ml) plus hypoxanthine (HX; 10 microM)]. However, this impairment was strongly suppressed by HK-008 (10 microM). These results suggest that HK-008 increases endothelium-induced relaxation by suppressing oxidative stress or modulating prostanoids signaling. This compound may therefore be useful against certain cardiovascular disorders.
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Affiliation(s)
- Katsuo Kamata
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Ebara 2-4-41, Shinagawa-ku, Tokyo 142-8501, Japan.
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34
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Matsumoto T, Kobayashi T, Kikuchi T, Honda T, Kamata K. Effects of dual-action genistein derivatives on relaxation in rat aorta. J Smooth Muscle Res 2005; 41:23-33. [PMID: 15855737 DOI: 10.1540/jsmr.41.23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Protein tyrosine kinases and nitric oxide (NO) play important roles in several cardiovascular diseases. In this study, we examined the actions of two compounds, each has structure of genistein (a tyrosine kinase inhibitor) and an NO donor, on endothelium-independent relaxation responses in the isolated rat aorta. By rational drug design, genistein was modified to acquire an NO donor, and we synthesized two such compounds (G-II, G-VI). These compounds and genistein induced dose-dependent relaxation responses in endothelium-denuded aortic strips, the rank order of potencies being G-VI > G-II > genistein. Incubation of endothelium-denuded strips with 1H-[1,2,4] oxadiazolo[4,3-a]-quinoxalin-1-one (ODQ, 10 microM), a guanylyl cyclase inhibitor, inhibited both the G-II- and G-VI-induced relaxations, but not the genistein-induced relaxation. The residual relaxations induced by these two compounds were similar to the genistein-induced relaxation. Incubation of endothelium-denuded strips with lysophosphatidylcholine (LPC, 20 microM)-which is a major atherogenic lysophospholipid component of oxidized low-density lipoprotein and is known to activate tyrosine kinase-caused a significant rightward shift in the dose-response curve for genistein. LPC also shifted the G-II- and G-VI-induced relaxation curves to the right; however, these relaxations in the presence of LPC were greater than that induced by genistein. The sodium nitroprusside-induced relaxation in endothelium-denuded strips was similar between in the absence and presence of LPC. These results suggest that each of our newly developed G-II and G-VI compounds has a dual action, as an NO donor and a tyrosine kinase inhibitor. These compounds may be useful against certain cardiovascular diseases.
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Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan
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35
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Fitzgerald SM, Kemp-Harper BK, Tare M, Parkington HC. ROLE OF ENDOTHELIUM-DERIVED HYPERPOLARIZING FACTOR IN ENDOTHELIAL DYSFUNCTION DURING DIABETES. Clin Exp Pharmacol Physiol 2005; 32:482-7. [PMID: 15854163 DOI: 10.1111/j.1440-1681.2005.04216.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. Under normal conditions, the endothelium plays a major role in the maintenance of vasodilatory tone via the production of endothelium-derived vasodilator agents, such as prostacyclin, nitric oxide and endothelium-derived hyperpolarizing factor (EDHF). Inhibition of endothelium-dependent relaxation features prominently in a range of cardiovascular diseases, including hypertension, coronary artery disease and diabetes. 2. Endothelium-derived hyperpolarizing factor is a prominent vasodilator, particularly in smaller arteries and arterioles. There is now emerging evidence to suggest that EDHF may play a role in the endothelial dysfunction in diabetes. 3. Since the first description of endothelium-dependent hyperpolarization some 20 years ago, it has emerged that EDHF is heterogeneous in nature, consisting of diffusible factors and contact-mediated mechanisms. The specific identity of EDHF in any particular vascular bed may influence the impact of diabetes on vascular function. 4. There is accumulating evidence in diabetic rat models and humans showing impaired EDHF activity in small resistance vessels. In contrast, studies in mice suggest that EDHF activity is actually enhanced under diabetic conditions. 5. It is clear that alterations in EDHF activity may have an important contribution in diabetes, more specifically in contributing to microvascular complications observed under diabetic conditions.
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Affiliation(s)
- Sharyn M Fitzgerald
- Department of Physiology, Monash University, Melbourne, Victoria, Australia.
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36
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Kobayashi T, Matsumoto T, Kamata K. The PI3-K/Akt pathway: roles related to alterations in vasomotor responses in diabetic models. J Smooth Muscle Res 2005; 41:283-302. [PMID: 16557003 DOI: 10.1540/jsmr.41.283] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Macro- and microvascular disease states currently represent the principal causes of morbidity and mortality in patients with type I or type II diabetes mellitus. Abnormal vasomotor responses and impaired endothelium-dependent vasodilation have been demonstrated in various beds in different animal models of diabetes and in humans with type I or type II diabetes. Several mechanisms leading to endothelial dysfunction have been reported, including changes in substrate avail ability, impaired release of NO, and increased destruction of NO. The principal mediators of diabetes-associated endothelial dysfunction are (a) increases in oxidized low density lipoprotein, endothelin-1, angiotensin II, oxidative stress, and (b) decreases in the actions of insulin or growth factors in endothelial cells. An accumulating body of evidence indicates that abnormal regulation of the phosphatidylinositol 3-kinase (PI3-K)/Akt pathway may be one of several factors contributing to vascular dysfunction in diabetes. The PI3-K pathway, which activates serine/threonine protein kinase Akt, enhances NO synthase phosphorylation and NO production. Several studies suggest that in diabetes the relative ineffectiveness of insulin and the hyperglycemia act together to reduce activity in the insulin-receptor substrates (IRS)/PI3-K/Akt pathway, resulting in impairments of both IRS/PI3-K/Akt-mediated endothelial function and NO production. This article summarizes the PI3-K/Akt pathway-mediated contraction and relaxation responses induced by various agents in the blood vessels of diabetic animals.
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Affiliation(s)
- Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan.
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37
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Kobayashi T, Taguchi K, Yasuhiro T, Matsumoto T, Kamata K. Impairment of PI3-K/Akt Pathway Underlies Attenuated Endothelial Function in Aorta of Type 2 Diabetic Mouse Model. Hypertension 2004; 44:956-62. [PMID: 15505117 DOI: 10.1161/01.hyp.0000147559.10261.a7] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The phosphatidylinositol 3-kinase (PI3-K) pathway, which activates serine/threonine protein kinase Akt, enhances endothelial nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production. We investigated the involvement of the PI3-K/Akt pathway in the relaxation responses to acetylcholine (ACh) and clonidine in a new type 2 diabetic model (streptozotocin plus nicotinamide-induced diabetic mice). Plasma glucose and insulin levels were significantly elevated in our model, and intravenous glucose tolerance tests revealed clear abnormalities in glucose tolerance and insulin responsiveness. Although in our model the ACh-induced relaxation and NO
x
−
(NO
2
−
+NO
3
−
)/cGMP production were unchanged, the clonidine-induced and insulin-induced relaxations and NO
x
−
/cGMP production were all greatly attenuated. In control mice, the clonidine-induced and insulin-induced relaxations were each abolished by LY294002 and by Wortmannin (inhibitors of PI3-K), and also by Akt-inhibitor treatment. The ACh-induced relaxation was unaffected by such treatments in either group of mice. The expression level of total Akt protein was significantly decreased in the diabetic mice aorta, but those for the p85 and p110γ subunits of PI3-K were not. The clonidine-induced Ser-473 phosphorylation of Akt through PI3-K was significantly decreased in our model; however, that induced by ACh was not. These results suggest that relaxation responses and NO production mediated via the PI3-K/Akt pathway are decreased in this type 2 diabetic model. This may be a major cause of endothelial dysfunction (and the resulting hypertension) in type 2 diabetes.
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Affiliation(s)
- Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
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