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Sena C, Pereira A, Queiroz M, Palmeira C, Seiça R. Berberine ameliorates endothelial dysfunction in metabolic syndrome. Atherosclerosis 2021. [DOI: 10.1016/j.atherosclerosis.2021.06.294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sena C, Carvalho D, Pereira A, Queiroz M, Seiça R. Beneficial effects of pyridoxamine in endothelial dysfunction of type 2 diabetic animal models. Atherosclerosis 2021. [DOI: 10.1016/j.atherosclerosis.2021.06.293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Azul L, Queiroz M, Leandro A, Seiça R, Sena C. Tackle inflammation associated with endothelial dysfunction in type 2 diabetes: Role of perivascular adipose tissue. Atherosclerosis 2020. [DOI: 10.1016/j.atherosclerosis.2020.10.418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Azul L, Queiroz M, Leandro A, Seiça R, Sena C. Contribution of perivascular adipose tissue to vascular dysfunction in obesity. Atherosclerosis 2020. [DOI: 10.1016/j.atherosclerosis.2020.10.389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pinho A, Fortuna A, Falcão A, Santos A, Seiça R, Estevens C, Veiga F, Ribeiro A. Comparison of ELISA and HPLC-MS methods for the determination of exenatide in biological and biotechnology-based formulation matrices. J Pharm Anal 2019; 9:143-155. [PMID: 31297291 PMCID: PMC6598173 DOI: 10.1016/j.jpha.2019.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/13/2019] [Accepted: 02/10/2019] [Indexed: 12/15/2022] Open
Abstract
The development of biotechnology-based active pharmaceutical ingredients, such as GLP-1 analogs, brought changes in type 2 diabetes treatment options. For better therapeutic efficiency, these active pharmaceutical ingredients require appropriate administration, without the development of adverse effects or toxicity. Therefore, it is required to develop several quantification methods for GLP-1 analogs products, in order to achieve the therapeutic goals, among which ELISA and HPLC arise. These methods are developed, optimized and validated in order to determine GLP-1 analogs, not only in final formulation of the active pharmaceutical ingredient, but also during preclinical and clinical trials assessment. This review highlights the role of ELISA and HPLC methods that have been used during the assessment for GLP-1 analogs, especially for exenatide.
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Affiliation(s)
- A.R. Pinho
- Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - A. Fortuna
- Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- CNC – Centre for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - A. Falcão
- Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- CNC – Centre for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - A.C. Santos
- Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- REQUIMTE/LAQV, Group of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - R. Seiça
- Laboratory of Physiology, IBILI, Faculty of Medicine, University of Coimbra, Pólo das Ciênicas da Saúde, Azinhaga de Sante Comba, 300-548 Coimbra, Portugal
| | - C. Estevens
- Pharmaceutical Development, TECNIMEDE, S. A. Quinta da Cerca, Caixaria, 2565-187 Dois Portos, Portugal
| | - F. Veiga
- Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- REQUIMTE/LAQV, Group of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - A.J. Ribeiro
- Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- I3S, Instituto de Investigação e Inovação em Saúde, Group Genetics of Cognitive Dysfunction, IBMC – Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
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Domingues C, Matafome P, Neves S, Laranjo M, Seiça R, Botelho M, Sarmento-Ribeiro A, Dourado M. PO-104: Everolimus in oral cancer: a potential therapeutic approach dependent on cell type? Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)30238-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Candeias E, Duarte AI, Sebastião I, Fernandes MA, Plácido AI, Carvalho C, Correia S, Santos RX, Seiça R, Santos MS, Oliveira CR, Moreira PI. Middle-Aged Diabetic Females and Males Present Distinct Susceptibility to Alzheimer Disease-like Pathology. Mol Neurobiol 2016; 54:6471-6489. [PMID: 27730513 DOI: 10.1007/s12035-016-0155-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/22/2016] [Indexed: 02/06/2023]
Abstract
Type 2 diabetes (T2D) is a highly concerning public health problem of the twenty-first century. Currently, it is estimated that T2D affects 422 million people worldwide with a rapidly increasing prevalence. During the past two decades, T2D has been widely shown to have a major impact in the brain. This, together with the cognitive decline and increased risk for dementia upon T2D, may arise from the complex interaction between normal brain aging and central insulin signaling dysfunction. Among the several features shared between T2D and some neurodegenerative disorders (e.g., Alzheimer disease (AD)), the impairment of insulin signaling may be a key link. However, these may also involve changes in sex hormones' function and metabolism, ultimately contributing to the different susceptibilities between females and males to some pathologies. For example, female sex has been pointed as a risk factor for AD, particularly after menopause. However, less is known on the underlying molecular mechanisms or even if these changes start during middle-age (perimenopause). From the above, we hypothesized that sex differentially affects hormone-mediated intracellular signaling pathways in T2D brain, ultimately modulating the risk for neurodegenerative conditions. We aimed to evaluate sex-associated alterations in estrogen/insulin-like growth factor-1 (IGF-1)/insulin-related signaling, oxidative stress markers, and AD-like hallmarks in middle-aged control and T2D rat brain cortices. We used brain cortices homogenates obtained from middle-aged (8-month-old) control Wistar and non-obese, spontaneously T2D Goto-Kakizaki (GK) male and female rats. Peripheral characterization of the animal models was done by standard biochemical analyses of blood, plasma, or serum. Steroid sex hormones, oxidative stress markers, and AD-like hallmarks were given by specific ELISA kits and colorimetric techniques, whereas the levels of intracellular signaling proteins were determined by Western blotting. Albeit the high levels of plasma estradiol and progesterone observed in middle-aged control females suggested that they were still under their reproductive phase, some gonadal dysfunction might be already occurring in T2D ones, hence, anticipating their menopause. Moreover, the higher blood and lower brain cholesterol levels in female rats suggested that its dysfunctional uptake into the brain cortex may also hamper peripheral estrogen uptake and/or its local brain steroidogenic metabolism. Despite the massive drop in IGF-1 levels in females' brains, particularly upon T2D, they might have developed some compensatory mechanisms towards the maintenance of estrogen, IGF-1, and insulin receptors function and of the subsequent Akt- and ERK1/2-mediated signaling. These may ultimately delay the deleterious AD-like brain changes (including oxidative damage to lipids and DNA, amyloidogenic processing of amyloid precursor protein and increased tau protein phosphorylation) associated with T2D and/or age (reproductive senescence) in female rats. By demonstrating that differential sex steroid hormone profiles/action may play a pivotal role in brain over T2D progression, the present study reinforces the need to establish sex-specific preventive and/or therapeutic approaches and an appropriate time window for the efficient treatment against T2D and AD.
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Affiliation(s)
- E Candeias
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal
| | - A I Duarte
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal.
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal.
| | - I Sebastião
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
| | - M A Fernandes
- Life Sciences Department, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal
- Instituto do Mar, Life Sciences Department, University of Coimbra, 3004-517, Coimbra, Portugal
| | - A I Plácido
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal
| | - C Carvalho
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal
| | - S Correia
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal
| | - R X Santos
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Life Sciences Department, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal
| | - R Seiça
- Institute of Physiology, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal
| | - M S Santos
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Instituto do Mar, Life Sciences Department, University of Coimbra, 3004-517, Coimbra, Portugal
| | - C R Oliveira
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal
- Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal
| | - P I Moreira
- CNC- Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal.
- Institute of Physiology, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal.
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Sacramento J, Ribeiro M, Rodrigues T, Guarino M, Diogo L, Seiça R, Monteiro E, Matafome P, Conde S. Insulin resistance is associated with tissue-specific regulation of HIF-1α and HIF-2α during mild chronic intermittent hypoxia. Respir Physiol Neurobiol 2016; 228:30-8. [DOI: 10.1016/j.resp.2016.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/03/2016] [Accepted: 03/12/2016] [Indexed: 01/18/2023]
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Matafome P, Rodrigues T, Pereira A, Letra L, Azevedo H, Paixão A, Silvério M, Almeida A, Sena C, Seiça R. Long-term globular adiponectin administration improves adipose tissue dysmetabolism in high-fat diet-fed Wistar rats. Arch Physiol Biochem 2014; 120:147-57. [PMID: 25142333 DOI: 10.3109/13813455.2014.950590] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Adiponectin administration to obese or type 2 diabetic patients is still far off, due to its expensive costs and absence of studies demonstrating the effectiveness of its chronic administration. We performed long-term globular adiponectin administration, testing its usefulness in improving adipose tissue metabolism. Adiponectin (98 υg/day) was administered through a subcutaneous minipump with continued release (28 days) to Wistar rats fed a high-fat diet. Adiponectin decreased body weight and adipocyte size, while decreasing circulating leptin levels. More, adiponectin was able to increase IkappaBalpha and PPARgamma levels and to prevent high-fat diet-induced impairment of insulin signalling, especially in epididymal adipose tissue. This resulted in improved glucose profile. High-fat diet caused an impairment of lipolysis in epididymal adipose tissue, which was partially restored by adiponectin treatment. Long-term globular adiponectin administration was able to improve pathways of insulin signalling and lipid storage in adipose tissue of high-fat diet-fed rats, contributing to a better metabolic profile.
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Affiliation(s)
- P Matafome
- Laboratory of Physiology, Institute of Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra , Portugal
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Crisóstomo J, Matafome P, Santos-Silva D, Rodrigues L, Sena CM, Pereira P, Seiça R. Methylglyoxal chronic administration promotes diabetes-like cardiac ischaemia disease in Wistar normal rats. Nutr Metab Cardiovasc Dis 2013; 23:1223-1230. [PMID: 23642929 DOI: 10.1016/j.numecd.2013.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 01/08/2013] [Accepted: 01/09/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND AND AIMS The influence of lifestyle is well documented, especially the diet regime, in the development of type 2 diabetes (T2D) and associated cardiovascular diseases. Diabetic patients have increased risk of suffering cardiac ischemia and impaired response to such accidents. Methylglyoxal (MG) circulates at high concentration in diabetics' blood and is linked to the development of diabetes chronic complications. We propose that besides promoting the cardiovascular disease, MG may also negatively regulate the endogenous cardioprotection pathways after ischemia. METHODS AND RESULTS We performed a comparative study between three animal groups: normal Wistar (W), type 2 diabetic non-obese Goto-Kakizaki (GK) and normal rats submitted to MG chronic administration (3 months) with gradually enhanced concentration, up to 75 mg/Kg (WMG). Hearts were submitted to different experimental conditions: control, ischemia and ischemia-reperfusion. Levels of oxidative stress markers, advanced glycation end-products (AGEs) and their receptors (RAGEs) were evaluated. The serine/threonine protein kinase Akt (Akt), crucial for cardiomyocytes recovery after ischemia, and apoptosis markers were also assessed. Levels of MG, systemic and cardiac oxidative stress markers, AGEs and RAGEs were similar in GK and WMG groups. Akt protein was negatively regulated by MG, leading to impaired apoptotic markers. CONCLUSION Chronic MG administration to normal rodents mimicked most diabetic alterations, being associated with the development of cardiovascular disease and the impairment of survival pathways. Our results demonstrate the negative effect of MG rich diet in healthy animals and suggest the potential of methylglyoxal as a therapeutic target in diabetes.
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Affiliation(s)
- J Crisóstomo
- Laboratory of Physiology, Institute of Biomedical Research in Light and Image (IBILI), Faculty of Medicine of University of Coimbra (FMUC), Coimbra, Portugal.
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Matafome P, Santos-Silva D, Sena CM, Seiça R. Common mechanisms of dysfunctional adipose tissue and obesity-related cancers. Diabetes Metab Res Rev 2013; 29:285-95. [PMID: 23390053 DOI: 10.1002/dmrr.2395] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 06/07/2012] [Accepted: 01/24/2013] [Indexed: 12/13/2022]
Abstract
The relation between cancer and metabolic disorders was recognized several decades ago, but the underlying mechanisms involved in cancer development and progression remain obscure. In the last years, many groups have been studying systemic adipose tissue markers in cancer patients. However, few consistent results were obtained. On the other hand, several studies revealed many aspects of adipose tissue physiology in obesity. Nowadays, it is recognized that excessive lipid uptake in adipocytes leads to hypertrophy and consequently to metabolic dysregulation, hypoxia, inflammation, impaired adipocytokine expression and angiogenesis, insulin resistance and macrophage recruitment. In obese patients, tumours commonly colocalize with excessive adipose tissue accumulation, and most of the features of hypertrophic adipose tissue are observed in cancer patients, namely breast and colon. This review aimed to summarize pathological adipose tissue alterations that may contribute to cancer aetiology and development.
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Affiliation(s)
- P Matafome
- Laboratory of Physiology and IBILI, Faculty of Medicine, University of Coimbra, 3000-354 Coimbra, Portugal.
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Matafome P, Santos-Silva D, Crisóstomo J, Rodrigues T, Rodrigues L, Sena CM, Pereira P, Seiça R. Methylglyoxal causes structural and functional alterations in adipose tissue independently of obesity. Arch Physiol Biochem 2012; 118:58-68. [PMID: 22364223 DOI: 10.3109/13813455.2012.658065] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
CONTEXT Adipose tissue is one of the first organs to develop insulin resistance even with moderate BMI. However, the contribution of developing hyperglycaemia and concomitant methylglyoxal increment to tissue dysfunction during type 2 diabetes progression was not addressed before. METHODS Young and aged Wistar and Goto-Kakizaki rats (non-obese model of type 2 diabetes) and a group of MG-treated W rats were used to investigate the chronic effects of hyperglycaemia and ageing and specifically MG-induced mechanisms. RESULTS Diabetic and aged rats showed decreased adipose tissue irrigation and interstitial hypoxia. Hyperglycaemia of diabetic rats leaded to fibrosis and accumulation of PAS-positive components, exacerbated in aged animals, which also showed decreased hipoadiponectinemia, increased MCP-1 expression and macrophage infiltration to glycated fibrotic regions. MG leaded to increased free fatty acids, hipoadiponectinemia, decreased irrigation, hypoxia and macrophage recruitment for glycated fibrotic regions. CONCLUSIONS MG contributes to dysfunction of adipose tissue during type 2 diabetes progression.
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Affiliation(s)
- P Matafome
- Laboratory of Physiology - IBILI, Faculty of Medicine, University of Coimbra, Portugal
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Matafome P, Louro T, Rodrigues L, Crisóstomo J, Nunes E, Amaral C, Monteiro P, Cipriano A, Seiça R. Metformin and atorvastatin combination further protect the liver in type 2 diabetes with hyperlipidaemia. Diabetes Metab Res Rev 2011; 27:54-62. [PMID: 21218508 DOI: 10.1002/dmrr.1157] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes are associated with dyslipidaemia, inflammation and oxidative stress. However, the pathophysiology of NAFLD in type 2 diabetes with hyperlipidaemia is not fully known, as well as the utility of the commonly prescribed anti-diabetic and lipid-lowering drugs in ameliorating liver injury markers. METHODS hepatic complications of type 2 diabetes with hyperlipidaemia and the effects of atorvastatin and metformin, isolated and in association, in systemic and hepatic inflammatory and oxidative stress markers were tested using genetic type 2 diabetic Goto-Kakizaki rats fed with a high-fat diet. RESULTS the high-fat diet aggravated the overall metabolic state and the hepatic markers of injury. All treatments decreased fasting glycaemia, insulin resistance and free fatty acid levels. Combined treatment further decreased C-reactive protein (CRP), adiponectin, liver tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6), systemic and hepatic oxidative stress and portal inflammation. CONCLUSIONS our data provides evidence of a greater benefit with a combination of atorvastatin and metformin in improving liver injury in type 2 diabetes with hyperlipidaemia.
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Affiliation(s)
- P Matafome
- Laboratory of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Center of Ophthalmology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
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Bento CF, Fernandes R, Matafome P, Sena C, Seiça R, Pereira P. Methylglyoxal-induced imbalance in the ratio of vascular endothelial growth factor to angiopoietin 2 secreted by retinal pigment epithelial cells leads to endothelial dysfunction. Exp Physiol 2010; 95:955-70. [PMID: 20562294 DOI: 10.1113/expphysiol.2010.053561] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Progressive microvascular complications are a main feature of diabetes and are associated with impairment of the angiogenic response. Methylglyoxal (MGO) has been implicated in the molecular events that lead to endothelial dysfunction in diabetes. In this study, we hypothesize that increased levels of MGO disrupt the ratio of vascular endothelial growth factor (VEGF) to angiopoietin 2 (Ang 2) secreted by retinal pigment epithelial (RPE) cells, which provides a key destabilizing signal that leads to apoptosis and decreased proliferation of retinal endothelial cells. Indeed, we show that MGO increases the levels of Ang 2 and dramatically decreases the levels of VEGF secreted by RPE cells in response to hypoxia. Downregulation of VEGF is likely to be related to decreased hypoxia-inducible factor-1alpha (HIF-1alpha) protein levels and HIF-1 transcriptional activity. Data further show that MGO-induced imbalance in the VEGF/Ang II ratio significantly changes the levels of BAX and Bcl-2 in endothelial cells. Moreover, this imbalance is accompanied by an increase in the activity of caspase-3 and decreased proliferation of endothelial cells. Data obtained in cell culture systems are consistent with observations in retinas of diabetic animals, where increased availability of MGO is associated with changes in distribution and levels of HIF-1alpha, VEGF and Ang 2 and increased microvascular permeability. In conclusion, the MGO-induced imbalance in the VEGF/Ang 2 ratio secreted by retinal epithelial cells activates apoptosis and decreases proliferation of retinal endothelial cells, which are likely to contribute to endothelial dysfunction in diabetic retinopathy.
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Affiliation(s)
- C F Bento
- Center of Ophthalmology and Vision Sciences (COCV) - IBILI, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Moreira P, Santos M, Seiça R, Oliveira C. Diabetes is a risk factor for Alzheimer disease: The role of mitochondria. J Neurol Sci 2009. [DOI: 10.1016/j.jns.2009.02.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Santos R, Cardoso S, Silva S, Correia S, Carvalho C, Crisóstomo J, Rodrigues L, Amaral C, Louro T, Matafome P, Santos M, Proença T, Duarte A, Seiça R, Moreira P. Food Deprivation Promotes Oxidative Imbalance in Rat Brain. J Food Sci 2009; 74:H8-H14. [DOI: 10.1111/j.1750-3841.2008.00982.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Matafome P, Nunes E, Louro T, Amaral C, Crisóstomo J, Rodrigues L, Moedas AR, Monteiro P, Cipriano A, Seiça R. A role for atorvastatin and insulin combination in protecting from liver injury in a model of type 2 diabetes with hyperlipidemia. Naunyn Schmiedebergs Arch Pharmacol 2008; 379:241-51. [DOI: 10.1007/s00210-008-0363-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Accepted: 09/30/2008] [Indexed: 12/12/2022]
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Sena CM, Louro T, Matafome P, Nunes E, Monteiro P, Seiça R. Antioxidant and vascular effects of gliclazide in type 2 diabetic rats fed high-fat diet. Physiol Res 2008; 58:203-209. [PMID: 18380531 DOI: 10.33549/physiolres.931480] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Diabetes mellitus is characterized by oxidative stress, which in turn determines endothelial dysfunction. Gliclazide is a sulphonylurea antidiabetic drug with antioxidant effects due to its azabicyclo-octyl ring. It has been reported to potentially protect the vasculature through improvements in plasma lipid levels and platelet function. We hypothesized that gliclazide has a beneficial effect on endothelial function in Goto-Kakizaki rats (GK), an animal model of type 2 diabetes fed an atherogenic diet for 4 months. We evaluated the influence of gliclazide on both metabolic and oxidative status and NO-mediated vasodilation. GKAD rats showed increased oxidative stress and impaired endothelium-dependent vasodilation. GKAD rats treated with gliclazide showed increased sensitivity to NO-mediated vasodilation, a significant decrease in fasting glycemia and insulinemia, and a significant decrease in systemic oxidative stress. In conclusion, our results suggest that gliclazide treatment improves NO-mediated vasodilation in diabetic GK rats with dyslipidemia probably due to its antioxidant effects, although we cannot rule out substantial benefits due to a reduction in fasting blood glucose. The availability of a compound that simultaneously decreases hyperglycemia, hyperinsulinemia, and inhibits oxidative stress is a promising therapeutic candidate for the prevention of vascular complications of diabetes.
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Affiliation(s)
- C M Sena
- Institute of Physiology, University of Coimbra, Coimbra, Portugal.
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Sena CM, Barosa C, Nunes E, Seiça R, Jones JG. Sources of endogenous glucose production in the Goto–Kakizaki diabetic rat. Diabetes & Metabolism 2007; 33:296-302. [PMID: 17553720 DOI: 10.1016/j.diabet.2007.03.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 03/18/2007] [Indexed: 10/23/2022]
Abstract
Plasma glucose, insulin and glucose tolerance were quantified in diabetic Goto-Kakizaki (GK) rats (342+/-45 g, n = 5) and compared with weight-matched non-diabetic Wistars (307+/-30 g, n = 8). Compared to Wistars, GK rats had higher fasting plasma insulin (219+/-50 versus 44+/-14 pmol/l, P<0.002) and glucose (9.2+/-2.3 versus 5.5+/-0.5 mmol/l, P<0.025). GK rats showed impaired glucose tolerance (IPGTT 2 h plasma glucose=14+/-1.5 versus 6.4+/-0.1 mmol/l, P<0.001). Endogenous glucose production (EGP) from glycogenolysis, phosphoenolpyruvate (PEP) and glycerol after 6 hours of fasting was quantified by a primed infusion of [U-(13)C]glucose and (2)H(2)O tracers and (2)H/(13)C NMR analysis of plasma glucose. EGP was higher in GK compared to Wistar rats (191+/-16 versus 104+/-27 mumol/kg per min, P<0.005). This was sustained by increased gluconeogenesis from PEP (85+/-12 versus 35+/-4 mumol/kg per min, P<0.02). Gluconeogenesis from glycerol was not different (20+/-3 in Wistar versus 30+/-6 mumol/kg per min for GK), and glycogenolysis fluxes were also not significantly different (76+/-23 mumol/kg per min for GK versus 52+/-19 mumol/kg per min for Wistar). The Cori cycle accounted for most of PEP gluconeogenesis in both Wistar and GK rats (85+/-15% and 77+/-10%, respectively). Therefore, increased gluconeogenesis in GK rats is largely sustained by increased Cori cycling while the maintenance of glycogenolysis indicates a failure in hepatic autoregulation of EGP.
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Affiliation(s)
- C M Sena
- Institute of Physiology, Faculty of Medicine, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal.
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Nunes E, Peixoto F, Louro T, Sena CM, Santos MS, Matafome P, Moreira PI, Seiça R. Soybean oil treatment impairs glucose-stimulated insulin secretion and changes fatty acid composition of normal and diabetic islets. Acta Diabetol 2007; 44:121-30. [PMID: 17721750 DOI: 10.1007/s00592-007-0252-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Accepted: 03/19/2007] [Indexed: 10/22/2022]
Abstract
We investigated the effect of sub-chronic soybean oil (SO) treatment on the insulin secretion and fatty acid composition of islets of Langerhans obtained from Goto-Kakizaki (GK), a model of type 2 diabetes, and normal Wistar rats. We observed that soybean-treated Wistar rats present insulin resistance and defective islet insulin secretion when compared with untreated Wistar rats. The decrease in insulin secretion occurred at all concentrations of glucose and arginine tested. Furthermore we observed that soybean-treated normal islets present a significant decrease in two saturated fatty acids, myristic and heneicosanoic acids, and one monounsaturated eicosenoic acid, and the appearance of the monounsaturated erucic acid. Concerning diabetic animals, we observed that soybean-treated diabetic rats, when compared with untreated GK rats, present an increase in plasma non-fasting free fatty acids, an exacerbation of islet insulin secretion impairment in all conditions tested and a significant decrease in the monounsaturated palmitoleic acid. Altogether our results show that SO treatment results in a decrease of insulin secretion and alterations on fatty acid composition in normal and diabetic islets. Furthermore, the impairment of insulin secretion, islet erucic acid and fasting plasma insulin levels are similar in treated normal and untreated diabetic rats, suggesting that SO could have a deleterious effect on beta-cell function and insulin sensitivity.
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Affiliation(s)
- E Nunes
- Faculty of Medicine, Institute of Physiology, Rua Larga, PT-3004-504, Coimbra, Portugal
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Abstract
This study evaluated and compared the effect of insulin treatment on the status of brain, heart and kidney mitochondria isolated from 12-week streptozotocin (STZ)-induced diabetic rats versus STZ-diabetic animals treated with insulin during a period of 4 weeks. Mitochondria isolated from 12-week citrate (vehicle)-treated rats were used as control. Several mitochondrial parameters were evaluated: respiratory indexes (state 3 and 4 of respiration, respiratory control and ADP/O ratios), transmembrane potential, depolarization and repolarization levels, ATP, glutathione and coenzyme Q contents, production of hydrogen peroxide, superoxide dismutase, glutathione peroxidase and glutathione reductase activities and the ability of mitochondria to accumulate calcium. We observed that diabetes promoted a significant decrease in kidney and brain mitochondrial coenzyme Q9 content while this parameter was increased in heart mitochondria. Furthermore, diabetes induced a significant increase in hydrogen peroxide production in kidney mitochondria this effect being accompanied by a significant increase in glutathione peroxidase and reductase activities. Furthermore, brain mitochondria isolated from diabetic animals presented a lower ATP content and ability to accumulate calcium. In contrast, heart and kidney mitochondria presented a slight higher capacity to accumulate calcium. Insulin treatment normalized the levels of coenzyme Q9 and glutathione peroxidase and reductase activities and increased ATP content and the ability to accumulate calcium. Altogether these results suggest that insulin treatment attenuates diabetes-induced mitochondrial alterations protecting against the increase in oxidative stress and improving oxidative phosphorylation efficiency. In this line, insulin therapy, besides its well-known importance in the maintenance of glycemic control, may help to protect against mitochondrial dysfunction associated to several age-related disorders such as diabetes.
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Affiliation(s)
- P I Moreira
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
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Moreira PI, Santos MS, Moreno AM, Proença T, Seiça R, Oliveira CR. Effect of streptozotocin-induced diabetes on rat brain mitochondria. J Neuroendocrinol 2004; 16:32-8. [PMID: 14962073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
This study evaluated several parameters related to mitochondrial function and oxidative stress in streptozotocin (STZ)-treated rats, a model of type 1 diabetes. For this purpose, the respiratory indexes (RCR and ADP/O ratio), mitochondrial transmembrane potential (DeltaPsim), repolarization lag phase, repolarization level, mitochondrial enzymatic activities, ATP and malondialdehyde (MDA) levels, reduced glutathione (GSH), vitamin E and cardiolipin contents were determined in rat brain mitochondria isolated after 4 and 9 weeks after STZ treatment. Brain mitochondria isolated from citrate (vehicle)-treated Wistar rats were used as control. We observed that STZ-induced diabetes did not substantially affect brain mitochondrial function. Instead, 4-week diabetic rats presented higher mitochondrial respiratory chain enzymatic activities, especially succinate-cytochrome C reductase activity, compared to 4-week control rats. In 9-week diabetic rats, only a significant decrease in cardiolipin content was observed; however, a significant increase in mitochondrial GSH content occurred. All other parameters analysed remained statistically unchanged. From these results, we conclude that STZ-induced diabetes did not promote brain mitochondrial dysfunction, suggesting that oxidative stress associated with type 1 diabetes is not directly related to mitochondrial dysfunction, but probably is related to extramitochondrial factor(s).
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Affiliation(s)
- P I Moreira
- Department of Zoology, Faculty of Sciences and Technology, University Hospitals, Institute of Physiology, Faculty of Medicine, and Institute of Biochemistry, Faculty of Medicine, Center for Neuroscience of Coimbra, University of Coimbra, Coimbra, Portugal
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Ferreira FM, Oliveira PJ, Rolo AP, Santos MS, Moreno AJ, da Cunha MF, Seiça R, Palmeira CM. Cholestasis induced by chronic treatment with alpha-naphthyl-isothiocyanate (ANIT) affects rat renal mitochondrial bioenergetics. Arch Toxicol 2003; 77:194-200. [PMID: 12698234 DOI: 10.1007/s00204-003-0441-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2002] [Accepted: 01/15/2003] [Indexed: 10/20/2022]
Abstract
Chronic cholestasis is characteristic of many human liver diseases. Renal injury has been often associated with this type of disease. The aim of this study was to evaluate the effect of cholestasis on kidney mitochondrial bioenergetics following in vivo chronic administration of alpha-naphthyl-isothiocyanate (ANIT), a known cholestatic agent. Serum markers of renal injury, kidney morphology and endogenous adenine nucleotides were measured in ANIT-treated rats (80 mg/kg per week s.c. for 16 weeks). Changes in membrane potential and mitochondrial respiration as well as alterations in mitochondrial calcium homeostasis were monitored. Cholestatic animals shown no alterations in renal morphology when compared with control. Additionally, following chronic ANIT administration, no significant alterations in mitochondrial respiratory function have been shown. The phosphorylation capacity of cholestatic kidney mitochondria was enhanced. Associated with these parameters, mitochondria from treated animals exhibited a decreased susceptibility to disruption of mitochondrial calcium homeostasis, due to permeability transition induction. These data suggest that, despite being submitted to chronic treatment with ANIT, kidney mitochondria from cholestasis-induced rats present some defense mechanisms to circumvent this aggression. They show improved phosphorylative capacity and, moreover, a decreased susceptibility to mitochondrial permeability transition induction, probably due to adaptative mechanisms of calcium transport.
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Affiliation(s)
- F M Ferreira
- Center for Neurosciences and Cell Biology, Department of Zoology, University of Coimbra, 3004-517, Coimbra, Portugal
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Palmeira CM, Santos DL, Seiça R, Moreno AJ, Santos MS. Enhanced mitochondrial testicular antioxidant capacity in Goto-Kakizaki diabetic rats: role of coenzyme Q. Am J Physiol Cell Physiol 2001; 281:C1023-8. [PMID: 11502580 DOI: 10.1152/ajpcell.2001.281.3.c1023] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Because diabetes mellitus is associated with impairment of testicular function, ultimately leading to reduced fertility, this study was conducted to evaluate the existence of a cause-effect relationship between increased oxidative stress in diabetes and reduced mitochondrial antioxidant capacity. The susceptibility to oxidative stress and antioxidant capacity (in terms of glutathione, coenzyme Q, and vitamin E content) of testis mitochondrial preparations isolated from Goto-Kakizaki (GK) non-insulin-dependent diabetic rats and from Wistar control rats, 1 yr of age, was evaluated. It was found that GK mitochondrial preparations showed a lower susceptibility to lipid peroxidation induced by ADP/Fe(2+), as evaluated by oxygen consumption and reactive oxygen species generation. The decreased susceptibility to oxidative stress in diabetic rats was associated with an increase in mitochondrial glutathione and coenzyme Q9 contents, whereas vitamin E was not changed. These results demonstrate a higher antioxidant capacity in diabetic GK rats. We suggest this is an adaptive response of testis mitochondria to the increased oxidative damage in diabetes mellitus.
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Affiliation(s)
- C M Palmeira
- Department of Zoology, University of Coimbra, Portugal.
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Santos MS, Santos DL, Palmeira CM, Seiça R, Moreno AJ, Oliveira CR. Brain and liver mitochondria isolated from diabetic Goto-Kakizaki rats show different susceptibility to induced oxidative stress. Diabetes Metab Res Rev 2001; 17:223-30. [PMID: 11424235 DOI: 10.1002/dmrr.200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Increased oxidative stress and changes in antioxidant capacity observed in both clinical and experimental diabetes mellitus have been implicated in the etiology of chronic diabetic complications. Many authors have shown that hyperglycemia leads to an increase in lipid peroxidation in diabetic patients and animals reflecting a rise in reactive oxygen species production. The aim of the study was to compare the susceptibility of mitochondria from brain and liver of Goto-Kakizaki (12-month-old diabetic) rats (GK rats), a model of non-insulin dependent diabetes mellitus, to oxidative stress and antioxidant defenses. METHODS Brain and liver mitochondrial preparations were obtained by differential centrifugation. Oxidative damage injury was induced in vitro by the oxidant pair ADP/Fe(2+) and the extent of membrane oxidation was assessed by oxygen consumption, malondialdehyde (MDA) and thiobarbituric acid reactive substances (TBARS) formation. Coenzyme Q and alpha-tocopherol contents were measured by high-performance liquid chromatography (HPLC). RESULTS Brain mitochondria isolated from 12-month-old control rats displayed a higher susceptibility to lipid peroxidation, as assessed by oxygen consumption and formation of MDA and TBARS, compared to liver mitochondria. In GK rats, mitochondria isolated from brain were more susceptible to in vitro oxidative damage than brain mitochondria from normal rats. In contrast, liver mitochondria from diabetic rats were less susceptible to oxidative damage than mitochondria from normal rats. This decreased susceptibility was inversely related to their alpha-tocopherol and coenzyme Q (CoQ) content. CONCLUSIONS The present results indicate that the diabetic state can result in an elevation of both alpha-tocopherol and CoQ content in liver, which may be involved in the elimination of mitochondrially generated reactive oxygen species. The difference in the antioxidant defense mechanisms in the brain and liver mitochondrial preparations of moderately hyperglycemic diabetic GK rats may correspond to a different adaptive response of the cells to the increased oxidative damage in diabetes.
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Affiliation(s)
- M S Santos
- Center for Neurosciences and Cell Biology of Coimbra, Department of Zoology, University of Coimbra, Coimbra, Portugal
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Oliveira PJ, Rolo AP, Seiça R, Palmeira CM, Santos MS, Moreno AJ. Decreased susceptibility of heart mitochondria from diabetic GK rats to mitochondrial permeability transition induced by calcium phosphate. Biosci Rep 2001; 21:45-53. [PMID: 11508693 DOI: 10.1023/a:1010482017540] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Type 2 diabetes (or non-insulin dependent diabetes mellitus, NIDDM) is a common metabolic disease in man. The Goto-Kakizaki (GK) rat has been designed as a NIDDM model. Previous studies with this strain have shown differences at the mitochondrial level. The mitochondrial permeability transition (MPT) is a widely studied phenomenon but yet poorly understood, that leads to mitochondrial dysfunction and cell death. The aim of this work was to compare the differences in susceptibility of induction of the MPT with calcium phosphate in GK and Wistar rats. Our results show that heart mitochondria from GK rats are less susceptible to the induction of MPT, and show a larger calcium accumulation before the overall loss of mitochondrial impermeability.
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Affiliation(s)
- P J Oliveira
- Centro de Neurociências de Coimbra, Dep. Zoologia, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Portugal
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Santos MS, Duarte AI, Matos MJ, Proença T, Seiça R, Oliveira CR. Synaptosomes isolated from Goto-Kakizaki diabetic rat brain exhibit increased resistance to oxidative stress: role of vitamin E. Life Sci 2000; 67:3061-73. [PMID: 11125843 DOI: 10.1016/s0024-3205(00)00892-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Increased oxidative stress is believed to be an important factor in the development of diabetic complications. In this study, the effect of diabetes on the susceptibility of synaptosomes to oxidative stress, induced by the oxidizing system ascorbate/Fe2+, on the activity of antioxidant enzymes and on the levels of glutathione and vitamin E was investigated. Synaptosomes were isolated from brain of 29-weeks-old Goto-Kakizaki (GK) rats, a model of non-insulin dependent diabetes mellitus and from normal Wistar rats. Synaptosomes isolated from GK rats displayed a lower susceptibility to lipid peroxidation, as assessed by quantifying thiobarbituric acid reactive substances (TBARS), than normal rats (5.33 +/- 0.79 and 7.58 +/- 0.7 nmol TBARS/mg protein, respectively). In the absence of oxidants, no significant differences were found between the levels of peroxidation in synaptosomes of diabetic or control rats. Superoxide dismutase (SOD), glutathione peroxidase and glutathione reductase activities were unaltered in the brain of diabetic rats. There were no statistically significant differences in fatty acid composition of total lipids and reduced glutathione levels in synaptosomes of diabetic and control rats. The decreased susceptibility to membrane lipid peroxidation of diabetic rats synaptosomes correlated with a 1.3-fold increase in synaptosomal vitamin E levels. Vitamin E levels in plasma were also higher in diabetic rats (21.32 micromol/l) as compared to normal rats (15.13 micromol/l). We conclude that the increased resistance to lipid peroxidation in GK rat brain synaptosomes may be due to the increased vitamin E content, suggesting that diabetic animals might develop enhanced defense systems against brain oxidative stress.
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Affiliation(s)
- M S Santos
- Department of Zoology, Center for Neurosciences of Coimbra, University of Coimbra, Portugal
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Duarte A, Santos M, Seiça R, Resende de Oliveira C. Effect of oxidative stress on the uptake of GABA and glutamate in synaptosomes isolated from diabetic rat brain. Neuroendocrinology 2000; 72:179-86. [PMID: 11025412 DOI: 10.1159/000054585] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It has been suggested that increased oxidative stress might be involved in the pathophysiology of diabetic complications. In this study, we investigated the effect of diabetes on the susceptibility of synaptosomes to oxidative stress (induced by the oxidizing pair ascorbate/Fe(2+)) and on the uptake of the amino acid neurotransmitters gamma-aminobutyric acid (GABA) and glutamate. We found a lower susceptibility of synaptosomes isolated from Goto-Kakizaki (GK) rats, a model of non-insulin-dependent diabetes mellitus, to lipid peroxidation as compared with synaptosomes isolated from Wistar control rats (6.40+/-1.05 and 12.14+/-1.46 nmol thiobarbituric acid reactive substance/mg protein, respectively). The lower susceptibility of GK rat synaptosomes to membrane lipid peroxidation correlates with an increase in synaptosomal vitamin E levels (835+/-58.04 and 624.26+/-50.26 pmol/mg protein in diabetic and normal rats, respectively). In the absence of ascorbate/Fe(2+), no significant differences were observed between the levels of lipid peroxidation of synaptosomes isolated from diabetic and normal rats. Studies of neurotransmitter uptake show that the [(3)H]glutamate uptake was decreased by about 30% in diabetic GK rats as compared with control Wistar rats, whereas the [(3)H]GABA uptake was not significantly different from controls. Under oxidizing conditions, the glutamate uptake in diabetic rats was unaffected, and a decreased GABA uptake (41.39+/-4.41 and 60.96+/-6.4% of control in GK and Wistar rats, respectively) was observed. We conclude that the increased resistance to oxidative stress in GK rat synaptosomes may be due to the increased vitamin E content and that diabetic state and oxidative stress conditions differentially affected the uptake of the neurotransmitters GABA and glutamate.
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Affiliation(s)
- A Duarte
- Center for Neurosciences of Coimbra, University of Coimbra, Portugal
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Pereira C, Moreira P, Seiça R, Santos MS, Oliveira CR. Susceptibility to beta-amyloid-induced toxicity is decreased in goto-kakizaki diabetic rats: involvement of oxidative stress. Exp Neurol 2000; 161:383-91. [PMID: 10683303 DOI: 10.1006/exnr.1999.7270] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The response of synaptosomes isolated from Wistar non-diabetic rats and Goto-Kakizaki (GK) diabetic rats to the beta-amyloid fragment Abeta25-35 was compared. The synaptosomal redox activity, evaluated by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, was shown to be decreased in GK rats (72.8 +/- 7.45% of MTT reduction). However, the reduction of MTT was decreased in synaptosomes of Wistar rats upon Abeta25-35 treatment (84.47 +/- 3.73%), while in GK rats it was not affected. Abeta25-35 induced lipid peroxidation in synaptosomes of Wistar rats, but not in that of GK rats, leading to an 1.5-fold increase in thiobarbituric acid reactive substances (TBARS) levels. In the absence of Abeta25-35, basal TBARS levels were 1.6-fold higher in GK rats. In the former preparations, the content in vitamin E was also higher (2-fold). A decrease in ATP levels, of about 2-fold, was observed in synaptosomes of Wistar rats treated with Abeta25-35, while no significant changes were observed in synaptosomes of GK rats. No significant differences between the two groups were detected in the basal ATP levels. The extrasynaptosomal accumulation of aspartate and glutamate increased upon Abeta25-35 treatment, only in synaptosomes of Wistar rats (aspartate and glutamate accumulation increased by 1.1-fold and 1.5-fold, respectively), while the accumulation of glycine increased in both Wistar (by 1.8-fold) and GK (by 2.2-fold) rats. No statistical differences in the basal accumulation of aminoacids were observed. These results show that synaptosomes of GK diabetic rats have a lower redox activity, but are less susceptible to the Abeta25-35-induced toxicity. Data also suggest that oxidative stress occurs in this hyperglycemia animal model and that an increase in the antioxidant defense systems may exert protection against toxic insults. This mechanism, occuring in the early phases of diabetes, may correspond to an adaptive response.
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Affiliation(s)
- C Pereira
- Department of Zoology, Faculty of Medicine, Coimbra, 3004-504, Portugal
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Abstract
Type 2 diabetes mellitus is one of the most common chronic metabolic diseases in man. Due to long-term complications of the disease, severely decreasing the quality of life of diabetic patients, early interventions to obviate the risk of complications are of major importance. Therefore, diabetic animal models are of major importance in research for interventional treatment of type 2 diabetes. In this work we investigated the possible alterations in mitochondrial energetic metabolism of Goto-Kakizaki (GK) rats during the progression of the disease, since glucose metabolism is closely related to intracellular ATP content. For that reason, respiratory indexes (state 4, state 3, RCR and ADP/O) were evaluated either in the presence of NAD- or FAD-linked substrates (glutamate + malate and succinate, respectively) in mitochondrial preparations of GK and control rats with 8, 12, 26 and 52 weeks of age. Until the age of 1 year (52 weeks) we found no impairment of mitochondrial respiratory indexes both in the presence of glutamate + malate and succinate. In conclusion, this study indicates that GK rat is a good model for studying the initial events of diabetes, since it presents no impairment of liver mitochondrial functions during the first year of life, contrasting clearly with pharmacological induced diabetes.
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Affiliation(s)
- F M Ferreira
- Department of Zoology, Center for Neurosciences and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
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Ferreira FM, Palmeira CM, Matos MJ, Seiça R, Santos MS. Decreased susceptibility to lipid peroxidation of Goto-Kakizaki rats: relationship to mitochondrial antioxidant capacity. Life Sci 1999; 65:1013-25. [PMID: 10499869 DOI: 10.1016/s0024-3205(99)00332-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The respiratory function and the antioxidant capacity of liver mitochondrial preparations isolated from Goto-Kakizaki non-insulin dependent diabetic rats and from Wistar control rats, with the age of 6 months, were compared. It was found that Goto-Kakizaki mitochondrial preparations presented a higher coupling between oxidative and phosphorylative systems, compared to non-diabetic preparations. Goto-Kakizaki mitochondria presented a lower susceptibility to lipid peroxidation induced by ADP/Fe2+, as evaluated by the formation of thiobarbituric acid substances. The decreased susceptibility to peroxidation in diabetic rats was correlated with an increase in mitochondrial vitamin E (alpha-tocopherol) content and GSH/GSSG ratio. Moreover, the glutathione reductase activity was significantly increased, whereas the glutathione peroxidase was decreased. Superoxide dismutase activity was unchanged in diabetic rats. Fatty acid analyses showed that the content in polyunsaturated fatty acids of Goto-Kakizaki mitochondrial membranes was significantly higher compared to controls. These results indicate that the lower susceptibility to lipid peroxidation of mitochondria from diabetic rats was related to their antioxidant defense systems, and may correspond to an adaptative response of the cells against oxidative stress in the early phase of diabetes.
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Affiliation(s)
- F M Ferreira
- Center for Neurosciences of Coimbra, Department of Zoology, University of Coimbra, Portugal.
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32
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Abstract
Respiratory indexes and the transmembrane electrical potential (delta psi) were evaluated in mitochondrial preparations from 6-month-old Goto-Kakizaki (GK) and Wistar rats in the presence of glutamate + malate and succinate. We found that in diabetic GK mitochondria, flavin adenine dinucleotide (FAD)-linked respiratory indexes (respiratory control ratio [RCR] and adenosine diphosphate [ADP] to oxygen ratio [ADP/O]) are increased and uncoupled respiration is largely enhanced, indicating increased respiratory chain activity in GK rats. Delta psi development in GK mitochondrial preparations, energized using glutamate + malate or succinate as substrates, and the repolarization rate upon phosphorylation of the added ADP were significantly higher in GK mitochondrial preparations. These results indicate an enhanced activity of the phosphorylation system, confirmed by evaluating delta psi development when the mitochondria are energized by adenosine triphosphate (ATP). Moreover, recovery of the potential upon a phosphorylative cycle is increased in GK mitochondria, reflecting a more efficient coupling between the phosphorylative and oxidative system. Contrasting with results obtained for alloxan- or streptozotocin-induced diabetic rats, this study clearly demonstrates no impairment of mitochondrial bioenergetics in diabetic GK rats. On the contrary, at this age, we observed a higher efficiency of the phosphorylation system as compared with Wistar rats.
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Affiliation(s)
- F M Ferreira
- Department of Zoology and the Faculty of Medicine, Center for Neurosciences of Coimbra, University of Coimbra, Portugal
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