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Kassem SA, Raz I. Is there evidence that oral hypoglycemic agents reduce cardiovascular morbidity or mortality? No. Diabetes Care 2009; 32 Suppl 2:S337-41. [PMID: 19875577 PMCID: PMC2811474 DOI: 10.2337/dc09-s335] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Sameer A Kassem
- Diabetes Unit, Department of Internal Medicine, Hadassah Medical Center, Jerusalem, Israel.
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Ansari G, Mojtahedzadeh M, Kajbaf F, Najafi A, Khajavi MR, Khalili H, Rouini MR, Ahmadi H, Abdollahi M. How does blood glucose control with metformin influence intensive insulin protocols? Evidence for involvement of oxidative stress and inflammatory cytokines. Adv Ther 2008; 25:681-702. [PMID: 18636232 DOI: 10.1007/s12325-008-0075-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Recent investigations have revealed that control of hyperglycaemia with insulin improves outcomes. The cornerstone of hyperglycaemia in critically ill patients is insulin resistance and it remains refractory to intensive insulin protocols. We designed this study to evaluate the efficacy and safety of a new intensive insulin therapy (IIT) protocol combined with metformin. METHODS Twenty-one patients with systemic inflammatory response syndrome and a blood glucose level of >120 mg/dl admitted to an intensive care unit (ICU) were randomised to receive either intravenous infusion of IIT alone (n=11) or combined with metformin (IIT+MET; n=10) to maintain a blood glucose level (BGL) of 80-120 mg/dl. Blood samples were obtained at baseline and at 48 hours, 96 hours and 7 days after initiation of the study. Samples were analysed for interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-alpha) and nitric oxide (NO) as inflammatory mediators; plasminogen activation inhibitor-1 (PAI-1) as a coagulation mediator; and thiobarbituric reactive substances (TBARS), total antioxidant power (TAP) and total thiol molecules (TTM) as oxidative stress parameters. RESULTS The addition of metformin to the IIT protocol decreased insulin requirement and concentration of insulin and C-peptide. With both treatments at most time points, the mean plasma levels of IL-6, TNF-alpha, NO, PAI-1 and TBARS were found to be significantly lower compared with baseline. Antioxidant activity was increased in both arms with increasing TAP and TTM (P<0.05). There was no significant difference between the two groups regarding reported beneficial effects on these parameters. Therapeutic Intervention Scoring System-28 (TISS-28) score, an index of nursing workload and number of therapeutic interventions, decreased in the IIT+MET group (P<0.01). We did not observe any occurrence of hyperlactataemia or acidosis in the IIT+MET group. CONCLUSION Metformin plus insulin appears to lower the incidence of insulin resistance, lower insulin requirement while maintaining blood glucose level control, and consequently lower the incidence of adverse effects related to high-dose insulin therapy, particularly hypoglycaemia, and also declined nursing workload. Both treatment protocols showed improvements in inflammatory cytokine levels. Further studies with larger sample sizes are warranted to determine the undiscovered facts of insulin-sensitising agents in critically ill patients.
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Affiliation(s)
- Ghazal Ansari
- Faculty of Pharmacy, and Pharmaceutical Sciences Research Centre, Tehran University of Medical Sciences, Tehran, Iran
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Hsieh CH, He CT, Lee CH, Wu LY, Hung YJ. Both slow-release and regular-form metformin improve glycemic control without altering plasma visfatin level in patients with type 2 diabetes mellitus. Metabolism 2007; 56:1087-92. [PMID: 17618954 DOI: 10.1016/j.metabol.2007.03.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Accepted: 03/20/2007] [Indexed: 11/27/2022]
Abstract
Both slow-release (SR) and regular-release (RR) metformin were effective in the treatment of type 2 diabetes mellitus. We compare the efficacy, safety, and effects on serum adipocytokines and inflammatory markers of both regimens in patients with type 2 diabetes mellitus. A prospective, randomized, double-blind study enrolled 55 patients with type 2 diabetes mellitus, which were randomly assigned to receive either metformin SR or RR (at a maximal dosage of 2000 mg/d for 12 weeks). Glycosylated hemoglobin A1c (HbA1c), fasting plasma glucose, adipocytokines, C-reactive protein, and insulin resistance and pancreatic beta-cell function were measured before and after treatment. Significant decreases (P<.001) in mean HbA1c and fasting plasma glucose levels were observed in each group. However, the mean changes in HbA1c from baseline to end point in the 2 groups were not significantly different. Changes in metabolic parameters were similar except that a decreased total cholesterol level was observed in the metformin RR group. Neither regimen treatment had any influence on insulin resistance, but metformin RR improved beta-cell function. Neither regimen had an effect on serum adipocytokines or inflammatory markers. Once-daily metformin SR was as safe and effective as metformin RR in type 2 diabetic patients. Neither dosage form affected serum adipocytokines and inflammatory markers.
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Affiliation(s)
- Chang-Hsun Hsieh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Tri-Service General Hospital, Taipei, Taiwan, ROC
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Ajjan RA, Grant PJ. Cardiovascular disease prevention in patients with type 2 diabetes: The role of oral anti-diabetic agents. Diab Vasc Dis Res 2006; 3:147-58. [PMID: 17160909 DOI: 10.3132/dvdr.2006.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Multiple risk factor intervention is essential in order to prevent cardiovascular (CV) disease in patients with diabetes. Therefore, to reduce atherothrombotic events, an ideal oral anti-diabetic agent should be able to modulate most, and preferably all, cardiovascular risk factors associated with diabetes. Of the currently available agents, the insulin sensitisers (metformin, thiazolidinediones) seem to have most promise in cardiovascular protection. Metformin has a positive effect on several CV risk factors; outcome studies have shown that this agent reduces cardiac events in overweight subjects with diabetes. In a similar manner, thiazolidinediones (rosiglitazone, pioglitazone) have a wide spectrum of activity, favourably modulating most risk factors, with evidence to suggest a reduction in CV events with this class of drugs. Agents in the sulphonylurea group have beneficial, though inconsistent, effects on some risk factors but outcome studies have failed to show a cardioprotective role for these agents. New classes of drugs to manage type 2 diabetes are currently at various stages of development and their role in prevention of cardiovascular disease awaits evaluation. At present, first-line management of insulin-resistant type 2 diabetes should utilise metformin, with the addition of thiazolidinediones and sulphonylureas to achieve optimal glycaemic control.
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Affiliation(s)
- Ramzi A Ajjan
- Acadamic Unit of Molecular Vascular Medicine, Leeds Institute of Genetics Health and Therapeutics, Faculty of Medicine and Health, University of Leeds, UK
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Abstract
Subclinical, low-grade systemic inflammation has been observed in patients with type 2 diabetes and in those at increased risk of the disease. This may be more than an epiphenomenon. Alleles of genes encoding immune/inflammatory mediators are associated with the disease, and the two major environmental factors the contribute to the risk of type 2 diabetes-diet and physical activity-have a direct impact on levels of systemic immune mediators. In animal models, targeting of immune genes enhanced or suppressed the development of obesity or diabetes. Obesity is associated with the infiltration and proinflammatory activity of macrophages in adipose tissue, and immune mediators may be important regulators of insulin resistance, mitochondrial function, ectopic lipid storage and beta cell dysfunction or death. Intervention studies targeting these pathways would help to determine the contribution of an activated innate immune system to the development of type 2 diabetes.
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Affiliation(s)
- H Kolb
- German Diabetes Center, Leibniz-Institute at the University of Düsseldorf, Düsseldorf, Germany.
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Biarnés J, Fernández-Real JM, Fernández-Castañer M, del Mar García M, Soler J, Ricart W. Differential regulation of insulin action and tumor necrosis factor alpha system activity by metformin. Metabolism 2005; 54:235-9. [PMID: 15690319 DOI: 10.1016/j.metabol.2004.08.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Tumor necrosis factor alpha has a key role in insulin resistance. We study the effects of metformin on glucose tolerance, insulin resistance, beta cell function, and soluble tumor necrosis factor receptor (sTNFR) levels. METHODS We performed a double-blind, randomized metformin-placebo study. Twenty-three subjects with impaired glucose tolerance or impaired fasting glucose were studied. Oral glucose tolerance, homeostasis model assessment, and continuous infusion of glucose with model assessment tests were used to evaluate glucose tolerance, insulin sensitivity, and beta cell function, respectively. Soluble tumor necrosis factor receptor levels were measured before and after therapy. Repeated measures analysis of variance was used for statistical analysis. RESULTS After 12-week treatment, fasting glucose (110.1 +/- 9.9 to 98.9 +/- 15.7 mg/dl, P < .001), fasting insulin (11.6 +/- 5.4 to 8.8 +/- 3.5 mU/L, P = .05), fasting C-peptide (2.5 +/- 0.7 to 1.8 +/- 0.5 ng/mL, P < .05), and achieved C-peptide (5.2 +/- 1.2 to 4.2 +/- 1 ng/mL, P < .05) levels decreased in the metformin group. In addition, there was an improvement in insulin sensitivity (37.4% +/- 15.2% to 50.4% +/- 23.2%, P < .05) with unchanged sTNFR1 (2.0 +/- 0.8 to 2.3 +/- 1.2 microg/L, P = NS) and sTNFR2 (4.8 +/- 1.7 to 4.4 +/- 1.2 microg/L, P = NS) levels. CONCLUSIONS Metformin is able to reverse insulin resistance and hyperglycemia in high-risk subjects for type 2 diabetes mellitus independently of the effects on tumor necrosis factor alpha system activity.
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Affiliation(s)
- Josefina Biarnés
- Diabetes, Endocrinology and Nutrition Unit, Hospital University Dr Josep Trueta de Girona, 17007 Girona, Spain.
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Ritchie SA, Ewart MA, Perry CG, Connell JMC, Salt IP. The role of insulin and the adipocytokines in regulation of vascular endothelial function. Clin Sci (Lond) 2004; 107:519-32. [PMID: 15324298 DOI: 10.1042/cs20040190] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vascular integrity in the healthy endothelium is maintained through the release of a variety of paracrine factors such as NO (nitric oxide). Endothelial dysfunction, characterized by reduced NO bioavailability, is associated with obesity, insulin resistance and Type II diabetes. Insulin has been demonstrated to have direct effects on the endothelium to increase NO bioavailability. Therefore altered insulin signalling in the endothelium represents a candidate mechanism underlying the association between insulin resistance and endothelial dysfunction. In recent years, it has become apparent that insulin sensitivity is regulated by the adipocytokines, a group of bioactive proteins secreted by adipose tissue. Secretion of adipocytokines is altered in obese individuals and there is increasing evidence that the adipocytokines have direct effects on the vascular endothelium. A number of current antidiabetic strategies have been demonstrated to have beneficial effects on endothelial function and to alter adipocytokine concentrations in addition to their effects on glucose homoeostasis. In this review we will explore the notion that the association between insulin resistance and endothelial dysfunction is accounted for by adipocytokine action on the endothelium. In addition, we examine the effects of weight loss, exercise and antidiabetic drugs on adipocytokine availability and endothelial function.
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Affiliation(s)
- Stuart A Ritchie
- Henry Wellcome Laboratory of Cell Biology, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
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Ohara S, Komatsu R, Matsuyama T. Short-term effect of buformin, a biguanide, on insulin sensitivity, soluble fraction of tumor necrosis factor receptor and serum lipids in overweight patients with type 2 diabetes mellitus. Diabetes Res Clin Pract 2004; 66:133-8. [PMID: 15533580 DOI: 10.1016/j.diabres.2004.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2003] [Revised: 02/27/2004] [Accepted: 03/15/2004] [Indexed: 11/17/2022]
Abstract
AIMS/HYPOTHESIS The UK Prospective Diabetes Study (UKPDS) showed that biguanide therapy in overweight patients reduced the risk for any diabetes-related endpoint and all-cause mortality. Biguanides lower the blood glucose values without stimulation of insulin release. We have investigated the short-term effect of buformin on insulin sensitivity, solved tumor necrosis factor receptors (sTNFRs), and serum lipids in overweight subjects with type 2 diabetes mellitus (DM). METHOD Thirteen overweight subjects with type 2 DM were examined. The subjects who were fed 20 kcal/kg body weight were divided into two subgroups according to whether they were treated by buformin (Buformin group), or dietary therapy alone (Diet group). Six patients were in Buformin group and seven patients were in Diet group. We calculated insulin-mediated glucose uptake by the liver and peripheral tissues using euglycemic hyperinsulinemic clamp combined with an oral glucose load before and after buformin treatment or diet therapy for 2 weeks. RESULTS Fasting plasma glucose, total cholesterol (T-chol), LDL-cholesterol (LDL-chol), and sTNFR2 were significantly decreased, and hepatic glucose uptake significantly increased from 32 +/- 7 to 42 +/- 7% (P < 0.05) in Buformin group but did not changed significantly in Diet group. However, the glucose infusion rate thought to express insulin sensitivity in peripheral tissue, TNF-alpha, sTNFR1, fasting plasma insulin, C-peptide, and NEFA levels did not change significantly in both the groups after treatment. CONCLUSION/INTERPRETATION Buformin improved insulin sensitivity in the liver and decreased T-chol, LDL-chol, and sTNFR2. The mechanism of action for buformin likely involves inhibition of TNF-alpha. Buformin lowers insulin resistance and risk factors for cardiovascular disease including serum lipid and will therefore, be useful in management of overweight type 2 DM patients.
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Affiliation(s)
- S Ohara
- Division of Atherosclerosis and Metabolism, Department of Internal Medicine, National Cardiovascular Center Hospital, Osaka, Japan.
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Bernard V, Pillois X, Dubus I, Benchimol D, Labouyrie JP, Couffinhal T, Coste P, Bonnet J. The -308 G/A tumor necrosis factor-alpha gene dimorphism: a risk factor for unstable angina. Clin Chem Lab Med 2003; 41:511-6. [PMID: 12747595 DOI: 10.1515/cclm.2003.077] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Since the inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) may play a major role in the pathophysiology of acute coronary syndromes, 299 consecutive male patients hospitalized for coronary artery disease (i.e., lumen lost > or = 50%) were genotyped for the functional -308G/A TNF-alpha polymorphism using restriction fragment length polymorphism method, in order to evaluate its potential association with the risk of unstable angina and/or myocardial infarction. A higher frequency of carriers of the A allele was observed in patients with unstable angina (n = 58) when compared to control patients with stable angina (n = 95) (39.66% vs. 23.16% respectively, p = 0.029, odds ratio = 2.2) but not in patients with myocardial infarction (n = 146) (23.97% vs. 23.16%, p = NS). Furthermore, we evidenced an interaction of the polymorphism studied with body mass index in patients with unstable angina. Thus, when stratified analysis was performed, results in patients with a body mass index < or = 27 showed a more striking association between A allele carriage frequency and unstable angina (p = 0.012, odds ratio = 3.0). These results suggest the crucial role of TNF-alpha in the mechanisms responsible for unstable angina in accordance with the concept of vulnerable plaque. On the other hand, mechanisms controlling myocardial infarction appear more complex and heterogeneous.
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Affiliation(s)
- Virginie Bernard
- Institut Fédératif de Recherche no 4 Heart-Lung-Vessel-Thrombosis, Institut National de la Santé et de la Recherche Médicale (U441), Pessac, France
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Plutzky J, Viberti G, Haffner S. Atherosclerosis in type 2 diabetes mellitus and insulin resistance: mechanistic links and therapeutic targets. J Diabetes Complications 2002; 16:401-15. [PMID: 12477625 DOI: 10.1016/s1056-8727(02)00202-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ongoing heavy burden of cardiovascular disease associated with diabetes mellitus highlights the failure of current treatment strategies to address effectively the cardiovascular risk profile in such patients. Insulin resistance is not only an underlying feature in most cases of type 2 diabetes, but is also associated, through the Insulin Resistance Syndrome, with cardiovascular risk factors that promote atherothrombosis through diverse mechanisms. Growing evidence suggests that treatment with anti-diabetic agents that improve insulin sensitivity, such as the thiazolidinediones, improve multiple components of the Insulin Resistance Syndrome, have beneficial effects on various atherothrombotic mechanisms, and reduce atherosclerosis in animal models and perhaps humans as well. Given data implicating chronic inflammation as a central feature of atherosclerosis, the anti-inflammatory activity of the thiazolidinediones may contribute to their potential anti-atherosclerotic effects. An improved understanding of the mechanisms linking diabetes, atherosclerosis, and cardiovascular disease is needed in order to understand how these and other current and emerging therapies might reduce diabetes-associated cardiovascular disease.
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Affiliation(s)
- Jorge Plutzky
- Department of Cardiovascular Medicine, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA.
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Kast RE. Tumor necrosis factor has positive and negative self regulatory feed back cycles centered around cAMP. INTERNATIONAL JOURNAL OF IMMUNOPHARMACOLOGY 2000; 22:1001-6. [PMID: 11090708 DOI: 10.1016/s0192-0561(00)00046-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This paper reviews data that allow recognition of, (1) two opposing intracellular chains of events occurring subsequent to an increase in tumor necrosis factor, TNF, and (2) that these two chains have opposing effects on intracellular cyclic adenosine monophosphate, cAMP. The two chains - attenuation cycle, where TNF results in prostaglandin E mediated increased cAMP and, consequent to this, suppression of TNF levels; and an amplification cycle, where increased TNF increases intracellular cyclic adenosine phosphodiesterase, lowering cAMP, thereby raising TNF levels further. TNF is a central mediator in several inflammatory diseases. Understanding TNF control systems will allow better delineation of pathophysiology and clinical care.
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