Diabetes and Antioxidants: Myth or Reality? (original) (raw)

The Role of Oxidative Stress and Antioxidants in Diabetic Complications

Sultan Qaboos University Medical Journal, 2012

Diabetes is considered to be one of the most common chronic diseases worldwide. There is a growing scientific and public interest in connecting oxidative stress with a variety of pathological conditions including diabetes mellitus (DM) as well as other human diseases. Previous experimental and clinical studies report that oxidative stress plays a major role in the pathogenesis and development of complications of both types of DM. However, the exact mechanism by which oxidative stress could contribute to and accelerate the development of complications in diabetic mellitus is only partly known and remains to be clarified. On the one hand, hyperglycemia induces free radicals; on the other hand, it impairs the endogenous antioxidant defense system in patients with diabetes. Endogenous antioxidant defense mechanisms include both enzymatic and non-enzymatic pathways. Their functions in human cells are to counterbalance toxic reactive oxygen species (ROS). Common antioxidants include the vitamins A, C, and E, glutathione (GSH), and the enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GRx). This review describes the importance of endogenous antioxidant defense systems, their relationship to several pathophysiological processes and their possible therapeutic implications in vivo.

The Role of Antioxidants on Oxidative Stress in Diabetes Mellitus

Journal of Pharmacy Technology, 2010

Many patients use dietary supplements, including vitamins, minerals, and herbal products, on a daily basis to improve their health. Pharmacists can educate patients about the proper use of dietary supplements and the role of these supplements on their health.

Oxidative Stress and Diabetes: An Overview

Asian Journal of Pharmaceutical and Clinical Research, 2015

Oxidative stress is well known to be involved in the pathogenesis of lifestyle related diseases. Oxidative stress contributes to many pathological conditions including cancer, asthma, atherosclerosis, hypertension, and diabetes. It is a state in which oxidation exceeds the antioxidant systems in the body secondary to a loss of balance between them. Reactive oxygen species (ROS) are produced from molecular oxygen as a result of normal cellular metabolism and environmental factors such as air pollutants, cigarette smoke and sedentary lifestyle. ROS are highly reactive molecules that can damage carbohydrates, nucleic acids, lipids and proteins. There is considerable evidence that induction of oxidative stress is a key process in the onset of diabetes. Lipid peroxidation owing to free radical activity plays an important role in complications of diabetes. Increased levels of lipid peroxidation are a consequence of free radical activity in both Type 1 and Type 2 diabetes. The human body has several mechanisms to counter the effects of these reactive species by the production of antioxidant enzymes like glutathione and catalase. Antioxidants can also be taken exogenously through the diet. In this review article, we summarize the effect of oxidative stress in the development of diabetes.

Diabetes mellitus and oxidative stress––A concise review

Human body is continuously exposed to different types of agents that results in the production of reactive species called as free radicals (ROS/RNS) which by the transfer of their free unpaired electron causes the oxidation of cellular machinery. In order to encounter the deleterious effects of such species, body has got endogenous antioxidant systems or it obtains exogenous antioxidants from diet that neutralizes such species and keeps the homeostasis of body. Any imbalance between the RS and antioxidants leads to produce a condition known as ''oxidative stress'' that results in the development of pathological condition among which one is diabetes. Most of the studies reveal the inference of oxidative stress in diabetes pathogenesis by the alteration in enzymatic systems, lipid peroxidation, impaired Glutathione metabolism and decreased Vitamin C levels. Lipids, proteins, DNA damage, Glutathione, catalane and superoxide dismutase are various biomarkers of oxidative stress in diabetes mellitus. Oxidative stress induced complications of diabetes may include stroke, neuropathy, retinopathy and nephropathy. The basic aim of this review was to summarize the basics of oxidative stress in diabetes mellitus. ª 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The sources and the targets of oxidative stress in the etiology of diabetic complications

Romanian J …, 2007

Oxidative stress, defined as an imbalance between reactive oxygen species production and breakdown by endogenous antioxidants, is closely associated with aging and a number of diseases including inflammation, carcinogenesis, and atherosclerosis. Also, it has been shown that oxidative stress plays a role in the progression of diabetes. Hyperglycemia, which occurs during diabetes (both type 1 and type 2) and, to a lesser extent, during insulin resistance, causes oxidative stress. Oxidative stress may be important in diabetes, not just because of its role in the development of complications, but because persistent hyperglycemia, secondary to insulin resistance, may induce oxidative stress and contribute to beta cell destruction in type 2 diabetes. Glucose control plays an important role in the prooxidant/antioxidant balance. A supplementation with antioxidants has been proposed as a complementary treatment, and some antidiabetic agents may by themselves have antioxidant properties independently of their role on glucose control. The aim of this paper was to review the sources and the targets of oxidative stress in the etiology of diabetic complications.

ROLE OF OXIDATIVE STRESS IN PATHOGENESIS OF DIABETES AND ITS COMPLICATIONS

Pharmacologyonline, 2011

This review article is comprised of pathogenesis and role of free radicals and oxidative stress in progression of diabetes and diabetic complications. Reactive oxygen species are formed disproportionately in diabetes by glucose autooxidation, impaired polyol pathway, nonenzymatic glycation of proteins, and the subsequent oxidative degradation of glycated proteins. Abnormally high levels of free radicals and the simultaneous decline of antioxidant defense mechanisms can lead to damage cell structures, including lipids and membranes, proteins, DNA, increased lipid peroxidation, and development of insulin resistance. It has been suggested that enhanced production of free radicals and oxidative stress is central event to the development of diabetic complications. Changes in oxidative stress biomarkers including superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, glutathione levels, vitamins, lipid peroxidation, nitrite concentration, nonenzymatic glycosylated proteins, and hyperglycemia play major role in the pathogenesis of both types of diabetes mellitus as well as diabetic complications including diabetic neuropathy, diabetic nephropathy, diabetic retinopathy, dyslipidemia, coronary heart disease, diabetic foot ulcer, diabetic ketoacidosis and peripheral vascular diseases. Antioxidants, capable of neutralizing free radicals or their actions, act at different stages. They act at the levels of prevention, interception and repair caused by free radical induced cell damage.

The Role of Oxidative Stress in Diabetes Mellitus: A 24-year Review

2014

Background: Diabetes mellitus is a widespread and devastating disease. Diabetes is associated with several mechanisms of tissue damage, one of which is oxidative stress. Oxidative stress and oxidative damage to tissues are common end points to chronic diseases such as atherosclerosis, diabetes and cardiovascular diseases. Oxidative stress plays an important role in the pathogenesis of and the complications of diabetes. Hyperglycaemia results in overproduction of oxygen free radicals which contributes to the progression of diabetes. Objective: This review aims at determining the role of oxidative stress in diabetes and diabetic complications. Method: Relevant literatures were reviewed from medical journals, library search, Pub Med search, Google search and other internet search engines (Google Scholar, Hinarii, Ask.com) from 1987 to 2011. Results: Several studies demonstrated that oxidative stress plays a role in the progression of diabetes and also in the development and progression...

OXIDATIVE STRESS, ANTIOXIDANT SCAVENGING SYSTEMS AND DIABETES MELLITUS: A CONCISE REVIEW

The enormous majority of complex life on earth requires oxygen for its survival. Oxygen is an extremely reactive molecule that damages living organisms by producing reactive oxygen species leading to oxidative stress. Oxidative stress arrived from increasing amount of ROS or as a consequence of increased levels of lipid peroxides and free-radical intermediates, as well as the reduced total antioxidant capacity that may cause the reduction of molecular oxygen or oxidation of water to leads to the formation of free radicals that could damage cellular lipids, membranes, proteins and DNA (Rains et al, 2011). Living organisms have a complex network of antioxidant metabolites and enzymes that work mutually to prevent oxidative damage to cellular components Ido et al, 1997). Advanced oxidative stress and alterations in antioxidant potential, observed in both clinical and investigational diabetes mellitus. Alteration in oxidative stress biomarkers, including Catalase, superoxide dismutase, glutathione, glutathione reductase, glutathione peroxidase, antioxidant vitamins, lipid peroxidation, non enzymatic glycosylated proteins, are helpful in identifying the risk of developing vascular complications in diabetics.

Diabetic Complications and Oxidative Stress: A 20-Year Voyage Back in Time and Back to the Future

Antioxidants

Twenty years have passed since Brownlee and colleagues proposed a single unifying mechanism for diabetic complications, introducing a turning point in this field of research. For the first time, reactive oxygen species (ROS) were identified as the causal link between hyperglycemia and four seemingly independent pathways that are involved in the pathogenesis of diabetes-associated vascular disease. Before and after this milestone in diabetes research, hundreds of articles describe a role for ROS, but the failure of clinical trials to demonstrate antioxidant benefits and some recent experimental studies showing that ROS are dispensable for the pathogenesis of diabetic complications call for time to reflect. This twenty-year journey focuses on the most relevant literature regarding the main sources of ROS generation in diabetes and their role in the pathogenesis of cell dysfunction and diabetic complications. To identify future research directions, this review discusses the evidence in...