From the Guidelines
Oxidative stress is defined as the tissue damage resulting from the imbalance between an excessive generation of oxidant compounds and antioxidant defense mechanisms. This imbalance can lead to cell and tissue injury, and is a key contributor to various diseases, including cardiovascular disease, as noted in the K/DOQI clinical practice guidelines for cardiovascular disease in dialysis patients 1.
Key Points
- Oxidative stress represents part of the defense mechanisms against invading micro-organisms and malignant cells, as well as a signal for tissue healing and remodeling 1.
- The generation of oxidative compounds is an important mechanism of normal physiology, playing a role in both inflammation and tissue repair processes 1.
- Chronic activation of oxidative processes may contribute to cell and tissue injury, and several deficiencies in different components of antioxidant defense mechanisms have been demonstrated in chronic kidney disease (CKD), including reduced levels of vitamin C and vitamin E, and deficiency in the glutathione scavenging system 1.
- Oxidative stress occurs when the production of oxidants exceeds local anti-oxidant capacity, and the prevention of the harmful effects of reactive oxygen systems—by both enzymatic and nonenzymatic antioxidant systems—are of major importance 1. Some lipids, proteins, carbohydrates, and nucleic acids are modified by oxy-radicals and have lifetimes ranging from hours to weeks, and may serve as clinical surrogate markers of oxidative stress 1.
From the Research
Definition of Oxidative Stress
- Oxidative stress is a phenomenon caused by an imbalance between the production and accumulation of oxygen reactive species (ROS) in cells and tissues and the ability of a biological system to detoxify these reactive products 2.
- It is defined by an imbalance between increased levels of reactive oxygen species (ROS) and a low activity of antioxidant mechanisms 3.
- Oxidative stress happens when the free radicals production exceeds the capacity of the antioxidant system in the body's cells 4.
Causes of Oxidative Stress
- Environmental stressors such as UV, ionizing radiations, pollutants, and heavy metals contribute to greatly increase ROS production, leading to oxidative stress 2.
- Xenobiotics, such as antiblastic drugs, also contribute to the increase in ROS production 2.
- Endogenous and exogenous sources of reactive oxygen species can lead to oxidative stress 4.
Effects of Oxidative Stress
- Oxidative stress can induce damage to the cellular structure and potentially destroy tissues 3.
- It is implicated in various pathological conditions, including cancer, neurodegenerative diseases, cardiovascular diseases, diabetes, inflammatory diseases, and intoxications 3.
- Oxidative stress is a component of numerous diseases, including diabetes mellitus, atherosclerosis, cardiovascular disease, Alzheimer's disease, Parkinson's disease, and cancer 4.
Role of Antioxidants
- Antioxidants can contribute to facing oxidative stress 5.
- Synthetic antioxidants must be provided from external sources to supplement the antioxidant defense mechanism internally 6.
- Natural antioxidants, such as flavonoids, polyphenols, and glutathione, along with some vitamins, have been reported to possess strong antioxidant activities in vivo and in vitro studies 6.