DefinitionHow does oxidative stress occur?
The term oxidative stress was first used by Helmut Sies in 1985 and describes a metabolic state characterized by an excess of reactive oxygen compounds (ROS). These are produced in every cell in the so-called mitochondria, in which cellular respiration takes place to produce energy. During the metabolic processes in the mitochondria, various reactive oxygen compounds can be produced, such as hydrogen peroxide, hydroxyl radicals or superoxide anion radicals.
These substances are, according to their name, extremely reactive and interact with many other components of a cell. These processes are described as oxidation. In a healthy cell, the oxidizing substances, such as ROS, are in equilibrium with reducing substances, which ultimately leads to a neutralization of their harmful effects. If this balance is shifted in favor of the reactive oxygen compounds, cell damage occurs. This process is known as oxidative stress.
Causes
The causes for a shift in this balance in the sense of oxidative stress can have various causes. In addition to external factors, such as too much UV radiation or pollution of the air, an unhealthy diet and the consumption of alcohol or nicotine can also trigger oxidative stress. All these triggers are the same, whether the body converts more energy to neutralize toxins or a simple oversupply in an unhealthy diet.
This increased energy conversion then results in an increased production of reactive oxygen compounds. Similarly high increases in energy turnover can also be triggered by an active immune defence in the presence of an infection or inflammation, or by extreme sports. The influence of drugs in the development of oxidative stress is also increasingly being discussed. Certain antibiotics and hormone preparations are suspected in particular.
How can oxidative stress be diagnosed?
The diagnosis of oxidative stress is based on 3 different pillars. First of all, a detailed patient history is taken, which includes the examination of various risk factors, such as an unhealthy diet, the consumption of alcohol or nicotine and many more. This is followed by a physical examination with determination of weight and BMI, as well as a vascular check based on pulse controls.
Blood pressure and heart rate are also measured. In the meantime, a very precise measurement of oxidative stress can be carried out by combining various laboratory parameters. The most accurate measurement has been the measurement of proteins that are produced as a result of oxidative stress.
The most important of these are malondialdehyde-modified LDL, a form of cholesterol, and nitrotyrosine. Their accuracy is mainly due to the fact that they are only subject to very small fluctuations, as is the case with the determination of enzymes, for example. In addition to the testing of proteins produced as a result of reactive oxygen compounds, their actual counterparts of the reducing system can also be measured.
These should be significantly reduced in the case of pronounced oxidative stress. Vitamin C and E as well as intracellular glutathione belong to this group. In most cases, trace elements such as selenium or zinc are also determined, as they are an integral part of many enzymes that are active in this context.
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