Real importance of oxidants and antioxidants - New measurement methods developed

Real importance of oxidants and antioxidants - New measurement methods developed

New processes provide insights into the body's own oxidants
The state of oxidation in the organism is closely related to nutrition, physical activity, infections, cancer and possibly also aging, according to the current report by the German Cancer Research Center (DKFZ) in Heidelberg. Scientists at the DKFZ have developed two new biological measuring systems with which disease-relevant changes in the oxidation state of the cells can be better analyzed.

According to the researchers, there are “a lot of errors and myths surrounding the importance of oxidants and antioxidants for human health.” The oxidants are traditionally considered to have a harmful effect, while antioxidants are considered to be health-promoting. "But researchers have known for many years that the body's own oxidants as essential messengers help to maintain the functions of the organism," reports the DKFZ. According to the experts, the type and amount as well as the spatial and temporal concentration of the oxidants decide on the effect. "This is why we are interested in which cells and tissues produce which oxidants in which situation and for how long in the context of the entire organism," says cell biologist Tobias Dick from the DKFZ.

Oxidation state so far difficult to measure
The exact determination of the oxidation state is of particular interest to medical professionals in view of the connection with various diseases. According to the DKFZ, the development of luminous biosensors, which the work group led by Tobias Dick had already achieved a few years ago, was "an important step in researching the body's own oxidants." and the light signals emitted by the sensors indicated the presence of certain oxidants - "in real time and precisely to the individual cell," reports the DKFZ. However, the medical benefit has so far been limited, since the light signals can only penetrate the tissue at a short distance. According to the researchers, the use of such sensors has so far been concentrated on small or transparent organisms. For example, the sensors are particularly well applicable to fruit flies or zebra fish. However, the sensors were less suitable for use in mice, which form an important model organism in medical research.

Distribution of oxidants made visible
However, the research team led by Tobias Dick has now succeeded in solving the difficulties in detecting the biosensor by permanently preserving its condition in the removed tissue. The scientists use a special combination of cold and chemical treatment for this. "In this way, the spatial distribution of the oxidants could be made visible on a fixed tissue section, just as it corresponds to the distribution in the living organism," reports the DKFZ. The results of the researchers were published in the journal "Science Signaling". In the article, the scientists describe as examples the distribution of oxidants in a growing tumor, the reaction of the liver to inflammation and the reaction of muscle fibers to hunger. "With the new method, the researchers now want to study the influence of diseases and active substances on the distribution of oxidants throughout the body," the DKFZ said.

Real-time measurement of the level of oxidants
In a second study, the scientists led by Tobias Dick devoted themselves to improving the sensitivity of the biosensors in order to visualize "the smallest metabolic fluctuations in the production of oxidants, such as occur, for example, when changing diet or during physical activity". For this purpose, they developed a biosensor based on the so-called peroxiredoxins, which are known as proteins with the highest sensitivity to hydrogen peroxide. The scientists report that the new sensors are designed to be highly sensitive to the smallest increase or decrease in the level of oxidants. According to the DKFZ, a test of the sensors in yeast cells "even tracked the movement of oxidants between individual structures within the cell." The second study was published in the journal "Nature Chemical Biology". The next goal is to bring the two new developments together, for example to investigate how a minimally changed production of oxidants is related to the development of metabolic diseases. (fp)

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