Investigation of oxidative stress in ageing and certain diseases

The mechanism of oxidative stress was described for the first time by the American Denham Harman in his free radical theory of ageing. He also highlighted the antioxidant role of vitamins C and E and beta carotene. According to this theory, highly reactive molecules are constantly reacting with crucial molecules in our bodies, causing them to deteriorate. This ultimately leads not only to ageing, but also to various diseases. These highly reactive molecules are called free radicals or reactive oxygen species (ROS).

These ROS are necessary for important biological functions and are involved in particular in cell signalling pathways. However, when they are present in excess amounts in certain situations such as stress, smoking, alcoholism, obesity, poorly managed physical exercise, etc., they can interact with different cellular components, such as DNA, proteins and lipids, and can thus cause various chronic and acute diseases such as cataracts, cancer, coronary heart disease, diabetes, renal failure, Alzheimer’s disease and Parkinson’s disease, as well as sterility.

In theory, these ROS are neutralised or managed by protective mechanisms in the body called antioxidants. Antioxidants are a group of various kinds of molecule (enzymes, proteins, trace elements, etc.) which are produced by the body but also introduced into the body through our diet. These molecules interact with each other (enzymes, coenzymes, cofactors) to limit oxidative stress.
Examples of antioxidants: vitamins C and E, carotenoids, polyphenols, zinc, selenium, and glutathione reductase.

However, in disease states, the antioxidant protection systems are often overwhelmed. This is what is called oxidative stress. Put simply, oxidative stress is the imbalance between the production of ROS and the ability of the body to neutralise these toxic compounds, leading to an excess of aggressive free radicals as compared to protective natural antioxidants. This plays a role in inflammation and mutagenesis, promoting ageing and also playing a role in the aetiology of many diseases.

Treatment of oxidative stress is justified in several contexts:

• Within a context of prophylaxis (cardiovascular diseases, neurodegenerative diseases, ageing, etc.). Numerous cohort studies have demonstrated the efficacy of antioxidant therapy in the prevention of disease (for example the SUVIMAX study).
•  Within a context of monitoring; use as an indicator of the health of the patient.

Analysis of oxidative stress does not provide information about a specific pathology in a patient. Instead, it evaluates the condition of the patient and provides information on their ability to fight a disease.