Antioxidant protection in patients with pulmonary tuberculosis

Abstract

The literature review summarizes the data on the classification and characteristics of the antioxidant defense system. This model combines a number of different substances. Each of the components of the antioxidant system acts in close connection with its other structural elements, harmoniously complements, and in many cases – enhances the action of each other. The functional basis of the system of antioxidant protection is formed by the glutathione system, the constituent elements of which are actually glutathione and enzymes that catalyze the reactions of its reverse transformation (oxidation ↔ reduction). Most researchers conventionally divide the system of antioxidant protection into enzymatic and non-enzymatic. The enzyme links of the antioxidant defense system include: catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione transferase and other enzymes. The non-enzymatic system includes fat-soluble vitamins A, E and K, water-soluble vitamins C and PP, biogenic amines, glutathione, carotenoids, ubiquinone, sterols. Both enzymatic and non-enzymatic antioxidant defense systems are present in the bloodstream. The activity of the enzymatic antioxidant system is very well regulated and depends on age, physiological condition, hormone dynamics, intensity of antioxidant enzyme synthesis, pH, presence of coenzymes, inhibitors, activators and other factors. The non-enzymatic part of the antioxidant system does not require as many regulators as the chemical itself - the antioxidant - reacts chemically with the radical. Only the reaction rate can change. The lungs are directly exposed to oxygen and oxidants of polluted air, they are most sensitive to oxidative damage, so they have an increased possibility of free radical reactions. Protection against the damaging effects of reactive oxygen species and free radicals is provided by anti-radical protective systems, especially the glutathione system and its enzymes. Numerous papers have obtained clinical and experimental data on the important role of free radical oxidation of lipids (FROL) and antioxidant systems (AOS) protection in the development of many diseases, including pulmonary tuberculosis (TB). The review presents modern views on the state of the system of lipid peroxidation (LPO) and antioxidant protection in TB. The main topic of the review is information on the generation of free radical compounds by different populations of leukocytes with further enhancement of LPO and secondary deepening of functional disorders. The article substantiates the feasibility of identifying LPO products as non-specific markers of aseptic inflammation in TB and the need to develop new generations of antioxidants. One of the universal mechanisms of damage to cell membranes is LPO, the excessive activation of which is normally prevented by factors of the antioxidant defense system. Membrane-bound enzymes involved in the formation of LPO products include lipoxy and cyclooxygenases. Lipoperoxidation processes change the structure and phospholipid composition of cell membranes, which negatively affects the cellular immune response due to damage to the mechanisms of information transfer from extracellular regulators to intracellular effector systems.