Some Current Insights into Oxidative Stress

Oxidative stress is a phenomenon associated with pathogeneticmechanisms of several diseases including atherosclerosis,neurodegenerative diseases, such as Alzheimer’s and Parkinson’sdisease, cancer, diabetes mellitus, inflammatory diseases, as wellas psychological diseases or aging processes. Oxidative stress isdefined as an imbalance between production of free radicals andreactive metabolites, so-called oxidants, and their elimination byprotective mechanisms, referred to as antioxidative systems. Thisimbalance leads to damage of important biomolecules andorgans with potential impact on the whole organism. Oxidativeand antioxidative processes are associated with electron transferinfluencing the redox state of cells and the organism. Thechanged redox state stimulates or inhibits activities of varioussignal proteins, resulting in a changed ability of signal pathwaysto influence the fate of cells. At present, the opinion thatoxidative stress is not always harmful, has been accepted.Depending on the type of oxidants, intensity and time of redoximbalance as well as on the type of cells, oxidative stress canplay a role in the regulation of other important processes throughmodulation of signal pathways, influencing synthesis ofantioxidant enzymes, repair processes, inflammation, apoptosisand cell proliferation, and thus processes of malignity. Imprudentadministration of antioxidants may therefore have a negativeimpact on the organism.