Aging chronic diseases, free radical

Free Radical Involvement in Chronic Diseases and Aging... 

Oxidation of cellular components by reactive oxygen species (ROS) and free radicals is involved in a variety of serious acute and chronic diseases inflammation [56], ischemia-reperfusion damage [57,58], limg disease [59], kidney damage [60], atherosclerosis, diabetes, allergies, cancer and aging [61]. 

Free radicals are not just esoteric reactants they are the agents of cell death and destruction. They are involved in all chronic disease states (e.g., coronary artery disease, diabetes mellitus, arthritis, and emphysema) as well as acute injury (e.g., radiation, strokes, myocardial infarction, and spinal cord injury). Through free radical defense mechanisms in our cells, we can often restrict the damage attributed to the "normal" aging process. 

Nicotine, the major alkaloid fotmd in tobacco plant leaves and the prototypical nicotinic acetylcholine receptor (nAChR) agonist, is known to reduce memory impairment associated with chronic stress [1-3], aging [4—8], brain lesions [9], and cognitive disorders, including Alzheimer s disease (AD) [3, 10-14], schizophrenia [14], attention deficit/hyperactivity disorder (ADHD) [15,16], Parkinson s disease [13, 17], post-traumatic stress disorder (PTSD) [18], sleep deprivation [19, 20], and hypothyroidism [21, 22], Moreover, nicotine is a potent scavenger of hydroxyl and superoxide free radicals. In fact, it has been reported that nicotine is more of an antioxidant than vitamin C [23]. 

When produced in excess, free radicals and oxidants generate a phenomenon called oxidative stress, a deleterious process that can seriously alter the ceU membranes and other structures such as proteins, lipids, lipoproteins and deoxyribonucleic acid (Betteridge 2000). If not regulated properly, oxidative stress can induce a variety of chronic and degenerative diseases such as Alzheimer s disease, atherosclerosis, emphysema, hemochromatosis, many forms of cancer (e.g. melanoma, Parkinson s disease and schizophrenia) as well as the ageing process (Fig. 4.2) (Sangameswaran et al. 2008 Sachindra et al. 2010). 

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