Presentacion

INTRODUCTION One of the most important problems in modern gerontology is the development of means to extend healthy lifespan. Recently, a number of nutrients and chemicals have been widely advertised as anti-aging drugs or supplements. Experimental studies have repeatedly shown the life-extending effect of such substances, often referred to as life-span prolonging drugs or geroprotectors [1]. The life-extending capacity was shown for a number of geroprotectors, including antioxidants, chelate agents and lathyrogens, succinate, adaptogens and herbs, neurotropic drugs, inhibitors of monoamine oxidase, glucocorticoids, dehydroepiandrosterone, sex and growth hormones, melatonin, pineal peptide preparations, protein inhibitors, antidiabetic biguanides, thymic hormones and peptides, immunomodulators and enterosorbents [2], mimetics of superoxide dismutase and catalase [3]. The natural and synthetic dietary supplements and chemicals including antioxidants, vitamins and hormones are among the most popular products on the market, even without solid scientific evidence [4]. However, excessive intake of antioxidants or hormones is known to destroy delicate control mechanisms of homeostatic balance. It is therefore unlikely that they have a long-term beneficial impact [5]. Currently, there are no authentic anti-aging pharmaceuticals. However, this does not mean that they cannot exist [6]. One reason none has been found is that no assay has existed for identifying such drugs. Historically, the only accepted method of evaluating therapies that attempt to slow aging and the onset of age-related diseases has been lifespan studies. However, life extension per se hardly can be considered as strong evidence for a real anti-aging action of the used compound. Life-extending effects were found for a number of obviously harmful substances like DDT and nuclear fallout. These effects are assumed to be caused by hormesis [7]. Hormesis is the concept that mild stimulation that is harmful at high doses can up-regulate physiological/biochemical processes in the body to produce an adaptive beneficial response at lower doses [8]. Chemical hormesis was observed in a wide range of taxonomic groups and involved agents representing highly diverse chemical classes [9]. In experimental studies, chemical hormesis was repeatedly exhibited by feeding of antibiotics, herbicides, pesticides, insecticides, hydrocarbons, ethanol, solvents and several other classes of chemicals in various organisms, including plants, viruses, bacteria, fungi, insects, fish, birds, rodents and primates [10]. For gerontologists, most important are the survival-enhancing aspects of hormesis. Several mild stresses including irradiation, heat and cold shock, hypergravity, exercise, etc. have been reported to increase life span [11]. Longevity hormesis has been obtained by dietary supplementation with antibiotics, herbicides, pesticides, heavy metals and hydrocarbons [7].