Human Physiology, Vol

Based on an analysis of current literature, this work deals with mechanisms of intoxication and detoxication during the aging process, as well as prospects for applying enterosorption as a detoxication technique for prolonging life. Enterosorption belongs to scientific field in which Russian researchers are ahead of others. Therefore, the most interesting results have been obtained by them (including researchers from the Commonwealth of Independent States (CIS)). These results generally concern clinics. Currently, information on the possible use of enterosorbents to prolong life has been accumulated. It would be beneficial to review the scientific works published over the past decades in an effort to elucidate the mechanism of enterosorbents' action, and the advantages and limitations of this method as a tool for slowing the aging process. INTOXICATION AND AGING Intoxication of the organism always accompanies aging. I.I. Mechnikov long ago considered selfintoxication due to the toxic effects of endogenous and exogenous toxins produced by large intestinal microflora as a main factor causing the disintegration of intertissue relations, which in turn causes aging. The most effective factors that decelerate aging are hypothermia and a low-calorie diet. It is assumed that these factors decrease the proportion of sideeffects, such as nonenzymatic reactions, which significantly contribute to organism intoxication, resulting in acceleration of aging [1, 2]. Intoxication is closely associated with agedependent alterations in the genome and cellular metabolism, including the effects of free-radical reactions, when considering the whole organism, generally with all systems of organs and tissues, particularly with the aging of the liver, kidneys, and gastrointestinal tract. Liver plays an important role in protein, lipid, and carbohydrate metabolism and in holopoiesis, bile secretion, and detoxication; therefore, it significantly affects the maintenance of homeostasis. During aging, a decrease in the hepatocyte number, an increase in the number of polyploid cells, a decrease in the number of mitochondria per cell, a decrease in protein synthesis (particularly in mitochondrial activity), a decrease in respiratory phosphorylation and an increase in oxidative phosphorylation, an extension of the lag-time, and a decrease in inductive (adaptive) protein synthesis occur, accompanied by an earlier onset of cachexia, and probably leading to disorders of the liver system functions, including detoxication [3]. Urinary and biliary excretion of xenobiotic metabolites decreases significantly during aging, which results from the decrease in detoxication intensity. The microsomal oxidative system plays a substantial role in liver detoxication. It was observed that the activities of certain enzymes in the microsomal oxidative system remain unchanged with time, whereas their inductive properties decelerate in parallel with the decrease in response intensity [3]. Kidneys are a vital organ for homeostasis maintenance. The twin organ significantly changes during aging. From the period of embryonal life, the degradation of the nephrons proceeds, characterized by a loss of about 1/3 to 1/2 of the functional units to senility, progressive shunting of the renal blood vessels, an increase in circulatory system resistance (compared with resistance of the total vessel bed), and a decrease in total ATP-ase activity. All these changes lead to an age-related deficit in the main kidney functions due to a decrease in the mean rate of blood flow and glomerular filtration and, furthermore, to a drop in nitrogen excretion. The above-mentioned, combined with an age-specific enhancement of the relative contribution of the humoral compared to the nervous regulation determine the increase in both latent and regenerative periods in the renal response to stress [4]. The gastrointestinal tract has a distinctive function in metabolic relations between the organism and the environment. Digestion, the absorption of nutrients, and coupled processes of discharge occur here. During aging, the cells covering the gastrointestinal epithelium are characterized by a progressive decline in proliferative activity and disturbance of differentiation, which leads to a decrease in the number of enterocytes and main and delomorphous cells, and a reduction in surface and thickness of mucous membrane. With age (from 30-40 years), the volumes of gastrointestinal secretion significantly decrease and, furthermore, the ratios of components and quality of digestive juice are distorted. The age-related ENTEROSORPTION AS A METHOD FOR PROLONGING LIFE 381 involution of the small intestinal mucous membrane is accompanied by a decrease in the oxidation level of enterocytes, a decrease in the number and length of microvilli, and a change in glycocalix. This determines disorders in both membrane digestion and absorption of peptides, lipids, and, to a lesser extent, carbohydrates, and additionally, vitamins and macroelements. It is known that aging is closely connected with a deceleration of the intestinal evacuator function. All the above-mentioned changes in the digestive tract provide the preconditions for quantitative and qualitative shifts in the microflora of the gastrointestinal tube. With the onset of senility, the amount of lactic acid bacteria decreases, whereas the relative portion of putrefactive, pus-producing bacteria, as well as the amount of atypical strains with pathogenic and opportunistic properties, increases against a background of significant growth in the total biomass. Furthermore, changes in the normal relations of cavitary and mucous components of microflora occur [5]. The alimentary canal, kidneys, and liver are the main structures involved in the detoxication processes, but, during aging, even with a slight detoxication insufficiency of these organs, their reactive properties are significantly deteriorated. This is aggravated by agespecific changes in other body systems, mainly in the cardiovascular and neurohumoral systems, which leads to an increase in the frequency of intoxication and to deceleration of the detoxication processes.