1. Investigación

Due to medical advances and lifestyle changes, population life expectancy has increased. For this reason, it is important to achieve healthy aging by reducing the risk factors causing damage and pathologies associated with age. Through nutrition, one of the pillars of health, we are able to modify these factors through modulation of the intestinal microbiota. The Mediterranean and Oriental diets are proof of this, as well as the components present in them, such as fiber and polyphenols. These generate beneficial e ects on the body thanks, in part, to their interaction with intestinal bacteria. Likewise, the low consumption of products with high fat content favors the state of the microbiota, contributing to the maintenance of good health.

Hyperglycemia, a defining characteristic of diabetes, combined with oxidative stress, results in the formation of advanced glycation end products (AGEs). AGEs are toxic compounds that have adverse e ects on many tissues including the retina and lens. AGEs promote the formation of reactive oxygen species (ROS), which, in turn, boost the production of AGEs, resulting in positive feedback loops, a vicious cycle that compromises tissue fitness. Oxidative stress and the accumulation of AGEs are etiologically associated with the pathogenesis of multiple diseases including diabetic retinopathy (DR). DR is a devastating microvascular complication of diabetes mellitus and the leading cause of blindness in working-age adults. The onset and development of DR is multifactorial. Lowering AGEs accumulation may represent a potential therapeutic approach to slow this sight-threatening diabetic complication. To set DR in a physiological context, in this review we first describe relations between oxidative stress, formation of AGEs, and aging in several tissues of the eye, each of which is associated with a major age-related eye pathology. We summarize mechanisms of AGEs generation and anti-AGEs detoxifying systems. We specifically feature the potential of the glyoxalase system in the retina in the prevention of AGEs-associated damage linked to DR. We provide a comparative analysis of glyoxalase activity in di erent tissues from wild-type mice, supporting a major role for the glyoxalase system in the detoxification of AGEs in the retina, and present the manipulation of this system as a therapeutic strategy to prevent the onset of DR.

Glucose and insulin relationship with aging were studied in fed rats. Levels of basal circulating glucose did not change while those of RIA-insulin increa!ed and RIA-glucagon decreased lincary with animal weight. The oral glucose tolerance test revealed a greater increase in blood glucose in adult and old rats than in prepubcrals, while the rise in plasma insulin was faster and greater in the oldest group. After intravenous glucose load, plasma insulin increase was greater in adult than in prepuberal and old rats, and in the latter group values remained elevated for a longer period. The hypoglycemic response to i.v. insulin was greatest in the prepuberals with no difference between adult and old rats. In prepuberals, the augmented insulin sensitivity was counteracted by retarded msulinotropic glucose action and an enhanced basal glucagon level, while in the old animals normoglycemia was maintained due to an augmented secretory response of B cells. counteracted by reduced sensitivity to endogenous insulin.

Free radicals generated as byproducts of normal metabolism can damage biologically relevant molecules. When their generation is increased, damage can also be increased, resulting in the development of many pathological cinditions. Antioxidant defenses protect the body from the detrimental effects of free radicals. Dietary fruits and vegetables provide a reasonable amount of compounds that act as physiological antioxidants. Although existing knowledge does not allow a final and conclusive assessment of the relevance of antioxidants for health, is does aspects of antioxidant supplementation in health and disease.