Sulfur-containing antioxidants increase in vitro several functions of lymphocytes from mice.

The in vitro effects of several sulfur-containing antioxidants, such as glutathione (GSH), N-acetylcysteine (NAC), thioproline (TP) and taurine (TAU), at different concentrations, on key functions of lymphocytes from axillary nodes, spleen, thymus and peritoneum from young-adult BALB/c mice have been investigated. The functions studied have been proliferation, both spontaneous and in response to the mitogen Concanavalin A, mobility both spontaneous and directed to a chemical attractant (chemotaxis) and adherence to substrate. The effect of these antioxidants on the viability of leukocytes was also investigated. The results show an antioxidant-induced stimulation of all the functions studied. The highest concentrations used of each antioxidant were the most effective in proliferation (5mM for GSH, 1mM for TP and NAC and 40 mM for TAU). These concentrations increase mobility significantly. The presence of TP+NAC enhances the chemotaxis of peritoneal lymphocytes more than each antioxidant separately. The adherence capacity of peritoneal lymphocytes also increased at 10 min of incubation with GSH, TP and NAC. All these antioxidants increase the viability of leukocytes in culture, especially in cells from spleen. In conclusion, the sulfur-containing antioxidants studied in vitro improve the functional capacity of lymphocytes from young-adult mice and these results showing that the improvement of the immune response, and specifically of the lymphocyte functions, found after ingesting diet supplemented with the antioxidants studied, are due to a direct action of these compounds in the immune cells.

An update of the oxidation-inflammation theory of aging: the involvement of the immune system in oxi-inflamm-aging.

The aging process is one of the best examples of the effects of a deterioration of homeostasis, since aging is accompanied by an impairment of the physiological systems including the homeostatic systems such as the immune system. We propose an integrative theory of aging providing answers to the how (oxidation), where first (mitochondria of differentiated cells) and why (pleiotropic genes) this process occurs. In agreement with this oxidation-mitochondrial theory of aging, we have observed that the age-related changes of immune functions have as their basis an oxidative and inflammatory stress situation, which has among its intracellular mechanisms the activation of NFkappaB in immune cells. Moreover, we have also observed that several functions of immune cells are good markers of biological age and predictors of longevity. Based on the above we have proposed the theory of oxidation-inflammation as the main cause of aging. Accordingly, the chronic oxidative stress that appears with age affects all cells and especially those of the regulatory systems, such as the nervous, endocrine and immune systems and the communication between them. This fact prevents an adequate homeostasis and, therefore, the preservation of health. We have also proposed a key involvement of the immune system in the aging process of the organism, concretely in the rate of aging, since there is a relation between the redox state and functional capacity of the immune cells and the longevity of individuals. Moreover, the role of the immune system in senescence could be of universal application. A confirmation of the central role of the immune system in oxi-inflamm-aging is that the administration of adequate amounts of antioxidants in the diet, improves the immune functions, decreasing their oxidative stress, and consequently increases the longevity of the subjects.

A model of premature aging in mice based on altered stress-related behavioral response and immunosenescence.

The intensity of behavioral and neuroendocrine responses to stressful stimuli in rodent strains seems to be inversely related to their life span. We have previously shown that interindividual differences in members of outbred Swiss and inbred BALB/c mouse populations, both male and female, may be related to their behavior in a simple T-maze test. The animals that explore the maze slowly show impaired neuromuscular vigor and coordination, decreased locomotor activity, increased level of emotionality/anxiety, decreased levels of brain biogenic amines as well as immunosenescence and decreased life span, when compared to their control counterparts, which quickly explore the maze. These traits are similar to some of the alterations previously observed in aging animals and therefore we proposed that those 'slow mice' are biologically older than the fast animals and may be a model of prematurely aging mice (PAM). Although most of our work on this model has been performed on chronologically adult-mature animals, we have also shown that certain characteristics of PAM, such as increased anxiety and deficient immune response, are already present in chronologically young animals. Thus, it is tempting to hypothesize that chronic hyperreactivity to stress (trait anxiety) leading to immune dysfunction may have a causal relationship with impaired health and premature aging. In view of the link between oxidative stress and the aging process, the redox state of peritoneal leukocytes from PAM has been studied, showing an oxidative stress situation. In the present work we have determined the levels of a key antioxidant, reduced glutathione (GSH), and the oxidant malondialdehyde (MDA), a marker of lipid peroxidation, both in the spleen and brain of male and female PAM and non-PAM (NPAM). We found that GSH and MDA are decreased and increased, respectively, in PAM with respect to NPAM. Moreover, diet supplementation with antioxidants showed to be an effective strategy for protection against early immune and behavioral decline, altered redox state of leukocytes and premature mortality in PAM, which supports the validity of this model of premature aging as well as its link with oxidative stress.

Theories of ageing.

Ageing is a universal, intrinsic, progressive and deleterious process. Understanding it is of major interest to scientist, physicians as well as to the general population. Critical to this understanding is to formulate comprehensive theories of aging with high predictive and explanatory power. More than 300 theories have been postulated and are reviewed here. The free radical theory of ageing is one of the most prominent and well studied. It was further developed by one of us (JM) in what has become known as the mitochondrial theory of ageing. These theories provide new experimental approaches to further develop our understanding of the phenomenon of ageing.

Low concentrations of curcumin induce growth arrest and apoptosis in skin keratinocytes only in combination with UVA or visible light.

It is well known that curcumin, a dietary pigment from the plant Curcuma longa, inhibits cell proliferation and induces apoptosis in different cell lines at concentrations ranging from 10 to 150 microM (3.7-55 microg/ml). In this study, we show that curcumin at low concentrations (0.2-1 microg/ml) also has an antiproliferative effect when applied in combination with UVA or visible light. We demonstrate that such a treatment induces apoptosis in human skin keratinocytes represented by the increase of fragmented cell nuclei, release of cytochrome c from mitochondria, activation of caspases-9 and -8, and inhibition of NF-kappaB activity. Furthermore, inhibition of extracellular regulated kinases 1/2 and protein kinase B was found to ensure the proapoptotic effect. Additionally, the EGFR, an upstream regulator of both kinases, was inhibited indicating that apoptosis is induced by blocking survival- and proliferation-associated signal cascades at the receptor level. In summary, these findings suggest a new therapeutic concept for the treatment of hyperproliferative diseases by combining topical curcumin with UVA or visible light. In particular, the latter avoids the use of carcinogenic irradiation that is part of regular phototherapy.

Integración de teorías del envejecimiento (parte II) / Integration of theories of ageing (part II)

Numerosas hipótesis actuales proponen una relación directa entre el envejecimiento, los programas genéticos, la pérdida de telómeros que ocurre en cada división celular y la muerte celular apoptótica, y aunque todos estos procesos y mecanismos están probablemente implicados en las enfermedades asociadas con el envejecimiento, su papel en el envejecimiento normal de los organismos aún no se ha aclarado. Los estudios del proceso de envejecimiento «fisiológico» o «normal», en modelos de metazoo tan diversos como Drosophila y el ratón, apoyan el concepto de que una explicación lógica de este proceso (desde los puntos de vista de la biología celular, la genética, la bioenergética y la evolución) se podría obtener integrando varias teorías clásicas con conceptos más recientes. Así, el envejecimiento estaría ligado a la aparición en la biosfera de las células somáticas diferenciadas terminalmente, entre las que se encuentran la mayoría de las neuronas. Estas células fijas posmitóticas, por su alto consumo de oxígeno, consiguiente estrés oxidativo y falta de regeneración integral a través de la mitosis, experimentan un descenso en el número de mitocondrias funcionales. La pérdida de capacidad bioenergética resultante y el descenso del rendimiento fisiológico están implicados en el envejecimiento y muerte de los miembros de cada especie, cuyos genes, alojados en una sucesión de «somas desechables», sobreviven ilimitadamente en el hábitat normal de la especie gracias a la reproducción sexual

Many current hypotheses propose a direct association between aging, senescence-causing genetic programs, the telomere loss that accompanies each cell division and apoptotic cell death. Although all these processes and mechanisms are probably involved in age-related diseases, their precise role in normal aging has not been elucidated. The data reviewed on the process of normal aging in two models of metazoans as different as Drosophila and mouse support the concept that a logical explanation of this process (from the viewpoints of cell biology, genetics, bioenergetics and evolution) could be obtained by integrating several classical theories with more recent hypotheses. Thus, aging could be linked to the appearance in the biosphere of somatic cells that have gone through the process of terminal differentiation, such as most nerve cells. Because of their high oxygen consumption, resulting oxidative stress and lack of the rejuvenating action of mitosis, the number of functional mitochondria in these fixed postmitotic cells is reduced. The resulting loss of bioenergetic competence and physiological performance is involved in the senescence and death of the individual members of the metazoan species, whose genes, housed in a series of «disposable somas», have an unlimited survival in their normal habitat due to sexual reproduction

Menopause: a review on the role of oxygen stress and favorable effects of dietary antioxidants.

Menopause is often accompanied by hot flashes and degenerative processes such as arteriosclerosis and atrophic changes of the skin that suggest an acceleration of aging triggered by estrogen lack. Therefore, hormone replacement therapy (HRT) has been considered the most suitable treatment for the above symptoms and processes. However, because of the possible serious side effects of HRT (especially the increased risk of thrombo-embolic accidents and breast cancer) there is a growing demand for alternative treatments of the symptoms and pathological processes associated with menopause. In agreement with the above, we review research that supports the concept that oxygen stress contributes to menopause and that some of its physiopathological effects may be prevented and/or treated improving the antioxidant defense of menopausic and postmenopausic women. Accordingly, a selection of micronutrients may be useful as a dietary supplement for protection against the decline of physiological functions caused by age-related oxygen stress. Since aging is accompanied by a progressive oxidation of the physiological sulfur pool, we emphasize the role of the vitamins B that help to maintain the GSH/GSSG ratio in its normal reduced state. Nutritional supplements should also include the key antioxidant vitamins C and E, as well as beta-carotene and the mineral micronutrients found in the oxygen radical-detoxifying enzymes glutathione peroxidase and superoxide dismutase. Moreover, the reviewed data suport the concept that other antioxidants such as lipoic acid and the precursors of glutathione thioproline (TP) and l-2-oxothiazolidine-4-carboxylic acid (OTC), as well as the soy isoflavones and the "coantioxidants" of an hydroalcoholic extract of Curcuma longa may help to prevent antioxidant deficiency with resulting protection of mitochondria against premature oxidative damage with loss of ATP synthesis and especialized cellular functions. Therefore, the administration under medical advice of synergistic combinations of some of the above mentioned antioxidants in the diet as well as topically (for skin protection) may have favorable effects on the health and quality of life of women, especially of those who cannot be treated with HR, suffer high levels of oxygen stress, and do not consume a healthy diet that includes five daily rations of fresh fruit and vegetables.

Relation of behaviour and macrophage function to life span in a murine model of premature immunosenescence.

According to our previous work, mice of the same strain and age show striking inter-individual differences in behaviour when exposed to a T-maze test. Further, the animals exploring the maze slowly (slow mice) or staying at the starting point (freezing behaviour), which show high levels of emotionality/anxiety in other standard behavioural tests, have a less competent immune system (earlier immunosenescence) than those which explore it quickly (fast mice). The present longitudinal study on OF-1 Swiss female mice confirms and extends the above findings. Thus, the animals showing a lower performance in the T-test (slow mice) which is accompanied by a poor neuromuscular coordination in a tightrope test, have a shorter life span than the good performers (fast mice). Moreover, the slow mice have a less competent immune system as regards the following functions of peritoneal macrophages: adherence to substrate, chemotaxis, ingestion of particles and superoxide anion production. This suggests that, at the same chronological age and as regards their immune competence, the slow mice are biologically older than the fast mice. This agrees with current ideas on the close functional relationship between the nervous and the immune system in the physiological adaptation to stress, and supports the concept that an optimum level of performance of these two systems is needed to attain a long life span.

Mitocondrias, envejecimiento, músculo y ejercicio / Mitochondrias, ageing, muscle and exercise

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Can antioxidant diet supplementation protect against age-related mitochondrial damage?

Harman's free radical theory of aging and our electron-microscopic finding of an age-related mitochondrial degeneration in the somatic tissues of the insect Drosophila melanogaster as well as in the fixed postmitotic Leydig and Sertoli cells of the mouse testis led us to propose a mitochondrial theory of aging, according to which metazoan senescence may be linked to oxygen stress-injury to the genome and membranes of the mitochondria of somatic differentiated cells. These concepts attract a great deal of attention, since, according to recent work, the mitochondrial damage caused by reactive oxygen species (ROS) and concomitant decline in ATP synthesis seem to play a key role not only in aging, but also in the fundamental cellular process of apoptosis. Although diet supplementation with antioxidants has not been able to increase consistently the species-characteristic maximum life span, it results in significant extension of the mean life span of laboratory animals. Moreover, diets containing high levels of antioxidants such as vitamins C and E seem able to reduce the risk of suffering age-related immune dysfunctions and arteriosclerosis. Presently, the focus of age-related antioxidant research is on compounds, such as deprenyl, coenzyme Q10, alpha-lipoic acid, and the glutathione-precursors thioproline and N-acetylcysteine, which may be able to neutralize the ROS at their sites of production in the mitochondria. Diet supplementation with these antioxidants may protect the mitochondria against respiration-linked oxygen stress, with preservation of the genomic and structural integrity of these energy-producing organelles and concomitant increase in functional life span.