Genistein, a tool for geroscience.

Geroprotection is defined as protection from the adverse effects of aging. The need for geroprotection implies changes towards individually tailored interventions that preserve an individual's independence, physical function, and cognition. Genistein, a phytoestrogen obtained from soya, has been reported to have beneficial properties on age-related diseases such as neurodegenerative and cardiovascular diseases or cancer. Indeed, genistein is a multimodal agent: it acts as a cancer protective agent, promoting apoptosis and cell cycle arrest, and inhibiting angiogenesis and metastasis, but it also acts as an antioxidant, anti-inflammatory, and anti-amyloid-ß and autophagy promoter. Altogether, these properties make genistein a possible treatment for the specific aspects of age-related diseases such as hypertension, metabolic diseases, Alzheimer's disease, and osteoporosis.

Lifelong soya consumption in males does not increase lifespan but increases health span under a metabolic stress such as type 2 diabetes mellitus.

Soya consumption can decrease oxidative stress in animal models. Moreover, phytoestrogens such as genistein, present in soya, can mimic some of the beneficial effects of estrogens and are devoid of significant side effects, such as cancer. In this study, we have performed a controlled lifelong study with male OF1 mice that consumed either a soya-free diet or a soya-rich diet. We show that, although we found an increase in the expression and activity of antioxidant enzymes in soya-consuming mice, it did not increase lifespan. We reasoned that the soya diet could not increase lifespan in a very healthy population, but perhaps it could extend health span in stressed animals such as type 2 diabetic Goto Kakizaki (GK) rats. Indeed, this was the case: we found that male GK rats consuming a soya-rich diet developed the disease at a lower rate and, therefore, lived longer than soya-free diet-consuming rats.

Influence of different types of pulp treatment during isolation in the obtention of human dental pulp stem cells

BACKGROUND: Different methods have been used in order to isolate dental pulp stem cells. The aim of this study was to study the effect of different types of pulp treatment during isolation, under 3% O2 conditions, in the time needed and the efficacy for obtaining dental pulp stem cells. MATERIAL AND METHODS: One hundred and twenty dental pulps were used to isolate dental pulp stem cells treating the pulp tissue during isolation using 9 different methods, using digestive, disgregation, or mechanical agents, or combining them. The cells were positive for CD133, Oct4, Nestin, Stro-1, CD34 markers, and negative for the hematopoietic cell marker CD-45, thus confirming the presence of mesenchymal stem cells. The efficacy of dental pulp stem cells obtention and the minimum time needed to obtain such cells comparing the 9 different methods was analyzed. RESULTS: Dental pulp stem cells were obtained from 97 of the 120 pulps used in the study, i.e. 80.8% of the cases. They were obtained with all the methods used except with mechanical fragmentation of the pulp, where no enzymatic digestion was performed. The minimum time needed to isolate dental pulp stem cells was 8 hours, digesting with 2mg/ml EDTA for 10 minutes, 4mg/ml of type I collagenase, 4mg/ml of type II dispase for 40 minutes, 13ng/ ml of thermolysine for 40 minutes and sonicating the culture for one minute. CONCLUSIONS: Dental pulp stem cells were obtained in 97 cases from a series of 120 pulps. The time for obtaining dental pulp stem cells was reduced maximally, without compromising the obtention of the cells, by combining digestive, disgregation, and mechanical agents

Resveratrol: distribución, propiedades y perspectivas / Resveratrol: distribution, properties and perspectives

El resveratrol es un polifenol natural presente en numerosas plantas y frutos como cacahuetes, moras, arándanos y, sobre todo, en la uva y el vino tinto. Su síntesis está condicionada por la presencia de factores estresantes, tales como la contaminación fúngica o la radiación ultravioleta. En las plantas actúa como fitoalexina, es decir, posee la capacidad de inhibir el progreso de ciertas infecciones. La medicina antigua ha utilizado extractos de plantas que contienen resveratrol desde hace más de 2.000 años y hace más de 30 años que se aisló y se comenzaron a estudiar sus propiedades con métodos científicos. Sus propiedades in vitro han sido ampliamente estudiadas y contrastadas, entre ellas cabe destacar su actividad como anticancerígeno, antiagregante plaquetario, antiinflamatorio, antialérgico, etc. En cuanto a sus propiedades in vivo su actividad no está tan clara; existen numerosos estudios que encuentran beneficios sobre el sistema cardiovascular, enfermedades como la diabetes y sobre la longevidad; sin embargo, otros autores no encuentran una equivalencia de los estudios in vitro a in vivo. Esta discrepancia es debida a la biodisponibilidad que tiene el resveratrol. Tras un consumo oral se ha comprobado que la absorción es muy buena, pero las vías metabólicas dejan solo una pequeña fracción de resveratrol libre en sangre, por lo que la disponibilidad en los tejidos diana es muy baja y no se llegan a las concentraciones empleadas en los estudios in vitro. Así pues, aunque los estudios in vitro indican que se trata de una molécula biológicamente activa con propiedades saludables, los estudios realizados in vivo hasta el momento no pueden confirmar parte de estos resultados, lo cual puede atribuirse a su baja biodisponibilidad(AU)

Resveratrol is a natural polyphenol which can be found in many plants and fruits, such as peanuts, mulberries, blueberries and, above all, in grapes and red wine. Its synthesis is regulated by the presence of stressful factors, such as fungal contamination and ultra-violet radiation. In plants, it plays a role as a phytoalexin, showing a capacity to inhibit the development of certain infections. Plant extracts which contain resveratrol have been employed by traditional medicine for more than 2000 years. Resveratrol was first isolated, and its properties were initially studied with scientific methods, thirty years ago. Its in vitro properties have been extensively studied and demonstrated. It is worth highlighting its activity as an anti-cancer agent, platelet anti-aggregation agent, anti-inflammatory, antiallergenic, etc. The activity of its in vivo properties are not so clear. There are many studies that report benefits on the cardiovascular system, illnesses such as diabetes, and in longevity. However, other authors did not find any agreement between in vitro and in vivo studies. This discrepancy is due to the bioavailability of resveratrol. After an oral dose, it has been demonstrated that the absorption is very high, but the metabolic pathways leave just a little free resveratrol in blood, therefore the bioavailability in the target tissues is very low and the concentrations used in in vitro studies are not found in these tissues. Thus, resveratrol is a very active molecule for maintaining health, but due to the low bioavailability not all the in vitro effects can be translated to in vivo. This opens a new potential approach, seeking derivatives of resveratrol that can be measured in the desired tissues(AU)

[Resveratrol: distribution, properties and perspectives]. / Resveratrol: distribución, propiedades y perspectivas.

Resveratrol is a natural polyphenol which can be found in many plants and fruits, such as peanuts, mulberries, blueberries and, above all, in grapes and red wine. Its synthesis is regulated by the presence of stressful factors, such as fungal contamination and ultra-violet radiation. In plants, it plays a role as a phytoalexin, showing a capacity to inhibit the development of certain infections. Plant extracts which contain resveratrol have been employed by traditional medicine for more than 2000 years. Resveratrol was first isolated, and its properties were initially studied with scientific methods, thirty years ago. Its in vitro properties have been extensively studied and demonstrated. It is worth highlighting its activity as an anti-cancer agent, platelet anti-aggregation agent, anti-inflammatory, antiallergenic, etc. The activity of its in vivo properties are not so clear. There are many studies that report benefits on the cardiovascular system, illnesses such as diabetes, and in longevity. However, other authors did not find any agreement between in vitro and in vivo studies. This discrepancy is due to the bioavailability of resveratrol. After an oral dose, it has been demonstrated that the absorption is very high, but the metabolic pathways leave just a little free resveratrol in blood, therefore the bioavailability in the target tissues is very low and the concentrations used in in vitro studies are not found in these tissues. Thus, resveratrol is a very active molecule for maintaining health, but due to the low bioavailability not all the in vitro effects can be translated to in vivo. This opens a new potential approach, seeking derivatives of resveratrol that can be measured in the desired tissues.

Females live longer than males: role of oxidative stress.

One of the most significant achievements of the twentieth century is the increase in human lifespan. In any period studied, females live longer than males. We showed that mitochondrial oxidative stress is higher in males than females and that the higher levels of estrogens in females protect them against ageing, by up-regulating the expression of antioxidant, longevity-related genes. The chemical structure of estradiol confers antioxidant properties to the molecule. However, the low concentration of estrogens in females makes it unlikely that they exhibit significant antioxidant capacity in the organism. Therefore we studied the mechanisms enabling estradiol to be antioxidant at physiological levels. Our results show that physiological concentrations of estrogens activate estrogen receptors and the MAPK and NFKB pathway. Activation of NFkB by estrogens subsequently activates the expression of Mn-SOD and GPx. Moreover, we have demonstrated that genistein, the most abundant phytoestrogen in soya, reproduces the antioxidant effect of estradiol at nutritionally relevant concentrations by the same mechanism, both in healthy ageing and in Alzheimer's disease. We conclude that estrogens and phytoestrogens up-regulate expression of antioxidant enzymes via the estrogen receptor and MAPK activation, which in turn activate the NFkB signalling pathway, resulting in the up-regulation of the expression of longevity-related genes.

Women live longer than men: understanding molecular mechanisms offers opportunities to intervene by using estrogenic compounds.

Women live longer than men. Moreover, females live longer than males in some, but not all, experimental animals. The differences in longevity between genders are related to free radical production. Indeed, females produce less radicals only in animal species in which they live longer than males. This is because estrogens upregulate antioxidant longevity-related genes. These considerations have led us to postulate an extended concept of antioxidant in biology: an antioxidant is any nutritional, physiological, or pharmacological manipulation that increases the expression and activity of antioxidant genes or proteins. Phytoestrogens or other selective estrogen receptor modulators lower age-related diseases and prolong life span, at least in experimental animals. This provides rational bases to study their action in humans further.

Modulation of longevity-associated genes by estrogens or phytoestrogens.

Females live longer than males. We have shown that the higher levels of estrogens in females protect them against aging, by up-regulating the expression of antioxidant, longevity-related genes, such as that of selenium-dependent glutathione peroxidase (GPx) and Mn-superoxide dismutase (Mn-SOD). Both estradiol and genistein (the most abundant phytoestrogen in soybeans) share chemical properties which confer antioxidant features to these compounds. However, the low concentration of estrogens and phytoestrogens make it unlikely that they exhibit significant antioxidant capacity in the organism. Physiological concentrations of estrogens and nutritionally relevant concentrations of genistein activate the MAP kinase pathway. These, in turn, activate the nuclear factor kappa B (NF-kappa B) signaling pathway. Activation of NF-kappa B by estrogens subsequently activates the expression of Mn-SOD and GPx, but genistein is only capable of activating Mn-SOD expression. This could be due to the fact that genistein binds preferably to estrogen receptor beta. The antioxidant protection is reflected in the lower peroxide levels found in cells treated with estrogens or phytoestrogens when compared with controls. The challenge for the future is to find molecules that have the beneficial effects of estradiol, but without its feminizing effects. Phytoestrogens or phytoestrogen-related molecules may be good candidates to meet this challenge.

Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance.

BACKGROUND: Exercise practitioners often take vitamin C supplements because intense muscular contractile activity can result in oxidative stress, as indicated by altered muscle and blood glutathione concentrations and increases in protein, DNA, and lipid peroxidation. There is, however, considerable debate regarding the beneficial health effects of vitamin C supplementation. OBJECTIVE: This study was designed to study the effect of vitamin C on training efficiency in rats and in humans. DESIGN: The human study was double-blind and randomized. Fourteen men (27-36 y old) were trained for 8 wk. Five of the men were supplemented daily with an oral dose of 1 g vitamin C. In the animal study, 24 male Wistar rats were exercised under 2 different protocols for 3 and 6 wk. Twelve of the rats were treated with a daily dose of vitamin C (0.24 mg/cm2 body surface area). RESULTS: The administration of vitamin C significantly (P=0.014) hampered endurance capacity. The adverse effects of vitamin C may result from its capacity to reduce the exercise-induced expression of key transcription factors involved in mitochondrial biogenesis. These factors are peroxisome proliferator-activated receptor co-activator 1, nuclear respiratory factor 1, and mitochondrial transcription factor A. Vitamin C also prevented the exercise-induced expression of cytochrome C (a marker of mitochondrial content) and of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. CONCLUSION: Vitamin C supplementation decreases training efficiency because it prevents some cellular adaptations to exercise.

Oestradiol or genistein rescues neurons from amyloid beta-induced cell death by inhibiting activation of p38.

Oestrogenic compounds have been postulated as neuroprotective agents. This prompted us to investigate their mechanism action in neurons in primary culture. Cells were pretreated with physiological concentrations of 17-beta estradiol (0.2 nm) or with nutritionally relevant concentrations of genistein (0.5 microm), and 48 h later treated with 5 microm of amyloid beta (Abeta) for 24 h. We found that Abeta increased oxidative stress, measured as peroxide levels or oxidized glutathione/reduced glutathione ratio, which in turn, caused phosphorylation of p38 MAP kinase. Amyloid beta subsequently induced neuronal death. Inhibiting the MAP kinase pathway prevented cell death, confirming the role of p38 in the toxic effect of Abeta. All these effects were prevented when cells were pretreated for 48 h with oestradiol or genistein. Therefore, oestrogenic compounds rescue neurons from Abeta-induced cell death by preventing oxidative stress, which in turn inhibits the activation of p38, protecting neurons from cell death. Because hormone replacement therapy with oestradiol could cause serious setbacks, the potential therapeutic effect of phyto-oestrogens for the prevention of Abeta-associated neurodegenerative disorders should be more carefully studied in clinical research.

Fostering antioxidant defences: up-regulation of antioxidant genes or antioxidant supplementation?

Vitamins have traditionally been considered as food components that are required in the normal diet to prevent deficiencies. However, a newer concept of the function of vitamins in nutrition has taken them beyond simply prevention of deficiency symptoms. This concept considers that many vitamins, when taken in relatively large doses, have important functions beyond preventing deficiencies. Linus Pauling was instrumental in putting forward this concept, particularly for vitamin C. Thus, relatively high intakes of vitamins, and in particular vitamins C and E which are antioxidants, are considered to be healthy for the human population. This may be true in some special situations such as, for instance, the prevention of Alzheimer's disease progression. However, recent epidemiological evidence has not supported the claim that antioxidant vitamins increase well-being and prolong life span. In fact, vitamin supplementation may be even detrimental and reduce life span. A new concept that we would like to put forward is that nutrients up-regulate the endogenous antioxidant defences. This is particularly true in the case of phytoestrogens for example, which bind to oestrogen receptors and eventually up-regulate the expression of antioxidant genes. In this review we discuss the pros and cons of antioxidant vitamin supplementation and also the possibility that the ingestion of some nutrients may be very effective in increasing antioxidant defences by up-regulating the activity of antioxidant enzymes which are normally present in the cell.

Part of the series: from dietary antioxidants to regulators in cellular signalling and gene expression. Role of reactive oxygen species and (phyto)oestrogens in the modulation of adaptive response to stress.

There is increasing evidence that reactive oxygen species (ROS) are not only toxic but play an important role in cellular signalling and in the regulation of gene expression. We, here, discuss two examples of improved adaptive response to an altered cellular redox state. First, differences in longevity between males and females may be explained by a higher expression of antioxidant enzymes in females resulting in a lower yield of mitochondrial ROS. Oestrogens are made responsible for these phenomena. Oestradiol induces glutathione peroxidase-1 and MnSOD by processes requiring the cell surface oestrogen receptor (ER) and the activation of pathways usually involved in oxidative stress response. Second, oxygen radicals produced during moderate exercise as performed during training up-regulate the expression of antioxidant enzymes in muscle cells. An increased level of these enzymes might prevent oxidative damage during exhaustive exercise and should, therefore, not be prevented by antioxidants. The relevance of these findings is discussed in the context with observations made in transgenic animals overexpressing MnSOD or catalase.

Dietary soy isoflavone induced increases in antioxidant and eNOS gene expression lead to improved endothelial function and reduced blood pressure in vivo.

Epidemiological evidence suggests that populations consuming large amounts of soy protein have a reduced incidence of coronary heart disease (1-5). The cardiovascular risks associated with conventional hormone replacement therapy in postmenopausal women (5-7) have precipitated a search for alternative estrogen receptor modulators. Here we report that long-term feeding of rats with a soy protein-rich (SP) diet during gestation and adult life results in decreased oxidative stress, improved endothelial function, and reduced blood pressure in vivo measured by radiotelemetry in aged male offspring. Improved vascular reactivity in animals fed an SP diet was paralleled by increased mitochondrial glutathione and mRNA levels for endothelial nitric oxide synthase (eNOS) and the antioxidant enzymes manganese superoxide dismutase and cytochrome c oxidase. Reduced eNOS and antioxidant gene expression, impaired endothelial function, and elevated blood pressure in animals fed a soy-deficient diet was reversed after refeeding them an SP diet for 6 months. Our findings suggest that an SP diet increases eNOS and antioxidant gene expression in the vasculature and other tissues, resulting in reduced oxidative stress and increased NO bioavailability. The improvement in endothelial function, increased gene expression, and reduced blood pressure by soy isoflavones have implications for alternative therapy for postmenopausal women and patients at risk of coronary heart disease.

Why females live longer than males? Importance of the upregulation of longevity-associated genes by oestrogenic compounds.

Females live longer than males in many mammalian species, including humans. Mitochondria from females produce approximately half the amount of H(2)O(2) than males. We have found that females behave as double transgenics overexpressing both superoxide dismutase and glutathione peroxidase. This is due to oestrogens that act by binding to the estrogen receptors and subsequently activating the mitogen activated protein (MAP) kinase and nuclear factor kappa B (NF-kappaB) signalling pathways. Phytoestrogens mimic the protective effect of oestradiol using the same signalling pathway. The critical importance of upregulating antioxidant genes, by hormonal and dietary manipulations, in order to increase longevity is discussed.

Ginkgo biloba extract EGb 761 protects against mitochondrial aging in the brain and in the liver.

According to the free radical theory of aging, oxygen-derived free radicals causes the age-associated impairment at the cellular and tissue levels. The mitochondrial theory of aging points to mitochondria, and specially mitochondrial DNA, as the major targets of free radical attack upon aging. Thus, oxidative damage to mtDNA accumulate with age in human and rodent tissues and also is inversely related to maximum life span of mammals. Mitochondrial deficits, such as a decrease in mitochondrial membrane potential, occur upon aging due to oxidative damage. The age-related mitochondrial oxidative stress may be prevented by late onset administration of certain antioxidants, such as Ginkgo biloba extract EGb 761. These antioxidants may also delay the physiological impairment associated with aging.