Nutrition and ageing

The underlying mechanism of nuclear and mitochondrial DNA damages in triggering cancer incidences: Insights into proteomic and genomic sciences

The attempt of this review article is to determine the impact of nuclear and mitochondrial damages on the propagation of cancer incidences. This review has advanced our understanding to altered genes and their relevant cancerous proteins. The progressive raising effects of free reactive oxygen species ROS and toxicogenic compounds contributed to significant mutation in nuclear and mitochondrial DNA where the incidence of gastric cancer is found to be linked with down regulation of some relevant genes and mutation in some important cellular proteins such as AMP-18 and CA-11. Thereby, the resulting changes in gene mutations induced the apparition of newly polymorphisms eventually leading to unusual cellular expression to mutant proteins. Reduction of these apoptotic growth factors and nuclear damages is increasingly accepted by cell reactivation effect, enhanced cellular signaling and DNA repairs. Acetylation, glycation, pegylation and phosphorylation are among the molecular techniques used in DNA repair for rectifying mutation incidences. In addition, the molecular labeling based fluorescent materials are currently used along with the bioconjugating of signal molecules in targeting disease translocation site, particularly cancers and tumors. These strategies would help in determining relevant compounds capable in overcoming problems of down regulating genes responsible for repair mechanisms. These issues of course need interplay of both proteomic and genomic studies often in combination of molecular engineering to cible the exact expressed gene relevant to these cancerous proteins.

Dietary Inflammatory Index and Associations with Sarcopenia Symptomology in Community-Dwelling Older Adults

Low-grade systemic inflammation is a key driver of muscle degeneration in older adults, and diets with pro-inflammatory properties may further contribute to loss of muscle mass, strength and function. Therefore, this research aimed to explore the associations between the inflammatory potential of the diet and measures of sarcopenia symptomology in community-dwelling older adults. Upper (handgrip strength, HGS) and lower extremity (sit-to-stand) muscle strength, physical performance (timed-up-and-go, TUG) and appendicular skeletal muscle mass (ASM) was assessed according to the European Working Group on Sarcopenia in Older People version 2 (EWGSOP2) criteria. Multiple 24-hr dietary recalls were used to calculate the Dietary Inflammatory Index (DII), which was then used to group participants into anti- and pro-inflammatory dietary groups. Multiple linear regression investigated associations between DII, muscle strength, physical performance, and muscle quantity adjusted for age, gender, comorbidities, waist circumference and physical activity. Adults 65-85 years (n = 110, 72.1 ± 4.7 years, 76.4% female) were recruited. One participant was identified with sarcopenia, 35.2% were pre-frail, or frail. More participants with a pro-inflammatory DII score had low muscle quantity than those with anti-inflammatory DII (3.4% vs. 6.4%, x² = 4.537, p = 0.043) and DII was negatively associated with HGS (β = -0.157, p = 0.016) and ASM (β = -0.176, p = 0.002) which remained significant after adjusting for covariates. In this population, DII was associated with less favorable muscle strength, physical performance, and muscle quantity.

Supplementation with Triptolide Increases Resistance to Environmental Stressors and Lifespan in C. elegans

Triptolide is a major active compound found in Tripterygium wilfordii., also known as Thunder God Vine. Triptolide has been shown to have anti-inflammatory and anticancer activities. In this study, we examined the effect of dietary supplementation with triptolide on response to environmental stressors and lifespan in vivo using Caenorhabditis elegans as a model system. Treatment with 50 mg/L of triptolide in the growth media increased resistance to oxidative stress and reduced the generation of intracellular reactive oxygen species. We also observed a lifespan-extending activity for triptolide. Both mean and maximum lifespans were significantly increased by supplementation with triptolide. Response to other environmental stressors was modulated by triptolide. The survival after heat shock or UV irradiation was markedly increased in worms treated with triptolide. Unlike many lifespan-extending genetic or nutritional interventions, the longevity phenotype conferred by triptolide did not have the trade-off of a reduction in fertility or a delay in the gravid period. The expressions of hsp-16.2 and sod-3, known to positively correlate with a long lifespan, were significantly upregulated by supplementation with triptolide. These findings suggest that triptolide can exhibit antistress and lifespan-extending effects in vivo, possibly through its antioxidant activity and support the free radical theory of aging, which emphasizes the causative role of oxidative stress in aging.

Tenebrio molitor Extracts Modulate the Response to Environmental Stressors and Extend Lifespan in Caenorhabditis elegans

Tenebrio molitor are large insects and their larvae are consumed as food in many countries. The nutritional composition of T. molitor has been studied and contains high amounts of proteins, unsaturated fatty acids, and valuable minerals. However, the bioactivity of T. molitor has not been fully understood. We examined the effects of T. molitor extracts on resistance to oxidative stress and organism's lifespan using Caenorhabditis elegans as a model system. The response to heat shock and ultraviolet (UV) irradiation was monitored in vivo. The extracts from T. molitor showed significant effects on resistance to oxidative stress and UV irradiation and extend both mean and maximum lifespan of C. elegans. The number of progeny produced significantly increased in animals supplemented with T. molitor extracts. In addition, the expression of hsp-16.2 and sod-3 was markedly upregulated by supplementation with T. molitor extracts. These findings suggest that T. molitor extracts can increase response to stressors and extend lifespan by the induction of longevity assurance genes in C. elegans.

The effects of combined free radical scavenger and sildenafil therapy on age-associated erectile dysfunction: An animal model

Introduction:

Aging results in erectile dysfunction that is partially attributed to decreased nitric oxide (NO) and increased free radical generation. Vitamin E enhances endothelial cell function and acts as a free radical scavenger; however, its benefits on erectile function in the elderly are unknown.

Aims:

The aim of the following study is to determine if Vitamin E alone, or in combination with the phosphodiesterase 5 inhibitor sildenafil, may improve erectile function and the NO signaling in a cohort of aged (13-15 month old) rats.

Materials and Methods:

Male Sprague-Dawley rats (n = 28) were divided based upon age into young (4-5 months old, n = 7) and aged (13-15 months old, n = 21) cohorts. Aged rats were treated with Vitamin E, sildenafil or a combination of both. Penile cavernosal and dorsal nerve tissues were evaluated for neuronal nitric oxide synthase (nNOS) and caveolin-1 expression. Erectile function was assessed through intra-cavernous pressure (ICP) recordings.

Results:

nNOS and cavoelin-1 were significantly decreased in aged rats compared with young controls. In aged rats, both Vitamin E and sildenafil partially recovered nNOS expression but when combined, a synergistic elevation in nNOS was observed. The significant decreases in ICP recorded in aged rats were improved with sildenafil; however, Vitamin E did not yield any additional improvements in ICP.

Conclusions:

Diminished levels of nNOS and caveolin-1 are found in aged rats. When combined with sildenafil, Vitamin E synergistically increased nNOS expression. Since biochemical gains were not realized physiologically, other contributing factors likely exist.

Flow cytometric analysis of age-related changes in intestine intraepithelial lymphocyte subsets and their functional preservation after feeding mice on spirulina

We investigated age-related changes in intestinal intraepithelial lymphocyte (IEL) subsets in mice by flow cytometric analysis and their functional preservation as affected by feeding Spirulina, a cyanobacterium that is known to possess various therapeutic effects, including immune modulation activity. The number of cells possessing the leukocyte-common antigen CD45(+) cells in mice (43 weeks old) of the aged group, used as a representative marker for IELs, was significantly lower than that of adult mice (5 weeks old). Either the proportion or the number of CD45(+)CD8(+) cells of the aged mice was significantly lower than that of adult mice, corresponding to previous reports. Proportions and numbers of CD4(+)CD8(+) cells in aged mice, on the other hand, were higher than those in adult mice. Increased or decreased levels of the cell surface antigens observed in the aged mice tended to be restored in aged mice fed Spirulina (aged-SP group), which ingested a hot water extract of Spirulina (SpHW). In fact, the proportions of CD45(+)CD8(+) cells and CD45(+)TCRgammadelta(+) cells in the aged-SP group significantly increased in comparison to the control aged group, which ingested ordinary chow and water ad libitum. These results suggest that ingestion of SpHW in the aged-SP group may contribute to the functional preservation of the intestinal epithelium as a first line of mucosal barrier against infectious agents through retaining the number of certain IELs. Changes in the number of other IEL subsets and blood cells are also discussed.

alpha- and gamma-Tocopherol prevent age-related transcriptional alterations in the heart and brain of mice

We used high-density oligonucleotide arrays to measure transcriptional alterations in the heart and brain (neocortex) of 30-mo-old B6C3F(1) mice supplemented with alpha-tocopherol (alphaT) and gamma-tocopherol (gammaT) since middle age (15 mo). Gene expression profiles were obtained from 5- and 30-mo-old control mice and 30-mo-old mice supplemented with alphaT (1 g/kg) or a mixture of alphaT and gammaT (500 mg/kg of each tocopherol) from middle age (15 mo). In the heart, both tocopherol-supplemented diets were effective in inhibiting the expression of genes previously associated with cardiomyocyte hypertrophy and increased innate immunity. In the brain, induction of genes encoding ribosomal proteins and proteins involved in ATP biosynthesis was observed with aging and was markedly prevented by the mixture of alphaT and gammaT supplementation but not by alphaT alone. These results demonstrate that middle age-onset dietary supplementation with alphaT and gammaT can partially prevent age-associated transcriptional changes and that these effects are tissue and tocopherol specific.

Control of energy balance in relation to energy intake and energy expenditure in animals and man: an ecological perspective

In this paper, we consider the control of energy balance in animals and man. We argue that patterns of mammalian feeding have evolved to control energy balance in uncertain environments. It is, therefore, expected that, under sedentary conditions in which the diet is rich in nutrients and abundantly available, animals and man will overeat. This suggests that no physiological defects are needed to induce overweight and ultimately obesity in man. Several considerations arise from these observations. The time period over which energy balance is controlled is far longer than allowed by most experiments. Physiological models of energy balance control often treat excess energy intake as a defect of regulation; ecological models view the same behaviour as part of normal energy balance control in environments where resources are uncertain. We apply these considerations to common patterns of human and animal feeding. We believe that the ecological perspective gives a more accurate explanation for the functionality of excess fat and the need to defend nutrient balance and avoid gross imbalances, as well as explaining hyperphagia in the face of plenty. By emphasising the common features of energy balance control in different mammalian species, the importance of changes in behaviour to accommodate changes in the environment becomes apparent. This also opens up possibilities for the control of body weight and the treatment of obesity in man.

Melatonin reduces oxidative stress in erythrocytes and plasma of senescence-accelerated mice

It has been suggested that oxidative stress is a feature of aging. The goal of the present study was to assess the oxidant effects related to aging and the protective role of exogenous melatonin in senescence-accelerated mice (SAMP8). Two groups of SAMP8 mice (males and females) were compared with their respective control groups of SAMR1 mice (senescence-resistant inbred strain) to determine their oxidative status without melatonin treatment. Four other groups of the same characteristics were treated with melatonin (10 mg/kg/day) in their drinking water. The melatonin concentration in the feeding bottles was titrated according to water consumption and body weight (i.e. 0.06 mg/mL for 30 g of body weight and 5 mL/day of water consumption). The treatment began when animals were 1-month old and continued for 9 months. When mice were 10-month old, they were anesthetized and blood was obtained. Plasma and erythrocytes were processed to examine oxidative stress markers: reduced glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST), thiobarbituric acid reactive substances (TBARS), and hemolysis. The results showed greater oxidative stress in SAMP8 than in SAMR1, largely because of a decrease in GSH levels and to an increase in GSSG and TBARS with the subsequent induction of the antioxidant enzymes GPX and GR. Melatonin, as an antioxidant molecule, improved the glutathione-related parameters, prevented the induction of GPX in senescent groups, and promoted a decrease in SOD and TBARS in almost all the groups.

Oxidative stress in leukocytes from young prematurely aging mice is reversed by supplementation with biscuits rich in antioxidants

Aging is associated with a progressive dysregulation of immune responses as a result of increased oxidative stress. Therefore, we have assessed the oxidative stress status of peritoneal leukocytes from young prematurely aging mice (PAM) as compared with non-prematurely aging mice (NPAM), as well as the effects on this oxidative stress of a dietary supplementation with biscuits rich in antioxidants (vitamin C, vitamin E, beta-carotenes, zinc and selenium). We found that, in the peritoneal leukocytes, the levels of several parameters of oxidation such as extracellular superoxide anion (O(2)(-)), Prostaglandin E(2) (PGE(2)), nitric oxide, oxidized glutathione (GSSG) and lipid peroxidation (malondialdehyde, MDA) were higher in PAM as compared with NPAM, whereas the antioxidant defences such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities, as well as reduced glutathione (GSH) levels, were decreased. Consequently, young PAM showed an oxidative stress in their leukocytes, which is characteristic of mice of an older chronological age. Antioxidant diet supplementation was able to restore redox homeostasis, increasing the antioxidant and decreasing the oxidant levels. Accordingly, supplementation with adequate levels of antioxidants, from an early age, could be useful to preserve health, especially in prematurely aging populations.

alpha-Tocopherol and selenium facilitate recovery from lipopolysaccharide-induced sickness in aged mice

The elderly suffer a decline in immune function that increases their vulnerability to infections. Because antioxidants improve some age-related deficits in immune and cognitive function, our goal was to determine whether dietary alpha-tocopherol (alpha-T) and selenium inhibit LPS-induced sickness behavior in aged mice. Male BALB/c mice were fed modified AIN93-M diets that were low, adequate, or high in both alpha-T (10, 75, or 500 mg/kg) and selenium (0.05, 0.15, or 2 mg/kg) from 18 to 21 mo of age. Sickness was quantified by measuring time in social exploration of a novel juvenile conspecific. The lipopolysaccharide treatment reduced social exploration by 74% at 2 h, regardless of diet. By 4 h, aged mice fed the low diet were 88% less social, whereas mice fed the adequate and high diets displayed only approximately 40% reductions due to LPS treatment. Mice fed the low diet had greater LPS-induced weight loss than mice fed the high diet. Plasma alpha-T concentration and glutathione peroxidase (GPX) activity increased with each increment in alpha-T and selenium 24 h post-LPS treatment. Brain alpha-T concentration and GPX activity were lower in mice fed the low diet than in those fed the adequate or high diet. Regardless of diet, interleukin (IL)-6, IL-1beta, and tumor necrosis factor (TNF)alpha mRNA levels were elevated by LPS approximately 3-fold in cortex, cerebellum, striatum, and hippocampus. Thus, antioxidants inhibit sickness behavior independently of IL-6, IL-1beta, and TNFalpha mRNA levels 2 h post-LPS in the brain regions analyzed. Taken together, these findings suggest that adequate intake of dietary alpha-T and selenium may help promote recovery from gram-negative bacterial infection in the aged.

Mitochondrial dysfunctions during aging: vitamin E deficiency or caloric restriction--two different ways of modulating stress

Caloric restriction (CR), which has been demonstrated to offset the age-associated accrual of oxidative injury, involves a reduction in calory intake while maintaining adequate nutrition, preserves the activities of antioxidant enzymes in postmitotic tissues, maintains organ function, opposes the development of spontaneous diseases, and prolongs maximum life span in laboratory rodents. It has been proposed that reductions in Reactive Oxygen Species (ROS) production and cellular oxidative injury are central to the positive effects of CR. In the present investigation we studied the effect of CR and of a vitamin E deprived diet on mitochondrial structure and features in the liver of rats during aging, in order to ascertain the extent of modifications induced by these experimental conditions. CR rats displayed structural and functional mitochondrial properties (fatty acid pattern, respiratory chain activities, antioxidant levels, and hydroperoxide contents) similar to those of younger rats whilst vitamin E deficient rats appeared older than their own age. The mitochondria of the former, together with those of young rats, possessed the lowest Coenzyme Q9, hydroperoxide, and cytochrome contents as well as a suitable fatty acid membrane composition. Our study confirms that CR is a valuable tool in limiting aging-related free-radical damage also at mitochondrial liver level.

Can coenzyme Q10 improve vascular function and blood pressure? Potential for effective therapeutic reduction in vascular oxidative stress

Coenzyme Q10 (CoQ) is an endogenously synthesised compound that acts as an electron carrier in the mitochondrial electron transport chain. The presence of adequate tissue concentrations of CoQ may be important in limiting oxidative and nitrosative damage in vivo. Oxidative and nitrosative stress are likely to be elevated in conditions such as diabetes and hypertension. In these conditions elevated oxidative and nitrosative stress within the arterial wall may contribute to increased blood pressure and vascular dysfunction. The major focus of this review is the potential of CoQ to improve vascular function and lower blood pressure. Although there is substantial indirect support for the putative mechanism of effect of CoQ on the vascular system, to date there is little direct support for an effect of CoQ on in vivo markers of oxidative or nitrosative stress. The limited data available from studies in animal models and from human intervention studies are generally consistent with a benefit of CoQ on vascular function and blood pressure. The observed effects of CoQ on these endpoints are potentially important therapeutically. However, before any firm clinical recommendations can be made about CoQ supplementation, further intervention studies in humans are needed to investigate the effects of CoQ on vascular function, blood pressure and cardiovascular outcomes. The particularly relevant groups of patients for these studies are those with insulin resistance, type 2 diabetes, hypertension and the metabolic syndrome.

The evolution of the control of food intake

The ultimate goal of an organism is to maximise its inclusive fitness, and an important sub-goal must be the optimisation of the lifetime pattern of food intake, in order to meet the nutrient demands of survival, growth and reproduction. The conventional assumption that fitness is maximised by maximising daily food intake, subject to physical and physiological constraints, has been challenged recently. Instead, it can be argued that fitness is maximised by balancing benefits and costs over the organism's lifetime. The fitness benefits of food intake are a function of its contribution to survival, growth (including necessary body reserves) and reproduction. Against these benefits must be set costs. These costs include not only extrinsic foraging costs and risks, such as those due to predation, but also intrinsic costs associated with food intake, such as obesity and oxidative metabolism that may reduce vitality and lifespan. We argue that the aggregate of benefits and costs form the fitness function of food intake and present examples of such an approach to predicting optimal food intake.