Nutritional implications of the free-radical theory of aging

Effects of the Phytochemical Combination PB123 on Nrf2 Activation, Gene Expression, and the Cholesterol Pathway in HepG2 Cells

There has been a long history of human usage of the biologically-active phytochemicals in Salvia rosmarinus, Zingiber officinale, and Sophora japonica for health purposes, and we recently reported on a combination of those plant materials as the PB123 dietary supplement. In the present work we extended those studies to evaluate activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor and differential gene expression in cultured HepG2 (hepatocellular carcinoma) cells treated with PB123. We determined transcriptome changes using mRNA-seq methods, and analyzed the affected pathways using Ingenuity Pathway Analysis and BioJupies, indicating that primary effects included increasing the Nrf2 pathway and decreasing the cholesterol biosynthesis pathway. Pretreatment of cultured HepG2 cells with PB123 upregulated Nrf2-dependent cytoprotective genes and increased cellular defenses against cumene hydroperoxide-induced oxidative stress. In contrast, pretreatment of cultured HepG2 cells with PB123 downregulated cholesterol biosynthesis genes and decreased cellular cholesterol levels. These findings support the possible beneficial effects of PB123 as a healthspan-promoting dietary supplement.

The ocular surface immune system through the eyes of aging

Since the last century, advances in healthcare, housing, and education have led to an increase in life expectancy. Longevity is accompanied by a higher prevalence of age-related diseases, such as cancer, autoimmunity, diabetes, and infection, and part of this increase in disease incidence relates to the significant changes that aging brings about in the immune system. The eye is not spared by aging either, presenting with age-related disorders of its own, and interestingly, many of these diseases have immune pathophysiology. Being delicate organs that must be exposed to the environment in order to capture light, the eyes are endowed with a mucosal environment that protects them, the so-called ocular surface. As in other mucosal sites, immune responses at the ocular surface need to be swift and potent to eliminate threats but are at the same time tightly controlled to prevent excessive inflammation and bystander damage. This review will detail how aging affects the mucosal immune response of the ocular surface as a whole and how this process relates to the higher incidence of ocular surface disease in the elderly.

Amyotrophic Lateral Sclerosis Genes in Drosophila melanogaster

Amyotrophic lateral sclerosis (ALS) is a devastating adult-onset neurodegenerative disease characterized by the progressive degeneration of upper and lower motoneurons. Most ALS cases are sporadic but approximately 10% of ALS cases are due to inherited mutations in identified genes. ALS-causing mutations were identified in over 30 genes with superoxide dismutase-1 (SOD1), chromosome 9 open reading frame 72 (C9orf72), fused in sarcoma (FUS), and TAR DNA-binding protein (TARDBP, encoding TDP-43) being the most frequent. In the last few decades, Drosophila melanogaster emerged as a versatile model for studying neurodegenerative diseases, including ALS. In this review, we describe the different Drosophila ALS models that have been successfully used to decipher the cellular and molecular pathways associated with SOD1, C9orf72, FUS, and TDP-43. The study of the known fruit fly orthologs of these ALS-related genes yielded significant insights into cellular mechanisms and physiological functions. Moreover, genetic screening in tissue-specific gain-of-function mutants that mimic ALS-associated phenotypes identified disease-modifying genes. Here, we propose a comprehensive review on the Drosophila research focused on four ALS-linked genes that has revealed novel pathogenic mechanisms and identified potential therapeutic targets for future therapy.

Modulation of Oxidative Stress and Inflammation in the Aged Lacrimal Gland

Inflammation and oxidative stress accompany aging. This study investigated the interplay between oxidative stress and inflammation in the lacrimal gland. C57BL/6 mice were used at 2 to 3, 12, and 24 months of age. Nuclear factor erythroid derived-2-related factor 2 (Nrf2)^-/- and corresponding wild-type mice were used at 2 to 3 and 12 to 13 months of age. A separate group of 15.5 to 17 months of age C57BL/6 mice received a diet containing an Nrf2 inducer (Oltipraz) for 8 weeks. Aged C57BL/6 lacrimal glands showed significantly greater lymphocytic infiltration, higher levels of MHC II, IFN-γ, IL-1β, TNF-α, and cathepsin S (Ctss) mRNA transcripts, and greater nitrotyrosine and 4-hydroxynonenal protein. Young Nrf2^-/- mice showed an increase in IL-1β, IFN-γ, MHC II, and Ctss mRNA transcripts compared with young wild-type mice and greater age-related changes at 12 to 13 months of age. Oltipraz diet significantly decreased nitrotyrosine and 4-hydroxynonenal and decreased the expression of IL-1β and TNF-α mRNA transcripts, while decreasing the frequency of CD45⁺CD4⁺ cells in lacrimal glands and significantly increasing conjunctival goblet cell density compared with a standard diet. The findings provide novel insight into the development of chronic, low-grade inflammation and oxidative stress in age-related dry eye. New therapies targeting oxidative stress pathways will be valuable in treating age-related dry eye.

Phytochemical and Biological Investigation of Helianthemum nummularium, a High-Altitude Growing Alpine Plant Overrepresented in Ungulates Diets

Helianthemum nummularium is a European shrub growing at high altitude where it copes with a high level of stress. It was found to be overexpressed in ungulates diets compared to more abundant surrounding plants. These elements combined with the fact that H. nummularium from the Alps has never been investigated prompted us to study the phytochemical composition of its aerial parts. The analysis of the polar extract allowed for the isolation of eight compounds: p-hydroxybenzoic acid, tiliroside, kaempferol, astragalin, quercetin, plantainoside B, quercetin-3-O-glucoside, and quercetin-3-O-glucuronide. We investigated the effect of the polar extract and isolated compounds on nuclear factor erythroid 2-related factor 2 transcription factor, which regulates the expression of a wide variety of cytoprotective genes. We found that the ethanolic extract activates the expression of nuclear factor erythroid 2-related factor 2 in a dose-dependent manner, whereas the pure compounds were much less active. The activation of the nuclear factor erythroid 2-related factor 2 pathway by the plant extract could pave the way for studies to promote healthy aging through protection of cells against oxidative stress. Moreover, the isolated compounds could be investigated alone or in combination in the perspective of making the link between the ungulate's preference for this plant and possible use of it for self-medication.

Phytochemical Combination PB125 Activates the Nrf2 Pathway and Induces Cellular Protection against Oxidative Injury

Bioactive phytochemicals in Rosmarinus officinalis, Withania somnifera, and Sophora japonica have a long history of human use to promote health. In this study we examined the cellular effects of a combination of extracts from these plant sources based on specified levels of their carnosol/carnosic acid, withaferin A, and luteolin levels, respectively. Individually, these bioactive compounds have previously been shown to activate the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor, which binds to the antioxidant response element (ARE) and regulates the expression of a wide variety of cytoprotective genes. We found that combinations of these three plant extracts act synergistically to activate the Nrf2 pathway, and we identified an optimized combination of the three agents which we named PB125 for use as a dietary supplement. Using microarray, quantitative reverse transcription-PCR, and RNA-seq technologies, we examined the gene expression induced by PB125 in HepG2 (hepatocellular carcinoma) cells, including canonical Nrf2-regulated genes, noncanonical Nrf2-regulated genes, and genes which appear to be regulated by non-Nrf2 mechanisms. Ingenuity Pathway Analysis identified Nrf2 as the primary pathway for gene expression changes by PB125. Pretreatment with PB125 protected cultured HepG2 cells against an oxidative stress challenge caused by cumene hydroperoxide exposure, by both cell viability and cell injury measurements. In summary, PB125 is a phytochemical dietary supplement comprised of extracts of three ingredients, Rosmarinus officinalis, Withania somnifera, and Sophora japonica, with specified levels of carnosol/carnosic acid, withaferin A, and luteolin, respectively. Each ingredient contributes to the activation of the Nrf2 pathway in unique ways, which leads to upregulation of cytoprotective genes and protection of cells against oxidative stress and supports the use of PB125 as a dietary supplement to promote healthy aging.

Chronic systemic D-galactose exposure induces memory loss, neurodegeneration, and oxidative damage in mice: protective effects of R-alpha-lipoic acid

Chronic systemic exposure of mice, rats, and Drosophila to D-galactose causes the acceleration of senescence and has been used as an aging model. The underlying mechanism is yet unclear. To investigate the mechanisms of neurodegeneration in this model, we studied cognitive function, hippocampal neuronal apoptosis and neurogenesis, and peripheral oxidative stress biomarkers, and also the protective effects of the antioxidant R-alpha-lipoic acid. Chronic systemic exposure of D-galactose (100 mg/kg, s.c., 7 weeks) to mice induced a spatial memory deficit, an increase in cell karyopyknosis, apoptosis and caspase-3 protein levels in hippocampal neurons, a decrease in the number of new neurons in the subgranular zone in the dentate gyrus, a reduction of migration of neural progenitor cells, and an increase in death of newly formed neurons in granular cell layer. The D-galactose exposure also induced an increase in peripheral oxidative stress, including an increase in malondialdehyde, a decrease in total anti-oxidative capabilities (T-AOC), total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-Px) activities. A concomitant treatment with lipoic acid ameliorated cognitive dysfunction and neurodegeneration in the hippocampus, and also reduced peripheral oxidative damage by decreasing malondialdehyde and increasing T-AOC and T-SOD, without an effect on GSH-Px. These findings suggest that chronic D-galactose exposure induces neurodegeneration by enhancing caspase-mediated apoptosis and inhibiting neurogenesis and neuron migration, as well as increasing oxidative damage. In addition, D-galactose-induced toxicity in mice is a useful model for studying the mechanisms of neurodegeneration and neuroprotective drugs and agents.

Chronic systemic D-galactose exposure induces memory loss, neurodegeneration, and oxidative damage in mice: protective effects of R-alpha-lipoic acid

Chronic systemic exposure of D-galactose to mice, rats, and Drosophila causes the acceleration of senescence and has been used as an aging model. However, the underlying mechanism is as yet unclear. To investigate the mechanisms of neurodegeneration in this model, we studied cognitive function, hippocampal neuronal apoptosis and neurogenesis, and peripheral oxidative stress biomarkers and also the protective effects of the antioxidant R-alpha-lipoic acid. Chronic systemic exposure of mice to D-galactose (100 mg/kg, s.c., 7 weeks) induced a spatial memory deficit, an increase in cell karyopyknosis, apoptosis, and caspase-3 protein levels in hippocampal neurons, a decrease in the number of new neurons in the subgranular zone in the dentate gyrus, a reduction of migration of neural progenitor cells, and an increase in death of newly formed neurons in the granular cell layer. The D-galactose exposure also induced an increase in peripheral oxidative stress, including an increase in malondialdehyde and decreases in total antioxidative capabilities (T-AOC), total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-Px) activities. A concomitant treatment with lipoic acid ameliorated cognitive dysfunction and neurodegeneration in the hippocampus and also reduced peripheral oxidative damage by decreasing malondialdehyde and increasing T-AOC and T-SOD, without an effect on GSH-Px. These findings suggest that chronic D-galactose exposure induces neurodegeneration by enhancing caspase-mediated apoptosis and inhibiting neurogenesis and neuron migration, as well as increasing oxidative damage. In addition, D-galactose-induced toxicity in mice is a useful model for studying the mechanisms of neurodegeneration and neuroprotective drugs and agents.

Cardioprotection by intermittent fasting in rats

BACKGROUND

Intermittent fasting (IF), a dietary regimen in which food is available only every other day, increases the life span and reduces the incidence of age-associated diseases in rodents. We have reported neuroprotective effects of IF against ischemic injury of the brain. In this study, we examined the effects of IF on ischemic injury of the heart in rats.

METHODS AND RESULTS

After 3 months of IF or regular every-day feeding (control) diets started in 2-month-old rats, myocardial infarction (MI) was induced by coronary artery ligation. Twenty-four hours after MI, its size in the IF group was 2-fold smaller, the number of apoptotic myocytes in the area at risk was 4-fold less, and the inflammatory response was significantly reduced compared with the control diet group. Serial echocardiography revealed that during 10 weeks after MI (with continuation of the IF regimen), the left ventricular (LV) remodeling and MI expansion that were observed in the control diet group were absent in the IF group. In a subgroup of animals with similar MI size at 1 week after MI, further observation revealed less remodeling, better LV function, and no MI expansion in the IF group compared with the control group.

CONCLUSIONS

IF protects the heart from ischemic injury and attenuates post-MI cardiac remodeling, likely via antiapoptotic and antiinflammatory mechanisms.

Cognitive and behavioral assessment in dogs and pet food market applications

A multi-disciplinary program was developed to assess the efficacy of antioxidant inclusion in a canine pet food on cognitive decline in aged beagles. A systematic approach to development of the food was used prior to beginning the cognitive studies. Comprehensive evaluation of antioxidant ingredients included assessments of commodities with naturally occurring antioxidants and synthetic antioxidants not commonly utilized, or at different concentrations than what was commonly utilized, in commercial pet foods. Studies were conducted to insure stability through processing, absorption from the gastrointestinal tract, safety, and tests for potential antioxidant biological benefit by ex vivo tests. Testing of the antioxidant-fortified food in aged beagles slowed the rate of cognitive decline in aged dogs. In addition, environmental enrichment also slowed the rate of cognitive decline. Importantly, the combination of dietary antioxidants and environmental enrichment was synergistic and resulted in the least amount of cognitive decline over the 30-month study period. Finally, a clinical study showed that antioxidant fortified food improved age-related behavioral changes in older pet dogs at in-home situations.

Antioxidant status (selenium, vitamins A and E) and aging

Antioxidant status can be evaluated by blood selenium, vitamins A and E. The level of selenium was determined in whole blood, erythrocytes and plasma of 170 French people (70-95 years old) healthy and with intercurrent illness, by using PIXE (proton-induced X-ray emission analysis). These results are discussed with other values from the literature. Plasma levels of vitamins A and E have been measured by HPLC. All data were compared with those obtained for younger subjects. Healthy elderly people residing in a geriatric home received selenium supplements during 1 month. The influence of this supplementation brought to light a deficiency for this trace element. The correlation of aging and nutritional requirements with immune function, heart and cancer death rate is presented and discussed.

Energy balance, body size, and cancer

Increased energy intake and physical inactivity have been shown to heighten the risk of breast, large bowel, and other cancers. Large body size and fatness, as measured by adult stature, body weight and body mass indices, are positively related to a variety of cancers, including breast, colorectum, prostate, endometrium, kidney, and ovary, as well as to total cancer incidence or mortality in many investigations, although conflicting reports exist. Adult weight gain has also been specifically implicated in a few etiologic studies of breast and large bowel cancer. Furthermore, increased birthweight and childhood stature have been linked to increased risk of leukemia, lymphoma, osteogenic sarcoma, and central nervous system malignancies between infancy and young adulthood. Greater body weight also adversely affects breast cancer survival. These findings are complementary and support a role for positive energy balance in promoting human carcinogenesis. Potential mechanisms are discussed.

In vitro scavenger effect of dihydroquinoline type derivatives in different free radical generating systems

The non-toxic and water soluble dihydroquinoline type antioxidants: CH 402 (Na-2,2-dimethyl-1,2-dihydroquinoline-4-yl methane sulphonate) and MTDQ-DA (6,6-methylene bis 2,2-dimethyl-4-methane sulphonic acid: Na-1,2-dihydroquinoline) were studied in various in vitro tests in which oxygen free radicals were generated. Both compounds were shown to scavenge superoxide radical anions O2- produced in aqueous solution by pulse radiolysis with rate constants k (O2- + MTDQ-DA) = 4.10(8) dm3 mol-1 s-1 and k (O2- + CH 402) = 1.5.10(7) dm3 mol-1 s-1. CH 402 and MTDQ-DA reduced the H2O2 produced in the glucose-glucose oxidase reaction, which was detected by the luminol + hemin reaction with a chemiluminometric method. The dihydroquinoline type substrates inhibited the NADPH-induced and Fe3+ - stimulated lipid peroxidation and the ascorbic acid-induced non-enzymatic peroxidation pathways in microsomal fractions of rat and mouse liver.

Studies on catalase in ageing Zaprionus paravittiger (Diptera) with special reference to an antioxidant feeding

Zaprionus paravittiger fed with an antioxidant (sodium hypophosphite, 1 X 10(3) microM) supplemented diet exhibited adaptive compensatory responses in catalase activity (quantitative as well as qualitative). The longevity and catalase activity were found to be positively linked. The study denotes that free radical formation and antioxygenic defenses are closely associated and are the possible determinants of life span and ageing.

An antioxidant-induced life table modification and life-span prolongation in Zaprionus paravittiger (Diptera)

An antioxidant, sodium hypophosphite (SHP-1 X 10(3) microM), when added to the diet of Zaprionus paravittiger, induces various shifts in the age-related biochemical parameters. It maintains the viability of protein synthesis and normal energy-yielding processes through longer intervals besides decelerating the rate of loss of nucleic acids (Sharma and Wadhwa, 1986). Reduced body weight which indicates the low level of food restriction, and adaptive changes in amino acids and proteins, could be the important factors for the favourable effect of this antioxidant on life span.

Effects of oltipraz, BHA, ADT and cabbage on glutathione metabolism, DNA damage and lipid peroxidation in old mice

Eighteen-month-old female mice were fed defined diets for 2 weeks which contained 0.05% or 0.10% oltipraz, 0.10% anethole dithione (ADT), 0.10% butylated hydroxyanisole (BHA) or 20% lyophilized cabbage. All diets resulted in significant increases in hepatic reduced glutathione (GSH) content. Glutathione reductase and glutathione S-transferase activities were also significantly higher than the control values. All diets produced significant decreases in hepatic DNA damage (single strand breaks) and lipid peroxidation (malondialdehyde content). In general, similar effects were produced by the two dithiolthiones, oltipraz and ADT. More pronounced effects were produced by oltipraz and ADT than by BHA or cabbage in the diet. Diets high in antioxidants may be effective in retarding free radical reaction processes associated with aging and cancer.

Nutrition, cancer, and aging: an annotated review. I. Diet, carcinogenesis, and aging

The interrelationships of diet and carcinogenesis are discussed with the focus on aging. To establish whether the elderly are more susceptible to dietary carcinogens and whether dietary prevention of cancer is a reasonable goal for this population, the mechanisms of chemical carcinogenesis, the age-related metabolic and physiologic changes, and the current cancer preventive dietary strategies are reviewed. Vulnerability to dietary carcinogens results from a combination of factors that may increase or decrease the occurrence of cancer in the elderly, and it is, therefore, a very individualized feature, unpredictable when based solely on a subject's age. Dietary prevention of cancer may be effective in advanced age, and the dietary guidelines of the National Academy of Sciences should be implemented in this population.

Demential syndromes and the lipid metabolism

The present communication surveys the present knowledge about the extent to which formation of free radicals in the central nervous system may give rise to cross-linking reactions finally ending in the deposition of lipofuscin pigments. Free radicals may be formed by autoperoxidation of polyunsaturated fatty acids. These fatty acids, e.g., C22:6 omega 3, are enriched in rods and cones of the eye and in phosphatidyl ethanolamine of synaptosomes. By peroxidation, malondialdehyde is formed. This aldehyde may cross-link through amino groups of proteins and certain phospholipids. Hereby, lipofuscin is deposited. The peroxidation process is counteracted by certain enzymic systems and by antioxidants. Thus, glutathionperoxidase (GSH-Px), catalase and superoxid dismutase may eliminate peroxides. GSH-Px is a selenium-containing enzyme. Peroxides are also formed by metabolic transformation of dopamine. 3 demential syndromes, i.e. Alzheimer's, Parkinson's and Batten's diseases, are discussed with regard to whether the "free radical theory" may explain the pathogenesis. Finally, it is discussed whether an antioxidative treatment including vitamins E and C as well as a supplement of selenium, e.g. sodiumselenite, may be a therapeutic alternative to other types of treatment of demential syndromes or a direct supplement to the L-DOPA treatment of Parkinson's disease.

Disorder in human myelin induced by superoxide radical: an in vitro investigation

Potassium superoxide (KO.2), applied as a source of superoxide radical directly in vitro to white matter from young adult human brain, caused the lipid phase of the myelin to change from a crystalline (ordered) state to a liquid crystalline (disordered) state. The myelin transition temperature decreased from 65 degrees C to 37 degrees C. This alteration was accompanied by a dramatic increase in the levels of lipid peroxidation products--malondialdehyde, a conjugated diene, and ethane. These changes in human myelin, induced by direct application of O2-. radical, simulated myelin deterioration that occurs in the course of natural aging, thus, providing further substantiation for the notion that O2-. might be a major toxic agent associated with the aging process.

Changes in lipid phase behaviour in human myelin during maturation and aging. Involvement of lipid peroxidation

The biophysical properties of human myelin isolated from white matter of patients aged two months to 74 years were investigated using wide-angle X-ray diffraction. The myelin transition temperature increased from 13 degrees C to 65 degrees C as age increased from two months to 17 years, demonstrating an increase in the myelin lipid stability. Following this maturation period, the myelin transition temperature remained constant at 65 degrees C until age 50. Beyond age 50, the transition temperature of myelin decreased by 13 degrees C indicating that myelin stability decreased with aging. During this aging period, the levels of malondialdehyde and conjugated diene increased, indicating an increasing amount of lipid peroxidation. Although evidence is indirect, the results of this investigation strongly suggest that free radicals could be a primary factor in the acceleration of the aging processes in the human brain.