The biochemistry of aging

Phytochemical Characteristics and Anti-Inflammatory, Immunoregulatory, and Antioxidant Effects of Portulaca oleracea L.: A Comprehensive Review

Portulaca oleracea L. (P. oleracea) or purslane is a plant from the Portulacaceae family, which is used as food and traditional medicine for various diseases. This review article provides comprehensive information on the antioxidant, immunomodulatory, and anti-inflammatory properties of P. oleracea and its constituents. The literature survey of the different databases until the end of June 2023 was explored based on the keywords including the "P. oleracea, purslane, anti-inflammatory, immunomodulatory, and antioxidant properties." The plant contains flavonoids, alkaloids, terpenoids, fatty acids, vitamins, minerals, and some other compounds. The results indicated that P. oleracea and its constituents showed anti-inflammatory and immunomodulatory properties through reduction of inflammatory mediators including interferon gama (IFN-γ), interleukin (IL)-10, IL-4, tumor necrosis factor-alpha (TNF-α), and nitric oxide. Improvement in cytokines' serum levels (IFN-γ, IL-10, and IL-4) and increased IgG and IgM serum levels, as well as reduction of IgE, phospholipase A2, and total protein were demonstrated for P. oleracea. The plant and its constituents also improved oxidative stress by reduction of oxidant and increase of antioxidant markers. P. oleracea could be considered as an effective remedy for various inflammatory and immune diseases.

Glutathione: pharmacological aspects and implications for clinical use

Glutathione is a tripeptide found in many tissues which plays a pivotal role in critical physiological processes such as maintenance of redox balance, reduction of oxidative stress by enhancement of metabolic detoxification of both xenobiotic and endogenous compounds, and regulation of immune system function. Glutathione depletion is associated with many chronic degenerative diseases and loss of function with aging and altered glutathione metabolism has been implicated in central nervous system diseases, frailty and sarcopenia, infected state, chronic liver diseases, metabolic diseases, pulmonary and cardiovascular diseases. Therefore, the glutathione status may be an important biomarker and treatment target in various chronic, age-related diseases. Here we describe the main pharmacological aspects of glutathione, focusing on its synthesis and role in several vital functions including antioxidant defense, detoxification of xenobiotics and modulation of immune function and fibrogenesis and the clinical implications of its depletion and we discuss the different strategies for increasing glutathione cellular levels either by providing specific precursors and cofactors or directly administering the tripeptide.

PPARα Agonist, MHY3200, Alleviates Renal Inflammation during Aging via Regulating ROS/Akt/FoxO1 Signaling

PPARα is a ligand-dependent transcription factor and its activation is known to play an important role in cell defense through anti-inflammatory and antioxidant effects. MHY3200 (2-[4-(5-chlorobenzo[d]thiazol-2-yl)phenoxy]-2,2-difluoroacetic acid), a novel benzothiazole-derived peroxisome proliferator-activated receptor α (PPARα) agonist, is a synthesized PPARα activator. This study examined the beneficial effects of MHY3200 on age-associated alterations in reactive oxygen species (ROS)/Akt/forkhead box (FoxO) 1 signaling in rat kidneys. Young (7-month-old) and old (22-month-old) rats were treated with MHY3200 (1 mg/kg body weight/day or 3 mg/kg body weight/day) for two weeks. MHY3200 treatment led to a notable decrease in triglyceride and insulin levels in serum from old rats. The elevated kidney ROS level, serum insulin level, and Akt phosphorylation in old rats were reduced following MHY3200 treatment; moreover, FoxO1 phosphorylation increased. MHY3200 treatment led to the increased level of FoxO1 and its target gene, MnSOD. MHY3200 suppressed cyclooxygenase-2 expression by activating PPARα and inhibiting the activation of nuclear factor-κB (NF-κB) in the kidneys of old rats. Our results suggest that MHY3200 ameliorates age-associated renal inflammation by regulating NF-κB and FoxO1 via ROS/Akt signaling.

The Relationship between Oxidative Stress and Anxiety in a Healthy Older Population

Background/study context: F₂-Isoprostanes are putative markers of oxidative stress, one of the processes associated with biological senescence. Evidence exists for elevated F₂-Isoprostanes in chronic conditions including psychiatric disorders. Few studies have examined the relationship between oxidative stress and mood in older healthy samples, to establish the influence on mental health. Given current aging demographics in many nations, management of brain and mental health is crucial for longevity, chronic disease management, and quality of life.Method: We investigated the relationship between F₂-Isoprostanes, a marker for oxidative stress, and anxiety and mood in 262 healthy adults aged 60-75 years, using baseline data from the Australian Research Council Longevity Intervention (ARCLI; ANZCTR12611000487910), a 12-month nutraceutical intervention study.Results: Higher F2 levels significantly predicted increased Depression-dejection and Anger-hostility subscale scores from the Profile of Mood States (POMS). Fatigue-inertia subscale was predicted by increased Body Mass Index. Spielberger State-Trait Inventory (STAI) scores were significantly higher in females.Conclusion: While the primary outcome data did not find a definitive relationship between F2 and total mood or general anxiety levels, the sub-scale data adds weight toward growing literature that biological processes such as oxidative stress are in part related to mood. This is a modifiable risk factor contributing to physical and mental wellbeing that are crucial to healthy aging.

Correlations between resistance training-induced changes on phase angle and biochemical markers in older women

The main purpose of this study was to investigate the effects of 12 weeks of resistance training (RT) on phase angle (PhA), inflammatory and oxidative stress biomarkers, and to evaluate whether these RT-induced adaptations are related to PhA changes. Fifty-one older women (70.6 ± 5.1 years; 26.9 ± 4.2 kg/m² ) were randomly allocated into a training group (TG) that performed 12-week RT or a nonexercising control group (CG). The PhA (Xitron), body composition (DXA), and blood sample measurements (after a 12 hours fast) were performed before and after the intervention. The TG showed a significant (P < .05) increase in PhA (TG: +7.4±5.9% vs CG: -3.6 ± 8.8%), and interleukin-10 (IL-10; TG: +51.8 ± 71.1% vs CG: -46.6 ± 38.0%), and a decrease in tumor necrosis factor alpha (TNF-α; TG: -15.2 ± 11.1% vs CG: +6.9±17.7%), interleukin-6 (IL-6; TG: -17.9 ± 17.8% vs CG: +6.1 ± 24.8%), and C-reactive protein (CRP; TG: -24.1 ± 19.9% vs CG: +43.8 ± 31.1%). Moreover, TG upregulated catalase (TG: +11.4 ± 15.0% vs CG: -6.7 ± 10.2%). Changes in TNF-α (r = -.71), CRP (r = -.65), lower advanced oxidation protein products (r = -.55), and catalase (r = +.73) after RT were correlated with changes in PhA (P < .05). These results suggest that RT improves PhA, inflammatory and oxidative stress biomarkers, and the changes in inflammatory and oxidative damage markers are correlated with changes in PhA.

Consequences of Inadequate Intakes of Vitamin A, Vitamin B12, Vitamin D, Calcium, Iron, and Folate in Older Persons

Purpose of Review

This review broadly discusses the consequences of inadequate consumption, by deficit or excess, of selected micronutrients on the quality of life and morbidity during aging, specifically considering increases in life expectancy and the costs of care in the older persons.

Recent Findings

A literature review of the periods 2012 to 2018, focusing on vitamins A, B₁₂, and D, calcium, iron and folate, was completed as these micronutrients are found to significantly affect the aging process. Causation and application of these micronutrients to disorders related to aging are controversial and mixed. This review highlights research needs and controversial points on the role of these micronutrients.

Summary

Micronutrient deficiencies are a common and avoidable contributor to decreased quality of life and healthcare costs in the older persons. Further research is needed to determine adequate intakes and innovative uses, including appropriate thresholds for improved health outcomes for this population.

Iron overload exacerbates age-associated cardiac hypertrophy in a mouse model of hemochromatosis

Cardiac damage associated with iron overload is the most common cause of morbidity and mortality in patients with hereditary hemochromatosis, but the precise mechanisms leading to disease progression are largely unexplored. Here we investigated the effects of iron overload and age on cardiac hypertrophy using 1-, 5- and 12-month old Hfe-deficient mice, an animal model of hemochromatosis in humans. Cardiac iron levels increased progressively with age, which was exacerbated in Hfe-deficient mice. The heart/body weight ratios were greater in Hfe-deficient mice at 5- and 12-month old, compared with their age-matched wild-type controls. Cardiac hypertrophy in 12-month old Hfe-deficient mice was consistent with decreased alpha myosin and increased beta myosin heavy chains, suggesting an alpha-to-beta conversion with age. This was accompanied by cardiac fibrosis and up-regulation of NFAT-c2, reflecting increased calcineurin/NFAT signaling in myocyte hypertrophy. Moreover, there was an age-dependent increase in the cardiac isoprostane levels in Hfe-deficient mice, indicating elevated oxidative stress. Also, rats fed high-iron diet demonstrated increased heart-to-body weight ratios, alpha myosin heavy chain and cardiac isoprostane levels, suggesting that iron overload promotes oxidative stress and cardiac hypertrophy. Our findings provide a molecular basis for the progression of age-dependent cardiac stress exacerbated by iron overload hemochromatosis.

Mechanism of Action of Prolyl Oligopeptidase (PREP) in Degenerative Brain Diseases: Has Peptidase Activity Only a Modulatory Role on the Interactions of PREP with Proteins?

In the aging brain, the correct balance of neural transmission and its regulation is of particular significance, and neuropeptides have a significant role. Prolyl oligopeptidase (PREP) is a protein highly expressed in brain, and evidence indicates that it is related to aging and in neurodegenration. Although PREP is regarded as a peptidase, the physiological substrates in the brain have not been defined, and after intense research, the molecular mechanisms where this protein is involved have not been defined. We propose that PREP functions as a regulator of other proteins though peptide gated direct interaction. We speculate that, at least in some processes where PREP has shown to be relevant, the peptidase activity is only a consequence of the interactions, and not the main physiological activity.

Lens glutathione homeostasis: Discrepancies and gaps in knowledge standing in the way of novel therapeutic approaches

Cataract is the major cause of blindness worldwide. The WHO has estimated around 20 million people have bilateral blindness from cataract, and that number is expected to reach 50 million in 2050. The cataract surgery is currently the main treatment approach, though often associated with complications, such as Posterior Capsule Opacification (PCO)-also known as secondary cataract. The lens is an avascular ocular structure equipped with an unusually high level of glutathione (GSH), which plays a vital role in maintaining lens transparency by regulating lenticular redox state. The lens epithelium and outer cortex are thought to be responsible for providing the majority of lens GSH via GSH de novo synthesis, assisted by a continuous supply of constituent amino acids from the aqueous humor, as well as extracellular GSH recycling from the gamma-glutamyl cycle. However, when de novo synthesis is impaired, in the presence of low GSH levels, as in the aging human lens, compensatory mechanisms exist, suggesting that the lens is able to uptake GSH from the surrounding ocular tissues. However, these uptake mechanisms, and the GSH source and its origin, are largely unknown. The lens nucleus does not have the ability to synthesize its own GSH and fully relies on transport from the outer cortex by yet unknown mechanisms. Understanding how aging reduces GSH levels, particularly in the lens nucleus, how it is associated with age-related nuclear cataract (ARNC), and how the lens compensates for GSH loss via external uptake should be a major research priority. The intent of this review, which is dedicated to the memory of David C. Beebe, is to summarize our current understanding of lens GSH homeostasis and highlight discrepancies and gaps in knowledge that stand in the way of pharmacologically minimizing the impact of declining GSH content in the prevention of age-related cataract.

Chongcao-Shencha Attenuates Liver and Kidney Injury through Attenuating Oxidative Stress and Inflammatory Response in D-Galactose-Treated Mice

The Chongcao-Shencha (CCSC), a Chinese herbal compound formula, has been widely used as food material and medicine for enhancing physical strength. The present study investigated the possible effect of CCSC in alleviating the liver and kidney injury in D-galactose- (D-gal-) treated mice and the underlying mechanism. Mice were given a subcutaneous injection of D-gal (200 mg/kg) and orally administered CCSC (200, 400, and 800 mg/kg) daily for 8 weeks. Results indicated that CCSC increased the depressed body weight and organ index induced by D-gal, ameliorated the histological deterioration, and decreased the levels of ALT, AST, BUN, and CRE as compared with D-gal group. Furthermore, CCSC not only elevated the activities of antioxidant enzymes SOD, CAT, and GPx but also upregulated the mRNA expression of SOD1, CAT, and GPx1, while decreasing the MDA level in D-gal-treated mice. Results of western blotting analysis showed that CCSC significantly inhibited the upregulation of expression of nuclear factor kappa B (NF-κB) p65, p-p65, p-IκBα, COX2, and iNOS and inhibited the downregulation of IκBα protein expression caused by D-gal. This study demonstrated that CCSC could attenuate the liver and kidney injury in D-gal-treated mice, and the mechanism might be associated with attenuating oxidative stress and inflammatory response.

Immune-Relevant and Antioxidant Activities of Vitellogenin and Yolk Proteins in Fish

Vitellogenin (Vtg), the major egg yolk precursor protein, is traditionally thought to provide protein- and lipid-rich nutrients for developing embryos and larvae. However, the roles of Vtg as well as its derived yolk proteins lipovitellin (Lv) and phosvitin (Pv) extend beyond nutritional functions. Accumulating data have demonstrated that Vtg, Lv and Pv participate in host innate immune defense with multifaceted functions. They can all act as multivalent pattern recognition receptors capable of identifying invading microbes. Vtg and Pv can also act as immune effectors capable of killing bacteria and virus. Moreover, Vtg and Lv are shown to possess phagocytosis-promoting activity as opsonins. In addition to these immune-relevant functions, Vtg and Pv are found to have antioxidant activity, which is able to protect the host from oxidant stress. These non-nutritional functions clearly deepen our understanding of the physiological roles of the molecules, and at the same time, provide a sound basis for potential application of the molecules in human health.

Lipofuscin in saliva and plasma and its association with age in healthy adults

BACKGROUND AND AIM

To compare blood and salivary levels of lipofuscin in healthy adults and to analyze the relationship between the lipofuscin level and the healthy adults' age.

METHODS

One hundred and twenty-two healthy volunteers were recruited and divided into three groups according to their age: young (n = 42, 20-44 years old), middle-aged (n = 51, 45-59 years old), and elderly (n = 29, 60-74 years old). One ml saliva and 5 ml whole blood were collected from each person. An ELISA kit was used to measure both the plasma and salivary lipofuscin levels. The differences between the groups were compared with independent-sample t test, and the relationship between the salivary lipofuscin level and the age was assessed with linear regression analysis.

RESULTS

The mean ± SD of the lipofuscin level in the saliva and plasma of 122 subjects was 68.93 ± 1.32 and 78.05 ± 1.75 μmol/l, respectively. No gender-dependent differences were observed in either the salivary or the plasma lipofuscin level (saliva: p = 0.443, plasma: p = 0.459). The salivary and plasma lipofuscin levels of the elderly subjects were significantly higher than those of the young (saliva: 80.72 ± 13.53 mmol/l versus 59.12 ± 1.92 mmol/l, p = 0.0003; plasma: 93.31 ± 3.14 mmol/l versus 67.43 ± 2.54 mmol/l, p = 0.0002) and middle-aged (saliva: 80.72 ± 13.53 mmol/l versus 70.31 ± 11.17 mmol/l, p = 0.0004; plasma: 93.31 ± 3.14 mmol/l versus 78.12 ± 2.40 mmol/l, p = 0.0002) subjects. Similarly, the salivary and plasma lipofuscin levels of the middle-aged subjects were significantly higher than those of the young subjects (saliva: 70.31 ± 11.17 mmol/l versus 59.12 ± 1.92 mmol/l, p < 0.0001; plasma: 78.12 ± 2.40 mmol/l versus 67.43 ± 2.54 mmol/l, p = 0.0019). The lipofuscin levels in the saliva and plasma were significantly positively correlated with the subject age (r = 0.551, p = 0.0001; r = 0.528, p < 0.0001). Furthermore, the salivary lipofuscin level and plasma lipofuscin level also were found to have a positive correlation (r = 0.621, p < 0.0001).

CONCLUSION

No gender-dependent differences were observed in either the salivary or plasma lipofuscin levels. The salivary and plasma lipofuscin levels were positively correlated, and the age is positively correlated with lipofuscin content in saliva.

Oxidative stress and mitochondrial failure in the pathogenesis of glaucoma neurodegeneration

This review focuses on oxidative stress and mitochondrial failure for understanding mechanisms of optic nerve damage in primary open-angle glaucoma. The chapter shows scientific evidence for the role of mitochondrial disbalance and reactive oxygen species in glaucoma neurodegeneration. Mitochondria regulate important cellular functions including reactive oxygen species generation and apoptosis. Mitochondrial alterations result from a wide variety of damaging sources. Reactive oxygen species formed by the mitochondria can act as signaling molecules, inducing lipid peroxidation and/or excitotoxicity with the result of cell lesion and death. Antioxidants may help to counteract oxidative stress and to promote neuroprotection. We provide information that may lead to a new way for diagnosing and treating glaucoma patients.

Tissue formation and tissue engineering through host cell recruitment or a potential injectable cell-based biocomposite with replicative potential: Molecular mechanisms controlling cellular senescence and the involvement of controlled transient telomerase activation therapies

Accumulated data indicate that wound-care products should have a composition equivalent to that of the skin: a combination of particular growth factors and extracellular matrix (ECM) proteins endogenous to the skin, together with viable epithelial cells, fibroblasts, and mesenchymal stem cells (MSCs). Strategies consisting of bioengineered dressings and cell-based products have emerged for widespread clinical use; however, their performance is not optimal because chronic wounds persist as a serious unmet medical need. Telomerase, the ribonucleoprotein complex that adds telomeric repeats to the ends of chromosomes, is responsible for telomere maintenance, and its expression is associated with cell immortalization and, in certain cases, cancerogenesis. Telomerase contains a catalytic subunit, the telomerase reverse transcriptase (hTERT). Introduction of TERT into human cells extends both their lifespan and their telomeres to lengths typical of young cells. The regulation of TERT involves transcriptional and posttranscriptional molecular biology mechanisms. The manipulation, regulation of telomerase is multifactorial in mammalian cells, involving overall telomerase gene expression, post-translational protein-protein interactions, and protein phosphorylation. Reactive oxygen species (ROS) have been implicated in aging, apoptosis, and necrosis of cells in numerous diseases. Upon production of high levels of ROS from exogenous or endogenous generators, the redox balance is perturbed and cells are shifted into a state of oxidative stress, which subsequently leads to modifications of intracellular proteins and membrane lipid peroxidation and to direct DNA damage. When the oxidative stress is severe, survival of the cell is dependent on the repair or replacement of damaged molecules, which can result in induction of apoptosis in the injured with ROS cells. ROS-mediated oxidative stress induces the depletion of hTERT from the nucleus via export through the nuclear pores. Nuclear export is initiated by ROS-induced phosphorylation of tyrosine 707 within hTERT by the Src kinase family. It might be presumed that protection of mitochondria against oxidative stress is an important telomere length-independent function for telomerase in cell survival. Biotechnology companies are focused on development of therapeutic telomerase vaccines, telomerase inhibitors, and telomerase promoter-driven cell killing in oncology, have a telomerase antagonist in late preclinical studies. Anti-aging medicine-oriented groups have intervened on the market with products working on telomerase activation for a broad range of degenerative diseases in which replicative senescence or telomere dysfunction may play an important role. Since oxidative damage has been shown to shorten telomeres in tissue culture models, the adequate topical, transdermal, or systemic administration of antioxidants (such as, patented ocular administration of 1% N-acetylcarnosine lubricant eye drops in the treatment of cataracts) may be beneficial at preserving telomere lengths and delaying the onset or in treatment of disease in susceptible individuals. Therapeutic strategies toward controlled transient activation of telomerase are targeted to cells and replicative potential in cell-based therapies, tissue engineering and regenerative medicine.

Zebrafish phosvitin is an antioxidant with non-cytotoxic activity

Antioxidants, or anti-oxidant agents, have attracted a great deal of attention in recent years because of their roles in prevention of chronic diseases and utilization as preservatives in food and cosmetics. In this study, we clearly demonstrated that zebrafish recombinant phosvitin (rPv) is an antioxidant agent capable of inhibiting the oxidation of the linoleic acid, and scavenging the 2,2-diphenyl-1-picrylhydrazyl radical. We also showed that zebrafish rPv is a cellular antioxidant capable of protecting radical-mediated oxidation of cellular biomolecules. Importantly, zebrafish rPv is non-cytotoxic to murine macrophage RAW264.7 cells. It is the first report that showed the antioxidant activities of Pv in fishes, suggesting that zebrafish Pv can be an important antioxidant, which can be used as preservatives in food and cosmetics and even as supplementary mediator in different diseased states.

Yulangsan polysaccharide improves redox homeostasis and immune impairment in d-galactose-induced mimetic aging

Yulangsan polysaccharide (YLSP) is a traditional Chinese medicine used in long-term treatment as a modulator of brain dysfunction and immunity.

Phloroglucinol Attenuates Free Radical-induced Oxidative Stress

The protective role of phloroglucinol against oxidative stress and stress-induced premature senescence (SIPS) was investigated in vitro and in cell culture. Phloroglucinol had strong and concentration-dependent radical scavenging effects against nitric oxide (NO), superoxide anions (O₂⁻), and hydroxyl radicals. In this study, free radical generators were used to induce oxidative stress in LLC-PK1 renal epithelial cells. Treatment with phloroglucinol attenuated the oxidative stress induced by peroxyl radicals, NO, O₂⁻, and peroxynitrite. Phloroglucinol also increased cell viability and decreased lipid peroxidation in a concentration-dependent manner. WI-38 human diploid fibroblast cells were used to investigate the protective effect of phloroglucinol against hydrogen peroxide (H₂O₂)-induced SIPS. Phloroglucinol treatment attenuated H₂O₂-induced SIPS by increasing cell viability and inhibited lipid peroxidation, suggesting that treatment with phloroglucinol should delay the aging process. The present study supports the promising role of phloroglucinol as an antioxidative agent against free radical-induced oxidative stress and SIPS.

Antioxidant effect of zinc supplementation on both plasma and cellular red-ox status markers in a group of elderly Italian population

OBJECTIVES

The aim of this work was to evaluate the effect of long term supplementation with two moderate dose of Zn on plasma and cellular red-ox status markers in elderly volunteers.

DESIGN, SETTING AND SUBJECTS

In a double blind study 108 healthy volunteers, aged 70-85 years, were enrolled. They were randomly divided in 3 groups of treatment, receiving placebo, 15 mg/day and 30 mg/day of Zn for 6 months. Red-ox status markers were assessed at baseline and after 6 months evaluating carotenoids, vitamin A and E in plasma; glutathione (GSH), thiol groups (RSH), malondialdehyde (MDA), percentage of haemolysis and methemoglobin in erythrocytes.

RESULTS

Zn supplementation had no significant effects on red-ox status markers except for vitamin A levels (from 1.94±0.44 to 2.18±0.48 μM in volunteers receiving 15 mg of Zn and from 1.95±0.46 to 2.26±0.56 μM in volunteers receiving 30 mg of Zn), which increased proportionally to zinc dose.

CONCLUSIONS

It appears that, differently from unhealthy populations, long-term supplementation with two moderate doses of Zn in a healthy elderly population, with an adequate Zn nutritive status and macro and micronutrients intakes in the range of normality, is an inefficient way to increase antioxidant defences.

Morphological changes and altered expression of antioxidant proteins in a heterozygous dynein mutant; a mouse model of spinal muscular atrophy

OBJECTIVE

There is increased evidence that oxidative stress is involved in exacerbations of neurodegenerative diseases and spinal muscular atrophies.

METHODS

We examined changes in morphology and expression of antioxidant proteins and peroxiredoxins in motor neurons of lumbar spinal cord, dorsal root ganglion sensory neurons, macroglial cells and quadriceps muscles of newborn heterozygous Loa/+ mice ("legs at odd angles"), a mouse model for early onset of the spinal muscular atrophy with lower extremity predominance (SMA-LED).

RESULTS

Our data indicate that newborn Loa-mice develop: neuroinflammation of the sensory and motor neurons; muscular inflammation with atrophic and denervated myofibers; increased expression of neuronal mitochondrial peroxiredoxins (Prxs) 3, 5 and cytoplasmic Prx 6 in motor and sensory neurons, myofibers, fibroblasts of perimysium and chondrocytes of cartilage; and decreased expression of Prx 6 by glial cells and in extracellular space surrounding motor neurons.

CONCLUSION

The decrease in expression of Prx 6 by glial cells and extracellular Prx 6 secretion in early stages of the pathological conditions is consistent with the hypothesis that chronic oxidative stress may lead to neurodegeneration of motor neurons and exacerbation of the pathology.

Adrenergic signaling and oxidative stress: a role for sirtuins?

The adrenergic system plays a central role in stress signaling and stress is often associated with increased production of ROS. However, ROS overproduction generates oxidative stress, that occurs in response to several stressors. β-adrenergic signaling is markedly attenuated in conditions such as heart failure, with downregulation and desensitization of the receptors and their uncoupling from adenylyl cyclase. Transgenic activation of β2-adrenoceptor leads to elevation of NADPH oxidase activity, with greater ROS production and p38MAPK phosphorylation. Inhibition of NADPH oxidase or ROS significantly reduced the p38MAPK signaling cascade. Chronic β2-adrenoceptor activation is associated with greater cardiac dilatation and dysfunction, augmented pro-inflammatory and profibrotic signaling, while antioxidant treatment protected hearts against these abnormalities, indicating ROS production to be central to the detrimental signaling of β2-adrenoceptors. It has been demonstrated that sirtuins are involved in modulating the cellular stress response directly by deacetylation of some factors. Sirt1 increases cellular stress resistance, by an increased insulin sensitivity, a decreased circulating free fatty acids and insulin-like growth factor (IGF-1), an increased activity of AMPK, increased activity of PGC-1a, and increased mitochondrial number. Sirt1 acts by involving signaling molecules such P-I-3-kinase-Akt, MAPK and p38-MAPK-β. βAR stimulation antagonizes the protective effect of the AKT pathway through inhibiting induction of Hif-1α and Sirt1 genes, key elements in cell survival. More studies are needed to better clarify the involvement of sirtuins in the β-adrenergic response and, overall, to better define the mechanisms by which tools such as exercise training are able to counteract the oxidative stress, by both activation of sirtuins and inhibition of GRK2 in many cardiovascular conditions and can be used to prevent or treat diseases such as heart failure.

Adrenergic signaling and oxidative stress: a role for sirtuins?

The adrenergic system plays a central role in stress signaling and stress is often associated with increased production of ROS. However, ROS overproduction generates oxidative stress, that occurs in response to several stressors. β-adrenergic signaling is markedly attenuated in conditions such as heart failure, with downregulation and desensitization of the receptors and their uncoupling from adenylyl cyclase. Transgenic activation of β2-adrenoceptor leads to elevation of NADPH oxidase activity, with greater ROS production and p38MAPK phosphorylation. Inhibition of NADPH oxidase or ROS significantly reduced the p38MAPK signaling cascade. Chronic β2-adrenoceptor activation is associated with greater cardiac dilatation and dysfunction, augmented pro-inflammatory and profibrotic signaling, while antioxidant treatment protected hearts against these abnormalities, indicating ROS production to be central to the detrimental signaling of β2-adrenoceptors. It has been demonstrated that sirtuins are involved in modulating the cellular stress response directly by deacetylation of some factors. Sirt1 increases cellular stress resistance, by an increased insulin sensitivity, a decreased circulating free fatty acids and insulin-like growth factor (IGF-1), an increased activity of AMPK, increased activity of PGC-1a, and increased mitochondrial number. Sirt1 acts by involving signaling molecules such P-I-3-kinase-Akt, MAPK and p38-MAPK-β. βAR stimulation antagonizes the protective effect of the AKT pathway through inhibiting induction of Hif-1α and Sirt1 genes, key elements in cell survival. More studies are needed to better clarify the involvement of sirtuins in the β-adrenergic response and, overall, to better define the mechanisms by which tools such as exercise training are able to counteract the oxidative stress, by both activation of sirtuins and inhibition of GRK2 in many cardiovascular conditions and can be used to prevent or treat diseases such as heart failure.

A cytoprotective perspective on longevity regulation

There are many mechanisms of lifespan extension, including the disruption of insulin/insulin-like growth factor 1 (IGF-1) signaling, metabolism, translation, and feeding. Despite the disparate functions of these pathways, inhibition of each induces responses that buffer stress and damage. Here, emphasizing data from genetic analyses in Caenorhabditis elegans, we explore the effectors and upstream regulatory components of numerous cytoprotective mechanisms activated as major elements of longevity programs, including detoxification, innate immunity, proteostasis, and oxidative stress response. We show that their induction underpins longevity extension across functionally diverse triggers and across species. Intertwined with the evolution of longevity, cytoprotective pathways are coupled to the surveillance of core cellular components, with important implications in normal and aberrant responses to drugs, chemicals, and pathogens.

Effect of Colla corii asini (E'jiao) on D-galactose induced aging mice

Colla corii asini (E'jiao), donkey-hide gelatin prepared by stewing and concentrating from Equus asinus L. donkey hide, is a traditional Chinese medicine preparation widely used in clinical hematic antanemic therapy in China. The aim of the present study was to investigate potential anti-aging effect of Colla corii asini and explore related mechanisms in D-galactose (gal) induced aging model mice. The mice were artificially induced aging by subcutaneously injection with D-gal at the dose of 100 mg/kg·d for 8 weeks. Colla corii asini was simultaneously treated to them once daily by intragastric gavage. Appetite, mental condition, body weight, and organ index were observed. Activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), as well as levels of malondialdehyde (MDA) in serum, brain, and liver were determined by according assay kits. Western blotting analysis was used to detect p16 and p21 expression. Results indicated that Colla corii asini could improve appetite, mental condition, body weight, and organ condition of model mice, improve SOD, CAT, and GSH-Px activities, reduce MDA levels, and modulate age-related genes expression in D-gal induced mice. Therefore, Colla corii asini may have effect to suppress the aging process through enhancing antioxidant activity, scavenging free radicals, and modulating aging-related gene expression.

Mitochondrial Bioenergetics, Diabetes, and Aging: Top-Down Analysis Using the Diabetic Goto-Kakizaki (GK) Rat as a Model

In the present study we investigated the changes in the oxidative phosphorylation system of liver mitochondria, isolated from diabetic Goto-Kakizaki (GK) and Wistar (control) rats with different ages (6, 12, 26, and 52 weeks). We used a kinetic approach known as "top-down" analysis, which conceptually divides the oxidative phosphorylation system into two subsystems: one producing the protonmotive force (Deltap) and another that consumes Deltap. The overall response of the Deltap generators to Deltap was obtained from an uncoupler titration of respiration rate versus Deltap, while the overall response of Deltap consumers to Deltap was obtained from an inhibitor titration of respiration rate versus Deltap. Our results showed that GK liver mitochondrial preparations presented an increase in Deltap production and phosphorylative subsystems (using succinate as respiratory substrate). The alterations observed may suggest the existence of biochemical compensatory mechanisms to type 2 diabetes mellitus in GK rats during their first year of life, in order to reduce the injury associated with the disease. Furthermore, we observed that liver metabolic efficiency of mitochondrial respiration declined with age, this decrease in respiratory activity being visible both in control and diabetic rats.

Cordycepin (3'-deoxyadenosine) attenuates age-related oxidative stress and ameliorates antioxidant capacity in rats

Free radical-induced oxidative damage is considered to be the most important consequence of the aging process. The activities and capacities of antioxidant systems of cells decline with increased age, leading to the gradual loss of pro-oxidant/antioxidant balance and resulting in increased oxidative stress. Our investigation was focused on the effects of cordycepin (3'-deoxyadenosine) on lipid peroxidation and antioxidation in aged rats. Age-associated decline in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), reduced glutathione (GSH), vitamin C and vitamin E, and elevated levels of malondialdehyde (MDA) were observed in the liver, kidneys, heart and lungs of aged rats, when compared to young rats. Furthermore, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, and creatinine were found to be significantly elevated in aged rats compared to young rats. Aged rats receiving cordycepin treatment show increased activity of SOD, CAT, GPx, GR and GST, and elevated levels of GSH, and vitamins C and E such that the values of most of these parameters did not differ significantly from those found in young rats. In addition, the levels of MDA, AST, ALT, urea and creatinine became reduced upon administration of cordycepin to aged rats. These results suggest that cordycepin is effective for restoring antioxidant status and decreasing lipid peroxidation in aged rats.

Diuretic use is associated with better learning and memory in older adults in the Ginkgo Evaluation of Memory Study

BACKGROUND

To investigate the association between diuretics, angiotensin-converting enzyme inhibitors (ACE-I), angiotensin II receptor blockers (AT2RB), and cognitive function.

METHODS

This post hoc analysis of the randomized controlled Ginkgo Evaluation of Memory Study trial focuses on 3069 nondemented community-dwelling participants aged >75 years. At baseline visit, detailed information about medication use was collected and five cognitive domains were assessed. Multivariate linear regression analyses were used to assess cross-sectional associations between medication use and cognitive function.

RESULTS

In all, 36% of participants reported history of hypertension and 53% reported antihypertensive medication use, with 17% reporting diuretic, 11% ACE-I, and 2% AT2RB use. Potassium-sparing diuretic use (N = 192) was associated with better verbal learning and memory measured by California Verbal Learning Test as compared with no antihypertensive medication users (β = 0.068, P = .01; β = 0.094, P < .001) and other antihypertensive medication users (β = 0.080, P = .03; β = 0.153, P < .001). Use of ACE-I or AT2RB was not associated with better cognitive function.

CONCLUSION

Results warrant further investigation into possible protective effects of potassium-sparing diuretics and the role of potassium in mitigating cognitive decline.

Polysaccharides from the Medicinal Mushroom Cordyceps taii Show Antioxidant and Immunoenhancing Activities in a D-Galactose-Induced Aging Mouse Model

Cordyceps taii, an edible medicinal mushroom native to south China, is recognized as an unparalleled resource of healthy foods and drug discovery. In the present study, the antioxidant pharmacological properties of C. taii were systematically investigated. In vitro assays revealed the scavenging activities of the aqueous extract and polysaccharides of C. taii against various free radicals, that is, 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and superoxide anion radical. The EC₅₀ values for superoxide anion-free radical ranged from 2.04 mg/mL to 2.49 mg/mL, which was at least 2.6-fold stronger than that of antioxidant thiourea. The polysaccharides also significantly enhanced the antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase) and markedly decreased the malondialdehyde production of lipid peroxidation in a D-galactose-induced aging mouse model. Interestingly, the immune function of the administration group was significantly boosted compared with the D-galactose-induced aging model group. Therefore, the C. taii polysaccharides possessed potent antioxidant activity closely associated with immune function enhancement and free radical scavenging. These findings suggest that the polysaccharides are a promising source of natural antioxidants and antiaging drugs. Consequently, a preliminary chemical investigation was performed using gas chromatography-mass spectroscopy and revealed that the polysaccharides studied were mainly composed of glucose, mannose, and galactose. Fourier-transform infrared spectra also showed characteristic polysaccharide absorption bands.

The Functions of PPARs in Aging and Longevity

Peroxisome proliferator-activated receptors (PPARs) are key regulators in various age-associated pathophysiological processes related to energy metabolism and oxidative stress. A progressive rise of oxidative stress and related inflammatory reaction appears the hallmarks of the aging process and many age-related diseases. PPARs are important redox-sensitive transcription factors and their dyregulated activations seem to be major culprits for these pathological processes. Drugs targeting PPARs activity are already in widespread clinical use; however, based on these concepts, this review highlights the understanding of the role of PPARs in aging and indicates the necessary particular attention for the potential therapeutic uses of current PPAR agonists in age-associated diseases.

Alzheimer's disease is not "brain aging": neuropathological, genetic, and epidemiological human studies

Human studies are reviewed concerning whether "aging"-related mechanisms contribute to Alzheimer's disease (AD) pathogenesis. AD is defined by specific neuropathology: neuritic amyloid plaques and neocortical neurofibrillary tangles. AD pathology is driven by genetic factors related not to aging per se, but instead to the amyloid precursor protein (APP). In contrast to genes involved in APP-related mechanisms, there is no firm connection between genes implicated in human "accelerated aging" diseases (progerias) and AD. The epidemiology of AD in advanced age is highly relevant but deceptively challenging to address given the low autopsy rates in most countries. In extreme old age, brain diseases other than AD approximate AD prevalence while the impact of AD pathology appears to peak by age 95 and decline thereafter. Many distinct brain diseases other than AD afflict older human brains and contribute to cognitive impairment. Additional prevalent pathologies include cerebrovascular disease and hippocampal sclerosis, both high-morbidity brain diseases that appear to peak in incidence later than AD chronologically. Because of these common brain diseases of extreme old age, the epidemiology differs between clinical "dementia" and the subset of dementia cases with AD pathology. Additional aging-associated mechanisms for cognitive decline such as diabetes and synapse loss have been linked to AD and these hypotheses are discussed. Criteria are proposed to define an "aging-linked" disease, and AD fails all of these criteria. In conclusion, it may be most fruitful to focus attention on specific pathways involved in AD rather than attributing it to an inevitable consequence of aging.

Age-Related Blood Antioxidant Capacity in Men and Women

The aim of the study was to assess the blood antioxidant capacity in men and women in relation to age. The subjects were 19 men (YM) and 19 women (YW) aged 25-32 years, and 11 men (OM) and 11 women (OW) aged 63-71 years, all sedentary. The following factors were determined: the activity of erythrocyte superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPX), catalase (CAT), total antioxidant status (TAS), as well as plasma retinol, α-tocopherol, uric acid and total protein concentrations. The sum of standardized activities of antioxidant enzymes was calculated to compare age-related changes in the total capacity of the erythrocyte antioxidant defense. No significant age-related changes in SOD activity were observed; mean CAT activity was higher in older women and men than in younger subjects. Mean activity of GPX was higher and that of GR lower in older subjects compared to the younger ones. The calculated total erythrocyte antioxidant enzyme capacity in younger and older subjects rendered similar values. No significant differences in plasma retinol and α-tocopherol concentrations in relation to sex or age were noted. The plasma total protein level was significantly lower in younger women and men compared to their older mates. It was concluded that the total erythrocyte enzymatic antioxidant capacity did not change with age. The results obtained clearly show that multiple factors may contribute to the ageing process.

Vitamin E and immunity

Vitamin E is the most important chain-breaking, lipid-soluble antioxidant present in body tissues of all cells and is considered the first line of defense against lipid peroxidation and it is important for normal function of the immune cells. However, vitamin E deficiency is rare in well-nourished healthy subjects and is not a problem, even among people living on relatively poor diets, both T- and B-cell functions are impaired by vitamin E deficiency. While immune cells are particularly enriched in vitamin E because of their high polyunsaturated fatty acid content, this point puts them at especially high risk for oxidative damage. Besides its immunomodulatory effects, vitamin E also plays an important role in carcinogenesis with its antioxidant properties against cancer, and ischemic heart disease with limiting the progression of atherosclerosis. Supplementation of vitamin E significantly enhances both cell mediated and humoral immune functions in humans, especially in the elderly and animals.

Genetic studies reveal the role of the endocrine and metabolic systems in aging

Aging is a natural process that involves a general decline in many physiological functions, resulting in loss of function and eventually death. Extensive research is being performed in order to elucidate the biology of aging, especially with the advent of newer molecular and genetic methodologies. The endocrine system plays a major role in orchestrating cellular interactions, metabolism, growth, and senescence. Thus, researchers traditionally used hormones as tools to induce and examine specific biological effects that are associated with aging. Furthermore, because our recent knowledge on hormonal action expanded significantly, downstream pathways and genetic determinants currently prevail in aging research. In this review, we will summarize the effects of several hormones on human aging and longevity and present recent data from the Longevity Genes Study performed at Albert Einstein College of Medicine, looking at the phenotype and genotype of centenarians and their offspring. We will demonstrate that genetic factors that are associated with human longevity are heritable and may contribute not only to quantitative longevity but also to protection from age-dependent disease and exceptional good health.

Kaempferol suppresses cisplatin-induced apoptosis via inductions of heme oxygenase-1 and glutamate-cysteine ligase catalytic subunit in HEI-OC1 cell

PURPOSE

The present study was undertaken to elucidate the chemoprotective mechanism of kaempferol, which possesses anti-oxidative and anti-apoptotic properties.

METHODS

House Ear Institute-Organ of Corti 1 (HEI-OC1) cells were treated with kaempferol in the presence or absence of cisplatin. Cisplatin-induced oxidative stress was assessed by analysis of Comet assay, DNA-laddering assay and activation of caspases. Heme oxygenase-1 (HO-1), mitogen-activated protein kinase (MAPK) pathway and nuclear factor-E2-related factor 2 (Nrf2) were measured by Western blot analysis. Transfection of small interfering RNAs (siRNA), glutathione (GSH) assay and RT-PCR were performed in this study.

RESULTS

Kaempferol protected cells against cisplatin-induced apoptosis in a dose-dependent manner in HEI-OC1 cells. Kaempferol-induced HO-1 expression protected against cell death though the c-Jun N-terminal kinase (JNK) pathway and by the aid of Nrf2 translocation. Kaempferol increased the cellular level of GSH and the expression of GCLC time-dependently. siRNA GCLC blocked the increase of GSH level by kaempferol and the protective effect of kaempferol against cisplatin-induced cell death.

CONCLUSION

The expression of HO-1 by kaempferol inhibits cisplatin-induced apoptosis in HEI-OC1 cells, and the mechanism of protective effect is also associated with its inductive effect of GCLC expression.

Aging is not a process of wear and tear

The idea that bodies wear out with age is so ancient, so pervasive, and so deeply rooted that it affects our thought in unconscious ways. Undeniably, many aspects of aging, e.g., oxidative damage, somatic mutations, and protein cross-linkage are characterized by increased entropy in biomolecules. However, it has been a scientific consensus for more than a century that there is no physical necessity for such damage. Living systems are defined by their capacity to gather order from their environment, concentrate it, and shed entropy with their waste. Organisms in their growth phase become stronger and more robust; no physical law prohibits this progress from continuing indefinitely. Indeed, some animals and many plants are known to grow indefinitely larger and more fertile through their lives. The same conclusion is underscored by experimental findings that various insults and challenges that directly damage the body or increase the rate of wear and tear have the paradoxical effect of extending life span. Hyperactive mice live longer than controls, and worms with their antioxidant systems impaired live longer than wild type. A fundamental understanding of aging must proceed not from physics but from an evolutionary perspective: The body is being permitted to decay because systems of repair and regeneration that are perfectly adequate to build and rebuild a body of ever-increasing resilience are being held back. Regardless of the reason for this retreat, it should be more fruitful to focus on signaling to effect the ongoing activity of systems of repair and regeneration than to attempt repair of the manifold damage left in the wake of their failure.

A fluorimetric semi-microplate format assay of protein carbonyls in blood plasma

Oxidative stress, originating from reactive oxygen species (ROS), has been implicated in aging and various human diseases. The ROS generated can oxidize proteins producing protein carbonyl derivatives. The level of protein carbonyls in blood plasma has been used as a measure of overall oxidative stress in the body. Classically, protein carbonyls have been quantitated spectrophotometrically by directly reacting them with 2,4-dinitrophenylhydrazine (DNPH). However, the applicability of this method to biological samples is limited by its low inherent sensitivity. This limitation has been overcome by the development of sensitive enzyme-linked immunosorbent assay (ELISA) methods to measure protein carbonyls. As part of the Healthy Aging in Neighborhoods of Diversity across the Lifespan (HANDL) study, oxidative stress in humans was quantified by measuring blood plasma protein carbonyls using the two commercially available ELISA kits and the spectrophotometric DNPH assay. Surprisingly, two ELISA methods gave very different values for protein carbonyls, both of which were different from the value of the spectrophotometric method. We have developed a fluorescent semi-microplate format assay of protein carbonyls involving direct reaction of protein carbonyls with fluorescein thiosemicarbazide that correlates (R=0.992) with the direct spectrophotometric method. It has a coefficient of variation of 4.99% and is at least 100 times more sensitive than the spectrophotometric method.

The PPARgamma agonist pioglitazone ameliorates aging-related progressive renal injury

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists not only improve metabolic abnormalities of diabetes and consequent diabetic nephropathy, but they also protect against nondiabetic chronic kidney disease in experimental models. Here, we found that the PPAR-gamma agonist pioglitazone protected against renal injury in aging; it reduced proteinuria, improved GFR, decreased sclerosis, and alleviated cell senescence. Increased local expression of PPAR-gamma paralleled these changes. Underlying mechanisms included increased expression of klotho, decreased systemic and renal oxidative stress, and decreased mitochondrial injury. Pioglitazone also regulated p66(Shc) phosphorylation, which integrates many signaling pathways that affect mitochondrial function and longevity, by reducing protein kinase C-beta. These results suggest that PPAR-gamma agonists may benefit aging-related renal injury by improving mitochondrial function.

Plasma antioxidant capacity among middle‐aged men: The contribution of uric acid

OBJECTIVE

Although assays of plasma antioxidant capacity encompass interactions between various antioxidants, uric acid concentration can exert a predominant effect on results. Therefore, individual differences in uric acid concentration may explain a many of the differences in antioxidant capacity. The objective of this study was to measure the antioxidant capacity of plasma samples with and without uric acid in order to provide more information about how the concept of antioxidant capacity could be applied.

MATERIAL AND METHODS

Antioxidant capacity was measured using an enhanced chemiluminescence assay, and uric acid was removed from the samples using uricase.

RESULTS

Antioxidant capacity was positively correlated with uric acid concentration, body mass index, waist circumference, abdominal sagittal diameter and the concentrations of insulin and triglycerides. These correlations were not evident when uric acid was eliminated from the sample, but antioxidant capacity was correlated with lipid concentration; this may partly reflect tocopherols that are transported by lipid molecules.

CONCLUSIONS

The significance of the contribution of uric acid to the antioxidant capacity could differ according to the type of study. Antioxidant capacity measurements in cross-sectional studies may be presented both with and without the contribution of uric acid, because the absence of such data complicates interpretation of results when different populations are compared.

Glutathione dysregulation and the etiology and progression of human diseases

Glutathione (GSH) plays an important role in a multitude of cellular processes, including cell differentiation, proliferation, and apoptosis, and as a result, disturbances in GSH homeostasis are implicated in the etiology and/or progression of a number of human diseases, including cancer, diseases of aging, cystic fibrosis, and cardiovascular, inflammatory, immune, metabolic, and neurodegenerative diseases. Owing to the pleiotropic effects of GSH on cell functions, it has been quite difficult to define the role of GSH in the onset and/or the expression of human diseases, although significant progress is being made. GSH levels, turnover rates, and/or oxidation state can be compromised by inherited or acquired defects in the enzymes, transporters, signaling molecules, or transcription factors that are involved in its homeostasis, or from exposure to reactive chemicals or metabolic intermediates. GSH deficiency or a decrease in the GSH/glutathione disulfide ratio manifests itself largely through an increased susceptibility to oxidative stress, and the resulting damage is thought to be involved in diseases, such as cancer, Parkinson's disease, and Alzheimer's disease. In addition, imbalances in GSH levels affect immune system function, and are thought to play a role in the aging process. Just as low intracellular GSH levels decrease cellular antioxidant capacity, elevated GSH levels generally increase antioxidant capacity and resistance to oxidative stress, and this is observed in many cancer cells. The higher GSH levels in some tumor cells are also typically associated with higher levels of GSH-related enzymes and transporters. Although neither the mechanism nor the implications of these changes are well defined, the high GSH content makes cancer cells chemoresistant, which is a major factor that limits drug treatment. The present report highlights and integrates the growing connections between imbalances in GSH homeostasis and a multitude of human diseases.

Dual targeting of the antagonistic pathways mediated by Sirt1 and TXNIP as a putative approach to enhance the efficacy of anti-aging interventions

The organism's ability to regulate oxidative stress and metabolism is well recognized as a major determinant of longevity. While much research interest in this area is directed towards the study of genes that inhibit oxidative stress and/or improve metabolism, contribution to the aging process of genes with antagonistic effects on these two pathways is still less understood. The present study investigated the respective roles of the histone deacetylase Sirt1 and the thioredoxin binding protein TXNIP, two genes with opposite effects on oxidative stress and metabolism, in mediating the action of putative anti-aging interventions. Experiments were carried out in vitro and in vivo to determine the effect of proven, limited calorie availability, and unproven, resveratrol and dehydroepiandrosterone (DHEA), on the expression of Sirt1 and TXNIP. The results indicated that limited calorie availability consistently inhibited TXNIP in cancer and in normal cells including stem cells, however, it only slightly induced Sirt1expression in cancer cells. In contrast, resveratrol had a biphasic effect, and DHEA inhibited the expression of these two genes in a tissue specific manner, both in vitro and in vivo. Whereas all the three approaches tested inhibited TXNIP through the glycolytic pathway, DHEA acted by inhibiting G6PD and resveratrol through the activation of AMPK. In light of previous reports that Sirt1 induces AMPK-mediated signaling pathway, our findings point to the possibility of a negative relationship between Sirt1 and TXNIP that, if validated, can be exploited to improve the efficacy of putative anti-aging interventions.

Vitamin E ingestion improves several immune functions in elderly men and women

The effects of diet supplementation with the antioxidant vitamin E (200 mg daily) on several blood neutrophil, lymphocyte and natural killer cell functions have been investigated in healthy elderly men and women before supplementation, after 3 months of supplementation and 6 months after the end of supplementation (post-supplementation). In parallel, samples of healthy adult men and women were used as age controls. In elderly men and women, an impairment of immune functions was observed in comparison with the respective adult controls and the intake of vitamin E resulted in a significant enhancement of immune parameters in both elderly men and women, bringing their values close to those in the adults. These effects were not found in post-supplementation samples in several but not in all functions. The present findings suggest that supplementation with vitamin E can produce an improvement of immune functions and therefore of health in aged people.

Impact of post-thymic cellular longevity on the development of age-associated CD4+ T cell defects

Elderly people are at higher risk for infections due to declining cellular and humoral immune responses. Central to this dysfunction is the reduced responsiveness of the naive CD4(+) T cell compartment. Previous data from our laboratory suggest that although defects in the aged naive CD4(+) T cell response are apparent in recent thymic emigrant populations, additional defects develop during extended post-thymic longevity in the periphery. To further investigate the factors that lead to aging defects, we took advantage of the OT-II TCR-transgenic (Tg) mouse model. We show that because of an apparent superantigen-mediated loss of naive Vbeta5(+) Tg CD4(+) T cells from the periphery of aging OT-II mice, this compartment becomes enriched for cells of reduced post-thymic longevity, resulting in a frequency of recent thymic emigrants in aged mice that is similar to that of young mice. Purification and functional analysis of aged OT-II cells with reduced post-thymic longevity reveal that they have an age-associated decrease in expansion and IL-2 production in response to Ag in vitro. However, the in vivo expansion, IL-2 production, and cognate B cell helper ability of these cells are similar to those of cells from young mice. In contrast, T cells from aged HNT Tg mice demonstrate extended post-thymic longevity and exhibit severe defects in the same in vitro and in vivo models. These data support a correlation between the requirement for increased post-thymic longevity and the development of the most severe naive CD4(+) T cell-aging defects.

Evaluation of antioxidant deficit in schizophrenia

AIM

Oxidative stress is a state in which there is disequilibrium between pro-oxidant processes and the antioxidant defense system in favor of the former and occurs as a consequence of increased production of free radicals or when the antioxidant defense system is inefficient or a combination of both events. A disturbance in the antioxidant defense system, including antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSHPx), due to free radical-induced oxidative injury has also been implicated in various neuropsychiatric disorders. Hence the role of these antioxidant enzymes and the changes in their level in blood and correlation with oxidative stress and the overall mechanism of defense were studied in a common psychiatric illness, schizophrenia.

MATERIALS AND METHODS

Fifty subjects of either sex ranging in age from 18 to 60 years, divided into two age groups (< 40 years and >40 years), diagnosed for schizophrenia; and 50 age- and sex-matched normal subjects as controls were included in the study. Blood samples were collected for the determination of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSHPx), and reduced glutathione (GSH).

RESULTS

Significantly lower levels of the two antioxidant enzymes were found in schizophrenics compared to normal controls, with an increased oxidative stress as indicated by high blood MDA levels. The condition worsened with advancing age, smoking, among literate masses, and in chronic schizophrenics; whereas gender did not show any effect.

CONCLUSION

It can be concluded that an imbalance in the antioxidant defense system, along with enzymatic antioxidants, occurs in schizophrenia due to the persistent oxidative stress. Modern life style perhaps also contributes to the condition.

Superoxide radical-scavenging effects from polymorphonuclear leukocytes and toxicity in human cell lines of newly synthesized organic selenium compounds

Synthetic organic selenium compounds such as 2-phenyl-1,2-benzisoselenazol-3(2H)-one may show glutathione peroxidase-like antioxidant activity. Recently, we synthesized new organic selenium compounds that are thought to be effective antioxidants. To study their possible applications as antioxidants, we evaluated two selenoureas, N,N-dimethylselenourea and 1-selenocarbamoylpyrrolidine, and two tertiary selenoamides, N-(phenylselenocarbonyl)-piperidine and N,N-diethyl-4-chloroselenobenzamide, for their superoxide radical (O2-)-scavenging effects and toxicity. We measured (O2-)-scavenging effects in polymorphonuclear leukocytes (PMNs) with a specific, sensitive and real-time kinetic chemiluminescence method. Furthermore, the toxicity of these compounds was measured in some human cell lines and PMNs using the tetrazolium method. Hydrogen peroxide was measured by a scopoletin method. Finally, translocation of an NADPH oxidase component, p47 phagocyte oxidase, to the cell membrane was investigated by confocal laser scanning microscopy. N,N-Dimethylselenourea and 1-selenocarbamoylpyrrolidine effectively scavenged (O2-) released from 4beta-phorbol 12-myristate 13-acetate-stimulated PMNs, and the 50% inhibitory concentrations were 6.8 +/- 2.2 and 6.5 +/- 2.5 microm, respectively. N-(Phenylselenocarbonyl)-piperidine and N,N-diethyl-4-chloroselenobenzamide also effectively scavenged (O2-) from PMNs, and the 50% inhibitory concentrations were 11.3 +/- 4.8 and 20.3 +/- 6.4 microm, respectively. Selenoureas showed very low toxicity in human cell lines and PMNs, even at high concentrations, whereas tertiary selenoamides were cytotoxic. These compounds did not produce significant amounts of hydrogen peroxide from 4beta-phorbol 12-myristate 13-acetate-stimulated PMNs. None of the compounds significantly affected the translocation of p47 phagocyte oxidase. Selenoureas acted as effective antioxidants and showed low toxicity in some human cells. Thus, these compounds might be new candidates as antioxidative substances.