Aging: phenomena and theories

Altered transcriptomic and metabolomic profiles of testicular interstitial fluid during aging in mice

The testicular interstitial fluid (TIF) that bathes seminiferous tubules and testicular interstitial cells is the main microenvironment of the testis and involved in crosstalk between testicular cells. TIF also provides a new mean to investigate dysfunctional states of testis such as spermatogenic disorder and aging. In this study, we performed integrative omics analysis on the exosomal transcriptomics and liquid chromatography-tandem mass spectrometry (LC-MS/MS) based non-targeted metabolomics in TIF by comparison between 21-month-old and 3-month-old male mice. A total of 1627 genes were identified as aging-related differently expressed genes (DEGs) in mouse TIF exosomes, with 1139 downregulated and 488 upregulated. Functional and pathway analysis revealed that the DEGs were associated with oxidative stress, carbon metabolism, and systemic lupus erythematosus. By comparing the DEGs with the Aging Atlas Database, we screened out key aging-related genes functioning as oxidative stress regulators, and their expression pattern in human testis with age was confirmed by immunohistochemistry results in the Human Protein Atlas database. In addition, the metabolomic analysis identified mild differences between young and old groups with 28 downregulated differently expressed metabolites (DEMs) and 6 upregulated DEMs, in the negative ion mode, including decreased level of several antioxidant metabolites. The KEGG analysis demonstrated that 10 pathways were upregulated, while the pyrimidine metabolism pathway was downregulated in the aged mice TIF. Taken together, this study highlighted the prominent role of oxidative stress that contributed to the aging microenvironment in the TIF, and brought comprehensive transcriptomic and metabolomic perspectives for understanding the mechanism underlying the testicular aging.

Oxidative stress, aging, antioxidant supplementation and their impact on human health: An overview

Aging is characterized by a progressive loss of tissue and organ function due to genetic and environmental factors, nutrition, and lifestyle. Oxidative stress is one the most important mechanisms of cellular senescence and increased frailty, resulting in several age-linked, noncommunicable diseases. Contributing events include genomic instability, telomere shortening, epigenetic mechanisms, reduced proteome homeostasis, altered stem-cell function, defective intercellular communication, progressive deregulation of nutrient sensing, mitochondrial dysfunction, and metabolic unbalance. These complex events and their interplay can be modulated by dietary habits and the ageing process, acting as potential measures of primary and secondary prevention. Promising nutritional approaches include the Mediterranean diet, the intake of dietary antioxidants, and the restriction of caloric intake. A comprehensive understanding of the ageing processes should promote new biomarkers of risk or diagnosis, but also beneficial treatments oriented to increase lifespan.

Functions of somatic cells for spermatogenesis in stallions

Spermatogenesis and testis development are highly structured physiological processes responsible for post-pubertal fertility in stallions. Spermatogenesis comprises spermatocytogenesis, meiosis, and spermiogenesis. Although germ cell degeneration is a continuous process, its effects are more pronounced during spermatocytogenesis and meiosis. The productivity and efficiency of spermatogenesis are directly linked to pubertal development, degenerated germ cell populations, aging, nutrition, and season of the year in stallions. The multiplex interplay of germ cells with somatic cells, endocrine and paracrine factors, growth factors, and signaling molecules contributes to the regulation of spermatogenesis. A cell-to-cell communication within the testes of these factors is a fundamental requirement of normal spermatogenesis. A noteworthy development has been made recently on discovering the effects of different somatic cells including Leydig, Sertoli, and peritubular myoid cells on manipulation the fate of spermatogonial stem cells. In this review, we discuss the self-renewal, differentiation, and apoptotic roles of somatic cells and the relationship between somatic and germ cells during normal spermatogenesis. We also summarize the roles of different growth factors, their paracrine/endocrine/autocrine pathways, and the different cytokines associated with spermatogenesis. Furthermore, we highlight important matters for further studies on the regulation of spermatogenesis. This review presents an insight into the mechanism of spermatogenesis, and helpful in developing better understanding of the functions of somatic cells, particularly in stallions and would offer new research goals for developing curative techniques to address infertility/subfertility in stallions.

Comparison in Content of Total Polyphenol, Flavonoid, and Antioxidant Capacity from Different Organs and Extruded Condition of Moringa oleifera Lam

Recently, interest in exploring phytochemicals with health benefits has grown significantly. In this research, we aimed to develop the processing profile and functionality of Moringa oleifera Lam. Here, we implemented biopolymer-mediated extrudate formulations of M. oleifera (leaves, seed, and husk) in order to enhance the phenolic, flavonoid, and antioxidant capacity. The formulation-1 (F1) was prepared for leaves, seed, and husk using biopolymers (10% w/w), namely: whey protein isolate (10% w/w) and lecithin (5% w/w) with vitamin E (2% w/w). The formulation-2 (F2) was composed of lecithin (5% w/w) with ascorbyl palmitate (10% w/w) and vitamin E (2% w/w), processed by hot-melt extrusion (HME). It was observed that the total phenol and flavonoid contents were persistent in the lecithin-mediated F2 formulation of leaves, seed, and husk. Likewise, antioxidant capacity was significantly stayed in the F2 formulation of all organs, compared to the extrudate and control. The IC50 values revealed that the leaves of the F2 formulation showed strong free radical scavenging capacity compared to the F2 formulation of seed and husk. It was concluded that the F2 formulation could be used in the different parts of M. oleifera processing to boost functionality.

Physical Health and Work Ability among Healthcare Workers. A Cross-Sectional Study

Healthcare workers’ age is increasingly rising, negatively affecting their physical health. In particular, workability is an emerging phenomenon that predominantly affects healthcare workers. This study aims to assess physical health status and workability among ageing healthcare workers. A cross-sectional study using the Work Ability Index (WAI) was performed. Data were collected in a university hospital in northern Italy. Data were collected voluntary through a questionnaire. Healthcare workers participating in the survey were contacted personally by two resident physicians. Thus, the total number of study participants was 220 among nursing aides, nurses, and physicians. Data were analyzed by performing ANOVA and regression to assess the differences between the healthcare workers and age groups. A generalized linear model was tested to evaluate the effect of age and task on workability. The majority of healthcare workers had good WAI values. Physicians’ workability was higher than nursing aides. Nursing aides suffered more from cardiovascular disorders, while physicians and nurses had more musculoskeletal disorders. However, the distribution was statistically different (χ² = 24.03, p = 0.00), as most of the physicians’ workability values were good and good, while those of nursing aides and nurses were good and medium. In line with previous studies, the decrease in WAI with ageing is strictly dependent on the type of task assigned. Due to heavy physical tasks, nurses and nurses’ aides showed a greater WAI than physicians. This study highlights the critical issues faced by ageing healthcare professionals. In the near future, it is necessary to find solutions to cope with these changes and devise possible interventions aimed at ameliorating workability.

Effect of Li-ESWT on Testicular Tissue and Function in Androgen-Deficient Rat Model

Low-intensity extracorporeal shockwave therapy (Li-ESWT), as a microenergy therapy, has the effects of inhibiting oxidative stress, antiapoptosis, and tissue repair, which is increasingly applied to a variety of diseases. Our research aims to explore the protective effects of Li-ESWT in the aging rat model and its possible molecular mechanism through in vivo and in vitro experiments. In vitro, TM3 Leydig cells incubated with H₂O₂ were treated with Li-ESWT at 4 energy levels (0.01, 0.05, 0.1, and 0.2 mJ/mm²). In vivo, we employed an androgen-deficient rat model to simulate male aging and treated it with Li-ESWT at three different energy levels (0.01, 0.05, and 0.2 mJ/mm²). Li-ESWT increased the expression of vascular endothelial growth factor (VEGF) in TM3 cells, improved antioxidant capacity, and reduced apoptosis, with the effect being most significant at 0.05 mJ/mm² energy level. In androgen-deficient rat model, LI-ESWT can improve sperm count, motility, and serum testosterone level, enhancing tissue antioxidant capacity and antiapoptotic ability, and the effect is most significant at 0.05 mJ/mm² energy level. Therefore, Li-ESWT at an appropriate energy level can improve sperm count, motility, and serum testosterone levels in androgen-deficient rat models, reduce oxidative stress in the testis, and increase antioxidant capacity and antiapoptotic abilities. The mechanism of this condition might be related to the increased VEGF expression in Leydig cells by Li-ESWT.

Kenaf (Hibiscus cannabinus L.) Leaves and Seed as a Potential Source of the Bioactive Compounds: Effects of Various Extraction Solvents on Biological Properties

Hibiscus cannabinus (Kenaf) is a potential source of bioactive constituents and natural antioxidant. The current study determined the impact of various solvents on extraction yield, recovery of polyphenol and flavonoid, antioxidant, anticancer, and antibacterial properties of Kenaf leaves and seed. The powder of leaves and seed was separately extracted with n-hexane, ethyl acetate, ethanol, and water solvent. Among them, the ethanol extract of leaves and seed showed the highest extraction yield, and their GC-MS analysis revealed a total of 55 and 14 bioactive compounds, respectively. The total polyphenols (TP) and flavonoids (TF) content were quantified by a spectrophotometric technique where water extracts displayed a noteworthy amount of TP and TF content compared to other extracts. A similar demonstration was noticed in antioxidant activity, evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) and hydrogen peroxide scavenging capacity. In addition, cytotoxicity and anti-lung cancer activity were identified against mouse embryonic fibroblast (NIH3T3) and human lung cancer (A549) cells. All extracts of leaves and seed were observed as non-toxic to the NIH3T3 cells, but slight toxicity was expressed by n-hexane extracts at the optimum dose (1000 µg/mL) of treatment. In parallel, n-hexane and ethanol extracts (leaves and seed) exposed promising anti-lung cancer activity at the same concentration. Furthermore, antibacterial activity was assessed using disc diffusion assay, and seed extracts exhibited a significant inhibition zone against Gram-positive and Gram-negative microorganisms. Overall, Kenaf seed extracted with polar solvents was found very potent in terms of important bioactive compounds and pharmacological aspects, which can be an excellent biological matrix of natural antioxidants.

Lack of retinoid acid receptor-related orphan receptor alpha accelerates and melatonin supplementation prevents testicular aging

The role of retinoid acid receptor-related orphan receptor alpha (RORα) on male reproductive functions during aging is unclear. Here, we analyze the morphological changes in the testis of both young and aged RORα-deficient mice, with and without melatonin supplementation. Young mutants showed vacuolation, degeneration and pyknosis of spermatogenic epithelium and Sertoli cells. Aged mutants showed atrophy of the seminiferous tubules and absence of mitotic spermatogenic cells. Absence of sperms in many tubules, loss of acrosomal cap, vacuolation and hypertrophy of Sertoli cells were detected in aged mice, with a significant reduction in the number of seminiferous tubules and a significant increase in the number of Leydig cells and telocytes. Repair in seminiferous tubules and interstitial tissues with enhancement of spermatogenesis was observed in melatonin-treated aged mice. Young mutants overexpressed VEGF that was weaker in aged animals and observed only in the spermatocytes, while melatonin increased VEGF expression in spermatocytes and spermatids. Caspase 3 increased in both young and aged mutant mice in all seminiferous tubules and interstitium; caspase 3 immunostaining in seminiferous tubules, however, showed a normal pattern of apoptosis with melatonin supplementation. The present study reports that age-dependent testicular changes in RORα mutant mice were recovered by melatonin treatment.

Ageing in human parturition: impetus of the gestation clock in the decidua†

Despite sharing many common features, the relationship between ageing and parturition remains poorly understood. The decidua is a specialized lining of endometrial tissue, which develops in preparation for pregnancy. The structure and location of the decidua support its role as the physical scaffold for the growing embryo and placenta, and thus, it is vital to sustain pregnancy. Approaching term, the physical support properties of the decidua are naturally weakened to permit parturition. In this review, we hypothesize that the natural weakening of decidual tissue at parturition is promoted by the ageing process. Studies of the ageing-related functional and molecular changes in the decidua at parturition are reviewed and classified using hallmarks of ageing as the framework. The potential roles of decidual mesenchymal stem/stromal cell (DMSC) ageing in labor are also discussed because, although stem cell exhaustion is also a hallmark of ageing, its role in labor is not completely understood. In addition, the potential roles of extracellular vesicles secreted by DMSCs in labor, and their parturition-related miRNAs, are reviewed to gain further insight into this research area. In summary, the literature supports the notion that the decidua ages as the pregnancy progresses, and this may facilitate parturition, suggesting that ageing is the probable impetus of the gestational clocks in the decidua. This conceptual framework was developed to provide a better understanding of the natural ageing process of the decidua during parturition as well as to encourage future studies of the importance of healthy ageing for optimal pregnancy outcomes.

Lizard Tail Extracts Exert Protective Effect Against Oxidative Stress-Induced Cellular Senescence in Human Fibroblasts

Lizards are the evolutionarily closest animals to humans among the self-renewable species. Recent reports show that lizard tail extracts (LTE) inhibit the proliferation and angiogenesis of cancer cells but do not show any toxicity against human fibroblast cells. Nevertheless, few scientific studies investigated the effects of LTE on the treatment of skin diseases, especially oxidative stress aging. Therefore, we explored the effect of LTE on the anti-aging activity of human fibroblasts. We confirmed the anti-aging effect of LTE by SA-β-galactosidase staining. In addition, the hydrogen peroxide-induced reactive oxygen species (ROS) were decreased by the LTE, as measured by staining with the 2',7'-dichlorofluorescein diacetate reagent. We performed Western blot analysis to examine the signaling pathways. In conclusion, the LTE can prevent cellular senescence through the suppression of ROS and the downregulation of p21.

Chemiluminescence quenching microarrays for high throughput screening of antioxidants and its application in evaluating herbal extracts and pure compounds

In this paper, a novel high throughput screening method for antioxidants was described. The screening process was completed on a 5 cm × 5 cm silica gel 60 plate. Luminol was used as the fluorogenic substrate while hydrogen peroxide employed to excite the chemiluminescence. A dark spot was observed due to quenching effect of antioxidant. A linear model of the integral area of the spot as a function of analyte amount was fit by using vitamin C as positive control. Excellent linearity (R² = 0.9978) was obtained in the range of 2.31-23.1 μg. The variation coefficients of intra- and inter-chip precisions were below 5% (n = 10) and 10% (n = 6) respectively. The new method was validated by comparing the analysis result of six flavonoids with that from a sequential injection method. The Pearson correlation coefficient was up to 0.98. A set of traditionally used herbal medicines was screened, and Rhei Radix et Rhizoma showed the strongest signal. The major bioactive ingredients were further assigned by flow injection and MS analyses. These results reveal the prospects of the proposed method to supply a promising tool in vitro for high throughput screening and activity evaluation of antioxidants in a fast, low-cost and reliable manner.

Degradation of Caytaxin Causes Learning and Memory Deficits via Activation of DAPK1 in Aging

Loss of memory is an inevitable clinic sign in aging, but its underlying mechanisms remain unclear. Here we show that death-associated protein kinase (DAPK1) is involved in the decays of learning and memory in aging via degradation of Caytaxin, a brain-specific member of BNIP-2. DAPK1 becomes activated in the hippocampus of mice during aging. Activation of DAPK1 is closely associated with degradation of Caytaxin protein. Silencing Caytaxin by the expression of small interfering RNA (siRNA) that targets specifically to Caytaxin in the hippocampus of adult mice impairs the learning and memory. Genetic inactivation of DAPK1 by deletion of DAPK1 kinase domain prevents the degradation of Caytaxin and protects against learning and memory declines. Thus, activation of DAPK1 impairs learning and memory by degrading Caytaxin during aging.

Peroxisomes: role in cellular ageing and age related disorders

Peroxisomes are dynamic organelles essential for optimum functioning of a eukaryotic cell. Biogenesis of these organelles and the diverse functions performed by them have been extensively studied in the past decade. Their ability to perform functions depending on the cell type and growth conditions is unique and remarkable. Oxidation of fatty acids and reactive oxygen species metabolism are the two most important functions of these ubiquitous organelles. They are often referred to as both source and sink of reactive oxygen species in a cell. Recent research connects peroxisome dysfunction to fatal oxidative damage associated with ageing-related diseases/disorders. It is now widely accepted that mitochondria and peroxisomes are required to maintain oxidative balance in a cell. However, our understanding on the inter-dependence of these organelles to maintain cellular homeostasis of reactive oxygen species is still in its infancy. Herein, we summarize findings that highlight the role of peroxisomes in cellular reactive oxygen species metabolism, ageing and age-related disorders.

Age related distribution of 4-hydroxy 2-nonenal immunoreactivity in human retina

The retina is prone to be damaged by oxidative stress (OS), owing to its constant exposure to light, high rate of oxygen consumption and high membrane lipid content. Lipid peroxidation in aging human retina has been shown by biochemical means. However, information on the cellular sites of OS and antioxidant responses in aging human retina remains limited. Here, we show distribution of immunoreactivity (IR) to a marker of lipid peroxidation (4-hydroxy 2-nonenal [HNE] and antioxidant enzymes involved in counteracting lipid peroxidation (glutathione S-transferase-π1 and glutarexoxin-1) in donor human retinas at different ages (35-91 years; N = 24). Initially, HNE-IR was present in few macular cone outer segments (COS, sixth decade). With aging, IR appeared in many COS and peaked at ninth decade (14 vs 62 per 3850 μm² area between 6 and 9 decade; p < 0.001) in the parafovea then seen elsewhere (perifoveal, mid-peripheral and nasal). IR was seen in the parafovea of all retinas, whereas it was present in 8/24 of perifoveal and 6/24 of mid-peripheral retinas, indicating that the parafovea is susceptible to undergo lipid peroxidation. Foveolar COS were immunonegative until 81 years, which developed IR later (>83 years). IR to glutathione S-transferase-π1 was moderate until eight decade and then showed a decrease in photoreceptor cells between ninth and tenth decade, while glutaredoxin-1 maintained a steady expression with aging. Damaged COS were present in aged retinas, and inner segments and photoreceptor nuclei also showed some degree of alterations. Although there was increased lipid peroxidation with aging, cone death was minimal in those retinas. The two antioxidant enzymes studied here, may play a role in protecting photoreceptors against OS with advanced aging.

Terrein reduces age-related inflammation induced by oxidative stress through Nrf2/ERK1/2/HO-1 signalling in aged HDF cells

This study investigated whether multiple bioactivity of terrein such as anti-inflammatory and anti-oxidant inhibits age-related inflammation by promoting an antioxidant response in aged human diploid fibroblast (HDF) cells. HDF cells were cultured serially for in vitro replicative senescence. To create the ageing cell phenotype, intermediate stage (PD31) HDF cells were brought to stress-induced premature senescence (SIPS) using hydrogen peroxide (H2 O2). Terrein increased cell viability even with H2O2 stress and reduced inflammatory molecules such as intracellular adhesion molecule-1 (ICAM-1), cyclooxygenase-2 (COX-2), interleukin-1beta (IL-1β) and tumour necrosis factor-alpha (TNF-α). Terrein reduced also phospho-extracellular kinase receptor1/2 (p-EKR1/2) signalling in aged HDF cells. SIPS cells were attenuated for age-related biological markers including reactive oxygen species (ROS), senescence associated beta-galactosidase (SA β-gal.) and the aforementioned inflammatory molecules. Terrein induced the induction of anti-oxidant molecules, copper/zinc-superoxide defence (Cu/ZnSOD), manganese superoxide dismutase (MnSOD) and heme oxygenase-1 (HO-1) in SIPS cells. Terrein also alleviated reactive oxygen species formation through the Nrf2/HO-1/p-ERK1/2 pathway in aged cells. The results indicate that terrein has an alleviative function of age-related inflammation characterized as an anti-oxidant. Terrein might be a useful nutraceutical compound for anti-ageing.

Oxidative stress and the unfulfilled promises of antioxidant agents

It is well known that aging and its associated diseases, including cancer, are triggered by oxidative damage to biological macromolecules. However, antioxidant compounds are still disappointingly distant from any clinical application, so that Jim Watson has declared that antioxidant supplementation may have caused more cancers than it has prevented Watson J ((2013) Oxidants, antioxidants and the current incurability of metastatic cancers Open Biol 3 DOI: 10.1098/rsob.120144). To clarify this paradox, here, we describe the mechanisms of oxidative stress focusing in particular on redox balance and physiological oxidative signals.

Cytoskeleton involvement in lithium-induced SH-SY5Y neuritogenesis and the role of glycogen synthase kinase 3β

Lithium modulates signals impacting on the cytoskeleton, a dynamic system contributing to neural plasticity at multiple levels. In this study, SH-SY5Y human neuronal cells were cultured in the absence (C) or in presence (Li) of a 0.5 mM Li2CO3 (i.e. 1 mM lithium ion) for 25-50 weeks. We investigated the effect of this treatment on (1) morphological changes of cells observed using Hemalun eosin staining assay, (2) cytoskeletal changes by indirect immunofluorescence (IIF) staining of microtubules (α-tubulin) and heavy neurofilaments subunits (NF-H) and by measuring the expression rate changes of genes coding for receptor for activated C kinase (RACK1), casein kinase2 (CK2) and thymosine beta-10 using cDNA arrays technology, (3) cell adhesion properties by IIF staining of β-catenin protein. Besides, we have tried to understand the molecular mechanism of lithium action that triggers changes in cytoskeleton and neurites outgrowth. Thus, we examined the effect of this treatment on glycogen synthase kinase 3 (GSK3) expression and activity using western blotting of GSK3 and phosphorylated β-catenin, a downstream GSK3 target protein. Our results showed that lithium treatment reduces axon length, increases axonal spreading, enhances neurites growth and neurites branching with an increase of growth cone size. Moreover, genes coding for CK2 and thymosine beta-10 were significantly up-regulated, however, that coding for RACK1 was down-regulated. The most interesting result in this work is that mechanism underlying lithium action was not related to the inhibition of GSK3 activity. In fact, neither expression rate nor activity of this protein was changed.

Antioxidant capacity and radical scavenging effect of polyphenol rich Mallotus philippenensis fruit extract on human erythrocytes: an in vitro study

Mallotus philippinensis is an important source of molecules with strong antioxidant activity widely used medicinal plant. Previous studies have highlighted their anticestodal, antibacterial, wound healing activities, and so forth. So, present investigation was designed to evaluate the total antioxidant activity and radical scavenging effect of 50% ethanol fruit glandular hair extract (MPE) and its role on Human Erythrocytes. MPE was tested for phytochemical test followed by its HPLC analysis. Standard antioxidant assays like DPPH, ABTS, hydroxyl, superoxide radical, nitric oxide, and lipid peroxidation assay were determined along with total phenolic and flavonoids content. Results showed that MPE contains the presence of various phytochemicals, with high total phenolic and flavonoid content. HPLC analysis showed the presence of rottlerin, a polyphenolic compound in a very rich quantity. MPE exhibits significant strong scavenging activity on DPPH and ABTS assay. Reducing power showed dose dependent increase in concentration absorption compared to standard, Quercetin. Superoxide, hydroxyl radical, lipid peroxidation, nitric oxide assay showed a comparable scavenging activity compared to its standard. Our finding further provides evidence that Mallotus fruit extract is a potential natural source of antioxidants which have a protective role on human Erythrocytes exhibiting minimum hemolytic activity and this justified its uses in folklore medicines.

In vitro antioxidant potential of dicliptera roxburghiana

Background

Stress caused by free radicals accumulation result into many hazardous diseases. A number of investigations are focusing to find out the plant oriented natural antioxidant moieties. The basic aim of this research was to investigate the antioxidant potential, total Phenolic and flavonoids contents and photochemical screening of the crude methanol extract and its derived various fractions Dicliptera roxburghiana of Acanthaceae family.

Methods

Crude methanol extract of aerial parts of Dicliptera roxburghiana (DRME) was partitioned in to n-hexane (DRHF), chloroform (DRCF), ethyl acetate (DREF), n-butanol (DRBF) and the remaining soluble portion as residual aqueous fraction (DRAF). We evaluated the antioxidant activities of the extract and various fractions through different analytical methods such as DPPH, superoxide anion, ABTS, H₂O₂, hydroxyl radical and phosphomolybdate radical inhibition. In vitro lipid peroxidation and reducing power of the plant was also analyzed. Total flavonoid and phenolic contents of the extract and all fractions were also quantified. Plant was also subjected for preliminary phytochemical screening to confirm the presence or absence of various constituents in the plant.

Results

Phytochemical screening confirmed the presence of flavonoids, phenolics, tannins, alkaloids, saponins, terpenoids and coumarines. Quantitative analysis revealed the maximum amount of total phenolic and flavonoid contents in DRME while lowest in DRHF. Methanol extract, DREF, DRCF and DRBF exhibited promising antioxidant potential for DPPH, ABTS, H₂O₂, phosphomolybdate, superoxide anion and hydroxyl radical scavenging capabilities, while these were not appreciable for DRHF and DRAF. All fractions except DRHF and DRAF possess strong reducing power ability and showed appreciable lipid peroxidation inhibition.

Conclusion

These research investigations revealed that Dicliptera roxburghiana is a potent source of natural antioxidants. Hence the plant can be used for management of different stress and anxiety related ailments.

Zingipain, a ginger protease with acetylcholinesterase inhibitory activity

In order to search for new acetylcholinesterase inhibitors (AChEIs), 15 Zingiberaceae plants were tested for AChEI activity in rhizome extracts. The crude homogenate and ammonium sulfate cut fraction of Zingiber officinale contained a significant AChEI activity. Eighty percent saturation ammonium sulfate precipitation and diethylaminoethyl cellulose ion exchange chromatography (unbound fraction) enriched the protein to a single band on nondenaturing and reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (approximately 33.5 kDa). Gelatin-degrading zymography showed that the AChEI-containing band also contained cysteine protease activity. The AChEI activity was largely stable between -20 and 60 °C (at least over 120 min) and over a broad pH range (2-12). The AChEI activity was stimulated strongly by Mn(2+) and Cu(2+) at 1-10 mM and weakly by Ca(2+), Fe(2+), Mg(2+), and Zn(2+) at 1 mM, but was inhibited at 10 mM. In contrast, Hg(2+) and ethylenediaminetetraacetic acid were very and moderately strongly inhibitory, respectively. In-gel tryptic digestion with liquid chromatography-tandem mass spectroscopy resolution revealed two heterogeneous peptides, a 16-amino-acid-long fragment with 100 % similarity to zingipain-1, which is a cysteine protease from Z. officinale, and a 9-amino-acid-long fragment that was 100 % identical to actinidin Act 2a, suggesting that the preparation was heterogeneous. AChEI exhibited noncompetitive inhibition of AChE for the hydrolysis of acetylthiocholine iodide with a K(i) value of 9.31 mg/ml.

Age-related changes in nitric oxide activity, cyclic GMP, and TBARS levels in platelets and erythrocytes reflect the oxidative status in central nervous system

Aging is associated with an increased susceptibility to neurodegenerative disorders which has been linked to chronic inflammation. This process generates oxygen-reactive species, ultimately responsible for a process known as oxidative stress, leading to changes in nitric oxide (NO), and cyclic guanosine monophosphate (cyclic GMP) signaling pathway. In previous studies, we showed that human aging was associated with an increase in NO Synthase (NOS) activity, a decrease in basal cyclic GMP levels in human platelets, and an increase in thiobarbituric acid-reactant substances (TBARS) in erythrocytes. The aim of the present work was to evaluate NOS activity, TBARS and cyclic GMP levels in hippocampus and frontal cortex and its correlation to platelets and erythrocytes of 4-, 12-, and 24-month-old rats. The result showed an age-related decrease in cyclic GMP levels which was linked to an increase in NOS activity and TBARS in both central areas as well as in platelets and erythrocytes of rats. The present data confirmed our previous studies performed in human platelets and erythrocytes and validate NOS activity and cyclic GMP in human platelet as well as TBARS in erythrocytes as biomarkers to study age-related disorders and new anti-aging therapies.

Transthyretin aggregates induce production of reactive nitrogen species

BACKGROUND AND OBJECTIVE

Misfolded and aggregated transthyretins (agTTR) contribute to neurodegenerative amyloid diseases such as familial amyloid polyneuropathy and senile systemic amyloidosis. The neurotoxicity mechanisms of agTTR, however, are not well understood. In the current study, the possible contribution of reactive nitrogen species (RNS) to such mechanisms was investigated by examining agTTR-mediated changes in cellular RNS levels.

METHODS AND RESULTS

The production of RNS was assessed through nitrate and nitrite assays in two human cell lines after exposure to agTTR (2.4 µM pre-aggregation concentration). In both epidermoid (A431) and schwannoma (sNF94.3) cell lines, agTTR induced significant increases in RNS (p < 0.05 relative to the same concentration of normal TTR, or no-TTR controls). Redox modulators such as apocynin (1-(4-hydroxy-3-methoxy-phenyl)ethanone) and L-NMMA (N(G)-monomethyl-L-arginine) were tested for their effects on RNS production. These modulators decreased RNS production in both cell lines; although the effects of L-NMMA were statistically significant only in the schwannoma cells. Moreover, cells treated with agTTR exhibited decreases in metabolic activity relative to TTR- or non-TTR-treated cells (p < 0.05) as assessed by reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide).

CONCLUSION

The results provide novel evidence for involvement of RNS in pro-oxidative effects of agTTR in two different human cell lines, and show that agTTR can induce more generalized changes in cellular metabolic activity.

Are Bombax buonopozense and Bombax malabaricum possible nutraceuticals for age management?

Human longevity and healthy ageing though controversial require extended investigations. Some studies have shown that ageing can be managed by reducing the amounts of free radicals the cells are exposed to. Oxidative stress has been shown to be combated by antioxidants and plant sources are known to generate antioxidants that are efficacious and low in toxicity. This review aims to enlighten on antioxidants from Bombax buonopozense and Bombax malabaricum for prevention, reversal or delay of age-related diseases. Furthermore, it advocates for more studies to enable the shift from research to commercial applications of the antioxidants as nutraceuticals in age management.

Antioxidant and neuroprotective properties of blueberry polyphenols: a critical review

OBJECTIVE

The aim of this work was to highlight the effects and the possible mechanisms of the action of blueberry polyphenols on the central nervous system (CNS).

METHODS

An analysis was carried out, in a temporal order, of the most important literature about this topic and the results have been correlated with the beneficial and protective effects, mainly concerning the CNS.

DISCUSSION

Over the last 10 years an increasing scientific interest has developed about polyphenols, which are very abundant in blueberries, as they have been seen to produce favourable effects related to neuroprotection and linked to a possible decrease of age-related cognitive and motor decline, as shown by the improvement of such functions in animal models with a supplemented diet. Such effects could not only be explained through a purely antioxidant action but also through more complex mechanisms related to inflammation, genic expression, and regulation of cell survival.

CONCLUSIONS

Despite the wealth of data from animal studies, there is a relative lack of data concerning human beings, even if some positive results are beginning to emerge. Therefore, blueberry polyphenols could become useful pharmacological agents for various conditions including neurological diseases, but further studies are still necessary to attain this objective.

Modulation of collagen synthesis and its gene expression in human skin fibroblasts by tocotrienol-rich fraction

INTRODUCTION

Skin aging may occur as a result of increased free radicals in the body. Vitamin E, the major chain-breaking antioxidant, prevents propagation of oxidative stress, especially in biological membranes. In this study, the molecular mechanism of tocotrienol-rich fraction (TRF) in preventing oxidative stress-induced skin aging was evaluated by determining the rate of total collagen synthesis and its gene expression in human skin fibroblasts.

MATERIAL AND METHODS

Primary culture of human skin fibroblasts was derived from circumcision foreskin of 9 to 12 year-old boys. Fibroblast cells were divided into 5 different treatment groups: untreated control, hydrogen peroxide (H(2)O(2))-induced oxidative stress (20 µM H(2)O(2) exposure for 2 weeks), TRF treatment, and pre- and post-treatment of TRF to H(2)O(2)-induced oxidative stress.

RESULTS

Our results showed that H(2)O(2)-induced oxidative stress decreased the rate of total collagen synthesis and down-regulated COL I and COL III in skin fibroblasts. Pre-treatment of TRF protected against H(2)O(2)-induced oxidative stress as shown by increase in total collagen synthesis and up-regulation of COL I and COL III (p<0.05) genes. However, similar protective effects against H(2)O(2)-induced oxidative stress were not observed in the post-treated fibroblasts.

CONCLUSIONS

Tocotrienol-rich fraction protects against H(2)O(2)-induced oxidative stress in human skin fibroblast culture by modulating the expression of COL I and COL III genes with concomitant increase in the rate of total collagen synthesis. These findings may indicate TRF protection against oxidative stress-induced skin aging.

The butanol fraction of Eclipta prostrata (Linn) increases the formation of brain acetylcholine and decreases oxidative stress in the brain and serum of cesarean-derived rats

Eclipta prostrata has been used as a traditional medicinal plant to prevent dementia and to enhance memory in Asia. Its potential as a nootropic and as an antioxidant have been reported in mice. We hypothesized that Eclipta may affect the formation of neurotransmitters and the inhibition of oxidative stress. Charles River cesarean-derived rats (male, 180 ± 10 g) were fed experimental diets supplemented with 0 mg (control), 25 mg (E25), 50 mg (E50), or 100 mg (E100) of a freeze-dried butanol fraction of E prostrata per kilogram of diet for 6 weeks. The acetylcholine level was significantly increased by 9.6% and 12.1% in the brains of E50 and E100 groups, respectively, as compared with the control group that was fed standard diet alone. The acetylcholine esterase activity was significantly increased by 13.1% and 19.7% in the brains of E50 and E100 groups, respectively, compared with the control group. Monoamine oxidase-B activity was significantly decreased by 10.5% in the brains of the E100 group, and the superoxide radical level was significantly reduced by 9.4% in the serum of the E100 group compared with the control group. Superoxide dismutase activity was significantly increased by 9.6% and 11.6% in the serum of E50 and E100 groups, respectively, compared with the control group. These results clearly demonstrate the effects of E prostrata on the formation of acetylcholine in the brain and the inhibition of oxidative stress in the brain and serum of rats. These findings may have implications for preventing dementia and enhancing memory function in humans.

Age-related association of rDNA and telomeres with the nuclear matrix in mouse hepatocytes

Transcribed sequences have been suggested to be associated with the nuclear matrix, differing from non-transcribing sequences, which have been reported to be contained in DNA loops. However, although a dozen of genes have their expression level affected by aging, data on chromatin-nuclear matrix interactions under this physiological condition are still scarce. In the present study, liver imprints from young, adult and old mice were subjected to FISH (fluorescence in situ hybridization) for 45S rDNA and telomeric sequences, with or without a lysis treatment to produce extended chromatin fibres. There was an increased amount of 45S rDNA sequences located in DNA loops as the animals grow older, while telomeric sequences were always observed in DNA loops irrespective of the animal age. We assume that active rRNA genes associate with the nuclear matrix, while DNA loops contain silent sequences. Transcription of each 45S rDNA repeat unit is suggested to be dependent on its interaction with the nuclear matrix.

Susceptibility of the aging lung to environmental injury

With an ever-increasing number of elderly individuals in the world, a better understanding of the issues associated with aging and the environment is needed. The respiratory system is one of the primary interfaces between the body and the external environment. An expanding number of studies suggest that the aging pulmonary system (>65 years) is at increased risk for adverse health effects from environmental insult, such as by air pollutants, infection, and climate change. However, the mechanism(s) for increased susceptibility in this subpopulation are not well understood. In this review, we provide a limited but comprehensive overview of how the lung ages, examples of environmental exposures associated with injury to the aging lung, and potential mechanisms underlying the increased vulnerability of the aging lung to injury from environmental factors.

Adaptive senectitude: the prolongevity effects of aging

In the past, it has been assumed that all the biological and medical changes that occur in old age are deleterious. It has therefore been concluded that treatment and prevention of such changes in old age should increase healthspan and delay death. However, accruing epidemiological and clinical trial evidence in older humans suggests that this is not the case. Some studies have shown that antioxidants and hormone supplements increase mortality, whereas high blood pressure, obesity, and metabolic syndrome are often associated with improved outcomes in very elderly people. Perhaps, some of these supposedly detrimental changes accompanying old age are in fact evolutionary adaptations to prolong life after reproduction in humans. Indeed, a form of reverse antagonistic pleiotropy or adaptive senectitude might be occurring. Some common biological and medical changes in old age might actually enhance longevity and represent novel targets for improving health in older people.

Anti-aging herbal medicine--how and why can they be used in aging-associated neurodegenerative diseases?

Aging is a universal biological process that leads to progressive and deleterious changes in organisms. From ancient time, mankind has already interested in preventing and keeping ourselves young. Anti-aging study is certainly not a new research area. Nowadays, the meaning of anti-aging has been changed from simply prolonging lifespan to increasing health span, which emphasizes more on the quality of life. This is the concept of healthy aging and prevention of pathological aging, which is associated with diseases. Keeping our brain functions as in young age is an important task for neuroscientists to prevent aging-associated neurological disorders, such as Alzheimer's diseases (AD) and Parkinson's disease (PD). The causes of these diseases are not fully understood, but it is believed that these diseases are affected by multiple factors. Neurodegenerative diseases can be cross-linked with a number of aging-associated conditions. Based on this, a holistic approach in anti-aging research seems to be more reasonable. Herbal medicine has a long history in Asian countries. It is believed that many of the medicinal herbs have anti-aging properties. Recent studies have shown that some medicinal herbs are effective in intervention or prevention of aging-associated neurological disorders. In this review, we use wolfberry and ginseng as examples to elaborate the properties of anti-aging herbs. The characteristics of medicinal herbs, especially their applications in different disease stages (prevention and intervention) and multi-targets properties, allow them to be potential anti-aging intervention in prevention and treatment of the aging-associated neurological disorders.

Preliminary phytochemical screening and in vitro antioxidant activities of the aqueous extract of Helichrysum longifolium DC

BACKGROUND

Many oxidative stress related diseases are as a result of accumulation of free radicals in the body. A lot of researches are going on worldwide directed towards finding natural antioxidants of plants origins. The aims of this study were to evaluate in vitro antioxidant activities and to screen for phytochemical constituents of Helichrysum longifolium DC. [Family Asteraceae] aqueous crude extract.

METHODS

We assessed the antioxidant potential and phytochemical constituents of crude aqueous extract of Helichrysum longifolium using tests involving inhibition of superoxide anions, DPPH, H2O2, NO and ABTS. The flavonoid, proanthocyanidin and phenolic contents of the extract were also determined using standard phytochemical reaction methods.

RESULTS

Phytochemical analyses revealed the presence of tannins, flavonoids, steroids and saponins. The total phenolic content of the aqueous leaf extract was 0.499 mg gallic acid equivalent/g of extract powder. The total flavonoid and proanthocyanidin contents of the plant were 0.705 and 0.005 mg gallic acid equivalent/g of extract powder respectively. The percentage inhibition of lipid peroxide at the initial stage of oxidation showed antioxidant activity of 87% compared to those of BHT (84.6%) and gallic acid (96%). Also, the percentage inhibition of malondialdehyde by the extract showed percentage inhibition of 78% comparable to those of BHT (72.24%) and Gallic (94.82%).

CONCLUSIONS

Our findings provide evidence that the crude aqueous extract of H. longifolium is a potential source of natural antioxidants, and this justified its uses in folkloric medicines.

Aging and exercise affect the level of protein acetylation and SIRT1 activity in cerebellum of male rats

Aging is associated with a gradual decline in cognitive and motor functions, the result of complex biochemical processes including pre- and posttranslational modifications of proteins. Sirtuins are NAD(+) dependent protein deacetylases. These enzymes modulate the aging process by lysine deacetylation, which alters the activity and stability of proteins. Exercise can increase mean life-span and improve quality of life. Data from our laboratories revealed that 4 weeks of treadmill running improves performance in the Morris Maze test for young (4 months, old) but not old (30 months, old) male rats, and the exercise could not prevent the age-associated loss in muscle strength assessed by a gripping test. The positive correlation between protein acetylation and the gripping test suggests that the age-dependent decrease in relative activity of SIRT1 in the cerebellum impairs motor function. Similarly to the acetylation level of total proteins, the acetylation of ά -tubulin is also increased with aging, while the effect of exercise training was not found to be significant. Moreover, the protein content of nicotinamide phosphoribosyltransferase, one of the key enzymes of NAD biosynthesis, decreased in the young exercise group. These data suggest that aging results in decreased specific activity of SIRT1 in cerebellum, which could lead to increased acetylation of protein residues, including ά-tubulin, that interfere with motor function.

p66Shc-generated oxidative signal promotes fat accumulation

Reactive oxygen species (ROS) and insulin signaling in the adipose tissue are critical determinants of aging and age-associated diseases. It is not clear, however, if they represent independent factors or they are mechanistically linked. We investigated the effects of ROS on insulin signaling using as model system the p66(Shc)-null mice. p66(Shc) is a redox enzyme that generates mitochondrial ROS and promotes aging in mammals. We report that insulin activates the redox enzyme activity of p66(Shc) specifically in adipocytes and that p66(Shc)-generated ROS regulate insulin signaling through multiple mechanisms, including AKT phosphorylation, Foxo localization, and regulation of selected insulin target genes. Deletion of p66(Shc) resulted in increased mitochondrial uncoupling and reduced triglyceride accumulation in adipocytes and in vivo increased metabolic rate and decreased fat mass and resistance to diet-induced obesity. In addition, p66(Shc-/-) mice showed impaired thermo-insulation. These findings demonstrate that p66(Shc)-generated ROS regulate the effect of insulin on the energetic metabolism in mice and suggest that intracellular oxidative stress might accelerate aging by favoring fat deposition and fat-related disorders.

Peripheral biomarkers of oxidative stress in aging and Alzheimer's disease

Aging is associated with a greatly increased incidence of a number of neurodegenerative disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS). These conditions are associated with chronic inflammation, which generates oxygen reactive species, ultimately responsible for a process known as oxidative stress. It is well established that this process is the culprit of neurodegeneration, and there are also mounting evidences that it is not restricted to the central nervous system. Indeed, several studies, including some by our group, have demonstrated that increased peripheral oxidative stress markers are associated to aging and, more specifically, to AD. Therefore, it is very instigating to regard aging and AD as systemic conditions that might be determined by studying peripheral markers of oxidative stress.

The role of mitochondria in aging of skeletal muscle

Aging can be characterized as a time dependent decline of maximal functionality that affects tissues and organs of the whole body. Such is induced by the progressive loss of redundant components and leads to an increased susceptibility to disease and risk of death. Regarding the aging of skeletal muscle, it has been pointed out that mitochondria is a key factor behind the loss of redundancy and functionality, since this organelle has a major role in cellular homeostasis particularly at the level of the bioenergetic status. Decreased activities of the mitochondrial electron transport chain complexes and an increased release of reactive oxygen species from mitochondria are well documented with age; it is suggested that the mitochondrial loss of function results from the increased oxidative damage to proteins, lipids, and DNA of this organelle. However, it is important to be aware that the mitochondrial loss of function could also be a consequence, rather than a cause, of the cellular deterioration with age, which compromises mitochondrial biogenesis, mitochondrial protein turnover and autophagocytosis of damaged mitochondria. In this review several topics will be addressed regarding the age-related loss of skeletal muscle redundancy associated with mitochondrial dysfunction, emphasizing hypotheses for underlying mechanisms. In addition, we discuss some of the cellular mechanisms that can be pointed out as being responsible for the age-related mitochondrial dysfunction.

Hydrogen peroxide: a metabolic by-product or a common mediator of ageing signals?

The reactive oxygen species that are generated by mitochondrial respiration, including hydrogen peroxide (H2O2), are potent inducers of oxidative damage and mediators of ageing. It is not clear, however, whether oxidative stress is the result of a genetic programme or the by-product of physiological processes. Recent findings demonstrate that a fraction of mitochondrial H2O2, produced by a specialized enzyme as a signalling molecule in the pathway of apoptosis, induces intracellular oxidative stress and accelerates ageing. We propose that genes that control H2O2 production are selected determinants of lifespan.

Nitrative thioredoxin inactivation as a cause of enhanced myocardial ischemia/reperfusion injury in the aging heart

Several recent studies have demonstrated that thioredoxin (Trx) is an important antiapoptotic/cytoprotective molecule. The present study was designed to determine whether Trx activity is altered in the aging heart in a way that may contribute to increased susceptibility to myocardial ischemia/reperfusion (MI/R). Compared to young animals, MI/R-induced cardiomyocyte apoptosis and infarct size were increased in aging animals (p<0.01). Trx activity was decreased in the aging heart before MI/R, and this difference was further amplified after MI/R. Trx expression was moderately increased and Trx nitration, a posttranslational modification that inhibits Trx activity, was increased in the aging heart. Moreover, Trx-aptosis-regulating kinase-1 (Trx-ASK1) complex formation was reduced and activity of p38 mitogen-activated protein kinase (MAPK) was increased. Treatment with FP15 (a peroxynitrite decomposition catalyst) reduced Trx nitration, increased Trx activity, restored Trx-ASK1 interaction, reduced P38 MAPK activity, attenuated caspase 3 activation, and reduced infarct size in aging animals (p<0.01). Our results demonstrated that Trx activity is decreased in the aging heart by posttranslational nitrative modification. Interventions that restore Trx activity in the aging heart may be novel therapies to attenuate MI/R injury in aging patients.

Peroxisomes and aging

Peroxisomes are indispensable for proper functioning of human cells. They efficiently compartmentalize enzymes responsible for a number of metabolic processes, including the absolutely essential beta-oxidation of specific fatty acid chains. These and other oxidative reactions produce hydrogen peroxide, which is, in most instances, immediately processed in situ to water and oxygen. The responsible peroxidase is the heme-containing tetrameric enzyme, catalase. What has emerged in recent years is that there are circumstances in which the tightly regulated balance of hydrogen peroxide producing and degrading activities in peroxisomes is upset-leading to the net production and accumulation of hydrogen peroxide and downstream reactive oxygen species. The factor most essentially involved is catalase, which is missorted in aging, missing or present at reduced levels in certain disease states, and inactivated in response to exposure to specific xenobiotics. The overall goal of this review is to summarize the molecular events associated with the development and advancement of peroxisomal hypocatalasemia and to describe its effects on cells. In addition, results of recent efforts to increase levels of peroxisomal catalase and restore oxidative balance in cells will be discussed.

Serum paraoxonase 1 activity and lipid peroxidation levels in patients with age-related macular degeneration

Our objective was to investigate antioxidant paraoxonase 1 (PON1) activity together with malondialdehyde (MDA) levels to evaluate oxidative stress in patients with age-related macular degeneration (AMD), an important cause of blindness in the elderly population. Serum PON1 activity and MDA levels were analyzed in 37 patients with AMD and compared with 29 healthy controls using a spectrophotometric method. Serum MDA levels were significantly higher in the patient group (2.76 +/- 1.28 nmol/ml) than controls (1.00 +/- 0.36 nmol/ml; p < 0.001), whereas PON1 activity was lower in the patient group (132.27 +/- 63.39 U/l) than controls (312.13 +/- 136.23 U/l; p < 0.001). There was a negative correlation between MDA and PON1 levels (r = -0.470, p < 0.001). We conclude that the observed increase in MDA levels may be related to decreased PON1 activity; the present data also demonstrated that an obvious negative correlation between PON1 activity and MDA levels exists in patients with AMD. PON1 is also an antioxidant agent, therefore effective antioxidant therapy to inhibit lipid peroxidation is necessary and agents to increase PON1 activity may be a therapeutic option in AMD.

Antioxidant approach to disease management and the role of 'Rasayana' herbs of Ayurveda

The disease preventive and health promotive approach of 'Ayurveda', which takes into consideration the whole body, mind and spirit while dealing with the maintenance of health, promotion of health and treating ailments is holistic and finds increasing acceptability in many regions of the world. Ancient Ayurvedic physicians had developed certain dietary and therapeutic measures to arrest/delay ageing and rejuvenating whole functional dynamics of the body system. This revitalization and rejuvenation is known as the 'Rasayan chikitsa' (rejuvenation therapy). Traditionally, Rasayana drugs are used against a plethora of seemingly diverse disorders with no pathophysiological connections according to modern medicine. Though, this group of plants generally possesses strong antioxidant activity, only a few have been investigated in detail. Over about 100 disorders like rheumatoid arthritis, hemorrhagic shock, CVS disorders, cystic fibrosis, metabolic disorders, neurodegenerative diseases, gastrointestinal ulcerogenesis and AIDS have been reported as reactive oxygen species mediated. In this review, the role of free radicals in these diseases has been briefly reviewed. 'Rasayana' plants with potent antioxidant activity have been reviewed for their traditional uses, and mechanism of antioxidant action. Fifteen such plants have been dealt with in detail and some more plants with less work have also been reviewed briefly.

Oxidative state in platelets and erythrocytes in aging and Alzheimer's disease

Several studies have shown involvement of peroxynitrite anion, a potent oxidative agent, in Alzheimer's disease (AD) neuropathology. Herein, we assessed in platelets and erythrocytes of AD patients, age-matched and young adults controls: thiobarbituric acid-reactive substances (TBARS) production; superoxide dismutase (SOD), nitric oxide synthase (NOS) and Na,K-ATPase activities; cyclic GMP (cGMP) content, both basal and after sodium nitroprusside (SNP) stimulation. Aging was associated with an increase in TBARS production and NOS activity, a decrease in basal cGMP content and no change in SOD and Na,K-ATPase activities. AD patients, compared to aged controls, have: increase in TBARS production and in NOS, SOD and Na,K-ATPase activities but no alteration in basal cGMP content. SNP increased cGMP platelets production in all groups. In conclusion, we demonstrated in platelets and erythrocytes a disruption in systemic modulation of oxidative stress in aging and with more intensity in AD.