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

Influence of consumption of the food additive carrageenan on the gut microbiota and the intestinal homeostasis of mice

The safety of the carrageenan (CGN) consumption as a food additive is under debate, with negative effects being associated with the products of hydrolysis of CGN. Moreover, there is an increasing need to integrate gut microbiome analysis in the scientific risk assessment of food additives. The objective of this study was to test the effects of CGN consumption on the gut microbiota and the intestinal homeostasis of young male and female mice. Female and male ICR-CD1 mice (8 weeks old) orally received 540 mg kg-1 day-1 of CGN, representing the maximum-level exposure assessment scenario surveyed for children, over the course of two weeks. Fecal material and peritoneal immune cells were analyzed to determine changes in the fecal microbiota, based on the analysis of bacterial 16S rRNA gene amplicon sequences and short-chain fatty acid (SCFA) concentrations, and some immune functions and redox parameters of peritoneal leukocytes. Non-significant microbiota taxonomical changes associated with CGN intake were found in the mouse stools, resulting the housing time in an increase in bacterial groups belonging to the Bacteroidota phylum. The PICRUSt2 functional predictions showed an overall increase in functional clusters of orthologous genes (COGs) involved in carbohydrate transport and metabolism. A significant increase in the cytotoxicity of fecal supernatants was observed in CGN-fed mice, which correlated with worsening of immune functions and oxidative parameters. The altered immunity and oxidative stress observed in young mice after the consumption of CGN, along with the fecal cytotoxicity shown towards intestinal epithelial cells, may be associated with the gut microbiota's capacity to degrade CGN. The characterization of the gut microbiota's ability to hydrolyze CGN should be included in the risk assessment of this food additive.

Glomerular Hypertrophy and Splenic Red Pulp Degeneration Concurrent with Oxidative Stress in 3xTg-AD Mice Model for Alzheimer's Disease and Its Exacerbation with Sex and Social Isolation

The continuously expanding field of Alzheimer's disease (AD) research is now beginning to defocus the brain to take a more systemic approach to the disease, as alterations in the peripheral organs could be related to disease progression. One emerging hypothesis is organ involvement in the process of Aβ clearance. In the present work, we aimed to examine the status and involvement of the kidney as a key organ for waste elimination and the spleen, which is in charge of filtering the blood and producing lymphocytes, and their influence on AD. The results showed morphological and structural changes due to acute amyloidosis in the kidney (glomeruli area) and spleen (red pulp area and red/white pulp ratio) together with reduced antioxidant defense activity (GPx) in 16-month-old male and female 3xTg-AD mice when compared to their age- and sex-matched non-transgenic (NTg) counterparts. All these alterations correlated with the anxious-like behavioral phenotype of this mouse model. In addition, forced isolation, a cause of psychological stress, had a negative effect by intensifying genotype differences and causing differences to appear in NTg animals. This study further supports the relevance of a more integrative view of the complex interplay between systems in aging, especially at advanced stages of Alzheimer's disease.

Hepatic Oxi-Inflammation and Neophobia as Potential Liver-Brain Axis Targets for Alzheimer's Disease and Aging, with Strong Sensitivity to Sex, Isolation, and Obesity

Research on Alzheimer's disease (AD) has classically focused on alterations that occur in the brain and their intra- and extracellular neuropathological hallmarks. However, the oxi-inflammation hypothesis of aging may also play a role in neuroimmunoendocrine dysregulation and the disease's pathophysiology, where the liver emerges as a target organ due to its implication in regulating metabolism and supporting the immune system. In the present work, we demonstrate organ (hepatomegaly), tissue (histopathological amyloidosis), and cellular oxidative stress (decreased glutathione peroxidase and increased glutathione reductase enzymatic activities) and inflammation (increased IL-6 and TNF𝛼) as hallmarks of hepatic dysfunction in 16-month-old male and female 3xTg-AD mice at advanced stages of the disease, and as compared to age- and sex-matched non-transgenic (NTg) counterparts. Moreover, liver-brain axis alterations were found through behavioral (increased neophobia) and HPA axis correlations that were enhanced under forced isolation. In all cases, sex (male) and isolation (naturalistic and forced) were determinants of worse hepatomegaly, oxidative stress, and inflammation progression. In addition, obesity in old male NTg mice was translated into a worse steatosis grade. Further research is underway determine whether these alterations could correlate with a worse disease prognosis and to establish potential integrative system targets for AD research.

Positive effects of pulsed electromagnetic fields on behavior, immune function, and oxidative and inflammatory state in old mice

The establishment of chronic oxidative and inflammatory stress with aging leads to the deterioration of the nervous and immune systems and, consequently, to the loss of health. The aim of this work was to study the effect of exposure to low-frequency pulsed electromagnetic fields (PEMFs) produced by the NEURALTER® system (15 min/day for 4 weeks) in the behavior, immune functions, and oxidative and inflammatory state of old mice. Female old CD1 mice were divided into three groups: control group, handling control group and Neuralter group. Then, behavioral tests were performed, and peritoneal leukocytes were extracted to analyze function, oxidative and inflammatory parameters. In peritoneal leukocytes from old mice, the effects in vitro of 15 min with NEURALTER® were studied on function and oxidative parameters. The results show that after this type of treatment, old mice had greater coordination and locomotion, better immune function, and an oxidative-inflammatory state. Similarly, the immune function and oxidative state of leukocytes showed an improvement when these cells were exposed directly to the NEURALTER® system. In conclusion, the exposure to low-frequency PEMFs produced by the NEURALTER® system has beneficial effects on health in aging. In addition, this effect is direct, at least in part, on immune cells.

Oxidative stress, inflammation and hormesis: The role of dietary and lifestyle modifications on aging

Oxidative stress (OS) is primarily caused by the formation of free radicals and reactive oxygen species; it is considered as one of the prominent factors in slowing down and degrading cellular machinery of an individual, and it eventually leads to aging and age-related diseases by its continuous higher state. The relation between molecular damage and OS should be particularized to understand the beginning of destruction at the cellular levels, extending outwards to affect tissues, organs, and ultimately to the organism. Several OS biomarkers, which are established at the biomolecular level, are useful in investigating the disease susceptibility during aging. Slowing down the aging process is a matter of reducing the rate of oxidative damage to the cellular machinery over time. The breakdown of homeostasis, the mild overcompensation, the reestablishment of homeostasis, and the adaptive nature of the process are the essential features of hormesis, which incorporates several factors, including calorie restriction, nutrition and lifestyle modifications that play an important role in reducing the OS. In the current review, along with the concept and theories of aging (with emphasis on free radical theory), various manifestations of OS with special attention on mitochondrial dysfunction and age-related diseases have been discussed. To alleviate the OS, hormetic approaches including caloric restriction, exercise, and nutrition have also been discussed.

Skin-to-Skin Contact: Crucial for Improving Behavior, Immunity, and Redox State after Short Cohabitation of Chronologically Old Mice and Prematurely Aging Mice with Adult Mice

(1) Background: Aging is characterized by a deterioration of the homeostatic systems, namely the nervous and immune systems. The rate of aging can be modified by lifestyle factors such as social interactions. Recently, improvements in behavior, immune function, and oxidative state were observed in adult prematurely aging mice (PAM) and chronologically old mice after cohabitation with exceptional non-PAM (E-NPAM) and adult mice, respectively, for 2 months. However, the cause of this positive effect is not known. The objective of the present work was to study whether skin-to-skin contact promotes these improvements both in chronologically old mice and in adult PAM. (2) Methods: Old and adult CD1 female mice were used as well as adult PAM and E-NPAM. After cohabitation for 15 min/day for 2 months (two old mice or PAM with five adult mice or E-NPAM, respectively, with both non- and skin-to-skin contact), several behavioral tests were performed and functions and oxidative stress parameters in peritoneal leukocytes were analyzed. (3) Results: This social interaction improved behavioral responses, immune functions, redox state, and longevity, but only if the animals had skin-to-skin contact. (4) Conclusions: Physical contact seems to be crucial to experiencing the positive effects of social interaction.

A short social interaction between adult and old mice improves the homeostatic systems and increases healthy longevity

The aging process can be influenced by environmental factors, such as the social environment. The continuous cohabitation of the chronologically old mice with adult animals improves them at the behavioral level, immune function, oxidative stress and longevity, but causes a deterioration of these parameters in adults. Therefore, the objective of the study was to study whether the coexistence for only 15 min a day of old mice with adult mice, can produce that improvement and greater longevity in old animals without causing deterioration in adults. For that, old and adult CD1 female mice, after two months of that social interaction, were submitted to a behavioral battery and then peritoneal leukocytes were collected to assess several immune functions, oxidative and inflammatory stress parameters as well as catecholamine concentrations. When the adult mice reached old age, the same parameters were again analyzed. The life span of each animal was also recorded. Plasmatic concentration of oxytocin was also studied. The results showed that old mice presented better behavioral capacity, immunity and oxi-inflammatory state after this social interaction with adult animals, and consequently an extended life span. Adult mice, in general, did not show any changes after social interaction with old animals, but when they achieved old age, improvements of some parameters and of longevity were observed in comparison with animals that never had a that social interaction. In conclusion, a short social interaction between old and adult individuals can be an excellent strategy for improving in both the health state and longevity.

Daily ingestion of Akkermansia mucciniphila for one month promotes healthy aging and increases lifespan in old female mice

The ingestion of certain probiotics has been suggested as a promising nutritional strategy to improve aging. The objective of this work was to evaluate the effects of the daily intake, for a month, of a new probiotic Akkermansia muciniphila (AKK) (2 × 10⁸ cfu/100µL PBS) on behavior, as well as function and redox state of immune cells of old female ICR-CD1 mice (OA group). For this, several behavioral tests were performed, and function and oxidative-inflammatory stress parameters of peritoneal leukocytes were analyzed in OA group, in a group of the same age that did not take AKK (old control, OC group) and in another adult control (AC) group. The results showed, in OA group, a significant improvement of several behavioral responses (coordination, balance, neuromuscular vigor, exploratory ability and anxiety like-behaviors), as well as in immune functions (chemotaxis, phagocytosis, NK activity and lymphoproliferation) and in oxidative stress parameters (glutathione peroxidase and reductase activities, oxidized glutathione and lipid oxidation concentrations) of the peritoneal leukocytes in comparison to those observed in OC group. In addition, peritoneal immune cells from the OA group released lower basal concentrations of pro-inflammatory cytokines (IL-2, IL-6 and TNF-α) compared to those from the OC group. The values of parameters in OA were similar to those in AC group. These improvements in the old mice receiving the probiotic were reflected in an increase in their lifespan. In conclusion, our data indicate that AKK supplementation for a short period could be a good nutritional strategy to promote healthy longevity.

Genotype Load Modulates Amyloid Burden and Anxiety-Like Patterns in Male 3xTg-AD Survivors despite Similar Neuro-Immunoendocrine, Synaptic and Cognitive Impairments

The wide heterogeneity and complexity of Alzheimer’s disease (AD) patients’ clinical profiles and increased mortality highlight the relevance of personalized-based interventions and the need for end-of-life/survival predictors. At the translational level, studying genetic and age interactions in a context of different levels of expression of AD-genetic-load can help to understand this heterogeneity better. In the present report, a singular cohort of long-lived (19-month-old survivors) heterozygous and homozygous male 3xTg-AD mice were studied to determine whether their AD-genotype load can modulate the brain and peripheral pathological burden, behavioral phenotypes, and neuro-immunoendocrine status, compared to age-matched non-transgenic controls. The results indicated increased amyloid precursor protein (APP) levels in a genetic-load-dependent manner but convergent synaptophysin and choline acetyltransferase brain levels. Cognitive impairment and HPA-axis hyperactivation were salient traits in both 3xTg-AD survivor groups. In contrast, genetic load elicited different anxiety-like profiles, with hypoactive homozygous, while heterozygous resembled controls in some traits and risk assessment. Complex neuro-immunoendocrine crosstalk was also observed. Bodyweight loss and splenic, renal, and hepatic histopathological injury scores provided evidence of the systemic features of AD, despite similar peripheral organs’ oxidative stress. The present study provides an interesting translational scenario to study further genetic-load and age-dependent vulnerability/compensatory mechanisms in Alzheimer’s disease.

Oxidative stress, antioxidants, hormesis and calorie restriction: The current perspective in the biology of aging

Aging, in a large measure, has long been defined as the resultant of oxidative stress acting on the cells. The cellular machinery eventually malfunctions at the basic level by the damage from the processes of oxidation and the system starts slowing down because of intrinsic eroding. To understand the initial destruction at the cellular level spreading outward to affect tissues, organs and the organism, the relationship between molecular damage and oxidative stress is required to understand. Retarding the aging process is a matter of cumulatively decreasing the rate of oxidative damage to the cellular machinery. Along with the genetic reasons, the decrease of oxidative stress is somehow a matter of lifestyle and importantly of diet. In the current review, the theories of aging and the understanding of various levels of molecular damage by oxidative stress have been emphasized. A broader understanding of mechanisms of aging have been elaborated in terms of effects of oxidative at molecular, mitochondrial, cellular and organ levels. The antioxidants supplementation, hormesis and calorie restriction as the prominent anti-aging strategies have also been discussed. The relevance and the efficacy of the antiaging strategies at system level have also been presented.

The supplementations with 2-hydroxyoleic acid and n-3 polyunsaturated fatty acids revert oxidative stress in various organs of diet-induced obese mice

Obesity and its related diseases have been associated with oxidative stress. Thus, the search for nutritional strategies to ameliorate oxidative stress in obese individuals seems important. We hypothesized that the supplementation with monounsaturated (2-hydroxyoleic acid (2-OHOA)) and with combined n-3 polyunsaturated (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) fatty acids would ameliorate oxidative stress in different organs, including brain, liver, lungs, and kidneys of adult diet-induced obese (DIO) mice. Adult female ICR-CD1 mice were fed a high-fat diet (HFD) for 14 weeks. During the last 6 weeks of HFD feeding, one group of DIO mice received the same HFD, supplemented with 1500 mg of 2-OHOA per kg of HFD and another group with 1500 mg of EPA and 1500 mg of DHA per kg of HFD. At the end of the experiment, several parameters of oxidative stress were assessed. The supplementation with 2-OHOA or with EPA and DHA in DIO mice was able to revert oxidative stress, enhancing the activities of catalase and glutathione reductase, as well as diminishing the activity of xanthine oxidase, the concentration of thiobarbituric acid reactive substances (TBARS) and the ratio between oxidized glutathione and reduced glutathione in several organs. These reached similar values to those of control mice, which were fed a standard diet. These data suggest that supplementation with 2-OHOA and with EPA and DHA could be an effective nutritional intervention to restore an appropriate redox state in DIO mice.

The ratio of prematurely aging to non-prematurely aging mice cohabiting, conditions their behavior, immunity and lifespan

Adult prematurely aging mice (PAM) show behavioral deterioration, premature immunosenescence and increased oxidative stress, impairments that are associated with their shorter lifespan, compared to the corresponding exceptional non-prematurely aging mice (ENPAM). When PAM live in a predominantly ENPAM environment (2/5, respectively) they exhibit an improvement of immunity and redox state in their spleen and thymus leukocytes, and an increased lifespan. Nevertheless, it is unknown if other PAM/ENPAM ratios could affect behavioral and peritoneal leukocyte functions of PAM and change their lifespan. ENPAM and PAM were divided into the following groups: C-ENPAM (8 ENPAM in the cage); C-PAM (8 PAM in the cage); ENPAM>50% and PAM<50% (5 ENPAM/2 PAM in each cage); ENPAM = 50% and PAM = 50% (4 ENPAM/4 PAM in each cage), and PAM>50% and ENPAM<50% (5 PAM/2 ENPAM in each cage). After two months, mice were submitted to a battery of behavioral tests. Several functions and oxidative stress parameters were then assessed in their peritoneal leukocytes. Animals were maintained in these conditions to analyze their lifespan. The results showed that PAM>50%, PAM = 50% and PAM<50% exhibited better behavioral responses, immunity and redox states in their peritoneal leukocytes than C-PAM. This improvement was higher when the number of ENPAM in the cage was increased, with most of the parameters in PAM<50% reaching similar values to those in C-ENPAM, and an increased lifespan. However, ENPAM that cohabited with PAM showed, in general, an impairment of parameters studied. In conclusion, the PAM/ENPAM cohabitation ratio is relevant to behavior and immunity.

Impacts of the late adulthood diet-induced obesity onset on behavior, immune function, redox state and life span of male and female mice

The aim of the present study was to investigate whether the late onset of diet-induced obesity (DIO) in middle-aged mice affected behavioral, immunological and oxidative stress parameters as well as life span of male and female mice. Also, it was analyzed whether the late DIO onset aggravated immunosenescence in old female mice. Late-adult male and female ICR/CD1 mice (28 weeks old) were fed either a high-fat diet or a standard diet during 14 weeks. After that, in these middle-aged (42 weeks old) diet-induced obese (DIO) and non-DIO controls, behavior as well as functions and redox state of peritoneal leukocytes were evaluated. These same parameters (excepting behavioral tests) were repeated when female mice were old (72 weeks old). The results showed lower exploratory activity and higher anxiety-like behavior in middle-aged male and female DIO than in controls. Moreover, these DIO animals from both sexes exhibited statistically significant impaired immune cell functions, such as chemotaxis of macrophages and lymphocytes, phagocytosis of macrophages, natural killer activity and lymphoproliferation in response to ConA and LPS, as well as an oxidative stress state in comparison with controls. Male DIO mice exhibited higher impairments in a variety of the evaluated parameters and a shorter life span than their female counterparts. In addition, female DIO mice, at old age, showed aggravated immunosenescence. In conclusion, the late DIO onset leads to impairments in behavior as well as in immune system functions of middle-aged male and female mice, males being significantly more affected than females.

Oxidative-Inflammatory Stress in Immune Cells from Adult Mice with Premature Aging

Oxidative and inflammatory stresses are closely related processes, which contribute to age-associated impairments that affect the regulatory systems such as the immune system and its immunosenescence. Therefore, the aim of this work was to confirm whether an oxidative/inflammatory stress occurs in immune cells from adult mice with premature aging, similar to that shown in leukocytes from chronologically old animals, and if this results in immunosenescence. Several oxidants/antioxidants and inflammatory/anti-inflammatory cytokines were analyzed in peritoneal leukocytes from adult female CD1 mice in two models of premature aging—(a) prematurely aging mice (PAM) and (b) mice with the deletion of a single allele (hemi-zygotic: HZ) of the tyrosine hydroxylase (th) gene (TH-HZ), together with cells from chronologically old animals. Several immune function parameters were also studied in peritoneal phagocytes and lymphocytes. The same oxidants and antioxidants were also analyzed in spleen and thymus leukocytes. The results showed that the immune cells of PAM and TH-HZ mice presented lower values of antioxidant defenses and higher values of oxidants/pro-inflammatory cytokines than cells from corresponding controls, and similar to those in cells from old animals. Moreover, premature immunosenescence in peritoneal leukocytes from both PAM and TH-HZ mice was also observed. In conclusion, adult PAM and TH-HZ mice showed oxidative stress in their immune cells, which would explain their immunosenescence.

Polysaccharides with Antioxidative and Antiaging Activities from Enzymatic-Extractable Mycelium by Agrocybe aegerita (Brig.) Sing

This study aimed to investigate the antioxidant, antiaging, and organ protective effects of the water-extractable mycelium polysaccharides (MPS) and enzymic-extractable mycelium polysaccharides (En-MPS) by Agrocybe aegerita (Brig.) Sing in D-galactose-induced (D-gal-induced) aging mice. In in vitro assays, the En-MPS demonstrated stronger antioxidant activities in dose-dependent manners. The mice experiments revealed that both En-MPS and MPS had potential effects on antioxidation, antiaging, and organ protection mainly by improving the antioxidant enzyme activities, decreasing the lipid peroxidation, and remitting the lipid metabolism. Furthermore, chemical composition and monosaccharide composition of polysaccharides were also measured, and the results indicated that differences in biological activity of MPS and En-MPS samples showed a significant correlation to their purity. The findings demonstrated that the polysaccharides by A. aegerita (Brig.) Sing could be exploited as natural and functional foods for the prevention and alleviation of aging and its complications.

Premature aging in behavior and immune functions in tyrosine hydroxylase haploinsufficient female mice. A longitudinal study

Aging is accompanied by impairment in the nervous, immune, and endocrine systems as well as in neuroimmunoendocrine communication. In this context, there is an age-related alteration of the physiological response to acute stress, which is modulated by catecholamine (CA), final products of the sympathetic-adreno-medullary axis. The involvement of CA in essential functions of the nervous system is consistent with the neuropsychological deficits found in mice with haploinsufficiency (hemizygous; HZ) of tyrosine hydroxylase (TH) enzyme (TH-HZ). However, other possible alterations in regulatory systems have not been studied in these animals. The aim of the present work was to analyze whether adult TH-HZ female mice presented the impairment of behavioral traits and immunological responses that occurs with aging and whether they had affected their mean lifespan. ICR-CD1 female TH-HZ and wild type (WT) mice were used in a longitudinal study. Behavioral tests were performed on adult and old mice in order to evaluate their sensorimotor abilities and exploratory capacity, as well as anxiety-like behaviors. At the ages of 2 ± 1, 4 ± 1, 9 ± 1, 13 ± 1 and 20 ± 1 months, peritoneal leukocytes were extracted and several immune functions were assessed (phagocytic capacity, Natural Killer (NK) cytotoxicity, and lymphoproliferative response to lipopolysaccharide (LPS) and concanavalin A (ConA)). In addition, several oxidative stress parameters (catalase, glutathione reductase and glutathione peroxidase activities, and reduced glutathione (GSH) concentrations as antioxidant compounds as well as xanthine oxidase activity, oxidized glutathione (GSSG) concentrations, and GSSG/GSH ratio as oxidants) were analyzed. As inflammatory stress parameters TNF-alpha and IL-10 concentrations, and TNF-alpha/IL-10 ratios as inflammatory/anti-inflammatory markers, were measured. Animals were maintained in standard conditions until their natural death. The results indicate that adult TH-HZ mice presented worse sensorimotor abilities and exploratory capacity than their WT littermates as well as greater anxiety-like behaviors. With regards to the immune system, adult TH-HZ animals exhibited lower values of phagocytic capacity, NK cytotoxicity, and lymphoproliferative response to LPS and ConA than WT mice. Moreover, immune cells of TH-HZ mice showed higher oxidative and inflammatory stress than those of WT animals. Although these differences between TH-HZ and WT, in general, decreased with aging, this premature immunosenescence and impairment of behavior of TH-HZ mice was accompanied by a shorter mean lifespan in comparison to WT counterparts. In conclusion, haploinsufficiency of th gene in female mice appears to provoke premature aging of the regulatory systems affecting mean lifespan.

Administration of a leptin antagonist during the neonatal leptin surge induces alterations in the redox and inflammatory state in peripubertal /adolescent rats

The importance of the neonatal leptin surge in rodents in neurodevelopmental processes has aroused curiosity in its implication in other physiological systems. Given the role of leptin in neuro-immune interactions, we hypothesized that the neonatal leptin surge could have an effect on the oxidative and inflammatory stress situations of both systems. We blocked the neonatal leptin surge by a leptin antagonist and measured several parameters of oxidative and inflammatory stress in the spleen, hypothalamus and adipose tissue of peripubertal/adolescent rats. The treated rats showed lower activity of several antioxidant enzymes in the spleen and their leukocytes released lower levels of mitogen-stimulated IL-10 and IL-13 and higher levels of TNF-alpha. In conclusion, the neonatal leptin surge may have a key role in the establishment of adequate redox and inflammatory states in the immune system, which is important for the generation of adequate immune responses and to obtain and maintain good health.

Induction of cellular and molecular Immunomodulatory pathways by vitamin E and vitamin C

INTRODUCTION

Vitamins E and C are well known small molecules that have been used to maintain health for decades. Recent studies of the cellular and molecular pathways leading to immunomodulation by these molecules have been of interest, as have their anti-oxidant properties and signal transduction pathways for curing or improving infectious diseases and cancer. Areas covered: Herein, the authors provide a definition and the structural classification of vitamins E and C and how these molecules influence cellular function. The studies include in vitro, ex vivo and in vivo studies in animal models as well as clinical trials. The authors give particular focus to the scientifically factual and putative roles of these molecules in innate and adaptive immunomodulation and prevention or cure of diseases. Expert opinion: The antioxidant properties of vitamins E and C are well studied. However, whether there is a link between their antioxidant and immunomodulation properties is unclear. In addition, there is a strong, albeit putative, prevailing notion that vitamin C can prevent or cure infectious diseases or cancer. Presently, while there is proven evidence that vitamin E possesses immunomodulatory properties that may play a positive role in disease outcomes, this evidence is less available for vitamin C.

Role of macrophages in age-related oxidative stress and lipofuscin accumulation in mice

The age-related changes in the immune functions (immunosenescence) may be mediated by an increase of oxidative stress and damage affecting leukocytes. Although the “oxidation-inflammation” theory of aging proposes that phagocytes are the main immune cells contributing to “oxi-inflamm-aging”, this idea has not been corroborated. The aim of this work was to characterize the age-related changes in several parameters of oxidative stress and immune function, as well as in lipofuscin accumulation (“a hallmark of aging”), in both total peritoneal leukocyte population and isolated peritoneal macrophages. Adult, mature, old and long-lived mice (7, 13, 18 and 30 months of age, respectively) were used. The xanthine oxidase (XO) activity-expression, basal levels of superoxide anion and ROS, catalase activity, oxidized (GSSG) and reduced (GSH) glutathione content and lipofuscin levels, as well as both phagocytosis and digestion capacity were evaluated. The results showed an age-related increase of oxidative stress and lipofuscin accumulation in murine peritoneal leukocytes, but especially in macrophages. Macrophages from old mice showed lower antioxidant defenses (catalase activity and GSH levels), higher oxidizing compounds (XO activity/expression and superoxide, ROS and GSSG levels) and lipofuscin levels, together with an impaired macrophage functions, in comparison to adults. In contrast, long-lived mice showed in their peritoneal leukocytes, and especially in macrophages, a well-preserved redox state and maintenance of their immune functions, all which could account for their high longevity. Interestingly, macrophages showed higher XO activity and lipofuscin accumulation than lymphocytes in all the ages analyzed. Our results support that macrophages play a central role in the chronic oxidative stress associated with aging, and the fact that phagocytes are key cells contributing to immunosenescence and “oxi-inflamm-aging”. Moreover, the determination of oxidative stress and immune function parameters, together with the lipofuscin quantification, in macrophages, can be used as useful markers of the rate of aging and longevity.

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Peritoneal macrophages from old mice have higher oxidant levels than lymphocytes.

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Long-lived mice have a well-preserved redox state in both macrophages and lymphocytes.

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Peritoneal macrophages have higher lipofuscin levels than lymphocytes along aging.

Antioxidant and anti-aging activities of polysaccharides from Calocybe indica var. APK2

The crude polysaccharides were extracted from the fruiting bodies of Calocybe indica (CIP). The antioxidant activities of CIP were evaluated both in vitro and in vivo. Chemical characteristics of the polysaccharides were investigated. In in vitro antioxidant assay, CIP showed noticeable 2,2-diphenyl-1-picryl-hydrazyl (DPPH), hydroxyl radical scavenging activities, reducing power and lipid peroxidation inhibition. Chemical analysis showed the presence of carbohydrate, protein and the FTIR spectra revealed the presence of general characteristic absorption peak of the polysaccharides. For in vivo antioxidant activity, two different doses of CIP were orally administrated over a period of 6 weeks in a d-galactose (d-gal) induced aged mice model. Significantly lowered activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), levels of glutathione (GSH) and elevated malondialdehyde (MDA) levels were observed in brain and serum of d-galactose induced rats, when compared to control rats. Administration of CIP significantly raised the activities of SOD, CAT, GPx, levels of GSH and lowered the levels of MDA in mice brain and serum in a dose-dependent manner. The results suggested that CIP had potent antioxidant activity and could minimize the occurrence of age-associated disorders associated with involvement of free radicals.

[Premature immunosenescence in catecholamines syntesis deficient mice. Effect of social environment]

INTRODUCTION

Healthy state depends on the appropriate function of the homeostatic systems (nervous, endocrine and immune systems) and the correct communication between them. The functional and redox state of the immune system is an excellent marker of health, and animals with premature immunosenescence show a shorter lifespan. Since catecholamines modulate the function of immune cells, the alteration in their synthesis could provoke immunosenescence. The social environment could be a strategy for modulating this immunosenescence.

AIM

To determine if an haploinsufficiency of tyrosine hydroxylase (TH), the limiting enzyme of synthesis of catecholamines, may produce a premature immunosenescence and if this immunosenescence could be modulated by the social environment.

MATERIALS AND METHODS

Adult (9±1 months) male ICR-CD1 mice with deletion of a single allele (hemi-zygotic: HZ) of the tyrosine hydroxylase enzyme (TH-HZ) and wild-type (WT) mice were used. Animals were housed in four subgroups: WT>50% (in the cage, the proportion of WT mice was higher than 50% in relation to TH-HZ), WT<50%, TH-HZ<50% and TH-HZ>50%. Peritoneal leukocytes were collected and phagocytosis, chemotaxis and proliferation of lymphocytes in the presence of lipopolysaccharide were analyzed. Glutathione reductase and glutathione peroxidase activities as well as oxidized/reduced glutathione ratio were studied.

RESULTS

TH-HZ>50% mice showed a deteriorated function and redox state in leukocytes respect to WT>50% and similar to old mice. However, TH-HZ<50% animals had similar values to those found in WT<50% mice.

CONCLUSION

The haploinsufficiency of TH generates premature immunosenescence, which appears to be compensated by living together with an appropriate number of WT animals.

Impaired responses to gliadin and gut microbes of immune cells from mice with altered stress-related behavior and premature immune senescence

Stress is associated with impaired communication between the nervous and immune systems leading to immunosenescence and increased disease risk. We investigated whether leukocytes from mice with altered stress-related behavior and premature immunosenescence, as well as from chronologically aged mice differently responded ex vivo to celiac disease (CD) triggers (gliadin) and intestinal bacteria by ELISA and flow cytometry and differed in microbiota composition. We found that altered stress-related behavior and premature immunosenescence led to alterations in T lymphocytes and cytokine release of immune cells basally and in response to peptic fragments of gliadin and commensal and pathogenic bacteria, possibly increasing susceptibility to CD in adulthood.

The aged-related increase in xanthine oxidase expression and activity in several tissues from mice is not shown in long-lived animals

Xanthine oxidase (XO) is an important source of oxidant production and plays an essential role in several oxidative stress-related diseases. Aging is associated with a progressive deregulation of homeostasis as a result of a chronic oxidative stress situation. In the present work the age-related changes in XO expression and activity, as well as the activities of superoxide dismutase and catalase have been investigated in liver, kidney and thymus from four different age groups of mice, including long-lived animals. Furthermore, we have evaluated the contribution of the XO to the oxidative stress-associated with aging, in comparison to another enzymatic key source of oxidant generation, the NADPH oxidase, in peritoneal leukocytes from old mice. In all the tissues analyzed, the old mice showed higher activity and expression of XO, and decreased or unchanged superoxide dismutase and catalase activities as compared with adult mice. Moreover, the inhibition of reactive oxygen species with allopurinol or apocynin in peritoneal leukocytes from old mice, suggest that both XO and NADPH oxidase contribute to the generation of superoxide anion, whereas the XO may have a special relevance in the production of hydrogen peroxyde. Finally, long-lived animals showed a well-preserved redox state, in terms of antioxidant defenses and oxidant compounds in tissues and immune cells, which may be related to the ability of these subjects to reach a very advanced age in healthy condition. These results confirm that XO plays an important role in the age-related oxidative stress in tissues and immune cells.

Soybean and green tea polyphenols improve immune function and redox status in very old ovariectomized mice

In previous work we have observed that ovariectomy in rodents, a good model of mimicking human ovarian hormone loss, causes premature aging of the immune system. The prooxidative and inflammatory state that underlies the aging process is the base of that premature immunosenescence. It has been found that nutritional interventions with polyphenolic antioxidants constitute a good alternative to rejuvenate age-affected immune functions. In this study, we administered a diet supplemented with polyphenols (coming from soybean isoflavones and green tea) to sham-operated and ovariectomized mature mice for 15 weeks, until they reached a very old age. We have studied the effect of this supplementation on a broad range of parameters of immune function (in macrophages and lymphocytes) and oxidative stress (enzymatic and nonenzymatic antioxidant defences, oxidant compounds, and lipid peroxidation damage) in peritoneal leukocytes. The results showed that ovariectomy accelerates the age-related impairment of immune functions in very old mice as well as the oxidative and proinflammatory imbalance, and that the administration of soybean isoflavones and green tea improve the immune and redox state in these animals. Because the immune system is a good marker of health and a predictor of longevity, we suggest that an adequate nutritional treatment with polyphenols could be a highly recommended tool to fight against the detrimental effects of the lack of female sex hormones, through an improvement of the immune cell functions and redox state.

Murine models of premature ageing for the study of diet-induced immune changes: improvement of leucocyte functions in two strains of old prematurely ageing mice by dietary supplementation with sulphur-containing antioxidants

Several immune functions are markers of health, biological age and predictors of longevity. A chronic oxidative and inflammatory state is the main cause of ageing and the immune system is involved in the rate of ageing. Thus, several murine models of premature ageing have been proposed owing to their early immunosenescence and oxidative stress, such as ovariectomised rats and mice, obese rats and anxious mice. In the last model, the most extensively studied by us, mice showing anxiety have an aged immune function and redox status as well as a shorter longevity in comparison with animals without anxiety of the same chronological age, being denominated prematurely ageing mice. A confirmation of the above is that the administration of diets supplemented with antioxidants improves the redox status and immune functions and increases the longevity of prematurely ageing mice. Antioxidant precursors of glutathione such as thioproline or N-acetylcysteine, which have a relevant role in ageing, have been the most widely investigated in adult prematurely ageing mice in our laboratory. In the present work, we have studied the effects of the ingestion for 5 weeks of a diet supplemented with 0·1% (w/w) thioproline+N-acetylcysteine on several functions of leucocytes from chronological old (69-73 weeks of age) prematurely ageing mice of two strains (Swiss and BALB/c). The results show an improvement of the immune functions, with their values becoming closer to those in adult animals (24±2 weeks). Thus, an adequate nutrition with antioxidants, even in aged subjects, could be a good strategy to retard ageing.

Effects of growth hormone, melatonin, oestrogens and phytoestrogens on the oxidized glutathione (GSSG)/reduced glutathione (GSH) ratio and lipid peroxidation in aged ovariectomized rats

Ovariectomy constitutes a commonly used model in rats and mice for human menopause. After ovariectomy, an imbalance between oxidant production and antioxidant levels appears in favour of the former, with increased oxidative stress and consequently an acceleration of ageing. In the present work, the levels of reduced glutathione (GSH), a relevant antioxidant, and oxidized glutathione (GSSG), an oxidant compound, as well as lipid peroxidation (through malondialdehyde (MDA) levels), were studied in liver, heart, kidney and spleen homogenates of old (24 months of age) unovariectomized and ovariectomized female Wistar rats. The results showed a significant increase of the GSSG/GSH ratio, a marker of oxidative stress, and higher MDA production in all the studied organs of ovariectomized rats as compared with unovariectomized animals. These data confirm the idea that ovariectomy accelerates the ageing process. Administration of growth hormone (GH), melatonin (MEL) and oestrogens (OE), as well as soybean phytoestrogens (PE) for 10 weeks, between 22 and 24 months of age, was able to decrease oxidative stress in the investigated organs of ovariectomized old rats, therefore slowing down the ageing process in those animals.

Comparative proteome analysis of splenic lymphocytes in long-term high-fat diet and dietary supplement with lipoic acid mice

The objective of this investigation was to explore possible molecular changes for role of a high-fat diet (HFD)-induced oxidative stress in splenic lymphocytes, and whether a dietary lipoic acid (LA) supplement could attenuate these changes. Male C57BL/6 mice were fed one of three diets 10 weeks and outcome measures centered on parameters of oxidative stress and lymphocytes apoptosis in spleen. Two-dimensional gel electrophoresis was used to compare the proteomes of splenic lymphocytes with three dietary groups. Differentially expressed spots whose expression altered over three fold were identified by MALDI-TOF MS. In this study, HFD resulted in oxidative stress in mice spleen, and significantly increased apoptotic percentage of splenic lymphocytes. Bioinformatic evaluation results of MALDI-TOF MS showed that 20 differentially expressed protein spots were known to be involved in many processes associated with cell function, such as cytoskeleton, energy metabolism and oxidative stress, signal transduction and cell defense. In conclusion, these results indicate that HFD-induced oxidative stress could lead to the functional decline of splenic lymphocytes, and LA supplement attenuates the alterations of protein expression to maintain the basic biological processes.

Aging and the immune system

Aging is associated with many physiological changes in a variety of organ systems. Nevertheless, considerable interest has centred on the possibility that age-related immunological changes may play a key "master" role in regulating many, if not all, subsequent events. A growing body of data, some of it highlighted in this review, supports the notion that host resistance in general is changed in both a qualitative and quantitative manner with age, though the biochemical mechanism(s) underlying such changes are not unique to the immune system per se. Moreover, interventions designed to explore treatments which may reverse some or all of those age-related changes have pointed out a fundamentally important role for nutrition, and the way(s) in which this impacts on host resistance mechanism(s), as having a hitherto unappreciated importance in immunosenescence in general.

[Immunological markers of ageing]

Ageing is a process involving morphological and physiological modifications that gradually appear with time and lead to death. Given the heterogeneous nature of the process among individuals and among the different organs, tissues, and systems in the same individual, the concept of <<biological age>> has been developed. The search for parameters that enable us to evaluate biological age--and therefore longevity--and the analysis of the efficacy of strategies to retard the ageing process are the objectives of gerontology. At present, one of the most important theories of ageing is the <<oxidative-inflammatory>> theory. Given that immune cell function is an excellent marker of health, we review the concepts that enable different functional and oxidative stress parameters in immune cells to be identified as markers of biological age and longevity. None of these parameters is universally accepted as a biomarker of ageing, although they are becoming increasingly important.

Effects of multivitamin supplementation on DNA damage in lymphocytes from elderly volunteers

The aim of this study was to evaluate the effect of a mixture of vitamins and minerals on oxidative DNA damage and the resistance of DNA to H(2)O(2)-induced DNA strand breaks in lymphocytes from 80 elderly volunteers ex vivo by means of Comet assay. The intervention with vitamin complex decreased significantly the levels of DNA damage. Our results demonstrate that the vitamin complex was able to decrease H(2)O(2)-induced DNA breakage. Our data suggest that the consumption of some vitamins may reduce the effects of oxidative DNA damage and may be useful for attaining healthy aging.

Effect of the Lycium barbarum polysaccharides on age-related oxidative stress in aged mice

Oxidative damage of biomolecules increases with age and is postulated to be a major causal factor of various physiological function disorders. Consequently, the concept of anti-age by antioxidants has been developed. Lycium barbarum fruits have been used as a traditional Chinese herbal medicine and the data obtained in in vitro models have clearly established the antioxidant potency of the polysaccharides isolated from the fruits. In the present study, the age-dependent changes in the antioxidant enzyme activity, immune function and lipid peroxidation product were investigated and effect of Lycium barbarum polysaccharides on age-induced oxidative stress in different organs of aged mice was checked. Lycium barbarum polysaccharides (200, 350 and 500 mg/kg b.w. in physiological saline) were orally administrated to aged mice over a period of 30 days. Aged mice receiving vitamin C served as positive control. Enzymatic and non-enzymatic antioxidants, lipid peroxides in serum and tested organs, and immune function were measured. Result showed that increased endogenous lipid peroxidation, and decreased antioxidant activities, as assessed by superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (TAOC), and immune function were observed in aged mice and restored to normal levels in the polysaccharides-treated groups. Antioxidant activities of Lycium barbarum polysaccharides can be compable with normal antioxidant, vitamin C. Moreover, addition of vitamin C to the polysaccharides further increased the in vivo antioxidant activity of the latter. It is concluded that the Lycium barbarum polysaccharides can be used in compensating the decline in TAOC, immune function and the activities of antioxidant enzymes and thereby reduces the risks of lipid peroxidation accelerated by age-induced free radical.

A model of premature aging in mice based on altered stress-related behavioral response and immunosenescence

The intensity of behavioral and neuroendocrine responses to stressful stimuli in rodent strains seems to be inversely related to their life span. We have previously shown that interindividual differences in members of outbred Swiss and inbred BALB/c mouse populations, both male and female, may be related to their behavior in a simple T-maze test. The animals that explore the maze slowly show impaired neuromuscular vigor and coordination, decreased locomotor activity, increased level of emotionality/anxiety, decreased levels of brain biogenic amines as well as immunosenescence and decreased life span, when compared to their control counterparts, which quickly explore the maze. These traits are similar to some of the alterations previously observed in aging animals and therefore we proposed that those 'slow mice' are biologically older than the fast animals and may be a model of prematurely aging mice (PAM). Although most of our work on this model has been performed on chronologically adult-mature animals, we have also shown that certain characteristics of PAM, such as increased anxiety and deficient immune response, are already present in chronologically young animals. Thus, it is tempting to hypothesize that chronic hyperreactivity to stress (trait anxiety) leading to immune dysfunction may have a causal relationship with impaired health and premature aging. In view of the link between oxidative stress and the aging process, the redox state of peritoneal leukocytes from PAM has been studied, showing an oxidative stress situation. In the present work we have determined the levels of a key antioxidant, reduced glutathione (GSH), and the oxidant malondialdehyde (MDA), a marker of lipid peroxidation, both in the spleen and brain of male and female PAM and non-PAM (NPAM). We found that GSH and MDA are decreased and increased, respectively, in PAM with respect to NPAM. Moreover, diet supplementation with antioxidants showed to be an effective strategy for protection against early immune and behavioral decline, altered redox state of leukocytes and premature mortality in PAM, which supports the validity of this model of premature aging as well as its link with oxidative stress.