Preserved ex vivo inflammatory status and cytokine responses in naturally long-lived mice

Cannabidiol, a Strategy in Aging to Improve Redox State and Immunity in Male Rats

Aging is characterized by oxidative stress and immune function impairment, and is associated with increased morbidity. Cannabidiol (CBD) has anti-oxidant properties, but its role in aging has been scarcely studied. This work aims to test the effect of CBD on the redox state and immunity during aging in rats. In this study, 15-month-old male Long Evans rats received 10 mg/kg b.w/day of CBD in their diet for 10 weeks and were compared with same-age control and 2-month-old rats serving as a young control group, both following a standard diet. After treatment, they were sacrificed, and the spleen, thymus, and total blood cells were collected. Redox parameters such as glutathione reductase and peroxidase activities, reduced (GSH) and oxidized (GSSG) glutathione concentration, GSSG/GSH ratio, and lipid peroxidation were evaluated. Moreover, immune functions (chemotaxis, natural killer activity, and lymphoproliferation) were analyzed in the spleen. Results show that the 15-month-old control rats exhibited increased oxidative stress and immunosenescence compared to the 2-month-old rats. However, the CBD-treated animals showed higher anti-oxidant defenses, lower oxidants in the spleen, thymus, and blood cells, and better immunity in the spleen than the corresponding age-matched controls. Therefore, CBD administration neutralizes oxidative stress and improves immunity, suggesting it is a strategy for achieving healthy aging.

Accelarated immune ageing is associated with COVID-19 disease severity

BACKGROUND

The striking increase in COVID-19 severity in older adults provides a clear example of immunesenescence, the age-related remodelling of the immune system. To better characterise the association between convalescent immunesenescence and acute disease severity, we determined the immune phenotype of COVID-19 survivors and non-infected controls.

RESULTS

We performed detailed immune phenotyping of peripheral blood mononuclear cells isolated from 103 COVID-19 survivors 3-5 months post recovery who were classified as having had severe (n = 56; age 53.12 ± 11.30 years), moderate (n = 32; age 52.28 ± 11.43 years) or mild (n = 15; age 49.67 ± 7.30 years) disease and compared with age and sex-matched healthy adults (n = 59; age 50.49 ± 10.68 years). We assessed a broad range of immune cell phenotypes to generate a composite score, IMM-AGE, to determine the degree of immune senescence. We found increased immunesenescence features in severe COVID-19 survivors compared to controls including: a reduced frequency and number of naïve CD4 and CD8 T cells (p < 0.0001); increased frequency of EMRA CD4 (p < 0.003) and CD8 T cells (p < 0.001); a higher frequency (p < 0.0001) and absolute numbers (p < 0.001) of CD28-ve CD57+ve senescent CD4 and CD8 T cells; higher frequency (p < 0.003) and absolute numbers (p < 0.02) of PD-1 expressing exhausted CD8 T cells; a two-fold increase in Th17 polarisation (p < 0.0001); higher frequency of memory B cells (p < 0.001) and increased frequency (p < 0.0001) and numbers (p < 0.001) of CD57+ve senescent NK cells. As a result, the IMM-AGE score was significantly higher in severe COVID-19 survivors than in controls (p < 0.001). Few differences were seen for those with moderate disease and none for mild disease. Regression analysis revealed the only pre-existing variable influencing the IMM-AGE score was South Asian ethnicity ([Formula: see text] = 0.174, p = 0.043), with a major influence being disease severity ([Formula: see text] = 0.188, p = 0.01).

CONCLUSIONS

Our analyses reveal a state of enhanced immune ageing in survivors of severe COVID-19 and suggest this could be related to SARS-Cov-2 infection. Our data support the rationale for trials of anti-immune ageing interventions for improving clinical outcomes in these patients with severe disease.

Age-related Changes in the Adrenal Cortex: Insights and Implications

Aging is characterized by a gradual decline in physiological function. This process affects all organs including the adrenal cortex, which normally functions to produce essential steroid hormones including mineralocorticoids, glucocorticoids, and androgens. With increasing age, features such as reduced adrenal cortex size, altered zonation, and increased myeloid immune cell infiltration substantially alter the structure and function of the adrenal cortex. Many of these hallmark features of adrenal cortex aging occur both in males and females, yet are more enhanced in males. Hormonally, a substantial reduction in adrenal androgens is a key feature of aging, which is accompanied by modest changes in aldosterone and cortisol. These hormonal changes are associated with various pathological consequences including impaired immune responses, decreased bone health, and accelerated age-related diseases. One of the most notable changes with adrenal aging is the increased incidence of adrenal tumors, which is sex dimorphic with a higher prevalence in females. Increased adrenal tumorigenesis with age is likely driven by both an increase in genetic mutations as well as remodeling of the tissue microenvironment. Novel antiaging strategies offer a promising avenue to mitigate adrenal aging and alleviate age-associated pathologies, including adrenal tumors.

Transcranial Electromagnetic Wave Treatment: A Fountain of Healthy Longevity?

Most diseases of older age have as their common denominator a dysfunctional immune system, wherein a low, chronic level of inflammation is present due to an imbalance of pro-inflammatory cytokines over anti-inflammatory cytokines that develops during aging ("inflamm-aging"). A gerotherapeutic that can restore the immune balance to that shared by young/middle-aged adults and many centenarians could reduce the risk of those age-related diseases and increase healthy longevity. In this perspectives paper, we discuss potential longevity interventions that are being evaluated and compare them to a novel gerotherapeutic currently being evaluated in humans-Transcranial Electromagnetic Wave Treatment (TEMT). TEMT is provided non-invasively and safety through a novel bioengineered medical device-the MemorEM-that allows for near complete mobility during in-home treatments. Daily TEMT to mild/moderate Alzheimer's Disease (AD) patients over a 2-month period rebalanced 11 of 12 cytokines in blood back to that of normal aged adults. A very similar TEMT-induced rebalancing of cytokines occurred in the CSF/brain for essentially all seven measurable cytokines. Overall inflammation in both blood and brain was dramatically reduced by TEMT over a 14-27 month period, as measured by C-Reactive Protein. In these same AD patients, a reversal of cognitive impairment was observed at 2 months into treatment, while cognitive decline was stopped over a 2½ year period of TEMT. Since most age-related diseases have the commonality of immune imbalance, it is reasonable to postulate that TEMT could rebalance the immune system in many age-related diseases as it appears to do in AD. We propose that TEMT has the potential to reduce the risk/severity of age-related diseases by rejuvenating the immune system to a younger age, resulting in reduced brain/body inflammation and a substantial increase in healthy longevity.

Multisystem physiological perspective of human frailty and its modulation by physical activity

"Frailty" is a term used to refer to a state characterized by enhanced vulnerability to, and impaired recovery from, stressors compared with a nonfrail state, which is increasingly viewed as a loss of resilience. With increasing life expectancy and the associated rise in years spent with physical frailty, there is a need to understand the clinical and physiological features of frailty and the factors driving it. We describe the clinical definitions of age-related frailty and their limitations in allowing us to understand the pathogenesis of this prevalent condition. Given that age-related frailty manifests in the form of functional declines such as poor balance, falls, and immobility, as an alternative we view frailty from a physiological viewpoint and describe what is known of the organ-based components of frailty, including adiposity, the brain, and neuromuscular, skeletal muscle, immune, and cardiovascular systems, as individual systems and as components in multisystem dysregulation. By doing so we aim to highlight current understanding of the physiological phenotype of frailty and reveal key knowledge gaps and potential mechanistic drivers of the trajectory to frailty. We also review the studies in humans that have intervened with exercise to reduce frailty. We conclude that more longitudinal and interventional clinical studies are required in older adults. Such observational studies should interrogate the progression from a nonfrail to a frail state, assessing individual elements of frailty to produce a deep physiological phenotype of the syndrome. The findings will identify mechanistic drivers of frailty and allow targeted interventions to diminish frailty progression.

Polysaccharide from Flammulina velutipes residues protects mice from Pb poisoning by activating Akt/GSK3β/Nrf-2/HO-1 signaling pathway and modulating gut microbiota

Lead (Pb) can cause damages to the brain, liver, kidney, endocrine and other systems. Flammulina velutipes residues polysaccharide (FVRP) has been reported to exhibit anti-heavy metal toxicity on yeast, but its regulating mechanism is unclear. Therefore, the protective effect and the underlying mechanism of FVRP on Pb-intoxicated mice were investigated. The results showed that FVRP could reduce liver and kidney function indexes, serum inflammatory factor levels, and increase antioxidant enzyme activity of Pb-poisoned mice. FVRP also exhibited a protective effect on histopathological damages in organs of Pb-intoxicated mice. Furthermore, FVRP attenuated Pb-induced kidney injury by inhibiting apoptosis via activating the Akt/GSK3β/Nrf-2/HO-1 signaling pathway. In addition, based on 16 s rRNA and ITS-2 sequencing data, FVRP regulated the imbalance of gut microbiota to alleviate the damage of Pb-poisoned mice by increasing the abundance of beneficial microbiota (Lachnospiraceae, Lactobacillaceae, Saccharomyces and Mycosphaerella) and decreasing the abundance of harmful microbiota (Muribaculaceae and Pleosporaceae). In conclusion, FVRP inhibited kidney injury in Pb-poisoned mice by inhibiting apoptosis via activating Akt/GSK3β/Nrf-2/HO-1 signaling pathway, and regulating gut fungi and gut bacteria. This study not only revealed the role of gut fungi in Pb-toxicity, but also laid a theoretical foundation for FVRP as a natural drug against Pb-toxicity.

Inflammaging as a target for healthy ageing

Life expectancy has been on the rise for the past few decades, but healthy life expectancy has not kept pace, leading to a global burden of age-associated disorders. Advancing age is accompanied by a chronic increase in basal systemic inflammation, termed inflammaging, contributing towards an increased risk of developing chronic diseases in old age. This article reviews the recent literature to formulate hypotheses regarding how age-associated inflammaging plays a crucial role in driving chronic diseases and ill health in older adults. Here, we discuss how non-pharmacological intervention strategies (diet, nutraceutical supplements, phytochemicals, physical activity, microbiome-based therapies) targeting inflammaging restore health in older adults. We also consider alternative existing pharmacological interventions (Caloric restriction mimetics, p38 mitogen-activated protein kinase inhibitors) and explore novel targets (senolytics) aimed at combating inflammaging and optimising the ageing process to increase healthy lifespan.

SOCIAL ENVIRONMENT IMPROVES THE CYTOKINE PROFILE AND LYMPHOPROLIFERATIVE RESPONSE IN CHRONOLOGICALLY OLD AND PREMATURELY AGING MICE

Among the age-associated changes in the immune system, the most evident is the decrease in proliferative responses of lymphocytes to mitogenic stimuli, which is accompanied by the loss of cytokine network homeostasis. Chronic low-grade inflammatory stress, termed as sterile inflammation, is also observed during aging. In chronologically and prematurely aging mice, cohabitation with adult animals for two months favored improvements in several immune functions. This study aimed to determine whether cohabitation could restore several cytokine networks, improve lymphoproliferative responses to mitogens, and diminish sterile inflammation. Chronologically old mice (76±4 weeks) and prematurely aging mice (33±4 weeks) (PAM and TH-HZ) were cohabited with adults (without premature aging) for two months. Subsequently, lymphoproliferation in both basal (unstimulated) conditions and in the presence of mitogenic stimuli lipopolysaccharide A (LPS) or concanavalin A (ConA) was analyzed in cultures of peritoneal leukocytes for 48h. Cytokine secretions (IL-1β, TNF-α, IL-6, IL-10, and IL-17) in these cultures were also evaluated. The results showed that cohabitation restored the levels of these cytokines in old and prematurely aging mice and improved the subsequent lymphoproliferative responses. In addition, this social strategy diminished sterile inflammation and decreased inflammatory stress in unstimulated conditions. Therefore, this strategy seems to be capable of restoring the relevant immune function of lymphocytes and reducing the inflammatory stress, which are the improvements required for an adequate immune response.

Obesity Increases Gene Expression of Markers Associated With Immunosenescence in Obese Middle-Aged Individuals

Recently, it has been argued that obesity leads to a chronic pro-inflammatory state that can accelerate immunosenescence, predisposing to the early acquisition of an immune risk profile and health problems related to immunity in adulthood. In this sense, the present study aimed to verify, in circulating leukocytes, the gene expression of markers related to early immunosenescence associated with obesity and its possible relationships with the physical fitness in obese adults with type 2 diabetes or without associated comorbidities. The sample consisted of middle-aged obese individuals (body mass index (BMI) between 30-35 kg/m²) with type 2 diabetes mellitus (OBD; n = 17) or without associated comorbidity (OB; n = 18), and a control group of eutrophic healthy individuals (BMI: 20 - 25 kg/m²) of same ages (E; n = 18). All groups (OBD, OB and E) performed the functional analyses [muscle strength (1RM) and cardiorespiratory fitness (VO_2max)], anthropometry, body composition (Air Displacement Plethysmograph), blood collections for biochemical (anti-CMV) and molecular (gene expression of leptin, IL-2, IL-4, IL-6, IL-10, TNF-α, PD-1, P16^ink4a, CCR7, CD28 and CD27) analyses of markers related to immunosenescence. Increased gene expression of leptin, IL-2, IL-4, IL-10, TNF-α, PD-1, P16^ink4a, CCR7 and CD27 was found for the OBD and OB groups compared to the E group. Moreover, VO_2max for the OBD and OB groups was significantly lower compared to E. In conclusion, obesity, regardless of associated disease, induces increased gene expression of markers associated with inflammation and immunosenescence in circulating leukocytes in obese middle-aged individuals compared to a eutrophic group of the same age. Additionally, increased adipose tissue and markers of chronic inflammation and immunosenescence were associated to impairments in the cardiorespiratory capacity of obese middle-aged individuals.

Evidence for the Contribution of Gut Microbiota to Age-Related Anabolic Resistance

Globally, people 65 years of age and older are the fastest growing segment of the population. Physiological manifestations of the aging process include undesirable changes in body composition, declines in cardiorespiratory fitness, and reductions in skeletal muscle size and function (i.e., sarcopenia) that are independently associated with mortality. Decrements in muscle protein synthetic responses to anabolic stimuli (i.e., anabolic resistance), such as protein feeding or physical activity, are highly characteristic of the aging skeletal muscle phenotype and play a fundamental role in the development of sarcopenia. A more definitive understanding of the mechanisms underlying this age-associated reduction in anabolic responsiveness will help to guide promyogenic and function promoting therapies. Recent studies have provided evidence in support of a bidirectional gut-muscle axis with implications for aging muscle health. This review will examine how age-related changes in gut microbiota composition may impact anabolic response to protein feeding through adverse changes in protein digestion and amino acid absorption, circulating amino acid availability, anabolic hormone production and responsiveness, and intramuscular anabolic signaling. We conclude by reviewing literature describing lifestyle habits suspected to contribute to age-related changes in the microbiome with the goal of identifying evidence-informed strategies to preserve microbial homeostasis, anabolic sensitivity, and skeletal muscle with advancing age.

How Could We Slow or Reverse the Human Aging Process and Extend the Healthy Life Span with Heterochronous Autologous Hematopoietic Stem Cell Transplantation

The senescence of the immune system contributes considerably to the age-related diseases that are the main causes of death after the age of 65. In this study, we present an appealing option for the prevention of immune senescence and slowing or reversing the aging process, which can be achieved by heterochronous autologous hematopoietic stem cell transplantation (haHSCT), where healthy autologous bone marrow stem cells are collected from donors while young, cryopreserved and stored for a long period, and reinfused at a later time when indicated. After reinfusion and homing, these young HSCs could participate in normal hemato- and immunopoiesis and improve several immune functions by expanding the immune- as well as hematopoietic cell repertoire. Several animal studies have already confirmed the feasibility of this procedure, which extended the longevity of the treated animals. If translated to human medicine, haHSCT could prevent or mitigate age-related immune defects and extend the healthy life span. In this review, we describe the concept of haHSCT, recent studies that confirm its feasibility, and discuss the further research needed to translate this heterochronous methodology.

Function, Oxidative, and Inflammatory Stress Parameters in Immune Cells as Predictive Markers of Lifespan throughout Aging

According to the oxidative-inflammatory theory of aging, there is a link between the function, the oxidative-inflammatory stress state of immune cells, and longevity. However, it is unknown which immune cell parameters can predict lifespan and if there would be any changes in this prediction, depending on the age of the subject. Therefore, a longitudinal study in mice was performed analysing immune function (chemotaxis of macrophages and lymphocytes, phagocytosis of macrophages, natural killer (NK) activity, and lymphoproliferation capacity), antioxidant (catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities as well as reduced glutathione (GSH) concentrations), oxidant (oxidized glutathione (GSSG), superoxide anion, and malondialdehyde (MDA) concentrations), and inflammation-related markers (basal release of IL-1β, IL-6, TNF-α, and IL-10) in peritoneal leukocytes from mice at the adult, mature, old, very old, and long-lived ages (40, 56, 72, 96, and 120 ± 4 weeks of age, respectively). The results reveal that some of the investigated parameters are determinants of longevity at the adult age (lymphoproliferative capacity, lymphocyte chemotaxis, macrophage chemotaxis and phagocytosis, GPx activity, and GSH, MDA, IL-6, TNF-α, and IL-10 concentrations), and therefore, they could be proposed as markers of the rate of aging. However, other parameters are predictive of extreme longevity only at the very old age (NK activity, CAT and GR activities, and IL-6 and IL-1β concentrations), and as such, they could reflect some of the adaptive mechanisms underlying the achievement of high longevity. Nevertheless, although preliminary, the results of the present study provide a new perspective on the use of function, redox, and inflammatory parameters in immune cells as prognostic tools in aging research and represent a novel benchmark for future work aimed at prediction of lifespan.

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.

Updates on Old and Weary Haematopoiesis

Blood formation, or haematopoiesis, originates from haematopoietic stem cells (HSCs), whose functions and maintenance are regulated in both cell- and cell non-autonomous ways. The surroundings of HSCs in the bone marrow create a specific niche or microenvironment where HSCs nest that allows them to retain their unique characteristics and respond rapidly to external stimuli. Ageing is accompanied by reduced regenerative capacity of the organism affecting all systems, due to the progressive decline of stem cell functions. This includes blood and HSCs, which contributes to age-related haematological disorders, anaemia, and immunosenescence, among others. Furthermore, chronological ageing is characterised by myeloid and platelet HSC skewing, inflammageing, and expanded clonal haematopoiesis, which may be the result of the accumulation of preleukaemic lesions in HSCs. Intriguingly, haematological malignancies such as acute myeloid leukaemia have a high incidence among elderly patients, yet not all individuals with clonal haematopoiesis develop leukaemias. Here, we discuss recent work on these aspects, their potential underlying molecular mechanisms, and the first cues linking age-related changes in the HSC niche to poor HSC maintenance. Future work is needed for a better understanding of haematopoiesis during ageing. This field may open new avenues for HSC rejuvenation and therapeutic strategies in the elderly.

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.

An Appropriate Modulation of Lymphoproliferative Response and Cytokine Release as Possible Contributors to Longevity

The decrease in the proliferative response of lymphocytes is one of the most evident among the age-related changes of the immune system. This has been linked to a higher risk of mortality in both humans and experimental animals. However, long-lived individuals, in spite of optimally maintaining most of the functions of the immune system, also seem to show an impaired proliferative response. Thus, it was hypothesized that these individuals may have distinct evolution times in this proliferation and a different modulatory capacity through their cytokine release profiles. An individualized longitudinal study was performed on female ICR-CD1 mice, starting at the adult age (40 weeks old), analyzing the proliferation of peritoneal leukocytes at different ages in both basal conditions and in the presence of the mitogen Concanavalin A, for 4, 24 and 48 h of culture. The cytokine secretions (IL-2, IL-17, IL-1β, IL-6, TNF-α and IL-10) in the same cultures were also studied. Long-lived mice show a high proliferative capacity after short incubation times and, despite experiencing a functional decline when they are old, are able to compensate this decrease with an appropriate modulation of the lymphoproliferative response and cytokine release. This could explain their elevated resistance to infections and high longevity.

Identification of a fourth ancient member of the IL-3/IL-5/GM-CSF cytokine family, KK34, in many mammals

The related cytokine genes IL-3, IL-5 and GM-CSF map to the (extended) TH2 cytokine locus of the mammalian genome. For chicken an additional related cytokine gene, KK34, was reported downstream of the IL-3 plus GM-CSF cluster, but hitherto it was believed that mammalian genomes lack this gene. However, the present study identifies an intact orthologue of chicken KK34 gene in many mammals like cattle and pig, while remnants of KK34 can be found in human and mouse. Bovine KK34 was found to be transcribed, and its recombinant protein could induce STAT5 phosphorylation and proliferation of lymphocytes upon incubation with bovine PBMCs. This concludes that KK34 is a fourth functional cytokine of the IL-3/IL-5/GM-CSF/KK34-family (alias IL-5 family) in mammals. While analyzing KK34, the present study also made new identifications of cytokine genes in the extended TH2 cytokine loci for reptiles, birds and marsupials. This includes a hitherto unknown cytokine gene in birds and reptiles which we designated "IL-5famE". Other newly identified genes are KK34, GM-CSF(-like), IL-5, and IL-13 in reptiles, and IL-3 in marsupials.

Conservation of pro-longevity genes among mammals

Genes which confer a relative longevity advantage may be regulated at the level of transcription or translation. Alternatively, pro-longevity genes may mediate their effects at the level of protein structure-functional relationships that are beneficially optimized in long-lived species. Longevity associated genes (LAGs) may be operationally defined as genes that confer beneficial effects and are relatively more conserved among long-lived species. Global and local protein sequence alignments of over 10,000 genes across at least 30 mammalian species were examined to identify LAGs. Known LAGs, including growth hormone receptor (GHR), and breast cancer 1, early onset (BRCA1), have strong associations with maximum lifespan by our analysis. Several common categories of protein function were observed among genes ranked with the strongest associations with MLS identified by all regression models. These genes included those that function in the immune system, cell cycle regulation, and DNA damage response. We provide a ranking of genes with the strongest associations with species maximum lifespan (MLS) by several phylogenetic generalized least squares regression models, including adjustment for confounding variables such as body weight and gestation length.

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.

Peritoneal exudate cells from long-lived rats exhibit increased IL-10/IL-1β expression ratio and preserved NO/urea ratio following LPS-stimulation in vitro

In humans, usual aging, differently from successful aging, is associated with deregulation of proinflammatory/anti-inflammatory cytokine balance. The corresponding data from rat studies are limited. Therefore, we examined (i) cytokine messenger RNA (mRNA) profile of fresh peritoneal cells from 6- (adult), 24- (old), and 31-month-old (long-lived) AO rats and (ii) proinflammatory (IL-1β and IL-6) and anti-inflammatory (IL-10) cytokine, NO, and urea production in their LPS-stimulated cultures. Comparing with adult rats, cells from old ones expressed lower amount of TNF-α and IL-6 mRNAs, but greater amount of IL-1β mRNA. On the other hand, cells from long-lived rats exhibited a dramatic increase in IL-10 mRNA expression followed by diminished TNF-α and IL-6 mRNA expression, and comparable expression of IL-1β mRNA relative to adult rats. Consequently, IL-10/IL-1β mRNA ratio was greater in cells from long-lived rats than in adult and old rats. In LPS-stimulated peritoneal cell cultures (contained ≥95 % macrophages) from old rats, concentration of common proinflammatory cytokines was higher than in those from adult rats. Comparing with adult and old rats, in LPS-stimulated macrophage cultures from long-lived rats, TNF-α and IL-6 concentrations were lower; IL-1β concentration was comparable or greater (in respect to adult rats), whereas that of IL-10 was strikingly higher. Consistently, in macrophage cultures from long-lived rats, NO (iNOS activity marker)/urea (arginase activity marker) ratio was less and not different from that in old and adult rats, respectively. The study suggests that macrophages from long-lived rats, differently from those of old ones, have substantial ability to limit proinflammatory mediator production, which may contribute to their longevity.

Aging oppositely affects TNF-α and IL-10 production by macrophages from different rat strains

Altered functions of macrophages with aging contribute to impairment of both innate and adaptive immunity in the elderly. The present study aimed to examine strain specificity of age-related changes in the phenotypic and functional characteristics of macrophages from DA and AO rats, which differ in average life span. Resident peritoneal macrophages from young (10-12 weeks old) and aged (98-104 weeks old) rats were tested for: (a) the surface expression of TLR4 and CD14; (b) the basal and LPS-induced production of TNF-α and IL-10; and (c) the basal and LPS-induced activity of iNOS and arginase, by measuring the levels of NO and urea, respectively, in the culture supernatants. Aging elevated TLR4 macrophage surface density in rats of both strains. Conversely, the age-related decrease in the surface density of CD14 co-receptor was detected only on macrophages from aged DA rats. Accordingly, with aging in DA rats, contrary to AO rats, upon LPS-stimulation both TNF-α and IL-10 levels decreased in culture supernatants. However, in rats of both strains TNF-α stimulation index (LPS-induced over basal production) remained stable with aging, but it was significantly greater in AO rats. Furthermore, with aging, IL-10 stimulation index decreased and increased in DA and AO rats, respectively. Age-related shift in urea stimulation index complied with the changes of IL-10 stimulation index during aging. In conclusion, the study suggests that the preserved ability of macrophages from aged AO rats to synthesize not only proinflammatory TNF-α, but also immunoregulatory IL-10 cytokine most likely contributes to their longer average life compared with DA rats.

Aging and its Impact on Innate Immunity and Inflammation: Implications for Periodontitis

The elderly exhibit increased susceptibility to a number of inflammatory or degenerative pathologies. Aging is similarly thought to be associated with increased prevalence and severity of periodontitis, although the underlying causes are poorly understood. Among the plausible mechanisms whereby aging could contribute to increased susceptibility to periodontitis are age-dependent alterations in the innate immune and inflammatory status of the host. This hypothesis is supported by studies in humans and animal models outlined in this Review. Indeed, innate immune cells isolated from elderly subjects exhibit age-related cell-intrinsic defects that could predispose the elderly to deregulated immune and inflammatory responses. Moreover, the investigation of age-related alterations in the tissue environment where recruited inflammatory cells ultimately function could provide complementary, if not better, insights into the impact of aging on periodontitis. Integrative approaches combining in vitro and in vivo mechanistic models are underway and can potentially contribute to targeted molecular therapies that can reverse or mitigate the effects of aging on periodontitis and other inflammatory diseases.

An age-related numerical and functional deficit in CD19(+) CD24(hi) CD38(hi) B cells is associated with an increase in systemic autoimmunity

Autoimmunity increases with aging indicative of reduced immune tolerance, but the mechanisms involved are poorly defined. In recent years, subsets of B cells with immunoregulatory properties have been identified in murine models of autoimmune disorders, and these cells downregulate immune responses via secretion of IL10. In humans, immature transitional B cells with a CD19(+) CD24(hi) CD38(hi) phenotype have been reported to regulate immune responses via IL10 production. We found the frequency and numbers of CD19(+) CD24(hi) CD38(hi) cells were reduced in the PBMC pool with age. IL10 expression and secretion following activation via either CD40, or Toll-like receptors was also impaired in CD19(+) CD24(hi) CD38(hi) B cells from healthy older donors. When investigating the mechanisms involved, we found that CD19(+) CD24(hi) CD38(hi) B-cell function was compromised by age-related effects on both T cells and B cells: specifically, CD40 ligand expression was lower in CD4 T cells from older donors following CD3 stimulation, and signalling through CD40 was impaired in CD19(+) CD24(hi) CD38(hi) B cells from elders as evidenced by reduced phosphorylation (Y705) and activation of STAT3. However, there was no age-associated change in expression of costimulatory molecules CD80 and CD86 on CD19(+) CD24(hi) CD38(hi) cells, suggesting IL10-dependent immune suppression is impaired, but contact-dependent suppressive capacity is intact with age. Finally, we found a negative correlation between CD19(+) CD24(hi) CD38(hi) B-cell IL10 production and autoantibody (Rheumatoid factor) levels in older adults. We therefore propose that an age-related decline in CD19(+) CD24(hi) CD38(hi) B cell number and function may contribute towards the increased autoimmunity and reduced immune tolerance seen with aging.

Neutrophil heterogeneity in health and disease: a revitalized avenue in inflammation and immunity

Leucocytes form the principal cellular components of immunity and inflammation, existing as multiple subsets defined by distinct phenotypic and functional profiles. To date, this has most notably been documented for lymphocytes and monocytes. In contrast, as neutrophils are traditionally considered, to be short-lived, terminally differentiated cells that do not re-circulate, the potential existence of distinct neutrophil subsets with functional and phenotypic heterogeneity has not been widely considered or explored. A growing body of evidence is now challenging this scenario, and there is significant evidence for the existence of different neutrophil subsets under both physiological and pathological conditions. This review will summarize the key findings that have triggered a renewed interest in neutrophil phenotypic changes, both in terms of functional implications and consequences within disease models. Special emphasis will be placed on the potential pro- and anti-inflammatory roles of neutrophil subsets, as indicated by the recent works in models of ischaemia–reperfusion injury, trauma, cancer and sepsis.

The effects of weight cycling on lifespan in male C57BL/6J mice

OBJECTIVE

With the increasing rates of obesity, many people diet in an attempt to lose weight. As weight loss is seldom maintained in a single effort, weight cycling is a common occurrence. Unfortunately, reports from clinical studies that have attempted to determine the effect of weight cycling on mortality are in disagreement, and to date, no controlled animal study has been performed to assess the impact of weight cycling on longevity. Therefore, our objective was to determine whether weight cycling altered lifespan in mice that experienced repeated weight gain and weight loss throughout their lives.

METHODS

Male C57BL/6J mice were placed on one of three lifelong diets: a low-fat (LF) diet, a high-fat (HF) diet or a cycled diet in which the mice alternated between 4 weeks on the LF diet and 4 weeks on the HF diet. Body weight, body composition, several blood parameters and lifespan were assessed.

RESULTS

Cycling between the HF and LF diet resulted in large fluctuations in body weight and fat mass. These gains and losses corresponded to significant increases and decreases, respectively, in leptin, resistin, GIP, IGF-1, glucose, insulin and glucose tolerance. Surprisingly, weight cycled mice had no significant difference in lifespan (801±45 days) as compared to LF-fed controls (828±74 days), despite being overweight and eating a HF diet for half of their lives. In contrast, the HF-fed group experienced a significant decrease in lifespan (544±73 days) compared with LF-fed controls and cycled mice.

CONCLUSIONS

This is the first controlled mouse study to demonstrate the effect of lifelong weight cycling on longevity. The act of repeatedly gaining and losing weight, in itself, did not decrease lifespan and was more beneficial than remaining obese.

The aging immune system and its relationship with cancer

The incidence of most common cancers increases with age. This occurs in association with, and is possibly caused by a decline in immune function, termed immune senescence. Although the size of the T-cell compartment is quantitatively maintained into older age, several deleterious changes (including significant changes to T-cell subsets) occur over time that significantly impair immunity. This article highlights some of the recent findings regarding the aging immune system, with an emphasis on the T-cell compartment and its role in cancer.

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.

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.