Immunological biomarkers of ageing in man: changes in both innate and adaptive immunity are associated with health and longevity

Does biological age mediate the relationship between childhood adversity and depression? Insights from the Detroit Neighborhood Health Study

The link between childhood adversity and adulthood depression is well-established; however, the underlying mechanisms are still being explored. Recent research suggests biological age may mediate the relationship between childhood adversity and depression in later life. This study examines if biological age mediates the relationship between childhood adversity and depression symptoms using an expanded set of biological age measures in an urban population-based cohort. Data from waves 1-3 of the Detroit Neighborhood Health Study (DNHS) were used in this analysis. Questions about abuse during childhood were coded to form a childhood adversity score similar to the Adverse Childhood Experience measure. Multiple dimensions of biological age, defined as latent variables, were considered, including systemic biological age (GrimAge, PhenoAge), epigenetic age (Horvath, SkinBlood), and immune age (cytomegalovirus, herpes simplex virus type 1, C-reactive protein, interleukin-6). Depression symptoms, modeled as a latent variable, were captured through the Patient Health Questionnaire-9 (PHQ-9). Models were adjusted for age, gender, race, parent education, and past depressive symptoms. Total and direct effects of childhood adversity on depression symptoms and indirect effects mediated by biological age were estimated. For total and direct effects, we observed a dose-dependent relationship between cumulative childhood adversity and depression symptoms, with emotional abuse being particularly influential. However, contrary to prior studies, in this sample, we found few direct effects of childhood adversity on biological age or biological age on depression symptoms and no evidence of mediation through the measures of biological age considered in this study. Further research is needed to understand how childhood maltreatment experiences are embodied to influence health and wellness.

Maladaptive Immune Activation in Age-Related Decline of Muscle Function

Age-related changes in immune competency and inflammation play a role in the decline of physical function. In this review of the conference on Function-Promoting Therapies held in March 2022, we discuss the biology of aging and geroscience with an emphasis on decline in physical function and the role of age-related changes in immune competence and inflammation. More recent studies in skeletal muscle and aging highlighting a crosstalk between skeletal muscle, neuromuscular feedback, and immune cell subsets are also discussed. The value of strategies targeting specific pathways that affect skeletal muscle and more systems-wide approaches that provide benefits in muscle homeostasis with aging are underscored. Goals in clinical trial design and the need for incorporating differences in life history when interpreting results from these intervention strategies are important. Where applicable, references are made to papers presented at the conference. We conclude by underscoring the need to incorporate age-related immune competency and inflammation when interpreting results from interventions that target specific pathways predicted to promote skeletal muscle function and tissue homeostasis.

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.

Age-associated phenotypic imbalance in TCD4 and TCD8 cell subsets: comparison between healthy aged, smokers, COPD patients and young adults

Background

COPD is associated with an abnormal lung immune response that leads to tissue damage and remodeling of the lung, but also to systemic effects that compromise immune responses. Cigarette smoking also impacts on innate and adaptative immune responses, exerting dual, pro- and anti-inflammatory effects. Previously, we showed that COPD patients presented accelerated telomere shortening and decreased telomerase activity, while, paradoxically, cigarette-smokers exhibited preserved telomerase activity and slower rate of telomere shortening.

Results

Here, we evaluated the naive, CM, EM and TEMRA subsets of TCD4 and TCD8 cells according to the expression of CCR7/CD45RA. We compared age-matched COPD patients, cigarette-smokers without clinical-laboratory evidence of pulmonary compromise, and healthy individuals. They were additionally compared with a group of young adults. For each subset we analysed the expression of markers associated with late differentiation, senescence and exhaustion (CD27/CD28/CD57/KLRG1/PD1). We show that COPD patients presented a drastically reduced naive cells pool, and, paradoxically, increased fractions of naive cells expressing late differentiation, senescence or exhaustion markers, likely impacting on their immunocompetence. Pronounced phenotypic alterations were also evidenced in their three memory T-cell subsets compared with the other aged and young groups, suggesting an also dysfunctional memory pool. Surprisingly, our smokers showed a profile closer to the Healthy aged than COPD patients. They exhibited the usual age-associated shift of naive to EM TCD4 and TCD8 cells, but not to CM or TEMRA T-cells. Nonetheless, their naive T-cells phenotypes were in general similar to those of the Youngs and Healthy aged, suggesting a rather phenotypically preserved subset, while the memory T-cells exhibited increased proportions of cells with the late-differentiation or senescence/exhaustion markers as in the Healthy aged.

Conclusion

Our study extends previous findings by showing that COPD patients have cells expressing a full range of late differentiated, senescent or exhausted phenotypes encompassing all TCD4 and TCD8 subsets, consistent with a premature immunosenescence phenotype. Surprisingly, the smokers group’s results suggest that moderate to heavy chronic cigarette smoking did not accelerate the pace of immunosenescence as compared with the Healthy aged.

A Machine Learning-Based Aging Measure Among Middle-Aged and Older Chinese Adults: The China Health and Retirement Longitudinal Study

Objective: Biological age (BA) has been accepted as a more accurate proxy of aging than chronological age (CA). This study aimed to use machine learning (ML) algorithms to estimate BA in the Chinese population. Materials and methods: We used data from 9,771 middle-aged and older Chinese adults (≥45 years) in the 2011/2012 wave of the China Health and Retirement Longitudinal Study and followed until 2018. We used several ML algorithms (e.g., Gradient Boosting Regressor, Random Forest, CatBoost Regressor, and Support Vector Machine) to develop new measures of biological aging (ML-BAs) based on physiological biomarkers. R-squared value and mean absolute error (MAE) were used to determine the optimal performance of these ML-BAs. We used logistic regression models to examine the associations of the best ML-BA and a conventional aging measure-Klemera and Doubal method-BA (KDM-BA) we previously developed-with physical disability and mortality, respectively. Results: The Gradient Boosting Regression model performed the best, resulting in an ML-BA with an R-squared value of 0.270 and an MAE of 6.519. This ML-BA was significantly associated with disability in basic activities of daily living, instrumental activities of daily living, lower extremity mobility, and upper extremity mobility, and mortality, with odds ratios ranging from 1 to 7% (per 1-year increment in ML-BA, all P < 0.001), independent of CA. These associations were generally comparable to that of KDM-BA. Conclusion: This study provides a valid ML-based measure of biological aging for middle-aged and older Chinese adults. These findings support the application of ML in geroscience research and may help facilitate preventive and geroprotector intervention studies.

Systematic review on the effects of physical exercise on cellular immunosenescence-related markers - An update

Immunosenescence is a remodeling of the immune system occurring with aging that leads to an increased susceptibility to auto-immunity, infections and reduced vaccination response. A growing consensus supports the view that physical exercise may counteract immunosenescence and improve the immune response. Unfortunately, evidence regarding the effects of exercise on markers of cellular immunosenescence lacked uniformity at the time of an extensive literature review in 2016. Moreover, exercise-induced effects in older adults were underrepresented compared to young adults or completely lacking, such as for senescent T-cells and apoptosis of T-lymphocytes. The aim of this systematic literature study was to collect and appraise newly available data regarding exercise-induced changes on immunosenescence-related markers of immune cells and compare this against data that was already available in 2016. Systematic reviewing of newly available data in the field of exercise immunology provides additional evidence for the effect of exercise on immunosenescence-related cellular markers. Importantly, this review provides evidence for the effect of long-term exercise on senescent T-lymphocytes in older adults. Additionally, newly retrieved evidence shows an acute exercise-induced mobilization of naïve and memory cells in older adults. In general, data regarding long-term exercise-induced effects in older adults remain scarce. Noteworthy was the high number of articles describing exercise-induced effects on regulatory T-cells. However exercise-induced effects on this cell type are still inconclusive as some articles reported an exercise-induced up- or downregulation, while others reported no effects at all. Numerous studies on Natural Killer cell counts did not provide uniformity among data that was already available. Recent data regarding dendritic cells mostly described an increase after exercise. Overall, our literature update highlights the major influence of the type and intensity of exercise on immunosenescence-related markers, especially in older adults.

Vitamin D and Exercise Are Major Determinants of Natural Killer Cell Activity, Which Is Age- and Gender-Specific

Background

The coronavirus-19 disease (COVID-19) pandemic reminds us of the importance of immune function, even in immunologically normal individuals. Multiple lifestyle factors are known to influence the immune function.

Objective

The aim was to investigate the association between NK cell activity (NKA) and multiple factors including vitamin D, physical exercise, age, and gender.

Methods

This was a cross-sectional association study using health check-up and NKA data of 2,095 subjects collected from 2016 to 2018 in a health check-up center in the Republic of Korea. NKA was measured using the interferon-γ (IFN-γ) stimulation method. The association of NKA with 25-(OH)-vitamin D (25(OH)D) and other factors was investigated by multiple logistic regression analysis.

Results

The average age of subjects was 48.8 ± 11.6 years (52.9% of subjects were female). Among 2,095 subjects, 1,427 had normal NKA (NKA ≥ 500 pg IFN-γ/mL), while 506 had low NKA (100 ≤ NKA < 500 pg/mL), and 162 subjects had very low NKA (NKA < 100 pg/mL). Compared to men with low 25(OH)D serum level (< 20 ng/mL), vitamin D replete men (30–39.9 ng/mL) had significantly lower risk of very low NKA (OR: 0.358; 95% CI: 0.138, 0.929; P = 0.035). In women, both low exercise (OR: 0.529; 95% CI: 0.299, 0.939; P = 0.030) and medium to high exercise (OR: 0.522; 95% CI: 0.277, 0.981; P = 0.043) decreased the risk compared to lack of physical exercise. Interestingly, in men and women older than 60 years, physical exercise significantly decreased the risk. Older-age was associated with increased risk of very low NKA in men, but not in women.

Conclusion

Physical exercise and vitamin D were associated with NKA in a gender- and age-dependent manner. Age was a major risk factor of very low NKA in men but not in women.

Immune Function, Oxidative, and Inflammatory Markers in Centenarians as Potential Predictors of Survival and Indicators of Recovery After Hospital Admission

Several parameters of immune function, oxidative, and inflammatory stresses have been proposed as markers of health and predictors of longevity and mortality. However, it is unknown if any of these parameters can be used as predictors of survival in centenarians. Therefore, in a group of 27 centenarians, at the time of admission to the Clinical Hospital of Madrid, a series of immune function, antioxidant, oxidant, and inflammatory parameters were studied. Some centenarians survived and others did not, thus establishing two groups, "survivors" (n = 9) and "nonsurvivors" (n = 18). The results show that surviving centenarians display higher neutrophil chemotaxis and microbicidal capacity, natural killer activity, lymphoproliferation, glutathione reductase activity, and basal interleukin-10 release. Moreover, lower neutrophil and lymphocyte adherence, superoxide anion and malondialdehyde concentrations, and basal release of tumor necrosis factor α are also reported. The odds ratios for survival for these parameters were also calculated, with the highest odds ratios being the lymphoproliferative capacity and the ex vivo basal and stimulated release of interleukin-6 from mononuclear cells (odds ratio = 136.00). Therefore, these parameters have the potential to be used in the clinical setting as predictors of survival in centenarians. In the survivors group, the same parameters were also analyzed after 3 months. Because survivors showed an increase in neutrophil and lymphocyte chemotaxis capacity during the recovery period, reaching similar values to those observed in healthy centenarians, these parameters could be proposed as indicators of recovery.

Susceptibility of aging mice to listeriosis: Role of anti-inflammatory responses with enhanced Treg-cell expression of CD39/CD73 and Th-17 cells

Foodborne Listeria monocytogenes (Lm) causes serious illness and death in immunosuppressed hosts, including the elderly population. We investigated Lm susceptibility and inflammatory cytokines in geriatric mice. Young-adult and old mice were gavaged with a Lm strain Lmo-InlA^m. Tissues were assayed for Lm burden and splenocytes were analyzed for Th1/Th2/Th17/Treg responses and expression of CD39 and CD73. Old Lm-infected mice lost body-weight dose-dependently, had higher Lm colonization, and showed higher inflammatory responses than Lm-infected young-adult mice. After infection, IL-17 levels increased significantly in old mice whereas IFN-γ levels were unchanged. Levels of IL-10 and Treg cells were increased in infected old mice as compared to infected young-adult mice. Age-dependent enhanced expression of CD39/CD73 was observed in purified Treg prior to infection, suggesting increased baseline adenosine production in old mice. Lm lysate-treated splenocytes from older mice produced significantly higher levels of IL-10, IL17, and IL-1β, produced less IFN-γ and IL-2, and proliferated less than splenocytes from young-adult mice. Data suggests that older mice maybe more susceptible to Lm infection due to an imbalance of Th cell responses with disproportionate and persistent anti-inflammatory responses. Lm infection enhanced differentiation of proinflammatory Th17 cells, which may also exacerbate pathological responses during listeriosis.

Efficacy of Phellinus linteus (sanghuang) extract for improving immune functions: Study protocol for a randomized, double-blinded, placebo-controlled pilot trial

BACKGROUND

With the increase in the prevalence of chronic diseases, enhancing immunity has become an important challenge. Health functional foods, such as Phellitus linteus (PL), are known to improve immune function. In previous laboratory studies, it has been reported that PL has anticancer activities. In this study, we will evaluate if PL improves immune functions in adults with reduced immunity and identify its effects on immunity factors.

METHODS

This study will be a single-center, randomized, double-blinded, and placebo-controlled trial. Study participants will be randomly allocated to 3 experimental groups: those taking PL 1000 mg, PL 2000 mg, or placebo. Total duration of the clinical trial will be 8 to 10 weeks. Study participants will have follow-up visits every 4 weeks and the effect and safety will be assessed at the second and third visits. All participants will be asked to maintain a dosage schedule for this protocol. The primary outcome will be natural killer (NK) cell activity and the secondary outcomes will include peripheral white blood cell (WBC) count; levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and interleukin (IL)-1β, IL-2, IL-6, and IL-12 to assess autoimmune reactivity; and levels of immunoglobulin (Ig)G1, IgG2, and Immunoglobulin M (IgM) to assess allergic activity. Repeated measure analysis will be used to measure primary efficacy based on full analysis set.

DISCUSSION

This study has limited inclusion and exclusion criteria and a well-controlled intervention. It will be the first randomized controlled trial to assess the efficacy and safety of PL in adults with reduced immunity. This study will provide insights into the mechanisms underlying the immune-stimulating effects of PL and lay the groundwork for further studies.

Cellular aging over 13 years associated with incident antinuclear antibody positivity in the Baltimore Longitudinal Study of Aging

Age-associated increases in antinuclear antibodies (ANA) in the general population are commonly noted but the mechanisms underlying this observation are unclear. This study aims to evaluate whether shorter peripheral blood mononuclear cell (PBMC) telomere length, a marker of more advanced biological age, is associated with ANA positivity prevalence and incidence in middle and older aged autoimmune disease-free individuals from the Baltimore Longitudinal Study of Aging (BLSA). Telomere length was measured by Southern Blot and categorized into tertiles. ANA was measured in a 1:80 and a 1:160 dilution of sera by immunofluorescence using HEp-2 cells (seropositive = 3 or 4). Multiple logistic regression was used to estimate the odds ratios and 95% confidence intervals of ANA positivity comparing the shorter tertiles of telomere length to the longest tertile for two cross-sectional points in time and then longitudinally to assess the association between shorter telomere length and incident ANA positivity. Cross-sectional analyses were adjusted for sex, race and BMI (N = 368 baseline, N = 370 follow-up) and longitudinal analyses were adjusted for sex, race, BMI and time between baseline and follow-up (N = 246). No statistically significant cross-sectional associations were observed at baseline or follow-up. Among those where ANA negative at baseline, individuals with shorter telomeres were more likely to be ANA positive at follow-up, an average 13 years later. Individuals with short telomeres at both time periods were more likely to be ANA positive. Findings suggest that ANA positivity in the general population may be indicative of immune dysfunction resulting from advanced cellular aging processes.

Gut microbes, ageing & organ function: a chameleon in modern biology?

All species, including humans, are cohabited by a myriad of microbial species, which massively influences body function in a diet‐, exercise‐ and age‐dependent manner. The microbiome composition differs between individuals, partly due to the polymorphic immune system, as well as the environment, making the microbe–host interplay unique in each one of us. Ageing is a gradual loss of function in part due to reduced repair mechanisms and accumulation of tissue damage through mechanisms largely unknown. Accumulating evidence suggests that our indigenous microbes, a known major regulator of human physiology, are also connected to regulate the ageing process through signalling pathways and metabolites though the biological mechanisms are unknown. At an ageing meeting in Singapore in 2018, investigators discussed the current understanding of microbe regulation and its impact on healthy ageing. This review summarizes the highlights from the meeting and conveys some of the new ideas that emerged around gut microbes and the biology of ageing. While highly speculative, an idea emerged in which gut microbes constantly respond and evolve to environmental cues, as part of an ageing process, thus serving as a second messenger to support and attenuate organ decline in a diet‐, gender‐ and age‐dependent manner.

When will my mouse die? Life span prediction based on immune function, redox and behavioural parameters in female mice at the adult age

The identification of predictive markers of life span would help to unravel the underlying mechanisms influencing ageing and longevity. For this aim, 30 variables including immune functions, inflammatory-oxidative stress state and behavioural characteristics were investigated in ICR-CD1 female mice at the adult age (N = 38). Mice were monitored individually until they died and individual life spans were registered. Multiple linear regression was carried out to construct an Immunity model (adjusted R² = 75.8%) comprising Macrophage chemotaxis and phagocytosis and Lymphoproliferation capacity, a Redox model (adjusted R² = 84.4%) involving Reduced Glutathione and Malondialdehyde concentrations and Glutathione Peroxidase activity and a Behavioural model (adjusted R² = 79.8%) comprising Internal Locomotion and Time spent in open arms indices. In addition, a Combined model (adjusted R² = 92.4%) and an Immunity-Redox model (adjusted R² = 88.7%) were also constructed by combining the above-mentioned selected variables. The models were also cross-validated using two different sets of female mice (N = 30; N = 40). Correlation between predicted and observed life span was 0.849 (P < 0.000) for the Immunity model, 0.691 (P < 0.000) for the Redox, 0.662 (P < 0.000) for the Behavioural and 0.840 (P < 0.000) for the Immunity-Redox model. Thus, these results provide a new perspective on the use of immune function, redox and behavioural markers as prognostic tools in ageing research.

Enduring Challenge of Latent Tuberculosis in Older Nursing Home Residents: A Brief Review

Tuberculosis (TB) kills almost 4,000 people a day and is competing with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) as the most deadly infectious disease in the world. The gold standards of detection and management of latent tuberculosis infection (LTBI) have not been successful in complete eradication of the disease. Current screening modalities of TB include tuberculin skin testing (TST) and/or interferon-γ release assay (IGRA). However, these screening tests have been heavily studied in healthy populations but not in the elderly who are more likely to have multiple risk factors for progression to active TB from LTBI. The largest population that is harboring LTBI is the elderly, specifically those residing in nursing homes. Yet, unfortunately, guidelines for standards of detection and treatment for this specific group are lacking. In this review, we look at TST versus IGRA screening for LTBI in the elderly living in nursing homes. We review a cross-sectional study done at Staten Island University Hospital, and several other assessments of the sensitivity and accuracy of both screening tools. Furthermore, this review looks at the appropriateness of current LTBI treatment and prophylaxis in elderly patients residing in close quarters. The reviews point to the superiority of IGRA testing in the elderly for screening LTBI. The IGRA has been shown to be more sensitive to the detection of LTBI than TST. Additionally, medical complexities that the elderly population possesses may present challenges and resistance to standard treatments of LTBI. It is recommended via the literature that the addition of vitamin D, or alternative therapies (e.g. rifampin) could produce better outcomes for elderly patients with LTBI than the current 9 months of isoniazid (INH). As the older adults represent the fastest growing segment of our population and the largest LTBI reservoir in the USA, revisiting screening and treatment of LTBI in the elderly living in nursing homes may prove to lead to a path of TB eradication once and for all.

Aging, Melatonin, and the Pro- and Anti-Inflammatory Networks

Aging and various age-related diseases are associated with reductions in melatonin secretion, proinflammatory changes in the immune system, a deteriorating circadian system, and reductions in sirtuin-1 (SIRT1) activity. In non-tumor cells, several effects of melatonin are abolished by inhibiting SIRT1, indicating mediation by SIRT1. Melatonin is, in addition to its circadian and antioxidant roles, an immune stimulatory agent. However, it can act as either a pro- or anti-inflammatory regulator in a context-dependent way. Melatonin can stimulate the release of proinflammatory cytokines and other mediators, but also, under different conditions, it can suppress inflammation-promoting processes such as NO release, activation of cyclooxygenase-2, inflammasome NLRP3, gasdermin D, toll-like receptor-4 and mTOR signaling, and cytokine release by SASP (senescence-associated secretory phenotype), and amyloid-β toxicity. It also activates processes in an anti-inflammatory network, in which SIRT1 activation, upregulation of Nrf2 and downregulation of NF-κB, and release of the anti-inflammatory cytokines IL-4 and IL-10 are involved. A perhaps crucial action may be the promotion of macrophage or microglia polarization in favor of the anti-inflammatory phenotype M2. In addition, many factors of the pro- and anti-inflammatory networks are subject to regulation by microRNAs that either target mRNAs of the respective factors or upregulate them by targeting mRNAs of their inhibitor proteins.

Lymphoproliferation Impairment and Oxidative Stress in Blood Cells from Early Parkinson's Disease Patients

In Parkinson’s Disease (PD), the peripheral changes in the functional capacity and redox state of immune cells has been scarcely investigated, especially in the early PD stages. Aging is a risk factor for PD, and the age-related impairment of the immune system, based on a chronic-oxidative stress situation, is involved in the rate of aging. We analyzed several functions in isolated peripheral blood neutrophils and mononuclear cells from PD stage 2 patients, and compared the results to those in healthy elderly and adult controls. Several oxidative stress and damage parameters were studied in whole blood cells. The results showed an impairment of the lymphoproliferative response in stimulated conditions in the PD patients compared with age-matched controls, who also showed typical immunosenescence in comparison with adult individuals. Higher oxidative stress and damage were observed in whole blood cells from PD patients (lower glutathione peroxidase activity, and higher oxidized glutathione and malondialdehyde contents). Our results suggest an accelerated immunosenescence in PD stage 2, and that several of the parameters studied could be appropriate peripheral biomarkers in the early stages of PD.

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.

Melatonin and inflammation-Story of a double-edged blade

Melatonin is an immune modulator that displays both pro- and anti-inflammatory properties. Proinflammatory actions, which are well documented by many studies in isolated cells or leukocyte-derived cell lines, can be assumed to enhance the resistance against pathogens. However, they can be detrimental in autoimmune diseases. Anti-inflammatory actions are of particular medicinal interest, because they are observed in high-grade inflammation such as sepsis, ischemia/reperfusion, and brain injury, and also in low-grade inflammation during aging and in neurodegenerative diseases. The mechanisms contributing to anti-inflammatory effects are manifold and comprise various pathways of secondary signaling. These include numerous antioxidant effects, downregulation of inducible and inhibition of neuronal NO synthases, downregulation of cyclooxygenase-2, inhibition of high-mobility group box-1 signaling and toll-like receptor-4 activation, prevention of inflammasome NLRP3 activation, inhibition of NF-κB activation and upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2). These effects are also reflected by downregulation of proinflammatory and upregulation of anti-inflammatory cytokines. Proinflammatory actions of amyloid-β peptides are reduced by enhancing α-secretase and inhibition of β- and γ-secretases. A particular role in melatonin's actions seems to be associated with the upregulation of sirtuin-1 (SIRT1), which shares various effects known from melatonin and additionally interferes with the signaling by the mechanistic target of rapamycin (mTOR) and Notch, and reduces the expression of the proinflammatory lncRNA-CCL2. The conclusion on a partial mediation by SIRT1 is supported by repeatedly observed inhibitions of melatonin effects by sirtuin inhibitors or knockdown.

The role of melatonin, a multitasking molecule, in retarding the processes of ageing

Biological ageing is generally accompanied by a gradual loss of cellular functions and physiological integrity of organ systems, the consequential enhancement of vulnerability, senescence and finally death. Mechanisms which underlie ageing are primarily attributed to an array of diverse but related factors including free radical-induced damage, dysfunction of mitochondria, disruption of circadian rhythms, inflammaging, genomic instability, telomere attrition, loss of proteostasis, deregulated sensing of nutrients, epigenetic alterations, altered intercellular communication, and decreased capacity for tissue repair. Melatonin, a prime regulator of human chronobiological and endocrine physiology, is highly reputed as an antioxidant, immunomodulatory, antiproliferative, oncostatic, and endocrine-modulatory molecule. Interestingly, several recent reports support melatonin as an anti-ageing agent whose multifaceted functions may lessen the consequences of ageing. This review depicts four categories of melatonin's protective effects on ageing-induced molecular and structural alterations. We also summarize recent findings related to the function of melatonin during ageing in various tissues and organs.

Comparative Analysis of B-Cell Receptor Repertoires Induced by Live Yellow Fever Vaccine in Young and Middle-Age Donors

Age-related changes can significantly alter the state of adaptive immune system and often lead to attenuated response to novel pathogens and vaccination. In present study we employed 5′RACE UMI-based full length and nearly error-free immunoglobulin profiling to compare plasma cell antibody repertoires in young (19–26 years) and middle-age (45–58 years) individuals vaccinated with a live yellow fever vaccine, modeling a newly encountered pathogen. Our analysis has revealed age-related differences in the responding antibody repertoire ranging from distinct IGH CDR3 repertoire properties to differences in somatic hypermutation intensity and efficiency and antibody lineage tree structure. Overall, our findings suggest that younger individuals respond with a more diverse antibody repertoire and employ a more efficient somatic hypermutation process than elder individuals in response to a newly encountered pathogen.

The effect of zinc and melatonin supplementation on immunity parameters in breast cancer induced by DMBA in rats

OBJECTIVE

The aim of the study was to determine the effects of zinc and melatonin supplements on the immunity parameters of female rats with breast cancer induced by DMBA.

METHODS

Group 1; Control, Group 2; 7,12-dimethylbenz[a]anthracene (DMBA), Group 3; DMBA + zinc, Group 4; DMBA + melatonin, Group 5; DMBA + zinc + melatonin. The rats' breast cancer was induced by DMBA 80 mg/kg. Groups 3-5 received daily 5 mg/kg doses of zinc, melatonin, and zinc + melatonin, respectively. Lymphocyte rates, T-lymphocyte subgroups, B-lymphocyte and natural killer cells (NK), and natural killer T (NKT) were evaluated.

RESULTS

The most significant increase in lymphocyte, T-lymphocyte, and CD4 lymphocyte rates was found in Group 5. The highest NKT cell rates were found in Group 3.

CONCLUSIONS

Findings show that zinc and melatonin supplements have led to an increase in the immunity parameters of rats with breast cancer.

Immunosenescence: the Role of Aging in the Predisposition to Neuro-Infectious Complications Arising from the Treatment of Multiple Sclerosis

PURPOSE OF REVIEW

This review highlights some of the important changes in the immune system that occur in the process of normal aging. Immunosenescence as a concept is directly relevant to the world of neuro-inflammation, as it may be a contributing factor to the risks associated with some of the current immunosuppressive and immunomodulatory therapies used in treating multiple sclerosis (MS) and other inflammatory disorders.

RECENT FINDINGS

Profound qualitative and quantitative changes occur in the adaptive and innate immunity compartments during aging. These changes may explain why patients of older age are at an increased risk of infections and infection-associated mortality. Immunosenescence-associated changes may be additive or synergistic with the effects produced by immunomodulatory and immunosuppressive medications. Clinicians should exercise a high level of vigilance in monitoring the risk of infections in older patients on these treatments.

Immune function parameters as markers of biological age and predictors of longevity

Chronological age is not a good indicator of how each individual ages and thus how to maintain good health. Due to the long lifespan in humans and the consequent difficulty of carrying out longitudinal studies, finding valid biomarkers of the biological age has been a challenge both for research and clinical studies. The aim was to identify and validate several immune cell function parameters as markers of biological age. Adult, mature, elderly and long-lived human volunteers were used. The chemotaxis, phagocytosis, natural killer activity and lymphoproliferation in neutrophils and lymphocytes of peripheral blood were analyzed. The same functions were measured in peritoneal immune cells from mice, at the corresponding ages (adult, mature, old and long lived) in a longitudinal study. The results showed that the evolution of these functions was similar in humans and mice, with a decrease in old subjects. However, the long-lived individuals maintained values similar to those in adults. In addition, the values of these functions in adult prematurely aging mice were similar to those in chronologically old animals, and they died before their non-prematurely aging mice counterparts. Thus, the parameters studied are good markers of the rate of aging, allowing the determination of biological age.

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.

Differential Effect of Cytomegalovirus Infection with Age on the Expression of CD57, CD300a, and CD161 on T-Cell Subpopulations

Immunosenescence is a progressive deterioration of the immune system with aging. It affects both innate and adaptive immunity limiting the response to pathogens and to vaccines. As chronic cytomegalovirus (CMV) infection is probably one of the major driving forces of immunosenescence, and its persistent infection results in functional and phenotypic changes to the T-cell repertoire, the aim of this study was to analyze the effect of CMV-seropositivity and aging on the expression of CD300a and CD161 inhibitory receptors, along with the expression of CD57 marker on CD4⁺, CD8⁺, CD8⁺CD56⁺ (NKT-Like) and CD4⁻CD8⁻ (DN) T-cell subsets. Our results showed that, regardless of the T-cell subset, CD57⁻CD161⁻CD300a⁺ T-cells expand with age in CMV-seropositive individuals, whereas CD57⁻CD161⁺CD300a⁺ T-cells decrease. Similarly, CD57⁺CD161⁻CD300a⁺ T-cells expand with age in CMV-seropositive individuals in all subsets except in DN cells and CD57⁻CD161⁺CD300a⁻ T-cells decrease in all T-cell subsets except in CD4⁺ T-cells. Besides, in young individuals, CMV latent infection associates with the expansion of CD57⁺CD161⁻CD300a⁺CD4⁺, CD57⁻CD161⁻CD300a⁺CD4⁺, CD57⁺CD161⁻CD300a⁺CD8⁺, CD57⁻CD161⁻CD300a⁺CD8⁺, CD57⁺CD161⁻CD300a⁺NKT-like, and CD57⁺CD161⁻CD300a⁺DN T-cells. Moreover, in young individuals, CD161 expression on T-cells is not affected by CMV infection. Changes of CD161 expression were only associated with age in the context of CMV latent infection. Besides, CD300a⁺CD57⁺CD161⁺ and CD300a⁻CD57⁺CD161⁺ phenotypes were not found in any of the T-cell subsets studied except in the DN subpopulation, indicating that in the majority of T-cells, CD161 and CD57 do not co-express. Thus, our results show that CMV latent infection impact on the immune system depends on the age of the individual, highlighting the importance of including CMV serology in any study regarding immunosenescence.

Interleukin-7 and Immunosenescence

The age of an individual is an important, independent risk factor for many of the most common diseases afflicting modern societies. Interleukin-7 (IL-7) plays a central, critical role in the homeostasis of the immune system. Recent studies support a critical role for IL-7 in the maintenance of a vigorous healthspan. We describe the role of IL-7 and its receptor in immunosenescence, the aging of the immune system. An understanding of the role that IL-7 plays in aging may permit parsimonious preventative or therapeutic solutions for diverse conditions. Perhaps IL-7 might be used to "tune" the immune system to optimize human healthspan and longevity.

Reduced Intestinal Motility, Mucosal Barrier Function, and Inflammation in Aged Monkeys

OBJECTIVE

We aimed to examine the general health and intestinal physiology of young and old non-human primates with comparable life histories and dietary environments.

DESIGN

Vervet monkeys (Chlorcebus aethiops sabaeus) in stable and comparable social and nutritional environments were selected for evaluation. Health phenotype, circulating cytokines and biomarkers of microbial translocation (MT) were measured (n=26-44). Subsets of monkeys additionally had their intestinal motility, intestinal permeability, and fecal microbiomes characterized. These outcomes document age-related intestinal changes present in the absence of nutritional stressors, which are all known to affect gastrointestinal motility, microbiome, and MT.

RESULTS

We found that old monkeys have greater systemic inflammation and poor intestinal barrier function as compared to young monkeys. Old monkeys have dramatically reduced intestinal motility, and all changes in motility and MT are present without large differences in fecal microbiomes.

CONCLUSION

We conclude that deteriorating intestinal function is a feature of normal aging and could represent the source of inflammatory burden yet to be explained by disease or diet in normal aging human primate populations. Intestinal changes were seen independent of dietary influences and aging within a consistent environment appears to avoid major microbiome shifts. Our data suggests interventions to promote intestinal motility and mucosal barrier function have the potential to support better health with aging.

Immune Responses to Influenza Virus and Its Correlation to Age and Inherited Factors

Influenza viruses belong to the family Orthomyxoviridae of enveloped viruses and are an important cause of respiratory infections worldwide. The influenza virus is able to infect a wide variety species as diverse as poultry, marine, pigs, horses, and humans. Upon infection with influenza virus the innate immunity plays a critical role in efficient and rapid control of viral infections as well as in adaptive immunity initiation. The humoral immune system produces antibodies against different influenza antigens, of which the HA-specific antibody is the most important for neutralization of the virus and thus prevention of illness. Cell mediated immunity including CD4+ helper T cells and CD8+ cytotoxic T cells are the other arms of adaptive immunity induced upon influenza virus infection. The complex inherited factors and age related changes are associated with the host immune responses. Here, we review the different components of immune responses against influenza virus. Additionally, the correlation of the immune response to age and inherited factors has been discussed. These determinations lead to a better understanding of the limitations of immune responses for developing improved vaccines to control influenza virus infection.

Oral exposure to Listeria monocytogenes in aged IL-17RKO mice: A possible murine model to study listeriosis in susceptible populations

Foodborne Listeria monocytogenes (LM) is a cause of serious illness and death in the US. The case-fatality rate of invasive LM infection in the elderly population is >50%. The goal of this study is to establish a murine model of oral LM infection that can be used as a surrogate for human foodborne listeriosis in the geriatric population. Adult C57BL/6 (wild-type, WT) and adult or old IL17R-KO (knock-out) mice were gavaged with a murinized LM strain (Lmo-InlA^m) and monitored for body-weight loss and survivability. Tissues were collected and assayed for bacterial burden, histology, and cytokine responses. When compared to WT mice, adult IL17R-KO mice are more susceptible to LM infection and showed increased LM burden and tissue pathology and a higher mortality rate. Older LM-infected KO-mice lost significantly (p < 0.02, ANOVA) more body-weight and had a higher bacterial burden in the liver (p = 0.03) and spleen as compared to adult mice. Uninfected, aged KO-mice showed a higher baseline pro-inflammatory response when compared to uninfected adult-KO mice. After infection, the pro-inflammatory cytokine, IFN-γ, mRNA in the liver was higher in the adult mice as compared to the old mice. The anti-inflammatory cytokine, IL-10, mRNA and regulatory T-cells (CD4⁺CD25^+h or CD4⁺Foxp3⁺) cells in the aged mice increased significantly after infection as compared to adult mice. Expression of the T-cell activation marker, CD25 (IL-2Rα) in the aged mice did not increase significantly over baseline. These data suggest that aged IL17R-KO mice can be used as an in vivo model to study oral listeriosis and that aged mice are more susceptible to LM infection due to dysregulation of pro- and anti-inflammatory responses compared to adult mice, resulting in a protracted clearance of the infection.

Genetic Influence on the Peripheral Blood CD4+ T-cell Differentiation Status in CMV Infection

A latent infection with cytomegalovirus (CMV), a ubiquitous beta herpesvirus, is associated with an accumulation of late-differentiated memory T-cells, often accompanied by a reciprocal reduced frequency of early-differentiated cells (commonly also referred to as "naïve"). However, this impact of CMV on T-cell phenotypes is variable between individuals. Our previous findings in a subgroup of participants in the Leiden familial Longevity Study indicated an important role of genetics. For further testing, we have analyzed middle-aged monozygotic (MZ, n = 42) and dizygotic (DZ, n = 39) twin pairs from the Danish Twin Registry for their T-cell differentiation status, assessed by surface expression of CD27, CD28, CD57, and KLRG-1. We observed a significant intraclass correlation between cotwins of MZ, but not DZ pairs for the differentiation status of CD4⁺ and CD8⁺ subsets. Classical heritability analysis confirmed a substantial contribution of genetics to the differentiation status of T-cells in CMV infection. The humoral (IgG) response to different CMV antigens also seems to be genetically influenced, suggesting that a similar degree of immune control of the virus in MZ twins might be responsible for their similar T-cell differentiation status. Thus, the way T-cells differentiate in the face of a latent CMV infection, and the parallel humoral responses, both controlling the virus, are genetically influenced.

A systematic review and meta-analysis regarding the use of corticosteroids in septic arthritis

Background

Chondral damage is one of the major sequelae of septic arthritis; occurring even after prompt treatment of a septic joint. Subsequent loss of joint function can have a significant impact on a patient’s quality of life. Corticosteroids are known to have beneficial effects on the rate and extent cartilage destruction in arthritis through a variety of mediators such as synovial RANKL expression, mast cells and pro-inflammatory cytokines. Investigation into sepsis at other sites has suggested improved outcomes with corticosteroid use despite the theoretical risks. This study therefore set out to review current literature with regards to a possible beneficial effect for corticosteroids in Septic Arthritis.

Methods

A computerised search of the databases MEDLINE and CINAHL was conducted during November 2014 using the EBSCOhost web search engine in order to identify research articles relating to the use of corticosteroids in the treatment of septic arthritis. The search strategy revealed 223 unique articles which were subjected to inclusion/exclusion criteria assessment. 6 articles were selected for study inclusion. These consisted of 3 human studies (2 double-blind randomised controlled trials & 1 double-blind non-randomised controlled trial), and 3 animal studies (3 non-blinded non-randomised controlled trials). Quantitative synthesis (meta-analysis) was only possible regarding two primary outcomes for two of the included studies – time to normalisation of CRP and duration of IV antibiotic therapy.

Results

All current published evidence in humans is focused upon children. Overall results did however reveal a consensus between these studies for a reduced duration of symptoms and a reduction in inflammatory markers. Animal data suggested a protective effect on the articular cartilage with the addition of corticosteroids to antibiotic therapy. No article noted an adverse effect associated with steroid use. Findings were consistent with systematic reviews of corticosteroid use in other bacterial infections.

Conclusions

Despite the promising outlook, issues’ regarding generalisability of results and a lack of large randomised controlled trial data necessitates further assessment of the safety and efficacy of steroid use in adults before treatment recommendations can be made. Long term safety data and the determinations of the optimum route, dose and timing of corticosteroids are also required.

Effects of yogurt containing Lactobacillus plantarum HOKKAIDO on immune function and stress markers

Lactobacillus plantarum HOKKAIDO (HOKKAIDO strain) was isolated from well-pickled vegetables in Hokkaido, Japan. We report a randomized, double-blind, placebo-controlled study evaluating the effects of L. plantarum HOKKAIDO on immune function and stress markers in 171 adult subjects. Subjects were divided into three groups: the L. plantarum HOKKAIDO yogurt group, the placebo-1 group who ingested yogurt without the HOKKAIDO strain, and the placebo-2 group who ingested a yogurt-like dessert without the HOKKAIDO strain. Hematological tests and body composition measurements were performed before and after 4 and 8 weeks of blinded ingestion. Although no significant differences in natural killer cell activity were observed, it was found that neutrophil ratio significantly decreased and lymphocytes tended to increase in the HOKKAIDO strain yogurt group compared with the yogurt-like dessert group. In addition, the neutrophil-to-lymphocyte ratio, a stress marker, tended to improve in the HOKKAIDO strain yogurt group compared with the yogurt-like dessert group. These results suggest that the ingestion of HOKKAIDO strain yogurt tends to improve immune activity and decrease stress markers.

In vitro caloric restriction induces protective genes and functional rejuvenation in senescent SAMP8 astrocytes

Astrocytes are key cells in brain aging, helping neurons to undertake healthy aging or otherwise letting them enter into a spiral of neurodegeneration. We aimed to characterize astrocytes cultured from senescence-accelerated prone 8 (SAMP8) mice, a mouse model of brain pathological aging, along with the effects of caloric restriction, the most effective rejuvenating treatment known so far. Analysis of the transcriptomic profiles of SAMP8 astrocytes cultured in control conditions and treated with caloric restriction serum was performed using mRNA microarrays. A decrease in mitochondrial and ribosome mRNA, which was restored by caloric restriction, confirmed the age-related profile of SAMP8 astrocytes and the benefits of caloric restriction. An amelioration of antioxidant and neurodegeneration-related pathways confirmed the brain benefits of caloric restriction. Studies of oxidative stress and mitochondrial function demonstrated a reduction of oxidative damage and partial improvement of mitochondria after caloric restriction. In summary, caloric restriction showed a significant tendency to normalize pathologically aged astrocytes through the activation of pathways that are protective against the age-related deterioration of brain physiology.

The inverted CD4:CD8 ratio is associated with gender-related changes in oxidative stress during aging

Aging has been associated with increased generation of free radicals as well as immunosenescence. Previous studies have identified older individuals with inverted T CD4:CD8 cell ratio and increased immunity to cytomegalovirus (CMV). Here, we investigated markers of oxidative stress and antioxidant defences in older individuals with inverted CD4:CD8 T-cell ratio. Sixty-one subjects were identified with inverted CD4:CD8 ratio. Older individuals with a CD4:CD8 ratio <1 had increased levels of plasma advanced oxidation protein products (AOPP) and ferric reducing ability of plasma (FRAP), but reduced levels of thiobarbituric acid reactive substances (TBARS) as compared to subjects with normal CD4:CD8 ratio. The CMV IgG serology was negatively correlated with CD4:CD8 ratio. These markers were more evident among elderly men than women. Our data suggest a close relationship between chronic CMV infection and oxidative profile in older individuals in the midst of its influence on the peripheral T-cell subsets.

Expression of NKp30, NKp46 and DNAM-1 activating receptors on resting and IL-2 activated NK cells from healthy donors according to CMV-serostatus and age

Human natural killer (NK) cells are innate lymphoid cells with capacity to kill tumor cells and virus-infected cells. According to the expression of CD56 and CD16 several NK cell subsets have been identified, a major CD56dimCD16+ subpopulation characterized by higher cytotoxic capacity, two CD56bright subsets (CD16-and CD16+) that represent different maturation stages and the fourth CD56-CD16+ subset that correspond to activated dysfunctional NK cells. Previous studies have shown quantitative changes in the frequency, phenotype and distribution of NK cell subsets depending on CMV-serostatus and age. We have analyzed the expression of NKp30, NKp46 and DNAM-1 NK activating receptors on resting and IL-2 activated NK cells from CMV-seronegative and seropositive healthy young donors and from CMV-seropositive elderly individuals. Our results showed that CMV-serostatus of healthy young donors is associated with phenotypic differences on both CD56bright and CD56dim NK cells with an increase of NKp46 and a decrease of NKp30 expression respectively. A reduced expression of DNAM-1 related to ageing and a lower NKp30 expression associated with CMV-seropositivity were observed. The expression of NKp46 and NKp30 was lower in CD57+ NK cells while the expression of DNAM-1 was increased. In vitro NK cell activation by IL-2 increased the expression of NKp46 and NKp30. In summary, both age and CMV-serostatus influence the expression of these cytotoxicity activating receptors that will have functional consequences. In elderly donors is difficult to isolate age from the effect of chronic CMV infection since in our study all elderly donors were CMV-seropositive. The possibility of modulating the expression of these activating receptors by cytokines such as IL-2 may open new opportunities for improving age-associated deterioration of NK cell function.

Immunosenescence: Implications for response to infection and vaccination in older people

People aged 60 and older represent over 11% of the world population and it is expected to rise 22% by 2050. Population aging is associated to an increased frequency of age-related diseases including higher susceptibility to infections, cancer, cardiovascular and neurodegenerative diseases. Immunosenescence refers to the decline of the immune system associated to aging. It affects both, innate and adaptive immunity limiting the response to pathogens and to vaccines. The analyses of the immune system in elderly individuals determined several immune signatures constituting an immune risk phenotype that predicts mortality. An inverse CD4/CD8 ratio, loss of naïve T cells, increased numbers of terminally-differentiated T cells and oligoclonal expansions of virus-specific T cells constitute hallmarks of immunosenescence. Natural killer (NK) cells are also found severely altered in the elderly. The contribution of latent cytomegalovirus infection to immunosenescence of T and NK cells has been shown. Considering the worldwide ageing of the population in the next decades, the impact of infections will be a real health problem for older individuals requiring preventive strategies. Thus, further studies are required to analyse the bases of immunosenescence and to establish protocols to overcome the age-associated alterations of the immune response in order to define effective vaccines against those pathogens, such as influenza, contributing to increased morbidity and mortality in the elderly.

Cytomegalovirus (CMV) seropositivity decreases B cell responses to the influenza vaccine

Cytomegalovirus (CMV)-seropositivity has been shown to have a negative effect on influenza vaccine-specific antibody responses. In this paper, we confirm and extend these results showing for the first time, a negative association between CMV-seropositivity and B cell predictive biomarkers of optimal vaccine responses. These biomarkers are switched memory B cells and AID in CpG-stimulated B cell cultures measured before vaccination which positively correlate with the serum response to the influenza vaccine. We also found that CMV-seropositivity is associated with increased levels of B cell-intrinsic inflammation and these both correlate with lower B cell function. Finally, CMV-seropositivity is associated with decreased percentages of individuals responding to the vaccine in both young and elderly individuals.

CMV latent infection improves CD8+ T response to SEB due to expansion of polyfunctional CD57+ cells in young individuals

Cytomegalovirus (CMV) latent infection has a deleterious effect on the efficacy of influenza vaccination in the elderly, suggesting that CMV restricts immunological diversity impairing the immune system functionality in old age. Polyfunctional T cells produce multiple cytokines and higher amounts than mono-functional T cells. High number of polyfunctional T cells correlates with better prognosis during infection. Thus, the efficiency of T cell response associates with quality (polyfunctionality) rather than with quantity (percentage of T cells). We analyze the effect of CMV infection on CD8+ T cells polyfunctionality ―degranulation (CD107a), IFN-gamma and TNF-alpha production―, from young CMV-seropositive and CMV-seronegative individuals and in middle age CMV-seropositive donors, in response to Staphylococcal Enterotoxin B (SEB). Our results show a higher percentage of polyfunctional CD8+ T cells in young CMV-seropositive individuals compared to CMV-seronegative. Also, we find an expansion of CD8+CD57+ T cells in CMV-seropositive individuals, which are more polyfunctional than CD8+CD57− cells. In middle age individuals there is a higher frequency of SEB-responding CD8+ T cells, mainly TNF-alpha or TNF-alpha/IFN-gamma producers, whereas the percentage of polyfunctional cells (IFN-gamma/TNF-alpha/CD107a) is similar to the percentages found in young CMV-seropositive. Therefore, whereas it has been shown that CMV latent infection can be detrimental for immune response in old individuals, our results indicate that CMV-seropositivity is associated to higher levels of polyfunctional CD8+ T cells in young and middle age donors. This increase in polyfunctionality, which can provide an immunological advantage in the response to other pathogens, is due to a CD8+CD57+ T cell expansion in CMV-seropositive individuals and it is independent of age. Conversely, age could contribute to the inflammation found in old individuals by increasing the percentage of cells producing pro-inflammatory cytokines. These findings highlight the necessity of further studies on the benefits/detrimental effects of CMV infection in the response to vaccination and other infections.

Nutrition, diet and immunosenescence

Ageing is characterized by immunosenescence and the progressive decline in immunity in association with an increased frequency of infections and chronic disease. This complex process affects both the innate and adaptive immune systems with a progressive decline in most immune cell populations and defects in activation resulting in loss of function. Although host genetics and environmental factors, such as stress, exercise and diet can impact on the onset or course of immunosenescence, the mechanisms involved are largely unknown. This review focusses on identifying the most significant aspects of immunosenescence and on the evidence that nutritional intervention might delay this process, and consequently improve the quality of life of the elderly.

[Premature immunosenescence in triple-transgenic mice for Alzheimer's disease]

INTRODUCTION

A deterioration of the neuroimmunoendocrine network has been observed in Alzheimer's disease (AD). However, the peripheral immune response has hardly been investigated in this pathology. Since some immune function parameters have been established as good markers of the rate of ageing, and can predict longevity, the aim of the present work was to study some of these functions in splenic leucocytes in transgenic mice for AD of different ages.

MATERIAL AND METHODS

Young female (4 ± 1 months), adult (9 ± 1 months), and mature (12 ± 1 months) triple-transgenic mice for AD (3 xTgAD) and non-transgenic (NTg) control mice of the same ages were used. The chemotaxis, the anti-tumour activity of « natural killer » (NK) cells and the lymphoproliferative response in the presence of the mitogens concanavalin A and lipopolysaccharide, functions that decrease with age, were determined in splenic leucocytes. In addition, the differences in lifespan between 3 xTgAD and NTg were studied in parallel using other animals, until their death through natural causes.

RESULTS

In 3 xTgAD, with respect to NTg, chemotaxis decreased at all ages studied, whereas in lymphoproliferative response this reduction was shown at 4 months and 9 months. NK activity was diminished only in young 3 xTgAD with respect to NTg. The 3 xTgAD showed a shorter lifespan than the NTg control group.

CONCLUSIONS

The 3 xTgAD mice show a premature immunosenescence, which could explain their early mortality. The determination of these immune functions at peripheral level could serve as a marker of the progression of the Alzheimer's disease.

Melatonin and the theories of aging: a critical appraisal of melatonin's role in antiaging mechanisms

The classic theories of aging such as the free radical theory, including its mitochondria-related versions, have largely focused on a few specific processes of senescence. Meanwhile, numerous interconnections have become apparent between age-dependent changes previously thought to proceed more or less independently. Increased damage by free radicals is not only linked to impairments of mitochondrial function, but also to inflammaging as it occurs during immune remodeling and by release of proinflammatory cytokines from mitotically arrested, DNA-damaged cells that exhibit the senescence-associated secretory phenotype (SASP). Among other effects, SASP can cause mutations in stem cells that reduce the capacity for tissue regeneration or, in worst case, lead to cancer stem cells. Oxidative stress has also been shown to promote telomere attrition. Moreover, damage by free radicals is connected to impaired circadian rhythmicity. Another nexus exists between cellular oscillators and metabolic sensing, in particular to the aging-suppressor SIRT1, which acts as an accessory clock protein. Melatonin, being a highly pleiotropic regulator molecule, interacts directly or indirectly with all the processes mentioned. These influences are critically reviewed, with emphasis on data from aged organisms and senescence-accelerated animals. The sometimes-controversial findings obtained either in a nongerontological context or in comparisons of tumor with nontumor cells are discussed in light of evidence obtained in senescent organisms. Although, in mammals, lifetime extension by melatonin has been rarely documented in a fully conclusive way, a support of healthy aging has been observed in rodents and is highly likely in humans.

Does aging affect the immune status? A comparative analysis in 300 healthy volunteers from France, Austria and Spain

Background

As the European population is getting older, there is growing need in scientific data on how to achieve healthy and successful aging. A decline in immune function with age is unanimously supported by many epidemiological and clinical observations, with a decrease in T-cell mediated function encompassing a large part of this alteration. In the EU-funded VITAGE project, the effects of aging on biomarkers of immune status are being studied in three European countries. According to strict inclusion/exclusion criteria, a cohort of 300 healthy male non-smoking 20–75 years old volunteers were enrolled in France (n = 99), Spain (n = 100) and Austria (n = 101). In each country, the volunteers were classified as a function of age (one age group per decade). Biomarkers of immune status were determined including delayed-type hypersensitivity tests, measurement of lymphocyte surface markers, and serum determinations of interleukin-2, complement fractions and immunoglobulins.

Results

There were moderate differences in the biomarkers of immune status of the VITAGE study volunteers among the three European centres. The percentage of Natural Killer (NK) cells was 156% and 142% higher in Spain as compared to France and Austria, respectively (p < 0.0001), and this increase was observed at any age group above 30 years. Comparison between age-groups showed that in Spain, but not in France or Austria, older individuals had significantly a lower B lymphocyte distribution and conversely, a higher NK cell distribution. Moreover, the CD4/CD8 ratio was positively correlated with age in Austrian subjects (p < 0.0001).

Conclusion

Our results provide evidence of an increased NK cell distribution in the elderly, especially in the Spanish population. NK cell status may predict morbidity and mortality in the elderly, emphasizing the importance of innate as well as adaptive immunity in ensuring healthy longevity and cancer resistance, possibly in link with the Mediterranean diet.

Oral supplementation with Lactobacillus delbrueckii subsp. bulgaricus 8481 enhances systemic immunity in elderly subjects

Throughout life, there is an aging of the immune system that causes impairment of its defense capability. Prevention or delay of this deterioration is considered crucial to maintain general health and increase longevity. We evaluated whether dietary supplementation with Lactobacillus delbrueckii subsp. bulgaricus 8481 could enhance the immune response in the elderly. This multi-center, double-blind, and placebo controlled study enrolled 61 elderly volunteers who were randomly assigned to receive either placebo or probiotics. Each capsule of probiotics contained at least 3 × 10(7)  L. delbrueckii subsp. bulgaricus 8481. Individuals in the study were administered three capsules per day for 6 months. Blood samples were obtained at baseline (time 0), end of month 3, and month 6. We characterized cell subpopulations, measured cytokines by flow cytometry, quantified T cell receptor excision circle (TREC) by real-time PCR (RT-PCR), and determined human β-defensin-2 (hBD-2) concentrations and human cytomegalovirus (CMV) titers by enzyme-linked immunosorbent assay (ELISA). Elderly responded to the intake of probiotic with an increase in the percentage of NK cells, an improvement in the parameters defining the immune risk profile (IRP), and an increase in the T cell subsets that are less differentiated. The probiotic group also showed decreased concentrations of the pro-inflammatory cytokine IL-8 but increased antimicrobial peptide hBD-2. These effects disappeared within 6 months of stopping the probiotic intake. Immunomodulation induced by L. delbrueckii subsp. bulgaricus 8481 could favor the maintenance of an adequate immune response, mainly by slowing the aging of the T cell subpopulations and increasing the number of immature T cells which are potential responders to new antigens.