Neutrophils of Centenarians Show Function Levels Similar to Those of Young Adults

Systemic inflammation in relation to exceptional memory in the Long Life Family Study (LLFS)

Background and objectives

We previously found a substantial familial aggregation of healthy aging phenotypes, including exceptional memory (EM) in long-lived persons. In the current study, we aim to assess whether long-lived families with EM and without EM (non-EM) differ in systemic inflammation status and trajectory.

Methods

The current study included 4333 participants of the multi-center Long Life Family Study (LLFS). LLFS families were classified as EM (556 individuals from 28 families) or non-EM (3777 individuals from 416 families), with 2 or more offspring exhibiting exceptional memory performance (i.e. having baseline composite z-score representing immediate and delayed story memory being 1.5 SD above the mean in the nondemented offspring sample) considered as EM. Blood samples from baseline were used to measure inflammatory biomarkers including total white blood cell (WBC) and its subtypes (neutrophils, lymphocytes, monocytes) count, platelet count, high sensitivity C-reactive protein, and interleukin-6. Generalized linear models were used to examine cross-sectional differences in inflammatory biomarkers at baseline. In a sub-sample of 2227 participants (338 subjects from 24 EM families and 1889 from 328 non-EM families) with repeated measures of immune cell counts, we examined whether the rate of biomarker change differed between EM and non-EM families. All models were adjusted for family size, relatedness, age, sex, education, field center, APOE genotype, and body mass index.

Results

LLFS participants from EM families had a marginally higher monocyte count at baseline (b = 0.028, SE = 0.0110, p = 0.010) after adjusting for age, sex, education, and field site, particularly in men (p < 0.0001) but not in women (p = 0.493) (p-interaction = 0.003). Over time, monocyte counts increased (p < 0.0001) in both EM and non-EM families, while lymphocytes and platelet counts decreased over time in the non-EM families (p < 0.0001) but not in the EM families. After adjusting for multiple variables, there was no significant difference in biomarker change over time between the EM and non-EM families.

Discussion

Compared with non-EM families, EM families had significantly higher monocyte count at baseline but had similar change over time. Our study suggests that differences in monocyte counts may be a pathway through which EM emerges in some long-lived families, especially among men.

Targeting neutrophils: Mechanism and advances in cancer therapy

BACKGROUND

Cancer is a thorny problem which cannot be conquered by mankind at present and recent researchers have put their focus on tumor microenviroment. Neutrophils, the prominent leukocytes in peripheral blood that accumulate in tumours, serves as frontline cells in response to tumour progression owing to the rapid development of micro biotechnology. Hence, targeted therapy with these neutrophils has made targeting treatment a promising field in cancer therapy.

MAIN BODY

We broadly summarise some studies on the phenotypes and functions of tumour-associated neutrophils as well as the unique web-like products of neutrophils that play a role in cancer progression-neutrophil extracellular traps-and the interactions between neutrophils and the tumour microenvironment. Moreover, several targeted neutrophils therapeutic studies have made some progress and provided potential strategies for the treatment of cancer.

CONCLUSION

This review aims to offer a holistic perspective on therapeutic interventions targeting neutrophils to further inspire more researches on cancer therapies.

Glycyrrhizic acid inhibits myeloid differentiation of hematopoietic stem cells by binding S100 calcium binding protein A8 to improve cognition in aged mice

BACKGROUND

Glycyrrhizic acid (GA), a saponin compound often used as a flavoring agent, can elicit anti-inflammatory and anti-tumor effects, and alleviate aging. However, the specific mechanism by which GA alters immune cell populations to produce these beneficial effects is currently unclear.

RESULTS

In this study, we systematically analyzed single-cell sequencing data of peripheral blood mononuclear cells from young mice, aged mice, and GA-treated aged mice. Our in vivo results show that GA reduced senescence-induced increases in macrophages and neutrophils, and increased numbers of lymphoid lineage subpopulations specifically reduced by senescence. In vitro, GA significantly promoted differentiation of Lin^-CD117⁺ hematopoietic stem cells toward lymphoid lineages, especially CD8⁺ T cells. Moreover, GA inhibited differentiation of CD4⁺ T cells and myeloid (CD11b⁺) cells by binding to S100 calcium-binding protein 8 (S100A8) protein. Overexpression of S100A8 in Lin^- CD117⁺ hematopoietic stem cells enhanced cognition in aged mice and the immune reconstitution of severely immunodeficient B-NDG (NOD.CB17-Prkdcscid/l2rgtm1/Bcgen) mice.

CONCLUSIONS

Collectively, GA exerts anti-aging effects by binding to S100A8 to remodel the immune system of aged mice.

Sex differences in neuroimmunoendocrine communication. Involvement on longevity

Endocrine, nervous, and immune systems work coordinately to maintain the global homeostasis of the organism. They show sex differences in their functions that, in turn, contribute to sex differences beyond reproductive function. Females display a better control of the energetic metabolism and improved neuroprotection and have more antioxidant defenses and a better inflammatory status than males, which is associated with a more robust immune response than that of males. These differences are present from the early stages of life, being more relevant in adulthood and influencing the aging trajectory in each sex and may contribute to the different life lifespan between sexes.

Loneliness, Depression, and Genetics in the Elderly: Prognostic Factors of a Worse Health Condition?

Loneliness is considered a prognostic factor for poorer health status in the elderly. It is proposed to analyze the role of loneliness in health status in terms of various factors. A total of 1747 individuals from the pilot survey of the Aging in Spain Longitudinal Study (ELES-PS) were reviewed. ELES is a cross-sectional study for collecting health variables, food habits, socioeconomic data, and cognitive and functional capacities, which was carried out on a Spanish representative sample of noninstitutionalized persons of 50 years of age or older. Moreover, since telomere shortening is associated with cellular senescence, 35 telomere-related SNPs and cognitive impairments were analyzed. The results characterize the "solos" as males of 50-60 years, who were overweight and had lower levels of hemoglobin and neutrophils. There is also an association between five SNPs related to telomere length and BDNF. A group of people with loneliness and depression was identified with poorer health and cognitive status, poorer perception of their quality of life, poorer quality of sleep, and lower physical activity. Therefore, it follows that telomeres and BDNF play a role as intermediaries between loneliness and depression and their relationship with a worse state of health.

Age-related macular degeneration and myeloproliferative neoplasms - A common pathway

DANSK RESUMÉ (DANISH SUMMARY): Aldersrelateret makuladegeneration (AMD) er den hyppigste årsag til uopretteligt synstab og blindhed i højindkomstlande. Det er en progredierende nethindesygdom som gradvist fører til ødelaeggelse af de celler som er ansvarlige for vores centralsyn. De tidlige stadier er ofte asymptomatiske, imens senstadie AMD, som opdeles i to former, neovaskulaer AMD (nAMD) og geografisk atrofi (GA), begge udviser gradvist synstab, dog generelt med forskellig hastighed. Tidlig AMD er karakteriseret ved tilstedevaerelsen af druser og pigmentforandringer i nethinden mens nAMD og GA udviser henholdsvis karnydannelse i og atrofi af nethinden. AEtiologien er multifaktoriel og udover alder omfatter patogenesen miljø- og genetiske risikofaktorer. Forskning har specielt fokuseret på lokale forandringer i øjet hvor man har fundet at inflammation spiller en betydelig rolle for udviklingen af sygdommen, men flere studier tyder også på at systemiske forandringer og specielt systemisk inflammation spiller en vaesentlig rolle i patogenesen. De Philadelphia-negative myeloproliferative neoplasier (MPNs) er en gruppe af haematologiske kraeftsygdomme med en erhvervet genetisk defekt i den tidlige pluripotente stamcelle som medfører en overproduktion af en eller flere af blodets modne celler. Sygdommene er fundet at udvikle sig i et biologisk kontinuum fra tidligt cancerstadie, essentiel trombocytose (ET) over polycytaemi vera (PV) og endelig til det sene myelofibrose stadie (PMF). Symptomer hos disse patienter skyldes isaer den aendrede sammensaetning af blodet, hyperviskositet, kompromitteret mikrocirkulation og nedsat vaevsgennemblødning. Den øgede morbiditet og mortalitet beror i høj grad på tromboembolier, blødninger og leukemisk transformation. En raekke mutationer som driver MPN sygdommene er identificeret, bl.a. JAK2V617F-mutationen som medfører en deregulering JAK/STAT signalvejen, der bl.a. har betydning for cellers vaekst og overlevelse. Et tidligere stort registerstudie har vist at patienter med MPNs har en øget risiko for neovaskulaer AMD og et pilotstudie har vist øget forekomst af intermediaer AMD. Dette ønsker vi at undersøge naermere i et større studie i dette Ph.d.- projekt. Flere studier har også vist at kronisk inflammation spiller en vigtig rolle for både initiering og udvikling af den maligne celleklon hos MPNs og herfra er en "Human Inflammationsmodel" blevet udviklet. Siden er MPN sygdommene blevet anvendt som "model sygdomme" for en tilsvarende inflammationsmodel for udvikling af Alzheimers sygdom. I dette Ph.d.-projekt vil vi tilsvarende forsøge at undersøge systemisk inflammation i forhold til forekomst af druser. Det vil vi gøre ved at sammenligne systemiske immunologiske markører som tidligere er undersøgt hos patienter med AMD og sammenligne med MPN. Specielt er vi interesseret i systemiske immunologiske forskelle på patienter med MPN og druser (MPNd) og MPN med normale nethinder (MPNn). Denne afhandling består af to overordnede studier. I Studie I, undersøgte vi forekomsten af retinale forandringer associeret med AMD hos 200 patienter med MPN (artikel I). Studie II, omhandlede immunologiske ligheder ved AMD og MPN, og var opdelt i yderligere tre delstudier hvor vi undersøgte hhv. systemiske markører for inflammation, aldring og angiogenese (artikel II, III og IV). Vi undersøgte markørerne i fire typer af patienter: nAMD, intermediaer AMD (iAMD), MPNd og MPNn. Undersøgelsen af forskelle mellem MPNd og MPNn, vil gøre det muligt at identificere forandringer i immunsystemet som kunne vaere relevante for AMD-patogenesen. Vi vil endvidere sammenholde resultaterne for patienter med MPN med patienter som har iAMD og nAMD. I studie I (Artikel I) fandt vi at patienter med MPN har en signifikant højere praevalens af store druser og AMD tidligere i livet sammenlignet med estimater fra tre store befolkningsundersøgelser. Vi fandt også at forekomst af druser var associeret med højere neutrofil-lymfocyt ratio, hvilket indikerer et højere niveau af kronisk inflammation i patienterne med druser sammenlignet med dem uden druser. I studie II (Artikel II, III og IV) fandt vi flere immunologiske forskelle mellem patienter med MPNd og MPNn. Da vi undersøgte markører for inflammation, fandt vi en højere grad af systemisk inflammation i MPNd end MPNn. Dette blev vist ved en højere inflammationsscore (udregnet på baggrund af niveauer af pro-inflammatoriske markører), en højere neutrofil-lymfocyt ratio, samt indikationer på et dereguleret komplementsystem. Ved undersøgelse af aldringsmarkører fandt vi tegn på accelereret immunaldring hos MPNd i forhold til MPNn, hvilket kommer til udtryk ved en større procentdel af "effector memory T celler". Endelig fandt vi en vaesentlig lavere ekspression af CXCR3 på T celler og monocytter hos patienter med nAMD sammenlignet med iAMD, MPNd og MPNn. Dette er i overensstemmelse med tidligere studier hvor CXCR3 ekspression er fundet lavere end hos raske kontroller. Derudover fandt vi en faldende CXCR3 ekspression på monocytter over det biologiske MPN-kontinuum. Disse studier indikerer en involvering af CXCR3 i både nAMD og PMF, begge sygdomsstadier som er karakteriseret ved angiogenese og fibrose. Ud fra resultaterne af denne afhandling kan vi konkludere at forekomsten af druser og AMD hos MPN er øget i forhold til baggrundsbefolkningen. Endvidere viser vores resultater at systemisk inflammation muligvis spiller en vaesentlig større rolle i udviklingen af AMD end tidligere antaget. Vi foreslår derfor en AMD-model (Figur 18) hvor inflammation kan initiere og accelerere den normale aldersafhaengige akkumulation af affaldsstoffer i nethinden, som senere udvikler sig til druser, medførende øget lokal inflammation og med tiden tidlig og intermediaer AMD. Dette resulterer i den øgede risiko for udvikling til de invaliderende senstadier af AMD. ENGLISH SUMMARY: Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss and blindness in high-income countries. It is a progressive retinal disease leading to damage of the cells responsible for central vision. The early stages of the disease are often asymptomatic, while late-stage AMD, which is divided into two entities, neovascular AMD and geographic atrophy (GA), both show vision loss, though generally with different progression rates. Drusen and pigmentary abnormalities in the retina characterise early AMD, while nAMD and GA show angiogenesis in and atrophy of the retina, respectively. The aetiology is multifactorial and, in addition to ageing, which is the most significant risk factor for developing AMD, environmental- and genetic risk factors are implicated in the pathogenesis. Research has focused on local changes in the eye where inflammation has been found to play an essential role, but studies also point to systemic alterations and especially systemic inflammation to be involved in the pathogenesis. The Philadelphia-negative myeloproliferative neoplasms (MPN) are a group of haematological cancers with an acquired genetic defect of the pluripotent haematopoietic stem cell, characterised by excess haematopoiesis of the myeloid cell lineage. The diseases have been found to evolve in a biological continuum from early cancer state, essential thrombocythemia, over polycythaemia vera (PV), to the advanced myelofibrosis stage (PMF). The symptoms in these patients are often a result of the changes in the blood composition, hyperviscosity, microvascular disturbances, and reduced tissue perfusion. The major causes of morbidity and mortality are thromboembolic- and haemorrhagic events, and leukemic transformation. A group of mutations that drive the MPNs has been identified, e.g., the JAK2V617F mutation, which results in deregulation of the JAK/STAT signal transduction pathway important, for instance, in cell differentiation and survival. A previous large register study has shown that patients with MPNs have an increased risk of neovascular AMD, and a pilot study has shown an increased prevalence of intermediate AMD. We wish to study this further in a larger scale study. Several studies have also shown that systemic inflammation plays an essential role in both the initiation and progression of the malignant cell clone in MPNs. From this knowledge, a "Human inflammation model" has been developed. Since then, the MPNs has been used as model diseases for a similar inflammation model for the development of Alzheimer's disease. In this PhD project, we would like to investigate systemic inflammation in relation to drusen presence. We will do this by comparing systemic immunological markers previously investigated in patients with AMD and compare with MPN. We are primarily interested in systemic immunological differences between patients with MPN and drusen (MPNd) and MPN with normal retinas (MPNn). This thesis consists of two main studies. Study I investigated the prevalence of retinal changes associated with AMD and the prevalence of different AMD stages in 200 patients with MPN (paper I). Study II examined immunological similarities between AMD and MPNs. This study was divided into three substudies exploring systemic markers of inflammation, ageing and angiogenesis, respectively. This was done in four types of patients: nAMD, intermediate AMD (iAMD), MPNd and MPNn. Investigating, differences between MPNd and MPNn, will make it possible to identify changes in the immune system, relevant for AMD pathogenesis. Additionally, we will compare patients with MPNs with patients with iAMD and nAMD. In study I (Paper I), we found that patients with MPNs have a significantly higher prevalence of large drusen and consequently AMD from an earlier age compared to the estimates from three large population-based studies. We also found that drusen prevalence was associated with a higher neutrophil-to-lymphocyte ratio indicating a higher level of chronic low-grade inflammation in patients with drusen compared to those without drusen. In study II (papers II, III and IV), we found immunological differences between patients with MPNd and MPNn. When we investigated markers of inflammation, we found a higher level of systemic inflammation in MPNd than MPNn. This was indicated by a higher inflammation score (based on levels of pro-inflammatory markers), a higher neutrophil-to-lymphocyte ratio, and indications of a deregulated complement system. When examining markers of ageing, we found signs of accelerated immune ageing in MPNd compared to MPNn, shown by more senescent effector memory T cells. Finally, when exploring a marker of angiogenesis, we found a lower CXCR3 expression on monocytes and T cells in nAMD compared to iAMD, MPNd and MPNn, in line with previous studies of nAMD compared to healthy controls. Further, we found decreasing CXCR3 expression over the MPN biological continuum. These studies indicate CXCR3 involvement in both nAMD and PMF, two disease stages characterised by angiogenesis and fibrosis. From the results of this PhD project, we can conclude that the prevalence of drusen and AMD is increased in patients with MPN compared to the general population. Further, our results show that systemic inflammation may play a far more essential role in AMD pathogenesis than previously anticipated. We, therefore, propose an AMD model (Figure 18) where inflammation can initiate and accelerate the normal age-dependent accumulation of debris in the retina, which later evolve into drusen, resulting in increased local inflammation, and over time early- and intermediate AMD. This results in the increased risk of developing the late debilitating stages of AMD.

Age-related decline in the resistance of mice to bacterial infection and in LPS/TLR4 pathway-dependent neutrophil responses

Host defense against bacterial and fungal infections diminishes with age. In humans, impaired neutrophil responses are thought to contribute to this decline. However, it remains unclear whether neutrophil responses are also impaired in old mice. Here, we investigated neutrophil function in old mice, focusing on responses primed by lipopolysaccharide (LPS), an endotoxin released by gram-negative bacteria like E. coli, which signals through toll-like receptor (TLR) 4. We show that old mice have a reduced capacity to clear pathogenic E. coli during septic peritonitis. Neutrophil recruitment was elevated during LPS-induced but not aseptic peritonitis. Neutrophils from old mice showed reduced killing of E. coli. Their reactive oxygen species (ROS) production was impaired upon priming with LPS but not with GM-CSF/TNFα. Phagocytosis and degranulation were reduced in a partially LPS-dependent manner, whereas impairment of NET release in response to S. aureus was independent of LPS. Unexpectedly, chemotaxis was normal, as were Rac1 and Rac2 GTPase activities. LPS-primed activation of Erk and p38 Mapk was defective. PIP₃ production was reduced upon priming with LPS but not with GM-CSF/TNFα, whereas PIP₂ levels were constitutively low. The expression of 5% of neutrophil proteins was dysregulated in old age. Granule proteins, particularly cathepsins and serpins, as well as TLR-pathway proteins and membrane receptors were upregulated, whereas chromatin and RNA regulators were downregulated. The upregulation of CD180 and downregulation of MyD88 likely contribute to the impaired LPS signaling. In summary, all major neutrophil responses except chemotaxis decline with age in mice, particularly upon LPS priming. This LPS/TLR4 pathway dependence resolves previous controversy regarding effects of age on murine neutrophils and confirms that mice are an appropriate model for the decline in human neutrophil function.

Neutrophils and neutrophil extracellular trap components: Emerging biomarkers and therapeutic targets for age-related eye diseases

Age-related eye diseases, including dry eye, glaucoma, age-related macular degeneration, and diabetic retinopathy, represent a major global health issue based on their increasing prevalence and disabling action. Unraveling the molecular mechanisms underlying these diseases will provide novel opportunities to reduce the burden of age-related eye diseases and improve eye health, contributing to sustainable development goals achievement. The impairment of neutrophil extracellular traps formation/degradation processes seems to be one of these mechanisms. These traps formed by a meshwork of DNA and neutrophil cytosolic granule proteins may exacerbate the inflammatory response promoting chronic inflammation, a pivotal cause of age-related diseases. In this review, we describe current findings that suggest the role of neutrophils and their traps in the pathogenesis of the above-mentioned age-related eye diseases. Furthermore, we discuss why these cells and their constituents could be biomarkers and therapeutic targets for dry eye, glaucoma, age-related macular degeneration, and diabetic retinopathy. We also examine the therapeutic potential of some neutrophil function modulators and provide several recommendations for future research in age-related eye diseases.

Rebalancing the unbalanced aged immune system - A special focus on zinc

Nowadays, aging is understood as a dynamic and multifaceted dysregulation process that spares almost no human organ or cell. The immune system being among the most affected, it has been shown predominantly that its integrity determines the tightrope walk between the difference of escaping or suffering from age-related diseases. Next to drug-based anti-aging strategies, micronutrient intervention may represent an emerging but less radical way to slow immune aging. While a sufficient supply of a variety of micronutrients is undeniably important, adequate intake of the trace element zinc appears to tower over others in terms of reaching old age. Inconveniently, zinc deficiency prevalence among the elderly is high, which in turn contributes to increased susceptibility to infection, decreased anti-tumor immunity as well as attenuated response to vaccination. Driven by this research, this review aims to provide a comprehensive and up-to-date overview of the various rebalancing capabilities of zinc in the unbalanced immune system of the elderly. This includes an in-depth and cell type-centered discussion on the role of zinc in immunosenescence and inflammaging. We further address upcoming translational aspects e.g. how zinc deficiency promotes the flourishing of certain pathogenic taxa of the gut microbiome and how zinc supply counteracts such alterations in a manner that may contribute to longevity. In the light of the ongoing COVID-19 pandemic, we also briefly review current knowledge on the interdependency between age, zinc status, and respiratory infections. Based on two concrete examples and considering the latest findings in the field we conclude our remarks by outlining tremendous parallels between suboptimal zinc status and accelerated aging on the one hand and an optimized zinc status and successful aging on the other hand.

The Role of Immune Cells in Oxi-Inflamm-Aging

Aging is the result of the deterioration of the homeostatic systems (nervous, endocrine, and immune systems), which preserve the organism's health. We propose that the age-related impairment of these systems is due to the establishment of a chronic oxidative stress situation that leads to low-grade chronic inflammation throughout the immune system's activity. It is known that the immune system weakens with age, which increases morbidity and mortality. In this context, we describe how the function of immune cells can be used as an indicator of the rate of aging of an individual. In addition to this passive role as a marker, we describe how the immune system can work as a driver of aging by amplifying the oxidative-inflammatory stress associated with aging (oxi-inflamm-aging) and inducing senescence in far tissue cells. Further supporting our theory, we discuss how certain lifestyle conditions (such as social environment, nutrition, or exercise) can have an impact on longevity by affecting the oxidative and inflammatory state of immune cells, regulating immunosenescence and its contribution to oxi-inflamm-aging.

Immunosenescence and inflammaging in the aging process: age-related diseases or longevity?

During aging the immune system (IS) undergoes remarkable changes that collectively are known as immunosenescence. It is a multifactorial and dynamic phenomenon that affects both natural and acquired immunity and plays a critical role in most chronic diseases in older people. For a long time, immunosenescence has been considered detrimental because it may lead to a low-grade, sterile chronic inflammation we proposed to call "inflammaging" and a progressive reduction in the ability to trigger effective antibody and cellular responses against infections and vaccinations. Recently, many scientists revised this negative meaning because it can be considered an essential adaptation/remodeling resulting from the lifelong immunological biography of single individuals from an evolutionary perspective. Inflammaging can be considered an adaptive process because it can trigger an anti-inflammatory response to counteract the age-related pro-inflammatory environment. Centenarians represent a valuable model to study the beneficial changes occurring in the IS with age. These extraordinary individuals reached the extreme limits of human life by slowing down the aging process and, in most cases, delaying, avoiding or surviving the major age-associated diseases. They indeed show a complex and heterogeneous phenotype determined by an improved ability to adapt and remodel in response to harmful stimuli. This review aims to point out the intimate relationship between immunosenescence and inflammaging and how these processes impact unsuccessful aging rather than longevity. We also describe the gut microbiota age-related changes as one of the significant triggers of inflammaging and the sex/gender differences in the immune system of the elderly, contributing to the sex/gender disparity in terms of epidemiology, pathophysiology, symptoms and severity of age-related diseases. Finally, we discuss how these phenomena could influence the susceptibility to COVID-19 infection.

Older but Not Wiser: the Age-Driven Changes in Neutrophil Responses during Pulmonary Infections

Elderly individuals are at increased risk of life-threatening pulmonary infections. Neutrophils are a key determinant of the disease course of pathogen-induced pneumonia. Optimal host defense balances initial robust pulmonary neutrophil responses to control pathogen numbers, ultimately followed by the resolution of inflammation to prevent pulmonary damage. Recent evidence suggests that phenotypic and functional heterogeneity in neutrophils impacts host resistance to pulmonary pathogens. Apart from their apparent role in innate immunity, neutrophils also orchestrate subsequent adaptive immune responses during infection. Thus, the outcome of pulmonary infections can be shaped by neutrophils. This review summarizes the age-driven impairment of neutrophil responses and the contribution of these cells to the susceptibility of the elderly to pneumonia. We describe how aging is accompanied by changes in neutrophil recruitment, resolution, and function. We discuss how systemic and local changes alter the neutrophil phenotype in aged hosts. We highlight the gap in knowledge of whether these changes in neutrophils also contribute to the decline in adaptive immunity seen with age. We further detail the factors that drive dysregulated neutrophil responses in the elderly and the pathways that may be targeted to rebalance neutrophil activity and boost host resistance to pulmonary infections.

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.

Overcoming immune dysfunction in the elderly: trained immunity as a novel approach

People with advanced age have a higher susceptibility to infections and exhibit increased mortality and morbidity as the ability of the immune system to combat infections decreases with age. While innate immune cells display functional defects such as decreased phagocytosis, chemotaxis and cytokine production, adaptive immune cells exhibit reduced receptor diversity, defective antibody production and a sharp decline in naive cell populations. Successful responses to vaccination in the elderly are critical to prevent common infections such as influenza and pneumonia, but vaccine efficacy decreases in older individuals compared with young adults. Trained immunity is a newly emerging concept that showed that innate immune cells possess non-specific immunological memory established through epigenetic and metabolic reprogramming upon encountering certain pathogenic stimuli. Clinical studies suggest that trained immunity can be utilized to enhance immune responses against infections and improve the efficiency of vaccinations in adults; however, how trained immunity responses are shaped with advanced age is still an open question. In this review, we provide an overview of the age-related changes in the immune system with a focus on innate immunity, discuss current vaccination strategies for the elderly, present the concept of trained immunity and propose it as a novel approach to enhance responses against infections and vaccinations in the elderly population.

Oxidative stress and exceptional human longevity: Systematic review

OBJECTIVE

Oxidative stress (OS) has been previously linked to the aging process, as have some diseases and geriatric syndromes as frailty and sarcopenia. The aim of the present study was to perform a systematic review on oxidative stress activity and extreme longevity in humans.

METHODS

We conducted a systematic literature review following the PRISMA guidelines. Observational studies assessing OS-biomarkers and/or antioxidants in long-lived individuals (97 years old or over) comparing them to those of one or more age groups, (at least one of which from comprising elderly subjects) were considered for inclusion. A narrative synthesis was planned. Quality of selected studies was assessed using the Newcastle-Ottawa quality assessment scale (NOS).

RESULTS

After screening and eligibility phases, 12 articles were finally selected, with 646 long-lived participants and 1052 controls, 447 adults (20-60 years old) and 605 elderly individuals (over 60 years old). The average score on NOS scale of studies was 4,8 out of 9. Centenarians showed significantly less (p<0,05) oxidative damage to lipids in different samples, lower levels of oxidized proteins in plasma and lower superoxide anion levels in neutrophils than elderly groups. Centenarian presented significantly lower superoxide dismutase and higher glutathione reductase activities, higher levels of vitamins A and E, lower of coenzyme Q10, and lower susceptibility to lipid peroxidation than elderly controls.

CONCLUSION

Based on studies of medium-low quality, available evidence suggests that long-lived individuals display less oxidative damage, particularly lower plasma lipid peroxidation biomarkers, than controls. More studies with better experimental designs are needed.

Inflamm-Aging Is Associated with Lower Plasma PTX3 Concentrations and an Impaired Capacity of PBMCs to Express hTERT following LPS Stimulation

Age-related elevations in proinflammatory cytokines, known as inflamm-aging, are associated with shorter immune cell telomere lengths. Purpose. This study examined the relationship of plasma PTX3 concentrations, a biomarker of appropriate immune function, with telomere length in 15 middle-aged (40-64 years) and 15 young adults (20-31 years). In addition, PBMCs were isolated from middle-aged and young adults to examine their capacity to express a key mechanistic component of telomere length maintenance, human telomerase reverse transcriptase (hTERT), following ex vivo cellular stimulation. Methods. Plasma PTX3 and inflammatory cytokines (i.e., IL-6, IL-10, TGF-β, and TNF-α), PBMC telomere lengths, and PBMC hTERT gene expression and inflammatory protein secretion following exposure to LPS, PTX3, and PTX3+LPS were measured. Results. Aging was accompanied by the accumulation of centrally located visceral adipose tissue, without changes in body weight and BMI, and alterations in the systemic inflammatory milieu (decreased plasma PTX3 and TGF-β; increased TNF-α (p ≤ 0.050)). In addition, shorter telomere lengths in middle-aged compared to young adults (p = 0.011) were negatively associated with age, body fat percentages, and plasma TNF-α (r = −0.404, p = 0.027; r = −0.427, p = 0.019; and r = −0.323, p = 0.041, respectively). Finally, the capacity of PBMCs to increase hTERT gene expression following ex vivo stimulation was impaired in middle-aged compared to young adults (p = 0.033) and negatively associated with telomere lengths (r = 0.353, p = 0.028). Conclusions. Proinflammation and the impaired hTERT gene expression capacity of PBMCs may contribute to age-related telomere attrition and disease.

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.

The Confluence of Sex Hormones and Aging on Immunity

The immune systems of post-pubescent males and females differ significantly with profound consequences to health and disease. In many cases, sex-specific differences in the immune responses of young adults are also apparent in aged men and women. Moreover, as in young adults, aged women develop several late-adult onset autoimmune conditions more frequently than do men, while aged men continue to develop many cancers to a greater extent than aged women. However, sex differences in the immune systems of aged individuals have not been extensively investigated and data addressing the effectiveness of vaccinations and immunotherapies in aged men and women are scarce. In this review, we evaluate age- and sex hormone-related changes to innate and adaptive immunity, with consideration about how this impacts age- and sex-associated changes in the incidence and pathogenesis of autoimmunity and cancer as well as the efficacy of vaccination and cancer immunotherapy. We conclude that future preclinical and clinical studies should consider age and sex to better understand the ways in which these characteristics intersect with immune function and the resulting consequences for autoimmunity, cancer, and therapeutic interventions.

The potential of non-myeloablative heterochronous autologous hematopoietic stem cell transplantation for extending a healthy life span

Aging is a complex multifactorial process, a prominent component being the senescence of the immune system. Consequently, immune-related diseases develop, including atherosclerosis, cancer, and life-threatening infections, which impact on health and longevity. Rejuvenating the aged immune system could mitigate these diseases, thereby contributing to longevity and health. Currently, an appealing option for rejuvenating the immune system is heterochronous autologous hematopoietic stem cell transplantation (haHSCT), where healthy autologous bone marrow/peripheral blood stem cells are collected during the youth of an individual, cryopreserved, and re-infused when he or she has reached an older age. After infusion, young hematopoietic stem cells can reconstitute the compromised immune system and improve immune function. Several studies using animal models have achieved substantial extension of the life span of animals treated with haHSCT. Therefore, haHSCT could be regarded as a potential procedure for preventing age-related immune defects and extending healthy longevity. In this review, the pros, cons, and future feasibility of this approach are discussed.

Influence of Inflammation in the Process of T Lymphocyte Differentiation: Proliferative, Metabolic, and Oxidative Changes

T lymphocytes, from their first encounter with their specific antigen as naïve cell until the last stages of their differentiation, in a replicative state of senescence, go through a series of phases. In several of these stages, T lymphocytes are subjected to exponential growth in successive encounters with the same antigen. This entire process occurs throughout the life of a human individual and, earlier, in patients with chronic infections/pathologies through inflammatory mediators, first acutely and later in a chronic form. This process plays a fundamental role in amplifying the activating signals on T lymphocytes and directing their clonal proliferation. The mechanisms that control cell growth are high levels of telomerase activity and maintenance of telomeric length that are far superior to other cell types, as well as metabolic adaptation and redox control. Large numbers of highly differentiated memory cells are accumulated in the immunological niches where they will contribute in a significant way to increase the levels of inflammatory mediators that will perpetuate the new state at the systemic level. These levels of inflammation greatly influence the process of T lymphocyte differentiation from naïve T lymphocyte, even before, until the arrival of exhaustion or cell death. The changes observed during lymphocyte differentiation are correlated with changes in cellular metabolism and these in turn are influenced by the inflammatory state of the environment where the cell is located. Reactive oxygen species (ROS) exert a dual action in the population of T lymphocytes. Exposure to high levels of ROS decreases the capacity of activation and T lymphocyte proliferation; however, intermediate levels of oxidation are necessary for the lymphocyte activation, differentiation, and effector functions. In conclusion, we can affirm that the inflammatory levels in the environment greatly influence the differentiation and activity of T lymphocyte populations. However, little is known about the mechanisms involved in these processes. The elucidation of these mechanisms would be of great help in the advance of improvements in pathologies with a large inflammatory base such as rheumatoid arthritis, intestinal inflammatory diseases, several infectious diseases and even, cancerous processes.

Evaluation of Lymphocyte Response to the Induced Oxidative Stress in a Cohort of Ageing Subjects, including Semisupercentenarians and Their Offspring

The production of reactive oxygen species (ROS) may promote immunosenescence if not counterbalanced by the antioxidant systems. Cell membranes, proteins, and nucleic acids become the target of ROS and progressively lose their structure and functions. This process could lead to an impairment of the immune response. However, little is known about the capability of the immune cells of elderly individuals to dynamically counteract the oxidative stress. Here, the response of the main lymphocyte subsets to the induced oxidative stress in semisupercentenarians (CENT), their offspring (OFF), elderly controls (CTRL), and young individuals (YO) was analyzed using flow cytometry. The results showed that the ratio of the ROS levels between the induced and noninduced (I/NI) oxidative stress conditions was higher in CTRL and OFF than in CENT and YO, in almost all T, B, and NK subsets. Moreover, the ratio of reduced glutathione levels between I/NI conditions was higher in OFF and CENT compared to the other groups in almost all the subsets. Finally, we observed significant correlations between the response to the induced oxidative stress and the degree of methylation in specific genes on the oxidative stress pathway. Globally, these data suggest that the capability to buffer dynamic changes in the oxidative environment could be a hallmark of longevity in humans.

Human exceptional longevity: transcriptome from centenarians is distinct from septuagenarians and reveals a role of Bcl-xL in successful aging

Centenarians not only enjoy an extraordinary aging, but also show a compression of morbidity. Using functional transcriptomic analysis of peripheral blood mononuclear cells (PMBC) we identified 1721 mRNAs differentially expressed by centenarians when compared with septuagenarians and young people. Sub-network analysis led us to identify Bcl-xL as an important gene up-regulated in centenarians. It is involved in the control of apoptosis, cellular damage protection and also in modulation of immune response, all associated to healthy aging. Indeed, centenarians display lower plasma cytochrome C levels, higher mitochondrial membrane potential and also less cellular damage accumulation than septuagenarians. Leukocyte chemotaxis and NK cell activity are significantly impaired in septuagenarians compared with young people whereas centenarians maintain them. To further ascertain the functional role of Bcl-xL in cellular aging, we found that lymphocytes from septuagenarians transduced with Bcl-xL display a reduction in senescent-related markers. Finally, to demonstrate the role of Bcl-xL in longevity at the organism level, C. elegans bearing a gain of function mutation in the Bcl-xL ortholog ced-9, showed a significant increase in mean and maximal life span. These results show that mRNA expression in centenarians is unique and reveals that Bcl-xL plays an important role in exceptional aging.

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.

Inflammaging and the Lung

With the coming of the "silver tsunami," expanding the knowledge about how various intrinsic and extrinsic factors affect the immune system in the elderly is timely and of immediate clinical need. The global population is increasing in age. By the year 2030, more than 20% of the population of the United States will be older than 65 years of age. This article focuses on how advanced age alters the immune systems and how this, in turn, modulates the ability of the aging lung to deal with infectious challenges from the outside world and from within the host.

Cellular immune activation in Sardinian middle-aged, older adults and centenarians

In addition to viral infections, malignant disorders, autoimmune diseases, and allograft rejection episodes, neopterin increases in older people where it is found to be predictive of overall mortality. Thus, the serum concentrations of this biomarker of systemic immune and inflammation activation, were measured in a small cohort of Sardinian middle-aged, older adults and centenarians. There was a significant positive correlation between neopterin concentrations and age with the subjects in the 95-year-old group with the highest values. Notably, the group of centenarians had neopterin values comparable to those of 80- and 90-year-old groups, and significantly lower than that of 95-year-old group. This suggests a decreased monocyte/macrophage-mediated immune activation and an apparently preserved immune status in centenarians.

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.

Aging and cancer: The role of macrophages and neutrophils

Impaired immune function has been implicated in the declining health and higher incidence of cancer in the elderly. However, age-related changes to immunity are not completely understood. Neutrophils and macrophages represent the first line of defence yet their ability to phagocytose pathogens decrease with aging. Cytotoxic T lymphocytes are critical in eliminating tumors, but T cell function is also compromised with aging. T cell responses can be regulated by macrophages and may depend on the functional phenotype macrophages adopt in response to microenvironmental signals. This can range from pro-inflammatory, anti-tumorigenic M1 to anti-inflammatory, pro-tumorigenic M2 macrophages. Macrophages in healthy elderly adipose and hepatic tissue exhibit a more pro-inflammatory M1 phenotype compared to young hosts whilst immunosuppressive M2 macrophages increase in elderly lymphoid tissues, lung and muscle. These M2-like macrophages demonstrate altered responses to stimuli. Recent studies suggest that neutrophils also regulate T cell function and, like macrophages, neutrophil function is modulated with aging. It is possible that age-modified tissue-specific macrophages and neutrophils contribute to chronic low-grade inflammation that is associated with dysregulated macrophage-mediated immunosuppression, which together are responsible for development of multiple pathologies, including cancer. This review discusses recent advances in macrophage and neutrophil biology in healthy aging and cancer.

Aging of the immune system: Focus on inflammation and vaccination

Major advances in preventing, delaying, or curing individual pathologies are responsible for an increasingly long life span in the developed parts of our planet, and indeed reaching eight to nine decades of life is nowadays extremely frequent. However, medical and sanitary advances have not prevented or delayed the underlying cause of the disparate pathologies occurring in the elderly: aging itself. The identification of the basis of the aging processes that drives the multiple pathologies and loss of function typical of older individuals is a major challenge in current aging research. Among the possible causes, an impairment of the immune system plays a major role, and indeed numerous studies have described immunological changes which occur with age. Far from the intention of being exhaustive, this review will focus on recent advances and views on the role that modifications of cell signalling and remodelling of the immune response play during human aging and longevity, paying particular attention to phenomena which are linked to the so called inflammaging process, such as dysregulation of innate immunity, altered T-cell or B-cell maturation and differentiation, as well as to the implications of immune aging for vaccination strategies in the elderly.

Low expression of CD39 and CD73 genes in centenarians compared with octogenarians

Ageing involves a progressive decline of the body’s regulatory systems including immune system. Adenosine regulates immune function by interaction with its receptors, mainly adenosine A2A receptor, present on the surface of immune cells. Furthermore, cellular response to this nucleoside is highly dependent on its extracellular concentration that is regulated by ecto-enzymes such as CD39 and CD73. Therefore, the aim of this study was to investigate the effect of age on adenosine A2A receptor, CD39 and CD73 gene expression. Changes in mRNA were measured by quantitative PCR from peripheral blood of young, middle-aged and older adults as well as centenarians. Centenarians showed a prominent decrease of CD39 and CD73 mRNA in comparison with older adults. Regarding to adenosine A2A receptor, we detected two subgroups of centenarians with high and low level of transcript. Additionally, adenosine A2A receptor mRNA level of centenarians, did not correlate with their cognitive impairment. In summary, our pilot study suggests that unlike of adenosine A2A receptor, the level of CD39 as well as CD73 mRNA could be a hallmark of successful human ageing.

Alcohol, aging, and innate immunity

The global population is aging: in 2010, 8% of the population was older than 65 y, and that is expected to double to 16% by 2050. With advanced age comes a heightened prevalence of chronic diseases. Moreover, elderly humans fair worse after acute diseases, namely infection, leading to higher rates of infection-mediated mortality. Advanced age alters many aspects of both the innate and adaptive immune systems, leading to impaired responses to primary infection and poor development of immunologic memory. An often overlooked, yet increasingly common, behavior in older individuals is alcohol consumption. In fact, it has been estimated that >40% of older adults consume alcohol, and evidence reveals that >10% of this group is drinking more than the recommended limit by the National Institute on Alcohol Abuse and Alcoholism. Alcohol consumption, at any level, alters host immune responses, including changes in the number, phenotype, and function of innate and adaptive immune cells. Thus, understanding the effect of alcohol ingestion on the immune system of older individuals, who are already less capable of combating infection, merits further study. However, there is currently almost nothing known about how drinking alters innate immunity in older subjects, despite innate immune cells being critical for host defense, resolution of inflammation, and maintenance of immune homeostasis. Here, we review the effects of aging and alcohol consumption on innate immune cells independently and highlight the few studies that have examined the effects of alcohol ingestion in aged individuals.

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

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

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

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

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Peritoneal macrophages have higher lipofuscin levels than lymphocytes along aging.

ROS production, intracellular HSP70 levels and their relationship in human neutrophils: effects of age

ROS production and intracellular HSP70 levels were measured in human neutrophils for three age groups: young (20-59 years), elders (60-89 years) and nonagenarians (90 years and older). Elders showed higher levels of spontaneous intracellular ROS content compared with young and nonagenarian groups, which had similar intracellular ROS levels. Zymosan-induced (non-spontaneous) extracellular ROS levels were also similar for young and nonagenarians but were lower in elders. However, spontaneous extracellular ROS production increased continuously with age. Correlation analysis revealed positive relationships between HSP70 levels and zymosan-stimulated ROS production in the elder group. This was consistent with a promoting role for HSP70 in ROS-associated neutrophils response to pathogens. No positive correlation between ROS production and intracellular HSP70 levels was found for groups of young people and nonagenarians. In contrast, significant negative correlations of some ROS and HSP70 characteriscics were found for neutrophils from young people and nonagenarians. The observed difference in ROS and HSP70 correlations in elders and nonagenarians might be associated with an increased risk of mortality in older individuals less than 90 years old.

Innate immunesenescence: underlying mechanisms and clinical relevance

A well-established feature of physiological ageing is altered immune function, a phenomenon termed immunesenescence. Thought to be responsible in part for the increased incidence and severity of infection reported by older adults, as well as the age-related decline in vaccine efficacy and autoimmunity, immunesenescence affects both the innate and adaptive arms of the immune system. Whilst much is known regarding the impact of age on adaptive immunity, innate immunity has received far less attention from immune gerontologists. However, over the last decade it has become increasingly apparent that this non-specific arm of the immune response undergoes considerable functional and phenotypical alterations with age. Here, we provide a detailed overview of innate immunesenescence and its underlying molecular mechanisms, and highlight those studies whose results indicate that changes in innate immunity with age have a significant impact upon the health and well-being of older adults.

[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.

IFN production ability and healthy ageing: mixed model analysis of a 24 year longitudinal study in Japan

OBJECTIVE

To track changes in interferon (IFN) production in healthy individuals to shed light on the effect these changes have on the course of healthy ageing.

DESIGN

Study is based on data that were collected over 24 years from a cohort of individuals whose IFN-α production was quantified as a part of their annual routine health check-up.

SETTING

All individuals in this study underwent regular health check-ups at Louis Pasteur Center for Medical Research.

PARTICIPANTS

295 healthy individuals (159 males and 136 females) without a history of cancer, autoimmune diseases and hepatitis C virus (HCV) whose IFN-α production was quantified more than five times within 24 years were selected. Finally, 29 males and 4 females whose IFN-α production was quantified more than 25 times were selected and their data were analysed using a mixed model.

MAIN OUTCOME MEASURES

HVJ stimulated IFN-α  production was quantified. Healthy individual's periodical log transformed IFN-α values (y) were plotted versus age (x) and fitted to linear (y=mx+n) and quadratic formula (y=ax(2)+bx+c) expressions to reveal changes in the IFN-α  production in these healthy individuals.

RESULTS

The linear expression showed that log (IFN-α) had a slight tendency to decline (3% over 10 years). However, the quadratic formula analysis showed the quadratic expression to be more positive than negative (a concave U-shaped pattern) which means that individuals' once declining IFN production recovered as they aged.

CONCLUSIONS

Although we observed a marginal decline in IFN-α  production, we also observed that IFN production recovered even in individuals in their mid50s to early 60s. These results combined with our previous cross-sectional studies of patients with various diseases suggest that in healthy individuals, the impairment of IFN production is triggered more by the onset of disease (notwithstanding the cause) rather than by ageing.

[Changes in mental health index, serum biochemical parameters and neutrophil function after start of the wheelchair use at a nursing home in Korea]

OBJECTIVES

In Korea, long-term care insurance has been provided to the elderly since 2008. We conducted a health survey of the elderly in a nursing home in Korea from 2007 to 2010. Since the introduction of the insurance system, many of the elderly have started using wheelchairs. We aimed to determine the effect of using wheelchairs on mental health index, serum biochemical parameters, and neutrophil function.

METHODS

The subjects were 32 elderly persons (mean age: 74.44 ± 5.79 years) who could walk unaided in 2007 and were not bedridden until 2010. We classified the subjects into the walking group (subjects could walk unaided or with a cane until 2010; 10 men, 9 women) and the wheelchair group (subjects required the use of a wheelchair from 2007 to 2010; 2 men, 11 women). We determined stress score, stress tolerance, subjective well-being score in accordance with the Philadelphia Geriatric Center Morale Scale, and serum biochemical parameters. We also analyzed oxidant production and phagocytosis by neutrophils and estimated the balance between oxidant production and phagocytosis by correlation analysis.

RESULTS

Increases in the stress tolerance of the wheelchair group in 2008 and 2009 and the subjective well-being score in 2009 in the survey were observed. However, in 2010, the stress tolerance and the subjective well-being score decreased to the levels in 2007. In 2010, the levels of serum albumin and high-density lipoprotein cholesterol of the wheelchair group were significantly lower than those of the walking group, and the balance between phagocytosis and oxidant production in the wheelchair group improved.

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.

Differences according to gender and health status in CD4:CD8 ratio in a sample of community-dwelling oldest old. The OCTABAIX immune study

BACKGROUND AND AIMS

The presence of an immune-risk phenotype (IRP) has been correlated with survival rates in elderly people. The aim of this study is to characterize the inverted CD4:CD8 ratio as a possible marker of IRP in a sample of oldest old (85 years) by assessing differences in gender and health status.

METHODS

Comorbidity, functional status (Barthel Index), and cognitive status with the Spanish version of the Mini-Mental State Examination were evaluated. Non-disabled subjects were defined as those with better health status, with scores of >90 on the Barthel Index and >23 points on the Spanish version of the Mini-Mental State Examination. CD4:CD8 ratios were recorded, and a ratio of 1.00 or less was used to define IRF.

RESULTS

Three hundred and twelve subjects aged 85 years old were studied, 190 women (60.9%) and 122 men. The CD4:CD8 ratio was 1.00 or less in 47 subjects (15.6%) and higher than 2.2 in 115 (36.8%). There were no differences in CD4:CD8 ratio according to health status. The inverted CD4:CD8 ratio was more frequent in men (55.3%).

CONCLUSION

In this community-dwelling, single year birth cohort study, the subgroup with poor health status did not have a lower CD4:CD8 ratio. The inverted CD4:CD8 ratio was more frequent in men.

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

Preserved immune cell function has been reported in mice that achieve extreme longevity. Since cytokines are major modulators of immune responses, we aimed to determine the levels of 21 cytokines secreted ex vivo by peritoneal leukocytes cultured under basal- and mitogen- (conconavalin A (ConA) and LPS) stimulated conditions in middle-aged (44 ± 4 weeks), old (69 ± 4 weeks), very old (92 ± 4 weeks), and extreme long-lived (125 ± 4 weeks) ICR (CD1) female mice. The secretion of cytokines was measured by multiplex luminometry. Increased basal levels of proinflammatory IL-1β, IL-6, IL-12 (p70), IFN-γ, and TNF-α were seen in the old and very old animals, accompanied by decreased IL-10. In contrast, the extreme long-lived mice maintained the overall cytokine profile of middle-aged mice, though the basal secretion of IL-2, IL-9, IL-10, IL-13, and IL-12 (p40) was raised. Under LPS- and/or ConA-stimulated conditions, leukocytes from old and very old animals showed a significantly impaired response with respect to secretion of Th1 cytokines IL-3, IL-12p70, IFN-γ, and TNF-α; Th2 cytokines IL-6, IL-4, IL-10, and IL-13; and the regulatory cytokines IL-2, IL-5, and IL-17. Extreme long-lived mice preserved the middle-aged-like cytokine profile, with the most striking effect seen for the IL-2 response to ConA, which was minimal in the old and very old mice but increased with respect to the middle-aged level in extreme long-lived mice. Chemokine responses in regard to KC, MCP-1, MIP1β, and RANTES were more variable, though similar secretion of LPS-induced KC and MCP-1 and ConA-induced MCP-1, MIP-1β, and RANTES was found in long-lived and middle-aged mice. Thus, extreme long-lived animals showed only a minimal inflammatory profile, much lower than the old and very old groups and also lower than the middle-aged, which is likely mediated by the increase of anti-inflammatory cytokines such as IL-10. This was coupled to a robust response to immune stimuli across an appropriated Th1/Th2 and regulatory cytokine secretion, which seems to be a factor contributing to the preserved immune response reported in very long-lived animals and thus to their extended longevity.

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.

Neutrophils are immune cells preferentially targeted by retinoic acid in elderly subjects

Background

The immune system gradually deteriorates with age and nutritional status is a major factor in immunosenescence. Of the many nutritional factors implicated in age-related immune dysfunction, vitamin A may be a good candidate, since vitamin A concentrations classically decrease during aging whereas it may possess important immunomodulatory properties via its active metabolites, the retinoic acids. This prompted us to investigate the immune response induced by retinoids in adults and elderly healthy subjects. Before and after oral supplementation with 13cis retinoic acid (0.5 mg/kg/day during 28 days), whole blood cells were phenotyped, and functions of peripheral blood mononuclear cells (PBMC) and polymorphonuclear cells (PMN) were investigated by flow cytometry and ELISA tests.

Results

In both young adults (n = 20, 25 ± 4 years) and older subjects (n = 20, 65 ± 4 years), retinoic acid supplementation had no effect on the distribution of leukocyte subpopulations or on the functions of PBMC (Il-2 and sIl-2R production, membrane expression of CD25). Concerning PMN, retinoic acid induced an increase in both spontaneous migration and cell surface expression of CD11b in the two different age populations, whereas bactericidal activity and phagocytosis remained unchanged.

Conclusions

We demonstrated that retinoic acid induces the same intensity of immune response between adult and older subjects, and more specifically affects PMN functions, i.e. adhesion and migration, than PBMC functions.

Inflammation, genetic background and longevity

Ageing is an inexorable intrinsic process that affects all cells, tissues, organs and individuals. Due to a diminished homeostasis and increased organism frailty, ageing causes a reduction of the response to environmental stimuli and, in general, is associated to an increased predisposition to illness and death. Actually, it is characterized by a state of reduced ability to maintain health and general homeodynamics of the organism. A large part of the ageing phenotype is explained by an imbalance between inflammatory and anti-inflammatory networks, which results in the low grade chronic pro-inflammatory status of ageing, "inflamm-ageing". It is strictly linked to immunosenescence, and on the whole they are the major contributory factors to the increased frequency of morbidity and mortality among elderly. Inflamm-ageing is compatible with longevity; even if centenarians have an increased level of inflammatory mediators in comparison to old subjects and they are very frail, they also have high level of anti-inflammatory cytokines together with protective genotypes. Actually, data on case control studies performed in Italian centenarians suggest that a pro-inflammatory genotype is unfavourable to reach extreme longevity in good health and likely favours the onset of age-related diseases such as cardiovascular diseases and Alzheimer's disease, the leading causes of mortality and disability in the elderly. However, many associations between gene variants and longevity have been found only in Italian population. This should not be unexpected, since ageing and longevity are complex traits resulting not only and not exclusively from genetics, but rather from the interactions between genetics, environment and chance.

BELFAST nonagenarians: nature or nurture? Immunological, cardiovascular and genetic factors

Nonagenarians are the fastest growing sector of populations across Western European and the developed world. They are some of the oldest members of our societies and survivors of their generation and may help us understand how to age not only longer, but better.

The Belfast Longevity Group enlisted the help of 500 community-living, mobile, mentally competent, 'elite' nonagenarians, as part of an ongoing study of ageing. We assessed some immunological, cardiovascular, nutritional and genetic factors and some aspects of their interaction in this group of 'oldest old'.

Here we present some of the evidence related to genetic and nutritional factors which seem to be important for good quality ageing in nonagenarians from the Belfast Elderly Longitudinal Free-living Ageing STudy (BELFAST).

Aged Beagle dogs have decreased neutrophil phagocytosis and neutrophil-related gene expression compared to younger dogs

Information on aging and the innate immune response in dogs is needed in order to understand the impact of age on the innate immune system and to design diets that might improve age-associated changes in innate immunity. The purpose of this study was to investigate the effects of age on phagocytosis and antibacterial activity of peripheral blood neutrophils, and on expression levels of selected mRNA specific for neutrophil migration or killing functions. Three groups of Beagle dogs were evaluated in a cross-sectional study design: puppies less than 1 year of age (n=15), adults 1-7 years of age (n=37) and senior adults over 8 years of age (n=25). Neutrophil phagocytosis and killing of Lactococcus lactis were assessed, and the relative abundance of mRNAs for myeloperoxidase (MPO), l-selectin, interleukin-8 receptor (IL-8R) and interleukin-1beta-converting enzyme (ICE) was determined. Results showed that in Beagle dogs there is a significant effect of age on percent bacterial killing by neutrophils. Average decline in phagocytic ability at 4 and 10 years of age (compared to 1 year of age) was 25% and 39%, respectively. In addition, younger dogs have significantly higher levels of mRNA for IL-8R, l-selectin and ICE. These results suggest that older dogs have depressed innate immune responses compared with younger dogs, which may contribute to increased morbidity and mortality with aging.

Leukocyte function in the aging immune system

Aging is associated with a progressive dysregulation of immune responses. Whether these changes are solely responsible for the observed increased mortality and morbidity amongst the elderly is uncertain. Recent advances have highlighted the age-associated changes that occur beyond T and B lymphocytes. Additionally, multiple human and animal studies have identified a relationship between chronic low-grade inflammation and geriatric syndromes, such as frailty, suggesting that the phenomenon of "inflamm-aging" may provide a rationale for the increased vulnerability to chronic inflammatory diseases in older adults. In the present review, we broadly summarize our current understanding of age-dependent changes in leukocyte function and their contribution to aging-related disease processes.

Modulation of granulocyte functions by peptide YY in the rat: age-related differences in Y receptors expression and plasma dipeptidyl peptidase 4 activity

It has been acknowledged that aging exerts detrimental effects on cells of the innate immune system and that neuropeptides, including neuropeptide Y (NPY) and NPY-related peptides fine-tune the activity of these cells through a receptor specific mechanism. The present study investigated the age-dependent potential of peptide YY (PYY) to modulate different granulocyte functions. The PYY reduced the carrageenan-elicited granulocyte accumulation into the air-pouch of aged (24 months) rats, and markedly decreased the phagocytosis of zymosan, as well as the H(2)O(2) production, when applied in vivo (20 microg/air-pouch). The anti-inflammatory effect of PYY was less prominent in adult (8 months) and young (3 months) rats. However, the proportions of granulocytes expressing Y1, Y2 and Y5 receptor subtypes were significantly lower in both aged and young rats when compared to adult rats. Furthermore, the aging was found to be associated with the diminished dipeptidyl peptidase 4 (DP4, an enzyme converting the NPY and PYY to Y2/Y5 receptor selective agonists) activity in plasma. In conclusion, the diverse age-related anti-inflammatory effect of PYY in rats originates from different expression levels of Y1, Y2, and Y5 receptor subtypes in addition to different plasma DP4 activity.