Immunosenescence of ageing

Pediatric Helicobacter pylori infection and circulating T-lymphocyte activation and differentiation

BACKGROUND

In this study, H. pylori-infected and noninfected children with gastritis were compared to a control group with respect to circulating CD4(+) and CD8(+) T lymphocytes expressing activation and differentiation markers. Additionally, the lymphocyte phenotypes of children with gastritis were correlated with the gastric inflammation scores.

MATERIALS AND METHODS

H. pylori infection status was assessed based on [¹³C]urea breath test, rapid urease test, and histology. Analysis of the lymphocyte surface molecule expression was carried out by triple-color flow cytometry.

RESULTS

The group of H. pylori-infected children showed an elevated proportion of peripheral B cells with CD19(low) , along with a twofold increase in the percentage of memory (CD45RO(+)) CD4(+) and CD8(+) T-cell subsets (p < .05). Moreover, a positive correlation between the age and the percentage of these subsets was seen (r = .38, p = .04 and r = .56, p < .01, respectively). Children with gastritis but without infection had a slightly increased percentage of CD8(+) T cells and CD56(+) NK cells, CD3(high) T cells and CD45RO(high) CD4(+) T-cell subsets (p < .05). Both H. pylori-infected and noninfected children with gastritis were characterized by an increased percentage of memory/effector CD4(+) T cells, the presence of NK cells with CD56(high), memory T-cell subset with CD4(high), and naive, memory, memory/effector, and effector T-cell subsets with CD8(high) (p < .05). Gastric inflammation scores correlated positively with the percentage of CD4(+) T lymphocytes in H. pylori-infected children (r = .42, p = .03). In noninfected children, gastric inflammation scores correlated positively with the percentage of B cells (r = .45, p = .04).

CONCLUSION

In H. pylori-negative children, gastritis was associated with an increased percentage of activated NK and T cells, and intermediate-differentiated peripheral blood CD4(+) T cells, which was more pronounced in H. pylori-positive children who also showed an increased B-cell response. However, increased inflammation was only associated with the elevation of CD4(+) T-cell percentage in H. pylori-positive children as well as B-cell percentage in H. pylori-negative children with gastritis.

Ewing sarcoma gene Ews regulates hematopoietic stem cell senescence

The longevity of organisms is maintained by stem cells. If an organism loses the ability to maintain a balance between quiescence and differentiation in the stem/progenitor cell compartment due to aging and/or stress, this may result in death or age-associated diseases, including cancer. Ewing sarcoma is the most lethal bone tumor in young patients and arises from primitive stem cells. Here, we demonstrated that endogenous Ewing sarcoma gene (Ews) is indispensable for stem cell quiescence, and that the ablation of Ews promotes the early onset of senescence in hematopoietic stem progenitor cells. The phenotypic and functional changes in Ews-deficient stem cells were accompanied by an increase in senescence-associated β-galactosidase staining and a marked induction of p16(INK4a) compared with wild-type counterparts. With its relevance to cancer and possibly aging, EWS is likely to play a significant role in maintaining the functional capacity of stem cells and may provide further insight into the complexity of Ewing sarcoma in the context of stem cells.

Diminished cytokines gene expression in lymphoid organs of healthy aged rats

Immunuosenescence-related dysregulation of cytokine production is not fully understood and the roles of cytokines in organ aging have been insufficiently studied. This work aimed to compare the expression of interleukin-2 (IL-2), IL-4, IL-6, interferon-gamma (IFNγ), and transforming growth factor-beta (TGFβ) in lymphoid organs of young (3 months; n = 10), adult (1 year; n = 10), and aged (2 years; n = 7) rats under healthy, steady-state conditions. Cytokine mRNA levels were determined with TaqMan real-time PCR. In the spleen, all cytokine expression gradually declined with age (for representative cytokine IL-2 averages dCt in spleens of 3 months, 1 year and 2 years rats were 13,645, 13,19 and 15,470, respectively). In lymph nodes, all cytokines except TGF-β showed markedly upregulated expression in adult compared to young rats, but all were expressed at very low levels in aged rats. In bone marrow, adult animals showed enhanced IL-2, IFNγ, and TGFβ expression, but similar IL-4 and IL-6 expression, compared to young rats. Bone marrow of aged rats showed very low expression of all the measured cytokines. Our results demonstrated that changes occurred unevenly with aging in different immune system compartments.

Thymic involution: where endocrinology meets immunology

The decline in immune function with aging represents a major clinical challenge in many disease conditions. It is manifest in many parameters but is essentially linked to the adaptive immune responses. The prediction would be that abnormalities in both T and B lymphocytes underlie the loss of cellular and humoral capacity, respectively. Somewhat surprisingly, this is not reflected in numerical losses but more in alterations at the population and single cell levels. There is a major reduction in naïve T cells with a proportional increase in memory cells, and also a generally reduced function of these cells. While bone marrow function reduces with age, the most obvious reason for the T cell defects is the severe atrophy of the thymus. This is closely aligned with puberty, thereby implicating a major aetiological role for sex steroids in both thymus and immune system deterioration with age. Accordingly surgical or chemical castration (utilizing luteinizing hormone-releasing hormone) blocks sex steroids resulting in profound rejuvenation of the immune system.

Vitamin E and immunity

Vitamin E is the most important chain-breaking, lipid-soluble antioxidant present in body tissues of all cells and is considered the first line of defense against lipid peroxidation and it is important for normal function of the immune cells. However, vitamin E deficiency is rare in well-nourished healthy subjects and is not a problem, even among people living on relatively poor diets, both T- and B-cell functions are impaired by vitamin E deficiency. While immune cells are particularly enriched in vitamin E because of their high polyunsaturated fatty acid content, this point puts them at especially high risk for oxidative damage. Besides its immunomodulatory effects, vitamin E also plays an important role in carcinogenesis with its antioxidant properties against cancer, and ischemic heart disease with limiting the progression of atherosclerosis. Supplementation of vitamin E significantly enhances both cell mediated and humoral immune functions in humans, especially in the elderly and animals.

Aging and HIV infection

INTRODUCTION

Population aging has become a global phenomenon, and HIV infection among older individuals is also increasing. Because age can affect the progression of HIV infection, we aimed to evaluate the present knowledge on HIV infection in older patients.

METHODS

Literature review of the last 20 years.

RESULTS

Older HIV-infected patients have lower CD4(+) T cell counts, higher viral load and are more frequently symptomatic at diagnosis. The infection progresses more rapidly, with higher morbidity and lethality rates. However, older patients are more compliant to antiretroviral treatment; they experience a better virologic response, and treatment represents a positive clinical impact. Aging affects the complex interaction between HIV infection and the immune system. Both conditions contribute to the dysfunction of immune cells, including a decrease in the phagocytes' microbicidal capability, natural killer cells' cytolytic function, expression of toll-like receptors and production of interleukin-12. Chronic immune activation responsible for the depletion of CD4(+) and CD8(+) T cells in HIV infection appears to worsen with senescence. Older patients also exhibit a less robust humoral response, with the production of less avid and specific antibodies.

CONCLUSION

Both HIV and aging contribute to immune dysfunction, morbidity and mortality. However, highly active antiretroviral therapy (HAART) is beneficial for older patients, and treatment of older patients should not be discouraged.

Insulin effect on glucose transport in thymocytes and splenocytes from rats with metabolic syndrome

Metabolic syndrome (MS) may comprise several clinical conditions such as obesity, diabetes and inflammatory disorders, which are characterized by metabolic imbalances. The study of glucose transport and regulation by insulin in lymphocytes is important, since the way they increase inflammation and susceptibility to infections are common in MS. We studied glucose internalization in isolated thymocytes and splenocytes, its regulation by insulin, and the role of three glucose transporters (Gluts) in control and in MS rats. Control glucose internalization and insulin responses were lower in splenocytes than in thymocytes. Control and insulin-induced glucose internalization in thymocytes declined with age, while transport by splenocyte continued to respond to insulin. Control thymocyte glucose internalization was blocked by antibodies against Glut 1 and 4, while the insulin response also was blocked by an anti-Glut 3 antibody. On four month old control and insulin-induced response, splenocyte transport was only blocked by Glut 1 and 4 antibodies. At six months splenocyte glucose internalization depended on Glut 1 and was less sensitive to the effects of an anti-Glut 4 antibody. In MS splenocytes the capacity of anti-Glut 1 antibodies to inhibit control and insulin-dependent glucose transport was less significant, and we found that in MS rats, glucose internalization was dependent on Glut 3 and Glut 4. In summary, the altered metabolic state present in MS rats shows signs of modulation of glucose internalization by the Glut1, Glut 3 and Glut 4 transporters, compared with its own age control.

Successful vaccination strategies that protect aged mice from lethal challenge from influenza virus and heterologous severe acute respiratory syndrome coronavirus

Newly emerging viruses often circulate as a heterogeneous swarm in wild animal reservoirs prior to their emergence in humans, and their antigenic identities are often unknown until an outbreak situation. The newly emerging severe acute respiratory syndrome coronavirus (SARS-CoV) and reemerging influenza virus cause disproportionate disease in the aged, who are also notoriously difficult to successfully vaccinate, likely due to immunosenescence. To protect against future emerging strains, vaccine platforms should induce broad cross-reactive immunity that is sufficient to protect from homologous and heterologous challenge in all ages. From initial studies, we hypothesized that attenuated Venezuelan equine encephalitis virus (VEE) replicon particle (VRP) vaccine glycoproteins mediated vaccine failure in the aged. We then compared the efficacies of vaccines bearing attenuated (VRP(3014)) or wild-type VEE glycoproteins (VRP(3000)) in young and aged mice within novel models of severe SARS-CoV pathogenesis. Aged animals receiving VRP(3000)-based vaccines were protected from SARS-CoV disease, while animals receiving the VRP(3014)-based vaccines were not. The superior protection for the aged observed with VRP(3000)-based vaccines was confirmed in a lethal influenza virus challenge model. While the VRP(3000) vaccine's immune responses in the aged were sufficient to protect against lethal homologous and heterologous challenge, our data suggest that innate defects within the VRP(3014) platform mediate vaccine failure. Exploration into the mechanism(s) of successful vaccination in the immunosenescent should aid in the development of successful vaccine strategies for other viral diseases disproportionately affecting the elderly, like West Nile virus, influenza virus, norovirus, or other emerging viruses of the future.

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.

Transcriptomic biomarkers of the response of hospitalized geriatric patients with infectious diseases

Background

Infectious diseases are significant causes of morbidity and mortality among elderly populations. However, the relationship between oxidative stress, immune function and inflammatory response in acute phase of the infectious disease is poorly understood.

Results

Herein the abundance of a selection of 148 transcripts involved in immunosenescence and stress response was compared in total RNA of PBMC of 28 healthy aged probands and 39 aged patients in acute phase of infectious disease (day 2-4 after hospitalization) or in convalescence phase (day 7-10). This study provides a list of 24 differentially abundant transcript species in the acute phase versus healthy aged. For instance, transcripts associated with inflammatory and anti-inflammatory reactions (TNFRSF1A, IL1R1, IL1R2, IL10RB) and with oxidative stress (HMOX1, GPX1, SOD2, PRDX6) were more abundant while those associated with T-cell functions (CD28, CD69, LCK) were less abundant in acute phase. The abundance of seven of these transcripts (CD28, CD69, LCK, CTSD, HMOX1, TNFRSF1A and PRDX6) was already known to be altered in healthy aged probands compared to healthy young ones and was further affected in aged patients in acute phase, compromising an efficient response.

Conclusion

This work provides insights of the state of acute phase response to infections in elderly patients and could explain further the lack of appropriate response in the elderly compared to younger persons.

Patients with late-adult-onset ulcerative colitis have better outcomes than those with early onset disease

BACKGROUND & AIMS

The influence of age on the presentation, clinical course, and therapeutic response of patients with adult-onset ulcerative colitis (UC) is understudied. Given potential age-related differences in risk factors and immune function, we sought to determine if disease behavior or clinical outcomes differed between patients diagnosed with UC in later versus earlier stages of adulthood.

METHODS

We performed a retrospective cohort study of 295 patients with UC seen at a tertiary care center from 2001 to 2008. Adult subjects newly diagnosed with UC between the ages of 18 and 30 years were defined as early onset, those newly diagnosed at age 50 or older were defined as late onset. The 2 groups were analyzed for differences in medication use and clinical end points, including disease extent, severity at the time of diagnosis, and steroid-free clinical remission at 1 year after disease onset.

RESULTS

Disease extent and symptom severity were similar between groups at the time of diagnosis. One year after diagnosis, more patients in the late-onset group achieved steroid-free clinical remission (64% vs 49%; P = .01). Among those who required systemic steroid therapy, more late-onset patients achieved steroid-free remission by 1 year (50% vs 32%; P = .01). Former smoking status was a more common risk factor in the late-onset cohort (P < .001), whereas more early onset patients had a positive family history (P = .008).

CONCLUSIONS

Patients with early and late-adult-onset UC have similar initial clinical presentations, but differ in disease risk factors. Late-onset patients have better responses to therapy 1 year after diagnosis.

Relationship of basal heart rate variability to in vivo cytokine responses after endotoxin exposure

Autonomic inputs from the sympathetic and parasympathetic nervous systems, as measured by heart rate variability (HRV), have been reported to correlate to the severity injury and responses to infectious challenge among critically ill patients. In addition, parasympathetic/vagal activity has been shown experimentally to exert anti-inflammatory effects via attenuation of splanchnic tissue TNF-alpha production. We sought to define the influence of gender on HRV responses to in vivo endotoxin challenge in healthy humans and to determine if baseline HRV parameters correlated with endotoxin-mediated circulating cytokine responses. Young (<30 years of age), healthy subjects (n = 30) received endotoxin (2 ng/kg), and HRV and blood samples were obtained serially thereafter. Plasma cytokines were measured by enzyme-linked immunosorbent assay, and HRV parameters were determined by analysis of serial 5-min epochs of heart rate monitoring. In addition, calculation of multiscale entropy deriving from cardiac monitoring data was performed. The influence of factors such as gender, body mass index, and resting heart rate on HRV after endotoxin exposure was assessed. We found that gender, body mass index, or resting heart rate did not significantly alter the HRV response after endotoxin exposure. Using entropy analysis, we observed that females had significantly higher entropy values at 24 h after endotoxin exposure. Using a serially sampling protocol for cytokine determination, we found a significant correlation of several baseline HRV parameters (percentage of interval differences of successive interbeat intervals more than 50 ms, r = 0.42, P < 0.05; high-frequency variability, r = 0.4, P < 0.05; and low-frequency/high-frequency ratio, r = -0.43, P < 0.05) on TNF-alpha release after endotoxin exposure.

Factors that may impact on immunosenescence: an appraisal

The increasing ratio of ageing population poses new challenges to healthcare systems. The elderly frequently suffer from severe infections. Vaccination could protect them against several infectious diseases, but it can be effective only if cells that are capable of responding are still present in the repertoire. Recent vaccination strategies in the elderly might achieve low effectiveness due to age-related immune impairment. Immunosenescence affects both the innate and adaptive immunity.Beside individual variations of genetic predisposition, epigenetic changes over the full course of human life exert immunomodulating effects. Disturbances in macrophage-derived cytokine release and reduction of the natural killer cell mediated cytotoxicity lead to increased frequency of infections. Ageing dampens the ability of B cells to produce antibodies against novel antigens. Exhausted memory B lymphocyte subsets replace naïve cells. Decline of cell-mediated immunity is the consequence of multiple changes, including thymic atrophy, reduced output of new T lymphocytes, accumulation of anergic memory cells, and deficiencies in cytokines production. Persistent viral and parasitic infections contribute to the loss of immunosurveillance and premature exhaustion of T cells. Reduced telomerase activity and Toll-like receptor expression can be improved by chemotherapy. Reversion of thymic atrophy could be achieved by thymus transplantation, depletion of accumulated dysfunctional naive T cells and herpesvirus-specific exhausted memory cells. Administration of interleukin (IL)-2, IL-7, IL-10, keratinocyte growth factor, thymic stromal lymphopoietin, as well as leptin and growth hormone boost thymopoiesis. In animals, several strategies have been explored to produce superior vaccines. Among them, virosomal vaccines containing polypeptide antigens or DNA plasmids as well as new adjuvanted vaccine formulations elicit higher dendritic cell activity and more effective serologic than conventional vaccines responses in the elderly. Hopefully, at least some of these approaches can be translated to human medicine in a not too far future.

Declining expression of a single epithelial cell-autonomous gene accelerates age-related thymic involution

Age-related thymic involution may be triggered by gene expression changes in lymphohematopoietic and/or nonhematopoietic thymic epithelial cells (TECs). The role of epithelial cell-autonomous gene FoxN1 may be involved in the process, but it is still a puzzle because of the shortage of evidence from gradual loss-of-function and exogenous gain-of-function studies. Using our recently generated loxP-floxed-FoxN1(fx) mouse carrying the ubiquitous CreER(T) (uCreER(T)) transgene with a low dose of spontaneous activation, which causes gradual FoxN1 deletion with age, we found that the uCreER(T)-fx/fx mice showed an accelerated age-related thymic involution owing to progressive loss of FoxN1(+) TECs. The thymic aging phenotypes were clearly observable as early as at 3-6 months of age, resembling the naturally aged (18-22-month-old) murine thymus. By intrathymically supplying aged wild-type mice with exogenous FoxN1-cDNA, thymic involution and defective peripheral CD4(+) T-cell function could be partially rescued. The results support the notion that decline of a single epithelial cell-autonomous gene FoxN1 levels with age causes primary deterioration in TECs followed by impairment of the total postnatal thymic microenvironment, and potentially triggers age-related thymic involution in mice.

Age-related changes in plasma concentrations of the HIV protease inhibitor lopinavir

The advent of highly active antiretroviral therapy in the treatment of HIV disease has substantially extended the lifespan of individuals infected with HIV resulting in a growing population of older HIV-infected individuals. The efficacy and safety of antiretroviral agents in the population are important concerns. There have been relatively few studies assessing antiretroviral pharmacokinetics in older patients. Thirty-seven subjects aged 18-30 years and 40 subjects aged 45-79 years, naive to antiretroviral therapy, received lopinavir/ritonavir (400/100) bid, emtricitibine 200 mg qd, and stavudine 40 mg bid. Trough lopinavir concentrations were available for 44 subjects, collected at 24, 36, and 96 weeks. At week 24, older age was associated with higher lopinavir trough concentrations, and a trend was observed toward older age being associated with higher lopinavir trough concentrations when all time points were evaluated. In the young cohort, among subjects with two or more measurements, there was a trend toward increasing intrasubject trough lopinavir concentrations over time. Using a nonlinear, mixed-effects population pharmacokinetic model, age was negatively associated with lopinavir clearance after adjusting for adherence. Adherence was assessed by patient self-reports; older patients missed fewer doses than younger patients (p = 0.02). No difference in grade 3-4 toxicities was observed between the two age group. Older patients have higher trough lopinavir concentrations and likely decreased lopinavir clearance. Age-related changes in the pharmacokinetics of antiretroviral drugs may be of increasing importance as the HIV-infected population ages and as older individuals comprise an increasing proportion of new diagnoses.

Natural killer cell cytotoxicity and lymphocyte perforin expression in veterans with posttraumatic stress disorder

OBJECTIVE

To examine the effect of posttraumatic stress disorder (PTSD) on the measures of immune function and the hypothalamic-pituitary-adrenal axis components, and to determine whether additional life stressors affect measured variables.

METHODS

We simultaneously examined the natural killer cell cytotoxicity (NKCC), perforin and glucocorticoid receptor (GCR) expression in natural killer (NK) and cytotoxic T (CD8) cells, as well as serum cortisol concentration in a group of Croatian war veterans with chronic, combat-related PTSD (n=29) and a group of healthy, age-matched men (n=13). PTSD patients were divided into two subgroups: compensation-seeking (n=15) and retired or compensation non-seeking (n=14) subjects. The former includes those involved in the process of getting disability-based army retirement as an additional life stressor.

RESULTS

NKCC was decreased in both PTSD groups when compared to controls. Impairment of NKCC could not be attributed to the perforin expression as perforin was not decreased in comparison to controls. Moreover, the increased level of perforin was recorded in NK cells of retired PTSD subjects. Both PTSD groups shared an increased relative quantity of GCR in lymphocytes, whereas no difference between the groups in the baseline levels of serum cortisol was observed.

CONCLUSIONS

Diminished NKCC was not accompanied by perforin insufficiency in PTSD subjects, and other causes should be examined. An additional life stressor does not contribute considerably to either immune or endocrine system related changes.

Workshop on immunizations in older adults: identifying future research agendas

Goals for immunization in older adults may differ from those in young adults and children, in whom complete prevention of disease is the objective. Often, reduced hospitalization and death but also averting exacerbation of underlying chronic illness, functional decline, and frailty are important goals in the older age group. Because of the effect of age on dendritic cell function, T cell-mediated immune suppression, reduced proliferative capacity of T cells, and other immune responses, the efficacy of vaccines often wanes with advanced age. This article summarizes the discussion and proceedings of a workshop organized by the Association of Specialty Professors, the Infectious Diseases Society of America, the American Geriatrics Society, the National Institute on Aging, and the National Institute of Allergy and Infectious Diseases. Leading researchers and clinicians in the fields of immunology, epidemiology, infectious diseases, geriatrics, and gerontology reviewed the current status of vaccines in older adults, identified knowledge gaps, and suggest priority areas for future research. The goal of the workshop was to identify what is known about immunizations (efficacy, effect, and current schedule) in older adults and to recommend priorities for future research. Investigation in the areas identified has the potential to enhance understanding of the immune process in aging individuals, inform vaccine development, and lead to more-effective strategies to reduce the risk of vaccine-preventable illness in older adults.

Rhinitis in the geriatric population

The current geriatric population in the United States accounts for approximately 12% of the total population and is projected to reach nearly 20% (71.5 million people) by 20301. With this expansion of the number of older adults, physicians will face the common complaint of rhinitis with increasing frequency. Nasal symptoms pose a significant burden on the health of older people and require attention to improve quality of life. Several mechanisms likely underlie the pathogenesis of rhinitis in these patients, including inflammatory conditions and the influence of aging on nasal physiology, with the potential for interaction between the two. Various treatments have been proposed to manage this condition; however, more work is needed to enhance our understanding of the pathophysiology of the various forms of geriatric rhinitis and to develop more effective therapies for this important patient population.

Failure of highly active antiretroviral therapy in reconstituting immune response to Clostridium tetani vaccine in aged AIDS patients

The purpose of this study was to evaluate the impact of age on tetanus-specific immune response in successfully highly active antiretroviral therapy-treated AIDS patients, using healthy age-matched individuals as controls. Whole Peripheral blood mononuclear cells or CD8(+) cell-depleted peripheral blood mononuclear cells from previously tetanus toxoid (TT)-immunized individuals were activated with TT plus IL-2, and cell proliferation, cytokine production, and in vitro HIV-1 replication were measured. The in vivo magnitude of the humoral immune response was also assessed by antibody measurements. Our results showed that, compared with other groups, both in vitro TT-specific lymphoproliferation and serum antibody concentration were lower in older AIDS patients. Although the IL-1beta and tumour necrosis factor alpha (TNF-alpha) production were higher in cultures from aged HIV-1-infected patients, a dramatic damage on the interferon gamma (IFN-gamma) release was observed, when compared with younger patients. CD8(+) T lymphocytes depletion reduced IL-1beta and TNF-alpha release in the older groups, however, it did not significantly alter their IFN-gamma production. Furthermore, the neutralization of endogenous IL-10 did not change the IFN-gamma deficiency in older AIDS patients. Finally, the lower cellular immune response in this patient group was not related to in vitro HIV-1 replication. The results suggest that successfully highly active antiretroviral therapy-treated aged AIDS patients do not reconstitute the immune response to TT, making them probably more susceptible to tetanus even after vaccination.

Overview of the physiological changes and optimal diet in the golden age generation over 50

Basically, our lifespan is determined genetically. However, several other parameters such as the environment, lifestyle and diet have a high impact on living in the best of health. Many older persons suffer from various diseases, which often cannot be avoided; however, their development can be postponed and symptoms can be mitigated by a balanced diet, moderate physical activity as well as a healthy lifestyle. These diseases are, for example, sarcopenia (degenerative loss of muscle mass), osteoporosis (decomposition of bone structure), digestive restrictions, sensory impairment, water imbalance or a compromised immune system. Psychological modifications, obesity and loss of weight also commonly occur in older adults. To define an adequate diet for elderly between the ages 50 and 80 is difficult, even impossible, because the nutritional requirements differ between the dynamic quinquagenarian and the frailer eighty-year-old. However, several studies have shown that sufficient consumption of high-quality proteins, calcium, vitamin D, anti-oxidative food compounds, water as well as adapted energy values and nourishment with high-nutrient density in combination with physical activity especially help one to remain healthy to a great age. The cornerstone of healthy ageing is the maintenance of normal bodyweight in order to prevent the development of diseases such as osteoporosis, coronary heart disease or diabetes type 2. This publication will review the physiological changes that occur with advanced age and consequential nutritional recommendations for elderly persons.

The role of the thymus in immunosenescence: lessons from the study of thymectomized individuals

The thymus is the major site of T cell production and a key organ of the immune system. Its natural involution during the course of life has cast doubts as to its importance for the integrity of our immunity in adulthood. We provide here an overview of the recent works focusing on the immunological evaluation of subjects thymectomized during early childhood due to cardiac surgery of congenital heart defects. These studies represent new advances in our appreciation of the role of the thymus in humans and more generally in our understanding of the development of immunosenescence.

Maternal effects and early-life performance are associated with parasite resistance across life in free-living Soay sheep

Maternal effects occur when the maternal phenotype influences that of the offspring in addition to the effects of maternal genes, and may have a considerable influence on offspring parasite resistance. These effects, and the effects of early levels of reproduction and parasite resistance, may persist into later life and even influence ageing rates. Here we analyse a 20-year longitudinal data set collected on a free-living population of Soay sheep, to investigate the associations between a suite of maternal phenotypic traits and early-life performance on measures of parasite resistance across life. Our results show that maternal effects are important in determining offspring parasite resistance, since lambs born as twins and those born to the youngest and oldest mothers show higher parasite burdens. We show that the association between parasite resistance and natal litter size persists into adulthood. We also show that age-specific changes in parasite resistance in males are associated with natal litter size, and that age-specific changes in females are influenced by early-life levels of reproduction and parasite infection. These results add to the growing evidence that conditions experienced by individuals during development can have a profound influence on immediate and late-life performance and may even influence ageing.

The effect of ageing on human lymphocyte subsets: comparison of males and females

Background

There is reported to be a decline in immune function and an alteration in the frequency of circulating lymphocytes with advancing age. There are also differences in ageing and lifespan between males and females. We performed this study to see if there were differences between males and females in the frequency of the different lymphocyte subsets with age.

Results

Using flow cytometry we have examined different populations of peripheral blood leukocytes purified from healthy subjects with age ranging from the third to the tenth decade. We used linear regression analysis to determine if there is a linear relationship between age and cell frequencies. For the whole group, we find that with age there is a significant decline in the percentage of naïve T cells and CD8⁺ T cells, and an increase in the percentage of effector memory cells, CD4⁺foxp3⁺ T cells and NK cells. For all cells where there was an effect of ageing, the slope of the curve was greater for men than for women and this was statistically significant for CD8⁺αβ⁺ T cells and CD3⁺CD45RA^-CCR7^- effector memory cells. There was also a difference for naïve cells but this was not significant.

Conclusion

The cause of the change in percentage of lymphocyte subsets with age, and the different effects on males and females is not fully understood but warrants further study.

Involvement of T-cell receptor-beta alterations in the development of otosclerosis linked to OTSC2

Otosclerosis is a common form of hearing loss, characterized by disordered bone remodeling in the otic capsule. Within the otosclerotic foci, several immunocompetent cells and immune-modulating factors can be found. Different etiological theories involving the immune system have been suggested. However, a genetic component is clearly present. In large otosclerosis families, seven autosomal-dominant loci have been found, but none of the disease-causing genes has been identified. This study focused on the exploration of the second otosclerosis locus on chromosome 7q34-36 (OTSC2), holding the T-cell receptor beta locus (TRB locus). A significantly lower T-cell receptor-beta (TCR-beta) mRNA expression and percentage of blood circulating TCR-alphabeta(+) T cells was detected in OTSC2 patients compared with controls and patients with the complex form of the disease. Further analysis illustrated more significant disturbances in specific T-cell subsets, including an increased CD28(null) cell population, suggesting a disturbed T-cell development and ageing in OTSC2 patients. These disturbances could be associated with otosclerotic bone remodeling, given the known effects of immunocompetent cells on bone physiology. These data implicate the TRB locus as the causative gene in the OTSC2 region and represent an important finding in the elucidation of the disease pathology.

The evolution of an inflammatory response

BACKGROUND

The past 25 years have witnessed immense progress in our understanding of the systemic, tissue-specific, and cellular consequences of severe injury and infection. Despite such insights, considerable controversy remains regarding appropriate biologic and management interventions to prevent or ameliorate the associated adverse outcomes.

METHODS

A review of several scientific developments arising from studies initiated at Cornell University Medical College during the tenure of Dr. G. Tom Shires. The implications of those and subsequent studies are discussed.

RESULTS

An understanding of patient-specific variation and adaptability could direct individualized biologic and management interventions for severe injury and infection.

CONCLUSION

Despite more detailed appreciation of the molecular mechanisms of danger and pathogen recognition and response biology, we have much to learn about the complexity of severe injury and infection. There is a great need to extend our investigation of these mechanisms to experimental and stress-modified clinical scenarios.

Regeneration of dendritic cells in aged mice

Age-related thymic involution causes a decreased output of thymocytes from the thymus, thereby resulting in impairment of T cell-mediated immunity. While alterations in the T cell and non-haematopoietic stromal compartments have been described, the effects of thymic involution on thymic dendritic cells (DC) are not clearly known. Thymic DC play an essential role in shaping T cell-mediated immune responses by deleting self-reactive thymocytes to establish central tolerance and by inducing regulatory T-cell (Treg) development. It is therefore important to assess the prevalence of and alterations to thymic DC with age, as this may impact on their function. We assessed the numbers and proportions of the three distinct subsets of thymic DC in ageing mice, and showed that these subsets are differentially regulated. This is expected as thymic DC subsets have different origins of development. We further assessed the responses of thymic DC in a regenerative environment, such as that induced by sex-steroid ablation (SSA), and clearly showed that, consistent with global thymus regrowth, all three DC populations increased in numbers and regained their relative proportions to thymocytes after an initial lag period. These findings are important for the clinical translation of thymic regenerative approaches, and indicate that SSA facilitates the maintenance of critical processes such as negative selection and Treg induction through promoting thymic DC regeneration.

Traumatic brain injury and aging: is a combination of progesterone and vitamin D hormone a simple solution to a complex problem?

Although progress is being made in the development of new clinical treatments for traumatic brain injury (TBI), little is known about whether such treatments are effective in older patients, in whom frailty, prior medical conditions, altered metabolism, and changing sensitivity to medications all can affect outcomes following a brain injury. In this review we consider TBI to be a complex, highly variable, and systemic disorder that may require a new pharmacotherapeutic approach, one using combinations or cocktails of drugs to treat the many components of the injury cascade. We review some recent research on the role of vitamin D hormone and vitamin D deficiency in older subjects, and on the interactions of these factors with progesterone, the only treatment for TBI that has shown clinical effectiveness. Progesterone is now in phase III multicenter trial testing in the United States. We also discuss some of the potential mechanisms and pathways through which the combination of hormones may work, singly and in synergy, to enhance survival and recovery after TBI.

Regulation of cytokine signaling and T-cell recruitment in the aging mouse brain in response to central inflammatory challenge

Aging is often accompanied by increased levels of inflammatory molecules in the organism, but age-related changes in the brain response to inflammatory challenges still require clarification. We here investigated in mice whether cytokine signaling and T-cell neuroinvasion undergo age-related changes. We first analyzed the expression of molecules involved in T-cell infiltration and cytokine signaling regulation in the septum and hippocampus of 2-3 months and 20- to 24-month-old mice at 4h after intracerebroventricular injections of tumor necrosis factor (TNF)-alpha or interferon-gammaversus saline injections. Transcripts of the chemokine CXCL9, intercellular adhesion molecule (ICAM)-1 and suppressor of cytokine signaling molecules (SOCS) 1 and 3 were increased in both age groups after cytokine injection; microglia-derived matrix metalloproteinase (MMP) 12 mRNA was induced in old mice also after control saline injections. Age-related changes in ICAM-1 protein expression and T-cell infiltration were then analyzed in mice of 3-4, 8-9 and 15-16 months at 48h after TNF-alpha injections. ICAM-1 immunoreactivity, and Western blotting in striatum, septum, hippocampus and hypothalamus showed progressive age-related enhancement of TNF-alpha-elicited ICAM-1 upregulation. Double immunofluorescence revealed ICAM-1 expression in microglia and astrocytic processes. CD3(+), CD4(+) and CD8(+) T-cells exhibited progressive age-related increases in brain parenchyma and choroid plexus after cytokine exposure. The findings indicate that the brain responses to inflammatory challenges are not only preserved with advancing age, but also include gradual amplification of ICAM-1 expression and T-cell recruitment. The data highlight molecular and cellular correlates of age-related increase of brain sensitivity to inflammatory stimuli, which could be involved in altered brain vulnerability during aging.

SARS Coronavirus Pathogenesis and Therapeutic Treatment Design

Emerging pathogens are either new or newly recognized or those that are increasing in incidence and spread. Since the identity of emerging pathogens from animal reservoirs is difficult to predict, the development for pathogen-specific therapeutics and vaccines is problematic. The highly pathogenic SARS coronavirus (SARS-CoV) emerged from zoonotic pools in 2002 to cause a global epidemic of severe acute respiratory syndrome (SARS). Many patients with SARS-CoV experienced an exacerbated form of disease called acute respiratory distress syndrome (ARDS) requiring mechanical ventilation and supplemental oxygen and half of these patients died. Similar to other viral pathogens like influenza and West Nile Virus, the severity of SARS-CoV disease increased with age. Unfortunately, successful vaccination in the most vulnerable populations is a difficult task because of immunological deficiencies associated with aging (immune senescence). Due to the rapidity of virus emergence, technologies like synthetic biology can be harnessed to facilitate rapid recombinant virus construction for studying the novel virus biology, pathogenesis and the evaluation of therapeutic interventions. Since predicting the antigenic identity of future emergence is difficult, candidate vaccines and therapeutics should have a maximal breadth of cross-protection, and panels of antigenically divergent synthetically reconstructed viruses can be used as tools for this evaluation. We discuss how synthetic reconstruction of many animal and human SARS-CoV has provided a model to study the molecular mechanisms governing emergence and pathogenesis of viral diseases. In addition, we review the evolution, epidemiology, and pathogenesis of epidemic and zoonotic SARS-CoV with focus on the development of broadly reactive therapeutics and vaccines that protect aged populations from the zoonotic pool.

The epidemic of nonmelanoma skin cancer and the widespread use of statins: Is there a connection?

We hypothesize that some of the mechanisms involved in the "epidemic" of nonmelanoma skin cancer might also be due to widespread use of cholesterol lowering statin drugs.

Nutrition, geoepidemiology, and autoimmunity

As well represented by the impaired immune function of malnourished individuals encountered in developing countries and the incidence of specific diseases following local nutrient deficiencies, nutrition and immunity have been linked to each other for centuries while the specific connection between dietary factors and autoimmunity onset or modulation is a more recent acquisition. Autoimmune diseases manifest limited prevalence rates in developing countries while numerous immunity-related claims have been proposed in the field of functional foods. Nevertheless, over the past years multiple lines of evidence have supported a major role for specific dietary factors (including vitamin D, vitamin A, selenium, zinc, omega-3 fatty acids, probiotics, and flavanols) in determining the immune responses involved in infections, allergies, and autoimmune diseases. Interestingly, the link between nutrition and autoimmunity may well contribute to the geoepidemiology observed for numerous conditions. In general terms, most data that will be discussed herein were obtained in experimental or animal models while human data from real-life clinical settings or randomized clinical trials remain largely unsatisfactory. Our current knowledge on the beneficial impact of nutrition on autoimmunity prompts us to encourage the search for evidence-based nutrition to support the everyday diet choices of patients.

Immunosenescence and vaccination of the elderly II. New strategies to restore age-related immune impairment

One of the greatest health-care challenges in the elderly is to ensure that vaccination against infections are optimally effective, but vaccination can only be effective if cells that are capable of responding are still present in the repertoire. The reversing of immunosenescence could be achieved by improving immune responses or altering vaccine formulation. Recent vaccination strategies in the elderly exert low effectiveness. Nutritional interventions and moderate exercise delay T cell senescence. Telomerase activity and expression of toll-like receptors can be improved by chemotherapy. Reversion of thymic atrophy could be achieved by thymus transplantation, depletion of accumulated dysfunctional naive T cells and herpesvirus-specific exhausted memory cells. Administration of immunostimulatory and anti-inflammatory cytokines show the best practical approach. Reduced dendritic cell activity and co-receptor expression might be increased by interleukin (IL)-2 administration. IL-7 protects both B and T lymphocytes, but IL-2, IL-10, keratinocyte growth factor, thymic stromal lymphopoietin, as well as leptin and growth hormone also have a stimulatory effect on thymopoiesis. In animals, several strategies have been explored to produce more efficacious vaccines including high dose vaccines, DNA vaccines with immunostimulatory patch, virosomal vaccines and vaccines containing new adjuvants. Hopefully, one of these approaches will be translated into human therapy in a short time.

mTOR regulation and therapeutic rejuvenation of aging hematopoietic stem cells

Age-related declines in hematopoietic stem cell (HSC) function may contribute to anemia, poor response to vaccination, and tumorigenesis. Here, we show that mammalian target of rapamycin (mTOR) activity is increased in HSCs from old mice compared to those from young mice. mTOR activation through conditional deletion of Tsc1 in the HSCs of young mice mimicked the phenotype of HSCs from aged mice in various ways. These included increased abundance of the messenger RNA encoding the CDK inhibitors p16(Ink4a), p19(Arf), and p21(Cip1); a relative decrease in lymphopoiesis; and impaired capacity to reconstitute the hematopoietic system. In old mice, rapamycin increased life span, restored the self-renewal and hematopoiesis of HSCs, and enabled effective vaccination against a lethal challenge with influenza virus. Together, our data implicate mTOR signaling in HSC aging and show the potential of mTOR inhibitors for restoring hematopoiesis in the elderly.

Maintenance of naïve CD8 T cells in nonagenarians by leptin, IGFBP3 and T3

Research into the age-associated decline in the immune system has focused on the factors that contribute to the accumulation of senescent CD8 T cells. Less attention has been paid to the non-immune factors that may maintain the pool of naïve CD8 T cells. Here, we analyzed the status of the naïve CD8 T-cell population in healthy nonagenarians (>or=90-year-old), old (60-79-year-old), and young (20-34-year-old) subjects. Naïve CD8 T cells were defined as CD28(+)CD95(-) as this phenotype showed a strong co-expression of the CD45RA(+), CD45RO(-), and CD127(+) phenotypes. Although there was an age-associated decline in the percentage of CD28(+)CD95(-) CD8 T cells, the healthy nonagenarians maintained a pool of naïve CD28(+)CD95(-) cells that contained T-cell receptor excision circles (TREC)(+) cells. The percentages of naïve CD28(+)CD95(-) CD8 T cells in the nonagenarians correlated with the sera levels of insulin-like growth factor binding protein 3 (IGFBP3) and leptin. Higher levels of triiodothyronine (T3) negatively correlated with the accumulation of TREC(-)CD28(-)CD95(+) CD8 T cells from nonagenarians. These results suggest a model in which IGFBP3, leptin and T3 act as non-immune factors to maintain a larger pool of naïve CD8 T cells in healthy nonagenarians.

Effect of resistance training on hematological blood markers in older men and women: a pilot study

The aim of this study was to examine the effects of resistance training on hematological blood markers in older individuals. Twenty-nine men and women participated to this study. Subjects were randomized in 2 groups: (1) control (n = 13) and (2) resistance training (n = 16). At baseline and after the intervention, subjects were submitted to a blood sample to determine their hematological profile (red blood cells, hemoglobin, hematocrit, platelets, leukocytes, neutrophils, lymphocytes, monocytes, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width). At baseline, no difference was observed between groups. Moreover, we found no significant difference after the intervention on any of these markers. A 6-month resistance program in healthy older individuals seems to have no beneficial nor deleterious effects on hematological blood parameters. However, resistance training was well tolerated and should be recommended for other health purposes. Further studies are needed to confirm these results in a large population.

Evidence of premature immune aging in patients thymectomized during early childhood

While the thymus is known to be essential for the initial production of T cells during early life, its contribution to immune development remains a matter of debate. In fact, during cardiac surgery in newborns, the thymus is completely resected to enable better access to the heart to correct congenital heart defects, suggesting that it may be dispensable during childhood and adulthood. Here, we show that young adults thymectomized during early childhood exhibit an altered T cell compartment. Specifically, absolute CD4+ and CD8+ T cell counts were decreased, and these T cell populations showed substantial loss of naive cells and accumulation of oligoclonal memory cells. A subgroup of these young patients (22 years old) exhibited a particularly altered T cell profile that is usually seen in elderly individuals (more than 75 years old). This condition was directly related to CMV infection and the induction of strong CMV-specific T cell responses, which may exhaust the naive T cell pool in the absence of adequate T cell renewal from the thymus. Together, these marked immunological alterations are reminiscent of the immune risk phenotype, which is defined by a cluster of immune markers predictive of increased mortality in the elderly. Overall, our data highlight the importance of the thymus in maintaining the integrity of T cell immunity during adult life.