Laura Bucci

Massive Load of Functional Effector CD4+ and CD8+ T Cells against Cytomegalovirus in Very Old Subjects

A progressive, systemic, and low-grade proinflammatory status is one of the major characteristics of immunosenescence. Emerging data suggest a possible contribution of CMV, known to chronically infect a large proportion of humans, lifelong from newborns to centenarians. To test this hypothesis, we evaluated functional T cell responses to two CMV immunogenic proteins, pp65 and IE-1, in 65 chronically infected subjects aged 25–100 years. PBMC were stimulated with mixtures of peptides spanning the entire sequence of both proteins, and Ag specificity and magnitude of intracellular IFN-γ- and TNF-α-positive cells were then analyzed within both CD4+ and CD8+ T cells. Results indicate that pp65 and, to a lesser extent, IE-1 constitute major Ags against which aged people target functionally efficient T cell effector responses with massive production of Th1 cytokines and exhibition of CD107a degranulation marker. As a result, the production of IFN-γ induced in T cells by both Ags was seven to eight times greater in very old than in young subjects. The comparative analysis of pp65-specific responses in these very long-term carriers revealed a reciprocal relationship between CD4+ and CD8+ producing IFN-γ in the same individuals. These results indicate that CMV represents an important pathogen responsible for a strong immune activation in human aging. Such a remarkable burden of effector CD4+ and CD8+ T cells may be necessary to protect the elderly from CMV endogenous reactivation, but can turn detrimental by giving a substantial contribution to the proinflammatory status that accompanies the main age-related diseases.

Immunosenescence and Immunogenetics of Human Longevity

At present, individuals can live up to 80–120 years, a time much longer than that of our ancestors, as a consequence of the improvements in life conditions and medical care. Thus, the human immune system has to cope with a lifelong and evolutionarily unpredicted exposure to a variety of antigens, which are at the basis of profound age-related changes globally indicated as immunosenescence, a multifaceted phenomenon that increases morbidity and mortality due to infections and age-related pathologies. The major changes occurring during immunosenescence are the result of the accumulation of cellular, molecular defects and involutive phenomena (such as thymic involution) occurring concomitantly to a hyperstimulation of both innate and adaptive immunity (accumulation of expanded clones of memory and effector T cells, shrinkage of the T cell receptor repertoire, progressive activation of macrophages), and resulting in a low-grade, chronic state of inflammation defined as inflammaging. It is unknown whether inflammaging, which represents a risk factor for most age-related pathologies, is a cause or rather an effect of the aging process. In this complex scenario, the role of genetic background likely represents a fundamental variable to attain successful aging and longevity. Accordingly, centenarians seem to be equipped with gene variants that allow them to optimize the balance between pro- and anti-inflammatory molecules, and thus to minimize the effects of the lifelong exposure to environmental insults and stressors. The remarkable features of the genetics of aging and longevity are reviewed, stressing the unexpected and unusual results obtained regarding such a postreproductive type of genetics.

Role of epigenetics in human aging and longevity: genome-wide DNA methylation profile in centenarians and centenarians' offspring.

The role of epigenetics in the modulation of longevity has not been studied in humans. To this aim, (1) we evaluated the DNA methylation from peripheral leukocytes of 21 female centenarians, their 21 female offspring, 21 offspring of both non-long-lived parents, and 21 young women through ELISA assay, pyrosequencing analysis of Alu sequences, and quantification of methylation in CpG repeats outside CpG islands; (2) we compared the DNA methylation profiles of these populations through Infinium array for genome-wide CpG methylation analysis. We observed an age-related decrease in global DNA methylation and a delay of this process in centenarians’ offspring. Interestingly, literature data suggest a link between the loss of DNA methylation observed during aging and the development of age-associated diseases. Genome-wide methylation analysis evidenced DNA methylation profiles specific for aging and longevity: (1) aging-associated DNA hypermethylation occurs predominantly in genes involved in the development of anatomical structures, organs, and multicellular organisms and in the regulation of transcription; (2) genes involved in nucleotide biosynthesis, metabolism, and control of signal transmission are differently methylated between centenarians’ offspring and offspring of both non-long-lived parents, hypothesizing a role for these genes in human longevity. Our results suggest that a better preservation of DNA methylation status, a slower cell growing/metabolism, and a better control in signal transmission through epigenetic mechanisms may be involved in the process of human longevity. These data fit well with the observations related to the beneficial effects of mild hypothyroidism and insulin-like growth factor I system impairment on the modulation of human lifespan.

Age-dependent modifications of Type 1 and Type 2 cytokines within virgin and memory CD4+ T cells in humans

Several alterations in immune function and a concomitant progressive increase in pro-inflammatory status are the major characteristics of ageing process. Cytokines play a key role during ageing acting both in regulatory communication among cells and in effector activity during an immune response. The impact of age on intracellular Type 1 (IFN-gamma and TNF-alpha) and Type 2 (IL-4) cytokines, after stimulation with PMA/ionomycin, was determined in three CD4+ T subsets, i.e. CD95- CD28+ (virgin), CD95+ CD28+ (activated/memory), and CD95+ CD28- (effector/memory) from 47 subjects aged between 21 and 99 years. The percentage of IFN-gamma positive cells significantly decreased in virgin CD4+ subset both in old and nonagenarian subjects, as well as in activated/memory T cells from old in comparison with young subjects. The percentage of TNF-alpha positive cells significantly decreased in activated/memory CD4+ subset from old people. Regarding Type 2 cytokines, IL-4 positive cells significantly increased in activated/memory CD4+ subset from nonagenarians. On the whole our data indicate that: (1) different Type 1 and Type 2 cytokine-positive CD4+ T subsets are differently affected by ageing process; (2) activated/memory T cells appear to be the most affected subset; (3) a shift towards an increased role of Type 2 cytokines and a diminished role of Type 1 cytokines emerges with ageing.

Immune System, Cell Senescence, Aging and Longevity - Inflamm-Aging Reappraised

Inflamm-aging, that is the age-associated inflammatory status, is considered one of the most striking consequences of immunosenescence, as it is believed to be linked to the majority of age-associated diseases sharing an inflammatory basis. Nevertheless, evidence is emerging that inflamm-aging is at least in part independent from immunological stimuli. Moreover, centenarians who avoided or delayed major inflammatory diseases display markers of inflammation. In this paper we proposed a reappraisal of the concept of inflamm-aging, suggesting that its pathological effects can be independent from the total amount of pro-inflammatory mediators, but they would be rather associated with the anatomical district and type of cells where they are produced and where they primarily act.

Intense Antiextracellular Adaptive Immune Response to Human Cytomegalovirus in Very Old Subjects with Impaired Health and Cognitive and Functional Status

Human aging is characterized by expanded and altered adaptive immune responses to human CMV (HCMV). It is unclear whether this expansion has its origins in age-related homeostatic disturbances or viral reactivation, whether anti-CMV immune surveillance may still be effective, and what are the consequences of this expanded immune response for health and longevity. We conducted an observational cross-sectional study in groups of HCMV-seropositive subjects aged ≥65 y of variable health status to compare the intensity of Ab responses against HCMV with those against EBV and with CD4+ and CD8+ T cell proinflammatory effector responses directed to HCMV-derived pp65 and immediate-early protein 1 synthetic peptides. Ab responses to HCMV, but not to EBV, and anti-HCMV CD4+, but not CD8+, T cell responses were more intense in elderly subjects aged ≥85 y in poor health and were inversely correlated with markers of functional activity and cognitive function. Therefore, humoral and CD4+ T cell anti-HCMV responses were specifically intensified in advanced aging associated with comorbidity and cognitive and functional impairments. Such a distinctive pattern of adaptive immunity indicates that immune responses targeting the extracellular phase of HCMV are increased in these elderly subjects and could represent an indirect effect of localized and undetectable HCMV reactivation. This study demonstrates that the oldest subjects in poor health with physical and mental impairment express intense functional immune responses to extracellular HCMV and suggests that they may be at risk for direct pathogenic effects by HCMV reactivation as well as indirect pathogenic effects linked to proinflammatory anti-HCMV effector responses.

Why do centenarians escape or postpone cancer? The role of IGF-1, inflammation and p53

BackgroundCentenarians are exceptionally long living individuals who escaped the most common age-related diseases. In particular they appear to be effectively protected from cancers. The mechanisms that underlie this protection are quite complex and still largely unclear.AimTo critically analyse the literature in order to propose a unifying hypothesis that can account for this cancer protection in centenarians.MethodsReview of the scientific literature regarding three main players in tumourigenesis such as IGF-1, inflammation and p53, and centenarians.ResultsCentenarians appear to be characterised by low IGF-1-mediated responses and high levels of anti-inflammatory cytokines such as IL-10 and TGF-β, a condition that results in protection from cancer. Both inflammation and IGF-1 pathway converge on the tumour suppressor p53. Accordingly, some studies indicate that genetic variants of p53 are associated with human longevity by providing protection from cancer mortality.ConclusionsThe available data let us to hypothesise that among other possible mechanisms, well-preserved p53-mediated responses are likely a key factor contributing to protection from cancer in centenarians.

Hepatocellular carcinoma recurrence in patients with curative resection or ablation: impact of HCV eradication does not depend on the use of interferon

In HCV‐infected cirrhotic patients with successfully treated early hepatocellular carcinoma (HCC), the time to HCC recurrence and the effects of sustained viral eradication (SVR) by interferon (IFN)‐based or IFN‐free regimens on HCC recurrence remain unclear.

Immune parameters identify Italian centenarians with a longer five-year survival independent of their health and functional status

Centenarians are rare and exceptional individuals characterized by a peculiar phenotype. They are the best example of healthy aging in humans as most of them have escaped or substantially delayed the onset of major age-related diseases. Within this scenario, the purpose of the present work was to understand if immune status is associated with survival and health status in centenarians. To this aim, 116 centenarians were concomitantly characterized for their immunological, health and functional status, and followed-up for five-year survival. On the basis of previous knowledge we focused on a core of fundamental and basic immune parameters (number of leukocytes, monocytes, total lymphocytes, CD3(+) T lymphocytes, CD4(+) helper T lymphocytes, CD8(+) cytotoxic T lymphocytes, CD19(+) B lymphocytes and plasma levels of IgM), and the most important findings can be summarized as follows: i. a hierarchical cluster analysis was able to define Cluster1 (88 centenarians) and Cluster2 (28 centenarians) characterized by low and high values of all these immune parameters, respectively; ii. centenarians of Cluster2 showed a statistically longer five-year survival and more favorable values of other important immune (naïve, activated/memory and effector/memory T cells) and metabolic (glycemia, insulin and HOMA-IR) parameters, in accord with previous observations that centenarians have a peculiar immune profile, a preserved insulin pathway and a lower incidence of type 2 diabetes; and iii. unexpectedly, parameters related to frailty, as well as functional and cognitive status, did not show any significant correlation with the immune clustering, despite being capable per se of predicting survival. In conclusion, high values of basic immunological parameters and important T cell subsets correlate with five-year survival in centenarians, independent of other phenotypic characteristics. This unexpected biological scenario is compatible with the general hypothesis that in centenarians a progressive disconnection and loss of biological coherence among the different functions of the body occur, where survival/mortality result from the failure of any of these domains which apparently follow an independent age-related trajectory.

Hepatic decompensation is the major driver of death in HCV-infected cirrhotic patients with successfully treated early hepatocellular carcinoma

BACKGROUND & AIMS Assessment of long-term outcome is required in hepatitis C virus (HCV)-infected patients with cirrhosis, who have been successfully treated for Barcelona Clinic Liver Cancer (BCLC) stage A hepatocellular carcinoma (HCC). However, problems arise due to the lack of models accounting for early changes during follow-up. The aim of this study was to estimate the impact of early events (HCC recurrence or hepatic decompensation within 12months of complete radiological response) on 5-year overall survival (OS) in a large cohort of patients with HCV and cirrhosis, successfully treated HCC. METHODS A total of 328 consecutive Caucasian patients with HCV-related cirrhosis and BCLC stage 0/A HCC who had complete radiological response after curative resection or thermal ablation were prospectively recruited to this study. Primary endpoint of the study was 5-year OS. Independent baseline and time-dependent predictors of 5-year OS were identified by Cox model. RESULTS The observed 5-year survival rate was 44%. The observed HCC early recurrence and early hepatic decompensation rate were 21% and 10%, respectively. Early hepatic decompensation (Hazard Ratio [HR] 7.52; 95% confidence intervals (CI): 1.23-13.48) and HCC early recurrence as time-dependent covariates (HR 2.50; 95%CI: 1.23-5.05), presence of esophageal varices at baseline (HR 1.66; 95% CI: 1.02-2.70) and age (HR 1.04; 95% CI: 1.02-1.07) were significantly associated with the 5-year OS. CONCLUSION Survival in HCV-infected patients with cirrhosis and successfully treated HCC is influenced by early hepatic decompensation. Our study indirectly suggests that direct-acting antiviral agents could improve OS of HCC patients through long-term preservation of liver function, resulting in a lower cirrhosis-related mortality and a greater change of receiving curative treatments. LAY SUMMARY Survival in hepatitis C virus (HCV) infected patients with cirrhosis and successfully treated hepatocellular carcinoma (HCC), is mainly influenced by early hepatic decompensation. HCV eradication after treatment with new direct-acting antiviral agents could improve overall survival of HCC patients through long-term preservation of liver function.