Elisa Cevenini

Inflammaging and anti-inflammaging: A systemic perspective on aging and longevity emerged from studies in humans

A large part of the aging phenotype, including immunosenescence, is explained by an imbalance between inflammatory and anti-inflammatory networks, which results in the low grade chronic pro-inflammatory status we proposed to call inflammaging. Within this perspective, healthy aging and longevity are likely the result not only of a lower propensity to mount inflammatory responses but also of efficient anti-inflammatory networks, which in normal aging fail to fully neutralize the inflammatory processes consequent to the lifelong antigenic burden and exposure to damaging agents. Such a global imbalance can be a major driving force for frailty and common age-related pathologies, and should be addressed and studied within an evolutionary-based systems biology perspective. Evidence in favor of this conceptualization largely derives from studies in humans. We thus propose that inflammaging can be flanked by anti-inflammaging as major determinants not only of immunosenescence but eventually of global aging and longevity.

Genome-wide association meta-analysis of human longevity identifies a novel locus conferring survival beyond 90 years of age

The genetic contribution to the variation in human lifespan is ∼25%. Despite the large number of identified disease-susceptibility loci, it is not known which loci influence population mortality. We performed a genome-wide association meta-analysis of 7729 long-lived individuals of European descent (≥85 years) and 16 121 younger controls (<65 years) followed by replication in an additional set of 13 060 long-lived individuals and 61 156 controls. In addition, we performed a subset analysis in cases aged ≥90 years. We observed genome-wide significant association with longevity, as reflected by survival to ages beyond 90 years, at a novel locus, rs2149954, on chromosome 5q33.3 (OR = 1.10, P = 1.74 × 10−8). We also confirmed association of rs4420638 on chromosome 19q13.32 (OR = 0.72, P = 3.40 × 10−36), representing the TOMM40/APOE/APOC1 locus. In a prospective meta-analysis (n = 34 103), the minor allele of rs2149954 (T) on chromosome 5q33.3 associates with increased survival (HR = 0.95, P = 0.003). This allele has previously been reported to associate with low blood pressure in middle age. Interestingly, the minor allele (T) associates with decreased cardiovascular mortality risk, independent of blood pressure. We report on the first GWAS-identified longevity locus on chromosome 5q33.3 influencing survival in the general European population. The minor allele of this locus associates with low blood pressure in middle age, although the contribution of this allele to survival may be less dependent on blood pressure. Hence, the pleiotropic mechanisms by which this intragenic variation contributes to lifespan regulation have to be elucidated.

Age-related differences in the expression of circulating microRNAs: miR-21 as a new circulating marker of inflammaging

Circulating microRNAs (miRs) have been investigated as diagnostic/prognostic biomarkers in human diseases. However, little is known about their expression throughout the aging process. Eleven healthy individuals aged 20, 80 and 100 years underwent miR plasma profiling. The validation cohort consisted of 111 healthy adults (CTR) aged 20-105 years and included 30 centenarians. In addition, 34 patients with cardiovascular disease (CVD) and 15 healthy centenarian offspring (CO) were enrolled. An exploratory factorial analysis grouped the miRs into three main factors: factor 1 primarily higher in 20-year-old subjects, but these differences did not reach statistical significance, factor 2 primarily higher in octogenarians and factor 3 primarily higher in centenarians. MiR-21, the most highly expressed miR of factors 2 and 3, was further validated, confirming the differences in the age groups. MiR-21 expression was higher in the CVD patients and lower in the CO compared to the age-matched CTR. MiR-21 was correlated with C-reactive protein and fibrinogen levels. TGF-β signaling was the predicted common pathway targeted by miRs of factors 2 and 3. TGF-βR2 mRNA, a validated miR-21 target, showed the highest expression in the leukocytes from a subset of the octogenarians. Our findings suggest that miR-21 may be a new biomarker of inflammation.

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.

Circulating mitochondrial DNA increases with age and is a familiar trait: Implications for “inflamm‐aging”

Mitochondrial components, including mitochondrial DNA (mtDNA), when released extracellularly, can act as “damage‐associated molecular pattern” (DAMP) agents and cause inflammation. As many elderly people are characterized by a low‐grade, chronic inflammatory status defined “inflamm‐aging,” we evaluated if circulating mtDNA can contribute to this phenomenon. Eight hundred and thirty‐one Caucasian subjects were enrolled in the study, including 429 siblings aged 90–104 (90+ siblings). mtDNA plasma levels increased gradually after the fifth decade of life. In 90+ subjects, mtDNA values of two members of the same sibling relationship were directly correlated, suggesting a role for familiar/genetic background in controlling the levels of circulating mtDNA. The subjects with the highest mtDNA plasma levels had the highest amounts of TNF‐α, IL‐6, RANTES, and IL‐1ra; the subjects with the lowest mtDNA levels had the lowest levels of the same cytokines. In vitro stimulation of monocytes with mtDNA concentrations similar to the highest levels observed in vivo resulted in an increased production of TNF‐α, suggesting that mtDNA can modulate the production of proinflammatory cytokines. Our findings therefore show that circulating mtDNA increases with age, and can significantly contribute to the maintenance of the low‐grade, chronic inflammation observed in elderly people.

Human models of aging and longevity

Background: The aging phenotype in humans is very heterogeneous and can be described as a complex mosaic resulting from the interaction of a variety of environmental, stochastic and genetic-epigenetic variables. Therefore, each old person must be considered as a singleton, and consequently the definition of ‘aging phenotype’ is very difficult. Objective: We discuss the phenotype of centenarians, the best example of successful aging, as well as other models exploited to study human aging and longevity, such as families enriched in long-living subjects, twins and cohorts of unrelated subjects. Methods: A critical review of literature available until March 2008. Conclusions: No single model can be considered the gold standard for the study of aging and longevity, instead the combination of results obtained from different models must be considered in order to better understand these complex phenomena. We propose that a systems biology concept such as that of ‘bow-tie’ architecture, useful for managing information flow, could help in this demanding task.

Genes, ageing and longevity in humans: problems, advantages and perspectives.

Many epidemiological data indicate the presence of a strong familial component of longevity that is largely determined by genetics, and a number of possible associations between longevity and allelic variants of genes have been described. A breakthrough strategy to get insight into the genetics of longevity is the study of centenarians, the best example of successful ageing. We review the main results regarding nuclear genes as well as the mitochondrial genome, focusing on the investigations performed on Italian centenarians, compared to those from other countries. These studies produced interesting results on many putative “longevity genes”. Nevertheless, many discrepancies are reported, likely due to the population-specific interactions between gene pools and environment. New approaches, including large-scale studies using high-throughput techniques, are urgently needed to overcome the limits of traditional association studies performed on a limited number of polymorphisms in order to make substantial progress to disentangle the genetics of a trait as complex as human longevity.

Vitamin E-gene interactions in aging and inflammatory age-related diseases: Implications for treatment. A systematic review

Aging is a complex biological phenomenon in which the deficiency of the nutritional state combined with the presence of chronic inflammation and oxidative stress contribute to the development of many age-related diseases. Under this profile, the free radicals produced by the oxidative stress lead to a damage of DNA, lipids and proteins with subsequent altered cellular homeostasis and integrity. In young-adult age, the cell has a complex efficient system to maintain a proper balance between the levels of free radicals and antioxidants ensuring the integrity of cellular components. In contrast, in old age this balance is poorly efficient compromising cellular homeostasis. Supplementation with Vitamin E can restore the balance and protect against the deteriorating effects of oxidative stress, progression of degenerative diseases, and aging. Experiments in cell cultures and in animals have clearly shown that Vitamin E has a pivotal role as antioxidant agent against the lipid peroxidation on cell membranes preserving the tissue cells from the oxidative damage. Such a role has been well documented in immune, endothelial, and brain cells from old animals describing how the Vitamin E works both at cytoplasmatic and nuclear levels with an influence on many genes related to the inflammatory/immune response. All these findings have supported a lot of clinical trials in old humans and in inflammatory age-related diseases with however contradictory and inconsistent results and even indicating a dangerous role of Vitamin E able to affect mortality. Various factors can contribute to all the discrepancies. Among them, the doses and the various isoforms of Vitamin E family (α,β,γ,δ tocopherols and the corresponding tocotrienols) used in different trials. However, the more plausible gap is the poor consideration of the Vitamin E-gene interactions that may open new roadmaps for a correct and personalized Vitamin E supplementation in aging and age-related diseases with satisfactory results in order to reach healthy aging and longevity. In this review, this peculiar nutrigenomic and/or nutrigenetic aspect is reported and discussed at the light of specific polymorphisms affecting the Vitamin E bioactivity.

Design, recruitment, logistics, and data management of the GEHA (Genetics of Healthy Ageing) project

In 2004, the integrated European project GEHA (Genetics of Healthy Ageing) was initiated with the aim of identifying genes involved in healthy ageing and longevity. The first step in the project was the recruitment of more than 2500 pairs of siblings aged 90 years or more together with one younger control person from 15 areas in 11 European countries through a coordinated and standardised effort. A biological sample, preferably a blood sample, was collected from each participant, and basic physical and cognitive measures were obtained together with information about health, life style, and family composition. From 2004 to 2008 a total of 2535 families comprising 5319 nonagenarian siblings were identified and included in the project. In addition, 2548 younger control persons aged 50-75 years were recruited. A total of 2249 complete trios with blood samples from at least two old siblings and the younger control were formed and are available for genetic analyses (e.g. linkage studies and genome-wide association studies). Mortality follow-up improves the possibility of identifying families with the most extreme longevity phenotypes. With a mean follow-up time of 3.7 years the number of families with all participating siblings aged 95 years or more has increased by a factor of 5 to 750 families compared to when interviews were conducted. Thus, the GEHA project represents a unique source in the search for genes related to healthy ageing and longevity.