Genomics of human longevity

Selenium supplementation via modulation of selenoproteins ameliorates binge drinking-induced oxidative, energetic, metabolic, and endocrine imbalance in adolescent rats' skeletal muscle

Adolescence is characterized by increased vulnerability to addiction and ethanol (EtOH) toxicity, particularly through binge drinking (BD), a favored acute EtOH-ingestion pattern among teenagers. BD, highly pro-oxidant, induces oxidative stress (OS), affecting skeletal muscle (SKM), where selenium (Se), an antioxidant element and catalytic center of selenoproteins, is stored, among other tissues. Investigating the effects of Se supplementation on SKM after BD exposure holds therapeutic promise. For this, we randomised 32 adolescent Wistar rats into 4 groups, exposed or not to intermittent i.p. BD [BD and control (C)] (3 g EtOH per kg per day), and supplemented with selenite [BDSe and CSe] (0.4 ppm). In SKM, we examined the oxidative balance, energy status (AMPK, SIRT-1), protein turnover (IRS-1, Akt1, mTOR, IGF-1, NF-κB p65, MAFbx, ULK1, pelF2α), serum myokines (myostatin, IL-6, FGF21, irisin, BDNF, IL-15, fractalkine, FSTL-1, FABP-3), and selenoproteins (GPx1, GPx4, SelM, SelP). In the pancreas, we studied the oxidative balance and SIRT-1 expression. Selenite supplementation mitigated BD-induced OS by enhancing the expression of selenoproteins, which restored oxidative balance, notably stimulating protein synthesis and normalizing the myokine profile, leading to improved SKM mass growth and metabolism, and reduced inflammation and apoptosis (caspase-3). Selenite restoration of SelP's receptor LRP1 expression, reduced by BD, outlines the crucial role of SKM in the SelP cycle, linking Se levels to SKM development. Furthermore, Se attenuated pancreatic OS, preserving insulin secretion. Se supplementation shows potential for alleviating SKM damage from BD, with additional beneficial endocrine effects on the pancreas, adipose tissue, liver, heart and brain that position it as a broad-spectrum treatment for adolescent alcohol consumption, preventing metabolic diseases in adulthood.

Childhood environment influences epigenetic age and methylation concordance of a CpG clock locus in British-Bangladeshi migrants

Migration from one location to another often comes with a change in environmental conditions. Here, we analysed features of DNA methylation in young, adult British-Bangladeshi women who experienced different environments during their childhoods: a) migrants, who grew up in Bangladesh with exposure to comparatively higher pathogen loads and poorer health care, and b) second-generation British-Bangladeshis, born to Bangladeshi parents, who grew up in the UK. We used buccal DNA to estimate DNA methylation-based age (DNAm age) from 14 migrants and 11 second-generation migrants, aged 18-35 years. 'AgeAccel,' a measure of DNAm age, independent of chronological age, showed that the group of women who spent their childhood in Bangladesh had higher AgeAccel (P = 0.028), compared to their UK peers. Since epigenetic clocks have been proposed to be associated with maintenance processes of epigenetic systems, we evaluated the preference for concordant DNA methylation at the luteinizing hormone/choriogonadotropin receptor (LHCGR/LHR) locus, which harbours one of the CpGs contributing to Horvath's epigenetic clock. Measurements on both strands of individual, double-stranded DNA molecules indicate higher stability of DNA methylation states at this LHCGR/LHR locus in samples of women who grew up in Bangladesh. Together, our two independent analytical approaches imply that childhood environments may induce subtle changes that are detectable long after exposure occurred, which might reflect altered activity of the epigenetic maintenance system or a difference in the proportion of cell types in buccal tissue. This exploratory work supports our earlier findings that adverse childhood environments lead to phenotypic life history trade-offs.

What Matters and What Matters Most for Survival After age 80? A Multidisciplinary Exploration Based on Twin Data

Given research and public interest for conditions related to an extended lifespan, we addressed the questions of what matters and what matters most for subsequent survival past age 80. The data was drawn from the population-based and multidisciplinary Swedish OCTO Twin Study, in which a sample (N = 699) consisting of identical and same-sex fraternal twin pairs, followed from age 80 until death, provided detailed data on health, physical functioning, life style, personality, and sociodemographic conditions. Information concerning date of birth and death were obtained from population census register. We estimated heritability using an ACE model and evaluated the role of multiple predictors for the mortality-related hazard rate using Cox regression. Our findings confirmed a low heritability of 12%. As expected, longer survival was associated with being a female, an apolipoprotein E (APOE) e4 allele non-carrier, and a non-smoker. Several diseases were found to be associated with shorter survival (cerebrovascular, dementia, Parkinson's, and diabetes) as well as certain health conditions (high diastolic blood pressure, low body mass index, and hip fracture). Stronger grip and better lung function, as well as better vision (but not hearing), and better cognitive function (self-evaluated and measured) was related to longer survival. Social embeddedness, better self-evaluated health, and life-satisfaction were also significantly associated with longer survival. After controlling for the impact of comorbidity, functional markers, and personality-related predictors, we found that sex, cerebrovascular diseases, compromised cognitive functioning, self-related health, and life-satisfaction remained as strong predictors. Cancer was only associated with the mortality hazard when accounting for other co-morbidities. The survival estimates were mostly in anticipated directions and contained effect sizes within the expected range. Noteworthy, we found that some of the so-called "soft-markers" remained strong predictors, despite a control for other factors. For example, self-evaluation of health and ratings of life-satisfaction provide additional and valuable information.

The plasticity of ageing and the rediscovery of ground-state prevention

In this paper, I present an emerging explanatory framework about ageing and care. In particular, I focus on how, in contrast to most classical accounts of ageing, biomedicine today construes the ageing process as a modifiable trajectory. This framing turns ageing from a stage of inexorable decline into the focus of preventive strategies, harnessing the functional plasticity of the ageing organism. I illustrate this shift by focusing on studies of the demographic dynamics in human population, observations of ageing as an intraspecifically heterogenous phenotype, and the experimental manipulation of longevity, in both model organisms and humans. I suggest that such an explanatory framework about ageing creates the epistemological conditions for the rise of a peculiar form of prevention that does not aim to address a specific condition. Rather it seeks to stall the age-related accumulation of molecular damage and functional deficits, boosting individual resilience against age-related decline. I call this preventive paradigm "ground-state prevention." While new, ground-state prevention bears conceptual resemblance to forms of medical wisdom prominent in classic Galenic medicine, as well as in the Renaissance period.

The Effect of Genetic Variants Associated With Age-Related Macular Degeneration Varies With Age

Purpose

The prevalence of age-related macular degeneration (AMD) increases dramatically with age. This large collaborative study investigates the effects of 51 late-AMD-associated genetic variants in different ages, focusing on individuals above the age of 90 years.

Methods

The study included 27,996 individuals of the International AMD Genomics Consortium; 14,539 showed late AMD (51.9%) and 13,457 were controls (48.1%). Four age groups were compiled: 60 to 69 years, n = 6514, AMD = 2210 (33.9%); 70 to 79 years, n = 12228, AMD = 6217 (51.7%); 80 to 89 years, n = 8285, AMD = 5326 (64.3%); and ≥90 years, n = 969, AMD = 686 (70.8%). The effect sizes of 51 AMD-associated genetic variants were calculated for all age groups and were compared among the age groups.

Results

Six variants were associated with late AMD in individuals ≥ 90 years of age (P ≤ 0.0006). For rs10922109 and rs570618 (both in CFH), the minor allele (MA) was protective, and minor allele frequency (MAF) increased with age in cases and controls. For rs116503776 in C2/CFB/SKIV2L, the MA was protective, and MAF increased in cases. For rs3750846 in ARMS2/HTRA1, the MA increased risk, and MAF was lower in cases with increasing age. For rs6565597 in NPLOC4/TSPAN10, the MA increased risk. For rs5754227 in SYN3/TIMP3, the MA was protective, and there was no consistent variation in MAF with age. Variants in CFH and ARMS2 showed lower effect sizes at greater age. Interaction analysis showed strong age-related effects for rs570618 (P = 2.24 × 10-7) and rs3750846 (P = 0.001). Total genetic risk was lower in individuals ≥ 90 years old (area under the curve [AUC], 0.795) than in those 70 to 79 years old (AUC, 0.831; P = 0.03).

Conclusions

Effect sizes and MAF of genetic risk factors for late AMD differed among the age groups. These results could guide future work on AMD risk assessment in older individuals.

Telomeres, Telomerase and Ageing

Telomeres are specialised structures at the end of linear chromosomes. They consist of tandem repeats of the hexanucleotide sequence TTAGGG, as well as a protein complex called shelterin. Together, they form a protective loop structure against chromosome fusion and degradation. Shortening or damage to telomeres and opening of the loop induce an uncapped state that triggers a DNA damage response resulting in senescence or apoptosis.Average telomere length, usually measured in human blood lymphocytes, was thought to be a biomarker for ageing, survival and mortality. However, it becomes obvious that regulation of telomere length is very complex and involves multiple processes. For example, the "end replication problem" during DNA replication as well as oxidative stress are responsible for the shortening of telomeres. In contrast, telomerase activity can potentially counteract telomere shortening when it is able to access and interact with telomeres. However, while highly active during development and in cancer cells, the enzyme is down-regulated in most human somatic cells with a few exceptions such as human lymphocytes. In addition, telomeres can be transcribed, and the transcription products called TERRA are involved in telomere length regulation.Thus, telomere length and their integrity are regulated at many different levels, and we only start to understand this process under conditions of increased oxidative stress, inflammation and during diseases as well as the ageing process.This chapter aims to describe our current state of knowledge on telomeres and telomerase and their regulation in order to better understand their role for the ageing process.

Understanding the Frontiers of Human Longevity in India: Imperative and Palliative Care

This article provides a theoretical and empirical insight on the study of population aging in India, with the special reference to the causes that have made it extremely significant. It evidently looks into the factors that are extensively associated with the process of population aging and have contributed to the Indian society. Demographically speaking, in the Indian context, the process of demographic transition has resulted from a falling birth rate, a slowing death rate, and spike in life expectancy. In the context of developing countries, the concept of population aging has been brought from developed countries. Initially, the outcomes of demographic transition had been experienced by developed regions followed by the rest of the world. Finally, it examines the consequences of complications that arise due to growth in life expectancy at birth, and further suggests the probable remedies to both strategy developers and policy-makers.

Genomic Approach to Understand the Association of DNA Repair with Longevity and Healthy Aging Using Genomic Databases of Oldest-Old Population

Aged population is increasing worldwide due to the aging process that is inevitable. Accordingly, longevity and healthy aging have been spotlighted to promote social contribution of aged population. Many studies in the past few decades have reported the process of aging and longevity, emphasizing the importance of maintaining genomic stability in exceptionally long-lived population. Underlying reason of longevity remains unclear due to its complexity involving multiple factors. With advances in sequencing technology and human genome-associated approaches, studies based on population-based genomic studies are increasing. In this review, we summarize recent longevity and healthy aging studies of human population focusing on DNA repair as a major factor in maintaining genome integrity. To keep pace with recent growth in genomic research, aging- and longevity-associated genomic databases are also briefly introduced. To suggest novel approaches to investigate longevity-associated genetic variants related to DNA repair using genomic databases, gene set analysis was conducted, focusing on DNA repair- and longevity-associated genes. Their biological networks were additionally analyzed to grasp major factors containing genetic variants of human longevity and healthy aging in DNA repair mechanisms. In summary, this review emphasizes DNA repair activity in human longevity and suggests approach to conduct DNA repair-associated genomic study on human healthy aging.

Nutritional Programming of Lifespan by FOXO Inhibition on Sugar-Rich Diets

Consumption of unhealthy diets is exacerbating the burden of age-related ill health in aging populations. Such diets can program mammalian physiology to cause long-term, detrimental effects. Here, we show that, in Drosophila melanogaster, an unhealthy, high-sugar diet in early adulthood programs lifespan to curtail later-life survival despite subsequent dietary improvement. Excess dietary sugar promotes insulin-like signaling, inhibits dFOXO-the Drosophila homolog of forkhead box O (FOXO) transcription factors-and represses expression of dFOXO target genes encoding epigenetic regulators. Crucially, dfoxo is required both for transcriptional changes that mark the fly's dietary history and for nutritional programming of lifespan by excess dietary sugar, and this mechanism is conserved in Caenorhabditis elegans. Our study implicates FOXO factors, the evolutionarily conserved determinants of animal longevity, in the mechanisms of nutritional programming of animal lifespan.

Phenome and genome based studies into human ageing and longevity: An overview

Human ageing is an extremely personal process leading across the life course of individuals to large population heterogeneity in the decline of functional capacity, health and lifespan. The extremes of this process are witnessed by the healthy vital 100-year-olds on one end and the 60-year-olds suffering from multiple morbid conditions on the other end of the spectrum. Molecular studies into the basis of this heterogeneity have focused on a range of endpoints and methodological approaches. The phenotype definitions most prominently investigated in these studies are either lifespan-related or biomarker based indices of the biological ageing rate of individuals and their tissues. Unlike for many complex, age-related diseases, consensus on the ultimate set of multi-biomarker ageing or lifespan-related phenotypes for genetic and genomic studies has not been reached yet. Comparable to animal models, hallmarks of age-related disease risk, healthy ageing and longevity include immune and metabolic pathways. Potentially novel genomic regions and pathways have been identified among many (epi)genomic studies into chronological age and studies into human lifespan regulation, with APOE and FOXO3A representing yet the most robust loci. Functional analysis of a handful of genes in cell-based and animal models is ongoing. The way forward in human ageing and longevity studies seems through improvements in the interpretation of the biology of the genome, in application of computational and systems biology, integration with animal models and by harmonization of repeated phenotypic and omics measures in longitudinal and intervention studies. This article is part of a Special Issue entitled: Model Systems of Aging - edited by "Houtkooper Riekelt".

Systemic Age-Associated DNA Hypermethylation of ELOVL2 Gene: In Vivo and In Vitro Evidences of a Cell Replication Process

Epigenetic remodeling is one of the major features of the aging process. We recently demonstrated that DNA methylation of ELOVL2 and FHL2 CpG islands is highly correlated with age in whole blood. Here we investigated several aspects of age-associated hypermethylation of ELOVL2 and FHL2. We showed that ELOVL2 methylation is significantly different in primary dermal fibroblast cultures from donors of different ages. Using epigenomic data from public resources, we demonstrated that most of the tissues show ELOVL2 and FHL2 hypermethylation with age. Interestingly, ELOVL2 hypermethylation was not found in tissues with very low replication rate. We demonstrated that ELOVL2 hypermethylation is associated with in vitro cell replication rather than with senescence. We confirmed intra-individual hypermethylation of ELOVL2 and FHL2 in longitudinally assessed participants from the Doetinchem Cohort Study. Finally we showed that, although the methylation of the two loci is not associated with longevity/mortality in the Leiden Longevity Study, ELOVL2 methylation is associated with cytomegalovirus status in nonagenarians, which could be informative of a higher number of replication events in a fraction of whole-blood cells. Collectively, these results indicate that ELOVL2 methylation is a marker of cell divisions occurring during human aging.

Both low circulating insulin-like growth factor-1 and high-density lipoprotein cholesterol are associated with hair loss in middle-aged women

BACKGROUND

Multiple biomarkers have been associated with hair loss in women, but studies have shown inconsistent results.

OBJECTIVES

We investigated the associations between markers of cardiovascular disease risk (e.g. serum lipid levels and hypertension) and ageing [e.g. 25-hydroxyvitamin D and insulin-like growth factor (IGF)] with hair loss in a population of middle-aged women.

METHODS

In a random subgroup of 323 middle-aged women (mean age 61·5 years) from the Leiden Longevity Study, hair loss was graded by three assessors using the Sinclair scale; women with a mean score > 1·5 were classified as cases with hair loss.

RESULTS

Every 1 SD increase in high-density lipoprotein (HDL) cholesterol was associated with a 0·65-times lower risk [95% confidence interval (CI) 0·46-0·91] of hair loss. For IGF-1 the risk was 0·68 times lower (95% CI 0·48-0·97) per 1 SD increase, independently of the other studied variables. Women with both IGF-1 and HDL cholesterol levels below the medians of the study population had a 3·47-times higher risk (95% CI 1·30-9·25) of having hair loss.

CONCLUSIONS

Low HDL cholesterol and IGF-1 were associated with a higher risk of hair loss in women. However, further studies are required to infer causal relationships.

Systems-level analysis of human aging genes shed new light on mechanisms of aging

Although studies over the last decades have firmly connected a number of genes and molecular pathways to aging, the aging process as a whole still remains poorly understood. To gain novel insights into the mechanisms underlying aging, instead of considering aging genes individually, we studied their characteristics at the systems level in the context of biological networks. We calculated a comprehensive set of network characteristics for human aging-related genes from the GenAge database. By comparing them with other functional groups of genes, we identified a robust group of aging-specific network characteristics. To find the structural basis and the molecular mechanisms underlying this aging-related network specificity, we also analyzed protein domain interactions and gene expression patterns across different tissues. Our study revealed that aging genes not only tend to be network hubs, playing important roles in communication among different functional modules or pathways, but also are more likely to physically interact and be co-expressed with essential genes. The high expression of aging genes across a large number of tissue types also points to a high level of connectivity among aging genes. Unexpectedly, contrary to the depletion of interactions among hub genes in biological networks, we observed close interactions among aging hubs, which renders the aging subnetworks vulnerable to random attacks and thus may contribute to the aging process. Comparison across species reveals the evolution process of the aging subnetwork. As the organisms become more complex, the complexity of its aging mechanisms increases and their aging hub genes are more functionally connected.

The Emergence of Geroscience as an Interdisciplinary Approach to the Enhancement of Health Span and Life Span

Research on the biology of aging has accelerated rapidly in the last two decades. It is now at the point where translation of the findings into useful approaches to improve the health of the elderly population seems possible. In trying to fill that gap, a new field termed geroscience will be articulated here that attempts to identify the biological underpinnings for the age-dependency of most chronic diseases. Herein, I will review the major conceptual issues leading to the formulation of geroscience as a field, as well as give examples of current areas of inquiry in which basic aging biology research could lead to therapeutic approaches to address age-related chronic diseases, not one at a time, but most of them in unison.

IL7R gene expression network associates with human healthy ageing

Background

The level of expression of the interleukin 7 receptor (IL7R) gene in blood has recently been found to be associated with familial longevity and healthy ageing. IL7R is crucial for T cell development and important for immune competence. To further investigate the IL7R pathway in ageing, we identified the closest interacting genes to construct an IL7R gene network that consisted of IL7R and six interacting genes: IL2RG, IL7, TSLP, CRLF2, JAK1 and JAK3. This network was explored for association with chronological age, familial longevity and immune-related diseases (type 2 diabetes, chronic obstructive pulmonary disease and rheumatoid arthritis) in 87 nonagenarians, 337 of their middle-aged offspring and 321 middle-aged controls from the Leiden Longevity Study (LLS).

Results

We observed that expression levels within the IL7R gene network were significantly different between the nonagenarians and middle-aged controls (P = 4.6 × 10⁻⁴), being driven by significantly lower levels of expression in the elderly of IL7, IL2RG and IL7R. After adjustment for multiple testing and white blood cell composition and in comparison with similarly aged controls, middle-aged offspring of nonagenarian siblings exhibit a lower expression level of IL7R only (P = 0.006). Higher IL7R gene expression in the combined group of middle-aged offspring and controls is associated with a higher prevalence of immune-related disease (P = 0.001). On the one hand, our results indicate that lower IL7R expression levels, as exhibited by the members of long-lived families that can be considered as ‘healthy agers’, are beneficial in middle age. This is augmented by the observation that higher IL7R gene expression associates with immune-related disease. On the other hand, IL7R gene expression in blood is lower in older individuals, indicating that low IL7R gene expression might associate with reduced health. Interestingly, this contradictory result is supported by the observation that a higher IL7R gene expression level is associated with better prospective survival, both in the nonagenarians (Hazard ratio (HR) = 0.63, P = 0.037) and the middle-aged individuals (HR = 0.33, P = 1.9 × 10^–4).

Conclusions

Overall, we conclude that the IL7R network reflected by gene expression levels in blood may be involved in the rate of ageing and health status of elderly individuals.

Electronic supplementary material

The online version of this article (doi:10.1186/s12979-015-0048-6) contains supplementary material, which is available to authorized users.

Associations between STR autosomal markers and longevity

Life span is a complex and multifactorial trait, which is shaped by genetic, epigenetic, environmental, and stochastic factors. The possibility that highly hypervariable short tandem repeats (STRs) associated with longevity has been largely explored by comparing the genotypic pools of long lived and younger individuals, but results so far have been contradictory. In view of these contradictory findings, the present study aims to investigate whether HUMTHO1 and HUMCSF1PO STRs, previously associated with longevity, exert a role as a modulator of life expectancy, as well as to assess the extent to which other autosomal STR markers are associated with human longevity in population from northern Spain. To that end, 21 autosomal microsatellite markers have been studied in 304 nonagenarian individuals (more than 90 years old) and 516 younger controls of European descent. Our results do not confirm the association found in previous studies between longevity and THO1 and CSF1PO loci. However, significant association between longevity and autosomal STR markers D12S391, D22S1045, and DS441 was observed. Even more, when we compared allelic frequency distribution of the 21 STR markers between cases and controls, we found that 6 out of the 21 STRs studied showed different allelic frequencies, thus suggesting that the genomic portrait of the human longevity is far complex and probably shaped by a high number of genomic loci.

Longevity and skeletal muscle mass: the role of IGF signalling, the sirtuins, dietary restriction and protein intake

Advancing age is associated with a progressive loss of skeletal muscle (SkM) mass and function. Given the worldwide aging demographics, this is a major contributor to morbidity, escalating socio-economic costs and ultimately mortality. Previously, it has been established that a decrease in regenerative capacity in addition to SkM loss with age coincides with suppression of insulin/insulin-like growth factor signalling pathways. However, genetic or pharmacological modulations of these highly conserved pathways have been observed to significantly enhance life and healthspan in various species, including mammals. This therefore provides a controversial paradigm in which reduced regenerative capacity of skeletal muscle tissue with age potentially promotes longevity of the organism. This paradox will be assessed and considered in the light of the following: (i) the genetic knockout, overexpression and pharmacological models that induce lifespan extension (e.g. IRS-1/s6K KO, mTOR inhibition) versus the important role of these signalling pathways in SkM growth and adaptation; (ii) the role of the sirtuins (SIRTs) in longevity versus their emerging role in SkM regeneration and survival under catabolic stress; (iii) the role of dietary restriction and its impact on longevity versus skeletal muscle mass regulation; (iv) the crosstalk between cellular energy metabolism (AMPK/TSC2/SIRT1) and survival (FOXO) versus growth and repair of SkM (e.g. AMPK vs. mTOR); and (v) the impact of protein feeding in combination with dietary restriction will be discussed as a potential intervention to maintain SkM mass while increasing longevity and enabling healthy aging.

Genetics and pharmacology of longevity: the road to therapeutics for healthy aging

Aging can be defined as the progressive decline in tissue and organismal function and the ability to respond to stress that occurs in association with homeostatic failure and the accumulation of molecular damage. Aging is the biggest risk factor for human disease and results in a wide range of aging pathologies. Although we do not completely understand the underlying molecular basis that drives the aging process, we have gained exceptional insights into the plasticity of life span and healthspan from the use of model organisms such as the worm Caenorhabditis elegans and the fruit fly Drosophila melanogaster. Single-gene mutations in key cellular pathways that regulate environmental sensing, and the response to stress, have been identified that prolong life span across evolution from yeast to mammals. These genetic manipulations also correlate with a delay in the onset of tissue and organismal dysfunction. While the molecular genetics of aging will remain a prosperous and attractive area of research in biogerontology, we are moving towards an era defined by the search for therapeutic drugs that promote healthy aging. Translational biogerontology will require incorporation of both therapeutic and pharmacological concepts. The use of model organisms will remain central to the quest for drug discovery, but as we uncover molecular processes regulated by repurposed drugs and polypharmacy, studies of pharmacodynamics and pharmacokinetics, drug-drug interactions, drug toxicity, and therapeutic index will slowly become more prevalent in aging research. As we move from genetics to pharmacology and therapeutics, studies will not only require demonstration of life span extension and an underlying molecular mechanism, but also the translational relevance for human health and disease prevention.

Association between SERPING1 rs2511989 polymorphism and age-related macular degeneration: Meta-analysis

AIM

To investigate the association between SERPING1 rs2511989 (G>A) polymorphism and age-related macular degeneration (AMD).

METHODS

A number of electronic databases (up to July 15, 2014) were searched independently by two investigators. A Meta-analysis was performed on the association between SERPING1 rs2511989 polymorphism and AMD. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated.

RESULTS

Eight studies with 16 cohorts consisting of 9163 cases and 6813 controls were included in this Meta-analysis. There was no significant association between rs2511989 polymorphism and AMD under all genetic models in overall estimates (A vs G: OR= 0.938, 95%CI =0.858-1.025; AA vs GG:OR =0.871, 95%CI =0.719-1.056; AG vs GG: OR =0.944, 95%CI =0.845-1.054; AA+AG vs GG: OR =0.927, 95% CI =0.823-1.044; AA vs AG+GG: OR =0.890, 95%CI =0.780-1.034). Cumulative Meta-analyses also showed a trend of no association between rs2511989 polymorphism and AMD as information accumulated by year. Subgroup analysis and Meta-regression analysis indicated that age-matching status was the main source of heterogeneity. Sensitivity analysis found the results in overall comparisons and subgroup comparisons of white subjects under the allele model were found to have significantly statistical differences after studies deviating from Hardy-Weinberg equilibrium (HWE) were excluded (overall: OR=0.918, 95%CI = 0.844-0.999, P =0.049; whites: OR =0.901, 95%CI = 0.817-0.994, P =0.038). However, the results were not sufficiently robust for further sensitivity analysis and statistical differences disappeared on applying Bonferroni correction (with a significance level set at 0.05/25).

CONCLUSION

This Meta-analysis indicates that SERPING1 rs2511989 polymorphism and AMD tend to have no association with each other. Age matching status is a big confounding factor, and more studies with subtle designs are warranted in future.

Aging and cardiovascular diseases: the role of gene-diet interactions

In the study of longevity, increasing importance is being placed on the concept of healthy aging rather than considering the total number of years lived. Although the concept of healthy lifespan needs to be defined better, we know that cardiovascular diseases (CVDs) are the main age-related diseases. Thus, controlling risk factors will contribute to reducing their incidence, leading to healthy lifespan. CVDs are complex diseases influenced by numerous genetic and environmental factors. Numerous gene variants that are associated with a greater or lesser risk of the different types of CVD and of intermediate phenotypes (i.e., hypercholesterolemia, hypertension, diabetes) have been successfully identified. However, despite the close link between aging and CVD, studies analyzing the genes related to human longevity have not obtained consistent results and there has been little coincidence in the genes identified in both fields. The APOE gene stands out as an exception, given that it has been identified as being relevant in CVD and longevity. This review analyzes the genomic and epigenomic factors that may contribute to this, ranging from identifying longevity genes in model organisms to the importance of gene-diet interactions (outstanding among which is the case of the TCF7L2 gene).

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.

Association analyses of insulin signaling pathway gene polymorphisms with healthy aging and longevity in Americans of Japanese ancestry

Evidence from model organisms suggests that the insulin/IGF-1 signaling pathway has an important, evolutionarily conserved influence over rate of aging and thus longevity. In humans, the FOXO3 gene is the only widely replicated insulin/IGF-1 signaling pathway gene associated with longevity across multiple populations. Therefore, we conducted a nested case-control study of other insulin/IGF-1 signaling genes and longevity, utilizing a large, homogeneous, long-lived population of American men of Japanese ancestry, well characterized for aging phenotypes. Genotyping was performed of single nucleotide polymorphisms, tagging most of the genetic variation across several genes in the insulin/IGF-1 signaling pathway or related gene networks that may be influenced by FOXO3, namely, ATF4, CBL, CDKN2, EXO1, and JUN. Two initial, marginal associations with longevity did not remain significant after correction for multiple comparisons, nor were they correlated with aging-related phenotypes.

Nutrition and health during mid-life: searching for solutions and meeting challenges for the aging population

Interactions between genetic (genome) and environmental factors (epigenome) operate during a person's entire lifespan. The aging process is associated with several cellular and organic functional alterations that, at the end, cause multi-organic cell failure. Epigenetic mechanisms of aging are modifiable by appropriate preventive actions mediated by sirtuins, caloric input, diet components, adipose tissue-related inflammatory reactions, and physical activity. The Mediterranean lifestyle has been for many millennia a daily habit for people in Western civilizations living around the Mediterranean sea who worked intensively and survived with very few seasonal foods. A high adherence to the traditional Mediterranean diet is associated with low mortality (higher longevity) and reduced risk of developing chronic diseases, including cancer, the metabolic syndrome, depression and cardiovascular and neurodegenerative diseases. Reports indicate that some dietary components, such as olive oil, antioxidants, omega-3 and -6 polyunsaturated acids, polyphenols and flavonoids, mediate beneficial anti-aging effects (anti-chronic diseases and increased longevity). Equally, physical activity displays a positive effect, producing caloric consumption and regulation of adipose and pancreatic function. The predictive strength of some food patterns may be a way of developing recommendations for food and health policies. This paper will discuss several ways of improving health during mid-life, focusing on certain groups of functional foods and healthy habits which may reduce or prevent age-related chronic diseases.

Leukocyte telomere length associates with prospective mortality independent of immune-related parameters and known genetic markers

Background: Human leukocyte telomere length (LTL) decreases with age and shorter LTL has previously been associated with increased prospective mortality. However, it is not clear whether LTL merely marks the health status of an individual by its association with parameters of immune function, for example, or whether telomere shortening also contributes causally to lifespan variation in humans.

Methods: We measured LTL in 870 nonagenarian siblings (mean age 93 years), 1580 of their offspring and 725 spouses thereof (mean age 59 years) from the Leiden Longevity Study (LLS).

Results: We found that shorter LTL is associated with increased prospective mortality in middle (30–80 years; hazard ratio (HR) = 0.75, P = 0.001) and highly advanced age (≥90 years; HR = 0.92, P = 0.028), and show that this association cannot be explained by the association of LTL with the immune-related markers insulin-like growth factor 1 to insulin-like growth factor binding protein 3 molar ratio, C-reactive protein, interleukin 6, cytomegalovirus serostatus or white blood cell counts. We found no difference in LTL between the middle-aged LLS offspring and their spouses (β = 0.006, P = 0.932). Neither did we observe an association of LTL-associated genetic variants with mortality in a prospective meta-analysis of multiple cohorts (n = 8165).

Conclusions: We confirm LTL to be a marker of prospective mortality in middle and highly advanced age and additionally show that this association could not be explained by the association of LTL with various immune-related markers. Furthermore, the approaches performed here do not further support the hypothesis that LTL variation contributes to the genetic propensity for longevity.

Pioglitazone does not improve insulin signaling in mice with GH over-expression

Type 2 diabetes and obesity are very serious health problems in both developed and developing countries. An increased level of GH is known to promote insulin resistance. Transgenic (Tg) mice over-expressing bovine GH are short-living and characterized, among other traits, by hyperinsulinemia and increased insulin resistance in comparison with normal (N) mice. Pioglitazone (PIO) is a member of the thiazolidinediones - a group of insulin-sensitizing drugs that are selective agonists of peroxisome proliferator-activated receptor gamma (PPARγ). The aim of the study was to analyze the effects of PIO on the insulin-signaling pathway in Tg and N mice. Plasma levels of insulin and glucose as well as hepatic levels of proteins involved in insulin signaling were analyzed by ELISA or western blot methods. Treatment with PIO decreased plasma level of glucose in N mice only. Similarly, PIO increased insulin sensitivity (expressed as the relative insulin sensitivity index; RISI) only in N mice. In the liver, PIO decreased the phosphorylation of insulin receptor substrate-1 (IRS1) at a serine residue (Ser(307)-pS-IRS1), which inhibits insulin action, and had a tendency to increase tyrosine phosphorylation of IRS2 (Tyr-pY-IRS2) only in N mice but did not affect either of these parameters in Tg mice. Levels of total and phosphorylated mammalian target of rapamycin were increased in Tg mice. Moreover, the level of AKT2 was decreased by PIO in N mice only. In conclusion, the lack of improvement of insulin sensitivity in insulin-resistant Tg mice during PIO treatment indicates that chronically elevated GH levels can inhibit the beneficial effects of PIO on insulin signaling.

Functional diversity and pharmacological profiles of the FKBPs and their complexes with small natural ligands

From 5 to 12 FK506-binding proteins (FKBPs) are encoded in the genomes of disparate marine organisms, which appeared at the dawn of evolutionary events giving rise to primordial multicellular organisms with elaborated internal body plan. Fifteen FKBPs, several FKBP-like proteins and some splicing variants of them are expressed in humans. Human FKBP12 and some of its paralogues bind to different macrocyclic antibiotics such as FK506 or rapamycin and their derivatives. FKBP12/(macrocyclic antibiotic) complexes induce diverse pharmacological activities such as immunosuppression in humans, anticancerous actions and as sustainers of quiescence in certain organisms. Since the FKBPs bind to various assemblies of proteins and other intracellular components, their complexes with the immunosuppressive drugs may differentially perturb miscellaneous cellular functions. Sequence-structure relationships and pharmacological profiles of diverse FKBPs and their involvement in crucial intracellular signalization pathways and modulation of cryptic intercellular communication networks were discussed.

Lipidomics in longevity and healthy aging

The role of classical lipids in aging diseases and human longevity has been widely acknowledged. Triglyceride and cholesterol concentrations are clinically assessed to infer the risk of cardiovascular disease while larger lipoprotein particle size and low triglyceride levels have been identified as markers of human longevity. The rise of lipidomics as a branch of metabolomics has provided an additional layer of accuracy to pinpoint specific lipids and its association with aging diseases and longevity. The molecular composition and concentration of lipid species determine their cellular localization, metabolism, and consequently, their impact in disease and health. For example, low density lipoproteins are the main carriers of sphingomyelins and ceramides, while high density lipoproteins are mostly loaded with ether phosphocholines, partly explaining their opposing roles in atherogenesis. Moreover, the identification of specific lipid species in aging diseases and longevity would aid to clarify how these lipids alter health and influence longevity. For instance, ether phosphocholines PC (O-34:1) and PC (O-34:3) have been positively associated with longevity and negatively with diabetes, and hypertension, but other species of phosphocholines show no effect or an opposite association with these traits confirming the relevance of the identification of molecular lipid species to tackle our understanding of healthy aging and disease. Up-to-date, a minor fraction of the human plasma lipidome has been associated to healthy aging and longevity, further research would pinpoint toward specific lipidomic profiles as potential markers of healthy aging and metabolic diseases.

Bile acid look-alike controls life span in C. elegans

Extensive transcriptional networks maintain sterol homeostasis across species, underscoring the importance of sterol balance for healthy life. Magner et al. (2013) now show that, in C. elegans, the nuclear receptor NHR-8 is key in regulation of cholesterol balance and production of dafachronic acid, a bile acid-like steroid that controls longevity.

Thyroid hormone signaling and homeostasis during aging

Studies in humans and in animal models show negative correlations between thyroid hormone (TH) levels and longevity. TH signaling is implicated in maintaining and integrating metabolic homeostasis at multiple levels, notably centrally in the hypothalamus but also in peripheral tissues. The question is thus raised of how TH signaling is modulated during aging in different tissues. Classically, TH actions on mitochondria and heat production are obvious candidates to link negative effects of TH to aging. Mitochondrial effects of excess TH include reactive oxygen species and DNA damage, 2 factors often considered as aging accelerators. Inversely, caloric restriction, which can retard aging from nematodes to primates, causes a rapid reduction of circulating TH, reducing metabolism in birds and mammals. However, many other factors could link TH to aging, and it is these potentially subtler and less explored areas that are highlighted here. For example, effects of TH on membrane composition, inflammatory responses, stem cell renewal and synchronization of physiological responses to light could each contribute to TH regulation of maintenance of homeostasis during aging. We propose the hypothesis that constraints on TH signaling at certain life stages, notably during maturity, are advantageous for optimal aging.

MAP3K7 and GSTZ1 are associated with human longevity: a two-stage case-control study using a multilocus genotyping

The pathways that regulate energy homeostasis, the mechanisms of damage repair, and the signaling response to internal environmental changes or external signals have been shown to be critical in modulating lifespan of model organisms and humans. In order to investigate whether genetic variation of genes involved in these pathways contribute to longevity, a two-stage case-control study in two independent sets of long-lived individuals from Calabria (Italy) was performed. In stage 1, 317 SNPs in 104 genes were analyzed in 78 cases (median age 98 years) and 71 controls (median age 67 years). In stage 2, 31 candidate SNPs identified in stage 1 (π markers = 0.1) were analyzed in an independent sample composed by 288 cases (median age 92 years) and 554 controls (median age 67 years). Two SNPs, rs282070 located in intron 1 of the MAP3K7 gene, and rs2111699 located in intron 1 of the GSTZ1 gene, were significantly associated (after adjustment for multiple testing) with longevity in stage 2 (p = 1.1 × 10(-3) and p = 1.4 × 10(-3), respectively). Interestingly, both genes are implicated in the cellular response to internal and external environmental changes, playing a crucial role in the inflammation processes that accompany aging. Our data confirm that long-lived subjects are endowed with genetic variants that allow them to optimize these cellular responses and to better deal with environmental and internal stresses.

Genome-wide linkage analysis for human longevity: Genetics of Healthy Aging Study

Clear evidence exists for heritability of human longevity, and much interest is focused on identifying genes associated with longer lives. To identify such longevity alleles, we performed the largest genome-wide linkage scan thus far reported. Linkage analyses included 2118 nonagenarian Caucasian sibling pairs that have been enrolled in 15 study centers of 11 European countries as part of the Genetics of Healthy Aging (GEHA) project. In the joint linkage analyses, we observed four regions that show linkage with longevity; chromosome 14q11.2 (LOD = 3.47), chromosome 17q12-q22 (LOD = 2.95), chromosome 19p13.3-p13.11 (LOD = 3.76), and chromosome 19q13.11-q13.32 (LOD = 3.57). To fine map these regions linked to longevity, we performed association analysis using GWAS data in a subgroup of 1228 unrelated nonagenarian and 1907 geographically matched controls. Using a fixed-effect meta-analysis approach, rs4420638 at the TOMM40/APOE/APOC1 gene locus showed significant association with longevity (P-value = 9.6 × 10(-8) ). By combined modeling of linkage and association, we showed that association of longevity with APOEε4 and APOEε2 alleles explain the linkage at 19q13.11-q13.32 with P-value = 0.02 and P-value = 1.0 × 10(-5) , respectively. In the largest linkage scan thus far performed for human familial longevity, we confirm that the APOE locus is a longevity gene and that additional longevity loci may be identified at 14q11.2, 17q12-q22, and 19p13.3-p13.11. As the latter linkage results are not explained by common variants, we suggest that rare variants play an important role in human familial longevity.

Genomics of human health and aging

Despite notable progress of the candidate-gene and genome-wide association studies (GWAS), understanding the role of genes contributing to human health and lifespan is still very limited. We use the Framingham Heart Study to elucidate if recognizing the role of evolution and systemic processes in an aging organism could advance such studies. We combine throughput methods of GWAS with more detail methods typical for candidate-gene analyses and show that both lifespan and ages at onset of CVD and cancer can be controlled by the same allelic variants. The risk allele carriers are at highly significant risk of premature death (e.g., RR=2.9, p=5.0 × 10(-66)), onset of CVD (e.g., RR=1.6, p=4.6 × 10(-17)), and onset of cancer (e.g., RR=1.6, p=1.5 × 10(-6)). The mechanism mediating the revealed genetic associations is likely associated with biological aging. These aging-related phenotypes are associated with a complex network which includes, in this study, 62 correlated SNPs even so these SNPs can be on non-homologous chromosomes. A striking result is three-fold, highly significant (p=3.6 × 10(-10)) enrichment of non-synonymous SNPs (N=27) in this network compared to the entire qualified set of the studied SNPs. Functional significance of this network is strengthened by involvement of genes for these SNPs in fundamental biological processes related to aging (e.g., response to stimuli, protein degradation, apoptosis) and by connections of these genes with neurological (20 genes) and cardio-vascular (nine genes) processes and tumorigenesis (10 genes). These results document challenging role of gene networks in regulating human health and aging and call for broadening focus on genomics of such phenotypes.

Ageing as a risk factor for disease

Age is the main risk factor for the prevalent diseases of developed countries: cancer, cardiovascular disease and neurodegeneration. The ageing process is deleterious for fitness, but can nonetheless evolve as a consequence of the declining force of natural selection at later ages, attributable to extrinsic hazards to survival: ageing can then occur as a side-effect of accumulation of mutations that lower fitness at later ages, or of natural selection in favour of mutations that increase fitness of the young but at the cost of a higher subsequent rate of ageing. Once thought of as an inexorable, complex and lineage-specific process of accumulation of damage, ageing has turned out to be influenced by mechanisms that show strong evolutionary conservation. Lowered activity of the nutrient-sensing insulin/insulin-like growth factor/Target of Rapamycin signalling network can extend healthy lifespan in yeast, multicellular invertebrates, mice and, possibly, humans. Mitochondrial activity can also promote ageing, while genome maintenance and autophagy can protect against it. We discuss the relationship between evolutionarily conserved mechanisms of ageing and disease, and the associated scientific challenges and opportunities.

Identifying the genomic determinants of aging and longevity in human population studies: progress and challenges

Human lifespan variation is mainly determined by environmental factors, whereas the genetic contribution is 25–30% and expected to be polygenic. Two complementary fields go hand in hand in order to unravel the mechanisms of biological aging: genomic and biomarker research. Explorative and candidate gene studies of the human genome by genetic, transcriptomic, and epigenomic approaches have resulted in the identification of a limited number of interesting positive linkage regions, genes, and pathways that contribute to lifespan variation. The possibilities to further exploit these findings are rapidly increasing through the use of novel technologies, such as next-generation sequencing. Genomic research is progressively being integrated with biomarker studies on aging, including the application of (noninvasive) deep phenotyping and omics data – generated using novel technologies – in a wealth of studies in human populations. Hence, these studies may assist in obtaining a more holistic perspective on the role of the genome in aging and lifespan regulation.

The frequency of 4 common gene polymorphisms in nonagenarians, centenarians, and average life span individuals

Single nucleotide polymorphisms of angiotensin-converting enzyme (ACE) such as rs1799752, nuclear factor kappa B (NFkB) such as rs28362491 and cholesteryl ester transport protein (CETP) such as rs708272 (TaqB1) and rs5882 (I405V) were evaluated in nonagenarians, centenarians, and average life span individuals (controls). The study population (n = 307; 190 nonagenarians, 12 centenarians and 105 middle-aged controls) was genotyped for ACE, NFkB, and CETP genetic variants. The age of nonagenarian and centenarian group ranged between 90 and 111 years; centenarians and controls age ranged from 99 to 111, and from 18 to 80 years, respectively. The I carriers of ACE I/D gene were fewer in nonagenarians compared to centenarians (37.6% vs 62.5%, P = .016). The I carriers of ACE gene were more frequent in centenarians compared to controls (62% vs 41%, P = .045). No differences in frequency of common NFkB and CETP genotypes between patients with exceptional longevity and middle-aged patients were observed.

Chronic kidney disease: a clinical model of premature aging

Premature aging is a process associated with a progressive accumulation of deleterious changes over time, an impairment of physiologic functions, and an increase in the risk of disease and death. Regardless of genetic background, aging can be accelerated by the lifestyle choices and environmental conditions to which our genes are exposed. Chronic kidney disease is a common condition that promotes cellular senescence and premature aging through toxic alterations in the internal milieu. This occurs through several mechanisms, including DNA and mitochondria damage, increased reactive oxygen species generation, persistent inflammation, stem cell exhaustion, phosphate toxicity, decreased klotho expression, and telomere attrition. Because recent evidence suggests that both increased local signaling of growth factors (through the nutrient-sensing mammalian target of rapamycin) and decreased klotho expression are important modulators of aging, interventions that target these should be tested in this prematurely aged population.

Nutrition and ageing: knowledge, gaps and research priorities

Over the past two centuries human life expectancy has increased by nearly 50 years. Genetic factors account for about one-third of the variation in life expectancy so that most of the inter-individual variation in lifespan is explained by stochastic and environmental factors, including diet. In some model organisms, dietary (energy) restriction is a potent, and highly reproducible, means of increasing lifespan and of reducing the risk of age-related dysfunction although whether this strategy is effective in human subjects is unknown. This is ample evidence that the ageing process is plastic and research demonstrates that ageing is driven by the accumulation of molecular damage, which causes the changes in cell and tissue function that characterise the ageing phenotype. This cellular, tissue and organ damage results in the development of age-related frailty, disabilities and diseases. There are compelling observational data showing links between eating patterns, e.g. the Mediterranean dietary pattern, and ageing. In contrast, there is little empirical evidence that dietary changes can prolong healthy lifespan and there is even less information about the intervention modalities that can produce such sustainable dietary behaviour changes. In conclusion, current research needs include (1) a better understanding of the causal biological pathways linking diet with the ageing trajectory, (2) the development of lifestyle-based interventions, including dietary changes, which are effective in preventing age-related disease and disability and (3) the development of robust markers of healthy ageing, which can be used as surrogate outcome measures in the development and testing of dietary interventions designed to enhance health and well-being long into old age.

Nucleic acid delivery: roles in biogerontological interventions

Prolongation of longevity is a history-long desire of humans. Driven by the genetic contribution to longevity and the remarkable plasticity of healthy lifespan as demonstrated in animal models, arduous efforts have been directed to aging and longevity research over the years. Today, our understanding of lifespan determination is much greater than it was in the past, but administrable interventions for longevity enhancement are still virtually absent. The aim of this article is to highlight the technical gap between basic biogerontological research and intervention development, and to explore the importance of nucleic acid (NA) delivery technologies in bridging the gap. It is hoped that this article can engender more awareness of the roles of NA delivery technologies in biogerontological interventions, particularly NA therapy.

Epigenetics and aging

Over the past two decades, a growing interest on the research of the biological basis of human longevity has emerged, in order to clarify the intricacy of biological and environmental factors affecting (together with stochastic factors) the quality and the rate of human aging. These researches have outlined a complex scenario in which epigenetic marks, such as DNA methylation and numerous histone modifications, are emerging as important factors of the overall variation in life expectancy. In fact, epigenetic marks, that are responsible of the establishment of specific expression programs and of genome stability, represent a "drawbridge" across genetic, environmental and stochastic factors. In this review we provide an overview on the current knowledge and the general features of the epigenetic modifications characterizing the aging process.

Genetics of longevity in model organisms: debates and paradigm shifts

Discovering the biological basis of aging is one of the greatest remaining challenges for science. Work on the biology of aging has discovered a range of interventions and pathways that control aging rate. A picture is emerging of a signaling network that is sensitive to nutritional status and that controls growth, stress resistance, and aging. This network includes the insulin/IGF-1 and target of rapamycin (TOR) pathways and likely mediates the effects of dietary restriction on aging. Yet the biological processes upon which these pathways act to control life span remain unclear. A long-standing guiding assumption about aging is that it is caused by wear and tear, particularly damage at the molecular level. One view is that reactive oxygen species (ROS), including free radicals, generated as by-products of cellular metabolism, are a major contributor to this damage. Yet many recent tests of the oxidative damage theory have come up negative. Such tests have opened an exciting new phase in biogerontology in which fundamental assumptions about aging are being reexamined and revolutionary concepts are emerging. Among these concepts is the hyperfunction theory, which postulates that processes contributing to growth and reproduction run on in later life, leading to hypertrophic and hyperplastic pathologies. Here we reexamine central concepts about the nature of aging.

Bitter taste receptor polymorphisms and human aging

Several studies have shown that genetic factors account for 25% of the variation in human life span. On the basis of published molecular, genetic and epidemiological data, we hypothesized that genetic polymorphisms of taste receptors, which modulate food preferences but are also expressed in a number of organs and regulate food absorption processing and metabolism, could modulate the aging process. Using a tagging approach, we investigated the possible associations between longevity and the common genetic variation at the three bitter taste receptor gene clusters on chromosomes 5, 7 and 12 in a population of 941 individuals ranging in age from 20 to 106 years from the South of Italy. We found that one polymorphism, rs978739, situated 212 bp upstream of the TAS2R16 gene, shows a statistically significant association (p = 0.001) with longevity. In particular, the frequency of A/A homozygotes increases gradually from 35% in subjects aged 20 to 70 up to 55% in centenarians. These data provide suggestive evidence on the possible correlation between human longevity and taste genetics.

Pleiotropy of segregating genetic variants that affect honey bee worker life expectancy

In contrast to many other complex traits, the natural genetic architecture of life expectancy has not been intensely studied, particularly in non-model organisms, such as the honey bee (Apis mellifera L.). Multiple factors that determine honey bee worker lifespan have been identified and genetic analyses have been performed on some of those traits. Several of the traits are included in a suite of correlated traits that form the pollen hoarding syndrome, which was named after the behavior to store surplus pollen in the nest and is tied to social evolution. Here, seven quantitative trait loci that had previously been identified for their effects on different aspects of the pollen hoarding syndrome were studied for their genetic influence on the survival of adult honey bee workers. To gain a more comprehensive understanding of the genetic architecture of worker longevity, a panel of 280 additional SNP markers distributed across the genome was also tested. Allelic distributions were compared between young and old bees in two backcross populations of the bi-directionally selected high- and low-pollen hoarding strain. Our results suggest a pleiotropic effect of at least one of the behavioral quantitative trait loci on worker longevity and one significant and several other putative genetic effects in other genomic regions. At least one locus showed evidence for strong antagonistic pleiotropy and several others suggested genetic factors that influence pre-emergence survival of worker honey bees. Thus, the predicted association between worker lifespan and the pollen hoarding syndrome was supported at the genetic level and the magnitude of the identified effects also strengthened the view that naturally segregating genetic variation can have major effects on age-specific survival probability in the wild.

Transcriptome analysis of a long-lived natural Drosophila variant: a prominent role of stress- and reproduction-genes in lifespan extension

Background

While studying long-lived mutants has advanced our understanding of the processes involved in ageing, the mechanisms underlying natural variation in lifespan and ageing rate remain largely unknown. Here, we characterise genome-wide expression patterns of a long-lived, natural variant of Drosophila melanogaster resulting from selection for starvation resistance (SR) and compare it with normal-lived control flies (C). We do this at two time points representing middle age (90% survival) and old age (10% survival) respectively, in three adult diets (malnutrition, optimal food, and overfeeding).

Results

We found profound differences between Drosophila lines in their age-related expression. Most of the age-associated changes in normal-lived flies were abrogated in long-lived Drosophila. The stress-related genes, including those involved in proteolysis and cytochrome P450, were generally higher expressed in SR flies and showed a smaller increase in expression with age compared to C flies. The genes involved in reproduction showed a lower expression in middle-aged SR than in C flies and, unlike C flies, a lack of their downregulation with age. Further, we found that malnutrition strongly affected age-associated transcript patterns overriding the differences between the lines. However, under less stressful dietary conditions, line and diet affected age-dependent expression similarly. Finally, we present lists of candidate markers of ageing and lifespan extension.

Conclusions

Our study unveils transcriptional changes associated with lifespan extension in SR Drosophila. The results suggest that natural genetic variation for SR and lifespan can operate through similar transcriptional mechanisms as those of dietary restriction and life-extending mutations.

Epidemiological, genetic and epigenetic aspects of the research on healthy ageing and longevity

Healthy ageing and longevity in humans result from a number of factors, including genetic background, favorable environmental and social factors and chance.

In this article we aimed to overview the research on the biological basis of human healthy ageing and longevity, discussing the role of epidemiological, genetic and epigenetic factors in the variation of quality of ageing and lifespan, including the most promising candidate genes investigated so far. Moreover, we reported the methodologies applied for their identification, discussing advantages and disadvantages of the different approaches and possible solutions that can be taken to overcome them. Finally, we illustrated the recent approaches to define healthy ageing and underlined the role that the emerging field of epigenetics is gaining in the search for the determinants of healthy ageing and longevity.

Time is of the essence: microRNAs and age-associated neurodegeneration

Aging is a key risk factor in neurodegenerative disease; however, little is known about cellular pathways that mediate age-associated degeneration of the brain. The Bonini lab has identified a conserved microRNA, miR-34, that plays a neuroprotective role in the aging Drosophila brain and suggests that it functions in temporal control of gene expression.

Micronutrient (Zn, Cu, Fe)-gene interactions in ageing and inflammatory age-related diseases: implications for treatments

In ageing, alterations in inflammatory/immune response and antioxidant capacity lead to increased susceptibility to diseases and loss of mobility and agility. Various essential micronutrients in the diet are involved in age-altered biological functions. Micronutrients (zinc, copper, iron) play a pivotal role either in maintaining and reinforcing the immune and antioxidant performances or in affecting the complex network of genes (nutrigenomic approach) involved in encoding proteins for a correct inflammatory/immune response. By the other side, the genetic inter-individual variability may affect the absorption and uptake of the micronutrients (nutrigenetic approach) with subsequent altered effects on inflammatory/immune response and antioxidant activity. Therefore, the individual micronutrient-gene interactions are fundamental to achieve healthy ageing. In this review, we report and discuss the role of micronutrients (Zn, Cu, Fe)-gene interactions in relation to the inflammatory status and the possibility of a supplement in the event of a micronutrient deficiency or chelation in presence of micronutrient overload in relation to specific polymorphisms of inflammatory proteins or proteins related of the delivery of the micronutriemts to various organs and tissues. In this last context, we report the protein-metal speciation analysis in order to have, coupled with micronutrient-gene interactions, a more complete picture of the individual need in micronutrient supplementation or chelation to achieve healthy ageing and longevity.

Transcriptional profiling of human familial longevity indicates a role for ASF1A and IL7R

The Leiden Longevity Study consists of families that express extended survival across generations, decreased morbidity in middle-age, and beneficial metabolic profiles. To identify which pathways drive this complex phenotype of familial longevity and healthy aging, we performed a genome-wide gene expression study within this cohort to screen for mRNAs whose expression changes with age and associates with longevity. We first compared gene expression profiles from whole blood samples between 50 nonagenarians and 50 middle-aged controls, resulting in identification of 2,953 probes that associated with age. Next, we determined which of these probes associated with longevity by comparing the offspring of the nonagenarians (50 subjects) and the middle-aged controls. The expression of 360 probes was found to change differentially with age in members of the long-lived families. In a RT-qPCR replication experiment utilizing 312 controls, 332 offspring and 79 nonagenarians, we confirmed a nonagenarian specific expression profile for 21 genes out of 25 tested. Since only some of the offspring will have inherited the beneficial longevity profile from their long-lived parents, the contrast between offspring and controls is expected to be weak. Despite this dilution of the longevity effects, reduced expression levels of two genes, ASF1A and IL7R, involved in maintenance of chromatin structure and the immune system, associated with familial longevity already in middle-age. The size of this association increased when controls were compared to a subfraction of the offspring that had the highest probability to age healthily and become long-lived according to beneficial metabolic parameters. In conclusion, an “aging-signature” formed of 21 genes was identified, of which reduced expression of ASF1A and IL7R marked familial longevity already in middle-age. This indicates that expression changes of genes involved in metabolism, epigenetic control and immune function occur as a function of age, and some of these, like ASF1A and IL7R, represent early features of familial longevity and healthy ageing.

Discovery of functional gene variants associated with human longevity: opportunities and challenges

Age is a major risk factor for many human diseases. Extremely long-lived individuals, such as centenarians, have managed to ward off age-related diseases and serve as human models to search for the genetic factors that influence longevity. The discovery of evolutionarily conserved pathways with major impact on life span in animal models has provided tantalizing opportunities to test the relevance of these pathways for human longevity. Here we specifically focus on the insulin/insulin-like growth factor-1 signaling as a prime candidate pathway. Coupled with the rapid advances in ultra high-throughput sequencing technologies, it is now feasible to comprehensively analyze all possible sequence variants in candidate genes segregating with a longevity phenotype and to investigate the functional consequences of the associated variants. A better understanding of the functional genes that affect healthy longevity in humans may lead to a rational basis for intervention strategies that can delay or prevent age-related diseases.