The genetics of exceptional longevity: Insights from centenarians

Autoimmunity in centenarians. A paradox

Autoimmune diseases (ADs) are one of the groups of chronic illnesses that impose a significant burden of disease and health costs worldwide. Age is a crucial risk factor for the onset of ADs. Theoretically, it is inferred that with organic and immune system aging, the loss of immune tolerance and specificity of immune activity becomes more intense, the probability of autoimmunity is increasing. However, there is a group of individuals whose prevalence of ADs is very low or non-existent, despite the biological aging. This paradox in autoimmunity raises questions. Centenarians, individuals who are over 100 years old, are possibly the most successful model of biological aging in humans. Most of these individuals exhibit a favorable health phenotype. To date, primary data evidence and potential hypotheses explaining this phenomenon are lacking globally, even though this paradox could provide valuable, original, and relevant information regarding the understanding of risk or protective factors, biological drivers, and biomarkers related to autoimmunity. Herein we discuss some hypothesis that may explain the absence of ADs in centenarians, including inflammaging, immunosenescence and immune resilience, immune system hyperstimulation, proteodynamics, and genetics.

Physical Condition and Risk of Hospitalization and Polypharmacy in Older Adults

Hospitalization in older population leads to a decline in physical function, physical condition and independency. However, a scarce number of studies has addressed the effect of being in good physical condition on the risk of hospitalization and polypharmacy in older people. Therefore, this study aims to examine the relationship between physical condition and other health factors, and the incidence of hospitalization and polypharmacy in Spanish older persons. For this cross-sectional study 102 community-dwelling persons aged 80 years or older who were being treated at three primary care centers. The data collected were number of hospitalizations and medications, dietary habits, nutrition status, quality of life, independence in activities of daily life, physical performance and associated genotype data. Scoring higher in the tests Chair stand and 8-Foot Up-and-go was found associated with reduced risks of hospitalization [OR = .45 (95% CI = .2, .99); OR .32 (95% CI = .12, .86)] and polypharmacy [OR = .36 (95% CI = .16, .8); OR= .28 (95% CI = .1, .78)]. The number of medications was also lower in individuals with a greater aerobic capacity and activities of daily life independence [OR = .28 (95% CI = .1, .78); OR = .37 (95% CI = .16, .82)]. No associations were found with the remaining physical performance tests or other factors assessed. Our findings point to benefits of greater strength, balance and aerobic capacity in terms of reducing the risk of hospitalization and polypharmacy.

Association between Circulating Antioxidants and Longevity: Insight from Mendelian Randomization Study

Background. Antioxidants attracted long-standing attention as promising preventive agents worldwide. Previous observational studies have reported that circulating antioxidants are associated with reduced mortality; however, randomized clinical trials indicate neutral or harmful impacts. The association of long-term circulating antioxidant exposure with longevity is still unclear. Objectives. We aim to determine whether long-term circulating antioxidant exposure is causally associated with longevity in the general population using the two-sample Mendelian randomization (MR) design. Methods. Genetic instruments for circulating antioxidants (ascorbate, lycopene, selenium, beta-carotene, and retinol) and antioxidant metabolites (ascorbate, alpha-tocopherol, gamma-tocopherol, and retinol) were identified from the largest up-to-date genome-wide association studies (GWASs). Summary statistics of these instruments with individual survival to the 90th vs. 60th percentile age (11,262 cases and 25,483 controls) and parental lifespan ( $N=\mathrm{1,012,240}$ individuals) were extracted. The causal effect was estimated using the inverse-variance weighted method in the main analysis and complemented by multiple sensitivity analyses to test the robustness of results. Results. We found that genetically determined higher concentration of circulating retinol (vitamin A) metabolite was casually associated with a higher odds of longevity (OR, 1.07; 95% CI, 1.02–1.13; $P<0.01$ ) and increased parental lifespan (lifespan years per 10-fold increase: 0.17; 95% CI, 0.07–0.27; $P<0.01$ ). Present evidence did not support a causal impact of circulating ascorbate (vitamin C), tocopherol (vitamin E), lycopene, selenium or beta-carotene on life expectancy. No evidence was identified to show the pleiotropic effects had biased the results. Conclusions. Long-term higher exposure to retinol metabolite is causally associated with longevity in the general population. Future MR analyses could assess the current findings further by utilizing additional genetic variants and greater samples from large-scale GWASs.

A description of the relationship in healthy longevity and aging-related disease: from gene to protein

Human longevity is a complex phenotype influenced by both genetic and environmental factors. It is also known to be associated with various types of age-related diseases, such as Alzheimer's disease (AD) and cardiovascular disease (CVD). The central dogma of molecular biology demonstrates the conversion of DNA to RNA to the encoded protein. These proteins interact to form complex cell signaling pathways, which perform various biological functions. With prolonged exposure to the environment, the in vivo homeostasis adapts to the changes, and finally, humans adopt the phenotype of longevity or aging-related diseases. In this review, we focus on two different states: longevity and aging-related diseases, including CVD and AD, to discuss the relationship between genetic characteristics, including gene variation, the level of gene expression, regulation of gene expression, the level of protein expression, both genetic and environmental influences and homeostasis based on these phenotypes shown in organisms.

Genetics of Menopause and Primary Ovarian Insufficiency: Time for a Paradigm Shift?

This review summarizes the existing information concerning the genetic background of menopause and primary ovarian insufficiency (POI). There is overwhelming evidence that majority of genes are involved in double-strand break repair, mismatch repair, and base excision repair. The remaining loci were involved in cell energy metabolism and immune response. Gradual (or in case of rapid POI) accumulation of unrepaired DNA damage causes (premature) cell death and cellular senescence. This in turn leads to exhaustion of cell renewal capacity and cellular dysfunction in affected organs and eventually to aging of the entire soma. Similar erosion of the genome occurs within the germ cell line and the ovaries. Subsequently, the systemic "survival" response intentionally suppresses the sex-steroid hormonal output, which in turn may contribute to the onset of menopause. The latter occurs in particular when age-dependent DNA damage accumulation does not cease. Both effects are expected to synergize to promote (premature) ovarian silencing and install (early) menopause. Consequently, aging of the soma seems to be a primary driver for the loss of ovarian function in women. This challenges the current dogma which implies that loss of ovarian function initiates aging of the soma. It is time for a paradigm shift!

Whole-genome sequencing of Chinese centenarians reveals important genetic variants in aging WGS of centenarian for genetic analysis of aging

Background

Genetic research on longevity has provided important insights into the mechanism of aging and aging-related diseases. Pinpointing import genetic variants associated with aging could provide insights for aging research.

Methods

We performed a whole-genome sequencing in 19 centenarians to establish the genetic basis of human longevity.

Results

Using SKAT analysis, we found 41 significantly correlated genes in centenarians as compared to control genomes. Pathway enrichment analysis of these genes showed that immune-related pathways were enriched, suggesting that immune pathways might be critically involved in aging. HLA typing was next performed based on the whole-genome sequencing data obtained. We discovered that several HLA subtypes were significantly overrepresented.

Conclusions

Our study indicated a new mechanism of longevity, suggesting potential genetic variants for further study.

Desarrollo evolutivo humano y longevidad. Un análisis bio-psicosocial

En este trabajo se hace una revisión bibliográfica sobre el desarrollo evolutivo humano y longevidad, desde un enfoque biopsicosocial (Engel, 1977; Gliedt et al., 2017; Lehman et al., 2017). Tras aplicar el método de análisis PRISMA, se obtuvieron diversos resultados relacionados con un desarrollo evolutivo más longevo; así, en el área biológica, 3 factores: los SNPs, los telómeros y la química del estrés; en el área psicológica, 5 factores: la metacognición, la resiliencia, la espiritualidad, las relaciones personales y la depresión; y en el área social, 8 factores: la pseudo-heredabilidad, las relaciones conyugales, la maternidad, el nivel educativo, estilos de vida, dieta y restricción calórica, actividad física y mental y tecnología sanitaria. Ante los datos obtenidos en las tres áreas, de este enfoque biopsicosocial, y el repetido solapamiento entre factores del área psicológica y del área social, se plantea que pudieran considerarse estas dos como una conjunta, proponiéndose un enfoque explicativo con dos áreas: bio-psicosocial que, por factores encontrados en este trabajo, quedarían un 18,7% de biológica y un 81,3% psicosocial. Actualmente, hay suficiente información sobre desarrollo evolutivo humano y longevidad, pero una ausencia de investigaciones que estudien esos factores desde una perspectiva integrada. Mucha de esa información privilegiada se podría aplicar ya, psicológica y socialmente, a la población en general, para una mejora de su salud, en cualquier fase del desarrollo evolutivo humano.

Successful aging: insights from proteome analyses of healthy centenarians

Healthy aging depends on a complex gene-environment network that is ultimately reflected in the expression of different proteins. We aimed to perform a comparative analysis of the plasma proteome of healthy centenarians (n=9, 5 women, age range 100–103 years) with a notably preserved ambulatory capacity (as a paradigm of ‘successful’ aging), and control individuals who died from a major age-related disease before the expected life expectancy (n=9, 5 women, age range: 67–81 years), and while having impaired ambulatory capacity (as a paradigm of ‘unsuccessful’ aging). We found that the expression of 49 proteins and 86 pathways differed between the two groups. Overall, healthy centenarians presented with distinct expression of proteins/pathways that reflect a healthy immune function, including a lower pro-inflammatory status (less ‘inflammaging’ and autoimmunity) and a preserved humoral immune response (increased B cell-mediated immune response). Compared with controls, healthy centenarians also presented with a higher expression of proteins involved in angiogenesis and related to enhanced intercellular junctions, as well as a lower expression of proteins involved in cardiovascular abnormalities. The identification of these proteins/pathways might provide new insights into the biological mechanisms underlying the paradigm of healthy aging.

Centenarians: An excellent example of resilience for successful ageing

Centenarians are remarkable not only because of their prolonged life, but also because they compress morbidity until the very last moments of their lives, thus being proposed as a model of successful, extraordinary ageing. From the medical viewpoint, centenarians do not escape the physiological decline or the age-related diseases or syndromes (i.e. frailty), but the rate of such processes is slow enough to be counterbalanced by their increased intrinsic capacity to respond to minor stresses of daily life (i.e. resilience). These new concepts are reviewed in this paper. Allostatic stresses lead to a chronic low-grade inflammation that has led to the proposal of the "inflammaging" theory of ageing and frailty. The biology of centenarians, described in this review, provides us with clues for intervention to promote healthy ageing in the general population. One of the major reasons for this healthy ageing has to do with the genetic signature that is specific for centenarians and certainly different from octogenarians who do not enjoy the extraordinary qualities of centenarians.

Physical Activity and Sedentary Behavior at the End of the Human Lifespan

To objectively assess physical activity levels and sedentary behavior in a cohort of Spanish centenarians and their nonagenarian peers. Physical activity and sedentary behavior patterns were objectively measured by an ActiGraph GT3X accelerometer in centenarians (n = 18; 83% women; 100.8 ± 0.8 [100-103] years) and nonagenarians (n = 11; 91% women; 93.3 ± 2.5 [90-98] years). Centenarians showed less counts per minute (17.6 ± 7.1 vs. 46.1 ± 23.7, p = .003, d = 1.851) and steps per day (455 ± 237 vs. 1,249 ± 776, p = .007, d = 1.587) than nonagenarians. The daily number of sedentary breaks was also lower in the former (5.0 ± 1.5 vs. 6.7 ± 2.0, p = .019, d = 0.971). When observing time distribution, the most active day period in both groups was the morning, with a peak between 10:00 and 11:59. This data suggest that the decline in physical activity levels continues to worsen until the end of the human lifespan.

Genetic background, epigenetic factors and dietary interventions which influence human longevity

Longevity is mainly conditioned by genetic, epigenetic and environmental factors. Different genetic modifications seem to be positively associated to longevity, including SNPs in SIRT1, APOE, FOXO3A, ACE, ATM, NOS1 and NOS2 gene. Epigenetic changes as DNA hyper- and hypo-methylation influence significantly human longevity by activating/deactivating different genes involved in physiological mechanisms. Several studies have confirmed that centenarians have a lower DNA methylation content compared to young subjects, which showed more homogeneously methylated DNA region. Also the up-regulation of miR-21 seems to be more associated with longevity in different populations of long-lived subjects, suggesting its role as potential epigenetic biomarkers. A non-pharmacological treatment that seems to contrast age-related diseases and promote longevity is represented by dietary intervention. It has been evaluated the effects of dietary restriction of both single nutrients or total calories to extend lifespan. However, in daily practice it is very difficult to guarantee adherence/compliance of the subjects to dietary restriction and at the same time avoid dangerous nutritional deficiencies. As consequence, the attention has focused on a variety of substances both drugs and natural compounds able to mime the beneficial effects of caloric restriction, including resveratrol, quercetin, rapamycin, metformin and 2-deoxy-D-glucose.

Genetic and epigenetic regulation of human aging and longevity

Here we summarize the latest data on genetic and epigenetic contributions to human aging and longevity. Whereas environmental and lifestyle factors are important at younger ages, the contribution of genetics appears more important in reaching extreme old age. Genome-wide studies have implicated ~57 gene loci in lifespan. Epigenomic changes during aging profoundly affect cellular function and stress resistance. Dysregulation of transcriptional and chromatin networks is likely a crucial component of aging. Large-scale bioinformatic analyses have revealed involvement of numerous interaction networks. As the young well-differentiated cell replicates into eventual senescence there is drift in the highly regulated chromatin marks towards an entropic middle-ground between repressed and active, such that genes that were previously inactive "leak". There is a breakdown in chromatin connectivity such that topologically associated domains and their insulators weaken, and well-defined blocks of constitutive heterochromatin give way to generalized, senescence-associated heterochromatin, foci. Together, these phenomena contribute to aging.

Ageing, Disability, and Spinal Cord Injury: Some Issues of Analysis

Spinal cord injury is a disabling disorder, worldwide spread, with important consequences on functioning and health conditions and impacts on physical, psychological, and social well-being. The consequences are related to the lesion itself and to other complications related to the lesion. In the last decades, there have been an increasing of the mean ages of onset and also an increase in life expectancy after the lesion. So, differently from the past, people with spinal cord injury can age after the lesion. Taking into account the need to share data and information about specific disabling conditions and their relationship with ageing, this paper aims to discuss some issues from recent literature on the relationship between aging and disability in the spinal cord injury, according to a narrative review approach. A narrative review of the literature on ageing and spinal cord injury was undertaken. Search was based on the following electronic databases: PubMed/Medline and Ovid/PsychINFO. A combination of the following keywords was used: (1) “ageing” or “aging” and (2) “spinal cord injury” or “spinal cord lesion” and (3) disability. Data on consequences of the lesion in the life of aging people, secondary health conditions, life expectancy, participation, and quality of life are discussed. Then, a brief discussion of clinical issues and the role of interventions aimed to promote wellbeing, health, quality of life, and participation of people with spinal cord injury is proposed.

Conserved signaling pathways genetically associated with longevity across the species

Advanced age is an independent risk factor for natural death and common diseases, such as cardiovascular diseases, dementia, and cancers, which are life-threatening and cause disabilities. On the other hand, individual with healthy longevity is a plausible model for successful aging. Thus, search for longevity-associated genes and pathways likely provides a unique approach to understand the genetic mechanisms underlying aging and healthspan, and emerging evidence from model organisms has highlighted the significance of genetic components in longevity. Here we reviewed the uses of model organisms including yeast, ciliate, nematode, arthropod, fish, rodent, and primate as well as human to identify the genetic determinants of longevity and discussed the genetic contributions of conserved longevity pathways, such as adrenergic system, AMPK, insulin/IGF-1, and mTOR signaling pathways.

Genetic cartography of longevity in humans and mice: Current landscape and horizons

Aging is a complex and highly variable process. Heritability of longevity among humans and other species is low, and this finding has given rise to the idea that it may be futile to search for DNA variants that modulate aging. We argue that the problem in mapping longevity genes is mainly one of low power and the genetic and environmental complexity of aging. In this review we highlight progress made in mapping genes and molecular networks associated with longevity, paying special attention to work in mice and humans. We summarize 40 years of linkage studies using murine cohorts and 15 years of studies in human populations that have exploited candidate gene and genome-wide association methods. A small but growing number of gene variants contribute to known longevity mechanisms, but a much larger set have unknown functions. We outline these and other challenges and suggest some possible solutions, including more intense collaboration between research communities that use model organisms and human cohorts. Once hundreds of gene variants have been linked to differences in longevity in mammals, it will become feasible to systematically explore gene-by-environmental interactions, dissect mechanisms with more assurance, and evaluate the roles of epistasis and epigenetics in aging. A deeper understanding of complex networks-genetic, cellular, physiological, and social-should position us well to improve healthspan.

Effect of age, period and birth-cohort on the frequency of glucose-6-phosphate dehydrogenase deficiency in Sardinian adults

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an inherited disorder common in Sardinia. In this study, the frequency variation of G6PD-deficiency across age groups and birth cohorts was investigated using Age-Period-Cohort analysis.

METHODS

Data were collected from the clinical records of 11,252 patients (6975 women, age range 17-94 years) who underwent endoscopy between 2000 and 2016 at a teaching hospital (University of Sassari), Italy. G6PD status was assessed by enzymatic assay based on G6PD/6GPD ratio. A Poisson log-linear regression model was used to identify age and time trend in G6PD deficiency.

RESULTS

Enzyme deficiency was detected in 11.4% of the entire cohort (men: 7.9%; women: 13.6%). Age-Period-Cohort analysis showed no inflection points across age groups, especially after age 80. The effects of time period and birth cohorts on G6PD deficiency were negligible (frequencies before and after 1950 were 11.0% and 11.8%, respectively).

CONCLUSIONS

These findings indicate that the frequency of G6PD deficiency does not vary significantly in oldest subjects. The lack of evidence for selection across the malaria eradication time may be explained by other factors, including somatic cell selection or misclassification of heterozygotes women as G6PD normal in the older birth cohorts. Additional molecular studies may help clarify these issues. Key message The frequency of glucose-6-phosphate dehydrogenase deficiency is stable across age groups and does not vary in generations born before or after malaria eradication.

rs2802292 polymorphism in the FOXO3A gene and exceptional longevity in two ethnically distinct cohorts

OBJECTIVES

Previous studies have indicated that the rs2802292 polymorphism in the human forkhead box O3A (FOXO3A) gene might be associated with exceptional longevity (EL, i.e., living 100+ years), although the results are conflicting.

STUDY DESIGN AND MAIN OUTCOME MEASURES

Using a case-control design, we investigated the distribution of the rs2802292 polymorphism in two ethnically distinct cohorts of centenarians (cases) and younger adults (controls). The first cohort included Japanese individuals (733 centenarians and 820 controls) and the second was from Northern Italy (79 disease-free centenarians and 316 controls).

RESULTS

No statistically significant association was found between the rs2802292 polymorphism and EL in either cohort (either examined in their entirety or in a sex-based analysis).

CONCLUSIONS

In light of our negative findings, further research and resequencing efforts are needed to shed more light on the potential association between EL and FOXO3A polymorphisms.