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Candidate gene studies and genome-wide association studies found that genetic variation in APOE is robustly associated with multiple age-related diseases and longevity. Apolipoprotein E (ApoE) is an apolipoprotein that plays an important role in triglyceride and cholesterol metabolism. In literature, especially the ApoE ɛ4 isoform has been associated with an increased risk of mortality and age-related diseases such as Alzheimer's disease (AD), cardiovascular diseases (CVD), as compared to the "neutral" ApoE ɛ3 isoform. There are, however, large differences in the deleterious effects of the ApoE ɛ4 isoform between ancestries and populations, which might be explained by differences in environmental and lifestyle exposures. In this respect, poor nutrition and physical inactivity are two important lifestyle factors that have been associated with increased risks for AD and CVD. Therefore, in this narrative review, we discuss how omega-3 fatty acid intake and physical activity may modify the impact of ApoE ɛ4 on AD and CVD risk.

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., (© The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Thresholds of optimal thyroid status in old age are controversial. We investigated the longitudinal association between thyroid parameters and 10-year all-cause mortality risk in older outpatients with normal thyrotropin (TSH) and modification by sex and age., Methods: Baseline TSH, free thyroxine (fT4), and free triiodothyronine (fT3) were assessed in the Milan Geriatrics 75+ Cohort Study. 324 men and 609 women older than 75 years had normal TSH. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for the associations between thyroid parameters and mortality risk using Cox regression. Sex-stratified analyses were adjusted for sociodemographic factors and comorbidities., Results: 233 men and 367 women died during follow-up. After adjustment, each 1-mU/L higher TSH was associated with decreased mortality risk in men (HR 0.83, 95% CI 0.69-0.98), but not in women (HR 1.09, 95% CI 0.95-1.24) (p for sex interaction = .006). Each 1-ng/L higher fT4 was associated with increased mortality risk in men (HR 1.11, 95% CI 1.02-1.22), but not in women (HR 0.98, 95% CI 0.93-1.04) (p for sex interaction = .013). Each 1-pg/mL higher fT3 was associated with decreased mortality risk in women (HR 0.77, 95% CI 0.60-0.98), but not in men (HR 0.80, 95% CI 0.57-1.13). The inverse association between TSH and mortality was most pronounced in men older than 85 years., Conclusions: Among older outpatients with normal TSH, higher TSH and lower fT4 were associated with decreased mortality risk in men but not in women. When assessing thyroid status, sex and age should be taken into account., (© The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Senescent cells are more prevalent in aged human skin compared to young, but evidence that senescent cells are linked to other biomarkers of aging is scarce. We counted cells positive for the tumor suppressor and senescence associated protein p16INK4a in sun-protected upper-inner arm skin biopsies from 178 participants (aged 45-81 years) of the Leiden Longevity Study. Local elastic fiber morphology, facial wrinkles, and perceived facial age were compared to tertiles of p16INK4a counts, while adjusting for chronological age and other potential confounders.The numbers of epidermal and dermal p16INK4a positive cells were significantly associated with age-associated elastic fiber morphologic characteristics, such as longer and a greater number of elastic fibers. The p16INK4a positive epidermal cells (identified as primarily melanocytes) were also significantly associated with more facial wrinkles and a higher perceived age. Participants in the lowest tertile of epidermal p16INK4a counts looked 3 years younger than those in the highest tertile, independently of chronological age and elastic fiber morphology.In conclusion, p16INK4a positive cell numbers in sun-protected human arm skin are indicative of both local elastic fiber morphology and the extent of aging visible in the face., (© The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: As facial appearance can be readily quantified and skin tissue easily accessed, they could be valuable tools for determining how biological mechanisms influence tissue degeneration with age and, consequently, human health and lifespan. It is unknown, however, whether appearance reflects disease risk or lifespan independently of factors already known to associate with both health and appearance., Methods: In a cross-sectional study, we compared the amount of skin wrinkling on a sun-protected site (upper inner arm) and the facial appearance of 261 offspring (mean age 63.2 y) of nonagenarian siblings with 253 age-matched controls (mean age 62.7 y), all with no reported disease history. We next examined whether any appearance features that significantly associated with familial longevity also associated with the Framingham cardiovascular disease (CVD) risk score. All analyses were adjusted for chronological age, smoking, photodamage, and body mass index., Results: Female and male offspring had reduced upper inner arm skin wrinkling (p = .03 and p < .001, respectively), and the male offspring looked 1.4 y younger than the controls (p = .002). There were no significant associations between CVD risk and upper inner arm skin wrinkling. Women in the lowest quartile of CVD risk looked more than 2 y younger for their age than those in higher risk quartiles (p = .002). Systolic blood pressure was the most significant (p = .004) CVD risk factor that was associated with perceived age in women., Conclusions: Facial appearance and skin wrinkling at a sun-protected site reflect the propensity to reach an extreme old age, and facial appearance reflects the risk of succumbing to CVD independently of chronological age, smoking, photodamage, and BMI.

Respiratory chain function becomes less efficient with age resulting in increased levels of damaging reactive oxygen species. We compared rotenone-exposed fibroblast strains from young and old subjects and from offspring of nonagenarian siblings and the partners of the offspring. Rotenone increased reactive oxygen species levels, inhibited growth rate, and increased telomere shortening (all p < .05). Non-stressed strains from young subjects showed lower reactive oxygen species levels (p = .031) and higher growth rates (p = .002) than strains from old subjects. Stressed strains from young subjects showed smaller increases in reactive oxygen species levels (p = .014) and larger decreases in growth rate (p < .001) than strains from old subjects. Telomere-shortening rates were not different between groups. Stress-induced decreases in growth rate were larger in strains from offspring than from partners (p = .05). Strains from young and old subjects are differentially affected by chronic inhibition of the respiratory chain. Changed growth rates in strains from offspring resemble those from strains from young subjects.

Cellular senescence, an important factor in ageing phenotypes, can be induced by replicative exhaustion or by stress. We investigated the relation between maximum replicative capacity, telomere length, stress-induced cellular senescence, and apoptosis/cell death in human primary fibroblast strains obtained from nonagenarians of the Leiden 85-plus Study. Fibroblast strains were cultured until replicative senescence and stressed with rotenone at low passage. Telomere length, senescence-associated-β-galactosidase activity, sub-G1 content, and Annexin-V/PI positivity were measured in nonstressed and stressed conditions. Fibroblast strains with a higher replicative capacity had longer telomeres (p = .054). In nonstressed conditions, replicative capacity was not associated with β-gal activity (p = .07) and negatively with sub-G1 (p = .008). In rotenone-stressed conditions, replicative capacity was negatively associated with β-gal activity (p = .034) and positively with sub-G1 (p = .07). Summarizing, fibroblast strains with a higher maximum replicative capacity have longer telomeres, are less prone to go into stress-induced cellular senescence, and more prone to die after stress.

Background: In contrast to middle age, higher body mass index (BMI), cholesterol levels, and blood pressures associate no longer with increased mortality in old age. With increasing age, these risk factors are prone to change over time. It is unclear whether dynamics of these traditional metabolic risk factors in late life associate with mortality and whether they occur in concert with each other., Methods: Within the Leiden 85-plus Study, a prospective population-based study of 599 participants aged 85 years, participants were annually assessed during a 5-year follow-up period and observed for mortality for 10 years., Results: BMI, total cholesterol levels, glucose levels, and blood pressures declined and HDL cholesterol levels increased between ages 85 and 90 years (all p < .005). Participants who died at age 90 years had stronger annual declines in BMI, total cholesterol levels, and diastolic blood pressure and weaker increases in HDL cholesterol levels than participants who survived until the end of follow-up (all p < or = .001). In a principal component analysis, annual changes in total, LDL, and HDL cholesterol levels; blood pressures; and glucose, albumin, hemoglobin, leukocyte, and C-reactive protein levels grouped together in one component (all correlation r with component >.40), which associated with all-cause and cancer mortality., Conclusions: In old age, larger declines in BMI, total cholesterol levels, and blood pressures and weaker increases in HDL cholesterol levels associate with mortality. We identified distinct clustering in the dynamics of these traditional metabolic risk factors and indicators of health and disease in a profile that is suggestive of underlying wasting disease.

Background: The hypothalamo-pituitary-thyroid axis has been widely implicated in modulating the aging process. Life extension effects associated with low thyroid hormone levels have been reported in multiple animal models. In human populations, an association was observed between low thyroid function and longevity at old age, but the beneficial effects of low thyroid hormone metabolism at middle age remain elusive., Methods: We have compared serum thyroid hormone function parameters in a group of middle-aged offspring of long-living nonagenarian siblings and a control group of their partners, all participants of the Leiden Longevity Study., Results: When compared with their partners, the group of offspring of nonagenarian siblings showed a trend toward higher serum thyrotropin levels (1.65 vs157 mU/L, p = .11) in conjunction with lower free thyroxine levels (15.0 vs 15.2 pmol/L, p = .045) and lower free triiodothyronine levels (4.08 vs 4.14 pmol/L, p = .024)., Conclusions: Compared with their partners, the group of offspring of nonagenarian siblings show a lower thyroidal sensitivity to thyrotropin. These findings suggest that the favorable role of low thyroid hormone metabolism on health and longevity in model organism is applicable to humans as well.

An accumulating body of evidence suggests the involvement of an evolutionary conserved insulin/insulin-like growth factor-1 (IGF-1) signaling (IIS) pathway in the regulation of the life and health span in nematodes, flies, rodents, and humans. We studied the association between insulin/IGF-1 signaling and cognitive function among 1015 participants, 85 years old or older, of the population-based Leiden 85-Plus Study. A composite IIS6 score, based on expected effects (increased or decreased signaling) of selected variants in the IIS pathway, was calculated to estimate IIS pathway activity. Cognitive function was assessed at baseline and annually during a 5-year follow-up, using the Mini-Mental State Examination (MMSE). In women, but not in men, lower IIS6 scores (indicating decreased signaling) were associated with a lower risk of cognitive impairment (MMSE score

Replicative senescence of human fibroblasts in vitro has been used as a model for in vivo aging. The onset of replicative senescence varies between several months to years. A colony formation assay, critically dependent on growth speed, can be performed within weeks, and has been reported being an indicator for the onset of replicative senescence. Earlier we could not find a correlation between growth speed in mass cultures and onset of replicative senescence of human fibroblast strains. Therefore, we studied the colony formation assay in 23 fibroblast strains that varied widely in their replicative capacity. Neither the number nor the size of colonies was related to the onset of replicative senescence. The number of cells within the colonies was modestly correlated to the growth speed of the mass cultures. We conclude that the colony formation assay does not reflect the onset of replicative senescence in human fibroblasts.

The high-density lipoprotein (HDL) constituent apolipoprotein CI (apoCI) protects mice against mortality in bacterial sepsis. We assessed whether high plasma apoCI levels protect against mortality from infection in humans. We determined plasma levels of apoCI, lipids, and C-reactive protein in 85-year-old participants of the prospective population-based Leiden 85-Plus Study (n = 561). Participants were followed for specific causes of death. High apoCI levels were associated with 40% reduced risk of mortality from infection (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.42-0.86; p =.005) for every increase of 1 standard deviation in apoCI level. A similar association was observed for high HDL cholesterol (HR, 0.65; 95% CI, 0.46-0.94; p =.022), but not for LDL cholesterol, triglycerides, and C-reactive protein levels. The association of apoCI was independent of HDL cholesterol, as multivariate analysis did not alter the association for apoCI (HR, 0.63; 95% CI, 0.44-0.90; p =.013), whereas for HDL cholesterol significance was lost. We conclude that high apoCI levels are associated with reduced mortality from infection, in line with experimental evidence in rodents.

The (Silent Information Regulator 2) Sir2 gene has been shown to regulate the life span of several model organisms. In mammals, the evolutionarily conserved homologue (Sirtuin 1) SIRT1 regulates neuroprotection, metabolism, and cell survival in response to stress. Based on these data, we hypothesized that SIRT1 might influence the prevalence of age-related diseases and modify the life span of humans. In order to test this, we genotyped five single nucleotide polymorphisms (SNPs) in 1245 participants of the population-based Leiden 85-plus Study. SIRT1 haplotypes were assessed and tested for association with the risks of mortality, metabolic profile, age-related diseases, and cognitive functioning. These analyses revealed a trend for lower cardiovascular mortality for haplotype 2 and rs3758391 SNP carriers. In further analyses, this trend was not supported by intermediate phenotypes, albeit the rs3758391 T-allele carriers had better cognitive functioning. In conclusion, our results indicate a role for SIRT1 in cognitive functioning, but the role in life span remains to be elucidated.

In the nematode Caenorhabditis elegans, nuclear hormone receptor DAF-12 regulates the decision to go into a resistant dauer diapause, in which the worm exhibits a decreased rate of aging. Using sequence similarity searches, we previously identified the liver X receptor alpha (LXRalpha) as one of the human nuclear hormone receptors the protein sequence of which is most similar to C. elegans DAF-12. Here, we studied whether variation in the gene encoding LXRalpha associates with human life span. In the Leiden 85-Plus Study, a population-based prospective follow-up study, we genotyped four polymorphisms spanning the gene coding for LXRalpha (NR1H3) and tagged four common haplotypes. Among 563 participants, haplotype 2 associated with reduced mortality during the 7-year follow-up (hazard ratio 0.78; p =.015), predominantly caused by reduced mortality from infectious disease (hazard ratio 0.31; p =.023). Haplotype 2 also associated with higher levels of plasma apolipoprotein E, a target gene of the LXRalpha (p =.018), and higher levels of triglycerides (p =.041). Genetic variation in the gene coding for the LXRalpha (NR1H3) associates with human life span.