A third of those over 80 years of age are likely to have dementia, the lack of a cure requires efforts directed at prevention and delaying the age of onset. We argue here for the importance of understanding the cognitive ageing process, seen as the decline in various cognitive functions from adulthood to old age. The impact of age on cognitive function is heterogeneous and the identification of risk factors associated with adverse cognitive ageing profiles would allow well-targeted interventions, behavioural or pharmacological, to delay and reduce the population burden of dementia. A shift away from binary outcomes such as dementia assessed at one point in time in elderly populations to research on cognitive ageing using repeated measures of cognitive function and starting earlier in the life course would allow the sources of variability in ageing to be better understood.
Alzheimer’s disease; Dementia; Cognitive ageing
A third of those over 80 years of age are likely to have dementia, the lack of a cure requires efforts directed at prevention and delaying the age of onset. We argue here for the importance of understanding the cognitive ageing process, seen as the decline in various cognitive functions from adulthood to old age. The impact of age on cognitive function is heterogeneous and the identification of risk factors associated with adverse cognitive ageing profiles would allow well targeted interventions, behavioural or pharmacological, to delay and reduce the population burden of dementia. A shift away from binary outcomes such as dementia assessed at one point in time in elderly populations to research on cognitive ageing using repeated measures of cognitive function and staring earlier in the lifecourse would allow the sources of variability in ageing to be better understood.
Aging; Alzheimer Disease; epidemiology; physiopathology; Cognition; Dementia; diagnosis; epidemiology; physiopathology; prevention & control; therapy; France; epidemiology; Humans; Prevalence; Risk Factors; World Health Organization
Verbal comprehension is critical to the success of medical counseling. Here, we tested how age and vascular risk factors affect the ability to understand complex instructions. Verbal comprehension, cognitive functions, and vascular risk factors were assessed in 39 mid- and 38 late-life community-dwelling individuals (48 to 59 years and >59 years of age, respectively). To test for verbal comprehension, we used a modified version of the Token Test (TT). In midlife individuals, education (β = 0.572, p < 0.05) was the only predictor for extended-TT performance. In late-life individuals, age (β = −1.015, p < 0.001) and body mass index (β = −0.651, p = 0.003) were significantly correlated with extended-TT performance and explained 50% of the variance in extended-TT performance (adjusted R2 = 0.503). This relation is only partly explained by conventional neuropsychological measures as the ones used in our test battery. These results indicate that aging and overweight impair comprehension of complex instructions. Therefore, medical counseling appropriate for midlife individuals may be less successful in elderly people and particularly in those with metabolic disturbances.
Token test; Language comprehension; Age; Vascular risk factor; Medical counseling
We studied the A55T, E164K, I225T, K153R and P198A variants in the myostatin (GDF8) gene, muscle strength and mass, and physical function during daily living in 41 nonagenarians [33 women, age range, 90, 97]. No participant carried a mutant allele of the aforementioned variants, except three participants (all women), who carried the R allele of the K153R polymorphism, with one of them (woman aged 96 years) being homozygous. Overall, in KR women muscle phenotype values (1RM leg press and estimated muscle mass) were low-to-normal compared to the whole group (∼25th–50th percentile), and their functional capacity (Barthel and Tinetti tests) was normal. In the woman bearing the RR genotype, values of muscle mass and functional capacity were below the 25th percentile. She is the first RR Caucasian whose phenotype has been characterised specifically. In summary, heterozygosity for the GDF8 K153R polymorphism does not seem to exert a negative influence on the muscle phenotypes of women who are at the end of the human lifespan, yet homozygosity might do so. More research on larger cohorts of nonagenarians is needed to corroborate the present findings.
Activities of daily living; GDF-8; Muscle strength; Nonagenarians
The average human lifespan has increased throughout the last century due to the mitigation of many infectious diseases. More people now die of age-related diseases than ever before, but these diseases have been resistant to elimination. Progress has been made in treatments and preventative measures to delay the onsets of these diseases, but most cancers and vascular diseases are still with us and they kill about the same fraction of the population year after year. For example, US Caucasian female deaths from breast plus genital cancers have remained a fairly constant ~7% of the age-related disease deaths from 1938 to 1998 and have been consistently ~2-fold greater than female colon plus rectal cancer deaths over that span. This type of stability pattern pervades the age-related diseases and suggests that intrinsic properties within populations determine these fractions. Recognizing this pattern and deciphering its origin will be necessary for the complete understanding of these major causes of death. It would appear that more than the random processes of aging drive this effect. The question is how to meaningfully approach this problem. This commentary discusses the epidemiological and aging perspectives and their current limitations in providing an explanation. The age of bioinformatics offers hope, but only if creative systems approaches are forthcoming.
Disease; Aging; Epidemiology; Bioinformatics; Genetics; Failure mechanisms
The high-growth (HG) phenotype in mice is characterized by a 30–50% postweaning overgrowth with a substantial increase in plasma insulin-like growth factor I (IGF1) levels, which is directly related to a deletion (hg) on chromosome 10 that includes the suppressor of cytokine signaling 2 (Socs2) gene. Reduced plasma IGF1 levels have been associated with extended lifespan in mice, although the aging-related effects of abnormally high IGF1 levels without elevated growth hormone levels have never been assessed in mammals. Within this context, the hg deletion was introgressed into C57BL/6J (B6) and FVB backgrounds, and a survival analysis was performed on the longevity records of 200 B6 (91 wild-type and 109 homozygous hg mutants) and 69 FVB (32 wild-type and 37 hg mutants) mice. Longevity was examined using a piecewise Weibull proportional hazards model solved through a Bayesian perspective and Markov chain Monte Carlo sampling. Lifespan was significantly reduced in both strains in homozygous hg mice, with a death risk between 3.689 (B6) and 4.347 (FVB) times higher than in wild-type mice (non-overlapped highest posterior density regions at 95%). These results highlight the effects of the Socs2 gene on aging regulation, likely related with variations described in plasma IGF1 levels. This result is consistent with previous research in dwarf mutant mice and other species, and characterizes the HG mutant mice as a unique and interesting animal model for accelerated aging research.
Cytokine signaling 2; Growth hormone; Insulin-like growth factor I; Lifespan; Mice; Survival analysis
Receptor-interacting protein (RIP) is a well-characterized coregulator for nuclear receptors. Here, we report the expression of RIP as two isoforms with molecular weights of 140 kDa and 137 kDa in liver and kidney, but only as one isoform of 140 kDa in lung, adipose tissue, prostate and testis of mice. The levels of both the isoforms decreased in liver and kidney of old mice compared with adult mice. The expression of RIP140 in kidney was relatively lower in old males than females. In contrast, adipose tissue showed remarkably higher levels of RIP140 in old than adult mice of both sexes. Thus, the expression of RIP varied with the type of tissue, sex and age of mice, suggesting differences in its function as a coregulator.
Receptor-interacting protein; Coregulator; Expression; Aging; Sex; Mouse
Microarray-based comparisons of long-lived and normal mouse strains represent a promising approach for dissecting the basis of lifespan extension in higher organisms. Recently, Boylston et al. (2006) generated a genome-wide data set that allowed expression levels of Snell (Pit1dw/dw) and Ames (Prop1df/df) long-lived mice to be compared with age-matched control mice across different ages (6–24 months). Longevity-associated genes were identified as those genes exhibiting differential expression between long-lived and normal mice at every age examined. In this communication, an alternative approach to identifying longevity-associated genes is suggested and applied to the data sets considered by Boylston et al. (2006). Longevity-associated genes are defined as those exhibiting significant genotype-by-age interaction with respect to expression levels of long-lived and normal mice, and a total of 63 longevity-associated genes are identified. This approach may lend greater confidence to the inference that expression of identified genes specifically underlies aging differences between long-lived and normal genotypes.
Aging; Ames; Dwarf; Lifespan; Microarray; Pit1dw; Prop1df; Snell
We considered a Gompertzian model for the population dynamics of Eisenia andrei case-cohorts in artificial OECD soil under strictly controlled conditions. The earthworm culture was kept between 18 and 22°C at a constant pH of 5.0. In all, 77 lumbricids were carefully followed for almost 9 years, until the oldest died. The Eisenia median longevity is 4.25 years and the oldest specimen was 8.73 years. Eisenia cocoons were hand-sorted every 3 weeks, washed in distilled water, placed in Petri dishes, and counted. Regular removal did not reduce breeding. Each fertile cocoon contained on average two or three embryos. The failure rates (mortality and infertility percentages) are smooth power functions where the rate at time (n + 1) captured most of the phenomenology of the previous rate at time n, as expected by the considered law, but not at both the beginning and the end of this long-term laboratory study.
Allometric scaling; Body-mass values; Cocoon fertility; Eisenia; Failure rates; Gompertz