Ageing, genes, environment and epigenetics: what twin studies tell us now, and in the future

Dietary Patterns, Skeletal Muscle Health, and Sarcopenia in Older Adults

In recent decades, the significance of diet and dietary patterns (DPs) for skeletal muscle health has been gaining attention in ageing and nutritional research. Sarcopenia, a muscle disease characterised by low muscle strength, mass, and function is associated with an increased risk of functional decline, frailty, hospitalization, and death. The prevalence of sarcopenia increases with age and leads to high personal, social, and economic costs. Finding adequate nutritional measures to maintain muscle health, preserve function, and independence for the growing population of older adults would have important scientific and societal implications. Two main approaches have been employed to study the role of diet/DPs as a modifiable lifestyle factor in sarcopenia. An a priori or hypothesis-driven approach examines the adherence to pre-defined dietary indices such as the Mediterranean diet (MED) and Healthy Eating Index (HEI)—measures of diet quality—in relation to muscle health outcomes. A posteriori or data-driven approaches have used statistical tools—dimension reduction methods or clustering—to study DP-muscle health relationships. Both approaches recognise the importance of the whole diet and potential cumulative, synergistic, and antagonistic effects of foods and nutrients on ageing muscle. In this review, we have aimed to (i) summarise nutritional epidemiology evidence from four recent systematic reviews with updates from new primary studies about the role of DPs in muscle health, sarcopenia, and its components; (ii) hypothesise about the potential mechanisms of ‘myoprotective’ diets, with the MED as an example, and (iii) discuss the challenges facing nutritional epidemiology to produce the higher level evidence needed to understand the relationships between whole diets and healthy muscle ageing.

Primers on nutrigenetics and nutri(epi)genomics: Origins and development of precision nutrition

Understanding the relationship between genotype and phenotype is a central goal not just for genetics but also for medicine and biological sciences. Despite outstanding technological progresses, genetics alone is not able to completely explain phenotypes, in particular for complex diseases. Given the existence of a "missing heritability", growing attention has been given to non-mendelian mechanisms of inheritance and to the role of the environment. The study of interaction between gene and environment represents a challenging but also a promising field with high potential for health prevention, and epigenetics has been suggested as one of the best candidate to mediate environmental effects on the genome. Among environmental factors able to interact with both genome and epigenome, nutrition is one of the most impacting. Not just our genome influences the responsiveness to food and nutrients, but vice versa, nutrition can also modify gene expression through epigenetic mechanisms. In this complex picture, nutrigenetics and nutrigenomics represent appealing disciplines aimed to define new prospectives of personalized nutrition. This review introduces to the study of gene-environment interactions and describes how nutrigenetics and nutrigenomics modulate health, promoting or affecting healthiness through life-style, thus playing a pivotal role in modulating the effect of genetic predispositions.

Noncommunicable disease risk factors among older adults aged 60-69 years in Nepal: findings from the STEPS survey 2013

Both the noncommunicable diseases (NCDs) burden and the population of older adults are increasing in Nepal. This study aims to estimate the prevalence of behavioral and biological risk factors of common NCDs among Nepali older adults aged 60-69 years. A subsample analysis of data from the 2013 Nepal STEPwise approach to Surveillance (STEPS) survey was conducted with 526 older adults aged 60-69 years. STEPS sample weighting and domain analyses were used to include the entire sample for variance estimation and to obtain prevalence estimates and corresponding 95% confidence intervals (CI) for our selected population of older adults. All participants had at least one risk factor for NCDs; about one-fourth had four. Of the eight examined risk factors, inadequate fruit/vegetable intake (98.6%, 95% CI: 96.9-100.0), hypertension (57.2%, 95% CI: 51.0-63.4), and hypercholesterolemia (37.9%, 95% CI: 30.8-44.9) were ranked the three most prevalent risk factors while physical inactivity (2.5%, 95% CI: 1.0-4.0) was least prevalent. Prevalence of smoking was 31% (95% CI: 24.9-37.2), overweight/obesity was 19% (95% CI: 13.1-25.2), alcohol use was 18% (95% CI: 12.2-23.5), diabetes was 15% (95% CI: 8.5-21.4), and 36% (95% CI: 30.9-42.0) of the older participants suffered discomfort due to oral health problems. Several risk factors, including current alcohol consumption, daily servings of fruit/vegetable intake, and overweight/obesity showed signficant variation in prevalence by gender, ethnicity, and place of residence, urban vs. rural. Epidemiological and demographic transitions are two emerging public health issues in Nepal. The baseline information provided by this study on the prevalence of NCD risk factors among Nepali older adults aged 60-69 years can inform policies and programs that focus on maximizing the health and well-being of older adults.

People with Dementia in Sub-Saharan Africa: From Support to Abuse by Caregivers: Results of EPIDEMCA-FU Program in Congo

BACKGROUND/AIMS

Dementia is an emerging public health problem in sub-Saharan Africa (SSA). In SSA, the stigma suffered by people with dementia (PWD) can be strongly linked to pejorative social representations, interfering in social relationships with informal caregivers. The objective of the study was to analyze the consequences of social representations of PWD in social interactions with informal caregivers.

METHODS

A qualitative study was conducted in Republic of Congo among 93 interviewees. Nondirectional interviews were conducted in local languages and complemented by participating observations. The collected data were transcribed literally, synthesized, and then coded to allow extraction and organization of text segments.

RESULTS

Informal caregivers, daughters-in-laws, were considered as abusers and granddaughters as benevolent. The leaders of syncretic churches and traditional healers were the first therapeutic itineraries of PWD, due to pejorative social representations of disease. Of these, some PWD have appeared at front of a customary jurisdiction for accusations of witchcraft. Dementia, perceived as a mysterious disease by informal caregivers, wasn't medicalized by leaders of syncretic churches, traditional healers, nurses, or general practitioners. Conclusion: Stigma, generated by social representations, can change the patient's behavior and the one of informal caregivers, leading to time delay in the search for appropriate help.

Major trauma and acceleration of the ageing process

It is well established that numerous factors can affect the rate at which we age biologically. Diet, physical activity, lifestyle and our genes all play a major role in influencing the ageing trajectory and longevity. Major trauma affects millions globally, is the major cause of death in young adults and could influence ageing processes but has largely been ignored by biogenterologists. The long-term health consequences of physical trauma are well known in the medical community, how trauma effects the ageing process at a molecular level is not. It has long been difficult to assess ageing trajectories due to the absence of a biomarker of biological rather than chronological age. Recent advances in epigenetics have helped by identifying specific DNA methylation sites as good indicators of biological age. Recent investigations into the impact of psychological trauma and the associated physical stress on accelerating ageing as measured by epigenetic drift are promising. The physical and metabolic stress which is synonymous with physical trauma may also accelerate the ageing process. We suggest that long term epigenetic profiling is required to understand to what degree the ageing trajectory is altered by trauma, which will in turn add support for the development of novel therapies to improve health outcomes for survivors of traumatic injury.

Impact of Growth Hormone-Related Mutations on Mammalian Aging

Mutations of a single gene can lead to a major increase in longevity in organisms ranging from yeast and worms to insects and mammals. Discovering these mutations (sometimes referred to as “longevity genes”) led to identification of evolutionarily conserved molecular, cellular, and organismal mechanisms of aging. Studies in mice provided evidence for the important role of growth hormone (GH) signaling in mammalian aging. Mice with mutations or gene deletions leading to GH deficiency or GH resistance have reduced body size and delayed maturation, but are healthier and more resistant to stress, age slower, and live longer than their normal (wild type) siblings. Mutations of the same genes in people can provide remarkable protection from age-related disease, but have no consistent impact on lifespan. Ongoing research indicates that genetic defects in GH signaling are linked to extension of healthspan and lifespan via a variety of interlocking mechanism, including improvements in genome and stem cell maintenance, stress resistance, glucose homeostasis, and thermogenesis, along with reductions in the mechanistic target of rapamycin (mTOR) C1 complex signaling and in chronic low grade inflammation.

Cognitive function among older adults: ELSI-Brazil results

OBJECTIVE

To investigate macroregional variations in cognitive function in a national sample representative of the Brazilian population aged 50 years and older.

METHODS

Data from the baseline of the Longitudinal Study of Brazilian Elderly (ELSI-Brazil), collected between 2015 and 2016, were used. Memory was measured by means of a 10-word list and executive function, by semantic verbal fluency, based on the naming of animals. Gender, age, education, and rural or urban residence were potentially confounding.

RESULTS

Among the 9,412 ELSI-Brazil participants, 9,085 were included in the analysis; 53.9% were women and the average age was 63.0 (0.42) years. After adjusting for potential confounding variables, average scores for memory and verbal fluency were lower in the Northeast region and higher in the Midwest and Southeast, respectively. In the South region, higher scores were found for immediate and combined memory. In all regions, older participants and those with lower schooling had worse scores for memory and verbal fluency.

CONCLUSIONS

There are differences in cognitive function among older adults in the different macroregions, independent of age, gender, schooling, and rural or urban residence.

Leukocyte telomere length and epigenetic-based mortality risk score: associations with all-cause mortality among older adults

Telomere length (TL) has been established as a biomarker of aging and aging-related health outcomes, but showed only a weak or inconsistent association with all-cause mortality in previous epidemiological studies. Recently, an epigenetic 'mortality risk score' (MS) based on whole blood DNA methylation at 10 mortality-related CpG sites has been demonstrated to be strongly related to all-cause mortality at the population level. This study aimed to address the association between TL and this MS, and to assess and compare their associations with all-cause mortality. The MS was derived from the DNA methylation profiles measured by Illumina Human Methylation450K Beadchip and TL was measured by quantitative PCR at baseline among 1517 participants aged 50-75 of the German ESTHER cohort study. In cross-sectional bi- and multivariable analyses, the MS was strongly associated and showed monotonic dose-response relationships with TL (p-values <0.05). However, only the MS but not TL was associated with all-cause mortality during a median follow-up of 12.5 years. After controlling for potential covariates and TL, hazard ratios (95% CI) for all-cause mortality for low, moderate and high levels of the MS defined by 1, 2-5 and >5 CpG sites with aberrant methylation were 2.24 (1.13-4.41), 3.31 (1.76-6.22) and 6.33 (3.22-12.41) compared to a MS of 0, respectively. Our investigation shows that the epigenetic-based MS is strongly associated with TL, a broadly accepted aging biomarker, and at the same time shows much stronger associations with all-cause mortality than the latter.

Depression, malnutrition, and health-related quality of life among Nepali older patients

BACKGROUND

Little is known about the health, nutrition, and quality of life of the aging population in Nepal. Consequently, we aimed to assess the nutritional status, depression and health-related quality of life (HRQOL) of Nepali older patients and evaluate the associated factors. Furthermore, a secondary aim was to investigate the proposed mediation-moderation models between depression, nutrition, and HRQOL.

METHODS

A cross-sectional survey was conducted from January-April of 2017 among 289 Nepali older patients in an outpatient clinic at Nepal Medical College in Kathmandu. Nutritional status, depression and HRQOL were assessed using a mini nutritional assessment, geriatric depression scales, and the European quality of life tool, respectively. Linear regression models were used to find the factors associated with nutritional status, depression, and HRQOL. The potential mediating and moderating role of nutritional status on the relationship between depression and HRQOL was explored; likewise, for depression on the relationship between nutritional status and HRQOL.

RESULTS

The prevalence of malnutrition and depression was 10% and 57.4% respectively; depression-malnutrition comorbidity was 7%. After adjusting for age and gender, nutritional score (β = 2.87; BCa 95%CI = 2.12, 3.62) was positively associated and depression score (β = - 1.23; BCa 95%CI = - 1.72, - 0.72) was negatively associated with HRQOL. After controlling for covariates, nutritional status mediated 41% of the total effect of depression on HRQOL, while depression mediated 6.0% of the total effect of the nutrition on HRQOL.

CONCLUSIONS

A sizeable proportion of older patients had malnutrition and depression. Given that nutritional status had a significant direct (independently) and indirect (as a mediator) effect on HRQOL, we believe that nutritional screening and optimal nutrition among the older patients can make a significant contribution to the health and well-being of Nepali older patients. Nonetheless, these findings should be replicated in prospective studies before generalization.

Structure-function multi-scale connectomics reveals a major role of the fronto-striato-thalamic circuit in brain aging

Physiological aging affects brain structure and function impacting morphology, connectivity, and performance. However, whether some brain connectivity metrics might reflect the age of an individual is still unclear. Here, we collected brain images from healthy participants (N = 155) ranging from 10 to 80 years to build functional (resting state) and structural (tractography) connectivity matrices, both data sets combined to obtain different connectivity features. We then calculated the brain connectome age-an age estimator resulting from a multi-scale methodology applied to the structure-function connectome, and compared it to the chronological age (ChA). Our results were twofold. First, we found that aging widely affects the connectivity of multiple structures, such as anterior cingulate and medial prefrontal cortices, basal ganglia, thalamus, insula, cingulum, hippocampus, parahippocampus, occipital cortex, fusiform, precuneus, and temporal pole. Second, we found that the connectivity between basal ganglia and thalamus to frontal areas, also known as the fronto-striato-thalamic (FST) circuit, makes the major contribution to age estimation. In conclusion, our results highlight the key role played by the FST circuit in the process of healthy aging. Notably, the same methodology can be generally applied to identify the structural-functional connectivity patterns correlating to other biomarkers than ChA.

Cortical and hippocampal expression of inflammatory and intracellular signaling proteins in aged rats submitted to aerobic and resistance physical training

Aging is often accompanied by an increase in pro-inflammatory markers. This inflammatory process is directly related to cellular dysfunctions that induce events such as the exacerbated activation of cell death signaling pathways. In the aged brain, dysregulation of the normal activities of neuronal cells compromises brain functions, thereby favoring the onset of neurodegenerative diseases and cognitive deficits. Interactions between various stimuli, such as stress, are responsible for the modulation of cellular processes and activities. Physical exercise is a controllable model of stress, largely used as a strategy for studying the physiological mechanisms of inflammatory responses and their consequences. However, different types of physical exercise promote different responses in the organism. The present study was designed to investigate the expression of inflammatory cytokines and chemokines, and expression and activation of intracellular signaling proteins (CREB, ERK, Akt, p70S6k, STAT5, JNK, NFkB e p38) in the cerebral cortex and hippocampal formation of aged rats submitted to aerobic and resistance exercise. Inflammatory analysis showed that aged rats that underwent resistance training had decreased cortical levels of RANTES and a reduction in the hippocampal levels of MIP-2 when compared with control animals (sedentary). No significant difference was detected in the cortical and hippocampal inflammatory response between aerobic and sedentary groups. However, when comparing the two training models (aerobic vs resistance), it was observed that aerobic training increased the cortical levels of IL-13, IL-6, IL-17α compared with resistance training. Regarding the signaling proteins, a significant increase in cortical expression of the proteins JNK, ERK and p70S6k was found in the aerobic group in relation to the sedentary group. No significant change in the cortical and hippocampal expression of signaling proteins was detected between resistance training and sedentary groups. Nevertheless, when training models were compared, it was observed that aerobic training increased cortical expression of the total proteins p38, ERK, Akt and p70S6k in relation to resistance training. Taken together, these results show that changes in the brain expression of inflammatory and cell survival proteins in aged rats depend on the type of physical training.

The effects of functional and traditional strength training on different strength parameters of elderly women: a randomized and controlled trial

BACKGROUND

Physical exercise is the main strategy for improving physical fitness in elderly population. However, it is not clear which training method lead to greater adaptations on maximal dynamic strength, muscle power, muscle endurance and isometric strength in this population. Thus, our aim was to compare the effects of functional and traditional training on these variables in the elderly.

METHODS

This study lasted twelve weeks, where 44 elderly women were randomly divided into three groups: functional training (FT; N.=18), traditional training (TT; N.=15), and control group (CG; N.=11). Maximal dynamic strength and muscle power tests were performed in pushing (Chest Press), pulling (Seated Row), and squatting (Leg Press 45°) actions. In addition, isometric strength with hand grip test (HG) and isometric dead lift test (ID) and muscle endurance with 30-s chair stand (CS) and 30-s arm curl (AC) tests were used.

RESULTS

Both experimental groups improved significantly in strength (FT: Chest Press 24.9%, Leg Press 45° 38.4%, Seated Row 21.6%; TT: Chest Press 27.6%, Leg Press 45° 40.9%, Seated Row 24.5%), power (FT: Chest Press 13.6%, Leg Press 45° 11.6%, Seated Row 13.6%; TT: Chest Press 18.2%, Leg Press 45° 9.8%, Seated Row 19.2%) isometric strength (FT: HG=14.7%, ID=13.6%; TT: HG=19.1%), and endurance (TF: CS=19.6%, AC=23.8%; TT: AC=15.5%) with P≤0.05, except TT in ID (4.4%) and SL (4.6%). There was no difference between experimental groups; however, both experimental groups were statistically superior to CG.

CONCLUSIONS

Both training protocols were equally effective in improving different strength manifestations in the elderly.

Aging in Place

Aging is a function of time and is a natural and integral part of the life cycle. Aging process differs among individuals and brings all kinds of changes, affecting not just the physical body and its functions, but also to the social, psychological and financial situations to individuals. Aging in place (AIP) is a common preference among older people for remaining in their local community and maintaining their social networks throughout the aging process. Issues about appropriateness of aging in place, long-term care, and residential homes are discussed. Some models and recommendations are discussed, completed with thoughts on future studies.

Factors Associated With Health-Related Quality of Life among Hypertensive Patients in Kathmandu, Nepal

Introduction

Nepal has a high prevalence of hypertension. While improving the overall health-related quality of life (HRQOL) is a central tenet to public health plans in developed nations, this focus has yet to be articulated in Nepal. Therefore, this study aims to identify the factors associated with HRQOL among hypertensive patients in Nepal.

Method

The EuroQol-5Dimension HRQOL survey was administered to 180 hypertensive patients, attending the outpatient clinic at Shahid Gangalal National Heart Center in Kathmandu, Nepal. Multiple linear regression models, adjusted for age and sex, were used to identify factors associated with HRQOL.

Results

The mean age and EuroQol visual analytic scale of the participants were 53.2 years and 63.7, respectively. Age [β = −0.56; 95% confidence interval (CI): −0.75 to −0.37], income (β = 0.02; 95% CI: 0.01, 0.03), family size (β = −0.98; 95% CI: −1.89, −0.07), number of antihypertensive drugs use (β = 4.62; 95% CI: 1.33, 7.90), and compliance to dietary salt advise (β = 4.86; 95% CI: 0.29, 9.43) were significant factors associated with HRQOL among participants. In addition, levels of education and self-perceived health were associated in a positive gradient to HRQOL. In mediation analysis, both, dietary low salt compliance and use of antihypertensive drugs, had a significant direct effect on HRQOL, and the use of antihypertensive drugs did not significantly mediate the relationship between dietary salt compliance and HRQOL.

Conclusion

Various factors were found to be associated with HRQOL among hypertensive patients in Kathmandu. Assessing HRQOL is a valuable technique to identify populations in need of services and interventions. This assessment can serve as a baseline, and in conjunction with multiple stakeholders, can guide public health policy, planning, and practices, especially those aimed toward improving the HRQOL of Nepalese with hypertension.

[Regulation of the expression of coenzyme Q-synthesis complex during ageing]

INTRODUCTION

Coenzyme Q is an essential component in the activity of the mitochondrial electron transport chain. Its synthesis involves, at least, a complex of ten different proteins. In this study, an attempt is made to determine the evolution of the expression of the genes involved in coenzyme Q synthesis during mouse ageing.

MATERIAL AND METHODS

The messenger RNA (mRNA) of different organs, such as brain, liver, kidney and skeletal muscle from young (8 months), mature (18 months), and old (24 months) mice was extracted by using Trizol and was then analysed by real time PCR (qPCR) using specific primers for all the known components of the coenzyme Q-synthesis complex (COQ genes).

RESULTS

Liver showed the highest age-dependent changes in mRNA levels of the different components of Q-synthesis complex, affecting the extent of the variation as well as the significance of the change. In most of the cases, mRNA levels of the different components were higher in mature animals compared to young and old animals. When mRNAs of young and old animals were compared, only minor reductions of mRNA levels were found. Kidney showed a pattern similar to that found in liver as regards the changes in expression, although with lower increases in mature animals than those observed in the liver. Brain and skeletal muscle showed low variations, with muscle being the tissue with less changes, although a pattern similar to that found in liver and kidney was found, with slight increases in mature animals.

DISCUSSION

The results of this study indicate that ageing is an important factor affecting COQ gene expression, but its effect depends on the organ, and that mature animals show higher levels of mRNA than young and old animals. Taken into consideration the importance of coenzyme Q in cell metabolism and ageing, a more detailed study is needed to understand the gene regulation of the coenzyme Q-synthesis mechanisms during ageing.

Defining Health Trajectories in Older Adults With Five Clinical Indicators

Background:

People age differently, challenging the identification of those more at risk of rapid health deterioration. This study aimed to explore the heterogeneity in the health of older adults by using five clinical indicators to detect age-related variation and individual health trajectories over time.

Methods:

Health of 3,363 people aged 60+ from the Swedish National study on Aging and Care-Kungsholmen (SNAC-K) assessed at baseline and at 3- and 6-year follow-ups. Number of chronic diseases, physical and cognitive performance, personal and instrumental activities of daily living were integrated in a health assessment tool (HAT). Interindividual health differences at baseline and follow-ups were assessed with logistic quantile regression. Intraindividual health trajectories were traced with quantile mixed-effect models.

Results:

The HAT score ranges from 0 (poor health) to 10 (good health); each score corresponds to a specific clinical profile. HAT was reliable over time and accurately predicted adverse health outcomes (receiver-operating characteristic areas: hospitalization = 0.78; 95% confidence interval = 0.74–0.81; mortality = 0.85; 95% confidence interval = 0.83–0.87; similar areas obtained for gait speed). Before age 85, at least 90% of participants were free of severe disability, and at least 50% were functionally independent despite chronic disorders. Age- and sex-related variation and high heterogeneity in health were detected at baseline and confirmed by intraindividual health trajectories.

Conclusions:

This study provides a positive picture of the health status of people 60+. Despite the complexity and heterogeneity of health in this age group, we could identify age- and sex-specific health trajectories using an integrated HAT. HAT is potentially useful in clinical practice and public health interventions.

The Isfahan Comprehensive Elderly Study: Objectives, research design, methodology, and preliminary results

BACKGROUND

This paper presents the objectives, research design, methodology, and primary findings of the Isfahan Comprehensive Elderly Study (ICES).

MATERIALS AND METHODS

In this cross-sectional study, 603 elderly persons (aged 60 and over) were selected by multistage cluster sampling method from Isfahan, Iran, in 2016 comprehensive questionnaires along with a detailed interview were used to collect information on personal, family, socioeconomic, health and social services characteristics, life styles, physical illnesses and chronic diseases, mental, emotional and cognition disorders, quality of life, disabilities, sleep quality, social supports, life satisfaction, self-efficacy, and of participants.

RESULTS

The mean ± standard deviation (SD) age of participants was 69.66 ± 6.31 years, consisting of 50.75% females. About 23% of elderly persons were at the risk of malnutrition and 4.5% were current smoker. Severe and mild depression were documented in 9.3% and 30.2% among included study subjects, respectively. About half of the participants had hypertension, and 26.8% suffered from cardiovascular disease. The mean ± SD of total score of Geriatric Depression Scale, Perceived Stress Scale, Older People's Quality of Life, Physical Activity Scale for the Elderly and Pittsburg Sleep Quality Index was 8.84 ± 6.79, 14.76 ± 5.92, 133.99 ± 10.55, 142.04 ± 120.53, and 6.17 ± 3.44, respectively. Elderly males had significantly higher life satisfaction and self-efficacy and better cognitive function than females (P < 0.01).

CONCLUSION

The findings of current study provided a comprehensive overview of the current health status and lifestyle of older adults in Isfahan city. The ICES could help policy makers to design appropriate prevention and interventional programs and policies to cover the specific needs of the elderly population.

The forkhead-like transcription factor (Fhl1p) maintains yeast replicative lifespan by regulating ribonucleotide reductase 1 (RNR1) gene transcription

In eukaryotes, numerous genetic factors contribute to the lifespan including metabolic enzymes, signal transducers, and transcription factors. As previously reported, the forkhead-like transcription factor (FHL1) gene was required for yeast replicative lifespan and cell proliferation. To determine how Fhl1p regulates the lifespan, we performed a DNA microarray analysis of a heterozygous diploid strain deleted for FHL1. We discovered numerous Fhl1p-target genes, which were then screened for lifespan-regulating activity. We identified the ribonucleotide reductase (RNR) 1 gene (RNR1) as a regulator of replicative lifespan. RNR1 encodes a large subunit of the RNR complex, which consists of two large (Rnr1p/Rnr3p) and two small (Rnr2p/Rnr4p) subunits. Heterozygous deletion of FHL1 reduced transcription of RNR1 and RNR3, but not RNR2 and RNR4. Chromatin immunoprecipitation showed that Fhl1p binds to the promoter regions of RNR1 and RNR3. Cells harboring an RNR1 deletion or an rnr1-C428A mutation, which abolishes RNR catalytic activity, exhibited a short lifespan. In contrast, cells with a deletion of the other RNR genes had a normal lifespan. Overexpression of RNR1, but not RNR3, restored the lifespan of the heterozygous FHL1 mutant to the wild-type (WT) level. The Δfhl1/FHL1 mutant conferred a decrease in dNTP levels and an increase in hydroxyurea (HU) sensitivity. These findings reveal that Fhl1p regulates RNR1 gene transcription to maintain dNTP levels, thus modulating longevity by protection against replication stress.

Genetic Influences on Functional Capacities in Aging

PURPOSE

Older populations are characterized by great heterogeneity in functional capacities and understanding the factors underlying these differences has been a major area of research for some decades. Genetic differences arguably play an important role in the heterogeneity observed for many outcomes among older individuals. However, the role of genes in the variation and trajectories of functional capacities in older age is poorly understood. This review was conducted to explore the evidence for genetic influences on physical functional capacities in aging.

DESIGN AND METHODS

This rapid review was conducted using the following criteria: journal articles retrieved from the PubMed, Embase, AgeLine, Scopus, and Web of Science electronic databases including the key words: genetics, genotype, polymorphism, physical or functional performance, functional capacity, activities of daily living, older, and elderly. In total, 118 articles were included for initial review.

RESULTS

The heritability of objective measures of physical function ranges from 30% to 60% in studies of older twins. There is a paucity of evidence about genetic influences on functional capacities, but some candidate genes related to functional capacity have been identified.

IMPLICATIONS

No strong candidate genes exist for functional capacities. Current methodologies are beginning to generate new evidence about genetic influences on overall physical function at older ages, but the variety of measures of functional capacity makes evidence difficult to compare.

Molecular Mechanisms of Arterial Stiffening

Stiffening of large arteries is a hallmark of vascular aging and one of the most important determinants of the age-related increase in blood pressure and cardiovascular disease events. Despite a substantial genetic component, the molecular mechanisms underlying phenotypic variability in arterial stiffness remain unknown. Previous genetic studies have identified several genetic variants that are associated with measures of arterial stiffness. Here, we review the relevant advances in the identification of pathways underlying arterial stiffness from genomic studies.

Beyond Calories: An Integrated Approach to Promote Health, Longevity, and Well-Being

In 1948, the World Health Organization defined health as 'a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity'. Detractors claim that this definition of health is utopian and unrealistic. However, accumulating evidence from experimental studies suggests that aging is not inevitably linked with the development of chronic diseases, and the age-associated accumulation of molecular damage can be prevented or greatly delayed by dietary and genetic manipulations that downregulate key cellular nutrient-sensing pathways. Nonetheless, to obtain a state of complete physical, mental, and social well-being, we as human beings need to go beyond nutrition or pharmacological treatments and implement a combination of interventions that enhance not only our metabolic health but also our psychological, emotional, intellectual and spiritual development, our social relationships and cultural well-being. This perspective highlights a range of scientific research-based interventions that can potentially be used to promote human health and longevity. We will also briefly address the importance of environmental health in achieving this goal.

Aging Trajectories in Different Body Systems Share Common Environmental Etiology: The Healthy Aging Twin Study (HATS)

Little is known about the extent to which aging trajectories of different body systems share common sources of variance. We here present a large twin study investigating the trajectories of change in five systems: cardiovascular, respiratory, skeletal, morphometric, and metabolic. Longitudinal clinical data were collected on 3,508 female twins in the TwinsUK registry (complete pairs:740 monozygotic (MZ), 986 dizygotic (DZ), mean age at entry 48.9 ± 10.4, range 18-75 years; mean follow-up 10.2 ± 2.8 years, range 4-17.8 years). Panel data on multiple age-related variables were used to estimate biological ages for each individual at each time point, in linear mixed effects models. A weighted average approach was used to combine variables within predefined body system groups. Aging trajectories for each system in each individual were then constructed using linear modeling. Multivariate structural equation modeling of these aging trajectories showed low genetic effects (heritability), ranging from 2% in metabolic aging to 22% in cardiovascular aging. However, we found a significant effect of shared environmental factors on the variations in aging trajectories in cardiovascular (54%), skeletal (34%), morphometric (53%), and metabolic systems (53%). The remainder was due to environmental factors unique to each individual plus error. Multivariate Cholesky decomposition showed that among aging trajectories for various body systems there were significant and substantial correlations between the unique environmental latent factors as well as shared environmental factors. However, there was no evidence for a single common factor for aging. This study, the first of its kind in aging, suggests that diverse organ systems share non-genetic sources of variance for aging trajectories. Confirmatory studies are needed using population-based twin cohorts and alternative methods of handling missing data.

Transcription factor genes essential for cell proliferation and replicative lifespan in budding yeast

Many of the lifespan-related genes have been identified in eukaryotes ranging from the yeast to human. However, there is limited information available on the longevity genes that are essential for cell proliferation. Here, we investigated whether the essential genes encoding DNA-binding transcription factors modulated the replicative lifespan of Saccharomyces cerevisiae. Heterozygous diploid knockout strains for FHL1, RAP1, REB1, and MCM1 genes showed significantly short lifespan. (1)H-nuclear magnetic resonance analysis indicated a characteristic metabolic profile in the Δfhl1/FHL1 mutant. These results strongly suggest that FHL1 regulates the transcription of lifespan related metabolic genes. Thus, heterozygous knockout strains could be the potential materials for discovering further novel lifespan genes.

Measuring pharmacogenetics in special groups: geriatrics

INTRODUCTION

The cytochrome P450 (CYP) enzymes oxidize about 80% of the most commonly used drugs. Older patients form a very interesting clinical group in which an increased prevalence of adverse drug reactions (ADRs) and therapeutic failures (TFs) is observed. Might CYP drug metabolism change with age, and justify the differences in drug response observed in a geriatric setting?

AREAS COVERED

A complete overview of the CYP pharmacogenetics with a focus on the epigenetic CYP gene regulation by DNA methylation in the context of advancing age, in which DNA methylation might change.

EXPERT OPINION

Responder phenotypes consist of a continuum spanning from ADRs to TFs, with the best responders at the midpoint. CYP genetics is the basis of this continuum on which environmental and physiological factors act, modeling the phenotype observed in clinical practice. Physiological age-related changes in DNA methylation, the main epigenetic mechanisms regulating gene expression in humans, results in a physiological decrease in CYP gene expression with advancing age. This may be one of the physiological changes that, together with increased drug use, contributed to the higher prevalence of ADRs and TFs observed in the geriatric setting, thus, making geriatrics a special group for pharmacogenetics.

Genetic Determinants of Epigenetic Patterns: Providing Insight into Disease

The field of epigenetics and our understanding of the mechanisms that regulate the establishment, maintenance and heritability of epigenetic patterns continue to grow at a remarkable rate. This information is providing increased understanding of the role of epigenetic changes in disease, insight into the underlying causes of these epigenetic changes and revealing new avenues for therapeutic intervention. Epigenetic modifiers are increasingly being pursued as therapeutic targets in a range of diseases, with a number of agents targeting epigenetic modifications already proving effective in diseases such as cancer. Although it is well established that DNA mutations and aberrant expression of epigenetic modifiers play a key role in disease, attention is now turning to the interplay between genetic and epigenetic factors in complex disease etiology. The role of genetic variability in determining epigenetic profiles, which can then be modified by environmental and stochastic factors, is becoming more apparent. Understanding the interplay between genetic and epigenetic factors is likely to aid in identifying individuals most likely to benefit from epigenetic therapies. This goal is coming closer to realization because of continual advances in laboratory and statistical tools enabling improvements in the integration of genomic, epigenomic and phenotypic data.

Cytochrome P450 and ischemic heart disease: current concepts and future directions

INTRODUCTION

The P450 enzymes (P450s) mediate the biotransformation of several drugs, steroid hormones, eicosanoids, cholesterol, vitamins, fatty acids and bile acids, many of which affect cardiovascular homeostasis. Experimental studies have demonstrated that several P450s modulate important steps in the pathogenesis of ischemic heart disease (IHD).

AREAS COVERED

This article discusses the current knowledge on i) the expression of P450s in cardiovascular and renal tissues; ii) the role of P450s in the pathophysiology of IHD, in particular the modulation of blood pressure and cardiac hypertrophy, coronary arterial tone, ischemia-reperfusion injury and the metabolism of cardiovascular drugs; iii) the available evidence from observational studies on the association between P450 gene polymorphisms and risk of myocardial infarction (MI); and iv) suggestions for further research in this area.

EXPERT OPINION

P450s exert important modulatory effects in experimental models of IHD and MI. However, observational studies have provided conflicting results on the association between P450 genetic polymorphisms and MI. Further, adequately powered studies are required to ascertain the biological and clinical impact of P450s on clinical IHD end-points, that is, fatal and nonfatal MI, revascularization and long-term outcomes post MI. Pharmacogenetic substudies of recently completed cardiovascular clinical trials might represent an alternative strategy in this context.

Epigenomics and the regulation of aging

It is tempting to assume that a gradual accumulation of damage 'causes' an organism to age, but other biological processes present during the lifespan, whether 'programmed' or 'hijacked', could control the type and speed of aging. Theories of aging have classically focused on changes at the genomic level; however, individuals with similar genetic backgrounds can age very differently. Epigenetic modifications include DNA methylation, histone modifications and ncRNA. Environmental cues may be 'remembered' during lifespan through changes to the epigenome that affect the rate of aging. Changes to the epigenomic landscape are now known to associate with aging, but so far causal links to longevity are only beginning to be revealed. Nevertheless, it is becoming apparent that there is significant reciprocal regulation occurring between the epigenomic levels. Future work utilizing new technologies and techniques should build a clearer picture of the link between epigenomic changes and aging.

Cognitive change in older women using a computerised battery: a longitudinal quantitative genetic twin study

Cognitive performance is known to change over age 45, especially processing speed. Studies to date indicate that change in performance with ageing is largely environmentally mediated, with little contribution from genetics. We estimated the heritability of a longitudinal battery of computerised cognitive tests including speed measures, using a classical twin design. 324 (127 MZ, 197 DZ) female twins, aged 43–73 at baseline testing, were followed-up after 10 years, using seven measures of the Cambridge Automated Neuropsychological Test battery, four of which were measures of response latency (speed). Results were analysed using univariate and bivariate structural equation modelling. Heritability of longitudinal change was found in 5 of the 7 tests, ranging from 21 to 41 %. The genetic aetiology was remarkably stable. The first principle component of change was strongly associated with age (p < 0.001) and heritable at 47 % (27–62 %). While estimates for heritability increased in all measures over time compared to baseline, these increases were statistically non-significant. This computerised battery showed significant heritability of age-related change in cognition. Focus on this form of change may aid the search for genetic pathways involved in normal and pre-morbid cognitive ageing.

Epigenetic influences in the aetiology of cancers arising from breast and prostate: a hypothesised transgenerational evolution in chromatin accessibility

Epidemiological studies have consistently supported the notion that environmental and/or dietary factors play a central role in the aetiology of cancers of the breast and prostate. However, for more than five decades investigators have failed to identify a single cause-and-effect factor, which could be implicated; identification of a causative entity would allow the implementation of an intervention strategy in at-risk populations. This suggests a more complex pathoaetiology for these cancer sites, compared to others. When one examines the increases or decreases in incidence of specific cancers amongst migrant populations, it is notable that disease arising in colon or stomach requires one or at most two generations to exhibit a change in incidence to match that of high-incidence regions, whereas for breast or prostate cancer, at least three generations are required. This generational threshold could suggest a requirement for nonmutation-driven epigenetic alterations in the F0/F1 generations (parental/offspring adopting a more westernized lifestyle), which then predisposes the inherited genome of subsequent generations to mutagenic/genotoxic alterations leading to the development of sporadic cancer in these target sites. As such, individual susceptibility to carcinogen insult would not be based per se on polymorphisms in activating/detoxifying/repair enzymes, but on elevated accessibility of crucial target genes (e.g., oncogenes, tumour suppressor genes) or hotspots therein to mutation events. This could be termed a genomic susceptibility organizational structure (SOS). Several exposures including alcohol and heavy metals are epigens (i.e., modifiers of the epigenome), whereas others are mutagenic/genotoxic, for example, heterocyclic aromatic amines; humans are continuously and variously exposed to mixtures of these agents. Within such a transgenerational multistage model of cancer development, determining the interaction between epigenetic modification to generate a genomic SOS and genotoxic insult will facilitate a new level of understanding in the aetiology of cancer.

Neuronal responses to physiological stress

Physiological stress can be defined as any external or internal condition that challenges the homeostasis of a cell or an organism. It can be divided into three different aspects: environmental stress, intrinsic developmental stress, and aging. Throughout life all living organisms are challenged by changes in the environment. Fluctuations in oxygen levels, temperature, and redox state for example, trigger molecular events that enable an organism to adapt, survive, and reproduce. In addition to external stressors, organisms experience stress associated with morphogenesis and changes in inner chemistry during normal development. For example, conditions such as intrinsic hypoxia and oxidative stress, due to an increase in tissue mass, have to be confronted by developing embryos in order to complete their development. Finally, organisms face the challenge of stochastic accumulation of molecular damage during aging that results in decline and eventual death. Studies have shown that the nervous system plays a pivotal role in responding to stress. Neurons not only receive and process information from the environment but also actively respond to various stresses to promote survival. These responses include changes in the expression of molecules such as transcription factors and microRNAs that regulate stress resistance and adaptation. Moreover, both intrinsic and extrinsic stresses have a tremendous impact on neuronal development and maintenance with implications in many diseases. Here, we review the responses of neurons to various physiological stressors at the molecular and cellular level.