The impact of age-related dysregulation of the angiotensin system on mitochondrial redox balance

Aging is associated with the accumulation of various deleterious changes in cells. According to the free radical and mitochondrial theory of aging, mitochondria initiate most of the deleterious changes in aging and govern life span. The failure of mitochondrial reduction-oxidation (redox) homeostasis and the formation of excessive free radicals are tightly linked to dysregulation in the Renin Angiotensin System (RAS). A main rate-controlling step in RAS is renin, an enzyme that hydrolyzes angiotensinogen to generate angiotensin I. Angiotensin I is further converted to Angiotensin II (Ang II) by angiotensin-converting enzyme (ACE). Ang II binds with equal affinity to two main angiotensin receptors—type 1 (AT₁R) and type 2 (AT₂R). The binding of Ang II to AT₁R activates NADPH oxidase, which leads to increased generation of cytoplasmic reactive oxygen species (ROS). This Ang II-AT₁R–NADPH-ROS signal triggers the opening of mitochondrial K_ATP channels and mitochondrial ROS production in a positive feedback loop. Furthermore, RAS has been implicated in the decrease of many of ROS scavenging enzymes, thereby leading to detrimental levels of free radicals in the cell. AT₂R is less understood, but evidence supports an anti-oxidative and mitochondria-protective function for AT₂R. The overlap between age related changes in RAS and mitochondria, and the consequences of this overlap on age-related diseases are quite complex. RAS dysregulation has been implicated in many pathological conditions due to its contribution to mitochondrial dysfunction. Decreased age-related, renal and cardiac mitochondrial dysfunction was seen in patients treated with angiotensin receptor blockers. The aim of this review is to: (a) report the most recent information elucidating the role of RAS in mitochondrial redox hemostasis and (b) discuss the effect of age-related activation of RAS on generation of free radicals.

Multiple myeloma in the very old: an IASIA conference report

Multiple myeloma (MM) in patients aged greater than 80 years poses an increasingly common challenge for oncology providers. A multidisciplinary workshop was held in which MM-focused hematologists/oncologists, geriatricians, and associated health-care team members discussed the state of research for MM therapy, as well as themes from geriatric medicine that pertain directly to this patient population. A summary statement of our discussions is presented here, in which we highlight several topics. MM disproportionately affects senior adults, and demographic trends indicate that this trend will accelerate. Complex issues impact cancer in seniors, and although factors such as social environment, comorbidities, and frailty have been well characterized in nononcological geriatric medicine, these themes have been inadequately explored in cancers such as MM, despite their clear relevance to this field. Therapeutically, novel agents have improved survival for MM patients of all ages, but less so for seniors than younger patients for a variety of reasons. Lastly, both MM- and treatment-related symptoms and toxicities require special attention in senior adults. Existing research provides limited insight into how best to manage these often complex patients, who are often not reflected in typical clinical trial populations. We hence offer suggestions for clinical trials that address knowledge gaps in how to manage very old and/or frail patients with MM, given the complicated issues that often surround this patient population.

Skeletal muscle ATP kinetics are impaired in frail mice

The interleukin-10 knockout mouse (IL10(tm/tm)) has been proposed as a model for human frailty, a geriatric syndrome characterized by skeletal muscle (SM) weakness, because it develops an age-related decline in SM strength compared to control (C57BL/6J) mice. Compromised energy metabolism and energy deprivation appear to play a central role in muscle weakness in metabolic myopathies and muscular dystrophies. Nonetheless, it is not known whether SM energy metabolism is altered in frailty. A combination of in vivo (31)P nuclear magnetic resonance experiments and biochemical assays was used to measure high-energy phosphate concentrations, the rate of ATP synthesis via creatine kinase (CK), the primary energy reserve reaction in SM, as well as the unidirectional rates of ATP synthesis from inorganic phosphate (Pi) in hind limb SM of 92-week-old control (n = 7) and IL10(tm/tm) (n = 6) mice. SM Phosphocreatine (20.2 ± 2.3 vs. 16.8 ± 2.3 μmol/g, control vs. IL10(tm/tm), p < 0.05), ATP flux via CK (5.0 ± 0.9 vs. 3.1 ± 1.1 μmol/g/s, p < 0.01), ATP synthesis from inorganic phosphate (Pi → ATP) (0.58 ± 0.3 vs. 0.26 ± 0.2 μmol/g/s, p < 0.05) and the free energy released from ATP hydrolysis (∆G ∼ATP) were significantly lower and [Pi] (2.8 ± 1.0 vs. 5.3 ± 2.0 μmol/g, control vs. IL10(tm/tm), p < 0.05) markedly higher in IL10(tm/tm) than in control mice. These observations demonstrate that, despite normal in vitro metabolic enzyme activities, in vivo SM ATP kinetics, high-energy phosphate levels and energy release from ATP hydrolysis are reduced and inorganic phosphate is elevated in a murine model of frailty. These observations do not prove, but are consistent with the premise, that energetic abnormalities may contribute metabolically to SM weakness in this geriatric syndrome.

Frailty consensus: a call to action

Frailty is a clinical state in which there is an increase in an individual's vulnerability for developing increased dependency and/or mortality when exposed to a stressor. Frailty can occur as the result of a range of diseases and medical conditions. A consensus group consisting of delegates from 6 major international, European, and US societies created 4 major consensus points on a specific form of frailty: physical frailty. 1. Physical frailty is an important medical syndrome. The group defined physical frailty as "a medical syndrome with multiple causes and contributors that is characterized by diminished strength, endurance, and reduced physiologic function that increases an individual's vulnerability for developing increased dependency and/or death." 2. Physical frailty can potentially be prevented or treated with specific modalities, such as exercise, protein-calorie supplementation, vitamin D, and reduction of polypharmacy. 3. Simple, rapid screening tests have been developed and validated, such as the simple FRAIL scale, to allow physicians to objectively recognize frail persons. 4. For the purposes of optimally managing individuals with physical frailty, all persons older than 70 years and all individuals with significant weight loss (>5%) due to chronic disease should be screened for frailty.

Frailty and early hospital readmission after kidney transplantation

Early hospital readmission (EHR) after kidney transplantation (KT) is associated with increased morbidity and higher costs. Registry-based recipient, transplant and center-level predictors of EHR are limited, and novel predictors are needed. We hypothesized that frailty, a measure of physiologic reserve initially described and validated in geriatrics and recently associated with early KT outcomes, might serve as a novel, independent predictor of EHR in KT recipients of all ages. We measured frailty in 383 KT recipients at Johns Hopkins Hospital. EHR was ascertained from medical records as ≥1 hospitalization within 30 days of initial post-KT discharge. Frail KT recipients were much more likely to experience EHR (45.8% vs. 28.0%, p = 0.005), regardless of age. After adjusting for previously described registry-based risk factors, frailty independently predicted 61% higher risk of EHR (adjusted RR = 1.61, 95% CI: 1.18-2.19, p = 0.002). In addition, frailty improved EHR risk prediction by improving the area under the receiver operating characteristic curve (p = 0.01) as well as the net reclassification index (p = 0.04). Identifying frail KT recipients for targeted outpatient monitoring and intervention may reduce EHR rates.

Simple biologically informed inflammatory index of two serum cytokines predicts 10 year all-cause mortality in older adults

BACKGROUND

Individual measurements of inflammation have been utilized to assess adverse outcomes risk in older adults with varying degrees of success. This study was designed to identify biologically informed, aggregate measures of inflammation for optimal risk assessment and to inform further biological study of inflammatory pathways.

METHODS

In total, 15 nuclear factor-kappa B-mediated pathway markers of inflammation were first measured in baseline serum samples of 1,155 older participants in the InCHIANTI population. Of these, C-reactive protein, interleukin-1-receptor antagonist, interleukin-6, interleukin-18, and soluble tumor necrosis factor-α receptor-1 were independent predictors of 5-year mortality. These five inflammatory markers were measured in baseline serum samples of 5,600 Cardiovascular Health Study participants. A weighted summary score, the first principal component summary score, and an inflammation index score were developed from these five log-transformed inflammatory markers, and their prediction of 10-year all-cause mortality was evaluated in Cardiovascular Health Study and then validated in InCHIANTI.

RESULTS

The inflammation index score that included interleukin-6 and soluble tumor necrosis factor-α receptor-1 was the best predictor of 10-year all-cause mortality in Cardiovascular Health Study, after adjusting for age, sex, education, race, smoking, and body mass index (hazards ratio = 1.62; 95% CI: 1.54, 1.70) compared with all other single and combined measures. The inflammation index score was also the best predictor of mortality in the InCHIANTI validation study (hazards ratio 1.33; 95% CI: 1.17-1.52). Stratification by sex and CVD status further strengthened the association of inflammation index score with mortality.

CONCLUSION

A simple additive index of serum interleukin-6 and soluble tumor necrosis factor-α receptor-1 best captures the effect of chronic inflammation on mortality in older adults among the 15 biomarkers measured.

Association between hearing loss and saccular dysfunction in older individuals

OBJECTIVE

1) Describe the association between hearing loss and dysfunction of each of the 5 vestibular end-organs--the horizontal, superior, and posterior semicircular canals; saccule; and utricle--in older individuals. 2) Evaluate whether hearing loss and vestibular end-organ deficits share any risk factors.

STUDY DESIGN

Cross-sectional study.

SETTING

Academic medical center.

PATIENTS

Fifty-one individuals age 70 years or older.

INTERVENTIONS

Audiometry, head-thrust dynamic visual acuity (htDVA), sound-evoked cervical vestibular-evoked myogenic potential (cVEMP), and tap-evoked ocular VEMP (oVEMP).

MAIN OUTCOME MEASURES

Audiometric pure-tone averages (PTA), htDVA LogMAR scores as a measure of semicircular canal function in each canal plane, and cVEMP and oVEMP amplitudes as a measure of saccular and utricular function, respectively.

RESULTS

We observed a significant correlation between hearing loss at high frequencies and reduced cVEMP amplitudes (or reduced saccular function; r = -0.37, p < 0.0001) in subjects age 70 years or older. In contrast, hearing loss was not associated with oVEMP amplitudes (or utricular function), or htDVA LogMAR scores (or semicircular canal function) in any of the canal planes. Age and noise exposure were significantly associated with measures of both cochlear and saccular dysfunction.

CONCLUSION

The concomitant decline in the cochlear and saccular function associated with aging may reflect their common embryologic origin in the pars inferior of the labyrinth. Noise exposure seems to be related to both saccular and cochlear dysfunction. These findings suggest a potential benefit of screening individuals with presbycusis-particularly those with significant noise exposure history-for saccular dysfunction, which may contribute to fall risk in the elderly.

Soluble CD14: genomewide association analysis and relationship to cardiovascular risk and mortality in older adults

OBJECTIVE

CD14 is a glycosylphosphotidylinositol-anchored membrane glycoprotein expressed on neutrophils and monocytes/macrophages that also circulates as a soluble form (sCD14). Despite the well-recognized role of CD14 in inflammation, relatively little is known about the genetic determinants of sCD14 or the relationship of sCD14 to vascular- and aging-related phenotypes.

METHODS AND RESULTS

We measured baseline levels of sCD14 in >5000 European-American and black adults aged 65 years and older from the Cardiovascular Health Study, who were well characterized at baseline for atherosclerotic risk factors and subclinical cardiovascular disease, and who have been followed for clinical cardiovascular disease and mortality outcomes up to 20 years. At baseline, sCD14 generally showed strong positive correlations with traditional cardio-metabolic risk factors and with subclinical measures of vascular disease such as carotid wall thickness and ankle-brachial index (independently of traditional cardiovascular disease risk factors), and was also inversely correlated with body mass index. In genomewide association analyses of sCD14, we (1) confirmed the importance of the CD14 locus on chromosome 5q21 in European-American; (2) identified a novel African ancestry-specific allele of CD14 associated with lower sCD14 in blacks; and (3) identified a putative novel association in European-American of a nonsynonymous variant of PIGC, which encodes an enzyme required for the first step in glycosylphosphotidylinositol anchor biosynthesis. Finally, we show that, like other acute phase inflammatory biomarkers, sCD14 predicts incident cardiovascular disease, and strongly and independently predicts all-cause mortality in older adults.

CONCLUSIONS

CD14 independently predicts risk mortality in older adults.

Abstract 276: Angiotensin AT1 Receptor Blockade Reverses Age-Related Changes in Myocardial Energy Metabolism and Increases Mitochondrial Biogenesis

Aging and mitochondrial function have been closely linked. We recently reported the identification of a mitochondrial angiotensin system. We hypothesized that angiotensin AT1 receptor blockade would increase energy production and mitochondrial biogenesis and reduce oxidative stress in aging hearts. We used Magnetic resonance spectroscopy to measure cardiac energy metabolism and function in young (20 wks old), aged (150 wks old) mice at baseline and after 4 weeks of losartan (50 mg/kg/day). For mitobiogenesis, qPCR was used to calculate CytB (mitochondrial gene)/GAPDH (nuclear gene) ratio and to measure mito-survival genes Sirt1, Sirt3, Nampt, and PGC-1α. Cardiomyocyte mitochondria from young, aged and treated mice were examined with electron microscopy. The expression of nitrotyrosine was quantified by immunohistochemistry. Older animals hearts (n=9) exhibited increase in LV mass (103±9 mg versus 120±8 mg, young (n=8) versus old (n=9), P<0.002). The mean cardiac PCr/ATP was reduced in older animals (1.5±0.2) than that of young mice (2.0±0.3, P<0.0004). Losartan abolished the LV mass increase in older animals (109±11 mg vs 101±7 mg, young versus old, P<0.1) and improved the impaired energy metabolism of the older hearts increasing the PCr/ATP ratios towards those observed in younger animals (1.94±0.01 vs 1.87±0.4, control versus old, P<0.7). Losartan increased EF in older animals (56±5% vs 63±5%, old versus old treated, P<0.01). Losartan increased mitobiogenesis in the hearts of treated young and old mice (3.8+2.5 folds, P<0.02 and 4.3+ 0.9 folds, P<0.0001). Mito-survival genes in the heart were not increased but PGC-1α was up-regulated by 2.8+1.6-fold, P<0.05 and 7+ 1.9-fold, P<0.001 in young and old treated mice. Electron micrograph analysis revealed that aging was associated with swollen cardiac mitochondria and disrupted cristae, which were reversed by Losartan. Losartan in older animals significantly reduced oxidative damage as evidenced by less Nitrotyrosine staining score in cardiomyocytes (2.5±0.5 vs. 1.3±0.4, old versus old treated, P<0.0009). Our results indicate that Losartan in aging increased mitobiogenesis, reduced oxidative stress, improved energy production and restored cardiac function to the healthy young adult level.

Hyperglycemia and incidence of frailty and lower extremity mobility limitations in older women

OBJECTIVES

To determine the degree to which hyperglycemia predicts the development of frailty and lower extremity mobility limitations.

DESIGN

Secondary data analysis of longitudinal data collected in a prospective cohort study.

SETTING

Baltimore, Maryland.

PARTICIPANTS

Three hundred twenty-nine women from the Women's Health and Aging Study II aged 70 to 79 at baseline who had all variables needed for analysis.

MEASUREMENTS

Glycosylated hemoglobin (HbA1c) at baseline, categorized as less than 5.5%, 5.5% to 5.9%, 6.0% to 6.4%, 6.5% to 7.9%, and 8.0% and greater, was the independent variable. The incidence of frailty and lower extremity mobility limitations (based on self-reported walking difficulty, walking speed, and Short Performance Physical Battery score) was determined (follow-up ≈ 9 years). Frailty was assessed using the Cardiovascular Health Study criteria. Covariates included demographic characteristics, body mass index, interleukin-6 level, and clinical history of comorbidities. Statistical analyses included Kaplan-Meier survival curves and Cox regression models adjusted for important covariates.

RESULTS

In time-to-event analyses, HbA1c category was associated with incidence of walking difficulty (P = .049) and low physical performance (P = .001); association with incidence of frailty and low walking speed had a trend toward significance (both P = .10). In regression models adjusted for demographic characteristics, HbA1c of 8.0% or greater (vs < 5.5%) was associated with an approximately three-times greater risk of incident frailty and three to five times greater risk of lower extremity mobility limitations (all P < .05). In fully adjusted models, HbA1c of 8.0% or greater (vs < 5.5%) was associated with incident frailty (hazard ratio (HR) = 3.33, 95% confidence interval (CI) = 1.24-8.93), walking difficulty (HR = 3.47, 95% CI = 1.26-9.55), low walking speed (HR = 2.82, 95% CI = 1.19-6.71), and low physical performance (HR = 3.60, 95% CI = 1.52-8.53).

CONCLUSION

Hyperglycemia is associated with the development of frailty and lower extremity mobility limitations in older women. Future studies should identify mediators of these relationships.

Inflammation and mortality in a frail mouse model

Mice homozygous for targeted deletion of the interleukin 10 gene (Il-10) have been partially characterized as a model for human frailty. These mice have increased serum interleukin (IL)-6 in midlife, skeletal muscle weakness, and an altered skeletal muscle gene expression profile compared to age and sex-matched C57BL/6 (B6) control mice. In order to further characterize for use as a frailty model, we evaluated the evolution of inflammatory pathway activation, endocrine change, and mortality in these mice. Serum was collected in groups of age- and sex-matched B6.129P2-Il10(tm1Cgn)/J (IL-10(tm/tm)) mice and B6 control mice at age 12, 24, 48, 72, and 90 weeks. Cytokines including IL-6, interleukin 1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), chemokine (C-X-C motif) ligand 1 (KC), IL-12, and IL-10 were measured using electro-chemiluminescent multiplex immunoassay and insulin-like growth factor 1 (IGF-1) was measured using solid-phase enzyme-linked immunosorbent assay. A separate longitudinal cohort was monitored from age 35 weeks to approximately 100 weeks. Survival was evaluated by Kaplan-Meier survival estimates and detailed necropsy information was gathered in a subset of mice that died or were sacrificed. In IL-10(tm/tm) mice compared to B6 controls, serum IL-6, IL-1β, TNF-α, IFN-γ, KC levels were significantly elevated across the age groups, serum mean IGF-1 levels were higher in the 48-week-old groups, and overall mortality rate was significantly higher. The quadratic relationship between IGF-1 and age was significantly different between the two strains of mice. Serum IL-6 was positively associated with IGF-1 but the effect was significantly larger in IL-10(tm/tm) mice. These findings provide additional rationale for the use of the IL-10(tm/tm) mouse as a model for frailty and for low-grade inflammatory pathway activation.

A genome-wide association study of aging

Human longevity and healthy aging show moderate heritability (20%-50%). We conducted a meta-analysis of genome-wide association studies from 9 studies from the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium for 2 outcomes: (1) all-cause mortality, and (2) survival free of major disease or death. No single nucleotide polymorphism (SNP) was a genome-wide significant predictor of either outcome (p < 5 × 10(-8)). We found 14 independent SNPs that predicted risk of death, and 8 SNPs that predicted event-free survival (p < 10(-5)). These SNPs are in or near genes that are highly expressed in the brain (HECW2, HIP1, BIN2, GRIA1), genes involved in neural development and function (KCNQ4, LMO4, GRIA1, NETO1) and autophagy (ATG4C), and genes that are associated with risk of various diseases including cancer and Alzheimer's disease. In addition to considerable overlap between the traits, pathway and network analysis corroborated these findings. These findings indicate that variation in genes involved in neurological processes may be an important factor in regulating aging free of major disease and achieving longevity.

Frailty is associated with impairment of vaccine-induced antibody response and increase in post-vaccination influenza infection in community-dwelling older adults

Annual immunization with a trivalent inactivated vaccine (TIV) is considered efficacious for prevention of seasonal influenza in older adults. However, significant controversy exists in the current literature regarding the clinical effectiveness of TIV immunization in this highly heterogeneous population. Frailty is an important geriatric syndrome characterized by decreased physiologic reserve and increased vulnerability to stressors. Using a validated set of frailty criteria, we conducted a prospective observational study to evaluate TIV-induced strain-specific hemagglutination inhibition (HI) antibody titers and post-vaccination rates of influenza-like illness (ILI) and infection in frail and nonfrail older adults. The results indicate that frailty was associated with significant impairment in TIV-induced strain-specific HI titers and increased rates of ILI and laboratory-confirmed influenza infection. These findings suggest that assessing frailty status in the elderly may identify those who are less likely to respond to TIV immunization and be at higher risk for seasonal influenza and its complications.

Exploring biologically relevant pathways in frailty

BACKGROUND

Frailty is a late-life syndrome of vulnerability to adverse health outcomes characterized by a phenotype that includes muscle weakness, fatigue, and inflammatory pathway activation. The identification of biologically relevant pathways that influence frailty is challenged by its biological complexity and the necessity in separating disease states from the syndrome of frailty. As with longevity research, genetic analyses may help to provide insights into biologically relevant pathways that contribute to frailty.

METHODS

Based on current understanding of the physiological basis of frailty, we hypothesize that variation in genes related to inflammation and muscle maintenance would associate with frailty. One thousand three hundred and fifty-four single-nucleotide polymorphisms were genotyped across 134 candidate genes using the Illumina Genotyping platform, and the rank order by strength of association between frailty and genotype was determined in a cross-sectional study.

RESULTS

Although no single-nucleotide polymorphism reached study-wide significance after controlling family-wise false-discovery rate at 0.05, single-nucleotide polymorphisms within the 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), Caspase 8 (CASP8), CREB-binding protein (CREBBP), lysine acetyltransferase 2B (KAT2B), and beta-transducin repeat containing (BTRC) loci were among those strongly associated with frailty.

CONCLUSIONS

The apoptosis- and transcription regulation-related pathways highlighted by this preliminary analysis were consistent with prior gene expression studies in a frail mouse model and provide useful etiological insights for future biological studies of frailty.

Critical transition in tissue homeostasis accompanies murine lung senescence

Background

Respiratory dysfunction is a major contributor to morbidity and mortality in aged populations. The susceptibility to pulmonary insults is attributed to “low pulmonary reserve”, ostensibly reflecting a combination of age-related musculoskeletal, immunologic and intrinsic pulmonary dysfunction.

Methods/Principal Findings

Using a murine model of the aging lung, senescent DBA/2 mice, we correlated a longitudinal survey of airspace size and injury measures with a transcriptome from the aging lung at 2, 4, 8, 12, 16 and 20 months of age. Morphometric analysis demonstrated a nonlinear pattern of airspace caliber enlargement with a critical transition occurring between 8 and 12 months of age marked by an initial increase in oxidative stress, cell death and elastase activation which is soon followed by inflammatory cell infiltration, immune complex deposition and the onset of airspace enlargement. The temporally correlative transcriptome showed exuberant induction of immunoglobulin genes coincident with airspace enlargement. Immunohistochemistry, ELISA analysis and flow cytometry demonstrated increased immunoglobulin deposition in the lung associated with a contemporaneous increase in activated B-cells expressing high levels of TLR4 (toll receptor 4) and CD86 and macrophages during midlife. These midlife changes culminate in progressive airspace enlargement during late life stages.

Conclusion/Significance

Our findings establish that a tissue-specific aging program is evident during a presenescent interval which involves early oxidative stress, cell death and elastase activation, followed by B lymphocyte and macrophage expansion/activation. This sequence heralds the progression to overt airspace enlargement in the aged lung. These signature events, during middle age, indicate that early stages of the aging immune system may have important correlates in the maintenance of tissue morphology. We further show that time-course analyses of aging models, when informed by structural surveys, can reveal nonintuitive signatures of organ-specific aging pathology.

Polymorphisms in the mitochondrial DNA control region and frailty in older adults

BACKGROUND

Mitochondria contribute to the dynamics of cellular metabolism, the production of reactive oxygen species, and apoptotic pathways. Consequently, mitochondrial function has been hypothesized to influence functional decline and vulnerability to disease in later life. Mitochondrial genetic variation may contribute to altered susceptibility to the frailty syndrome in older adults.

METHODOLOGY/PRINCIPAL FINDINGS

To assess potential mitochondrial genetic contributions to the likelihood of frailty, mitochondrial DNA (mtDNA) variation was compared in frail and non-frail older adults. Associations of selected SNPs with a muscle strength phenotype were also explored. Participants were selected from the Cardiovascular Health Study (CHS), a population-based observational study (1989-1990, 1992-1993). At baseline, frailty was identified as the presence of three or more of five indicators (weakness, slowness, shrinking, low physical activity, and exhaustion). mtDNA variation was assessed in a pilot study, including 315 individuals selected as extremes of the frailty phenotype, using an oligonucleotide sequencing microarray based on the Revised Cambridge Reference Sequence. Three mtDNA SNPs were statistically significantly associated with frailty across all pilot participants or in sex-stratified comparisons: mt146, mt204, and mt228. In addition to pilot participants, 4,459 additional men and women with frailty classifications, and an overlapping subset of 4,453 individuals with grip strength measurements, were included in the study population genotyped at mt204 and mt228. In the study population, the mt204 C allele was associated with greater likelihood of frailty (adjusted odds ratio = 2.04, 95% CI = 1.07-3.60, p = 0.020) and lower grip strength (adjusted coefficient = -2.04, 95% CI = -3.33- -0.74, p = 0.002).

CONCLUSIONS

This study supports a role for mitochondrial genetic variation in the frailty syndrome and later life muscle strength, demonstrating the importance of the mitochondrial genome in complex geriatric phenotypes.

A meta-analysis of four genome-wide association studies of survival to age 90 years or older: the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium

BACKGROUND

Genome-wide association studies (GWAS) may yield insights into longevity.

METHODS

We performed a meta-analysis of GWAS in Caucasians from four prospective cohort studies: the Age, Gene/Environment Susceptibility-Reykjavik Study, the Cardiovascular Health Study, the Framingham Heart Study, and the Rotterdam Study participating in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. Longevity was defined as survival to age 90 years or older (n = 1,836); the comparison group comprised cohort members who died between the ages of 55 and 80 years (n = 1,955). In a second discovery stage, additional genotyping was conducted in the Leiden Longevity Study cohort and the Danish 1905 cohort.

RESULTS

There were 273 single-nucleotide polymorphism (SNP) associations with p < .0001, but none reached the prespecified significance level of 5 x 10(-8). Of the most significant SNPs, 24 were independent signals, and 16 of these SNPs were successfully genotyped in the second discovery stage, with one association for rs9664222, reaching 6.77 x 10(-7) for the combined meta-analysis of CHARGE and the stage 2 cohorts. The SNP lies in a region near MINPP1 (chromosome 10), a well-conserved gene involved in regulation of cellular proliferation. The minor allele was associated with lower odds of survival past age 90 (odds ratio = 0.82). Associations of interest in a homologue of the longevity assurance gene (LASS3) and PAPPA2 were not strengthened in the second stage.

CONCLUSION

Survival studies of larger size or more extreme or specific phenotypes may support or refine these initial findings.

Common coding variants of the HNF1A gene are associated with multiple cardiovascular risk phenotypes in community-based samples of younger and older European-American adults: the Coronary Artery Risk Development in Young Adults Study and The Cardiovascular Health Study

BACKGROUND

The transcription factor hepatocyte nuclear factor (HNF)-1 alpha regulates the activity of a number of genes involved in innate immunity, blood coagulation, lipid and glucose transport and metabolism, and cellular detoxification. Common polymorphisms of the HNF-1 alpha gene (HNF1A) were recently associated with plasma C-reactive protein and gamma-glutamyl transferase concentration in middle-aged to older European Americans (EA).

METHODS AND RESULTS

We assessed whether common variants of HNF1A are associated with C-reactive protein, gamma-glutamyl transferase, and other atherosclerotic and metabolic risk factors, in the large, population-based Coronary Artery Risk Development in Young Adults Study of healthy young EA (n=2154) and African American (AA; n=2083) adults. The minor alleles of Ile27Leu (rs1169288) and Ser486Asn (rs2464196) were associated with 0.10 to 0.15 standard deviation units lower C-reactive protein and gamma-glutamyl transferase levels in EA. The same HNF1A coding variants were associated with higher low-density lipoprotein cholesterol, apolipoprotein B, creatinine, and fibrinogen in EA. We replicated the associations between HNF1A coding variants and C-reactive protein, fibrinogen, low-density lipoprotein cholesterol, and renal function in a second population-based sample of EA adults 65 years and older from the Cardiovascular Health Study. The HNF1A Ser486Asn and/or Ile27Leu variants were also associated with increased risk of subclinical coronary atherosclerosis in Coronary Artery Risk Development in Young Adults and with incident coronary heart disease in Cardiovascular Health Study. The Ile27Leu and Ser486Asn variants were 3-fold less common in AA than in EA. There was little evidence of association between HNF1A genotype and atherosclerosis-related phenotypes in AA.

CONCLUSIONS

Common polymorphisms of HNF1A seem to influence multiple phenotypes related to cardiovascular risk in the general population of younger and older EA adults.

Insulin resistance is associated with decreased quadriceps muscle strength in nondiabetic adults aged >or=70 years

OBJECTIVE

Lower-limb muscle strength is reduced in many people with diabetes. In this study, we examined whether quadriceps muscle strength is reduced in relation to insulin resistance in well-functioning ambulatory nondiabetic individuals.

RESEARCH DESIGN AND METHODS

Participants (age >or=70 years) underwent dual-energy X-ray absorptiometry (DEXA) scanning to ascertain muscle and fat mass, tests of quadriceps strength, computed tomography scanning of the quadriceps to gauge muscle lipid content, and fasting insulin and glucose level measurements from which homeostasis model assessment of insulin resistance (HOMA-IR) was derived.

RESULTS

In regression analysis, quadriceps strength per kilogram of muscle mass was negatively associated (P < 0.0001) with HOMA-IR independent of other factors negatively associated with strength such as increased age, female sex, low-physical activity, impaired fasting glucose, and increased total body fat. Muscle lipid content was not associated with strength.

CONCLUSIONS

A small decrease in quadriceps muscle force is associated with increased HOMA-IR in well-functioning nondiabetic adults, suggesting that diminished quadriceps muscle strength begins before diabetes.

Advanced glycation end products and their circulating receptors predict cardiovascular disease mortality in older community-dwelling women

AIMS

To characterize the relationship between advanced glycation end products (AGEs) and circulating receptors for AGEs (RAGE) with cardiovascular disease mortality.

METHODS

The relationships between serum AGEs, total RAGE (sRAGE), and endogenous secretory RAGE (esRAGE), and mortality were characterized in 559 community-dwelling women, double dagger 65 years, in Baltimore, Maryland.

RESULTS

During 4.5 years of follow-up, 123 (22%) women died, of whom 54 died with cardiovascular disease. The measure of serum AGEs was carboxymethyl-lysine (CML), a dominant AGE. Serum CML predicted cardiovascular disease mortality (Hazards Ratio [HR] for highest vs lower three quartiles, 1.94, 95% Confidence Interval [CI] 1.08-3.48, p=0.026), after adjusting for age, race, body mass index, and renal insufficiency. Serum sRAGE (ng/mL) and esRAGE (ng/mL) predicted cardiovascular disease mortality (HR per 1 Standard Deviation [SD] 1.27, 95% CI 0.98-1.65, p=0.07; HR 1.28, 95% CI 1.02-1.63, p=0.03), after adjusting for the same covariates. Among non-diabetic women, serum CML, sRAGE, and esRAGE, respectively, predicted cardiovascular disease mortality (HR for highest vs lower three quartiles, 2.29, 95% CI 1.21-4.34, p=0.01; HR per 1 SD, 1.24, 95% CI 0.92-1.65, p=0.16; HR per 1 SD 1.45, 95% CI 1.08-1.93, p=0.01), after adjusting for the same covariates.

CONCLUSIONS

High circulating AGEs and RAGE predict cardiovascular disease mortality among older community-dwelling women. AGEs are a potential target for interventions, as serum AGEs can be lowered by change in dietary pattern and pharmacological treatment.

Common variation in the beta-carotene 15,15'-monooxygenase 1 gene affects circulating levels of carotenoids: a genome-wide association study

Low plasma levels of carotenoids and tocopherols are associated with increased risk of chronic disease and disability. Because dietary intake of these lipid-soluble antioxidant vitamins is only poorly correlated with plasma levels, we hypothesized that circulating carotenoids (vitamin A-related compounds) and tocopherols (vitamin E-related compounds) are affected by common genetic variation. By conducting a genome-wide association study in a sample of Italians (n = 1190), we identified novel common variants associated with circulating carotenoid levels and known lipid variants associated with alpha-tocopherol levels. Effects were replicated in the Women's Health and Aging Study (n = 615) and in the alpha-Tocopherol, beta-Carotene Cancer Prevention (ATBC) study (n = 2136). In meta-analyses including all three studies, the G allele at rs6564851, near the beta-carotene 15,15'-monooxygenase 1 (BCMO1) gene, was associated with higher beta-carotene (p = 1.6 x 10(-24)) and alpha-carotene (p = 0.0001) levels and lower lycopene (0.003), zeaxanthin (p = 1.3 x 10(-5)), and lutein (p = 7.3 x 10(-15)) levels, with effect sizes ranging from 0.10-0.28 SDs per allele. Interestingly, this genetic variant had no significant effect on plasma retinol (p > 0.05). The SNP rs12272004, in linkage disequilibrium with the S19W variant in the APOA5 gene, was associated with alpha-tocopherol (meta-analysis p = 7.8 x 10(-10)) levels, and this association was substantially weaker when we adjusted for triglyceride levels (p = 0.002). Our findings might shed light on the controversial relationship between lipid-soluble anti-oxidant nutrients and human health.

Circulating oxidized low-density lipoproteins are associated with overweight, obesity, and low serum carotenoids in older community-dwelling women

OBJECTIVE

The objective of this study was to determine whether total serum carotenoids, alpha-tocopherol, selenium, and obesity were independently associated with oxidized low-density lipoproteins (ox-LDLs) in moderately to severely disabled older women living in the community.

METHODS

Serum ox-LDLs, carotenoids, alpha-tocopherol, and selenium were measured in a population-based sample of 543 moderately to severely disabled women > or = 65 y in the Women's Health and Aging Study I in Baltimore, Maryland.

RESULTS

Total serum carotenoids, smoking, overweight (body mass index 25-29.9 kg/m(2)), and obesity (body mass index > or = 30 mg/kg(2)) were significantly associated with the ox-LDL/LDL cholesterol ratio after adjusting for age, C-reactive protein, and chronic diseases. alpha-Tocopherol and selenium were not significantly associated with the ox-LDL/LDL cholesterol ratio.

CONCLUSION

Older women who are overweight or obese or who have low total serum carotenoids are more likely to have higher lipoprotein oxidation. Weight reduction in overweight/obese women and increased intake of carotenoid-rich foods may potentially reduce lipoprotein oxidation.

The physical and biological characterization of a frail mouse model

BACKGROUND

The development of animal models that approximate human frailty is necessary to facilitate etiologic and treatment-focused frailty research. The genetically altered IL-10(tm/tm) mouse does not express the antiinflammatory cytokine interleukin 10 (IL-10) and is, like frail humans, more susceptible to inflammatory pathway activation. We hypothesized that with increasing age, IL-10(tm/tm) mice would develop physical and biological characteristics similar to those of human frailty as compared to C57BL/6J control mice.

METHODS

Strength, activity, serum IL-6, and skeletal muscle gene expression were compared between age-matched and gender-matched IL-10(tm/tm) mice on C57BL/6J background and C57BL/6J control mice using a longitudinal design for physical characteristics and cross-sectional design for biological characteristics.

RESULTS

Strength levels declined significantly faster in IL-10(tm/tm) compared to control mice with increasing age. Serum IL-6 levels were significantly higher in older compared to younger IL-10(tm/tm) mice and were significantly higher in older IL-10(tm/tm) compared to age- and gender-matched C57BL/6J control mice. One hundred twenty-five genes, many related to mitochondrial biology and apoptosis, were differentially expressed in skeletal muscle between 50-week-old IL-10(tm/tm) and 50-week-old C57BL/6J mice. No expression differences between IL-10(tm/tm) age groups were identified by quantitative polymerase chain reaction.

CONCLUSION

These physical and biological findings suggest that the IL-10(tm/tm) mouse develops inflammation and strength decline consistent with human frailty at an earlier age compared to C57BL/6J control type mice. This finding provides rationale for the further development and utilization of the IL-10(tm/tm) mouse to study the biological basis of frailty.

Oxidative protein damage is associated with elevated serum interleukin-6 levels among older moderately to severely disabled women living in the community

BACKGROUND

Elevated interleukin (IL)-6 is associated with adverse outcomes. Our objective was to determine whether serum protein carbonyls, an indicator of oxidative protein damage and oxidative stress, were associated with IL-6.

METHODS

Serum protein carbonyls and IL-6 were measured in 739 women, age > or =65 years, in the Women's Health and Aging Study I.

RESULTS

Geometric mean of protein carbonyls was 0.082 nmol/mg. After adjusting for age and smoking status, log(e) serum protein carbonyls were associated with log(e) IL-6 (beta = 0.143, standard error [SE] = 0.048, p =.003) in linear regression analyses and with elevated IL-6 (> or =2.5 pg/mL) (odds ratio = 1.38, 95% confidence interval, 1.02-1.86, p =.037) in logistic regression analyses. CONCLUSION. Oxidative damage to proteins is independently associated with serum IL-6 among older women living in the community. Increased oxidative stress may be a factor involved in the pathogenesis of the proinflammatory state that occurs in older adults.

Oxidative stress and severe walking disability among older women

BACKGROUND

Oxidative stress has been implicated in sarcopenia and the loss of muscle strength with aging, but the relationship between oxidative stress and decrease in muscle strength and physical performance has not been well characterized. Serum protein carbonyls are markers of oxidative damage to proteins and are caused by oxidative stress.

METHODS

Serum protein carbonyls were measured at baseline and compared with a decrease in walking speed and development of severe walking disability (inability to walk or walking speed <0.4 m/sec) over 36 months of follow-up in 545 moderately to severely disabled women, aged > or =65 years, living in the community in Baltimore, Maryland (the Women's Health and Aging Study I).

RESULTS

After adjusting for age, body mass index, smoking, and chronic diseases, log(e) protein carbonyls (nmol/mg) were associated with a decrease in walking speed over 36 months (P=.002). During follow-up, 154 women (28.2%) developed severe walking disability. After adjusting for the same potential confounders, log(e) protein carbonyls were associated with incident severe walking disability (hazards ratio 1.42, 95% confidence interval, 1.02-1.98, P=.037).

CONCLUSION

High oxidative stress, as indicated by oxidative damage to proteins, is an independent predictor of decrease in walking speed and progression to severe walking disability among older women living in the community.

Oxidative stress is associated with greater mortality in older women living in the community

OBJECTIVES

To determine whether oxidative stress, as implied by oxidative damage to proteins, is associated with greater mortality in older women living in the community.

DESIGN

Longitudinal.

SETTING

Women's Health and Aging Study I, Baltimore, Maryland.

PARTICIPANTS

Seven hundred forty-six moderately to severely disabled women, aged 65 and older, with baseline measures of serum protein carbonyls.

MEASUREMENTS

Serum protein carbonyls, which consist of chemically stable aldehyde and ketone groups produced on protein side chains when they are oxidized, were measured using enzyme-linked immunosorbent assay. Multivariate logistic regression was used to adjust for potential confounders.

RESULTS

During 5 years of follow-up, 202 (27.1%) participants died. Geometric mean serum protein carbonyls were 0.091 nmol/mg in women who died and 0.083 nmol/mg in those who survived (P=.02). Log(e) protein carbonyls (nmol/mg) were associated with greater risk of mortality (hazards ratio=1.34, 95% confidence interval=1.01-1.79, P=.04) in a multivariate Cox proportional hazards model adjusting for age, current smoking, and body mass index.

CONCLUSION

Greater oxidative stress, as indicated by elevated serum protein carbonyl concentrations, was associated with greater risk of death in older women living in the community who were moderately to severely disabled. Prevention of oxidative stress may reduce the risk of mortality.

Common variants in the CRP gene in relation to longevity and cause-specific mortality in older adults: the Cardiovascular Health Study

Common polymorphisms in the CRP gene are associated with plasma CRP levels in population-based studies, but associations with age-related events are uncertain. A previous study of CRP haplotypes in older adults was broadened to include longevity and cause-specific mortality (all-cause, noncardiovascular (non-CV), and cardiovascular (CV)). Common haplotypes were inferred from four tagSNPs in 4512 whites and five tagSNPs in 812 blacks from the Cardiovascular Health Study, a longitudinal cohort of adults over age 65. Exploratory analyses addressed early versus late mortality. CRP haplotypes were not associated with all-cause mortality or longevity overall in either population, but associations with all-cause mortality differed during early and late periods. In blacks, the haplotype tagged by 3872A (rs1205) was associated with increased risk of non-CV mortality, relative to other haplotypes (adjusted hazard ratio for each additional copy: 1.42, 95% CI: 1.07, 1.87). Relative to other haplotypes, this haplotype was associated with decreased risk of early but not decreased risk of late CV mortality in blacks; among whites, a haplotype tagged by 2667C (rs1800947) gave similar but nonsignificant findings. If confirmed, CRP genetic variants may be weakly associated with CV and non-CV mortality in older adults, particularly in self-identified blacks.

Oxidative protein damage is associated with poor grip strength among older women living in the community

Grip strength, an indicator of muscle strength, has been shown to be a predictor of poor outcomes among older adults. Protein carbonylation, an indicator of oxidative damage to proteins, leads to cellular dysfunction and a decline in tissue function. Oxidative stress has been implicated in the pathogenesis of sarcopenia. The objective was to determine whether serum protein carbonyl concentrations are associated with grip strength in older women living in the community. A cross-sectional study was conducted in 672 women, aged 65 and older, from the Women's Health and Aging Study (WHAS) I, the one-third most disabled women residing in the community in Baltimore, MD. Protein carbonyl and grip strength were measured in each patient. In a multivariate analysis adjusting for age, race, body mass index, and Mini-Mental Status Examination score, protein carbonyls (nmol/mg) were associated with grip strength (beta = -6.77, P < 0.01). The statistical association was unchanged after the analysis adjusted for hypertension, congestive heart failure, and depression. Ordered logistic regression models adjusted for the above factors showed that protein carbonyls are associated with increased odds of being in the lower quartiles of grip strength (odds ratio 8.74, 95% confidence interval 1.06-71.89, P = 0.043). These results suggest oxidative protein damage is independently associated with low grip strength among older women living in the community. Increased oxidative stress may be contributing to loss of muscle strength in older adults.

Low serum selenium concentrations are associated with poor grip strength among older women living in the community

Aging is associated with a loss of muscle strength, and, in turn, loss of muscle strength has been associated with increased risk of frailty, disability and mortality. The factors that contribute to loss of muscle strength with aging have not been well characterized. Selenium is important in normal muscle function because of its role in selenoenzymes that protect muscle against oxidative damage. We hypothesized that low serum selenium concentrations were associated with poor grip strength. We examined the association between serum selenium and hand grip strength among 676 moderately to severely disabled community-dwelling women in the Women's Health and Aging Study I in Baltimore, Maryland. After adjusting for age, race, body mass index, Mini-Mental Status Examination score, current smoking, hypertension, congestive heart failure and depression, serum selenium was associated with grip strength (P=0.04). This study supports the idea that selenium is important to muscle strength in older women.

Leukocyte telomere length and cardiovascular disease in the cardiovascular health study

The telomere length of replicating somatic cells is inversely correlated with age and has been reported to be associated cross-sectionally with cardiovascular disease (CVD). Leukocyte telomere length, as expressed by mean terminal restriction fragment (TRF) length, was measured in 419 randomly selected participants from the Cardiovascular Health Study, comprising a community-dwelling cohort recruited in four US communities. The authors investigated associations between TRF length and selected measures of subclinical CVD/risk factors for CVD (data were collected at the 1992/1993 clinic visit) and incident CVD (ascertained through June 2002). In these participants (average age = 74.2 years (standard deviation, 5.2)), mean TRF length was 6.3 kilobase pairs (standard deviation, 0.62). Significant or borderline inverse associations were found between TRF length and diabetes, glucose, insulin, diastolic blood pressure, carotid intima-media thickness, and interleukin-6. Associations with body size and C-reactive protein were modified by gender and age, occurring only in men and in participants aged 73 years or younger. In younger (but not older) participants, each shortened kilobase pair of TRF corresponded with a threefold increased risk of myocardial infarction (hazard ratio = 3.08, 95% confidence interval: 1.22, 7.73) and stroke (hazard ratio = 3.22, 95% confidence interval: 1.29, 8.02). These results support the hypotheses that telomere attrition may be related to diseases of aging through mechanisms involving oxidative stress, inflammation, and progression to CVD.

Association of polymorphisms in the CRP gene with circulating C-reactive protein levels and cardiovascular events

CONTEXT

C-reactive protein (CRP) is an inflammation protein that may play a role in the pathogenesis of cardiovascular disease (CVD).

OBJECTIVE

To assess whether polymorphisms in the CRP gene are associated with plasma CRP, carotid intima-media thickness (CIMT), and CVD events.

DESIGN, SETTING, AND PARTICIPANTS

In the prospective, population-based Cardiovascular Health Study, 4 tag single-nucleotide polymorphisms (SNPs) (1919A/T, 2667G/C, 3872G/A, 5237A/G) were genotyped in 3941 white (European American) participants and 5 tag SNPs (addition of 790A/T) were genotyped in 700 black (African American) participants, aged 65 years or older, all of whom were without myocardial infarction (MI) or stroke before study entry. Median follow-up was 13 years (1989-2003).

MAIN OUTCOME MEASURES

Baseline CIMT; occurrence of MI, stroke, and CVD mortality during follow-up.

RESULTS

In white participants, 461 incident MIs, 491 incident strokes, and 490 CVD-related deaths occurred; in black participants, 67 incident MIs, 78 incident strokes, and 75 CVD-related deaths occurred. The 1919T and 790T alleles were associated with higher CRP levels in white and black participants, respectively. The 3872A allele was associated with lower CRP levels in both populations, and the 2667C allele was associated with lower CRP levels in white participants only. There was no association between CIMT and any CRP gene polymorphism in either population. In white participants, the 1919T allele was associated with increased risk of stroke for TT vs AA (hazard ratio [HR], 1.40; 95% confidence interval [CI], 1.06-1.87) and for CVD mortality (HR, 1.40; 95% CI, 1.10-1.90). In black participants, homozygosity for the 790T allele was associated with a 4-fold increased risk of MI compared with homozygosity for the 790A allele (95% CI, 1.58-10.53). The minor alleles of the 2 SNPs associated with lower plasma CRP concentration in white participants (2667C and 3872A) were associated with decreased risk of CVD mortality.

CONCLUSIONS

Genetic variation in the CRP gene is associated with plasma CRP levels and CVD risk in older adults.

Research Agenda for Frailty in Older Adults: Toward a Better Understanding of Physiology and Etiology: Summary from the American Geriatrics Society/National Institute on Aging Research Conference on Frailty in Older Adults

Evolving definitions of frailty, and improved understanding of molecular and physiological declines in multiple systems that may increase vulnerability in frail, older adults has encouraged investigators from many disciplines to contribute to this emerging field of research. This article reports on the results of the 2004 American Geriatrics Society/National Institute on Aging conference on a Research Agenda on Frailty in Older Adults, which brought together a diverse group of clinical and basic scientists to encourage further investigation in this area. This conference was primarily focused on physical and physiological aspects of frailty. Although social and psychological aspects of frailty are critically important and merit future research, these topics were largely beyond the scope of this meeting. Included in this article are sections on the evolving conceptualization and definitions of frailty; physiological underpinnings of frailty, including the potential contributions of inflammatory, endocrine, skeletal muscle, and neurologic system changes; potential molecular and genetic contributors; proposed animal models; and integrative, system biology approaches that may help to facilitate future frailty research. In addition, several specific recommendations as to future directions were developed from suggestions put forth by participants, including recommendations on definition and phenotype development, methodological development to perform clinical studies of individual-system and multiple-system vulnerability to stressors, development of animal and cellular models, application of population-based studies to frailty research, and the development of large collaborative networks in which populations and resources can be shared. This meeting and subsequent article were not meant to be a comprehensive review of frailty research; instead, they were and are meant to provide a more-targeted research agenda-setting process.

Phenotype of frailty: characterization in the women's health and aging studies

BACKGROUND

"Frailty" is an adverse, primarily gerontologic, health condition regarded as frequent with aging and having severe consequences. Although clinicians claim that the extremes of frailty can be easily recognized, a standardized definition of frailty has proved elusive until recently. This article evaluates the cross-validity, criterion validity, and internal validity in the Women's Health and Aging Studies (WHAS) of a discrete measure of frailty recently validated in the Cardiovascular Health Study (CHS).

METHODS

The frailty measure developed in CHS was delineated in the WHAS data sets. Using latent class analysis, we evaluated whether criteria composing the measure aggregate into a syndrome. We verified the criterion validity of the measure by testing whether participants defined as frail were more likely than others to develop adverse geriatric outcomes or to die.

RESULTS

The distributions of frailty in the WHAS and CHS were comparable. In latent class analyses, the measures demonstrated strong internal validity vis à vis stated theory characterizing frailty as a medical syndrome. In proportional hazards models, frail women had a higher risk of developing activities of daily living (ADL) and/or instrumental ADL disability, institutionalization, and death, independently of multiple potentially confounding factors.

CONCLUSIONS

The findings of this study are consistent with the widely held theory that conceptualizes frailty as a syndrome. The frailty definition developed in the CHS is applicable across diverse population samples and identifies a profile of high risk of multiple adverse outcomes.

Variation in the Ciliary Neurotrophic Factor Gene and Muscle Strength in Older Caucasian Women

OBJECTIVES

To determine whether genetic variants in the ciliary neurotrophic factor (CNTF) gene are associated with muscle strength in older women.

DESIGN

Cross-sectional analysis of baseline data from the Women's Health and Aging Studies I (1992) and II (1994), complementary population-based studies.

SETTING

Twelve contiguous ZIP code areas in Baltimore, Maryland.

PARTICIPANTS

Three hundred sixty-three Caucasian, community-dwelling women aged 70 to 79.

MEASUREMENTS

Participants were genotyped at the CNTF locus for eight single nucleotide polymorphisms (SNPs), including the null allele rs1800169. The dependent variables were grip strength and the frailty syndrome, identified as presence of three or more of five frailty indicators (weakness, slowness, weight loss, low physical activity, exhaustion). In addition to genotypes, independent variables of body mass index (BMI) and osteoarthritis of the hands were included.

RESULTS

Using multivariate linear regression, single SNP analysis identified five SNPs significantly associated with grip strength (P<.05), after adjusting for age, BMI, and osteoarthritis. Haplotype analysis was performed, and a single haplotype associated with grip strength was identified (P<.01). The rs1800169 null allele fully explained the association between this haplotype and grip strength under a recessive model, with individuals homozygous for the null allele exhibiting a 3.80-kg lower (95% confidence interval=1.01-6.58) grip strength. No association was seen between the CNTF null allele and frailty.

CONCLUSION

Individuals homozygous for the CNTF null allele had significantly lower grip strength but did not exhibit overt frailty. Larger prospective studies are needed to confirm this finding and extend it to additional populations.

Serum antioxidants, inflammation, and total mortality in older women

The inflammatory cytokine interleukin-6 (IL-6) has been linked to poor health outcomes in older adults. Oxidative stress triggers the production of IL-6, and antioxidant micronutrients play a critical role in decreasing this inflammatory response. The authors sought to identify the relations between serum levels of antioxidant nutrients and IL-6 and mortality in older women. Levels of alpha- and beta-carotene, lycopene, lutein/zeaxanthin, alpha-cryptoxanthin, total carotenoids, retinol, alpha-tocopherol, zinc, and selenium were measured at baseline in 619 participants in Women's Health and Aging Study I (Baltimore, Maryland, 1992-1998). IL-6 was measured at baseline and at follow-up 1 and 2 years later, and all-cause mortality was determined over a 5-year period. Participants with the highest serum levels of alpha-carotene, total carotenoids, and selenium were significantly less likely to be in the highest tertile of serum IL-6 at baseline (p < 0.0001). Those with the lowest levels of alpha- and beta-carotene, lutein/zeaxanthin, and total carotenoids were significantly more likely to have increasing IL-6 levels over a period of 2 years. Those with the lowest selenium levels had a significantly higher risk of total mortality over a period of 5 years (hazard ratio = 1.54, 95% confidence interval: 1.03, 2.32). These findings suggest that specific antioxidant nutrients may play an important role in suppressing IL-6 levels in disabled older women.

Low serum selenium and total carotenoids predict mortality among older women living in the community: the women's health and aging studies

Selenium and the carotenoids play an important role in antioxidant defenses and in the redox regulation involved in inflammation. We tested the hypothesis that low selenium and carotenoids predict mortality in older women living in the community. Women who were enrolled in the Women's Health and Aging Studies I and II in Baltimore, MD (n = 632; 70-79 y old) had serum selenium and carotenoids measured at baseline and were followed for mortality over 60 mo. Median (minimum, maximum) serum selenium and carotenoids were 1.53 (0.73, 2.51) micromol/L and 1.67 (0.13, 9.10) micromol/L; 14.1% of the women died. The 5 major causes of death were heart disease (32.6%), cancer (18.0%), stroke (9.0%), infection (6.7%), and chronic obstructive pulmonary disease (5.6%). Adjusting for age, education, smoking, BMI, poor appetite, and chronic diseases, higher serum selenium [hazard ratio (HR) 0.71, 95% CI 0.56-0.90/1 SD increase in log(e) selenium; P = 0.005] and higher serum total carotenoids (HR 0.77, 95% CI 0.64-0.84/1 SD increase in log(e) total carotenoids; P = 0.009) were associated with a lower risk of mortality. Women living in the community who have higher serum selenium and carotenoids are at a lower risk of death.

IL-6 gene variation is not associated with increased serum levels of IL-6, muscle, weakness, or frailty in older women

Elevated levels of the inflammatory cytokine IL-6 are associated with the development of disability, frailty, and mortality in older adults. These outcomes are likely mediated through inflammatory activity that alters hormones, skeletal muscle, and the immune system. Polymorphic variants in the IL-6 gene influence IL-6 expression. We hypothesized that IL-6 alleles associate with increased serum of IL-6, decreased muscle strength, and frailty, and tested this in the Women's Health and Aging cohorts. We genotyped 463 participants age 70-79, and identified three common IL-6 haplotype blocks for the Caucasian (n=363) and African American (n=100) subsets. Using linear and logistic regression, and adjusting for age, BMI, race, and osteoarthritis, we identified no significant or clinically meaningful relationship between any single IL-6 single nucleotide polymorphism (SNP) or any IL-6 haplotype and serum IL-6 level, grip, knee, or hip strength, or frailty. Given that the promoter SNP (rs1800795) has been reported to influence IL-6 levels and health outcomes, we performed a similar association study in the In Chianti population (n=266) and confirmed lack of association. These results suggest that IL-6 gene variation may not be an important factor in the determination of elevated IL-6 levels and related phenotypes found in older women.

Common promoter polymorphisms of inflammation and thrombosis genes and longevity in older adults: The cardiovascular health study

Inflammatory response genes may influence life span or quality at advanced ages. Using data from the population-based cardiovascular health study (CHS) cohort, we examined the associations between promoter polymorphisms of several inflammation and thrombosis genes with longevity. We ascertained genotypes for interleukin (IL)-6 -174 G/C, beta-fibrinogen -455 G/A, plasminogen activator inhibitor (PAI)-1 -675 4G/5G, and thrombin-activatable fibrinolysis inhibitor (TAFI) -438 G/A in 2224 men and women > or = 65 years old at baseline. During 10 years of follow-up, men with the TAFI -438 A/A genotype had decreased mortality due to all causes, and lived, on average, 0.9 more years of life, or 1.1 more years of healthy life, than men with the -438 G allele. The effects of TAFI -438 G/A in women were smaller and not statistically significant. PAI-1 4G/4G genotype appeared to be associated with lower non-cardiovascular mortality in men, but with greater cardiovascular mortality in women. In exploratory analyses, we observed a possible interaction among anti-inflammatory drugs, interleukin-6 -174 C/C genotype, and longevity. These findings suggest that modulators of fibrinolytic activity may have a generalized influence on aging, and merit further investigation in studies of genetic determinants of human longevity.

Chronic cytomegalovirus infection and inflammation are associated with prevalent frailty in community-dwelling older women

OBJECTIVES

To evaluate the association between asymptomatic chronic cytomegalovirus (CMV) infection and the frailty syndrome and to assess whether inflammation modifies this association.

DESIGN

Cross-sectional analysis.

SETTING

Women's Health and Aging Study I & II, Baltimore, Maryland.

PARTICIPANTS

Seven hundred twenty-four community-dwelling women aged 70 to 79 with baseline measures of CMV, interleukin-6 (IL-6), and frailty status.

MEASUREMENTS

CMV serology and IL-6 concentrations were measured using enzyme-linked immunosorbent assay. Frailty status was based on previously validated criteria: unintentional weight loss, weak grip strength, exhaustion, slow walking speed, and low level of activity. Frail women had three or more of the five components, prefrail women had one or two components, and women who were not frail had none of the components. Multinomial logistic regression adjusted for potential confounders.

RESULTS

Eighty-seven percent of women were CMV seropositive, an indication of chronic infection. CMV was associated with prevalent frailty, adjusting for age, smoking history, elevated body mass index, diabetes mellitus, and congestive heart failure (CMV frail adjusted odds ratio (AOR)=3.2, P=.03; CMV prefrail AOR=1.5, P=.18). IL-6 interacted with CMV, significantly increasing the magnitude of this association (CMV positive and low IL-6 frail AOR=1.5, P=.53; CMV positive and high IL-6 frail AOR=20.3, P=.007; CMV positive and low IL-6 prefrail AOR=0.9, P=.73; CMV positive and high IL-6 prefrail AOR=5.5, P=.001).

CONCLUSION

Chronic CMV infection is associated with prevalent frailty, a state with increased morbidity and mortality in older adults; inflammation enhances this effect. Further prospective studies are needed to establish a causal relationship between CMV, inflammation, and frailty.

Total and differential white blood cell counts and their associations with circulating interleukin-6 levels in community-dwelling older women

BACKGROUND

Interleukin-6 (IL-6) is an inflammatory biomediator, and age-related increases in IL-6 levels are associated with osteoporosis, sarcopenia, disability, and mortality in older adults. Although white blood cells (WBC), or leukocytes, are known to produce IL-6 in vitro, their in vivo relationship with circulating IL-6 levels is not well established.

METHODS

In this cross-sectional analysis of data from the Women's Health and Aging Study I, the authors evaluated the relationships of total WBC and WBC differential (neutrophil, monocyte, lymphocyte, eosinophil, and basophil) counts to circulating IL-6 levels in 619 community-dwelling older women. Potential associations of age, race, and cigarette smoking with total and differential WBC counts and IL-6 levels were also assessed.

RESULTS

Except for lymphocyte and basophil counts, significant associations of total WBC, neutrophil, monocyte, and eosinophil counts with IL-6 levels were identified. These associations remained highly significant after adjustment for age, race, and smoking status. Total WBC, neutrophil, monocyte, and eosinophil counts had significant stepwise increases in four escalating quartiles of IL-6 levels. In addition, age, race, and cigarette smoking were differentially associated with total and differential WBC counts and IL-6 levels.

CONCLUSIONS

Positive in vivo associations of total WBC and its specific subpopulations were identified, including neutrophils, monocytes, and eosinophils, with circulating IL-6 levels in community-dwelling older women. These findings suggest significant contributions of WBC and its subpopulations to circulating IL-6 levels and potential effects from chronic elevation of IL-6 levels to the function of these circulating immune cells that warrant further investigation.

T cell subsets and mortality in older community-dwelling women

The relationship between specific T cell subset alterations and mortality has not been well characterized in older adults. The specific aim was to determine whether specific T cell subsets are associated with an increased risk of death. We conducted a case-control study of T cell subsets (CD4+ and CD8+ T cells, and subsets of these cells defined by expression or non-expression of CD28, CD45RA, and CD45RO) nested within two complementary prospective cohorts of women aged 65 and over living in the community, the Women's Health and Aging Studies (WHAS). Cases consisted of 61 women who died during 5 years of follow-up, and controls consisted of 61 women matched by age, frailty, and morbidities who survived during 7 years of follow-up. There were no significant differences between cases and controls in any of the T cell subsets studied. When analyses were stratified by frailty status, these data suggest that CD8+CD28- lymphocyte counts were significantly higher among women who were frail compared with pre-frail and non-frail women.