Telomere length and replicative aging in human vascular tissues.

Because repeated injury of the endothelium and subsequent turnover of intimal and medial cells have been implicated in atherosclerosis, we examined telomere length, a marker of somatic cell turnover, in cells from these tissues. Telomere lengths were assessed by Southern analysis of terminal restriction fragments (TRFs) generated by HinfI/Rsa I digestion of human genomic DNA. Mean TRF length decreased as a function of population doublings in human endothelial cell cultures from umbilical veins, iliac arteries, and iliac veins. When endothelial cells were examined for mean TRF length as a function of donor age, there was a significantly greater rate of decrease for cells from iliac arteries than from iliac veins (102 bp/yr vs. 47 bp/yr, respectively, P < 0.05), consistent with higher hemodynamic stress and increased cell turnover in arteries. Moreover, the rate of telomere loss as a function of donor age was greater in the intimal DNA of iliac arteries compared to that of the internal thoracic arteries (147 bp/yr vs. 87 bp/yr, respectively, P < 0.05), a region of the arterial tree subject to less hemodynamic stress. This indicates that the effect is not tissue specific. DNA from the medial tissue of the iliac and internal thoracic arteries showed no significant difference in the rates of decrease, suggesting that chronic stress leading to cellular senescence is more pronounced in the intima than in the media. These observations extend the use of telomere size as a marker for the replicative history of cells and are consistent with a role for focal replicative senescence in cardiovascular diseases.

Muscle-specific expression of Drosophila hsp70 in response to aging and oxidative stress.

Induction of Drosophila hsp70 protein was detected during aging in flight muscle and leg muscle in the absence of heat shock, using an hsp70-specific monoclonal antibody, and in transgenic flies containing hsp70-beta-galactosidase fusion protein reporter constructs. While hsp70 and reporter proteins were induced during aging, hsp70 message levels were not, indicating that aging-specific induction is primarily posttranscriptional. In contrast, hsp22 and hsp23 were found to be induced during aging at the RNA level and with a broader tissue distribution. The same muscle-specific hsp70 reporter expression pattern was observed in young flies mutant for catalase (H2O2:H2O2 oxidoreductase, EC 1.11.1.6). In catalase (cat) hypomorphic lines where flies survived to older ages, the time course of hsp70 reporter expression during aging was accelerated, and the initial and ultimate levels of expression were increased. The hsp70 reporter was also induced in young flies mutant for copper/zinc superoxide dismutase (superoxide:superoxide oxidoreductase, EC 1.15.1.1). Taken together, the results suggest that aging-specific hsp70 expression may be a result of oxidative damage.

A biomarker that identifies senescent human cells in culture and in aging skin in vivo.

Normal somatic cells invariably enter a state of irreversibly arrested growth and altered function after a finite number of divisions. This process, termed replicative senescence, is thought to be a tumor-suppressive mechanism and an underlying cause of aging. There is ample evidence that escape from senescence, or immortality, is important for malignant transformation. By contrast, the role of replicative senescence in organismic aging is controversial. Studies on cells cultured from donors of different ages, genetic backgrounds, or species suggest that senescence occurs in vivo and that organismic lifespan and cell replicative lifespan are under common genetic control. However, senescent cells cannot be distinguished from quiescent or terminally differentiated cells in tissues. Thus, evidence that senescent cells exist and accumulate with age in vivo is lacking. We show that several human cells express a beta-galactosidase, histochemically detectable at pH 6, upon senescence in culture. This marker was expressed by senescent, but not presenescent, fibroblasts and keratinocytes but was absent from quiescent fibroblasts and terminally differentiated keratinocytes. It was also absent from immortal cells but was induced by genetic manipulations that reversed immortality. In skin samples from human donors of different age, there was an age-dependent increase in this marker in dermal fibroblasts and epidermal keratinocytes. This marker provides in situ evidence that senescent cells may exist and accumulate with age in vivo.

Electro-mechanical coupling in the aging heart: role of the Late Na+ current

The aging myopathy manifests itself with diastolic dysfunction and preserved ejection fraction. However, the difficulty in defining myocardial aging and the mechanisms involved complicates the recognition of the cellular processes underlying impaired diastolic relaxation. We raised the possibility that, in a mouse model of physiological aging, defects in the electromechanical properties of cardiomyocytes are important determinants of the diastolic properties of the myocardium, independently from changes in the structural composition of the muscle and collagen framework. Here we show that an increase in the late Na+ current (INaL) in aging cardiomyocytes prolongs the action potential (AP) and influences the temporal kinetics of Ca2+ cycling and cell shortening. These alterations increase force development and passive tension. Inhibition of INaL shortens the AP and corrects the dynamics of Ca2+ transient, cell contraction and relaxation. Similarly, repolarization and diastolic tension of the senescent myocardium are partly restored. INaL offers inotropic support, but negatively interferes with cellular and ventricular compliance, providing a new perspective of the biology of myocardial aging and the etiology of the defective cardiac performance in the elderly.

Mobility and Aging in Denver, Colorado: Travel Behavior, Mobility Barriers, and Perceptions of Transit

The number of seniors in the U.S. today is growing rapidly because of longer life expectancies and the aging Baby Boomer generation. This age groups' travel behavior will have substantial impacts on transportation, economics, safety, and the environment. This research used a mixed-methods approach to address issues of mobility and aging in Denver, Colorado. A quantitative approach was used to answer broad questions about travel behavior and the effects of age, gender, work status, disability, residential location and socio-economic status on mobility. Qualitative interviews with seniors in the Denver metro area were conducted to identify barriers to mobility, decision-making processes and travel decisions, and seniors' perceptions of public transit. The results of the quantitative and qualitative analyses show that residential location is an important variable for determining seniors' travel behaviors and transportation options. Perceptions of public transit were positive, but accessibility and information barriers exist that prevent older adult from using transit. The findings of this study will help to provide transportation and service recommendations to policymakers and planners in the Denver area as well as to inform studies of other North American cities with large aging populations.

Challenges and Opportunities in Managing the Aging Workforce: An Investigation of the Federal Emergency Management Agency

The aging workforce is becoming the majority of the working population in the United States. Although the literature on the aging workforce is sizable, little exists on how public agencies use the older workers. This capstone project examines the challenges and opportunities related to the employment of older workers as seen through a case study of the Federal Emergency Management Agency (FEMA). Knowledge gained from a synthesis of the literature review with survey data collected and analyzed will enable HR professionals to better understand the demographic, economic, regulatory, and intellectual influences of the aging workforce. The results from the survey of FEMA employees suggest a basis to plan and implement successful hiring and retention policies related to the aging workforce.

Understanding Seniors' Perceptions and Stereotypes of Aging

Research suggests there is a connection between stereotypes, beliefs, and behavior in older individuals. To explore this link of stereotypes affecting beliefs and beliefs affecting behavior, we interviewed young (age 60 to 75) seniors in an effort to further examine these relationships. Semistructured qualitative interviews were conducted with 20 seniors. Questions focused on the broad themes of aging stereotypes and attitudes towards active living. Responses from the participants indicated the variety of opinions and beliefs seniors hold about the aging process. Intriguing results emerged on the topic of role models. Participants often had someone in their lives who represented what it means to age successfully. Generally, this was an individual older than themselves, active, vigorous, and illustrative of the high quality of life that is possible into a very late age. In addition, these individuals provide a direct contrast to the most negative stereotypes of aging.

Investigating the thymopoiesis stimulating property of interleukin-21 in aging mice

La vaccination est largement utilisée pour la génération de lymphocytes T spécifiques contre les tumeurs. Malheureusement, cette stratégie n'est pas adaptée aux personnes âgées car leur thymus régresse avec l'âge conduisant ainsi à une baisse dans la production de cellules T et à l'accumulation de cellules immunitaires âgées ayant des défauts liés à leurs stimulations. Comme il a été démontré auparavant que L’IL-21 est capable d’induire des fonctions thymiques, nous avons émis l’hypothèse que l’injection d’IL-21 à des souris âgées stimulera la thymopoïèse. Nos résultats montrent que l’administration de l’IL-21 augmente le nombre absolu de thymocytes chez les souris âgées et augmente la migration de ces cellules vers la périphérie ou ils contribuent à la diversité du TCR. De plus les cellules T en périphérie expriment un niveau plus élevé de miR181-a, et par conséquent moins de phosphatase comme SHP2, DUSP5/6 qui inhibent le TCR. En vaccinant des souris âgées avec le peptide Trp2, les souris traitées avec l’IL-21 montrent un retard dans la croissance des cellules B16 tumorales. Cette étude montre que l’IL-21 pourrait être utilisé comme stratégie pour le rétablissement du systeme immunitaire chez les personnes âgées.

Aging and the governance of the healthcare system in Japan. Bruegel Working Paper 2014/14, December 2014

Japan is the most rapidly aging country in the world. This is evidence that the social security system, which consists of the pension system, healthcare system and other programmes, has been working well. The population is shrinking because of a falling birth rate. It is expected that the population will fall from 128 million in 2010 to 87 million in 2060. During this period, the ratio of people aged 65 or over will rise from 23 percent to 39.9 percent. Japan’s age dependency ratio was 62 in 2013, the highest among advanced nations. It is expected to rise sharply to 94 in 2050 (see Figure 1 on page 4). A total reform of the Japanese social security system, therefore, is inevitable. From the point of view of fiscal reconstruction, reform of the healthcare system is the most important issue. The biggest problem in the healthcare system is that both the funding system and the care-delivery system are extremely fragmented. The government is planning its reform of the healthcare system based on the principle of integration. Other advanced economies could learn from the Japanese experience.

Las necesidades de los ancianos hispanos : audiencia ante el Comité Selecto sobre la Vejez, Cámara de Representantes, 95 Congreso, segunda sesión, marzo 28, 1978, Miami, Florida = Needs of the Hispanic elderly : hearing before the Select Committee on Aging, House of Representatives, Ninety-fifth Congress, second session, March 28, 1978, Miami, Fla.

"Comm. pub. no. 95-152."

The National Institute on Aging macroeconomic-demographic model.

Mode of access: Internet.

Diabetes and aging : selected annotations /

Mode of access: Internet.

Health of an aging America : 1989 bibliography : a guide to reports about older Americans.

Mode of access: Internet.

White House Conference on Aging, January 9-12, 1961: background paper on health and medical care.

Cover title.

Problems of the aging : hearings before the Subcommittee on Federal and State Activities of the Special Committee on Aging, United States Senate, Eighty-seventh Congress, first session on problems of the aging. August 23 and 24 1961.

Hearings held Aug. 23, 1961- December 6, 1961.