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Huber R Warner

Publications and source records attributed to Huber R Warner.

14 recordsLinked to original sources

Is cell death and replacement a factor in aging?

The central theme of the 3rd International Conference on Functional Genomics of Ageing was tissue regeneration as a remedial strategy to address age-related cellular damage and the pathology that ensues. The conference included sessions on maintaining genome integrity and the potential of stem cells to restore function to damaged tissues. In addition to several human syndromes that appear to reflect accelerated ageing, there are now a number of mouse models that prematurely display phenotypes associated with ageing. The intent of this summary presented at the end of the conference was to: (1) discuss various human syndromes and mouse models of accelerated ageing; (2) evaluate whether the phenotypes displayed might result from an elevated rate of cell death coupled with an inability to adequately maintain cell number in various tissues with increasing age; and (3) discuss whether similar events may be occurring during normal ageing, albeit much more slowly.

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Scientific and ethical concerns regarding engineering human longevity.

The goal of biogerontological research is to elucidate the biological factors underlying adverse age-related changes in structure and function of molecules, cells, tissues, and organisms. In spite of the considerable progress achieved so far, it is still too early to predict what strategies will be both safe and effective at preventing, delaying, or reversing these changes in humans, and whether such strategies will also increase longevity.

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Developing a research agenda in biogerontology: basic mechanisms.

The National Institute on Aging (NIA) began operation in 1975, splitting off from the National Institute of Child Health and Human Development. The first 10 years of NIA's existence were characterized by funding descriptive and discovery research, as the field by then had not come of age. With the isolation of long-lived animal mutants and the application of the tools of molecular biology (including whole-genome sequencing) and transgenic technology to biogerontology research, the situation has changed dramatically since then, and aging-related research has become increasingly mechanistic and respectable. This transition has been aided by research initiatives implemented by NIA staff, and the goal of this article is to describe how NIA develops such research initiatives using research progress made in biogerontology over the past 20 years as the basis for the discussion.

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The future of aging therapies.

Advances in understanding aging processes and their consequences are leading to the development of therapies to slow or reverse adverse changes formerly considered to be "normal" aging and processes that underlie multiple age-related conditions. Estimating the effectiveness of candidate aging therapies, whose effects on human aging may require many years to determine, is a particular challenge. Strategies for identifying candidate interventions can be developed through multiple approaches, including the screening of molecular targets and pathways in vitro and in animal models, informed as well by evidence from human genetic and epidemiologic data. A number of recently established programs and networks can serve as resources for such research. For all these research approaches, from in vitro molecular studies to clinical trials, contributions of cell and molecular biology are crucial and offer the prospect of therapeutic advances that address fundamental biological processes as well as the clinically important challenges of aging.

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Longevity genes: from primitive organisms to humans.

Recent results indicate that the longevity of both invertebrates and vertebrates can be altered through genetic manipulation and pharmacological intervention. Most of these interventions involve alterations of one or more of the following: insulin/IGF-I signaling pathway, caloric intake, stress resistance and nuclear structure. How longevity regulation relates to aging per se is less clear, but longevity increases are usually accompanied by extended periods of good health. How these results will translate to primate aging and longevity remains to be shown.

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Current status of efforts to measure and modulate the biological rate of aging.

Biomarkers of aging would be highly desirable, but so far, a definitive panel of biomarkers to predict mortality risk has not been obtained, even though many traits that vary with age have been identified. This lack hinders the search for interventions that may retard the rate of aging in mammals. The recent discovery and characterization of many longevity genes in animal model systems, such as nematodes, fruit flies, and mice, are providing new targets for research by providing insight into mechanisms of longevity regulation in these model systems. It is hoped that this will ultimately lead to interventions to delay the development of age-related pathology in humans.

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Subfield history: use of model organisms in the search for human aging genes.

The National Institute on Aging (NIA) started a program in 1993 to identify genes involved in the regulation of longevity in a variety of species, including yeast, nematodes, fruit flies, and mice. The initial success of this program has attracted the interest of many investigators working with these organisms. Of primary interest are single-gene mutants that have identified genes and processes involved in longevity regulation across species. These processes include the insulin-like signaling pathway, stress resistance, and most recently, chromosome and nuclear architecture. Mutations in genes that regulate these processes indirectly are also being identified in this program. The ultimate goal of this program is to extend these results to humans to identify the major biological risk factors for age-related decline of function in human physiological systems.

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Models of accelerated ageing can be informative about the molecular mechanisms of ageing and/or age-related pathology.

During the past ten years considerable progress has been made in discovering genes that regulate longevity by identifying single gene mutations that lead to increased longevity. The initial success in nematodes was quickly followed by comparable success in fruit flies and mice. In contrast, mutations that cause a decrease in longevity have been largely discounted as unlikely to be informative about aging mechanisms. However, the recent creation of several mutant mouse models that develop a variety of aging-like phenotypes and die prematurely, suggests that such models may be useful in understanding aging mechanisms, particularly as they relate to progressive tissue and organ dysfunction. A possible common feature of these models may be an imbalance between loss of cells by apoptosis and subsequent cell replacement, leading gradually to a net loss of cells in multiple tissues.

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Is there an antiaging medicine?

In spite of considerable hype to the contrary, there is no convincing evidence that currently existing so-called "antiaging" remedies promoted by a variety of companies and other organizations can slow aging or increase longevity in humans. Nevertheless, a variety of experiments with laboratory animals indicate that aging rates and life expectancy can be altered. Research going back to the 1930s has shown that caloric restriction (also called dietary restriction) extends life expectancy by 30-40% in experimental animals, presumably at least partially by delaying the occurrence of age-dependent diseases. Mutations that decrease production of insulin growth factor I in laboratory mammals, and those that decrease insulin-like signaling in nematodes and fruit flies, have increased life expectancy as well. Other general strategies that appear promising include interventions that reduce oxidative stress and/or increase resistance to stress; hormone and cell replacement therapies may also have value in dealing with specific age-related pathologies. This article reports the findings of a consensus workshop that discussed what is known about existing and future interventions to slow, stop, or reverse aging in animals, and how these might be applied to humans through future research.

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Recent progress in understanding the relationships among aging, replicative senescence, cell turnover and cancer.

The link between aging and cancer is more than just the increasing accumulation of mutations with time. Recent research provides evidence that senescent cells are not merely passive bystanders, but may promote cancer through degradation of the tissue microenvironment. Another critical factor in the relationship between aging and cancer is p53 function; its activity level is apparently finely tuned to suppress cancer while regulating both apoptosis and the replacement of damaged cells through stem cell proliferation. The deacetylase activity of the sir2 gene product plays a role in longevity regulation in invertebrates, and also regulates p53 function in mammals, implying yet another link between aging and cancer in mammals.

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