**Theories of Aging**:
– Stochastic theories: Aging caused by small changes and failure to repair body damages.
– Accumulated damage theory: Introduced by Dr. August Weismann in 1882, stating aging results from the accumulation of elements from the environment or cell metabolism.
– Mutation accumulation theory: Proposed by Peter Medawar in 1952, harmful mutations expressed later in life accumulate due to weak natural selection.
– Free radical theory: Proposed by Rebeca Gerschman in 1945, free radicals damage cell elements causing irreversible damage.
– DNA damage theories: DNA damage is a major cause of age-related diseases, leading to aging due to damage accumulation.
**Biogerontology and Geriatrics**:
– Biogerontology: Focuses on studying the aging process to prevent diseases of aging and prolong healthspan, treating aging as a disease to be directly addressed.
– Geriatrics: Treats existing diseases in aging, distinct from biogerontology in its approach.
– Interdisciplinary research: Biogerontology involves studying causes, effects, and mechanisms of aging, with a focus on biological aging.
**Mechanisms of Aging**:
– DNA Damage Theory: DNA damage and mutations are types of errors in DNA, with inherited deficiencies in DNA repair genes causing accelerated aging.
– Cross-linking Theory: Advanced glycation end-products and aberrant cross-links in aging tissues cause aging by disabling protein functions and inducing replication errors.
– Genetic Theories of Aging: Aging may be programmed within an individual’s genes, dictating cellular longevity and programmed cell death.
– General Imbalance Theories of Aging: Endocrine, nervous, and immune systems decline with age, leading to system failures and contributing to aging.
– Immunological Theory of Aging: The immune system weakens with age, making the organism less able to fight infections and contributing to aging.
**Longevity Predictions and Anti-Aging Strategies**:
– Longevity predictions: Life expectancy in industrialized countries may reach 100 for post-2000 children, with the possibility of unlimited lifespans with aging interventions.
– Anti-Aging Strategies: Mitotech’s SKQ Project focuses on mitochondrial-targeted anti-aging antioxidants, highlighting DNA damage as a primary cause of aging and exploring the role of poly(ADP-ribose) polymerase-1 in longevity.
**Aging and Cancer Research**:
– Aging and Cancer: Studies explore the link between premature aging and cancer, the relationship between DNA repair and lifespan, and the impact of DNA damage on aging and cancerogenesis.
– Recent Advancements: Focus on mitochondrial-targeted anti-aging antioxidants, the role of poly(ADP-ribose) polymerase-1 in longevity, and the study of DNA methylation age of human tissues and cell types.
Biogerontology is the sub-field of gerontology concerned with the biological aging process, its evolutionary origins, and potential means to intervene in the process. The term "biogerontology" was coined by S. Rattan, and came in regular use with the start of the journal BIOGERONTOLOGY in 2000. It involves interdisciplinary research on the causes, effects, and mechanisms of biological aging. Biogerontologist Leonard Hayflick has said that the natural average lifespan for a human is around 92 years and, if humans do not invent new approaches to treat aging, they will be stuck with this lifespan. James Vaupel has predicted that life expectancy in industrialized countries will reach 100 for children born after the year 2000. Many surveyed biogerontologists have predicted life expectancies of more than three centuries for people born after the year 2100. Other scientists, more controversially, suggest the possibility of unlimited lifespans for those currently living. For example, Aubrey de Grey offers the "tentative timeframe" that with adequate funding of research to develop interventions in aging such as strategies for engineered negligible senescence, "we have a 50/50 chance of developing technology within about 25 to 30 years from now that will, under reasonable assumptions about the rate of subsequent improvements in that technology, allow us to stop people from dying of aging at any age". The idea of this approach is to use presently available technology to extend lifespans of currently living humans long enough for future technological progress to resolve any remaining aging-related issues. This concept has been referred to as longevity escape velocity.
Biomedical gerontology, also known as experimental gerontology and life extension, is a sub-discipline of biogerontology endeavoring to slow, prevent, and even reverse aging in both humans and animals.