8week 1session (2)

The Two Theories of Aging

  • Programmed Theory: Aging progresses according to an inherent program and has a limited lifespan.

  • Damage or Error Theory: Aging occurs due to the accumulation of damage or errors caused by external factors.

Jeanne Calment's Case

  • Recorded as the world's longest-lived person, surviving until the age of 122.

  • Lived a long life despite having various lifestyle habits. Jeanne Calment, recorded as the world's longest-lived person, survived until the age of 122. Despite her longevity, she had various lifestyle habits that some might consider unhealthy, such as smoking and a diet high in calories. However, she maintained a positive outlook on life and enjoyed activities that contributed to her happiness. Her unique case suggests that the interplay between genetics, lifestyle, and external factors can significantly influence the aging process, highlighting that longevity may not solely depend on one’s lifestyle choices.

Impact of External Factors

  • An individual's aging rate can vary depending on external factors (lifestyle, environment, etc.).

  • Aging can progress differently even with the same DNA depending on the environment.

Oxidative Stress and Aging

  • Oxidative Stress: A phenomenon where cells suffer damage from reactive oxygen species.

  • Reactive oxygen species lead to decreased cellular function.

  • Example: Unstable electron movement in oxygen causes oxidation.

Characteristics of Long-Living Organisms

  • Long-lived organisms have resistance mechanisms to aging.

  • Examples:

    • Aquatic Tortoise: 130 years

    • Hydra: Indefinite lifespan

    • Polar Bear: 500 years

    • Naked Mole Rat: Lifespan of over 30 years

  • Their biological mechanisms resist oxidative stress.

Causes of Reactive Oxygen Species

  • UV exposure, air pollution, radiation, smoking, etc.

  • During respiration, 3-5% of oxygen is converted into reactive oxygen species.

Mitochondrial Dysfunction

  • Mitochondria: The powerhouses of cells responsible for energy production.

  • Damage from reactive oxygen species affects mitochondria.

  • Dysfunction is associated with aging-related diseases.

Epigenetic Changes

  • Changes in compounds that regulate gene expression.

  • DNA methylation, histone modification, etc., influence aging.

  • Epigenetic Clock: A system that predicts biological age. These alterations can greatly influence aging. DNA methylation involves the addition of methyl groups to DNA, which can suppress gene activity. Increased methylation is often associated with aging cells. Histone modification refers to changes in histones (proteins around which DNA is wrapped), impacting how tightly or loosely the DNA is packaged, thereby affecting gene expression. The Epigenetic Clock uses various epigenetic markers to predict the biological age of an individual, showing whether a person's biological age aligns with their chronological age and reflecting their health status.

Loss of Protein Homeostasis

  • Aging is accelerated when cells lose balance in protein synthesis and degradation.

  • Accumulation of misfolded proteins.

Imbalance in Nutrient Sensing

  • Regulation of nutrients is necessary during metabolic processes.

  • Imbalances in nutrient sensing can impact aging.

Summary of the Two Main Theories of Aging

  • Programmed Theory: Lifespan extension through an inherent program.

  • Damage/Error Theory: Aging is accelerated by the accumulation of damage or errors caused by external factors.

Rejuvenation Methodologies

  • Epigenetic Reprogramming: Reprogramming aging cells.

  • Caloric Restriction and Exercise: Regulation of metabolism.

  • Development of senolytics and senomorphic treatments to eliminate aging cells.

  • Blood Manipulation: Research on reversing aging using younger blood. This innovative area explores the potential for using younger blood or its components to reverse some aging processes. Studies suggest that factors present in younger blood may help rejuvenate aged tissues, leading to possible therapies for age-related decline in health.

Conclusion

  • Understanding theories and mechanisms of aging can contribute to the treatment of aging-related diseases.

  • Various studies are ongoing, and results will gradually be revealed.