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Related Concept Videos

Aging01:26

Aging

Aging is a complex biological phenomenon influenced by various processes that affect cellular and systemic functions. Several prominent theories attempt to explain its mechanisms, highlighting cellular limitations, oxidative damage, and hormonal changes as central factors in aging.
Cellular Clock Theory
The cellular clock theory posits that the human lifespan is closely tied to the finite capacity of cells to divide, a phenomenon governed by telomeres, which are protective caps at the ends of...
The Effect of Aging on Tissues01:19

The Effect of Aging on Tissues

Several body functions deteriorate with age. The external signs of aging are easily identifiable. For example, the skin becomes dry, less elastic, and thins out, forming wrinkles. The skin of the face begins to appear looser due to a decrease in the levels of elastic and collagen fibers in the connective tissue. Additionally, melanin production in the hair follicle decreases with age, resulting in gray hair. Moreover, the senses of sight and hearing decline, so glasses and hearing aids may...
Characteristics of Life01:23

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, distribution, and taxonomy. The field's scope is extensive and divided into several specialized disciplines, such as anatomy, physiology, ethology, genetics, and many more. All living things share a few key traits, including cellular organization, heritable genetic material and the ability to adapt/evolve, metabolism to regulate energy needs, the...
Pharmacodynamics in Geriatric Patients: Effects of Age01:27

Pharmacodynamics in Geriatric Patients: Effects of Age

Age-related pharmacokinetic changes are extensively documented, but understanding age-related pharmacodynamic alterations is relatively limited. This knowledge gap can be partly attributed to the complexity of developing appropriate measures of drug responses compared to bioanalytical methods for determining drug concentrations.Most information regarding age-related differences in human pharmacodynamics originates from cross-sectional studies. However, these studies assume that observed mean...
Bone Disorders01:29

Bone Disorders

Aging and its effect on bone remodeling is the most common cause of bone disorders. In young and healthy people, bone deposition and resorption happen at an equal rate to maintain optimal bone health.
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
Replicative Cell Senescence02:15

Replicative Cell Senescence

Replicative cell senescence is a property of cells that allows them to divide a finite number of times throughout the organism's lifespan while preventing excessive proliferation. Replicative senescence is associated with the gradual loss of the telomere — short, repetitive DNA sequences found at the end of the chromosomes. Telomeres are bound by a group of proteins to form a protective cap on the ends of chromosomes. Embryonic stem cells express telomerase — an enzyme that adds the telomeric...

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Related Experiment Video

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Measuring Single-Cell Aging with an Imaging-based Biomarker of Chromatin and Epigenetic Aging
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Biological boundaries and biological age.

Jacques Demongeot1

  • 1TIMC-IMAG, UMR CNRS 5525, Team AGIM(3), Faculty of Medicine of Grenoble, University J. Fourier, 38700, La Tronche, France. Jacques.Demongeot@imag.fr

Acta Biotheoretica
|November 13, 2009
PubMed
Summary

Chronologic age is insufficient for understanding organismal development and aging. We propose biological age, based on cellular divisions to the Hayflick

Area of Science:

  • Gerontology and Developmental Biology
  • Cellular Biology and Aging
  • Biophysics and Organismal Lifespan

Background:

  • Chronologic age often fails to accurately reflect an organism's developmental or aging stage.
  • Existing metrics lack precision in quantifying the complex processes of aging and development.
  • The need for a more refined measure of biological state is evident in demographic and medical contexts.

Purpose of the Study:

  • To introduce and define a novel concept: biological age.
  • To explain the limitations of chronologic age in representing an organism's true state.
  • To propose a framework for calculating organismal lifespan based on cellular division limits.

Main Methods:

  • Defined biological age based on the Hayflick limit (maximum cell divisions) of critical tissues and mitochondria.

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  • Introduced a 'cell entropy' or desynchronization index for actively metabolizing interface tissues.
  • Calculated biological age using embryonic and adult age components related to cell cycle duration and limits.

    • Main Results:

    • Biological age is determined by the cumulative cell divisions relative to the Hayflick limit in critical organs.
    • Cell entropy quantifies desynchronization in rapidly renewing tissues like skin, gut, alveoli, and mitochondrial membranes.
    • The study provides a method to calculate global biological lifespan and analyze survival curves.

    Conclusions:

    • Biological age offers a more precise measure of aging and development than chronologic age.
    • Cellular division limits and tissue-specific turnover are key determinants of biological lifespan.
    • This framework allows for a deeper understanding of organismal aging, survival, and developmental phases.