The hall mark of ageing

When solving the problem, dig at the root instead of just hacking the leaves

Anthony, De Angelo

Aging is characterized by a progressive loss of cell and body integrity, leading to impaired function and increased vulnerability to death. This aging process is the primary risk factor for major human diseases including cancer, diabetes, heart attack, and dementia

The Hallmarks of Aging.

  1. Genomic Instability: Generally, our body has genomic stability systems to maintaining the appropriate length and functionality of telomeres, and for ensuring the integrity of DNA. One common characteristic of aging is the accumulation of genetic damage throughout life from both intrinsic and extrinsic factors such as chronological aging, toxin, Ultraviolet, oxidative stress.

2.Telomere shortening

A telomere is the end of a chromosome. Telomere length shortens with age. Telomeres are made of repetitive sequences of non-coding DNA that protect the chromosome from damage. Each time a cell divides, the telomeres become shorter. Eventually, the telomeres become so short that the cell can no longer divide. The progressive shortening of telomeres leads to aging, cell death, or cancer transformation of the body, affecting the health and lifespan of an individual.

3.Epigenetic Alterations

Behaviors and environment can cause changes that affect the way genes work, This phenomenon is called "Epigenetic". Epigenetic changes affect gene expression to turn genes “on” and “off.”

For example, Smoking can result in epigenetic changes. At certain parts of the AHRR gene, smokers tend to have this gene switch off than non-smokers. The difference is greater for heavy smokers and long-term smokers.

4.Loss of Proteostasis means a failure of the protein-building machinery of the cell and the accumulation of misfolded proteins.

5.Deregulated Nutrient-sensing

The ability of cells to sense and respond to fluctuations in nutrient levels is essential for life. Nutrient sensing pathways are related to the anabolism of cells which are commonly deregulated in human metabolic diseases such as diabetes.

An example of nutrient-sensing regulation is During food abundance, nutrient-sensing pathways engage anabolism and storage, while on the contrary insufficiency triggers catabolic pathways such as the mobilization of internal stores through autophagy.

6.Mitochondrial Dysfunction

Free radical species ( Oxidative stress ) can cause progressing mitochondrial dysfunction which in turn causes further mitochondrial deterioration and global cellular damage.

7. Cellular Senescence

Cellular senescence is a stable cell cycle arrest that can be triggered in normal cells in response to various intrinsic and extrinsic stimuli. Senescent cells remain viable, have alterations in metabolic activity and undergo dramatic changes in gene expression and develop a complex senescence-associated secretory phenotype. Cellular senescence can compromise tissue repair and regeneration, thereby contributing toward aging.

8.Stem Cell Exhaustion

As we age, our stem cells eventually lose their ability to divide. Furthermore, we are unable to replace the stem cells that have migrated, differentiated, or died. As a result, we show outward symbols of aging, such as grey hair.

9.Altered Intercellular Communication

Aging also involves changes at the level of intercellular communication such as endocrine, neuroendocrine or neuronal. Thus intercellular signaling tends to be deregulated in aging as inflammatory reactions increase, immunosurveillance against virus and cancer cells declines, thereby affecting the mechanical and functional properties of all tissues.

Knowing all these hallmarks of senescence leads us to new diagnoses and treatments for aging diseases such as telomere length measuring, an inflammation marker, anti-oxidant therapy aiming to measure and slow down the aging process.

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