Scientists have conducted studies on molecular and cellular processes controlling chronological and biological age changes among different individuals for the past few years. Then, they came up with nine interconnected Hallmarks of Aging. It is primarily associated with human genetics that is balanced through environmental factors. These nine hallmarks explain the damage that happens with age and eventually leads to age-associated complications.
Genomic instability
When your body is exposed to chemicals, smoke, and other exogenous agents with the passing of time, it damages your genome. It further leads to DNA replication issues and oxidative stress. Even though plenty of DNA repair mechanisms have developed, damaging of DNA accumulates throughout your life course. Furthermore, DNA issues cause mutation in cells that can cause cancer formation.
Telomere attrition
The main function of telomeres is to protect terminal ends of human chromosomes from collapsing. Basic DNA replication mechanisms present in your cells do not possess the capability to completely copy the ends of your DNA; thus, repetitive DNA sequences in telomere regions deteriorate with every cell division. When a greater number of replications occur, it causes cell growth arrest and tissue regeneration ability gets restricted with your age.
Epigenetic alterations
You might be wondering how tissue and organs present in your body differs from one another when genetic details encoded in the DNA is similar to that of all cells in your body. Besides, DNA modification with epigenetic instructions that helps to enhance and suppress specific genes expression is based on different tissue types. Hallmarks of Aging often include epigenetic alterations that create changes in your gene expression, further affecting normal cellular functioning.
Loss of proteostasis
Proteins constantly synthesize in human body cells and decline through a process called protein proteostasis, or homeostasis. Proteins play a vital role that must assemble in the right way to carry out important cellular functions and fold proteins into appropriate shapes. Many mechanisms have been developed to stabilize and restore folded proteins perfectly and eliminate improperly shaped proteins that cause cell damage. When these mechanisms fail to work overtime, damaged protein components can lead to cell dysfunction, cell toxicity, and diseases such as Alzheimer’s.
Deregulated nutrient sensing
When your body has abundant nutrients, cells, and tissues present inside, help to store energy and boost growth. However, scarcity of nutrients activates homeostasis and repair mechanisms. When deregulated nutrient sensing happens during the aging process, your cells fail to respond to signs correctly associated with cell growth, energy production, and other vital cell functions.
Mitochondrial dysfunction
Reactive oxygen species (ROS) act as a natural byproduct that produces energy in the mitochondria. Although it is vital for cellular signaling; however, a higher dose of ROS can damage your cells. According to theories, increasing ROS production leads to mitochondrial dysfunction and cellular deterioration. It further causes age-related problems like myopathies and neuropathies.
Cellular senescence
Stress in cells, telomere reduction, and DNA damage lead to stable growth arrest known as cellular senescence. Senescent cells change during their function, most importantly, at the time of molecular secretion. This further damage the cells’ environment and causes chronic tissue inflammation, leading to geriatric conditions such as kidney dysfunction and osteoarthritis.
Stem cell exhaustion
One of the major consequences of Hallmarks of Aging is Stem cell exhaustion. Aging can worsen your injury recovery and decrease the stem cell’s ability to regenerate damaged tissues.
Altered intercellular communication
Proper growth and functionality require constant cell information transfer within each other and molecular secretion signaling to its neighboring cells. However, aging changes the signaling process and leads to chronic tissue inflammation, immune system failure, and increased infection and cancer chances.
