What is Ageing?
Ageing is the natural process of getting older. It extends from the smallest unicellular organisms to higher life forms such as human beings. Aging leaves the body’s cells with a gradually inadequate nutritional state, lower blood supply and lower metabolic rate. Cells therefore synthesize the materials they need at a much slower rate, and eventually die.
Causes of Ageing
Glucose is one of the molecules that play a large role in the aging process. The membranes of cells have important proteins anchored to both their intracellular and extra cellular surfaces. As the body ages, glucose is randomly added to these proteins, this causes unbreakable linkages between adjacent proteins. The more the body ages, the more linkages that form, resulting in cell membrane stiffness. Cells need their membranes to be flexible as this is not only how they prevent unwanted substances to pass through, but this is also the basis of their nutritional intake.
Collagen fibers strengthen tendons and arteries. Elastin is responsible for the elasticity of skin and other blood vessels. These fibrous proteins also undergo cross-linkage. Cross-linkage in collagen fibers results in inflexible arteries, as do fat deposits. Cross-linkage in elastin results in wrinkles and thickening which contributes to atherosclerosis. Elastin also develops a higher affinity for calcium which also adds to hardening of arteries.
It has been found that cells have their own biological clocks that lead them to die, therefore contributing to the ageing process. Living cells undergo DNA replication and cell division. At the end of a chromosome, there is a section of DNA called a telomere. This region of DNA becomes shorter every time a cell undergoes mitosis (cell division). This is because the enzyme that replicates DNA is not able to replicate an entire strand. Every time replication occurs, DNA cannot be replicated all the way to the end of the strand. If it were not for telomeres, important, instructional DNA would not be replicated during mitosis, and this would lead less and less important information being copied into new cells. Because telomeres are present at the ends of chromosomes, they are the ones that bare the brunt of the processes’ shortcomings. Each time DNA replication occurs, a little less of the telomere is replicated. Eventually this section of DNA is shortened to a critical length, the cell begins to go through senescence (biological term for aging).
DNA is susceptible to chemical toxins such as some hydrocarbons. DNA can also be damaged by, free radicals and particular wavelengths of radiation such as ultra violet rays. Although there are processes which the body carries out to repair DNA, not all damage can be corrected adequately. If damage cannot be repaired, cells begin a process of senescence or apoptosis (cell suicide).
Consequences of Aging
Once cells start the process of senescence or apoptosis, it brings about a loss of functionality in tissues. The body loses its ability to respond to stress from their internal or external environment and is less able to keep its own internal environment in balance. Thus it becomes frail and is increasingly susceptible to disease and eventually dies.
Research on Aging
Ageing is a natural process caused by environmental and biological factors. Medical research in the branchof gerontology, aims to identify all the causes of ageing and is attempting to find ways to stop it.
Some research has found that Carnosine can delay the onset of senescence in some cells by preventing cross linkage in proteins.
“Carnosine’s possible anti-ageing mechanisms are therefore discussed; the evidence suggests that inhibition of the mechanistic target of rapamycin and carbonyl scavenging may be involved.”
Telomerase, an enzyme, has been found to extend the youthful state of cells.
Human Growth Hormone is being tested as a possible means to slow the ageing process, yet results are inconclusive.