Biological Fountain of Youth

March 27, 2015

By Medical Discovery News

The Biological Fountain of Youth

Over 500 years ago, Ponce de Leon landed in Florida as part of his search for the fountain of youth – magical waters that reverse aging, prevent illness, and grant immortality. He never found it, and neither has anyone else. While immortality is still impossible, we have come a long way in understanding the aging process.

We do not know the precise mechanism of aging, but there are some fundamental processes in our bodies that begin to change and this can drive aging. There are several theories of aging under intense scientific investigation.

A widely accepted theory of aging today is called evolutionary senescence, which mainly hinges on the concept of mutation accumulation. As we age, our cells accumulate mutations in our genetic material or DNA, which affects the ability of our cells to replicate and our tissues to regenerate. Also, some of our genes are designed to enhance reproduction early in life, but can cause problems later. Since genes can only be passed on during reproduction, which generally occurs earlier in life, genes that have negative effects later in life are not removed from the population – we are stuck with them! A good example is a gene called p53, which controls the fate of damaged cells by preventing their replication or directing them to die. This is important in preventing cancer in young people, but it may negatively impact our ability to replace aging cells in tissues as we grow older.

Another widely discussed theory centers on the maintenance of our genomes. As we get older, we accumulate damage to our DNA, which affects cellular function and our ability to renew tissues in the body. In a sense, this is a high mileage effect. Take for example the production of free radical molecules. These highly reactive molecules are normally produced in mitochondria, which use oxygen to produce cellular energy, a process that creates free radical molecules as a by-product. These free radical molecules lead to oxidative damage of DNA and other cellular components.

There is also evidence the neuroendocrine system (hormones that affect neurological function) influences aging. For example, a reduction in hormone levels can lead to a lengthening of life, at least in experimental animals. We are beginning to suspect that the insulin-related hormonal pathway may play a significant role in aging, at least in mice. Mutations that reduce the amount of this circulating hormone extend life.

A relatively new model of aging involves the replication of chromosomes as cells divide. When cells replicate, specialized structures at the ends of chromosomes called telomeres are shortened. Shortened telomeres are linked to decreased viability and increased cancer risk. Cells whose telomeres reach a critical length can no longer divide and are described as senescent.

We are expanding our understanding of how aging occurs. The search for a modern-day fountain of youth will require a great deal of dedicated work by biomedical scientists to safely improve and extend human life.

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Testing Your Age

By Medical Discovery News

Jan. 14, 2012

Testing Your Age

Some would argue that a person’s biological age is more indicative of how old they are than their chronological age. If there was a test to tell if someone had the body of a twenty-year-old, how many would take it? Despite a limited understanding of biological age, companies are now testing anyone willing to pay up to $750 to learn their “biological” age.

The problem with this test is people may take the results literally when they shouldn’t. That’s exacerbated by some news media reporting the test can go as far as to tell a client how long they’ll live. These companies are basing their results on something found in all human cells called telomeres, which are structures at the ends of chromosomes.

Chromosomes are made of twisted double stranded molecules of DNA. Telomeres play an important role in protecting DNA because they act as caps on the ends of chromosomes, keeping them from fraying or intertwining, thus preventing DNA mutation.

One of the consequences of aging is every time a cell in the body divides, the telomeres get shorter. When the telomeres get too short, cells can no longer divide, and they die. So, the length of the telomere is a good measurement of a cell’s age and is what some companies are now using to determine a person’s biological age.

The telomere measuring tests use a technology called quantitative real time polymerase chain reaction. From one drop of blood, white blood cells are isolated, broken open, and then the DNA is purified so the telomere length can be measured. This signal is compared to an unaltered gene and then a telomere score is generated. It’s unclear how accurate these tests are on different people.

It’s a fact that people born with shorter than average telomeres have a shorter lifespan, but it’s unknown if longer telomeres equal longer lives. Until statistics are available on what telemere lengths actually predict, these tests can’t tell much.

So, there’s not enough data to support the claims of the companies producing these tests. Some argue the tests provide an opportunity for people with short chromosomes to alter their behavior if necessary, yet there’s concern insurance companies could misuse this information to set life insurance premiums.

Just because a test is available does not necessarily mean it should be used or that there is sufficient data to understand what the results mean. What is already known is lifestyle can help determine lifespan and health. So until telomeres can reveal more, exercising and making healthy food choices are the proven and dependable options.

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