Successful Aging Is Possible
The old model of aging is simply that, old. We no longer have to age in a nursing home with a poor quality of life. There are advances in science that allow us to slow and in some cases reverse the aging process. The first step is to determine what aging is and where we are in the process. An epigenetic clock is a biochemical test that is a test used to measure the age of an individual. The test utilizes DNA methylation levels.
History Epigenetic Clock
It has been know since the late 1960s that age has a strong impact on levels of DNA methylation. The first demonstration that the DNA methylation levels found in saliva generated age predictors which were accurate was published in 2011 by a UCLA team which included Steve Horvath. The biggest innovation made by Horvath’s epigenetic clock was in the broad applicability.
What Does Successful Aging Look Like
So now you have gone through some form of benchmark testing. You have an idea of your physical age in relationship to your chronological age. How do you start the path towards successful aging and what does that even mean?
Over the past few years the term “successful aging” has become a buzz phrase that has grown in popularity. During some point in people’s lives they become concerned about the impacts of aging either for themselves or for those they care about. Some of the questions that arise are:
1. What is reasonable to expect
2. What can be avoided
3. How can I or my loved on adapt
Recent research has raised some interesting paradoxes about how we view old age as well as how people really age. The words successful aging weren’t relevant until 1987 after work by scientists John Wallis Rowe and Robert Kahn was published that year. There are 3 main factors impacting successful aging:
(1) Avoiding disability or disease
(2) Maintaining a high level of cognitive and physical abilities
(3) Continued interactions with others in meaningful ways.
What Are the Extrinsic and Intrinsic Factors of Successful Aging
Importantly, the research done by Rowe and Kahn showed that if someone wants to age successfully both intrinsic genetic as well as extrinsic lifestyle factors have to be considered. Exercise, diet and other personal habits or Extrinsic factors as well as psychosocial aspects are underestimated aging influences. Many people simply look at genetics to guide aging.
Having said that, the exact definition for successful aging is open for debate. We don’t even know if aging is a process or simply an outcome. Researchers have offered over 80 unique and different operational definitions of successful aging, with some estimating that only 1% of people achieve successful aging, while others estimate that close to 90% of people can achieve it.
Despite these discrepancies, most people can easily identify someone who exemplifies successful aging, without subjecting that person to medical testing or any psychological evaluation. Thus, successful aging is often something we simply “know it when we see it.”
Telomeres and Aging
Chromosomes contain some critical parts know as Telomeres. Telomeres act to protect chromosomes as well as make sure that when DNA replicates it does so effectively. When there are mutations or defects with telomeres this can cause a myriad of health complications. However, researchers aim to use telomeres as therapeutic targets for the treatment of some of these complications.
The enzyme that is responsible for the lengthening of telomeres is known as Telomerase. This increases the time it takes for the chromosomes of a cell to reach the Hayflick limit. Due to this, telomerase activity affects cellular aging and is linked to the development of cancer.
Recent studies have aimed to evaluate the potential for telomerase to act as a therapeutic target to reduce the effect of telomere shortening and reduce the risk of certain cancers. Telomerase can possess oncogenic properties; illustrated by the associations between the development of certain cancers (I.e. urothelial carcinomas) and mutations in the telomerase promoter.
These mutations can lead to abnormally high levels of the telomerase catalytic subunit; telomerase reverse transcriptase (TERT). Due to these properties, pharmacologically inhibiting telomerase could be a therapeutic option against certain cancers. Inhibiting telomerase can be done by:
- Directly targeting the hTERT component of telomerase
- Directly targeting the TERC component of telomerase
- Using immunotherapies to target telomerase
- Unintended off-target side effects from chemotherapy that targets telomerase
Manipulating telomerase may also be used to improve the symptoms of certain cardiovascular diseases. Senescence of various cardiovascular cells, in particular, endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), has a role in the development of vascular lesions, resulting in the development of atherosclerotic plaques.
Studies have shown that the regulation of telomerase can reduce and even reverse the senescence of vascular cells which can restore their function. The activation of TERT reduces the proliferation and hypoxia of VSMCs, it also increases antioxidants and the anti-senescent activity in ECs. All of these changes lead to a reduction of atherosclerosis.