Healthy aging in the average human body involves two basic factors. The first is related to the number of times our cells can reproduce before they die off and the second is the extent to which those dead or static cells are allowed to build up in tissues.
Every cell in the body carries the genetic information and chemical markers to inform it how to function, which genes must be switched on or off and when to divide to form another cell. The process of cell division involves the systematic winding of our DNA strands until they are lined up in X shapes with their corresponding pair, unless you’re a man, in which case the twenty-third pair comprises an X and a Y chromosome.
At the ends of each chromosome is a protective cap called a telomere. During cell division, the X shapes are split in half, before travelling along chemical threads to the far sides of the nucleus; a dense region of genetic information inside the cells. Those halves then recreate the missing part of their X shape, and the entire cell cleaves in two.
Every time this happens, the protective telomere caps get smaller, until the chromosome is no longer able to divide. They have reached a natural limit of how many times they can split. This is known as the Hayflick Limit, after Leonard Hayflick, Professor of Anatomy at the University of California in San Francisco, who discovered the phenomenon in 1961.
At this point, the cell either dies off releasing waste products that can cause inflammation, or simply lies in a static state. When all body systems are functioning properly, those dead or senescent cells are flushed from tissues and removed. There are times though, when the chemicals controlling the Hayflick Limit fail, and cells reproduced rapidly and randomly, leading to a higher risk of genetic mistakes. Those mistakes can form the basis of malignant growths and tumours, so it’s important that cells know when to stop dividing.
This continuous cell renewal occurs billions of times within our bodies during our lifetimes, ensuring efficient repair of our essential organs and tissues. Normal embryonic cells can divide about fifty times before they succumb to senescence.
The challenge for scientists studying longevity factors, is to find a method of extending the telomere length and stability without increasing the risks of unwanted genetic mutations. A 2017 study, conducted by Nikolina Skrobot Vidacek and colleagues, suggested that other than hereditary factors, nutrition can impact the length and preservation of telomeres, along with exercise, obesity control and exposure to stress.
Estelle Balan and her colleagues (2018), set out to analyse the impact of diet on longevity, with a view to further studying the links to age related diseases. To achieve this, her team reviewed the results of many studies targeting nutrition in relation to telomere length.
They concluded that positive associations were found in regard to the consumption of “legumes, nuts, seaweed, fruits, and pure fruit juice, dairy products, and coffee, whereas it is negatively associated with consumption of alcohol, red meat, or processed meat”. Their analysis also made specific reference to the negative consequences of long-term consumption of sugars and sweeteners.
The list of those researching the stability of telomeres has grown exponentially in recent years, indicating that there is an abundance of funding available for those willing to find the key to an extended yet healthy life. That’s hardly surprising considering the enormous commercial potential for a non-surgical method of looking and feeling young into old age.
For other researchers, the aim of lengthening telomeres is to generate a longer testing window for cells in laboratories. Helen Blau, Professor of Microbiology and Immunology at Stanford University School of Medicine (2015), used a trigger chemical to produce an enzyme that is naturally present in the body. The enzyme’s main function is to reset the telomeres of sex cells, ready for the next generation of cell division.
This enzyme, telomerase, is present in higher concentrations within egg and sperm cells and is naturally released by stem cells. By contrast, telomerase is in short supply elsewhere in the body. By artificially increasing the abundance of telomerase, the scientists were able to increase the Hayflick Limit by as much as a further forty cell divisions.
Now before we all start jumping for joy at this revolutionary finding, the effect is only temporary. The protection of the chromosome caps lasts for approximately forty-eight hours before dissipating. Despite the limitations, it does provide those researchers working on age related diseases greater opportunity to experiment on cells in the lab, even if it doesn’t further the field of human longevity.
The exciting discovery made in the latter half of 2020 at Tel Aviv University in conjunction with the Shamir Medical Centre, may provide the solution. The study used a kind of oxygen therapy, with the aim of reversing both telomere degradation and preventing the accumulation of dead or inactive cells.
The team, led by Yafit Hachmo, exposed thirty-five healthy volunteers, over the age of sixty-four, to sixty daily hyperbaric oxygen sessions. These repeated bursts of pressurised oxygen were known to induce regeneration in cells that were previously subjected to low oxygen saturation. The team set out to discover whether the treatment would have the same effect on healthy tissues.
Blood samples were taken as a baseline, after thirty sessions, after sixty sessions, and a week or two after the last session. The two determining factors of telomere lengths and accumulated senescent cells were recorded and assessed.
The results were highly encouraging, confirming the scientists’ hypothesis. The bursts of pure oxygen within a pressurised environment increased the chromosome cap length and also cleared away all the dead cells.
While this is great news for patients who have experienced prolonged or sporadic episodes of hypoxia, I can see that this may become another spurious therapy offered by unscrupulous spa owners before the wider effects on the body have been analysed.
Excessive exposure to pure oxygen can be just as harmful as too little. Treatments must be carefully administered and under strictly controlled conditions.
While the underlying principles of lengthening telomeres using hyperbaric oxygen, chambers pave the way for more studies, it could well be open to abuse. In place of salons offering sunbed sessions with a side order of skin cancer, they could switch their focus to anti-aging hyperbaric sessions with a dash of unstable free radicals. If damaged lungs and eyesight is the price to pay for younger looking skin, I think I will resign myself to growing old gracefully.
Let’s hope the researchers can develop safer applications using this discovery and make them available to all instead of only those who can afford the treatments. Until then, the quest for everlasting youth remains just out of reach for us all.