Researchers have partially reversed a process of cellular aging in humans

To study how the experimental method worked, participants were placed in a hyperbaric oxygen chamber for five 90-minute sessions per week, for three months. The result: some of the telomeres in their cells were lengthened by up to 20%. It’s a puzzling claim – a reversal process that many other researchers have attempted in the past, to no avail. However, it should be considered that the study concerns a small sample of individuals, and that the results must still be reproduced by other teams before being validated. The study was published in the journal Aging.

Nonetheless, the fact that hyperbaric oxygen therapy appears to affect telomere length is a finding that merits further study. Principal investigator Shair Efrati, a physician from the Faculty of Medicine and the Sagol School of neurosciences from Tel Aviv University, explained how they got the inspiration for this experience.

Inspiration from space

« After the twin experiment performed by NASA, where one of the twins was sent to space and the other remained on Earth, demonstrated a significant difference in the length of their telomeres, we realized that changes in the external environment can affect the central cellular changes that occur during aging Efrati said.

Telomeres repeat pieces of genetic code that act as the DNA equivalent of the piece of plastic or metal that covers the end of a shoe lace. They copy each other with the rest of the chromosomes every time a cell divides (mitosis). Yet with each replication, tiny snippets of code from the very last part of the sequence fail to form the new copy, leaving the freshly copied chromosome a little shorter than its predecessor.

« As anyone who has lost the ‘hood’ of their lace knows, it doesn’t take long for the lace to lose its integrity. Likewise, shorter telomeres place sequences further in the chromosome, which increases the risk of dangerous mutations. », Explains Efrati.

These mutations coincide with changes that predispose us to a number of age-related conditions, including diseases like cancer. This doesn’t necessarily mean that we are getting older because our telomeres are shrinking, but there is a link between telomere length and general health, which researchers want to study further.

« There is a correlation between longer telomeres and better cell performance Adds Efriti. There are many ways to accelerate the erosion of our telomeres. Not getting enough sleep, for example, as well as consuming too much processed foods, and maybe even having children (for women). Slowing this loss therefore requires effort, such as exercising regularly and eating healthy.

But the real feat would be to turn our chromosomal hourglass completely, and “regaining” lost telomere sections could be a good place to start. The fact that the tissues that line our gut do so naturally by using an enzyme called telomerase has fueled research over the years. The attempts to accomplish this task have been marked by many promising studies. For example, a gene therapy experiment in mice has shown that it might one day be feasible in humans. More recently, stem cells from a centenary woman saw their telomeres completely reset following “cellular reprogramming”.

20% rejuvenated telomeres

Some studies have shown that it is possible to obtain tiny increases, of the order of a few percent, thanks in particular to food supplements such as vitamin D. But while there are already many on the market hypothetical promises to reverse aging in humans, the reality of available rejuvenating therapies falls far short of those expectations.

This is why this new study is attracting so much attention. Far from the few percent cited above, the researchers report here that the telomeres of the white blood cells taken from the 26 subjects had regained about a fifth of their lost length, a gain of about 20%.

To achieve this, they relied solely on hyperbaric oxygen therapy (HBOT) – the absorption of pure oxygen by sitting in a pressurized chamber for long periods of time; in this case, five 90-minute sessions per week, for a total of three months.

It should be noted that this method has generated controversy in the past, as some claimed that it could treat a whole range of diseases. This is usually the kind of therapy offered to a diver who ascends too quickly from the depths of the ocean, or to kill certain oxygen-sensitive bacteria in the case of certain hard-to-treat injuries. But oxygen-rich environments also create a strange paradox, one where the body desperately induces a host of genetic and molecular changes that typically occur in an oxygen-poor environment.

In this study, the researchers were able to show that the genetic changes induced by HBOT extended the telomeres and also had a potentially positive effect on the health of the tissues themselves. A slightly reduced sample of volunteers also showed a significant decrease in the number of senescent T cells, tissues that are a vital part of our immune system’s targeted response against invaders.

« Now that we have demonstrated the opposite effect of aging on the cohort studied using the predefined HBOT protocol, further studies will be needed in order to optimize the specific protocol for each individual. Efrati said.

In one Press release of the Sagol Center for Hyperbaric Medicine and Research, Efrati says understanding telomere shortening is “considered the ‘holy grail’ of the biology of aging.” As important as telomere shortening seems to be in the biological mechanism of aging, it is certainly only a tiny part of the mystery. This study is nevertheless very encouraging for understanding at least one of the mechanisms involved and, perhaps, already developing therapies for rejuvenation or the fight against certain forms of cancer.

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