You may have seen some viral videos of extremely fit, white-haired senior citizens working out like they are still in their 20s or 30s.
They can be seen lifting heavy weights or doing pull-ups easily and nimbly, with well-toned and muscular bodies. Whether they are male or female, it is an impressive feat for people in their 60s and beyond.
Although these individuals seem unusual, the idea of seniors remaining as fit and healthy as their younger counterparts may not be as uncommon in the future, if experts in the field of human longevity are to be believed.
One of these experts include Harvard geneticist Professor Dr David Sinclair, who has been studying the possibility of age reversal in humans for decades. His bestselling book, Lifespan: Why We Age, and Why We Don’t Have To, theorises that ageing is like a disease.
If it is curable, then we might be able to treat it just like any other disease, which could have “the biggest impact on human health since antibiotics and public sanitation”. Before going further though, there are questions some of us might ask, e.g. if being able to reverse ageing implies that we will live longer than before, is it natural?
Does it go against our belief systems? Shouldn’t we just accept that humans aren’t immortal and just allow life to take its natural course? But the primary goal of researchers like Prof Sinclair is to improve our quality of life as we age.
Ageing itself isn’t a bad thing, but there are disadvantages that come with it, such as increased risk of illnesses, immobility and frailty. Thus, it’s much less about chasing a fountain of youth, and more about finding ways to prevent old-age problems that stop seniors from enjoying a full and active lifestyle in their golden years.
Scientists classify cells as the simplest level of organisation in a living organism. Ageing, on a cellular level, is often defined as the accumulation of destructive changes caused by changes to gene expression that gradually shift our cells to an aged state. Based on years of study, researchers believe that they have found some key reasons as to why humans age.
Reset to youth
These include a reduction of energy generated by the mitochondria (the power plants inside our cells), the shortening of telomeres (the “caps” on the end of chromosomes), a loss of stem cells, and an accumulation of so-called senescent cells (non-functioning “zombie” cells that linger in our skin and tissues).
While genetic reprogramming to regain youthful functions is one avenue of scientific exploration, researchers are also taking inspiration from creatures like the immortal jellyfish Turritopsis dohrnii that can effectively reset its development and revert to a younger stage.
Prof Sinclair believes that maintaining a youthful appearance in old age involves reactivating genes called sirtuins – descendants of an ancient survival circuit. Sirtuins, he claims, are both the cause and the solution to ageing.
These genes can be turned on by modifying your lifestyle, such as intermittent fasting, or by taking dietary supplements that increase NAD+ (nicotinamide adenine dinucleotide) – a chemical that plays an integral role in metabolism.
Recently, Prof Sinclair and his team were able to successfully restore the vision of elderly blind mice suffering from a mouse version of glaucoma in their lab by cellular reprogramming to reinstate youthful function and successfully rejuvenate old cells in the mice’s eyes.
The process used by the scientists – Reviver, which stands for “recovery of information via epigenetic reprogramming” – has shown that old tissues can “keep” a record of youthful epigenetic information that can be accessed for functional age reversal.
“That proves that even a complicated organ like the eye can be repaired, polished and made good as new,” said Prof Sinclair. “We have no reason to suspect it’s any different in a human body.”
Other developments
Prof Sinclair and his team aren’t the only ones making breakthroughs in longevity studies. Here are some other initiatives being made to extend our quality of life
Organ regeneration
American biotechnology company LyGenesis has demonstrated that it can grow functional ectopic organs in patients’ lymph nodes via its organ regeneration technology platform. In other words, there’s a chance that we can get our organs to revert to a normal functioning state should they start to slow or fail.
The company’s co-founder Dr Eric Lagasse first demonstrated that allogeneic hepatocytes – i.e. genetically and immunologically dissimilar liver cells – could re- generate and replace the function of the diseased liver in mice.
The study also showed impressive results in larger mammals, and Dr Lagasse and his team believe the method could ultimately help people with liver diseases. This means that just one organ donor could potentially help multiple liver disease patients.
Brain “rewiring”
The brain has 86 billion neurons, all of which are active. American neurotechnology company Neurolink has been able to record rat brain activity using thousands of tiny electrodes implanted throughout their brains.
Co-founder Elon Musk has also unveiled a pig with a coin-sized computer chip, which he described as “kind of like a Fitbit in your skull with tiny wires”. That might seem like a strange concept, but imagine what the company could do for those suffering from dementia or Parkinson’s disease.
If Neurolink’s trials with humans are successful, then their devices will be used to help paraplegics operate computers or smartphones with just their mind.
Measuring biological age
The epigenetic clock refers to the body’s epigenome, which acts as a “tracker” for changes in DNA (deoxyribonucleic acid) expression. The tracking enables us to identify a person’s biological age, which may be more or less than our chronological age.
Testing for biological age is done by selecting sets of DNA-methylation sites across the genome. University of California, Los Angeles (UCLA), human genetics and biostatistics professor Dr Steve Horvarth has created the most accurate test to date. In time, his breakthrough may be instrumental in helping to show that age reversal may be possible.
Prime editing
We’ve reached a point where the discovery of diseases is often conducted at the genome level and a growing number of studies are finding overlap between “common” and “rare” human diseases. This has enhanced our understanding of how diseases develop and may even bring us closer to a “cure for all and any diseases”.
Now, an advanced form of gene editing is taking another step in that direction. Prime editing can, in theory, allow researchers to edit more types of genetic mutations than current technology.
In addition to correcting genetic mutations in cells that aren’t able to divide, prime editing could also be used to manipulate cells that rarely divide, such as those in the nervous system. In the near future, untreatable neurological diseases like Huntington’s and Parkinson’s may even have a cure.
Tips to stay young
OK, so while all these developments are still in their early stages, how do those of us approaching our golden years try to stay youthful right now? According to Prof Sinclair, the first thing people should do to live longer is to “eat less often”.
“I think the most important thing for increasing healthspan – if there’s just one thing I could say – it would be to eat less often,” he said. “Don’t eat three meals a day.” He also recommended lifting weights, using biomarker feedback, sleeping well and reducing stress, and eating plants that have been stressed.
(Stressed plants are grown without fertilisers or pesticides, and produce their own defensive compounds, thus consuming these plants may also benefit our own biology.) Prof Sinclair also shared about several supplements he considers to be “longevity molecules” or supplements that can help reduce inflammation, help control blood sugar and serve as “fuel” to power sirtuins.
One of them is resveratrol, which contains a natural compound found in red wine that may help lower blood sugar levels and inflammation. The second is metformin, a common diabetes drug (doctors may prescribe it off-label for anti-ageing) that helps to control blood sugar levels, while acting like calorie restriction to protect against health problems and prolong life.
Metformin is derived from a medicinal plant called goat’s rue. It first received attention when a study from the United Kingdom, involving more than 180,000 people, determined that those whose diabetes was treated with the drug lived notably longer than those who didn’t use it.
Newer studies show that it may also have a beneficial effect on heart disease. The third supplement that Prof Sinclair takes is called nicotinamide mononucleotide (NMN), which converts into NAD+ through a series of chemical reactions.
NAD+, in turn, serves as the most important fuel for sirtuin enzymes and to reverse ageing, increase energy production and brain health, and lengthen telomeres, as well as for chromosome stability and immune cell signalling. True longevity (or some may like to call it immortality) is still far away.
But institutions all over the world, from the US to Europe and Russia, are making concerted efforts to achieve this goal, and we may be living in the right time to see these developments come to reality.
By Datuk Dr Nor Ashikin Mokhtar
Published in Star Newspaper, 10 Jan 2022
