That Aging Thing Again

​If you add it all up, of the 150,000 deaths that happen every day on Earth, over 100,000 of them are caused by aging. Deaths from problems like heart disease are preceded by years of physical decline, loss of independence, and so on. Below (from a BBC article) are the top 10 breakthroughs that prove this idea isn’t science fiction – from the discoveries of the past, to the cutting-edge science of the present day.

Dietary restriction
Researchers are working on ‘dietary restriction mimetic’ drugs, like rapamycin or metformin, which could mimic the effects of eating less, but without the constant hunger pangs.

Negligible senescence
With the appropriate incentives, evolution can equip organisms with mechanisms to repair broken cells and molecules, and get rid of and replace the unfixable. There’s no reason to think that science couldn’t eventually make it possible for humans too.

The hallmarks of aging
After decades of theories and counter-theories, there’s finally some scientific agreement about what causes ageing, and that means, if we can learn to slow, stop or reverse these hallmarks, we can do the same to the ageing process overall.

Telomerase
Inside our cells, our DNA is split into 46 lengths known as chromosomes. At each of these chromosomes’ two ends is a protective region known as a telomere. Your telomeres get shorter over your lifetime, and people with shorter telomeres for their age are at increased risk of diseases of old age and die sooner than people with longer ones.

Rejuvenating the thymus
Just behind your breastbone and in front of your heart is a small organ called your thymus, responsible for production of immune cells. The decline of the thymus is one of the reasons we get more susceptible to infection with age, as shown by older people dying more often from flu, and coronavirus. The good news is, we have multiple ideas to reverse the decline of the thymus, from gene therapies and stem cells to hormones and drugs.

Induced pluripotent stem cells
These cells are made by taking normal body cells and using a cocktail of four different genes to allow them to turn into any kind of cell researchers can dream up – or, hopefully in the not-too-distant future, any kind of cell a doctor needs to replenish cells lost due to accident, injury, or the aging process.
 
The Amish gene 
In the mid-1980s, a girl in the Old Order Amish community in Indiana was rushed to hospital after a minor head injury wouldn’t stop bleeding. She survived, and started a chain of genetic detective work that eventually led to one of the most startling discoveries in the genetics of longevity. Having just one mutated copy doesn’t seem to cause them any blood-clotting issues. However, ongoing back through the Old Order Amish family tree, the researchers discovered something remarkable: people with one copy of mutated SERPINE1 had better heart health, less diabetes, and lived a full 10 years longer than those without.

Epigenetic clocks
Epigenetics is the collective name for a set of chemical flags stuck to our DNA. This is a hot topic of research and has been studied for decades, but what came as a huge surprise to scientists was that observing how your epigenetics change can give us incredibly precise estimates of how old you are.

Intermittent reprogramming
An unexpected side-effect of iPSC research is that those same four genes that can allow a cell to turn into any other kind of cell also turn back its epigenetic clock. The process, known as cellular reprogramming, seems to make cells biologically younger.

Senolytic drugs 
Probably the most exciting breakthrough in aging biology is ‘senolytic’ drugs – drugs that kill aged ‘senescent’ cells. We all accumulate these cells throughout our lives: they’re cells that have divided too many times, accrued unacceptable levels of damage to their DNA, or are just under too high a level of stress. And so, to be on the safe side, these cells stop dividing.


Learn More:

The race to stop ageing: 10 breakthroughs that will help us grow old healthily - BBC Science Focus Magazine