Where does aging start?
There is something inside us that makes us frailer as we count more years – in the beginning we will feel more tired, afterwards we may see our first wrinkles and our graying hair. What’s going on? Where does this time bomb start? Which is the first to age: the body as a whole or the cells making it? Do all cells age at the same rate?
I don’t know the answer to these questions, but I do know that elderly people suffer from two things more frequently compared to youngsters:
1. they easily get infected , vaccines don’t work so well on them and they get cancers
2. they easily gain fat
Why is that?
The cells responsible for these functions become senescent and just like some old generals refuse to retire and do a bad job in the first place, senescent immune and adipose cells refuse to die.
Let’s start with the immune system. We have a military budget made of two types of cells: T cells and B cells. We strive to maintain an equilibrium among them, while the budget remains constant. When young, most of our killer T cells are naive ones. They never destroyed foreign substances. As soon as they do, they attack the intruder – whether it’s a foreign microorganism or a cell not recognized as “self” anymore. Out of the colony of killer T cells responsible for destroying THAT type of non-self cell they keep a couple of them, just in case the intruder will enter the body again. If that happens, the immune attack will be much fiercer this time.
But time goes on, more and more such “generals” do their work and then refuse to retire! Not only this, they make life worse for the few T cells which are still naive – the humble soldiers. The military budget is constant, so the body will neither allocate more resources for new naive T cells, nor will it retire and even destroy the non-functional “generals”. The thymus organ is a memory of the past – after the first year of life, the true thymic epithelial space decreases by 3% per year until mid-life and 1% per year till death (source).
As about the adipose tissue, we gain more visceral fat tissue as we count more candles on the birthday cake, while the subcutaneous fat remains all the same – and sometimes decreases.
The bad part about visceral fat is that it causes the following two age-related phenomena:
1. insulin resistance, possibly resistance towards other hormones as well
2. pro-inflammatory signaling shift
(Maybe this would explain why I never saw obese fourth-age patients!)
Ok, this is the problem, now give me the solution!
1. How do we convince these senescent cells to commit apoptosis and retire once and for all?
ApoptoSENS proposes the following:
a) the development of a drug that could kill senescent cells only
Here are some techniques which could be borrowed from oncology – the medical specialty diagnosing and treating cancers:
- the photodynamic therapy
- nanotechnology
- gene therapy – e.g. ganciclovir linked to a promoter that is activated by telomerase only
b) immune system stimulation so that it will better tag and destroy such problem-causing cells just like we do during our adult youth when infections and cancers are rare
2. How do we lose visceral fat once we gained it?
The solution here is less technological because calorie restriction PER SE decreases the quantity of visceral fat tissue. If only our plates would be smaller!
So this is the plan for ApoptoSENS, but that’s not all that needs to be done. While some cells refuse to retire, others refuse to keep dividing– more about it in the next part!
Bibliography:
“Ending aging” by Aubrey de Grey (link)
Anca Ioviţă is the author of Eat Less Live Longer: Your Practical Guide to Calorie Restriction with Optimal Nutrition available on Amazon and several other places. If you enjoyed this article, don’t forget to sign up to receive updates on her second book regarding a comparative biography of aging from the simplest to the most complex organisms known.
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