Casey Fera asked:
I was trying to think of a way to reverse aging. And I thought about all errors that accumulate in your DNA over the years and I wandered what would happen if you donated blood at an early age and then received transfusions of your own blood when you were older?
I assume there are many things I am over looking like immunity that you acquire when you're older and the fact that when you get a blood transfusion from someone else it obviously doesn't replace your DNA.
But maybe a bone marrow transplant, or some way of infusing DNA without errors or repairing your DNA in someway.
Also I figure there is something I am not considering when it comes to factors such as different localities in the body, I know in Chimerism you can have the body pumping out different sets of genes in different parts of the body.
Thanks, love the show!!!
We put this to I'm Professor Tom Kirkwood at Newcastle University...
Tom - Ageing is complicated. We know that the underlying reason that the body ages is that as we live our lives, our cells accumulate a whole host of small faults, damage affects the DNA, proteins, membranes that make up the cells. So basically, the ageing process is driven by things going wrong, cells become damaged, and that also affects the stem cells of the body. It used to be thought that stem cells could keep going more or less indefinitely, but actually, we know that stem cells that underpin many parts of the body do themselves experience some form of intrinsic ageing.
So, in theory, one might think that a good way to combat some of the effects of ageing would be to replace the cells within the body that had been damaged by this accumulation of faults with cells that are somehow less damaged. And the idea that you could use your own banked cells from earlier in your life is an interesting one. There are problems with that though, ageing affect all the cells and tissues of the body, so simply rejuvenating one particular population of cells maybe do it for that group of cells, but itís not going to do anything about all of the rest. So, itís not going to be a universal effect.
Hannah - Self-bone marrow transplant may not reverse the whole body ageing effect, but it could be used to reverse a specific aspect of it. Bone marrow stem cells replicate throughout your life to produce your blood cells including white blood cells such lymphocytes which act as soldiers, fighting off infection in your body. Your immune system is one function of your body profoundly affected by ageing which is why older people are more likely to succumb to infections. So, could injecting yourself with your younger fresher bone marrow stem cells keep the flu at bay in later years?
Anne - My name is Anne Corcoran. I'm a Research Group Leader at the Babraham Institute in Cambridge and I work on how the body fights infection. Older lymphocytes grow more slowly and make far fewer new antibodies, the proteins that recognise and get rid of infections. So, a younger version of your bone marrow that still has younger stem cells to generate younger lymphocytes might help your immune system to fight infection.
Hannah - In which case, should all under 40s be rushing to have their bones drilled in order to harvest their bone marrow stem cells and bank them to help boost their immune systems later in life?
Anne - Taking a bone marrow sample is not a trivial procedure. Itís not like taking a blood sample. Also, we donít yet know exactly to what effects of long term storage of bone marrow are on its efficiency.
Hannah - Instead, Anne suggests, boosting the older immune system by reducing stress, getting enough sleep, having a healthy diet high in antioxidants, exercise, and some good old physical contact like hugs and handshakes to release endorphins and boost the production of antibodies.
A bone marrow transplant is effective for certain blood-related disease. But for repairing aged, 'broken' DNA a more complex approach is needed. I personally have absolutely no medical knowledge whatsoever, but I did once stay at a Holiday Inn. So my layman response is that it is feasible to reverse cellular DNA damage by delivering replacement/ undamaged genetically compatible DNA to the tens of trillion cells throughout the human body. So to start, yes, it would be helpful to set aside stem cells at a very early age, for example, to cryogenically preserve these cells taken from your own umbilical cord after birth. At later stages in life, this undamaged DNA could be harvested, replicated, then delivered to your body through some sort of vector, such as in viral-mediated gene therapy. I suppose there will eventually be non-viral gene delivery mechanisms developed in the future, such as chemical, mechanical or perhaps using nanotechnology....microscopic delivery bots. kckuhns, Mon, 24th Sep 2012
The most common cell in blood is red blood cells. These have no DNA, do not replicate, and have a very short lifetime in the body, so transfusing these will have minimal benefit. White blood cells are les frequent, and rather specialised, but have a full set of DNA. However, all the blood cells originate in the marrow, so treating the marrow could be a useful therapy for genetic diseases affecting the blood.
Cord Blood, of course, gives a "marrow transplant", rather than just replacing the blood.
I don't think you'd necessarily have to ablate your own bone marrow with radiation before a transplant, Clifford, assuming you were infusing your own cells. The new, youthful, cells would merely take up residence in bone marrow niches alongside their more elderly counterparts... chris, Tue, 2nd Oct 2012
Sorry for the slight change in subject:
If we took ethics aside, imagine the following: MAYBE your young clones could provide all the progenitor cells you need to live healthy ever after. However, the point is: we don't yet know all the pathways for tissue renewal. For instance, Neuroblasts injected to the blood stream would have possibly no effect at all in replacing ageing neurons in the brain or spinal chord. An interesting experimental model would be to promote bone marrow transplants from youngling syngenic mice to elder ones, to evaluate if there would be an immune response improvement to a major ageing related cause of death pathogen infection. Philip, Thu, 30th Apr 2015