There are some scientists, such as Aubrey DuGrey, who firmly believe that there are humans on this planet today who will never die thanks to anticipated advancements in science. Some days, I think he may be right. For better or worse...
For decades, scientists have sought to understand the anti-ageing effects of "parabiosis," in which researchers sew a young mouse and an old mouse together so that they share a circulatory system. As ghoulish as the research may sound, experts said that it could lead to treatments for disorders like Alzheimer’s disease and heart disease: the blood of young mouse’s blood seems to rejuvenate the old mouse, regenerating its wasting muscles and restoring its cognitive abilities.
(On the basis of those results, at least one company - based in South Korea - is attempting to replicate the effect in humans using blood plasma from healthy young people to treat patients with Alzheimer’s disease.)
When these results were first observed back in the 50s, scientists could not say how the transformations happened. There was not enough known at the time about how the body rejuvenates itself.
It later became clear that stem cells are essential for keeping tissues vital. When tissues are damaged, stem cells move in and produce new cells to replace the dying ones. As people get older, their stem cells gradually falter.
In the early 2000s, scientists realized that stem cells were not dying off in aging tissues. “There were plenty of stem cells there,” recalled Thomas A. Rando, study author and professor of neurology at Stanford University School of Medicine. “They just don’t get the right signals.”
In November of 2016, it was found that blood from human teenagers(!) can rejuvenate memory and cognition in elderly mice, probably due to factors present in the plasma – the liquid portion of the blood.
A new study now shows that blood harvested from babies’ umbilical cords has been found to have even stronger anti-ageing effects than blood from older humans...
[Blood plasma from people at three different life stages – babies, young people (~age 22), and older people (~66) was injected into mice that were the equivalent of around 50 years old in human years. The most dramatic effects occurred when these mice received babies’ cord plasma. They became faster learners and were better at remembering their way through a maze. This corresponded with enhanced activity in their hippocampi – the brain regions responsible for learning and memory.]
Mice that received young people’s plasma also had modest improvements in hippocampus function, but those that received plasma from older adults showed no such improvement. This suggests that human plasma gradually loses its rejuvenating potential with age.
The researchers found that a protein called TIMP2 may be responsible for the effect. TIMP2 declines with age and is known to inhibit a group enzymes called matrix metalloproteinases, some of which are involved in the progression of Alzheimer’s disease. (These enzymes modify the 'extracellular matrix', the proteinacious 'web' that surrounds cells and can instruct their fate, motility, etc.)
TIMP2 may have potential as a treatment for age-related cognitive decline and Alzheimer’s disease. Using TIMP2 as a treatment would be better than using cord plasma itself because it can be synthesised in a lab, avoiding the need for donor supplies. HOWEVER, first, we need to understand a lot more about how it affects the brain and that's not easy. We have a long way to go before it has any therapeutic potential.
Several teams are already experimenting with blood plasma. A trial is under way at a hospital in South Korea to test whether injections of human umbilical cord plasma have anti-ageing effects in healthy people aged 55+. (Results due in August.)
The caveat here is that we would need to take extreme caution in rejuvenating old body parts: waking up stem cells might lead to their multiplying uncontrollably and it's quite possible that it would dramatically increase the incidence of cancer.
Of course, this whole thing raises interesting thoughts and ethical questions on life span. With this biotechnology, along with robotics, could we live to a healthy 300 years old? Would we want to? Should we? I'm not so sure... For now, it's an interesting thought experiment.