If you’re only 25 years old and you need a new kidney current medical dogma states that you should avoid accepting a kidney from someone who is 85. Why? The answer lies in understanding the influence of shortening telomeres on the lifespan of cells – which is not the focus of this blog. Simply stated, your donated kidney might die before you do.
Humans, and the cells in our bodies, only live a certain number of years before they die. It would be wonderful if we could accept the tissues from other species that live much, much longer than us. Unfortunately, the last member of our Homo genus died out over 50,000 years ago; furthermore, they probably did not have much longer maximum life spans than we do. However, there might be hope – transplants from other species.
Scientists have recently succeeded in transplanting parts of a mouse brain into a rat brain. [February, 2013, Proceedings of the National Academy of Sciences] Amazingly, the mouse brain survived as long as the rats did! Why is this so amazing? Rats live twice as long mice: the mouse brain tissue should have died much, much sooner, but it didn’t. Mice, rats and humans are thought to have genetically determined life spans, meaning that every part of us wears out at about the same time, and then we die. This study suggests that living a long time might not doom us to deteriorating brains and other organs.
Rats evolved about 50 million years later than mice. Apparently, when mouse tissues find themselves living inside of the evolutionarily more advanced rat they take on the characteristic aging pattern of their long-lived host. Scientists now want to find out how we can make this work for humans.
© Gary L. Wenk, Ph.D., author of Your Brain on Food (Oxford Univ Press)