Scientists discover the factor which limits human longevity
You may have seen plenty of talk in the news this week about Hendrikje van Andel-Schipper, the 115-year-old woman who donated her body to science in 2005 - the oldest person ever to do so. Her decision has allowed scientists to make some fascinating discoveries about the physical make-up of healthy human bodies, and the results were recently published in the Genome Research journal.
Blood is constantly replenished by stem cells, which divide themselves to create the different types of blood cell needed by the body. However, errors can occur in this process which cause mutations - such errors are usually the cause of issues such as blood cancer.
There were a number of discoveries made, but the real talking point is that Hendrikje had over 400 mutations in her white blood cells - none of which had caused any kind of disease or health condition during her lifetime. This goes some way to showing that mutations are not inherently bad - usually the only time mutation is studied is when it is linked to a health condition, so the opportunity to study a healthy body containing so many mutations has shown the ways in which the body starts to change as we get older.
The scientists analysed the stem cells responsible, and found that Hendrikje's stem cells had very short telomeres. Telomeres are stretches of DNA which sit on the end of chromosomes, preventing fraying or breaking - a little like the tips of shoelaces. However, as cells divide, these telomeres get shorter, until eventually the cells reach the upper limits of their ability to divide. It's now thought that this is what stem cell exhaustion is what caused Hendrikje's death, and allows researchers to draw conclusions about how genetics and mutations can affect lifespan by changing or affecting the division of cells in the body. Dr. Holstege, lead author of the published study, said that future studies would be needed to determine whether this is a common cause of death in the very old.
If you'd like to donate your body for scientific research, you can do so by following the advice from the Human Tissue Authority.