No matter how much some would like to avoid this prospect, death is inevitable for all living beings (or is it?). Yet, some people at least live longer than others. A great deal of attention has been drawn to longevity for obvious reasons, but any effort to prolong life needs to start with the very root of the problem – death. So, why do people die of old age? What are the underlying processes? Scientists in Netherlands found invaluable clues as to how our bodies steadily succumb to the inevitable, ultimate end after studying blood and tissue collected from who was once the world’s oldest woman.
World’s oldest woman
There aren’t too many people today who can boast they lived in the IXXth century, but Hendrikje van Andel-Schipper, born in 1890, was one of them. She was the world’s oldest woman, before she unfortunately passed away in 2005, but what’s truly remarkable isn’t the number of days and nights in her life, but how she lived these days – quality vs quantity. Until her very last days, the woman had a crystal clear cognition, according to her doctors and family, and lived a vigorous and independent life. At 115 year, this comes as an astonishing fact.
Sane as she was at her old age and aware of her privileged status, van Andel-Schipper chose to give her body to science, allowing for any necessary measures to study it that might help scientists understand how she reached her centenarian years. The findings suggest that our lives are limited by the capacity for stem cells to keep replenishing tissues day in day out. As these stem cell exhaust their ability to replenish cells, we age and eventually die as this replenishing rate reaches its limit.
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For instance, Dutch researchers found after analyzing van Andel-Schipper’s blood that two-thirds of the white blood cells originated from just two stem cells. When a cell replicates, it has a pattern of mutation which also applies to white blood cells. The pattern was so similar in all cells that the researchers could conclude that they all came from one of two closely related “mother” stem cells.
“It’s estimated that we’re born with around 20,000 blood stem cells, and at any one time, around 1000 are simultaneously active to replenish blood,” says Henne Holstege of the VU University Medical Center in Amsterdam, the Netherlands, who headed the research team.
Considering all these white blood cells came from just two stem cells, it’s safe to assume that most of the stem cells she started out with in life faded away, withered and died. Also, besides stem cell count, telomere length is also of key importance.
Life’s too short
Telomeres have been compared with the plastic tips on shoelaces, because they keep chromosome ends from fraying and sticking to each other, which would destroy or scramble an organism’s genetic information. Yet, each time a cell divides, the telomeres get shorter. When they get too short, the cell can no longer divide; it becomes inactive or “senescent” or it dies. This shortening process is associated with aging, cancer, and a higher risk of death. So telomeres also have been compared with a bomb fuse.
In Andel-Schipper’s case, her white blood cells had drastically worn out telomeres – 17 times shorter than those on brain cells, which hardly replicate at all throughout.
Other important insights came as researchers studied telomeres and stem cells. Invariably, the researchers had to look at cell mutations and this is the first time something like has been performed on a person this old. One reason she grew so old and healthy at the same time, the researchers found, was because of the absence of dangerous mutations. Apparently, van Andel-Schipper had a superior system for repairing or aborting cells with dangerous mutations, and this did wonders for her life.
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So, what can we learn from all of this? Well, first of all the study’s results imply that it may be feasible to inject patients with stem cells collected earlier life, when these are in abundant supply. These stem cells would be substantially free of mutations and have full-length telomeres. “If I took a sample now and gave it back to myself when I’m older, I would have long telomeres again – although it might only be possible with blood, not other tissues,” she says.
In other words, you’d still look just as old, but feel younger and avoid many complications. Still and idea, but my thought is that some researchers will put this into application soon enough. ZME Science is sure to follow any developments.
Findings were reported in the journal Genome Research.
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