July 23, 2012
500 Mutations Per Blood Stem Cell By Age 50
You collect about 10 mutations per blood stem cell per year. The accumulation of these mutations leads to a rising incidence of blood cancers (leukemias) as we age. We need youthful replacement stem cells that have very few harmful mutations
AML is a blood cancer that develops when too many immature blood cells crowd out the healthy cells. In recent years, Washington University researchers at the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine have sequenced the genomes of 200 patients with AML to try to understand the mutations at the root of the disease.
Without fail, each patient's leukemia cells held hundreds of mutations, posing a conundrum for scientists, who have long believed that all the mutations in a cancer cell are likely to be important for the disease to progress.
"But we knew all of these mutations couldn't be important," says co-first author Daniel Link, MD, professor of medicine. "It didn't make any sense to us that so many mutations were present in all the cells in the tumor."
To investigate the origin of these mutations, the researchers isolated blood stem cells from healthy people of different ages. The youngest were newborns, and the oldest was in his 70s.
Every person has about 10,000 blood stem cells in their bone marrow, and the researchers found that each stem cell acquires about 10 mutations over the course of a year. By age 50, a person has accumulated nearly 500 mutations in every blood stem cell.
Future stem cell therapies will likely involve first filtering thru many individual cells from around the body to find cells that have no harmful accumulated mutations. Individual cells will be grown into several cells so a cell can be taken and sequenced without loosing a good original cell. The best cell discovered this way will be used to grow cell lines in vitro that will be manipulated for eventual return to the body in large numbers.
If we can replace aged stem cells in the bone marrow and other locations with far less mutated cells then our risk of cancer will decline substantially and the youthful stem cells will divide to produce adult cells that replace lost cells in various organs.
We humans alive today are unprecedentedly fortunate to live in an era of promising technologies such as stem cells.
Life extension has been humanity's deepest desire since times immemorial.
Though we might be fated to be the last generations to live a relatively short life span, at least we can take comfort from the fact that our children will benefit from these technologies and live astonishingly long lives, perhaps for centuries.
That is our deepest desire.
'filtering thru many individual cells from around the body to find cells that have no harmful accumulated mutations.'
I suspect that it will be easier to derive the base sequence (unmutated) and implant/copy it in as many cells as needed. Keep in mind that based on these stats, *every* cell will have mutations - and I bet even with strong AI or other very advanced technology it will be quite a task to look at several hundred different mutations (for each cell!) and say 'these copy errors are harmless, these other ones aren't'. Whereas sequencing several of them (a half dozen should be sufficient) and comparing the sequences to work out the unchanged source sequence is relatively easy.
We can look for the best stem cell in an aged body or.... we can store stem cells while we are young(er). Currently storing blood will run you in thousands of dollars, but it might be a huge business opportunity if you can lower the price, say to $100, and advertise to many people.
Too bad I couldn't have had my umbilical cord blood frozen for banking in 1957. Of course, even if you want to, Obamacare will soon prohibit such "choices".
A new lifelong therapy that will be universally applied by all thinking people, may or may not control aging, and runs the risk of a catastrophic immune response if the unmutated cells are different enough from the mutated ones? Even harmless mutations can change a cell's structure enough that the immune system has to adjust itself to the new cell rather than completely destroying it, especially if it's a fast-dividing stem cell. The more mutations the originals have, the greater the risk of immune response.
Oh, but then we'll just put you on immunosupressants until the new cells take...or we'll start trainig the immune system to recognize these cells through booster shots...or we'll engineer an in vitro alternate immune system that recognizes the cells we're injecting and destroys the old, mutated stem cells...hopefully not too quickly, though...
As a way of keeping biomedical guys employed, I can't fault it. But I highly doubt you'll find enough to do it properly and rigorously for all but the richest and most disciplined of clients. All attempts at temporal immortality, even successful ones, make one's life beholden to the increasingly complicated, rigorous, and comprehensive processes necessary to sustain it. Not to mention being a slave to increasingly complicated life plans whose logic can no longer be reliably followed or executed by those who work for you.
As a culture, we need to move away from the assumption that you can establish any number of half-formed laws, semi-independent institutions, public/private tactical alliances of convenience, and deliberately corrupted corporations on the twin assumptions that those less experienced than us won't waste time taking them seriously and that we'll be alive to either end or fix any problems with them when they crop up. We have enough trouble with kids who act like they'll live forever to deal with adults who "know" they will.
(And who thinks that a man infused with the blood of his youth is going to live sensibly and according to plan? Would he spend his time working in biomed?)
I agree with Dantes. In Australia all umbilical cords are property of the state and used in the construction of giant unbilical mecha that we hold in reserve for the day when the war biobots of the Japanese national health system are unleashed.
those who think they are most free are the ones who are most enslaved! none of the technology in this site will increase human happiness. can a cell phone give you life-long bliss? hence the impoirtance of the hedonisitc imperative website (google it,please.)
"and runs the risk of a catastrophic immune response if the unmutated cells are different enough from the mutated ones?"
Not a problem. Your immune system originally programed itself to leave your own cells alone, it's the mutated cells that are departures from that white listed genotype. I won't say unmutated cells could never be subject to immune attack, as there are auto-immune diseases. But they're the last cells you'd expect to be attacked.