August 28, 2004
BehindTheMedspeak: Prenatal diagnosis, stem cells, and a new, paradigm-shattering discovery
Dr. Diana Bianchi, chief of the division of medical genetics at Tufts New England Medical Center in Boston, is the lead scientist behind a revolutionary development.
Dr. Bianchi's original area of research was prenatal diagnosis.
She knew that a few fetal cells enter a woman's blood during pregnancy and hoped to extract those cells for prenatal diagnosis.
With polymerase chain reaction (PCR) technology, only a few cells are required for DNA amplification and production of enough material for genetic analysis.
Years of work by her laboratory to isolate those few circulating fetal cells from the maternal bloodstream were unsuccessful; such fetal cells are so scarce that even today's cutting-edge technologies were unable to identify them.
But then Dr. Bianchi made the first of her unexpected discoveries: fetal cells do not disappear when a pregnancy ends.
Instead, they remain in a woman's body for decades, perhaps indefinitely.
If a woman's tissues or organs are injured, fetal cells from her baby migrate there, divide and turn into the needed cell type, be it thyroid or liver, intestine or gallbladder, cervix or spleen.
She and her research group find fetal cells by looking for male cells in tissues and organs of women who have been pregnant with boys and showing that the cells' DNA matches that of the women's sons or, if the women had abortions, their male fetuses.
Cells from female fetuses also enter a woman's body, but it is quicker and easier to find the male cells by looking for cells with a Y chromosome.
One woman, for example, had hepatitis C. But when her liver repaired itself, it used cells that were not her own.
"Her entire liver was repopulated with male cells," Dr. Bianchi said.
Such findings astonished not only Dr. Bianchi but others in her field, who looked askance at such unanticipated results.
Now, with publications in leading journals including last month's Journal of the American Medical Association, few doubt her.
In theory, fetal cells lurking in a woman's body are the equivalent of a new source of stem cells and could be stimulated to treat diseases.
However, Dr. Bianchi says that she does not yet know for sure that the cells are stem cells - she must isolate them and prove they can turn into any of the body's specialized cells - nor where the cells reside, or how, short of injury, to spur them into action. [via Gina Kolata in the New York Times]
The implications of Dr. Bianchi's work are stupendous.
•If women who've been pregnant automatically create a long-lived collection of potential stem cells from each pregnancy's embryo, every woman has the potential to regrow and repair herself and theoretically live forever.
The whole uproar about cloning and stem cells disappears; it's a non-issue.
•Each woman carries, somewhere within her body, a source of stem cells for each of her offspring, no matter how old or which sex they are.
Not only can such stem cells take part in repairing a woman's own body, as Dr. Bianchi has already conclusively demonstrated; theoretically, these cells could provide such material for each of her children in the event of illness or injury.
•Within each paper cut or scrape on a woman's body are cells from each of her previous pregnancies. It becomes possible to quantify how many there have been, as well as the sex of each.
"Have you ever been pregnant? Had an abortion? No? Well, we'll just confirm that."
•I believe we are witnessing the beginning of an entirely new branch of science, which others have termed regenerative medicine.
Most people know that salamanders can regenerate their legs.
Not as well appreciated is that children up to the age of 11 can regenerate fingertips.
It's time for the rest of us to join the party.
August 28, 2004 at 09:01 AM | Permalink
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» Giving Birth: Doubly Life-Giving? from Amy Ridenour's National Center Blog
Women who have been through pregnancy tend to say pregnancy is not always easy, but that it is very much worth it for the child's sake. [Read More]
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