|08-13-2001, 11:38 AM||#1|
Join Date: Jul 2001
Non-embryo stem cells hard at work
Non-embryo stem cells hard at work
By Kathleen O'Dell
Embryo stem cells have grabbed all the attention lately, but their less controversial, equally magic relatives have been quietly performing miracles every day.
Stem cells occur throughout the body in every living human, and they're the source of medical treatments such as lifesaving bone marrow transplants.
Someday they'll have their day in the sun. Scientists have already shown these stem cells hold the key to more tissue repair than once thought. And President Bush, who last week approved funding for limited embryo stem-cell research, also approved federal funds for research into so-called "adult" stem-cell research.
"There are a lot of uses for stem cells that have nothing to do with the use of (embryonic) fetal tissue," said Springfield oncologist Dr. Thomas Froehlich.
"Probably the best example of fetal stem-cell research involves the use of stem cells derived from 'cord blood'" drawn from the umbilical cord of newborns after it has been cut, he said. These are not embryo stem cells.
Cord-blood stem cells can be used to regenerate human bone marrow, he said. That's the spongy material inside bones that makes blood.
On the horizon: Pancreas stem cells may help regrow cells damaged by juvenile diabetes onset, Froehlich said.
Until that and other treatments are available to the public, the tiny, non-celebrities of the stem-cell world continue their daily miracles, giving hope to youngsters such as Springfield 13-year-old Jared Goddard, battling a rare, aggressive cancer called B-cell acute lymphoblastic leukemia. Sixty U.S. children are diagnosed with it every year.
Jared, son of Mark and Cindy Goddard, is recovering from a blood stem-cell transplant at St. Jude Children's Research Hospital in Memphis. Jared is a seventh-grader at Immaculate Conception School in Springfield.
Doctors used blood stem cells derived from Jared's own blood in the transplant.
This "autologous" transplant minimizes the risk that his body would reject blood stem cells from another donor. Doctors "cleaned" the blood of cancerous cells as much as possible before giving it back to Jared.
Cindy Goddard said her fishing, hunting, scuba-loving kid is doing well so far. "He's got a great outlook and he's ready to go home."
Jared still has about three more weeks of recovery in Memphis, and may require a trip to New York for a "mini-transplant" with donor blood stem cells to destroy any remaining cancer cells in his body, she said.
Stem cells are what might be considered "blank slates," or cells that have yet to be assigned a specific job.
They can divide indefinitely and have the ability to become any type of cell to form skin, bones, organs or other body parts.
Blood stem cells give rise to red blood cells, white blood cells and platelets. Skin cells become skin.
Enter: Embryo stem cells, which can be collected during the earliest developmental stages of an embryo, or fertilized human egg.
Scientists consider embryo stem cells the best source of stem cells because they are multitalented - they can spawn almost all types of cells in the body. They don't have specialized jobs such as making blood, skin or bones.
The dilemma unresolved despite Bush's funding restrictions: Harvesting the stem cells destroys the embryo, and many consider that morally wrong.
Researchers think embryo stem cells' ability to become any type of cell makes them perfect for repairing human tissues to treating problems such as Parkinson's and Alzheimer's disease, and spinal cord injuries.
Doctors can already transplant tissue and organ cells, as Froehlich said, but there aren't enough donors. Scientists say embryonic stem cells would enable them to grow any tissue when they need it.
Down the road, Froehlich said, "The hope of many people in this is that at some point in time they can take stem cells and grow a functioning heart and transplant it in someone. But we're a long way from that ever happening. There's a lot of research between here and there."
The stem-cell storm in recent months involves research using embryo stem cells, and the debate rages on.
But researchers are also excited about promising uses of "adult stem cells," those that perform a specific job in the body.
What they're finding is that some stem cells may be more flexible than earlier believed. One example: Studies with rats have shown that stem cells found in the bone marrow were able to produce liver cells.
Here are some of the current and potential uses of stem cells available in sources other than embryos:
•Blood stem cells removed from the umbilical cord of a newborn - after the cord is cut - are used in transplants for some cancers to regenerate human bone marrow. That's the spongy material inside bones that makes healthy blood. Chemotherapy kills off bad and good blood cells in cancer patients, and the transplant can help restore new, healthy blood cells.
•Transplant of bone-producing cells could lessen the severity of osteogenesis imperfecta, or brittle bone disease, in children, according to researchers at St. Jude Children's Research Hospital in Memphis.
•Skin stem cells have been used to grow skin for grafts.
•Pancreas stem cells may help regrow cells damaged by juvenile diabetes.
•In other tests, movement was restored in paralyzed mice and rats by injecting stem cells into the spinal fluid.
•In one of the few stem-cell studies done on humans, some people who failed to benefit from cataract surgery improved when they received corneal stem-cell
|08-13-2001, 11:58 AM||#2|
Join Date: Jul 2001
Location: New Brunswick, NJ, USA
There it is again, the confusion over the use of bone marrow cells that produce blood cells to treat leukemia and auto-immune disease with the use of stem cells to produce neurons and other replacement cells of the body. Wise.