Cord Blood Cells Transform Into Heart Muscle
First-time finding showed cells from donor were present in recipient
TUESDAY, Feb. 17, 2004 (HealthDayNews) -- For the first time, scientists have shown that cord blood cells from a donor were present in the failing organs of a recipient.
Cord blood cells are stem cells that come from the umbilical cord blood and placenta after birth. They are used in medicine in much the same way as bone marrow but with a smaller chance of rejection.
In this case, the cord blood cells had actually transformed into heart muscle cells called myocytes.
Although the data does not prove the cord blood cells actually stopped heart damage from progressing, the findings are compelling.
"It gives a correlation that this could be what's happening to help stop the progression," says Kirsten Crapnell, a post-doctoral researcher in the Pediatric Bone Marrow and Stem Cell Transplant Program at Duke University Medical Center. "There have been lots of studies in animal models. They have observed the same phenomenon. This is the first time we've seen it with cord blood in humans."
Crapnell will present the research at the International Association of Bone Marrow Transplantation Research meeting being held this week in Orlando.
The findings have caught the attention of experts.
"It helps the field," says Paul Sanberg, director of the University of South Florida Center for Aging and Brain Repair in Tampa. "That's what we've seen in animals."
The type of research represented here is difficult, if not almost impossible, to do.
Researchers had noticed that, in many children with metabolic disorders, transplants stopped the progression of the damage to the organs.
The boy who was the centerpiece of this study had a disorder called Sanfilippo Syndrome B in which an enzyme needed to break down complex sugars was missing. Without the enzyme, sugar byproducts accumulate in and damage vital organs such as the liver, heart and brain.
The cord blood transplant was intended to help the boy to produce the needed enzyme.
Ironically, the success of the treatment undermines other research. "Because the children are doing so well, we can't biopsy the heart," Crapnell says.
In this case, however, the boy died of an infection so Crapnell was able to dissect and analyze heart tissue. Using a series of stains, she was also able to differentiate between cells that came from the donor and cells that came from the patient.
"There was a sex mismatch. The donor was a female and the patient was male. By using this fluorescent technique, I could distinguish the difference between male and female cells," Crapnell explains. "Then, on top of that stain, I did a surface stain to show that they were indeed myocytes and not blood cells."
A similar process might be happening in the brain, Dr. Jennifer Hall, another Duke researcher who is presenting at the same meeting, says in a statement.
The problem is that it takes time for the transplanted cells to travel to the brain from the bloodstream. If there was a way to begin differentiating the cells into brain cells before delivering them to the organ, there might be a chance to reduce the amount of damage.
Hall found that a type of stem cell (hematopoietic stem cells) appeared able to start differentiating into brain cells called oligodendrocytes in a test tube.
This may potentially aid in the treatment of spinal cord injuries and multiple sclerosis.
The area begs for more research, which could be difficult. "We need to evaluate more children, but we don't want them to die. So luckily there are none to evaluate," Crapnell says.
"It's a big step toward the next step, which is how can you treat these disorders," Sanberg says. "We don't even know if it stopped the damage."
Other groups, including Sanberg's, are investigating whether cord blood can be used to treat heart attacks in animals.
And from there, what's next?
"Experiments are going forward and one can imagine that one day we'll be squirting certain cells into our joints and we won't need joint replacement because the cartilage will regrow. Or we'll squirt cells into coronary arteries that will lodge in the damaged area and will differentiate into muscle cells," says Dr. Richard K. Shadduck, director of the Western Pennsylvania Cancer Institute in Pittsburgh. "It's an exciting area. In essence, it can be thought of as regenerative medicine."
Also presenting findings at the transplantation research meeting is another team of Duke researchers, who have identified immune system differences that make certain children more prone to die of viral infections after cord blood transplants.
The researchers are using their findings to bolster cord blood's ability to mount an effective immune response.