Cord Blood Stem Cells Treat Fatal Disease

Beat bone marrow for kids with Hurler's syndrome
By Gabe Romain
Betterhumans
May 5, 2004

Umbilical cord-derived stem cells have proven better than adult stem cells for treating a fatal disease characterized by progressive brain and organ damage.

Researchers at the Duke Comprehensive Cancer Center in Durham, North Carolina found that stem cells from cord blood provide an enzyme missing in people with a rare disease called Hurler's syndrome.

"Cord blood stem cells appear to correct the organ damage better than adult bone marrow does," says Duke researcher Joanne Kurtzberg. "The children's cognitive skills continued to improve after transplant to such a degree that they actually gain mental skills faster than age-matched control children and cross over into the normal range at three to four years post transplant."

Enzyme deficiency

Hurler's syndrome is a rare hereditary metabolic disorder caused by a recessive gene that results in the deficiency of an enzyme that breaks down complex carbohydrates.

Symptoms of the disease include dwarfism, mental retardation, decreased joint mobility and respiratory infections.

Bone marrow from adult donors can save some Hurler's patients, but an exact match cannot be found in time for more than 50% of children.

Moreover, adult bone marrow stem cells fail to engraft—take hold and begin to grow—in 28% to 37% of Hurler's patients.

Better than bone

As an alternative treatment, the researchers tested the ability of cord blood stem cells to provide the missing enzyme and thereby halt the progressive organ deterioration in these children.

Cord blood is the remaining blood from a baby's umbilical cord and placenta after birth. The blood is loaded with stem cells, which can regenerate other types of cells in the body.

Because stem cells in cord blood are less mature than adult bone marrow cells, they significantly reduce the likelihood that patients will experience an immune response, in which the body recognizes the cells as foreign and launches an attack.

Such an attack, known as graft-versus-host disease, occurs in 30% to 50% of Hurler's syndrome patients receiving adult bone marrow.

In addition, cord blood stem cells appear to repair more of the damage caused by Hurler's syndrome than do adult bone marrow.

Increased survival rate

In the study, 85% of children who received cord blood survived for two to seven years—the longest period of time they have been followed.

The survival rate among Hurler's children who receive bone marrow is between 63% and 72%.

Cord blood also allowed the researchers to avoid giving children radiation prior to transplant, a toxic regimen that is often necessary to make bone marrow transplants—but not cord blood transplants—successful.

"Cord blood presents an excellent source of stem cells, and it is readily available to nearly every child who needs it," says Kurtzberg. "It provides an important therapeutic option for young patients with severe Hurler's syndrome who lack a perfectly matched and related adult bone marrow donor."

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