Stem cells reverse defects in mice embryos

Technique fixes lethal heart problems in womb, scientists say

updated 5:28 p.m. ET Oct. 7, 2004

WASHINGTON - Embryonic stem cells may not have to actually grow replacement body parts to be useful.

New research suggests these cells also secrete healing molecules powerful enough to reverse a lethal birth defect in mice.

Stem cell specialists praised the surprise discovery by scientists at Memorial Sloan-Kettering Cancer Center. The study was reported Thursday in the journal Science.

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The “exciting new study ... expands the potential therapeutic repertoire” of embryonic stem cells, said Dr. Kenneth Chien of the University of California, San Diego.

Embryonic stem cells are master cells that can form into any tissue of the body. Many scientists believe harnessing them might one day allow tissue regeneration to treat numerous diseases.

The Sloan-Kettering experiment suggests an additional role.

Researchers injected stem cells directly into the embryos of mice destined to develop heart defects so severe that the mice would die in the womb. Half the mice were born with healthy hearts.

“We were surprised these (mice) were born and they were normal,” lead researcher Deigo Fraidenraich said.

Yet few of the stem cells actually grew into healthy heart tissue. Instead, the researchers found that the stem cells secreted certain molecules that signaled nearby heart cells to make changes, repairing the defects developing in those tissues. Fraidenraich called the secretions “rescue factors.”

Chien, reviewing the findings in Science, said scientists now should test whether such molecules also might treat adult heart disease.

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