Researchers are taking the very first steps in restoring electrical conduction in the ailing heart.
About one out of 22,000 children is born with serious flaw in the heart: The self-generated electrical impulse in the right atrium of the upper heart fails to reach the lower ventricles, preventing them from being stimulated to pump out blood after filling up. In adults, the same problem can occur after a heart attack that injures a circuit connecting the upper and lower heart. A team of investigators has now carried out a 6-year study showing that, at least in rodents, a bridged circuit can be made from the body's own cells to electrically reconnect the bad wiring.
To make the patch, cell biologist Douglas Cowan of Children's Hospital Boston started with muscle precursor cells called myoblasts, which are usually found in skeletal muscle and conduct electrical signals. Cowan's team isolated the cells from rat skeletal muscles and grew them on plates. After a day, the researchers fashioned a 3-dimensional segment of tissue made of collagen and seeded it with the myoblasts.
Then the team implanted the structure into rats to electrically connect the upper and lower heart. It worked. Electrophysiological studies revealed evidence of what appeared to be permanent conduction across the implant in one third of the implanted animals, the team reports online today in the American Journal of Pathology. Cowan's team is now trying the therapy in lambs.
The findings are encouraging, says University of Pittsburg cardiac surgeon Amit Patel, especially if they can be replicated in large animals.
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