Stem Cells can Regenerate Heart Muscles in Monkeys
A new form of stem cell therapy could potentially repair damaged hearts in the future. According to the study, researchers were able to use human embryonic stem cells to treat monkeys with damaged heart muscles. Researchers believe that human clinical trials could start within four years.
"Before this study, it was not known if it is possible to produce sufficient numbers of these cells and successfully use them to remuscularize damaged hearts in a large animal whose heart size and physiology is similar to that of the human heart," said Dr. Charles Murry, University of Washington professor of pathology and bioengineering, reported by Medical Xpress.
For this study, the researchers headed by Dr. Murry generated a heart attack in anesthetized macaque monkeys by blocking the coronary artery for 90 minutes. Two weeks after, the researchers injected one billion heart muscles cells that were created from human embryonic cells. When the cells entered the damaged heart regions, they were able to regenerate cells that were 10 times greater in volume than other attempts made by other researchers.
After receiving immune system-suppressing drugs, the monkeys' heart muscle cells started to mature. The new cells also started to beat along with the monkeys' heart cells. Within three months, the new cells had fully integrated into the muscles of the heart. The researchers found that on average, the cells were able to regenerate 40 percent of the damaged heart muscle.
Despite the success of the animal trial, the researchers noted that during the weeks after the cell transplants, the monkeys had experienced irregular heartbeats. The irregular heartbeats stopped, however, when the stem cells started to mature.
"The results show we can now produce the number of cells needed for human therapy and get formation of new heart muscle on a scale that is relevant to improving the function of the human heart," study co-author Dr. Michael Laflamme, also from the University of Washington, reported in Philly.
The study, "Human embryonic-stem cell derived cardiomyocytes regenerate non-human primate hearts," was published in Nature.