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Stem Cells May Help Repair Hearts After Attack
Two new studies suggests that implanting tiny scaffolds lined with stem cells may help the body recover after a heart attack – if you're a mouse or a rat, anyway. Whether the results hold true for humans remains to be seen, but researchers are optimistic.
In one study a German team, led by Matthias Siepe at the Medical University Center in Freiburg, wanted to see what effect proteins called cytokines might have in heart attack recovery. Cytokines are proteins that are secreted by immune system cells and affect the function of neighboring cells, so they are used as a way for cells to communicate. Siepe and colleagues used genetically engineered stem cells to find out what affect they might have on the heart following an attack.
They implanted mice with stem cells that produced various types of cytokines. Some mice received the implants on "scaffold"-like structures to support them and others received injections of the stem cells alone. The team found that the groups of mice that received the scaffold-stem cell combo showed marked improvements in their blood pressure as compared to other mice. Certain kinds of stem cells also seemed to reduce damage in the heart tissue itself. The results look promising but more work will have to determine whether the technique will work in humans, too.
A similar study at the University of Washington "seeded" tiny scaffolds with heart cells made from embryonic stem cells. The heart cells were able to grow and multiply around the scaffold and could actually survive a small distance away from it. When the researchers put the scaffold into the heart of a live rat to see whether it would be accepted by the body (and not attacked by the immune system), it was tolerated well – and new blood vessels were actually seen growing into the scaffold.
Lead author Buddy Ratner says in the school's news release, "[t]oday, if you have a heart attack there's nothing that doctors can do to repair the damage...Your body can't make new heart cells, but what if we can deliver vital new cells in that damaged portion of the heart?" And that's just what researchers are beginning to do. Hopefully the results will be just as promising when they are applied to humans.
The first study was presented at the American Heart Association's Basic Cardiovascular Sciences 2010 Scientific Sessions – Technological and Conceptual Advances in Cardiovascular Disease. The second was published in the August 9, 2010 online issue of Proceedings of the National Academy of Sciences.
August 14, 2010
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