New research helps us come a little closer to reparing damaged hearts after heart attacks
During a heart attack, the flow of oxygen-rich blood to the heart muscle is interrupted by formation of a clot, and downstream heart muscle dies. The scar tissue that replaces the muscle can disturb both the heart’s mechanical action (filling and emptying the chambers) and electrical signaling (which paces the heartbeat). In fact, arrhythmias — heart rhythm disturbances — are a major cause of deaths in patients after a heart attack.
Scientists at UW Medicine have been experimenting with regeneration of heart muscle for a number of years, says Michael A. Laflamme, M.D., Ph.D., UW associate professor of pathology and a member of the Institute for Stem Cell and Regenerative Medicine. They’d already shown that inserting human stem cells into guinea pigs with heart damage improved mechanical function.
In a study published in the Aug. 5, 2012, issue of Nature, Laflamme and Charles E. Murry, M.D., Ph.D., UW professor of pathology, bioengineering and medicine, and co-director of the Institute for Stem Cell and Regenerative Medicine, showed something more. “In this recent paper,” explains LaFlamme, “we show that the transplantation of these cells also reduces the incidence of arrhythmias.”
The human cardiac muscle cells, grown from embryonic stem cells, coupled electrically and contracted in sync with host muscle following their transplantation in guinea pig hearts. “This supports the continued development of human embryonic stem cell-based heart therapies for both mechanical and electrical repair of the heart,” says Laflamme.
— Leila Gray