A new study reveals that oxygen is the trigger that helps specific genes in heart cells called cardiac fibroblasts transform these cells into myofibroblasts cells that are critical to wound healing after a heart attack. Scientists believe these newly formed myofibroblasts help new tissue grow, replacing tissue damaged by the attack.

The first step in treating a heart attack survivor is to quickly remove the clot blocking a coronary artery which caused the attack. This allows a sudden rush of oxygen-rich blood to flow into damaged tissue around the site of the primary injury.

The rush of oxygen activates oxygen-sensitive genes in cardiac fibroblasts, and these genes respond by turning cardiac fibroblasts into myofibroblasts, said Chandan Sen, the study's lead author. Sen is the associate director of the Dorothy M. Davis Heart and Lung Research Institute at Ohio State

"Now that we've identified the mechanism in this band of cells, we may be able to develop therapies that target these healing cells, thus enhancing their ability to replace the tissue damaged during a heart attack."

The study currently appears online in the Journal of Biological Chemistry.

The researchers exposed fibroblasts taken from mouse hearts to a sudden rush of oxygen, a situation that mimics suddenly exposing heart tissue with a poor blood supply to more oxygen once a clot has been removed.

The sudden rush of oxygen transformed mouse heart fibroblasts into myofibroblasts.

"Myofibroblasts go to work after you cut yourself," Sen explained. "They have muscle-like properties and try to contract and close a wound. These are robust cells -- they remain at the damaged site even when all of the heart muscle cells have died.

"Other scientists have detected an abundance of myofibroblasts in heart tissue after
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Contact: Chandan Sen
Sen-1@medctr.osu.edu
614-247-7786
Ohio State University
15-Sep-2003