Inflammation Process Discovered

Researchers at the Massachusetts General Hospital (MGH) have discovered the process by which the body finds and rids itself of damaged tissue.

The finding opens new avenues in the search for drugs which can combat acute inflammatory conditions like arthritis, said Dr. M. Amin Arnaout, the study's principal researcher.

The results, published in today's issue of the journal Cell, describe how the body activates infection-fighting cells called neutrophils that find and destroy damaged tissue.

By targeting specific parts of the molecule for mutation and observing the results, Arnout and other researchers were able to pinpoint the position of the neutrophil receptor sites. They also found the key amino acid sequences which determine the neutrophil receptor structure.

"Now that a target is identified," Arnaout said, drug companies can begin to develop "safe and effective therapeutics" to combat inflammations. Such drugs could prevent neutrophils from being "turned on" and inflaming an injury by blocking receptor sites, he said.

Damaged or oxygen deficient tissue in persons suffering from traumatic injuries or receiving organ transplants release chemicals that "activate" the neutrophils by binding to their receptor sites.

The activated neutrophils then "walk across the epithelium into damaged cells," where they digest the useless tissue, Arnaout said.

This digestion of damaged tissue by neutrophils produces the familiar inflammation associated with many types of injuries, Arnaout said.

But neutrophils can often malfunction and attack healthy tissue, he said. When this happens, drugs are needed to "turn off" these uncontrolled molecules.