MATRIX RELOADED: Doctors Try New Techniques To Regrow Human Tissue

Five soldiers at a military base in Texas are about to participate in a remarkable test to see if they can regrow portions of fingers they lost in the war in Iraq.

Doctors plan to treat them with a fine powder called extracellular matrix, harvested from pig bladders. The material, found in all animals, is the scaffolding that cells latch onto as they divide and grow into tissue and body parts. In the human body, it was long thought to be inert. But scientists have discovered that it appears to activate latent biological processes that spur healing and regenerate tissue.

Medical researchers have been making intriguing progress in the field of regenerative medicine. The pilot test in Texas shows how doctors are trying to apply their recent discoveries to a pressing challenge: helping thousands of Americans returning from Iraq to recover from wounds that would have killed soldiers a generation ago.

Scientists have long been enthralled by the ability of animals such as salamanders, starfish and deer to regrow body parts lost due to injury or other causes. Cut off...