Dr. Paul L. McNeils decade-old hypothesis says that when the cell surface is so compromised, calcium ions from outside the cell rush in, prompting membranes inside the cell to fuse and patch the hole.

The cell biologist seems to have proven his theory by taking the red blood cell the one cell in the body known to lack these internal membranes and documenting its inability to self-repair.

By contrast, his work, published in this weeks Proceedings of the National Academy of Sciences, documents the repair process in the simple sea urchin egg and fibroblasts as well as neurons.

Previous work in his lab has shown that skeletal muscle cells which are constantly stretched and strained through normal use, never mind harsh stresses such as distance-running are among the most frequently injured and rapidly repaired of the cells: within 30 seconds they are resealed. The pain and muscle tiredness that comes with exercise likely results from such tearing.

Many of our cells could not survive in the mechanically harsh environment of our bodies if they could not repair, he says. In fact when tearing becomes excessive due to structural defects in the skeletal muscle wall, disease results, such as the crippling Duchennes muscular dystrophy.

He hopes that by understanding the cellular and molecular details of this ongoing repair, he can one day help make it happen.

Its no surprise to Dr. McNeil that red blood cells are injured and dont survive. They constantly bang against blood vessel walls as they deliver oxygen throughout the body. And, its been known for years that these short-lived cells lack the internal membranes that subdivide most cells. The good news is that the bone marrow is constantly producing red blood cells so they dont have to last long.

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Contact: Toni Baker
tbaker@mail.mcg.edu
706-721-4421
Medical College of Georgia
31-Mar-2003