GAINESVILLE, Fla.---University of Florida researchers, the nation's first to perform an experimental nerve tissue transplant to slow the progression of spinal cord damage in humans, report the condition of a 43-year-old North Florida man has not worsened since the procedure.

The man received the transplant July 11 at Shands at UF.

UF physicians announced the results Saturday (10/25) at the National Neurotrauma Symposium, held in New Orleans in conjunction with the annual Society for Neuroscience meeting. Last Wednesday (10/22), they discharged a second patient, a 50-year-old Central Florida man paralyzed after a motorcycle accident. The man, who underwent the procedure Oct. 10, will continue to recuperate in a rehabilitation hospital.

The experimental treatment involved injecting small pieces of human embryonic spinal cord cells directly into an expanding cavity -- also known as a cyst -- that sometimes forms at the site of a specific type of spinal cord injury. The condition can cause unbearable pain and progressive loss of sensation and movement.

UF neurosurgeon Richard Fessler and his colleagues at the UF Brain Institute performed the procedures to test the safety and feasibility of the grafts, which in landmark laboratory studies have helped injured cats regain some use of their paralyzed limbs. Researchers say the test is an important first step in developing a future treatment that can restore at least partial use of limbs or organs left paralyzed by a crushing spinal cord injury.

"This is very early in our evaluation stage," said Fessler, who performed the transplants. "Our first patient's cyst was very complicated; it was walled off into many small compartments. The areas in which we did not transplant look the same, but the areas in which we did transplant, the cyst did not recur, so we're very encouraged by that."

Magnetic resonance imaging scans show that so far the cavity has not reopened or refilled with fluid in the regions where the tissue transplant was placed, said Dr. Ed Wirth, a research assistant professor in UF's department of neuroscience.

"Even so, we feel it will take at least six months to a year to say for certain whether the transplant has successfully prevented the cavity from refilling and re-expanding," he said.

The second patient's surgery was uneventful, Fessler said.

"He's recovered very rapidly and is doing very well," he said.

Eight more paralyzed volunteers will undergo the procedure as part of a four-year pilot study at UF. The transplant recipients' identities were not disclosed to protect their privacy.

Only patients who have a chronic disorder called syringomyelia, characterized by expansion of a fluid-containing cavity within the damaged spinal cord, are considered for the transplant.

Study participants receive the tissue grafts while undergoing standard surgery, which exposes the spinal cord and drains the fluid-filled cavity through a tube. The spinal shunts, or tubes, often do not permanently halt the cavity's expansion and many patients undergo the treatment repeatedly.

The tissue was obtained from aborted tissue, 6 to 9 weeks old, which otherwise would have been discarded. Researchers said they used such tissue because of its exceptional ability to grow and fill lesion cavities, and because it develops into all of the cell types normally seen in the adult spinal cord. The tissue was obtained from health-care facilities not affiliated with the university.

Doctors will continue to assess the patients' progress every few months, using a battery of tests to rate motor function and sensation, the ability of the spinal cord to transmit information, and level of pain.

Note: This story has been adapted from a news release issued by University Of Florida for journalists and other members of the public. If you wish to quote from any part of this story, please credit University Of Florida as the original source.