Placentas might be key to brain therapy

Researchers may have discovered a cheap, plentiful supply of human transplant cells for the treatment of brain damage after stroke or injury.

Use of cells recovered from the placenta and umbilical cord after birth would not raise the difficult ethical issues associated with using embryos or foetal cells recovered after abortions.

Advances in reversing brain damage were discussed during a session on "Reprogramming the Human Brain After Injury" at the American Association for the Advancement of Science meeting in San Francisco.

"We are on the cusp of a new beginning," stated Prof Sandra Chapman of the University of Texas, Dallas. "Once thought to be science fiction, we are now finding that the brain, that black box, has great potential for repair."

Prof Paul Sanberg, director of the Centre for Ageing and Brain Repair at the University of South Florida, described a range of transplantation therapies in promoting brain repair. Foetal cells recovered from abortions had been shown to integrate into the brain and appeared to improve the condition of patients suffering from Huntington's disease.

There were ethical issues associated with the use of these cells, however, and they were not plentiful, Prof Sanberg said.

Other cells used for brain transplants included cells from bone marrow, embryos, and sertoli cells from the testicles.

A promising new approach involved the use of blood cells taken from the umbilical cord and placenta, Prof Sanberg said. "It is an abundant source of supply for neuronal transplantation," he said. This material was usually discarded after a birth, and because no foetal cells were involved, ethical issues were not a problem.

There were actual advantages to the approach, he said. It was non-invasive and the rejection issue was less of a problem because the cells had only a low level of immunological activity.

The cells must be treated to "reprogramme" them, which prevents them from becoming other types of cells. They could also be given to the patient by intravenous injection rather than direct injection into the brain, Prof Sanberg said.

Tests have been carried out on rats. The cord cells were shown to migrate towards the site of brain damage, where they changed to become new brain cells. The research group found that the best results came when the cells were provided within 24 hours after injury. "They demonstrated recovery in seven to 14 days and had improvement by as much as 50 per cent," Prof Sanberg said. "There was an accelerated recovery."

Human clinical trials could begin within one or two years, he said. While the approach shows promise, much remains to be done to confirm that it will benefit human patients.