Purdue News

January 8, 1993 Purdue Researchers Transplant Neurons Into Rats' Spines WEST LAFAYETTE, IND. – Purdue University researchers may have discovered a viable source of replacing adult nerve cells lost after injury to the spinal cords of rats. Christine B. Jaeger (YAY-gher) and Richard B. Borgens of the Purdue Center for Paralysis Research say they believe they are the first to successfully graft mature intestinal neurons in mammals, placing the cells into spinal cords of adult rats. "It's very exciting to have discovered a new source of regenerating neurons in mammals," says Jaeger, associate professor of veterinary anatomy. "What we've done is take mature, differentiated nerve cells from one part of an adult mammal, move them to another part of the body and have the cells survive. "While we still have a long way to go, the results lead us to hope that doctors might one day be able to move healthy cells from a human patient's intestines to the spinal cord or brain, where the cells might grow and help heal the injury." The results of the study appeared in the Dec. 14 issue of Neuroscience. An estimated 250,000 persons in the United States have severe spinal cord injuries, according to the National Institute on Disability and Rehabilitation Research. About 9,000 to 12,000 new cases are reported each year. Persons are disabled not only by the death of spinal cord nerves but also by the breaking of the transmission process of the surviving neurons, says Borgens, professor of developmental anatomy. Borgens says the research addresses a fundamental problem in trauma to the brain and spinal cord. "Essentially, adult mammals in general don't have the capability to replenish neurons except for those in the intestines and the lining of the nose," says Borgens, director of the Center for Paralysis Research, which is part of the School of Veterinary Medicine. "Those intestinal and olfactory neurons might someday be a source of new nerve cells in the damaged spinal cord and brain." Jaeger says, "The nerves' ability to survive and grow needed to be investigated first. Later we can determine if the nerves have some plasticity or can function as needed in their new environment." If nerve cells could be transplanted successfully in humans, people with spinal injuries or brain damage such as from strokes or Parkinson's could donate their own tissue to these damaged areas, says Jaeger. That would avoid foreign-tissue rejection, the need for drugs to suppress a patient’s immune system, and the ethical dilemma of using fetal-tissue transplants, she says. Borgens, Jaeger and Dr. James P. Toombs of Purdue's Department of Veterinary Clinical Sciences took tiny clusters of neurons embedded in smooth muscle and connective tissue of intestines from four adult rats and grafted the bundles into the spinal cords of 20 other rats. Each of the clusters was about the size of a grain of salt. When the researchers checked some of the grafts after two weeks and different grafts after two months, they found that fibers from the transplanted neurons were growing in length, although the nerve cells were not increasing in number. "At this point, we know that the neurons survived and grew for a relatively short period of time when transplanted from one rat to the next," Jaeger says. "We're repeating the experiment but taking intestinal tissue from rats and grafting it into their own spinal cords to see if an individual can be its own donor and if the transplanted nerves will survive indefinitely." The study was funded in part by the Canadian Spinal Research Organization and the U.S. Department of Defense. Purdue News Service: (765) 494-2096; purduenews@purdue.edu