Brain Transplants

By William K. Summers, MD
© 2000-William K. Summers, MD

In medical school, I was taught many funny notions and myths. One example was alcohol and brain injury. If you were stupid enough to drink alcohol, 10,000 nerve cells died with each shot of whiskey. Now, there are over 2.6 billion nerve cells in the human cortex (the thinking brain). To kill half of a person's cortex, one would have to drink 103 million shots of whiskey. Drinking sixteen shots of whisky (one per hour) per day, it would take 18,082 years for a person to kill half of their cortex. Most of us will not live eighteen thousand years! It bothers me when my colleagues promote wild numbers and myths to scare people.

Another myth was the notion of brain permanence. By this myth, there is one set of brain cells you inherit by the age of three. This means your IQ is fixed by age three. This means if you have head trauma or a stroke, the damage is permanent. If injured, the brain could not, like the liver, regenerate up to 50% of itself. Yes, blood cells totally replace them selves inside a month, but not the brain. This notion of permanence never made sense to me.

In the 1970's, theoretical neuroscientists explored the concept of nerve cell "plasticity". This means the same old neuron can be retooled to do new things. For example, a "playing on the swing with mother" memory may lie in a 10,000 cell block of the brain. Years later the brain would use part of these cells, say 5000, to lay down another memory. While both memories co-exist, they are fuzzy. This was used to explain how stroke victims partially recovered from severe paralysis. The "plasticity" theory did hold that the nerve cells could physically accommodate new tasks. The brain permanence theory was being challenged.

In 1987, a courageous Mexican neurosurgeon implanted stem cells (baby nerve cells) into specific brain area of a few Parkinson's patients. The scientific community called him a fraud. They could not replicate his findings. Of course, they did not replicate his technique, so the possibility of replicating his findings never existed. Soon the neurosurgeon had been sullied and forgotten. Now, the concept of brain transplantation is being re-discovered.

In June, 1998, doctors from the University of Pittsburgh transplanted embryonic nerve cells into a stroke patient. They have since transplanted twelve patients. It is too early to fully evaluate. However, several of the stroke victims are showing better functioning than would be expected. The study needs to be expanded to about 100 patients. The origin of the nerve stem cells was a cancer found in the lung of a patient in 1978. Thus, it needs to be certain that the transplants do not become cancerous. Because all of the transplants to date come from this one source, a way to increase the supply needs to be developed. Layton BioScience Inc. has been working on this issue since formation in 1991. Layton BioScience was instrumental in the work at Pittsburgh.

The technology and the possibilities are promising. Already, plans are being made to use stem cells in Parkinson's disease and spinal cord injury. This means there is hope for Alzheimer's and other dementing illnesses. Please understand, I do not recommend drinking excessive alcohol. Nevertheless I note there is hope for a number of brain diseases--based on truth rather than myth. Next time I will talk about Brain Regeneration.

To your health.