Experimental Transplantation Surgery on TBI Patients

Experiments have been performed in China on eight patients with serious traumatic brain injuries in which brain cells were transplanted into the area of the injured brain. All of the patients had “open” head injuries; that is, the skull was fractured and part of the brain was bulging outside of the skull. Brain cells were removed from each patient during surgery to repair the brain and skull. These cells were then placed in a growth medium where they divided and multiplied until there were approximately five million to 15 million cells.

Because our bodies’ immune systems recognize and attack anything that is “foreign” to the body (such as bacteria and viruses), organs or cells that are removed from another person for transplantation are in danger of being “rejected” by the person receiving the transplant. When cells from the patient’s own brain are used to grow additional cells, the new cells will be recognized as “belonging” to the patient when they are transplanted and won’t be rejected by the patient’s immune system.

The cells that are used to grow new cells are known as stem cells. When stem cells reproduce, they can produce more than one kind of cell. For example, a stem cell in the brain can potentially produce both neurons (the nerve cells that relay information in the brain and spinal cord) and other types of brain cells that support and protect neurons.

The process of growing millions of new brain cells in a laboratory can take one to two months. At that point the patient has a second surgery in which the new cells are surgically placed in the area of injured brain by Dr. Zhu, a neurosurgeon. Dr. Zhu has studied in China, Japan, Germany, and the United States (at Massachusetts General Hospital, a Harvard Medical School affiliated hospital). The surgeries have been performed at Huashan Hospital, a large (over 1300 beds) hospital in Shanghai. Before conducting the experimental surgery on people, Dr. Zhu had conducted extensive experiments on laboratory animals in which cells were transplanted into injured areas of animal brains.

Because the people Dr. Zhu has experimented on had open head injuries, he was able to obtain the brain cells he needed relatively easily and without performing a separate surgery to open their skulls. This has allowed the procedure of obtaining the brain cells to be very low risk (although the various ways in which the skulls were cracked open before the patients arrived at the hospital were decidedly high risk; one of the patients was attacked with chop sticks in a restaurant).

What have been the results to date? Dr. Zhu has not published the results of his research on people (he is publishing his research on animals). With only eight patients who have received the transplants so far, it is difficult to draw any statistically and scientifically sound conclusions. Nevertheless, the hospital has reported that the results have been encouraging. For example, the man attacked with chopsticks was not able to walk following his original hospitalization but did begin walking about a year after he was assaulted.

On the other hand, Dr. Zhu has found that only about five percent of the new cells that are grown are neurons, the type of brain cell that is most crucial for the functions the brain performs. How stem cells are prompted to form one type of cell as opposed to another is the subject of intense research in laboratories throughout the world.