Brain banks: Crucial for research, clamouring for donors
Brain banks. The work they do is not widely publicized — most people who consider signing donor cards think along the lines of organs such as the hearts and kidneys for transplant — but it's crucial for many researchers trying to understand the causes and characteristics of myriad diseases.
"Brain donations and brain banks are absolutely essential to neurological and psychiatric research," says Dr. Margaret Fahnestock, professor of neuroscience in the department of psychiatry and behavioural neurosciences at McMaster University in Hamilton.
"One of the main reasons is that there are few to no good cellular or animal models of most neuropsychiatric conditions — schizophrenia and autism, for example," she says. "This is because we currently have a poor understanding of the cellular and molecular basis of most neuropsychiatric disorders."
Fahnestock says that in light of the lack of good experimental models, one of the best ways to make progress in understanding these disorders — and thereby to make progress in prevention or therapy — is to compare the chemistry and structure of normal and abnormal human brains.
"Thus, the generosity of donors of both normal and abnormal brains is critical to our research effort," she says.
Shortage of donors
Brain banks collect brains from donors and distribute tissue to researchers, but finding enough donors is a constant struggle. Traditional organ donation offers people the prospect of saving a life through a transplant; some may be more hesitant to donate their brains because they're only used for research — although this can also save lives by helping researchers find cures for disease.
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Dr. Francine M. Benes is the director of the Harvard Brain Tissue Resource Center, which acquires and distributes high-quality human brains to the research community. Each brain they receive is bisected and one half is frozen and one half is "fixed," which means it is immersed in a fixative solution to preserve it. At any given time, the centre has approximately 2,000 to 3,000 frozen and fixed brains. The centre also has tissue samples embedded in wax for almost all of the cases received since 1980 — approximately 6,000 to 7,000 brains.
Still, the overall number of brains donated each year is many times fewer than other organs, such as heart, lung, kidneys and liver, Benes says.
"I am not aware of any formal databases that document such information, but it is certainly the case that organ procurement organizations place more emphasis on organs and other tissues — e.g. skin, muscle, bone and corneas — because these are used for therapeutic purposes and there is an intense need for such material," she says.
Dr. Naguib Mechawar, director of the Douglas Hospital Research Centre Brain Bank in Montreal, says it's difficult to determine how many brains are donated in Canada each year.
"I'm not sure that such statistics about brain donation exist," he says. "But to give you an idea, we are the only brain bank in Quebec, and 100 brains at most are donated to us each year. We can only accept brains from the province."
Mechawar says that while the figures are low, the number of annual donations has remained fairly stable in recent years. Public awareness of the scientific community's need for donations could be part of the problem — there simply aren't that many brain banks in Canada.
"I get my donations from the States," Fahnestock says. "There is no brain bank in Hamilton. The States has larger, well-established banks. I have obtained samples from a variety of banks — they are usually run by individual researchers or core facilities at educational institutions, such as UC Irvine, University of Maryland, and so on. There are also a few independent banks, such as the Stanley Foundation."
There's also a handful of other banks across the country:
- The Brain Tumour Tissue Bank, located in London, Ont., is funded by the Brain Tumour Foundation of Canada.
- The department of anatomy and neurobiology at Dalhousie Medical School manages the Maritime Brain Tissue Bank; its director is Dr. Sultan Darvesh. (The Geoffrey H. Wood Foundation supports the Maritime Brain Tissue Bank.)
- The Canadian Brain Tissue Bank, founded in 1981, is no longer functioning. It was officially closed in May 25, 2007.
The demand for brain tissue for research is greater than its availability, and researchers studying certain disorders are more likely to receive donated brain tissue, Benes says.
"In our experience, dementia cases — e.g. Alzheimer's disease — are very plentiful, whereas some movement disorders — e.g. Parkinson's disease and Tourette's syndrome — and psychiatric illnesses such as schizophrenia, bipolar disorder and depression, are much more difficult to obtain," she says. "The reasons are complex and vary from one disorder to another."
Brain tissue can help researchers investigate the causes of certain types of behaviour. The McGill Group for Suicide Studies, for example, founded the Quebec Suicide Brain Bank at the Douglas Hospital Research Center primarily to promote studies on the phenomenon of suicide.
Mechawar, who is also an assistant professor at the McGill University department of psychiatry and the McGill Group for Suicide Studies in Montreal, says there is increasing experimental evidence suggesting that there are biochemical, genetic and epigenetic factors that could make people predisposed to suicide.
"Brain donation is invaluable to the scientific community," he says. "Brain tissues help increase scientific and medical knowledge to improve our understanding of nervous system disorders, and enhance our ability to treat, heal and even prevent them."
Researchers can learn a lot from abnormal brains, but they also need normal tissue, he says.
"We do indeed have an important shortage of brains, but it concerns normal brains," Mechawar says. "Studies usually rely on the comparison of diseased versus normal brains, so the latter are very important to obtain as well. But it seems that people that do not suffer from a mental illness are less inclined to donate their brain."
Brain banks also play an important role in research into diseases and conditions that many people don't normally associate with the brain.
"Understanding the chemistry of cells in diseased regions of the brain — what proteins are present, which genes are active — can help scientists determine what went wrong, and develop diagnostic tests and treatments," Benes says. "To identify the chemical calling card of disease, scientists need a supply of fresh brains."
Dr. Elyse Singer, principal investigator and director of the National Neurological AIDS Bank at the University of California, Los Angeles, says her organization's primary goal is to help researchers better understand HIV/AIDS, especially as it affects the brain, spinal cord, and nerves.
The brain itself is only part of the research puzzle in these cases.
"Although they consent to the removal of their brain at death, the strength of the project comes from the information participants provide during life," Singer says.
"Volunteers in the project are given neuropsychological tests, regular medical exams, blood tests, urine screening with optional lumbar puncture for CSF [cerebral spinal fluid] viral load and storage of CSF," she adds. "We build up a detailed picture of the individual's medical history, and then at the time of death, when the brain goes into the brain bank, it provides a powerful resource for scientific research because you've got a really well-characterized group of people. You know their complete medical and neurological status, right up until the time of their death."
Deciding to donate
The subject of whether to donate your brain for scientific research can create a degree of uneasiness for potential participants and their families. To protect privacy, most brain banks identify brains by number rather than the name or other information about the donor.
"At the Douglas Brain Bank, a number is assigned to each brain and the privacy is total," Mechawar says. "This is obviously very important for us. We follow strict guidelines approved by our ethics committee. These guidelines abide to the rules recently published by the FRSQ regarding banks of human tissues."
The banks also maintain tight control over how the brains are used. The tissue cannot be sold and is used solely for research purposes.
"It is illegal to sell human tissues, even for research," Mechawar says. "Tissues are distributed freely to researchers who have obtained ethical approval from their local ethics committee. If a fee is charged, it is solely to cover processing or shipping expenses. The tissues themselves are not sold."
For some, such as Michael Adam Sausser of Santa Monica, Calif., carrying a donor card is a way to contribute something to society. Sausser has AIDS and decided in his 30s that when he dies, he will be a brain donor.
"With the support of my family, who were behind it 100 per cent, I have made arrangements to donate my brain to the AIDS brain bank upon my death," Sausser says. "I cannot donate blood and I am not able to donate my organs. This is a way for me to give back. By becoming a brain donor, it makes me feel like I will live on through the research I can provide."