Autism Tissue Program: the gift of hope. (EP On Autism).
Brain Research of Autism and Related Disorders
The Autism Tissue Program works with families to make rain tissue available to researchers who look for evidence of changes in the brain that explain autistic behaviors and can give clues about useful treatments. The availability of brain specimens in this country is still limited, so the efforts of the Autism Tissue Program focus on educational outreach to families, educators and medical professionals about the importance of brain tissue donation.
Often, the decision is made in the crisis of the sudden death of a young child. By April of 2003, there were 52 donors to the Autism Tissue Program and 26 were under the age of 16; the youngest boy was four. The Program works with advocates in chapters of the Autism Society of America around the country so they are informed about the process of donation and can provide information to others thinking about donation and support for families who go through the process.
We are often asked what researchers expect to find from brain tissue research amid the present confusion about the cause or causes of autism spectrum disorders. The brain is the place to go to understand how the behaviors that we identify with autism--alterations in social interaction and language development, limited interests and unusual repetitive behaviors--come about. The brain is the organ of the body generating these behaviors. Whether caused by a virus, vaccine, environmental toxins, neonatal trauma or innate genetic anomalies, the resulting behaviors we call "autism" occur because the brain is affected.
What We Know
A small number of brains in children and adults with autism have been studied over the last 20 years. In that time, two major groups, headed by Drs. Margaret Bauman and Tom Kemper in Boston and Dr. Tony Bailey in London, looked systematically at the size, shape, location and numbers of cells in various parts of the brain, knowing what the typically-developing brain areas and cells in them should look like. What they found is that many autistic brains are larger in overall size than average and often show "migration" errors so that some cells in the cortex (outer layer) end up in the wrong location. The cortex is where incoming sensory information is processed and where associations, planning and thinking take place. Errors in positioning can lead to miscommunication among brain cells and associated problems in brain functioning. Cortical migration errors in the temporal lobes, which are located on the sides of the brain, are consistent with seizure activity, an important finding since about 30 percent of the donors to our program also had a seizure disorder.
The most consistent brain change found is a decrease in the numbers of Purkinje cells in the cerebellum, which contains over half of the neurons of the brain and appears to play a central regulatory role for the entire brain. An excerpt from a brain-mapping book co-written by an Autism Tissue Program's tissue advisory board member, Dr. John Mazziotta, explains the role of this structure and how damage to the cerebellum might disrupt normal intellectual, emotional and other cognitive abilities. "In the same way that the cerebellum regulates the rate, force, rhythm and accuracy of movements, so may it regulate the speed, capacity, consistency and appropriateness of mental or cognitive processes. The cerebellum is viewed as an oscillation dampener, maintaining function steadily around a homeostatic baseline."
Other brain structures have likewise been investigated in the pioneering brain studies. A system of linked brain areas forms the limbic system, involved in emotional aspects of face processing, in perceiving fear and in the formation of long-term memory. Some brains show increased numbers of seemingly immature cells in limbic structures called the amygdala and hippocampus. These changes, along with some evidence of brainstem structural differences point to problems arising before children are born, early in prenatal development.
The human cortex is structured in mini-columns with cell groups of 60-80 neurons taking in input (information), processing it and generating output (responses). Dr. Manuel Casanova made news with his findings that, in autism cases, these groups of brain cells are smaller and more numerous than average. "Intelligence is not the property of single cells; it's in the circuitry," according to Casanova, and the autistic individual may be "literally bombarded with stimulation from the environment."
An analogy to increased numbers of mini-columns is an increase in pixels in a digital camera. Whether or not this results in higher resolution and can account for observations of exceptional visual memory or special attention to detail often observed in those with autism is too early to tell. Certainly, educators need to understand how the brain is processing information so we can continue to adapt teaching techniques to best support brain function. In contrast to autistic brain tissue, Casanova reported that mini-columns in post-mortem tissue of individuals with Down syndrome were "large and less cell dense, while brain volumes were significantly smaller than the controls."
The Autism Tissue Program employs Magnetic Resonance Imaging (MRI) as a valuable, non-invasive tool for understanding structural abnormalities in the brain. The M.I.N.D. Institute at UC Davis developed a procedure to investigate anatomical differences in the post mortem brain with imaging methods for optimal contrast between gray and white matter. Images of the brain are routinely obtained before distribution of tissue for other research, providing a record of how the brain appeared prior to tissue processing. The virtual representation (Figure 2) of the whole brain can also be subjected to additional analyses such as measuring the volume of brain regions or area of the cortical surface. These images are loaded onto an open site maintained by UC Davis for other researchers (all brain cases are identified by a special case number to protect confidentiality of the donor).
[FIGURE 2 OMITTED]
We want to understand why some brains are large, the developmental pattern in the limbic system and other things. Studies of brain structure aim to detect patterns of developmental abnormalities, to integrate measures of developmental abnormalities and progressive changes with age and to correlate structural differences with clinical features of autism.
Other scientists are studying how autistic brain cells communicate with each other, using antibodies to localize specialized chemicals called neurotransmitters in the tissue. There are a number of different neurotransmitters in the brain. Their production, transportation, release from one cell and reception by another as well as their degradation is all artfully guided by a genetic blueprint and can be disrupted by environmental factors as well as mutations to DNA. Tissue sections can be stained to show which neurochemicals are being made in each cell. Microscopic techniques allow visualization inside of cells and of cell-to-cell contacts, called synapses. Research on specific brain regions or specific neurotransmitters or genes, may eventually lead to new therapeutic treatments.
Genetic material can be taken from the nucleus of single brain cells and analyzed to see which genes were turned "on' or "off" using a method called gene microarray. Cells can also be stained for the presence of genetic messages called messenger RNA. Family genetic and twin studies along with genome-wide linkage studies provide evidence that genetic factors play an important role in autism. It is generally accepted that many susceptibility genes contribute to autism and that environmental factors can influence neural development. Investigators are using special labeling techniques to visualize gene regulatory and signaling factors.
There are currently 30 pilot investigations underway studying tissue donated to the Autism Tissue Program. Each investigation starts as a proposal to the Tissue Advisory Board whose 14 members represent specialization in areas of imaging, diagnosis, cognitive psychology, family and molecular genetics, pharmacogenetics, neurology, epilepsy and neuropathology of neurodevelopmental disorders. Successful applications are those that ask important questions to clarify what is happening in the brain; then tissue is allocated and research progress is tracked. Data is maintained in a format consistent with broader efforts from the National Institute of Health (NIH) Human Brain Project.
Brain Donation: What Happens
Brain recovery needs to take place within 24 hours of death to preserve tissue for study. The usual procedure is for the family to contact the brain bank by calling the Autism Tissue Program and providing information about the donor and location of the hospital or funeral home. A local pathologist or specialist will coordinate the recovery procedure so that normal funeral preparations, including viewing, can be made. The Autism Tissue Program assumes the costs associated with brain removal and transportation to the bank.
A popular misconception about brain donation is that being a registered organ and tissue donor automatically ensures that brain donation will occur. Most organ donation organizations groups do not recover brain tissue for research. However, a new pilot program may help make brain donation easier for families in the future. A unique collaboration exists between the Autism Society of Iowa and the Iowa Donor Network as a result of a grant from the National Alliance for Autism Research (NAAR). Working together on common goals, the state autism society has alerted its members about the importance of organ and tissue donation and encourages registration with the Iowa Donor Network for this purpose. The Network, in turn, has added "brain tissue for research" as an option for registrants. This means that donor family services in Iowa will help families through the process of brain donation as well as explain options for donation of life-saving organs and tissues.
The variability between individuals with autism and various research possibilities means that investigators need an adequate archive of brain tissue from donors of all ages, from relatives of those with autism, and from those without autism for comparative studies.
Ric McNally, President of the Autism Society of Michigan, speaks of his family's experience after their decision to make a brain donation from his brother, Scott, when he explains, "Unexpected death is a tragedy, but organ donation and Autism Tissue Program participation allow us the comfort of knowing that the loss of a loved one is tempered by a gift to others."
The Autism Tissue Program is supported by three partner organizations; the Autism Society of America Foundation, the M.I.N.D. (Medical Investigation of Neurodevelopmental Disorders) Institute at UC Davis and the National Alliance for Autism Research (NAAR). The Program is the recipient of a supplemental grant to the Harvard Brain and Tissue Resource Center by the National Institute of Mental Health and the National Institute for Neurological Disorders and Stroke.
If you would like information about the Autism Tissue Program and research programs, or wish to register, you can call 1-877-333-0999 or write the Autism Tissue Program at 99 Wall Street, Princeton, New Jersey, 08540, or email email@example.com or obtain information or register online at www.MemoriesofHope.org. Clinicians and researchers are encouraged to send for packets of materials about the Autism Tissue Program to distribute to groups.
Jane Pickett, Ph.D is the Director of the Autism Tissue Program.
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|Publication:||The Exceptional Parent|
|Date:||Jun 1, 2003|
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