A major roadblock to our understanding of autism is our lack of known biological markers for this condition. Biological markers for a condition such as autism can include gene alterations and other measurable biochemical changes in the cells and tissue of those affected. The discovery of such markers is a tremendous boon as they can guide research into the causes and treatments of autism. Indeed, these markers can themselves become targets for interventions.
In the search for autism biological markers, there is an exciting lead in a small duplication of a DNA segment associated with a rare neurodevelopmental condition with similarities to autism. Chromosome 15q duplication syndrome (“dup15q,” for short) demonstrates symptoms similar to that of autism, including developmental delays in speech, language and thinking, as well as challenges in behavior and sensory processing. At present, around 3% to 5% of individuals with autism spectrum disorder (ASD) have dup15q. In other words, they display a “linkage” between these two distinct conditions. By studying the biomarker for dup15q syndrome—that is, the duplicated segment of chromosome 15—researchers can gain key insights into both conditions.
Last month, the Chromosome 15q Duplication Syndrome Advocacy group (IDEAS) (http://www.dup15q.org/) held its annual meeting in Philadelphia. Of particular focus was the frequency with which dup15q patients also experience seizures. This co-diagnosis of epilepsy is of keen interest to autism researchers because the prevalence of epilepsy is likewise elevated among people with autism.
Among the presenters at the conference, Dr. Jerzy Weigel, of the New York State Institute for Basic Research in Developmental Disabilities, discussed neurological structural changes found in dup15q brains. This unique and important research was accomplished through the donation of post-mortem brains of dup15q individuals by the Autism Tissue Program (ATP). By studying brain tissue directly, Dr. Weigel has shown that there are many specific microscopic changes within the brain of these individuals. The next exciting step is for researchers to discover how these tissue changes affect an individual with dup15q and how they may contribute to epilepsy. Such findings can further our understating of not only dup15q syndrome but also autism and epilepsy.
Autism Speaks and the Autism Tissue Program recognize the strong scientific links between autism and autism-associated disorders such as dup15q and epilepsy. As such, your donations (of time, funding, and participation) are supporting efforts to foster promising collaboration between disciplines that, in turn, can increase our understanding of autism and speed the discovery of new avenues for its prevention and treatment. A sincere thanks for your support. We’d love to hear your thoughts.
Fifty years ago, researchers discovered elevated levels of serotonin in the blood of children with autism. What would it mean to our understanding of autism if serotonin—a highly active neurochemical—was also increased in the brain?
In 1961, Schain and Freedman reported that about 40% of autistic children are born with high circulating blood levels of serotonin. This finding has been repeated many times by other researchers. What are the implications? Despite around 600 published research papers looking at autism and serotonin, we’re not really sure. But we’re getting closer to providing answers thanks to crucial help from Autism Speaks.
In the young, developing brain, serotonin stimulates the growth of neurons, or nerve cells. So it follows logically that if serotonin levels are increased in the brains of autistic children, then their brains should be larger. In fact, macrocephaly (big heads) in young children with autism is common. Not only are the brains larger, but certain sensory responses appear earlier in children with autism.
But these findings raise new questions: What do serotonin-producing neurons look like in the brains of children with autism? Would the size and number of serotonin-producing neurons suggest that these cells function earlier in children with autism than in children whose brains develop typically?
The best way to answer such questions is to examine brains of individuals with autism after death. Autism Speaks supports the Autism Tissue Program (ATP), which provides researchers such as myself with access to a the precious resource of brains from autism donors (whose identities are always kept confidential). For instance, ATP records have already confirmed that the brain weights of donors between the ages of 3 and 18 years who had autism are significantly heavier the brains of donors without autism.
To examine the details of serotonin-producing neurons, I and my colleagues prepare and stain slices of brain tissue to reveal the presence of proteins that distinguish serotonin neurons. This procedure allow us to follow how the branches, or axons, of these cells reach out and connect with neighboring cells. Such studies have shown a stark increase in the number of serotonin axons in the brains of children with autism, with these changes appearing in the youngest brains studied (age 3 years) and peaking at around 18 year so of age. Analyses of axon size and branching pattern confirm this increase in an area of the brain associated with auditory sensation and language—the superior temporal cortex. It is hypothesized that the earlier maturation of cortical neurons in this primary auditory area may hinder their incorporation into complex circuits underlying speech.
Of particular interest, my lab has found increased serotonin neuron connections that, on first impression, seem inconsistent with observations widely reported in the scientific literature. Let’s examine them:
First, imaging studies show a decreased rate of serotonin creation and use in the brains of children with autism following administration of tryptophan, a chemical that the body needs to make serotonin. Second, many of the behaviors associated with autism suggest a decrease in serotonin activity. In fact, doctors typically treat hyperactivity, repetitive behavior, and insomnia in adults with drugs that increase serotonin. Paradoxically, recent clinical studies show that drugs that increase serotonin (e.g., selective serotonin re-uptake inhibitors) actually worsen symptoms in children with autism.
The observation that serotonin axons are increased in the brains of people with autism may provide answers to these inconsistencies. Much work needs to done, and the availability of valuable postmortem tissue should be used to its greatest advantage to study not only serotonin neurons, but also other types of brain cells that can affect neurological development. Using the precious resource of donated brain tissue, scientists are able to perform the detailed analyses necessary to see which cells have problems, when and where those problems begin, and what mechanisms may be involved.
Autism Speaks’ Autism Tissue Program supports specialized neuropathology research by providing approved scientists access to the most rare and necessary of resources, post mortem human brain tissue. We wish to recognize the commitment and generosity by our ATP donor families. More information can be found at http://www.autismtissueprogram.org or call 877-333-0999 for information or to initiate a brain donation.
2. Azmitia EC, Singh JS, Whitaker-Azmitia PM. (2011) Increased serotonin axons (immunoreactive to 5-HT transporter) in postmortem brains from young autism donors. Neuropharmacology. 2011 Jun;60(7-8):1347-54.
Jane Pickett, Ph.D., Director of Brain Resources and Data for the Autism Tissue Program
What does autism look like in a brain cell? Since the behaviors that characterize autism are an expression of brain organization and activity, it is logical to investigate this in post-mortem brain tissue’s component cells. This question was a theme at this year’s IMFAR.
The goal of brain cell research is to use information about cell organization, chemistry and genetics to inform and refine therapeutic strategies. One might assume that treatments would be only medications. However, our understanding of the activity of the brain supports behavioral therapy concepts too, especially through the involvement of a brain region known as the cerebellum. Long thought to be only involved in motor coordination, the cerebellum has lit up in functional imaging studies of language, attention and mental imagery. Jerzy Wegiel, Ph.D. at the NY Institute for Basic Research conducted a systematic study of the cerebellum’s smallest and evolutionarily oldest region, the flocculonodular lobe, which has primary connections with the brain’s balance (vestibular) and visual systems. In this region Dr. Weigel sees a disorganization among the neurons and their connections that would certainly contribute to impairment of visual-motor function.
Some of the innovative technology and training programs on display at IMFAR aimed to help children organize their visual and attention systems. Neuroscientists believe that these therapies work by engaging the brain’s remodeling abilities to correct dysfunctional connections between cells. The fact that the flocculonodular lobe is so interconnected with the vestibular system suggests that sensory integration therapies may help coordinate head and trunk movements by re-working connections in this region.
The Weigel lab also reported observing secretions of protein called beta-amyloid in brain tissue of children with autism. Interestingly, the level of beta-amyloid related to the severity of autism and aggression. The amyloid protein is a good example of nature’s multi-tasking. It is a large protein that can be cleaved to smaller active fragments depending on where and when in the brain’s development. This metabolic process may become abnormal when a particular enzyme becomes active. The enzyme is distinct from the enzymes that cleave amyloid into fragments that accumulate outside of cells in the brains of individuals with Alzheimer’s disease, where the protein is more commonly studied.
Epilepsy is a serious problem present in 39% of brain donors with autism. Autism and epilepsy is prevalent in a group of individuals with duplication of segments of chromosome 15. Children have a high rate of sudden unexpected death and the support group, IDEAS, is particularly dedicated to brain donation to the Autism Speaks’ Autism Tissue Program. Dr. Weigel and colleagues have found a broad spectrum of developmental alterations, degenerative neuronal changes and both the overproduction and activation (often a marker of inflammation) of an important brain cell type known as glia. The displacement and activation of glia as well as the appearance of clusters of neurons that appear to be immature or in the wrong place is likely to contribute to high the prevalence of epilepsy in this population.
Eric Courchesne, Ph.D. offered new revelations in brain tissue research in a dramatic keynote address that highlighted the importance of brain tissue for understanding the early abnormal post-natal growth of the brain. His lab observed more neurons in the rapidly developing frontal cortex. A closer examination of the six-layered cortex revealed differences in the unique chemical signatures that mark cells in each layer. In the brains of individuals with autism, Dr. Courchesne found that some patches of cortex do not show the expected markers. Advanced image processing devised by post-doctoral fellow Rich Stoner, Ph.D., generated a stunning three-dimensional picture of the layer, indicating that the cells are, in fact, present yet not displaying their unique signature.
Young investigators in Couchesne’s lab and others are benefitting from brain tissue resources and training in the art and science neuropathology. One such researcher, Ryan Smith, Ph.D. working in Dr. Wolfgang Sadee’s lab at Ohio State University, applied his genetics background to measure the expression of a number of genes related to synapse structure and cell-cell communication in human frontopolar cortex. Robust expression differences were observed for 11 genes between the brains of typical individuals and individuals with autism. For some genes, the genetic factors appear to be rare and only seen in brain samples from individuals with autism suggesting that rare mutations may underlie the autistic phenotype in some cases.
A central feature of the IMFAR conference was the presence of the National Database for Autism Research team leading the NIMH effort to centralize research results and make them available to the broader scientific community. Research results from brain tissue explorations of cell chemistry, cell genetics, cell metabolism, cell organization, cell-cell communication and overall brain structure are being integrated into the national database via the Autism Speaks’ Autism Tissue Program informatics portal.
The organizers of the conference gave special recognition to the parent advocates who launched the Autism Tissue Program and emphasized its ever growing importance in research. They in turn acknowledged the contribution of the families of brain and tissue donors.
We still know very little about the human brain. With an estimated 100 billion neurons (nerve cells) in the human brain, scientists grapple to understand what these neurons do, how they interact with one another and how they make us who we are. It is therefore not surprising that we are still some way from fully understanding the human brain, and more significantly the autistic brain and why its development is altered. There are many scientific approaches that can be used to visually inspect the human brain, such as magnetic resonance imaging (MRI), but only one way of directly studying the human brain – and that is by looking at post-mortem brain tissue. For this very reason, brain tissue is a critical element in the process of neurological scientific discovery. Unfortunately, tissue donation remains rare, hindering the very research that will help us to understand autism.
The Autism Tissue Program (ATP), a Scientific Program of Autism Speaks, is dedicated to supporting scientists worldwide in their efforts to understand autism, autism related disorders and the human brain. The ATP is a tissue based repository (bio-bank), among only a few worldwide, that makes brain tissue available to qualified scientists in order to advance autism research.
In an effort to improve the worldwide availability of tissue-based resources in autism research, Autism Speaks has been seeking to expand its efforts by establishing sister programs in other countries. In 2009, Autism Speaks partnered with UK charity Autistica in creating a 2nd bio-repository based at the University of Oxford in the United Kingdom (UK). There are already 15 brains that have been donated to this tissue bank and, in addition, awareness of the importance of brain donation for autism research within the British autism stakeholder community and general public has increased enormously.
The Medical Research Council (MRC) – the UK’s equivalent of the NIH – has recently formed a network of UK brain banks, including the Oxford autism bank as a key member. This new infrastructure will be a vehicle for facilitating the awareness of the need for autism tissue collection as well as the donation of tissue from controls (individuals who have no underlying neurological or psychiatric disorder) and related neurodevelopmental disorders (e.g. Fragile X syndrome). By encouraging international collaboration and the establishment of a bio-bank network, we can increase the numbers of donations of this precious resource and build the capacity needed for research in this field.
Autism Speaks’ staff recently visited the brain bank in the Netherlands to explore new collaborative opportunities. Due to their geographical size and national organization, the Netherlands have a unique resource in that all brain donations are sent to a single bank based in Amsterdam. This streamlined system enables a higher rate of tissue donations and the administration is relatively straight forward. With the support of the Dutch autism research community and our partners at the Netherlands Autism Society we are hoping that the Netherlands Brain Bank could soon begin collecting autism tissue. Similar opportunities are also being explored in Sweden and Canada.
We are making great strides in scientific discovery and the last few years have seen significant advances in the genetics of autism. More than ever this highlights the importance of using autism tissue collections to explore how genetic differences in people with autism affect the cellular and molecular development of the brain. In turn, these research investments will guide the development of new pharmacological treatments for people with autism to alleviate some of the core and secondary symptoms. With more than 100 research publications resulting from the efforts of Autism Speaks, The Autism Tissue Program, Autistica, and most significantly the brains generously donated by families, we are off to a promising start.
To learn more about brain donation please visit the ATP at www.autismspeaks.org (1-877-333-0999) and UK Brain Bank for Autism & Related Developmental Research at www.brainbankforautism.org.uk (44 0800 089 0707).
This Science post is by staff blogger Jane Pickett, Ph.D.
Researchers have several ways to peer into the human brain. A commonly-used tool is magnetic resonance imaging (MRI) and unlike the two-dimensional pixels in photography, voxels are used to describe the volume of brain measured by MRI. Currently, the standard voxel is a of ~1mm, about the size of coarse sea salt. Combining millions of voxels produces the 3D image of the brain you see in the figure. The view of the brain at this high resolution has led to some common ideas about the ‘autism’ brain.
Cynthia Schumann, Ph.D. and Christine Nordahl, Ph.D. of the MIND Institute at UC Davis, show how imaging, when paired with the microscopic inspection of the post mortem human brain, can help answer questions about typical and disordered brain development. MRI studies of autism have revealed an atypical trajectory of brain growth during early childhood, characterized by brain overgrowth, that is present especially in the frontal cortex (involved in higher mental functions) and also in specific structures such as the amygdala (involved in memory functions, particularly of emotional experiences).
Why are these areas growing larger than normal in young children? One way to answer this question is to look at the cells in these enlarged areas. That solution requires samples of donated postmortem brain tissue.
To give an idea of what’s in a voxel in a typical 3 year old child’s brain: there are an estimated 40,000 neurons in the space of a voxel in the cortex and 7000 in each voxel in the amygdala. The pictures in row C show just a portion of cells in a single voxel in the brain areas indicated. Some evidence indicates that neurons and another cell type called glia are more abundant in the brains of individuals with autism. Connections between cells need space and the more numerous brain cell branching that has been found can also lead to a size increase of a given area.
In addition to counting cells and their connections, fine-scale anatomy allows us to examine the layered organization of cells in the cerebral cortex and other local relationships in different brain areas. When researchers observe cells that are “out of place”, this suggests differences in the functioning of that local network of cells.
Researchers can also use antibodies to localize various molecules in post-mortem brain tissue. With these techniques scientists can identify cells that carry a particular type of neurotransmitter, or other cellular signals. One can also extract and analyze the building blocks for proteins in RNA and DNA and look for regions where a certain gene may have been “turned on” or off more than expected.
Given the coarse resolution of MRI, the field must look towards post-mortem human brain research to help us understand the neurobiological underpinnings of the difference in brain growth patterns that have been found in MRI studies. MRI studies are very helpful in targeting which brain regions should be explored further in post-mortem studies.
Autism Speaks’ Autism Tissue Program supports specialized neuropathology research by providing approved scientists access to the most rare and necessary of resources, post mortem human brain tissue. We wish to recognize the commitment and generosity by our ATP donor families. More information can be found at www.autismtissueprogram.org or call 877-333-0999 for information or to initiate a brain donation.
Brain Research will be publishing a special issue of articles that feature presentations at the 2010 Brain Research meeting. Dr. Schumann’s paper is currently available online with appropriate institutional access or for purchase.
Schumann, CM and CW Nordahl. Bridging the gap between MRI and postmortem research in autism. Brain Res. (2010), doi:10.1016/j.brainres.2010.09.061.
This is a guest post by Kristin and Brian Thompson, supporters of Autism Speaks’ Autism Tissue Program (ATP).
On October 17, 2010 parents and friends of Reid Thompson will be running in the Long Beach Marathon to raise funds and awareness for Autism Speaks’ Autism Tissue Program (ATP). Reid, an 11-year-old boy with autism from Thousand Oaks, CA tragically and unexpectedly died in his sleep in August 2007. “It is our way of honoring Reid’s memory and helping an organization dedicated to autism research,” said Brian Thompson, Reid’s father.
Even though this was a catastrophic loss for the family, the Thompsons courageously made the decision to donate Reid’s brain tissue to the ATP within the critical time period of less than 36 hours after his death. The cause of Reid’s death is unknown as the autopsy results were all normal, with the exception of his brain being slightly heavier than average (this is common among individuals with autism). Although medical experts cannot provide a definitive cause of death, they hypothesize that Reid died from a massive seizure, even though he had no history of seizures.
Reid’s parents continue to seek answers about his untimely death, not only for their own closure, but also to help other families affected by autism. “Reid had autism but we don’t know exactly why his life here with us was cut short,” said Thompson. “Leading scientists are working with the ATP and are already using tissue donated by Reid in hopes of providing our family, friends, and others impacted by autism with the answers we seek. Reid is a teacher and we hope his contribution along with the ground-breaking work being done by the ATP helps scientists understand autism, which will lead to a cure”.
The ATP makes brain tissue available to as many qualified scientists as possible to advance autism research and unravel the mysteries of this and related neurological conditions. In fact, it is the only program solely dedicated to increasing and enhancing the availability of post-mortem brain tissue for basic research in autism. Each precious donation to this program greatly adds to our understanding of the complexities of the human brain and the factors that contribute to autism.
Months after Reid’s passing, Brian met another parent, Ben Fesagaiga, who had just founded an all-volunteer non-profit called Train 4 Autism. Train 4 Autism helps people raise funds for various autism-related charities through participating in athletic events such as 5Ks, 10Ks, half marathons, full marathons, and triathlons. In about three years time, the organization has grown to 35 chapters across the United States and has raised more than $100,000 for autism-related charities.
Team Reid’s Long Beach Marathon participants will include Reid’s father Brian, Brian’s wife Kristin, and Team Captain and Train 4 Autism Director of Communications Molly Rearick, Reid’s former teacher. Team Reid has participated in this event since 2008 and also has a presence at the annual Los Angeles Walk Now For Autism Speaks event in support of Autism Speaks.
To support Team Reid and their efforts at the Long Beach Marathon in 2010, click here.
More information on the ATP can be found at: www.autismtissueprogram.org or by calling (877) 333-0999. The ATP is deeply grateful to the Thompson family for their efforts to advance research into the causes and treatments for autism.
Autism is a clinically diagnosed disorder. Much of our knowledge about autism comes from direct interactions with people diagnosed with autism spectrum disorders (ASD), listening to parents of children on the spectrum, and conducting clinical studies. Magnetic Resonance imaging (MRI) studies have added to our understanding by giving us a peek at the autistic brain and structural differences that may be present. Additionally, strong efforts in genetic analysis have discovered genes of interest and regions within our DNA that may play a part in the development of ASD. Though all these efforts have taught us much about autism, we still know relatively little about the autistic brain and why its development is altered. So how do we learn more?
We must look at things directly.
Consider the following analogy. If you were told to study an office building, but could not go inside, you may find yourself walking around the structure and studying its shape. You could interact with the building by touching the stone and steel that form the building. This would be analogous to clinical and behavioral observations typically made of individuals with autism. Engineering plans, may tell you what the building is comprised of (analogous to genetics studies) and even how it is shaped on the inside—where the rooms are and how stairs, elevators and hallways connect them. This last approach would be analogous to structural MRI studies. Despite the value of each of these perspectives, none of these examinations could reveal the happenings within the building. You would know nothing about the people working within the building, what they were doing, how they interacted with each other and what their jobs may have been.
In a similar way this is how we most often study autism, by looking at the outside, taking an indirect perspective. But there are some scientists who look at things differently. They go inside the building. They study brains directly. And what some of these exceptional scientists have learned so far is quite astounding.
Studying brain tissue directly from deceased individuals, enables researchers to look microscopically at the cells within human brains, how these cells are connected with one another, how they are structured on a molecular level and what that most interesting of molecules – DNA – is doing within the cell. Studying the brain directly allows a far more thorough level of research to be conducted; enabling researches to ask and answer questions that otherwise could not have been addressed, to study the cell and molecular bases behind autism, and granting the ability to look at the fundamental underpinnings behind ASD. Scientists need to study brains from both affected and unaffected individuals in order to make informative comparisons. Without both affected and unaffected individuals to study, the brain tissue loses context and is far less instructive.
Recent breakthroughs in brain tissue research
With brain tissue, scientists can look at the many components needed to make and organize proteins within a cell for proper brain function. Investigators have explored genes that synthesize a major inhibitory transmitter (GABA) in the neural cells and found decreased activity in a special type of protein called an enzyme. In addition, other molecules that detect and bind to GABA (called receptors) are decreased in prevalence in several brain regions. Enzymes and receptors are targets for therapeutics (drug intervention) and are therefore important to understand.
A report investigating 26 brains from the Brain Atlas Project describes some of the atypical findings in the brains of individuals with autism: namely defects in the production, development and organization of new neurons in the brain. Using digital images available to researchers from the Brain Atlas Project, investigators showed that cell populations in the brain, organized in distinct patterns termed minicolumns, are more numerous in the autism brains. Scientists postulate that this increase of minicolumns results in higher sensitivity to stimuli coming into the brain, but at a cost to processing and output in the form of behaviors that characterize autism.
Brain tissue evaluation of mitochrondria reveals differences in these critical cell powerhouses. Mitochondria are responsible for producing most of the energy inside a cell. Brain tissue research has revealed defects in mitochondrial proteins important for shuttling molecules across brain cell membranes. Much like a battery, controlling the flow of molecules within different compartments of a cell is one of the key components to the energy production process and one that appears to be functioning differently in individuals with autism.
Oxytocin is a hormone with a role in social recognition, pair bonding, anxiety, and maternal behaviors. Brain tissue research provides evidence of oxytocin receptor deficiencies resulting in a lower level of effectiveness. This means that even if the hormone is produced normally, it has a reduced effect. Treatments to increase oxytocin functionality in the brain are being explored and brain research will continue to contribute to the understanding of the role of this hormone in the brain.
Scientists also use brain tissue to explore findings from other medical assessments. Analysis of cerebral spinal fluid (CSF) from subjects with autism has shown immune markers of neuroinflammation. Immune activity found in cells from the brain support the concept that specialized brain cells that respond to infection or damage are active in autism brain samples.
How you can help
Unfortunately, brain tissue is exceptionally rare, thereby hindering this rigorous approach to understating autism
The Autism Tissue Program (ATP), a clinical program of Autism Speaks, is dedicated to supporting scientists worldwide in their efforts to understand autism, autism related disorders and the human brain. The ATP makes brain tissue available to as many qualified scientists as possible to advance autism research and unravel the mysteries of this and related neurological conditions. In fact, it is the only program solely dedicated to increasing and enhancing the availability of post-mortem brain tissue for basic research in autism. You can make a profound difference to all those who struggle with autism by registering as a brain tissue donor with the ATP.
A large part about why we, at the ATP, keep working is that when people with autism die, it is sometimes unexpectedly and with little to explain the cause of death. Detailed analysis of the donated tissue helps provide answers as to why death occurred and helps us learn more about these unique individuals in addition to helping researchers understand autism.
If you are the parent of a child or children with an autism spectrum disorder, are related to a person with an autism spectrum disorder, have autism yourself or are unaffected, your donation can greatly affect our progress in understanding autism. We encourage entire families to consider donations of brain tissue for research.
While in some states and countries, registration for organ donation makes the process automatic at the time of death (as on your driver’s license), this is not the case for brain tissue donation. Because brain tissue is used for research and not transplantation, it is not included on most organ donation registries. Therefore, by registering with the ATP, you declare your intent to donate brain tissue as well as making your wishes known to your family in a formalized way. However, registration does not make tissue donation automatic at the time death. This final choice of donation is made by your next-of-kin, which in legal terms, is defined in this order: spouse, adult children, either parent, adult siblings, or guardian at the time of death. Should you choose to become an ATP registrant, and wish to donate your brain upon death, to the ATP in support of autism research, we encourage you to inform others of your wishes, including your immediate and extended family. Helping your friends and family learn more about the ATP and its mission will help them understand your unique choice.
For more information about the ATP and becoming a registered donor, visit our site at www.autismtissue program.org.