What's going on in Spinal Cord Research here in Australia?
What's going on in Spinal Cord Research here in Australia?
Recently I have been asked so many questions about how spinal cord research is going, so I thought I would do a bit of research. I have scoured the country talking to the scientists and asking them to contribute some information about their work. This article below outlines the work of some of Australia's top scientific researchers. Bare in mind, not every piece of research is working exactly on spinal cord research, however, in the long run all of this research is inter-related and who knows who might come across the technology that will allow the relief of not only spinal cord patients but many other related ailments. Let's hope that one-day we can all dance and celebrate together.
Gary Allsop (Honorary Director, The Australasian Spinal Research Trust)
Professor Perry Bartlett and his team at the Walter and Eliza Hall Institute
Repairing the damaged Nervous System by Activating Resident Stem Cells in the Nervous System to make New Nerve Cells.
The aim: To discover drugs which can stimulate stem cells, resident in the brain and spinal cord, to make new nerves to replace those lost in Head and Spinal cord injury and neurological diseases such Motor Neuron Disease (ALS), Parkinson's, Alzheimer's. This is distinct from transplanting stem cells, which requires surgery and anti-rejection therapy, and as yet no evidence of success in treating neurological diseases.
Discovery of Brain and Spinal Cord Stem Cells
There has been no greater paradigm shift in the Neurosciences over the last 100 years than has occurred as a result of the discovery of stem cells in the adult mammalian brain and their ability to make new nerve cells. The shift from the concept of static, non-renewable brain, to a brain with the capacity to continually replace and renew nerve cells has occurred as a result of discoveries over the past 10 years. In 1992 two groups, Bartlett's group in Australia and Weiss's group in Canada showed for the first time that there were cells (stem cells) in the brains and spinal cord of adult animals capable of making new nerve cells. This discovery marks the turning point in our concept of the brain's self renewing properties and opened up the possibility of harnessing this ability to repair nerve cells lost in Head and Spinal cord injury and in diseases such as Motor Neuron Disease (ALS), Parkinson's, Alzheimer's, Stroke.
Brain Stem Cells Are Making New Nerve Cells Everyday:
Since the 1992 discovery, many groups have shown that stem cells in the brain (they are found throughout the nervous system) of all mammals, including humans, continually produce neurons in the olfactory bulb (smell centre) and the hippocampus (organ responsible for short term memory). More remarkably, they have also shown that the production of new neurons may be central to vital brain functions such as short-term memory formation.
Brain Stem Cells can Replace Damaged Nerve Cells
Resident stem cells have also been shown to produce new neurons in response to damage and, most importantly, that the new nerves integrate into functional networks. Thus, over the last 10 years the stem cells resident in adult mammalian brain have assumed central importance in the maintenance of brain function and in the area of brain repair. This latter concept brings with it the burgeoning interest in discovering protocols to stimulate the endogenous stem cell to replace neurons lost or damaged in disease processes.
Harnessing this capability: The Significance of Finding the Brain and Spinal Cord Stem Cell
The aim of developing drugs to stimulate the production of new nerve has been critically hampered by the inability to identify and isolate the brain stem cell. This is why Bartlett's Group recent discovery was of such importance. The importance of the discovery was recognized, by being published on the front cover of the most prestigious science journal Nature in August 2001. Bartlett's group has successfully isolated the stem cell from the adult brain and examined its properties directly. In this hallmark paper, they demonstrate for the first time that there is a single predominant stem cell that is responsible for the production of new neurons in the adult forebrain. The ability to isolate pure populations of stem cells from the brain can be ranked in importance with the first successful isolation of the blood stem cell: it now allows the direct examination of the properties and regulation of this cell. It provides the means to discover how this cell can be regulated to produce new nerve cells and identify drugs to be used to activate new nerve cell production. Just as isolating the blood stem cell has facilitated the discovery of drugs to stimulate new blood cells after diseases, the brain stem cell will provide a real opportunity to find drugs that can stimulate the production of new nerve cells following diseases.
How do we find the molecules that can stimulate new nerve cells, quickly?
With the ability to isolate the brain stem cell, the Bartlett group now has the means to directly screen for molecules which can stimulate there growth and regulate the production of new nerve cells. This requires screening large numbers of compounds and testing their efficacy both in the in the tissue culture and in animal models of disease. This is a very costly and labour-intensive enterprise, requiring a team of 10 scientists and technicians to achieve this goal rapidly. The cost of running such an operation is approximately $1.0 million per year. At present, funds to support this quest are running at about $300, 000 per year, thus, there are only 3 scientists working in this area within the Bartlett lab at present.
What Diseases Are Potentially Treatable with this Approach?
Since traumatic Head and Spinal cord injury, as well as Motor Neuron Disease (ALS), Parkinson's, Alzheimer's, Stroke all are caused by loss of nerve cells, drugs that can stimulate new nerve production are capable of being used therapeutically in all these diseases. Much the same way as the drugs stimulate new blood cells in a wide variety of diseases, it is envisaged a similar revolutionary approach will be possible in brain and spinal cord repair.
Can the Bartlett group deliver?
The Bartlett group has been involved with the development of a factor that stimulates nerve cell survival, LIF, which is now under Phase II clinical trials. In addition, the molecules that stimulate blood cell production -now responsible for $2US billion dollar industry - were discovered at Bartlett's Institute, so there are the capabilities in-house to do this. Finally, Bartlett's group is the only group in the world with the capabilities to purify the stem cell for the drug-discovery process.
THE WALTER AND ELIZA HALL INSTITUTE- DR. ROD RIETZE
For more than a century it was believed that the adult brain and spinal cord were a static organs, where no new nerve cells were produced following their original generation during development. Two major discoveries - that new nerve cells are being generated and that neural stem cells (NSCs) reside in the adult brain - have since challenged that dogma and convincingly demonstrated that the adult brain and spinal cord retain the ability to produce new nerve cells throughout life. Although the everyday production of new brain cells in the adult was originally demonstrated in two regions, namely the olfactory bulb (which is essential in maintaining our sense of smell) and the hippocampus (which is involved in the formation of memories), more recent investigation has revealed that new nerve cells are generated in several other regions including the cerebral cortex and the spinal cord. Furthermore, investigation into the part they play in the adult brain revealed that these new cells served a functional role in the life of the animal, and were not just aberrant events.
While these discoveries brought renewed enthusiasm into the field, investigators remained cautiously optimistic. It had yet to be demonstrated that endogenous stem cells - those precursor cells already residing in the brain and spinal cord - had the ability to replace nerve cells which where lost due to injury or disease. That is, until now.
Two recent papers now report that endogenous precursor cells can be activated following brain injury, generate new nerve cells, and finally make appropriate connections to the existing circuitry of the brain. Even more exciting is the demonstration in one study, that these newly generated cells contribute to the functional recovery of the stroke associated cognitive defects in memory.
These studies suggest that we have underestimated the ability of the brain and spinal cord to repair itself, and that the possibility of activating endogenous stem cells to replace lost populations of motor neurons now represents a viable avenue of treatment. While the idea of activating stem cells seems straight forward, the scarcity of such cells in the brain (less than 1 in a million cells are stem cells), make them a hard target to hit. How can you determine what effect a treatment has when the cell that you are targeting (whose identity is unknown) represents such a small fraction of the total population? Clearly before definitive experimentation can begin, one must be able to identify and enrich for this stem cell in the brain.
This necessary first step has recently been accomplished by our group through the direct isolation of an essentially pure population of adult neural stem cells. Using a FACS machine (Fluorescent Activated Cell Sorter) - which can sort cells into distinct populations based on the size, content, and specific attributes found on the surface of cells - we have been able to enrich for stem cells such that in a given population of cells, 80% of the cells are stem cells. So, now that we can reproducibly purify a population of stem cells, we are now in the position to unambiguously examine the properties of this cell, and subsequently determine which factor(s) are necessary for its activation in the animal. In the case of spinal injury, our goal is to activate the stem cells known to reside in the spinal cord, so as to replace those cells which have been lost as part of trauma or degeneration.
In conclusion, by being able to identify an adult brain stem cell we are at the beginning of a journey of discovery which will undoubted revolutionize our understanding of the regenerative capacity of the brain and spinal cord and bring about new and effective treatments for conditions caused by trauma, disease, or other neurodegenerative conditions.
Rodney Lee Rietze [rietze@wehi.EDU.AU]
NEURONAL REGENERATION RESEARCH AT THE AUSTIN & REPATRIATION MEDICAL CENTRE
DR. PETER BACHELOR
Following traumatic injury to the CNS (including the spinal cord) axons undergo sprouting adjacent to the site of injury. This form of sprouting has been termed "abortive sprouting" because of the failure of axons to cross the lesion site and undergo true axonal regeneration. The cellular and molecular mechanism of abortive or peri-wound sprouting has been unclear. Our recent studies have demonstrated that it occurs as a result of macrophages (and a related cell type microglia) secreting growth stimulating trophic factors. The model we have utilized involves traumatic injury to the rodent striatum, following which dopaminergic neurons vigorously sprout around the injury site. Our studies3-6 have revealed that after striatal injury activated macrophages and microglia accumulate in the periwound region and express the potent dopaminergic neurotrophins brain derived neurotrophic factor (BDNF) and glial cell-line derived neurotrophic factor (GDNF). Activated microglia appear to play the predominant role initially, stimulating and initiating neurite outgrowth through the production of a gradient of BDNF directed towards the wound edge.
Sprouting axons grow across the surface of these activated microglia and their processes as they traverse towards intense GDNF producing activated macrophages at the wound edge. Although activated macrophages also fill the core of the wound, and also produce BDNF and GDNF, they do so in far lower amounts. Thus the highest amounts of NTFs are produced by macrophages and microglia at the wound margin, and it is towards these cells that sprouting neurites grow and surround, but do not extend beyond. Sprouting fibers therefore appear to grow along a trophic gradient formed by increasingly activated microglia towards the lesion edge where their growth is "arrested" over macrophages expressing the highest amounts of trophic factors. These data suggest that axons may fail to cross the lesion site because of an absence of a continuing gradient of locally active trophic molecules. Our observations imply that successful regenerative growth requires a proximal-distal gradient of increasing, or at least constant (but not decreasing), trophic support. We are currently constructing and implanting artificial gradients of trophic factors to determine whether axonal regeneration can be stimulated beyond the lesion edge and across sites of CNS injury.
IN THE FIRST FEW DAYS AFTER CNS INJURY, RATHER THAN SECRETING GROWTH FACTORS AND STIMULATING AXONAL SPROUTING, MACROPHAGES INSTEAD APPEAR TO GREATLY ACCENTUATE TISSUE DAMAGE, A PROCESS KNOWN AS SECONDARY INJURY. SECONDARY INJURY RESULTS NOT ONLY IN ADDITIONAL TISSUE LOSS, BUT ALSO IN THE LOSS OF CELLS SUCH AS OLIGODENDROGLIA WHICH MYELINATE SURVIVING AXONS. OUR GROUP IS THEREFORE ALSO EXAMINING WAYS WHEREBY EARLY AFTER INJURY MACROPHAGES CAN BE RAPIDLY TRANSFORMED TO A GROWTH SUPPORTING PHENOTYPE, TO HOPEFULLY HELP MINIMISE THE DEGREE OF SECONDARY INJURY.
A DEVELOPMENTAL APPROACH TO THE PROBLEM OF REPAIRING THE INJURED SPINAL CORD
Professor Norman Saunders at Melbourne University
It has been a long held belief dating back to the 19th Century that the immature nervous system would recover from injury more effectively than the adult. However, until recently the evidence has been contradictory and confusing. It is now clear that the immature nervous system is indeed better at repairing itself, but in order to demonstrate this ability unequivocally it is necessary to study injures at very early stages of development indeed, in the fetus in conventional laboratory animals such as rats. This was tried in several experiments in the 1920s and 1930s, but only one experiment in an Italian laboratory appears to have been successful, but was not followed up.
Our approach has been to use a marsupial species, the grey South American short-tailed opossum (Monodelphis domestica). The reasons for choosing a South American species have to do with availability and animal husbandry in a laboratory environment. These animals are not related to possums, except in the very distant evolutionary past. Marsupials are born at an extremely early stage of development compared with animals such as rats or cats. A newborn opossum is in many respects similar to a rat fetus about two thirds of the way through the gestational period, which lasts for 3 weeks. Their big advantage is that they are accessible for experimental manipulation at this very early stage of development. Our group has now shown that these animals, if their spinal cord is completely transected at the age of 1 week, will show a remarkable degree of recovery and normal development, as well as structural repair of the damaged spinal cord. If the injury is made later in development (eg after 2-3 weeks of age) this recovery does not occur.
A problem of interpreting the successful recovery in these immature animals is that the nervous system is still developing and growing. Thus at the time (eg 1 week) when the injury is made, some nerve fibres have not yet extended from the brain to the site of injury in the spinal cord. These fibres subsequently grow through the disrupted site of injury and presumably contribute to the recovery. An important question is how many of the nerve fibres that grow across the site of injury were injured and then regenerate, since this is the process we would like to understand in order to discover new ways of treating spinal cord injuries. This has been answered recently by two of our PhD students, Elizabeth Fry and Helen Stolp, who have shown that about 30% of the nerve fibres injured at one week of age regenerate and are still present when the animals become adult. What happens to the other 70% we do not yet know. Probably they fail to survive because they do not make appropriate connections in the spinal cord and brain. A next important question, which is technically even more difficult than the problem of demonstrating regeneration, is whether the connections made by the regenerating nerve fibres are normal and to what extent they are contributing to the functional recovery. Another important question is the relation between the amount of structural repair and the amount and quality of behaviour that can be demonstrated.
It is widely believed that a relatively small growth of nerve fibres will result in significant functional recovery, but the experimental evidence for this is poor. One of our PhD students, Michael Lane has shown that there is a direct correlation between the amount of tissue repair at the site of injury and the amount of motor behaviour. The tissue at the repair site contains nerve fibres, it remains to be shown if there is a correlation between the number of nerve fibres and amount of behaviour. The overriding interest of a developmental approach to repairing the injured spinal cord is to understand the changes occurring during development that take the spinal cord from a state in which it can repair to one in which it cannot. Understanding these processes could lead to development of novel therapies for spinal; cord injury.
This is a problem of molecular and cellular biology. Our colleague in Trieste, Italy, Prof John Nicholls has made a start on a molecular analysis of developing spinal cord. We have preferred to establish some important background on regenerative ability and formation of functional connections, since these are processes that are crucial to developing repair strategies. The group is also involved in developing methods of delivering drugs and other compounds to the brain and spinal cord across the "blood-brain barrier". This will be essential for any spinal cord injury therapies that involve growth factors or other externally applied agents. Overall a developmental approach is a long term one based on the belief that developing nerve fibres are so good at growing, that it should be possible to revive such ability in older nerve cells and thus develop new ways of repairing the injured spinal cord.
Developmental and Trauma Group
Department of Pharmacology and Centre for Neuroscience
University of Melbourne
Norman R Saunders, Professorial Fellow in Neuroscience
Kate Dziegielewska, Associate Professor
Mark Habgood, Senior Research Fellow
Joakim Ek, Postdoctoral Research Fellow
Ann Potter, Research Technician
Elizabeth Fry, Research Fellow
Michael Lane, PhD student
Helen Stolp, PhD student
Pia Johansson, PhD student
Cell therapy for Parkinson's disease: a stepping-stone toward a cure for spinal cord injuries.
By David Haylock, Stem Cell Research Laboratory, Peter MacCallum Cancer Institute.
Our laboratory is presently supported from the Spinal Cord Society of Australia and the Lions Club of Traralgon to assist in the development of cell therapies for treatment of spinal cord compression injuries. This concept involves propagation of cell populations from stem cells isolated from adult tissues such as the brain and potentially the bone marrow. As a first step toward this long-term goal we have elected to use Parkinson's disease as a model for isolation and propagation of neuronal cells from central nervous system stem cells.
For sometime, the management of Parkinson's disease has been viewed as three categories: protective or preventative treatment, symptomatic treatment, and restorative or regenerative treatment. To a large extent, drug therapy, particularly that based on levodopa, has and continues to be the cornerstone for symptomatic treatment. However, in recent times there has been a resurgence of functional neurosurgical procedures in the treatment of this disease. A part of this activity includes the transplantation of cells into the brain. The underlying premise of this approach is that injected cells survive and function as normal dopaminergic neurons and in doing so restore motor function.
Numerous attempts have been made to replace dopaminergic neurons in diseased brain by grafting different types of dopamine secreting cells including human fetal tissue rich in dopaminergic neurons, autologous adrenal medulla cells, dopaminergic neurons from other species etc. Within the United States, over a 1000 patients have been grafted with neuronal cells isolated from these sources. The results of these types of cell replacement therapies are encouraging but the heterogeneity of transplanted cells, risks of immunological rejection and other problems related to the source of the transplantable material have raised numerous concerns about cell therapies.
Recently, adult nervous system stem cells have been discovered and prospectively isolated from mammals. In addition, methods have been devised for propagation of these nervous system stem cells so that dopaminergic neurons or at least dopamine producing cells can be produced. These advances provide an opportunity for in vitro propagated human neuronal cells to be used for cell replacement therapy of Parkinson's disease. Human central nervous system stem cells can be isolated from foetal as well as adult brain. Isolation of stem cells from the adult brain facilitates autologous transplantation that eliminates risks of immunological rejection and transmittable infectious disease and moreover solves the practical and ethical problems associated with obtaining sufficient foetal or embryonic tissue for this therapy.
Accordingly, the pre-clinical studies performed within the Stem Cell Research Laboratory at the Peter MacCallum Cancer Institute are based on in vitro culture of a patients own central nervous stem cells then generation and implantation of dopaminergic neurons. This strategy has already been successfully applied in a clinical study performed in at least one centre within the United States.
The process involves surgical resection of a small amount of a patient's own brain tissue, the dissociation of the neural cells then culture in a media supplemented with a combination of growth factors/mitogens that promote survival and proliferation of central nervous system stem cells. Within a week or so, the presence of stem cells is heralded by the appearance of small, round, ball-like collections of cells termed neurospheres, that contain neural and glial cells and importantly a small number of stem cells with the capacity to regenerate more neurospheres. Continued expansion of the culture is achieved by dissociation of the neurospheres and re-culture in fresh media and growth factors. This process is typically performed every 3-5 days to ensure that cell number continues to increase. At some point the cultures are exposed with agents to induce differentiation of cells into neurons that produce dopamine or other neurotransmitters as required.
The overall objective of these cultures is to generate a sufficient number of dopaminergic neurons that when transplanted back into the brain will produce enough dopamine to alleviate or decrease Parkinson's symptoms. As this approach is relatively new, there is little information on how many neurons need to be injected for clinical benefit. The knowledge we gain from these studies will enable us to refine methods for propagation of other neural and glial cell types for use in treatment of spinal cord injuries. Minimal invasive, but open reconstruction of the anterior column of the thoracic and lumbar spine.
Professor Thomas Kossmann, MD FRACS,
Director Department of Trauma Surgery,
The Alfred Hospital
Prahran, Victoria 3141
Phone: 03 9276 3386
Fax: 03 9276 3804
Minimal invasive approaches to the thoracic or lumbar spine were introduced in the early 1990`s inspired by the success of endoscopic thoracic and abdominal surgery. The main goal of these efforts has been the reduction of the surgical trauma, since anterior open approaches to the thoracic or lumbar spine were associated with a significant complication rate, like intercostal neuralgia and post-thoracotomy pain syndromes. The first results of endoscopic spine surgery clearly demonstrated the benefits of these new techniques in terms of reduced surgical trauma and reduced blood loss with an evident decrease of blood transfusion, less pain at the site of the operation, an improved postoperative respiratory function, a reduced access morbidity, less hospital stay and therefore reduced costs.
A variety of minimal surgery access strategies to the thoracic and lumbar spine have been developed in the recent years, named either minimal invasive spinal surgery (MISS), video-assisted thoracoscopic surgery (VATS), laparoscopy-assisted spinal surgery or retroperitoneal endoscopic surgery. The obvious advantages of the minimal invasive strategies to the spine are diminished by the disadvantages due to increased anesthesiological monitoring, long learning curve for the surgeons, longer operation times and considerable financial investments for an endoscopic set-up and disposable instruments. A minimal invasive, but open procedure to the anterior part of the spine combines the previous mentioned advantages of the "pure" endoscopic approaches with the ones of an open procedure, i.e. direct view of the anterior part of the spine, safer mobilisation of nerves and vascular structures, faster decompression of the spinal canal and easier reconstruction of the anterior column.
The authors has developed a new method in which the anterior column of the thoracic and lumbar spine was reconstructed through an open, but minimal invasive approach and used in different clinical applications, like spinal fracture care, pseudarthrosis and tumor resection The major advantages of this method are the direct three-dimensional view of the spine without the mandatory use of a thoracoscope and no need for double-lumen intubation as well as a relative short learning curve for the surgeons.
The clinical results of over 140 operations since 1999 clearly demonstrate that this technique is safe and easy to learn. So far no serious complications regarding the access has been experienced as described in other studies using a classical open approach like postoperative paraplegia, vessel laceration and infections which had been reported up to 11.5%. Furthermore, the described new access technology has additional advantages compared to "pure" endoscopic techniques in terms of a reduced complication rate, less operation time and easier management of possible complication(s).
Interestingly, blood transfusions could be drastically reduced, since the introduction of the new access technologies. Altogether a substantial reduction of approximately 70% compared to the previous open procedures could be achieved (unpublished data, T. Kossmann). The new method is economic not only in terms of human resources, but also in terms of financial investments for endoscopic instruments and disposable materials. For instance, in laparoscopic or retroperitoneoscopic approaches to the lumbar spine special designed, expensive disposable trocars must be used to guarantee the pneumoperitoneum. This operation method has no disposable items and all parts of the system are autoclavable, which is another major advantage of this technique. In summary minimal invasive, but open has become the standard access to the anterior thoracic and lumbar spine.
The role of cerebral inflammation after traumatic injury to the brain
Cristina Morganti-Kossmann, Thomas Kossmann, Jeffrey Rosenfeld, Jamie Cooper at The Alfred Hospital
A traumatic injury to the brain affects primarily young individuals all over the industrialized countries and approximately 25% of these remain with long lasting disabilities, becoming a familiar, social and economic burden for the society. Despite a lot has been done particularly on safety rules of road traffic to diminish the consequences of motor vehicle accidents, in these patients morbidity and mortality are still high. If the primary injury cannot be prevented, the reduction of secondary brain damage could, thus keeping many scientists and physicians occupied in search of novel forms of treatment to neutralize the effect of neurotoxic pathways. The therapies available today to treat brain injury are unfortunately still limited and further research is required to find new drugs, which in the long term may limit the damage caused by trauma.
We have founded an interdisciplinary group of researchers comprising medical and basic scientists working at the Departments of Trauma Surgery (CM-K, TK), Neurosurgery (JR) and from the Intensive Care Unit (JC) all located at the Alfred Hospital. We all share a particular interest on brain injury caused by trauma.
We are studying the role played by cerebral inflammation, which occurs in the brain after trauma. Inflammation can, on the one hand, contribute to the mechanisms of tissue repair but on the other hand, aggravate the injury by adding further damage to the brain causing neuronal cell death. In the clinical project, we collect cerebrospinal fluid from patients with severe head injuries after the insertion of intraventricular catheters; a medical procedure, which helps to decrease the deleterious effects of elevated intracranial pressure. These samples are used for measuring the concentrations of various inflammatory mediators and other molecules related to the cascade of programmed cell death and to assess their possible relationship with clinical parameters such as extent and type of brain injury, blood-brain barrier dysfunction, secondary brain damage, neurological deficit and final outcome. In order to compare cerebral with peripheral immune activation, whole blood samples will be collected at the same time and analysed for the same molecules. The main scope is to determine whether cerebral inflammation is associated with the degree of brain tissue damage. In addition, this study offers the opportunity to compare the findings obtained in our laboratory on experimental models of traumatic brain injury using mice or rats and to determine whether they are applicable in human brain injury. The project does not interfere with the therapy and does not produce any harm to the patients and is conducted after approval of the ethics committee.
Institute: Centre for Functional Genomics and Human Disease. Monash Institute of Reproduction and Development. Monash University.
Project: The involvement of oxidative stress in neural injury.
Team Leader: Dr Peter Crack
Stroke is the leading cause of disability in Australia and ranks as the third leading cause of death after heart disease and cancer. Approximately 80% of all strokes suffered are caused by a blood clot that reduces blood flow to the brain. Consequently, brain regions normally supplied by the occluded or blocked vessel are starved of vital oxygen. The process of reperfusion or re-initiation of blood flow that follows occlusion results in re-oxygenation to the region. However, this process often causes an increase in oxygen levels, which cannot be utilized by neurons under normal conditions. This rapid increase in oxygen leads to the generation of excessive reactive oxygen species (ROS). Anti-oxidants like the enzyme glutathione peroxidase-1 (GPX-1) are used by the brain to try and combat the rise in ROS. While the primary function of GPX-1 is in the detoxification of these radicals, the role of GPX-1 during a pathology such as stroke has not yet been completely elucidated.
In stroke, the initial damage that is caused by the lack of blood is irreversible. However, the damage that is caused by reperfusion, which is often the major damage to the brain, is potentially reversible. This secondary damage is time critical, ie: there is a therapeutic window in which the damage can be reversed. At the moment, this window is in the space of hours and the therapies available, while somewhat effective are far from ideal.
An area we are currently focusing on is in the elucidation of the role GPX-1 plays in the severity of neural damage seen following stroke. This can be examined by studying the consequences of stroke in mice, which we have genetically manipulated so that they express a non-functional GPX-1 gene. We are one of a handful of laboratories in the world, which can successfully perform mid-cerebral occlusion (MCA) surgery on mice. Stroke induced by this form of surgery most closely resembles the type of stroke, which occurs in humans. To date our data indicates that a loss in GPX-1 function results in compromised neural cell viability and a major increase in the size of infarct (Figure).
Figure. Panel A represents a normal, wildtype mouse that has undergone the MCA surgery to induce stroke.
Panel B represents a genetically altered GPX-1 knockout mouse that does not express GPX-1 that has undergone the MCA surgery to induce stroke. For both panels the time point 24hrs after stroke. Shaded is viable tissue. White is damaged area. (Crack et al J Neurochemistry 2001, 78, 1389-1399).
This mouse model is also being used to screen novel compounds for neuroprotective characteristics. Using micro array analysis we hope to identify future therapeutic targets that will enable the development of the next generation of neuroprotective drugs. To this end we have identified a number of potential target genes that maybe involved in the pathology of stroke and effected by oxidative stress. It is likely that these genes are also involved in other neuropathologies such as blunt head trauma. Future studies will be directed to this model for assessing the ability of stem cells to reverse the damage associated with neural injury.
Dr. Bevyn Jarrott at the Monash Institute of Reproduction and Development.
Mechanical injury to the spinal cord due to either compression of the spinal cord or to severing of the spinal cord has generally been regarded as causing permanent paralysis to those parts of the body that are innervated by nerves that leave the spinal cord at or below the site of injury. However, due to recent studies in laboratory animals, ways and means are being found to minimize the damage to the spinal cord after either a crush or a cut to the spinal cord and this results in partial recovery of function previously thought to be impossible. Recent studies in laboratory rats with a drug, Minocycline, which was developed as an antibiotic with anti-inflammatory properties, have shown that it reduces the secondary inflammation that progresses over a period of days to weeks after brain injury. However, this drug is no longer covered by an exclusive patent and so drug companies are not interested in investing in research studies to establish if Minocycline will reduce spinal cord injury and partially restore function.
Also, the market for the treatment of acute spinal cord injury is too small to justify this cost of research. Thus, organizations such as the Victorian Trauma Foundation have an important role in supporting research to find drugs to minimize damage after spinal cord trauma. This Foundation has awarded us funds to do this research to determine the usefulness of Minocycline in a rat model of compressed spinal cord injury. We will investigate what is the effective dose range to minimize spinal cord injury and what is the longest delay after spinal cord injury that Minocycline can be administered and still be protective. Obviously, if the delay before starting treatment is of the order of three to four hours and not 20 to 30 minutes then the drug would be very promising for minimizing the devastating consequences of traumatic spinal cord injury.
Professor Alan Trounson from the Monash Institute of Reproduction and Development.
The research programs for the new Biotechnology Centre of Excellence are being established and include both embryonic and adult stem cell biology with the aim of therapeutic applications. A recent publication in the journal Cell, and a manuscript under review in the journal Nature Medicine, show that embryonic stem cells can form motor neurones that will contribute to fully formed spinal motor neurones in embryonic chick spinal columns, and that nerve precursors from embryonic germ cells reverse paralysis in rats with viral induced motor neurone defects. A team of neuroscientists will be exploring these new opportunities within the new National Stem Cell Centre (NSCC). In the adult stem cell research program, the NSCC will continue to explore the effectiveness of mesenchymal stem cells for treating Parkinson's Disease. Other major research programs include transplantation biology aimed to improve the effectiveness of cell and tissue transplantation and the role of the immune system in regain of normal tissue function during stem cell repair. The Centre's other major research area is in tissue engineering, which will focus on the construction of tissues in the laboratory for grafting purposes.
Given the importance of embryonic stem cells for the potential repair in a wide range of diseases, pathologies and injuries, the Centre's key scientists have been contributing to the scientific, community and parliamentary debate. Despite a very active campaign by conservative religious members of the community who had brought two US scientist-ethicists to argue against embryonic stem cell research, the general Australian community and Parliamentary members remain fully supportive of both adult and embryonic stem cell research. Hopefully we can access some stored IVF embryos that are donated to research to prepare new "gold standard" cells lines for the NSCC and Australian researchers.
It was of interest that Dr Catherine Verfaillie from the University of Minnesota, who recently described the very interesting pluripotential adult mesenchymal stem cells, believes that both adult and embryonic stem cell research must continue as a matter of some importance for eventual therapeutic applications. Dr Verfaillie gave a public lecture at Melbourne University on 22nd August, 2002.
Dr Lynne Bilston at the Prince of Wales Medical Research Institute.
Dr Lynne Bilston has recently joined the Spinal Injuries Research Centre at the Prince of Wales Medical Research Institute. As a biomechanical engineer, her research focuses on the response of the spinal cord to mechanical loading, which may occur during traumatic spinal cord injury, or as a result of chronic loads from, say a fluid-filled cyst in syringomyelia. Recent work has included the development of a novel animal model of spinal cord injury that mimics the injury to the spinal cord that occurs when there is a fracture-dislocation to the spine. This allows us to examine the effects of this type of loading on the spinal cord, and how the injury differs from crush-type injuries. We hope to use this to better understand how injury develops, and also to use this as a basis for studying therapies to improve spinal cord function.
She is also studying the mechanisms of injury to the spine in children during car accidents. In this project, real world accidents are being analysed, and then reconstructed on a miniature crash sled in the laboratory. This will help to determine how the improvement of child restraint, booster seat and seatbelt design can reduce spinal injuries in children up to the age of eight.
Dr Bilston is also collaborating with neurosurgeon Dr Marcus Stoodley and some engineering colleagues in research on syringomyelia, where fluid-filled spaces can form in the spinal cord either after spinal cord injury, or associated with congenital conditions. If they become enlarged, they can cause neurological problems. They have developed a novel computer model that, for the first time, appears to offer an explanation of how the fluid is pushed into the syrinx as a result of the blood pulsing along arteries into the spinal cord.
Dr. Peter Nicholls at the Prince of Wales Medical Research Institute (POWMRI)
Research into Spinal Cord Function after Injury
The functions of the spinal cord are unknown to us in terms of detail. A lot of movements are controlled by the spinal cord, with the brain just initiating the movement. Examples of this include walking and reaching out to grasp an object. In both these type of movements the brain gives the command and the spinal cord takes over and controls the movement in detail through "reflexes". Some of the research at POWMRI is characterising these reflexes in both intact people and those with spinal cord injuries (SCI). This is done by stimulating the limbs with vibration, electrical pulses and other mechanical stimulation and measuring the force produced by limb muscles. Mathematical analysis after an experiment can be used to determine what types of nerve circuits in the spinal cord were involved.
There are two main reasons for doing this. The first is to partly restore function by electrical stimulation. Devices such as the Cleveland hand stimulator and the Neopraxis leg stimulator are designed to do this in people with SCI. One of the problems with this approach is that the movements are coarse and the muscles fatigue easily. These same devices could be used to take advantage of the reflexes that are known to be still functioning below the site of injury in the cord of a person with SCI. It has been shown that if electrical stimulation is used to activate these reflexes, rather than directly stimulating the muscles, a more natural movement with less fatigue is produced. The second reason for charactersing the reflexes is to monitor spinal cord repair in the future. At POWMRI, as well as other research laboratories around the world, people are looking at ways of inducing the nerve cells in the spinal cord to repair themselves after injury. It has been found from work on animals that sometimes the growing nerve fibres do not always make the right connections. So it is necessary to be able to monitor this repair process to ensure it is making the right connections and to correct it otherwise. To be able to do this we must be able to characterise all the spinal cord reflexes. We still have a long way to go, but are making progress.
Dr. Vaughan Macefield and Dr. Stella Engel from the Prince of Wales Medical Research Institute
At the new Spinal Injuries Research Centre at the Prince of Wales Medical Research Institute in Randwick, Sydney, Dr Vaughan Macefield and colleagues are studying autonomic dysreflexia, the dangerous increases in blood pressure that can be caused by over-distended bladders, for example. These reactions have been known to cause fatal strokes and cardiac arrest, and are caused by increases in nerve traffic to the blood vessels (part of the autonomic nervous system termed the "sympathetic nervous system"). With colleagues from Sweden - Professors Gunnar Wallin & Mikael Elam from Sahlgrenska Hospital in Gothenburg - Dr Macefield has established clinical monitoring programs - in collaboration with Dr Stella Engel, Director of the Spinal Unit at The Prince of Wales and Prince Henry Hospitals - to better understand the underlying mechanisms of autonomic dysreflexia.
These programs include recording the changes in blood pressure, skin blood flow and sweating above and below the spinal lesion during resting conditions and during manoeuvres, such as urodynamics assessments (assessing the function of the bladder by infusing known volumes of water via a catheter), which can trigger autonomic dysreflexia. In addition, by inserting a fine needle into a nerve in the leg, the researchers have been tapping into the remaining nerve fibres that can remain intact following a spinal injury, important research that is only being performed in Sydney and Gothenburg. However, they have shown that it is not only nerve fibres within the spinal cord that are damaged during spinal injury - those in the peripheral nerves, which convey signals to and from the spinal cord to the limbs and torso, are also affected. This is a surprising result, given that it is generally assumed that the spinal cord below the lesion is intact, and that the nerves to the paralyzed limbs are normally able to transmit messages from the spinal cord to the muscles. By examining the electrical properties of the motor nerves in the legs, Prof. David Burke and Dr Matthew Kiernan have shown that the nerve fibres to the muscles (motor axons) often can no longer conduct electrical impulses following spinal cord injury. This suggests that, following spinal injury, the absence of the normal voluntary motor commands leads to chronic changes in the electrical properties of the motor axons in the periphery. They propose that axonal atrophy occurs, either by the axons dying back or by changes in the ionic mechanisms that are responsible for the propagation of signals along nerve fibres.
This axonal atrophy ultimately results in muscle atrophy - wasting of the muscles - which is a fundamental limitation to the effective rehabilitation of the muscles. By understanding these changes the researchers hope to be in a position to introduce strategies that will prevent these changes from occurring, by intervening as soon as possible after the spinal injury. Currently, physiotherapy is performed on the joints and muscles of these patients to prevent stiffening of the limbs. But the scientists at The Prince of Wales Medical Research Institute believe that the rehabilitation process of patients with spinal injuries needs to undergo a significant change, by including techniques that will keep the peripheral nerves healthy. In this way, any residual intact pathways within the spinal cord will be able to reach their targets in the limbs, and when regrowth within the spinal cord can be achieved, the peripheral nervous system will be ready! For further information on this research program, please contact Dr Error! Bookmark not defined. by phone (9382 7926) or email firstname.lastname@example.org It is only through the willingness of people with a spinal injury to participate in research programs such as these that an improvement in rehabilitation strategies can be brought about.
Professor Elspeth M. McLachlan, D.Sc., F.A.A. Co-Director, Spinal Injuries Research Centre,
Prince of Wales Medical Research Institute
Hyperreflexia is a life threatening condition in spinal people in which certain stimuli like a full bladder can trigger a large and prolonged rise in blood pressure. James Brock and Elspeth McLachlan at the Spinal Injuries Research Centre, Prince of Wales Medical Research Institute, Sydney, are working, with help from Melanie Yeoh, to examine the contractile responses of blood vessels from spinal rats to stimulation of sympathetic nerves. The responses are greatly enhanced and prolonged, partly due to the release of increased amounts of chemical transmitter from the sympathetic nerves and partly due to changes in the arterial smooth muscle cells. This work is supported by the Christopher Reeve Foundation and the National Health & Medical Research Council.
Janet R. Keast, PhD
Conjoint Associate Professor UNSW
NHMRC Senior Research Fellow
Prince of Wales Medical Research Institute
Dr Janet KeastÂ¹s group is studying the problems that occur in neural control of the urogenital organs after nerve injury, including after spinal cord injury. They are particularly interested in some of the rapid growth of new (and inappropriate) nerve connections that are triggered by some types of injuries and are studying these in the spinal cord and also in the nerve
pathways that make connections between the spinal cord and organs, such as the urinary bladder. This Â³wrongÂ² growth could underlie problems such as autonomic dysreflexia, bladder sphincter dyssynergia and bladder hyperreactivity. These studies are performed on rats, where the group has already gathered a lot of information on the nerve connections in this part
of the body, and where many of the same types of urogenital problems occur after injury.
There are two main types of studies at the moment. One is to use various types of tracing dyes and fluorescent antibodies to map out in very fine detail the changes occurring in different parts of the pelvic autonomic pathways after injuries. This means that it is possible to see exactly what types of new connections are forming between individual nerve cells, and also whether these new connections are causing changes in the chemistry of the nerve cells. In the second group of experiments they are trying to work out what substances might be causing the wrong nerve pathways to grow or what causes them to grow in the wrong direction. To do this, Dr KeastÂ¹s group is looking at two groups of substances made in some parts of the nervous system, Â³neurotrophic factorsÂ² and Â³guidance factorsÂ². They are starting to map out the places in the pelvic autonomic system where some of these substances are produced and what types of injury may cause more or less of these molecules to be made. Other types of studies are being carried out on isolated nerve cells being grown in culture, so that the
growth-promoting or growth-directing properties of the molecules can be understood in more detail.
This project is about how steroid hormones, especially the naturally occurring sex hormones, testosterone and estradiol, affect the nervous system, especially the part of the nervous system that controls bladder function in women, and reproductive function, such as prostate gland activity and erection, in men. These hormones can change in amount during different reproductive stages, and during ageing. There are also other occasions when pharmaceutical agents are relevant to understanding normal hormone actions. For example, many prostate cancer patients are prescribed a class of drugs called Â³anti-androgensÂ², to try and decrease the chances of cancers growing again - but these drugs often have the side-effect of impotence and this may well be because the drugs affect the autonomic nervous system. Dr KeastÂ¹s work is trying to locate which parts of the nerve supply to the pelvic organs are sensitive to these hormones, by first tracking which nerve cells have receptor proteins for these particular steroids. She is then trying to determine what aspects of nerve cell function the steroids alter - many of these studies use nerve cells grown in a dish (Â³primary cultureÂ²) to look at the biochemical and structural changes in nerves after steroid treatment in greater detail. She is conducting these studies in autonomic nerve cells that control reproductive organ activity in males and in sensory nerve cells that signal changes in bladder fullness and pain in females. All of these studies are currently being performed in rats and mice, where we already know a lot about bladder and reproductive control, and where there are quite a few basic similarities to the human system.
Department of Anatomy & Developmental Biology
University of Queensland
Associate Professor Brian Key and Dr. James St John
Our laboratory consists of a research scientist (Dr. Simon Kinder), a senior research assistant (Tina Claxton), 5 research assistants (Lynh Nguyen, Kendra Coufal, Tracey Ainsworth, Vicki Hunter, and Adrian Carter), 4 Doctor of Philosophy students (Nicole Wilson, Melonie Storan, Rob Connor and Christine Devine) and 2 Bachelor of Science Honours students (Chelsea Allen and Nigel Kee). The laboratory is funded by the National Health and Medical Research Council and the Australia Research Council to undertake research into the molecular and cellular mechanisms underlying the growth of nerve processes in the brain. The underlying philosophy to our work is that if we can understand these mechanisms in the normal developing brain then we should be able to apply this knowledge to the design of therapeutic approaches to the repair of damaged neural tissue. One of the model systems we are particularly interested in is the olfactory system - the region of the nervous system responsible for detecting odours. The nerve cells in this region of the nervous system have evolved a remarkable ability to regenerate throughout life - whereas as most regions of the brain fail to regenerate after injury, olfactory nerve cells are unique for their ability to regrow and from new connections in the brain, even after quite extensive injury. In addition to studying normal development we have been investigating the ability of these cells to grow back to their original sites in the brain after injury. It is absolutely important that we understand not only how to promote regrowth of nerve cells but to ensure that the regrowth is to the correct location. It is not enough for a Telstra technician to connect together a severed telephone cable - the wires need to be individually reconnected otherwise messages will be scrambled. It is exactly the same for nerve processes.
We have been studying the biology of a special population of cells called ensheathing cells - these cells act as conveyor belts for directing the growth of axons across injury sites. Unfortunately these cells lack the ability to direct the growth of nerve processes to their correct targets. We are now trying to understand the signals that provide the navigational cues to these processes to ensure that they are re-wired correctly. Although this is proving a challenging task, we have some interesting candidate molecules that we are currently examining. Our strategy is to genetically alter the position of these molecules during development in mice and to analyse the resultant effects on the growth of nerve cells. This is the first step towards their subsequent use in the regenerating nervous system. This is not an easy set of experiments and there is no sure outcome. Meticulous and carefully planned experiments are essential if we are to make any headway. Our lab is committed not only to understanding these mechanisms but also to the training of a new generation of neuroscientists with the skills and know-how to complete our goal.
Professor Mackay-Sim and his team at the Princess Alexandra Hospital
An Australian surgical team has started the world's first clinical trial on spinal cord regeneration, giving hope to millions of paraplegics. The surgeons transplanted nasal cells into the spinal cord of a volunteer paraplegic patient during a historic eight-hour operation in Brisbane last month. They used a specially designed device to inject 14 million cells into several injured regions of the patient's spinal cord. Three more patients are awaiting the trial surgery. The process follows successful laboratory experiments at Brisbane's Griffith University, and in Spain, where rats whose spinal cords had been severed were able to move their legs just weeks after transplanted nasal cells triggered regeneration of the damaged area.
But key figures in the Queensland Spinal Cord Regeneration Project cautioned against expectations the treatment would enable paraplegics to walk again. They said it would be some months before any changes in the volunteers became evident -- if at all -- and that each patient in the trial would undergo tests to see if there was any improvement in their condition. The remarkable operation was performed at the Princess Alexandra Hospital by a team led by the head of neurosurgery, Dr Adrian Nowitzke, and visiting surgeons, spinal specialist Dr Paul Licina and ear, nose and throat specialist Dr Chris Perry. Team member Dr Tim Geraghty, the director of the spinal injuries unit at the hospital, emphasised that the trial was all about the safety of the procedure.
"We're not expecting too much at all," Dr Geraghty said. "This is to try to prove that we are not going to do any harm, which is the whole purpose of a phase one trial. "If we get some positive outcomes, even better . . . like feeling coming back in the legs or an improvement in bodily control functions."
Professor Alan Mackay-Sim who, with French neurobiologist Dr Francois Feron, grew the cells in a culture at Griffith University's Centre of Molecular Neurobiology, stressed the project team's expectations would be much more conservative than the public's. The identity, even the sex, of the patient who underwent surgery and of the three other volunteers who will be operated on later in the trial have been kept secret. This is to ensure the scientific validity of the trial, with clinicians deliberately being kept in the dark about which of eight volunteers -- five of whom are still to be selected -- has undergone the surgery. A team member said the volunteers, who were approached this year, were given all information possible about what the trial involved to ensure they knew all the risks involved. They then were subjected to a series of psychiatric tests and to psycho-social counselling to make certain they could cope with the stresses of the trial.
Because the spinal cords of patients who suffer a major cord injury can have functional recovery in the six-month period after their accidents, only people who had been paralysed from the waist down for at least six months were selected for the clinical trial. This was to ensure that the project team did not give itself a head start by working with volunteers who were not severely disabled. Despite the tight selection criteria, team members are bracing themselves today for a flood of requests from paraplegics and their relatives seeking admission to the trial. The trial, a collaboration between Princess Alexandra Hospital clinicians and Griffith University scientists, has been supported by a $200,000 grant from the PA Hospital Foundation.
The cells injected into the first volunteer came from the olfactory mucosa, the nasal mucous membrane. This is the only area of the nervous system outside the brain that re-grows. In contrast to most nerve cells, these continue to regenerate throughout life. Indeed, Professor Mackay-Sim said his team had been able to regenerate such cells taken from a person who had died a day earlier. Special olfactory mucosa cells known as olfactory ensheating glial cells are able to enter the central nervous system and guide sensory nerves to grow and reconnect to the brain.
Professor Lyn Beazley at the University of Western Australia
Professor Lyn Beazley heads the Neurotrauma Research Program (Western Australia, an initiative funded by the Road Safety Council of the State. The funds generated through speed camera fines underpin the research that is undertaken collaboratively between laboratories at the University of Western Australia, Queen Elizabeth II Medical Centre and Royal Perth Hospital. The researchers, both basic scientists and clinicians, have research interests in preventing cell death after nerve injury, stimulating axonal regeneration and the formation of appropriate connections after regeneration. Professor Beazley's own work involves the formation of specific topographic projections between the eye and the brain during optic nerve regeneration. Her work is relevant to the injured spinal cord in which appropriate connections must reform after injury.
Dr Giles Plant at the University of Western Australia
Dr Giles Plant currently Directs the Red's Spinal Cord Research Laboratory in the School of Anatomy and Human Biology at the University of Western Australia. The lab is purpose built to perform all aspects of spinal cord injury research from surgery, tissue culture and anatomical studies. My research concentrates on the theory of autotransplantation to repair spinal injuries. This involves the transplantation of cells into the injury site obtained from the same animal's body. This technique avoids any rejection problems encountered from non-self transplants. The cell types we currently transplant include Schwann cells taken from the sciatic nerve, which is part of the Peripheral Nervous System (PNS). The PNS has an ability to regenerate a large percentage of its axons, unlike the Central Nervous System which cannot. The regenerative ability of these axons is due mainly to the presence of Schwann cells which produce factors that initiate growth.
Another new cell type, which we use, is the Olfactory Ensheathing Glial (OEG) cell. The OEG resides in area of the CNS that is able to replenish its neurons throughout adult life. The OEG help to provide a permissive growth environment for the new neurons and for this reason the idea of using these cells to transplant to repair CNS injuries was born. My lab is involved with the first demonstration, in collaboration with Dr Joost Verhaagen (Netherlands), of gentically engineering OEG to secrete neurotrophic factors such as Neurotrophin-3, Brain Derived Neurotrophic Factor and also reporter genes such as Green Fluoresecent Protein. Labelling OEG with reporter/tagging genes enables us to track their course in the animal and provides details of their survival and proliferation. The increased secretion of the neurotrophic molecules is an attempt to increase the growth promoting ability of these cells. Preliminary work has shown this to be successful. We also are studying the effects of any regeneration has on animal behaviour - whether this regeneration is functional and the axons are able to innervate their appropriate sites. In addition, we are investigating the mechanisms involved in how OEG work - how they induce axon regrowth and whether they can myelinate axons.