New Hyperbaric Oxygen Treatment at the University of Miami
We are actively recruiting patients to take part in a multi-center trial of ultra high dose Celebrex in ALS. Inflammation plays a significant role in the neuronal degeneration in ALS, and high dose Celebrex slows down the progress of the disease in the mouse model of ALS. This study will evaluate whether ultra high dose Celebrex can delay the progression of ALS in humans.
We are also recruiting a small number of patients for a pilot trial of hyperbaric oxygen treatment. In a mouse model of ALS hyperbaric oxygen has been shown to slow the progress of the disease. One patient from South America appeared to benefit from hyperbaric oxygen, and we will be studying up to five patients. Treatment will be five days a week in the Jackson Memorial Hospital hyperbaric chamber, and ALS patients must have a vital capacity of greater than 80% and be able to walk up and down stairs into the chamber.
There are two studies which will begin in the new year. One is an open label study of the Avanir medication which inhibits excessive crying in the patients with bulbar ALS. We shall be collecting data to see if there is evidence of beneficial effect of this agent on the long term progress of the disease.
Another study which we hope to begin next year is on a new neuroprotective agent.
We would welcome contact from any patient interested in taking part in one of these studies. Patients may contact us by mailing Julie Steele, LPN at email@example.com or by telephone at 305-243-7424.
Walter G. Bradley, DM, FRCP
Director, ALS Clinical Research Program
University of Miami School of Medicine
This is an outline of some of the basic and clinical research that is being undertaken in the University of Miami ALS Clinical and Research Program designed to find the cause and cure of ALS.
A. BASIC RESEARCH
1. Glutamate in ALS
There is evidence from many directions suggesting excess excitotoxicity in ALS, probably from glutamate. Glutamate is a stimulatory chemical released from some nerve endings to carry the nerve signal from one neuron to the next in a chain. It is also released if nervous tissue is damaged. Too much glutamate over stimulates neurons, and can cause them to die.
Perhaps the strongest evidence for there being excess glutamate in ALS comes from Dr. Jeffrey Rothstein's work showing a partial deficiency of the glial glutamate uptake transporter GLT1. This transporter is present on supporting glial cells around neurons, and is responsible for removing glutamate by absorbing it into the glial cells. If there is insufficient GLT1, there will be excess glutamate to over stimulate neurons, predisposing them to early death.
It is uncertain how this deficiency of GLT1 arises. Studies have predominantly used autopsy tissue. To learn more about glutamate in ALS, we have undertaken studies of ALS patients' brains in life using MRI spectroscopy. Using a regular clinical MRI machine with spectroscopy capacity, we have shown that in the motor cortex and brainstem of the brains of ALS patients there is a progressive loss of a chemical, N-acetyl-aspartate (NAA), that is a marker of the number and health of nerve cells. We searched for evidence of an increased signal from glutamate and glutamine in motor cortex and brainstem of ALS patients. Accurate estimation of the amount of these chemicals requires a higher field-strength magnet MRI than we have available, but our findings suggest that the total levels of glutamate and glutamine, which includes both intracellular and extracellular, are decreased.
Work from other laboratories indicates that GLT1 is a complex protein that exists in several different forms in ALS and normal nervous system tissue, and that there are no mutations of the gene for GLT1 that have been found to cause the decreased level of GLT1 protein. Clearly we need a much greater understanding of the role of glutamate excitotoxicity in ALS.
2. Surrogate Markers for ALS
Currently we have no laboratory test available to prove that a patient has ALS, except in the 1 to 2% of patients with mutations of the gene for superoxide dismutase -1 (SOD1). Also currently the only marker of disease progression is the extent of the abnormal neurological signs measured by a Neurologist, such as the amount of muscle weakness, muscle wasting, breathing tests, and reflex changes. Programs to discover drugs to treat ALS use these abnormal neurological signs to measure rates of disease progression. However, because ALS is so variable, drug trials need very large numbers of patients. It may take a trial of 2,000 patients treated for 18 months to prove whether a drug works or not.
It would greatly assist progress in diagnosing and monitoring ALS, and in new drug development if we had a marker that was relatively specific and sensitive for ALS, and which changed as the disease progressed. We and others have used MR spectroscopy to study NAA, a chemical present in neurons. The motor cortex levels of NAA fall as ALS progresses. Other research groups have found that treatment with riluzole that slows ALS disease progression raise the levels of NAA slightly, though we could not confirm that. More research is clearly needed to find a reliable surrogate marker for ALS to assist in programs for more rapid screening of drugs that may benefit ALS.
3. Oxidative Damage in ALS
Though oxygen is essential to advanced life forms, it is also potentially toxic. It appears that when primordial life forms appeared, they did so in the "primeval ooze" at the bottom of the oceans where the oxygen concentration was much less than in the atmosphere today. All cells of humans have a complex system of enzymes and other substances designed to control the effect of oxygen. One of these enzymes is SOD1. Discovery of mutations of SOD1 in about 20% of patients with familial ALS increased awareness that damage of motor neurons by excess oxygen free radicals may be a cause of ALS. Other research groups have shown that there is oxidative damage of proteins and other macromolecules in the nervous tissue of ALS patients.
Somewhat surprising to all of us was the finding by several other research groups that in fact oxidative damage is not the mechanism by which SOD1 mutations produce the motor neuron degeneration in ALS. A great deal of research is under way to find exactly how the mutant SOD1 protein damages the cells.
Mitochondria are intimately concerned with using oxygen in cells to produce energy, and they play a role in controlling oxidative damage within cells. Other research groups have shown that the mitochondria show structural changes in the nervous tissues of ALS patients and animal models. We have a basic research program studying the mitochondria in cells from ALS patients and animal models of ALS. This research is producing evidence that neuronal mitochondria in mouse models of ALS are more susceptible to lack of oxygen than normal neurons. We are studying the mitochondria to learn more about their role in ALS.
B. CLINICAL RESEARCH
1. New Drug Development in ALS
The University of Miami ALS Clinical Trials Division is one of an international group of Centers involved in trials to develop new drugs to treat ALS.
Nerve growth factors are proteins present in the normal nervous system that play a major role in the development of the embryonic nervous system, and may play a role in nervous system regeneration. It is believed that they might be able to slow down the rate of degeneration or improve the rate of repair in such diseases as ALS. They have been shown to do so in animal models of ALS.
We have been involved in trials of ciliary neurotrophic factor (CNTF), brain-derived neurotrophic factor (BDNF), and glial-derived neurotrophic factor (GDNF). CNTF and GDNF did not improve ALS patients, and were not well tolerated. The initial large trial of subcutaneous BDNF showed that it was well tolerated, but did not show an overall benefit. However, there was an apparent benefit in some groups of patients. Therefore the BDNF trials are continuing. In the study that we are participating in, patients are receiving high doses of BDNF subcutaneously. In another trial at other centers patients are receiving BDNF into the fluid that surrounds the brain and spinal cord (the cerebrospinal fluid) by means of a pump implanted under the skin like a pacemaker. Both these trials are still ongoing.
We have also been part of the international collaborative study of a new drug, named xaliproden, produced by the European pharmaceutical company, Sanofi-Synthelabo. This drug is taken by mouth, is absorbed from the gut and can enter the central nervous system. It acts as a nerve growth factor stimulant. The two studies were both double-blind placebo controlled investigations in which patients received either 1 or 2 mg doses active drug or placebo each day. The trial lasted 18 months, and the patients continue to receive open label active drug treatment. In one study, all patients were co-treated with riluzole. In the other study patient were treated with xaliproden alone. The trials are now completed and analyzed. The drug was well tolerated. There was a general trend for the drug to produce a slowing down of the progression of ALS by 10 to 20%. However, statistical confirmation of this benefit was seen in only of the studies, and the effect was less in patients co-treated with riluzole. The implications of these results are still under discussion.
It is likely that there will be new trials of other neurotrophin stimulant drugs that can be taken by mouth. In the meantime we are involved with a number of other multicenter trials of already available drugs to determine if they will produce a benefit in ALS.
2. Search for New Genes Causing ALS
We are collaborating with Dr. Robert Brownís laboratory in Boston in projects to discover more of the genes responsible for familial ALS, and also to discover the genes that either make sporadic ALS patients susceptible to or protected against developing ALS.
We now believe that the disease process in ALS is like a cascade. (1) There are predisposing factors, particularly gene mutations like those in SOD1 that predispose a person to develop ALS. Dr. Brown is looking for these susceptibility genes, working with us and with other collaborators. (2) There must be precipitating factors in the environment or in the personís body that trigger the initial damage to the motor neurons that marks the beginning of the disease. We suspect what some of these might be, but have no proof about any of them. (3) In many cases there are probably processes in a personís nervous system that protect against or repair this damage. These processes may include the enzyme systems that repair oxidative damage and damage to DNA. These protective processes may prevent the disease of ALS ever appearing, or rarely may lead to remission of the disease. Dr. Brown is looking for these protective genes, working with us and with other collaborators. (4) Finally, there are the processes that lead to the disease spreading and progressing.
When we understand each of these 4 steps in the cascade, we will be much closer to being able to treat and prevent the disease of ALS.
3. Investigation of the Preclinical Stages of ALS
We do not know what is happening to the motor neurons in the years and decades before patients with ALS develop symptoms. An answer to this question would provide us with an insight into the biochemical processes leading to motor neuron degeneration. We are studying the motor neuron function in children of patients with familial ALS to determine the answer to this question. Anyone with a family history of ALS who is interested in taking part in this study should contact us through the website or the email address: firstname.lastname@example.org.
4. Research Into the Clinical Care of ALS Patients
The Kessenich Family MDA ALS Center is a multidisciplinary clinic devoted to providing all of the broad range of expertise needed for the optimal care of patients with ALS and their families. This is not a new concept, but it is few centers have been able to provide a true multidisciplinary clinic because of the high cost. We are applying research methods to learn more about how best to provide the care of each specialty discipline for patients with ALS and their families. We participate in the ALS Care Program that provides a national registry and data bank on ALS patients. Through this, we are able to undertake research to compare the outcomes of treatment of our patients in the Kessenich Family MDA ALS Center with national figures. We have a home visit program for homebound and ventilator-dependent patients that we are evaluating for the purposes of this research. We participated in the American Academy of Neurology Program to develop the Practice Parameter that describes the best ways to care for patients with ALS. This is now the basis of a national and international education program to raise the standard of care of ALS patients and their families throughout the world.
C. STEM CELL RESEARCH
D. ALS-LIKE DISORDER AND HIV DISEASE
In two separate studies, American and French researchers described rare cases of HIV-infected patients who developed a syndrome similar to Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig's disease. ALS is a progressive neurodegenerative disorder that causes muscle weakness, impaired movement and ultimately, paralysis and death. HIV infection and AIDS causes a number of different neurological complications.
The findings, which appeared in the September issue of the journal "Neurology" (The publication of the American Academy of Neurology), raised the possibility that some cases of ALS are the result of viral infections. French researcher report tracking 1,700 HIV-infected subjects over a 13-year period. Six of the subjects developed ALS-like illness. "Causes other than HIV for the motor neuron disease were ruled out," said study author Dr. Antoine Moulignier, a researcher at the Adolphe de Rothschild Foundation in Paris. Two of the patients recovered completely, after treatment with HIV drugs, three improved and one stabilized.
Dr. Daniel MacGowan, assistant professor of neurology at Albert Einstein College of Medicine in New York, wrote about a 32-year-old woman who had ALS-like symptoms and also tested HIV-positive. After a regimen of HIV drugs, the woman recovered completely from the ALS symptoms. But MacGowan says that despite the effects of therapy in this patient, it is not clear from this study whether HIV is directly responsible for the ALS-like symptoms or if another virus is involved.
Dr. Ashok Verma, Associate Professor at the University of Miami, Department of Neurology, says "that viruses as a cause of ALS has been speculated for over 30 years. The recent report of six cases from a large group of AIDS patients in France - seen over a period of 13 years, puts another twist to the possible viral cause of ALS. These were all patients with advanced HIV disease and they, among other findings, had limb weakness that resembled ALS. Currently, there are about 40 million HIV infected persons in the world. It is well known that AIDS causes or contributes to dozens of neurological diseases. The recently reported ALS-like disease could yet be another neurological manifestation linked to the advanced HIV disease (AIDS). In many accounts, the picture in this AIDS-linked disease seems different from the one in 'true ALS" and the French authors justly label the new entity as "ALS-like" disease. The improvement in most AIDS-linked neurological diseases, including "ALS-like" disease, following successful suppression of the AIDS virus is expected. It is also possible that, on occasion, ALS has fortuitously occurred with AIDS in the same patient."
Dr. Verma also says that, "While this report emphasizes the need for more research to find the cause, including possible viral cause, and cure of ALS, there is no suggestion that patients with "true ALS' harbor the AIDS virus." "We do not recommend testing for AIDS virus just because the patient has ALS. Nor do we recommend a trial of AIDS drugs in ALS outside a well-planned clinical research study. Currently available AIDS drugs have significant side effects and they are expensive."
According to Walter G. Bradley, D.M., F.R.C.P., Medical Director of Kessenich Family MDA ALS Center, at the University of Miami, a cascade of events causes ALS. Some of these events are:
" A predisposition that is the result of many inherited genes.
" A precipitating factor.
" A counterbalance resulting from a number of probably inherited protective factors.
" Some factors that cause the disease damage to spread in the nervous system.
" Processes that finally kill the motor nerve cells.
HIV infection might be one of the precipitating factors. This study might be showing that ALS could be precipitated many years before it would otherwise present. In such a case, suppression of the precipitating factor might lead to resolution of the ALS, perhaps to present several decades later (if the patient were to survive long enough with HIV infection). Alternatively, as Dr. Verma suggested HIV infection might be causing an ALS-mimic syndrome, and not true ALS. Dr. Bradley also said, "I do not recommend that any ALS patient be given this treatment outside of a well-designed trial."
Further investigations of how viruses play a role in ALS are going to be held by Dr. Stephen Scelsa at Beth Israel Medical Center, NY and Columbia-Presbyterian Medical Center, NY. Funding support for the Scelsa grant comes from the ALS Association Greater New York Chapter with specific support from ZazAngels and the Adele Zinberg, M.D., ALS Research Fund.
The study, which began October 1, is a placebo-controlled investigation with 46 patients to assess whether Indinavir, a protease inhibitor used in the treatment of HIV infection, slows the progression of ALS in patients that are negative for HIV and to investigate the possible mechanism of the compound.
Patients will be eligible to be enrolled in this study if they have ALS, have a forced vital capacity of >50% of predicted, are HIV negative and meet other selection criteria. Patients will be randomized to either Indinavir 800 mg by mouth 3 times daily or placebo. All patients will have clinical assessments, blood and urine test at baseline and every 3 months for 9 months. Both groups will have the option to consent to lumbar puncture for additional cerebrospinal fluid studies.
For more information about clinical trial contact: Theresa Imperato at 212-619-1400 at Beth Israel Medical Center or Maura Del Bene at 212-305-1319 at Columbia-Presbyterian Medical Center.
12th International Symposium on ALS/MND - November 18-20, 2001
Oakland California Highlights and Summary of Clinical Sessions
The International Symposium on ALS/MND is a unique annual event that brings together leading international scientific and clinical researchers and clinicians to present and debate key innovations in their respective fields. The clinical track features research and
advances in the care and management for people with ALS.
Preceding the Symposium, an Ask the Experts educational program addressed the latest in ALS research and clinical treatments for
patients and their families. Included in the presentations were discussions of the role genetics plays in ALS - and what additional
influence we may yet have to learn, stem cell research, immune/ inflammatory considerations, viruses and ALS, glutamate, Rilutek and
anti-oxidants and nutritional supplements. Different leaders in the ALS field presented an overview of the current status of each topic.
This year's clinical sessions were exciting and offered new information and interesting ideas to improve clinical care for people living with ALS.
Having a number of international presentations pointed out some of the striking differences in clinical care throughout the world. Two
examples are issues of patient autonomy and empowerment which, along with the quest for information about ALS, are clearly
prevalent in the U.S., but are much less common in other countries. The percentage of people with ALS living with long term mechanical
ventilation is 56% in Japan where the government pays for the necessary supportive care. Whereas, data from the ALS CARE database
suggest that as few as <2% of people with ALS in the U.S. have chosen mechanical ventilation.
Knowing when and how to evaluate a patient's respiratory status in the ways that will reliably identify the earliest signs of impaired
respiratory function are important. Non-invasive ventilation is a treatment for the respiratory weakness ALS can cause. This therapy
is probably the most significant treatment available to prolong life in ALS. There were a number of presentations on how best to analyze when non-invasive ventilation should be offered. Various tests of prognostic value were discussed recognizing that many patients with bulbar symptoms have trouble with ventilation tests. Nocturnal pulse oximetry measuring oxygen desaturation at night is emerging as an important indicator of respiratory status. The value of monitoring symptoms such as sleep disturbances, sleeping with the head raised, daytime yawning and sleepiness, and morning headaches as early indicators of respiratory impairment were stressed. There is broad variation among ALS clinics as to the numbers and percentages of ALS patients with feeding tubes - Percutaneous Endoscopic tubes (PEG). Despite the recommendation from the ALS Practice Parameter that PEG should be considered early in the course of ALS and begun before breathing function declines below 50% of predicted, the numbers of patients with PEGs vary from 0 to 50% of patients, depending on the clinic. Although it has been demonstrated that PEG can make a significant improvement in a person's nutritional and fluid status as well as quality of life, data to suggest an increase in survival are less clear. One study reported at this conference included data showing a slight trend to decreasing mortality with PEG.
Reports from three separate patient databases described long range experience with riluzole. All three reports suggest a trend of increasing survival with riluzole over time. More studies that are double blind and controlled are needed to confirm these database observations. The trend appears to indicate that longer periods of time than those used in the riluzole clinical trials may be needed to see the long-term survival advantage of the drug. An interesting observation was that despite the fact that the Irish government provides riluzole free of charge to people in Ireland with ALS, only two-thirds of the patients registered in the Ireland national ALS database reported taking riluzole.
Preliminary results of a small study (31 patients at three ALS clinics) of ultrapure creatine were encouraging in demonstrating a short-term trend of improvement in muscle strength. There was no change in scores on the ALS Functional Rating Scale that asks about level and independence in several activities of daily living. Findings from the initial study have led to a larger study that is now enrolling patients. The evaluation of the safety of Creatine showed no significant adverse drug effects. An overview of a project to improve end of life care for people
with ALS and their families stressed the need for better communication with patients from the time of diagnosis through the end of life, more research in this area and policy changes to improve hospice accessibility and other important care. The project is sponsored by the Robert Wood Johnson Foundation and is led by The ALS Association. Suggestions related to improving the efficiency of clinical trials were discussed including using the patient as his/her own control. While this design would ensure that each person in the clinical trial received the treatment, it is not totally blinded and the Food and Drug Administration has not supported this design. Although a single-arm trial design with the patient serving as his/her own control would require a longer study period than the conventional two-arm trial, up to eight times fewer patients would be required for this design than the placebo-controlled design. In the one-arm design, there is a period of no treatment that measures the patient's natural progression and a second period where the treatment is administered. Preliminary data from one German survey of 33 ALS patients and their partners suggest that the meaning and importance of sexuality does decline during the course of ALS, but its importance is still significantly underestimated by health care professionals. ALS clinicians should inquire about possible problems with sexuality and provide information, counseling and support as necessary.
Deep Vein Thrombosis (DVT) - blood clot in the blood vessels of the legs - and pulmonary embolism (PE) - blood clot in the blood
vessels of the lungs - are especially difficult to detect in people with ALS who have other reasons for limb swelling and difficulty breathing. As the consequences of these conditions can be life threatening, ALS clinicians may want to routinely include an assessment of these two conditions for their ALS patients - especially those who are elderly and/or have become immobile.
Caregiving for people with ALS was a continuing theme throughout many presentations recognizing the critical role families play in this disease. It was acknowledged that further analysis of ALS caregivers and support for this staggeringly difficult role must be a future emphasis.
Two reports of U.S. epidemiological studies in ALS emphasized the difficulty in conducting population-based research and in the
contributions well conducted epidemiological studies can make to understanding possible risks for the disease and, potentially, a
better understanding of the cause. A review of 22 years of deaths from ALS in Texas revealed that there is a suggestion of a slight
increase in the number of people dying from the disease. The increase was seen in the 6th and 7th decades of life in this retrospective review of death certificates. Over the 22-year period, 55% of the ALS deaths were in men and the median age at death for all people in the study was 68 years. The study did not find any evidence of an increasing incidence of ALS in younger people. There were several reports of ALS patients with various cognitive impairments - perhaps as many as 3-15% of all ALS patients. Clinician observance of cognitive changes in their ALS patients has been reported increasingly over the past few years. Examples of the types of changes that are described include memory loss, behavior changes, problems with both judgment and performing multiple tasks.
E. 12th International Symposium on ALS/MND November 18-20, 2001
Highlights and Summary of the Scientific Sessions
The International Symposium's research track bought together experts in the ALS field focusing on understanding disease mechanism and testing therapeutic approaches for ALS. Although the exact disease mechanism in ALS remains unclear, many new hypotheses have been proposed and in some cases, "old" hypotheses are being revisited. What is clear is that disease is likely to be multifactoral and not limited to the motor neurons. Surrounding cells such as microglia and astrocytes are likely to be involved too. With an increased number of disease hypotheses and the availability of a mouse model for ALS, the number of compounds being tested for possible therapies for ALS is escalating and some promising findings were presented. The research presentations can be broadly divided into three key topics detailed below.
1. Disease Mechanism:
Cell Death PathwaysThere is a fine balance between the death and survival of motor neurons throughout their lifetime. This is particularly evident during embryonic development. An average of 50% of the motor neurons initially generated die just after they have contactedtheir target muscle. The reason for this is unknown although key players involved in this death pathway are continually being identified. What is not known is whether the pathways involved in embryonic development are similar to those leading to neuron degeneration in adulthood. In an ALSA-funded study as part of the Lou Gehrig Challenge: Cure ALS Campaign, Dr. Chris Henderson and his group are studying purified motor neurons in culture and identifying the key players involved in these "death pathways." Their studies show that not all motor neurons respond in the same way to external stresses and indeed, motor neurons isolated from transgenic mice expressing mutant SOD1 showed increased sensitivity to stimulation of a cell surface receptor called Fas. Activation of this receptor leads to down stream signaling events and activation of cell death pathways. Dr. Dale Bredeson and colleagues described different types of cell death and emphasized the importance of understanding these pathways when thinking about interventions.
SOD1 and Motor Neuron Degeneration
With the discovery of mutations in the SOD1 gene linked to 20% of familial ALS cases nearly a decade ago, it seemed likely that disease mechanism for a portion of ALS cases would be solved and would help in understanding sporadic ALS as clinical and pathological features for both forms of the disease have been reported to be similar. How mutations in SOD1 cause the disease is certainly not resolved although oxidative damage, excitotoxicity, mitochondrial damage, abnormal accumulation of SOD1 protein are all possible mechanisms leading to motor neuron death. Dr. Zuoshang Xu presented his recent data showing that SOD1 protein is present in the inner membrane space surrounding the mitochondria (organelles that are important energy sources for cells and highly enriched in axons of neurons). Several studies have described abnormal mitochondria in transgenic mouse models of ALS. Dr. Xu's studies will determine how mutant SOD1 leads to mitochondrial damage. This project has just been approved for ALSA funding commencing in February 2002.
Motor Neurons, Astrocytes and Microglia
Research has largely focused on the motor neurons and why they die. Recently published data has shown that they are not the only cells affected and that astrocytes (surrounding the neurons) are also abnormal. Dr. Don Cleveland described ongoing studies in his lab in which mice were generated with varying proportions of normal and mutant cells (containing the SOD1 mutations), termed chimeric mice. Similar studies as part of ALSA's Lou Gehrig Challenge Initiative, are ongoing in Dr. Robert Brown's laboratory. This investigation set out to ask whether cells with the mutant protein could transfer toxicity to surrounding normal cells. Early results indicate that they indeed can transfer their toxicity (further studies are required to confirm this finding). In addition, early findings indicate that increasing the number of normal cells surrounding neurons carrying the SOD1 mutation, improves the survival of these neurons. This encouraging data indicate that introducing cells via stem cell therapy may improve the surrounding environment for the dying neurons and slow their degeneration. Dr. Janice Robertson described exciting results implicating Microglia in the cell death of motor neurons. Microglia are the immune cells of the brain. Dr. Roberstson's has been awarded an ALSA grant to further these studies which will commence in February 2002. The idea that inflammation may be involved in disease is receiving much attention and is an example of an "old" hypothesis revisited.
Heat Shock Proteins and Protein Folding
Abnormally accumulated mutant SOD1 is seen in transgenic mice expressing mutant SOD1 (and in particular in the G85R mutant mouse). Whether these aggregates lead to motor neuron and glial damage or whether they are innocent bystanders is debated amongst researchers. Dr. Heather Durham presented results from her ALSA-funded study, to understand why motor neurons are vulnerable and how these aggregates may lead to cell death. Heat shock proteins/stress proteins are normally upregulated to aid in the removal of abnormal protein aggregates. The presence of protein aggregates in familial and sporadic ALS suggests that there may be a failure of motor neurons to upregulate the stress proteins. Studying motor neurons in culture, Dr. Durham showed that motor neurons do not upregulate heat shock proteins, and may therefore be less efficient at removing abnormally accumulated protein accounting for these protein aggregates.
Excitotoxicity, Calcium Influx and Zinc
Excessive glutamate levels leading to a mechanism termed "excitotoxicity" have been implicated as a common mechanism for neurodegenerative diseases. Excessive glutamate leads to activation of glutamate receptors, a flooding of the cell with calcium, and a host of damaging downstream events. Dr. Dennis Choi, a leader in this field gave an eloquent presentation on excitotoxicity and cell death, highlighting that zinc might specifically promote motor neuron death, encouraging
investigators to consider novel therapeutic approaches to limit zinc-induced excitotoxicity.
An abundant glutamate transporter in astrocytes (cells
surrounding the neurons) known as EAAT2, involved in the removal of excess glutamate, is decreased in cortex and spinal cord of patients with ALS and in mouse models of ALS expressing mutations in SOD1 linked to familial ALS. (Indeed, dramatic reduction of the transporter is also described in a new rat model of ALS developed as part of ALSA's Lou Gehrig Challenge: Cure ALS Initiative (Please see rat SOD1 article on the ALSA web site "In the Spotlight" section.). Studies focusing on the role of glutamate transporters and cell death, many led by Dr. Jeffrey Rothstein and colleagues, were not presented at the symposium but were presented at the Society for Neuroscience Annual Meeting in November in San Diego.
In an ALSA-funded study, Dr. Margaret Sutherland and colleagues
at George Washington University, in collaboration with Dr. Jeffrey Rothstein at Johns Hopkins University, demonstrate that increasing levels of this glutamate transporter in a mouse model of ALS is neuroprotective. Mice expressing high levels of EAAT2 were bred to mice expressing mutant SOD1. Disease onset was delayed by about one month, increasing the life span of the mice by approximately 25%.
New Avenues for ALS Research: Vascular Epithelial Growth Factor
(VEGF) and Erythropoeitin. The discovery that VEGF is in any way linked to motor neuron degeneration came as a complete surprise. VEGF is a family of growth factors involved in blood vessel development and expressed in lymphatic and cardiac vessels. This factor is highly regulated by oxygen levels. Development of a mouse in which a region of the VEGF gene sensitive to oxygen levels was deleted, resulted in decreased levels of VEGF and a mouse with motor neuron degeneration. This study was the first indication that this factor may in some way be involved in motor neuron degeneration. Dr. Wim Robberecht described these studies and as part of an ALSA-funded study is currently investigating the role of VEGF in motor neuron survival. Interestingly, Dr. Bendotti described their studies of rythropoetin, a hormone produced by the kidney in response to low oxygen levels. These independent studies raise interesting questions about tissue oxygenation and ALS.
Therapeutic Approaches using Mouse Models of ALS
Although the discovery of SOD1 mutations has been less promising than originally hoped in defining the disease mechanisms involved in motor neuron death in ALS, it has lead to the development of a model for ALS. Mice expressing mutant SOD1 G93A have become the "gold standard" to test therapies for ALS. Several such studies were presented.
Minocycline is an antibiotic thought to act on a cell death pathway by blocking caspase 1 (a protease involved in this "death-pathway"). Dr. Wim Robberecht and colleagues reported delayed onset of disease and an increase in lifespan of transgenic mice expressing mutant G93A SOD1. The exact mechanism is unclear and studies are ongoing to address this.
The use of a viral delivery system to administer growth factors such as GDNF (factors important for the development and survival of neurons) and other factors important for supporting motor neurons has been the focus of several research groups over the past years. Two key challenges to using gene therapy as a therapeutic approach are firstly, the choice of the appropriate delivery system (viral vector) and secondly, the route of administration. Dr. Wang and colleagues described their efforts delivering the viral vector to the muscle. The growth factor is produced in the muscle and transported to the spinal cord motor neurons. In a similar study, Dr. Acsadi described improved motor function in transgenic mouse models of ALS after administration of virally expressed GDNF in the muscle. The viral vector is injected at a very early stage in the mouse, well before motor neuron degeneration. It remains untested whether this approach would be effective at the time of disease onset and whether GDNF levels are sufficiently maintained over extended periods of time.
Stem Cell Therapy
Efforts to determine whether stem cells derived from various tissues such as umbilical cord blood or embryos increase the lifespan of transgenic mouse models of ALS are in early stages. These efforts are crucial to determine the feasibility of stem cell therapy for ALS. Many issues are currently being addressed by researchers: the source and number of stem cells required to show improved motor function, the earliest time point stem cells need to be administered to show an effect, problems with immune rejection, what cell types are found after stem cell administration and the extent of delayed disease onset and increased survival. Dr. Robert Brown and colleagues shared their ongoing studies in this area.
EPO, as described in Section 1, is a hormone produced by the kidney in response to low oxygen levels. EPO was administered to pre-symptomatic mutant SOD1 mice and disease onset and progression were delayed. It is unclear whether these effects are due to improved tissue oxygenation or a neuroprotective effect of EPO.
Tamoxifen and Celebrex
Two other studies looking at the effects of Tamoxifen and Celebrex on mouse models of ALS were not discussed at the symposium, but were presented at Society for Neuroscience Annual Meeting. For further details of this study please see Drug Development section of the ALSA web site under "Research."
3. New TechnologiesProteomics
Dr. Chris Shaw gave a detailed and clear presentation of what Proteomics is and how this technology will be useful in identifying therapeutic targets. Techniques to look at protein changes are not new and have been a part of research for years. Proteomics, the study of protein changes in study samples (human tissue, culture systems, animal models) enables large numbers of protein changes to be described in a very efficient manner and relies on computer technology to interpret the data. Protein changes included changes in levels of expression as well as protein modifications such as an addition of phosphate, tyrosine and nitrate groups to the native protein. These protein modifications may be important for normal function or could indicate abnormal processes. Several laboratories are exploring this area of research and as the technology improves this will be an invaluable tool that will eventually lead to the identification of drug targets.
High-throughput Cell Based Assays for ALS
To screen large numbers of compounds that may be useful for therapy in ALS in a short period of time it would not be feasible to use the animal model of ALS. The first step to finding suitable compounds amongst a large collection of compounds would be to develop a system that can rapidly determine those compounds that are promising. This has led to the development of model systems (assay system) in 384 well plates to which drugs are added by means of sophisticated robotic systems. The most important aspect of setting up such a system is the development of appropriate models to be tested. Dr. Qing Liu, funded under ALSA's Lou Gehrig Challenge Initiative, described her assay system and the results from initial screens. She is looking for compounds that will prevent the development of SOD1 aggregates, described in the section "disease mechanism," as one of the possible ways that motor neurons are dying.
Dr. Chris Henderson described the model system that Trophos, a biotech company in Marseille, France has developed where they isolate and maintain motor neurons in 384 well plates, stress these cultures and then look for compounds that under these stress conditions protect the motor neurons. Once interesting compounds have been found in either of these assays, they can be tested in mouse or rat models of ALS.
F. NEW STUDIES AT THE UNIVERSITY OF MIAMI NEUROLOGY DEPARTMENT
Contact Person: Julie Steele, LPN, CCRC
(305) 243 7526
This study of the nutritional supplement "creatine" is still looking for individuals to participate. The study is 6 months in length, some participants will receive creatine 5 gms/day and some will receive placebo (like a sugar pill).
The objective of this study is to determine whether creatine slows disease progression in ALS. Creatine, an agent that improves mitochondrial function, has been shown to be neuroprotective in animal models of ALS.
This study is no enrolling participants.
The blinded phase of this study completed some time ago. The company, Sanofi-Synthelabo is submitting data to the FDA, no information regarding the status is available. The medication, xyloproden, continues to be supplied to those who participated in the blinded phase of the study. The drug is not allowed to be dispensed to anyone else until FDA approval.
This study of a compound dexomethorphan/quinidine is still looking for individuals to participate. The study is 1 month in length, will determine if this compound is effective in treating a symptom, which some ALS patients have called "pseudobulbar affect". This symptom is characterized by uncontrollable outbursts of laughing or crying.
The study enrollment should start January or February 2002. A study to determine if the initiation of BiPAP (Bi-level Positive Air Pressure) is more beneficial for ALS patients if begun earlier than the standard treatment.
BiPAP is used to assist patients with their breathing when they become short of breath. BiPAP is done by placing a mask over the patient's nose and pushing air into their lungs. Currently, Medicare does not allow reimbursement for BiPAP until the patient's forced vital capacity (a measurement of breathing strength) falls to half of what it normally should be. Arrangements have been made with a local respiratory company to supply the equipment.
Enrollment to begin early February.
Some paperwork is pending.
No longer enrolling participants.
Here is good example of why placebo groups are an important part of research. This study was terminated when the group that was receiving the drug had more serious (life-threatening) side effects than the placebo group. This information would not have been available if a placebo group was not part of the research.
The objective of this study is to determine whether topiramate slows disease progression in ALS.
The data from this study continues to be reviewed to determine the effectiveness.
Not seeking donors at this time.
The University of Miami is collecting brain and tissue samples from ALS patients. The tissue is used for current and future research.
Familiar ALS Study
This genetic study is looking for possible genes that may be associated with ALS. The participants are selected when there is a known family history of ALS. The study involves collecting blood samples and consulting with a genetic counselor.
We believe that a "full service" ALS Center needs to provide: (1) the highest level of diagnostic skills, so that no patient with a treatable disease mimicking ALS is missed; (2) the best clinical care possible; (3) research into the cause and cure of ALS; and (4) research into the way to improve the management of patients with ALS. We hope that we can continue to provide all of these through the Kessenich Family MDA ALS Center of the University of Miami.