MGH 2000 ALS update

 

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Below please find a copy of Massachusetts General Hospital's and Harvard Medical School's 2000 ALS research update.  The Curtis R. Vance Foundation, Inc. is pleased to have donated to their program.  The information was supplied to the foundation by Robert H. Brown, Jr., Director of the Cecil B. Day Laboratory and Professor of Neurology (dated February 28, 2001).

 

I.    Stem Cell Transplantation Studies - Steve Kalkanis, MD  

    Over the last year, we have devised a stem cell transplantation project to test the hypothesis that stem cell and fetal neuronal cells delivered both into the spinal cord and systemically will ameliorate motor neuron cell death in a mouse model of ALS.
    The cells presently employed in this project include systemically delivered human umbilical cord blood cells and fetal pig spinal cord cells.  We will also use neural stem cells as they become available.

      (A) Systemically delivered human umbilical cord blood cells

   In spring, 2000, Dr. Normal Ende reported that large boluses of human umbilical cord blood stem cells injected systemically into ALS SOD1g93A mice pretreated with sublethal radiation and subcutaneous anti-killer sera both (a) rescues the mice from radiation death and (b) prolongs survival from motor neuron disease in a fraction of the mice.  Strikingly, some of the animals achieved a 40% increase in lifespan.  We have collaborated with Dr. Ende to repeat his initial experiments.  These pilot experiments were designed to determine whether we could reproduce the survival effects and ascertain which cell types are implicated.

      (B) Intraspinally delivered fetal pig spinal cord cells

    The second, parallel phase of our project has involved a local, intra-spinal injection of a small sample of fetal porcine spinal cord progenitor cells into immunosuppressed ALS mice.  These studies address the potential for stem cell transplantation to ameliorate the motor neuron death process.

II.    ALS Drug Discovery Program - Piera Pasinelli, Ph. D.

    Over the last three years, Piera Pasinelli has conducted a series of experiments to characterize the cell death process triggered by mutant SOD1 protein.  These studies have lead to the observation that oxidatively triggered cell death mediated by mutant SOD1 entails sequential activation of programmed cell death genes known as caspases 1 and then 3.  A by-product of Dr. Pasinelli's work has been the development of assay systems that allow one to screen for compounds that ameliorate the cell death mediated by mSOD1.  These different systems employ different methods to mimic ALS in cells in a Petri dish.

    The quantification of cell viability that is based on the measurement of fluorescence generated from cleavage of calcein-ester to calcein by intracellular esterase, abundant in living cells.  The fluorescence emitted by the living cells can easily be quantified using a fluorimeter.
    Our initial studies of apoptotic cell death mediated by mutant SOD1 used differentiated N2A cells.  With one assay, we have collaborated with Dr. Steve Gullans to screen a library composed of all the ~1200 or so drugs approved for human use by the Food and Drug Administration.  Eleven of these were protective in our simply assay.  We divided these compounds in major categories based on their mechanisms of action.

    Our intent in the next several months is to apply this assay to a larger library of compounds, rather than just the 1,200 FDA-approved compounds.  From the standpoint of applied therapeutics, our intention is to characterize any hits in detail and then to examine the feasibility of using the compound in mice or even human trials.  From the view of the basic biology of SOD1, we anticipate that these studies will be a powerful approach to probing mechanisms and pathways of cell death.  This information alone may point to candidate treatment strategies.

III.    Human and Mouse Drug Trials - Merit Cudkowicz, M.D.

    Dr. Merit Cudkowicz has developed and continues to run a large clinical trials unit dedicated to rapid, accurate execution of drug trials in ALS patients.  This is built around the ALS Clinic and the MGH and Partners Neurology Clinical Trials Unit at the MGH.  At the MGH we now follow approximately 200 subjects with ALS.  Increasingly, Dr. Merits group now also encompasses a clinical trials group founded by Drs. Cudkowicz and Brown (at the M.G.H.) and Dr. Jeremy Shefner (at Syracuse University) to facility rapid drug trials.  This group, the Northeast ALS group or NEALS, has met several times in the last two years and is now conducting its first ALS trials.

    A list of our currently active clinical trials in ALS includes the following:

1. Topiramate.  MGH is Coordination Center for this 20 center clinical trial involving 288 subjects.  This is the first NIH funded clinical trial in ALS.  Enrollment for this study was completed in 12 months; results are expected in August 2001.

2. Creatine.  MGH is the Co-Principal Investigator with Dr. Shefner.  This is an 18 center clinical trial.  All data management and analysis are at the MGH.  The trial started 11/2000.  It is MDA sponsored.

3. Buspar.  This study is conducted by MDA and Johns Hopkins University, and was prompted by funding by Project ALS.  Approximately 16 subjects have enrolled to date of the target of 50.

4. Dextramethorphan/quinidine.  This compound is being tried in a small study as a measure to help manage emotional liability ("pseudobulbar affect") in ALS.  This trial, which has just started, is industry sponsored.

5. Intrathecal BDNF.  This 20 center clinical trial is industry sponsored.  The double-blind portion of study is completed.  It is now in open-label.  The MGH enrolled 20 subjects.

6. Subcutaneous BDNF.  This is an industry-sponsored, 20 center clinical trial.  The study will be completed in March 2001; results are expected in June 2001.

    We have previously completed clinical trials of the following drugs and therapies in ALS: of Procysteine, a small molecule anti-oxidant; SOD1, infused by pump into the spinal fluid, and a cocktail of multiple antioxidants.  

    A clinical trial of Celebrex will begin in the near term.  This study will be conducted jointly run by the MGH and Johns Hopkins University.  It is a 21 center clinical trial involving 300 subjects.  The anticipated start date is June, 2001.  Funding for this has been requested via an NIH grant submitted by MGH 2/1/01.  Funding is also requested from the MDA. 

    In parallel with human drug trial program, Dr. Merit Cudkowicz has collaborated closely with Dr. Brown to test more than 20 different manipulations for possible benefit in the ALS SOD1 mice.  These include the following drug therapies: penicillamine (a copper binding drug), procysteine (an antioxidant), penicillamine plus procysteine, diethyldithiocarbamate (another copper binding agent), selenium (used as an anti-oxidant), nerve sprouting proteins known as neurophillins, inhibitors of the enzyme nitric oxide synthase, FGF (fibroblast growth factor, a protein growth factor for nerves), and several other small molecule anti-oxidants.  We have also tried genetic manipulations that turn off the cell death gene caspase-1, express high levels of glutathione peroxidase, an anti-oxidant enzyme, inactivation (genetic), shut down glutathione peroxidase, and shut down endothelial nitric oxide synthase.

    Outcomes have typically been disease onset and survival.  Of these several trials, only two or three have shown any benefit and this has been marginal.  Nonetheless, we have in place the infrastructure fully to characterize the disease process in the ALS SOD1 mice, and the impact of therapy on the animals.  Moreover, we are confident that when we have successful therapy in the mice we also have the infrastructure required to move quickly to human trials.

IV.     Genetic Investigations - Robert H. Brown, Jr., D.Phil., M.D.

    The Day Lab has continued the program to discover new ALS genes in the expectation that information about new ALS genes will provide fresh insight into pathways and mechanisms for the cause of ALS.  Moreover, as in the case of SOD1, new genes may be powerful routes to developing new animal and cell models of ALS.

    Our collection of families with inherited ALS now numbers nearly 500.  Of these, only about 25% arise from mutations in the SOD1 gene.  Over the last year, we have continued to accession new families into our study population.  We now have 490 total ALS pedigrees.  We have used conventional linkage analysis to screen for new ALS gene addresses in a core data set of 16 non-SOD1 ALS pedigrees.  As reported in the Journal of the American Medical Association last fall, we found one new address for a form of ALS that is associated simultaneously with a very striking type of dementia (fronto-temporal dementia).  The characteristic behavioral features of this form of dementia are disinhibited behavior and cognitive disturbance with relative preservation of memory. 

    In the other 14 non-SOD1 ALS families we have almost completed a full screen of the human genome for more linkage.  We believe we have found at least two new ALS loci during this process.  Unfortunately, each is linked to only one family.  The great disadvantage of this is that we therefore will have difficulty narrowing down the gene's exact address.  When the chromosomal address is not narrowed, the search for ALS genes is extremely laborious, because one must screen literally scores of genes in the candidate region.

    In addition to the above, adult-onset ALS families, we have been studying a childhood onset of ALS.  We have been able to refine genetic linkage analysis of the 2q33 locus using several new polymorphic markers.  This has narrowed the locus to approximately 1.7 million bases.  Dr. Hosler in our group has collaborated with Dr. Chenyan Wu to fully clone this locus in phage artificial chromosomes.  With this clone set, they have identified approximately 30 candidate genes in the locus.  Dr. Tom Kwiatkowski in the group is now in the process of sequencing these genes using an automated sequencer.

    Through the auspices of Dr. Peter Andersen in Umea, Sweden, and Dr. Lars-Gunnar Gunnarson in Copenhagen, we have also been investigating three very large families with inherited ALS and dementia.  These studies have proceeded smoothly over the last two years.  We are cautiously optimistic that new loci and ultimately genes will emerge from these investigations.

    Finally, Dr. Mac Ho in our group has been investigating very new approaches to deactivating genes like SOD1 whose mutant forms can trigger ALS.  In the long-term, we believe that this will be a profound and powerful strategy to treat inherited forms of ALS and related neurodegenerative diseases.

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