ALS (Amyotrophic Lateral Sclerosis)
The degeneration and ultimate death of neurons that control muscles is a hallmark of amyotrophic lateral sclerosis (ALS), a rare, progressive neurodegenerative motor neuron disease (MND). 1 Motor neurons, specialized nerve cells, innervate muscles through signal transduction pathways. ALS causes damage to motor neurons in the brain, brainstem, and spinal cord. Nerve cell destruction via apoptosis or other forms of cell death during the progression of ALS results in loss of muscle innervation, which is accompanied by muscle atrophy and degeneration.
Connections or signal transduction pathways between the nerve cells and the muscles they support are progressively disrupted, broken and lost. As a result, individuals with ALS become progressively weaker or paralyzed as nerve cells nourishing and sustaining the affected muscles are lost and muscles atrophy.
The name of the disease, amyotrophic lateral sclerosis, is derived from a combination of three words:
- 1. Amyotrophic is derived from the Greek word 'amyotrophia,' meaning lacking muscle nourishment and sustenance.
- 2. Lateral is the area of the spinal cord damaged by ALS
- 3. Sclerosis comes from the Greek word 'sklerosis' derived from 'skleroun' meaning harden, and refers to the stiffness and tightness of the limbs caused by continuous muscle contractions characteristic of ALS.
The initial symptoms of ALS are related to atrophy or muscle weakness. They may be subtle, vary from person to person and include stumbling, tripping, dropping things, excessive arm or leg fatigue, or slurred speech. Labile emotions such as uncontrollable crying or laughing have also been described. ALS is extremely rare, and the diagnostic odyssey can be rather arduous because other masquerading conditions or explanations often must be ruled out before ALS is formally diagnosed. 1, 2
The etiology or cause of nerve cell destruction in ALS remains to be fully elucidated. 1-3 However, it is increasingly becoming clear that ALS is a heterogeneous, multisystemic and multifactorial disease. For example, historically it was thought cognitive function was almost always preserved in ALS. Now there is emerging evidence that frontotemporal dysfunction or degeneration also known as frontotemporal lobe dementia (FTD)) may play a more significant role in ALS pathology than previously recognized.2 FTD is associated with cognitive and behavioral symptoms, it is estimated that 30% to 60% of individuals with ALS have at least some cognitive impairment.3
The current dogma is that ALS may develop from interactions between genetic and environmental factors and scientists know ALS is not a single disease entity.3 There are many theories and proposed mechanisms. For example, mutations in the SOD1 (superoxide dismutase) enzyme may account for up to 15% of familial cases of ALS. 2 SOD1 has been implicated in both ALS and apoptosis and more than 100 mutations in SOD1 have been described. 2 From a mechanistic standpoint, it has been suggested that activation of caspase enzymes may lead to destruction of motor neurons in ALS. 1 Death signals are thought to start in the cell body and then travel down the nerve fibers. 1 Caspase activation is the hallmark of apoptosis and caspases also function in necrosis and inflammation which are also processes associated with cell death.
ALS is also called Lou Gehrig's disease after the famous baseball player Lou Gehrig who played first baseman for the New York Yankees and died of the disease in 1941. Lou Gehrig's death shone a spotlight on ALS. The Muscular Dystrophy Association (MDA) was founded in the 1950's and began providing funding for ALS research. Today advocacy groups are helping to spur research through fund raising activities such as the acclaimed ALS Ice Bucket Challenge. The Ice Bucket Challenge held in the summer of 2014 brought unprecedented awareness and donations to support the fight against ALS.
Related Research Reagents:
- Human SOD1 Superoxide Dismutase 1, Soluble, ELISA Kit (Catalog #MBS083610)
- Rat SOD1 Superoxide Dismutase 1, Soluble. CLIA Kit (Catalog #MBS2532786)
- Human SOD1 Superoxide Dismutase 1 Recombinant Protein (Catalog #MBS717289)
- Caspase-3 (Pro and Active) Monoclonal Antibody (Catalog #MBS668032)
- ApoMark Apoptosis Kit, IHC Kit (Catalog #MBS396367)
- Aposcreen Annexin V Apoptosis, Flow Cytometry Kit (Catalog #MBS679231)
- 1. Morris J. Amyotrophic lateral sclerosis (ALS) and related motor neuron diseases: an overview. Neurodiagn J 2015 DOI:10.1080/21646821.2015.1075181.
- 2. Rosenfeld J, Strong MJ. Challenges in the understand and treatment of amyotrophic lateral sclerosis/motor neuron disease. Neurotherapeutics 2014 DOI:10.1007/s13311-014-0332-8.
- 3. Lacorte E, Ferrigno L, Leoncini E et al. Physical and physical activity related to sports, leisure and occupational activity as risk factors for ALS: A systematic review. Neurosci. Biobehav. Rev. 2016. doi:10.1016/j.neubiorev.2016.04.007