MEDICINE PLAYING DEFENSE AGAINST LOU GEHRIG S DISEASE Amyotrophic lateral sclerosis ALS is a disease that kills motor neurons Patients become paralyzed and usually die within three to fi ve years of onset The most famous victim is legendary New York Yankees player Lou Gehrig below ALS was once considered nearly impregnable to a scientific attack but researchers have recently discovered treatments that can slow the progress of the disease in rodents by protecting the axons of motor neurons Investigators are now preparing clinical trials to test the effec tiveness of the proposed ALS treatments in humans The 86 Editors SCIENTIFIC AMERICAN Researchers have proposed potential therapies for a paralyzing disorder once thought to be untreatable By Patrick Aebischer and Ann C Kato T he official name of the illness is amyotrophic lateral sclerosis ALS but in the U S it is better known as Lou Gehrig s disease The great New York Yankees first baseman was diagnosed with ALS in 1939 and died of the Persian Gulf War and residents of the istwo years later from the progressive neuromus land of Guam although no one knows why In his famous farewell address at Yankee Stacular disorder which attacks nerve cells that lead from the brain and the spinal cord to mus dium Gehrig called ALS a bad break which cles throughout the body When these motor was a heartrending understatement People usuneurons die the brain can no longer control ally succumb to the disease within three to five muscle movements in the later stages of the dis years after diagnosis A notable exception is Stephen Hawking the renowned physicist of the ease patients become totally paralyzed First described in 1869 by French clinician University of Cambridge who has lived with Jean Martin Charcot ALS is a misunderstood ALS for more than 40 years and is still making illness Doctors once thought it was rare but now major contributions to the fields of cosmology consider it fairly common about 5 000 people in and quantum gravity despite his physical handithe U S are diagnosed with ALS every year In cap Until recently investigators had few practitotal there are about 30 000 ALS patients in the cal ideas for fighting the disorder but in the past U S and approximately 5 000 in the U K ALS several years researchers have made great protypically develops between the ages of 40 and 70 gress in determining how motor neurons die in but the disease strikes younger and older pa ALS patients In the near future scientists may tients as well Other well known people who develop therapies that could retard the progress suffered from ALS include British actor David of ALS and perhaps even prevent its onset Niven Russian composer Dmitri Shostakovich and Chinese leader Mao Tse tung Researchers A Devastating Disorder have found unusual clusters of patients with the You can glean a basic understanding of amyodisorder among Italian soccer players veterans trophic lateral sclerosis by parsing its name November 20 07 AP CREDIT PHOTO KEY CONCEPTS BRYAN CHRISTIE DESIGN Amyotrophic is an amalgam of Greek terms a for negative myo for muscle and trophic for nourishment Putting it all together the word conveys that the muscles in an ALS patient have no nourishment so they atrophy or wither away Lateral signifies the area of the spinal cord where portions of the dying nerve cells are located As this area degenerates it becomes hardened or scarred Sclerosis means hardening Perhaps the most devastating aspect of the illness is that the higher functions of the brain remain undamaged and patients are obliged to watch the demise of their own bodies The most common form of the disease is called sporadic ALS because it appears to strike randomly targeting anyone in any given place Familial ALS is a particular form of the disease that is inherited but only about 5 to 10 percent of all patients fall into this category Although the early symptoms of the disorder vary from one individual to another they usually include dropping objects tripping unusual fatigue in the arms or legs difficulty in speaking muscle cramps and twitches The weakness that affects ALS patients makes it hard for them to walk or use their hands for daily activities such as washing and dressing The disease eventually hampers swallowing chewing and breathing as the weakening and paralysis spread to the muscles in the trunk Once the muscles responsible for breathing are attacked the patient must be put on a mechanical ventilator to survive Because ALS harms only motor neurons the senses of sight touch hearing taste and smell DYING BACK One of the key breakthroughs in the fight against ALS is the finding that the degeneration of the motor neurons begins at the ends of the axon the nerve cell s main branch and proceeds back to the cell body are not affected For unknown reasons the motor neurons responsible for movements of the eyes and bladder are spared for long periods Hawking for example still has control of his eye muscles at one time he communicated by raising an eyebrow as an assistant pointed to letters on a spelling card He can also move two fingers on his right hand and now uses a speech synthesizer controlled by a hand switch The U S Food and Drug Administration has so far approved only one treatment for ALS riluzole a molecule that can prolong survival by several months most likely by curbing the release of harmful chemicals that damage motor neurons What do we know about the causes of this horrible disease Investigators have put forward a vast number of theories to explain its origin including infectious agents a faulty immune system hereditary sources toxic substances chemical imbalances in the body and poor nutrition Although scientists have not yet determined what triggers the disorder in most patients a breakthrough came in 1993 when a consortium of geneticists and clinicians discovered a gene that was responsible for one form of hereditary ALS that represents approximately 2 percent of all cases This gene turned out to code for an enzyme called superoxide dismutase SOD1 that protects cells from damage caused by free radicals highly reactive molecules produced SCIENTIFIC AMERICAN 87 in the body by normal metabolic processes posed over the years to explain how ALS arises We are beginning to understand that the moResearchers subsequently identified more than 100 different mutations in the SOD1 gene tor neuron may have a novel mechanism for deALS was once thought to be rare that cause ALS It remains a
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