Israel Medical Association Journal

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive death of motor neurons leading to fatal paralysis. The causes of ALS remain unknown; however, evidence supports the presence of autoimmune mechanisms contributing to pathogenesis. Although several environmental factors have been proposed, the only established risk factors are older age, male gender, and a family history of ALS. To date, there are no diagnostic test for ALS, and clinicians rely on the combination of upper motor neuron and lower motor neuron signs in the same body region. The aim of this paper was to provide a comprehensive review of current clinical literature with special focus on the role of autoimmunity in ALS, differential diagnosis, and available therapeutic approaches. Current evidence suggests a contribution of the innate immune system in ALS, with a role of microglial cell activation at the sites of neurodegeneration. The median time from symptom onset to diagnosis of ALS is 14 months, and this time estimate is mainly based on specific clinical signs and exclusion of ALS-like conditions. Several therapeutic approaches have been proposed, including immunosuppressive drugs, to reduce disease progression. Riluzole has been established as the only, although modestly effective, disease modifying therapy, extending mean patient survival by 3to 6 months. Recent advances in understanding the pathophysiology mechanisms of ALS encourage realistic hope for new treatment approaches. To date, the cornerstones of the management of patients with ALS are focused on symptom control, maintaining quality of life and improving survival.

Although the free radical theory of aging is widely accepted among scientists, the possibility of using antioxidants to delay the aging processes seems to encounter considerable skeptism among clinicians. This may be, at least in part, due to lack of knowledge about the basic chemistry and biological behavior of oxidative stress, antioxidants, and the complex interactions between them. However, one cannot ignore the explosive growth of information concerning the mechanisms underlying the processes of aging, their consequences, and the use of antioxidants in suppressing such effects. In order to provide patients with the most accurate information regarding the use of antioxidant supplementation in their diet, it is important to obtain basic data regarding oxidative stress and antioxidants. This article explores the role of oxidative stress in the aging phenomena, recent evidence supporting supplementation of antioxidants for aged people,  the ability of antioxidants to prevent or retard cancer and atherosclerosis (the major causes of mortality in the aged population), and the ability of antioxidant supplementation to delay age-dependent deterioration of cognitive function. Based on the data presented, we conclude that current knowledge provides insufficient and inconclusive support for antioxidant supplementation as a means of delaying aging processes, despite the encouraging results obtained in many studies.

Between the 1960s and 1980s, the main focus of biological research was nucleic acids and the translation of the coded information into proteins. Protein degradation was a neglected area and regarded by many as a scavenger, non-specific and end process. While it was known that proteins are turning over, the large extent and high specificity of the process - where distinct proteins have half-lives that range from a few minutes to several days - have not been appreciated. The discovery of the lysosome by Dr. Christian de Duve did not change this view significantly, as this organelle is involved mostly in the degradation of extra- and not intracellular proteins, and it was clear that lysosomal proteases, similar to those of the gastrointestinal tract, cannot be substrate specific. The discovery of the complex cascade of the ubiquitin pathway has changed this view dramatically. It is now clear that degradation of cellular proteins is a highly complex, temporally controlled, and tightly regulated process that plays major roles in a broad array of basic pathways during cell life and death. With the multitude of substrates targeted and processes involved, it is not surprising that aberrations in the pathway have been recently implicated in the pathogenesis of many diseases, certain malignancies and neurodegeneration among them. Degradation of a protein via the ubiquitin pathway involves two successive steps: a) conjugation of multiple ubiquitin moieties to the substrate, and b) degradation of the tagged protein by the downstream 263 proteasome complex with release of free and re-utilizable ubiquitin. Despite intensive research, the unknown still exceeds what we currently know on intracellular protein degradation and major key problems remain unsolved. Among these are the modes of specific and timed recognition of the myriad substrates of the system and the nature of the mechanisms that underlie aberrations in the system and pathogenesis of diseases.