[Update on fundamental and clinical research in amyotrophic lateral sclerosis]

Neurofilament heavy subunit in cerebrospinal fluid: a biomarker of amyotrophic lateral sclerosis?

The objectives of this study were to investigate the presence of the three neurofilament subunits, ubiquitin, proteasome and 3-nitrotyrosine, in CSF samples of ALS patients. CSF samples were obtained by lumbar puncture from 10 ALS patients and six controls. All samples were analysed by Western blotting. Results revealed that neurofilament heavy subunit was identified in 70% of ALS cases and we conclude that this subunit may be a promising biomarker for clinical diagnosis of ALS.

[Research in amyotrophic lateral sclerosis: what is new in 2009?]

This paper, written by French amyotrophic lateral sclerosis (ALS) center experts, presents an update of recent advances in fundamental, epidemiological and clinical research in ALS based on a review of the literature between September 2008 and November 2009. Among other pathophysiological mechanisms, the role of stress of the endoplasmic reticulum and the importance of energetic metabolic disturbances have been underscored. In the field of genetics, research has been advanced through the identification of mutations of the gene FUsed in Sarcoma/Translated in LipoSarcoma (FUS/TLS) in individuals with familial and sporadic ALS. This gene is involved in the regulation of transcription, splicing and RNA transport, and has functional homology to another ALS gene, TARDBP, which suggests that a common mechanism may underlie motor neuron degeneration. A report showed that mice expressing a mutant form of human TDP-43 develop a progressive and fatal neurodegenerative disease reminiscent of both ALS and frontotemporal lobar degeneration with ubiquitin aggregates (FTLD-U), providing a new animal model that may help to better understand the pathophysiology and test new therapeutics. Beside genetic studies, several epidemiologic studies have investigated the role of environmental factors. A recent study suggests that smoking is a risk factor for developing ALS and it is hypothesized that this could occur through lipid peroxidation via formaldehyde exposure. From a neuroprotective perspective, trials with IGF-1, sodium valproate, coenzyme Q or glatiramer acetate have failed to demonstrate any beneficial effect. A study published in 2008 argued that lithium may have a neuroprotective effect in ALS mice and also in patients. However, two preclinical studies failed to replicate the neuroprotective effect of lithium in ALS mice. Therapeutic trials have been performed or are currently ongoing in Europe and North America. Their results have not yet been published.

[Retrospective study of ALS in French military personnel]

INTRODUCTION

An apparent increased risk for developing Amyotrophic Lateral Sclerosis (ALS), a multifactorial neurodegenerative disease, is considered to exist in the military population.

PATIENTS AND METHODS

ALS military and veteran patients were retrospectively recruited in April 2008 by searching medical data (Hippocrate) and repayment data (Erasme) of the French National Military Health Care Fund (Caisse nationale militaire de sécurité sociale, CNMSS) from de January 1991 to December 2007.

RESULTS

We report a series of 73 patients, 69 male and four female, average age of 52.5 years (range 27 to 72 years) with a peak of patients in the 50-59 year age class. The branch of military service was Army (n=26 patients), Air force (n=14), Navy (n=10) and State Police Force (n=22). The incidence among male active duty military personnel was stable from 2002 to 2007; it was less than the general population (1.7/100,000 per year in 2007), but higher in the 40-44 and 50-54 year age classes (1.90 and 5.07/100,000 per year in 2007 respectively). Duration of active duty was on average 31 years.

CONCLUSION

The retrospective nature of the data and the incomplete population with loss of retired military personnel without CNMSS affiliation are limitations of our study. Another means of collecting all cases of ALS among French military personnel and veterans would be to conduct a search in the 17 ALS centers in France with analysis by occupational activity for entire career.

Autophagy for the avoidance of neurodegeneration

Cellular defense mechanisms, including the unfolded protein response (UPR) and autophagy, attempt to resolve toxic protein aggregates, which are common denominators of neurodegenerative diseases. In this issue of Genes & Development, Hetz and colleagues (pp. 2294-2306) surprisingly show that inhibition of the UPR by knockout of XBP-1 causes a massive increase in autophagy, enhances clearance of superoxide dismutase 1 (SOD1) aggregates, and delays the development of amyotrophic lateral sclerosis. These findings suggest the existence of a homeostatic-if not hormetic-balance between distinct cellular defense mechanisms.