Identification of Unique Cell Types in ALS Patients

Understanding Amyotrophic Lateral Sclerosis

Researchers have discovered distinctive cell types in the spinal cords of amyotrophic lateral sclerosis (ALS) patients, potentially paving the way for early diagnosis. ALS, also known as Lou Gehrig’s disease, is a neurodegenerative condition that primarily affects neurons within the central nervous system. The disease is marked by a gradual loss of motor neurons in both the brain and spinal cord, leading to paralysis, muscle degeneration, and, ultimately, death.

ALS typically presents with a “focal onset,” where motor neuron degeneration begins in one region of the spinal cord and gradually extends to nearby areas. This pattern often corresponds with the initial paralysis experienced in the arms or legs, which can then spread throughout the body. In advanced stages, the disease may affect neurons responsible for lung function, disrupting the essential signals needed for breathing.

Challenges in Early Diagnosis

Current diagnostic methods are limited due to the absence of recognized biomarkers for early-stage ALS. However, researchers at the University of Illinois in Chicago have identified specific cellular changes in the spinal cord that occur during the progression of the disease. These changes may manifest before any noticeable symptoms arise, serving as potential early indicators of ALS onset.

The research team utilized a novel bioinformatics tool to scrutinize genomic data from spinal motor neurons obtained from ALS patients who had passed away. These samples originated from less affected regions of the spinal cord, representing the early stages of the disease. Their findings, published in the journal *Neurobiology of Disease*, provide insights into the specific cell types present in ALS patients as compared to healthy individuals.

Key Findings and Implications

“When we examined the data, it was clear that the mixture of cells from the ALS patients was very different from patients with no neurodegenerative disease,” stated Dr. Fei Song, associate professor of neurology and rehabilitation at the UIC College of Medicine and senior author of the study. The analysis revealed that ALS patients exhibited different types of spinal motor neurons, which were associated with immune cells known as microglia and macrophages.

Evidence suggests that neuroinflammation, a factor in the pathogenesis of ALS, may be influenced by microglia and other immune cells. Although the precise mechanisms by which inflammation contributes to neuron death remain unclear, these findings support the theory that motor neurons and immune cells interact throughout the progression of the disease.

“Now that we have identified new subtypes of motor neurons and microglia present in ALS patients, we can begin to further study their roles in contributing to disease progression,” Dr. Song remarked. The discovery of these disease-specific motor neurons and glial cells may lead to novel biomarkers or therapeutic targets aimed at slowing the progression of ALS.

References

Dachet, F., Liu, J., Ravits, J. & Song, F. Predicting disease specific spinal motor neurons and glia in sporadic ALS. *Neurobiology of Disease* 130, 104523 (2019).
Parmet, S. Researchers describe new ALS biomarkers, potential new drug targets. UIC today (2019).
Image by Arek Socha from Pixabay.