Muscle biopsy test for biomarker could lead to earlier diagnosis of amyotrophic lateral sclerosis

amyotrophic lateral sclerosis

A disorder of the neurological system that progresses is called amyotrophic lateral sclerosis (ALS). Motor neurons, which are nerve cells in the brain and spinal cord, are impacted. Muscle movement is regulated by motor neurons, which become damaged and eventually die as a result of ALS. The body's muscles can no longer communicate with the motor neurons, which has an impact on voluntary muscle movements. ALS treatment has advanced recently, however, the existing therapies can only slow the disease's progression. Because of this, it's critical to get an ALS diagnosis as soon as possible.

There is presently no one test that can definitively detect ALS, making it challenging to make a diagnosis. Doctors examine for neurological symptoms such as upper and lower motor neuron complaints and muscle weakness. In order to rule out further disorders like cervical spondylosis, they will also do diagnostic testing. People would be able to receive a diagnosis earlier and begin treatment more quickly if a diagnostic test that could confirm ALS was available.

Researchers describe preliminary studies that might pave the way for a future test to identify ALS in a report that was published on May 23 in JAMA Neurology.

According to researcher Hirofumi Maruyama, a professor at the Graduate School of Biomedical and Health Sciences at Hiroshima University in Hiroshima, Japan, "ALS is difficult to diagnose in its early stages because there is not a known biomarker." "Transactive response DNA-binding protein 43 (TDP-43) builds up in the peripheral neurons of muscle, and muscle can be biopsied. A protein called TDP-43, which is essential for motor neurons, may serve as a diagnostic for the early detection of ALS."

Previous studies in mice have shown that TDP-43 plays a critical role in the axon, the portion of the neuron that transmits impulses to other neurons. The lower motor neuron issues that can be an ALS sign are caused by axonal degradation, therefore understanding this is crucial. TDP-43 buildup in muscle nerve bundles was thought to be a potential early indicator of ALS, according to researchers.

Researchers first looked at the muscle tissue of 10 people who had ALS at the time of their deaths and 12 people who did not in order to test this notion. In contrast to the 12 non-ALS controls, all 10 individuals with ALS had TDP-43 accumulations in their intramuscular nerve bundles.

Next, researchers focused on 114 patients who had muscle biopsies and did not have a family history of ALS or another illness involving the muscles or nervous system. 43 of them lacked signs of intramuscular nerve bundles, while 71 of them did. Axonal TDP-43 accumulations in the nerve bundles of 33 of the 71 individuals were confirmed. All 33 of these patients with axonal TDP-43 accumulations were subsequently identified as having ALS. Three of the 43 patients without nerve bundles ultimately had ALS diagnoses.

As a result, axonal TDP-43 accumulations may represent a unique diagnostic biomarker for ALS, according to Maruyama, who summarized the findings of this dual case-control and cohort study. "Patients can start quick treatment when they receive an early diagnosis. Our goal is to stop the spread of ALS, and we'll keep working to find new treatments."


Materials provided by Hiroshima University.

Takashi Kurashige, Hiroyuki Morino, Tomomi Murao, Yuishin Izumi, Tomohito Sugiura, Kazuya Kuraoka, Hideshi Kawakami, Tsuyoshi Torii, Hirofumi Maruyama. TDP-43 Accumulation Within Intramuscular Nerve Bundles of Patients With Amyotrophic Lateral Sclerosis. JAMA Neurology, 2022; DOI: 10.1001/jamaneurol.2022.1113


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