Unraveling the Pathological Mechanisms and Biomarkers of Amyotrophic Lateral Sclerosis: A Comprehensive Review

Amyotrophic lateral sclerosis (ALS) is an devastating neurodegenerative disorder with a very fast course and a very high fatality rate. The review discusses the intricate pathophysiology of ALS, such as the alterations caused by the genetic mutations of the C9orf72 and SOD1 genes, the misfolding and aggregation of proteins, oxidative stress, the excitotoxicity of glutamate, neuroinflammation, malfunctions in mitochondria, and axonal transport. Heterogeneity of the disease makes the development of biomarkers in ALS challenging; however, some promising candidates have been identified. Protein aggregation markers, including TDP-43 and SOD1, oxidative stress markers, such as 8-oxodG, neuroinflammatory markers, such as CRP and MCP-1, and neurological injury markers, such as NfL and pNfH, have potential in diagnosis, monitoring, and prediction. The miRNAs and particular metabolites can also provide clues to the molecular basis of ALS. The creation of biomarkers is challenged by the presence of a significant amount of disease heterogeneity and the lack of animal model reliability. The review highlights the importance of further research on biomarkers aimed at improving the diagnosis, treatment, and development of drugs for ALS. It supports the concept of a systematic biomarker development process, including genetic testing and molecular subgroup analysis, to enhance diagnostic accuracy and prognostic prediction capabilities. Exploring the interrelationship between the pathological process of ALS and the treatment based on multi-biomarker strategies is crucial for achieving effective management of this disease. As our understanding of ALS deepens, we expect to discover more new biomarkers in the future. This will significantly improve the diagnosis, treatment, and overall management of this devastating diseas.