Metabolomics of neurodegenerative diseases.

Neurodegenerative diseases are progressive, devastating, and terminal, carrying both personal and societal burden. Currently, their diagnosis depends on their clinical presentation. No quantitative biomarkers exist to enable early verdict and commencement of therapy. The lack of diagnostic biomarkers stems from the unavailability of brain tissue, the complexity and heterogeneity of the brain and neurodegenerative pathology, and the fact that peripheral tissues such as blood, urine, and even cerebrospinal fluid might not reflect early stages of brain pathology. Moreover, accumulated evidence indicates the majority of these diseases are not genetically inherited; rather, the genes bring about the risk to develop them, but the trigger is not known. As metabolites are at the intersection between the genetic background of a cell or a tissue and the environmental effects on the same, metabolomics has emerged as a field with great promise to deliver new, biologically, and clinically relevant biomarkers for neurodegenerative disorders. Here, we review the basic principles of metabolomics and focus on studies performed in most common neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases, Multiple sclerosis, and Amyotrophic lateral sclerosis.