Dimethyl fumarate: A review of preclinical efficacy in models of neurodegenerative diseases

Dimethyl fumarate (DMF) is an antioxidative and anti-inflammatory drug approved for treatment of multiple sclerosis and psoriasis; however, beneficial effects of DMF have also been found in other inflammatory diseases and cancers. DMF is a prodrug that is immediately hydrolysed to monomethyl fumarate (MMF) in vivo. Both fumarates activate the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway, and Nrf2 is a key transcription factor of the antioxidant response. The immunosuppressive and anti-inflammatory actions of DMF occur through several mechanisms: via inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway and by downregulation of aerobic glycolysis and pyroptosis in activated myeloid and lymphoid cells. MMF is also an agonist of hydroxycarboxylic acid receptor 2 (HCAR2). Differences in the strength of effects and mechanisms of action of both fumarates are discussed. The aim of this review was to analyse and compare the neuroprotective, antioxidative and anti-inflammatory effects of DMF and its active metabolite, MMF, in cellular (in vitro) and animal models of neurodegenerative diseases (NDs), other than multiple sclerosis. There are more than twenty studies that currently represent this field. Most of the studies are concerned with cellular or animal models of Alzheimer's disease (AD) and Parkinson's disease (PD), one utilized a mouse model of Huntington's disease (HD) and one clinical trial was carried out with amyotrophic lateral sclerosis (ALS) patients. The discrepancies in the results of the various studies are discussed, and issues requiring further research have been identified.