Mechanistic perspectives on differential mitochondrial-based neuroprotective effects of several carnitine forms in Alzheimer's disease in vitro model

Mitochondrial deregulation has emerged as one of the earliest pathological events in Alzheimer's disease (AD), the most common age-related neurodegenerative disorder. Improvement of mitochondrial function in AD has been considered a relevant therapeutic approach. l-carnitine (LC), an amino acid derivative involved in the transport of long-chain fatty acids into mitochondria, was previously demonstrated to improve mitochondrial function, having beneficial effects in neurological disorders; moreover, acetyl-l-carnitine (ALC) is currently under phase 4 clinical trial for AD (ClinicalTrials.gov NCT01320527). Thus, in the present study, we investigated the impact of different forms of carnitines, namely LC, ALC and propionyl-l-carnitine (PLC) on mitochondrial toxicity induced by amyloid-beta peptide 1-42 oligomers (A beta O; 1 mu M) in mature rat hippocampal neurons. Our results indicate that 5 mM LC, ALC and PLC totally rescued the mitochondrial membrane potential and alleviated both the decrease in oxygen consumption rates and the increase in mitochondrial fragmentation induced by A beta O. These could contribute to the prevention of neuronal death by apoptosis. Moreover, only ALC ameliorated A beta O-evoked changes in mitochondrial movement by reducing the number of stationary mitochondria and promoting reversal mitochondrial movement. Data suggest that carnitines (LC, ALC and PLC) may act differentially to counteract changes in mitochondrial function and movement in neurons subjected to A beta O, thus counteracting AD-related pathological phenotypes.

Automated summary

The study investigated the impact of different forms of carnitines on mitochondrial toxicity induced by amyloid-beta peptide 1-42 oligomers in rat hippocampal neurons. LC, ALC, and PLC showed potential in rescuing mitochondrial membrane potential and alleviating changes in oxygen consumption rates and mitochondrial fragmentation induced by A beta O. ALC was specifically effective in improving mitochondrial movement, reducing the number of stationary mitochondria and promoting reversal mitochondrial movement.