l-Carnitine Exposure and Mitochondrial Function in Human Neuronal Cells

• Published in: Neurochemical research 2013-11, Vol.38 (11), p.2336-2341
• Main Authors: Geier, David A., Geier, Mark R.
• Format: Article
• Language: English
• Subjects: Biochemistry; Biomedical and Life Sciences; Biomedicine; Carnitine - pharmacology; Cell Biology; Cognition - drug effects; Humans; Mitochondria - drug effects; Mitochondria - physiology; Neurochemistry; Neurology; Neurosciences; Original Paper; Tumor Cells, Cultured
• ISSN: 0364-3190; 1573-6903
• DOI: 10.1007/s11064-013-1144-7

l -Carnitine is a naturally occurring substance required in mammalian energy metabolism that functions by facilitating long-chain fatty acid entry into cellular mitochondria, thereby delivering substrate for oxidation and subsequent energy production. It has been purposed that l -carnitine may improve and preserve cognitive performance, and may lead to better cognitive aging through the life span, and several controlled human clinical trials with l -carnitine support the hypothesis that this substance has the ability to improve cognitive function. We further hypothesized that, since l -carnitine is an important co-factor of mammalian mitochondrial energy metabolism, acute administration of l -carnitine to human tissue culture cells should result in detectable increases in mitochondrial function. Cultures of SH-SY-5Y human neuroblastoma and 1321N1 human astrocytoma cells grown in 96-well cell culture plates were acutely administered l -carnitine hydrochloride, and then, mitochondrial function was assayed using the colorimetric 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt cell assay kit in a VERSA max tunable microplate reader. Significant increases in mitochondrial function were observed when human neuroblastoma or human astrocytoma cells were exposed to 100 nM (20 μg l -carnitine hydrochloride/L) to 100 μM (20 mg l -carnitine hydrochloride/L) concentrations of l -carnitine hydrochloride in comparison to unexposed cells, whereas no significant positive effects were observed at lower or higher concentrations of l -carnitine hydrochloride. The results of the present study provide insights for how l -carnitine therapy may significantly improve human neuronal function, but we recommend that future studies further explore different derivatives of l -carnitine compounds in different in vitro cell-based systems using different markers of mitochondrial function.