Acetyl L-Carnitine Nanoparticles Modulate Neuronal and Inflammatory Responses in In Vitro Cell Model

Acetyl L-carnitine is an ester of the trimethylated amino acid L-carnitine with well-documented neuroprotective properties. Despite its ability to cross the blood-brain barrier, acetyl L-carnitine requires high and repeated doses to achieve and maintain therapeutic concentrations in the central nervous system. To overcome these limitations, nanotechnology-based delivery systems have emerged as a promising strategy to improve drug bioavailability, targeting, and therapeutic efficacy. In this study, we evaluated the efficacy of nanoparticle-based formulations of acetyl L-carnitine in comparison with its conventional bulk form using in vitro cultures of SH-SY5Y neuroblastoma cell line. The ALC nanoparticles were produced through an organic solvent-free mechanical ball milling process employing a planetary ball mill. The dimension and stability of the nanoparticles were analyzed by Dynamic Light Scattering and Thermogravimetric Analysis. The biological effects were evaluated using quantitative Real Time-Polymerase Chain Reaction, Enzyme-linked Immunosorbent Assay and immunofluorescence experiments. ALC nanoparticles, at low concentration of nanoparticles compared to the non-nanoparticle form, were able to decrease the alarmin S100B release, pro-inflammatory interleukin mRNA and protein expression as well as p65 activation, confirming their involvement in NF-κB pathway. Moreover, it was able to stimulate the nerve growth factor release and to increase intracellular Ca⁺⁺ levels, showing neuroprotective effects in addition to anti-inflammatory ones. Our findings allow us to highlight the therapeutic potential of ALC nanoparticles for neurological disorders, with the prospect of enhancing efficacy while reducing dosage and administration frequency.