Identification of Putative Biomarkers in the Serum of Marijuana Users by Surface‐Enhanced Laser Desorption/Ionization Time of Flight Mass Spectrometry (SELDI‐TOF‐MS)

Marijuana is the most commonly used illicit drug in the United States. Delta‐9‐tetrahydrocannabinol (THC), the active ingredient in marijuana (MJ), rapidly passes from the lungs and goes to the brain via the bloodstream. In addition to its euphoric effects, long‐term abuse of MJ is associated with learning and memory dysfunctions, perceptual abnormalities, and neuroimaging abnormalities. The use of MJ is also associated with immune dysfunctions. Although no medications are currently available to treat MJ abuse, identification of biomarkers of MJ abuse might help in the creation of more specific diagnostic criteria for MJ use disorders. This, in turn, might help in the development of more specific therapeutic approaches to these disorders. Proteomics, the analysis and characterization of overall protein modifications, is helping to revolutionize our understanding of protein function. It is also aiding in the discovery of biomarkers and/or therapeutic targets of human diseases. The recent development of the protein chip platform based on SELDI‐TOF allows for the high‐throughput analysis of complex protein mixtures from serum, body fluids, and other cell extracts. We have, thus used this approach in a study of 25 controls and 19 MJ abusers in order to determine if specific biomarkers might differentiate MJ users from control subjects. There were indeed some proteins that were more highly expressed in the MJ group. The possibility that these proteins might serve as biomarkers of MJ abuse will have to await future experiments.