Plasma endocannabinoid levels in multiple sclerosis

Background: Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS. Therapies that affect the endocannabinoid (EC) system may have immunomodulatory, symptomatic and neuroprotective effects. Aim: The aim of this study was to determine how levels of EC and related compounds are altered in MS. Methods: Plasma and whole blood were collected from 24 MS patients (10 relapsing-remitting (RR); 8 secondary-progressive (SP); 6 primary-progressive (PP); 19 females; 25-66 years) and 17 controls (10 females; 22-62 years). Plasma EC and related compounds were quantified by liquid chromatography-tandem mass spectrometry. Fatty acid amide hydrolase (FAAH), cannabinoid receptors CB1 and CB2 mRNA were measured by quantitative reverse transcriptase-polymerase chain reaction. Results: Anandamide (AEA) and palmitoylethanolamide (PEA) were higher in RRMS compared to controls (p = 0.001 and p = 0.027). AEA, PEA and oleoylethanolamide were also increased in SPMS plasma (p = 0.001, p = 0.004, and p = 0.005). PPMS patients had higher AEA plasma levels compared to controls (p = 0.009). FAAH mRNA was decreased in SPMS (p = 0.04) but not in RRMS or PPMS blood. CB1 (p = 0.012) and CB2 mRNA (p = 0.003) were increased in the PPMS. Conclusion: The EC system is altered in MS. It may be dynamically modulated depending on the subtype of the disease, but further studies with larger subgroups are needed to confirm this. (C) 2009 Elsevier B.V. All rights reserved.