High hopes for cannabinoid agonists in the treatment of rheumatic diseases.

There are two well-characterised isoforms of cannabinoid receptor; CB1 and CB2 and of these CB2 is under active investigation as a potential target for treatment of the chronic pain associated with widespread and intractable joint diseases osteoarthritis and rheumatoid arthritis. The recent report by Fukuda et al (BMC Musculoskelet Disord15:275, 2014) in BMC Musculoskeletal Disorders investigates the efficacy of a selective CB2 agonist, JW133, in both in vitro and in vivo models of rheumatoid arthritis and provides encouraging data. The report shows that JW133 inhibits expression of the CCL2 cytokine, osteoclastogenesis and reduces histological indicators of joint degeneration. Each of these could potentially contribute to beneficial analgesic effects in a therapeutic context.