CANNABINATION

CB2 Receptor Mutations Linked to Bone Health

Genetic variations, polymorphisms, or mutations on the gene for the Cannabinoid Type 2 (CB2) Receptor have been linked to osteoporosis, low Bone Mineral Density (BMD), and hand bone strength in case controlled Studies (Yamada 2007, Karsak 2005, and Karsak 2009).

Most cannabinoid research on bone has been conducted in rats and mice. These recent case controlled studies in humans have established a significant association between CB2 gene polymorphisms/mutations to certain bone phenotypes; Mutant CB2 receptors lead to bad bones.

The first study (Karsak 2005) looked at CB1 and CB2 receptor DNA in a sample of French post-menopausal patients and female controls. The authors report that certain changes in CB2 receptor, but not the CB1 receptor, were strongly associated with osteoporosis. The authors claim this is the first study to find a link between the CB2 receptor and a disease in human patients. A study published out of Japan replicated these findings in 2007, in a group of pre and post menopausal women.

Furthermore, it has been speculated that CB2 receptor activation can inhibit atherosclerotic plaques. Atherosclerosis is a late onset disorder, that is inversely correlated to bone mineral density.  If your bone density or strength starts decreasing, atherosclerosis progresses. So, CB2 receptor variations could explain the association between the two disorders. THC has already been shown to reduce atherosclerosis in mice by activating the CB2 receptor.

The third study on CB2 genes in humans, examined the role of CB2 DNA or genes on hand bone strength. The author took radio-graphic images and DNA samples from a Chevashian population, an ethnically homogeneous population of people of Bulgaric ancestry that live along the Volga river.

The authors found several recurring, small mutations or SNPs (Small Nucleotide Polymorphisms) were significantly associated certain bone phenotypes. Basically, a less functional form of the CB2  receptor leads to weak hand bone strength.

These studies have showed that the effects of CB2 receptor gene variations have been observed in three different genetic/ethnic backgrounds. Thus supporting a link between the CB2 receptors in humans and bone health. Drugs that activate this receptor are of medical value and importance.

While it appears that cannabinod receptor activation may be positively associated with bone health, no studies have been approved for observing the long term effects of cannabis use/ receptor activation on bone health. An anecdotal answer could be easily derived by comparing different measurements of bone health in long term cannabis users vs. non-users.