HypeWatch: Cannabis Bone-Healing Study Oversold
— Forget the headlines you read. Here’s what you should know.
by Sydney Lupkin, Reporter, VICE News/MedPage Today July 23, 2015
A new study claims that a component in cannabis may help heal broken bones, but that doesn’t mean you should smoke a joint the next time you find yourself in a cast or on crutches.
Researchers at Tel Aviv University concluded that cannabidiol (CBD), a liquified non-psychotropic component of the cannabis plant, makes broken bones heal stronger. But their study was small, and it wasn’t in humans; it was in a couple dozen rats.
The results are preliminary at best, experts say.
“Insofar as these studies go, it’s not the worst I’ve seen, but the numbers are, I would say, on the low side,” said Jeffrey Nyman, PhD, of the Vanderbilt Center for Bone Biology.
The study was published in the Journal of Bone and Mineral Research and has generated such pun-tastic headlines as “No Bones About It: Cannabis May be Used To Treat Fractures” and “Joint Relief: Marijuana Helps Mend Broken Bones.”
But lead study author Yankel Gabet, DMD, PhD, of Tel Aviv University in Israel, said it’s not clear how CBD heals bones in rats, let alone whether it would work in humans.
“The main limitation is that this is the very first study on the matter and results have been obtained in animals only,” Gabet said.
Gabet and his team methodically broke the rats’ femurs and administered THC, CBD, or a ethanol/emulphor/saline solution that served as a control to see how well the rats’ bones healed over eight weeks using 3D micro-computed tomography and biomechanical machines. As part of a second experiment, they tried a mixture of THC and CBD, THC alone and CBD alone. The third experiment in the study involved measuring how THC and CBD affected the enzymes that prompt collagen crosslinking in healing bones, and the researchers reported that CBD enhanced expression of the enzyme lysyl hydroxylase 1, or PLOD 1.
Each group had between 5 and 12 rats, which Nyman said was not ideal. And after the eight weeks were up, Gabet and his team euthanized the rats, removed the once-broken femurs and studied them after first coating them in formalin, dehydrating and rehydrating them.
Margaret Gedde, MD, who has treated only medical marijuana patients since 2009 at her private practice in Colorado, said Gabet’s study is a good example of a basic animal study to pave the way for an eventual human study, but it’s not enough to draw conclusions for the future of fracture care.
“It would be a big leap to then conclude that CBD in a person, at a certain dose or used in a certain way, will help their bones heal,” she said. “Animals are not people. But, the study does lay new ground and points to the possibility that CBD in some form might be used to help bone healing in people.”
Robert Glatter, MD, who directs the emergency sports medicine program at Lenox Hill Hospital in New York City, expressed similar sentiments.
“Whether it translates to humans is unclear,” Glatter said. “It’s going to require much more work with multiple studies . That said, it’s encouraging.”
Glatter says he expects it will be another five or 10 years before doctors have CBD on hand to treat fracture patients in the ER — assuming CBD proves itself in human studies.
Nyman said he’d take the study with a grain of salt because of its small size and the fact that the researchers did something unusual: After euthanizing the animals and extracting the healed femurs, the researchers coated those femurs with formalin, a preservative. (They did not say how diluted it was.) Then, they dehydrated and rehydrated the femurs before examining them, measuring the callusing as well as meximal force, stiffness and work to failure, which are measurements of strength.
The formalin may have helped produce some of the bone-strengthening collagen crosslinking the researchers were attributing to the CBD, Nyman said. Even though this was done for all test subjects, he said the study was too small to say whether the formalin affected them equally and didn’t change the study outcome.
He said he was also confused about why the researchers coated the bones with barium sulfate, a dental varnish.
Furthermore, instead of making the rats’ bones heal faster, as many headlines are suggesting, the researchers found that rats given CBD actually healed slower than the others by 4 weeks after the fracture and then caught up.
“It’s very clear to me that this is not accelerated healing,” Nyman said.
Gabet and his team said that while they didn’t measure long term effects, previous studies have shown CBD to be safe.
“Implicating PLOD 1 in the mechanism of action of CBD may have far-reaching significances, beyond the improvement of fracture healing, in instances such as Ehlers-Danlos syndrome, bronchopulmonary dysplasia, bicuspid aortic wall-associated aneurisms, and cancer metastases,” wrote the authors, who included the so-called “grandfather of marijuana,” Raphael Mechoulam, PhD.
Decades ago, Mechoulam, now a medicinal chemist at the Hebrew University of Jerusalem, was the first to identify THC in cannabis.
Cannabis helps heal broken bones
Israeli researchers find non-psychotropic compound in marijuana is good therapy for fractures.
Add another page to the constantly growing body of evidence supporting the use of medical marijuana to treat pain and a variety of other conditions including diabetes, Parkinson’s disease, cancer and multiple sclerosis.
A study recently published in the Journal of Bone and Mineral Research by scientists from Tel Aviv University and the Hebrew University of Jerusalem explains that one of marijuana’s non-psychotropic component cannabinoids, cannabidiol (CBD), significantly enhanced the healing process of lab rats with mid-femoral (thighbone) fractures.
The research was led jointly by Dr. Yankel Gabet of the Bone Research Laboratory at TAU’s Sackler Faculty of Medicine and the late Prof. Itai Bab of Hebrew University’s Bone Laboratory. Participants included researchers from the Institute for Biomechanics in Zürich and from Lund University in Sweden.
The same team, in earlier research, discovered that cannabinoid receptors within our bodies stimulated bone formation and inhibited bone loss. This paves the way for the future use of cannabinoid drugs to combat osteoporosis and other bone-related diseases.
“We found that CBD alone makes bones stronger during healing, enhancing the maturation of the collagenous matrix, which provides the basis for new mineralization of bone tissue,” said Gabet. “After being treated with CBD, the healed bone will be harder to break in the future.”
Born with a cannabis system
According to Gabet, the human body is naturally equipped with a cannabinoid system that regulates both vital and non-vital systems including the skeleton. “We only respond to cannabis because we are built with intrinsic compounds and receptors that can also be activated by compounds in the cannabis plant,” he said.
The researchers injected one group of rats with CBD alone and another with a combination of CBD and tetrahydrocannabinol (THC), the psychoactive component of marijuana and hashish. After evaluating the administration of THC and CBD together in the rats, they found CBD alone provided the necessary therapeutic stimulus to get the femur healing faster.
“We found CBD alone to be sufficiently effective in enhancing fracture healing,” said Gabet. “Other studies have also shown CBD to be a safe agent, which leads us to believe we should continue this line of study in clinical trials to assess its usefulness in improving human fracture healing.”
The potential for using CBD as a preventative measure is also of great interest, given that worldwide, osteoporosis is estimated to cause more than 8.9 million fractures every year.
“The clinical potential of cannabinoid-related compounds is simply undeniable at this point,” said Gabet. “While there is still a lot of work to be done to develop appropriate therapies, it is clear that it is possible to detach a clinical therapy objective from the psychoactivity of cannabis. CBD, the principal agent in our study, is primarily anti-inflammatory and has no psychoactivity.”
The study cites the foundational research done on CBD by Prof. Raphael Mechoulam of the Hebrew University.