Individual donor cultures exposed to cannabis smoke experienced a decrease in epithelial barrier function.
Each cannabis sample used in the experiments was about 0.7 grams of dried flower, with the bud purchased from Ontario Cannabis Store with a Health Canada-approved research licence, notes the paper. Using one puff of smoke separated by three puffs of fresh room air served to mimic the behaviour of human smoking patterns.
“Our results suggest that individual donor cultures exposed to cannabis smoke in IVES experienced a decrease in epithelial barrier function as compared to air-exposed controls,” study authors write. “Cell cytotoxicity was minimally impacted by our model,” the results further suggest.
When human airway epithelial cells were exposed to cannabis smoke using IVES, there were changes in cell morphology and disruption of barrier function without significant cytotoxicity. Other parameters also validated “IVES smoke exposure impacts in human airway epithelial cells at a molecular level.”
Dysfunction involving the airway epithelium “has been strongly implicated in the pathogenesis of many airway diseases, including asthma, chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis,” the study states. But so, too, is there a risk of the same respiratory diseases as a result of environmental insults capable of damaging the airway epithelium.
Both tobacco and cannabis smoking represent two examples of such direct environmental insults, study authors note. Environmental exposures of both are associated with a higher prevalence of coughing, wheezing, chest tightness and risk for developing COPD, although the two diverge on lung cancer.
“Tobacco smokers [are] more likely to develop lung cancer relative to cannabis smokers,” the researchers point out, perhaps as a result of the anti-inflammatory properties of phytocannabinoids unique to weed.
Researchers note that the development and validation of a low-cost in vitro environmental exposure system “will broaden the ability of researchers to perform essential research related to cannabis smoke exposure and lung health.”
Additive manufacturing technologies, “have accelerated prototyping steps while reducing costs, effectively enabling researchers with limited design training to optimize novel designs independent of historical manufacturing constraints,” they write.
The researchers do acknowledge, however, that the conditions used in the study “represent a single possible combination that does not provide concentration-response outcomes that may be impacted by length of time for combustion, frequency and volumes of inhalation/exhalation, and mass of cannabis combusted.”
Even so, overall, more research around the effect of cannabis smoke is necessary. “The uncertainty surrounding the health effects of cannabis smoke and discrepancies with the known negative impacts of tobacco smoke warrants further investigation to inform government policies, recreational practices and cultivation strategies in an era of broadening acceptance for legal and open markets,” researchers say.
Pointing out that IVES is an accessible, open-source, exposure system that can be used to model varying types of cannabis smoke exposures, the researchers recommend “the growing legalization of cannabis on a global scale must be paired with research related to potential health impacts of lung exposures.”
Future studies can expand applications to explore different concentrations, durations of smoke, period of smoke, co-exposure with pathogens or introduction of vaping technologies, they add.
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