Effect of JUUL e-Liquid Extracts on Osteoblast Survival and Function

Objectives: Electronic vaping devices deliver nicotine in a manner similar to conventional cigarettes. While cigarette smoking has been proven to increase periodontal disease and oropharyngeal cancer risks, extensive studies on the health effects of vaping have yet to be published. JUUL, a brand of electronic cigarettes, is popular among smokers due to its sleek, inconspicuous design as well as reports of its decreased carcinogenic effects. A JUUL consists of a device containing a removable cartridge, or “JUULpod,” that holds an e-liquid of various flavors and nicotine concentrations. Although electronic cigarette use is viewed as a healthy alternative to conventional cigarette smoking, the long-term health effects of vaping are not known at this time. Therefore, this study is to determine the effects of JUUL e-liquid concentrates on the survival and function of osteoblasts.
Methods: Osteoblasts were treated for 1, 6, and 24 hours with various percentages (2%, 4%, 6%, 8%, 10%) of JUULpod e-liquid containing 59 mg/ml nicotine in a mix of propylene glycol, glycerine, benzoic acid, and flavoring agents. The flavors tested included mint, Virginia tobacco, mango, and crème. Cell survival was assessed fluorometrically using Calcein-AM. Alkaline phosphatase activity was measured by enzymatic assay. Osteoblast transcript expression was evaluated using polymerase chain reaction and gel electrophoresis.
Results:
Concentrations of JUULpod e-liquid up to 25% extract did not significantly reduce cell survival for all flavors. Concentrations of JUULpod e-liquid up to 25% extract drastically reduced alkaline phosphatase activity in osteoblasts. No detectable changes in osteoblast transcript were noted.
Conclusions:
Based on these results, JUULpod e-liquid did not reduce the survival of osteoblasts. However, JUULpod e-liquid does significantly reduce alkaline phosphatase activity of osteoblasts. This study supports the likelihood that electronic cigarettes would be less harmful to osteoblasts than conventional cigarettes.