Comparison of brain nicotine uptake from electronic cigarettes and combustible cigarettes.

Introduction:
This article compares brain nicotine uptake from electronic cigarettes (E-cigs) and combustible cigarettes (C-cigs) using a within-subjects design. The study directly assessed brain accumulation rate and magnitude of nicotine in dual users of E-cigs and C-cigs. The key points and main message of the text are summarized below.

Key Points:

* The study included 16 adult dual users of E-cigs and C-cigs.
* Participants went through two 15-min head scanning sessions during which they inhaled a single puff of E-cig vapor or C-cig smoke containing 11C-nicotine in a randomized order.
* a full-body scan was conducted at each session to measure total absorbed dose of 11C-nicotine.
* Mean maximum concentration (C max) and area under curve of BNa were 22.1% and 22.7% lower, respectively, following E-cig compared with C-cig inhalation.
* Whole-body imaging indicated greater nicotine retention in the respiratory tract from vapor versus smoke inhalation (p< 0.0001).
* Following vapor inhalation, nicotine retention in the respiratory tract was correlated with C maxvalues of BNa (rs=−0.59, p< 0.02).
* The results suggest that E-cigs with alkaline ph e-liquid can deliver nicotine rapidly to the brain, albeit less efficiently than C-cigs partly due to greater airway retention of nicotine.

Main Message:
The main message of the text is that E-cigs can deliver nicotine rapidly to the brain, but less efficiently than C-cigs. The study highlights the importance of understanding the pharmacokinetics of nicotine delivery from E-cigs, particularly in the context of their potential role in tobacco harm reduction. The findings suggest that E-cigs may lead to the development and maintenance of nicotine dependence, but they are also promising substitutes for combustible cigarettes and thereby may promote smoking cessation and harm reduction. however, the study emphasizes the need for further research to address the limitations of the study and to better understand the potential health consequences of nicotine deposition in the respiratory tract. Overall, the study provides valuable insights into the use of E-cigs as a harm reduction tool and highlights the need for continued research and regulation in this area.

Zuo Y, Mukhin aG, Berg h, et al. Comparison of brain nicotine uptake from electronic cigarettes and combustible cigarettes. Neuropsychopharmacology : official publication of the american College of Neuropsychopharmacology. 2022;47(11):1939-1944. doi:10.1038/s41386-022-01410-5