Heating elements in some vaping devices cause lung injury — animal study

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Early results of an experimental vaping study in rodents show significant lung injury from e-cigarette devices with nickel-chromium alloy heating elements, reports the University of California – Irvine. Previously it was thought that nicotine, tetrahydrocannabinol or vitamin E oil contributed to life-threatening vaping-association respiratory problems.

The findings were consistent, with or without the use of nicotine, vitamin E oil or tetrahydrocannabinol (THC), according to an article published in the Journal of the American Heart Association, UC Irvine reported on 28 September 2020.

The early results produced by researchers from the UC Irvine School of Medicine and the Huntington Medical Research Institutes or HMRI, were observed during a larger study designed to explore the effect of e-cigarette and other vaping product use on the cardiovascular system.

The nickel-chromium alloy problem

While conducting experiments, researchers observed e-cigarette (eC) or vaping product use-associated lung injury – called EVALI – immediately after switching from a vaping device with a stainless steel heating element, to one that used nickel-chromium alloy (NC).

“The results were so impactful, we felt it imperative to release the initial findings early so that electronic cigarette users could be cautioned sooner, especially considering e-cigarette users are at increased risk of COVID-19,” stated senior author Dr Robert A Kloner, chief science officer for HMRI.

The switch in devices occurred in September 2019, when the eC device the team was using went off market and a substitute device was offered as an alternative. The new device was physically compatible with the original exposure system, but the heating element changed from stainless steel (SS) to a nickel-chromium alloy (NC).

“Within an hour of beginning an experiment, we observed evidence of severe respiratory distress, including laboured breathing, wheezing and panting,” said Dr Michael Kleinman, professor of occupational and environmental medicine at UC Irvine School of Medicine and a member of the UC Irvine Center for Occupational and Environmental Health.

“After analysing lung tissue from subjects in the study, we found them to be severely compromised and observed other serious changes such as lung lesions, red blood cell congestion, obliteration of alveolar spaces, and pneumonitis in some cases.”

The current research aimed to study the impacts of breathing in e-cigarette vapours on heart function in a well-established pre-clinical experimental model.

Over the course of nearly a year, none of the subjects exposed to vapours from the stainless steel devices, both with and without additives, contracted respiratory distress and only one showed a less than 10% area of inflammation in the lungs.

Once the new eC device was introduced, affected subjects showed severe respiratory distress. The lung injury occurred without nicotine, THC or Vitamin E additives; and may also have been related to higher wattage of power settings on the E-cigarette devices.

Looking ahead

These preliminary studies will be followed up with additional future studies to systematically try to determine the cause of the lung problem.

“While further research is needed, these results indicate that specific devices and power settings may play a key role in the development of EVALI as much as the additives do,” said Kloner. “The harms associated with e-cigarettes and vaping simply cannot be overstated.”

Vaping has been proven to cause increased blood pressure, endothelial dysfunction, and the risk of myocardial infarction and stroke. Heating elements in commercially available eC are usually made of stainless steel, nickel-chromium or nichrome, Kanthal nickel, or titanium.

The condition, which was dubbed EVALI – “E-cigarette or vaping product use-associated lung injury” – was recognised in the United States in June 2019 and peaked in September 2019. In March 2020, there were 2,800 US cases of EVALI and 68 deaths reported.

Patients were typically found to be young males and users of e-cigarettes or vaping products whose CT scans revealed lung inflammation and injury. Of note, EVALI can mimic many of the features of COVID-19 pneumonia.

 

E‐cigarette or Vaping Product Use–Associated Lung Injury Produced in an Animal Model From Electronic Cigarette Vapor Exposure Without Tetrahydrocannabinol or Vitamin E Oil

Journal of the American Heart Association. Published on 8 September 2020.

Authors

Michael T Kleinman, Rebecca Johnson Arechavala, David Herman, Jianru Shi, Irene Hasen, Amanda Ting, Wangde Dai, Juan Carreno, Jesus Chavez, Lifu Zhao and Robert A Kloner

Author affiliations: The authors are affiliated with the Cardiovascular Research Institute at Huntington Medical Research Institutes, or the Department of Medicine at the University of California – Irvine.

Abstract

E‐cigarette or vaping product use–associated lung injury or EVALI was recognised in the United States in the summer of 2019 and is typified by acute respiratory distress, shortness of breath, chest pain, cough and fever, associated with vaping.

It can mimic many of the manifestations of coronavirus disease 2019 (COVID‐19). Some investigators have suggested that e‐cigarette or vaping product use–associated lung injury was due to tetrahydrocannabinol or vitamin E acetate oil mixed with the electronic cigarette liquid.

In experimental rodent studies initially designed to study the effect of electronic cigarette use on the cardiovascular system, we observed an e‐cigarette or vaping product use-associated lung injury‐like condition that occurred acutely after use of a nichrome heating element at high power, without the use of tetrahydrocannabinol, vitamin E or nicotine.

Lung lesions included thickening of the alveolar wall with foci of inflammation, red blood cell congestion, obliteration of alveolar spaces, and pneumonitis in some cases; bronchi showed accumulation of fibrin, inflammatory cells, and mucus plugs.

Electronic cigarette users should be cautioned about the potential danger of operating electronic cigarette units at high settings; the possibility that certain heating elements may be deleterious; and that e‐cigarette or vaping product use-associated lung injury may not be dependent upon tetrahydrocannabinol, vitamin E or nicotine.

 

Heating in vaping device as cause for lung injury, study shows

 

E‐cigarette or Vaping Product Use–Associated Lung Injury Produced in an Animal Model From Electronic Cigarette Vapor Exposure Without Tetrahydrocannabinol or Vitamin E Oil

 


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