Juul and earlier generation e-cigs clobber blood vessels as much as a Marlboro Red

My colleagues Poonam Rao, Jiangtao Liu, and Matt Springer just published “JUUL and Combusted Cigarettes Comparably Impair Endothelial Function” in Tobacco Regulatory Science. They compared to Juul, a third generation tank system e-cigarette (the kind FDA is giving a pass in its enforcement against some e-cig flavors), and a Marlboro Red cigarette against clean air affect arteries’ ability to dilate (get larger) in the face of increased demands for blood flow.   Impairment of this so-called flow mediated dilation (FMD) makes impaired functioning of the cardiovascular system and predicts future heart attack risk.

The graph below (taken from Figure 3 of the paper) shows the similarities in how these three tobacco products reduce FMD:

E-cigarette apologists will no doubt criticize this paper because it was a study of rats not people, but the reality is that this animal experimental model is well-established.

Another important fact:  The study used Juul Virginia Tobacco flavor; the new FDA enforcement policy also exempts tobacco flavor.

Here is the paper’s abstract:

Objectives: JUUL and earlier generation electronic cigarettes (e-cigs) are promoted as being less hazardous than cigarettes. JUUL Labs, in particular, claims that switching from smoking to vaping has beneficial impacts; however, the health effects of such products are not well understood. We investigated whether exposure to JUUL and previous generation e-cig aerosol impairs endothelial function comparably to cigarette smoke. Methods: We exposed rats to aerosol from Virginia Tobacco flavor JUUL, an e-cig tank system using unflavored free-base nicotine e-liquid, Marlboro Red combustible tobacco cigarettes, or clean air for 10 cycles of 2 second inhalation over 5 minutes. We measured endothelial function pre- and post-exposure. Blood was collected 20 minutes post-exposure for serum nicotine analysis. Results: Aerosol/smoke from JUUL, previous generation e-cigs, and cigarettes all impaired endothelial function. The extent of impairment ranged from 34% to 58%, although the differences between groups were not statistically significant. Nicotine was highest in serum from the JUUL group; for the other e-cig and cigarette groups, nicotine levels were lower and comparable to each other. Conclusions: Aerosol from

JUUL and previous generation e-cigs impairs endothelial function in rats, comparable to impairment by cigarette smoke.

The full citation is:  Rao P, Liu J, Springer M.  JUUL and Combusted Cigarettes Comparably Impair Endothelial Function. Tob Regul Sci.™ 2020;6(1):30-37.  DOI: https://doi.org/10.18001/TRS.6.1.4.  It is available here.

Here is the UCSF press release on the paper:

FOR IMMEDIATE RELEASE

Jennifer O’Brien, Asst. Vice Chancellor/Public Affairs

Source: Scott Maier (415) 502-6397 (NEWS)

[email protected] | @samaier

JUUL Delivers Substantially More Nicotine than Previous Generation E-Cigs and Cigarettes

JUUL Also Impairs Blood Vessel Function Similar to Cigarette Smoke, UCSF Researchers Find

JUUL delivers substantially more nicotine to the blood per puff than cigarettes or previous-generation e-cigarettes (e-cigs) and impairs blood vessel function comparable to cigarette smoke, according to a new study by researchers at UC San Francisco.

The study, which appeared online January 4, 2020, in Tobacco Regulatory Science, found that nicotine concentrations were five to eight times higher in rodents that were exposed to JUUL versus other tobacco products. The work also supports an earlier finding by the same researchers of harm to blood vessels from brief exposures to both direct and secondhand smoke from cigarettes, little cigars and combustible marijuana, and to aerosol from IQOS “heat-not-burn” tobacco products.

JUUL and earlier generation e-cigs are promoted as being less hazardous than cigarettes. Since 2016, there has been a dramatic increase in youth e-cig use, with JUUL devices particularly effective at recruiting teenagers to begin nicotine usage. A recent study found 27.5 percent of high school students and 10.5 percent of eighth graders currently use e-cigs, with more than half of both groups using JUUL as their preferred choice.

A caveat of this study is that it measured the impact of equal numbers of puffs of all products, whereas adult former cigarette smokers may stop their vaping session when they reach the level of nicotine they normally ingest, said senior author Matthew Springer, PhD, professor of cardiology at UCSF and member of the UCSF Center for Tobacco Research and Education.

“However, adolescent non-smokers who are not familiar with the effects of nicotine may be more likely to chase higher levels of the drug’s effects,” Springer said. “The ease of over-consuming nicotine with JUUL makes this likely, especially in light of reports of teenagers binging on JUUL to the point of rapid addiction and behavioral consequences.”

As with earlier-generation e-cigs, the liquid in JUUL pods is composed of vegetable glycerin and propylene glycol, along with flavors and nicotine. But while the freebase nicotine used in earlier generations limits the amount comfortably inhaled, JUUL has introduced acidified nicotine salts, which are easier to inhale and deliver nicotine at substantially higher concentrations.

In the Tobacco Regulatory Science study, eight rats were exposed to 10 cycles of two-second inhalation over a five-minute period, with one of four different substances: JUUL, an e-cigarette with freebase nicotine e-liquid, cigarettes or clean air. The researchers collected blood samples 20 minutes after exposure and measured blood vessel impact through a process known as flow mediated dilation. This approach, which is a validated measurement of human cardiovascular health, has been shown in rodents to yield pharmacological and biophysical effects similar to humans, Springer said.

The research found that blood nicotine concentrations in the JUUL group (136.4 ng/ml) was eight times higher than e-cigs group (17.1 ng/ml) and 5.2 times higher than cigarettes (26.1 ng/ml).

However, while Springer and his colleagues found that aerosol or smoke from JUUL caused greater blood vessel impairment than either of the other nicotine sources, the differences in the extent of impairment between the sources themselves was deemed statistically insignificant.

“The comparison of cardiovascular health effects of JUUL use with those of previous generation e-cigs and of combusted cigarettes is an important issue for policymakers, including the FDA and comparable bodies outside the United States,” Springer said. “Our findings show that the adverse effect of cigarettes on vascular endothelial function, which has been a known consequence of cigarette smoking since the 1990s, is not prevented by using JUUL.”

Other study contributors were lead author Poonam Rao and Jiangtao Liu, of UCSF. Financial support was provided by National Institutes of Health National Heart, Lung, and Blood Institute grants R01HL120062 and U54HL147127, U.S. Food and Drug Administration Center for Tobacco Products, and a donation from the Elfenworks Foundation in memory of Deb O’Keefe. The authors report no conflicts of interest.

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