The study claims that nicotine causes a loss of integrity in the lung endothelial cells – the cells that make up the lining of the lung – and can contribute to lung injury and acute (short term) inflammation.
Lets start by showing quotes from the actual study and my own interpretations of the findings:
Line 402: “The signaling effects on nicotine-free e-Cig vapors on the lung endothelial barrier remain to be investigated.”
This quote is stating the exact opposite of what many articles like this one from Science Daily titled “E-cigarette vapor, even when nicotine-free, found to damage lung cells” are reporting. It is clear when you read the actual study that it “remains to be investigated” Reference line 402 of the study.
Line 217 -219: “To investigate the contribution of nicotine in CS (Cigarette Smoke) extract to the loss of lung endothelial barrier function, we compared the effect of soluble extract from nicotine-containing and nicotine-free cigarettes.”
Researchers are stating that to find out if nicotine creates a loss of lung cell barrier function, they used a soluble cigarette smoke extract (not e-Cig vapor) to reach their conclusions.
Line 201: “In a separate quantitation experiment, nicotine and quinoline were diluted with dichloromethane to produce four standard solutions: a 100 mg/mL nicotine, 1 mg/mL quinoline solution; a 10 mg/mL nicotine, 1 mg/mL quinoline solution; a 1 mg/mL nicotine, 1 mg/mL quinoline solution; and a 0.1 mg/mL nicotine, 1 mg/mL quinoline solution. Primary rat lung endothelial cells (RLECs) exposed to nicotine-containing CS (cigarette smoke) extract, exhibited increased monolayer permeability as measured by ECIS, in a time dependent-manner, with ~ 40% decrease in trans-endothelial resistance (TER) at 5 hr and ~50 % at 20 hr.”
This quote is telling us that researchers used 100 mg/mL pure liquid nicotine along with other solutions of nicotine and continuously exposed that solution to cultured Petri dish rat lung cells at a rate of 5 hours and 20 hours in order to show lung barrier cell damage. They eventually do use vapor, in which I will show you next, that shows e-Cig vapor does not cause lung cell necrosis, or death.
Question: Is this the same as popcorn lung that people associate with vaping?
Line 37-38: “Although nicotine at sufficient concentrations to cause endothelial barrier loss did not trigger cell necrosis, it markedly inhibited cell proliferation.”
Researchers are saying nicotine at sufficient concentrations did not trigger cell necrosis (death). In other words, nicotine does not kill your lung cells.
Line 267 – 269: “Given the relatively high concentrations of nicotine applied to cells in cultures, we ensured that the nicotine effect on the endothelium was not due to cell toxicity/necrosis, as determined by LDH release (data not shown).”
Once again, researchers are admitting to using a high concentration of nicotine (exact amount not shown) and applying the “relatively high concentration” to cells in cultures. They go on to say that they ensured the nicotine effect on the lung barrier cells was not due to cell toxicity/necrosis, or cell death. However, they don’t show the data.
Line 426 – 428: “The clinical implications of this work are related to the potential detrimental lung effects of exposure to inhaled e-Cig which may be dose-dependent, although further studies are needed to determine what are the usual levels of absorbed e-Cig vapor that are harmful to human lung health.
What the researchers are telling us here is that further studies are needed to determine what levels of absorbed e-Cig vapor are needed to show human lung cell damage and harm. When researchers state, “further studies are needed to determine what are the usual levels of absorbed e-Cig vapor that are harmful to human lung health”. I read this as researchers haven’t “proved” that e-Cig vapor is harmful to human lung health. They are stating that further studies are needed to determine this.
After multiple readings of this study, I came to my own conclusion that unrealistic conditions were used in order to show lung cell barrier harm. In one part of this study, researchers used 100 mg/mL nicotine extract and exposed it to lung cells in order to find that nicotine is harmful to lung barrier cells.
For those who don’t know, 100 mg/mL nicotine solution is not what is vaped by people who use e-cigarettes. 100 mg/mL nicotine solution is the highest commercially available to the public nicotine solution and is used by e-liquid manufacturers as a base nicotine solution which is diluted heavily with the other ingredients found in e-liquid which are Propylene Glycol, Vegetable Glycerin, and food flavorings to make the finished e-liquid product that vapers inhale. Vapers never inhale 100 mg/mL nicotine solution.
If you were to inhale 100 mg/mL nicotine solution, it would be unbearable and would cause nicotine overdose in the human body. To put it into perspective, e-liquid manufacturers commonly manufacturer their product at levels found between 0 mg/mL nicotine and 24 mg/mL nicotine, which the most common e-liquid being 12 mg/mL or lower.
If you were to even get a raindrop sized droplet of 100 mg/mL nicotine on your skin, it can cause symptoms of acute nicotine overdose which include nausea, vomiting, and rapid heartbeat. This is why people who mix e-liquid and handle nicotine in the 100 mg/mL use gloves, goggles, and other safety measures.
The study can be found here.
Did this study show that nicotine can cause damage to lung barrier cells? Read the study, and you be the judge.
Disclaimer: I am not a doctor, nor a scientist. The above expressed views are those of mine only. Please read the study to make your own conclusion.