Dr. Ayşegül Çoruhlu
Smoking – nicotine – COVID-19
these three words in the same sentence?
We have read the statistics bringing up the question “Do smokers pull through COVID-19 more easily?” and the news that France will try the nicotine patch as part of the treatment.
How should we interpret this? It has been proven by long-term medical research and is inarguable that smoking does not have any health benefits. Our topic here is not smoking.
Our topic is nicotine substance. And to review whether taking nicotine from the outside by patches will benefit.
What is nicotine, does it have a place in lung health?
First of all, let’s tell you exactly what nicotine does.
Nicotine acts by binding to one of two receptors of a substance called acetylcholine.
Apart from the nervous system, acetylcholine is present in the lung. In the lung epithelium, acetylcholine is found in fighter macrophages of the lung. As a regulator of the nervous system, acetylcholine regulates parasympathetic nervous system activity in the lung. For example, being able to contract the bronchi of the lung is related to acetylcholine.
Acetylcholine has two receptors. One is the muscarinic receptor and the other is the nicotinic receptor.
The muscarinic receptor is responsible for the contraction of the bronchi. The muscarinic receptor contracts the lungs. The muscarinic receptor also plays a role in the secretion of mucus. It also increases the secretion of mucus when an infectious agent or allergic agent comes. It shows these effects in allergic asthma. It stimulates the immune system response, called the Th2 response, which increases in allergic reactions. It increases cytokine release. It also increases the production of interleukin 6 and other inflammatory cytokines. Lungs are tried to be relaxed by giving muscarinic receptor antagonists to those with allergic asthma.
Let’s come to nicotinic receptors. Of the nicotinic receptors, especially alpha 7 nicotinic receptors act as the opposite of muscarinic receptors.
It prevents inflammation and reduces mucus secretion. It reduces allergic responses. It reduces the cytokine response of macrophages, which are defense cells.
The presence of nicotine activates the nicotinic receptors of acetylcholine. We call this an agonistic effect. Thus, muscarinic receptor-induced effects are reduced.
Perhaps for these reasons, the situation in smokers among COVID-19 patients can be explained. That is the reduction in the muscarinic receptor effect and inflammation and the increase in nicotinic receptor-mediated anti-inflammatory effect instead.
A second explanation may be the number of ACE2 receptors.
Some of the publications after COVID-19 state that smoking increases the number of ACE2 receptors, which is true in that: the hypoxia, in other words oxygen deficiency, that smoking creates, not nicotine, may cause this. The goal of ACE2 is to convert Angiotensin 2 to angiotensin 1-7. While Angiotensin 2 causes hypertension and vascular narrowing, angiotensin 1-7 does the opposite oof this and relaxes the vessels. The vascular damage and oxygen shortage caused by smoking may be attempted to be eliminated through Angiotensin 1-7 by increasing the number of ACE2.
However, the publications before COVID-19 mention nicotine, not smoking, and exact opposite results.
In other words, they state that the presence of nicotine (nicotine substance, not smoking) reduces the number of ACE2. The decrease in the number of ACE2 may decrease viral entry. This may be a positive effect on nicotine.
Ultimately, it will be examined whether the beneficial substance will be nicotine or not. In my opinion, low-dose nicotine can be used as a brain stimulant in neurological diseases. In COVID-19, it seems useful to activate the nicotinic receptors instead of the muscarinic receptors of acetylcholine.
What was already weird was that while smoking is so harmful, smokers do not sneeze like allergic individuals, do not produce much sputum. The great harm of smoking spreads over the years; the fact that nicotine keeps the environment slightly quiet may have been a factor in individuals to smoke for a long time without complaints.
However, let us remember that although the short-term use of nicotine patch has been attempted as a research subject, the ‘immune response’ suppressed by nicotine insidiously increases canceration in lung cells in the long term.
There are many publications on this topic. I put two of them below.
Let’s finish with nature. Let’s come to the eggplant that contains nicotine. If you eat 20 eggplants, it corresponds to the amount of nicotine in 1 cigarette. But if we add its purple color, being vegetable, high antioxidant value, we can consider eggplant, which is already precious, even more precious with its nicotine.