NO nasal spray?

Could it be a potential cure for Covid?
24 February 2022

Interview with 

Louis Ignarro


An image showing the arteries and veins in the lungs.


Nitric Oxide (NO) relaxes the innter muscles of the blood vessels, allowing them to widen and circulate blood around the body. It is produced naturally by most, with those who struggle to produce enough NO suffering from a condition called pulmonary hypertension. Getting NO into your body can be tricky given its reaction with oxygen in the air, and so scientists have had to get creative to try and solve this particular problem. Lou Ignarro tells Chris Smith all about it...

Lou - I'm not sure exactly how much more can be told until these experiments and trials are really completed. Let me start by explaining really that NO or nitric oxide is a very unstable gas. In the presence of the oxygen in the air, the half-life of nitric oxide is about 1 second. You cannot put nitric oxide gas into a nasal spray and deliver nitric oxide. It would be delivered as nitrogen dioxide, which is not too healthy for you. Now, there are a number of small companies trying to develop chemicals like nitrites and nitrates. The same sorts of molecules found in green, leafy vegetables and beets and beet juice, and so on. If you put that in a nasal spray and you spray it, then the nitrite and the nitrate can somewhat be converted to nitric oxide, which you can then inhale. But to the best of my knowledge, this is not an effective way to deliver pure NO into your lungs, the only way we know how to do that is to inhale nitric oxide. That's where the idea of the nasal spray came. For 20 years in the clinic, there are gadgets that can produce nitric oxide as needed, mix it with the air and the patients breathe it in, and it works. The nitric oxide gas gets into the lungs and this has been used to treat infants and new-borns with persistent pulmonary hypertension and save their lives. Also, this kind of inhaled nitric oxide has been successful in treating COVID.

Chris - There have been a lot of observations that people who have heart disease and high blood pressure tend to come off worse. Do you think that your molecule, nitric oxide, is bound up in that observation and the fact that people are trying this as one way to minimise the impact of COVID is linked as well?

Lou - Yes, there's no question about it. First of all, in COVID the problem is that the coronavirus or the strains of it, all must get into the lungs. They attach to the alveoli where there's oxygen exchange and blood flow and these viruses destroy the inner linings of the arteries. It's called the endothelium lining and those are the cells that make nitric oxide. We make nitric oxide everywhere, but in our lungs we make it for several reasons. To dilate the arteries, so that more blood flows through the lungs and can therefore pick up more oxygen. Nitric oxide is also a fantastic antiviral agent. Nitric oxide will destroy many different viruses, especially the coronavirus, in the lungs and prevent their spread. Also nitric oxide deficiency is associated with all kinds of cardiovascular diseases, coronary artery disease, or atherosclerosis in other parts of the body, and so on. If you decrease it further, you're going to have problems. Patients with covid who have some cardiovascular problems, their cardiovascular problems are going to get a lot worse.


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