Quit Smoking: The enzyme puts an end to nicotine addiction in the rat without withdrawal symptoms

Scientists have developed an enzyme that could help people quit smoking and has been successfully tested on rats. Although its potential treatment of human nicotine addiction is far from satisfactory, researchers believe that it could be turned into a pill that prevents smokers from missing the drug – and potentially without any symptoms of weaning.

The scientists conducted an experiment in which two groups of rats were trained to self-administer nicotine in two weeks. Their nicotine consumption has increased, indicating an addiction.

One of these groups then received the enzyme and the other did not. Both groups were still able to self-administer nicotine.

In the group of enzymes, rats were administered various levels of NicA2-J1. This enzyme breaks down nicotine, which means that drug levels in the blood are reduced. The researchers found that at higher levels, the enzyme caused a decrease in nicotine intake. The rats also did not exhibit withdrawal symptoms or "irritability-like" behavior.

The results, published in Progress of science, indicate that the enzyme is effective in the treatment of nicotine addiction in animal models and could be further developed for human use.

Representative image of the laboratory rat. The rats that received the nicotine degrading enzyme exhibited less addictive behaviors. iStock

It is estimated that nearly 28 million American adults smoke cigarettes. About 16 million people currently live with a smoking-related disease and reducing smoking rates is a major public health problem. Progress is being made, however, with rates rising from 20% in 2005 to 15% in 2016, but this remains a major problem across the country. It is estimated that, if current trends continue, 5.6 million children in the United States today will die prematurely of a smoking-related disease.

The research was led by Marsida Kallupi and Olivier George of the Scripps Research Institute in California. George told Newsweek that they will have to do more research on the mice to make sure the enzyme is not toxic and modify it accordingly, if necessary. He also said he hoped that this will eventually pass to human testing.

"So far, no major toxic effects have been observed, so we are very optimistic," he said. "The biggest obstacle is not scientific here, it's really to find the funding that will allow us to take this approach to the clinic … once the funding is secured, I expect we will make very fast progress."

Representative Image It is estimated that nearly 28 million American adults smoke cigarettes. iStock

"The idea here would be for smokers who want to quit to take a pill every week or so in order to maintain high levels of enzyme in the blood and continue smoking at the beginning. Since the enzyme will trap most of the nicotine, it will gradually become less and less dependent on nicotine without being weaned and will find the cigarette less and less attractive. Our data shows that people who follow this protocol have a greater chance of quitting and a lower risk of relapse. Even if they stopped completely, they would continue to take the enzyme in case they made a mistake to make sure that it would not cause a complete relapse. "

He said the lack of withdrawal in the rats was a huge surprise. They believe that this could have happened because the enzyme leaves a tiny trace of nicotine in the blood, which could be enough to dispel withdrawal symptoms until the level of addiction is negligible.

If this translates into humans, it could help smokers to skip the withdrawal phase and prevent relapse. "There are many studies showing that smokers who switch to nicotine-like cigarettes do not like it and end up returning to their favorite nicotine-like cigarette," George said. "The beauty of our enzymatic approach is that the enzyme would make every cigarette denicotinated, there would be no possibility of cheating as long as you take the pill."