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An engineered enzyme can make quitting smoking easier

Lab rats who were administered the enzyme displayed reduced levels of irritability and other symptoms associated with nicotine withdrawal
by TR Pakistan

Scientists at Scripps Research Institute (SRI) have engineered an enzyme that could make it easier for smokers to deal with nicotine withdrawal, and finally put away the stinkies. The enzyme — named NicA2-J1 — was isolated from the bacteria Pseudomonas Putida S16. It was found to effectively degrade nicotine in the bloodstream, preventing it from reaching the brain.

Administration of the enzyme to nicotine-dependent rats also resulted in cessation of nicotine withdrawal symptoms such as hyperalgesia (enhanced pain response) and irritability.These findings were published online in the journal Science Advances earlier this month.

“This is a very exciting approach because it can reduce nicotine dependence without inducing cravings and other severe withdrawal symptoms, and it works in the bloodstream, not the brain, so its side effects should be minimal,” said the study’s principal investigator Olivier George.

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In the study, lab rats were put in a chamber for 21 hours a day for 12 days. They had access to a lever which gave them an intravenous infusion of nicotine. Eventually, they learnt how to self administer and became addicted. Once the 12-day period was over, they were only given access after 48 hours, which led them to experience withdrawal symptoms. It was found that withdrawal led them to administer more nicotine when they were eventually given access to it, which is a sign of deepening addiction.

Though the rats with the most chronic addiction continued to self administer nicotine after being given the enzyme, they still showed very low nicotine levels in in the blood. In turn, this reduced the level of addiction and thus they also showed lowered responses to nicotine withdrawal.

As such, NicA2-J1 is not a cure to nicotine addiction, but it can alleviate the most uncomfortable symptoms associated with nicotine withdrawal. The Scripps research team hopes to take the enzyme into clinical trials with humans soon.

Tobacco use disorder remains the leading cause of preventable death worldwide. The relapse rate among smokers who attempt to quit also remains high, with up to 80 percent unable to continue abstaining from smoking within the first 12 months of quitting.


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