Research discovers new bacteria which can digest nicotine in smokers

• Scientists in Beijing have discovered a bacteria which can degrade nicotine found in cigarettes. 
• This bacterium named Bacteroides xylanisolvens is a natural commensal found in the gut of all humans. 
• It can prevent the progression of liver disease in smokers that occurs due to nicotine accumulation. 

Scientists at the School of Basic Medical Sciences, in collaboration with other organizations at Peking University, in Beijing, have made a startling discovery concerning the progression of liver disease in smokers.

Not only has the team confirmed the mechanism of the progress of liver disease in smokers but they have also identified a common gut bacteria which may help to decrease toxic levels of nicotine in such people.

What is NAFLD? 

First and foremost to understand the research model presented by the scientists in Beijing, one must understand the progression of liver disease in smokers.

As we know that most chronic smokers have a really tough time kicking this deadly habit, but why is that so? Why is smoking so addictive for the habituated?

This is due to the presence of a certain chemical known as nicotine present in cigarettes. This chemical which is an alkaloid acts as both a stimulant and an anxiolytic.

Meaning when nicotine is absorbed into one’s bloodstream, it stimulates the adrenal glands just above the kidney to release adrenaline. Adrenaline increases your blood pressure, breathing, and heart rate. Adrenaline also gives one a lot of good feelings all at once.

Now, where does the liver come in? Well, the liver is the organ of detoxification in our body. That means all the chemicals we consume or are produced in the body are further processed in the liver before excretion.

With respect to nicotine, when it is metabolized by the liver, it adversely affects the organ by releasing toxins and causing inflammation.

Furthermore, previous studies have confirmed that it also leads to liver injuries, triggers the formation of excessive connective tissues and red blood cells, and increases the risk of diseases like blood cancer and non-alcoholic fatty liver disease (NAFLD) in humans.

As a result of NAFLD, the affected liver becomes enlarged called hepatomegaly, undergoes yellowish discoloration, and may look greasy or slimy. Patients may have jaundice as well.

What is NASH? 

The next step in the progression of liver disease in smokers already suffering from NAFLD is NASH(non-alcoholic steatohepatitis). NASH can get worse and cause scarring of the liver, which leads to cirrhosis and may be fatal.

Until now the exact mechanism of progression of NAFLD to NASH was unknown, that is till the scientists in Beijing published their hypothesis.

They used two models- one mouse and the other human to confirm that nicotine accumulation in the gut of chronic smokers stimulates the NAFLD in such patients to deteriorate to NASH.

The study experimented with one group of mice who were exposed to nicotine and compared nicotine levels in their serum and stool samples with another group of normal mice. Nicotine levels were found to be higher in mouse models that were exposed to nicotine.

The same experiment was repeated with two groups of humans each 30 in number. Again examination of stool and serum samples revealed greater nicotine accumulation in the group of regular smokers.

In their research manuscript published in the Nature journal, the team suggests that nicotine accumulates in the intestine during tobacco smoking and activates intestinal AMPKα which ultimately contributes to NAFLD progression to NASH.

The friendly gut savior 

The research also successfully identified a common gut bacteria which is present as a commensal in the alimentary canal as a solution to the problem.

This bacterium named Bacteroides xylanisolvens acts as an effective nicotine degrader. Thus it can be an effective tool to prevent nicotine accumulation in the gut of chronic smokers and be protective against progressive liver disease in such patients.

This discovery opens up the greater scope of research into how to enhance the colonization of Bacteroides in the intestine to utilize its properties.