Periportal macrophages protect against commensal-driven liver inflammation. (https://pubmed.ncbi.nlm.nih.gov/38658756/)
These scientists wanted to understand how the immune system works in different parts of the liver, which is like the main entrance from the gut in our body. They found that there are special areas in the liver where the immune responses are not as strong, called the periportal vein zones. They used a special camera to watch live images inside the liver and discovered that certain immune cells called macrophages in these zones are really good at calming down inflammation.
These macrophages produce a substance called interleukin-10 and have a special receptor called Marco that helps them catch harmful molecules that can cause inflammation. The scientists also found out that these calming macrophages are influenced by the bacteria living in our gut. One specific type of bacteria called Odoribacteraceae produces a substance that helps these macrophages do their job better.
When there are problems with the gut barrier, it can lead to inflammation in these periportal vein zones of the liver. In conditions like primary sclerosing cholangitis and non-alcoholic steatohepatitis, there are fewer of these calming macrophages. When the scientists removed these macrophages in animal experiments, they saw more inflammation and liver problems similar to these diseases.
In simple terms, the scientists discovered that certain good bacteria in our gut help special immune cells in the liver keep inflammation under control. When this system doesn't work well, it can lead to liver diseases.
Miyamoto Y., Kikuta J., Matsui T., Hasegawa T., Fujii K., Okuzaki D., Liu YC., Yoshioka T., Seno S., Motooka D., Uchida Y., Yamashita E., Kobayashi S., Eguchi H., Morii E., Tryggvason K., Shichita T., Kayama H., Atarashi K., Kunisawa J., Honda K., Takeda K., Ishii M. Periportal macrophages protect against commensal-driven liver inflammation. Nature. 2024 May;629(8013):901-909. doi: 10.1038/s41586-024-07372-6. Epub 2024 Apr 24.