A type of immune cell quickly moves into the liver to aid tissue repair — but the cells come from the surrounding cavity, not from the blood.

Immune cells responding to injury have long been thought to migrate into tissues from the bloodstream. Some of these cells then mature into macrophages over 2–3 days to help heal wounds. Jing Wang and Paul Kubes at the University of Calgary in Canada used microscopes to follow macrophages over time in live mice that had sustained a liver injury. They found that mature macrophages moved into the liver from the surrounding cavity within just one hour. There, the macrophages helped to clear the injured area of dying cells so that new blood vessels could grow.

The team identified the molecular signals that drove this process, and suggest that it could occur in liver infection and in diseases such as cancer.

Cell http://doi.org/bd8b (2016)