The liver has a rare superpower among body organs—the ability to regenerate, even if 70% of its mass is removed. It also keeps up its metabolic and toxin-removing work during the process of regeneration, thanks to a subset of cells that expand their workload while the rest focus on multiplication, a new study in mice found. They identified a specific class of cells that do not proliferate, but instead ramp up their metabolic function, taking on a greater workload. Meanwhile, the regenerating cells multiplied in a coordinated manner, starting from the middle regions and progressing outward toward the liver's periphery—contrary to prevailing theories in the field that proliferation begins near the veins.

The researchers found that the regeneration and metabolic activities were coordinated through extensive cell-to-cell communication. The communication dramatically increased after part of the liver was removed, but by the time regeneration slowed and stopped, the signalling had gone back down toward base levels.

In studying the coordination between cells, they also found a possible explanation for how the regeneration process regulates itself so the liver stops growing when it reaches its original size. Mature liver cells had an abundance of receptors on their surfaces that were activated by molecules their neighboring cells released after surgery, triggering the cells to become neonatal-like and divide. During the proliferation process, however, the cells stopped expressing the receptors, allowing them to return to a mature state when division was complete.

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John
Editorial Assistant
Immunogenetics Open Access