התחדשות הכבד

In vertebrates, the liver is the only organ that can regenerate after injury, infection, or partial surgical removal.

Approximately 80% of the liver mass is hepatocytes — cells responsible for most liver functions. These cells remain in the G0 phase of the cell cycle unless stimulated.

Upon injury, Kupffer cells — phagocytic cells lining specialized capillary channels in the liver, release IL-6 and TNF-α. These cytokines induce hepatocytes to express c-MET and EGF receptors on their cell surface.

Then, the local stellate cells and the duodenum release hepatocyte growth factors and epidermal growth factors. 

HGF and EGF enter the injury site through the bloodstream to bind their receptors, c-MET and EGFR, on the primed hepatocytes.

As a result, the hepatocytes overcome the G0/G1 cell cycle checkpoint and start proliferating at the injury site to heal the damaged tissue.

Once the necessary organ size and tissue architecture are restored, stellate cells release TGF-β to block hepatocyte proliferation and terminate regeneration.