Cell 134, 657–667 (2008)10.1016/j.cell.2008.06.049

Although senescent cells may appear dormant, they have an important role in protecting the liver from cirrhosis, according to Scott Lowe of Cold Spring Harbor Laboratory in New York and his colleagues.

Cirrhosis results from the long-term accumulation of fibrous scar tissue. Lowe and his team discovered that senescent cells accumulate in cirrhotic livers and form the structural basis for fibrosis. The researchers then gave a liver-damaging compound to mutant mice that lacked a protein required for senescence. These animals suffered more liver fibrosis than normal mice.

Other experiments revealed that senescent cells seem to attract the attention of immune cells called natural killer cells. These target the senescent cells for destruction, aiding in a partial recovery from liver fibrosis.