Activin A resistant fetal liver stem/progenitor cells (FLSPC) vigorously repopulate aging rat liver through augmented cell competition

Recently, we showed that highly proliferative FLSPC repopulate the normal young recipient liver by out-competing less proliferative host hepatocytes (HC) by inducing their apoptosis. The aim of the study was to discover the mechanism through which FLSPC are capable to repopulate the recipient liver and more effectively repopulate the liver of aging rats. We observed a 4–5fold increase of liver repopulation after FLSPC transplantation into rats of advancing age. In aging liver, mRNA expression of cyclin-dependent kinase inhibitors increased progressively, most notably p15INK4b, a gene recently reported to be a de…