Hepatic myofibroblasts constitute a heterogeneous population of highly proliferative,
pro-fibrogenic, pro-inflammatory, pro-angiogenic and contractile cells that sustain
liver fibrogenesis and then fibrotic progression of chronic liver diseases of different
aetiology to the common advanced-stage of cirrhosis. These alpha-smooth muscle actin-positive
myofibroblast-like cells, according to current literature, mainly originate by a process
of activation and trans-differentiation that involves either hepatic stellate cells
or fibroblasts of portal areas. Hepatic myofibroblasts can also originate from bone
marrow-derived cells, including mesenchymal stem cells or circulating fibrocytes able
to engraft chronically injured liver, as well as, in certain conditions, by a process
of epithelial to mesenchymal transition involving hepatocytes and cholangiocytes.
Hepatic myofibroblasts may have also additional crucial roles in modulating immune
response and in the cross talk with hepatic progenitor (stem) cells as well as with
malignant cells of either primary hepatocellular carcinomas or of metastatic cancers.