After partial hepatectomy, as a consequence of hepatocyte proliferation, cell clusters
containing 10–14 hepatocytes are formed. These clusters are devoid of sinusoids and
extracellular matrix; therefore, many hepatocytes are two to three cells removed from the
vascular spaces. Four days after hepatectomy, Ito cells send delicate cell processes
between the hepatocytes in the clusters. This “invasion” of the clusters coincides with the
activation in Ito cells of genes encoding for several laminin chains. The penetration of Ito …

After partial hepatectomy, the liver is capable of complete regeneration, restoring normal
hepatic size, architecture, and function. To study the role of the extracellular matrix in
regeneration, the temporal and spatial sequence of deposition of several of its components,
including collagen types I, III, and IV, laminin, and fibronectin, in rat liver, after an 80%
hepatectomy, was characterized by light microscopy immunohistochemistry. A minimum of
five animals were studied for each date. In agreement with previous reports, subsequent to …