Sinusoidal remodeling and angiogenesis: A new function for the liver-specific pericyte?

Sonic hedgehog is an autocrine viability factor for myofibroblastic hepatic stellate cells

“…Cirrhotic livers also exhibit varying degrees of architectural distortion related to changes in hepatic sinusoidal structure, parenchymal nodularity, and accumulation of hepatic progenitors. These structural alterations are generally accompanied by some degree of organ dysfunction [3][4][5]. Cancers of bile ductular cells and hepatocytes also occur most often in the context of cirrhosis [6].…”

Angiogenesis: multiple masks in hepatocellular carcinoma and liver regeneration

“…Relative to the endothelial cells in other organs, LSECs have a unique phenotype characterized by forming a discontinuous, fenestrated endothelium without an organized basement membrane [21]. As the mural cells of the hepatic sinusoidal, HSCs are liver-specific pericytes [22,23]. Cellular cross-talk among LSECs, HSCs and hepatocytes is believed to play an important role in physiologic angiogenesis during liver regeneration.…”

“…Ang-1 regulates vessel stability by activating Tie-2, while Ang-2 acts as a natural antagonist of Ang-1 [22]. Tie-1 has an important role in endothelial cell differentiation and the maintenance of blood integrity [40,41].…”

“…HSCs expresses angiopoietins [22]. It has been suggested that Ang-1 binds to Tie-2 on the surface of endothelial cells and promotes interaction between endothelial cells and pericytes to stabilize the mature vascular system [46].…”

“…Arterialization can induce a partial transition of LSECs to capillary-type endothelial cells (sinusoidal capillarization) [60]. Sinusoidal capillarization is stimulated by Ang-1 due to hypoxia [22]. Subsequently, the progressing sinusoidal capillarization leads to an impairment of oxygen diffusion from the sinusoidal to hepatocytes [61,62].…”