Immortalized Human Hepatic Sinusoidal Endothelial Cells

The liver sinusoidal endothelium functions as a highly specialized vascular interface, where liver sinusoidal endothelial cells (LSECs) form a unique fenestrated barrier that lines the hepatic sinusoids and comprises the majority of endothelial cells within the liver. LSECs are distinguished by their lack of an organized basement membrane and the presence of transcellular fenestrae, which collectively ensure high vascular permeability and facilitate efficient bidirectional exchange of nutrients and solutes between the sinusoidal blood and the space of Disse. Beyond their role as a passive filtration barrier, LSECs actively participate in blood clearance via receptor-mediated endocytosis, immune surveillance, and the regulation of vascular tone. However, primary LSECs are notoriously difficult to obtain due to the scarcity of suitable liver resections, and their use for in vitro investigations is compromised by poor cell yields and a limited proliferation capacity, which severely restricts long-term mechanistic studies.

To overcome these limitations, human LSECs have been immortalized through stable introduction of immortalizing genes, including Simian Virus 40 large T antigen (SV40T), human telomerase reverse transcriptase (hTERT), or both. The immortalized cells retain key endothelial characteristics, expressing classic markers such as von Willebrand Factor (vWF), CD31, VE-cadherin, and stabilin family markers. They maintain functional LSEC features, including endocytosis of acetylated low-density lipoprotein (Ac-LDL), tube formation capacity, and immune reactivity. More importantly, they preserve the characteristic fenestrated morphology and Weibel-Palade bodies, as confirmed by scanning and transmission electron microscopy, while offering sustained expansion and experimental reproducibility essential for high-throughput studies.

Collectively, immortalized human LSECs provide an unlimited, consistent, and phenotypically faithful in vitro model for investigating LSEC physiology and pathobiology-including liver regeneration, infection, ischemia-reperfusion injury, and drug-induced hepatotoxicity-circumventing the inherent limitations of primary cell cultures.