Fenestrations in the Liver Sinusoidal Endothelial Cell

Liver sinusoidal endothelial cells (LSECs) occupy a strategic position in the liver, separating blood in the sinusoid from the extracellular space of Disse and surrounding sheets of hepatocytes. The cytoplasmic extensions of LSECs are very thin and perforated with patent pores called fenestrations, which lack diaphragms or underlying basal lamina. There are numerous reports of diseases and pathological processes that influence fenestrations, including: primary liver disease, liver toxins, systemic disease, and other liver processes. These changes have not usually been diagnostic but the overall trends are that: acute toxic injury and acute medical conditions are associated with loss of endothelial integrity characterized by gap formation and subacute and chronic conditions have been associated with defenestration and reduced porosity. The advent of exciting new microscopic techniques such as super-resolution microscopy has generated new knowledge about the biology of fenestrations.