Hepatic stellate cell in the cell body store vitamin A as retinol ester. The function and role of quiescent hepatic stellate cells is unclear. Recent evidence suggests a role as a liver-resident antigen-presenting cell, presenting lipid antigens to and stimulating proliferation of NKT cells. When the liver is damaged, stellate cells can change into an "activated" state. The activated stellate cell is characterized by proliferation, contractility, and chemotaxis. This state of the stellate cell is the main source of extracellular matrix production in liver injury. This attribute makes it a key factor in the pathophysiology of the liver. The amount of stored vitamin
Organ-on-a-chip models that replicate aspects of the human body as closely as possible and give examples that demonstrate their potential use in drug development, such as identifying synergistic drug interactions as well as simulating multi-organ metabolic interactions. Multi compartment micro fluidic-based devices, particularly those that are physical representations of physiologically based pharmacokinetic (PBPK) models that represent the mass transfer of compounds in compartmental models of the mammalian body, may contribute to improving the drug development process. Mathematical pharmacokinetic (PK) models aim to estimate concentration-time profiles within each organ on the basis of the initial drug dose. Such mathematical models can be