A circulating lipoprotein that picks up cholesterol in the arteries and deposits it in the liver for reprocessing or excretion. HDL is often referred to as the "good cholesterol."

A type of lipoprotein. LDL is formed in the liver and transports lipid molecules to the cells. Often referred to as the “bad cholesterol,” LDL can drive the progression of atherosclerosis if it becomes oxidized within the walls of arteries. LDL particles exist in different sizes, ranging from large, fluffy molecules to small, dense molecules. Some evidence suggests that LDL particles increase the risk of developing heart disease, whereas the large, fluffy type of LDL may be cardioprotective.^[1]

Large molecules consisting of a lipid and a polysaccharide with an O-antigen outer core. Lipopolysaccharides are found in the outer membrane of Gram-negative bacteria and elicit strong immune responses in animals through pattern recognition conferred by a toll-like receptor known as TLR4. Even a low dose LPS challenge of 0.6 ng/kg body weight given intravenously can induce a profound, if transient, 25-fold and 100-fold increase in plasma IL-6 and TNF-alpha, respectively.^[1] Also known as bacterial endotoxin.