The October issue of the Journal of Leukocyte Biology includes an excellent review article on the issues surrounding endotoxemia and in detecting endotoxin in biological fluids. As is often the topic with this newsletter, the author begins by noting the relationship between circulating endotoxin and problems such as atherosclerosis, alcoholic liver disease, autoimmunity, metabolic syndrome, renal injury, obesity, depression, HIV disease and type 2 diabetes. In addition, the report highlights the variation in reports of the amount of circulating endotoxin in various disease and the correlation with cytokine levels.
The article highlights the heterogeneity of endotoxin, including how differences in acyl chains and phosphates on the Lipid A moiety can affect interactions with MD-2-TLR4 and thus potency. It also covers routes of endotoxin into the circulation and interactions with proteins (e.g., lipoproteins, LBP, albumin) in the bloodstream. The majority of the paper deals with methods of detecting endotoxin in biological samples and the limitations of each method. This includes LAL, ELISA and EAA.