Metabolic endotoxemia is dictated by the type of lipopolysaccharide.

Abstract

Lipopolysaccharides (LPSs) can promote metabolic endotoxemia, which is considered inflammatory and metabolically detrimental based on Toll-like receptor (TLR)4 agonists, such as Escherichia coli-derived LPS. LPSs from certain bacteria antagonize TLR4 yet contribute to endotoxemia measured by endotoxin units (EUs). We found that E.coli LPS impairs gut barrier function and worsens glycemic control in mice, but equal doses of LPSs from other bacteria do not. Matching the LPS dose from R.sphaeroides and E.coli by EUs reveals that only E.coli LPS promotes dysglycemia and adipose inflammation, delays intestinal glucose absorption, and augments insulin and glucagon-like peptide (GLP)-1 secretion. Metabolically beneficial endotoxemia promoted by R.sphaeroides LPS counteracts dysglycemia caused by an equal dose of E.coli LPS and improves glucose control in obese mice. The concept of metabolic endotoxemia should be expanded beyond LPS load to include LPS characteristics, such as lipid A acylation, which dictates the effect of metabolic endotoxemia.