Impact of the type of bacteria on high-density lipoprotein cholesterol level during sepsis

High-density lipoproteins (HDL) are nanoparticles that enable the reverse transport of cholesterol and have multiple endothelioprotective properties that may play a role in sepsis, where HDL-cholesterol (HDL-C) concentrations typically plummet, which is strongly linked to poor outcomes. While HDL has the capacity to capture and eliminate lipopolysaccharides (LPS), which may explain this decrease in HDL-C concentration, this effect is less clear for Gram-positive bacteria via binding to lipoteichoic acid (LTA). The aim of this study is to determine whether the type of bacteria influences HDL-C concentrations in septic patients. This was a prospective, observational, single-center study of septic patients hospitalized in the intensive care unit (ICU). Patients were stratified into three groups according to the type of bacterial sepsis: infections caused by one or more Gram-negative bacteria, infections caused by one or more Gram-positive bacteria, or mixed infections involving both Gram-negative and Gram-positive bacteria. A total of 202 patients were prospectively and consecutively included in this study. HDL-C concentrations were below reference values. Additionally, there was no association between the type of bacteria and clinical outcomes. Interestingly, baseline HDL-C concentrations were similar between groups. HDL-C concentrations are low in septic conditions, and there is no relationship between HDL-C levels and the type of bacteria, which may indirectly support the scavenger action of HDL particles on all types of bacteria, including Gram-positive. Before conducting a phase 3 trial comparing recombinant HDL injection versus placebo during sepsis to improve HDL levels, further mechanistic studies are needed.