Human thoracic duct lymph inhibits lipopolysaccharide-induced release of cytokines

Oral starvation causes gut atrophy and breakdown of barrier function, which can lead to transport of lipopolysaccharide (LPS) across the intestinal mucosa. Since triglyceride-rich lipoproteins can inhibit lipopolysaccharide-induced cytokine release, it can be hypothesized that enteral feeding protects the body against translocated LPS at the level of the thoracic duct by increasing the levels of triglycerides in thoracic duct lymph. We sought to determine the LPS-neutralizing capacity of human chyle by measuring LPS-induced cytokine production in vitro in the presence or absence of thoracic duct lymph. Moreover, we assessed whether enteral administration of triglyceride-rich lipoproteins changed the ability of lymph to influence LPS activity. Indeed, the presence of 10% and 100% triglyceride-poor and triglyceride-rich lymph induced a significant reduction in the TNF and IL-6 production elicited by LPS. However, there was no difference in the extent of inhibition of cytokine-release by triglyceride-poor and triglyceride-rich lymph. This study shows that lymph can inhibit LPS activity. This is not affected by prior enteral administration of triglycerides.