Impact of bacterial DNA in severity of sepsis

Abstract

Bacterial sepsis can be caused by intestinal damage, leading to the passage of viable bacteria and their components into the circulatory system. Bacterial-free DNA in the blood during sepsis can be derived from bacterial death and intestinal translocation of free DNA in the gut contents. The presence of bacterial DNA in combination with lipopolysaccharide (LPS) can lead to more serious outcomes of sepsis. To explore the impact of bacterial-free DNA in sepsis, animal and macrophage experiments were performed. Firstly, the appearance of bacterial-free DNA and bacteriome in the blood was presented in mice with cecal ligation and puncture sepsis. Secondly, injection of LPS with bacterial-free DNA in mice was more severe than LPS injection alone. Finally, the increased TNF-α, IL-6, and IL-10 cytokine, and several pro-inflammatory genes (iNOS and IL-1β) in macrophages support the synergy between bacterial DNA and LPS. In conclusion, the presence of bacterial-free DNA in sepsis was partly due to the degradation of viable bacteria in blood and the translocation of free DNA from the gut contents resulted in the profound inflammation. These data support the importance of free DNA in the blood during sepsis.