Extracellular Vesicle microRNA Biomarkers of Late Post-sepsis Survivors

Abstract

Sepsis is a life-threatening condition with high hospital mortality. Elevated mortality has also been observed in patients after hospital discharge due to post-sepsis syndrome (PSS). The etiology of PSS is still not entirely known, but it involves inflammation. Plasma extracellular vesicles (EVs) are recognized as a unique mechanism of intercellular communication in inflammatory processes. It has been reported that EV microRNA (miRNA) production during the acute sepsis phase may persist until after disease resolution and is associated with PSS.
 We employed mass spectrometry and qPCR analysis to determine the protein and miRNA composition of plasma-derived EVs of 36 patients during sepsis-related hospitalization, immediately after ICU discharge (post-sepsis), and three, six, twelve, and up to 36 months post-sepsis.
 We determined that patients’ immune system cells were the primary EV source. Fifteen differentially expressed EV miRNAs (DEmiRs) were identified in samples from septic patients compared to the control group. Predictive analyses revealed that these DEmiRs could influence inflammation by modulating pathways mediated by NF-κB, STAT3, and TLR4 signaling activation. Thirteen miRNAs (-15b-5p,-16-5p,-20a-5p,-25-3p,-27a-3p,-29a-3p,-30d-5p,-93-5p,-146a-5p,-148a-3p,-191-5p,-195-5p,-223-3p) were downregulated in the death group compared to the survivor group, making them candidate prognostic markers of ICU survival. One year after ICU discharge, the expression of miR-21-5p and miR-195-5p were decreased in the survivor group. 
 The miRNAs identified in the present study represent potential biomarkers for the survival prognosis of post-sepsis patients.