Early increase in anti-inflammatory biomarkers is associated with the development of multiple organ dysfunction syndrome in severely injured trauma patients

Innate Neutrophil Memory Dynamics in Disease Pathogenesis

Neutrophils, the most abundant leukocytes in circulation and the first responders to infection and inflammation, closely modulate both acute and chronic inflammatory processes. Resting neutrophils constantly patrol vasculature and migrate to tissues when challenges occur. When infection and/or inflammation recede, tissue neutrophils will be subsequently cleaned up by macrophages which collectively contribute to the resolution of inflammation. While most studies focus on the anti-microbial function of neutrophils including phagocytosis, degranulation, and neutrophil extracellular traps (NETs) formation, recent research highlighted additional contributions of neutrophils beyond simply controlling infectious agents. Neutrophils with resolving characteristics may alter the activities of neighboring cells and facilitate inflammation resolution, modulate long-term macrophage and adaptive immune responses, therefore having important impacts on host pathophysiology. The focus of this chapter is to provide an updated assessment of recent progress in the emerging field of neutrophil programming and memory in the context of both acute and chronic diseases.

Alarming Cargo: The Role of Exosomes in Trauma-Induced Inflammation

Severe polytraumatic injury initiates a robust immune response. Broad immune dysfunction in patients with such injuries has been well-documented; however, early biomarkers of immune dysfunction post-injury, which are critical for comprehensive intervention and can predict the clinical course of patients, have not been reported. Current circulating markers such as IL-6 and IL-10 are broad, non-specific, and lag behind the clinical course of patients. General blockade of the inflammatory response is detrimental to patients, as a certain degree of regulated inflammation is critical and necessary following trauma. Exosomes, small membrane-bound extracellular vesicles, found in a variety of biofluids, carry within them a complex functional cargo, comprised of coding and non-coding RNAs, proteins, and metabolites. Composition of circulating exosomal cargo is modulated by changes in the intra- and extracellular microenvironment, thereby serving as a homeostasis sensor. With its extensively documented involvement in immune regulation in multiple pathologies, study of exosomal cargo in polytrauma patients can provide critical insights on trauma-specific, temporal immune dysregulation, with tremendous potential to serve as unique biomarkers and therapeutic targets for timely and precise intervention.

Neutrophil-derived long noncoding RNA IL-7R predicts development of multiple organ dysfunction syndrome in patients with trauma

PURPOSE

Overactive neutrophils are thought to be key drivers in the development of post-traumatic multiple organ dysfunction syndrome (MODS). Little is known about the role of inflammation-related lnc-IL7R in trauma. Thus, we aimed to explore the association between neutrophil-derived lnc-IL7R and post-traumatic MODS.

METHODS

Total RNA was extracted from the isolated circulating neutrophils in 60 patients with trauma and 33 healthy volunteers for lnc-IL7R expression determination by real-time PCR. The correlation of lnc-IL7R expression with disease severity and the development of post-traumatic MODS was analyzed.

RESULTS

The lnc-IL7R levels were significantly lower in trauma patients, especially in those with severe trauma [Injury Severity Score (ISS) ≥ 16], and correlated negatively with the ISS, Acute Physiology and Chronic Health Evaluation II score, and length of ICU stay. The lnc-IL7R levels were also significantly decreased in patients who developed MODS than in those who did not. Lnc-IL7R was an independent predictor of MODS [odds ratio (OR) 0.654, (0.435-0.982), p = 0.041]. The area under the curve for predicting post-traumatic MODS was 0.799 (sensitivity 76.9%, specificity 71.4%), with a cutoff value of 0.024.

CONCLUSIONS

Neutrophil-derived lnc-IL7R is an independent predictor of post-traumatic MODS; therefore, it could be a useful predictive marker for MODS.