Comparison of the source and prognostic utility of cfDNA in trauma and sepsis

Abstract

Background Circulating cell-free DNA (cfDNA) may contribute to the pathophysiology of post-injury inflammation and coagulation in trauma. However, the source and mechanism of release of cfDNA in trauma is not well understood. One potential source of cfDNA is from Neutrophil Extracellular Traps (NETs), released by activated neutrophils during the process of NETosis. The primary objective of our study was to determine if cfDNA has prognostic utility in trauma. The secondary objective of this study was to determine the source of cfDNA in trauma compared to sepsis. Methods We studied trauma patients from two prospective observational cohort studies: the DNA as a Prognostic Marker in ICU Patients (DYNAMICS) study and the Endotoxin in Polytrauma (ENPOLY) study. We also studied septic patients from the DYNAMICS study. Citrated plasma samples were collected longitudinally from the patients (days 1 to 7). The following molecules were measured in the plasma samples: cfDNA, protein C (PC), myeloperoxidase (MPO) (a marker of neutrophil activation), citrullinated Histone H3 (H3Cit, a marker of NETosis), cyclophilin A (a marker of necrosis), and caspase-cleaved K18 (a marker of apoptosis). Results A total of 77 trauma patients were included ( n = 38 from DYNAMICS and n = 39 from ENPOLY). The median age was 49 years; 27.3% were female, and mortality was 16.9% at 28 days. Levels of cfDNA were elevated compared to healthy values but not significantly different between survivors and non-survivors. There was a positive correlation between MPO and cfDNA in septic patients ( r = 0.424, p < 0.001). In contrast, there was no correlation between MPO and cfDNA in trauma patients ( r = – 0.192, p = 0.115). Levels of H3Cit, a marker of NETosis, were significantly elevated in septic patients compared to trauma patients ( p < 0.01) while apoptosis and necrosis markers did not differ between the two groups. Conclusion Our studies suggest that the source and mechanism of release of cfDNA differ between trauma and sepsis patients. In sepsis, cfDNA is likely primarily released by activated neutrophils via the process of NETosis. In contrast, cfDNA in trauma appears to originate mainly from injured or necrotic cells. Although cfDNA is elevated in trauma and sepsis patients compared to healthy controls, cfDNA does not appear to have prognostic utility in trauma patients. Trial registration ClinicalTrials.gov Identifier: NCT01355042 . Registered May 17, 2011 Electronic supplementary material The online version of this article (10.1186/s40635-019-0251-4) contains supplementary material, which is available to authorized users.

Circulating cell‐free DNA improves the molecular characterisation of Ph‐negative myeloproliferative neoplasms

“…Regarding the total amount of cfDNA, we observed that this value differs depending on the clinical or disease phenotype and genotype of patients. cfDNA is a variable parameter, that even in healthy individuals presents significant variations due to inflammation, injury or exercise 20–22 . However, irrespective of disease phenotype our MPN samples showed a significantly higher amount of cfDNA than those of healthy controls, indicating a higher release of cfDNA in plasma from MPN clonal cells.…”

Circulating Histones in Sepsis: Potential Outcome Predictors and Therapeutic Targets

“…Pan et al found that the level circulating H3Cit was significantly higher at 0.5, 3, 12, and 24 hours after LPS injection in LPS-treated mouse group than that in control group, revealing its potential ability as a sensitive and longlasting biomarker (86). Another observational study also showed an elevated H3Cit level of septic patients, which is far more that of trauma patients (87). The same article confirmed the utility of histones in determining disease progression of sepsis and suggested that H3Cit might serve as an indicator for antibiotics treatment (87).…”

Quantification of citrullinated histones: Development of an improved assay to reliably quantify nucleosomal H3Cit in human plasma

“…Hypercitrullination weakens the histone interaction with DNA, thus unfolding the tightly packed chromatin 10 (Figure 1B) and contributing to NET formation (Figure 1C). H3Cit is therefore considered a useful marker of NET formation 23‐34 …”