Circulating Cell-Free Nuclear DNA Is Associated With Fibrinolytic Shutdown After Injury
Kristen T Carter1, Matthew E Kutcher1, Robert R Rieske2, Viktor M Pastukh2, Mark N Gillespie2, Jon D Simmons2
1Department of Surgery, University of Mississippi Medical Center, Jackson, MS
2Department of Surgery, University of South Alabama Medical Center, Mobile, AL
Circulating cell free nuclear DNA (cfDNA) is an emerging link between the innate immune, coagulation, and inflammation systems. The presence of circulating cfDNA has been shown to augment thrombin generation and platelet activation, but its effects on fibrinolysis are less clear. Critically injured patients meeting highest-level trauma activation criteria were prospectively enrolled under waiver of consent, and blood sampled within 6h of arrival. Citrated kaolin thromboelastography (TEG) was used to divide fibrinolysis into shutdown, normal, and hyperfibrinolytic ranges based on Lysis Index at 30min (LY30). Real-time quantitative PCR for the 18s nuclear DNA sequence was performed and correlated with fluorometric cfDNA quantitation. In 35 injured patients, circulating 18s cfDNA levels were elevated 2.8-fold compared to 21 healthy volunteers (p<0.01), and were 4.2-fold higher in blunt compared to penetrating injury (p=0.02). On arrival, 29% of injured patients demonstrated fibrinolytic shutdown, 68% had normal-range fibrinolysis, and 3% had hyperfibrinolysis. Median cfDNA concentration was 5.6ng/mL (interquartile range 0.3 – 11.8) in patients with shutdown, compared to 0.3 (0.1 – 0.6) in those with normal or hyperfibrinolysis (Kruskal-Wallis p=0.029; see figure). When adjusted for age and injury severity, 18s cfDNA level remained a significant predictor of admission fibrinolytic shutdown (odds ratio 1.30, p=0.045, model area under the curve 0.717). Circulating cell free nuclear DNA is a biomarker of injury severity after trauma and is specifically associated with early fibrinolytic shutdown. Inadequate fibrinolysis and resultant microvascular thrombosis may be a potential driver of multiple organ failure after severe injury.