Spontaneous Neutrophil Migration Patterns during Sepsis after Major Burns

Abstract

Finely tuned to respond quickly to infections, neutrophils have amazing abilities to migrate fast and efficiently towards sites of infection and inflammation. Although neutrophils ability to migrate is perturbed in patients after major burns, no correlations have yet been demonstrated between altered migration and higher rate of infections and sepsis in these patients when compared to healthy individuals. To probe if such correlations exist, we designed microfluidic devices to quantify the neutrophil migration phenotype with high precision. Inside these devices, moving neutrophils are confined in channels smaller than the neutrophils and forced to make directional decisions at bifurcations and around posts. We employed these devices to quantify neutrophil migration across 18 independent parameters in 74 blood samples from 13 patients with major burns and 3 healthy subjects. Blinded, retrospective analysis of clinical data and neutrophil migration parameters revealed that neutrophils isolated from blood samples collected during sepsis migrate spontaneously inside the microfluidic channels. The spontaneous neutrophil migration is a unique phenotype, typical for patients with major burns during sepsis and often observed one or two days before the diagnosis of sepsis is confirmed. The spontaneous neutrophil migration phenotype is rare in patients with major burns in the absence of sepsis, and is not encountered in healthy individuals. Our findings warrant further studies of neutrophils and their utility for early diagnosing and monitoring sepsis in patients after major burns.

Diagnosis of sepsis from a drop of blood by measurement of spontaneous neutrophil motility in a microfluidic assay

“…Thus, their activation during sepsis is likely the cumulative effect of inflammation- and infection-related factors present in the circulation, including many of the putative sepsis biomarkers discussed above. Measuring neutrophil behavior in our previous study revealed changes even after the neutrophils have been isolated from blood 15 . Therefore, we hypothesized that measuring neutrophil motility using whole blood samples might amplify the behavioral changes that we previously observed in isolated neutrophils.…”

“…Neutrophils from septic patients lose the ability to respond appropriately to chemotactic signals 14,15 and have altered antimicrobial activity 16 . Pharmaceutically correcting neutrophil behavior during sepsis has been shown to improve outcomes in animal models 17 , suggesting that neutrophil dysregulation contributes to the severity of sepsis.…”

“…Pharmaceutically correcting neutrophil behavior during sepsis has been shown to improve outcomes in animal models 17 , suggesting that neutrophil dysregulation contributes to the severity of sepsis. Our previous studies identified a sepsis-specific spontaneous motility signature displayed by isolated ex vivo neutrophils in straight microfluidic channels, which allowed prediction of sepsis in patients with major burns with 80% sensitivity and 77% specificity 15 .…”

Kidney and Liver Injuries After Major Burns in Rats Are Prevented by Resolvin D2

“…Overly active neutrophils have been proposed as potential link between the systemic inflammation and secondary organ injury after major burns, supported by genomic (45) and functional measurements (46). Over-activated neutrophils can release their chromatin as NETs (12, 47–51), and results in significant tissue damage (52) (e.g.…”

Mkit: A cell migration assay based on microfluidic device and smartphone

“…Recently, new microfluidic methods have been developed to allow rapid immune cell chemotaxis test directly from a drop of whole blood by incorporating on-chip cell isolation module (Agrawal et al 2008;Hamza and Irimia 2015;Jones et al 2016;Sackmann et al 2012;Sackmann et al 2014b;Wu et al 2016). Several studies have also employed microfluidic cell migration systems for disease orientated applications (Butler et al 2010;Jones et al 2014;Wu et al 2015). These developments provide the general background of microfluidics technology for performing portable cell migration and chemotaxis assays on a smartphone platform.…”