Inflammation resolution circuits are uncoupled in acute sepsis and correlate with clinical severity
Bakr Jundi, Do-Hyun Lee, Hyungkook Jeon, Melody G. Duvall, Julie Nijmeh, Raja-Elie E. Abdulnour, Mayra Pinilla-Vera, Rebecca M. Baron, Jongyoon Han, Joel Voldman, Bruce D. Levy
Bakr Jundi, Do-Hyun Lee, Hyungkook Jeon, Melody G. Duvall, Julie Nijmeh, Raja-Elie E. Abdulnour, Mayra Pinilla-Vera, Rebecca M. Baron, Jongyoon Han, Joel Voldman, Bruce D. Levy
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Research Article Inflammation Pulmonology

Inflammation resolution circuits are uncoupled in acute sepsis and correlate with clinical severity

Abstract

Sepsis is a critical illness characterized by dysregulated inflammatory responses lacking counter-regulation. Specialized proresolving mediators are agonists for antiinflammation and for promoting resolution, and they are protective in preclinical sepsis models. Here, in human sepsis, we mapped resolution circuits for the specialized proresolving mediators resolvin D1 and resolvin D2 in peripheral blood neutrophils and monocytes, their regulation of leukocyte activation and function ex vivo, and their relationships to measures of clinical severity. Neutrophils and monocytes were isolated from healthy subjects and patients with sepsis by inertial microfluidics and resolvin D1 and resolvin D2 receptor expression determined by flow cytometry. The impact of these resolvins on leukocyte activation was determined by isodielectric separation and leukocyte function by stimulated phagolysosome formation. Leukocyte proresolving receptor expression was significantly higher in sepsis. In nanomolar concentrations, resolvin D1 and resolvin D2 partially reversed sepsis-induced changes in leukocyte activation and function. Principal component analyses of leukocyte resolvin receptor expression and responses differentiated sepsis from health and were associated with measures of sepsis severity. These findings indicate that resolvin D1 and resolvin D2 signaling for antiinflammation and resolution are uncoupled from leukocyte activation in early sepsis and suggest that indicators of diminished resolution signaling correlate with clinical disease severity.

Authors

Bakr Jundi, Do-Hyun Lee, Hyungkook Jeon, Melody G. Duvall, Julie Nijmeh, Raja-Elie E. Abdulnour, Mayra Pinilla-Vera, Rebecca M. Baron, Jongyoon Han, Joel Voldman, Bruce D. Levy

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Figure 1

Upregulation of SPM receptors DRV1, ALX, and DRV2 on PMN in sepsis.

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Upregulation of SPM receptors DRV1, ALX, and DRV2 on PMN in sepsis. PMN ...
PMN were isolated from 50 μL of peripheral blood using the spiral microfluidics system. (A) Flow cytometry contour plots identifying the various FSC+SSC+CD45+CD66b+PMN subsets based on CD16 surface expression (CD16bright, CD16dim, and CD16–) in isolated blood from healthy and sepsis subjects. (B) Representative flow cytometry histogram plots (upper panels) and violin graphs (lower panels) of CD16bright PMN (FSC+SSC+CD45+CD66b+CD16) surface receptor expression of DRV1, ALX, and DRV2 in control (fluorescence minus 1, light gray), health (dark gray), and sepsis (crimson). Health, n = 4; Sepsis, n = 12–13. (C) Mean fluorescence intensity (MFI) of surface receptor expression of DRV1, ALX, and DRV2 in all PMN subsets in sepsis and health. Health, n = 4; Sepsis, n = 12–13. (D and E) Representative flow cytometry contour plots and frequency of pHrodo+CD16bright PMN in sepsis (crimson) and health (dark gray) after incubation with exogenous RvD1 (100 nM), RvD2 (100 nM), or vehicle (<0.01% v/v EtOH) for 15 minutes at 37°C. Health, n = 4; Sepsis, n = 11. (F) The relative increase of pHrodo+CD16bright PMN with exogenous RvD1 (100 nM) and RvD2 (100 nM) in sepsis calculated as (SPM sepsis – vehicle sepsis)/(vehicle healthy – vehicle sepsis). Sepsis, n = 11. (G) Concentration-response curve of the frequency of pHrodo+CD16bright PMN to varying concentrations of RvD1 (circle, crimson), RvD2 (square, crimson), or vehicle (mean value, dashed gray line). Sepsis, n = 6. (H) Representative flow cytometry contour plots of pHrodo+ CD16dim and CD16– PMN with exogenous RvD1 (100 nM), RvD2 (100 nM), and vehicle (<0.01% v/v EtOH), n = 11. Values are expressed as the mean ± SEM. *P < 0.05 for sepsis versus health by unpaired, 2-tailed t test; **P < 0.05 for vehicle versus RvD1 or RvD2 by paired, 2-tailed t test; ‡P < 0.05 for CD16dim versus CD16bright PMN by paired, 2-tailed t test; ‡‡P < 0.05 CD16– versus CD16bright PMN by paired, 2-tailed t test. H, Health. S, Sepsis.