Plasmas From Patients With Burn Injury Induce Endotheliopathy Through Different Pathways

Introduction

The contribution of endothelial injury to the pathogenesis of burn shock is not well characterized. This work investigates potential mechanisms underlying dysregulation of endothelial barrier function by burn patient plasmas.

Methods

Plasma was collected from burn-injured patients (n = 8) within 4 h of admission. Demographic and injury characteristics were collected and markers of injury severity including international normalized ratio, activated partial thromboplastin time, and levels of syndecan-1 and interleukin (IL)-6, IL-1B, IL-10, Il-12p70, and tumor necrosis factor-α measured. Human umbilical vein endothelial cell monolayers (HUVEC-m) exposed to either burn patient plasma or multidonor plasma (HHP) were assessed for permeability (40 kDa fluorescein isothiocyanate (FITC)-Dextran diffusion), intercellular gap area (F-actin staining) and incidence of apoptosis (TUNEL assay). Post plasma exposure, RNA was isolated and used in polymerase chain reaction (PCR) arrays targeting genes relevant to cytoskeletal structure or apoptosis. Differences between HHP and burn plasma-treated HUVEC-m were analyzed.

Results

Five plasmas promoted significant increases in HUVEC-m permeability. When plasmas were grouped based on their capacity to increase permeability, no differences in age, %total body surface area, gender, hospital mortality, international normalized ratio, activated partial thromboplastin time, or cytokine concentration were observed; however, significantly higher syndecan-1 levels were seen in the plasmas inducing increased permeability. Increases in intercellular gap area and apoptosis and relevant gene expression were observed after exposure to patient plasmas but none of these metrics correlated completely with the pattern or magnitude of the changes in permeability.

Conclusions

Burn patient plasmas variably disrupt HUVEC-m homeostasis, differentially inducing changes in permeability, intercellular gap area, and apoptosis. Neither increases in intercellular gap size nor apoptosis appear sufficient to explain the pattern of changes in permeability.