Fox Elizabeth D, Heffernan Daithi S, Cioffi William G, Reichner Jonathan S
Crit Care. 2013 Oct 7;17(5):R226. doi: 10.1186/cc13049.
Sepsis is characterized by systemic immune activation and neutrophil-mediated endothelial barrier integrity compromise, contributing to end-organ dysfunction. Studies evaluating endothelial barrier dysfunction induced by neutrophils from septic patients are lacking, despite its clinical significance. We hypothesized that septic neutrophils would cause characteristic patterns of endothelial barrier dysfunction, distinct from experimental stimulation of normal neutrophils, and that treatment with the immunomodulatory drug β-glucan would attenuate this effect.
Blood was obtained from critically ill septic patients. Patients were either general surgery patients (Primary Sepsis (PS)) or those with sepsis following trauma (Secondary Sepsis (SS)). Those with acute respiratory distress syndrome (ARDS) were identified. Healthy volunteers served as controls. Neutrophils were purified and aliquots were untreated, or treated with fMLP or β-glucan. Endothelial cells were grown to confluence and activated with tissue necrosis factor (TNF)-α . Electric Cell-substrate Impedance Sensing (ECIS) was used to determine monolayer resistance after neutrophils were added. Groups were analyzed by two-way analysis of variance (ANOVA).
Neutrophils from all septic patients, as well as fMLP-normal neutrophils, reduced endothelial barrier integrity to a greater extent than untreated normal neutrophils (normalized resistance of cells from septic patients at 30 mins = 0.90 ± 0.04; at 60 mins = 0.73 ± 0.6 and at 180 mins = 0.56 ± 0.05; p < 0.05 vs normal). Compared to untreated PS neutrophils, fMLP-treated PS neutrophils caused further loss of barrier function at all time points; no additive effect was noted in stimulation of SS neutrophils beyond 30 min. Neutrophils from ARDS patients caused greater loss of barrier integrity than those from non-ARDS patients, despite similarities in age, sex, septic source, and neutrophil count. Neutrophils obtained after resolution of sepsis caused less barrier dysfunction at all time points. β-glucan treatment of septic patients' neutrophils attenuated barrier compromise, rendering the effect similar to that induced by neutrophils obtained once sepsis had resolved.
Neutrophils from septic patients exert dramatic compromise of endothelial barrier integrity. This pattern is mimicked by experimental activation of healthy neutrophils. The effect of septic neutrophils on the endothelium depends upon the initial inflammatory event, correlates with organ dysfunction and resolution of sepsis, and is ameliorated by β-glucan.
脓毒症的特征是全身免疫激活以及中性粒细胞介导的内皮屏障完整性受损，进而导致终末器官功能障碍。尽管内皮屏障功能障碍具有临床意义，但目前缺乏评估脓毒症患者中性粒细胞诱导的内皮屏障功能障碍的研究。我们推测，脓毒症中性粒细胞会导致内皮屏障功能障碍的特征性模式，这与正常中性粒细胞的实验性刺激不同，并且免疫调节药物β-葡聚糖治疗会减弱这种效应。
从危重症脓毒症患者采集血液。患者包括普通外科患者（原发性脓毒症（PS））或创伤后脓毒症患者（继发性脓毒症（SS））。识别出患有急性呼吸窘迫综合征（ARDS）的患者。健康志愿者作为对照。纯化中性粒细胞，将等分试样不进行处理，或用fMLP或β-葡聚糖处理。使内皮细胞生长至汇合，并用肿瘤坏死因子（TNF）-α激活。在加入中性粒细胞后，使用电细胞基质阻抗传感（ECIS）来测定单层电阻。通过双向方差分析（ANOVA）对各组进行分析。
所有脓毒症患者的中性粒细胞以及fMLP处理的正常中性粒细胞，比未处理的正常中性粒细胞更显著地降低了内皮屏障完整性（脓毒症患者细胞在30分钟时的标准化电阻=0.90±0.04；60分钟时=0.73±0.6，180分钟时=0.56±0.05；与正常相比，p<0.05）。与未处理的PS中性粒细胞相比，fMLP处理的PS中性粒细胞在所有时间点均导致屏障功能进一步丧失；在刺激SS中性粒细胞超过30分钟后未观察到叠加效应。ARDS患者的中性粒细胞比非ARDS患者的中性粒细胞导致更大程度的屏障完整性丧失，尽管在年龄、性别、脓毒症来源和中性粒细胞计数方面相似。脓毒症缓解后获得的中性粒细胞在所有时间点导致的屏障功能障碍均较少。用β-葡聚糖处理脓毒症患者的中性粒细胞可减轻屏障受损，使其效应类似于脓毒症缓解后获得的中性粒细胞所诱导的效应。
脓毒症患者的中性粒细胞显著损害内皮屏障完整性。健康中性粒细胞的实验性激活可模拟这种模式。脓毒症中性粒细胞对内皮的影响取决于初始炎症事件，与器官功能障碍和脓毒症的缓解相关，并且可被β-葡聚糖改善。
