Neutrophil CD11b Expression Research Articles

Glutamine attenuates lipopolysaccharide-induced acute lung injury

Objectives It has been reported that glutamine (GLN) can attenuate acute lung injury after sepsis. GLN is also thought to be a precursor of glutathione (GSH) synthesis. Using the GSH synthesis blocker, L-buthionine-(S,R)-sulfoximine (BSO), we investigated the role of GSH synthesis in the protective effect of GLN on acute lung injury. Methods In this study, we used an acute lung injury model induced by intratracheal injection of lipopolysaccharide (1 mg · mL −1 · kg −1). GLN (0.75 g/kg, intravenous) and BSO (2 mmol/kg, intraperitoneal) were administrated simultaneously. At 2 and 18 h after the injections, the rats were sacrificed by right ventricular puncture and bronchoalveolar lavage was done. The lower right lung was excised for histologic examination. Total protein concentration and total cell and neutrophil counts in the bronchoalveolar lavage fluid were determined. CD11b expression in the blood was determined by flow cytometry. We also analyzed myeloperoxidase activity, and GSH and interleukin-8 levels in lung tissues. Results GLN supplementation reduced the total protein concentration and total cell and neutrophils counts in bronchoalveolar lavage fluid after lipopolysaccharide challenge. GLN enhanced GSH synthesis and attenuated interleukin-8 release and myeloperoxidase activity in lung tissues. GLN also decreased CD11b expression in blood neutrophils and prevented lung histologic changes. BSO abolished the effects of GLN and attenuated its protection on acute lung injury. Conclusion These results indicate that GLN could prevent neutrophil recruitment and infiltration, protect the alveolar barrier, and attenuate inflammatory injury during sepsis. This effect may be related to enhanced GSH synthesis.

Hepatic Neutrophil Activation During Reperfusion May Not Contribute to Initial Graft Function After Short Cold Ischemia in Human Liver Transplantation

Background Experimental models of hepatic ischemia/reperfusion injury have implicated a pathophysiologic role for neutrophils in subsequent hepatocellular damage. In human liver transplantation, however, the effect of reperfusion-induced neutrophil activation on initial graft function is not clear. Methods In 38 patients undergoing liver transplantation, neutrophil CD11b and L-selectin expression, neutrophil count, and plasma lactoferrin levels were measured. To assess changes within the graft during initial reperfusion, samples of blood entering and leaving the graft were obtained simultaneously, and transhepatic ratio calculated (hepatic vein/portal vein; 1 denotes no change, <1 a decrease, and >1 an increase across the liver). Graft steatosis, postoperative liver function, and outcome were recorded. Associations between neutrophil activation markers and outcome measures were evaluated. Results Substantial hepatic neutrophil activation occurred during initial reperfusion, demonstrated by concomitant L-selectin shedding and CD11b upregulation (transhepatic ratios 0.9 [0.7–1.0]; 1.4 [0.9–1.9]; both P < .001; portal vs hepatic vein]. Simultaneously, hepatic neutrophil sequestration and lactoferrin release occurred (0.3 [0.2–0.5]; 1.7 [1.3–3.4]; both P < .001). Neither cold ischemic time (CIT; median 5 hours 36 minutes) nor hepatic neutrophil activation during reperfusion predicted early graft function, nor was there any association between CIT and neutrophil activation. Conclusions Despite short CIT, extensive graft neutrophil activation and sequestration occurred. This, however, was not associated with impaired early graft function, suggesting short CIT may protect against severe neutrophil-mediated injury.

Anti‐inflammatory effects of dimemorfan on inflammatory cells and LPS‐induced endotoxin shock in mice

Dimemorfan (a sigma1 receptor agonist) showed neuroprotective properties in animal models of inflammation-mediated neurodegenerative conditions, but its effects on inflammatory cells and systemic inflammation remain unclear. The effects of dimemorfan on phorbol-12-myristate-13-acetate (PMA)- and N-formyl-methionyl-leucyl-phenylalanine (fMLP)- induced neutrophils and lipopolysaccharide (LPS)-activated microglial cells, as well as LPS-induced endotoxin shock in mice were elucidated. Dimemorfan decreased PMA- and fMLP-induced production of reactive oxygen species (ROS) and CD11b expression in neutrophils, through mechanisms independent of sigma1 receptors, possibly by blocking ROS production and G-protein-mediated intracellular calcium increase. Dimemorfan also inhibited LPS-induced ROS and nitric oxide (NO) production, as well as that of monocyte chemoattractant protein-1 and tumour necrosis factor-alpha (TNF-alpha), by inhibition of NADPH oxidase (NOX) activity and suppression of iNOS up-regulation through interfering with nuclear factor kappa-B (NF-kappaB) signalling in microglial cells. Treatment in vivo with dimemorfan (1 and 5 mg kg(-1), i.p., at three successive times after LPS) decreased plasma TNF-alpha, and neutrophil infiltration and oxidative stress in the lung and liver. Our results suggest that dimemorfan acts via sigma1 receptor-independent mechanisms to modulate intracellular calcium increase, NOX activity, and NF-kappaB signalling, resulting in inhibition of iNOS expression and NO production, and production of pro-inflammatory cytokines. These effects may contribute its anti-inflammatory action and protective effects against endotoxin shock in mice.

Contribution of circulating platelet and leukocyte activation to primary pulmonary hypertension in rats

To evaluate the contribution of platelet and leukocyte activation in pathogenesis primary pulmonary hypertension (PPH). Pulmonary hypertension was induced by subcutaneous injection of 2% monocrotaline (MCT) in male Prague-Dawley (SD) rats. Blood samples were collected at the third week after MCT injection, and flow cytometry was used to determine the fibrinogen-binding platelet, CD11b expression on leukocyte and platelet-leukocyte aggregation. Three weeks after MCT injection, rats exhibited higher right ventricular systolic pressure (RVSP) and mean pulmonary artery pressure(mPAP), as compared with controls. MCT induced vascular remodeling characterized by vascular medial wall thickening in pulmonary muscular arteries. The ratio of platelets fibrinogen binding was increased in rats 3 weeks after MCT injection than that of control group[(4.08 +/-1.59)% compared with (1.45 +/- 0.61)%, P<0.01]. CD11b expression in monocytes and neutrophils, but not in lymphocytes was increased significantly 3 weeks after MCT injection (P <0.01). Platelet-neutrophil aggregations increased in MCT injected rats as compared with controls (P <0.01). Rats of PPH model demonstrate enhanced circulating platelet and leukocyte activation, which may contribute to the pathogenesis of PPH.

LRG-accelerated differentiation defines unique G-CSFR signaling pathways downstream of PU.1 and C/EBPε that modulate neutrophil activation

Expression of leucine-rich alpha2 glycoprotein (LRG), a member of the leucine-rich repeat family of proteins, was recently shown to be up-regulated during neutrophil differentiation. Its precise role in granulopoiesis, however, remains unknown. In this paper, we show that the transcription factors PU.1 and C/EBPepsilon that regulate the expression of multiple myeloid-specific genes also bind to the LRG promoter. We also demonstrate that LRG localizes to the same cytoplasmic compartment as myeloperoxidase and that G-CSF treatment of the 32Dcl3 myeloid cell line induces nuclear translocation of LRG. Stable transfection of LRG into 32Dcl3 cells resulted in accelerated, G-CSF-mediated neutrophil differentiation and induction of CD11b expression. In contrast, constitutive expression of LRG in 32Dwt18 cells, expressing a chimeric erythropoietin (Epo)/G-CSFR consisting of the EpoR extracellular domain fused to the G-CSFR transmembrane and cytoplasmic domains, failed to induce accelerated neutrophil differentiation and CD11b expression in response to Epo stimulation. LRG-mediated accelerated differentiation and CD11b expression were found to correlate with an increased level of phospho-Stat3 but not with PU.1 or p27(kip1) levels. Hence, similar to other genes involved in neutrophil differentiation, the expression of LRG also appears to be regulated by PU.1 and C/EBPepsilon. Collectively, these findings suggest a role for LRG in modulating neutrophil differentiation and expression of CD11b via nonredundant G-CSFR signals.

Complement inhibition reduces injury in the type 2 diabetic heart following ischemia and reperfusion

Chronic inflammation exacerbates the cardiovascular complications of diabetes. Complement activation plays an important role in the inflammatory response and is known to be involved in ischemia-reperfusion (I/R) injury in the nondiabetic heart. The purpose of this study was to determine if increased complement deposition explains, in part, the increased severity of neutrophil-mediated I/R injury in the type 2 diabetic heart. Nondiabetic Zucker lean control (ZLC) and Zucker diabetic fatty (ZDF) rats underwent 30 min of coronary artery occlusion followed by 120 min of reperfusion. Another group of ZDF rats was treated with the complement inhibitor FUT-175 before reperfusion. Left ventricular (LV) tissue samples were stained for complement deposition and neutrophil accumulation following reperfusion. We found significantly more complement deposition in the ZDF LV compared with the ZLC (P < 0.05), and complement deposition was associated with significantly greater neutrophil accumulation. In whole blood samples taken preischemia and at 120 min reperfusion, neutrophils exhibited significantly more CD11b expression in the ZDF group compared with the ZLC group (P < 0.05). Furthermore, intracellular adhesion molecule (ICAM)-1 expression following I/R was increased significantly in ZDF hearts compared with ZLC hearts (P < 0.001). These results indicate that, in the ZDF heart, increased ICAM-1 and polymorphonuclear neutrophil (PMN) CD11b expression play a role in increasing PMN accumulation following I/R. The infarct size of the ZDF was significantly greater than ZLC (P < 0.05), and treatment with FUT-175 significantly decreased infarct size, complement deposition, and PMN accumulation in the diabetic heart. These findings indicate an exacerbated inflammatory response in the type 2 diabetic heart that contributes to the increased tissue injury observed following ischemia and reperfusion.

Mesenteric Lymph Duct Ligation Attenuates Lung Injury and Neutrophil Activation After Intraperitoneal Injection of Endotoxin in Rats

The release of injurious factors into the mesenteric lymph from the ischemic intestine has been shown to contribute to lung injury and systemic inflammation after shock and trauma. Since endotoxemia is also associated with gut injury, we tested the hypothesis that mesenteric lymph contributes to the lung injury seen in endotoxemia and that the ligation of the mesenteric lymph duct will attenuate this injury. To test this hypothesis, male Sprague-Dawley rats were given intraperitoneal injections (i.p.) of lipopolysaccharide (LPS) (10 mg/kg) with or without mesenteric lymph duct ligation (LDL). At 6 hours after injection of LPS, gut and lung injury, lung permeability, and neutrophil CD11b expression were measured. Lung permeability was quantified by calculating the percentage of Evan's Blue dye and the total protein concentration in the bronchoalveolar lavage fluid (BALF) when compared with the plasma and gut and lung injury were assessed morphologically. LDL attenuated LPS- induced lung injury, lung permeability, and rat PMN CD11b expression but not villous injury. The magnitude of lung permeability as measured by Evan's Blue was approximately twofold greater in the LPS rats when compared with the LPS-treated rats with LDL. The expression of CD11b was greater in the LPS rats when compared with LPS rats with LDL or to sham controls (582 +/- 106 vs. 364 +/- 29 vs. 224 +/- 12 mean fluorescence intensity p < 0.001). Based on the attenuation of lung injury and CD11b expression, these results suggest that LPS-induced lung injury and neutrophil activation is partially mediated through the release of factors from the injured gut into mesenteric lymph.

Mannitol Upregulates Monocyte HLA-DR, Monocyte and Neutrophil CD11b, and Inhibits Neutrophil Apoptosis

D-Mannitol is a substance widely used for both clinical applications as a strong diuretic and in basic research as a purportedly inert osmotic control substance. However, recent experiments have shown that mannitol is able to decrease neutrophil apoptosis in vitro by more than 25%. The aim of the current study was to assess mannitol's effects on two immune cell activation markers; CD11b on neutrophils and monocytes, and HLA-DR on monocytes. Exposure of diluted whole blood (1:10 in RPMI 1640) to increasing concentrations of mannitol for 24 h was associated with a significant increase in both monocyte and neutrophil CD11b expression in non-lipopolysaccharide (LPS)-stimulated samples. Monocyte HLA-DR, but not neutrophil HLA-DR, was significantly higher in the presence of 16.5 mM/l mannitol, whereas isoosmolar NaCl had no effect. Levels of IL-6 and TNF-alpha were not affected by mannitol in our model. All reagents were tested negative for endotoxin contamination. Together, these data indicate that mannitol may directly interact with neutrophils and monocytes. Further systematic evaluation is indicated to define the precise immunomodulating actions of mannitol, and to assess these effects in patients receiving such therapy.

Increased platelet, leukocyte, and coagulation activation in primary myelofibrosis

Platelet and leukocyte activation has been demonstrated in polycythemia vera (PV) and essential thrombocythemia (ET), but such information is limited in primary myelofibrosis (PMF). Platelet, leukocyte, endothelial, and coagulation activation status was assessed in 26 PMF patients and compared with data from 22 age- and sex-matched healthy individuals. Study included flow cytometry assessment of platelet P-selectin expression [at baseline and after adenosine diphosphate (ADP), thrombin and arachidonic acid stimulation], platelet-neutrophil and platelet-monocyte complexes, and CD11b expression in neutrophils and monocytes. Additionally, soluble P-selectin, sCD40L, tissue factor, thrombomodulin, prothrombin fragment 1 + 2 (F1 + 2), and D-dimer were measured by enzyme-linked immunosorbent assays. The above parameters were correlated with the patients' clinical data and presence of the JAK2 V617F mutation. Compared with controls, PMF patients had increased baseline platelet activation, as shown by significantly higher levels of soluble and platelet P-selectin expression, and also higher percentages of platelet-monocyte complexes. Neutrophil and monocyte CD11b expression was significantly higher in patients with the JAK2 mutation than in those with wild-type allele or the controls. Endothelial and coagulation activation, as demonstrated by increased plasma levels of thrombomodulin and F1 + 2, was also found in PMF, with patients with the JAK2 mutation showing significantly higher values of F1 + 2 than those with wild-type allele. In conclusion, PMF patients have platelet, leukocyte, endothelial, and coagulation activation similar to that in PV and ET. CD11b overexpression and F1 + 2 are correlated with the presence of the JAK2 mutation.

Proinflammatory and vasodilator effects of nociceptin/orphanin FQ in the rat mesenteric microcirculation are mediated by histamine

Nociceptin/orphanin FQ (N/OFQ) is the endogenous ligand for the N/OFQ peptide receptor (NOP). N/OFQ causes hypotension and vasodilation, and we aimed to determine the role of histamine in inflammatory microvascular responses to N/OFQ. Male Wistar rats (220-300 g, n = 72) were anesthetized with thiopental (30 mg/kg bolus, 40-90 mg x kg(-1) x h(-1) iv), and the mesentery was prepared for fluorescent intravital microscopy using fluorescein isothiocyanate-conjugated BSA (FITC-BSA, 0.25 ml/100 g iv) or 1 microm fluorescently labeled microspheres. N/OFQ (0.6-60 nmol/kg iv) caused hypotension (SAP, baseline: 154 +/- 11 mmHg, 15 nmol/kg N/OFQ: 112 +/- 10 mmHg, P = 0.009), vasodilation (venules: 23.9 +/- 1.2 microm, 26.7 +/- 1.2 microm, P = 0.006), macromolecular leak (interstitial gray level FITC-BSA: 103.7 +/- 3.4, 123.5 +/- 11.8, P = 0.009), and leukocyte adhesion (2.0 +/- 0.9, 15.2 +/- 0.9/100 microm, P = 0.036). Microsphere velocity also decreased (venules: 1,230 +/- 370 microm/s, P = 0.037), but there were no significant changes in blood flow. Flow cytometry measured a concurrent increase in neutrophil expression of cd11b with N/OFQ vs. controls (Geo mean fluorescence: 4.19 +/- 0.13 vs. 2.06 +/- 0.38, P < 0.05). The NOP antagonist [Nphe(1),Arg(14),Lys(15)]N/OFQ-NH(2) (UFP-101; 60 and 150 nmol/kg iv), H(1) and H(2)antagonists pyrilamine (mepyramine, 1 mg/kg iv) and ranitidine (1 mg/kg iv), and mast cell stabilizer cromolyn (1 mg x kg(-1) x min(-1)) also abolished vasodilation and macromolecular leak to N/OFQ in vivo (P < 0.05), but did not affect hypotension. Isolated mesenteric arteries (approximately 200 microm, n = 25) preconstricted with U-46619 were also mounted on a pressure myograph (60 mmHg), and both intraluminally and extraluminally administered N/OFQ (10(-5) M) caused dilation, inhibited by pyrilamine in the extraluminal but not the intraluminal (control: -6.9 +/- 3.8%; N/OFQ: 32.6 +/- 8.4%; pyrilamine: 31.5 +/- 6.8%, n = 18, P < 0.05) experiments. We conclude that, in vivo, mesenteric microvascular dilation and macromolecular leak occur via N/OFQ-NOP-mediated release of histamine from mast cells. Therefore, N/OFQ-NOP has an important role in microvascular inflammation, and this may be targeted during disease, particularly as we have proven that UFP-101 is an effective antagonist of microvascular responses in vivo.

Inhibition of Platelet Receptors Involved in Neutrophil–Platelet Interaction in Model Cardiopulmonary Bypass

We investigated the interactions between neutrophils, platelets, and artificial surfaces, and whether blocking of relevant receptors on platelets reduced unwanted activation responses in model cardiopulmonary bypass. Isolated neutrophils and platelets resuspended in heparin-anticoagulated plasma were recirculated with and without blocking antibodies to CD62P, CD42b, or junctional adhesion molecule C (JAM-C) in polyvinyl chloride tubing using a roller pump. Platelet adhesion to the tubing was inhibited by anti-CD42b and anti-CD62P, and adhesion of neutrophils by anti-JAM-C. Formation of platelet-neutrophil and platelet aggregates was reduced by anti-CD62P. Anti-JAM-C decreased platelet-neutrophil aggregation at low concentrations and platelet macroaggregates at high concentrations. Anti-CD62P increased neutrophil CD11b expression but not degranulation. Anti-JAM-C substantially increased neutrophil degranulation and slightly increased CD11b expression. Platelet activation increased when CD62P was blocked and decreased with anti-CD42b antibody. High-dose anti-JAM-C reduced platelet activation. In conclusion, inhibiting platelet and neutrophil-platelet interactions had useful effects but no single blocking antibody seemed capable of inducing only beneficial effects.

Can preoperative modelling of individual neutrophil adhesion responses predict renal morbidity?☆

Perioperative upregulation of the neutrophil adhesion molecule CD11b is associated with the development of renal impairment. We hypothesised that individual variation in neutrophil adhesion molecule responses to surgery influences renal outcomes and that this individual variability could be modelled prior to surgery and used to predict high risk patients. The developed model uses preoperative exposure of an individual patient's neutrophils to a fixed inflammatory stimulus and assessment of the basal and stimulated adhesion molecule CD11b expression. Neutrophils were isolated from human volunteers undergoing cardiac surgery with cardiopulmonary bypass support. Basal and stimulated CD11b expression was measured using flow cytometry in preoperative neutrophil samples and compared to postoperative clinical performance. Patients with low levels of preoperative basal neutrophil CD11b expression had the greatest increase in CD11b following phorbol-12-myristate-13-acetate stimulation. This stimulated CD11b response correlated with changes in CD11b expression from preoperative to postoperative sampling. Preoperative basal CD11b expression showed a significant inverse relationship with postoperative creatinine levels. However, preoperative CD11b stimulation was not related to postoperative renal function. In addition preoperative basal CD11b expression correlated with adrenaline requirements and intra-aortic balloon pump usage. In contrast stimulated CD11b expression was significantly related to length of hospital stay and changes in the A-a gradient. Preoperative CD11b expression assessment might enable preoperative identification of patients who will mount an exaggerated and damaging neutrophil response to surgery which contributes to renal injury. Identification of these patients would then allow selective application of immunomodulatory therapies.

The effects of propofol on neutrophil function, lipid peroxidation and inflammatory response during elective coronary artery bypass grafting in patients with impaired ventricular function

Coronary artery bypass grafting (CABG) with cardiopulmonary bypass elicits a potent reperfusion injury and inflammatory response, more intense in patients with impaired myocardial function. Propofol has antioxidant properties which may attenuate such a response. In total, 27 patients with impaired left ventricular function undergoing CABG were randomly allocated to receive either target-controlled infusion propofol (P) or saline (S) immediately before aortic cross-clamp release until 4 h after reperfusion. Troponin-I, Urinary 8-epi PGF-2alpha isoprostane, coronary sinus and systemic malondialdehyde concentrations, Interleukin-6 (IL-6), -8 and -10 concentrations and leucocytes function studies (neutrophil respiratory burst, phagocytosis, CD-11b and CD-18 expression) were measured. Propofol decreased MDA coronary sinus concentration at 1, 3 and 5 min after reperfusion (P<0.01); 60 min after reperfusion a significant difference between the two groups in systemic MDA concentrations was also seen. IL-6 concentration increases were significantly greater in Group S than Group P, 4 h after reperfusion [1118 (1333) pg ml(-1) vs 228 (105) pg ml(-1), P<0.01]. Serum IL-8 concentrations did not increase significantly in either group. Compared with baseline values IL-10 concentrations decreased after reperfusion but the values were higher in the propofol group than in the control group [22 (16) vs 11 (4) pg ml(-1), P<0.05]. No difference in leucocyte function or urinary isoprostane concentrations was demonstrated. Propofol attenuates free-radical-mediated lipid peroxidation and systemic inflammation in patients with impaired myocardial function undergoing CABG.

Study on CD11b expression of neutrophils and lymphocytes in pediatric sepsis

目的 探讨脓毒症患儿中性粒细胞、淋巴细胞CD11b的表达意义.方法 用流式细胞术检测脓毒症(观察组)患儿27例中性粒细胞、淋巴细胞CD11b表达,并与对照组20例和正常组20例比较.结果 在急性期、恢复期,观察组中性粒细胞CD11b[(98.26±1.55)%,(97.74±1.41)%],与对照组[(86.3±6.33)%,(81.48±3.35)%]和正常组[(69.59±9.98)%]比较,P＜0.05.急性期,观察组淋巴细胞CD11b[(15.17±10.2)%],低于对照组[(19.2±7.6)%],P＜0.05;严重脓毒症淋巴细胞CD11b[(6.54±2.52)%]表达下调,低于脓毒症组[(19.45±8.68)%],P＜0.05.结论 中性粒细胞、淋巴细胞CD11b表达在脓毒症的演变过程中起到一定的作用,可作为脓毒症的判断依据,预测疾病的发展。

Leukocyte Filter Enhances Neutrophil Activation during Combined Aortic Valve and Coronary Artery Bypass Surgery

Cardiopulmonary bypass-induced systemic inflammatory reaction involving the expression of neutrophil surface adhesion molecules is the main mechanism leading to myocardial ischemia-reperfusion injury as well as multiorgan dysfunction. Patients undergoing prolonged cardiopulmonary bypass are especially at risk in this regard. The aim of this prospective, randomized study was to evaluate the impact of continuous leukocyte filtration on the perioperative expression of neutrophil adhesion molecules along with the markers of systemic inflammation during combined coronary artery revascularization and aortic valve surgery due to aortic stenosis. Twenty patients scheduled for combined coronary artery revascularization and aortic valve surgery due to aortic stenosis were randomized to undergo cardiopulmonary bypass with or without a leukocyte filter (LeukoGuard LG6). The expression of neutrophil adhesion molecules and proinflammatory cytokine response were measured. The use of the leukocyte filter significantly increased neutrophil CD11b expression (Pg = .003) compared to the control group, which was followed by a faster rise in interleukin-6 levels 5 minutes (median, 125 versus 34 pg/mL) and 2 hours after cardiopulmonary bypass (median, 158 versus 92 pg/mL, Pt x g < .001), respectively. No marked differences in terms of levels of CD11a, CD62L, cardiac troponin-I, or oxyhemodynamics were observed. The observed increased neutrophil activation and enhanced inflammatory response do not support the use of continuous leukofiltration in patients undergoing prolonged cardiopulmonary bypass.

IGA MODULATES NEUTROPHIL INFLAMMATORY POTENTIAL FOLLOWING CHEMOTAXIS

Objective: Respiratory mucosal defense provided by secretory IgA (SIgA) may not only act to prevent colonization and invasive infection by "immune exclusion" but may also modulate the immunoinflammatory response by PMNs and macrophages. We compared PMN activation in different cell populations in response to stimulation by lipopolysaccharide (LPS) or heat-killed bacteria. The relative ability of SIgA or IgG to modulate this response was also studied in-vitro. Methods: Monocytes from healthy volunteers were cocultured with LPS or heat-killed E. coli (HK-EC). Either IgA or IgG was added to subsets and culture supernatants obtained. PMNs were then placed in the apical (Ap) chamber of a 10 well chemotaxis chamber containing cell culture supernatants in the basal (Ba) chamber. This resulted in two PMN populations, an apical or non-migrated population and a basal or migrated population, based on chemotactic activities. Neutrophil CD11b expression, superoxide anion production (O2−) and elastase release were determined in both groups. Results: Mean ± SD (n = 4 each)TableResults were similar in experiments conducted with HK-EC. Conclusion: PMN migration was associated with enhanced inflammatory potential. This effect was abrogated by IgA but not IgG. SIgA is important in modulating immunoinflammatory response to LPS and other stimuli. Maintenance of normal IgA levels may limit the severity of acute lung injury and adult respiratory distress syndrome in the clinical setting.

Onset of Mechanical Ventilation Is Associated With Rapid Activation of Circulating Phagocytes in Preterm Infants

In preterm infants with respiratory distress syndrome (RDS), circulating neutrophils are activated. Kinetics and effects of surfactant therapy on this activation are unknown. Therefore, we studied activation of circulating neutrophils and monocytes in newborn preterm infants with and without RDS. Preterm infants with RDS who were mechanically ventilated and received surfactant ("ventilated infants": n = 38; mean gestational age +/- SD: 28.3 +/- 2.2 weeks; mean birth weight +/- SD: 1086 +/- 353 g) and preterm infants who received nasal continuous positive airway pressure (n = 8) or no ventilatory support (n = 17) ("control infants": mean gestational age +/- SD: 32.1 +/- 1.2 weeks; mean birth weight +/- SD: 1787 +/- 457 g) were recruited. Blood samples were taken from ventilated infants at birth, before surfactant treatment, at 1 and 2 hours after surfactant, and at 12 to 24 hours of age. Blood samples were taken from control infants at birth, at 2 to 6 hours, and at 12 to 24 hours of age. Phagocyte CD11b expression was analyzed by flow cytometry. In ventilated infants, phagocyte CD11b expression increased from birth to the first postnatal samples. It increased further by 12 to 24 hours of age. Control infants with or without nasal continuous positive airway pressure showed no significant increase after birth. At 12 to 24 hours of age, phagocyte CD11b expression was higher in ventilated infants than in control infants. In ventilated infants, neutrophil CD11b expression at 1 and 2 hours after surfactant correlated positively with gestational age. In preterm infants with RDS, significant activation of circulating phagocytes occurs within 1 to 3 hours of the onset of mechanical ventilation, independent of surfactant administration, which indicates that mechanical ventilation may be the inducer of this systemic inflammatory response.

Graft protein C entrapment is associated with reduced phagocyte activation during reperfusion in human liver transplantation

To explore the potential anti-inflammatory role of protein C pathway in ischemia-reperfusion injury during liver transplantation. Prospective, observational clinical study. Tertiary teaching hospital. Fifty adult patients undergoing liver transplantation for acute liver failure or chronic liver disease. To assess changes occurring across the transplanted liver, samples of blood entering and leaving the graft were obtained simultaneously from portal and hepatic veins. Plasma protein C and activated protein C levels, neutrophil and monocyte CD11b and L-selectin expression, and leukocyte differential counts were measured. Postoperative liver function and outcome of transplantation were recorded. During reperfusion, protein C became entrapped within the graft (portal vein 49% [20-96%]; graft caval effluent 25% [12-76%], p < .001), without concomitant activated protein C outflow from the graft. Simultaneously, marked neutrophil and monocyte activation occurred within the graft. Enhanced hepatic protein C entrapment was associated with reduced neutrophil and monocyte activation (R = .377, p = .011; R = .389, p = .008, respectively) during reperfusion. Protein C entrapment occurs immediately during reperfusion in the graft without concomitant activated protein C release, suggesting a shortage of activated protein C in the reperfused graft. The ongoing inflammatory response during reperfusion may lead to protein C and activated protein C utilization within the graft. Indeed, hepatic protein C entrapment is associated with reduced hepatic phagocyte activation, suggesting a regulatory role for protein C pathway in hepatic reperfusion in human liver transplantation.

Amiloride combined with small-volume resuscitation with hypertonic saline is superior in ameliorating trauma-hemorrhagic shock-induced lung injury in rats to the administration of either agent alone

Recognition of the limitations of standard crystalloid resuscitation has led to exploration for alternative resuscitation strategies that might better prevent the development of trauma-hemorrhage-induced organ dysfunction and systemic inflammation. Thus, the goal of this study was to compare the effects of two resuscitation strategies alone and in combination with that of standard resuscitation with Ringer's lactate. These two strategies were intravenous injection of amiloride, an inhibitor of Na/H exchange and epithelial Na channels, and resuscitation with hypertonic saline. Prospective animal study with concurrent control. Small animal laboratory. Adult male Sprague-Dawley rats. Rats injected with amiloride or its vehicle were subjected to trauma-hemorrhagic shock (T/HS) or trauma sham-shock (T/SS) and resuscitated with Ringer's lactate or hypertonic saline. The T/HS model consisted of a laparotomy plus 90 mins of shock (mean arterial pressure 30 mm Hg). Three hours after the end of the shock or sham-shock period, lung permeability, lung histology, pulmonary neutrophil sequestration, neutrophil CD11b expression, gut injury, and red blood cell rigidification were assessed. Both amiloride and hypertonic saline reduced T/HS-induced pulmonary permeability and neutrophil sequestration, and coadministration of these two agents was more efficacious than administration of the individual agents. In contrast, whereas gut injury was attenuated by both amiloride and hypertonic saline, combined administration of amiloride and hypertonic saline failed to further protect the gut. Additionally, hypertonic saline reduced both neutrophil CD11b expression and red blood cell rigidification, whereas amiloride was without effect. Combined administration of amiloride and small-volume resuscitation with hypertonic saline may be a strategy worthy of further evaluation in the therapy of shock-induced distant organ injury.

Activated Protein C Reduces Graft Neutrophil Activation in Clinical Renal Transplantation

We studied the role of endogenous activated protein C (APC), the major physiological anti-coagulant with concomitant anti-inflammatory properties, on ischemia/reperfusion (I/R) in 45 patients participating in a larger trial comparing three immunosuppressive protocols in cadaveric renal transplantation: perioperative anti-thymocyte globulin (ATG, Fresenius AG, Bad Homburg, Germany), perioperative basiliximab and conventional triple therapy. Blood samples for assessing plasma APC, protein C, and lactoferrin concentrations, neutrophil CD11b and L-selectin expressions and blood leukocyte differential counts were obtained preoperatively and before reperfusion from central venous cannula, complemented with simultaneous samples from iliac artery and graft vein for calculation of transrenal differences (Delta) of study parameters at 1 and 5 min after reperfusion. Unlike basiliximab or conventional therapy groups, ATG infusion induced a substantial increase in plasma APC concentration (119 [88-144]% before infusion vs. 232 [85-1246]% after infusion, p<0.001), resulting in renal graft sequestration of APC at 1 min after reperfusion (Delta=-72 [-567 to 12]%, p<0.001). Graft APC consumption was associated with transrenal reduction of neutrophil activation markers (L-selectin r=0.7, p=0.01; lactoferrin r=-0.6, p=0.02; CD11b r=-0.8, p=0.001), and with both warm (r=0.6, p=0.01) and cold ischemia time (r=0.6, p=0.02) and donor age (r=0.6, p=0.01). These findings suggest that APC has an anti-inflammatory role in I/R injury in clinical renal transplantation.