LFA-1 and MAC-1 mediate pulmonary recruitment of neutrophils and tissue damage in abdominal sepsis

Neutrophil-mediated lung damage is an insidious feature in septic patients, although the adhesive mechanisms behind pulmonary recruitment of neutrophils in polymicrobial sepsis remain elusive. The aim of the present study was to define the role of lymphocyte function antigen-1 (LFA-1) and membrane-activated complex 1 (Mac-1) in septic lung injury. Pulmonary edema, bronchoalveolar infiltration of neutrophils, levels of myeloperoxidase, and CXC chemokines were determined after cecal ligation and puncture (CLP). Mice were treated with monoclonal antibodies directed against LFA-1 and Mac-1 before CLP induction. Cecal ligation and puncture induced clear-cut pulmonary damage characterized by edema formation, neutrophil infiltration, and increased levels of CXC chemokines in the lung. Notably, immunoneutralization of LFA-1 or Mac-1 decreased CLP-induced neutrophil recruitment in the bronchoalveolar space by more than 64%. Moreover, functional inhibition of LFA-1 and Mac-1 abolished CLP-induced lung damage and edema. However, formation of CXC chemokines in the lung was intact in mice pretreated with the anti-LFA-1 and anti-Mac-1 antibodies. Our data demonstrate that both LFA-1 and Mac-1 regulate pulmonary infiltration of neutrophils and lung edema associated with abdominal sepsis. Thus, these novel findings suggest that LFA-1 or Mac-1 may serve as targets to protect against lung injury in polymicrobial sepsis.     

CXC chemokine receptor 1 (CXCR1) is expressed mainly by neutrophils in inflamed gut and stomach tissues

CXC chemokine receptor 1 (CXCR1) is one of the important receptors for CXC chemokines with ELR motif, of which interleukin 8 (IL-8; CXCL8) is representative. To identify the cell type(s) of CXCR1-expressing cells in inflamed stomach and gut tissues, we performed immunoperoxidase method using pre-fixed frozen sections. In chronic gastritis associated with Helicobacter pylori infection (7 cases), CXCR1 was positive in neutrophils (polymorphonuclear leucocytes) in the lamina propria near the neck region and those in pit abscess. In ulcerative colitis (6 cases) and Crohn's disease (5 cases), CXCR1 was sporadically expressed by neutrophils in the mucosa, and particularly CXCR1+ neutrophils were abundantly distributed in inflammatory granulation tissue in ulcer base. Double staining confirmed co-localization of CXCR1 and neutrophil elastase. Neither CD3+ T lymphocytes nor CD68+ macrophages were positive for CXCR1. Immunoelectron microscopy confirmed the cell surface localization of CXCR1. Neutrophils protect the host from microbial pathogens. However, they also cause damages to host tissues in chronic inflammation. Therefore, our study underscores the importance of CXCR1 expression in inflammatory processes.     

Interleukin-1-dependent sequential chemokine expression and inflammatory cell infiltration in ischemia-reperfusion injury

OBJECTIVE: Ischemia-reperfusion injury is known to cause organ failure, but the mechanisms of pathogenesis remain unclear. Inflammation is a factor in tissue destruction in ischemia reperfusion injury, and interleukin (IL)-1 is a key promoter of inflammation. DESIGN: Prospective, randomized, and controlled study. SETTING: University laboratory. SUBJECTS: Male mice 6-8 wks of age, in which genes for IL-1alpha and IL-1beta (IL-1alpha/beta deficient) and IL-1 receptor antagonist (IL-1RA deficient) are deleted by homologous recombination, and wild-type controls on a Balb/c background. INTERVENTIONS: In this study, the role of IL-1 on inflammatory cascades, including chemokine expression, inflammatory cell infiltration, and tissue destruction, was investigated in 45 mins of unilateral renal ischemic injury using IL-1alpha/beta-deficient mice and IL-1RA-deficient mice. In addition, the effects of IL-1 on chemokine expression in cultured tubular epithelial cells were investigated. MEASUREMENTS AND MAIN RESULTS: In vivo study revealed that the number of interstitial infiltrated neutrophils and macrophages, which accompanied the increase of the serum levels of keratinocyte-derived chemokine (KC) and macrophage inflammatory protein (MIP)-1alpha, respectively, significantly increased in IL-1RA-deficient mice. The number of interstitial infiltrated neutrophils correlated well with serum levels of KC at 24 hrs after reperfusion, whereas the number of interstitial infiltrated macrophages correlated well with the serum levels of MIP-1alpha and monocyte chemoattractant protein (MCP)-1 at 24 and 48 hrs after reperfusion, respectively. Likewise, in vitro study revealed that stimulation of tubular epithelial cells by IL-1beta and/or H2O2 sequentially induced KC, MIP-1alpha, and MCP-1 in both protein and messenger RNA levels, which is consistent with in vivo results. CONCLUSION: IL-1-dependent inflammatory cascades, followed by inflammatory cell infiltration and subsequent tissue destruction, may affect pathogenesis of renal ischemia-reperfusion injury.     

Prolonged chemokine expression and excessive neutrophil infiltration in the lungs of burn-injured mice exposed to ethanol and pulmonary infection

Pulmonary infections are a major cause of mortality in the critically ill burn patient. Alcohol consumption before burn increases the risk of pulmonary infection. Previously, we have shown an elevated mortality and lung pathology in mice given ethanol before burn and intratracheal infection relative to controls. Here we examine the cellular composition at 24 and 48 h in the circulation and the alveoli of infected mice given alcohol and burn. At 24 h after injury, blood neutrophils obtained from mice exposed to ethanol before burn and infection were 2-fold above those of the experimental controls (P < 0.05). By 48 h, the number of circulating neutrophils decreased and was comparable to levels found in untreated animals. Moreover, at 24 h, bronchoalveolar lavage cells obtained from all treatment groups had similar frequencies and contained 80% neutrophils regardless of treatment. In contrast, the following day, neutrophils were elevated 2-fold only in the alveoli of infected burn animals and 5-fold when ethanol preceded the injury (P < 0.05). These data were confirmed by immunofluorescence microscopy using a neutrophil-specific marker (P < 0.05). Levels of neutrophil chemoattractants, KC and macrophage inflammatory protein 2, and the cytokine, IL-1β, were 2-fold greater in the lungs of infected mice given burn, regardless of ethanol exposure, relative to infected sham injured animals (P < 0.05). Like the number of neutrophils, by the second day after injury, KC and macrophage inflammatory protein 2 remained 5-fold higher in the animals given ethanol, burn, and infection, when compared with other groups (P < 0.05). A similar pattern was seen for pulmonary levels of IL-1β (P < 0.05). Additionally, a reduction in neutrophil apoptosis was observed at the 24-h time point in infected mice exposed to ethanol and burn (P < 0.05). Targeting proinflammatory mediators in mice exposed to ethanol before burn and infection may help alleviate prolonged neutrophil accumulation in the lungs.     

Requirement of interleukin 17 receptor signaling for lung CXC chemokine and granulocyte colony-stimulating factor expression, neutrophil recruitment, and host defense

Bacterial pneumonia is an increasing complication of HIV infection and inversely correlates with the CD4(+) lymphocyte count. Interleukin (IL)-17 is a cytokine produced principally by CD4(+) T cells, which induces granulopoiesis via granulocyte colony-stimulating factor (G-CSF) production and induces CXC chemokines. We hypothesized that IL-17 receptor (IL-17R) signaling is critical for G-CSF and CXC chemokine production and lung host defenses. To test this, we used a model of Klebsiella pneumoniae lung infection in mice genetically deficient in IL-17R or in mice overexpressing a soluble IL-17R. IL-17R-deficient mice were exquisitely sensitive to intranasal K. pneumoniae with 100% mortality after 48 h compared with only 40% mortality in controls. IL-17R knockout (KO) mice displayed a significant delay in neutrophil recruitment into the alveolar space, and had greater dissemination of K. pneumoniae compared with control mice. This defect was associated with a significant reduction in steady-state levels of G-CSF and macrophage inflammatory protein (MIP)-2 mRNA and protein in the lung in response to the K. pneumoniae challenge in IL-17R KO mice. Thus, IL-17R signaling is critical for optimal production of G-CSF and MIP-2 and local control of pulmonary K. pneumoniae infection. These data support impaired IL-17R signaling as a potential mechanism by which deficiency of CD4 lymphocytes predisposes to bacterial pneumonia.     

Increased expression of the interleukin 1 receptor on blood neutrophils of humans with the sepsis syndrome.

Because of the potential importance of interleukin 1 (IL-1) in modulating inflammation and the observations that human blood neutrophils (PMN) express IL-1 receptors (IL-1R) and synthesize IL-1 alpha and IL-1 beta, we studied the IL-1R on blood PMN from a group of patients with the sepsis syndrome. We report a marked enhancement in the sites per cell of IL-1R expressed on sepsis-PMN of 25 consecutively studied patients compared to 20 controls (patient mean = 9,329 +/- 2,212 SE; control mean = 716 +/- 42 SE, respectively). There was no demonstrable difference in the Kd of IL-1R on sepsis-PMN (approximately 1 nM) as determined by saturation curves of 125I-IL-1 alpha binding and the IL-1R on sepsis-PMN had an apparent Mr approximately 68,000, a value like that of normal PMN. Cytofluorographic analysis indicated that the sepsis-PMN phenotype is a single homogeneous population with respect to IL-1R expression. In contrast, expression of the membrane complement receptor CR3 is not increased on sepsis-PMN. Similar increases in expression of IL-1R were not observed in various other inflammatory processes, including acute disseminated inflammation and organ failure not caused by infection, acute infection without organ failure, and immunopathologies such as active systemic lupus erythematosus and rheumatoid arthritis. Enhanced expression of IL-1R was not related simply to the state of myeloid stimulation. Increased expression of IL-1R on normal PMN was induced in vitro by incubating cells with recombinant human granulocyte-macrophage/colony-stimulating factor for 18 h and this response was inhibited by cycloheximide, suggesting the possibility that de novo synthesis of IL-1R might occur in PMN during the sepsis syndrome.     

Subcellular localization and dynamics of Mac-1 (alpha m beta 2) in human neutrophils.

The subcellular localization of Mac-1 was determined in resting and stimulated human neutrophils after disruption by nitrogen cavitation and fractionation on two-layer Percoll density gradients. Light membranes were further separated by high voltage free flow electrophoresis. Mac-1 was determined by an ELISA with monoclonal antibodies that were specific for the alpha-chain (CD11b). In unstimulated neutrophils, 75% of Mac-1 colocalized with specific granules including gelatinase granules, 20% with secretory vesicles and the rest with plasma membranes. Stimulation with nanomolar concentrations of FMLP resulted in the translocation of Mac-1 from secretory vesicles to the plasma membrane, and only minimal translocation from specific granules and gelatinase granules. Stimulation with PMA or Ionomycin resulted in full translocation of Mac-1 from secretory vesicles and gelatinase granules to the plasma membrane, and partial translocation of Mac-1 from specific granules. These findings were corroborated by flow cytometry, which demonstrated a 6-10-fold increase in the surface membrane content of Mac-1 in response to stimulation with FMLP, granulocyte-macrophage colony stimulating factor, IL-8, leukotriene B4, platelet-activating factor, TNF-alpha, and zymosan-activated serum, and a 25-fold increase in response to Ionomycin. Thus, secretory vesicles constitute the most important reservoir of Mac-1 that is incorporated into the plasma membrane during stimulation with inflammatory mediators.     

Cooperative interactions of LFA-1 and Mac-1 with intercellular adhesion molecule-1 in facilitating adherence and transendothelial migration of human neutrophils in vitro.

The adherence of human neutrophils to human umbilical vein endothelial cells (HUVEC) is partially dependent on the CD11/CD18 family of glycoproteins on the neutrophil and ICAM-1 on the HUVEC. The CD18 heterodimer involved in this adherence was evaluated in vitro using subunit-specific monoclonal antibodies (MAbs). The adherence of unstimulated neutrophils to IL-1-stimulated HUVEC was significantly inhibited by anti-CD11a but not CD11b MAbs, while the adherence of fMLP-stimulated neutrophils was significantly inhibited by both anti-CD11a and -CD11b. Anti-CD11a, but not anti-CD11b MAbs, reduced the adherence of unstimulated neutrophils on purified ICAM-1 to the same low level untreated neutrophils exhibited on a control protein, glycophorin. Stimulation with fMLP significantly increased neutrophil attachment to purified ICAM-1, but not to the control protein. Anti-CD11b MAbs reduced this chemotactically augmented adherence to that of unstimulated neutrophils, and in combination with anti-CD11a MAbs reduced adherence to that on the control protein. The results in this report indicate that unstimulated neutrophils exhibit LFA-1-dependent attachment to ICAM-1, and chemotactic stimulation enhances the attachment of human neutrophils to ICAM-1 by a Mac-1-dependent process.     

Altered expression of adhesion molecules (L-selectin and Mac-1) on granulocytes during storage

BACKGROUND: The success of granulocyte transfusion therapy for neutropenic patients with sepsis is dependent on the number and quality of the granulocytes transfused. There is a progressive impairment in granulocyte function during storage. STUDY DESIGN AND METHODS: The effect of 1 to 2, 4, 24, and 48 hours' storage on receptor expression associated with granulocyte function has been analyzed. RESULTS: After 24 hours' storage, significant changes were found in the expression of receptors associated with adhesion to the endothelium: a decrease in L- selectin expression (p < 0.01) and an increase in Mac-1 expression (p < 0.01). Receptors (CR1 and FcRIII), associated with adhesion to target, were either increased (CR1) or unaltered (FcRIII). The capacity to produce a reactive oxygen metabolite (hydrogen peroxide) remained essentially unchanged after 48 hours' storage. The ability of N-formyl- methionyl-leucyl-phenyl alanine to mobilize Mac-1 and CR1 was reduced after 48 hours' storage. CONCLUSION: Since the regulation of adhesion molecules is important for the recruitment of granulocytes into an inflammatory site, the observed in vitro changes in L-selectin and Mac- 1 expression during storage may be of importance for the quality of granulocyte concentrates.     

Tolerance to endotoxin-induced expression of the interleukin-1 beta gene in blood neutrophils of humans with the sepsis syndrome.

The induction of genes of host cells stimulated by microbial products such as endotoxin and the tolerance of cells to endotoxin excitation play critical roles in the pathogenesis of microbial-induced acute disseminated inflammation with multiorgan failure (the sepsis syndrome). One gene that is induced in phagocytic cells by endotoxin and that appears to play an essential role in the pathogenesis of the sepsis syndrome is IL-1 beta. We report here that blood neutrophils (PMN) of patients with the sepsis syndrome (sepsis PMN) are consistently tolerant to endotoxin-induced expression of the IL-1 beta gene, as determined by decreased synthesis of the IL-1 beta protein and reductions in IL-1 beta mRNA. This down-regulation of the IL-1 beta gene in sepsis PMN occurs concomitant with an upregulation in the constitutive expression of the type 2 IL-1 receptor (IL-1R2). These phenotypic changes do not persist in PMN of patients recovering from the sepsis syndrome. Tolerance has stimulus and response specificity since sepsis PMN tolerant to endotoxin can respond normally to Staphylococcus aureus stimulation of IL-1 beta production and they normally secrete elastase. Uninfected patients with severe trauma or shock from causes are not tolerant to endotoxin and tolerance is not limited to patients infected with Gram-negative bacteria. The mechanism responsible for tolerance involves pretranslational events and is not due to loss of the CD14 surface protein, a receptor required for endotoxin induction of IL-1 beta in PMN. The physiological significance of the tolerance to endotoxin and increased expression of IL-1R2 on sepsis PMN is unknown, but may represent an attempt by the host to protect itself from the deleterious effects of disseminated inflammation.     

Inflammation and thrombosis: roles of neutrophils,platelets and endothelial cells and their interactions in thrombus formation during sepsis

Summary

The inflammatory response and the activation of coagulation are two important responses in a host's defense against infection. These mechanisms do not work independently, but cooperate in a complex and synchronous manner. Recent research has also shed light on the critical role of thrombus formation, which prevents the dissemination of microorganisms. The cellular components of blood vessels, i.e. leukocytes, platelets, erythrocytes, and vascular endothelial cells, play significant roles in the development of thrombi in combination with activation of the coagulation system. In addition to the cellular components, alarmins such as histones and high‐mobility group box 1, microparticles and secreted granule proteins are all important for clot formation. In this summary, we review the pathophysiology of sepsis‐induced coagulopathy and the role of cellular components and critical factors released from damaged cells. In addition, we review important therapeutic approaches that have been developed, are under investigation and are currently available in certain countries, including antithrombin, recombinant thrombomodulin, anti‐Toll‐like receptor 4 therapy, anti‐damage associated molecular pattern therapy, and hemoadsorption with a polymyxin B‐immobilized fiber column.

     

Thermal injury-induced peroxynitrite production and pulmonary inducible nitric oxide synthase expression depend on JNK/AP-1 signaling

OBJECTIVE: To determine whether burn-induced peroxynitrite production and expression of lung inducible nitric oxide synthase (iNOS), intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, CXCR2, macrophage inflammatory protein (MIP)-2, and neutrophil chemokine (KC) are mediated by the c-Jun NH2-terminal kinase (JNK). DESIGN: Prospective, experimental study. SETTING: Research laboratory at a university hospital. SUBJECTS: Thermal injury models in the mice. INTERVENTIONS: In experiment 1, specific pathogen-free C57/BL6 mice were subjected to 30% total body surface area third-degree burn over shaved back. At 0 hr, 2 hrs, 4 hrs, and 6 hrs after burn, lung tissues of those mice were harvested for JNK activity assay, AP-1 DNA-binding activity, and pJNK immunohistochemistry. In experiment 2, a specific JNK inhibitor, SP600125, was given (30 mg/kg intraperitoneally) to mice immediately postburn to suppress the JNK activity. At 8 hrs after burn, blood was assayed for the peroxynitrite-mediated dihydrorhodamine (DHR) 123 oxidation. Lung tissues were harvested for myeloperoxidase (MPO) determination, ICAM-1, VCAM-1, CXCR2, KC, MIP-2, interleukin-1beta, and interleukin-6 messenger RNA expression; iNOS immunohistochemical staining; and histologic studies. Pulmonary microvascular dysfunction was quantified by measuring the extravasations of Evans blue dye. MEASUREMENTS AND MAIN RESULTS: The JNK activity and AP-1 DNA-binding activity of lung tissue significantly increased to a peak at 2 hrs and 4 hrs, respectively, after thermal injury. Immunohistochemical study demonstrated that the increase of the pJNK was mostly from the bronchiole epithelial cells. This increase of MPO activity in lung, blood DHR 123 oxidation level, and lung permeability increased six-fold, nine-fold, and four-fold after burn. SP600125 administration obliterated the thermal injury-induced JNK activity, AP-1 DNA-binding activity, and iNOS expression in lung tissue. SP600125 treatment also significantly decreased MPO activity, blood DHR 123 oxidation, and lung permeability by 54%, 8%, and 47%, respectively, and markedly decreased the thermal injury-induced perivascular and interstitial inflammatory cell infiltration and septum edema. Furthermore, SP600125 abolished thermal injury-induced ICAM-1, VCAM-1, CXCR2, MIP-2, and KC but not interleukin-1beta and interleukin-6 messenger RNA levels of lung tissues. CONCLUSIONS: Thermal injury induces lung tissue JNK activation and AP-1 DNA-binding activity mainly from airway epithelial cells. Thermal injury-induced peroxynitrite production and lung iNOS, ICAM-1, and VCAM-1 expression are mediated by the JNK signaling. JNK inhibition decreases thermal injury-induced lung neutrophil infiltration and subsequently pulmonary hyperpermeability.     

脓毒症小鼠多器官髓样细胞触发受体1基因的表达及其意义

目的 探讨脓毒症时小鼠肺、肝、肾及小肠组织髓样细胞触发受体1(TREM1)表达的改变及其意义.方法 雄性昆明小鼠60只,随机分为对照组(10只)、假手术组(10只)、盲肠结扎穿孔(CLP)组(40只), CLP法制备脓毒症模型,CLP后6、12、24和48 h处死动物分别留取肺、肝、肾及空肠组织,采用半定量逆转录多聚酶链反应(RT-PCR)法检测TREM1、TNF-α mRNA 的表达.结果 CLP组6、12、24和48 h肺、肝、肾组织TREM1及TNF-α mRNA 的表达升高,与对照组比较差异有统计学意义(P＜0.05或P＜0.01),而空肠组织差异无统计学意义(P＞0.05);而且CLP后肝、肺、肾、小肠组织TREM1 mRNA 表达与TNF-α mRNA 水平均呈显著正相关.结论 脓毒症时小鼠多器官TREM1基因的表达明显上调,可能与组织炎症反应失控及多脏器功能损害密切相关.     

胃癌组织中基质细胞因子及其受体与血管内皮生长因子的关系及意义

目的研究胃癌组织中基质细胞因子-1(stromal derived factor-1,SDF-1)及其受体(CXC chemokine receptor 4,CXCR4)的表达,探讨SDF-1/CXCR4轴与血管内皮生长因子(vascular endothelial growth factor,VEGF)表达的关系及其与胃癌浸润转移的相关性。方法采用免疫组织化学法检测62例胃癌患者的胃癌组织及癌旁组织中SDF-1,CXCR4及VEGF的表达情况。结果胃癌组织中SDF-1,CXCR4及VEGF的阳性表达率分别为85.4%,58.1%,62.9%,均高于癌旁组织45.2%,38.7%,35.5%,差异有统计学意义(P<0.05);SDF-1及CXCR4的表达水平在肿瘤病理分级、TNM分期、淋巴结及远处脏器转移上差异有统计学意义(P<0.05);SDF-1,CXCR4的表达与VEGF均呈正相关(r=0.394,P<0.05;r=0.526,P<0.05)。结论 SDF-1/CXCR4轴及VEGF在胃癌的生长、浸润、转移中发挥重要作用,可能成为未来药物治疗胃癌的重要靶点。     

大黄素对脓毒症急性肺损伤大鼠水通道蛋白1表达的影响

目的探讨大黄素对脓毒症急性肺损伤大鼠水通道蛋白1(AQP-1)表达的影响。方法成年雄性SD大鼠120只,体质量200～230g。大鼠分为6组:空白对照组、假手术组、模型组、大黄素低剂量预处理组、大黄素中剂量预处理组、大黄素高剂量预处理组,每组各20只。采用盲肠结扎穿孔法复制脓毒症大鼠模型,假手术组探查取出盲肠后还纳腹腔。各组按取材时间不同又分为造模后3、6、12、24小时4个时相点,每个时相点5只大鼠。分别用实时荧光多聚酶链反应(PCR)和蛋白免疫电泳(western-blot)法检测肺组织水通道蛋白1信使RNA(AQP-1mRNA)和蛋白的表达。结果各组3小时AQP-1表达差异无统计学意义,造模后6小时AQP-1逐渐降低,12小时达最低。大黄素中、高剂量预处理组12小时AQP-1均显著高于同剂量其他时间点(P0.01),且两组之间差异无统计学意义(P0.05)。结论脓毒症可造成大鼠AQP-1表达明显降低,早期预防性使用中高剂量大黄素可明显提高AQP-1的表达,从而有效减轻脓毒症大鼠肺水肿的程度。     

Induced expression and functional effects of aquaporin-1 in human leukocytes in sepsis

Introduction

Gene expression profiling was performed via DNA microarrays in leukocytes from critically ill trauma patients nonseptic upon admission to the ICU, who subsequently developed either sepsis (n = 2) or severe sepsis and acute respiratory distress syndrome (n = 3). By comparing our results with published expression profiling studies in animal models of sepsis and lung injury, we found aquaporin-1 to be differentially expressed across all studies. Our aim was to determine how the water channel aquaporin-1 is involved in regulating the immune response in critically ill patients during infection acquired in the ICU.

Methods

Following the results of the initial genetic screening study, we prospectively followed aquaporin-1 leukocyte expression patterns in patients with ICU-acquired sepsis who subsequently developed septic shock (n = 16) versus critically ill patients who were discharged without developing sepsis (n = 13). We additionally determined aquaporin-1 expression upon lipopolysaccharide (LPS) exposure and explored functional effects of aquaporin-1 induction in polymorphonuclear granulocytes (PMNs).

Results

Leukocyte aquaporin-1 expression was induced at the onset of sepsis (median 1.71-fold increase; interquartile range: 0.99 to 2.42, P = 0.012 from baseline) and was further increased upon septic shock (median 3.00-fold increase; interquartile range: 1.20 to 5.40, P = 0.023 from sepsis, Wilcoxon signed-rank test); no difference was observed between baseline and discharge in patients who did not develop sepsis. Stimulation of PMNs by LPS led to increased expression of aquaporin-1 in vitro, which could be abrogated by the NF-κB inhibitor EF-24. PMN hypotonic challenge resulted in a transient increase of the relative cell volume, which returned to baseline after 600 seconds, while incubation in the presence of LPS resulted in persistently increased cell volume. The latter could be abolished by blocking aquaporin-1 with mercury and restored by incubation in β-mercaptoethanol, which abrogated the action of mercury inhibition.

Conclusions

Aquaporin-1 is induced in leukocytes of patients with ICU-acquired sepsis and exhibits higher expression in septic shock. This phenomenon may be due to LPS-triggered NF-κB activation that can also lead to alterations in plasma membrane permeability.     

人结直肠癌趋化因子配体生物轴及干细胞标志物基因表达与临床病理

背景：趋化因子配体12/趋化因子受体4生物学轴在肿瘤的特异性转移中有重要作用,而干细胞标志物糖蛋白激素受体5基因的表达对于肿瘤的增殖和侵袭转移发挥重要作用。 目的：观察趋化因子配体12/趋化因子受体4生物轴以及干细胞标志物糖蛋白激素受体5基因在人结直肠癌组织中的表达变化及其与临床中的病理特征的关系。 方法：收集2013年1至6月辽宁省肿瘤医院收治100名结直肠癌患者为实验组,100名健康体检者为对照组,采用免疫组织化学SP法检测两组组织中趋化因子配体12、趋化因子受体4及干细胞标志物糖蛋白激素受体5 mRNA表达情况,并分析趋化因子配体12、趋化因子受体4及干细胞标志物糖蛋白激素受体5 mRNA表达与结直肠癌患者年龄、性别、肿瘤大小及部位、淋巴转移以及预后等临床病理特征的相关性。 结果与结论：趋化因子受体4、糖蛋白激素受体5 mRNA在结直肠癌组织中均有较高的表达率,但是趋化因子配体12 mRNA表达率降低。趋化因子受体4、干细胞标志物糖蛋白激素受体5 mRNA、趋化因子配体12 mRNA三者与结直肠癌患者的年龄、性别等患者临床特征无相关性,与结直肠癌的发病位置及其大小也无相关性,与结直肠癌组织是否淋巴转移具有相关性关,伴有淋巴转移的结直肠癌组织中干细胞标志物糖蛋白激素受体5 mRNA和趋化因子受体4的表达率更高,而趋化因子配体12 mRNA表达无显著变化;趋化因子受体4表达随肿瘤的恶性程度增高而增高;糖蛋白激素受体5表达于胃肠道肿瘤和脑肿瘤干细胞等表面,其表达随肿瘤的恶性程度增高而增高。提示结直肠癌组织中趋化因子受体4的表达增高,糖蛋白激素受体5基因表达增高,二者增高促进了结直肠癌组织生长及转移,糖蛋白激素受体5以及趋化因子配体12/趋化因子受体4轴的表达的调控,使其或将成为肿瘤诊断及治疗的重要新靶点。     

丙酮酸乙酯对脓毒症大鼠血清HMGB1表达的影响及其作用的研究

目的 观察丙酮酸乙酯(EP)对脓毒症大鼠血清高迁移率族蛋白1表达水平的影响,及其对动物多器官功能的干预作用.方法 采用雄性Wistar大鼠,以盲肠结扎穿孔法(CLP)建立脓毒症大鼠模型.80只大鼠随机分为假手术组(n=20)、脓毒症组(n=20)、EP早期治疗组(n=20)和EP晚期治疗组(n=20).各组分别于模型建立后24 h和48 h颈动脉置管留取标本后活杀,检测血清高迁移率族蛋白1(HMGB1)水平以及24 h丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、尿素氮(BUN)、肌酐(Cr)、肌酸激酶(CK)及动脉氧分压(PaO2)等各器官功能指标的变化.结果 脓毒症组、EP治疗组各时相点血清HMGB1水平均较假手术组高(P<0.01);EP早期组和EP晚期组HMGB1均较同时相点脓毒症组显著降低(P<0.01).与脓毒症组相比,EP治疗组血清ALT、AST、BUN、Cr、CK、PaO2水平均明显改善(P<0.01);脓毒症组24 h血清HMGB1与血清ALT、AST、BUN、Cr、CK、PaO2水平的变化之间存在显著相关性(P<0.01).结论 EP对脓毒症大鼠的重要器官功能具有保护作用,其机制可能与EP抑制HMGB1的释放有关.     

NOD1受体在腹主动脉阻断联合脂多糖注射诱导严重脓毒症大鼠肾脏中的表达

目的 通过比较NOD1受体在脓毒症大鼠和正常大鼠肾组织中的表达强度,探讨NOD1受体在脓毒症诱导肾损伤中的作用.方法 48只Wistar大鼠随机分为四组:假手术组(SHAM组),腹腔LPS注射组(LPS组),腹主动脉阻断组(AAC组),腹主动脉阻断+腹腔LPS注射组(AAC +LPS组).术后8h处死大鼠取血清和肾组织,测定血肌酐(Cr)和尿素氮(BUN)水平.HE染色观察肾脏组织病理损伤,免疫组化检测肾组织NOD1受体蛋白的表达和分布,PT-PCR检测肾组织NOD1受体mRNA的表达.结果 四组大鼠中,AAC +LPS组大鼠死亡率最高；与SHAM组比较,LPS组、AAC组和AAC+LPS组的血清Cr和BUN明显升高(P＜0.05),但LPS组和AAC组差异无统计学意义(P＞0.05)；免疫组化和RT-PCR显示,NOD1受体蛋白和mRNA的表达强度在SHAM组、LPS组、AAC组和AAC +LPS组依次递增(P＜0.05),而LPS组和AAC组差异无统计学意义(P＞0.05).结论 NOD1受体在严重脓毒症大鼠的肾脏损伤中发挥了重要的作用.