Inhaled activated protein C protects mice from ventilator-induced lung injury

Introduction  

Activated Protein C (APC), an endogenous anticoagulant, improves tissue microperfusion and endothelial cell survival in systemic inflammatory states such as sepsis, but intravenous administration may cause severe bleeding. We have thus addressed the role of APC delivered locally by inhalation in preventing acute lung injury from alveolar overdistention and the subsequent ventilator-induced lung injury (VILI). We also assessed the effects of APC on the activation status of Extracellular- Regulated Kinase 1/2 (ERK) pathway, which has been shown to be involved in regulating pulmonary responses to mechanical stretch.     

肺特异性蛋白与肺损伤

多种致病因素（如感染、炎症、创伤和毒物等）均可导致急、慢性肺损伤,肺损伤的典型病理生理学改变为肺泡毛细血管屏障通透性的改变和肺泡上皮细胞的损伤,是影响病情发展和预后的重要因素,其明确诊断和监测对疾病的治疗和预后有重要意义。目前肺部疾病的诊断主要依赖影像学方法,如x线平片或电子计算机X射线断层扫描技术（CT）。但肺损伤的早期微观改变无法通过影像学检查显示,只有损伤达到一定程度或一定的时间才会有所表现,并且存在放射损害、     

Simvastatin attenuates ventilator-induced lung injury in mice

Introduction

Different isoforms of nitric oxide synthases (NOS) and determinants of oxidative/nitrosative stress play important roles in the pathophysiology of pulmonary dysfunction induced by acute lung injury (ALI) and sepsis. However, the time changes of these pathogenic factors are largely undetermined.

Methods

Twenty-four chronically instrumented sheep were subjected to inhalation of 48 breaths of cotton smoke and instillation of live Pseudomonas aeruginosa into both lungs and were euthanized at 4, 8, 12, 18, and 24 hours post-injury. Additional sheep received sham injury and were euthanized after 24 hrs (control). All animals were mechanically ventilated and fluid resuscitated. Lung tissue was obtained at the respective time points for the measurement of neuronal, endothelial, and inducible NOS (nNOS, eNOS, iNOS) mRNA and their protein expression, calcium-dependent and -independent NOS activity, 3-nitrotyrosine (3-NT), and poly(ADP-ribose) (PAR) protein expression.

Results

The injury induced severe pulmonary dysfunction as indicated by a progressive decline in oxygenation index and concomitant increase in pulmonary shunt fraction. These changes were associated with an early and transient increase in eNOS and an early and profound increase in iNOS expression, while expression of nNOS remained unchanged. Both 3-NT, a marker of protein nitration, and PAR, an indicator of DNA damage, increased early but only transiently.

Conclusions

Identification of the time course of the described pathogenetic factors provides important additional information on the pulmonary response to ALI and sepsis in the ovine model. This information may be crucial for future studies, especially when considering the timing of novel treatment strategies including selective inhibition of NOS isoforms, modulation of peroxynitrite, and PARP.     

The complement regulators C1 inhibitor and soluble complement receptor 1 attenuate acute lung injury in rabbits

Because activation of the complement system plays a major role in the pathogenesis of acute lung injury, the availability of new specific complement inhibitors represents a promising therapeutic approach. In the present study we investigated pulmonary edema formation and pulmonary artery pressure (PAP) in acute complement-induced lung injury for possible therapeutic impact of the complement regulators C1 inhibitor and soluble complement receptor 1. Eighteen isolated and ventilated rabbit lungs were perfused with pooled normal human serum (NHS, final concentration 35%) in Krebs-Henseleit buffer in a recirculating system. Lung weight gain and PAP were continuously recorded. Complement activation was blocked by the addition of C1 inhibitor (1.0 U/mL, n = 6) or sCR 1 (2.0 microg/mL, n = 6). Lungs that received NHS without inhibitors served as controls (n = 6). This study was performed according to the Helsinki Declaration and approved by the local government. Application of NHS resulted in an increase of PAP within 20 min from 8+/-2 to 42+/-6 mmHg, which was significantly (P < 0.05) decreased by C1-Inh (25+/-5 mmHg) and sCRI (20 +/-3 mmHg). Moreover, pulmonary edema formation after NHS, as assessed by overall weight gain, was reduced by both C1-Inh and sCR1, compared with controls. These findings were paralleled with significantly decreased thromboxane release rates and reduced tissue deposition of C3c and C5b-9. C1 inhibitor and sCR1 attenuate the complement-induced pulmonary capillary leakage and PAP increase, indicating the protective effect of complement inhibition in isolated perfused rabbit lungs.     

晚期炎症介质在双重打击致急性肺损伤小鼠中作用的实验研究

目的 观察双重打击导致急性肺损伤(ALI)时肺组织中高迁移率族蛋白B1(HMGB1)随病程的浓度变化及其敛炎作用.方法 建立出血性休克后感染致ALI小鼠模型,观察病变过程中检测时间点肺组织HMGB1浓度、髓过氧化物酶(MPO)含量和肺泡膜通透性的变化,比较抗-HMGB1抗体干预治疗前后小鼠肺内MPO含量、肺泡膜通透性和肺组织病理学的改变.结果 出血性休克后感染致ALI小鼠肺组织HMGB1浓度于模型建立后4 h升高,16 h达高峰,48 h仍显著高于对照组.MPO水平于模型建立后4 h达峰值[(95.0 ±5.6)U/g肺组织].模型建市后4 h肺内伊文兰显著升高,于16 h达高峰[(33.3±2.3)g·mL-1·g-1肺组织].应用抗-HMGB1抗体可以显著降低肺内MPO浓度[抗体应用前(95.0±5.6)U/g肺组织、抗体应用后(50.0±6.4)pg·mL-1·mg-1肺组织]、减轻肺内伊文兰含量和肺组织病理损伤.结论 HMGB1是介导双重打击导致的ALI的重要迟发性炎症介质.     

Angiotensin receptor blockade attenuates cigarette smoke-induced lung injury and rescues lung architecture in mice

Chronic obstructive pulmonary disease (COPD) is a prevalent smoking-related disease for which no disease-altering therapies currently exist. As dysregulated TGF-β signaling associates with lung pathology in patients with COPD and in animal models of lung injury induced by chronic exposure to cigarette smoke (CS), we postulated that inhibiting TGF-β signaling would protect against CS-induced lung injury. We first confirmed that TGF-β signaling was induced in the lungs of mice chronically exposed to CS as well as in COPD patient samples. Importantly, key pathological features of smoking-associated lung disease in patients, e.g., alveolar injury with overt emphysema and airway epithelial hyperplasia with fibrosis, accompanied CS-induced alveolar cell apoptosis caused by enhanced TGF-β signaling in CS-exposed mice. Systemic administration of a TGF-β-specific neutralizing antibody normalized TGF-β signaling and alveolar cell death, conferring improved lung architecture and lung mechanics in CS-exposed mice. Use of losartan, an angiotensin receptor type 1 blocker used widely in the clinic and known to antagonize TGF-β signaling, also improved oxidative stress, inflammation, metalloprotease activation and elastin remodeling. These data support our hypothesis that inhibition of TGF-β signaling through angiotensin receptor blockade can attenuate CS-induced lung injury in an established murine model. More importantly, our findings provide a preclinical platform for the development of other TGF-β-targeted therapies for patients with COPD.     

重组白细胞介素-10/Fc融合蛋白对内毒素诱导急性肺损伤小鼠的实验干预作用

目的 探讨重组白细胞介素-10(rIL-10)/Fc融合蛋白对内毒素诱导的急性肺损伤(ALl)小鼠炎症调控作用及其机制.方法 向气管内注射脂多糖(LPS)制成ALl动物模型;rIL-10/Fc融合蛋白采用腹腔内给药方式.132只小鼠被随机均分为正常对照组、rIL-10/Fc对照组、ALl模型组、rIL-10/Fc治疗组.每组选择25只小鼠观察24 h存活率;其余用于检测支气管肺泡灌洗液(BALF)中自细胞数量,肿瘤坏死因子-a(TNF-a)和IL-1β水平,以及肺组织髓过氧化物酶(MPO)活性、肺组织湿/干重(W/D)比值;光镜下观察肺组织病理学改变.结果 注射LPS后4 h可引起BALF中TNF-a和IL-1β显著升高(P均＜0.01),rIL-10/Fc治疗组较ALI模型组有所降低,但差异无统计学意义;但在8 h和12 h,rIL-10/Fc融合蛋白能显著抑制BALF中TNF-a产生,在12 h抑制IL-1β产生;并明显改善LPS注射24 h后实验动物的存活率(P＜0.01).rIL-10/Fc对LPS诱导的ALI小鼠BALF中白细胞数量、肺组织MPO活性、肺组织W/D比值无显著改变.注射LPS 24 h后,肺组织出现了明显的炎性改变,但在rlL-10/Fc融合蛋白干预后没有出现显著的差异.结论 rIL-10/Fc融合蛋白能显著抑制LPS诱导的ALI小鼠肺促炎细胞因子产生,改善预后.     

Phosphatidic acid signaling mediates lung cytokine expression and lung inflammatory injury after hemorrhage in mice

Because phosphatidic acid (PA) pathway signaling may mediate many basic reactions involving cytokine-dependent responses, we investigated the effects of CT1501R, a functional inhibitor of the enzyme lysophosphatidic acid acyltransferase (LPAAT) which converts lysophosphatidic acid (Lyso-PA) to PA. We found that CT1501R treatment not only prevented hypoxia-induced PA increases and lyso-PA consumption in human neutrophils, but also prevented neutrophil chemotaxis and adherence in vitro, and lung injury and lung neutrophil accumulation in mice subjected to hemorrhage and resuscitation. In addition, CT1501R treatment prevented increases in mRNA levels and protein production of a variety of proinflammatory cytokines in multiple lung cell populations after blood loss and resuscitation. Our results indicate the fundamental role of PA metabolism in the development of acute inflammatory lung injury after blood loss.     

Platelet-activating factor mediates acid-induced lung injury in genetically engineered mice

Adult respiratory distress syndrome (ARDS) is an acute lung injury of high mortality rate, and the molecular mechanisms underlying it are poorly understood. Acid aspiration-induced lung injury is one of the most common causes of ARDS, characterized by an increase in lung permeability, enhanced polymorphonuclear neutrophil (PMN) sequestration, and respiratory failure. Here, we investigated the role of platelet-activating factor (PAF) and the PAF receptor (PAFR) gene in a murine model of acid aspiration-induced lung injury. Overexpression of the PAFR gene in transgenic mice enhanced lung injury, pulmonary edema, and deterioration of gas exchange caused by HCl aspiration. Conversely, mice carrying a targeted disruption of the PAFR gene experienced significantly less acid-induced injury, edema, and respiratory failure. Nevertheless, the efficiency of PMN sequestration in response to acid aspiration was unaffected by differences in PAFR expression level. The current observations suggest that PAF is involved in the pathogenesis of acute lung injury caused by acid aspiration. Thus, inhibition of this pathway might provide a novel therapeutic approach to acute lung injury, for which no specific pharmaceutical agents are currently available.     

小鼠肺爆震伤蛋白质组学研究

目的:通过检测不同时间点肺爆震伤小鼠肺蛋白质组学变化,探究肺爆震伤损伤机制。方法:60只健康雄性C57BL/6小鼠,随机（随机数字法）分为对照组、爆震后12 h组、24 h组、48 h组、72 h组及1周组（每组10只）。在北部战区总医院动物实验室进行实验,利用自主研发的精准爆震装置建立小鼠肺爆震伤模型;通过大体观察和...     

间质胶原酶在高氧所致急性肺损伤中的表达

目的 研究间质胶原酶(interstitial collagenase)在高氧所致急性肺损伤发病过程中的作用,探讨急性肺损伤的发病机理.方法 将72只C57BL/6小鼠随机分为正常对照组、高氧24 h组、高氧48 h组、高氧72 h组,每组18只;正常对照小鼠呼吸室内空气,高氧小鼠置于密闭的氧气室(氧浓度＞95%).评价肺损伤程度;逆转录-聚合酶链反应(RT-PCR)及免疫组织化学法测定肺组织间质胶原酶的表达及组织分布.统计分析采用单因素方差分析和q检验.结果 高氧能引起急性肺损伤;RT-PCR结果显示肺组织间质胶原酶mRNA表达量在暴露于高氧24 h后达(0.59±0.13)较对照组(0.07±0.01)明显增加(q≥3.15,P＜0.01),72 h达最高(0.68±0.12,q=3.78,P＜0.01);免疫组织化学研究显示间质胶原酶蛋白主要表达于气道上皮细胞、Ⅱ型肺泡上皮细胞和血管平滑肌细胞的胞浆中;间质胶原酶蛋白在气道上皮细胞的表达在高氧环境下24 h达(28.54±9.60)较对照组(13.48±4.32)明显升高(q≥2.62,P＜0.05),于48、72 h表达逐渐降低,分别为(20.32±5.68)和(15.24±4.65).结论 高氧能引起急性肺损伤伴间质胶原酶的表达增高,它们通过降解细胞外基质在高氧所致的急性肺损伤过程中发挥重要作用.     

Mechanical ventilation using non-injurious ventilation settings causes lung injury in the absence of pre-existing lung injury in healthy mice

Introduction  

Mechanical ventilation (MV) may cause ventilator-induced lung injury (VILI). Present models of VILI use exceptionally large tidal volumes, causing gross lung injury and haemodynamic shock. In addition, animals are ventilated for a relative short period of time and only after a 'priming' pulmonary insult. Finally, it is uncertain whether metabolic acidosis, which frequently develops in models of VILI, should be prevented. To study VILI in healthy mice, the authors used a MV model with clinically relevant ventilator settings, avoiding massive damage of lung structures and shock, and preventing metabolic acidosis.     

炎症因子在小鼠肾缺血再灌注损伤相关的肺损伤中的表达

目的观察炎症因子在肾缺血再灌注损伤小鼠全身和肺组织局部表达的变化,探讨炎症反应在肾缺血再灌注损伤相关的急性肺损伤中的作用。方法选取8～10周龄雄性C57BL/6小鼠30只,随机分为假手术组（Sham组n=10）、缺血再灌注组（I/R组n=10）和双肾切除组（BNx组n=10）。分别于术后6、24h留取小鼠肾和肺组织及血浆标本,观察肾和肺组织学改变,计算肺组织中中性粒细胞浸润数,称肺湿干重,计算肺湿干重比（W/D）;ELISA法检测小鼠血清和肺冲洗液中的IL-6、IL-1β、TNF-α的浓度,实时定量PCR检测小鼠肺组织IL-6、IL-1β、TNF-α基因表达,免疫组化检测肺组织IL-6、IL-1β和TNF-α蛋白的表达。结果 I/R组和BNx组小鼠术后24h时的BUN和Scr均显著高于Sham组（P均〈0.05）,I/R组和BNx组小鼠术后24h出现肺组织炎症细胞浸润、肺泡周围毛细血管出血和肺间质水肿,两组肺组织中性粒细胞计数均高于Sham组（P〈0.05）。术后6h时I/R组和BNx组小鼠血清IL-6、IL-1β和TNF-α浓度与Sham组相比显著升高（分别为606.32±59.07和300.22±169.73vs121.52±9.12pg/ml;443.93±91.98和959.47±184.46vs21.71±2.47pg/ml,119.67±21.66和132.33±62.64vs30.21±2.46pg/ml,P均〈0.05）;I/R组和BNx组小鼠肺组织冲洗液中IL-6、IL-1β和TNF-α的水平与Sham组比较显著升高（109.74±15.91和70.00±2.42vs37.69±7.96pg/mg,117.02±27.46和215.35±18.49vs42.10±5.20pg/mg,512.31±71.95和988.25±133.55vs52.76±12.82pg/mg,P〈0.05）;术后6h肺组织IL-6、IL-1β、TNF-α的mRNA表达较Sham组显著升高（P均〈0.05）;免疫组化显示了相似的结果。结论肾缺血再灌注损伤可以介导急性肺损伤,全身和肺组织局部的炎症因子表达明显升高可能参与了肾缺血再灌注损伤相关的肺损伤。     

急性肺损伤小鼠脾脏树突状细胞动态变化研究

目的 研究脂多糖(LPS)诱导急性肺损伤(ALI)小鼠脾脏树突状细胞(DC)数量改变和成熟状态,探讨ALI小鼠脾DC变化规律.方法 C57BL/6小鼠36只,随机(随机数字法)分为2组.①对照组(Con):小鼠气管内注射PBS 30 μL;②ALI组(ALI):气管内注射脂多糖(LPS)2 mg/kg复制ALI模型.后又按注射LPS或PBS后6、12、24 h三个时间点各分成三组,每组6只小鼠.光镜观察肺组织病理改变,测定肺损伤评分,计算肺湿质量/体质量比(LW/BW),酶联免疫吸附法(ELISA)检测肺组织匀浆中白细胞介素-6(IL-6)的含量,以反映肺组织炎症损伤程度.流式细胞仪(FCM)检测脾单细胞悬液中DC比例及表达CD80、MHCⅡ水平.结果 ALI组小鼠6、12、24h时点的肺LW/BW均明显高于对照组(P＜0.05).病理检测示ALI组小鼠肺泡间隔增宽、充血、出血及大量炎性细胞浸润等急性肺损伤病理改变.ALI组肺损伤评分及肺组织IL-6水平均显著高于对照组(P＜0.05).FCM检测显示,与对照组相比,ALI组小鼠脾脏DC呈一过性升高,ALI组12 h时点脾脏DC升高至(1.92±0.25)％,显著高于对照组(P＜0.01),24h时点降至基线水平(0.96±0.21)％.与对照组相比,ALI组脾脏DC表达CD80显著增加(P＜0.01);与ALI组6h相比,ALI组12h和24 h脾脏DC表达CD80显著升高(P＜0.05).ALI组与对照组及ALI组各时间点脾脏DC表达MHCⅡ的差异无统计学意义(P＞0.05).结论 ALI早期脾脏DC存在一过性升高,伴功能呈成熟状态,脾脏DC可能参与ALI炎症损伤的发生发展.     

Possible involvement of heparin-binding protein in transfusion-related acute lung injury

BACKGROUND: In antibody-mediated nonhemolytic transfusion reactions, transfusion-related acute lung injury (TRALI) tends to occur typically within 2 hours after a blood transfusion. White cell antibodies or immune complexes have been frequently shown to be associated with the syndrome, although the mechanisms by which they induce TRALI are poorly understood. The aim of this study was to characterize soluble mediators that are released from cells at an early stage after immune stimulation. STUDY DESIGN AND METHODS: To explore the mechanism of TRALI, an in vitro whole-blood cell culture assay was established in which cells were stimulated by human antibodies and the activation of neutrophils was monitored by a cell surface marker (Mac-1) with flow cytometry and by measurement of the release of soluble factors, including perforin, interleukin-6, tumor necrosis factor-alpha, and heparin-binding protein (HBP) with enzyme-linked immunosorbent assays. In addition, the involvement of two neutrophil FcgammaRs (FcgammaRIIIb and FcgammaRIIa, also known as CD16 and CD32, respectively) was examined during antibody-induced cell activation with anti-FcgammaR blocking antibodies. RESULTS: Substantial amounts of HBP were released within 30 minutes of stimulation by human antibodies, although other soluble mediators were not released within the same period. Furthermore, the release of HBP was mediated via signals through both FcgammaRIIIb and FcgammaRIIa. CONCLUSION: HBP appears to be one of the primary effector molecules of antibody-mediated nonhemolytic transfusion reactions including TRALI.     

Direct effects of protein S in ameliorating acute lung injury

Summary. Objective: Protein S may exert an anticoagulant activity by enhancing the anticoagulant activity of activated protein C and/or by directly inhibiting the prothrombinase complex. Protein S itself may also directly regulate inflammatory responses and apoptosis. The role of protein S in acute lung injury (ALI) was unknown. This study evaluated the effect of protein S on ALI in the mouse. Methods: Animal ALI was induced in C57/BL6 mice by intratracheal instillation of lipopolysaccharide (LPS). Mice were treated with protein S or saline by intraperitoneal injection 1 h before LPS instillation. Results: Activated protein or protein S alone and combined activated protein C + protein S therapy decreased inflammatory markers and cytokines in mice with acute lung injury. In LPS‐treated mice compared with controls ALI was induced as shown by significantly increased levels of total protein, tumor necrosis factor‐α, interleukin‐6 and monocyte chemoattractant protein‐1 in the bronchoalveolar lavage fluid. Mice with ALI treated with protein S had significantly decreased concentrations of tumor necrosis factor‐α and interleukin‐6 in the lung compared with untreated animals. Thrombin‐antithrombin III, a marker of the activity of the coagulation cascade, was unchanged. Protein S inhibited the expression of cytokines in vitro and increased activation of the Axl tyrosine kinase pathway in A549 epithelial cells. Conclusion: Protein S protects against LPS‐induced ALI, possibly by directly inhibiting the local expression of inflammatory cytokines without affecting coagulation.     

Flurbiprofen and HCT1026 protect mice against acute pancreatitis-associated lung injury

Impaired lung function in severe acute pancreatitis is the primary cause of morbidity and mortality in this condition. Flurbiprofen is a powerful nonsteroidal anti-inflammatory drug (NSAID). However, administration of this drug is associated with severe gastrointestinal side effects. The NO-releasing derivative of flubiprofen (nitroflurbiprofen, HCT1026) has recently been developed by the addition of a nitroxybutyl moiety to the flurbiprofen structure. This modification does not interfere with the anti-inflammatory activity of the drug but markedly reduces its ability to induce gastric injury. The effects of treatment with flurbiprofen and HCT1026 on the severity of pancreatitis and the associated lung injury were investigated in a mouse model. Acute pancreatitis was induced in mice by hourly intraperitoneal injections of cerulein. Flurbiprofen and HCT1026 were administered either 30 min before or 1 h after starting cerulein injections, and the severity of acute pancreatitis and associated lung injury were assessed. The severity of acute pancreatitis was determined by hyperamylasemia, neutrophil sequestration in the pancreas (pancreatic MPO activity), and pancreatic acinar cell injury/necrosis on histological examination of pancreas sections. The severity of acute pancreatitis-associated lung injury was assessed by neutrophil sequestration in the lungs (lung MPO activity) and by histological examination of lung sections. HCT1026 and flurbiprofen, given prophylactically as well as therapeutically, significantly reduced lung inflammation without having any significant effect on pancreatic injury. These results suggest the usefulness of flurbiprofen as well as HCT1026 as potential treatments for pancreatitis-associated lung injury.