Leukotoxin and pulmonary injury

In spite of the development of various antibiotics, management of elderly patients with pneumonia remains an important problem. It is suggested that adult respiratory distress syndrome (ARDS) and disseminated intravascular coagulation (DIC) often occur in elderly patients with pneumonia. Although neutrophils are suggested to be involved in the genesis of these conditions, details remain unknown. We demonstrated that a highly cytotoxic substance, 9,10-epoxy-12-octadecenoate, is biosynthesized from linoleate by human neutrophils, thus it was named leukotoxin. Leukotoxin was detected in lung lavages from patients with ARDS. In these lung lavages, increases in albumin concentration and angiotensin converting enzyme (ACE) activity were also observed. Similar results were observed in lung lavages from rats after exposure to hyperoxia for 60 hours in an experimental model of ARDS. Intravenous administration of leukotoxin (100 mumol/kg) caused lung edema. Albumin concentration and ACE activity were increased in lung lavages of rats receiving leukotoxin. In contrast, these changes were not observed in rats administered with linoleate. Furthermore, administration of leukotoxin (100 mumol/kg) caused coagulation abnormality, i.e., increase in fibrin-fibrinogen degradation products, decrease in fibrinogen, and prolongation of activated partial thromboplastin time and prothrombin time. Administration of linoleate did not induce these changes. It is indicated that O2- was produced by respiratory burst enzyme located in neutrophil plasma membrane, and that hydroxyl radicals derived from O2- by Fenton reaction were responsible for leukotoxin synthesis. From our results, leukotoxin, a product of hydroxyl radicals and linoleate, might be responsible for the genesis of ARDS and DIC.     

Neutrophil-derived epoxide, 9,10-epoxy-12-octadecenoate,induces pulmonary edema

We have observed that neutrophils biosynthesize linoleate epoxide, 9,10-epoxy-12-octadecenoate, and have named it leukotoxin because of its cytotoxic effect. In this experiment, the effect of leukotoxin on the lung was investigated. Acute effect of leukotoxin: Using Wistar rats, leukotoxin (100μmol/kg) was injected intravenously for the leukotoxin group, and linoleate (100μmol/kg) for the linoleate group. Physiological saline was injected as the control. Ten min after injection, rats were divided into 3 groups: (1) lungs were isolated, and lung wet weight, and dry weight were measured; (2) lung lavages were performed, and albumin concentration and activity of angiotensin converting enzyme (ACE) were measured; (3) morphological changes were studied by light and electron microscope. After administration of leukotoxin, lung wet weight/body weight ratios and dry weight/wet weight ratios were increased. Albumin concentration and ACE activity in lung lavages were also increased. Pulmonary edema was also confirmed by light microscopic findings. Alveolar epithelial cell damage and endothelium damage were also observed. Linoleate had no significant effect on these biochemical parameters and morphological findings. Subacute effect of leukotoxin: Twelve hr after administration of leukotoxin (50μmol/kg) or linoleate (50μmol/kg), the same studies were performed as in the acute experiments. Immediately after administration of leukotoxin, no significant effect was observed. However, 12 hr later similar changes were observed as in the acute experiments. Linoleate did not show any significant effect 12 hr after injection. These results indicate that leukotoxin biosynthesized by neutrophils might be closely related to the genesis of inflammatory edema.     

Neutrophil-derived epoxide, 9,10-epoxy-12-octadecenoate, induces pulmonary edema

We have observed that neutrophils biosynthesize linoleate epoxide, 9,10-epoxy-12-octadecenoate, and have named it leukotoxin because of its cytotoxic effect. In this experiment, the effect of leukotoxin on the lung was investigated. Acute effect of leukotoxin: Using Wistar rats, leukotoxin (100 mumol/kg) was injected intravenously for the leukotoxin group, and linoleate (100 mumol/kg) for the linoleate group. Physiological saline was injected as the control. Ten min after injection, rats were divided into 3 groups: (1) lungs were isolated, and lung wet weight, and dry weight were measured; (2) lung lavages were performed, and albumin concentration and activity of angiotensin converting enzyme (ACE) were measured; (3) morphological changes were studied by light and electron microscope. After administration of leukotoxin, lung wet weight/body weight ratios and dry weight/wet weight ratios were increased. Albumin concentration and ACE activity in lung lavages were also increased. Pulmonary edema was also confirmed by light microscopic findings. Alveolar epithelial cell damage and endothelium damage were also observed. Linoleate had no significant effect on these biochemical parameters and morphological findings. Subacute effect of leukotoxin: Twelve hr after administration of leukotoxin (50 mumol/kg) or linoleate (50 mumol/kg), the same studies were performed as in the acute experiments. Immediately after administration of leukotoxin, no significant effect was observed. However, 12 hr later similar changes were observed as in the acute experiments. Linoleate did not show any significant effect 12 hr after injection. These results indicate that leukotoxin biosynthesized by neutrophils might be closely related to the genesis of inflammatory edema.     

Nonspecificity of elevated angiotensin-converting enzyme activity in bronchoalveolar lavage fluid from high permeability lung edema states

Elevated levels of angiotensin-converting enzyme activity (ACE) in bronchoalveolar lavage fluid (BAL) have been used as a specific marker for pulmonary endothelial cell injury associated with high permeability lung edema. Alternatively, however, BAL-ACE elevations might reflect a nonspecific leak of plasma proteins into bronchoalveolar spaces. To investigate the cause of BAL-ACE elevations in high permeability lung injury states, we measured ACE and protein concentrations in BAL from isolated perfused rabbit lungs injured with oleic acid or hyperoxia. Although BAL-ACE was elevated, we found no increase in the BAL-ACE:protein ratio over values from control preparations, despite the presence of marked nonhydrostatic lung edema. We conclude that, in the experimental setting of nonhydrostatic lung edema, BAL-ACE elevations are no more helpful in identifying acute lung injury than are elevated BAL-protein levels.     

Leptin resistance protects mice from hyperoxia-induced acute lung injury

RATIONALE: Human data suggest that the incidence of acute lung injury is reduced in patients with type II diabetes mellitus. However, the mechanisms by which diabetes confers protection from lung injury are unknown. OBJECTIVES: To determine whether leptin resistance, which is seen in humans with diabetes, protects mice from hyperoxic lung injury. METHODS: Wild-type (leptin responsive) and db/db (leptin resistant) mice were used in these studies. Mice were exposed to hyperoxia (100% O(2)) for 84 hours to induce lung injury and up to 168 hours for survival studies. Alveolar fluid clearance was measured in vivo. MEASUREMENTS AND MAIN RESULTS: Lung leptin levels were increased both in wild-type and leptin receptor-defective db/db mice after hyperoxia. Hyperoxia-induced lung injury was decreased in db/db compared with wild-type mice. Hyperoxia increased lung permeability in wild-type mice but not in db/db mice. Compared with wild-type control animals, db/db mice were resistant to hyperoxia-induced mortality (lethal dose for 50% of mice, 152 vs. 108 h). Intratracheal instillation of leptin at a dose that was observed in the bronchoalveolar lavage fluid during hyperoxia caused lung injury in wild-type but not in db/db mice. Intratracheal pretreatment with a leptin receptor inhibitor attenuated leptin-induced lung edema. The hyperoxia-induced release of proinflammatory cytokines was attenuated in db/db mice. Despite resistance to lung injury, db/db mice had diminished alveolar fluid clearance and reduced Na,K-ATPase function compared with wild-type mice. CONCLUSIONS: These results indicate that leptin can induce and that resistance to leptin attenuates hyperoxia-induced lung injury and hyperoxia-induced inflammatory cytokines in the lung.     

The role of leukotriene B4 in the genesis of oxygen toxicity in the lung

Leukotriene B4 (LTB4) is a metabolite of arachidonic acid that has potent chemotactic activity for polymorphonuclear leukocytes (PMN). Pulmonary oxygen toxicity is considered to be a good model of an acute inflammatory lung injury, and an increase in the number of PMN is found in the lungs acutely injured by hyperoxia. In order to estimate the role of LTB4 responsible for this influx of PMN, we measured the LTB4 by radioimmunoassay in lung lavages of rats exposed to hyperoxia for 60 h. We found that the level of LTB4 in lung lavages in rats exposed to hyperoxia for 60 h increased significantly compared with that in normoxic control rats. At the same time, the marked increase in the number of PMN in lung lavages and the decrease in the activity of NADPH-cytochrome c reductase in lung microsomes were also observed. The administration of AA861, a 5-lipoxygenase inhibitor, reduced not only the increase in LTB4 but also the increase in the number of PMN in lung lavages of rats exposed to hyperoxia for 60 h. Furthermore, treatment with AA861 also protected the decrease in the activity of NADPH-cytochrome c reductase. The effects of AA861 on these parameters were observed in a dose-dependent fashion. In addition, there is a good correlation between the level of LTB4 and the number of PMN in the lavage of rats exposed to hyperoxia for 60 h with or without AA861 administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lung neutrophils in the adult respiratory distress syndrome. Clinical and pathophysiologic significance

Although neutrophils are of pathogenetic importance in various animal models of acute lung injury, their role in the adult respiratory distress syndrome (ARDS) is unclear. To study the significance of lung neutrophils in this disorder, patients with ARDS (n = 11) were evaluated by bronchoalveolar lavage within 24 h of admission to the intensive care unit. Patients with non-ARDS respiratory failure requiring mechanical ventilation (n = 4) and normal volunteers (n = 12) were also studied. Neutrophils constituted 67.6 +/- 9.8% of recovered lavage cells in patients with ARDS compared with only 4.0 +/- 2.4% of cells in mechanically ventilated control patients and 0.8 +/- 0.2% in normal volunteers (p less than 0.005, both comparisons). Furthermore, in patients with ARDS (n = 6) evaluated serially by bronchoalveolar lavage at 72-h intervals, neutrophil percentages decreased from 91 +/- 3.2% (initial lavage) to 42.8 +/- 12% (final lavage) (p less than 0.005). Lung neutrophils also predicted the severity of abnormalities in gas exchange and lung protein permeability. That is, the percentage of neutrophils correlated directly with the alveolar-arterial Po2 difference (r = 0.69, p less than 0.01) and lavage fluid total protein concentrations (r = 0.62, p less than 0.01). Because large numbers of lung neutrophils were present in these patients, ARDS lavage fluid was assayed for neutrophil mediators relevant to the pathogenesis of acute lung injury. Neutrophil elastase activity was not detected in any ARDS lavages, although elastase was antigenically present in most samples and appeared to be complexed to alpha-1-antitrypsin. In contrast to elastase, neutrophil collagenase was readily detectable in ARDS fluid.(ABSTRACT TRUNCATED AT 250 WORDS)     

烟雾吸入伤后血管紧张素转化酶的变化及意义

采用大鼠烟雾吸入伤模型，动态观察了伤后支气管肺泡灌洗液（BALF）及血浆中血管紧张素转化酶（ACE）活性的变化，辅以动脉血气分析，肺水量及BALF中总蛋白和白蛋白含量测定。结果发现，动物伤后出现急性呼吸衰竭和严重肺水肿，BALF中总蛋白和白蛋白含量均显著增加；血浆及BALF中ACE活性亦明显升高，且与BALF中蛋白水平的变化明显相关，提示ACE不仅是吸入伤后血管内皮细胞损伤的标志，而且可作为血管通透性增加及诊断严重吸入性损伤的早期敏感指标。     

Paraquat-induced neutrophil alveolitis: Reduction of the inflammatory response by pretreatment with endotoxin and hyperoxia

Paraquat toxicity often presents as acute lung injury that progresses into the irreversible form of the adult respiratory distress syndrome (ARDS). To assess the role of inflammatory cells in paraquat toxicity and its modulation by endotoxin/hyperoxia pretreatment, rats were injected with paraquat (35 mg/kg i.p.) and injury monitored by histologic study and bronchoalveolar lavage. Forty-eight hours after paraquat administration, acute lung injury was confirmed by histologic study and was associated with an increase in lavage LDH activity from 0.37 ± 0.12 U/mg protein to 0.83 ± 0.22 U/mg protein (P < 0.05). Lavage revealed a decrease in alveolar macrophages, 95.6 ± 0.6 to 20.6 ± 3.4%, and an increase in neutrophils from 1.6 ± 0.2 to 70.6 ± 6.1% (P < 0.001 in both comparisons). Pretreatment of rats with endotoxin and hyperoxia prior to paraquat administration prolonged survival (P < 0.005), elevated endogenous superoxide dismutase and catalase levels in the lung (P < 0.005, both comparisons), and significantly reduced the inflammatory cell changes (P < 0.001). The protective role of this pretreatment regimen in paraquat toxicity may reflect a complex modulating effect on several parameters critical to the pathogenesis of paraquat-induced lung injury.     

Granulocyte independence of pulmonary oxygen toxicity in the rat

The role of neutrophils in the mediation of severe normobaric hyperoxic lung injury has been studied by monitoring the effects of neutrophil depletion on a rat model of pulmonary oxygen toxicity. Pulmonary capillary permeability, assessed using an [125I]albumin lung permeability index (LPI), progressively increased with an increased duration of hyperoxia exposure in normal animals (LPI = 0.43 +/- 0.09 at 24 h; 0.95 +/- 0.17 at 48 h; 1.56 +/- 0.21 at 60 h), despite the absence of any significant tissue or bronchoalveolar lavage evidence of neutrophil infiltration until 60 h of hyperoxia exposure. Neutrophil depletion (using cyclophosphamide) blocked this late neutrophil infiltrate but failed to attenuate lung injury (LPI = 0.38 +/- 0.06 at 24 h; 0.89 +/- 0.16 at 48 h; 1.58 +/- 0.10 at 60 h; all p greater than .05 compared with leucocyte-replete/normal animals exposed to hyperoxia). The temporal dissociation of pulmonary neutrophil accumulation and pulmonary injury and the failure of effective neutrophil depletion to abrogate hyperoxic lung injury indicate that neutrophil polymorphs play no substantive role in the mediation of tissue injury in this model of severe pulmonary oxygen toxicity.     

Increased neutrophils in bronchoalveolar lavage fluids from a patient with pulmonary edema associated with pheochromocytoma

Pulmonary edema, both cardiogenic and noncardiogenic, has been reported as a manifestation of pheochromocytoma. We report a patient with pheochromocytoma complicated by acute pulmonary edema that appeared clinically noncardiogenic. The patient had an uncomplicated course and rapid resolution of pulmonary edema. Bronchoalveolar lavage fluids (BALF) showed a marked accumulation of neutrophils, suggesting involvement of neutrophil-mediated lung injury in noncardiogenic pulmonary edema associated with a pheochromocytoma.     

重组人促红细胞生成素对内毒素诱导的ALI/ARDS大鼠的干预作用

目的：观察重组人促红细胞生成素(rhEPO)对 ALI/ARDS大鼠模型肺部炎症及肺-毛细血管通透性的干预。方法24只雌性 SD大鼠随机分为正常对照组、ALI/ARDS组、EPO 低剂量组和 EPO 高剂量组。以腹腔注射内毒素进行造模,不同剂量的 rhEPO 进行干预。末次干预后收集BALF计数炎症细胞以及蛋白总量;计量肺湿/干重比;HE染色观察肺组织病理变化。结果与正常对照组比较,ALI/ARDS组肺组织病理损害严重,肺湿/干重比增加,BALF中白细胞总数、中性粒细胞、淋巴细胞以及蛋白总量均显著增加(P 值均<0.01);与 ALI/ARDS 组比较,EPO 低剂量组和EPO 高剂量组肺组织病理损害明显缓解,肺湿/干重比下降,BALF 中白细胞总数、中性粒细胞、淋巴细胞以及蛋白总量均显著下降(P值均<0.01),且 EPO 高剂量组效果优于 EPO 低剂量组(P <0.05或P<0.01)。结论 rhEPO 可以明显改善ALI/ARDS大鼠肺组织炎症水平,降低肺-毛细血管通透性,有效抑制 ALI/ARDS的发病进程。     

The function of lung and blood neutrophils in patients with the adult respiratory distress syndrome. Implications for the pathogenesis of lung infections.

Pulmonary infections are a frequent cause of morbidity and mortality in patients with the adult respiratory distress syndrome (ARDS), but the reason is uncertain. Because neutrophils are important for lung defense and are found in increased numbers in the bronchoalveolar lavage fluid of patients with ARDS, we compared the functional activities of neutrophils obtained from lavage fluid and pulmonary artery blood of 28 patients shortly after the onset of ARDS. The lavage fluids contained 81.3 +/- 9.9% neutrophils, of which more than 95% were viable by vital dye exclusion, and the total protein concentrations were increased (98.8 +/- 98.5 mg/dl). The production of superoxide anion and hydrogen peroxide by the neutrophils in lavage fluid was significantly impaired compared with simultaneously tested pulmonary artery and normal neutrophils, and the microbicidal activity of the lavage neutrophils for Staphylococcus aureus was significantly impaired. The migration of alveolar neutrophils in response to a variety of stimuli was markedly reduced as compared with both pulmonary artery and normal neutrophils. The alterations in superoxide anion production and chemotaxis could be reproduced by exposure of normal neutrophils to oxidants (glucose:glucose oxidase), but not to other mediators that have been found in ARDS lavage fluids. Although the pulmonary artery neutrophils from the same patients had impaired production of superoxide anion and hydrogen peroxide, their microbicidal activity and chemotactic responses were normal. These findings indicate that the function of alveolar neutrophils is impaired in the lungs of patients with ARDS. This could contribute to the high incidence of pulmonary infections in these patients.     

Activation of the complement system in the adult respiratory distress syndrome

The adult respiratory distress syndrome (ARDS) is an acute pulmonary disorder characterized by the accumulation of neutrophils within the lower respiratory tract. Because activation of the complement system can generate C5a, a potent neutrophil chemoattractant, complement activation was assessed in both serum and bronchoalveolar lavage fluid obtained from 10 patients with ARDS and compared with that from normal control subjects. Crossed immunoelectrophoresis was used to determine activation of the complement components C3 and properdin factor B (PFB), and radioimmunoassay was used to determine the presence of C5a. Complement activation was not detected either in the plasma or in the lung epithelial lining fluid of the control subjects. In contrast, evidence of C3 activation was found in the plasma of 50% of the patients with ARDS when initially studied; likewise, C3 activation, PFB activation, and C5a could all be detected in the epithelial lining fluid of all patients with ARDS with a single exception. Follow-up bronchoalveolar lavages revealed decreased amounts of C3 activation and C5a 2 to 7 days after the onset of ARDS, and the complement activation had resolved when the patients with ARDS had completely recovered. To determine if the C5a in bronchoalveolar lavage fluid could be responsible for the influx of neutrophils observed in ARDS, epithelial lining fluids obtained from both normal control subjects and from patients with ARDS were fractionated by molecular sieve chromatography. Two distinct fractions of chemotactic activity were found in the ARDS bronchoalveolar lavage fluid.(ABSTRACT TRUNCATED AT 250 WORDS)     

普拉格雷对海水吸入型急性肺损伤的作用分析

目的探讨海水吸入型急性肺损伤中血小板与中性粒细胞的黏附情况,以及普拉格雷对其的干预作用。 方法SD大鼠随机分为海水吸入1、2 h两个大组,组内随机分为空白对照组、海水处理组、溶剂处理组与普拉格雷处理组,每组8只大鼠。海水处理组在大鼠气管内灌注海水,溶剂处理组和普拉格雷处理组在海水处理之前4 h分别给予羟甲基纤维素钠溶液(CMC-Na)和普拉格雷灌胃处理。分别进行各组的病理切片HE染色,检测各组肺组织湿干比、血浆中炎症因子浓度,流式细胞术下检测血小板活化率以及与中性粒细胞的黏附情况,并进行肺泡灌洗液蛋白浓度测定以及髓过氧化物酶(MPO)活性测定。 结果与正常对照组比较,气管内滴入海水后大鼠肺部组织出现明显炎症和水肿,HE染色显示其组织结构紊乱,肺泡间质充血水肿,并有大量炎症细胞浸润,肺泡间隔明显增厚,ELISA法测得全身炎症因子,如TNF-α、IL-1β以及TXB2的表达增高,血小板与中性粒细胞黏附率显著增加,肺泡灌洗液蛋白定量以及MPO活性增加,并且海水吸入2 h较1 h各项指标增高更为显著。普拉格雷干预可显著减轻海水导致的肺组织损伤,减轻肺组织结构紊乱与炎症细胞浸润,减少炎症因子TNF-α、IL-1β以及TXB2的释放,并且抑制血小板的活化以及与中性粒细胞的黏附。 结论海水吸入型急性肺损伤中血小板与中性粒细胞的黏附率明显升高,普拉格雷可能通过降低此指标对肺损伤产生保护作用。     

Mepacrine but not methylprednisolone decreases acute edematous lung injury after injection of phorbol myristate acetate in rabbits

A good model of the adult respiratory distress syndrome (ARDS) is intravenously injected phorbol myristate acetate (PMA), which causes pulmonary sequestration of neutrophils and a neutrophil-dependent acute edematous lung injury in rabbits. In the present study, pretreatment of rabbits with the antimalarial agent, mepacrine, prevented lung edema after injection of PMA without altering initial accumulations of neutrophils in the lung. Mepacrine also decreased oxygen radical production and degranulation by neutrophils stimulated by PMA in vitro. In contrast, pretreatment with methylprednisolone did not decrease edematous lung injury in rabbits given PMA nor did it inhibit O2 radical production or degranulation by neutrophils treated with PMA in vitro. Our results suggest that agents that modify neutrophil function may be useful in decreasing lung injury after PMA treatment and, perhaps, in treating patients with ARDS.     

Angiotensin converting enzyme in bronchoalveolar lavage in ARDS

Angiotensin converting enzyme (ACE) is present in the endothelial cells of the normal lung where it converts angiotensin I to angiotensin II and inactivates bradykinin. It has been suggested that during endothelial injury ACE is sloughed into the blood, and that if the alveolar capillary membrane is injured, also into the alveolar lining fluid. Seven patients with adult respiratory distress syndrome (ARDS), were compared to 11 normal control subjects, nine patients with sarcoidosis, and six with idiopathic pulmonary fibrosis. Total, differential cell counts and ACE determinations were performed on bronchoalveolar lavage fluid in the ARDS group. ACE was detectable in the BAL of all but one ARDS patient. It was concluded that BAL ACE is elevated in some ARDS patients, especially those with infectious causes of lung injury. Increased ACE may reflect endothelial damage or local increase in ACE production in response to sepsis.     

Differential effects of oxygen and barotrauma on lung injury in the neonatal piglet

In order to differentiate the effects of hyperoxia and barotrauma in the pathogenesis of acute neonatal lung injury, piglets were either hyperventilated (Paco2, 15-20 torr) for 48 hours with 100% oxygen (Group I), hyperventilated with 21% oxygen (Group II), normally ventilated (Paco2, 40-45 torr) with 100% oxygen (Group III), or normally ventilated with 21% O2 (Group IV) and compared to unventilated controls. Pulmonary function was tested, and biochemical indicators of lung injury were analyzed in tracheo-bronchial aspirates at 0, 24, and 48 hours. Bronchoalveolar lavage fluid was analyzed for surfactant composition and activity at the end of the study. At 48 hours, hyperoxic, hyperventilated piglets had significantly decreased dynamic lung compliance (30%) and increased pulmonary resistance (16%), aspirate cell count (190%), elastase activity (88%), albumin (214%), and total protein (150%) concentration. Qualitative light microscopy showed moderate to severe atelectasis, fibrinous exudate, edema, and inflammation. Normoxic, hyperventilated animals had comparable changes in pulmonary mechanics, but significantly milder cellular, biochemical, and morphologic changes. In hyperoxic, normocarbic animals pulmonary physiologic, cellular, and biochemical variables changed comparably to hyperoxic, hyperventilated animals; the pathologic changes were intermediate between hyperoxic, hyperventilated and normoxic, hyperventilated piglets. Normoxic, normocarbic animals had no significant changes in most variables over 48 hours; on morphologic examination their lungs were similar to unventilated controls and showed only mild edema. Surfactant had normal biophysical activity in all animals. Our results demonstrate that hyperoxia causes more significant physiologic, inflammatory, and histologic changes than barotrauma alone. Future attempts to prevent lung injury in neonates should be directed primarily at oxygen toxicity.     

Transforming growth factor beta contributes to lung leak in rats given interleukin-1 intratracheally

Interleukin-1 (IL-1) is increased in lung lavages obtained from patients with acute lung injury (ALI) and administering recombinant human IL-1alpha (rhIL-1alpha) (50 ng) intratracheally causes an acute, neutrophil-dependent, oxidative lung leak in rats that closely resembles human ALI. In the present work, the authors tested the hypothesis that transforming growth factor beta (TGFbeta) contributes to the lung inflammation and injury that develops in rats given IL-1 intratracheally. They found that intravenous administration of a monoclonal antibody to TGFbeta (1.D.11.16, 0.5 mg/kg) attenuated lung injury responses, specifically lung leak index, lung lavage protein concentrations, and blood oxygenation abnormalities, that are observed 5 hours after intratracheal instillation of IL-1 in rats, but did not decrease indices of lung inflammation, specifically myeloperoxidase (MPO) activity in lung tissue, neutrophil counts in lung lavage, and cytokine-induced neutrophil chemoattractant (CINC) levels in lung lavage, in rats given IL-1 intratracheally. The results suggest that TGFbeta contributes to lung leak, but not lung inflammation, following intratracheal administration of IL-1 in rats.     

Serum ferritin elevation and acute lung injury in rats subjected to hemorrhage: reduction by mepacrine treatment

Ferritin regulates iron levels and, for unknown reasons, serum ferritin concentrations are increased in patients at risk for and with acute lung injury (ALI) and multiple organ failure. Uncomplexed iron could exacerbate the toxicity of the increased oxidative stress that occurs in patients with ALI and multiple organ failure and thereby contribute to disease. In the present investigation, the authors found that serum and lung lavage ferritin concentrations increased in hemorrhaged rats that develop ALI as manifested by increased lung inflammation (increased lung lavage leukocyte counts and lung myeloperoxidase activities) and increased lung leak (increased lung lavage protein concentrations). Treatment with mepacrine, a phospholipase A2 inhibitor, attenuated the increases in serum and lung lavage ferritin concentrations, lung inflammation, and lung leak that occur in rats subjected to hemorrhage. The findings show that serum and lung ferritin levels increase and may play a role in the development of acute lung injury caused by hemorrhage.