Importance of interleukin-8 in the development of reexpansion lung injury in rabbits

Rarely fatal bilateral re-expansion pulmonary edema after inserting a chest tube for unilateral spontaneous pneumothorax: a case report

We describe a case of a 32-year-old man who died due to bilateral re-expansion pulmonary edema (RPE) following the insertion a chest tube for unilateral spontaneous pneumothorax. Fifteen minutes after inserting the chest tube, the patient with right spontaneous pneumothorax was diagnosed with right re-expansion edema by chest radiograph. Although multiple treatments were administered, the patient died. However, the findings from autopsy showed bilateral RPE existed in the decedent but not unilateral RPE. Autopsy, microscopic examination, and clinical records concluded that the cause of death was acute cardiac and respiratory failure due to bilateral re-expansion pulmonary edema following unilateral spontaneous pneumothorax. Bilateral RPE due to a unilateral pneumothorax is quite rare in clinical and forensic practice. To the best of our knowledge, this is the first time that the pathological changes of RPE have been described by gross and microscopic examinations. This case is reported to provide histopathologic references for diagnosis of RPE and indicate that combining death investigation, pathological findings and clinical courses plays a vital role in diagnosis of RPE in forensic pathology.

Lung Atelectasis Promotes Immune and Barrier Dysfunction as Revealed by Transcriptome Sequencing in Female Sheep

BACKGROUND

Pulmonary atelectasis is frequent in clinical settings. Yet there is limited mechanistic understanding and substantial clinical and biologic controversy on its consequences. The authors hypothesize that atelectasis produces local transcriptomic changes related to immunity and alveolar-capillary barrier function conducive to lung injury and further exacerbated by systemic inflammation.

METHODS

Female sheep underwent unilateral lung atelectasis using a left bronchial blocker and thoracotomy while the right lung was ventilated, with (n = 6) or without (n = 6) systemic lipopolysaccharide infusion. Computed tomography guided samples were harvested for NextGen RNA sequencing from atelectatic and aerated lung regions. The Wald test was used to detect differential gene expression as an absolute fold change greater than 1.5 and adjusted P value (Benjamini-Hochberg) less than 0.05. Functional analysis was performed by gene set enrichment analysis.

RESULTS

Lipopolysaccharide-unexposed atelectatic versus aerated regions presented 2,363 differentially expressed genes. Lipopolysaccharide exposure induced 3,767 differentially expressed genes in atelectatic lungs but only 1,197 genes in aerated lungs relative to the corresponding lipopolysaccharide-unexposed tissues. Gene set enrichment for immune response in atelectasis versus aerated tissues yielded negative normalized enrichment scores without lipopolysaccharide (less than -1.23, adjusted P value less than 0.05) but positive scores with lipopolysaccharide (greater than 1.33, adjusted P value less than 0.05). Leukocyte-related processes (e.g., leukocyte migration, activation, and mediated immunity) were enhanced in lipopolysaccharide-exposed atelectasis partly through interferon-stimulated genes. Furthermore, atelectasis was associated with negatively enriched gene sets involving alveolar-capillary barrier function irrespective of lipopolysaccharide (normalized enrichment scores less than -1.35, adjusted P value less than 0.05). Yes-associated protein signaling was dysregulated with lower nuclear distribution in atelectatic versus aerated lung (lipopolysaccharide-unexposed: 10.0 ± 4.2 versus 13.4 ± 4.2 arbitrary units, lipopolysaccharide-exposed: 8.1 ± 2.0 versus 11.3 ± 2.4 arbitrary units, effect of lung aeration, P = 0.003).

CONCLUSIONS

Atelectasis dysregulates the local pulmonary transcriptome with negatively enriched immune response and alveolar-capillary barrier function. Systemic lipopolysaccharide converts the transcriptomic immune response into positive enrichment but does not affect local barrier function transcriptomics. Interferon-stimulated genes and Yes-associated protein might be novel candidate targets for atelectasis-associated injury.

EDITOR’S PERSPECTIVE

Protective effects of melatonin on lung damage associated with one-lung ventilation: An experimental study

Background

This study aims to investigate the protective effect of melatonin on lung damage induced by one-lung ventilation in a rat model.

Methods

A total of 20 healthy, Sprague-Dawley male rats were randomized into two equal groups as control (n=10) and melatonin groups (n=10). The control group underwent 60 min of one-lung ventilation, followed by 30 min of two-lung ventilation. In the melatonin group, the rats were administered 10 mg/kg melatonin intraperitoneally 10 min before the start of the experiment. At the end of both ventilation periods, tissue samples were obtained from the lungs of the control and melatonin groups for biochemical analysis and histopathological examinations. Tissue superoxide dismutase, malondialdehyde, and tumor necrosis factor-alpha levels were measured. Lung tissue samples were examined based on the presence and amount of alveolar congestion, intra-alveolar bleeding, and leukocyte and lymphocyte infiltration.

Results

At the end of the study, lung tissue malondialdehyde (3.8±0.9 vs. 1.8±0.8 μM; p<0.001) and tumor necrosis factor-alpha levels (47.2±15.0 vs. 21.8±7.2 pg/mL; p<0.001) of the melatonin group were found to significantly decrease, compared to the control group. Superoxide dismutase levels of the melatonin group increased at the end of both ventilation periods, and the increase at the end of one-lung ventilation was found to be statistically significant (0.6±0.2 vs. 1.3±0.7 U/mL; p<0.05). Histopathological examination demonstrated that the tissue damage was less in the melatonin group. There was a significant decrease in the alveolar congestion in this group (p=0.0401). Although other histopathological parameters decreased in the melatonin group, no significant difference was found.

Conclusion

Our study results demonstrate that melatonin has protective effects on the lung damage induced by one-lung ventilation both at biochemical and histopathological levels in rats.

Reexpansion Pulmonary Edema After Atrial Septal Defect Closure Through Right-Sided Minithoracotomy

We describe a patient with reexpanded pulmonary edema after atrial septal defect closure through a right-sided minithoracotomy. After reexpansion of the right lung after weaning from cardiopulmonary bypass, a large amount of serous slight-hemorrhagic bronchial secretions spilled out from the right bronchus. Positive pressure ventilation and differential ventilation were used. We found no bleeding and decreased secretions 24 hours after the onset of reexpanded pulmonary edema. The patient was extubated 42 hours after the operation. To the best of our knowledge, this is the first case report of the development of reexpansion pulmonary edema during a routine minimally invasive operation for atrial septal defect.

Low tidal volume ventilation with low PEEP during surgery may induce lung inflammation

Background

Compared to conventional tidal volume ventilation, low tidal-volume ventilation reduces mortality in cased of acute respiratory distress syndrome. The aim of the present study is to determine whether low tidal-volume ventilation reduces the production of inflammatory mediators in the lungs and improves physiological status during hepatic surgery.

Methods

We randomly assigned patients undergoing hepatectomy into 2 groups: conventional tidal-volume vs. low tidal-volume (12 vs. 6 mL•kg⁻¹ ideal body weight) ventilation with a positive end-expiratory pressure of 3 cm H₂O. Arterial blood and airway epithelial lining fluid were sampled immediately after intubation and every 3 h thereafter.

Results

Twenty-five patients were analyzed. No significant changes were found in hemodynamics or acid–base status during the study. Interleukin-8 was significantly elevated in epithelial lining fluid from the low tidal-volume group. Oxygenation evaluated immediately after admission to the post-surgical care unit was significantly worse in the low tidal-volume group.

Conclusions

Low tidal-volume ventilation with low positive end-expiratory pressure may lead to pulmonary inflammation during major surgery such as hepatectomy.

Trial registration

The effect of ventilatory tidal volume on lung injury during hepatectomy that requires transient liver blood flow interruption. UMIN000021371 (03/07/2016); retrospectively registered

An uncommon complication of a common clinical scenario: exploring reexpansion pulmonary edema with a case report and literature review

Reexpansion pulmonary edema (RPE) is a rare complication that can occur after rapid reinflation of the lung following thoracentesis of a pleural effusion or chest tube drainage of pneumothorax. The severity in clinical presentation can be widely varied from radiographic changes only to rapidly progressive respiratory failure requiring mechanical ventilation. The quick nature of onset and potential for serious decline in a previously stable patient makes it important to prepare, recognize, diagnose, and appropriately manage patients who develop RPE. The standard treatment for RPE consists of supportive care, and there are certain measures that may be taken to reduce the risk, including limiting the amount drained and avoiding excessive negative pleural pressure. Exactly how to prevent RPE remains unclear, however, and varying recommendations exist. This is a case report of RPE after thoracentesis for a pleural effusion and a brief review of literature to date, including potential preventative strategies.

A novel method for right one-lung ventilation modeling in rabbits

There is no standard method by which to establish a right one-lung ventilation (OLV) model in rabbits. In the present study, a novel method is proposed to compare with two other methods. After 0.5 h of baseline two-lung ventilation (TLV), 40 rabbits were randomly divided into sham group (TLV for 3 h as a contrast) and three right-OLV groups (right OLV for 3 h with different methods): Deep intubation group, clamp group and blocker group (deeply intubate the self-made bronchial blocker into the left main bronchus, the novel method). These three methods were compared using a number of variables: Circulation by heart rate (HR), mean arterial pressure (MAP); oxygenation by arterial blood gas analysis; airway pressure; lung injury by histopathology; and time, blood loss, success rate of modeling. Following OLV, compared with the sham group, arterial partial pressure of oxygen and arterial hemoglobin oxygen saturation decreased, peak pressure increased and lung injury scores were higher in three OLV groups at 3 h of OLV. All these indexes showed no differences between the three OLV groups. During right-OLV modeling, less time was spent in the blocker group (6±2 min), compared with the other two OLV groups (13±4 min in deep intubation group, P<0.05; 33±9 min in clamp group, P<0.001); more blood loss was observed in clamp group (11.7±2.8 ml), compared with the other two OLV groups (2.3±0.5 ml in deep intubation group, P<0.001; 2.1±0.6 ml in blocker group, P<0.001). The first-time and final success rate of modeling showed no differences among the three OLV groups. Deep intubation of the self-made bronchial blocker into the left main bronchus is an easy, effective and reliable method to establish a right-OLV model in rabbits.

Antiinflammatory effect of sevoflurane in open lung surgery with one-lung ventilation

Aim

To prospectively assess the antiinflammatory effect of volatile anesthetic sevoflurane in patients undergoing open lung surgery with one lung ventilation (OLV).

Methods

This prospective, randomized study included 40 patients undergoing thoracic surgery with OLV (NCT02188407). The patients were randomly allocated into two equal groups that received either propofol or sevoflurane. Four patients were excluded from the study because after surgery they received blood transfusion or non-steroid antiinflammatory drugs. Inflammatory mediators (interleukins 6, 8, and 10, C-reactive protein [CRP], and procalcitonin) were measured perioperatively. The infiltration of the nonoperated lung was assessed on chest x-rays and the oxygenation index was calculated. The major postoperative complications were counted.

Results

Interleukin 6 levels were significantly higher in propofol than in sevoflurane group (P = 0.014). Preoperative CRP levels did not differ between the groups (P = 0.351) and in all patients they were lower than 20 mg/L, but postoperative CRP was significantly higher in propofol group (31 ± 6 vs 15 ± 7 ng/L; P = 0.035); Pre- and postoperative procalcitonin was within the reference range (<0.04 µg/L) in both groups. The oxygenation index was significantly lower in propofol group (339 ± 139 vs 465 ± 140; P = 0.021). There was no significant difference between the groups in lung infiltrates (P = 0.5849). The number of postoperative adverse events was higher in propofol group, but the difference was not-significant (5 vs 1; P = 0.115).

Conclusion

The study suggests an antiinflammatory effect of sevoflurane in patients undergoing thoracotomy with OLV.

Effects of early and late pneumothorax drainage on the development of pulmonary oedema

We analyzed the effects of pneumothorax duration and early or late drainage on lung histology and biological markers associated with inflammation, alveolar fluid clearance, and pulmonary oedema formation. Pneumothorax was induced by injecting air into the thorax of anaesthetized rats, which were randomized according to duration of pneumothorax [5 (PTX5) or 30 (PTX30)min] and further divided to be drained (D) or not (ND). ND rats were euthanized at 5 and 30min. In D groups, pneumothorax was drained and rats breathed spontaneously for 30min. PTX30-ND, compared to PTX5-ND, showed higher alveolar collapse and oedema, type III procollagen, caspase-3, epithelial sodium channel-α, and aquaporin (AQP)-1 mRNA expression, and epithelial and endothelial damage, with reduced cystic fibrosis transmembrane conductance regulator (CFTR) and AQP-3 expression. PTX5-D, compared to PTX30-D, showed less alveolar hyperinflation, oedema, and alveolar-capillary damage, with reduced interleukin-6, caspase-3, AQP-5, and Na,K-ATPase-α and -β expression, and increased CFTR expression. In conclusion, longer duration pneumothorax exacerbated lung damage, oedema, and inflammation.

Re-expansion pulmonary edema: evaluation of risk factors in 173 episodes of spontaneous pneumothorax

BACKGROUND

The precise incidence and clinical features of re-expansion pulmonary edema (RPE) are unclear, and they vary among reports. In this study, we assessed the incidence, risk factors, and outcomes of patients with RPE over a 3-yr period in a general hospital, with the goal of proposing a primary intervention for pneumothorax.

METHODS

We retrospectively reviewed records of inpatients with spontaneous pneumothorax treated by tube thoracostomy between October 2007 and December 2010.

RESULTS

A total of 173 episodes of spontaneous pneumothorax occurred in 156 patients. The incidence of RPE was 27/173 (15.6%). Symptom duration and pneumothorax size were significant risk factors for RPE, and the occurrence of RPE was independent of primary treatment of spontaneous pneumothorax. Among the patients with RPE, 18 (67%) were symptomatic. Five patients (18.5%) were treated with temporary oxygen, however, 21 patients (78%) did not need any treatment. All patients survived and none required mechanical ventilation. The occurrence of RPE did not influence the clinical outcome.

CONCLUSIONS

The risk of developing RPE increases with an increased duration or size of pneumothorax. Our results suggest that the methods of primary intervention, including prompt suction, do not affect the onset of RPE. Close observation is always required regardless of the intervention because of the potentially fatal complications.

Propofol attenuates pulmonary injury induced by collapse and reventilation of lung in rabbits

Propofol is an anesthetic drug with antioxidant and anti-inflammatory properties. We previously found that propofol attenuated lipopolysaccharide-induced acute lung injury in rabbits. This study was performed to evaluate the effects of propofol on lung injury caused by collapse and reventilation in rabbits. The wet/dry weight ratio of the lung, lung injury scores, percentage of polymorphonuclear leukocytes, albumin concentration, malondialdehyde, and interleukin-8 levels in bronchoalveolar lavage fluid were significantly increased in both lungs of the reventilation group. The degree of increase in these parameters was more significant in the right (reventilated) than in the left (non-reventilated) lung. Propofol attenuated these changes. These findings suggest that reventilation of a collapsed lung can cause injury in the contralateral non-reventilated lung as well as the reventilated lung. Propofol may provide a beneficial effect on lung injury induced by collapse and reventilation of the lung.

Mast-cell-releasing tryptase triggers acute lung injury induced by small intestinal ischemia-reperfusion by activating PAR-2 in rats

Mast cell has been demonstrated to be involved in the small intestinal ischemia-reperfusion (IIR) injury, however, the precise role of tryptase released from mast cell on acute lung injury(ALI) induced by IIR remains to be elucidated, our study aimed to observe the roles of tryptase on ALI triggered by IIR and its underlying mechanism. Adult SD rats were randomized into sham-operated group, sole IIR group in which rats were subjected to 75 min superior mesenteric artery occlusion followed by 4 h reperfusion, or IIR being respectively treated with cromolyn sodium, protamine, and compound 48/80. The above agents were, respectively, administrated intravenously 5 min before reperfusion. At the end of experiment, lung tissue was obtained for assays for protein expressions of tryptase and mast cell protease 7 (MCP7) and protease-activated receptor 2 (PAR-2). Pulmonary mast cell number and levels of IL-8 were quantified. Lung histologic injury scores and lung water content were measured. IIR resulted in lung injury evidenced as significant increases in lung histological scores and lung water contents, accompanied with concomitant increases of expressions of tryptase and MCP7, and elevations in PAR-2 expressions and IL-8 levels in lungs. Stabilizing mast cell with cromolyn sodium and inhibiting tryptase with protamine significantly reduced IIR-mediated ALI and the above biochemical changes while activating mast cell with compound 48/80 further aggravated IIR-mediated ALI and the increases of above parameters. Tryptase released from mast cells mediates ALI induced by intestinal ischemia-reperfusion by activating PAR-2 to produce IL-8.

Role of reactive oxygen and nitrogen species in the vascular responses to inflammation

Inflammation is a complex and potentially life-threatening condition that involves the participation of a variety of chemical mediators, signaling pathways, and cell types. The microcirculation, which is critical for the initiation and perpetuation of an inflammatory response, exhibits several characteristic functional and structural changes in response to inflammation. These include vasomotor dysfunction (impaired vessel dilation and constriction), the adhesion and transendothelial migration of leukocytes, endothelial barrier dysfunction (increased vascular permeability), blood vessel proliferation (angiogenesis), and enhanced thrombus formation. These diverse responses of the microvasculature largely reflect the endothelial cell dysfunction that accompanies inflammation and the central role of these cells in modulating processes as varied as blood flow regulation, angiogenesis, and thrombogenesis. The importance of endothelial cells in inflammation-induced vascular dysfunction is also predicated on the ability of these cells to produce and respond to reactive oxygen and nitrogen species. Inflammation seems to upset the balance between nitric oxide and superoxide within (and surrounding) endothelial cells, which is necessary for normal vessel function. This review is focused on defining the molecular targets in the vessel wall that interact with reactive oxygen species and nitric oxide to produce the characteristic functional and structural changes that occur in response to inflammation. This analysis of the literature is consistent with the view that reactive oxygen and nitrogen species contribute significantly to the diverse vascular responses in inflammation and supports efforts that are directed at targeting these highly reactive species to maintain normal vascular health in pathological conditions that are associated with acute or chronic inflammation.

Tube thoracostomy: complications and its management

Background. Tube thoracostomy is widely used throughout the medical, surgical, and critical care specialities. It is generally used to drain pleural collections either as elective or emergency. Complications resulting from tube thoracostomy can occasionally be life threatening. Aim. To present an update on the complications and management of complications of tube thoracostomy. Methods. A review of the publications obtained from Medline search, medical libraries, and Google on tube thoracostomy and its complications was done. Results. Tube thoracostomy is a common surgical procedure which can be performed by either the blunt dissection technique or the trocar technique. Complication rates are increased by the trocar technique. These complications have been broadly classified as either technical or infective. Technical causes include tube malposition, blocked drain, chest drain dislodgement, reexpansion pulmonary edema, subcutaneous emphysema, nerve injuries, cardiac and vascular injuries, oesophageal injuries, residual/postextubation pneumothorax, fistulae, tumor recurrence at insertion site, herniation through the site of thoracostomy, chylothorax, and cardiac dysrhythmias. Infective complications include empyema and surgical site infection. Conclusion. Tube thoracostomy, though commonly performed is not without risk. Blunt dissection technique has lower risk of complications and is hence recommended.

Reexpansion pulmonary edema

A reexpanziós tüdőödéma (RPE) egy ritkán előforduló kórállapot, amely rendszerint a krónikusan kollabált tüdő reexpanziója után jelentkezik. A klinikai manifesztáció széles skálán mozog a tünetmentes betegtől a halálos kimenetelig, amely utóbbi akár az esetek 20%-ában is előfordulhat. A patofiziológiai háttér komplex és máig nem teljesen tisztázott. Az ismert kockázati tényezők szem előtt tartásával és azok lehetőség szerinti kiküszöbölésével akár el is kerülhető az RPE kialakulása. Ez az összefoglaló megpróbál áttekintést adni a jelenlegi ismereteinkről, az RPE hátteréről, a terápiás lehetőségekről. Orv. Hetil., 2010,41,1708–1711.

Proanthocyanidin to prevent formation of the reexpansion pulmonary edema

Background

We aimed to investigate the preventive effect of Proanthocyanidine (PC) in the prevention of RPE formation.

Methods

Subjects were divided into four groups each containing 10 rats. In the Control Group (CG): RPE wasn't performed. Then subjects were followed up for three days and they were sacrificed after the follow up period. Samplings were made from tissues for measurement of biochemical and histopathologic parameters. In the Second Group (PCG): The same protocol as CG was applied, except the administration of PC to the subjects. In the third RPE Group (RPEG): Again the same protocol as CG was applied, but as a difference, RPE was performed. In the Treatment Group (TG): The same protocol as RPEG was applied except the administration of PC to the subjects.

Results

In RPEG group, the most important histopathological finding was severe pulmonary edema with alveolar damage and acute inflammatory cells. These findings were less in the TG group. RPE caused increased MDA levels, and decreased GPx, SOD and CAT activity significantly in lung tissue.

Conclusion

PC decreased MDA levels. Oxidative stress plays an important role in pathophysiology of RPE and PC treatment was shown to be useful to prevent formation of RPE.

Protective efficiacy of taurine against pulmonary edema progression: experimental study

Re-expansion pulmonary edema (RPE) is an acute, rare and potentially lethal complication [1,2]. Its beginning is sudden and dramatic. The mechanism is not yet fully understood [1]. Some authors suggest that it may occur after rapid re-inflation of a collapsed lung [1]. It was reported by other authors that it may relate to surfactant depletion or may result from hypoxic capillary damage, leading to increased capillary permeability [1,3]. In RPE, unilateral lung injury is initiated by cytotoxic oxygen metabolites and temporally associated with an influx of polymorphonuclear neutrophils [1]. These toxic oxygen products are the results of re-oxygenation of a collapsed lung. Treatment of re-expansion pulmonary edema is basically preventive [4].

Effects of the time interval between clamping and linear stapling for resection of porcine small intestine

BACKGROUND

Although a wait of several seconds after clamping is recommended when an automatic stapler is used to achieve adequate hemostasis, this wait has not been experimentally clarified.

METHODS

To determine whether waiting is necessary between clamping and firing of a linear stapler, this study evaluated the number of staple line bleeding points and histologic changes in stapling sites of porcine small intestine (n = 46). It also assessed the ratio of dry to wet tissue weight (DW ratio) (n = 20) of porcine small intestine clamped between the prongs of a linear stapler. The sites were studied separately as follows: no wait with a four-row device (n = 12), no wait with a six-row device (n = 11), wait with a four-row device (n = 12), and wait with a six-row device (n = 11). The linear stapler was fired immediately after clamping in the no wait group and 1 min after clamping in the wait group.

RESULTS

The mean number of staple line bleeding points in 2 to 5 min with the six-row device and in 3 to 5 min with the four-row device after firing were significantly less in the wait group than in the no wait group using the same device (p < 0.05). Cross sections of staple lines showed a higher frequency of mucosal cutting in the no wait group than in the wait group for both the four-row and the six-row devices (both significant at p < 0.01). Although the mean wet tissue weights of anastomotic sites did not change in either group, the mean DW ratio was significantly less in the wait group than in the no wait group (p < 0.01).

CONCLUSIONS

A 1-min interval after clamping decreases the amount of clamped tissue. Waiting may thus be necessary to reduce bleeding from stapling sites, which may be related to a decrease in mucosal cutting.

Anti-interleukin 8 autoantibody:interleukin 8 immune complexes visualized by laser confocal microscopy in injured lung

CONTEXT

Anti-interleukin 8 autoantibody:interleukin 8 (anti-IL-8 autoantibody:IL-8) complexes are present in lung fluids of patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS), and levels of these complexes correlate with progression to and the outcome of ARDS. Fc gammaRIIa, an immunoglobulin G (IgG) receptor, mediates proinflammatory activity of the complexes.

OBJECTIVE

To evaluate lung tissues from patients with ARDS for presence of anti-IL-8 autoantibody:IL-8 complexes and to establish whether the complexes associate with Fc gammaRIIa.

DESIGN

Lung tissue sections from 3 patients with ARDS and sections of normal lung tissues from 3 patients were stained with antibodies against IL-8 and IgG to detect immune complexes and with antibody against Fc gammaRIIa. In some experiments, sections were blocked with anti-Fc gamma RIIa antibody before staining. Samples were analyzed using confocal microscopy.

RESULTS

Interleukin 8 costained with IgG and Fc gammaRIIa in lung tissues from patients with ARDS but not in control tissues, suggesting that anti-IL-8 autoantibody:IL-8 complexes are deposited in lungs of patients with ARDS via Fc gammaRIIa. Further, colocalization between IL-8 and Fc gammaRIIa could be blocked by anti-Fc gammaRIIa.

CONCLUSIONS

Our data demonstrate that anti-IL-8 autoantibody:IL-8 complexes are present in lung tissues of patients with ARDS, and are attached to Fc gammaRIIa.

A Novel, Orally Active CXCR1/2 Receptor Antagonist, Sch527123, Inhibits Neutrophil Recruitment, Mucus Production, and Goblet Cell Hyperplasia in Animal Models of Pulmonary Inflammation

Sch527123 [2-hydroxy-N,N-dimethyl-3-[[2-[[1(R)-(5-methyl-2-furanyl)propyl]amino]-3,4-dioxo-1-cyclobuten-1-yl]amino]ben-zamide] is a potent, selective antagonist of the human CXCR1 and CXCR2 receptors (Gonsiorek et al., 2007). Here we describe its pharmacologic properties at rodent CXCR2 and at the CXCR1 and CXCR2 receptors in the cynomolgus monkey, as well as its in vivo activity in models demonstrating prominent pulmonary neutrophilia, goblet cell hyperplasia, and mucus production. Sch527123 bound with high affinity to the CXCR2 receptors of mouse (K(d) = 0.20 nM), rat (K(d) = 0.20 nM), and cynomolgus monkey (K(d) = 0.08 nM) and was a potent antagonist of CXCR2-mediated chemotaxis (IC(50) approximately 3-6 nM). In contrast, Sch527123 bound to cynomolgus CXCR1 with lesser affinity (K(d) = 41 nM) and weakly inhibited cynomolgus CXCR1-mediated chemotaxis (IC(50) approximately 1000 nM). Oral treatment with Sch527123 blocked pulmonary neutrophilia (ED(50) = 1.2 mg/kg) and goblet cell hyperplasia (32-38% inhibition at 1-3 mg/kg) in mice following the intranasal lipopolysaccharide (LPS) administration. In rats, Sch527123 suppressed the pulmonary neutrophilia (ED(50) = 1.8 mg/kg) and increase in bronchoalveolar lavage (BAL) mucin content (ED(50) =<0.1 mg/kg) induced by intratracheal (i.t.) LPS. Sch527123 also suppressed the pulmonary neutrophilia (ED(50) = 1.3 mg/kg), goblet cell hyperplasia (ED(50) = 0.7 mg/kg), and increase in BAL mucin content (ED(50) = <1 mg/kg) in rats after i.t. administration of vanadium pentoxide. In cynomolgus monkeys, Sch527123 reduced the pulmonary neutrophilia induced by repeat bronchoscopy and lavage (ED(50) = 0.3 mg/kg). Therefore, Sch527123 may offer benefit for the treatment of inflammatory lung disorders in which pulmonary neutrophilia and mucus hypersecretion are important components of the underlying disease pathology.

Re-expansion unilateral pulmonary oedema after surgical drainage of a giant hepatic cyst: a case report

Re-expansion pulmonary oedema is an uncommon and potentially life-threatening complication after rapid expansion of a collapsed lung. Symptom onset (cough, chest pain, dyspnoea) is often sudden and the clinical picture may be dramatic. Pathogenesis is complex and partially unclear. A well-timed intensive therapy allows a better prognosis. To date, only one case of re-expansion pulmonary oedema following fenestration of a giant hepatic cyst has been reported in the literature. We here report a new case after surgical fenestration of a giant hepatic cyst.

Local and systemic impacts of pleural oxygen exposure in thoracotomy

The pleural cavity is normally in a state of negative pressure and low oxygen tension. It is exposed to the atmosphere during thoracic surgery. However, no reports of pathophysiological investigation of the effects of pleural oxygen exposure involved in thoracotomy are available. In this study, the effects of pleural oxygen exposure on systemic and pleural inflammation were investigated. Male Wistar rats (9 weeks old) were placed on mechanical ventilation and underwent thoracotomy with lipopolysaccharide (LPS) administration, which simulates latent inflammatory condition. The pleural cavity was exposed to nitrogen (N(2) thoracotomy group), air (20% oxygen, air thoracotomy group), or 100% oxygen (O(2) thoracotomy group) under mechanical ventilation for 2 h. Animals were sacrificed 2 h or 8 h after LPS administration, and inflammatory indices (plasma tumor necrosis factor-alpha and interleukin-6, histology) were examined. For examination of inflammatory mediators, pleural effusion was added to cultured RAW264 cells, a murine macrophage cell line, and tumor necrosis factor-alpha levels in supernatant were measured. The capacity of pleural superoxide generation was investigated without LPS administration. Results showed increases in plasma interleukin-6 concentration and lung injury in the air and O(2) thoracotomy groups. Pleural oxygen exposure stimulated pleural superoxide generation, and increased pleural 4-hydroxy-2-nonenal and lung lipid peroxide concentrations. Tumor necrosis factor-alpha levels in cell culture supernatants were increased by the addition of pleural effusion from the air and O(2) thoracotomy groups. In conclusion, pleural oxygen exposure induced pleural oxidative injury and aggravated latent systemic inflammatory response.

Neutrophil Elastase Inhibitor, Sivelestat, Attenuates Acute Lung Injury After Cardiopulmonary Bypass in the Rabbit Endotoxemia Model

BACKGROUND

Neutrophil elastase probably contributes to the development of acute lung injury after cardiopulmonary bypass (CPB) in patients with infection or shock. We evaluated whether pretreatment with sivelestat sodium hydrate, a neutrophil elastase inhibitor (EI), can prevent acute lung injury caused by CPB.

METHODS

Rabbits were assigned four groups: CPB for 60 minutes, control CPB group; low-dose lipopolysaccharide (LPS) administration without CPB, LPS group; CPB after lipopolysaccharide administration, LPS+CPB group; or preparation with continuous infusion of sivelestat and CPBs after lipopolysaccharide administration, EI group. Blood samples to determine blood gas concentration, plasma elastase activity, and plasma interleukin-8 levels were obtained. Histopathologic examinations of the lung were performed.

RESULTS

The decreased arterial oxygen pressure at the end of CPB was observed in the LPS+CPB group only, but was suppressed in the EI group (p < 0.01). Elastase activity was markedly elevated at 120 minutes after CPB, and interleukin-8 levels were markedly elevated at 180 minutes in the LPS+CPB group but were much lower (p < 0.05) in the EI group. Histopathology demonstrated accumulation of polymorphonuclear neutrophils in bronchoalveolar areas in the LPS+CPB group (p < 0.01). Pulmonary myeloperoxidase activity was significantly lower in the LPS+CPB group than in the other groups (p < 0.01). These changes were minimal in the EI group.

CONCLUSIONS

The combination of low dose LPS+60 minutes of CPB, but neither intervention alone, produced evidence of acute lung injury in a rabbit model. This did not occur when the animals were pretreated with sivelestat.

The effects of oxidative stress on the liver and ileum in rats caused by one-lung ventilation

BACKGROUND AND AIM

Reactive oxygen radicals that cause remote organ injury are increased after the one-lung ventilation frequently used in thoracic surgery. The aim of this study was to examine the effects of one-lung ventilation on the liver and ileum.

MATERIALS AND METHODS

Thirty rats were divided into five groups: a sham group; 3- and 4-h mechanical ventilation groups; and 1- and 2-h left lung collapse/2-h re-expansion groups (n = 6 for each group). In the collapse groups, the left lung was collapsed by bronchial occlusion for 1 and 2 h and then re-expanded and ventilated for an additional 2 h. At the end of the study, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were determined to assess liver functions. Myeloperoxidase (MPO) and malondialdehyde (MDA) activity were determined in the liver and ileum tissues. The tissues were also examined by light and electron microscope. Apoptosis was assessed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) assay.

RESULTS

Plasma ALT and AST, tissue MDA, and MPO activities in both tissues were significantly higher in the 2-h collapse/2-h re-expansion group than in the 4-h mechanical ventilation group (P < 0.05). Moreover, the levels were significantly higher in the 2-h collapse group compared to the 1-h collapse group (P < 0.016). Tissue damage and apoptotic index were most prominent in the 2-h collapse/2-h re-expansion group.

CONCLUSION

Our findings showed that one-lung ventilation causes tissue damage in the liver and ileum and that this damage increases as occlusion duration rises.

Role of Rho-kinase in reexpansion pulmonary edema in rabbits

Reexpansion of a collapsed lung increases the microvascular permeability and causes reexpansion pulmonary edema. Neutrophils and their products have been implicated in the development of this phenomenon. The small GTP-binding proteins Rho and its target Rho-kinase (ROCK) regulate endothelial permeability, although their roles in reexpansion pulmonary edema remain unclear. We studied the contribution of ROCK to pulmonary endothelial and epithelial permeability in a rabbit model of this disorder. Endothelial and epithelial permeability was assessed by measuring the tissue-to-plasma (T/P) and bronchoalveolar lavage (BAL) fluid-to-plasma (B/P) ratios with (125)I-labeled albumin. After intratracheal instillation of (125)I-albumin, epithelial permeability was also assessed from the plasma leak (PL) index, the ratio of (125)I-albumin in plasma/total amount of instilled (125)I-albumin. T/P, B/P, and PL index were significantly increased in the reexpanded lung. These increases were attenuated by pretreatment with Y-27632, a specific ROCK inhibitor. However, neutrophil influx, neutrophil elastase activity, and malondialdehyde concentrations in BAL fluid collected from the reexpanded lung were not changed by Y-27632. In endothelial monolayers, Y-27632 significantly attenuated the H(2)O(2)-induced increase in permeability and mitigated the morphological changes in the actin microfilament cytoskeleton of endothelial cells. These in vivo and in vitro observations suggest that the Rho/ROCK pathway contributes to the increase in alveolar barrier permeability associated with reexpansion pulmonary edema.

Benzamil, a blocker of epithelial Na(+) channel-induced upregulation of artery oxygen pressure level in acute lung injury rabbit ventilated with high frequency oscillation

The epithelial Na(+) transport via an epithelial Na(+) channel (ENaC) expressed in the lung epithelium would play a key role in recovery from lung edema at acute lung injury by removing the fluid in lung luminal space. The lung edema causes dysfunction of gas exchange, decreasing oxygen pressure level of artery [P(aO(2))]. To study if ENaC plays a key role in recovering P(aO(2)) from a decreased level to a normal one in acute lung injury, we applied benzamil (20microM, a specific blocker of ENaC) to the lung luminal space in acute lung injury treated with high frequency oscillation ventilation (HFOV) that is a lung-protective ventilation with a lower tidal volume and a smaller pressure swing than conventional mechanical ventilation (CMV). Benzamil facilitated the recovery of P(aO(2)) in acutely injured lung with HFOV but not CMV. The observation suggests that in acutely injured lung treated with HFOV an ENaC blocker, benzamil, can be applied as a therapeutic drug for acute lung injury combing with HFOV.

Topical interleukin-8 antibody attracts leukocytes in a piglet lavage model

OBJECTIVE

Acute respiratory distress syndrome (ARDS) in young infants is linked with a pulmonary inflammatory response part of which are increased interleukin-8 (IL-8) levels and migration of polymorphonuclear leukocytes (PMNL) into lung tissue. A topical application of an antibody against IL-8 might therefore decrease PMNL migration and improve lung function.

DESIGN

Randomized, controlled, prospective animal study.

SETTING

Research laboratory of a university children's hospital.

SUBJECTS AND INTERVENTIONS

Anesthetized, mechanically ventilated newborn piglets (n=22) underwent repeated airway lavage to remove surfactant and to induce lung inflammation. Piglets then received either surfactant alone (S, n=8), or a topical antibody against IL-8 admixed to surfactant (S+IL-8, n=8), or an air bolus injection (control, n=6).

MEASUREMENTS AND RESULTS

After 6 h of mechanical ventilation following intervention, oxygenation [S 169+/-51 (SD) vs S+IL-8 139+/-61 mmHg] and lung function (compliance: S 1.3+/-0.4 vs S+IL-8 0.9+/-0.4 ml/cmH(2)O/kg; extra-vascular lung-water: S 27+/-9 vs S+IL-8 52+/-28 ml/kg) were worse in the S+IL-8 group because reactive IL-8 production [S 810 (median, range 447-2323] vs S+IL-8 3485 (628-16180) pg/ml; P<0.05) with facilitated migration of PMNL into lung tissue occurred. Moreover, antibody application caused augmented chemotactic potency of IL-8 [linear regression of migrated PMNL and IL-8 levels: S r(2)=0.30 (P=ns) vs S+IL-8 r(2)=0.89 (P=0.0002)].

CONCLUSION

Topical anti-IL-8 treatment after lung injury increases IL-8 production, PMNL migration, and worsens lung function in our piglet lavage model. This effect is in contrast to current literature using pre-lung injury treatment protocols. Our data do not support anti-IL-8 treatment in young infants with ARDS.

Alveolar and plasma concentrations of interleukin-8 and vascular endothelial growth factor following oesophagectomy

The acute respiratory distress syndrome occurs in approximately 10% of all patients undergoing elective oesophagectomy. Local increases in lung pro-inflammatory cytokines have been previously detected in high-risk patients before the development of the acute respiratory distress syndrome. We hypothesised that similar changes would occur following oesophagectomy. Two groups of patients were studied. In the collapsed lung group (n = 11), interelukin-8 and vascular endothelial growth factor were measured in bronchoalveolar lavage samples obtained from the intra-operative collapsed lung after operation. In the ventilated lung group (n = 10), bronchoalveolar lavage was performed after operation from the ventilated lung and cytokines measured. Cytokines were also measured in peripheral blood samples before and after operation. Bronchoalveolar lavage cytokine levels in both lungs were of an order of magnitude greater than in peripheral blood. Pulmonary pro-inflammatory cytokine release occurs following oesophageal surgery and may indicate subclinical lung injury.

Hydrostatic mechanisms may contribute to the pathogenesis of human re-expansion pulmonary edema

OBJECTIVE

The primary objective was to test the hypothesis that clinical re-expansion pulmonary edema is predominantly due to increased permeability of the alveolar-capillary barrier. A secondary objective was to determine if the alveolar epithelium was functionally intact in patients with re-expansion pulmonary edema by measuring net alveolar epithelial fluid transport in a subset of patients.

DESIGN

Retrospective study of mechanically ventilated patients with re-expansion pulmonary edema.

SETTING

Two academic tertiary care hospitals.

PATIENTS

Seven patients with acute onset of re-expansion pulmonary edema after tube thoracostomy or thoracentesis.

INTERVENTIONS

Pulmonary edema fluid and plasma were collected at the time of onset of re-expansion edema.

MEASUREMENTS AND RESULTS

Contrary to our hypothesis, the mean initial edema fluid to plasma protein ratio was 0.58+/-0.21, supporting a hydrostatic mechanism of edema formation. Four of the patients had an initial edema fluid to plasma protein ratio of less than 0.65, consistent with pure hydrostatic pulmonary edema, while the others had a slight increase in permeability (edema fluid to plasma ratios of 0.67, 0.71 and 0.77), perhaps due to capillary stress failure from hydrostatic stress. Alveolar fluid clearance (mean 9.8+/-8.0%/h) was intact in the subset of three patients in whom it was measured.

CONCLUSIONS

This study provides the first direct evidence that hydrostatic forces may contribute to the development of re-expansion pulmonary edema.

Effect of re-expansion after short-period lung collapse on pulmonary capillary permeability and pro-inflammatory cytokine gene expression in isolated rabbit lungs

BACKGROUND

Re-expansion pulmonary oedema is a rare complication caused by rapid re-expansion of a chronically collapsed lung. Several cases of pulmonary oedema associated with one-lung ventilation (OLV) have been reported recently. Elevated levels of pro-inflammatory cytokines in pulmonary oedema fluid are suggested to play important roles in its development. Activation of cytokines after re-expansion of collapsed lung during OLV has not been thoroughly investigated. Here we investigated the effects of re-expansion of the collapsed lung on pulmonary oedema formation and pro-inflammatory cytokine expression.

METHODS

Lungs isolated from female white Japanese rabbits were perfused and divided into a basal (BAS) group (n=7, baseline measurement alone), a control (CONT) group (n=9, ventilated without lung collapse for 120 min) and an atelectasis (ATEL) group (n=9, lung collapsed for 55 min followed by re-expansion and ventilation for 65 min). Pulmonary vascular resistance (PVR) and the coefficient of filtration (Kfc) were measured at baseline and 60 and 120 min. At the end of perfusion, bronchoalveolar lavage fluid/plasma protein ratio (B/P), wet/dry lung weight ratio (W/D) and mRNA expressions of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and myeloperoxidase (MPO) were determined.

RESULTS

TNF-alpha and IL-1beta mRNA were significantly up-regulated in lungs of the ATEL group compared with BAS and CONT, though no significant differences were noted in PVR, Kfc, B/P and W/D within and between groups. MPO increased at 120 min in CONT and ATEL groups.

CONCLUSION

Pro-inflammatory cytokines were up-regulated upon re-expansion and ventilation after short-period lung collapse, though no changes were noted in pulmonary capillary permeability.

Flow cytometric detection of cell-associated interleukin-8 in alveolar macrophages in vivo from patients with hypersensitivity pneumonitis and sarcoidosis

In comparison with neutrophil-mediated lung diseases, such as acute respiratory distress syndrome, the involvement of IL-8 in lymphocyte-mediated lung diseases has not been fully investigated. Several reports have shown a slight increase in bronchoalveolar lavage fluid (BALF) IL-8 in patients with hypersensitivity pneumonitis (HP) and sarcoidosis (SAR), but the source of the IL-8 has not been clarified. In the present study, the in vivo production of IL-8 by alveolar macrophages (AMs) is examined in these patients by analyzing the cell-associated IL-8, using the flow cytometric method adopted previously. The IL-8 levels in the epithelial lining fluid (ELF) were also assessed. Initially, slight, but significant, increased levels of ELF IL-8 in HP and SAR were confirmed. Using flow cytometric analysis, a significant increase was found in the cell-associated IL-8 of the freshly isolated AMs in HP, but not in SAR, indicating in vivo production of IL-8 by AMs in HP. The cell-associated IL-8 of the AMs cultured with or without lipopolysaccharide was also analyzed. However, in contrast to previous findings in patients with idiopathic pulmonary fibrosis, no differences were found between SAR and HP patients and control subjects. Based on these findings, it is speculated that ELF IL-8 levels are slightly increased in HP and SAR, and they may contribute to the accumulation of neutrophils and possibly lymphocytes. However, the source of IL-8 may be different and AMs are the candidate source of IL-8 in HP, but not in SAR. The flow cytometric method may be useful in assessing cytokines production by AMs.

Airway obstruction in sheep with burn and smoke inhalation injuries

The goals of this study were (i) to compare the degree and (ii) temporal changes in airway obstruction in sheep with pulmonary injury induced by smoke inhalation and/or burn; (iii) to qualitatively assess the cellular and mucous content of obstructive material; and (iv) to statistically assess a possible relationship between the degree of airway obstruction and pulmonary dysfunction. Using masked histologic slides, we estimated the degree of luminal obstruction in all cross-sectioned airways. The mean degree of bronchial, bronchiolar, and terminal bronchiolar obstruction was significantly greater in animals with smoke injury alone or combined smoke inhalation and burn (S+B) injury, compared with animals with burn injury alone or uninjured animals (P < 0.05). In S+B animals, the degree of bronchial obstruction was maximal at 24 h, with a progressive decrease over 72 h. In contrast, the degree of bronchiolar obstruction increased over time. Qualitatively, bronchial casts were largely composed of mucus at early times after injury, whereas neutrophils were the principal component of bronchiolar obstructive material. Localization of specific mucin subtypes in S+B tissues suggests that increasing bronchiolar obstruction is derived, in part, from upper airway material. Multiple linear regression analysis of airway obstruction scores compared with PaO2/FIO2 values showed a correlation coefficient of r = 0.76, with bronchial and bronchiolar scores predictive of PaO2/FIO2, (P < 0.05). These results suggest that strategies to remove or decrease formation of upper airway obstructive material may reduce its deposition into small airways and parenchyma and may improve respiratory function in victims of smoke inhalation injury.

Gene expression analysis in interstitial lung edema induced by saline infusion

To investigate the molecular events taking place during the development of hydraulic interstitial edema, we analyzed by microarray and conventional molecular techniques the variation of gene expression in lung from rabbits treated with slow-rate saline infusions. This analysis indicates that even a condition characterized by a small increase in extravascular water can have a significant influence on the inflammatory milieu. In this regard, cytokines, in particular TNFalpha, can be considered early mediators capable of inducing secondary effects on the injured tissue. Moreover, two MT1 genes were strongly up-regulated, data consistent with their role as protective molecules.

Pathophysiological roles of interleukin-8/CXCL8 in pulmonary diseases

Fifteen years have passed since the first description of interleukin (IL)-8/CXCL8 as a potent neutrophil chemotactic factor. Accumulating evidence has demonstrated that various types of cells can produce a large amount of IL-8/CXCL8 in response to a wide variety of stimuli, including proinflammatory cytokines, microbes and their products, and environmental changes such as hypoxia, reperfusion, and hyperoxia. Numerous observations have established IL-8/CXCL8 as a key mediator in neutrophil-mediated acute inflammation due to its potent actions on neutrophils. However, several lines of evidence indicate that IL-8/CXCL8 has a wide range of actions on various types of cells, including lymphocytes, monocytes, endothelial cells, and fibroblasts, besides neutrophils. The discovery of these biological functions suggests that IL-8/CXCL8 has crucial roles in various pathological conditions such as chronic inflammation and cancer. Here, an overview of its protein structure, mechanisms of production, and receptor system will be discussed as well as the pathophysiological roles of IL-8/CXCL8 in various types of lung pathologies.

Reexpansion pulmonary edema

Reexpansion pulmonary edema (RPE) is a rare, but frequently lethal, clinical condition. The precise pathophysiologic abnormalities associated with this disorder are still unknown, though decreased pulmonary surfactant levels and a pro-inflammatory status are putative mechanisms. Early diagnosis is crucial, since prognosis depends on early recognition and prompt treatment. Considering the high mortality rates related to RPE, preventive measures are still the best available strategy for patient handling. This review provides a brief overview of the pathophysiology, diagnosis, treatment, and prevention of RPE, with practical recommendations for adequate intervention.

Prior burn insult induces lethal acute lung injury in endotoxemic mice: effects of cytokine inhibition

Many patients who experience surgical stress, including burn injury, become susceptible to severe sepsis and septic organ dysfunction, which remains the primary contributor to morbidity and mortality in burn patients. In the present study, we developed a murine model of burn-primed sublethal endotoxemia by producing a 15% BSA full-thickness burn on the dorsum of BALB/c mice under ether anesthesia and administering 10 mg/kg of LPS intravenously on day 11 to model endotoxemia. The prior burn injury in this model induced two-peaked production of cytokines, TNF-alpha, and macrophage inflammatory protein-2 at 2 and 12 h after LPS administration, and it was associated with increased mortality. We also assessed the effect of pharmacological modulation with cytokine synthesis inhibitors prednisolone and JTE-607 and found that pretreatment with them attenuated later cytokine production and decreased mortality after LPS administration. We speculate that the prior burn injury primed the mice for the secondary insult via cytokine production. These results also suggested that an anticytokine strategy might serve as a novel prophylactic therapy for septic organ dysfunction in burn-primed patients.

Reexpansion pulmonary edema: a case report and review of the current literature

This case report illustrates the presentation and course of reexpansion pulmonary edema (REPE) in a young man with spontaneous pneumothorax. REPE is considered relatively uncommon by most accounts, but in certain clinical circumstances the incidence is much higher. Although supportive therapy is the rule, the condition is far from benign and mortality estimates are as high as 20%. Risk factors, including young age, a large pneumothorax and longer duration of collapse, may help predict which patient will encounter this complication. In patients with these risk factors, the thoracostomy tube should be initially left off suction in an effort to prevent REPE primarily. When REPE is encountered, therapy is supportive.

Characterization of a murine model of endotoxin-induced acute lung injury

Endotoxin-induced microvascular lung injury in mice is a commonly used experimental model of the acute respiratory distress syndrome (ARDS). The present paper aimed to characterize this popular model in a comprehensive and systematic fashion. Male C57bl/6 mice (n = 5) were administered an LD55 dose of E. coli endotoxin (15 mg/kg, i.p.), and lungs were harvested at several time points and evaluated for injury as well as for expression of a variety of inflammatory mediators. Endotoxin induced many features characteristic of acute microvascular lung injury. These included early (1-2 h) expression of inflammatory mediators (IL-1alpha, IL-1beta, IL-4, IL-6, IL-10, TNF-alpha, interferon-alpha, interferon gamma, and MCP-1) and leukocyte accumulation in lung tissue (lung myeloperoxidase activity 18.5 +/- 7.8 U/g tissue, P < 0.05), followed by pulmonary edema (lung water content index 17.4% +/- 2.5%, P < 0.05) and mortality. Histopathological evaluation of lung tissue was compatible with these findings. The characterization of this murine model of endotoxin-induced microvascular injury will facilitate its utilization in ARDS research.

Adapting pharmacokinetic properties of a humanized anti-interleukin-8 antibody for therapeutic applications using site-specific pegylation

A neutralizing anti-interleukin-(IL-)8 monoclonal antibody was humanized by grafting the complementary determining regions onto the human IgG framework. Subsequent alanine scanning mutagenesis and phage display enabled the production of an affinity matured antibody with a >100-fold improvement in IL-8 binding. Antibody fragments can be efficiently produced in Escherichia coli but have the limitation of rapid clearance rates in vivo. The Fab' fragment of the antibody was therefore modified with polyethylene glycol (PEG) in order to obtain a more desirable pharmacokinetic profile. PEG (5-40 kDa) was site-specifically conjugated to the Fab' via the single free cysteine residue in the hinge region. In vitro binding and bioassays showed little or no loss of activity. The pharmacokinetic profiles of the 20 kDa, 30 kDa, 40 kDa, and 40 kDa branched PEG-Fab' molecules were evaluated in rabbits. Relative to the native Fab', the clearance rates of the PEGylated molecules were decreased by 44-175-fold. In a rabbit ear model of ischemia/reperfusion injury, all PEGylated Fab' molecules were as efficacious in reducing oedema as the original monoclonal antibody. These studies demonstrate that it is possible to customize the pharmacokinetic properties of a Fab' while retaining its antigen binding activity.

Interleukin-8 receptor antagonists in pulmonary diseases

Inflammatory cells are thought to be instrumental in the pathophysiology of pulmonary diseases, and control of their recruitment and activation in the lung would appear to be an attractive strategy for therapeutic intervention. Interleukin-8 and related CXC chemokines are involved in the function of neutrophils and T cells, and have been implicated in several lung diseases. Small-molecule antagonists of the interleukin-8 receptors have been identified, which may help elucidate the role of interleukin-8 and related chemokines in the pathophysiology of lung diseases.