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

Proteomics of lung tissue reveals differences in inflammation and alveolar-capillary barrier response between atelectasis and aerated regions

Atelectasis is a frequent clinical condition, yet knowledge is limited and controversial on its biological contribution towards lung injury. We assessed the regional proteomics of atelectatic versus normally-aerated lung tissue to test the hypothesis that immune and alveolar-capillary barrier functions are compromised by purely atelectasis and dysregulated by additional systemic inflammation (lipopolysaccharide, LPS). Without LPS, 130 proteins were differentially abundant in atelectasis versus aerated lung, mostly (n = 126) with less abundance together with negatively enriched processes in immune, endothelial and epithelial function, and Hippo signaling pathway. Instead, LPS-exposed atelectasis produced 174 differentially abundant proteins, mostly (n = 108) increased including acute lung injury marker RAGE and chemokine CCL5. Functional analysis indicated enhanced leukocyte processes and negatively enriched cell-matrix adhesion and cell junction assembly with LPS. Additionally, extracellular matrix organization and TGF-β signaling were negatively enriched in atelectasis with decreased adhesive glycoprotein THBS1 regardless of LPS. Concordance of a subset of transcriptomics and proteomics revealed overlap of leukocyte-related gene-protein pairs and processes. Together, proteomics of exclusively atelectasis indicates decreased immune response, which converts into an increased response with LPS. Alveolar-capillary barrier function-related proteomics response is down-regulated in atelectasis irrespective of LPS. Specific proteomics signatures suggest biological mechanistic and therapeutic targets for atelectasis-associated lung injury.

Pulmonary levels of biomarkers for inflammation and lung injury in protective versus conventional one-lung ventilation for oesophagectomy: A randomised clinical trial

BACKGROUND

It is uncertain whether protective ventilation reduces ventilation-induced pulmonary inflammation and injury during one-lung ventilation.

OBJECTIVE

To compare intra-operative protective ventilation with conventional during oesophagectomy with respect to pulmonary levels of biomarkers for inflammation and lung injury.

DESIGN

Randomised clinical trial.

SETTING

Tertiary centre for oesophageal diseases.

PATIENTS

Twenty-nine patients scheduled for one-lung ventilation during oesophagectomy.

INTERVENTIONS

Low tidal volume (VT) of 6 ml kg predicted body weight (pbw) during two-lung ventilation and 3 ml kgpbw during one-lung ventilation with 5 cmH2O positive end expired pressure versus intermediate VT of 10 ml kgpbw during two-lung ventilation and 5 ml kgpbw body weight during one-lung ventilation with no positive end-expiratory pressure.

OUTCOME MEASURES

The primary outcome was the change in bronchoalveolar lavage (BAL) levels of preselected biomarkers for inflammation (TNF-α, IL-6 and IL-8) and lung injury (soluble Receptor for Advanced Glycation End-products, surfactant protein-D, Clara Cell protein 16 and Krebs von den Lungen 6), from start to end of ventilation.

RESULTS

Median [IQR] VT in the protective ventilation group (n = 13) was 6.0 [5.7 to 7.8] and 3.1 [3.0 to 3.6] ml kgpbw during two and one-lung ventilation; VT in the conventional ventilation group (n = 16) was 9.8 [7.0 to 10.1] and 5.2 [5.0 to 5.5] ml kgpbw during two and one-lung ventilation. BAL levels of biomarkers for inflammation increased from start to end of ventilation in both groups; levels of soluble Receptor for Advanced Glycation End-products, Clara Cell protein 16 and Krebs von den Lungen 6 did not change, while levels of surfactant protein-D decreased. Changes in BAL biomarkers levels were not significantly different between the two ventilation strategies.

CONCLUSION

Intra-operative protective ventilation compared with conventional ventilation does not affect changes in pulmonary levels of biomarkers for inflammation and lung injury in patients undergoing one-lung ventilation for oesophagectomy.

TRIAL REGISTRATION

The 'Low versus Conventional tidal volumes during one-lung ventilation for minimally invasive oesophagectomy trial' (LoCo) was registered at the Netherlands Trial Register (study identifier NTR 4391).

Protective effects of continuous positive airway pressure on a nonventilated lung during one-lung ventilation: A prospective laboratory study in rats

BACKGROUND

The use of one-lung ventilation (OLV) to facilitate intrathoracic surgery is a cause of lung injury.

OBJECTIVE

We hypothesised that application of continuous positive airway pressure (CPAP) to a nonventilated lung during OLV would prevent alveolar hypoxia and blood flow shift from the nonventilated to the ventilated lung, thereby attenuating lung injury.

DESIGN

Controlled animal study.

SETTINGS

University laboratory.

STUDY PARTICIPANTS

Adult male Sprague-Dawley rats (n = 4 to 8 per group, depending on experiments).

INTERVENTIONS

Rats were alternately assigned to one of two ventilation protocol groups: control and CPAP groups. Rats received 240 min of OLV followed by 240 min of two-lung reventilation (re-TLV). The nonventilated lungs of rats in the control group were collapsed during OLV whereas rats in the CPAP group received CPAP (5 cmH2O with 100% oxygen) to the nonventilated lungs.

MAIN OUTCOME MEASURES

Pulmonary blood flow during OLV was measured by quantification of lung radioactivity after intravenous infusion of indium-labelled macroaggregated albumin. Inflammatory cytokines in the lungs after 240 min of OLV, and after the subsequent 240 min of re-TLV were measured. Additionally, we measured lung wet-to-dry weight ratios after re-TLV. We also measured lung malondialdehyde levels after re-TLV as an indicator of reactive oxygen species produced by reoxygenation.

RESULTS

Application of CPAP attenuated the pulmonary blood flow shift from the nonventilated to the ventilated lung. CPAP decreased the levels of IL-6, CXC chemokine ligand-1 and CC chemokine ligand-2 in both lungs after 240 min of OLV. CPAP also decreased CXC chemokine ligand-1 in the nonventilated lung and CC chemokine ligand-2 in both lungs after re-TLV. Moreover, wet-to-dry weight ratios of both lungs were decreased by application of CPAP. However, lung malondialdehyde concentrations were not affected by CPAP.

CONCLUSIONS

CPAP applied to the nonventilated lung during OLV suppresses blood flow shift and decreases inflammatory cytokines and water content in both lungs. Application of CPAP may attenuate lung injury during and after OLV.

Targeted delivery of human iPS-ECs overexpressing IL-8 receptors inhibits neointimal and inflammatory responses to vascular injury in the rat

Interleukin-8 (IL8) is highly expressed by injured arteries in a variety of diseases and is a chemoattractant for neutrophils which express IL8 receptors IL8RA and RB (IL8RA/B) on their membranes. Neutrophils interact with the damaged endothelium and initiate an inflammatory cascade at the site of injury. We have generated a novel translational targeted cell therapy for acute vascular injury using adenoviral vectors to overexpress IL8RA/B and green fluorescent protein (GFP) on the surface of endothelial cells (ECs) derived from human induced pluripotent stem cells (HiPS-IL8RA/B-ECs). We hypothesize that HiPS-IL8RA/B-ECs transfused intravenously into rats with balloon injury of the carotid artery will target to the injured site and compete with neutrophils, thus inhibiting inflammation and neointima formation. Young adult male Sprague-Dawley rats underwent balloon injury of the right carotid artery and received intravenous transfusion of saline vehicle, 1.5 × 10(6) HiPS-ECs, 1.5 × 10(6) HiPS-Null-ECs, or 1.5 × 10(6) HiPS-IL8RA/B-ECs immediately after endoluminal injury. Tissue distribution of HiPS-IL8RA/B-ECs was analyzed by a novel GFP DNA qPCR method. Cytokine and chemokine expression and leukocyte infiltration were measured in injured and uninjured arteries at 24 h postinjury by ELISA and immunohistochemistry, respectively. Neointimal, medial areas, and reendothelialization were measured 14 days postinjury. HiPS-IL8RA/B-ECs homed to injured arteries, inhibited inflammatory mediator expression and inflammatory cell infiltration, accelerated reendothelialization, and attenuated neointima formation after endoluminal injury while control HiPS-ECs and HiPS-Null-ECs did not. HiPS-IL8RA/B-ECs transfused into rats with endoluminal carotid artery injury target to the injured artery and provide a novel strategy to treat vascular injury.

Lung Injury After One-Lung Ventilation: A Review of the Pathophysiologic Mechanisms Affecting the Ventilated and the Collapsed Lung

Lung injury is the leading cause of death after thoracic surgery. Initially recognized after pneumonectomy, it has since been described after any period of 1-lung ventilation (OLV), even in the absence of lung resection. Overhydration and high tidal volumes were thought to be responsible at various points; however, it is now recognized that the pathophysiology is more complex and multifactorial. All causative mechanisms known to trigger ventilator-induced lung injury have been described in the OLV setting. The ventilated lung is exposed to high strain secondary to large, nonphysiologic tidal volumes and loss of the normal functional residual capacity. In addition, the ventilated lung experiences oxidative stress, as well as capillary shear stress because of hyperperfusion. Surgical manipulation and/or resection of the collapsed lung may induce lung injury. Re-expansion of the collapsed lung at the conclusion of OLV invariably induces duration-dependent, ischemia-reperfusion injury. Inflammatory cytokines are released in response to localized injury and may promote local and contralateral lung injury. Protective ventilation and volatile anesthesia lessen the degree of injury; however, increases in biochemical and histologic markers of lung injury appear unavoidable. The endothelial glycocalyx may represent a common pathway for lung injury creation during OLV, because it is damaged by most of the recognized lung injurious mechanisms. Experimental therapies to stabilize the endothelial glycocalyx may afford the ability to reduce lung injury in the future. In the interim, protective ventilation with tidal volumes of 4 to 5 mL/kg predicted body weight, positive end-expiratory pressure of 5 to 10 cm H2O, and routine lung recruitment should be used during OLV in an attempt to minimize harmful lung stress and strain. Additional strategies to reduce lung injury include routine volatile anesthesia and efforts to minimize OLV duration and hyperoxia.

Cytokine & chemokine response in the lungs, pleural fluid and serum in thoracic surgery using one-lung ventilation

Background

Thoracic surgery mandates usually a one-lung ventilation (OLV) strategy with the collapse of the operated lung and ventilation of the non-operated lung. These procedures trigger a substantial inflammatory response. The aim of this study was to analyze the cytokine and chemokine reaction in both lungs, pleural space and blood in patients undergoing lung resection with OLV with special interest in the chemokine growth-regulated peptide alpha (GROα) which is the human equivalent to the rat cytokine-induced neutrophil chemoattractant-1 (CINC-1).

Methods

Broncho-alveolar lavage (BAL) fluid of both the collapsed, operated and the ventilated, non-operated lung, respectively, pleural space drainage fluid and blood was collected and the concentrations of interleukin (IL)-6, IL-1RA and GROα were determined with enzyme-linked immunosorbent assays in 15 patients.

Results

Substantial inter-individual differences in the BAL fluid between patients in cytokine and chemokine levels occurred. In the pleural fluid and the blood these inter-individual differences were less pronounced. Both sides of the lung were affected and showed a significant increase in IL-6 and IL-1RA concentrations over time but not in GROα concentrations. Except for IL-6, which increased more in the collapsed, operated lung, no difference between the collapsed, operated and the ventilated, non-operated lung occurred. In the blood, IL-6 and IL-1RA increased early, already at the end of surgery. GROα was not detectable. In the pleural fluid, both cytokine and chemokine concentrations increased by day one. The increase was significantly higher in the pleural fluid compared to the blood.

Conclusion

The inflammatory response of cytokines affects both the collapsed, operated and the ventilated, non-operated lungs. The difference in extent of response underlines the complexity of the inflammatory processes during OLV. In contrast to the cytokines, the chemokine GROα concentrations did not react in the BAL fluid or in the blood. This indicates that GROα might not be useful as marker for the inflammatory reaction in complex surgical procedures.

Perioperative anesthetic management for esophagectomy

Esophageal resection is a formidable operation associated with high morbidity and mortality. Anesthetic management may contribute to the containment of respiratory failure and anastomotic leakage by the use of thoracic epidural analgesia, protective ventilation strategies, prevention of tracheal aspiration, and judicious fluid management.

Acute lung injury following an esophagectomy for esophageal cancer, with special reference to the clinical factors and cytokine levels of peripheral blood and pleural drainage fluid

Acute lung injury (ALI) is one of most serious complications to occur after an esophagectomy for esophageal cancer. However, the pathogenesis of ALI is still unclear. The cytokine levels of pleural drainage fluid as well as peripheral blood were measured in 27 patients who had undergone an extended radical esophagectomy. Both the clinical factors and cytokine levels were compared between 11 patients with (group I) and 16 without ALI (group II). ALI occurred more frequently in patients who underwent colon interposition than in those who received a gastric tube reconstruction (86%vs 25%, P = 0.009). The operation time of group I was significantly longer than that of group II. A logistic regression analysis revealed colon interposition to be an independent factor associated with the ALI (P < 0.05). Postoperative anastomotic leakage and systemic inflammatory response syndrome (SIRS) occurred more frequently in group I than in group II (P < 0.01). Both the serum interleukin-6 (IL-6) and IL-8 levels of group I were significantly higher than those of group II. IL-1beta and tumor necrosis factor-alpha were undetectable in the peripheral blood, whereas they were detectable in the pleural effusion. The IL-1beta of pleural effusion was higher in group I than group II. In conclusion, greater surgical stress, such as a longer operative time, is thus considered to be associated with the first attack of ALI. The adverse events developing in the extra-thoracic site, such as necrosis and local infection around anastomosis may therefore be the second attack. Furthermore, ALI may cause not only SIRS but also other complications such as anastomotic leakage.

Lung injury after thoracic surgery and one-lung ventilation

PURPOSE OF REVIEW

An update is provided for anaesthetists, on recent work investigating the incidence and cause of lung injury following thoracic surgery. Pulmonary damage is also discussed in relation to the management of one-lung ventilation.

RECENT FINDINGS

The extent of recent original literature on lung injury, following thoracic surgery, is limited for the review period (2004-2005). Increasing evidence that pulmonary oxidative stress and an increase in proinflammatory cytokines are significant contributors to lung injury following thoracic surgery, however, exists. This is particularly the case in patients with lung or oesophageal carcinoma. Animal experiments confirm the above and also indicate that anaesthetic agents may offer some protection against the ischaemia-reperfusion injury sustained as a result of one-lung ventilation.

SUMMARY

Pulmonary damage in the form of acute lung injury and adult respiratory distress syndrome is a major cause of morbidity and mortality after thoracic surgery. An understanding of the pathogenesis of lung damage, following thoracic surgery, may enable anaesthetists to modify this process and decrease the incidence and severity of the problem.