Role of pulmonary artery reactivity and nitric oxide in injury and inflammation following lung contusion

Perioperative Exhaled Nitric Oxide as an Indicator for Postoperative Pneumonia in Surgical Lung Cancer Patients: A Prospective Cohort Study Based on 183 Cases

Introduction

This study is conducted to investigate the correlation between perioperative fractional exhaled nitric oxide and postoperative pneumonia (POP) and the feasibility of perioperative FeNO for predicting POP in surgical lung cancer patients.

Methods

Patients who were diagnosed with non-small-cell lung cancer (NSCLC) were prospectively analyzed, and the relationship between perioperative FeNO and POP was evaluated based on patients' basic characteristics and clinical data in the hospital.

Results

There were 218 patients enrolled in this study. Finally, 183 patients were involved in the study, with 19 of them in the POP group and 164 in the non-POP group. The POP group had significantly higher postoperative FeNO (median: 30.0 vs. 19.0 ppb, P < 0.001) as well as change in FeNO (median: 10.0 vs. 0.0 ppb, P < 0.001) before and after the surgery. For predicting POP based on the receiver operating characteristic (ROC) curve, a cutoff value of 25 ppb for postoperative FeNO (Youden's index: 0.515, sensitivity: 78.9%, and specificity: 72.6%) and 4 ppb for change in FeNO (Youden's index: 0.610, sensitivity: 84.2%, specificity: 76.8%) were selected. Furthermore, according to the bivariate regression analysis, FEV1/FVC (OR = 0.948, 95% CI: 0.899–0.999, P=0.048), POD1 FeNO (OR = 1.048, 95% CI: 1.019–1.077, P=0.001), and change in FeNO (OR = 1.087, 95% CI: 1.044–1.132, P < 0.001) were significantly associated with occurrence of POP.

Conclusions

This prospective study revealed that a high postoperative FeNO (>25 ppb), as well as an increased change in FeNO (>4 ppb), may have the potential in detecting the occurrence of POP in surgical lung cancer patients.

Lungs from polytrauma donors with significant chest trauma can be safely used for transplantation

BACKGROUND

The use of organs from polytrauma donors for lung transplantation is controversial in the literature. For many centers, the radiologic manifestation of lung contusions is a clear reason to reject an organ offer. This results in the loss of potentially viable organs for the donor pool.

METHODS

We analyzed 1152 donor lungs procured by our transplant center between January 2010 and June 2018. These included 118 lungs with a history of polytrauma involving the chest. Sixteen polytrauma donor lungs were rejected after procurement. A total of 102 lungs were transplanted, divided into 2 groups: the polytrauma contusion group (n = 44), comprising polytrauma donors with radiologic signs of lung contusion at the time of offer, and the polytrauma clear group (n = 58), comprising polytrauma donors without lung contusion. Nontrauma donor lungs transplanted during the study period were assigned to a polytrauma control group (n = 650). Short- and long-term outcomes of the 3 groups were compared.

RESULTS

Basic demographic data and preoperative factors were similar in the 3 groups. Rates of primary graft dysfunction grade 3 at 72 hours did not differ among the 3 groups (0.0% vs 3.4% vs 3.9%; P = .409). The duration of ventilation was similar the 3 groups: 45 hours (interquartile range [IQR], 28-94 hours), 37 hours (IQR, 22-71 hours), and 42 hours (IQR, 22-96 hours), respectively (P = .674). Long-term graft survival was not impaired in the trauma groups compared with controls. One-year survival rates were 84.1% for the polytrauma contusion group, 93.1% for the polytrauma clear group, and 83.1% for the no polytrauma group. Five-year graft survival in the 3 groups was 74.7%, 87.2%, and 70.0%, respectively.

CONCLUSIONS

Lung transplantation using organs from polytrauma donors is associated with similar short- and long-term results as transplantation from nontrauma donors. The presence or absence of radiologic signs of lung contusion at the time of offer has no impact on primary graft function and long-term survival.

Effects of nitric oxide donor on the lung functions in a saline lavage-induced model of ARDS

Acute respiratory distress syndrome (ARDS) is characterized by acute hypoxemia, neutrophil-mediated inflammation, and lung edema formation. Whereas lung damage might be alleviated by nitric oxide (NO), goal of this study was to evaluate if intratracheal NO donor S-nitroso-N-acetylpenicillamine (SNAP) can positively influence the lung functions in experimental model of ARDS. New Zealand rabbits with respiratory failure induced by saline lavage (30 ml/kg, 9+/-3 times) were divided into: ARDS group without therapy, ARDS group treated with SNAP (7 mg/kg i.t.), and healthy Control group. During 5 h of ventilation, respiratory parameters (blood gases, ventilatory pressures) were estimated. After anesthetics overdosing, left lung was saline-lavaged and cell count, cell viability and protein content in bronchoalveolar lavage fluid (BALF) were measured. Right lung tissue was used for estimation of wet/dry weight ratio, concentration of NO metabolites, and histomorphological investigation. Repetitive lung lavage induced lung injury, worsened gas exchange, and damaged alveolar-capillary membrane. Administration of SNAP reduced cell count in BALF, lung edema formation, NO metabolites, and histopathological signs of injury, and improved respiratory parameters. Treatment with intratracheal SNAP alleviated lung injury and edema and improved lung functions in a saline-lavaged model of ARDS suggesting a potential of NO donors also for patients with ARDS.

Antioxidant treatment after injury suppresses second hit immune priming

BACKGROUND

Pulmonary contusion (PC) is a common injury that often results in priming for exaggerated inflammatory responses to a second hit. Previous studies used a mouse model of pulmonary contusion and showed an early and sustained reduction of SIRT1 protein and activity in the lung and bronchoalveolar lavage (BAL) cells of injured mice. Sustained decrease in SIRT1 was associated with a primed phenotype in injured mice challenged with an inflammatory stimulus. This study tests the hypothesis that pulmonary contusion induces oxidant production that modifies and decreases SIRT1 and primes the lung for the second-hit response.

METHODS

A mouse model of pulmonary contusion was used to investigate injury-induced oxidant changes in SIRT1. Second-hit responses were evaluated by infection (Streptococcus pneumoniae) and inflammatory challenge using bacterial lipopolysaccharide. BAL, lung tissue, and blood were collected and used to evaluate inflammatory responses and SIRT1 levels, oxidant modification, and activity. Levels of NO in the BAL from mice and patients with PC were also assessed.

RESULTS

We found that oxidants produced as a result of pulmonary contusion resulted in modification of SIRT1. S-Nitrosylation was observed and correlated with increased inducible nitric oxide synthase expression after injury. Anti-oxidant treatment of injured mice preserved SIRT1 activity, decreased second hit responses and improved lung function. Elevated NO levels in the BAL of PC patients was associated with acute respiratory distress syndrome or diagnosis of pneumonia.

CONCLUSIONS

We conclude that oxidative stress in the lung after injury induces redox modification of SIRT1 and contributes to priming of the lung for a second-hit response. Antioxidant treatment suggests that SIRT1 activity after injury may be beneficial in suppressing second-hit responses.

Investigating Cyclooxygenase Inhibition in a Rat Pulmonary Contusion Model: A Laboratory Study Finding No Improvement with Ibuprofen

Minimal advances have been made in the management of pulmonary contusions (PCs). The purpose of this study was to evaluate the impact of cyclooxygenase inhibition on outcomes following PC in a rat model. PC was induced in anesthetized adult rats. Ibuprofen was given to the treatment group (TG) and water was given to the control group (CG). Lung injury was assessed with pulse oximetry, arterial blood gases, CT, and histopathologic examination. Inflammation was measured with both serum and bronchoalveolar lavage (BAL) levels of tumor necrosis factor a and interleukin-6. Rats in the TG did not differ from rats in the CG with respect to oxygenation. Pathologic examination demonstrated a trend toward more inflammatory infiltrate in the CG, yet the sizes of the contusions were larger in the TG. The CG trended toward decreased levels of interleukin-6 in the serum and BAL at both three and seven days. While BAL levels of tumor necrosis factor a were increased in the TG at three days compared to the CG, they trended toward a reduced amount at seven days. Our data do not support cyclooxygenase inhibition for treatment to decrease the respiratory compromise associated with PC in this model of rat PCs.

Effects of sphingosylphosphorylcholine against oxidative stress and acute lung ınjury ınduced by pulmonary contusion in rats

BACKGROUND/PURPOSE

The goal of this study was to evaluate effects of exogenous sphingosylphosphorylcholine (SPC) administration on acute lung injury induced by pulmonary contusion in rats.

METHODS

Eight animals were included in each of the following five groups: control, contusion, contusion phosphate-buffered solution (PBS), contusion SPC 2, contusion SPC 10. SPC was administered 3 days at a daily two different doses of 2 μm/ml and 10 μm/ml intraperitoneally. The severity of lung injury was determined by the neutrophil activation and histological and immunohistochemical changes in the lung. Malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione (GSH) were determined to evaluate the oxidative status in the lung tissue.

RESULTS

Treatment with 2 μM SPC inhibited the increase in lung MDA and NO levels significantly and also attenuated the depletion of SOD, GPx, and GSH in the lung injury induced by pulmonary contusion. These data were supported by histopathological findings. The inducible nitric oxide synthase (iNOS) positive cells and apoptotic cells in the lung tissue were observed to be reduced with the 2 μM SPC treatment. But, the 10 μM SPC treatment did not provide similar effects.

CONCLUSIONS

In conclusion, these findings suggested that 2 μM SPC can attenuate lung damage in pulmonary contusion by prevention of oxidative stress, inflammatory process and apoptosis. All these findings suggest that low dose SPC may be a promising new therapeutic agent for acute lung injury.

Activation of hypoxia-inducible factor-1α in type 2 alveolar epithelial cell is a major driver of acute inflammation following lung contusion

OBJECTIVE

Lung contusion is a major risk factor for the development of acute respiratory distress syndrome. Hypoxia-inducible factor-1α is the primary transcription factor that is responsible for regulating the cellular response to changes in oxygen tension. We set to determine if hypoxia-inducible factor-1α plays a role in the pathogenesis of acute inflammatory response and injury in lung contusion.

DESIGN

Nonlethal closed-chest unilateral lung contusion was induced in a hypoxia reporter mouse model and type 2 cell-specific hypoxia-inducible factor-1α conditional knockout mice. The mice were killed at 5-, 24-, 48-, and 72-hour time points, and the extent of systemic and tissue hypoxia was assessed. In addition, injury and inflammation were assessed by measuring bronchoalveolar lavage cells (flow cytometry and cytospin), albumin (permeability injury), and cytokines (inflammation). Isolated type 2 cells from the hypoxia-inducible factor-1α conditional knockout mice were isolated and evaluated for proinflammatory cytokines following lung contusion. Finally, the role of nuclear factor-κB and interleukin-1β as intermediates in this interaction was studied.

RESULTS

Lung contusion induced profound global hypoxia rapidly. Increased expression of hypoxia-inducible factor-1α from lung samples was observed as early as 60 minutes, following the insult. The extent of lung injury following lung contusion was significantly reduced in conditional knockout mice at all the time points, when compared with the wild-type littermate mice. Release of proinflammatory cytokines, such as interleukin-1β, interleukin-6, macrophage inflammatory protein-2, and keratinocyte chemoattractant, was significantly lower in conditional knockout mice. These actions are in part mediated through nuclear factor-κB. Hypoxia-inducible factor-1α in lung epithelial cells was shown to regulate interleukin-1β promoter activity.

CONCLUSION

Activation of hypoxia-inducible factor-1α in type 2 cell is a major driver of acute inflammation following lung contusion.

Inducible nitric oxide synthase inhibition reverses pulmonary arterial dysfunction in lung transplantation

BACKGROUND

Ischemia-reperfusion injury (IRI) after lung transplantation remains a significant cause of morbidity and mortality. Lung IRI induces nitric oxide synthesis (iNOS) and reactive nitrogen species, decreasing nitric oxide bioavailability. We hypothesized that ischemia-induced iNOS intensifies with reperfusion and contributes to IRI-induced pulmonary arterial regulatory dysfunction, which may lead to early graft failure and cause pulmonary edema. The aim of this study was to determine whether ischemia-reperfusion alters inducible and endothelial nitric oxide synthase expression, potentially affecting pulmonary perfusion. We further evaluated the role of iNOS in post-transplantation pulmonary arterial disorder.

METHODS

We randomized 32 Sprague-Dawley rats into two groups. The control group was given a sham operation whilst the experimental group received orthotropic lung transplants with a modified three-cuff technique. Changes in lung iNOS, and endothelial nitric oxide synthase expression were measured after lung transplantation by enzyme-linked immunosorbent assay (ELISA). Vasoconstriction in response to exogenous phenylephrine and vasodilation in response to exogenous acetylcholine of pulmonary arterial rings were measured in vitro as a measure of vascular dysfunction. To elucidate the roles of iNOS in regulating vascular function, an iNOS activity inhibitor (N6-(1-iminoethyl)-L-lysine, L-NIL) was used to treat isolated arterial rings. In order to test whether iNOS inhibition has a therapeutic effect, we further used L-NIL to pre-treat transplanted lungs and then measured post-transplantation arterial responses.

RESULTS

Lung transplantation caused upregulation of iNOS expression. This was also accompanied by suppression of both vasoconstriction and vasodilation of arterial rings from transplanted lungs. Removal of endothelium did not interfere with the contraction of pulmonary arterial rings from transplanted lungs. In contrast, iNOS inhibition rescued the vasoconstriction response to exogenous phenylephrine of pulmonary arterial rings from transplanted lungs. In addition, lung transplantation led to suppression of PaO2/FiO2 ratio, increased intrapulmonary shunt (Q s/Q t), and increase of lung wet to dry ratio (W/D), malondialdehyde and myeloperoxidase levels, all of which were reversed upon iNOS inhibition. Furthermore, inhibition of iNOS significantly rescued vascular function and alleviated edema and inflammatory cell infiltration in the transplanted lung.

CONCLUSIONS

Our data suggest that lung transplantation causes upregulation of iNOS expression, and pulmonary vascular dysfunction. iNOS inhibition reverses the post-transplantational pulmonary vascular dysfunction.

The protective role of MnTBAP in oxidant-mediated injury and inflammation in a rat model of lung contusion

BACKGROUND

Lung contusion (LC) is a unique direct and focal insult that is considered a major risk factor for the initiation of acute lung injury and acute respiratory distress syndrome. We have shown recently that consumption of nitric oxide (due to excess superoxide) resulting in peroxynitrite formation leads to decreased vascular reactivity after LC. In this study, we set out to determine whether the superoxide scavenger Mn (III) tetrakis (4-benzoic acid) porphyrin chloride (MnTBAP) plays a protective role in alleviating acute inflammatory response and injury in LC.

METHODS

Nonlethal, closed-chest, bilateral LC was induced in a rodent model. Administration of the superoxide dismutase mimetic MnTBAP concurrently in LC in rats was performed, and bronchoalveolar lavage (BAL) and lung samples were analyzed for degree of injury and inflammation at 5 and 24 h after the insult. The extent of injury was assessed by the measurement of cells and albumin with cytokine levels in the BAL and lungs. Lung samples were subjected to H&E and superoxide staining with dihydro-ethidium. Protein-bound dityrosine and nitrotyrosine levels were quantified in lung tissue by tandem mass spectrometry.

RESULTS

The degrees of lung injury after LC as determined by BAL albumin levels were significantly decreased in the MnTBAP-administered rats at all the time points when compared to the corresponding controls. The release of proinflammatory cytokines and BAL neutrophils was significantly less in the rats administered MnTBAP after LC. Administration of MnTBAP decreased tissue damage and decreased necrosis and neutrophil-rich exudate at the 24-h time point. Staining for superoxide anions showed significantly greater intensity in the lung samples from the LC group compared to the LC+ MnTBAP group. High-performance liquid chromatography/tandem mass spectrometry revealed that MnTBAP treatment significantly attenuated dityrosine and nitrotyrosine levels, consistent with decreased oxidant injury.

CONCLUSION

Superoxide dismutase mimetic-MnTBAP reduced permeability and oxidative injury in LC and may have a therapeutic role in diminishing inflammation in LC.

Desferrioxamine reduces oxidative stress in the lung contusion

Our hypothesis in this study is that desferrioxamine (DFX) has therapeutic effects on experimental lung contusions in rats. The rats were divided into four groups (n = 8): control, control+DFX, contusion, and contusion+DFX. In the control+DFX and contusion+DFX groups, 100 mg/kg DFX was given intraperitoneally once a day just after the contusion and the day after the contusion. Contusions led to a meaningful rise in the malondialdehyde (MDA) level in lung tissue. MDA levels in the contusion+DFX group experienced a significant decline. Glutathione levels were significantly lower in the contusion group than in the control group and significantly higher in the contusion+DFX group. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) levels in the contusion group were significantly lower than those in the control group. In the contusion+DFX group, SOD and GPx levels were significantly higher than those in the contusion group. In light microscopic evaluation, the contusion and contusion+DFX groups showed edema, hemorrhage, alveolar destruction, and leukocyte infiltration. However, histological scoring of the contusion+DFX group was significantly more positive than that of the contusion group. The iNOS staining in the contusion group was significantly more intensive than that in all other groups. DFX reduced iNOS staining significantly in comparison to the contusion group. This study showed that DFX reduced oxidative stress in lung contusions in rats and histopathologically ensured the recovery of the lung tissue.