Evaluating the Impact of Ex Vivo Lung Perfusion on Organ Transplantation: A Retrospective Cohort Study.

BACKGROUND: Ex vivo lung perfusion (EVLP) sustains and allows advanced assessment of potentially useable donor lungs before transplantation, potentially relieving resource constraints. OBJECTIVE: We sought to characterize the effect of EVLP on organ utilization and patient outcomes. METHODS: We performed a retrospective, before-after cohort study using linked institutional data sources of adults wait-listed for lung transplant and donor organs transplanted in Ontario, Canada between 2005 and 2019. We regressed the annual number of transplants against year, EVLP use, and organ characteristics. Time-to-transplant, waitlist mortality, primary graft dysfunction, tracheostomy insertion, in-hospital mortality, and chronic lung allograft dysfunction were evaluated using propensity score-weighted regression. RESULTS: EVLP availability ( P =0.01 for interaction) and EVLP use ( P <0.001 for interaction) were both associated with steeper increases in transplantation than expected by historical trends. EVLP was associated with more donation after circulatory death and extended-criteria donors transplanted, while the numbers of standard-criteria donors remained relatively stable. Significantly faster time-to-transplant was observed after EVLP was available (hazard ratio=1.64 [1.41-1.92]; P <0.001). Fewer patients died on the waitlist after EVLP was available, but no difference in the hazard of waitlist mortality was observed (HR=1.19 [0.81-1.74]; P =0.176). We observed no difference in the likelihood of chronic lung allograft dysfunction before versus after EVLP was available. CONCLUSIONS: We observed a significant increase in organ transplantation since EVLP was introduced into practice, predominantly from increased acceptance of donation after circulatory death and extended-criteria lungs. Our findings suggest that EVLP-associated increases in organ availability meaningfully alleviated some barriers to transplant.

Thrombopoietin participates in platelet activation in COVID-19 patients.

BACKGROUND: The pathogenesis of coronavirus disease 2019 (COVID-19) is characterized by enhanced platelet activation and diffuse hemostatic alterations, which may contribute to immunothrombosis/thromboinflammation and subsequent development of target-organ damage. Thrombopoietin (THPO), a growth factor essential to megakariocyte proliferation, is known to prime platelet activation and leukocyte-platelet interaction. In addition, THPO concentrations increase in several critical diseases, such as acute cardiac ischemia and sepsis, thus representing a potential diagnostic and prognostic biomarker. Furthermore, several data suggest that interleukin (IL)-6 is one of the most important inflammatory mediators involved in these phenomena, which led to explore the potential therapeutic role of IL-6 inhibitors. In this prospective cohort study, we aimed to study THPO and IL-6 concentrations in COVID-19 patients at the time of first clinical evaluation in the Emergency Department (ED), and to investigate their potential use as diagnostic and prognostic biomarkers. In addition, we sought to explore the role of THPO contained in plasma samples obtained from COVID-19 patients in priming in vitro platelet activation and leukocyte-platelet interaction. METHODS: We enrolled 66 patients presenting to the ED with symptoms suggestive of COVID-19, including 47 with confirmed COVID-19 and 19 in whom COVID-19 was excluded (Non-COVID-19 patients). As controls, we also recruited 18 healthy subjects. In vitro, we reproduced the effects of increased circulating THPO on platelet function by adding plasma from COVID-19 patients or controls to platelet-rich plasma or whole blood obtained by healthy donors, and we indirectly studied the effect of THPO on platelet activation by blocking its biological activity. FINDINGS: THPO levels were higher in COVID-19 patients than in both Non-COVID-19 patients and healthy subjects. Studying THPO as diagnostic marker for the diagnosis of COVID-19 by receiver-operating-characteristic (ROC) statistics, we found an area under the curve (AUC) of 0.73, with an optimal cut-off value of 42.60 pg/mL. IL-6 was higher in COVID-19 patients than in healthy subjects, but did not differ between COVID-19 and Non-COVID-19 patients. THPO concentrations measured at the time of diagnosis in the ED were also higher in COVID-19 patients subsequently developing a severe disease than in those with mild disease. Evaluating THPO as biomarker for severe COVID-19 using ROC analysis, we found an AUC of 0.71, with an optimal cut-off value of 57.11 pg/mL. IL-6 was also higher in severe than in mild COVID-19 patients, with an AUC for severe COVID-19 of 0.83 and an optimal cut-off value of 23 pg/ml. THPO concentrations correlated with those of IL-6 (r=0.2963; p=0.043), and decreased 24 h after the administration of tocilizumab, an IL-6 receptor blocking antibody, showing that the increase of THPO levels depends on IL-6-stimulated hepatic synthesis. In vitro, plasma obtained from COVID-19 patients, but not from healthy subjects, primed platelet aggregation and leukocyte-platelet binding, and these effects were reduced by inhibiting THPO activity. INTERPRETATION: Increased THPO may be proposed as an early biomarker for the diagnosis of COVID-19 and for the identification of patients at risk of developing critical illness. Elevated THPO may contribute to enhance platelet activation and leukocyte-platelet interaction in COVID-19 patients, thus potentially participating in immunothrombosis/thromboinflammation. FUNDING: This work was supported by Ministero dell'Università e della Ricerca Scientifica e Tecnologica (MURST) ex 60% to GM and EL.

A biomarker assay to risk-stratify patients with symptoms of respiratory tract infection.

BACKGROUND: Patients who present to an emergency department (ED) with respiratory symptoms are often conservatively triaged in favour of hospitalisation. We sought to determine if an inflammatory biomarker panel that identifies the host response better predicts hospitalisation in order to improve the precision of clinical decision making in the ED. METHODS: From April 2020 to March 2021, plasma samples of 641 patients with symptoms of respiratory illness were collected from EDs in an international multicentre study: Canada (n=310), Italy (n=131) and Brazil (n=200). Patients were followed prospectively for 28 days. Subgroup analysis was conducted on confirmed coronavirus disease 2019 (COVID-19) patients (n=245). An inflammatory profile was determined using a rapid, 50-min, biomarker panel (RALI-Dx (Rapid Acute Lung Injury Diagnostic)), which measures interleukin (IL)-6, IL-8, IL-10, soluble tumour necrosis factor receptor 1 (sTNFR1) and soluble triggering receptor expressed on myeloid cells 1 (sTREM1). RESULTS: RALI-Dx biomarkers were significantly elevated in patients who required hospitalisation across all three sites. A machine learning algorithm that was applied to predict hospitalisation using RALI-Dx biomarkers had a mean±sd area under the receiver operating characteristic curve of 76±6% (Canada), 84±4% (Italy) and 86±3% (Brazil). Model performance was 82±3% for COVID-19 patients and 87±7% for patients with a confirmed pneumonia diagnosis. CONCLUSIONS: The rapid diagnostic biomarker panel accurately identified the need for inpatient care in patients presenting with respiratory symptoms, including COVID-19. The RALI-Dx test is broadly and easily applicable across many jurisdictions, and represents an important diagnostic adjunct to advance ED decision-making protocols.

Donor ventilation parameters as predictors for length of mechanical ventilation after lung transplantation: Results of a prospective multicenter study.

BACKGROUND: The evaluation of donor lungs heavily depends on the subjective judgment of the retrieval surgeon. As a consequence, acceptance rates vary significantly among transplant centers. We aimed to determine donor ventilation parameters in a prospective study and test if they could be used as objective quality criteria during organ retrieval. METHODS: A prospective evaluation of lung donors was performed in 3 transplant centers. Ventilation parameters were collected at the time of retrieval using a standardized ventilation protocol. Recipient length of mechanical ventilation (LMV) was defined as the primary end point, and collected data was used to build linear models predicting LMV. RESULTS: In total, 166 donors were included in this study. Median LMV after transplantation was 32 hours (interquartile range: 20-63 hours). Peak inspiratory pressure and dynamic compliance (Cdyn) at the time of retrieval, but not the partial pressure of oxygen/fraction of inspired oxygen (P/F) ratio, correlated with recipient LMV in Spearman correlations (r = 0.280, p = 0.002; r = -0.245, p = 0.003; and r = 0.064, p = 0.432, respectively). Linear models were built to further evaluate the impact of donor ventilation parameters on LMV. The first model was based on donor P/F ratio, donor age, donor intubation time, donor smoking history, donor partial pressure of carbon dioxide, aspiration, chest trauma, and pathologic chest X-ray. This model performed poorly (multiple R-squared = 0.063). In a second model, donor ventilation parameters were included, and Cdyn was identified as the strongest predictor for LMV. The third model was extended by recipient factors, which significantly improved the robustness of the model (multiple R-squared = 0.293). CONCLUSION: In this prospective evaluation of donor lung parameters, currently used donor quality criteria poorly predicted recipient LMV. Our data suggest that Cdyn is a strong donor-bound parameter to predict short-term graft performance; however, recipient factors are similarly relevant.

Effect of Driving Pressure Change During Extracorporeal Membrane Oxygenation in Adults With Acute Respiratory Distress Syndrome: A Randomized Crossover Physiologic Study.

OBJECTIVES: Venovenous extracorporeal membrane oxygenation is an effective intervention to improve gas exchange in patients with severe acute respiratory distress syndrome. However, the mortality of patients with severe acute respiratory distress syndrome supported with venovenous extracorporeal membrane oxygenation remains high, and this may be due in part to a lack of standardized mechanical ventilation strategies aimed at further minimizing ventilator-induced lung injury. We tested whether a continuous positive airway pressure ventilation strategy mitigates ventilator-induced lung injury in patients with severe acute respiratory distress syndrome on venovenous extracorporeal membrane oxygenation, compared with current ventilation practice that employs tidal ventilation with limited driving pressure. We used plasma biomarkers as a surrogate outcome for ventilator-induced lung injury. DESIGN: Randomized crossover physiologic study. SETTING: Single-center ICU. PATIENTS: Ten patients with severe acute respiratory distress syndrome supported on venovenous extracorporeal membrane oxygenation. INTERVENTIONS: The study included four phases. After receiving pressure-controlled ventilation with driving pressure of 10 cm H2O for 1 hour (phase 1), patients were randomly assigned to receive first either pressure-controlled ventilation 20 cm H2O for 2 hours (phase 2) or continuous positive airway pressure for 2 hours (phase 3), and then crossover to the other phase for 2 hours; during phase 4 ventilation settings returned to baseline (pressure-controlled ventilation 10 cm H2O) for 4 hours. MEASUREMENTS AND MAIN RESULTS: There was a linear relationship between the change in driving pressure and the plasma concentration of interleukin-6, soluble receptor for advanced glycation end products, interleukin-1ra, tumor necrosis factor alpha, surfactant protein D, and interleukin-10. CONCLUSIONS: Ventilator-induced lung injury may occur in acute respiratory distress syndrome patients on venovenous extracorporeal membrane oxygenation despite the delivery of volume- and pressure-limited mechanical ventilation. Reducing driving pressure to zero may provide more protective mechanical ventilation in acute respiratory distress syndrome patients supported with venovenous extracorporeal membrane oxygenation. However, the risks versus benefits of such an approach need to be confirmed in studies that are designed to test patient centered outcomes.

Impact of imipenem concentration in lung perfusate and tissue biopsy during clinical ex-vivo lung perfusion of high-risk lung donors.

BACKGROUND: Normothermic ex-vivo lung perfusion (EVLP) limits organ donor shortage by potentially using high-risk donor lungs. Microbial burden reduction has been demonstrated after EVLP using antibiotic prophylaxis with imipenem. However, no data have been published on the clinical consequences of the potential residual bacterial burden. METHODS: Imipenem concentration was measured every hour (T0 to T6) in the lung perfusate and at the end of EVLP (Tf) in biopsies. The antimicrobial activity of perfusate at T1 and Tf against E. coli and K. pneumoniae was evaluated. Lungs were distinguished: no bacterial species in recipients and donors (donor-/recipient-); bacterial species isolated from donors and not from recipients (donor+/recipient-); same bacterial species in both recipients and donors (donor+/recipient+). Interleukin 6 (IL-6) and IL-8 concentrations in lung perfusate, clinical pulmonary infection score (CPIS) and primary graft dysfunction (PGD) were evaluated. RESULTS: Imipenem concentration in perfusate decreased over time. T1 and Tf perfusates exhibited bactericidal activity against E. coli and K. pneumoniae. Overall, T1 perfusates yielded higher bactericidal titers (BTs) than Tf. The donor+/recipient+ group (26% of cases) had higher IL-6 and IL-8 in perfusate and higher CPIS. CONCLUSIONS: Recipients with the same bacterial species isolated in their donors had higher risk of pulmonary inflammation and early post-transplant pneumonia. Improvements in antimicrobial strategies during EVLP are warranted to minimize the consequences of donor associated respiratory infection.

Veno-venous extracorporeal life support for blastomycosis-associated acute respiratory distress syndrome.

BACKGROUND: Blastomyces is a dimorphic fungus endemic to regions of North America, which can lead to pneumonia and fatal severe acute respiratory diseases syndrome in up to 89% of patients. Extracorporeal life support can provide adequate oxygenation while allowing the lungs to rest and heal, which might be an ideal therapy in this patient group, although long-term clinical and radiological outcomes are not known. CLINICAL FEATURES: We report on five consecutive patients admitted to Toronto General Hospital intensive care unit between January 2012 and September 2016, with progressive respiratory failure requiring veno-venous extracorporeal life support within 24-96 hours following mechanical ventilation. Ultra-lung protective mechanical ventilation was achieved within 24 hours. Recovery was the initial goal in all patients. Extracorporeal life support was provided for a prolonged period (up to 49 days), and four patients were successfully discharged from the intensive care unit. Long-term radiological assessment in three patients showed major improvement within 2 years of follow-up with some persistent disease-related changes (bronchiectasis, fibrosis, and cystic changes). In two patients, long-term functional and neuropsychological outcomes showed similar limitations to what is seen in acute respiratory distress syndrome patients who are not supported with extracorporeal life support and in acute respiratory distress syndrome patients without blastomycosis, but worse pulmonary function outcomes in the form of obstructive and restrictive changes that correlated with the radiological imaging. CONCLUSION: Veno-venous extracorporeal life support can effectively provide prolonged support for patients with blastomycosis-associated acute respiratory distress syndrome that is safe and associated with favorable long-term outcomes.

Effects of liver ischemia-reperfusion injury on respiratory mechanics and driving pressure during orthotopic liver transplantation.

BACKGROUND: During orthotopic liver transplantation (OLT), liver graft ischemia-reperfusion injury (IRI) triggers a cytokine-mediated systemic inflammatory response, which impairs graft function and disrupts distal organ homeostasis. The objective of this prospective, observational trial was to assess the effects of IRI on lung and chest wall mechanics in the intraoperative period of patients undergoing OLT. METHODS: In 26 patients undergoing OLT, we measured elastance of the respiratory system (ERS), partitioned into lung (EL) and chest wall (ECW), hemodynamics, and fluid and blood product intake before laparotomy (T1), after portal/caval surgical clamp (T2), and immediately (T3) and, at 90 and 180 minutes post-reperfusion (T4 and T5, respectively). Interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), IL-1ß and tumor necrosis factor-α plasma concentrations were assessed at T1, T4 and T5. RESULTS: EL significantly decreased from T1 to T2 (13.5±4.4 vs 9.7±4.8 cmH2O/L, P<0.05), remained stable at T3, while at T4 (12.3±4.4 cmH2O/L, P<0.05) was well above levels recorded at T2, reaching its highest value at T5 (15±3.9 cmH2O/L, P<0.05). Variations in ERS, EL, driving pressure (∆P) and trans-pulmonary pressure (∆PL) significantly correlated with changes in IL-6 and MCP-1 plasma concentrations, but not with changes in wedge pressure, fluid amounts, and red blood cells and platelets administered. No correlation was found between changes in cytokine concentrations and ECW. CONCLUSIONS: We found that EL, ECW, ∆P and ∆PL underwent significant variations during the OLT procedure. Further, we documented a significant association between the respiratory mechanics changes and the inflammatory response following liver graft reperfusion.

The Impact of High-Flow Nasal Oxygen in the Immunocompromised Critically Ill: A Systematic Review and Meta-Analysis.

BACKGROUND: High-flow nasal-cannula (HFNC) may be an oxygen modality useful for preventing invasive mechanical ventilation and mortality; however, its role in acute hypoxemic respiratory failure is not clearly defined. We sought to evaluate the impact of HFNC on mortality across immunocompromised subjects compared to alternative noninvasive oxygen therapies, namely conventional oxygen therapy and noninvasive ventilation (NIV). METHODS: We systematically searched the major databases to identify randomized, controlled trials (RCTs) or observational studies (until May 2018). We included studies reporting the use of HFNC in immunocompromised subjects and evaluated its impact on mortality and invasive mechanical ventilation. RESULTS: Upon review of 6,506 titles, 13 studies (1,956 subjects) fulfilled our inclusion criteria (4 RCTs, 9 observational studies). The predominant cause of immunocompromised status was cancer. Bacterial pneumonia was the most common cause of acute hypoxemic respiratory failure with a median PaO2/FIO2 of 145 mm Hg (interquartile range 115-175). HFNC was used as the first oxygen strategy in 474 subjects compared to NIV (242 subjects) and conventional O2 therapy (703 subjects). There was a 46% rate of invasive mechanical ventilation and 36% mortality. Mortality at the longest available follow-up was lower with HFNC compared to the oxygen therapy controls (NIV or conventional O2 therapy) in 7 studies (1,429 subjects; relative risk 0.72, 95% CI 0.56-0.93, P = .01). There was a lower rate of invasive mechanical ventilation with HFNC compared to the oxygen therapy controls across 8 studies (1,529 subjects, relative risk 0.81, 95% CI 0.67-0.96, P = .02). These results were robust across a series of sensitivity analyses. CONCLUSIONS: There exists a need to develop a greater evidence base evaluating the utility of HFNC in immunocompromised subjects. In our exploratory analysis, HFNC was found to decrease mortality and use of invasive mechanical ventilation compared to alternative noninvasive oxygen controls. These results are meant to be exploratory. Higher-quality studies evaluating a more homogeneous population are needed to further elucidate its benefit.

Extracorporeal life support as a bridge to lung transplantation-experience of a high-volume transplant center.

OBJECTIVES: Extracorporeal life support (ECLS) is increasingly used to bridge deteriorating patients awaiting lung transplantation (LTx), however, few systematic descriptions of this practice exist. We therefore aimed to review our institutional experience over the past 10 years. METHODS: In this case series, we included all adults who received ECLS with the intent to bridge to LTx. Data were retrieved from patient charts and our institutional ECLS and transplant databases. RESULTS: Between January 2006 and September 2016, 1111 LTx were performed in our institution. ECLS was used in 71 adults with the intention to bridge to LTx; of these, 11 (16%) were bridged to retransplantation. The median duration of ECLS before LTx was 10 days (range, 0-95). We used a single dual-lumen venous cannula in 23 patients (32%). Nine of 13 patients (69%) with pulmonary hypertension were bridged by central pulmonary artery to left atrium Novalung. Twenty-five patients (35%) were extubated while on ECLS and 26 patients (37%) were mobilized. Sixty-three patients (89%) survived to LTx. Survival by intention to treat was 66% (1 year), 58% (3 years) and 48% (5 years). Survival was significantly shorter in patients undergoing ECLS bridge to retransplantation compared with first LTx (median survival, 15 months (95% CI, 0-31) versus 60 months (95% CI, 37-83); P = .041). CONCLUSIONS: In our center experience, ECLS bridge to first lung transplant leads to good short-term and long-term outcomes in carefully selected patients. In contrast, our data suggest that ECLS as a bridge to retransplantation should be used with caution.

Tsr Chemoreceptor Interacts With IL-8 Provoking E. coli Transmigration Across Human Lung Epithelial Cells.

Bacterial colonization of epithelial surfaces and subsequent transmigration across the mucosal barrier are essential for the development of infection. We hypothesized that the methyl-accepting proteins (MCPs), known as chemoreceptors expressed on Escherichia coli (E. coli) bacterial surface, play an important role in mediating bacterial transmigration. We demonstrated a direct interaction between human interleukin-8 (IL-8) and Tsr receptor, a major MCP chemoreceptor. Stimulation of human lung epithelial cell monolayer with IL-8 resulted in increased E. coli adhesion and transmigration of the native strain (RP437) and a strain expressing only Tsr (UU2373), as compared to a strain (UU2599) with Tsr truncation. The augmented E. coli adhesion and migration was associated with a higher expression of carcinoembryonic antigen-related cell adhesion molecule 6 and production of inflammatory cytokines/chemokines, and a lower expression of the tight junction protein claudin-1 and the plasma membrane protein caveolin-1 in lung epithelial cells. An increased E. coli colonization and pulmonary cytokine production induced by the RP437 and UU2373 strains was attenuated in mice challenged with the UU2599 strain. Our results suggest a critical role of the E. coli Tsr chemoreceptor in mediating bacterial colonization and transmigration across human lung epithelium during development of pulmonary infections.

Non-invasive ventilation in immunocompromised patients with acute hypoxemic respiratory failure.

The survival rate of immunocompromised patients has improved over the past decades in light of remarkable progress in diagnostic and therapeutic options. Simultaneously, there has been an increase in the number of immunocompromised patients with life threatening complications requiring intensive care unit (ICU) treatment. ICU admission is necessary in up to 15% of patients with acute leukemia and 20% of bone marrow transplantation recipients, and the main reason for ICU referral in this patient population is acute hypoxemic respiratory failure, which is associated with a high mortality rate, particularly in patients requiring endotracheal intubation. The application of non-invasive ventilation (NIV), and thus the avoidance of endotracheal intubation and invasive mechanical ventilation with its side effects, appears therefore of great importance in this patient population. Early trials supported the benefits of NIV in these settings, and the 2011 Canadian guidelines for the use of NIV in critical care settings suggest the use of NIV in immune-compromised patients with a grade 2B recommendation. However, the very encouraging results from initial seminal trials were not confirmed in subsequent observational and randomized clinical studies, questioning the beneficial effect of NIV in immune-compromised patients. Based on these observations, a French group led by Azoulay decided to assess whether early intermittent respiratory support with NIV had a role in reducing the mortality rate of immune-compromised patients with non-hypercapnic hypoxemic respiratory failure developed in less than 72 h, and hence conducted a multicenter randomized controlled trial (RCT) in experienced ICUs in France. This perspective reviews the findings from their RCT in the context of the current critical care landscape, and in light of recent results from other trials focused on the early management of acute hypoxemic respiratory failure.

Intratracheal Administration of Small Interfering RNA Targeting Fas Reduces Lung Ischemia-Reperfusion Injury.

OBJECTIVES: Lung ischemia-reperfusion injury is the main cause of primary graft dysfunction after lung transplantation and results in increased morbidity and mortality. Fas-mediated apoptosis is one of the pathologic mechanisms involved in the development of ischemia-reperfusion injury. We hypothesized that the inhibition of Fas gene expression in lungs by intratracheal administration of small interfering RNA could reduce lung ischemia-reperfusion injury in an ex vivo model reproducing the procedural sequence of lung transplantation. DESIGN: Prospective, randomized, controlled experimental study. SETTING: University research laboratory. SUBJECTS: C57/BL6 mice weighing 28-30 g. INTERVENTIONS: Ischemia-reperfusion injury was induced in lungs isolated from mice, 48 hours after treatment with intratracheal small interfering RNA targeting Fas, control small interfering RNA, or vehicle. Isolated lungs were exposed to 6 hours of cold ischemia (4°C), followed by 2 hours of warm (37°C) reperfusion with a solution containing 10% of fresh whole blood and mechanical ventilation with constant low driving pressure. MEASUREMENTS AND MAIN RESULTS: Fas gene expression was significantly silenced at the level of messenger RNA and protein after ischemia-reperfusion in lungs treated with small interfering RNA targeting Fas compared with lungs treated with control small interfering RNA or vehicle. Silencing of Fas gene expression resulted in reduced edema formation (bronchoalveolar lavage protein concentration and lung histology) and improvement in lung compliance. These effects were associated with a significant reduction of pulmonary cell apoptosis of lungs treated with small interfering RNA targeting Fas, which did not affect cytokine release and neutrophil infiltration. CONCLUSIONS: Fas expression silencing in the lung by small interfering RNA is effective against ischemia-reperfusion injury. This approach represents a potential innovative strategy of organ preservation before lung transplantation.

Incidence and severity of primary graft dysfunction after lung transplantation using rejected grafts reconditioned with ex vivo lung perfusion.

OBJECTIVES: Ex vivo lung perfusion (EVLP) is a novel technique used to evaluate and recondition marginal or rejected grafts. Primary graft dysfunction (PGD) is a major early complication after lung transplantation (LTx). The use of marginal or initially rejected grafts may increase its incidence and severity. The aim of this study is to evaluate the incidence of PGD after LTx using rejected grafts reconditioned with EVLP. METHODS: PGD has been evaluated immediately after LTx (t0) and after 72 h (t72) in patients receiving standard (Group A) or reconditioned (Group B) grafts. EVLP was performed using a controlled acellular perfusion according to the Toronto technique. RESULTS: From July 2011 to February 2013, 36 LTxs have been performed: 28 patients (21 M/7 F, mean age 51.7 ± 14.7 years) in Group A and 8 (6 M/2 F, mean age 46.6 ± 9.8 years) in Group B (successful recondition rate of 73%, 8 of 11 cases). Incidence rate of PGD 3 at t0 and at t72 (Group A versus Group B) was 50 vs 37% (P = NS) and 25 vs 0% (P = NS), respectively. Post-transplant extracorporeal membrane oxygenation was required in 5 and 2 patients in Groups A and B, respectively (P = NS). CONCLUSIONS: The use of initially rejected grafts treated with EVLP does not increase the incidence and severity of PGD after LTx. Although comparison of PGD 3 incidence in the two groups did not reach a statistical difference, all EVLP patients suffering from severe PGD early after transplant recovered normal lung function at 72 h, suggesting a protective role of EVLP against PGD occurrence and severity.

Pulmonary-derived phosphoinositide 3-kinase gamma (PI3Kγ) contributes to ventilator-induced lung injury and edema.

BACKGROUND: Ventilator-induced lung injury (VILI) occurs in part by increased vascular permeability and impaired alveolar fluid clearance. Phosphoinositide 3-kinase gamma (PI3Kγ) is activated by mechanical stress, induces nitric oxide (NO) production, and participates in cyclic adenosine monophosphate (cAMP) hydrolysis, each of which contributes to alveolar edema. We hypothesized that lungs lacking PI3Kγ or treated with PI3Kγ inhibitors would be protected from ventilation-induced alveolar edema and lung injury. METHODS: Using an isolated and perfused lung model, wild-type (WT) and PI3Kγ-knockout (KO) mice underwent negative-pressure cycled ventilation at either -25 cmH2O and 0 cmH2O positive end-expiratory pressure (PEEP) (HIGH STRESS) or -10 cmH2O and -3 cmH2O PEEP (LOW STRESS). RESULTS: Compared with WT, PI3Kγ-knockout mice lungs were partially protected from VILI-induced derangement of respiratory mechanics (lung elastance) and edema formation [bronchoalveolar lavage (BAL) protein concentration, wet/dry ratio, and lung histology]. In PI3Kγ-knockout mice, VILI induced significantly less phosphorylation of protein kinase B (Akt), endothelial nitric oxide synthase (eNOS), production of nitrate and nitrotyrosine, as well as hydrolysis of cAMP, compared with wild-type animals. PI3Kγ wild-type lungs treated with AS605240, an inhibitor of PI3Kγ kinase activity, in combination with enoximone, an inhibitor of phosphodiesterase-3 (PDE3)-induced cAMP hydrolysis, were protected from VILI at levels comparable to knockout lungs. CONCLUSIONS: Phosphoinositide 3-kinase gamma in resident lung cells mediates part of the alveolar edema induced by high-stress ventilation. This injury is mediated via altered Akt, eNOS, NO, and/or cAMP signaling. Anti-PI3Kγ therapy aimed at resident lung cells represents a potential pharmacologic target to mitigate VILI.

Phosphoinositide-3 kinase gamma activity contributes to sepsis and organ damage by altering neutrophil recruitment.

RATIONALE: Sepsis is a leading cause of death in the intensive care unit, characterized by a systemic inflammatory response (SIRS) and bacterial infection, which can often induce multiorgan damage and failure. Leukocyte recruitment, required to limit bacterial spread, depends on phosphoinositide-3 kinase γ (PI3Kγ) signaling in vitro; however, the role of this enzyme in polymicrobial sepsis has remained unclear. OBJECTIVES: This study aimed to determine the specific role of the kinase activity of PI3Kγ in the pathogenesis of sepsis and multiorgan damage. METHODS: PI3Kγ wild-type, knockout, and kinase-dead mice were exposed to cecal ligation and perforation-induced sepsis and assessed for survival; pulmonary, hepatic, and cardiovascular damage; coagulation derangements; systemic inflammation; bacterial spread; and neutrophil recruitment. Additionally, wild-type mice were treated either before or after the onset of sepsis with a PI3Kγ inhibitor and assessed for survival, neutrophil recruitment, and bacterial spread. MEASUREMENTS AND MAIN RESULTS: Both genetic and pharmaceutical PI3Kγ kinase inhibition significantly improved survival, reduced multiorgan damage, and limited bacterial decompartmentalization, while modestly affecting SIRS. Protection resulted from both neutrophil-independent mechanisms, involving improved cardiovascular function, and neutrophil-dependent mechanisms, through reduced susceptibility to neutrophil migration failure during severe sepsis by maintaining neutrophil surface expression of the chemokine receptor, CXCR2. Furthermore, PI3Kγ pharmacological inhibition significantly decreased mortality and improved neutrophil migration and bacterial control, even when administered during established septic shock. CONCLUSIONS: This study establishes PI3Kγ as a key molecule in the pathogenesis of septic infection and the transition from SIRS to organ damage and identifies it as a novel possible therapeutic target.

Continuous positive airway pressure for treatment of respiratory complications after abdominal surgery: a systematic review and meta-analysis.

OBJECTIVE: We evaluated the potential benefit of continuous positive airway pressure (CPAP) to prevent postoperative pulmonary complications (PPCs), atelectasis, pneumonia, and intubation in patients undergoing major abdominal surgery. SUMMARY BACKGROUND DATA: PPCs are common during the postoperative period and may be associated with a high morbidity rate. Efficacy of CPAP to prevent PPCs occurrence is controversial. METHODS: Medical literature databases were searched for randomized controlled trials examining the use of CPAP versus standard therapy in patients undergoing abdominal surgery. The meta-analysis estimated the pooled risk ratio and the number needed to treat to benefit (NNTB) for PPCs, atelectasis, and pneumonia. RESULTS: The meta-analysis was carried out over 9 randomized controlled trials. Overall, CPAP significantly reduced the risk of (1) PPCs (risk ratio, 0.66; 95% confidence interval [CI], 0.52-0.85) with a corresponding NNTB of 14.2 (95% CI, 9.9-32.4); (2) atelectasis (risk ratio, 0.75; 95% CI, 0.58-0.97; NNTB, 7.3; 95% CI, 4.4-64.5); (3) pneumonia (risk ratio, 0.33; 95% CI, 0.14-0.75; NNTB, 18.3; 95% CI, 14.4-48.8). In all cases the variation in risk ratio attributable to heterogeneity was negligible, although there was some evidence of publication bias. CONCLUSIONS: This systematic review suggests that CPAP decreases the risk of PPCs, atelectasis, and pneumonia and supports its clinical use in patients undergoing abdominal surgery.