Systemic Inflammation Differences in Brain-vs. Circulatory-Dead Donors: Impact on Lung Transplant Recipients.

Brain death triggers a systemic inflammatory response. Whether systemic inflammation is different in lung donors after brain- (DBD) or circulatory-death (DCD) is unknown, but this may potentially increase the incidence of primary graft dysfunction (PGD) after lung transplantation. We compared the plasma levels of interleukin (IL)-6, IL-8, IL-10 and TNF-α in BDB and DCD and their respective recipients, as well as their relationship with PGD and mortality after LT. A prospective, observational, multicenter, comparative, cohort-nested study that included 40 DBD and 40 DCD lung donors matched and their respective recipients. Relevant clinical information and blood samples were collected before/during lung retrieval in donors and before/during/after (24, 48 and 72 h) LT in recipients. Incidence of PGD and short-term mortality after LT was recorded. Plasma levels of all determined cytokines were numerically higher in DBD than in DCD donors and reached statistical significance for IL-6, IL-10 and IL-8. In recipients with PGD the donor's plasma levels of TNF-α were higher. The post-operative mortality rate was very low and similar in both groups. DBD is associated with higher systemic inflammation than DCD donors, and higher TNF-α plasma levels in donors are associated with a higher incidence of PGD.

The Role of Galectins in Chronic Lung Allograft Dysfunction.

BACKGROUND: Galectins are proteins that bind ß-galactosides such as N-acetyllactosamine present in N-linked and O-linked glycoproteins and that seem to be implicated in inflammatory and immune responses as well as fibrotic mechanisms. This preliminary study investigated serum galectins as clinical biomarkers in lung transplant patients with chronic lung allograft dysfunction (CLAD), phenotype bronchiolitis obliterans syndrome (BOS). MATERIALS AND METHODS: Nineteen lung transplant patients [median age (IQR), 55 (45-62) years; 53% males] were enrolled in the study. Peripheral blood concentrations of galectins-1, 3 and 9 were determined with commercial ELISA kits. RESULTS: Galectin-1 concentrations were higher in BOS than in stable LTX patients (p = 0.0394). In logistic regression analysis, testing BOS group as dependent variable with Gal-1 and 3 as independent variables, area under the receiver operating characteristics (AUROC) curve was 98.9% (NPV 90% and PPV 88.9%, p = 0.0003). With the stable LTX group as dependent variable and Gal-1, 3 and 9 as independent variables, AUROC was 92.6% (NPV 100% and PPV 90%, p = 0.0023). In stable patients were observed an inverse correlation of Gal-3 with DLCO% and KCO%, and between Gal-9 and KCO%. CONCLUSION: Galectins-1, 3 and 9 are possible clinical biomarkers in lung transplant patients with diagnostic and prognostic meaning. These molecules may be directly implicated in the pathological mechanisms of BOS. The hypothesis that they could be new therapeutic targets in BOS patients is intriguing and also worth exploring.

Early postoperative hemodynamic instability after heart transplantation - incidence and metabolic indicators.

BACKGROUND: Primary graft dysfunction (PGD) is the main cause of death in the first 30 days after heart transplantation (HTX), accounting for approximately 40% of mortality. The study's primary aim was to assess the incidence of PGD, following the International Society for Heart and Lung Transplantation consensus, and to compare it with the incidence of significant postoperative hypotension despite administration of high-dose inotropes and vasoconstrictors. The secondary aim of the study was to determine changes in biochemical markers that accompany the phenomenon. METHODS: Forty-five patients who underwent HTX between 2010 and 2015 were enrolled in this study, and detailed hemodynamic and metabolic data from the first 48 postoperative hours were collected and analyzed. Hemodynamic instability was defined as significant postoperative hypotension (mean arterial pressure (MAP) < 60 mmHg) combined with a high inotrope score (> 10). Data for long-term mortality were obtained from the population registration office. RESULTS: PGD incidence was relatively low (17.8%); however, hemodynamic instability was common (40%). Among unstable patients, MAP was insufficient for end-organ perfusion (51.4 ± 9.5 mmHg) but no decrease in left ventricular function was observed (cardiac index, 2.65 ± 0.6 l/min/m2; left ventricular ejection fraction, 52.9 ± 15.5%). Within this group, mean systemic vascular resistance index (961 ± 288 dyn*s*m2/cm5) was low despite receiving high doses of vasoactive agent (norepinephrine 0.21 (0.06-0.27) µg/kg/min during first 24 h postoperatively and 0.21 (0.01-0.27) µg/kg/min during next 24 h postoperatively). After HTX, serum lactate levels were initially significantly higher in patients with hemodynamic instability (p = 0.002); however, impaired lactate clearance was not observed (p = 0.366), and lactate levels normalized within the first 24 h postoperatively. Postoperative hemodynamic instability altered the long-term outcome and increased 5-year mortality after HTX (p = 0.034). CONCLUSIONS: Hemodynamic instability is a more common phenomenon than PGD. Only early postoperative serum lactate levels correspond with hemodynamic instability following HTX. Postoperative hemodynamic instability is associated with poor long-term survival among HTX recipients.

Postreperfusion plasma endothelial activation markers are associated with acute kidney injury after lung transplantation.

Acute kidney injury (AKI) is common after lung transplantation, but molecular markers remain poorly studied. The endothelial activation markers soluble thrombomodulin (sTM), protein C, and plasminogen activator inhibitor-1 (PAI-1) are implicated in kidney microcirculatory injury in animal models of AKI. We tested the association of 6-hour postreperfusion plasma levels of these markers with posttransplant AKI severity in patients enrolled in the Lung Transplant Outcomes Group prospective cohort study at the University of Pennsylvania during two eras: 2004-06 (n = 61) and 2013-15 (n = 67). We defined AKI stage through postoperative day 5 using Kidney Disease Improving Global Outcomes creatinine criteria. We used multivariable ordinal logistic regression to determine the association of each biomarker with AKI, adjusted for primary graft dysfunction and extracorporeal life support. AKI occurred in 57 (45%) patients across both eras: 28 (22%) stage 1, 29 (23%) stage 2-3. Higher sTM and lower protein C plasma levels were associated with AKI stage in each era and remained so in multivariable models utilizing both eras (sTM: OR 1.76 [95% CI 1.19-2.60] per standard deviation, P = .005; protein C: OR 0.54 [1.19-2.60], P = .003). We conclude that 6-hour postreperfusion plasma sTM and protein C levels are associated with early postlung transplant AKI severity.

Arterial Lactate Concentration at the End of Liver Transplantation Is an Early Predictor of Primary Graft Dysfunction.

BACKGROUND: Although many prognostic factors of primary graft dysfunction after liver transplantation (LT) are available, it remains difficult to predict failure in a given recipient. OBJECTIVE: We aimed to determine whether the intraoperative assay of arterial lactate concentration at the end of LT (LCEOT) might constitute a reliable biological test to predict early outcomes [primary nonfunction (PNF), early graft dysfunction (EAD)]. METHODS: We reviewed data from a prospective database in a single center concerning patients transplanted between January 2015 and December 2016 (n = 296). RESULTS: There was no statistical imbalance between the training (year 2015) and validation groups (year 2016) for epidemiological and perioperative feature. Ten patients (3.4%) presented with PNF, and EAD occurred in 62 patients (20.9%); 9 patients died before postoperative day (POD) 90. LCEOT ≥5 mmol/L was the best cut-off point to predict PNF (Se=83.3%, SP=74.3%, positive likelihood ratio (LR+)=3.65, negative likelihood ratio (LR-)=0.25, diagnostic odds ratio (DOR)=14.44) and was predictive of PNF (P = 0.02), EAD (P = 0.05), and death ≤ POD90 (P = 0.06). Added to the validated BAR-score, LCEOT improved its predictive value regarding POD 90 survival with a better AUC (0.87) than BAR score (0.74). The predictive value of LCEOT was confirmed in the validation cohort. CONCLUSION: As a reflection of both hypoperfusion and tissue damage, the assay of arterial LCEOT ≥5 mmol/L appears to be a strong predictor of early graft outcomes and may be used as an endpoint in studies assessing the impact of perioperative management. Its accessibility and low cost could impose it as a reliable parameter to anticipate postoperative management and help clinicians for decision-making in the first PODs.

Glycome Patterns of Perfusate in Livers Before Transplantation Associate With Primary Nonfunction.

BACKGROUND & AIMS: Primary nonfunction (PNF) is a rare complication after liver transplantation that requires urgent retransplantation. PNF is associated with livers from extended criteria donors. Clinical and biochemical factors have not been identified that reliably associate with graft function after liver transplantation. Serum patterns of N-glycans associate with changes in the liver. We analyzed perfusate from grafted liver to identify protein glycosylation patterns associated with PNF. METHODS: We performed a prospective study of consecutive patients who underwent liver transplantation (66 patients, from 1 center, in the derivation set, and 56 patients, from 2 centers, in the validation set) in Belgium, from October 1, 2011, through April 30, 2017. All donor grafts were transported using cold static storage, and perfusate samples were collected from the livers by flushing of hepatic veins before transplantation. Protein-linked N-glycans were isolated from perfusate samples and analyzed with a multicapillary electrophoresis-based ABI3130 sequencer. We compared glycan patterns between patients with vs without PNF of transplanted livers. PNF was defined as the need for urgent retransplantation when a graft had no evidence of function, after exclusion of other causes, such as hepatic artery thrombosis or acute cellular rejection. RESULTS: The relative abundance of a single glycan, agalacto core-alpha-1,6-fucosylated biantennary glycan (NGA2F) was significantly increased in perfusate of livers given to 4 patients who developed PNF after liver transplantation compared with livers given to patients who did not develop PNF. Level of NGA2F identified patients with PNF with 100% accuracy. This glycomarker was the only factor associated with PNF in multivariate analysis in the derivation and the validation sets (P < .0001). CONCLUSIONS: In an analysis of patients who underwent liver transplantation, we associated graft perfusate level of glycan NGA2F present on perfusate proteins with development of PNF with 100% accuracy, and validated this finding in a separate cohort of patients. This biomarker might be used to assess grafts before transplantation, especially when high-risk organs are under consideration.

Elevated donor plasminogen activator inhibitor-1 levels and the risk of primary graft dysfunction.

Primary graft dysfunction (PGD) following lung transplantation is associated with elevated recipient plasma levels of plasminogen activator inhibitor-1 (PAI-1) and the receptor for advanced glycation end products (RAGE). However, the significance of these biomarkers in the donor plasma is uncertain. We hypothesized that elevated donor plasma levels of PAI-1 and RAGE would be associated with recipient PGD. We carried out a prospective unmatched case-control study of double-lung transplant recipients between May 2014 and September 2015. We compared donor plasma levels of PAI-1 and RAGE using rank-sum tests and t tests, in 12 recipients who developed PGD grade 2 or 3 within 72 hours postoperatively with 13 recipients who did not. Recipients who developed PGD had higher donor plasma levels of PAI-1 than recipients who did not (median 2.7 ng/mL vs 1.4; P = .03). Recipients with PGD also had numerically higher donor plasma levels of RAGE than recipients without PGD, although this difference did not achieve statistical significance (median 1061 pg/mL vs 679; P = .12). Systemic inflammatory responses in the donor, as reflected by elevated plasma levels of PAI-1, may contribute to the risk of developing PGD. Rapid biomarker assessment of easily available plasma samples may assist in donor lung selection and risk stratification.

Peripheral Blood Gene Expression Changes Associated With Primary Graft Dysfunction After Lung Transplantation.

Recipient responses to primary graft dysfunction (PGD) after lung transplantation may have important implications to the fate of the allograft. We therefore evaluated longitudinal differences in peripheral blood gene expression in subjects with PGD. RNA expression was measured throughout the first transplant year in 106 subjects enrolled in the Clinical Trials in Organ Transplantation-03 study using a panel of 100 hypothesis-driven genes. PGD was defined as grade 3 in the first 72 posttransplant hours. Eighteen genes were differentially expressed over the first year based on PGD development, with significant representation from innate and adaptive immunity genes, with most differences identified very early after transplant. Sixteen genes were overexpressed in the blood of patients with PGD compared to those without PGD within 7 days of allograft reperfusion, with most transcripts encoding innate immune/inflammasome-related proteins, including genes previously associated with PGD. Thirteen genes were underexpressed in patients with PGD compared to those without PGD within 7 days of transplant, highlighted by T cell and adaptive immune regulation genes. Differences in gene expression present within 2 h of reperfusion and persist for days after transplant. Future investigation will focus on the long-term implications of these gene expression differences on the outcome of the allograft.

Postreperfusion microcirculatory derangements after liver transplantation: Relationship to hemodynamics, serum mediators, and outcome.

Despite the growing data supporting the role of microcirculation in regulating liver function, little of this knowledge has been translated into clinical practice. The aim of this study is to quantify hepatic microcirculation in vivo using sidestream dark field (SDF) imaging and correlate these findings with hepatic blood flow, hemodynamic parameters, and soluble mediators. Postreperfusion hepatic microcirculation was assessed using SDF imaging. Hepatic microcirculation measurements included functional sinusoidal density (cm/cm2 ), sinusoidal diameter (µm), red blood cell velocity (µm/second), volumetric blood flow (pl/second), and flow heterogeneity (FH) index. The serum concentrations of endothelin 1 (ET-1) and other inflammatory markers were analyzed with Luminex technology. Portal venous and hepatic artery flows were measured using a flowmeter. Twenty-eight patients undergoing cadaveric liver transplantations have been included in this study. Early allograft dysfunction (EAD) occurred in 7 (25%) patients and was associated with microcirculatory dysfunction. Low arterial and portal flow, high dose of inotropes, cold ischemia time, steatosis, and high ET-1 levels were all associated with impaired microcirculation. The time interval between portal venous and hepatic arterial reperfusion significantly correlated with the changes of the liver grafts' microcirculation. EAD patients tended to have higher serum levels of ET-1 on postoperative days 1, 2, 5, and 7 (all P < 0.01). Serum levels of ET-1 correlated significantly with microcirculation parameters. In conclusion, postreperfusion hepatic microcirculation is a determinant of organ dysfunction after liver reperfusion and could be used to identify very early patients at risk of EAD. Liver Transplantation 23 527-536 2017 AASLD.

Clinical significance of lactate clearance for the development of early allograft dysfunction and short-term prognosis in deceased donor liver transplantation.

This retrospective study evaluated lactate clearance (LC), measured at 6, 12, 18, and 24 hours after reperfusion, as a predictor of early allograft dysfunction (EAD) and short-term outcomes in patients receiving deceased donor liver transplantation. Of 181 transplant recipients, 44 (24.3%) developed EAD and had lower LCs than those who did not develop EAD. A receiver operating characteristic analysis showed that LC determined at 6 hours showed the highest area under curve value of 0.828 (95% confidence interval [CI]: 0.755-0.990) for predicting the development of EAD at a cutoff value of 25.8% with 76.7% sensitivity and 77.9% specificity. LC values that fell below the cutoff values were significantly associated with EAD in a multivariate analysis, with values at 6 hours having the highest adjusted odds ratio (11.891, 95% CI: 4.469-31.639). In-hospital and 6 month mortalities were higher in patients with LC values below the cutoffs compared with those above the cutoff values at each time point. Thus, LC calculated shortly after reperfusion of an allograft is significantly discriminative for the development of EAD and is associated with short-term prognosis after deceased donor liver transplantation.

Circulating Cell Death Biomarkers May Predict Survival in Human Lung Transplantation.

RATIONALE: Immediate graft performance after lung transplantation is associated with short- and long-term clinical outcomes. However, the biologic mechanism that determines outcomes is not fully understood. OBJECTIVES: To investigate the impact of cell death signals at 24 and 48 hours after lung transplantation on short- and long-term clinical outcomes. METHODS: Plasma samples were collected pretransplantation and at 24 and 48 hours after transplant from 60 bilateral lung transplant recipients. Ten patients had primary graft dysfunction (PGD) grade 3 (PaO2/FiO2 ratio <200 or on extracorporeal membrane oxygenation support) at 72 hours after transplant (PGD group). The remaining 50 patients were defined as the control group. Levels of plasma M30 (signifying epithelial apoptosis), M65 (signifying epithelial apoptosis plus necrosis), and high-mobility group box 1 protein (HMGB-1; signifying necrosis of all cell types) were measured by ELISA and correlated with clinical outcomes. Survival analyses were performed using Kaplan-Meier curves and Cox proportional hazards regression. Prediction accuracy of markers was assessed by calculated area under the curve of receiver operating characteristic graph. MEASUREMENTS AND MAIN RESULTS: The PGD group had significantly higher M30 and M65 levels at 24 and 48 hours after transplant compared with the control group. There was no significant difference in HMGB-1. Area under the curve for 1-year survival was 0.86, 0.93, and 0.51 for M30, M65, and HMGB-1 at 48 hours, respectively. Survival analysis showed that higher M30 and M65 levels at 24 and 48 hours were significantly associated with worse survival. M65 at 48 hours remained significant even after adjustment for PGD. HMGB-1 was not significantly associated with survival. CONCLUSIONS: Recipient plasma concentration of epithelial cell death markers (M30, M65) after lung transplantation is negatively correlated with early graft performance and long-term survival.

Role of the postoperative cholesterol in early allograft dysfunction and survival after living donor liver transplantation.

BACKGROUND: Many studies have confirmed that serum total cholesterol (sTC) concentrations were associated with underlying liver damage and the synthesis capacity of liver. However, the role of postoperative sTC level on evaluating graft function and predicting survival of recipients who underwent liver transplantation has not been discussed. METHODS: Clinical data of 231 living donor liver transplantation recipients from May 2003 to January 2015 were retrospectively collected. Patients were stratified into the low sTC group (sTC <1.42 mmol/L, 57 recipients) and high sTC group (sTC =1.42 mmol/L, 174 recipients) according the sTC level on postoperative day 3 based on receiver-operating characteristic curve analysis. The clinical characteristics and postoperative short- and long-term outcomes were compared between the two groups. RESULTS: Recipients with sTC <1.42 mmol/L experienced more severe preoperative disease conditions, a higher incidence of postoperative early allograft dysfunction (38.6% vs 10.3%, P<0.001), 90-day mortality (28.1% vs 10.9%, P=0.002) and severe complications (29.8% vs 17.2%, P=0.041) compared to recipients with sTC =1.42 mmol/L. The multivariate analysis demonstrated that sTC <1.42 mmol/L had a 4.08-fold (95% CI: 1.83-9.11, P=0.001) and 2.72-fold (95% CI: 1.23-6.00, P=0.013) greater risk of developing allograft dysfunction and 90-day mortality, and patients with sTC <1.42 mmol/L had poorer overall recipient and graft survival rates at 1-, 3-, and 5-year than those with sTC =1.42 mmol/L (67%, 61% and 61% vs 83%, 71% and 69%, P=0.025; 65%, 59% and 59% vs 81%, 68% and 66%, P=0.026, respectively). Cox multivariate analysis showed that sTC <1.42 mmol/L was an independent predicting factor for total recipient survival (HR=2.043; 95% CI: 1.173-3.560; P=0.012) and graft survival (HR=1.905; 95% CI: 1.115-3.255; P=0.018). CONCLUSIONS: sTC <1.42 mmol/L on postoperative day 3 was an independent risk factor of postoperative early allograft dysfunction, 90-day mortality, recipient and graft survival, which can be used as a marker for predicting postoperative short- and long-term outcomes.

Protein Quantitative Trait Loci Analysis Identifies Genetic Variation in the Innate Immune Regulator TOLLIP in Post-Lung Transplant Primary Graft Dysfunction Risk.

The authors previously identified plasma plasminogen activator inhibitor-1 (PAI-1) level as a quantitative lung injury biomarker in primary graft dysfunction (PGD). They hypothesized that plasma levels of PAI-1 used as a quantitative trait could facilitate discovery of genetic loci important in PGD pathogenesis. A two-stage cohort study was performed. In stage 1, they tested associations of loci with PAI-1 plasma level using linear modeling. Genotyping was performed using the Illumina CVD Bead Chip v2. Loci meeting a p < 5 × 10(-4) cutoff were carried forward and tested in stage 2 for association with PGD. Two hundred ninety-seven enrollees were evaluated in stage 1. Six loci, associated with PAI-1, were carried forward to stage 2 and evaluated in 728 patients. rs3168046 (Toll interacting protein [TOLLIP]) was significantly associated with PGD (p = 0.006). The increased risk of PGD for carrying at least one copy of this variant was 11.7% (95% confidence interval 4.9-18.5%). The false-positive rate for individuals with this genotype who did not have PGD was 6.1%. Variants in the TOLLIP gene are associated with higher circulating PAI-1 plasma levels and validate for association with clinical PGD. A protein quantitative trait analysis for PGD risk prioritizes genetic variations in TOLLIP and supports a role for Toll-like receptors in PGD pathogenesis.

Primary Graft Dysfunction and Mortality Following Lung Transplantation: A Role for Proadrenomedullin Plasma Levels.

Primary graft dysfunction (PGD) after lung transplantation (LT) is a heterogeneous syndrome that comprises clinical presentations with diverse grades of severity. Proadrenomedullin (proADM) levels may be associated with PGD and may enhance its relationship with outcomes. We prospectively included 100 LT recipients. Plasma levels of proADM were measured at 24, 48 and 72 h after admission to the intensive care unit (ICU). We assessed their relationship with PGD grade and ICU mortality. Fifty patients (50%) presented grade 3 PGD at ICU admission. Twenty-two patients (22%) developed grade 3 PGD at 72 h, the only grade associated with higher mortality (odds ratio 6.84, 95% confidence interval [CI] 1.47-38.44). ProADM levels measured at 24 h (3.25 vs. 1.61 nmol/L; p = 0.016) and 72 h (2.17 vs. 1.35 nmol/L; p = 0.011) were higher in these patients than the rest of the population. When we added the individual predictive utility of grade 3 PGD at 72 h for ICU mortality (area under the curve [AUC] 0.72, 95% CI 0.53-0.90) to that of ProADM at 72 h, the predictive value of the model improved (AUC 0.81, 95% CI 0.65-0.97). Higher levels of proADM measured following LT are associated with grade 3 PGD at 72 h. ProADM enhances the association of this entity with mortality.

Serum Neutrophil Gelatinase-Associated Lipocalin and Cystatin C for Assessing Recovery of Graft Function in Patients Undergoing Living-Donor Kidney Transplantation.

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) can be used as an early indicator of acute kidney injury (AKI), and cystatin C is also suggested to be an ideal marker of glomerular filtration rate (GFR), but they were not sufficiently studied in recipients without delayed graft function (DGF) after living-donor kidney transplant (LDKT). The aim of the study is to investigate whether serum NGAL and cystatin C can assess the recovery of renal function after LDKT. METHODS: 49 adult patients that had undergone LDKT between January 2012 and March 2014 were prospectively enrolled. Serum creatinine, NGAL, and cystatin C were measured on day 0-7, day 10, day 14 and month 9 after transplant. Recovery of graft function was evaluated by the time needed to reach eGFR > or = 60 mL/min/1.73 in2 Poor long-term graft outcome was defined as eGFR < 60 mL/min/1.73 M2 at 9 months. RESULTS: No DGF was recorded. Serum NGAL level decreased to normal earlier than creatinine after transplant. Cystatin C declined rapidly, but still stayed above the normal range. Serum NGAL on day 0 (p = 0.028) and cystatin C on day 2 (p < 0.001) were independent predictors of the time for graft function recovery in multivariate analysis. Compared to recipients with fair long-term graft outcome (eGFR > 60 mL/min/1.73 m2 at 9 months), recipients with poor long-term graft outcome (eGFR < 60 mL/min/1.73 m2 at 9 months) displayed higher serum NGAL on day 2 (p = 0.045), older age (p = 0.002), longer time on dialysis (p = 0.02), and lower donor eGFR (p = 0.045). There were correlations between serum NGAL and eGFR on day 0 and day 2. Correlations between serum cystatin C and eGFR on day 0, day 2, and month 9 were all significant. CONCLUSIONS: Serum NGAL may be used as an early predictor of recovery of post-transplant graft function after LDKT, but may not be used for real-time assessment of GFR. At the same time, the predictive ability of serum cystatin C needs to be further assessed.

Neutrophil extracellular traps are pathogenic in primary graft dysfunction after lung transplantation.

RATIONALE: Primary graft dysfunction (PGD) causes early mortality after lung transplantation and may contribute to late graft failure. No effective treatments exist. The pathogenesis of PGD is unclear, although both neutrophils and activated platelets have been implicated. We hypothesized that neutrophil extracellular traps (NETs) contribute to lung injury in PGD in a platelet-dependent manner. OBJECTIVES: To study NETs in experimental models of PGD and in lung transplant patients. METHODS: Two experimental murine PGD models were studied: hilar clamp and orthotopic lung transplantation after prolonged cold ischemia (OLT-PCI). NETs were assessed by immunofluorescence microscopy and ELISA. Platelet activation was inhibited with aspirin, and NETs were disrupted with DNaseI. NETs were also measured in bronchoalveolar lavage fluid and plasma from lung transplant patients with and without PGD. MEASUREMENTS AND MAIN RESULTS: NETs were increased after either hilar clamp or OLT-PCI compared with surgical control subjects. Activation and intrapulmonary accumulation of platelets were increased in OLT-PCI, and platelet inhibition reduced NETs and lung injury, and improved oxygenation. Disruption of NETs by intrabronchial administration of DNaseI also reduced lung injury and improved oxygenation. In bronchoalveolar lavage fluid from human lung transplant recipients, NETs were more abundant in patients with PGD. CONCLUSIONS: NETs accumulate in the lung in both experimental and clinical PGD. In experimental PGD, NET formation is platelet-dependent, and disruption of NETs with DNaseI reduces lung injury. These data are the first description of a pathogenic role for NETs in solid organ transplantation and suggest that NETs are a promising therapeutic target in PGD.

Early allograft dysfunction after liver transplantation: an intermediate outcome measure for targeted improvements.

BACKGROUND: The term early allograft dysfunction (EAD) identifies liver transplant (LT) allografts with initial poor function and portends poor allograft and patient survival. Aims of this study are to use EAD as an intermediate outcome measure in a large single center cohort and identify donor, recipient and peri-operative risk factors. MATERIAL AND METHODS: In 1950 consecutive primary LT, donor, recipient and peri-operative data were collected. EAD was defined by the presence of one or more of the following: total bilirubin ≥ 10 mg/dL (171 µmol/L) or, INR ≥ 1.6 on day 7, and ALT/AST > 2,000 IU/L within the first 7 days. RESULTS: The incidence of EAD was 26.5%. 1-, 3-, and 5-year allograft and patient survival for patients who developed EAD were significantly inferior to those who did not (P < 0.01 at all time points). Multivariate analysis demonstrated associations in the development of EAD with recipient pre-operative ventilator status, donation after cardiac death allografts, donor age, allograft size, degree of steatosis, operative time and intra-operative transfusion requirements (all P < 0.01). Patients with EAD had a significantly longer hospitalization at 20.9 ± 38.9 days (median: 9; range: 4-446) compared with 10.7 ± 13.5 days (median: 7; range: 3-231) in patients with no EAD (P < 0.01). CONCLUSIONS: This is the largest single center experience demonstrating incidence of EAD and identifying factors associated with development of EAD. EAD is a useful intermediate outcome measure for allograft and patient survival. Balancing recipient pretransplant conditions, donor risk factors and intra-operative conditions are necessary for avoiding EAD.

A score model for the continuous grading of early allograft dysfunction severity.

Early allograft dysfunction (EAD) dramatically influences graft and patient outcomes. A lack of consensus on an EAD definition hinders comparisons of liver transplant outcomes and management of recipients among and within centers. We sought to develop a model for the quantitative assessment of early allograft function [Model for Early Allograft Function Scoring (MEAF)] after transplantation. A retrospective study including 1026 consecutive liver transplants was performed for MEAF score development. Multivariate data analysis was used to select a small number of postoperative variables that adequately describe EAD. Then, the distribution of these variables was mathematically modeled to assign a score for each actual variable value. A model, based on easily obtainable clinical parameters (ie, alanine aminotransferase, international normalized ratio, and bilirubin) and scoring liver function from 0 to 10, was built. The MEAF score showed a significant association with patient and graft survival at 3-, 6- and 12-month follow-ups. Hepatic steatosis and age for donors; cold/warm ischemia times and postreperfusion syndrome for surgery; and intensive care unit and hospital stays, Model for End-Stage Liver Disease and Child-Pugh scores, body mass index, and fresh frozen plasma transfusions for recipients were factors associated significantly with EAD. The model was satisfactorily validated by its application to an independent set of 200 patients who underwent liver transplantation at a different center. In conclusion, a model for the quantitative assessment of EAD severity has been developed and validated for the first time. The MEAF provides a more accurate graft function assessment than current categorical classifications and may help clinicians to make early enough decisions on retransplantation benefits. Furthermore, the MEAF score is a predictor of recipient and graft survival. The standardization of the criteria used to define EAD may allow reliable comparisons of recipients' treatments and transplant outcomes among and within centers.

Genetic variation in the prostaglandin E2 pathway is associated with primary graft dysfunction.

RATIONALE: Biologic pathways with significant genetic conservation across human populations have been implicated in the pathogenesis of primary graft dysfunction (PGD). The evaluation of the role of recipient genetic variation in PGD has thus far been limited to single, candidate gene analyses. OBJECTIVES: We sought to identify genetic variants in lung transplant recipients that are responsible for increased risk of PGD using a two-phase large-scale genotyping approach. METHODS: Phase 1 was a large-scale candidate gene association study of the multicenter, prospective Lung Transplant Outcomes Group cohort. Phase 2 included functional evaluation of selected variants and a bioinformatics screening of variants identified in phase 1. MEASUREMENTS AND MAIN RESULTS: After genetic data quality control, 680 lung transplant recipients were included in the analysis. In phase 1, a total of 17 variants were significantly associated with PGD, four of which were in the prostaglandin E2 family of genes. Among these were a coding variant in the gene encoding prostaglandin E2 synthase (PTGES2; P = 9.3 × 10(-5)) resulting in an arginine to histidine substitution at amino acid position 298, and three variants in a block containing the 5' promoter and first intron of the PTGER4 gene (encoding prostaglandin E2 receptor subtype 4; all P < 5 × 10(-5)). Functional evaluation in regulatory T cells identified that rs4434423A in the PTGER4 gene was associated with differential suppressive function of regulatory T cells. CONCLUSIONS: Further research aimed at replication and additional functional insight into the role played by genetic variation in prostaglandin E2 synthetic and signaling pathways in PGD is warranted.

Preoperative plasma club (clara) cell secretory protein levels are associated with primary graft dysfunction after lung transplantation.

Inherent recipient factors, including pretransplant diagnosis, obesity and elevated pulmonary pressures, are established primary graft dysfunction (PGD) risks. We evaluated the relationship between preoperative lung injury biomarkers and PGD to gain further mechanistic insight in recipients. We performed a prospective cohort study of recipients in the Lung Transplant Outcomes Group enrolled between 2002 and 2010. Our primary outcome was Grade 3 PGD on Day 2 or 3. We measured preoperative plasma levels of five biomarkers (CC-16, sRAGE, ICAM-1, IL-8 and Protein C) that were previously associated with PGD when measured at the postoperative time point. We used multivariable logistic regression to adjust for potential confounders. Of 714 subjects, 130 (18%) developed PGD. Median CC-16 levels were elevated in subjects with PGD (10.1 vs. 6.0, p<0.001). CC-16 was associated with PGD in nonidiopathic pulmonary fibrosis (non-IPF) subjects (OR for highest quartile of CC-16: 2.87, 95% CI: 1.37, 6.00, p=0.005) but not in subjects with IPF (OR 1.38, 95% CI: 0.43, 4.45, p=0.59). After adjustment, preoperative CC-16 levels remained associated with PGD (OR: 3.03, 95% CI: 1.26, 7.30, p=0.013) in non-IPF subjects. Our study suggests the importance of preexisting airway epithelial injury in PGD. Markers of airway epithelial injury may be helpful in pretransplant risk stratification in specific recipients.