Publications by authors named "David J Ross"

58 Publications

Donor-derived, cell-free DNA levels by next-generation targeted sequencing are elevated in allograft rejection after lung transplantation.

ERJ Open Res 2021 Jan 25;7(1). Epub 2021 Jan 25.

Division of Pulmonary and Critical Care Medicine, Dept of Medicine, Stanford University, Stanford, CA, USA.

Surveillance after lung transplantation is critical to the detection of acute cellular rejection (ACR) and prevention of chronic lung allograft dysfunction (CLAD). Therefore, we measured donor-derived cell-free DNA (dd-cfDNA) implementing a clinical-grade, next-generation targeted sequencing assay in 107 plasma samples from 38 unique lung transplantation recipients with diagnostic cohorts classified as: (1) biopsy-confirmed or treated ACR, (2) antibody-mediated rejection (AMR), (3) obstructive CLAD, (4) allograft infection (INFXN) and (5) Stable healthy allografts (STABLE). Our principal findings are as follows: (1) dd-cfDNA level was elevated in ACR (median 0.91%; interquartile range (IQR): 0.39-2.07%), CLAD (2.06%; IQR: 0.57-3.67%) and an aggregated cohort of rejection encompassing allograft injury (1.06%; IQR: 0.38-2.51%), compared with the STABLE cohort (0.38%; IQR: 0.23-0.87%) (p=0.02); (2) dd-cfDNA level with AMR was elevated (1.34%; IQR: 0.34-2.40%) compared to STABLE, although it did not reach statistical significance (p=0.07) due to limitations in sample size; (3) there was no difference in dd-cfDNA for allograft INFXN (0.39%; IQR: 0.18-0.67%) STABLE, which may relate to differences in "tissue injury" with the spectrum of bronchial colonisation invasive infection; (4) there was no difference for dd-cfDNA in unilateral bilateral lung transplantation; (5) "optimal threshold" for dd-cfDNA for aggregated rejection events representing allograft injury was determined as 0.85%, with sensitivity=55.6%, specificity=75.8%, positive predictive value (PPV)=43.3% and negative predictive value (NPV)=83.6%. Measurement of plasma dd-cfDNA may be a clinically useful tool for the assessment of lung allograft health and surveillance for "tissue injury" with a spectrum of rejection.
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http://dx.doi.org/10.1183/23120541.00462-2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7836440PMC
January 2021

Remote monitoring using donor-derived, cell-free DNA after kidney transplantation during the coronavirus disease 2019 pandemic.

Kidney Res Clin Pract 2020 Dec;39(4):495-500

Medical Affairs, CareDx Inc., Brisbane, CA, USA.

Background: Donor-derived, cell-free DNA (dd-cfDNA) level correlates with allograft injury with clinical validity and utility for quiescence and active acute rejection (AR) in kidney transplant recipients. We analyzed trends in dd-cfDNA level immediately preceding and during the coronavirus disease 2019 (COVID-19) pandemic with implemented "shelter in place" and a tele-health strategy with remote home phlebotomy to limit COVID-19 exposure.

Methods: During COVID-19 in the United States (US), we surveyed weekly (January 6, 2020-May 25, 2020) metrics for dd-cfDNA corresponding to both a low risk for active rejection (dd-cfDNA < 0.5%) and cohorts with indeterminate levels of 0.5% to 1.0% and > 1.0%. During the study timeframe, over 11,000 patient samples (67%) from 150 kidney transplantation centers were transitioned from standard facility-based to remote phlebotomy.

Results: The proportion of dd-cfDNA samples, analyzed in 21 weekly aggregated cohorts by risk-stratification category, was unchanged during the COVID-19 escalation in the US. Linearized slopes for numbers of samples corresponding to indeterminate risk for AR cohorts of > 1.0% and 0.5% to 1.0% were -0.31 and -0.12, respectively; indicating that prevalence of these "at risk for AR cohorts" decreased during remote surveillance. Approximately 73% of samples corresponded to low risk of AR (dd-cfDNA < 0.5%), while an additional 15% of samples had dd-cfDNA level ≤ 1.0%.

Conclusion: The combination of remote home phlebotomy including dd-cfDNA analysis and a tele-health program offer a new paradigm that may substantially improve patient compliance and assuage anxiety regarding the state of kidney allograft health during the COVID-19 pandemic. Further prospective multi-center studies with robust outcomes data are warranted.
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http://dx.doi.org/10.23876/j.krcp.20.107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7770990PMC
December 2020

Plasma Donor-derived Cell-free DNA Levels Are Increased During Acute Cellular Rejection After Lung Transplant: Pilot Data.

Transplant Direct 2020 Oct 24;6(10):e608. Epub 2020 Sep 24.

David Geffen-UCLA School of Medicine, CareDx, Inc., Los Angeles, CA.

Telehealth platforms with remote phlebotomy and biomarker implementation represent a novel paradigm for surveillance after lung transplantation (LT). In a pilot study, we investigated donor-derived cell-free DNA (dd-cfDNA) in plasma using a clinical-grade "next-generation sequencing" assay.

Methods: dd-cfDNA levels determined in biorepository venous plasma samples obtained during the lung allograft rejection gene expression observation study, implementing a clinical-grade next-generation sequencing assay. Sixty-nine unique LT patients encompassing 9 LT centers, with associated clinical-histopathologic diagnoses, were examined-allograft infection (n = 26), normal histopathology without infection (n = 30), and acute cellular rejection (ACR; n = 13).

Results: dd-cfDNA in ACR patients were significantly elevated (1.52%; interquartile range [IQR], 0.520-2.2550) compared with the normal stable patients (0.485%; IQR, 0.220-0.790) ( = 0.026). During allograft infection, dd-cfDNA values were not different (0.595; IQR, 0.270-1.170) from normal ( = 0.282) and ACR ( = 0.100). AUC-receiver operator characteristics curve analysis for allograft ACR was 0.717 (95% confidence interval, 0.547-0.887;  = 0.025). At a 0.87% threshold dd-cfDNA-sensitivity = 73.1%, specificity = 52.9%, positive predictive value = 34.1%, and negative predictive value = 85.5%.

Conclusions: dd-cfDNA assessment holds promise as a noninvasive biomarker of "allograft injury" with acute rejection following LT while prospective, multicenter studies should further refine utility across the spectrum of allograft rejection and infection.
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http://dx.doi.org/10.1097/TXD.0000000000001063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7515612PMC
October 2020

Single Center "Snapshot" Experience With Donor-Derived Cell-Free DNA After Lung Transplantation.

Biomark Insights 2020 16;15:1177271920958704. Epub 2020 Sep 16.

Department of Cardiothoracic Surgery, University of Texas Health Science Center San Antonio, San Antonio, TX, USA.

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http://dx.doi.org/10.1177/1177271920958704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7498978PMC
September 2020

Capillary Proliferation in Systemic-Sclerosis-Related Pulmonary Fibrosis: Association with Pulmonary Hypertension.

ACR Open Rheumatol 2019 Mar 15;1(1):26-36. Epub 2019 Mar 15.

University of California Los Angeles.

Objective: We sought to determine if any histopathologic component of the pulmonary microcirculation can distinguish systemic sclerosis (SSc)-related pulmonary fibrosis (PF) with and without pulmonary hypertension (PH).

Methods: Two pulmonary pathologists blindly evaluated 360 histologic slides from lungs of 31 SSc-PF explants or autopsies with (n = 22) and without (n = 9) PH. The presence of abnormal small arteries, veins, and capillaries (pulmonary microcirculation) was semiquantitatively assessed in areas of preserved lung architecture. Capillary proliferation (CP) within the alveolar walls was measured by its distribution, extent (CP % involvement), and maximum number of layers (maximum CP). These measures were then evaluated to determine the strength of their association with right heart catheterization-proven PH.

Results: Using consensus measures, all measures of CP were significantly associated with PH. Maximum CP had the strongest association with PH ( = 0.013; C statistic 0.869). Maximum CP 2 or more layers and CP % involvement 10% or greater were the optimal thresholds that predicted PH, both with a sensitivity of 56% and specificity of 91%. The CP was typically multifocal rather than focal or diffuse and was associated with a background pattern of usual interstitial pneumonia. There was a significant but weaker relationship between the presence of abnormal small arteries and veins and PH.

Conclusion: In the setting of advanced SSc-PF, the histopathologic feature of the pulmonary microcirculation best associated with PH was capillary proliferation in architecturally preserved lung areas.
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http://dx.doi.org/10.1002/acr2.1003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6858021PMC
March 2019

Mitochondrial DNA Stimulates TLR9-Dependent Neutrophil Extracellular Trap Formation in Primary Graft Dysfunction.

Am J Respir Cell Mol Biol 2020 03;62(3):364-372

Department of Medicine.

The immune system is designed to robustly respond to pathogenic stimuli but to be tolerant to endogenous ligands to not trigger autoimmunity. Here, we studied an endogenous damage-associated molecular pattern, mitochondrial DNA (mtDNA), during primary graft dysfunction (PGD) after lung transplantation. We hypothesized that cell-free mtDNA released during lung ischemia-reperfusion triggers neutrophil extracellular trap (NET) formation via TLR9 signaling. We found that mtDNA increases in the BAL fluid of experimental PGD (prolonged cold ischemia followed by orthotopic lung transplantation) and not in control transplants with minimal warm ischemia. The adoptive transfer of mtDNA into the minimal warm ischemia graft immediately before lung anastomosis induces NET formation and lung injury. TLR9 deficiency in neutrophils prevents mtDNA-induced NETs, and TLR9 deficiency in either the lung donor or recipient decreases NET formation and lung injury in the PGD model. Compared with human lung transplant recipients without PGD, severe PGD was associated with high levels of BAL mtDNA and NETs, with evidence of relative deficiency in DNaseI. We conclude that mtDNA released during lung ischemia-reperfusion triggers TLR9-dependent NET formation and drives lung injury. In PGD, DNaseI therapy has a potential dual benefit of neutralizing a major NET trigger (mtDNA) in addition to dismantling pathogenic NETs.
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http://dx.doi.org/10.1165/rcmb.2019-0140OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7055700PMC
March 2020

Usefulness of gene expression profiling of bronchoalveolar lavage cells in acute lung allograft rejection.

J Heart Lung Transplant 2019 08 7;38(8):845-855. Epub 2019 May 7.

Departments of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA.

Background: Chronic lung allograft dysfunction (CLAD) is the main limitation to long-term survival after lung transplantation. Because effective therapies are lacking, early identification and mitigation of risk factors is a pragmatic approach to improve outcomes. Acute cellular rejection (ACR) is the most pervasive risk factor for CLAD, but diagnosis requires transbronchial biopsy, which carries risks. We hypothesized that gene expression in the bronchoalveolar lavage (BAL) cell pellet (CP) could replace biopsy and inform on mechanisms of CLAD.

Methods: We performed RNA sequencing on BAL CPs from 219 lung transplant recipients with A-grade ACR (n = 61), lymphocytic bronchiolitis (n = 58), infection (n = 41), or no rejection/infection (n = 59). Differential gene expression was based on absolute fold difference >2.0 and Benjamini-adjusted p-value ≤0.05. We used the Database for Annotation, Visualization and Integrated Discovery Bioinformatics Resource for pathway analyses. For classifier modeling, samples were randomly split into training (n = 154) and testing sets (n = 65). A logistic regression model using recursive feature elimination and 5-fold cross-validation was trained to optimize area under the curve (AUC).

Results: Differential gene expression identified 72 genes. Enriched pathways included T-cell receptor signaling, natural killer cell-mediated cytotoxicity, and cytokine-cytokine receptor interaction. A 4-gene model (AUC = 0.72) and classification threshold defined in the training set exhibited fair performance in the testing set; accuracy was 76%, specificity 82%, and sensitivity 60%. In addition, classification as ACR was associated with worse CLAD-free survival (hazard ratio = 2.42; 95% confidence interval = 1.29-4.53).

Conclusions: BAL CP gene expression during ACR is enriched for immune response pathways and shows promise as a diagnostic tool for ACR, especially ACR that is a precursor of CLAD.
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http://dx.doi.org/10.1016/j.healun.2019.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6663624PMC
August 2019

BOLA (BolA Family Member 3) Deficiency Controls Endothelial Metabolism and Glycine Homeostasis in Pulmonary Hypertension.

Circulation 2019 05;139(19):2238-2255

Center for Pulmonary Vascular Biology and Medicine, Center for Metabolism and Mitochondrial Medicine, Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Division of Cardiology and Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, PA (Q.Y., Y.-Y.T., Y.T., J.Z., V.N., M.K.C., J.P., W.S., J.S., M.R., M.S., N.K., T.S., M.Z., N.F., S.S., S.Y.C.).

Background: Deficiencies of iron-sulfur (Fe-S) clusters, metal complexes that control redox state and mitochondrial metabolism, have been linked to pulmonary hypertension (PH), a deadly vascular disease with poorly defined molecular origins. BOLA3 (BolA Family Member 3) regulates Fe-S biogenesis, and mutations in BOLA3 result in multiple mitochondrial dysfunction syndrome, a fatal disorder associated with PH. The mechanistic role of BOLA3 in PH remains undefined.

Methods: In vitro assessment of BOLA3 regulation and gain- and loss-of-function assays were performed in human pulmonary artery endothelial cells using siRNA and lentiviral vectors expressing the mitochondrial isoform of BOLA3. Polymeric nanoparticle 7C1 was used for lung endothelium-specific delivery of BOLA3 siRNA oligonucleotides in mice. Overexpression of pulmonary vascular BOLA3 was performed by orotracheal transgene delivery of adeno-associated virus in mouse models of PH.

Results: In cultured hypoxic pulmonary artery endothelial cells, lung from human patients with Group 1 and 3 PH, and multiple rodent models of PH, endothelial BOLA3 expression was downregulated, which involved hypoxia inducible factor-2α-dependent transcriptional repression via histone deacetylase 1-mediated histone deacetylation. In vitro gain- and loss-of-function studies demonstrated that BOLA3 regulated Fe-S integrity, thus modulating lipoate-containing 2-oxoacid dehydrogenases with consequent control over glycolysis and mitochondrial respiration. In contexts of siRNA knockdown and naturally occurring human genetic mutation, cellular BOLA3 deficiency downregulated the glycine cleavage system protein H, thus bolstering intracellular glycine content. In the setting of these alterations of oxidative metabolism and glycine levels, BOLA3 deficiency increased endothelial proliferation, survival, and vasoconstriction while decreasing angiogenic potential. In vivo, pharmacological knockdown of endothelial BOLA3 and targeted overexpression of BOLA3 in mice demonstrated that BOLA3 deficiency promotes histological and hemodynamic manifestations of PH. Notably, the therapeutic effects of BOLA3 expression were reversed by exogenous glycine supplementation.

Conclusions: BOLA3 acts as a crucial lynchpin connecting Fe-S-dependent oxidative respiration and glycine homeostasis with endothelial metabolic reprogramming critical to PH pathogenesis. These results provide a molecular explanation for the clinical associations linking PH with hyperglycinemic syndromes and mitochondrial disorders. These findings also identify novel metabolic targets, including those involved in epigenetics, Fe-S biogenesis, and glycine biology, for diagnostic and therapeutic development.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.118.035889DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6519484PMC
May 2019

Augmented concentrations of CX3CL1 are associated with interstitial lung disease in systemic sclerosis.

PLoS One 2018 20;13(11):e0206545. Epub 2018 Nov 20.

Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.

Background: Dysregulation of Fractalkine (CX3CL1) and its receptor CX3CR1 has been linked to the pathobiology of chronic inflammatory conditions. We explored CX3CL1 in systemic sclerosis (SSc) related progressive interstitial lung disease (ILD) and pulmonary hypertension (PH) in two different but complementary sources of biomaterial.

Methods: We collected lung tissue at the time of lung transplantation at UCLA from SSc-ILD patients (n = 12) and healthy donors (n = 12); and serum samples from the prospective Oslo University Hospital SSc cohort (n = 292) and healthy donors (n = 100). CX3CL1 was measured by ELISA. Cellular sources of CX3CL1/CX3CR1 in lung tissues were determined by immunohistochemistry and immunofluorescence. ILD progression and new onset PH endpoints were analysed.

Results: CX3CL1 concentrations were increased in SSc in lung tissue as well as in sera. In the UCLA cohort, CX3CL1 was highly correlated with DLCO. In the SSc-ILD lungs, CX3CL1 was identified in reactive type II pneumocytes and airway epithelial cells. CX3CR1 stained infiltrating interstitial mononuclear cells, especially plasma cells. In the Oslo cohort, CX3CL1 correlated with anti-Topoisomerase-I-antibody and lung fibrosis. CX3CL1 was associated with ILD progression in multivariable regression analysis but not PH.

Conclusion: CX3CL1 is associated with progressive SSc-ILD but not SSc-PH. The CX3CR1/CX3CL1-biological axis may be involved in recruiting antibody secreting plasma cells to SSc lungs, thereby contributing to the immune-mediated pathobiology of SSc-ILD.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0206545PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6245508PMC
April 2019

Pulmonary Allograft Versus Host Disease.

Transplant Direct 2017 Dec 20;3(12):e333. Epub 2017 Nov 20.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA.

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http://dx.doi.org/10.1097/TXD.0000000000000749DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828692PMC
December 2017

The Impact of Allograft CXCL9 during Respiratory Infection on the Risk of Chronic Lung Allograft Dysfunction.

OBM Transplant 2018 30;2(4). Epub 2018 Nov 30.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1690, USA.

Background: The long term clinical significance of respiratory infections after lung transplantation remains uncertain.

Methods: In this retrospective single-center cohort study of 441 lung transplant recipients, we formally evaluate the association between respiratory infection and chronic lung allograft dysfunction (CLAD). We furthermore hypothesized that bronchoalveolar lavage fluid (BALF) CXCL9 concentrations are augmented during respiratory infections, and that episodes of infection with elevated BALF CXCL9 are associated with greater CLAD risk.

Results: In univariable and multivariable models adjusted for other histopathologic injury patterns, respiratory infection, regardless of the causative organism, was a strong predictor of CLAD development (adjusted HR 1.8 95% CI 1.3-2.6). Elevated BALF CXCL9 concentrations during respiratory infections markedly increased CLAD risk in a dose-response manner. An episode of respiratory infection with CXCL9 concentrations greater than the 25, 50, and 75 percentile had adjusted HRs for CLAD of 1.8 (95% CI 1.1-2.8), 2.4 (95% CI 1.4-4.0) and 4.4 (95% CI 2.4-8.0), respectively.

Conclusions: Thus, we demonstrate that respiratory infections, regardless of the causative organism, are strong predictors of CLAD development. We furthermore demonstrate for the first time, the prognostic importance of BALF CXCL9 concentrations during respiratory infections on the risk of subsequent CLAD development.
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http://dx.doi.org/10.21926/obm.transplant.1804029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6693350PMC
November 2018

Gene Expression Profiling of Bronchoalveolar Lavage Cells During Aspergillus Colonization of the Lung Allograft.

Transplantation 2018 06;102(6):986-993

Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA.

Background: Aspergillus colonization after lung transplant is associated with an increased risk of chronic lung allograft dysfunction (CLAD). We hypothesized that gene expression during Aspergillus colonization could provide clues to CLAD pathogenesis.

Methods: We examined transcriptional profiles in 3- or 6-month surveillance bronchoalveolar lavage fluid cell pellets from recipients with Aspergillus fumigatus colonization (n = 12) and without colonization (n = 10). Among the Aspergillus colonized, we also explored profiles in those who developed CLAD (n = 6) or remained CLAD-free (n = 6). Transcription profiles were assayed with the HG-U133 Plus 2.0 microarray (Affymetrix). Differential gene expression was based on an absolute fold difference of 2.0 or greater and unadjusted P value less than 0.05. We used NIH Database for Annotation, Visualization and Integrated Discovery for functional analyses, with false discovery rates less than 5% considered significant.

Results: Aspergillus colonization was associated with differential expression of 489 probe sets, representing 404 unique genes. "Defense response" genes and genes in the "cytokine-cytokine receptor" Kyoto Encyclopedia of Genes and Genomes pathway were notably enriched in this list. Among Aspergillus colonized patients, CLAD development was associated with differential expression of 69 probe sets, representing 64 unique genes. This list was enriched for genes involved in "immune response" and "response to wounding", among others. Notably, both chitinase 3-like-1 and chitotriosidase were associated with progression to CLAD.

Conclusions: Aspergillus colonization is associated with gene expression profiles related to defense responses including cytokine signaling. Epithelial wounding, as well as the innate immune response to chitin that is present in the fungal cell wall, may be key in the link between Aspergillus colonization and CLAD.
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http://dx.doi.org/10.1097/TP.0000000000002058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5962368PMC
June 2018

The prognostic importance of CXCR3 chemokine during organizing pneumonia on the risk of chronic lung allograft dysfunction after lung transplantation.

PLoS One 2017 7;12(7):e0180281. Epub 2017 Jul 7.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.

Rationale: Since the pathogenesis of chronic lung allograft dysfunction (CLAD) remains poorly defined with no known effective therapies, the identification and study of key events which increase CLAD risk is a critical step towards improving outcomes. We hypothesized that bronchoalveolar lavage fluid (BALF) CXCR3 ligand concentrations would be augmented during organizing pneumonia (OP) and that episodes of OP with marked chemokine elevations would be associated with significantly higher CLAD risk.

Methods: All transbronchial biopsies (TBBX) from patients who received lung transplantation between 2000 to 2010 were reviewed. BALF concentrations of the CXCR3 ligands (CXCL9, CXCL10 and CXCL11) were compared between episodes of OP and "healthy" biopsies using linear mixed-effects models. The association between CXCR3 ligand concentrations during OP and CLAD risk was evaluated using proportional hazards models with time-dependent covariates.

Results: There were 1894 bronchoscopies with TBBX evaluated from 441 lung transplant recipients with 169 (9%) episodes of OP and 907 (49%) non-OP histopathologic injuries. 62 (37%) episodes of OP were observed during routine surveillance bronchoscopy. Eight hundred thirty-eight (44%) TBBXs had no histopathology and were classified as "healthy" biopsies. There were marked elevations in BALF CXCR3 ligand concentrations during OP compared with "healthy" biopsies. In multivariable models adjusted for other injury patterns, OP did not significantly increase the risk of CLAD when BAL CXCR3 chemokine concentrations were not taken into account. However, OP with elevated CXCR3 ligands markedly increased CLAD risk in a dose-response manner. An episode of OP with CXCR3 concentrations greater than the 25th, 50th and 75th percentiles had HRs for CLAD of 1.5 (95% CI 1.0-2.3), 1.9 (95% CI 1.2-2.8) and 2.2 (95% CI 1.4-3.4), respectively.

Conclusions: This study identifies OP, a relatively uncommon histopathologic finding after lung transplantation, as a major risk factor for CLAD development when considered in the context of increased allograft expression of interferon-γ inducible ELR- CXC chemokines. We further demonstrate for the first time, the prognostic importance of BALF CXCR3 ligand concentrations during OP on subsequent CLAD risk.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180281PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5501470PMC
September 2017

Gene Expression Profiling of Bronchoalveolar Lavage Cells Preceding a Clinical Diagnosis of Chronic Lung Allograft Dysfunction.

PLoS One 2017 19;12(1):e0169894. Epub 2017 Jan 19.

Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America.

Background: Chronic Lung Allograft Dysfunction (CLAD) is the main limitation to long-term survival after lung transplantation. Although CLAD is usually not responsive to treatment, earlier identification may improve treatment prospects.

Methods: In a nested case control study, 1-year post transplant surveillance bronchoalveolar lavage (BAL) fluid samples were obtained from incipient CLAD (n = 9) and CLAD free (n = 8) lung transplant recipients. Incipient CLAD cases were diagnosed with CLAD within 2 years, while controls were free from CLAD for at least 4 years following bronchoscopy. Transcription profiles in the BAL cell pellets were assayed with the HG-U133 Plus 2.0 microarray (Affymetrix). Differential gene expression analysis, based on an absolute fold change (incipient CLAD vs no CLAD) >2.0 and an unadjusted p-value ≤0.05, generated a candidate list containing 55 differentially expressed probe sets (51 up-regulated, 4 down-regulated).

Results: The cell pellets in incipient CLAD cases were skewed toward immune response pathways, dominated by genes related to recruitment, retention, activation and proliferation of cytotoxic lymphocytes (CD8+ T-cells and natural killer cells). Both hierarchical clustering and a supervised machine learning tool were able to correctly categorize most samples (82.3% and 94.1% respectively) into incipient CLAD and CLAD-free categories.

Conclusions: These findings suggest that a pathobiology, similar to AR, precedes a clinical diagnosis of CLAD. A larger prospective investigation of the BAL cell pellet transcriptome as a biomarker for CLAD risk stratification is warranted.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0169894PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5245825PMC
August 2017

Voriconazole increases the risk for cutaneous squamous cell carcinoma after lung transplantation.

Transpl Int 2017 Jan 24;30(1):41-48. Epub 2016 Oct 24.

Department of Medicine, University of California, Los Angeles, CA, USA.

Lung transplant recipients (LTR) are at high risk of cutaneous squamous cell carcinoma (SCC). Voriconazole exposure after lung transplant has recently been reported as a risk factor for SCC. We sought to study the relationship between fungal prophylaxis with voriconazole and the risk of SCC in sequential cohorts from a single center. We evaluated 400 adult LTR at UCLA between 7/1/2005 and 12/22/2012. On 7/1/2009, our center instituted a protocol switch from targeted to universal antifungal prophylaxis for at least 6 months post-transplant. Using Cox proportional hazards models, time to SCC was compared between targeted (N = 199) and universal (N = 201) prophylaxis cohorts. Cox models were also used to assess SCC risk as a function of time-dependent cumulative exposure to voriconazole and other antifungal agents. The risk of SCC was greater in the universal prophylaxis cohort (HR 2.02, P < 0.01). Voriconazole exposure was greater in the universal prophylaxis cohort, and the cumulative exposure to voriconazole was associated with SCC (HR 1.75, P < 0.01), even after adjustment for other important SCC risk factors. Voriconazole did not increase the risk of advanced tumors. Exposure to other antifungal agents was not associated with SCC. Voriconazole should be used cautiously in this population.
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http://dx.doi.org/10.1111/tri.12865DOI Listing
January 2017

Graft Loss and CLAD-Onset Is Hastened by Viral Pneumonia After Lung Transplantation.

Transplantation 2016 Nov;100(11):2424-2431

1 Division of Infectious Diseases, Department of Medicine, University of California Los Angeles, Los Angeles, CA. 2 Department of Medicine Statistics Core, University of California Los Angeles, Los Angeles, CA. 3 Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, CA. 4 Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California Los Angeles, Los Angeles, CA. 5 Division of Cardiothoracic Surgery, Department of Surgery, University of California Los Angeles.

Background: Community-acquired respiratory virus (CARV) infections occur frequently after lung transplantation and may adversely impact outcomes. We hypothesized that while asymptomatic carriage would not increase the risk of chronic lung allograft dysfunction (CLAD) and graft loss, severe infection would.

Methods: All lung transplant cases between January 2000 and July 2013 performed at our center were reviewed for respiratory viral samples. Each isolation of virus was classified according to clinical level of severity: asymptomatic, symptomatic without pneumonia, and viral pneumonia. Multivariate Cox modeling was used to assess the impact of CARV isolation on progression to CLAD and graft loss.

Results: Four thousand four hundred eight specimens were collected from 563 total patients, with 139 patients producing 324 virus-positive specimens in 245 episodes of CARV infection. Overall, the risk of CLAD was elevated by viral infection (hazard ratio [HR], 1.64; P < 0.01). This risk, however, was due to viral pneumonia alone (HR, 3.94; P < 0.01), without significant impact from symptomatic viral infection (HR, 0.97; P = 0.94) nor from asymptomatic viral infection (HR, 0.99; P = 0.98). The risk of graft loss was not increased by asymptomatic CARV infection (HR, 0.74; P = 0.37) nor symptomatic CARV infection (HR, 1.39; P = 0.41). Viral pneumonia did, however, significantly increase the risk of graft loss (HR, 2.78; P < 0.01).

Conclusions: With respect to CARV, only viral pneumonia increased the risk of both CLAD and graft loss after lung transplantation. In the absence of pneumonia, respiratory viruses had no impact on measured outcomes.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5077663PMC
http://dx.doi.org/10.1097/TP.0000000000001346DOI Listing
November 2016

Vascular stiffness mechanoactivates YAP/TAZ-dependent glutaminolysis to drive pulmonary hypertension.

J Clin Invest 2016 09 22;126(9):3313-35. Epub 2016 Aug 22.

Dysregulation of vascular stiffness and cellular metabolism occurs early in pulmonary hypertension (PH). However, the mechanisms by which biophysical properties of the vascular extracellular matrix (ECM) relate to metabolic processes important in PH remain undefined. In this work, we examined cultured pulmonary vascular cells and various types of PH-diseased lung tissue and determined that ECM stiffening resulted in mechanoactivation of the transcriptional coactivators YAP and TAZ (WWTR1). YAP/TAZ activation modulated metabolic enzymes, including glutaminase (GLS1), to coordinate glutaminolysis and glycolysis. Glutaminolysis, an anaplerotic pathway, replenished aspartate for anabolic biosynthesis, which was critical for sustaining proliferation and migration within stiff ECM. In vitro, GLS1 inhibition blocked aspartate production and reprogrammed cellular proliferation pathways, while application of aspartate restored proliferation. In the monocrotaline rat model of PH, pharmacologic modulation of pulmonary vascular stiffness and YAP-dependent mechanotransduction altered glutaminolysis, pulmonary vascular proliferation, and manifestations of PH. Additionally, pharmacologic targeting of GLS1 in this model ameliorated disease progression. Notably, evaluation of simian immunodeficiency virus-infected nonhuman primates and HIV-infected subjects revealed a correlation between YAP/TAZ-GLS activation and PH. These results indicate that ECM stiffening sustains vascular cell growth and migration through YAP/TAZ-dependent glutaminolysis and anaplerosis, and thereby link mechanical stimuli to dysregulated vascular metabolism. Furthermore, this study identifies potential metabolic drug targets for therapeutic development in PH.
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http://dx.doi.org/10.1172/JCI86387DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5004943PMC
September 2016

Validation and Refinement of Chronic Lung Allograft Dysfunction Phenotypes in Bilateral and Single Lung Recipients.

Ann Am Thorac Soc 2016 05;13(5):627-35

1 Division of Pulmonary and Critical Care Medicine.

Rationale: The clinical course of chronic lung allograft dysfunction (CLAD) is heterogeneous. Forced vital capacity (FVC) loss at onset, which may suggest a restrictive phenotype, was associated with worse survival for bilateral lung transplant recipients in one previously published single-center study.

Objectives: We sought to replicate the significance of FVC loss in an independent, retrospectively identified cohort of bilateral lung transplant recipients and to investigate extended application of this approach to single lung recipients.

Methods: FVC loss and other potential predictors of survival after the onset of CLAD were assessed using Kaplan-Meier and Cox proportional hazards models.

Measurements And Main Results: FVC loss at the onset of CLAD was associated with higher mortality in an independent cohort of bilateral lung transplant recipients (hazard ratio [HR], 2.75; 95% confidence interval [CI], 2.02-3.73; P < 0.0001) and in a multicenter cohort of single lung recipients (HR, 1.80; 95% CI, 1.09-2.98; P = 0.02). Including all subjects, the deleterious impact of FVC loss on survival persisted after adjustment for other relevant clinical variables (HR, 2.36; 95% CI, 1.77-3.15; P < 0.0001). In patients who develop CLAD without FVC loss, chest computed tomography features suggestive of pleural or parenchymal fibrosis also predicted worse survival in both bilateral (HR, 2.01; 95% CI, 1.16-5.20; P = 0.02) and single recipients (HR, 2.47; 95% CI, 1.24-10.57; P = 0.02).

Conclusions: We independently validated the prognostic significance of FVC loss for bilateral lung recipients and demonstrated that this approach to CLAD classification also confers prognostic information for single lung transplant recipients. Improved understanding of these discrete phenotypes is critical to the development of effective therapies.
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http://dx.doi.org/10.1513/AnnalsATS.201510-719OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5018895PMC
May 2016

Proinflammatory high-density lipoprotein results from oxidized lipid mediators in the pathogenesis of both idiopathic and associated types of pulmonary arterial hypertension.

Pulm Circ 2015 Dec;5(4):640-8

Division of Cardiology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.

Pulmonary arterial hypertension (PAH) is characterized by abnormal elaboration of vasoactive peptides, endothelial cell dysfunction, vascular remodeling, and inflammation, which collectively contribute to its pathogenesis. We investigated the potential for high-density lipoprotein (HDL) dysfunction (i.e., proinflammatory effects) and abnormal plasma eicosanoid levels to contribute to the pathobiology of PAH and assessed ex vivo the effect of treatment with apolipoprotein A-I mimetic peptide 4F on the observed HDL dysfunction. We determined the "inflammatory indices" HII and LII for HDL and low-density lipoprotein (LDL), respectively, in subjects with idiopathic PAH (IPAH) and associated PAH (APAH) by an in vitro monocyte chemotaxis assay. The 4F was added ex vivo, and repeat LII and HII values were obtained versus a sham treatment. We further determined eicosanoid levels in plasma and HDL fractions from patients with IPAH and APAH relative to controls. The LIIs were significantly higher for IPAH and APAH patients than for controls. Incubation of plasma with 4F before isolation of LDL and HDL significantly reduced the LII values, compared with sham-treated LDL, for IPAH and APAH. The increased LII values reflected increased states of LDL oxidation and thereby increased proinflammatory effects in both cohorts. The HIIs for both PAH cohorts reflected a "dysfunctional HDL phenotype," that is, proinflammatory HDL effects. In contrast to "normal HDL function," the determined HIIs were significantly increased for the IPAH and APAH cohorts. Ex vivo 4F treatment significantly improved the HDL function versus the sham treatment. Although there was a significant "salutary effect" of 4F treatment, this did not entirely normalize the HII. Significantly increased levels for both IPAH and APAH versus controls were evident for the eicosanoids 9-HODE, 13-HODE, 5-HETE, 12-HETE, and 15-HETE, while no statistical differences were evident for comparisons of IPAH and APAH for the determined plasma eicosanoid levels in the HDL fractions. Our study has further implicated the putative role of "oxidant stress" and inflammation in the pathobiology of PAH. Our data suggest the influences on the "dysfunctional HDL phenotype" of increased oxidized fatty acids, which are paradoxically proinflammatory. We speculate that therapies that target either the "inflammatory milieu" or the "dysfunctional HDL phenotype," such as apoA-I mimetic peptides, may be valuable avenues of further research in pulmonary vascular diseases.
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http://dx.doi.org/10.1086/683695DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4671738PMC
December 2015

Matrix Remodeling Promotes Pulmonary Hypertension through Feedback Mechanoactivation of the YAP/TAZ-miR-130/301 Circuit.

Cell Rep 2015 Nov 22;13(5):1016-32. Epub 2015 Oct 22.

Divisions of Cardiovascular and Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. Electronic address:

Pulmonary hypertension (PH) is a deadly vascular disease with enigmatic molecular origins. We found that vascular extracellular matrix (ECM) remodeling and stiffening are early and pervasive processes that promote PH. In multiple pulmonary vascular cell types, such ECM stiffening induced the microRNA-130/301 family via activation of the co-transcription factors YAP and TAZ. MicroRNA-130/301 controlled a PPAR?-APOE-LRP8 axis, promoting collagen deposition and LOX-dependent remodeling and further upregulating YAP/TAZ via a mechanoactive feedback loop. In turn, ECM remodeling controlled pulmonary vascular cell crosstalk via such mechanotransduction, modulation of secreted vasoactive effectors, and regulation of associated microRNA pathways. In vivo, pharmacologic inhibition of microRNA-130/301, APOE, or LOX activity ameliorated ECM remodeling and PH. Thus, ECM remodeling, as controlled by the YAP/TAZ-miR-130/301 feedback circuit, is an early PH trigger and offers combinatorial therapeutic targets for this devastating disease.
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http://dx.doi.org/10.1016/j.celrep.2015.09.049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4644508PMC
November 2015

CT Scan Segmental Airway Lumen Area.

Chest 2015 Jul;148(1):e33

Western Sussex Hospitals Trust, Chichester, England.

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http://dx.doi.org/10.1378/chest.15-0677DOI Listing
July 2015

Genetic and hypoxic alterations of the microRNA-210-ISCU1/2 axis promote iron-sulfur deficiency and pulmonary hypertension.

EMBO Mol Med 2015 Jun;7(6):695-713

Divisions of Cardiovascular Medicine and Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA

Iron-sulfur (Fe-S) clusters are essential for mitochondrial metabolism, but their regulation in pulmonary hypertension (PH) remains enigmatic. We demonstrate that alterations of the miR-210-ISCU1/2 axis cause Fe-S deficiencies in vivo and promote PH. In pulmonary vascular cells and particularly endothelium, hypoxic induction of miR-210 and repression of the miR-210 targets ISCU1/2 down-regulated Fe-S levels. In mouse and human vascular and endothelial tissue affected by PH, miR-210 was elevated accompanied by decreased ISCU1/2 and Fe-S integrity. In mice, miR-210 repressed ISCU1/2 and promoted PH. Mice deficient in miR-210, via genetic/pharmacologic means or via an endothelial-specific manner, displayed increased ISCU1/2 and were resistant to Fe-S-dependent pathophenotypes and PH. Similar to hypoxia or miR-210 overexpression, ISCU1/2 knockdown also promoted PH. Finally, cardiopulmonary exercise testing of a woman with homozygous ISCU mutations revealed exercise-induced pulmonary vascular dysfunction. Thus, driven by acquired (hypoxia) or genetic causes, the miR-210-ISCU1/2 regulatory axis is a pathogenic lynchpin causing Fe-S deficiency and PH. These findings carry broad translational implications for defining the metabolic origins of PH and potentially other metabolic diseases sharing similar underpinnings.
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http://dx.doi.org/10.15252/emmm.201404511DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4459813PMC
June 2015

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

Am J Respir Crit Care Med 2015 Feb;191(4):455-63

1 Division of Pulmonary and Critical Care Medicine, Department of Medicine, and.

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.
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http://dx.doi.org/10.1164/rccm.201406-1086OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4351593PMC
February 2015

Systems-level regulation of microRNA networks by miR-130/301 promotes pulmonary hypertension.

J Clin Invest 2014 Aug 24;124(8):3514-28. Epub 2014 Jun 24.

Development of the vascular disease pulmonary hypertension (PH) involves disparate molecular pathways that span multiple cell types. MicroRNAs (miRNAs) may coordinately regulate PH progression, but the integrative functions of miRNAs in this process have been challenging to define with conventional approaches. Here, analysis of the molecular network architecture specific to PH predicted that the miR-130/301 family is a master regulator of cellular proliferation in PH via regulation of subordinate miRNA pathways with unexpected connections to one another. In validation of this model, diseased pulmonary vessels and plasma from mammalian models and human PH subjects exhibited upregulation of miR-130/301 expression. Evaluation of pulmonary arterial endothelial cells and smooth muscle cells revealed that miR-130/301 targeted PPARγ with distinct consequences. In endothelial cells, miR-130/301 modulated apelin-miR-424/503-FGF2 signaling, while in smooth muscle cells, miR-130/301 modulated STAT3-miR-204 signaling to promote PH-associated phenotypes. In murine models, induction of miR-130/301 promoted pathogenic PH-associated effects, while miR-130/301 inhibition prevented PH pathogenesis. Together, these results provide insight into the systems-level regulation of miRNA-disease gene networks in PH with broad implications for miRNA-based therapeutics in this disease. Furthermore, these findings provide critical validation for the evolving application of network theory to the discovery of the miRNA-based origins of PH and other diseases.
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http://dx.doi.org/10.1172/JCI74773DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4109523PMC
August 2014

Improved transplant-free survival in patients with systemic sclerosis-associated pulmonary hypertension and interstitial lung disease.

Arthritis Rheumatol 2014 Jul;66(7):1900-8

University of California, Los Angeles.

Objective: Survival in patients with systemic sclerosis (SSc)-associated pulmonary hypertension (PH) and interstitial lung disease (ILD) is poor. Evidence supporting the efficacy of aggressive pulmonary arterial hypertension (PAH)-targeted therapy in this population is limited. The aim of this study was to investigate transplant-free survival in patients with isolated SSc-related PAH or SSc-related PH-ILD who were treated with aggressive PAH-targeted therapy.

Methods: SSc patients with right-sided heart catheterization (RHC)-diagnosed precapillary PH (mean pulmonary artery pressure ≥25 mm Hg, pulmonary capillary wedge pressure ≤15 mm Hg, and pulmonary vascular resistance ≥240 dynes × second/cm(5) ) were included. Patients were classified as having ILD based on review of high-resolution computed tomography (CT) chest imaging and spirometry. The Kaplan-Meier method was applied and Cox proportional hazards models were constructed to analyze survival and identify predictive variables.

Results: Of 99 patients with SSc-related precapillary PH, 28% had SSc-related PAH and 72% had SSc-related PH-ILD. The 1- and 2-year survival estimates were, respectively, 72% and 59% in the SSc-related PH-ILD group versus 82% and 66% in the SSc-related PAH group (P = 0.5). Within 6 months of the diagnostic RHC, 24% of all patients were started on prostanoid therapy; an additional 24% were started on prostanoid therapy after 6 months. In the multivariate model, male sex (hazard ratio [HR] 0.7, P = 0.01) and prostanoid therapy initiation within 6 months of the RHC (HR 1.4, P = 0.01) were the only factors significantly associated with transplant-free survival, after accounting for the presence of ILD and severity of PH.

Conclusion: In this study, survival of patients with SSc-related PH-ILD was modestly improved relative to historical series. While these findings may not be generalizable, improved survival may be due partly to aggressive PAH-targeted therapy.
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http://dx.doi.org/10.1002/art.38623DOI Listing
July 2014

Changes in right heart haemodynamics and echocardiographic function in an advanced phenotype of pulmonary hypertension and right heart dysfunction associated with pulmonary fibrosis.

Thorax 2014 Feb;69(2):123-9

Thoracic Transplantation, Heart-Lung Institute, St Joseph Hospital & Medical Center, , Phoenix, Arizona, USA.

Background: Pulmonary hypertension (PH)-targeted therapy in the setting of pulmonary fibrosis (PF) is controversial; the main clinical concern is worsening of systemic hypoxaemia. We sought to determine the effects of gentle initiation and chronic administration of parenteral treprostinil on right heart function in patients with PF associated with an advanced PH phenotype.

Methods: Open-label, prospective analysis of patients with PF-PH referred for lung transplantation (LT). Advanced PH was defined as mean pulmonary artery pressure (mPAP) ≥35 mm Hg. We compared haemodynamics, Doppler echocardiography (DE), oxygenation, dyspnoea and quality of life indices, and 6 min walk distance (6MWD) before and 12 weeks after parenteral treprostinil.

Results: 15 patients were recruited in the study. After therapy, there were significant improvements in right heart haemodynamics (right atrial pressure (9.5 ± 3.4 vs 6.0 ± 3.7); mPAP (47 ± 8 vs 38.9 ± 13.4); CI (2.3 ± 0.5 vs 2.7 ± 0.6); pulmonary vascular resistance (698 ± 278 vs 496 ± 229); transpulmonary gradient (34.7 ± 8.7 vs 28.5 ± 10.3); mvO2 (65 ± 7.2 vs 70.9 ± 7.4); and stroke volume index (29.2 ± 6.7 vs 33 ± 7.3)) and DE parameters reflecting right heart function (right ventricular (RV) end diastolic area (36.4 ± 5.2 vs 30.9 ± 8.2 cm(2)), left ventricular eccentricity index (1.7 ± 0.6 vs 1.3 ± 0.5), tricuspid annular planar systolic excursion (1.6 ± 0.5 vs 1.9 ± 0.2 cm)). These changes occurred without significant alteration in systemic oxygenation, heart rate, or mean systemic arterial pressure. In addition, improvements were seen in 6MWD (171 ± 93 vs 230 ± 114), 36-Item Short Form Health Survey Mental Component Summary aggregate (38 ± 11 vs 44.2 ± 10.7), University of California, San Diego Shortness of Breath Questionnaire (87 ± 17.1 vs 73.1 ± 21), and brain natriuretic peptide (558 ± 859 vs 228 ± 340).

Conclusions: PH-targeted therapy may improve right heart haemodynamics and echocardiographic function without affecting systemic oxygen saturation in an advanced PH phenotype associated with RV dysfunction in the setting of PF.
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http://dx.doi.org/10.1136/thoraxjnl-2013-204150DOI Listing
February 2014

CXCR3 ligands are associated with the continuum of diffuse alveolar damage to chronic lung allograft dysfunction.

Am J Respir Crit Care Med 2013 Nov;188(9):1117-25

1 Division of Pulmonary and Critical Care Medicine, Department of Medicine.

Rationale: After lung transplantation, insults to the allograft generally result in one of four histopathologic patterns of injury: (1) acute rejection, (2) lymphocytic bronchiolitis, (3) organizing pneumonia, and (4) diffuse alveolar damage (DAD). We hypothesized that DAD, the most severe form of acute lung injury, would lead to the highest risk of chronic lung allograft dysfunction (CLAD) and that a type I immune response would mediate this process.

Objectives: Determine whether DAD is associated with CLAD and explore the potential role of CXCR3/ligand biology.

Methods: Transbronchial biopsies from all lung transplant recipients were reviewed. The association between the four injury patterns and subsequent outcomes were evaluated using proportional hazards models with time-dependent covariates. Bronchoalveolar lavage (BAL) concentrations of the CXCR3 ligands (CXCL9/MIG, CXCL10/IP10, and CXCL11/ITAC) were compared between allograft injury patterns and "healthy" biopsies using linear mixed-effects models. The effect of these chemokine alterations on CLAD risk was assessed using Cox models with serial BAL measurements as time-dependent covariates.

Measurements And Main Results: There were 1,585 biopsies from 441 recipients with 62 episodes of DAD. An episode of DAD was associated with increased risk of CLAD (hazard ratio, 3.0; 95% confidence interval, 1.9-4.7) and death (hazard ratio, 2.3; 95% confidence interval, 1.7-3.0). There were marked elevations in BAL CXCR3 ligand concentrations during DAD. Furthermore, prolonged elevation of these chemokines in serial BAL fluid measurements predicted the development of CLAD.

Conclusions: DAD is associated with marked increases in the risk of CLAD and death after lung transplantation. This association may be mediated in part by an aberrant type I immune response involving CXCR3/ligands.
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http://dx.doi.org/10.1164/rccm.201305-0861OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3863740PMC
November 2013

Interaction between Pseudomonas and CXC chemokines increases risk of bronchiolitis obliterans syndrome and death in lung transplantation.

Am J Respir Crit Care Med 2013 Mar 17;187(5):518-26. Epub 2013 Jan 17.

Division of Infectious Diseases, Department of Medicine, School of Public Health, University of California, Los Angeles, CA 90095, USA.

Rationale: Pseudomonas aeruginosa is the most commonly isolated gram-negative bacterium after lung transplantation and has been shown to up-regulate glutamic acid-leucine-arginine-positive (ELR(+)) CXC chemokines associated with bronchiolitis obliterans syndrome (BOS), but the effect of pseudomonas on BOS and death has not been well defined.

Objectives: To determine if the influence of pseudomonas isolation and ELR(+) CXC chemokines on the subsequent development of BOS and the occurrence of death is time dependent.

Methods: A three-state model was developed to assess the likelihood of transitioning from lung transplant (state 1) to BOS (state 2), from transplant (state 1) to death (state 3), and from BOS (state 2) to death (state 3). This Cox semi-Markovian approach determines state survival rates and cause-specific hazards for movement from one state to another.

Measurements And Main Results: The likelihood of transition from transplant to BOS was increased by acute rejection, CXCL5, and the interaction between pseudomonas and CXCL1. The pseudomonas effect in this transition was due to infection rather than colonization. Movement from transplant to death was facilitated by pseudomonas infection and single lung transplant. Transition from BOS to death was affected by the length of time in state 1 and by the interactions between any pseudomonas isolation and CXCL5 and aspergillus, either independently or in combination.

Conclusions: Our model demonstrates that common post-transplantation events drive movement from one post-transplantation state to another and influence outcomes differently depending upon when after transplantation they occur. Pseudomonas and the ELR(+) CXC chemokines may interact to negatively influence lung transplant outcomes.
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http://dx.doi.org/10.1164/rccm.201207-1228OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3733405PMC
March 2013

Pathologic findings in lung allografts with anti-HLA antibodies.

J Heart Lung Transplant 2013 Mar 10;32(3):326-32. Epub 2013 Jan 10.

Division of Anatomic Pathology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90025, USA.

Background: Despite data indicating a positive correlation between donor-specific anti-HLA antibodies (DSAs) and early development of bronchiolitis obliterans syndrome (BOS) in lung allografts, the role of an antibody-mediated process in acute and chronic lung allograft rejection has not been elucidated. In this study we evaluated pathologic features of transplant lung biopsies in patients with and without DSAs.

Methods: Forty-one lung transplant biopsies from 41 patients at our institution were included in our study. The biopsy H&E slides were reviewed in a blinded fashion, and scored for presence of microvascular inflammation, acute rejection, bronchiolar inflammation and acute lung injury, as well as diffuse alveolar damage (DAD). Microvascular inflammation was graded by the presence of capillary neutrophils on a scale of 0 to 4(+). For immunohistochemical analysis, the pattern and intensity of staining for C4d and C3d deposition were evaluated in airways and alveolar capillaries.

Results: Histopathology suspicious for antibody-mediated rejection (AMR)-defined as≥2(+) neutrophilic infiltration and/or DAD-were more common in DSA-positive cases than controls (11 of 16 vs 6 of 25, p<0.01). Evidence of allograft dysfunction was significantly more common among patients with both DSA and suspicious histopathology compared with controls (5 of 10 vs 3 of 25, p = 0.03). The combination of DSAs and histopathology suspicious for AMR was associated with both BOS (p = 0.002) and mortality (p = 0.03). Immunohistochemistry for C3d and C4d showed no correlation with each other, DSAs or histopathology.

Conclusions: Grade 2(+) neutrophilic infiltration is the histopathologic finding most closely related to DSAs with graft dysfunction and development of BOS in lung transplant recipients and may be a marker for AMR.
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http://dx.doi.org/10.1016/j.healun.2012.11.018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3878303PMC
March 2013