Publications by authors named "Samuel Weigt"

Background: Basiliximab induction immunosuppression is increasingly employed in lung transplant recipients despite limited prospective evidence to support its use in this population. We sought to determine the relationship between basiliximab induction and development of acute rejection, chronic lung allograft dysfunction, and other clinically relevant outcomes in a multicenter lung transplant cohort with variable induction practice patterns.

Methods: We applied propensity-based statistical methods to rigorous, prospectively collected longitudinal data from 768 newly transplanted adult lung recipients at 5 North American centers (368 who received basiliximab induction immunosuppression and 400 who received no induction immunosuppression).

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Small extracellular vesicles (sEVs) isolated from plasma of lung transplant recipients (LTRs) with chronic lung allograft dysfunction (CLAD) contain increased levels of lung associated self-antigens, Kα1 tubulin and collagen V, and decreased expression of the tumor suppressor liver kinase B1 (LKB1). In this study, sEVs were isolated from plasma collected from LTRs with or without cystic fibrosis (CF) from multiple centers at the onset of CLAD and 6 and 12 months before clinical diagnosis of CLAD (n = 32) as well as from time-matched stable controls (n = 25). sEVs were analyzed for Kα1 tubulin, collagen V, and LKB1 by western blot.

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Introduction: We assessed the prognostic utility of circulating levels of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in patients with idiopathic pulmonary fibrosis (IPF) in the IPF-PRO Registry.

Methods: MMP and TIMP concentrations were quantified by ELISA in plasma from 300 patients. A Cox proportional hazard regression model was used to assess associations between select MMPs and TIMPs and death and disease progression (absolute decline in forced vital capacity ≥10% predicted, death, or lung transplant).

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We present a patient with a history of lung transplantation who subsequently underwent dual heart-kidney transplantation for nonischemic cardiomyopathy and chronic kidney disease, becoming one of the rare cases of triple-organ transplantation. This case underscores the evolving challenges and successes in managing complex transplant recipients.

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Article Synopsis
  • Lung transplantation can save lives for patients with serious lung diseases, but complications like primary graft dysfunction (PGD) limit outcomes.
  • A study analyzing samples from the first day after transplant found that certain immune indicators (NKG2D ligands) were linked to severe PGD and poorer recovery metrics.
  • The research suggests that targeting the immune response, specifically NKG2D receptors, could help manage PGD and improve patient outcomes.
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Type 2 alveolar epithelial cells (AEC2s) function as progenitor cells in the lung. We have shown previously that failure of AEC2 regeneration results in progressive lung fibrosis in mice and is a cardinal feature of idiopathic pulmonary fibrosis (IPF). In this study, we identified deficiency of a specific zinc transporter, SLC39A8 (ZIP8), in AEC2s from both IPF lungs and lungs of old mice.

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Importance: Sarcoidosis is an inflammatory granulomatous disease of unknown cause that affects an estimated 2 to 160 people per 100 000 worldwide and can involve virtually any organ. Approximately 10% to 30% of patients with sarcoidosis develop progressive pulmonary disease.

Observation: Among patients with pulmonary sarcoidosis, the rate of spontaneous remission without serious sequelae ranges from 10% to 82%.

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Background: Chronic lung allograft dysfunction (CLAD) phenotype determines prognosis and may have therapeutic implications. Despite the clarity achieved by recent consensus statement definitions, their reliance on radiologic interpretation introduces subjectivity. The Center for Computer Vision and Imaging Biomarkers at the University of California, Los Angeles (UCLA) has established protocols for chest high-resolution computed tomography (HRCT)-based computer-aided quantification of both interstitial disease and air-trapping.

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Pulmonary mesenchymal cells are critical players in both the mouse and human during lung development and disease states. They are increasingly recognized as highly heterogeneous, but there is no consensus on subpopulations or discriminative markers for each subtype. We completed scRNA-seq analysis of mesenchymal cells from the embryonic, postnatal, adult and aged fibrotic lungs of mice and humans.

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The primary factor that limits long-term survival after lung transplantation is chronic lung allograft dysfunction (CLAD). CLAD also impairs quality of life and increases the costs of medical care. Our understanding of CLAD continues to evolve.

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The association of autoimmune disease (AI) with transplant-free survival in the setting of Group 3 pulmonary hypertension and pulmonary fibrosis remains unclear. We report cases of severe pulmonary hypertension (mean pulmonary artery pressure ≥35 mmHg right ventricular dysfunction) and extensive pulmonary fibrosis after pulmonary arterial hypertension-specific therapy. We used multivariate regression to determine the clinical variables associated with transplant-free survival.

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Unlabelled: 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.

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Bronchoalveolar lavage (BAL) is a key clinical and research tool in lung transplantation (LTx). However, BAL collection and processing are not standardized across LTx centers. This International Society for Heart and Lung Transplantation-supported consensus document on BAL standardization aims to clarify definitions and propose common approaches to improve clinical and research practice standards.

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Background: Gastroesophageal reflux disease (GERD) is a risk factor for chronic lung allograft dysfunction. Bile acids-putative markers of gastric microaspiration-and inflammatory proteins in the bronchoalveolar lavage (BAL) have been associated with chronic lung allograft dysfunction, but their relationship with GERD remains unclear. Although GERD is thought to drive chronic microaspiration, the selection of patients for anti-reflux surgery lacks precision.

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Long-term survival after lung transplant lags behind that of other commonly transplanted organs, reflecting the current incomplete understanding of the mechanisms involved in the development of posttransplant lung injury, rejection, infection, and chronic allograft dysfunction. To address this unmet need, 2 ongoing National Institute of Allergy and Infectious Disease funded studies through the Clinical Trials in Organ Transplant Consortium (CTOT) CTOT-20 and CTOT-22 were dedicated to understanding the clinical factors and biological mechanisms that drive chronic lung allograft dysfunction and those that maintain cytomegalovirus polyfunctional protective immunity. The CTOT-20 and CTOT-22 studies enrolled 800 lung transplant recipients at 5 North American centers over 3 years.

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Background: Some interstitial lung disease (ILD) patients develop a progressive fibrosing-ILD phenotype (PF-ILD), with similar persistent lung function decline suggesting common molecular pathways involved. Nintedanib, a tyrosine kinase inhibitor targeting the PDGF, FGF, VEGF and M-CSF pathways, has shown comparable efficacy in idiopathic pulmonary fibrosis (IPF) and systemic sclerosis-associated ILD (SSc-ILD). We hypothesize that Nintedanib targeted molecular pathways will be augmented to a similar degree across PF-ILD regardless of aetiology.

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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.

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Background: Lung transplantation outcomes remain complicated by bronchiolitis obliterans syndrome (BOS), a major cause of mortality and retransplantation for patients. A variety of factors linking inflammation and BOS have emerged, meriting further exploration of the microbiome as a source of inflammation. In this analysis, we determined features of the pulmonary microbiome associated with BOS susceptibility.

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Lung transplantation is an increasingly utilized modality for treating advanced lung disease. However, lung transplant recipients (LTRs) experience high rates of infection-related mortality and, compared with other solid organ transplant recipients, are at increased risk of infectious complications given the intensity of immunosuppression employed, the presence of airway abnormalities after surgery and exposure of the allograft to the environment. Fungal infections, particularly mold infections, are problematic after transplantation as they are often associated with limited treatment options and poor outcomes.

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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.

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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).

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