ABSTRACT
Despite growing recognition of the need for increased diversity among students, trainees, and faculty in health care, the medical workforce still lacks adequate representation from groups historically underrepresented in medicine (URiM). The subspecialty field of pediatric pulmonology is no exception. Although there have been efforts to address issues of diversity, equity, and inclusion (DEI) in our own field, gaps persist. To address these gaps, the members of the Diversity, Equity, and Inclusion Advisory Group (DEI-AG) of the American Thoracic Society Pediatrics Assembly created and distributed a Needs Assessment Survey in the United States and Canada to better understand the racial and ethnic demographics of the pediatric pulmonary workforce and to learn more about successes, gaps, and opportunities to enhance how we recruit, train, and retain a diverse workforce. The DEI-AG leadership cochairs convened a workshop to review the findings of the DEI Needs Assessment Survey and to develop strategies to improve the recruitment and retention of URiM fellows and faculty. This Official ATS Workshop Report aims to identify barriers and opportunities for recruitment, training, and career development within the field of pediatric pulmonology. Additionally, we offer useful strategies and resources to improve the recruitment of URiM residents, the mentorship of trainees and junior faculty, and the career development of URiM faculty in academic centers. This Workshop Report is an important first deliverable by the DEI-AG. We hope that this work, originating from within the Pediatrics Assembly, will serve as a model for other Assemblies, disciplines across the ATS, and other fields in Pediatrics.
ABSTRACT
Rationale: To identify barriers and opportunities for Ph.D., basic and translational scientists to be fully integrated into clinical units. Objectives: In 2022, an ad hoc committee of the American Thoracic Society developed a project proposal and workshop to identify opportunities and barriers for scientists who do not practice medicine to develop successful careers and achieve tenure-track faculty positions in clinical departments and divisions within academic medical centers (AMCs) in the United States. Methods: This document focuses on results from a survey of adult and pediatric pulmonary, critical care, and sleep medicine division chiefs as well as a survey of workshop participants, including faculty in departmental and school leadership roles in both basic science and clinical units within U.S. AMCs. Results: We conclude that full integration of non-clinically practicing basic and translational scientists into the clinical units, in addition to their traditional placements in basic science units, best serves the tripartite mission of AMCs to provide care, perform research, and educate the next generation. Evidence suggests clinical units do employ Ph.D. scientists in large numbers, but these faculty are often hired into non-tenure track positions, which do not provide the salary support, start-up funds, research independence, or space often associated with hiring in basic science units within the same institution. These barriers to success of Ph.D. faculty in clinical units are largely financial. Conclusions: Our recommendation is for AMCs to consider and explore some of our proposed strategies to accomplish the goal of integrating basic and translational scientists into clinical units in a meaningful way.
Subject(s)
Academic Medical Centers , Physicians , Adult , United States , Humans , Child , Personnel Selection , Leadership , Faculty, MedicalABSTRACT
Rationale: Primary graft dysfunction (PGD) is a severe form of acute lung injury, leading to increased early morbidity and mortality after lung transplant. Obesity is a major health problem, and recipient obesity is one of the most significant risk factors for developing PGD. Objectives: We hypothesized that T-regulatory cells (Tregs) are able to dampen early ischemia-reperfusion events and thereby decrease the risk of PGD, whereas that action is impaired in obese recipients. Methods: We evaluated Tregs, T cells, and inflammatory markers, plus clinical data, in 79 lung transplant recipients and 41 liver or kidney transplant recipients and studied two groups of mice on a high-fat diet (HFD), which did ("inflammatory" HFD) or did not ("healthy" HFD) develop low-grade inflammation with decreased Treg function. Measurements and Main Results: We identified increased levels of IL-18 as a previously unrecognized mechanism that impairs Tregs' suppressive function in obese individuals. IL-18 decreases levels of FOXP3, the key Treg transcription factor, decreases FOXP3 di- and oligomerization, and increases the ubiquitination and proteasomal degradation of FOXP3. IL-18-treated Tregs or Tregs from obese mice fail to control PGD, whereas IL-18 inhibition ameliorates lung inflammation. The IL-18-driven impairment in Tregs' suppressive function before transplant was associated with an increased risk and severity of PGD in clinical lung transplant recipients. Conclusions: Obesity-related IL-18 induces Treg dysfunction that may contribute to the pathogenesis of PGD. Evaluation of Tregs' suppressive function together with evaluation of IL-18 levels may serve as a screening tool to identify obese individuals with an increased risk of PGD before transplant.
Subject(s)
Acute Lung Injury/etiology , Interleukin-18/metabolism , Lung Transplantation/adverse effects , Obesity/complications , Primary Graft Dysfunction/etiology , Reperfusion Injury/etiology , T-Lymphocytes, Regulatory/metabolism , Acute Lung Injury/physiopathology , Adult , Aged , Aged, 80 and over , Animals , Female , Humans , Male , Mice , Mice, Obese , Middle Aged , Primary Graft Dysfunction/physiopathology , Reperfusion Injury/physiopathologyABSTRACT
Bias is a ubiquitous problem in human functioning. It has plagued medical decision making, making physicians prone to errors of perception and judgment. Racial, gender, ethnic, and religious negative biases infest physicians' perception and cognition, causing errors of judgment and behavior that are damaging. In Part 1 of this series of 2 papers, the authors address the problem of harmful bias, the science of cognition, and what is known about how bias functions in human perception and information processing. They lay the groundwork for an approach to reducing negative bias through awareness, reflection, and bias mitigation, an approach in which negative biases can be transformed-by education, experience, practice, and relationships-into positive biases toward one another. The authors propose wisdom as a conceptual framework for imagining a different way of educating medical students. They discuss fundamental cognitive, affective, and reflective components of wisdom-based education. They also review the skills of awareness, using debiasing strategies, compassion, fostering positive emotion, and reflection that are inherent to a wisdom-based approach to eliminating the negative effects of bias in medical education. In Part 2, the authors answer a key question: How can medical educators do better? They describe the interpersonal, structural, and cultural elements supportive of a wisdom-based learning environment, a culture of respect and inclusion in medical education.
Subject(s)
Bias , Education, Medical/trends , Students, Medical/psychology , Cognition , Education, Medical/methods , Empathy , HumansABSTRACT
In Part 1 of this 2-article series, the authors reviewed the problem of unmitigated bias in medical education and proposed a wisdom-based framework for a different way of educating medical students. In this article, Part 2, the authors answer a key question: How can medical educators do better? Is a bias-free environment possible? The answer to the latter question likely is "no." In fact, having a zero-bias goal in mind may blind educators and students to the implicit biases that affect physicians' decisions and actions. Biases appear to be a part of how the human brain works. This article explores ways to neutralize their destructive effects by: (1) increasing awareness of personal biases; (2) using mitigation strategies to protect against the undesirable effects of those biases; (3) working to change some negative biases, particularly learned biases; and (4) fostering positive biases toward others. The authors describe the concrete actions-interpersonal, structural, and cultural actions-that can be taken to reduce negative bias and its destructive effects.
Subject(s)
Bias , Education, Medical/methods , Forecasting/methods , Attitude of Health Personnel , Education, Medical/trends , Humans , Students, Medical/psychologyABSTRACT
BACKGROUND: Primary graft dysfunction (PGD) is the leading cause of early mortality after lung transplantation. Anti-collagen type-V (col(V)) immunity has been observed in animal models of ischemia-reperfusion injury (IRI) and in PGD. We hypothesized that collagen type-V is an innate danger signal contributing to PGD pathogenesis. METHODS: Anti-col(V) antibody production was detected by flow cytometric assay following cultures of murine CD19+ splenic cells with col.(V). Responding murine B cells were phenotyped using surface markers. RNA-Seq analysis was performed on murine CD19+ cells. Levels of anti-col(V) antibodies were measured in 188 recipients from the Lung Transplant Outcomes Group (LTOG) after transplantation. RESULTS: Col(V) induced rapid production of anti-col(V) antibodies from murine CD19+ B cells. Subtype analysis demonstrated innate B-1 B cells bound col.(V). Col(V) induced a specific transcriptional signature in CD19+ B cells with similarities to, yet distinct from, B cell receptor (BCR) stimulation. Rapid de novo production of anti-col(V) Abs was associated with an increased incidence of clinical PGD after lung transplant. CONCLUSIONS: This study demonstrated that col.(V) is an rapidly recognized by B cells and has specific transcriptional signature. In lung transplants recipients the rapid seroconversion to anti-col(V) Ab is linked to increased risk of grade 3 PGD.
Subject(s)
B-Lymphocyte Subsets/physiology , Collagen Type V/immunology , Graft Rejection/immunology , Lung Transplantation , Adult , Aged , Animals , Antibody Formation , Antigens, CD19/metabolism , Cells, Cultured , Female , Flow Cytometry , Humans , Immunity, Innate , Lymphocyte Activation/genetics , Male , Mice , Mice, Inbred C57BL , Middle Aged , TranscriptomeABSTRACT
Despite standardized postoperative care, some lung transplant patients suffer multiple episodes of acute and chronic rejection while others avoid graft problems for reasons that are poorly understood. Using an established model of C57BL/10 to C57BL/6 minor antigen mismatched single lung transplantation, we now demonstrate that the recipient microbiota contributes to variability in the alloimmune response. Specifically, mice from the Envigo facility in Frederick, Maryland contain nearly double the number of CD4+ Foxp3+ regulatory T cells (Tregs ) than mice from the Jackson facility in Bar Harbor, Maine or the Envigo facility in Indianapolis, Indiana (18 vs 9 vs 7%). Lung graft recipients from the Maryland facility thus do not develop acute or chronic rejection. Treatment with broad-spectrum antibiotics decreases Tregs and increases both acute and chronic graft rejection in otherwise tolerant strains of mice. Constitutive depletion of regulatory T cells, using Foxp3-driven expression of diphtheria toxin receptor, leads to the development of chronic rejection and supports the role of Tregs in both acute and chronic alloimmunity. Taken together, our data demonstrate that the microbiota of certain individuals may contribute to tolerance through Treg -dependent mechanisms and challenges the practice of indiscriminate broad-spectrum antibiotic use in the perioperative period.
Subject(s)
CD4-Positive T-Lymphocytes/immunology , Commerce/standards , Forkhead Transcription Factors/physiology , Graft Rejection/prevention & control , Lung Diseases/immunology , Lung Transplantation/adverse effects , Microbiota , T-Lymphocytes, Regulatory/immunology , Allografts , Animals , CD4-Positive T-Lymphocytes/microbiology , Graft Rejection/etiology , Graft Rejection/metabolism , Graft Survival/immunology , Lung Diseases/microbiology , Lung Diseases/surgery , Male , Mice , Mice, Inbred C57BL , T-Lymphocytes, Regulatory/microbiology , Transplant RecipientsABSTRACT
[This corrects the article DOI: 10.1371/journal.pone.0076451.].
ABSTRACT
Leukocyte-associated Ig-like receptor 1 (LAIR1) is an ITIM-bearing collagen receptor expressed by leukocytes and is implicated in immune suppression. However, using a divalent soluble LAIR1/Fc recombinant protein to block interaction of cell surface LAIR1 with matrix collagen, we found that whereas Th1 responses were enhanced as predicted, Th17 responses were strongly inhibited. Indeed, LAIR1 on both T cells and monocytes was required for optimal Th17 responses to collagen type (Col)V. For pre-existing "natural" Th17 response to ColV, the LAIR1 requirement was absolute, whereas adaptive Th17 and Th1/17 immune responses in both mice and humans were profoundly reduced in the absence of LAIR1. Furthermore, the addition of C1q, a natural LAIR1 ligand, decreased Th1 responses in a dose-dependent manner, but it had no effect on Th17 responses. In IL-17-dependent murine organ transplant models of chronic rejection, LAIR1+/+ but not LAIR1-/- littermates mounted strong fibroproliferative responses. Surface LAIR1 expression was higher on human Th17 cells as compared with Th1 cells, ruling out a receptor deficiency that could account for the differences. We conclude that LAIR1 ligation by its natural ligands favors Th17 cell development, allowing for preferential activity of these cells in collagen-rich environments. The emergence of cryptic self-antigens such as the LAIR1 ligand ColV during ischemia/reperfusion injury and early acute rejection, as well as the tendency of macrophages/monocytes to accumulate in the allograft during chronic rejection, favors Th17 over Th1 development, posing a risk to long-term graft survival.
Subject(s)
Graft Rejection/immunology , Receptors, Immunologic/metabolism , Th1 Cells/physiology , Th17 Cells/immunology , Animals , Autoantigens/immunology , Cells, Cultured , Collagen/metabolism , Humans , Immunity, Cellular , Immunomodulation , Interleukin-17/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Monocytes/immunology , Organ Transplantation , Protein Binding , Receptors, Immunologic/geneticsABSTRACT
RATIONALE: Pulmonary hypertension from pulmonary arterial hypertension or parenchymal lung disease is associated with an increased risk for primary graft dysfunction after lung transplantation. OBJECTIVE: We evaluated the clinical determinants of severe primary graft dysfunction in pulmonary hypertension and developed and validated a prognostic model. METHODS: We conducted a retrospective cohort study of patients in the multicenter Lung Transplant Outcomes Group with pulmonary hypertension at transplant listing. Severe primary graft dysfunction was defined as PaO2/FiO2 ≤200 with allograft infiltrates at 48 or 72 hours after transplantation. Donor, recipient, and operative characteristics were evaluated in a multivariable explanatory model. A prognostic model derived using donor and recipient characteristics was then validated in a separate cohort. RESULTS: In the explanatory model of 826 patients with pulmonary hypertension, donor tobacco smoke exposure, higher recipient body mass index, female sex, listing mean pulmonary artery pressure, right atrial pressure and creatinine at transplant, cardiopulmonary bypass use, transfusion volume, and reperfusion fraction of inspired oxygen were associated with primary graft dysfunction. Donor obesity was associated with a lower risk for primary graft dysfunction. Using a 20% threshold for elevated risk, the prognostic model had good negative predictive value in both derivation and validation cohorts (89.1% [95% confidence interval, 85.3-92.8] and 83.3% [95% confidence interval, 78.5-88.2], respectively), but low positive predictive value. CONCLUSIONS: Several recipient, donor, and operative characteristics were associated with severe primary graft dysfunction in patients with pulmonary hypertension, including several risk factors not identified in the overall transplant population. A prognostic model with donor and recipient clinical risk factors alone had low positive predictive value, but high negative predictive value, to rule out high risk for primary graft dysfunction.
Subject(s)
Hypertension, Pulmonary/complications , Lung Transplantation/adverse effects , Lung/physiopathology , Primary Graft Dysfunction/epidemiology , Adult , Body Mass Index , Female , Humans , Linear Models , Logistic Models , Male , Middle Aged , Obesity/complications , Prognosis , Retrospective Studies , Risk Factors , Time Factors , Tissue Donors , United States , Young AdultABSTRACT
Chronic graft-versus-host disease (cGvHD) remains a major complication of allogeneic stem cell transplantation requiring novel therapies. CD146 and CCR5 are expressed by activated T cells and associated with increased T cell migration capacity and Th17 polarization. We performed a multiparametric flow cytometry analysis in a cohort of 40 HSCT patients together with a cGvHD murine model to understand the role of CD146-expressing subsets. We observed an increased frequency of CD146+ CD4 T cells in the 20 patients with active cGvHD with enhanced RORγt expression. This Th17-prone subset was enriched for cells coexpressing CD146 and CCR5 that harbor mixed Th1/Th17 features and were more frequent in cGvHD patients. Utilizing a murine cGvHD model with bronchiolitis obliterans (BO), we observed that donor T cells from CD146-deficient mice versus those from WT mice caused significantly reduced pulmonary cGvHD. Reduced cGvHD was not the result of failed germinal center B cell or T follicular helper cell generation. Instead, CD146-deficient T cells had significantly lower pulmonary macrophage infiltration and T cell CCR5, IL-17, and IFN-γ coexpression, suggesting defective pulmonary end-organ effector mechanisms. We, thus, evaluated the effect of TMP778, a small-molecule RORγt activity inhibitor. TMP778 markedly alleviated cGvHD in murine models similarly to agents targeting the Th17 pathway, such as STAT3 inhibitor or IL-17-blocking antibody. Our data suggest CD146-expressing T cells as a cGvHD biomarker and suggest that targeting the Th17 pathway may represent a promising therapy for cGvHD.
ABSTRACT
Lung transplantation, a cure for a number of end-stage lung diseases, continues to have the worst long-term outcomes when compared with other solid organ transplants. Preclinical modeling of the most common and serious lung transplantation complications are essential to better understand and mitigate the pathophysiological processes that lead to these complications. Various animal and in vitro models of lung transplant complications now exist and each of these models has unique strengths. However, significant issues, such as the required technical expertise as well as the robustness and clinical usefulness of these models, remain to be overcome or clarified. The National Heart, Lung, and Blood Institute (NHLBI) convened a workshop in March 2016 to review the state of preclinical science addressing the three most important complications of lung transplantation: primary graft dysfunction (PGD), acute rejection (AR), and chronic lung allograft dysfunction (CLAD). In addition, the participants of the workshop were tasked to make consensus recommendations on the best use of these complimentary models to close our knowledge gaps in PGD, AR, and CLAD. Their reviews and recommendations are summarized in this report. Furthermore, the participants outlined opportunities to collaborate and directions to accelerate research using these preclinical models.
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Airway epithelial CD55 down-regulation occurs in several hypoxia-associated pulmonary diseases, but the mechanism is unknown. Using in vivo and in vitro assays of pharmacologic inhibition and gene silencing, the current study investigated the role of hypoxia-inducible factor (HIF)-1α in regulating airway epithelial CD55 expression. Hypoxia down-regulated CD55 expression on small-airway epithelial cells in vitro, and in murine lungs in vivo; the latter was associated with local complement activation. Treatment with pharmacologic inhibition or silencing of HIF-1α during hypoxia-recovered CD55 expression in small-airway epithelial cells. HIF-1α overexpression or blockade, in vitro or in vivo, down-regulated CD55 expression. Collectively, these data show a key role for HIF-1α in regulating the expression of CD55 on airway epithelium.
Subject(s)
CD55 Antigens/metabolism , Epithelium/metabolism , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Lung/metabolism , Amino Acids, Dicarboxylic/pharmacology , Animals , Cell Hypoxia/drug effects , Complement Activation/drug effects , Down-Regulation/drug effects , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Epithelium/drug effects , Gene Silencing/drug effects , Male , Mice, Inbred C57BLABSTRACT
Idiopathic pulmonary fibrosis is a devastating disease, with no good diagnostic biomarker and limited treatment options. Previous studies suggest that collagen V overexpression and collagen V-mediated immune response play roles in the pathogenesis of idiopathic pulmonary fibrosis. This study aimed to identify dysregulated miRNA-related collagen V overexpression during idiopathic pulmonary fibrosis. We found that the expression levels of miR-185 and miR-186 were decreased in the lungs of idiopathic pulmonary fibrosis patients. The levels of miR-185 and miR-186 were not correlated with disease severity of idiopathic pulmonary fibrosis. The direct regulation of COL5A1 by miR-185 and miR-186 was confirmed by a luciferase reporter assay. Furthermore, mimics of miR-185 and miR-186 blocked transforming growth factor-ß-induced collagen V overexpression and alleviated transforming growth factor-ß-induced epithelial-mesenchymal transition in A549 cells and HCC827 cells. Our findings suggest that attenuated expression of miR-185 and miR-186 may be responsible for collagen V overexpression during idiopathic pulmonary fibrosis, and these miRNAs may serve as pathogenesis-related biomarkers and treatment targets.
Subject(s)
Collagen Type V/biosynthesis , Epithelial-Mesenchymal Transition/genetics , Idiopathic Pulmonary Fibrosis/pathology , MicroRNAs/metabolism , Aged , Blotting, Western , Female , Gene Expression Regulation/genetics , Humans , Idiopathic Pulmonary Fibrosis/genetics , Idiopathic Pulmonary Fibrosis/metabolism , Male , Middle Aged , Real-Time Polymerase Chain ReactionABSTRACT
BACKGROUND: Lung transplantation outcomes are among the least favorable, with most recipients eventually developing bronchiolitis obliterans syndrome (BOS) and subsequent graft failure. The presence of human leukocyte antigen (HLA)-DR has been implicated in the pathogenesis of BOS and may play a role in these poor outcomes. METHODS: Lung transplant donor and recipient data were retrospectively gathered from the United Network for Organ Sharing database from January 2006 to June 2013. Donor and recipient characteristics, proportion of recipients treated for first year rejection, and 5-y rates of survival and freedom from BOS were determined according to HLA-DR1, -DR7, -DR13, and -DR15 status in both donor and recipient. Each HLA-DR allele was stratified by donor-recipient pair positivity status. RESULTS: A total of 7402 lung transplant recipients met the inclusion and exclusion criteria. There were significant but small differences in donor and recipient characteristics for each HLA-DR group. The recipients in the D(-)R(+) pairing for HLA-DR13 and those in the D(+)R(-) pairing for HLA-DR15 had significantly higher rates of receiving treatment for rejection within the first year after transplant (P = 0.024 and P = 0.001, respectively). There were no differences in 5-y survival or freedom from BOS for any of the four HLA-DR alleles studied. CONCLUSIONS: There are higher rates of patients treated for rejection within the first year who are either negative for the HLA-DR15 allele but received a donor-positive lung or positive for the HLA-DR13 allele but received a donor-negative lung for that allele. However, these differences do not appear to affect long-term outcomes.
Subject(s)
Bronchiolitis Obliterans/immunology , Graft Rejection/immunology , HLA-DR Serological Subtypes/metabolism , Lung Transplantation , Postoperative Complications/immunology , Adult , Aged , Biomarkers/metabolism , Bronchiolitis Obliterans/etiology , Female , Humans , Logistic Models , Lung Transplantation/mortality , Male , Middle Aged , Outcome Assessment, Health Care , Retrospective Studies , Survival AnalysisABSTRACT
RATIONALE: Committed to its mission of conducting and supporting research that addresses the health needs of all sectors of the nation's population, the Division of Lung Diseases, National Heart, Lung, and Blood Institute of the National Institutes of Health (NHLBI/NIH) seeks to identify issues that impact the training and retention of underrepresented individuals in the biomedical research workforce. OBJECTIVES: Early-stage investigators who received grant support through the NIH Research Supplements to Promote Diversity in Health Related Research Program were invited to a workshop held in Bethesda, Maryland in June, 2015, in order to (1) assess the effectiveness of the current NHLBI diversity program, (2) improve its strategies towards achieving its goal, and (3) provide guidance to assist the transition of diversity supplement recipients to independent NIH grant support. METHODS: Workshop participants participated in five independent focus groups to discuss specific topics affecting underrepresented individuals in the biomedical sciences: (1) Socioeconomic barriers to success for diverse research scientists; (2) role of the academic research community in promoting diversity; (3) life beyond a research project grant: non-primary investigator career paths in research; (4) facilitating career development of diverse independent research scientists through NHLBI diversity programs; and (5) effectiveness of current NHLBI programs for promoting diversity of the biomedical workforce. MEASUREMENTS AND MAIN RESULTS: Several key issues experienced by young, underrepresented biomedical scientists were identified, and solutions were proposed to improve on training and career development for diverse students, from the high school to postdoctoral trainee level, and address limitations of currently available diversity programs. Although some of the challenges mentioned, such as cost of living, limited parental leave, and insecure extramural funding, are also likely faced by nonminority scientists, these issues are magnified among diversity scientists and are complicated by unique circumstances in this group, such as limited exposure to science at a young age, absence of role models and mentors from underrepresented backgrounds, and social norms that relegate their career endeavors, particularly among women, to being subordinate to their expected cultural role. CONCLUSIONS: The factors influencing the participation of underrepresented minorities in the biomedical workforce are complex and span several continuous or overlapping stages in the professional development of scientists from these groups. Therefore, a multipronged approach is needed to enable the professional development and retention of underrepresented minorities in biomedical research. This approach should address both individual and social factors and should involve funding agencies, academic institutions, mentoring teams, professional societies, and peer collaboration. Implementation of some of the recommendations, such as access to child care, institutional support and health benefits for trainees, teaching and entrepreneurial opportunities, grant-writing webinars, and pre-NIH career development (Pre-K) pilot programs would not only benefit biomedical scientists from underrepresented groups but also improve the situation of nondiverse junior scientists. However, other issues, such as opportunities for early exposure to science of disadvantaged/minority groups, and identifying mentors/life coaches/peer mentors who come from similar cultural backgrounds and vantage points, are unique to this group.
Subject(s)
Biomedical Research , Education/economics , Financing, Government , National Heart, Lung, and Blood Institute (U.S.) , Research Personnel/education , Female , Humans , Male , Minority Groups , United States , WorkforceABSTRACT
Complement activation, an integral arm of innate immunity, may be the critical link to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Whereas we have previously reported elevated anaphylatoxins-complement component 3a (C3a) and complement component 5a (C5a)-in IPF, which interact with TGF-ß and augment epithelial injury in vitro, their role in IPF pathogenesis remains unclear. The objective of the current study is to determine the mechanistic role of the binding of C3a/C5a to their respective receptors (C3aR and C5aR) in the progression of lung fibrosis. In normal primary human fetal lung fibroblasts, C3a and C5a induces mesenchymal activation, matrix synthesis, and the expression of their respective receptors. We investigated the role of C3aR and C5aR in lung fibrosis by using bleomycin-injured mice with fibrotic lungs, elevated local C3a and C5a, and overexpression of their receptors via pharmacologic and RNA interference interventions. Histopathologic examination revealed an arrest in disease progression and attenuated lung collagen deposition (Masson's trichrome, hydroxyproline, collagen type I α 1 chain, and collagen type I α 2 chain). Pharmacologic or RNA interference-specific interventions suppressed complement activation (C3a and C5a) and soluble terminal complement complex formation (C5b-9) locally and active TGF-ß1 systemically. C3aR/C5aR antagonists suppressed local mRNA expressions of tgfb2, tgfbr1/2, ltbp1/2, serpine1, tsp1, bmp1/4, pdgfbb, igf1, but restored the proteoglycan, dcn Clinically, compared with pathologically normal human subjects, patients with IPF presented local induction of C5aR, local and systemic induction of soluble C5b-9, and amplified expression of C3aR/C5aR in lesions. The blockade of C3aR and C5aR arrested the progression of fibrosis by attenuating local complement activation and TGF-ß/bone morphologic protein signaling as well as restoring decorin, which suggests a promising therapeutic strategy for patients with IPF.-Gu, H., Fisher, A. J., Mickler, E. A., Duerson, F., III, Cummings, O. W., Peters-Golden, M., Twigg, H. L., III, Woodruff, T. M., Wilkes, D. S., Vittal, R. Contribution of the anaphylatoxin receptors, C3aR and C5aR, to the pathogenesis of pulmonary fibrosis.
Subject(s)
Fibroblasts/metabolism , Pulmonary Fibrosis/metabolism , Receptor, Anaphylatoxin C5a/metabolism , Receptors, Complement/metabolism , Aged , Aged, 80 and over , Animals , Antibiotics, Antineoplastic/toxicity , Bleomycin/toxicity , Cell Line , Collagen Type I, alpha 1 Chain , Complement Membrane Attack Complex/genetics , Complement Membrane Attack Complex/metabolism , Down-Regulation , Gene Expression Regulation/physiology , Humans , Lung Injury/chemically induced , Mice , Mice, Inbred C57BL , Middle Aged , Pulmonary Fibrosis/chemically induced , RNA Interference , Receptor, Anaphylatoxin C5a/genetics , Receptors, Complement/genetics , Signal Transduction/physiology , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/metabolism , Up-RegulationABSTRACT
BACKGROUND: Donor smoking history and higher fraction of inspired oxygen (FIO2) at reperfusion are associated with primary graft dysfunction (PGD) after lung transplantation. We hypothesized that oxidative injury biomarkers would be elevated in PGD, with higher levels associated with donor exposure to cigarette smoke and recipient hyperoxia at reperfusion. METHODS: We performed a nested case-control study of 72 lung transplant recipients from the Lung Transplant Outcomes Group cohort. Using mass spectroscopy, F2-isoprostanes and isofurans were measured in plasma collected after transplantation. Cases were defined in 2 ways: grade 3 PGD present at day 2 or day 3 after reperfusion (severe PGD) or any grade 3 PGD (any PGD). RESULTS: There were 31 severe PGD cases with 41 controls and 35 any PGD cases with 37 controls. Plasma F2-isoprostane levels were higher in severe PGD cases compared with controls (28.6 pg/ml vs 19.8 pg/ml, p = 0.03). Plasma F2-isoprostane levels were higher in severe PGD cases compared with controls (29.6 pg/ml vs 19.0 pg/ml, p = 0.03) among patients reperfused with FIO2 >40%. Among recipients of lungs from donors with smoke exposure, plasma F2-isoprostane (38.2 pg/ml vs 22.5 pg/ml, p = 0.046) and isofuran (66.9 pg/ml vs 34.6 pg/ml, p = 0.046) levels were higher in severe PGD compared with control subjects. CONCLUSIONS: Plasma levels of lipid peroxidation products are higher in patients with severe PGD, in recipients of lungs from donors with smoke exposure, and in recipients exposed to higher Fio2 at reperfusion. Oxidative injury is an important mechanism of PGD and may be magnified by donor exposure to cigarette smoke and hyperoxia at reperfusion.
Subject(s)
Hyperoxia/blood , Lung Transplantation/adverse effects , Postoperative Complications , Primary Graft Dysfunction/blood , Reperfusion Injury/complications , Smoking/adverse effects , Adult , Biomarkers/blood , Female , Follow-Up Studies , Humans , Hyperoxia/etiology , Lipid Peroxidation , Male , Primary Graft Dysfunction/etiology , Reperfusion Injury/blood , Retrospective Studies , Time Factors , Tissue DonorsABSTRACT
We have shown previously that collagen V (col(V)) autoimmunity is a consistent feature of atherosclerosis in human coronary artery disease and in the Apoe(-/-) mouse model. We have also shown sensitization of Apoe(-/-) mice with col(V) to markedly increase the atherosclerotic burden, providing evidence of a causative role for col(V) autoimmunity in atherosclerotic pathogenesis. Here we sought to determine whether induction of immune tolerance to col(V) might ameliorate atherosclerosis, providing further evidence for a causal role for col(V) autoimmunity in atherogenesis and providing insights into the potential for immunomodulatory therapeutic interventions. Mucosal inoculation successfully induced immune tolerance to col(V) with an accompanying reduction in plaque burden in Ldlr(-/-) mice on a high-cholesterol diet. The results therefore demonstrate that inoculation with col(V) can successfully ameliorate the atherosclerotic burden, suggesting novel approaches for therapeutic interventions. Surprisingly, tolerance and reduced atherosclerotic burden were both dependent on the recently described IL-35 and not on IL-10, the immunosuppressive cytokine usually studied in the context of induced tolerance and amelioration of atherosclerotic symptoms. In addition to the above, using recombinant protein fragments, we were able to localize two epitopes of the α1(V) chain involved in col(V) autoimmunity in atherosclerotic Ldlr(-/-) mice, suggesting future courses of experimentation for the characterization of such epitopes.