Idiopathic Pulmonary Fibrosis Is Associated with Common Genetic Variants and Limited Rare Variants

Rationale: Idiopathic pulmonary fibrosis (IPF) is a rare, irreversible, and progressive disease of the lungs. Common genetic variants, in addition to nongenetic factors, have been consistently associated with IPF. Rare variants identified by candidate gene, family-based, and exome studies have also been reported to associate with IPF. However, the extent to which rare variants, genome-wide, may contribute to the risk of IPF remains unknown. Objectives: We used whole-genome sequencing to investigate the role of rare variants, genome-wide, on IPF risk. Methods: As part of the Trans-Omics for Precision Medicine Program, we sequenced 2,180 cases of IPF. Association testing focused on the aggregated effect of rare variants (minor allele frequency ⩽0.01) within genes or regions. We also identified individual rare variants that are influential within genes and estimated the heritability of IPF on the basis of rare and common variants. Measurements and Main Results: Rare variants in both TERT and RTEL1 were significantly associated with IPF. A single rare variant in each of the TERT and RTEL1 genes was found to consistently influence the aggregated test statistics. There was no significant evidence of association with other previously reported rare variants. The SNP heritability of IPF was estimated to be 32% (SE = 3%). Conclusions: Rare variants within the TERT and RTEL1 genes and well-established common variants have the largest contribution to IPF risk overall. Efforts in risk profiling or the development of therapies for IPF that focus on TERT, RTEL1, common variants, and environmental risk factors are likely to have the largest impact on this complex disease.

Incidence and Progression of Fibrotic Lung Disease in an At-Risk Cohort

Rationale: Relatives of patients with familial interstitial pneumonia (FIP) are at increased risk for pulmonary fibrosis and develop preclinical pulmonary fibrosis (PrePF). Objectives: We defined the incidence and progression of new-onset PrePF and its relationship to survival among first-degree relatives of families with FIP. Methods: This is a cohort study of family members with FIP who were initially screened with a health questionnaire and chest high-resolution computed tomography (HRCT) scan, and approximately 4 years later, the evaluation was repeated. A total of 493 asymptomatic first-degree relatives of patients with FIP were evaluated at baseline, and 296 (60%) of the original subjects participated in the subsequent evaluation. Measurements and Main Results: The median interval between HRCTs was 3.9 years (interquartile range, 3.5-4.4 yr). A total of 252 subjects who agreed to repeat evaluation were originally determined not to have PrePF at baseline; 16 developed PrePF. A conservative estimate of the annual incidence of PrePF is 1,023 per 100,000 person-years (95% confidence interval, 511-1,831 per 100,000 person-years). Of 44 subjects with PrePF at baseline, 38.4% subjects had worsening dyspnea compared with 15.4% of those without PrePF (P = 0.002). Usual interstitial pneumonia by HRCT (P < 0.0002) and baseline quantitative fibrosis score (P < 0.001) are also associated with worsening dyspnea. PrePF at the initial screen is associated with decreased survival (P < 0.001). Conclusions: The incidence of PrePF in this at-risk population is at least 100-fold higher than that reported for sporadic idiopathic pulmonary fibrosis (IPF). Although PrePF and IPF represent distinct entities, our study demonstrates that PrePF, like IPF, is progressive and associated with decreased survival.

Treatment Outcomes for Rheumatoid Arthritis-Associated Interstitial Lung Disease: A Real-World, Multisite Study of the Impact of Immunosuppression on Pulmonary Function Trajectory

BACKGROUND

Rheumatoid arthritis (RA)-associated interstitial lung disease (ILD) is common in patients with RA and leads to significant morbidity and mortality. No randomized, placebo-controlled data are available that support the role of immunosuppression to treat RA-associated ILD, despite being widely used in clinical practice.

RESEARCH QUESTION

How does immunosuppression impact pulmonary function trajectory in a multisite retrospective cohort of patients with RA-associated ILD?

STUDY DESIGN AND METHODS

Patients with RA who started treatment for ILD with mycophenolate, azathioprine, or rituximab were identified retrospectively from five ILD centers. Change in lung function before and after treatment was analyzed using a linear spline mixed-effect model with random intercept. Prespecified secondary analyses examined the impact of radiologic pattern of ILD (ie, usual interstitial pneumonia [UIP] vs non-UIP) on treatment trajectory.

RESULTS

Two hundred twelve patients were included in the analysis: 92 patients (43.4%) were treated with azathioprine, 77 patients (36.3%) were treated with mycophenolate mofetil, and 43 patients (20.3%) were treated with rituximab. In the combined analysis of all three agents, an improvement in FVC % predicted was found after 12 months of treatment compared with the potential 12-month response without treatment (+3.90%; P ≤ .001; 95% CI, 1.95-5.84). Diffusing capacity of the lungs for carbon monoxide (Dlco) % predicted also improved at 12 months (+4.53%; P ≤ .001; 95% CI, 2.12-6.94). Neither the UIP pattern of ILD nor choice of immunosuppressive agent significantly impacted the pulmonary function trajectory on immunosuppression.

INTERPRETATION

Immunosuppression was associated with an improved trajectory in FVC and Dlco compared with the pretreatment pulmonary function trajectory. Prospective, randomized trials are required to validate these findings.

Aberrant Multiciliogenesis in Idiopathic Pulmonary Fibrosis

We previously identified a novel molecular subtype of idiopathic pulmonary fibrosis (IPF) defined by increased expression of cilium-associated genes, airway mucin gene MUC5B, and KRT5 marker of basal cell airway progenitors. Here we show the association of MUC5B and cilia gene expression in human IPF airway epithelial cells, providing further rationale for examining the role of cilium genes in the pathogenesis of IPF. We demonstrate increased multiciliogenesis and changes in motile cilia structure of multiciliated cells both in IPF and bleomycin lung fibrosis models. Importantly, conditional deletion of a cilium gene, Ift88 (intraflagellar transport 88), in Krt5 basal cells reduces Krt5 pod formation and lung fibrosis, whereas no changes are observed in Ift88 conditional deletion in club cell progenitors. Our findings indicate that aberrant injury-activated primary ciliogenesis and Hedgehog signaling may play a causative role in Krt5 pod formation, which leads to aberrant multiciliogenesis and lung fibrosis. This implies that modulating cilium gene expression in Krt5 cell progenitors is a potential therapeutic target for IPF.

ALVR109, an off-the-shelf partially HLA matched SARS-CoV-2-specific T cell therapy, to treat refractory severe COVID-19 pneumonia in a heart transplant patient: Case report

An unvaccinated adult male heart transplant recipient patient with recalcitrant COVID-19 due to SARS-CoV-2 delta variant with rising nasopharyngeal quantitative viral load was successfully treated with ALVR109, an off-the-shelf SARS-CoV-2-specific T cell therapy. Background immunosuppression included 0.1 mg/kg prednisone, tacrolimus, and mycophenolate mofetil 1 gm twice daily for historical antibody-mediated rejection. Prior therapies included remdesivir, corticosteroids, and tocilizumab, with requirement for high-flow nasal oxygen. Lack of clinical improvement and acutely rising nasopharyngeal viral RNA more than 3 weeks into illness prompted the request of ALVR109 through an emergency IND. The day following the first ALVR109 infusion, the patient's nasopharyngeal SARS-CoV-2 RNA declined from 7.43 to 5.02 log₁₀ RNA copies/ml. On post-infusion day 4, the patient transitioned to low-flow oxygen. Two subsequent infusions of ALVR109 were administered 10 and 26 days after the first; nasopharyngeal SARS-CoV-2 RNA became undetectable on Day 11, and he was discharged the following day on low-flow oxygen 5 weeks after the initial diagnosis of COVID-19. The clinical and virologic improvements observed in this patient following administration of ALVR109 suggest a potential benefit that warrants further exploration in clinical trials.

Rapidly progressive respiratory failure after helminth larvae ingestion

BACKGROUND

Self-administration of helminths has gained attention among patients as a potential but unproven therapy for autoimmune disease. We present a case of rapidly progressive respiratory failure in a patient with systemic sclerosis (SSc) and pulmonary arterial hypertension (PAH) as a result of self-administration of parasitic organisms.

CASE

A 45-year-old woman with a history of interstitial lung disease and PAH due to limited cutaneous SSc presented to pulmonary clinic with worsening dyspnea, cough, and new onset hypoxemia. Three months prior to presentation she started oral helminth therapy with Necator americanus as an alternative treatment for SSc. Laboratory evaluation revelaed eosinophilia and elevated IgE levels. IgG antibodies to Strongyloides were detected. High resolution computed tomography of the chest revealed progressive ILD and new diffuse ground glass opacities. Transthoracic echocardiogram and right heart catheterization illustrated worsening PAH and right heart failure. The patient was admitted to the hospital and emergently evaluated for lung transplantation but was not a candidate for transplantation due to comorbidities. Despite aggressive treatment for PAH and right heart failure, her respiratory status deteriorated, and the patient transitioned to comfort-focused care.

CONCLUSION

Although ingestion of helminths poses a risk of infection, helminth therapy has been investigated as a potential treatment for autoimmune diseases. In this case, self-prescribed helminth ingestion precipitated fatal acute worsening of lung inflammation, hypoxemia, and right heart dysfunction, highlighting the risk of experimental helminth therapy in patients, especially those with underlying respiratory disease.

Acute myocardial infarction secondary to mucormycosis after lung transplantation

We present a case of a 57-year-old man who underwent bilateral lung transplantation for idiopathic pulmonary fibrosis. His immediately post-operative course was complicated by fever and cardiac arrest. Despite supportive care and broad-spectrum antibiotics, he experienced continued clinical decline. Autopsy results indicated angioinvasive mucormycosis and coronary arteritis resulting in acute myocardial infarction as the cause of death.

Alcohol Use Disorders Are Associated With a Unique Impact on Airway Epithelial Cell Gene Expression

BACKGROUND

Alcohol use disorders (AUDs) and cigarette smoking both increase risk for the development of community-acquired pneumonia (CAP), likely through adverse effects on proximal airway mucociliary clearance and pathogen recognition. Smoking-related alterations on airway gene expression are well described, but little is known about the impact of AUDs. We measured gene expression in human airway epithelial cells (AECs), hypothesizing that AUDs would be associated with novel differences in gene expression that could alter risk for CAP.

METHODS

Bronchoscopy with airway brushings was performed in participants with AUDs and controls to obtain AECs. An AUD Identification Test was used to define AUD. RNA was extracted from AECs, and mRNA expression data were collected on an Agilent micro-array. Differential expression analyses were performed on the filtered and normalized data with correction for multiple testing. Enrichment analyses were performed using clusterProfiler.

RESULTS

Expression data from 19 control and 18 AUD participants were evaluated. After adjustment for smoking, AUDs were associated with significant differential expression of 520 AEC genes, including genes for ribosomal proteins and genes involved in protein folding. Enrichment analyses indicated significant differential expression of 24 pathways in AUDs, including those implicated in protein targeting to membrane and viral gene expression. Smoking-associated AEC gene expression differences mirrored previous reports, but differed from those associated with AUDs.

CONCLUSIONS

AUDs have a distinct impact on AEC gene expression that may influence proximal airway function independent of smoking. Alcohol-associated alterations may influence risk for CAP through modifying key mechanisms important in protecting proximal airway integrity.

MUC5B variant is associated with visually and quantitatively detected preclinical pulmonary fibrosis

BACKGROUND

Relatives of patients with familial interstitial pneumonia (FIP) are at increased risk for pulmonary fibrosis. We assessed the prevalence and risk factors for preclinical pulmonary fibrosis (PrePF) in first-degree relatives of patients with FIP and determined the utility of deep learning in detecting PrePF on CT.

METHODS

First-degree relatives of patients with FIP over 40 years of age who believed themselves to be unaffected by pulmonary fibrosis underwent CT scans of the chest. Images were visually reviewed, and a deep learning algorithm was used to quantify lung fibrosis. Genotyping for common idiopathic pulmonary fibrosis risk variants in MUC5B and TERT was performed.

FINDINGS

In 494 relatives of patients with FIP from 263 families of patients with FIP, the prevalence of PrePF on visual CT evaluation was 15.6% (95% CI 12.6 to 19.0). Compared with visual CT evaluation, deep learning quantitative CT analysis had 84% sensitivity (95% CI 0.72 to 0.89) and 86% sensitivity (95% CI 0.83 to 0.89) for discriminating subjects with visual PrePF diagnosis. Subjects with PrePF were older (65.9, SD 10.1 years) than subjects without fibrosis (55.8 SD 8.7 years), more likely to be male (49% vs 37%), more likely to have smoked (44% vs 27%) and more likely to have the MUC5B promoter variant rs35705950 (minor allele frequency 0.29 vs 0.21). MUC5B variant carriers had higher quantitative CT fibrosis scores (mean difference of 0.36%), a difference that remains significant when controlling for age and sex.

INTERPRETATION

PrePF is common in relatives of patients with FIP. Its prevalence increases with age and the presence of a common MUC5B promoter variant. Quantitative CT analysis can detect these imaging abnormalities.

Resequencing Study Confirms That Host Defense and Cell Senescence Gene Variants Contribute to the Risk of Idiopathic Pulmonary Fibrosis

Rationale: Several common and rare genetic variants have been associated with idiopathic pulmonary fibrosis, a progressive fibrotic condition that is localized to the lung. Objectives: To develop an integrated understanding of the rare and common variants located in multiple loci that have been reported to contribute to the risk of disease. Methods: We performed deep targeted resequencing (3.69 Mb of DNA) in cases (n = 3,624) and control subjects (n = 4,442) across genes and regions previously associated with disease. We tested for associations between disease and 1) individual common variants via logistic regression and 2) groups of rare variants via sequence kernel association tests. Measurements and Main Results: Statistically significant common variant association signals occurred in all 10 of the regions chosen based on genome-wide association studies. The strongest risk variant is the MUC5B promoter variant rs35705950, with an odds ratio of 5.45 (95% confidence interval, 4.91-6.06) for one copy of the risk allele and 18.68 (95% confidence interval, 13.34-26.17) for two copies of the risk allele (P = 9.60 × 10-295). In addition to identifying for the first time that rare variation in FAM13A is associated with disease, we confirmed the role of rare variation in the TERT and RTEL1 gene regions in the risk of IPF, and found that the FAM13A and TERT regions have independent common and rare variant signals. Conclusions: A limited number of common and rare variants contribute to the risk of idiopathic pulmonary fibrosis in each of the resequencing regions, and these genetic variants focus on biological mechanisms of host defense and cell senescence.

Translational research in pulmonary fibrosis

Pulmonary fibrosis refers to the development of diffuse parenchymal abnormalities in the lung that cause dyspnea, cough, hypoxemia, and impair gas exchange, ultimately leading to respiratory failure. Though pulmonary fibrosis can be caused by a variety of underlying etiologies, ranging from genetic defects to autoimmune diseases to environmental exposures, once fibrosis develops it is irreversible and most often progressive, such that fibrosis of the lung is one of the leading indications for lung transplantation. This review aims to provide a concise summary of the recent advances in our understanding of the genetics and genomics of pulmonary fibrosis, idiopathic pulmonary fibrosis in particular, and how these recent discoveries may be changing the clinical approach to diagnosing and treating patients with fibrotic interstitial lung disease.

The relationship between complement C3 expression and the MUC5B genotype in pulmonary fibrosis

The common gain-of-function MUC5B promoter variant ( rs35705950 ) is the strongest risk factor for the development of idiopathic pulmonary fibrosis (IPF). While the role of complement in IPF is controversial, both MUC5B and the complement system play a role in lung host defense. The aim of this study was to evaluate the relationship between complement component 3 (C3) and MUC5B in patients with IPF and in bleomycin-induced lung injury in mice. To do this, we evaluated C3 gene expression in whole lung tissue from 300 subjects with IPF and 175 healthy controls. Expression of C3 was higher in IPF than healthy controls {1.40-fold increase [95% confidence interval (CI) 1.31-1.50]; P < 0.0001} and even greater among IPF subjects with the highest-risk IPF MUC5B promoter genotype [TT vs. GG = 1.59-fold (95% CI 1.15-2.20); P < 0.05; TT vs. GT = 1.66-fold (95% CI 1.20-2.30); P < 0.05]. Among subjects with IPF, C3 expression was significantly higher in the lung tissue without microscopic honeycombing than in the lung tissue with microscopic honeycombing [1.40-fold increase (95% CI 1.23- 1.59); P < 0.01]. In mice, while bleomycin exposure increased Muc5b protein expression, C3-deficient mice were protected from bleomycin-induced lung injury. In aggregate, our findings indicate that the MUC5B promoter variant is associated with higher C3 expression and suggest that the complement system may contribute to the pathogenesis of IPF.

Radiographic Review of Current Therapeutic and Monitoring Devices in the Chest

Chest radiographs are obtained as a standard part of clinical care. Rapid advancements in medical technology have resulted in a myriad of new medical devices, and familiarity with their imaging appearance is a critical yet increasingly difficult endeavor. Many modern thoracic medical devices are new renditions of old designs and are often smaller than older versions. In addition, multiple device designs serving the same purpose may have varying morphologies and positions within the chest. The radiologist must be able to recognize and correctly identify the proper positioning of state-of-the-art medical devices and identify any potential complications that could impact patient care and management. To familiarize radiologists with the arsenal of newer thoracic medical devices, this review describes the indications, radiologic appearance, complications, and magnetic resonance imaging safety of each device. ^©RSNA, 2018.

Genetics in Idiopathic Pulmonary Fibrosis Pathogenesis, Prognosis, and Treatment

Idiopathic pulmonary fibrosis (IPF), the most common form of idiopathic interstitial pneumonia (IIP), is characterized by irreversible scarring of the lung parenchyma and progressive decline in lung function leading to eventual respiratory failure. The prognosis of IPF is poor with a median survival of 3–5 years after diagnosis and no curative medical therapies. Although the pathogenesis of IPF is not well understood, there is a growing body of evidence that genetic factors contribute to disease risk. Recent studies have identified common and rare genetic variants associated with both sporadic and familial forms of pulmonary fibrosis, with at least one-third of the risk for developing fibrotic IIP explained by common genetic variants. The IPF-associated genetic loci discovered to date are implicated in diverse biological processes, including alveolar stability, host defense, cell–cell barrier function, and cell senescence. In addition, some common variants have also been associated with distinct clinical phenotypes. Better understanding of how genetic variation plays a role in disease risk and phenotype could identify potential therapeutic targets and inform clinical decision-making. In addition, clinical studies should be designed controlling for the genetic backgrounds of subjects, since clinical outcomes and therapeutic responses may differ by genotype. Further understanding of these differences will allow the development of personalized approaches to the IPF management.

Pulmonary fibrosis in the era of stratified medicine

Both common and rare variants contribute to the genetic architecture of pulmonary fibrosis. Genome-wide association studies have identified common variants, or those with a minor allele frequency of >5%, that are linked to pulmonary fibrosis. The most widely replicated variant (rs35705950) is located in the promoter region of the MUC5B gene and has been strongly associated with idiopathic pulmonary fibrosis (IPF) and familial interstitial pneumonia (FIP) across multiple different cohorts. However, many more common variants have been identified with disease risk and in aggregate account for approximately one-third of the risk of IPF. Moreover, several of these common variants appear to have prognostic potential. Next generation sequencing technologies have facilitated the identification of rare variants. Recent whole exome sequencing studies have linked pathogenic rare variants in multiple new genes to FIP. Compared with common variants, rare variants have lower population allele frequencies and higher effect sizes. Pulmonary fibrosis rare variants genes can be subdivided into two pathways: telomere maintenance and surfactant metabolism. Heterozygous rare variants in telomere-related genes co-segregate with adult-onset pulmonary fibrosis with incomplete penetrance, lead to reduced protein function, and are associated with short telomere lengths. Despite poor genotype-phenotype correlations, lung fibrosis associated with pathogenic rare variants in different telomere genes is progressive and displays similar survival characteristics. In contrast, many of the heterozygous rare variants in the surfactant genes predict a gain of toxic function from protein misfolding and increased endoplasmic reticulum (ER) stress. Evidence of both telomere shortening and increased ER stress have been found in sporadic IPF patients, suggesting that the mechanisms identified from rare variant genetic studies in unique individuals and families are applicable to a wider spectrum of patients. The ability to sequence large cohorts of individuals rapidly has the potential to further our understanding of the relative contributions of common and rare variants in the pathogenesis of pulmonary fibrosis. The UK 100,000 Genomes Project will provide opportunities to interrogate both common and rare variants and to investigate how these biological signals provide diagnostic and prognostic information in the era of stratified medicine.

Desmoplakin Variants Are Associated with Idiopathic Pulmonary Fibrosis

RATIONALE

Sequence variation, methylation differences, and transcriptional changes in desmoplakin (DSP) have been observed in patients with idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

To identify novel variants in DSP associated with IPF and to characterize the relationship of these IPF sequence variants with DSP gene expression in human lung.

METHODS

A chromosome 6 locus (7,370,061-7,606,946) was sequenced in 230 subjects with IPF and 228 control subjects. Validation genotyping of disease-associated variants was conducted in 936 subjects with IPF and 936 control subjects. DSP gene expression was measured in lung tissue from 334 subjects with IPF and 201 control subjects.

MEASUREMENTS AND MAIN RESULTS

We identified 23 sequence variants in the chromosome 6 locus associated with IPF. Genotyping of selected variants in our validation cohort revealed that noncoding intron 1 variant rs2744371 (odds ratio = 0.77, 95% confidence interval [CI] = 0.66-0.91, P = 0.002) is protective for IPF, and a previously described IPF-associated intron 5 variant (rs2076295) is associated with increased risk of IPF (odds ratio = 1.36, 95% CI = 1.19-1.56, P < 0.001) after controlling for sex and age. DSP expression is 2.3-fold increased (95% CI = 1.91-2.71) in IPF lung tissue (P < 0.0001). Only the minor allele at rs2076295 is associated with decreased DSP expression (P = 0.001). Staining of fibrotic and normal human lung tissue localized DSP to airway epithelia.

CONCLUSIONS

Sequence variants in DSP are associated with IPF, and rs2076295 genotype is associated with differential expression of DSP in the lung. DSP expression is increased in IPF lung and concentrated in the airway epithelia, suggesting a potential role for DSP in the pathogenesis of IPF.

Incorporating genetics into the identification and treatment of Idiopathic Pulmonary Fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis, the most common form of idiopathic interstitial pneumonia, is characterized by progressive, irreversible scarring of the lung parenchyma. Idiopathic pulmonary fibrosis has a poor prognosis, and there are no medical therapies available that have been shown to improve survival. It is usually sporadic, but there is evidence of familial clustering of pulmonary fibrosis, suggesting a genetic basis for this disease. More recently, studies have confirmed that specific genetic variants are associated with both familial and sporadic forms of pulmonary fibrosis.

DISCUSSION

Although there are common and rare genetic variants that have been associated with the risk of developing pulmonary fibrosis, the genotyping of patients is not a generally accepted strategy. Better understanding of the interplay between genetic risk and environmental exposure is likely needed to inform both treatment and disease prevention. Several identified disease-associated genetic variants have implications for disease progression and survival, but systematic studies of known genetic variants and their influence on therapeutic efficacy are lacking. Future investigations should focus on understanding phenotypic differences between patients carrying different risk alleles, and clinical studies should be designed to control for the influence of different genetic risk variants on patient outcomes. Inherited genetic factors play a significant role in the risk of developing pulmonary fibrosis. Future studies will be needed to characterize patient phenotypes and to understand how these genetic factors will influence clinical decision-making for both diagnosis and treatment of idiopathic pulmonary fibrosis.

Genetic susceptibility and pulmonary fibrosis

PURPOSE OF REVIEW

Recent genetic findings have identified new targets of investigation in the field of pulmonary fibrosis and have the potential to change clinical care.

RECENT FINDINGS

These findings implicate alterations in host defense, cell-to-cell adhesion, and aging and senescence in the pathophysiology of pulmonary fibrosis. At least one common genetic variant strongly associated with pulmonary fibrosis appears to have prognostic implications for patients.

SUMMARY

The inherited risk for pulmonary fibrosis is substantial, and recent data suggest that genetic risk for familial and sporadic forms of the disease are similar. Further characterizing this genetic risk will influence clinical practice in terms of categorization, diagnosis, and screening of individuals for this disease.

How we implemented a resident-led medical simulation curriculum in a large internal medicine residency program

Mannequin-based simulation in graduate medical education has gained widespread acceptance. Its use in non-procedural training within internal medicine (IM) remains scant, possibly due to the logistical barriers to implementation of simulation curricula in large residency programs. We report the Massachusetts General Hospital Department of Medicine's scale-up of a voluntary pilot program to a mandatory longitudinal simulation curriculum in a large IM residency program (n = 54). We utilized an eight-case curriculum implemented over the first four months of the academic year. An intensive care unit curriculum was piloted in the spring. In order to administer a comprehensive curriculum in a large residency program where faculty resources are limited, thirty second-year and third-year residents served as session facilitators and two senior residents served as chairpersons of the program. Post-session anonymous survey revealed high learner satisfaction scores for the mandatory program, similar to those of the voluntary pilot program. Most interns believed the sessions should continue to be mandatory. Utilizing residents as volunteer facilitators and program leaders allowed the implementation of a well-received mandatory simulation program in a large IM residency program and facilitated program sustainability.

Docosatetraenoyl LPA is elevated in exhaled breath condensate in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease with no effective medical therapies. Recent research has focused on identifying the biological processes essential to the development and progression of fibrosis, and on the mediators driving these processes. Lysophosphatidic acid (LPA), a biologically active lysophospholipid, is one such mediator. LPA has been found to be elevated in bronchoalveolar lavage (BAL) fluid of IPF patients, and through interaction with its cell surface receptors, it has been shown to drive multiple biological processes implicated in the development of IPF. Accordingly, the first clinical trial of an LPA receptor antagonist in IPF has recently been initiated. In addition to being a therapeutic target, LPA also has potential to be a biomarker for IPF. There is increasing interest in exhaled breath condensate (EBC) analysis as a non-invasive method for biomarker detection in lung diseases, but to what extent LPA is present in EBC is not known.

METHODS

In this study, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to assess for the presence of LPA in the EBC and plasma from 11 IPF subjects and 11 controls.

RESULTS

A total of 9 different LPA species were detectable in EBC. Of these, docosatetraenoyl (22:4) LPA was significantly elevated in the EBC of IPF subjects when compared to controls (9.18 pM vs. 0.34 pM; p = 0.001). A total of 13 different LPA species were detectable in the plasma, but in contrast to the EBC, there were no statistically significant differences in plasma LPA species between IPF subjects and controls.

CONCLUSIONS

These results demonstrate that multiple LPA species are detectable in EBC, and that 22:4 LPA levels are elevated in the EBC of IPF patients. Further research is needed to determine the significance of this elevation of 22:4 LPA in IPF EBC, as well as its potential to serve as a biomarker for disease severity and/or progression.

Pilot program using medical simulation in clinical decision-making training for internal medicine interns

BACKGROUND

The use of high-fidelity medical simulation in cognitive skills training within internal medicine residency programs remains largely unexplored.

OBJECTIVE

To design a pilot study to introduce clinical decision-making training using simulation into a large internal medicine residency program, explore the practicability of using junior and senior residents as facilitators, and examine the feasibility of using the program to improve interns' clinical skills.

METHODS

Interns on outpatient rotations participated in a simulation curriculum on a voluntary basis. The curriculum consisted of 8 cases focusing on acute clinical scenarios encountered on the wards. One-hour sessions were offered twice monthly from August 2010 to February 2011. Internal medicine residents and simulation faculty served as facilitators.

RESULTS

A total of 36 of 75 total interns volunteered to participate in the program, with 42% attending multiple sessions. Of all participants, 88% rated the sessions as "excellent," 97% felt that the program improved their ability to function as an intern and generate a plan, and 81% reported improvement in differential diagnosis skills.

CONCLUSIONS

Simulation training was well received by the learners and improved self-reported clinical skills. Using residents as facilitators, supervised by faculty, was well received by the learners and enabled the implementation of the curriculum in a large training program. Simulation can provide opportunities for deliberate practice, and learners perceive this modality to be effective.

Role of semaphorin 7a signaling in transforming growth factor β1-induced lung fibrosis and scleroderma-related interstitial lung disease

OBJECTIVE

Semaphorin 7a regulates transforming growth factor β1 (TGFβ1)-induced fibrosis. This study was undertaken to test the hypothesis that semaphorin 7a exerts its profibrotic effects in part by promoting the tissue accumulation of CD45+ fibrocytes.

METHODS

A murine model of pulmonary fibrosis in which an inducible, bioactive form of the human TGFβ1 gene is overexpressed in the lung was used. Fibrosis and fibrocytes were evaluated in TGFβ1-transgenic mice in which the semaphorin 7a locus had been disrupted. The effect of replacement or deletion of semaphorin 7a on bone marrow-derived cells was ascertained using bone marrow transplantation. The role of the semaphorin 7a receptor β1 integrin was assessed using neutralizing antibodies. The applicability of these findings to TGFβ1-driven fibrosis in humans was examined in patients with scleroderma-related interstitial lung disease (ILD).

RESULTS

The appearance of fibrocytes in the lungs of TGFβ1-transgenic mice required semaphorin 7a. Replacement of semaphorin 7a on bone marrow-derived cells restored lung fibrosis and fibrocytes. Immunoneutralization of β1 integrin reduced pulmonary fibrocytes and fibrosis. Peripheral blood mononuclear cells (PBMCs) from patients with scleroderma-related ILD showed increased levels of messenger RNA for semaphorin 7a and its receptors, with semaphorin 7a located on collagen-producing fibrocytes and CD19+ lymphocytes. Peripheral blood fibrocyte outgrowth was enhanced in these patients. Stimulation of normal human PBMCs with recombinant semaphorin 7a enhanced fibrocyte differentiation; these effects were attenuated by β1 integrin neutralization.

CONCLUSION

Our findings indicate that interventions that reduce semaphorin 7a expression or prevent the semaphorin 7a-β1 integrin interaction may ameliorate TGFβ1-driven or fibrocyte-associated autoimmune fibroses.

Local apoptosis promotes collagen production by monocyte-derived cells in transforming growth factor β1-induced lung fibrosis

BACKGROUND

Collagen-containing leukocytes (CD45+Col-I+) accumulate in diseased and fibrotic tissues. However, the precise identity of these cells and whether injury is required for their recruitment remain unknown. Using a murine model of pulmonary fibrosis in which an inducible, bioactive form of the human transforming growth factor (TGF)-β1 gene is targeted to the lung, we characterized the cell surface phenotype of collagen-containing CD45+ cells in the lung and tested the hypothesis that apoptotic cell death responses are essential to the accumulation of CD45+Col-I+ cells.

RESULTS

Our studies demonstrate that CD45+Col-I+ cells appearing in the TGF-β1-exposed murine lung express markers of the monocyte lineage. Inhibition of apoptosis via pharmacological caspase blockade led to a significant reduction in CD45+Col-I+ cells, which appear to accumulate independently of alternatively activated macrophages. There are also increased levels of apoptosis and greater numbers of CD45+Col-I+ in the lung tissue of patients with two distinct forms of fibrotic lung disease, idiopathic pulmonary fibrosis and connective tissue disease-related interstitial lung disease, when compared to lung from healthy normal controls. These findings are accompanied by an increase in collagen production in cultured monocytes obtained from subjects with fibrotic lung disease. Treatment of these cultured cells with the caspase inhibitor carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]-fluoromethylketone (Z-VAD/fmk) reduces both apoptosis and collagen production in all subjects.

CONCLUSIONS

Interventions that prevent collagen production by monocytes via modulation of caspase activation and of apoptosis may be ameliorative in monocyte-associated, TGF-β1-driven processes such as pulmonary fibrosis.