Long COVID syndrome and the lung: how long will it last?

The prevalence and duration of the long-term respiratory complications of COVID-19 infection remains to be elucidated. This short commentary reports on recently published studies in patients post-acute COVID-19 infection in terms of symptom prevalence, physiological and radiological sequela and where only symptoms are present despite investigation. Pulmonary function testing, 6-min walk tests, computed tomography chest and more advanced imaging modalities have been incorporated to reveal the underlying pathophysiology that cause such disabling symptoms in patient with post-acute COVID-9 syndrome (PACS). PACS has a serious impact on people's ability to return to work, affecting the physical, mental, social sphere and with significant healthcare and general economic consequences for them, their families and society.

Lung organoids and other preclinical models of pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive fatal disease affecting over 100 000 people in Europe with an increasing incidence. Available treatments offer only slowing of disease progression and are poorly tolerated by patients leading to cessation of therapy. Lung transplant remains the only cure. Therefore, alternative treatments are urgently required. The pathology of IPF is complex and poorly understood and thus creates a major obstacle to the discovery of novel treatments. Additionally, preclinical assessment of new treatments currently relies upon animal models where disparities with human lung biology often hamper drug development. At a cellular level, IPF is characterized by persistent and abnormal deposition of extracellular matrix by fibroblasts and alveolar epithelial cell injury which is seen as a key event in initiation of disease progression. In-depth investigation of the role of alveolar epithelial cells in health and disease has been impeded due to difficulties in primary cell isolation and culture ex vivo. Novel strategies employing patient-derived induced pluripotent stem cells engineered to produce type 2 alveolar epithelial cells (iAEC2) cultured as three-dimensional organoids have the potential to overcome these hurdles and inform new effective precision treatments for IPF leading to improved survival and quality of life for patients worldwide.

Exploring the barriers and facilitators for the use of digital health technologies for the management of COPD: a qualitative study of clinician perceptions

BACKGROUND

Digital health technology (DHT) promises to support patients and healthcare professionals (HCPs) to optimize the management of chronic obstructive pulmonary disease (COPD). However, there is a lack of evidence demonstrating the effectiveness of DHT for the management of COPD. One reason for this is the lack of user-involvement in the development of DHT interventions in COPD meaning their needs and preferences are rarely accounted for in the design phase. Although HCP adoption issues have been identified in relation to DHT, little is known about the challenges perceived by HCPs providing care to COPD patients. Therefore, this study aims to qualitatively explore the barriers and facilitators HCPs perceive for the use of DHT in the management of COPD.

METHODS

Participants (n = 32) were recruited using snowball sampling from two university hospitals and several general practitioner clinics. A semi-structured interview was conducted with each participant. NVivo 12 software was used to complete thematic analysis on the data.

RESULTS

Themes identified include: data quality; evidence-based care; resource constraints; and digital literacy presented as barriers; and facilitators include the following themes: digital health training and education; improving HCP digital literacy; and Personalized prescribing. Patient-centered approaches, such as pulmonary rehabilitation and shared decision-making were suggested as implementation strategies to ease the adoption of digital health for the management of COPD.

CONCLUSION

These findings contribute new insights about the needs and preferences of HCPs working in COPD regarding DHT. The findings can be used to help mitigate user-experience issues by informing the design of person-centered implementation and adoption strategies for future digital health interventions in COPD.

Toll-like receptor 3 L412F polymorphism promotes a persistent clinical phenotype in pulmonary sarcoidosis

BACKGROUND/INTRODUCTION

Sarcoidosis is a multi-systemic disorder of unknown etiology, characterized by the presence of non-caseating granulomas in target organs. In 90% of cases, there is thoracic involvement. Fifty to seventy percent of pulmonary sarcoidosis patients will experience acute, self-limiting disease. For the subgroup of patients who develop persistent disease, no targeted therapy is currently available.

AIM

To investigate the potential of the single nucleotide polymorphism (SNP), Toll-like receptor 3 Leu412Phe (TLR3 L412F; rs3775291), as a causative factor in the development of and in disease persistence in pulmonary sarcoidosis. To investigate the functionality of TLR3 L412F in vitro in primary human lung fibroblasts from pulmonary sarcoidosis patients.

DESIGN

SNP-genotyping and cellular assays, respectively, were used to investigate the role of TLR3 L412F in the development of persistent pulmonary sarcoidosis.

METHODS

Cohorts of Irish sarcoidosis patients (n = 228), healthy Irish controls (n = 263) and a secondary cohort of American sarcoidosis patients (n = 123) were genotyped for TLR3 L412F. Additionally, the effect of TLR3 L412F in primary lung fibroblasts from pulmonary sarcoidosis patients was quantitated following TLR3 activation in the context of cytokine and type I interferon production, TLR3 expression and apoptotic- and fibroproliferative-responses.

RESULTS

We report a significant association between TLR3 L412F and persistent clinical disease in two cohorts of Irish and American Caucasians with pulmonary sarcoidosis. Furthermore, activation of TLR3 in primary lung fibroblasts from 412 F-homozygous pulmonary sarcoidosis patients resulted in reduced IFN-β and TLR3 expression, reduced apoptosis- and dysregulated fibroproliferative-responses compared with TLR3 wild-type patients.

DISCUSSION/CONCLUSION

This study identifies defective TLR3 function as a previously unidentified factor in persistent clinical disease in pulmonary sarcoidosis and reveals TLR3 L412F as a candidate biomarker.

The lady with the dragon tattoo

BACKGROUND

Though the skin is affected in sarcoidosis in about one-third of cases, granulomatous tattoo reactions are an unusual manifestation of the disease. It is important phenomenon to recognize, as it frequently leads to the diagnosis of systemic sarcoidosis.

CASE PRESENTATION

A 35-year-old Caucasian female with multiple tattoos presented with a 5-week history of tenderness of the black dye in a tattoo depicting a dragon. She also described a 15-month history of fatigue, polyarthralgia, and mild dyspnea. Skin biopsy demonstrated multiple dermal non-caseating granulomata with associated tattoo ink. Further investigation revealed the presence of systemic sarcoidosis. Her symptoms and skin changes improved with conservative management.

CONCLUSION

Sarcoidal tattoo reactions in those without systemic sarcoidosis are a rare occurrence, and their presence should prompt a search for systemic involvement. The accurate identification of skin involvement in sarcoidosis is important, as it tends to occur early in the course of disease, and the skin is a readily accessible site for biopsy, allowing for prompt diagnosis.

Sarcoidosis, alveolar β-actin and pulmonary fibrosis

BACKGROUND

Sarcoidosis is a multisystem granulomatous disease of unknown aetiology. Proteins present within the alveolar space early in sarcoidosis disease may provide an insight into novel mechanisms for the development of fibrotic disease and in particular pulmonary fibrosis.

METHODS

A modified two-dimensional difference gel electrophoresis protocol was applied to the human bronchoalveolar lavage fluid (hBALF) of four patients with non-persistent pulmonary interstitial disease at 4-year follow-up (defined as mild disease) and four patients who developed pulmonary interstitial disease at 4-year follow-up (defined as severe disease). The protein β-actin was identified by LC-MS/MS from a preparative gel and found to be significantly elevated in early lavages from the severe disease group. To look at the potential pro-fibrotic effects of this protein, primary human pulmonary fibroblasts (CCD-19Lu) were treated with recombinant β-actin following which qPCR and ELISA assays were used to measure any effects.

RESULTS

We found that β-actin levels were significantly elevated in early hBALF samples in patients who subsequently developed severe disease when compared to the mild group. Treating primary human pulmonary fibroblasts with recombinant β-actin led to enhanced gene expression of the pro-fibrotic markers alpha smooth muscle actin and collagen 1 as well as the increased secretion of interleukin-13 and metalloproteinases 3 and 9.

CONCLUSION

Free β-actin within the lungs of sarcoidosis patients potentially may contribute to disease pathogenesis particularly in the context of abnormal remodelling and the development of pulmonary fibrosis.

What is Connected Health and why will it change your practice?

As a society we have to re-imagine our health and social care models to meet the challenge of an ageing population with greater levels of chronic disease. The digital revolution offers us the potential to leverage technological innovations to develop proactive 'connected' health and social care models that are built around the patient's needs to facilitate efficient management of wellness and health throughout their lifespan. However, efforts to utilize technological innovations for this purpose have not been universally successful to date, indicating that technology itself is only part of the solution. To achieve a truly connected, technology enabled, health and social care model we need to overcome some key challenges; first, we need to optimize the process of sensing data from end users in the home and community such that monitoring protocols are built around the person and designed with respect to their needs to provide for accurate and reliable harvesting of target data. We then need to gather and mine large datasets from the home and community to analyse the complex relationships between home and community acquired data and health status. Only then can we begin to design, implement and evaluate new models of care that leverage technology platforms. In meeting this challenge we can leverage technology to transform the way in which we promote and manage wellness and health throughout the lifespan.

Inflammation and cancer: macrophage migration inhibitory factor (MIF)--the potential missing link

Macrophage migration inhibitory factor (MIF) was the original cytokine, described almost 50 years ago and has since been revealed to be an important player in pro-inflammatory diseases. Recent work using MIF mouse models has revealed new roles for MIF. In this review, we present an increasing body of evidence implicating the key pro-inflammatory cytokine MIF in specific biological activities related directly to cancer growth or contributing towards a microenvironment favouring cancer progression.

Prevalence of genetic haemochromatosis and iron overload in patients attending rheumatology and joint replacement clinics

BACKGROUND & AIMS

Genetic Haemochromatosis (GH) is common in North European and Celtic populations and is associated with arthropathy. We aimed to measure the frequency of the common GH mutations (C282Y and H63D), the carrier frequency of C282Y and markers of iron overload in patients who were referred to our rheumatology and joint replacement clinics.

METHODS

Unselected patients attending these clinics were anonymously tested for the described mutations. Transferrin saturation and serum ferritin were also measured and if elevated, the patients had predictive counselling then named GH mutation testing. The carrier and mutation frequencies were also determined in 340 local controls.

RESULTS

One hundred and sixty-one unselected patients attending these clinics were studied. The C282Y mutation carrier frequency was 1 in 5.2 in patients compared with 1 in 8.1 in controls (p < 0.005). The overall mutation frequencies were similar in patients and controls. One patient was found to be a homozygous for the C282Y mutation and eight were compound heterozygotes. Seven other patients had a raised ferritin, one of whom was a C282Y heterozygote.

CONCLUSION

The C282Y carrier frequency is significantly higher in patients attending rheumatology and joint replacement clinics than in controls. Screening of these patients for GH should be considered.

Honeycomb cysts in idiopathic pulmonary haemosiderosis: high-resolution CT appearances in two adults

Idiopathic pulmonary haemosiderosis (IPH) is characterized by recurrent episodes of pulmonary haemorrhage. The disease predominates in childhood, with approximately 20% of patients presenting in adulthood. Most patients present with dyspnoea, fatigue and recurrent haemoptysis, resulting in iron deficiency anaemia. High-resolution CT manifestations of IPH include patchy or diffuse ground glass opacity and consolidation resulting from alveolar haemorrhage. We describe a new high-resolution CT finding in two adults with IPH - multiple honeycomb cysts, which were characteristically focal and localized predominantly to the posterior and lateral basal segments. We suggest that the development of honeycombing in patients with IPH is a traction phenomenon resulting from recurrent haemosiderin deposition in the interstitium, which is known to lead to progressive fibrosis. These honeycomb cysts may indicate the sites of the most severe and recurrent alveolar haemorrhage in adults with IPH.

Genetic variants of microsomal epoxide hydrolase and glutamate-cysteine ligase in COPD

The genetic factors that contribute to the development of chronic obstructive pulmonary disease (COPD) are poorly understood. Many candidate genes have been proposed, including enzymes that protect the lung against oxidative stress, such as microsomal epoxide hydrolase (EPHX1) and glutamate-cysteine ligase (GCL). To date, most reported findings have been for EPHX1, particularly in relation to functional variants associated with fast and slow metabolism of epoxide intermediates. The present study aimed to identify any association of variation in these genes with COPD susceptibility or severity. In total, 1,017 white COPD patients and 912 nondiseased age and sex matched smoking controls were genotyped for six single nucleotide polymorphisms (SNPs) in EPHX1 (including the fast and slow variants and associated haplotypes), and eight SNPs in the two genes encoding GCL. GCL is a rate-limiting enzyme in the synthesis of glutathione, a major contributor to anti-oxidant protection in the lung. No association of variation was found in EPHX1 or GCL with susceptibility to COPD or disease severity. This is the largest reported study to date and is well powered to detect associations that have been previously suggested. The current data indicate that these genetic variants are unlikely to be related to susceptibility or disease severity in white chronic obstructive pulmonary disease patients.

Sarcoidosis and MIF gene polymorphism: a case-control study in an Irish population

Macrophage migration inhibitory factor is a key pro-inflammatory mediator. A 5-CATT repeat functional polymorphism within the promoter of the gene was previously associated with the lowest promoter activity. It was hypothesised that patients exhibiting a 5-CATT allele would have a less aggressive inflammatory response with an associated less severe clinical phenotype in sarcoidosis. Irish Caucasian sarcoidosis patients (n = 173) followed up for 1-39 yrs and a control group (n = 166) were genotyped for the CATT repeat polymorphism. Disease severity at the time of diagnosis and at the time of elaboration of the present study was assessed by the presence of thoracic and extrathoracic symptoms, erythema nodosum, radiographic interstitial changes (chest radiograph score equal to stage II or greater, or high-resolution computed tomography confirmed), pulmonary function tests, steroid use, erythrocyte sedimentation rate, C-reactive protein and angiotensin-converting enzyme levels. In the Irish population studied, no evidence was found of a significant association between either sarcoidosis susceptibility and disease severity and the 5-CATT repeat functional polymorphism in the macrophage migration inhibitory gene. The present study found no significant association between the 5-CATT repeat macrophage migration inhibitory factor gene polymorphism and sarcoidosis, and did not support the overriding role for macrophage migration inhibitory factor in driving sarcoidosis pathogenesis.

Role for macrophage migration inhibitory factor in asthma

Macrophage migration inhibitory factor (MIF) is an immunologic regulator that is expressed in inflammatory and autoimmune disorders. We investigated MIF's role in asthma using genetic approaches in a mouse model and in a cohort of asthma patients. Mice genetically deficient in MIF that were primed and aerosol-challenged with ovalbumin showed less pulmonary inflammation and lower airway hyperresponsiveness than genetically matched, wild-type controls. MIF deficiency also resulted in lower titers of specific IgE, IgG(1), and IgG(2a), and decreased pulmonary, T(H)2 cytokine levels. IL-5 concentrations were lower and corresponded to decreased eosinophil numbers in bronchoalveolar lavage fluid. T cell studies also showed a lower level of antigen-specific responses in MIF-KO versus wild-type mice. In an analysis of 151 white patients with mild, moderate, or severe asthma (Global Initiative for Asthma criteria), a significant association was found between mild asthma and the low-expression, 5-CATT MIF allele. Pharmacologic inhibition of MIF may be beneficial and could be guided by the MIF genotype of affected individuals.

Objective assessment of criteria for selection of donor lungs suitable for transplantation

BACKGROUND

Donor organ shortage severely limits lung transplantation as a therapeutic option, yet many potential donor lungs are deemed unsuitable by clinical selection criteria.

METHODS

Of 39 consecutive potential donor lungs, 14 were accepted and 25 excluded by clinical selection criteria. All were evaluated prospectively by clinical assessment, bronchoscopy, and bronchoalveolar lavage (BAL) to evaluate objectively the discrimination of pulmonary infection and injury.

RESULTS

Accepted donors were significantly younger than those excluded (mean (SD) age 36.7 (15.3) years v 49.5 (13.2) years; p = 0.009, unpaired t test) and were more likely to have suffered traumatic brain death (50% v 20%; p = 0.07, Fisher's exact test). Oxygenation (PaO(2):FiO(2)) was higher in accepted donors than in excluded donors (median (range) 63.2 (48-82.5) kPa v 43.1 (7.7-71.7) kPa; p = 0.0001, Mann-Whitney test). Positive formal BAL culture was more frequent in accepted donors (75%) than in those excluded (43%; p = 0.1, Fisher's exact test). There was no significant difference in the percentage and concentration of neutrophils in BAL fluid between accepted and excluded donors (median (range) 37.9 (0-96.9)% and 44.6 (0-1190)x10(3)/ml v 36 (1-98.1)% and 46 (0.2-1457)x10(3)/ml), nor in the BAL fluid concentration of tumour necrosis factor-alpha (140 (0-340) pg/ml v 160 (0-760) pg/ml) or interleukin 8 (810 (33-17 600) pg/ml v 540 (0-15 110) pg/ml).

CONCLUSION

Current selection criteria are poor discriminators of pulmonary injury and infection and lead to the exclusion of potentially usable donor lungs.

Managing exacerbations of COPD: room for improvement

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are a major cause of hospital admissions. Because of the consequent morbidity, mortality and burden on hospital resources, COPD management guidelines have been formulated. We reviewed 62 consecutive patients with AECOPD admitted from September 1st to December 18th 2000 in St. Vincents University Hospital, Ireland, including 3 months follow-up data, to evaluate the quality of care and in particular to assess the care of such patients by respiratory and non-respiratory physicians. There was a frequent failure to objectively confirm the diagnosis of COPD by spirometry (completed in 39 of the 51 patients who, at admission, had been previously labelled with COPD (76%), and in 53 out of 62 patients (85%) at the end of the study period), or to estimate severity by quantifying the FEV1 as a percentage of the normal predicted range (estimated in only 21 of the 39 patients who had spirometry previously performed (53%)). Those patients managed with input from respiratory physicians were more likely to have their diagnosis of COPD confirmed with spirometry (p < 0.05). They were also more likely to have out-patient follow-up arranged at discharge (p < 0.05). There was a trend towards the more frequent prescribing of oxygen to hypoxic patients in "respiratory" than in "non-respiratory" managed cases (p = 0.182) and a shorter hospital stay (0.1 < p < 0.5). 4 out of 11 severely hypoxaemic patients at admission (PO2 < 7.3kPa) were not screened at discharge for possible long term oxygen therapy (36%). 20 patients received combination antibiotic therapy with no infiltrate on CXR (32%). Pulmonary rehabilitation was offered to 12 patients (19%). 5 out of 18 current smokers had documented smoking cessation advice (28%) and none received smoking cessation pharmacotherapy. Finally we noted that the Hospital In-Patient Enquiry (HIPE) data and casualty department admission books were frequently misleading or medical records unlocatable (in 30 out of 92 cases (33%)). We conclude that the management of AECOPD at St. Vincent's University Hospital is frequently suboptimal, and may be managed better with respiratory physician involvement. In particular, there could be more frequent spirometric confirmation of the diagnosis of COPD, better screening for long term oxygen therapy and more conservative use of antibiotics. Audit is complicated by difficulty accessing relevant data.

Macrophage migration inhibitory factor: a neuroendocrine modulator of chronic inflammation

The diverse actions of macrophage migration inhibitory factor (MIF) within the immuno-neuroendocrine system are yet to be fully understood, but it is clear that MIF plays a pivotal role in the regulation of both the innate and adaptive immune response. An emerging body of data presently indicates that MIF's position within the cytokine cascade is to act in concert with glucocorticoids to control the 'set point' and magnitude of the immune and inflammatory response. In this article we will review the actions of MIF within the immune system and discuss the overlapping and contrasting aspects of MIF and glucocorticoid biology. In particular we will focus on the role of MIF within the immuno-neuroendocrine interface and suggest molecular mechanisms by which MIF may counter-regulate glucocorticoid function. Finally we will discuss emerging evidence that functional MIF gene-promoter polymorphisms render one susceptible to elevated MIF expression, and the development of an exaggerated immune/inflammatory response that potentiates the progression to chronic inflammatory disease.

Pulmonary cystic hydatid disease in Ireland

BACKGROUND

Hydatid disease is rare in Ireland and its incidence and prevalence are unknown. Most cases are diagnosed by a combination of clinical findings, morphological features on imaging and by serological testing.

AIMS

We describe an Irish case of pulmonary hydatid disease detected at bronchoscopy by bronchoalveolar lavage, and discuss the diagnosis and treatment of the disorder.

CONCLUSION

The diagnosis of this rare disease requires a high index of suspicion. Treatment is primarily surgical, with a role for antihelminthic agents.

A functional promoter polymorphism in the macrophage migration inhibitory factor (MIF) gene associated with disease severity in rheumatoid arthritis

The macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine and regulates the anti-inflammator effects of glucocorticoids. An important role for MIF within the cytokine cascade is to act in concert with endogenous glucocorticoids to control the set-point and magnitude of the inflammatory response. Elevated expression of MIF in the circulation and in the synovial joint has been documented in rheumatoid arthritis. MIF also has been linked to the development of joint damage and disease pathology in experimental animal models. We describe herein a novel CATT-tetranucleotide repeat polymorphism at position -794 of the human Mif gene and show that it functionally affects the activity of the MIF promoter in gene reporter assays. We describe four genotypes which comprise 5, 6, 7, or 8-CATT repeat units and show that the 5-CATT allele has the lowest level of basal and stimulated MIF promoter activity in vitro. The presence of the low expressing, 5-CATT repeat allele correlated with low disease severity in a cohort of rheumatoid arthritis patients.

The regulation of interleukin-8 by hypoxia in human macrophages--a potential role in the pathogenesis of the acute respiratory distress syndrome (ARDS)

BACKGROUND

The acute respiratory distress syndrome (ARDS) represents a form of severe acute inflammatory lung disease. We have previously demonstrated significantly raised interleukin-8 (IL-8) levels in the lungs of at-risk patients that progress to ARDS, and identified the alveolar macrophage as an important source of this chemokine. We wished to extend this study in a well-defined group of patients with major trauma, and to investigate potential mechanisms for rapid intrapulmonary IL-8 generation.

MATERIALS AND METHODS

Patients with major trauma underwent bronchoalveolar lavage (BAL) and IL-8 levels were measured in BAL fluid by ELISA. Human macrophages were derived from peripheral blood monocytes from healthy volunteers. Rabbit alveolar macrophages were obtained from ex-vivo lavage of healthy rabbit lungs. Macrophages were culture under normoxic or hypoxic (PO2 26 mmHg) conditions. IL-8 and other proinflammatory mediator expression was measured by ELISA, northern blotting or multi-probe RNase protection assay.

RESULTS

In patients with major trauma, IL-8 levels were significantly higher in patients that progressed to ARDS compared to those that did not (n = 56, P = 0.0001). High IL-8 levels negatively correlated with PaO2/FiO2 (r = -0.56, P < 0.001). In human monocyte derived macrophages hypoxia rapidly upregulated IL-8 protein (within 2 hours) and mRNA expression (within 30 mins). Acute hypoxia also increased rabbit alveolar macrophage IL-8 expression. Hypoxia increased DNA binding activity of AP-1 and C/EBP but not NF-kappaB. Hypoxia induced HIF-1 expression, but cobaltous ions and desferrioxamine did not mimic hypoxic IL-8 induction. Hypoxia downregulated a range of other proinflammatory mediators, including MCP-1 and TNF-alpha. Both the pattern of cytokine expression and transcription factor activation by hypoxia was different to that seen with endotoxin.

CONCLUSIONS

Rapidly raised intrapulmonary IL-8 levels are associated with ARDS progression in patients with major trauma. Acute hypoxia, a clinically relevant stimulus, rapidly and selectively upregulates IL-8 in macrophages associated with a novel pattern of transcription factor activation. Acute hypoxia may represent one of potentially several proinflammatory stimuli responsible for rapid intrapulmonary IL-8 generation in patients at-risk of ARDS.

Peripheral blood fibrocytes: differentiation pathway and migration to wound sites

Fibrocytes are a distinct population of blood-borne cells that display a unique cell surface phenotype (collagen I+/CD11b+/CD13+/CD34+/CD45RO+/MHC class II+/CD86+) and exhibit potent immunostimulatory activities. Circulating fibrocytes rapidly enter sites of tissue injury, suggesting an important role for these cells in wound repair. However, the regulatory processes that govern the differentiation of blood-borne fibrocytes and the mechanisms that underlie the migration of these cells to wound sites are currently not known. We report herein that ex vivo cultured fibrocytes can differentiate from a CD14+-enriched mononuclear cell population and that this process requires contact with T cells. Furthermore, we demonstrate that TGF-beta1 (1-10 ng/ml), an important fibrogenic and growth-regulating cytokine involved in wound healing, increases the differentiation and functional activity of cultured fibrocytes. Because fibrocytes home to sites of tissue injury, we examined the role of chemokine/chemokine receptor interactions in fibrocyte trafficking. We show that secondary lymphoid chemokine, a ligand of the CCR7 chemokine receptor, acts as a potent stimulus for fibrocyte chemotaxis in vitro and for the homing of injected fibrocytes to sites of cutaneous tissue injury in vivo. Finally, we demonstrate that differentiated, cultured fibrocytes express alpha smooth muscle actin and contract collagen gels in vitro, two characteristic features of wound-healing myofibroblasts. These data provide important insight into the control of fibrocyte differentiation and trafficking during tissue repair and significantly expand their potential role during wound healing.

Elevated levels of interleukin-8 in donor lungs is associated with early graft failure after lung transplantation

Increased levels of the neutrophil chemokine interleukin (IL)-8 in the lungs of severe trauma patients can predict subsequent development of acute respiratory distress syndrome. Because the lungs of brain-dead organ donors can contain high levels of IL-8, we hypothesized that this may predispose to early graft failure in the recipient after lung transplantation. Twenty-six organ donors prospectively satisfying clinical criteria for lung donation underwent bronchoalveolar lavage and lung biopsy to determine the effect of neutrophil infiltration and IL-8 expression in the donor lung on graft function and survival in 26 respective recipients after lung transplantation. Nine recipients developed severe graft dysfunction, of whom six subsequently died (median survival: 24 d [range: 5 to 39 d]); all others survived beyond 6 mo. The IL-8 signal in the donor lung correlated with the percent neutrophils in bronchoalveolar lavage fluid (BALF) before implantation (42.4 +/- 7.24 [mean +/- SE]%, p = 0.03) and with the degree of impairment in graft oxygenation after implantation (p = 0.01). An increased level of IL-8 in the donor BALF was associated with the development of severe early graft dysfunction (p = 0.027) and with early recipient mortality (p = 0.0034). Use of donor lungs with high IL-8 levels is associated with a poor prognosis after lung transplantation. Attenuating the donor's inflammatory response before organ retrieval may improve early outcome after lung transplantation, and help maximize lung use from the existing donor pool.

Pulmonary endothelial permeability and circulating neutrophil-endothelial markers in patients undergoing esophagogastrectomy

OBJECTIVE

Esophagogastrectomy is an established surgical treatment for esophageal malignancy. The postoperative period may be complicated by the development of acute lung injury syndromes and thus, may provide a useful model in which to study the early pathogenic mechanisms of inflammatory lung injury.

DESIGN

Open, prospective study.

SETTING

High dependency and intensive therapy units.

PATIENTS

Eight healthy male volunteers and 20 patients in the early postoperative period

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The lung protein accumulation index (PAI) of radiolabeled transferrin was determined by using a portable, double-isotope system. The following circulating inflammatory markers-thought to reflect neutrophil-endothelial activation and injury including circulating neutrophil elastase-soluble L-, E-, and P-selectins and thrombomodulin and von Willebrand factor antigen were assayed from venous blood samples The PAI for healthy volunteers was median -0.5 (range, -1.73 to 0.27) x 10(-3)/min and for patients undergoing esophagogastrectomy -0.005 (range, -1.53 to 2.28) x 10(-3)/min. There was no statistical difference between the two groups. In the postesophagogastrectomy group, a significant elevation in circulating levels of neutrophil elastase, soluble P- and E-selectin, thrombomodulin, and von Willebrand factor antigen were observed relative to the control group but only circulating plasma elastase demonstrated a significant correlation with the PAI (r2 = .23, p =.03).

CONCLUSIONS

The data suggest patients undergoing esophagogastrectomy develop a inflammatory response but this is not a surrogate of permeability and other factors are likely to determine persistent injury to the alveolar-capillary barrier function in this patient group.

Extracellular matrix proteins protect small cell lung cancer cells against apoptosis: a mechanism for small cell lung cancer growth and drug resistance in vivo

Resistance to chemotherapy is a principal problem in the treatment of small cell lung cancer (SCLC). We show here that SCLC is surrounded by an extensive stroma of extracellular matrix (ECM) at both primary and metastatic sites. Adhesion of SCLC cells to ECM enhances tumorigenicity and confers resistance to chemotherapeutic agents as a result of beta1 integrin-stimulated tyrosine kinase activation suppressing chemotherapy-induced apoptosis. SCLC may create a specialized microenvironment, and the survival of cells bound to ECM could explain the partial responses and local recurrence of SCLC often seen clinically after chemotherapy. Strategies based on blocking beta1 integrin-mediated survival signals may represent a new therapeutic approach to improve the response to chemotherapy in SCLC.

Initial serum ferritin levels in patients with multiple trauma and the subsequent development of acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) represents a catastrophic form of inflammatory lung injury that occurs unpredictably in some, but not all, at-risk patients. In this study, we investigated serum ferritin as a marker for ARDS development in a homogenous group of patients at-risk because of multiple trauma. We hypothesized that since ferritin synthesis is increased by proinflammatory cytokines, which are increased and implicated in ARDS, that ferritin levels would increase and that ferritin increases would correlate with the degree of inflammation and therefore the development of ARDS. We studied 42 patients (25 male, 17 female) who as a consequence of multiple trauma became at-risk for developing ARDS. Using the European/American Consensus definition for ARDS, 16 (38%) patients subsequently developed ARDS (11 male and five female). We found that initial serum ferritin levels correlated with the subsequent development of both ARDS (progression to ARDS, median = 638 ng/ml; (range, 70 to 4,500) versus nonprogression to ARDS = 185 ng/ml; range, 12 to 2,850) (p = 0.02, r = -0.27) and multiple organ failure (p < 0.05, r = 0.39). Using our previously established cutoff points for serum ferritin, the positive predictive value was 62% for men and 75% for women. Initial serum ferritin levels also correlated with a measurement of the degree of initial trauma injury, i.e., the injury severity score (ISS) (p < 0.05, r = 0.37). However, there was no correlation between serum ferritin levels and other markers of clinical injury, namely, lowest PaO2/FIO2 ratio (p = 0.67), days requiring ventilation (p = 0.09), or mortality (p = 0.42). A significant association existed between serum ferritin levels and products of endothelial activation, i.e., sE-selectin (p < 0.04, r = 0.37) and sICAM-1 (p < 0.01, r = 0.21). In the future, with the development of novel anti-inflammatory therapies, early identification of specific high-risk patients would allow the institution of these therapies and thereby increase the chances of reducing ARDS morbidity and mortality.

Secretory leukocyte proteinase inhibitor is preferentially increased in patients with acute respiratory distress syndrome

Inappropriate release of proteases from inflammatory and stromal cells can lead to destruction of the lung parenchyma. Antiproteinases such as alpha-1-proteinase inhibitor (alpha1-Pi), secretory leukocyte proteinase inhibitor (SLPI) and elastase-specific inhibitor (elafin) control excess production of human neutrophil elastase. In the present study, the concentrations of alpha1-Pi, SLPI and elafin found in bronchoalveolar lavage (BAL) fluid from control subjects, patients at risk of developing acute respiratory distress syndrome (ARDS) and patients with established ARDS were determined. Levels of all three inhibitors were raised in patients compared with normal subjects. SLPI was increased in the group of patients who were at risk of ARDS and went on to develop the condition, compared with the "at-risk" group who did not progress to ARDS (p=0.0083). Alpha1-Pi and elafin levels were similar in these two populations. In patients with established ARDS, both alpha1-Pi and SLPI levels were significantly increased, compared to patients at risk of ARDS who did (p=0.0089) or did not (p=0.0003) progress to ARDS. The finding of increased antiproteinases shortly before the development of acute respiratory distress syndrome provide further evidence for enhanced inflammation prior to clinical disease.

Neutrophil chemokines in bronchoalveolar lavage fluid and leukocyte-conditioned medium from nonsmokers and smokers

Polymorphonuclear neutrophils (PMN) have been implicated in the pathogenesis of emphysema. The chemokines interleukin-8(IL-8), growth-related oncogene (GRO-alpha) and extractable nuclear antigen (ENA)-78 may be involved in the increased numbers of PMN in smokers' airspaces. The levels of these cytokines in bronchoalveolar lavage fluid (BALF) and bronchoalveolar lavage leukocyte conditioned medium (LCM), along with BALF PMN numbers in 12 smokers who abstained for 12 h (chronic smoking) or continued to smoke until I h before study (acute smoking) and seven nonsmokers were compared. Neutrophils in BALF increased in acute (1.96+/-0.53%, 0.99+/-0.32x10(6) cells) compared with chronic smokers (0.59+/-0.25%, 0.61+/-0.24x10(6) cells, p<0.05 nonsmokers) and nonsmokers (0.79+/-0.29%, 0.05+/-0.01x 10(6) cells, p<0.05). There were no differences in IL-8 or GRO-alpha in BALF between smokers and nonsmokers. ENA-78 levels were lower in smokers (p=0.006). There was no difference in IL-8, GRO-alpha or ENA-78 in LCM from unstimulated cells in smokers versus nonsmokers. After stimulation with lipopolysaccharide (LPS) 10 ng mL(-1), IL-8 release in acute smokers (p=0.04) and GRO-alpha release in smokers (p=0.009) were significantly higher than in nonsmokers. Following stimulation with LPS 100 ng.mL(-1), GRO-alpha release was higher in smokers (p=0.03) and increased further in acute smokers (p=0.02 versus nonsmokers, p=0.04 versus chronic smokers) and ENA-78 release increased in smokers (p=0.02 versus non-smokers). In conclusion, influx of polymorphonuclear neutrophils into smokers' airspaces is an acute phenomenon and neutrophil chemokine release from mixed bronchoalveolar lavage leukocytes is influenced by cigarette smoking and endotoxins.

Human circulating eosinophils secrete macrophage migration inhibitory factor (MIF). Potential role in asthma

Macrophage migration inhibitory factor (MIF) is a potent proinflammatory mediator that has been shown to potentiate lethal endotoxemia and to play a potentially important regulatory role in human acute respiratory distress syndrome (ARDS). We have investigated whether eosinophils are an important source of MIF and whether MIF may be involved in the pathophysiology of asthma. Unstimulated human circulating eosinophils were found to contain preformed MIF. Stimulation of human eosinophils with phorbol myristate acetate in vitro yielded significant release of MIF protein. For example, eosinophils stimulated with phorbol myristate acetate (100 nM, 8 h, 37 degreesC) released 1,539+/-435 pg/10(6) cells of MIF, whereas unstimulated cells released barely detectable levels (< 142 pg/10(6) cells, mean+/-SEM, n = 8). This stimulated release was shown to be (a) concentration- and time-dependent, (b) partially blocked by the protein synthesis inhibitor cycloheximide, and (c) significantly inhibited by the protein kinase C inhibitor Ro-31,8220. In addition, we show that the physiological stimuli C5a and IL-5 also cause significant MIF release. Furthermore, bronchoalveolar lavage fluid obtained from asthmatic patients contains significantly elevated levels of MIF as compared to nonatopic normal volunteers (asthmatic, 797.5+/-92 pg/ml; controls, 274+/-91 pg/ml). These results highlight the potential importance of MIF in asthma and other eosinophil-dependent inflammatory disorders.

Potential pro-inflammatory effects of soluble E-selectin upon neutrophil function

Appropriate recruitment of neutrophils to sites of infection or tissue injury is a key event in the inflammatory response. A number of studies have shown the critical role of selectins in tethering and rolling of neutrophils on vascular endothelium, as well as a more complex regulatory role, since they have the potential to alter leukocyte recruitment by triggering beta2 integrin-mediated adhesion. In this study, we report that in contrast to patients "at risk" of developing acute respiratory disease syndrome (ARDS), elevated plasma levels of soluble E-selectin are found in patients with established disease. Since neutrophil granulocytes are implicated in ARDS pathogenesis, we have investigated the possibility of a link between elevated soluble plasma E-selectin levels and disease progression by examining the effects of soluble recombinant E-selectin (E-zz) upon neutrophil function. In this paper, we describe the novel finding that exposure of neutrophils to E-zz potentiates a number of neutrophil functions which may act to drive inflammatory processes. Although neutrophil deformability, an important parameter determining retention within the lung microvasculature, was not affected by E-zz, neutrophil polarization was observed. In addition, neutrophil beta2 integrin-mediated adhesion was found to be augmented by E-zz without alteration in levels of surface expression of alphaMbeta2 or the "activation" reporter epitope defined by monoclonal antibody 24. Concomitantly with increased beta2 integrin-mediated adhesion, we observed an inhibition of formyl-Met-Leu-Phe-directed chemotaxis. Together with an augmentation of neutrophil reactive oxidant species production and release of superoxide anions, these data raise the possibility that soluble E-selectin exerts pro-inflammatory effects upon neutrophil function at sites of inflammation, thereby exacerbating disease processes.

Macrophage migration inhibitory factor: a regulator of glucocorticoid activity with a critical role in inflammatory disease

Macrophage migration inhibitory factor (MIF) was one of the first cytokines to be identified. In the early 1990s it was 'rediscovered' as a hormone that is secreted by the anterior pituitary gland and counter-regulates the anti-inflammatory effects of glucocorticoids. We now know that glucocorticoids stimulate the release of MIF from T cells and macrophages; this appears to be a physiological response to override the effects of glucocorticoids at the inflammatory site. However, this response can become pathological in acute respiratory distress syndrome (ARDS), in which high concentrations of MIF in the alveoli might contribute to ARDS pathogenesis. New insights into the structure and function of MIF, and the possibility of increasing the efficacy of glucocorticoids in the clinic by inhibiting MIF, are discussed in this review.