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IL-17A and IL-17F are both involved in the pathogenesis of neutrophilic inflammation observed in COPD and severe asthma. To explore this, mice deficient in both Il17a and Il17f and wild type (WT) mice were exposed to cigarette smoke or environmental air for 5 to 28 days and changes in inflammatory cells in bronchoalveolar lavage (BAL) fluid were determined. We also measured the mRNA expression of keratinocyte derived chemokine (Kc), macrophage inflammatory protein-2 (Mip2), granulocyte-macrophage colony stimulating factor (Gmcsf) and matrix metalloproteinase-9 (Mmp9 ) in lung tissue after 8 days, and lung morphometric changes after 24 weeks of exposure to cigarette smoke compared to air-exposed control animals. Macrophage counts in BAL fluid initially peaked at day 8 and again on day 28, while neutrophil counts peaked between day 8 and 12 in WT mice. Mice dual deficient with Il17a and 1l17f showed similar kinetics with macrophages and neutrophils, but cell numbers at day 8 and mRNA expression of Kc, Gmcsf and Mmp9 were significantly reduced. Furthermore, airspaces in WT mice became larger after cigarette smoke exposure for 24 weeks, whereas this was not seen dual Il17a and 1l17f deficient mice. Combined Il17a and Il17f deficiency resulted in significant attenuation of neutrophilic inflammatory response and protection against structural lung changes after long term cigarette smoke exposure compared with WT mice. Dual IL-17A/F signalling plays an important role in pro-inflammatory responses associated with histological changes induced by cigarette smoke exposure.

Abstract: Immune checkpoint inhibitors (ICIs) have emerged as evolutionary treatments for malignant diseases. Although ICIs can cause immune-related adverse events (irAEs) in various organs, precise timing after ICI initiation has been scarcely reported. Elucidating the effects of irAEs, such as time to onset, involvement of major organs, influence on progression-free survival (PFS), and overall survival (OS), are critical issues for physicians. Furthermore, lung-irAE as a whole is not well known.We conducted a retrospective study of 156 patients who were treated with ICIs and compared 82 irAE patients with 74 non-irAE patients.This study clearly demonstrated that the preferred period after induction of ICIs was significantly longer in lung-irAE than in other major organs (skin, digestive tract, and endocrine). The effect of irAEs on PFS and OS was evident PFS in the irAE group (n = 82) (median 128 days, interquartile range [IQR] 62-269 days, P = .002) was significantly longer than that in the non-irAE group (n = 74) (median 53 days, IQR 33-151 days). Similarly, OS was significantly longer in the irAE group (median 578 days, IQR 274-1027 days, P = .007) than in the non-irAE group (median 464 days, IQR: 209-842 days). However, this positive effect of irAEs in the lungs was not proportional to the extent of severity.Lung-irAEs can occur at a later phase than non-lung-irAEs and seemed not to prolong OS and PFS. However, further studies are needed to support these findings., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: The galaxy sign is an irregularly marginated pulmonary nodule formed by a confluence of multiple small nodules, and it is a diagnostic radiological finding for pulmonary sarcoidosis. However, the clinical significance of the galaxy sign for sarcoidosis has been poorly investigated., Objective: This study aimed to investigate the clinical significance and detailed radiological features of the galaxy sign in patients with pulmonary sarcoidosis., Methods: We retrospectively reviewed 87 patients with biopsy-proven sarcoidosis and 108 patients with pulmonary tuberculosis. Galaxy sign incidence was assessed on thoracic high-resolution computed tomography (HRCT) images from each group. Correlations of galaxy sign with clinical characteristics and disease outcomes were evaluated for patients with sarcoidosis., Results: HRCT findings were available for 65 of 87 patients with pulmonary sarcoidosis and all 108 patients with pulmonary tuberculosis. Galaxy sign incidence was significantly higher in patients with pulmonary sarcoidosis (n=15, 23.1%) than in those with pulmonary tuberculosis (n=2, 1.9%, p<0.001). Among the 65 patients with pulmonary sarcoidosis, those with galaxy signs (n=15) were significantly younger (median: 32 years, interquartile range [IQR] 28-38 years) than those without (n=50) (median: 62 years, IQR 37.7-73 years). The CD4/CD8 ratio in bronchoalveolar lavage fluid (BALF) was also significantly lower in the former group (median: 2.6, IQR 2.0-3.9 vs. median 5.8, IQR 3.7-8.6, p<0.001)., Conclusion: Galaxy signs are associated with younger age and low BALF CD4/CD8 ratio but not disease severity.

The mortality and morbidity of chronic obstructive pulmonary disease are high. However, no radical therapy has been developed to date. The purpose of this study was to evaluate whether fetal mouse lung tissue can grow and differentiate in the emphysematous lung. Fetal lung tissue from green fluorescent protein C57BL/6 mice at 16 days' gestation was used as donor material. Twelve-month-old pallid mice were used as recipients. Donor lungs were cut into small pieces and implanted into the recipient left lung by performing thoracotomy under anesthesia. The recipient mice were sacrificed at day 7, 14, and 28 after implantation and used for histological examination. Well-developed spontaneous pulmonary emphysema was seen in 12-month-old pallid mice. Smooth and continuous connection between implanted fetal lung tissue and recipient lung was recognized. Air space expansion and donor tissue differentiation were observed over time. We could clearly distinguish the border zones between injected tissue and native tissue by the green fluorescence of grafts. Fetal mouse lung fragments survived and differentiated in the emphysematous lung of pallid mice. Implantation of fetal lung tissue in pallid mice might lead to further lung regeneration research from the perspective of respiratory and exercise function. J. Med. Invest. 63: 182-186, August, 2016.

The impacts of air pollution on human health and disease have been attracting attention, especially in industrialized countries and areas with heavy traffic burdens. Fine particulate matters (PMs) are considered as an important air pollutant, since it was reported that there was a significant relationship between PM2.5 levels and mortality by cohort studies in 1990s. Epidemiological and toxicological studies have strongly suggested a causative relationship between fine particulate air pollution and increased incidence as well as exacerbations of asthma, and other respiratory disorders. Recent advances in research have elucidated that PMs primarily and secondarily induce oxidative stresses which result both in pro- and antiinflammatory activities. It has been demonstrated that gene polymorphisms of antioxidant enzymes might change responses to particulate air pollution exposures. To prevent health hazardous effects of particles, it is crucial to screen susceptible subpopulations and establish chemoprevention strategies in the world. Novel techniques and modalities are patented for future progress on better control of air pollution.

Background: The presence of "mechanic's hands" is one of the clinical clues for collagen vascular diseases. However, the exact relevance of "mechanic's hands" in collagen vascular diseases has not been well documented. The aim of this study was to clarify the relevance of "mechanic's hands" to collagen vascular diseases including various skin lesions and interstitial pneumonia., Methods: A retrospective review of the medical records of patients with "mechanic's hands" at our hospital between April 2011 and December 2012 was conducted. A PubMed search was also conducted using the term "mechanic's hands"., Results: Four patients in our institution and 40 patients obtained from PubMed who had "mechanic's hands" were identified. The most frequent diseases were DM/amyopathic DM (n = 24, 54.5%) and anti-ARS syndrome (n = 17, 38.6%). In these patients, the major skin lesions associated with "mechanic's hands" were periungual erythema (n = 23, 52.3%), Gottron's sign (n = 17, 38.6%), heliotrope rash (n = 10, 22.7%), Raynaud's phenomenon (n = 9, 20.5%), and anti-ARS syndrome (n = 17, 38.6%). Six cases (2 DM, 4 anti-ARS syndrome) had only "mechanic's hands". Antibodies to anti-ARS (n = 24) were Jo-1 (n = 19), PL-7 (n = 3), OJ (n = 1), and PL-12 (n = 1)., Conclusion: The presence of "mechanic's hands" together with diverse skin lesions could be a clinical clue to the diagnosis of lung involvement associated with collagen vascular diseases, especially in anti-ARS syndrome or DM/amyopathic DM.

Airway and pulmonary fibrosis is a pathological condition associated with chronic airway inflammation. Fibrosis and architectural remodeling of tissues can severely disrupt lung function, often with fatal consequences. The traditional paradigm of fibrogenesis is based on the activation of local stromal cells including fibroblasts and their conversion into myofibroblasts. However, it has become apparent that several airway structural cells, including epithelial cells, endothelial cells, and pericytes, contribute to lung fibrosis through a process of molecular reprogramming. Recent studies have shown the important role of epithelial-mesenchymal transition (EMT) in airway diseases and animal models of fibrosis, suggesting that targeting EMT may be a promising strategy against fibrotic lung disease. In this article, we review the latest advances on the evidence for EMT in airway diseases, and discuss the underlying mechanisms of EMT and the roles of inflammatory mediators. We also describe recent patents that could develop into novel therapeutics.

Mycoplasma pneumoniae (Mp) may cause immune cell reactions as pivotal aspects of this clinically common respiratory pathogen. Our aim is to determine if Mp extract induces a cellular immune response associated with interleukin (IL)-17, leading to lung inflammation and lung injury. BALB/c mice were immunized with Mp extract intraperitoneally followed by its intratracheal administration, to mimic repeated Mp infection found in humans (repeated inoculation, RI group). Those with a single inoculation were compared as single inoculation group (SI group). Analysis of bronchoalveolar lavage fluid (BALF) demonstrated that keratinocyte-derived cytokine, tumor necrosis factor-α, and IL-6 were produced and peaked on days 0.5 or 1, followed by IL-17 on day 2. Levels of these mediators in BALF were higher in RI group than SI group (P < 0.05). Further, significantly more neutrophils were recruited to the lungs of the RI group (P < 0.05). These observations suggest that IL-17 is involved in the prolonged induction of neutrophils in mice treated with Mp extract.

Two cases of rheumatoid nodules evaluated by fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and video-assisted thoracic surgery (VATS) biopsy are reported. The first case was that of a 44-year-old woman who presented with a cavitated nodule with intense standardized uptake values (SUVs) both in the early (max 3.4) and delayed (max 4.4) phases, suggesting malignancy. However, after VATS biopsy, she was diagnosed as having a rheumatoid nodule with vasculitis. The second case was that of a 74-year-old woman admitted with bilateral lung nodules, two of which showed intense early (max 2.2) and delayed (max 6.0) phase SUVs, and mild early (max 0.6) and delayed (max 0.9) phase SUVs. These two nodules were finally proven to be a lung cancer and rheumatoid nodule without vasculitis, respectively. These cases show that rheumatoid nodules with an enhanced inflammatory process, such as vasculitis, can appear false-positive for malignancy on FDG-PET/CT scan images.

Background: Gemcitabine (GEM) is widely used as a chemotherapeutic agent. However, pulmonary toxicity has been rarely observed with GEM use. This article aims to determine the incidence and causes of drug-induced pulmonary toxicity, and to classify the high-resolution computed tomography (HRCT) findings for antitumor therapy-associated pulmonary toxicity based on characteristic patterns and pathological considerations, with a special focus on GEM-associated pulmonary toxicity (GAPT)., Methods: Medical records of all patients with drug-induced pulmonary toxicity seen at Kyorin University hospital between April 2006 and December 2011 were retrospectively reviewed. The study examined correlations between HRCT and the assessed pathological or clinical findings, with a specific focus on antitumor drugs., Results: We identified 66 patients with drug-induced pulmonary toxicity. Among the antitumor drugs, GEM was the primary offending agent (n = 8) for pulmonary toxicity followed by docetaxel and gefitinib. HRCT patterns for the eight GAPT patients included the non-specific interstitial pneumonia (NSIP; n = 5) and the hypersensitivity pneumonitis (HP)-like pattern (n = 3). In contrast, four patients in the study were found to have the HP-like pattern, with three cases associated with GEM and one case associated with imatinib mesylate. The transbronchial lung biopsy or video-assisted thoracic surgery specimens for these patients showed granuloma or organizing tissue with a random distribution that was independent of the respiratory bronchiole. These results appeared to correspond to the HRCT-determined centrilobular nodules., Conclusion: GEM was the leading cause of drug-induced pulmonary toxicity in the patients examined in this study. This toxicity appears as NSIP or an HP-like pattern during HRCT examinations. This HP-like pattern may be useful for diagnosing GEM-induced pulmonary toxicity, as well as demonstrating granuloma or organizing tissue during lung pathology examinations.

Background: The saw-tooth sign was first described by Sanders et al in patients with obstructive sleep apnea syndrome as one cause of extrathoracic central airway obstruction. The mechanism of the saw-tooth sign has not been conclusively clarified. The sign has also been described in various extrathoracic central airway diseases, such as in burn victims with thermal injury to the upper airways, Parkinson's disease, tracheobronchomalacia, laryngeal dyskinesia, and pedunculated tumors of the upper airway., Case Presentation: A 61-year-old man was referred to our hospital with a two-month history of persistent dry cough and dyspnea. He was diagnosed with lung cancer located in an intrathoracic central airway, which was accompanied by the saw-tooth sign on flow-volume loops. This peculiar sign repeatedly improved and deteriorated, in accordance with the waxing and waning of central airway stenosis by anti-cancer treatments., Conclusion: This report suggests that the so-called saw-tooth sign may be found even in intrathoracic central airway obstruction due to lung cancer.

Mice with a functional human immune system have the potential to allow in vivo studies of human infectious diseases and to enable vaccine testing. To this end, mice need to fully support the development of human immune cells, allow infection with human pathogens, and be capable of mounting effective human immune responses. A major limitation of humanized mice is the poor development and function of human myeloid cells and the absence of human immune responses at mucosal surfaces, such as the lung. To overcome this, we generated human IL-3/GM-CSF knock-in (hIL-3/GM-CSF KI) mice. These mice faithfully expressed human GM-CSF and IL-3 and developed pulmonary alveolar proteinosis because of elimination of mouse GM-CSF. We demonstrate that hIL-3/GM-CSF KI mice engrafted with human CD34(+) hematopoietic cells had improved human myeloid cell reconstitution in the lung. In particular, hIL-3/GM-CSF KI mice supported the development of human alveolar macrophages that partially rescued the pulmonary alveolar proteinosis syndrome. Moreover, human alveolar macrophages mounted correlates of a human innate immune response against influenza virus. The hIL-3/GM-CSF KI mice represent a unique mouse model that permits the study of human mucosal immune responses to lung pathogens.

Histamine is a potent mediator in allergic inflammatory processes and is released by basophils and mast cells. The aim of this study was to investigate the effect of histamine on in vitro migration of human fetal lung fibroblasts (HFL-1) to human plasma fibronectin (HFn), a chemoattractant. Using the blindwell chamber technique, histamine alone had no chemotactic activity. However, histamine augmented HFn-induced HFL-1 migration at concentrations ranging between 0 and 10(-7) M (290.6 +/- 20.8%) (P < 0.05). The concentration-response was bell-shaped. The effect of histamine increased with time. The stimulatory effect of histamine on HFL-1 migration was inhibited by an H4 receptor antagonist, JNJ7777120 (10(-5) M). Histamine's effect was also inhibited by pertussis toxin (50 ng/ml), showing that the effect was mediated by the H4 receptor. This study demonstrated that histamine has the potential to stimulate human lung fibroblast migration, and thus may contribute to regulation of wound healing and the development of fibrotic disorders of the lung.

Fibroblasts are important cells that are involved in modulation of fibrosis after injuries. In some uncontrollable inflammatory processes, excess fibroblasts migrate around the small airway. The pathogenesis of chronic obstructive pulmonary disease is related to fibrosis around the small airways. The aim of the current study was to investigate the effect of procaterol, a second-generation beta (2)-agonist, on migration of human fetal lung fibroblasts (HFL-1) induced by human plasma fibronectin (HFn). Using the blindwell chamber technique, 10(-8) M procaterol inhibited migration of HFL-1 (control, 100%; 10(-8) M, 73.2 +/- 4.9%; n = 6, p < 0.05). The inhibitory effect of procaterol was concentration-dependent. Although a beta 2-receptor inhibitor, ICI 181551, blocked the inhibitory effect of procaterol, a beta 1-receptor inhibitor, atenolol, did not. Because a cyclic AMP-dependent protein kinase (PKA) inhibitor, KT5720, blocked the effect of procaterol, the cyclic AMP-PKA pathway may be involved in the migration inhibitory process. Procaterol, which is prescribed mainly for treatment of bronchial asthma, might be a useful drug for inhibiting lung fibrosis following injuries to the lung.

C-reactive protein (CRP) has been classically used as a marker of inflammation. The aim of this study was to investigate the effect of CRP on migration of human fetal lung fibroblasts (HFL-1) to human plasma fibronectin (HFn). Using the blindwell chamber technique, CRP inhibited HFL-1 migration in a dose-dependent fashion (at 1 microg/mL, inhibition: 32.5% +/- 7.1%; P < .05). Western blot analysis showed that CRP inhibited the p38 mitogen-activated protein kinase (MAPK) activity in the presence of HFn. Moreover, the MAPK inhibitors SB202190 (25 microM) and SB203580 (25 microM) inhibited HFn-induced cell migration, suggesting an important role of p38 MAPK in HFn-induced migration. Taken together, these results suggest that the inhibitory effect of CRP is mediated by blocking MAPK. In summary, this study demonstrates that CRP directly modulates human lung fibroblasts migration. Thus, CRP may contribute to regulation of wound healing and may be endogenous antifibrotic factor acting on lung fibrosis.

The authors used BALB/c and C57BL/6 mouse strains to search for genetically based differences in response to prolonged (6 months) low-dose (100 microg/m3) diesel exhaust particle (DEP) exposure from birth in terms of airway inflammatory responses. Histopathological assessment showed that inflammatory cells infiltrated the perivascular areas only in C57BL/6 mice. The count of DEP-laden alveolar macrophages in bronchoalveolar lavage (BAL) fluid was significantly greater in BALB/c mice (P < .05) than in C57BL/6 mice. The lymphocyte and eosinophil count in BAL fluid was significantly greater in C57BL/6 mice (P < .05) than in BALB/c mice. Immunoglobulin (Ig) IgG1 and IgG2 levels in serum, and the monocyte chemoattractant protein (MCP)-1 level in BAL fluid were significantly greater in BALB/c mice than in C57BL/6 mice. The interleukin (IL)-12 level in BAL fluid was significantly greater in C57BL/6 mice than in BALB/c mice, but the IL-13 level in BAL fluid was significantly less in BALB/c mice than in C57BL/6 mice. Glutathione S-transferase (GST) mRNA expression and protein production in lung tissues were significantly lower in C57BL/6 mice than in BALB/c mice, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) level in the lung tissues were significantly greater in C57BL/6 mice than in BALB/c mice. In conclusion, prolonged low-dose DEP exposure induces airway inflammatory responses that differ remarkably among mouse strains; these differences are caused by differences in the host defense response to the oxidative stress induced by DEP exposure and may be useful in the development of biomarkers.

Objective: The capability of regeneration of lung tissues in adults is limited after chronic destruction. Bone marrow-derived stem cells, retinoic acid, growth factors, and other approaches have been attempted to promote or facilitate this process. We hypothesized that fetal lung tissues, with great potential for growth and differentiation, could be used for lung regeneration., Methods: Day 17 fetal lung tissue fragments at the pseudoglandular stage of lung development from Lewis rats were implanted into adult Lewis rat lungs. For group 1, fetal lung fragments were injected into the adult left lung parenchyma; for group 2, fetal fragments were injected with the left lung partially resected; for group 3, adult fragments were injected; and for groups 4 and 5, fetal fragments were implanted into the omentum and subcutaneous tissue, respectively., Results: The grafts implanted into pulmonary parenchyma were differentiated with opening of the alveolar space after 4 weeks and were advanced further with morphologic features similar to those of neonatal lungs after 8 and 12 weeks. The implants were connected with pulmonary circulation determined by means of perfusion with India ink. These changes appeared to be further enhanced in animals with partial lung resection that might have facilitated the maturation of implanted fetal lung tissues through mechanical factors, soluble factors, or both. Fetal lung tissues did not mature when implanted into the omentum or subcutaneous tissue. Adult lung fragments did not expand after being reimplanted back into the same animal., Conclusions: Fetal lung tissue might be an option for further investigation into lung regeneration.

The authors investigated the effects of inhalation of diesel exhaust (DE) on murine mycobacterial infection in vivo. Eight-week-old female BALB/c mice were exposed to DE (3 mg/m3 of diesel exhaust particles [DEPs]) for 1 month, 2 months, or 6 months (for 7 hours a day, 5 days a week). Control mice were housed in a clean room for the same periods. On the day following the last DE exposure, control mice and DE-exposed mice were aerially infected with Mycobacterium tuberculosis (1 x 10(6) colony-forming units (CFU), Kurono strain). At 7 weeks after mycobacterial infection, the authors examined the lung tissues for histopathological changes and performed reverse transcriptase-polymerase chain reaction (RT-PCR) to measure the messenger RNA (mRNA) expression of several proinflammatory cytokines and inducible nitric oxide synthase (iNOS). Then, the homogenates of lungs and spleens were cultured on 1% (v/v) Ogawa's egg slant medium, and after a 4-week incubation period at 37 degrees C, colonies on the medium were counted. After 1 month of DE exposure, the mycobacterial infection had slightly ameliorated. After 2 months of DE exposure, the expression levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-12p40, interferon (IFN)-gamma, and iNOS mRNAs were slightly increased. However, after 6 months of DE exposure, the expression levels of IL-1beta , IL-12p40, IFN-gamma, and iNOS mRNAs were decreased, and the infection as measured by increased lung burden (CFU) actually increased. These results indicate that long-term DE exposure may increase pulmonary mycobacterial burden.

The authors investigated the effects of exposure to diesel exhaust (DE) on murine lung tissues in vivo. BALB/c and C57BL/6 mice were exposed to DE with low (100 microg/m(3)) and high (3 mg/m(3)) DE particle levels for 3 months. The authors then examined morphological changes and the expression of mRNAs for various cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta, IL-4, IL-6, IL-10, IL-12p40, and interferon [IFN]-gamma) and inducible nitric oxide synthase (iNOS) in the lungs, as well as TNF-alpha, IL-1beta, IL-10, IL-12p40, and Mac-1 mRNA expression in alveolar macrophages (AMs). TNF-alpha, IL-12p40, IL-4, and IL-10 mRNA expression were mildly increased, whereas IL-1beta mRNA and iNOS expression were slightly decreased, in the low- and high-level exposure groups. Flow cytometry of bronchoalveolar lavage fluid revealed a significant increase in Mac-1-positive cells in the high-level exposure group. On histological examination, bronchus-associated lymphoid tissue (BALT), containing B and T lymphocytes, had developed only in the high-level exposure group. Chronic inhalation of DE influences cytokine expression in the murine lung, and induces phagocytosis and BALT development. These findings suggest that DE may provoke immunological responses by acting as a foreign body in the lung, and that even low-level exposure may induce allergic reactions.

Background: Asthma is characterized by chronic inflammation of the airway with the presence of Th2 cytokines. Airway remodeling in asthma is closely related to clinical manifestations. Lung myofibroblasts play a critical role in the airway remodeling and Th2 cytokines may modulate their behavior. We examined the effect of two major Th2 cytokines, IL-4 and IL-13, on differentiation of lung fibroblasts to myofibroblasts. We hypothesized that these cytokines would stimulate fibroblast proliferation in association with decreased prostaglandin E(2) (PGE(2))., Methods: Lung fibroblasts were incubated with IL-4 and IL-13 with or without Th1 cytokine interferon-gamma (IFN-gamma) in vitro. Differentiation of lung fibroblasts to myofibroblasts was characterized by the expression of alpha-smooth muscle actin (alpha-SMA) as well as a morphological and immunohistochemical analysis. Fibroblast proliferation stimulated by IL-4 and IL-13 was assessed with the MTT assay. We also investigated the effect of these cytokines on cyclooxygenase (COX) gene expression and PGE(2) production., Results: IL-4 and IL-13 increased alpha-SMA expression and myofibroblastic differentiation. This effect was attenuated by IFN-gamma and dexamethasone failed to have an influence on differentiation. IL-4 and IL-13 stimulated fibroblast proliferation. These cytokines downregulated the expression of both COX-1 and COX-2 genes and decreased the production of PGE(2)., Conclusions: IL-4 and IL-13 induce differentiation of fibroblasts to myofibroblasts and this response is attenuated by IFN-gamma. IL-4 and IL-13 stimulate fibroblast proliferation and this effect is at least partly due to suppressed COX gene expressions and subsequently decreased PGE(2) production. These findings suggest that IL-4 and IL-13 directly act on lung fibroblast to induce a fibrogenic response., (Copyright 2003 S. Karger AG, Basel)

The authors investigated the effect of diesel exhaust (DE) on cytokine expression in murine lung tissues. BALB/c mice were exposed to DE for 1 month at different dose levels of DE (low dose: diesel exhaust particles [DEP] 100 micro g/m(3); high dose: 3mg/m(3)). After exposure, the authors examined mRNA expression of cytokines (tumor nocrosis factor alpha [TFN-alpha], Interleukin [IL]-1beta, IL-4, IL-6, IL-10, IL-12p40, and interferon gamma [IFN-gamma] and inducible nitric oxide synthase (iNOS) in the lung, and also measured the secretion of TNF-alpha and IL-10 protein by alveolar macrophages (AM). The mRNA expression levels of inflammatory cytokines (TNF-alpha, IL-1beta, IL-6, IL-12p40, IFN-gamma) and iNOS, which are important for host defense, were suppressed significantly. However, the IL-10 mRNA level was increased by DE exposure. The IL-4 mRNA level was increased by low-dose DE exposure but suppressed by high-dose DE exposure. TNF-alpha and IL-10 secretion by AM paralleled mRNA expression. Chronic inhalation of DE affects cytokine expression in murine lung. These results suggest that DE alters immunological responses in the lung and may increase susceptibility to pathogens, and that increased IL-4 expression by low-dose DE exposure may induce allergic reaction such as asthma.

Therapies that mitigate the fibrotic process may be able to slow progressive loss of function in many lung diseases. Because cyclic adenosine monophosphate is known to regulate fibroblasts, the current study was designed to evaluate the activity of selective phosphodiesterase (PDE) inhibitors on two in vitro fibroblast responses: chemotaxis and contraction of three-dimensional collagen gels. Selective PDE4 inhibitors, rolipram and cilomilast, each inhibited the chemotaxis of human fetal lung fibroblasts (HFL-1) toward fibronectin in the blindwell assay system (control: 100% versus cilomilast [10 microM]: 40.5 +/- 7.3% versus rolipram: [10 microM] 32.1 +/- 2.7% cells/5 high-power fields; P < 0.05, both comparisons). These PDE4 inhibitors also inhibited contraction of three-dimensional collagen gels (control: 100% versus cilomilast: 167.7 +/- 6.9% versus rolipram: 129.9 +/- 1.9% of initial size; P < 0.05, both comparisons). Amrinone, a PDE3 inhibitor, and zaprinast, a PDE5 inhibitor, had no effect in either system. Prostaglandin E(2) (PGE(2)) inhibited both chemotaxis and gel contraction, and the PDE4 inhibitors shifted the PGE(2) concentration-dependence curve to the left in both systems. The inhibition of endogenous PGE(2) production by indomethacin diminished the effects of the PDE4 inhibitors in both chemotaxis and gel contraction, consistent with the concept that the PDE4 inhibitory effects on fibroblasts are related to the presence of cyclic adenosine monophosphate in the cells. In summary, these in vitro results suggest that PDE4 inhibitors may be able to suppress fibroblast activity and, thus, have the potential to block the development of progressive fibrosis.

Airway epithelial cells (AEC) are known to play an integral role in the airway defense mechanism via mucociliary system as well as mechanical barriers. Recent studies further indicate that AEC can produce and release biologically active compounds including lipid mediators, growth factors, endothelin and a variety of cytokines/chemokines important in the pathogenesis of airway disorders. Human bronchial epithelial cells were isolated from normal and diseased states, and purely cultured in hormonally defined, serum-free medium. Culture supernatants of AEC contained detectable amounts of cytokines such as IL-1, IL-6, IL-8, G-CSF and GM-CSF. Proinflammatory cytokines IL-1 and TNFalpha generally upregulated expression and release of these cytokines. Moreover, human bronchial epithelial cells from patients with airway diseases such as asthma showed increased levels of mRNA for the cytokines. AEC are considered to interact with immune and inflammatory cells by direct adhesion as well as by humoral factors including cytokines. For example, eosinophil adhesion to AEC may be an important signal for the activation and degranulation of eosinophils. AEC is also believed to take part in the airway mucosal immunity by interacting with lymphocytes. Finally, AEC may play a crucial role in the processes of airway remodelling found in chronic airway inflammatory diseases. These findings strongly suggest that AEC are actively involved as regulators of airway inflammatory responses playing an important role in the pathogenesis of airway disorders, and become a target for therapeutic intervention.

A 26-year-old man was admitted to our hospital for evaluation of cavitary lesions on his chest X-ray film. Chest CT and conventional tomograms showed multiple cavities in both lung fields, as well as hilar and mediastinal lymphadenopathy. He had uveitis and the laboratory data showed a high level of angiotensin converting enzyme in the serum. Histological findings of the specimen obtained by transbronchial lung biopsy showed non-caseating epithelioid cell granuloma, consistent with sarcoidosis. Corticosteroid therapy (prednisolone 40 mg/day) resulted in reduction of the cavitary lesions and the lymphadenopathy. Negative bacteriological studies and the clinical course strongly suggested primary cavitation, a relatively rare form of pulmonary parenchymal involvement in sarcoidosis.

Three-dimensional CT images of six inflated lung specimens (4 lung cancer, 1 bronchiectasis, 1 hamartoma) were reconstructed from contiguous serial sections to study some probable problems in the clinical application of the technique. Optimal thickness and space of sections were evaluated, and contiguous 1.5-mm serial sections were found to provide a clear 3-D image with high fidelity. It was difficult to set a proper threshold to create clear images because a wide CT window is inconsistent with low noise. The images of tubular and linear structures such as from bronchi and vessels demonstrated higher resolution when reconstructed from scanning in the more perpendicular cross-sectional direction to their axis. Although 3-D images obtained here were not as clear as expected, technological advances such as helical CT or MRI may provide 3-D images with sufficient resolution to be applied clinically.

Interaction between lung fibroblasts and airway epithelial cells may play an important role in lung morphogenesis and airway repair after injury. Even though many reports have suggested that mesenchymal fibroblasts have a growth stimulatory effect on surrounding epithelial cells, very few have attempted to confirm and characterize the growth stimulatory activity in isolated cell systems. We cultured human fetal lung (HFL-1) fibroblasts, harvested supernatant-conditioned media under serum-free conditions, and examined their growth stimulatory effect on bovine bronchial epithelial cells by a variety of techniques, including direct enumeration, thymidine uptake, and metaphase arrest. We also partially characterized the growth stimulatory activity and examined the effect of an inhibitor of DNA synthesis on its release. The results demonstrate that HLF-1 fibroblasts release growth stimulatory activity for bovine bronchial epithelial cells. This activity is nondialyzable, protease-sensitive, acid-stable, and lipid-inextractable and thus appears to have the property of protein; it may be produced by de novo synthesis. Molecular sieve chromatography on Sephadex G-75 indicates an approximate molecular mass of 6,000 D. This growth stimulatory activity is likely to play roles in lung morphogenesis and airway repair after injury.