Experimental respiratory syncytial virus infection of human peribronchial gland cells in vitro.

Respiratory syncytial virus (RSV) is a relevant agent of respiratory tract infections, especially in exacerbations of chronic lung diseases. Peribronchial submucosal glands are the main source of tracheobronchial mucus and therefore of major interest. The authors isolated and cultured human peribronchial gland cells and infected them with RSV. The course of infection was monitored by transmission electron, immuno-, and lectin fluorescence microscopy. Morphology shows virus factories with budding particles within cytoplasmatic vacuoles and virus release after 44 h of infection. Experimental infection of human peribronchial gland cells in primary culture appears to be a suitable model in pulmonary research.

Aberrant mural cell recruitment to lymphatic vessels and impaired lymphatic drainage in a murine model of pulmonary fibrosis.

Pulmonary fibrosis is a progressive disease with unknown etiology that is characterized by extensive remodeling of the lung parenchyma, ultimately resulting in respiratory failure. Lymphatic vessels have been implicated with the development of pulmonary fibrosis, but the role of the lymphatic vasculature in the pathogenesis of pulmonary fibrosis remains enigmatic. Here we show in a murine model of pulmonary fibrosis that lymphatic vessels exhibit ectopic mural coverage and that this occurs early during the disease. The abnormal lymphatic vascular patterning in fibrotic lungs was driven by expression of platelet-derived growth factor B (PDGF-B) in lymphatic endothelial cells and signaling through platelet-derived growth factor receptor (PDGFR)-ß in associated mural cells. Because of impaired lymphatic drainage, aberrant mural cell coverage fostered the accumulation of fibrogenic molecules and the attraction of fibroblasts to the perilymphatic space. Pharmacologic inhibition of the PDGF-B/PDGFR-ß signaling axis disrupted the association of mural cells and lymphatic vessels, improved lymphatic drainage of the lung, and prevented the attraction of fibroblasts to the perilymphatic space. Our results implicate aberrant mural cell recruitment to lymphatic vessels in the pathogenesis of pulmonary fibrosis and that the drainage capacity of pulmonary lymphatics is a critical mediator of fibroproliferative changes.

Submesothelial deposition of carbon nanoparticles after toner exposition: case report.

Inhalation of carbon nanoparticles (CNP) from toner dust has been shown to have impact on the respiratory health of persons exposed. Office printers are known emitters of CNP. We report about a female open office worker who developed weight loss and diarrhoea. Laparoscopy done for suspected endometriosis surprisingly revealed black spots within the peritoneum. Submesothelial aggregates of CNP with a diameter of 31-67 nm were found by scanning and transmission electron microscopy in these tissue specimens. Colon biopsies showed inflammatory bowel disease with typically signs of Crohn disease, but no dust deposits. Transport of CNP via lymphatic and blood vessels after inhalation in the lungs has to be assumed. In this case respiratory symptoms were not reported, therefore no lung function tests were done. We have shown that workers with toner dust exposure from laser printers can develop submesothelial deposition of CNP in the peritoneum. Impact of toner dust exposure on the respiratory health of office workers, as suspected in other studies, has to be evaluated further.

Angiogenic and angiostatic chemokines in idiopathic pulmonary fibrosis and granulomatous lung disease.

BACKGROUND: Angiogenesis-angiostasis balance and leukocyte recruitment are influenced by different concentrations of distinct chemokines. OBJECTIVE: To investigate the relative contribution of angiogenic and angiostatic CXC chemokines to the pathogenesis of idiopathic pulmonary fibrosis (IPF) and granulomatous lung diseases, we examined the in vitro production of an angiogenic chemokine (IL-8), and 2 angiostatic chemokines (IP-10 and MIG) by alveolar macrophages. METHODS: Alveolar macrophages from 16 patients with granulomatous lung diseases [8 with sarcoidosis, 8 with extrinsic allergic alveolitis (EAA)], 16 patients with IPF, and 8 control subjects were cultured for 24 h. IL-8, IL-18, IP-10 and MIG in the culture supernatants were measured by a fluorescent bead-based multiplex technique. RESULTS: In IPF patients, IL-8 was increased and correlated with bronchoalveolar lavage (BAL) neutrophils, whereas the levels of IP-10 and MIG were normal. In sarcoidosis and EAA patients, IL-8, IP-10, and MIG were all increased and IP-10 and MIG correlated with IL-18, a Th1 cytokine, and the percentage and number of BAL lymphocytes. CONCLUSIONS: The difference in the expression of CXC chemokines and a Th1 cytokine may contribute to the different immunopathogenesis, clinical course and responsiveness to treatment of these diseases.

Nanostructural analysis by atomic force microscopy followed by light microscopy on the same archival slide.

Integrated information on ultrastructural surface texture and chemistry increasingly plays a role in the biomedical sciences. Light microscopy provides access to biochemical data by the application of dyes. Ultrastructural representation of the surface structure of tissues, cells, or macromolecules can be obtained by scanning electron microscopy (SEM). However, SEM often requires gold or coal coating of biological samples, which makes a combined examination by light microscopy and SEM difficult. Conventional histochemical staining methods are not easily applicable to biological material subsequent to such treatment. Atomic force microscopy (AFM) gives access to surface textures down to ultrastructural dimensions without previous coating of the sample. A combination of AFM with conventional histochemical staining protocols for light microscopy on a single slide is therefore presented. Unstained cores were examined using AFM (tapping mode) and subsequently stained histochemically. The images obtained by AFM were compared with the results of histochemistry. AFM technology did not interfere with any of the histochemical staining protocols. Ultrastructurally analyzed regions could be identified in light microscopy and histochemical properties of ultrastructurally determined regions could be seen. AFM-generated ultrastructural information with subsequent staining gives way to novel findings in the biomedical sciences.

Chlamydophila spp. infection in horses with recurrent airway obstruction: similarities to human chronic obstructive disease.

BACKGROUND: Recurrent airway obstruction (RAO) in horses is a naturally occurring dust-induced disease mainly characterized by bronchiolitis which shows histological and pathophysiological similarities to human chronic obstructive pulmonary disease (COPD). In human COPD previous investigations indicated an association with Chlamydophila psittaci infection. The present study was designed (1) to clarify a possible role of this infectious agent in RAO and (2) to investigate the suitability of this equine disorder as a model for human COPD. METHODS: Clinico-pathological parameters of a total of 45 horses (25 horses with clinical signs of RAO and 20 clinically healthy controls) were compared to histological findings in lung tissue samples and infection by Chlamydiaceae using light microscopy, immunohistochemistry, and PCR. RESULTS: Horses with clinical signs of RAO vs. controls revealed more inflammatory changes in histology (p = 0.01), and a higher detection rate of Chlamydia psittaci antigens in all cells (p < 0.001) and bronchiolar epithelial cells alone (p < 0.001) by immunohistochemistry. The abundance of chlamydial inclusions increased with the severity of disease. PCR was positive in 60% of horses with RAO vs. 45% of the controls (p = 0.316). OmpA sequencing identified Chlamydophila psittaci (n = 9) and Chlamydophila abortus (n = 13) in both groups with no significant differences. Within the group of clinically healthy horses subgroups with no changes (n = 15) and slight inflammation of the small airways (n = 5) were identified. Also in the group of animals with RAO subgroups with slight (n = 16) and severe (n = 9) bronchiolitis could be formed. These four subgroups can be separated in parts by the number of cells positive for Chlamydia psittaci antigens. CONCLUSION: Chlamydophila psittaci or abortus were present in the lung of both clinically healthy horses and those with RAO. Immunohistochemistry revealed acute chlamydial infections with inflammation in RAO horses, whereas in clinically healthy animals mostly persistent chlamydial infection and no inflammatory reactions were seen. Stable dust as the known fundamental abiotic factor in RAO is comparable to smoking in human disease. These results show that RAO can be used as a model for human COPD.

Co-infection with two Chlamydophila species in a case of fulminant myocarditis.

OBJECTIVE: The aim of this study is to describe a case of fulminant myocarditis caused by co-infection with Chlamydophila pneumoniae and Chlamydophila psittaci in order to facilitate diagnosis and clinical management of patients suffering from this rare but life-threatening condition. DESIGN: Case report. SETTING: Intensive care unit of Innsbruck Medical University. PATIENT: A 24-yr-old patient admitted with septicemia and cardiac failure. INTERVENTIONS: Cardiopulmonary resuscitation, extracorporal membrane oxygenation, implantation of an extracorporal cardiac assist device, and antibiotic treatment with erythromycin. MEASUREMENTS AND MAIN RESULTS: Cp. pneumoniae and Cp. psittaci were identified by means of polymerase chain reaction and electron microscopy in the patient's myocytes. Successful weaning off the ventricular assist device was performed within 2 wks after commencement of antibiotic therapy. CONCLUSIONS: This case report demonstrates co-infection with Cp. pneumoniae and Cp. psittaci to be a hitherto unknown cause of fulminant myocarditis. There is a particular risk of misdiagnosis of viral myocarditis, which must be avoided. Patients should be transferred to a center where extracorporal membrane oxygenation therapy and molecular diagnosis of all members of the family Chlamydiaceae are available.

Synergistically upregulated interleukin-10 production in cocultures of monocytes and T cells after stimulation with respiratory syncytial virus.

BACKGROUND: Respiratory syncytial virus (RSV) is known as a causal factor of severe bronchiolitis in young children. It has also been detected in patients with chronic obstructive pulmonary disease (COPD), a disease that is associated with an increased number of T cells in the bronchial mucosa. Here, we investigated the potential direct interaction between RSV and T cells and its impact on cytokine response. METHODS: Purified human peripheral blood T cells were stimulated with RSV in vitro and analyzed by flow cytometry and fluorescence microscopy. Cytokine expression and release were measured in T cell cultures and in cocultures with peripheral blood monocytes as well as with alveolar macrophages from bronchoalveolar lavage fluid by quantitative real-time PCR and ELISA. RESULTS: It was shown that RSV adhered to the surface of T cells. Stimulation of purified T cells with RSV led to a significant increase in interleukin (IL)-10 mRNA expression after 24 h. Moreover, in cocultures of T cells with monocytes or alveolar macrophages, IL-10 production was synergistically upregulated 24 h after stimulation with RSV. CONCLUSION: These results suggest that RSV can cause an excessive IL-10 response leading to downregulation of antiviral defense mechanisms and reduced elimination of respiratory pathogens when antigen-presenting cells and T cells are simultaneously present on the site of infection. This effect may possibly contribute to high frequencies of respiratory pathogens found in patients with chronic inflammatory airway diseases associated with increased local T cell influx such as COPD.

A comparative ultrastructural and molecular biological study on Chlamydia psittaci infection in alpha-1 antitrypsin deficiency and non-alpha-1 antitrypsin deficiency emphysema versus lung tissue of patients with hamartochondroma.

BACKGROUND: Chlamydiales are familiar causes of acute and chronic infections in humans and animals. Human pulmonary emphysema is a component of chronic obstructive pulmonary disease (COPD) and a condition in which chronic inflammation manifested as bronchiolitis and intra-alveolar accumulation of macrophages is common. It is generally presumed to be of infectious origin. Previous investigations based on serology and immunohistochemistry indicated Chlamydophila pneumoniae infection in cases of COPD. Furthermore, immunofluorescence with genus-specific antibodies and electron microscopy suggested involvement of chlamydial infection in most cases of pulmonary emphysema, but these findings could not be verified by PCR. Therefore, we examined the possibility of other chlamydial species being present in these patients. METHODS: Tissue samples from patients having undergone lung volume reduction surgery for advanced alpha-1 antitrypsin deficiency (AATD, n = 6) or non-alpha-1 antitrypsin deficiency emphysema (n = 34) or wedge resection for hamartochondroma (n = 14) were examined by transmission electron microscopy and PCR. RESULTS: In all cases of AATD and 79.4% of non-AATD, persistent chlamydial infection was detected by ultrastructural examination. Intra-alveolar accumulation of macrophages and acute as well as chronic bronchiolitis were seen in all positive cases. The presence of Chlamydia psittaci was demonstrated by PCR in lung tissue of 66.7% AATD vs. 29.0% non-AATD emphysema patients. Partial DNA sequencing of four positive samples confirmed the identity of the agent as Chlamydophila psittaci. In contrast, Chlamydophila pneumoniae was detected only in one AATD patient. Lung tissue of the control group of non-smokers with hamartochondroma was completely negative for chlamydial bodies by TEM or chlamydial DNA by PCR. CONCLUSIONS: These data indicate a role of Chlamydophila psittaci in pulmonary emphysema by linking this chronic inflammatory process to a chronic infectious condition. This raises interesting questions on pathogenesis and source of infection.

Respiratory chlamydial infection based on experimental aerosol challenge of pigs with Chlamydia suis.

An experimental study of aerogeneous challenge in pigs was conducted in order to reveal characteristic features of porcine respiratory chlamydiosis. Eight conventionally raised pigs were exposed to a pathogenic strain of Chlamydia (C.) suis, four controls were mock infected. Besides pathological changes, the acute-phase and humoral immune responses, as well as the dissemination and transmission of the challenge strain was monitored in the course of infection. The data from clinical investigations, LPS-binding protein assay, antibody ELISAs, confocal laser scanning and light microscopy, immunohistochemical staining and PCR provided extensive evidence of the pathogenic potential of C. suis for the porcine respiratory system. This model appears suitable for further pathophysiological and immunological investigations of chlamydial respiratory infections and can also be recommended for studies of Chlamydia-associated infections of the human lung.

Morphology of adenovirus type-3 infection of human respiratory epithelial cells in vitro.

The adenovirus is a non-enveloped DNA virus which may lead to severe diseases of the respiratory tract. In order to study the influence of virus infection on primary cultured peribronchial submucosal gland cells, we performed in vitro infection with human adenovirus type 3. Peribronchial submucosal glands are the main source of tracheobronchial mucus and, therefore, play a major pathophysiological role in common pulmonary diseases such as bronchial asthma, chronic obstructive pulmonary disease and cystic fibrosis. The success of infection was verified by means of immunofluorescence and transmission electron microscopy. Infection follows a certain timetable with a climax of paracristalline intranuclear virus inclusions after 48 h of infection. Virus particles could be detected in the nucleus as well as in peripheral and perinuclear cytoplasmatic vacuoles. The release of virus capsids from the nucleus could be visualized using transmission electron microscopy and immunofluorescence with antibodies against hexon proteins. Two different kinds of mechanisms of transition of newly synthesized virus capsids from the nucleus into the cytoplasm could be identified. Due to an increasing cytopathic effect, viruses spread from cytoplasm after longer terms of infection. Cytopathic effects and cytoskeleton aspects under this virus infection could be characterized using immunofluorescence with several monoclonal antibodies against different cytokeratins.