Antibacterial peptide Reg4 ameliorates Pseudomonas aeruginosa-induced pulmonary inflammation and fibrosis.

Pseudomonas aeruginosa (P. aeruginosa) is a Gram-negative facultative anaerobe that has become an important cause of severe infections in humans, particularly in patients with cystic fibrosis. The development of efficacious methods or mendicants against P. aeruginosa is still needed. We previously reported that regenerating islet-derived family member 4 (Reg4) has bactericidal activity against Salmonella Typhimurium, a Gram-negative flagellated bacterium. We herein explore whether Reg4 has bactericidal activity against P. aeruginosa. In the P. aeruginosa PAO1-chronic infection model, Reg4 significantly inhibits the colonization of PAO1 in the lung and subsequently ameliorates pulmonary inflammation and fibrosis. Reg4 recombinant protein suppresses the growth motility and biofilm formation capability of PAO1 in vitro. Mechanistically, Reg4 not only exerts bactericidal action via direct binding to the P. aeruginosa cell wall but also enhances the phagocytosis of alveolar macrophages in the host. Taken together, our study demonstrates that Reg4 may provide protection against P. aeruginosa-induced pulmonary inflammation and fibrosis via its antibacterial activity.IMPORTANCEChronic lung infection with Pseudomonas aeruginosa is a leading cause of morbidity and mortality in patients with cystic fibrosis. Due to the antibiotic resistance of Pseudomonas aeruginosa, antimicrobial peptides appear to be a potential alternative to combat its infection. In this study, we report an antimicrobial peptide, regenerating islet-derived 4 (Reg4), that showed killing activity against clinical strains of Pseudomonas aeruginosa PAO1 and ameliorated PAO1-induced pulmonary inflammation and fibrosis. Experimental data also showed Reg4 directly bound to the bacterial cell membrane and enhanced the phagocytosis of host alveolar macrophages. Our presented study will be a helpful resource in searching for novel antimicrobial peptides that could have the potential to replace conventional antibiotics.

Influence of miRNA-30a-5p on Pulmonary Fibrosis in Mice with Streptococcus pneumoniae Infection through Regulation of Autophagy by Beclin-1.

The study is aimed at observing the influence of microribonucleic acid- (miRNA-) 30a-50p on the pulmonary fibrosis in mice with Streptococcus pneumoniae infection through the regulation of autophagy by Beclin-1. Specific pathogen-free mice were instilled with Streptococcus pneumoniae through the trachea to establish the pulmonary fibrosis model. Then, they were divided into the miRNA-30a-50p mimics group (mimics group, n = 10) and miRNA-30a-5p inhibitors group (inhibitors group, n = 10), with the control group (n = 10) also set. Pulmonary tissue wet weight/dry weight (W/D) was detected. The content of tumor necrosis factor-α (TNF-α), interleukin- (IL-) 6, and myeloperoxidase (MPO) was determined using enzyme-linked immunosorbent assay (ELISA). Besides, the changes in the pulmonary function index dynamic lung compliance (Cdyn), plateau pressure (Pplat), and peak airway pressure (Ppeak) were monitored, and the gene and protein expression levels were measured via quantitative PCR (qPCR) and Western blotting. The expression level of miRNA-30a-5p was substantially raised in the mimics group (p < 0.05), but extremely low in the inhibitors group (p < 0.05). The mimics group had obviously raised levels of serum aminotransferase (AST), glutamic-pyruvic transaminase (GPT), alkaline phosphatase (ALP), and pulmonary tissue W/D (p < 0.05). Additionally, the expression levels of TNF-α, IL-6, and MPO were notably elevated in the mimics group, while their expression levels showed the opposite conditions in the inhibitors group (p < 0.05). According to the HE staining results, the inhibitors group had arranged orderly cells, while the mimics group exhibited lung injury, pulmonary edema, severe inflammatory response, and alveolar congestion. In the inhibitors group, Cdyn was remarkably elevated, but Pplat and Ppeak declined considerably (p < 0.05). Besides, the inhibitors group exhibited elevated messenger RNA (mRNA) levels of Beclin-1 and LC3, lowered mRNA levels of α-SMA and p62, a raised protein level of Beclin-1, and a markedly decreased protein level of p62 (p < 0.05). Silencing miRNA-30a-5p expression can promote the expression of Beclin-1 to accelerate the occurrence of autophagy, thereby treating pulmonary fibrosis in mice with Streptococcus pneumoniae infection.

Effects of phycocyanin on pulmonary and gut microbiota in a radiation-induced pulmonary fibrosis model.

OBJECTIVE: Radiation pneumonia and fibrosis are major clinical complications of radiotherapy for thoracic tumor patients, and may significantly reduce survival and quality of life. At present, no safe and effective radiation protection measures have been approved for clinical use. Phycocyanin, a protein responsible for photosynthesis from Spirulina, has been shown to have a variety of biological activities and to be beneficial for a variety of diseases, including pulmonary fibrosis. However, the preventive and protective effects of phycocyanin on radiation-induced pulmonary fibrosis have not been studied. DESIGN: X-ray single dose irradiation was used on the chest of mice to prepare a mouse model of pulmonary fibrosis, from which the effect of phycocyanin on pulmonary histopathologic change, pulmonary fibrosis, the microbiota in lung and gut, LPS, TNF-α, and IL-6 at different time after irradiation were evaluated. RESULTS: Phycocyanin alleviated the radiation-induced lung injury and reduced the level of inflammatory factors. Thorax irradiation led to the disorder in microbiota of the lung and gut. The variation trend of the diversity of the two tissues was opposite, but that of the microbiota composition was similar. The phycocyanin intervention regulated the composition of the lung and gut microbiota, transformed them into normal state, and reduced the level of LPS, which significantly reduced the abundance of inflammation-related bacteria, and increased the abundance of probiotics that produce short-chain fatty acids. CONCLUSION: Phycocyanin could regulate the radiation-induced disorder in lung and gut microbiota of mice, and reduce the radiation-induced lung inflammation and fibrosis.

[Emerging bacteria in cystic fibrosis and non-cystic fibrosis bronchiectasis from a microbiologist's perspective]. / Bactéries émergentes dans la mucoviscidose et les dilatations des bronches hors mucoviscidose. Le point de vue du microbiologiste.

INTRODUCTION: Common major pathogens like Pseudomonas aeruginosa are identified in the airways of patients with cystic fibrosis (CF) and non-CF bronchiectasis. However, other opportunistic bacterial pathogens like Achromobacter xylosoxidans complex, Stenotrophomonas maltophilia and non-tuberculous mycobacteria are currently emerging in CF and are also reported in non-CF bronchiectasis. BACKGROUND: The emergence of opportunistic bacterial pathogens has been recognized in CF through annual national reports of sputum microbiology data. Despite common factors driving the emergence of bacteria identified in CF and non-CF bronchiectasis patients, bronchiectasis registries have been created more recently and no longitudinal analysis of recorded microbiological data is currently available in the literature, thereby preventing the recognition of emerging bacteria in patients with non-CF bronchiectasis. OUTLOOK: A longitudinal follow-up of microbiological data is still needed in non-CF bronchiectasis to identify emerging opportunistic bacterial pathogens. Homogeneity in practice of sputum microbiological examination is also required to allow comparative analysis of data in CF and non-CF bronchiectasis. CONCLUSION: Bacterial pathogens recognized as emerging in CF have to be more carefully monitored in non-CF bronchiectasis in view of their association with deterioration of the lung disease.

Enhanced expression of NLRP3 inflammasome components by monocytes of patients with pulmonary paracoccidioidomycosis is associated with smoking and intracellular hypoxemia.

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by thermally dimorphic fungi of the genus Paracoccidioides that affects predominantly 30-60-year-old male rural workers. The main clinical forms of the disease are acute/subacute, chronic (CF); almost all CF patients develop pulmonary fibrosis, and they also exhibit emphysema due to smoke. An important cytokine in this context, IL-1ß, different from the others, is produced by an intracellular multimolecular complex called inflammasome that is activated by pathogens and/or host signs of damage. Inflammasome has been recognized for its contribution to chronic inflammatory diseases, from that, we hypothesized that this activation could be involved in paracoccidioidomycosis, contributing to chronic inflammation. While inflammasome activation has been demonstrated in experimental models of Paracoccidioides brasiliensis infection, no information is available in patients, leading us to investigate the participation of NLRP3-inflammasome machinery in CF/PCM patients from a Brazilian endemic area. Our findings showed increased priming in mRNA levels of NLRP3 inflammasome genes by monocytes of PCM patients in vitro than healthy controls. Similar intracellular protein expression of NLRP3, CASP-1, ASC, and IL-1ß were also observed in freshly isolated monocytes of PCM patients and smoker controls. Increased expression of NLRP3 and ASC was observed in monocytes from PCM patients under hypoxia in comparison with smoker controls. For the first time, we showed that primed monocytes of CF-PCM patients were associated with enhanced expression of components of NLRP3-inflammasome due to smoke. Also, hypoxemia boosted this machinery. These findings reinforce the systemic low-grade inflammation activation observed in PCM during and after treatment.

Perinatal maternal antibiotic exposure augments lung injury in offspring in experimental bronchopulmonary dysplasia.

During the newborn period, intestinal commensal bacteria influence pulmonary mucosal immunology via the gut-lung axis. Epidemiological studies have linked perinatal antibiotic exposure in human newborns to an increased risk for bronchopulmonary dysplasia, but whether this effect is mediated by the gut-lung axis is unknown. To explore antibiotic disruption of the newborn gut-lung axis, we studied how perinatal maternal antibiotic exposure influenced lung injury in a hyperoxia-based mouse model of bronchopulmonary dysplasia. We report that disruption of intestinal commensal colonization during the perinatal period promotes a more severe bronchopulmonary dysplasia phenotype characterized by increased mortality and pulmonary fibrosis. Mechanistically, metagenomic shifts were associated with decreased IL-22 expression in bronchoalveolar lavage and were independent of hyperoxia-induced inflammasome activation. Collectively, these results demonstrate a previously unrecognized influence of the gut-lung axis during the development of neonatal lung injury, which could be leveraged to ameliorate the most severe and persistent pulmonary complication of preterm birth.

Peroxisome Proliferator-activated Receptor-γ Deficiency Exacerbates Fibrotic Response to Mycobacteria Peptide in Murine Sarcoidosis Model.

We established a murine model of multiwall carbon nanotube (MWCNT)-elicited chronic granulomatous disease that bears similarities to human sarcoidosis pathology, including alveolar macrophage deficiency of peroxisome proliferator-activated receptor γ (PPARγ). Because lymphocyte reactivity to mycobacterial antigens has been reported in sarcoidosis, we hypothesized that addition of mycobacterial ESAT-6 (early secreted antigenic target protein 6) to MWCNT might exacerbate pulmonary granulomatous pathology. MWCNTs with or without ESAT-6 peptide 14 were instilled by the oropharyngeal route into macrophage-specific PPARγ-knockout (KO) or wild-type mice. Control animals received PBS or ESAT-6. Lung tissues, BAL cells, and BAL fluid were evaluated 60 days after instillation. PPARγ-KO mice receiving MWCNT + ESAT-6 had increased granulomas and significantly elevated fibrosis (trichrome staining) compared with wild-type mice or PPARγ-KO mice that received only MWCNT. Immunostaining of lung tissues revealed elevated fibronectin and Siglec F expression on CD11c+ infiltrating alveolar macrophages in the presence of MWCNT + ESAT-6 compared with MWCNT alone. Analyses of BAL fluid proteins indicated increased levels of transforming growth factor (TGF)-ß and the TGF-ß pathway mediator IL-13 in PPARγ-KO mice that received MWCNT + ESAT-6 compared with wild-type or PPARγ-KO mice that received MWCNT. Similarly, mRNA levels of matrix metalloproteinase 9, another requisite factor for TGF-ß production, was elevated in PPARγ-KO mice by MWCNT + ESAT-6. Analysis of ESAT-6 in lung tissues by mass spectrometry revealed ESAT-6 retention in lung tissues of PPARγ-KO but not wild-type mice. These data indicate that PPARγ deficiency promotes pulmonary ESAT-6 retention, exacerbates macrophage responses to MWCNT + ESAT-6, and intensifies pulmonary fibrosis. The present findings suggest that the model may facilitate understanding of the effects of environmental factors on sarcoidosis-associated pulmonary fibrosis.

Promising New Antifungal Treatment Targeting Chorismate Synthase from Paracoccidioides brasiliensis.

Paracoccidioidomycosis (PCM), caused by Paracoccidioides, is a systemic mycosis with granulomatous character and a restricted therapeutic arsenal. The aim of this work was to search for new alternatives to treat largely neglected tropical mycosis, such as PCM. In this context, the enzymes of the shikimate pathway constitute excellent drug targets for conferring selective toxicity because this pathway is absent in humans but essential for the fungus. In this work, we have used a homology model of the chorismate synthase (EC 4.2.3.5) from Paracoccidioides brasiliensis (PbCS) and performed a combination of virtual screening and molecular dynamics testing to identify new potential inhibitors. The best hit, CP1, successfully adhered to pharmacological criteria (adsorption, distribution, metabolism, excretion, and toxicity) and was therefore used in in vitro experiments. Here we demonstrate that CP1 binds with a dissociation constant of 64 ± 1 µM to recombinant chorismate synthase from P. brasiliensis and inhibits enzymatic activity, with a 50% inhibitory concentration (IC50) of 47 ± 5 µM. As expected, CP1 showed no toxicity in three cell lines. On the other hand, CP1 reduced the fungal burden in lungs from treated mice, similar to itraconazole. In addition, histopathological analysis showed that animals treated with CP1 displayed less lung tissue infiltration, fewer yeast cells, and large areas with preserved architecture. Therefore, CP1 was able to control PCM in mice with a lower inflammatory response and is thus a promising candidate and lead structure for the development of drugs useful in PCM treatment.

Polydatin suppresses the development of lung inflammation and fibrosis by inhibiting activation of the NACHT domain-, leucine-rich repeat-, and pyd-containing protein 3 inflammasome and the nuclear factor-κB pathway after Mycoplasma pneumoniae infection.

Mycoplasma pneumoniae (MP) can infect both the upper and lower respiratory tracts. Polydatin (PD), a traditional Chinese medicine, is known to have anti-inflammation and antifibrosis properties. However, the protective effects of PD against MP pneumonia (MPP) remain unclear. So, the aim of this study was to describe the therapeutic effects and underlying mechanisms of PD against MPP. BALB/c mice were assigned to three groups: a normal control group, MP infection group, or PD-treated MP infection group. BEAS-2B cells transfected with or without NACHT domain-, leucine-rich repeat-, and pyd-containing protein 3 (NLRP3) were used to confirm the protective mechanisms of PD. Immunohistochemical analysis, Western blot analysis, enzyme-linked immunosorbent assay, and flow cytometry were used in this study. The results showed that PD treatment suppressed MP-induced lung injury in mice by suppressing the expression of inflammatory factors and inhibiting the development of pulmonary fibrosis. Meanwhile, PD treatment inhibited activation of the NLRP3 inflammasome and nuclear factor κB (NF-κB) pathway. Overexpression of NLRP3 reversed the protective effect of PD against MP-induced injury of BEAS-2B cells. Taken together, these results indicate that PD treatment suppressed the inflammatory response and the development of pulmonary fibrosis by inhibiting the NLRP3 inflammasome and NF-κB pathway after MP infection.

Developing selective media for quantification of multispecies biofilms following antibiotic treatment.

The lungs of cystic fibrosis (CF) patients are chronically colonized by a polymicrobial biofilm community, leading to difficult-to-treat infections. To combat these infections, CF patients are commonly treated with a variety of antibiotics. Understanding the dynamics of polymicrobial community composition in response to antibiotic therapy is essential in the search for novel therapies. Culture-dependent quantification of individual bacteria from defined multispecies biofilms is frequently carried out by plating on selective media. However, the influence of the selective agents in these media on quantitative recovery before or after antibiotic treatment is often unknown. In the present study we developed selective media for six bacterial species that are frequently co-isolated from the CF lung, i.e. Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus anginosus, Achromobacter xylosoxidans, Rothia mucilaginosa, and Gemella haemolysans. We show that certain supplementations to selective media strongly influence quantitative recovery of (un)treated biofilms. Hence, the developed media were optimized for selectivity and quantitative recovery before or after treatment with antibiotics of four major classes, i.e. ceftazidime, ciprofloxacin, colistin, or tobramycin. Finally, in a proof of concept experiment the novel selective media were applied to determine the community composition of multispecies biofilms before and after treatment with tobramycin.

Mortality among patients with pulmonary non-tuberculous mycobacteria disease.

SETTING: Tertiary referral center, National Institutes of Health (NIH), USA. OBJECTIVE: To estimate the mortality rate and its correlates among persons with pulmonary non-tuberculous mycobacteria (PNTM) disease. DESIGN: A retrospective review of 106 patients who were treated at the NIH Clinical Center and met American Thoracic Society/Infectious Diseases Society of America criteria for PNTM. Eligible patients were aged ⩾18 years and did not have cystic fibrosis or human immunodeficiency virus (HIV) infection. RESULTS: Of 106 patients followed for a median of 4.9 years, 27 (25%) died during follow-up, for a mortality rate of 4.2 per 100 person-years. The population was predominantly female (88%) and White (88%), with infrequent comorbidities. Fibrocavitary disease (adjusted hazard ratio [aHR] 3.3, 95% confidence interval [CI] 1.3-8.3) and pulmonary hypertension (aHR 2.1, 95%CI 0.9-5.1) were associated with a significantly elevated risk of mortality in survival analysis. CONCLUSIONS: PNTM remains a serious public health concern, with a consistently elevated mortality rate across multiple populations. Significant risk factors for death include fibrocavitary disease and pulmonary hypertension. Further research is needed to more specifically identify clinical and microbiologic factors that jointly influence disease outcome.

Development of chronic pulmonary aspergillosis in adult asthmatics with ABPA.

BACKGROUND: Chronic pulmonary aspergillosis (CPA) is an occasional complication of allergic bronchopulmonaryaspergillosis (ABPA) but the transition is poorly understood. METHODS: All patients referred to the UK's National Aspergillosis Centre with CPA between May 2009 and June 2012 were screened with serum total IgE and anti-Aspergillus IgE for a dual diagnosis of ABPA and CPA. Those patients suspected of having both conditions were re-evaluated and their imaging reviewed. RESULTS: Of 407 referred patients, 42 screened positive and 22 were confirmed as having both ABPA and CPA. Asthma was present from early childhood in 19 (86%), the median interval between ABPA and onset of CPA was 7.5 years; one patient developed ABPA and CPA simultaneously. Aspergillus IgG levels varied from 23 to 771 mg/L, median 82 mg/L. All 22 patients had bronchiectasis. In patients with ABPA, CT typically demonstrated varicose or cystic bronchiectasis primarily affecting segmental and proximal subsegmental upper lobe bronchi. Other findings included mucoid impaction and centrilobular nodules. Radiological changes associated with CPA included pleural thickening which was often bilateral and accentuated by adjacent hypertrophied extrapleural fat, upper lobe volume loss, thick walled apical cavities, some of which contained aspergillomas, and cavitating pulmonary nodules. CPA secondary to ABPA has more subtle radiological appearances than when due to other underlying diseases. CONCLUSIONS: CPA may complicate ABPA and have distinct radiology features, in addition to bronchiectasis. A novel biomarker is required to anticipate this serious complication, as current serology is not specific enough.

Streptococcus pneumoniae triggers progression of pulmonary fibrosis through pneumolysin.

RATIONALE: Respiratory tract infections are common in patients suffering from pulmonary fibrosis. The interplay between bacterial infection and fibrosis is characterised poorly. OBJECTIVES: To assess the effect of Gram-positive bacterial infection on fibrosis exacerbation in mice. METHODS: Fibrosis progression in response to Streptococcus pneumoniae was examined in two different mouse models of pulmonary fibrosis. MEASUREMENTS AND MAIN RESULTS: We demonstrate that wild-type mice exposed to adenoviral vector delivery of active transforming growth factor-ß1 (TGFß1) or diphteria toxin (DT) treatment of transgenic mice expressing the DT receptor (DTR) under control of the surfactant protein C (SPC) promoter (SPC-DTR) to induce pulmonary fibrosis developed progressive fibrosis following infection with Spn, without exhibiting impaired lung protective immunity against Spn. Antibiotic treatment abolished infection-induced fibrosis progression. The cytotoxin pneumolysin (Ply) of Spn caused this phenomenon in a TLR4-independent manner, as Spn lacking Ply (SpnΔply) failed to trigger progressive fibrogenesis, whereas purified recombinant Ply did. Progressive fibrogenesis was also observed in AdTGFß1-exposed Ply-challenged TLR4 KO mice. Increased apoptotic cell death of alveolar epithelial cells along with an attenuated intrapulmonary release of antifibrogenic prostaglandin E2 was found to underlie progressive fibrogenesis in Ply-challenged AdTGFß1-exposed mice. Importantly, vaccination of mice with the non-cytotoxic Ply derivative B (PdB) substantially attenuated Ply-induced progression of lung fibrosis in AdTGFß1-exposed mice. CONCLUSIONS: Our data unravel a novel mechanism by which infection with Spn through Ply release induces progression of established lung fibrosis, which can be attenuated by protein-based vaccination of mice.

Immunization with recombinant Pb27 protein reduces the levels of pulmonary fibrosis caused by the inflammatory response against Paracoccidioides brasiliensis.

Paracoccidioidomycosis (PCM) is a systemic mycosis in which the host response to the infectious agent typically consists of a chronic granulomatous inflammatory process. This condition causes lesions that impair lung function and lead to chronic pulmonary insufficiency resulting from fibrosis development, which is a sequel and disabling feature of the disease. The rPb27 protein has been studied for prophylactic and therapeutic treatment against PCM. Previous studies from our laboratory have shown a protective effect of rPb27 against PCM. However, these studies have not determined whether rPb27 immunization prevents lung fibrosis. We therefore conducted this study to investigate fibrosis resulting from infection by Paracoccidioides brasiliensis in the lungs of animals immunized with rPb27. Animals were immunized with rPb27 and subsequently infected with a virulent strain of P. brasiliensis. Fungal load was evaluated by counting colony-forming units, and Masson's trichrome staining was performed to evaluate fibrosis at 30 and 90 days post-infection. The levels of CCR7, active caspase 3, collagen and cytokines were analyzed. At the two time intervals mentioned, the rPb27 group showed lower levels of fibrosis on histology and reduced levels of collagen and the chemokine receptor CCR7 in the lungs. CCR7 was detected at higher levels in the control groups that developed very high levels of pulmonary fibrosis. Additionally, the immunized groups showed high levels of active caspase 3, IFN-γ, TGF-ß and IL-10 in the early phase of P. brasiliensis infection. Immunization with Pb27, in addition to its protective effect, was shown to prevent pulmonary fibrosis.

γ-Herpes virus-68, but not Pseudomonas aeruginosa or influenza A (H1N1), exacerbates established murine lung fibrosis.

Patients with idiopathic pulmonary fibrosis (IPF) often do worse following infection, but the cause of the decline is not fully understood. We previously demonstrated that infection with a murine gamma herpes virus (γHV-68) could exacerbate established lung fibrosis following administration of fluorescein isothiocyanate (McMillan et al. Am J Respir Crit Care Med 177: 771-780, 2008). In the present study, we anesthetized mice and injected saline or bleomycin intratracheally on day 0. On day 14, mice were anesthetized again and infected with either a Gram-negative bacteria (Pseudomonas aeruginosa), or with H1N1 or γHV-68 viruses. Measurements were then made on days 15, 21, or 35. We demonstrate that infection with P. aeruginosa does not exacerbate extracellular matrix deposition post-bleomycin. Furthermore, fibrotic mice are effectively able to clear P. aeruginosa infection. In contrast, bleomycin-treated mice develop worse lung fibrosis when infected with γHV-68, but not when infected with H1N1. The differential ability of γHV-68 to cause increased collagen deposition could not be explained by differences in inflammatory cell recruitment or whole lung chemokine and cytokine responses. Alveolar epithelial cells from γHV-68-infected mice displayed increased expression of TGFß receptor 1, increased SMAD3 phosphorylation, and evidence of apoptosis measured by cleaved poly-ADP ribose polymerase (PARP). The ability of γHV-68 to augment fibrosis required the ability of the virus to reactivate from latency. This property appears unique to γHV-68, as the ß-herpes virus, cytomegalovirus, did not have the same effect.

Fibrogenesis in granulomas and lung interstitium in tuberculous inflammation in mice.

The study in mouse model of BCG-induced granulomatous inflammation showed that early pulmonary fibrosis (day 3-30 postinfection) in tuberculous inflammation was primarily determined by increased number of fibroblasts in the lung interstitium and granulomas and enhanced fibroplastic activity. Fibroplastic processes are initiated via an increase in secretory activity of activated granuloma macrophages caused by the persistence of the pathogen in the cells of the mononuclear phagocytic system. The dynamics of hydroxyproline concentration under these conditions is determined by changes in the number and differentiation degree of fibroblasts in granulomas and lung interstitium at various stages of tuberculous inflammation.

Spontaneous latency in a rabbit model of pulmonary tuberculosis.

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is an exquisitely adapted human pathogen capable of surviving for decades in the lungs of immune-competent individuals in the absence of disease. The World Health Organization estimates that 2 billion people have latent TB infection (LTBI), defined by a positive immunological response to Mtb antigens, with no clinical signs of disease. A better understanding of host and pathogen determinants of LTBI and subsequent reactivation would benefit TB control efforts. Animal models of LTBI have been hampered generally by an inability to achieve complete bacillary clearance. Herein, we have characterized a rabbit model of LTBI in which, similar to most humans, complete clearance of pulmonary Mtb infection and pathological characteristics occurs spontaneously. The evidence that Mtb-CDC1551-infected rabbits achieve LTBI, rather than sterilization, is based on the ability of the bacilli to be reactivated after immune suppression. These rabbits showed early activation of T cells and macrophages and an early peak in the TNFα level, which decreased in association with clearance of bacilli from the lungs. In the absence of sustained tumor necrosis factor-α production, no necrosis was seen in the evolving lung granulomas. In addition, bacillary control was associated with down-regulation of several metalloprotease genes and an absence of lung fibrosis. This model will be used to characterize molecular markers of protective immunity and reactivation.

Prospective, observational study of voriconazole therapeutic drug monitoring among lung transplant recipients receiving prophylaxis: factors impacting levels of and associations between serum troughs, efficacy, and toxicity.

Voriconazole prophylaxis is common following lung transplantation, but the value of therapeutic drug monitoring is unknown. A prospective, observational study of lung transplant recipients (n = 93) receiving voriconazole prophylaxis was performed. Serum voriconazole troughs (n = 331) were measured by high-pressure liquid chromatography. The median initial and subsequent troughs were 1.91 and 1.46 µg/ml, respectively. The age of the patient directly correlated with initial troughs (P = 0.005). Patients that were ≥ 60 years old and cystic fibrosis patients were significantly more likely to have higher and lower initial troughs, respectively. In 95% (88/93) of patients, ≥ 2 troughs were measured. In 28% (25/88) and 32% (28/88) of these patients, all troughs were ≤ 1.5 µg/ml or >1.5 µg/ml, respectively. Ten percent (10/93) and 27% (25/93) of the patients developed invasive fungal infection (tracheobronchitis) and fungal colonization, respectively. The median troughs at the times of positive and negative fungal cultures were 0.92 and 1.72 µg/ml (P = 0.07). Invasive fungal infections or colonization were more likely with troughs of ≤ 1.5 µg/ml (P = 0.01) and among patients with no trough of >1.5 µg/ml (P = 0.007). Other cutoff troughs correlated less strongly with microbiologic outcomes. Troughs correlated directly with aspartate transferase levels (P = 0.003), but not with other liver enzymes. Voriconazole was discontinued due to suspected toxicity in 27% (25/93) of the patients. The troughs did not differ at the times of suspected drug-induced hepatotoxicity, central nervous system (CNS) toxicity, or nausea/vomiting and in the absence of toxicity. Voriconazole prophylaxis was most effective at troughs of >1.5 µg/ml. A cutoff for toxicity was not identified, but troughs of >4 µg/ml were rare. The data support a target range of >1.5 to 4 µg/ml.

How invasive aspergillosis may have a beneficial effect after single lung transplantation.

We report the case of a 52-year-old female, who received a left single lung transplantation for end-stage smoking-induced emphysema in 1997. During the last 4 years, she experienced a progressive decline in FEV1, which we attributed to the development of bronchiolitis obliterans syndrome, stage 2. In 2007 she experienced an invasive aspergillosis of the native lung upper lobe, which resolved after 3 months of adequate treatment with voriconazole. After resolution of the infection, both FVC (forced vital capacity) and FEV1 became surprisingly better, due to fibrosis of the affected lobe, compatible with infection-induced volume reduction of the native lung.

Torque teno virus DNA titre elevated in idiopathic pulmonary fibrosis with primary lung cancer.

BACKGROUND AND OBJECTIVE: IPF is an independent risk factor for lung cancer, but the mechanism of this association has not fully been elucidated. The role of Torque teno virus (TTV) in respiratory disease is poorly understood, although it has been shown that infection with TTV is associated with the activity and prognosis of IPF. This study aimed to investigate the prevalence and titre of TTV DNA among patients with IPF and lung cancer. METHODS: The presence of TTV DNA was determined by PCR in the sera of patients with both lung cancer and IPF (n = 22), patients with IPF only (n = 35), and patients with lung cancer only (n = 142). RESULTS: TTV DNA was detectable in all patients with both IPF and lung cancer, in 94.3% of the patients with IPF only and 97.2% of the patients with lung cancer only. The TTV DNA titre in the patients with IPF and lung cancer was significantly higher than that in the patients with IPF only or lung cancer only. The percentage of TTV-positive patients with a high TTV titre in the IPF and lung cancer group was significantly higher than that in the IPF only group. CONCLUSIONS: These findings are the first report on the association between TTV and the complication of lung cancer in IPF and suggest that TTV infection might be associated with the development of lung cancer in IPF.