Lung Parenchymal Tissue Research Articles

Expression of miR-150 and miR-3940-5p is reduced in non-small cell lung carcinoma and correlates with clinicopathological features

The present study investigated the expression of miR-150 and miR-3940-5p in non-small cell lung carcinoma(NSCLC) and its relationship with clinicopathologic features. Samples included tumor, tumor-adjacent and normal lung parenchyma tissues from 90 NSCLC patients and 17 cases of embryonic lung cDNA. The expression levels of miR-150, miR-18b-5p, miR-643 and miR-3940-5p were detected by real‑time PCR; p53, EGFR, Kras and Ki-67 expression in tumor tissues was determined by immunohistochemistry. p53 mRNA expression levels in NSCLC were examined by SYBR-Green real-time PCR. The relationship between the four miRNAs and clinicopathologic features of 90 cases was analyzed. The expression of miR-150 and miR-3940-5p was significantly downregulated in tumor tissues and embryonic lung tissues compared to normal lung tissues. The expression of miR-150 and miR-3940-5p in tumor tissues was also lower than that in the matched tumor-adjacent tissues. miR-150 was downregulated preferentially in subgroups of patients with a tumor diameter more than or equal to 3cm, in smokers and in stageIII and IV tumors. Specifically, miR-150 and miR-3940-5p expression was decreased in nuclear cell proliferation antigen Ki-67-positive NSCLC cases. miR-150 and miR-3940-5p were found to be significantly downregulated in p53 IHC-positive NSCLC cases and were negatively correlated with p53 mRNA. Reduced miR-150 and miR-3940-5p expression in tumor tissues and embryonic lung tissues suggests that these miRs may be involved in the tumorigenesis or de-differentiation of NSCLC. Due to this associaton with the Ki-67 proliferation index in NSCLC, downregulation of miR-150 and miR-3940-5p may contribute to tumor growth and proliferation. miR-150 and miR-3940-5p may affect p53 expression through a direct or indirect pathway.

Sex-Specific Perinatal Nicotine-Induced Asthma in Rat Offspring

Recently, we have suggested that down-regulation of homeostatic mesenchymal peroxisome proliferator-activated receptor γ signaling after in utero nicotine exposure might contribute to asthma. Here, we have exploited an in vivo rat model of asthma to determine if the effects of perinatal nicotine exposure on offspring pulmonary function and mesenchymal markers of airway contractility in both tracheal and lung parenchymal tissue are sex specific, and whether the protection afforded by the peroxisome proliferator-activated receptor γ agonist, rosiglitazone (RGZ), against the perinatal nicotine-induced effect on offspring lung is also sex specific. Pregnant rat dams received placebo, nicotine, or nicotine plus RGZ daily from Embryonic Day 6 until Postnatal Day 21, at which time lung resistance, compliance, tracheal contractility, and the expression of structural and functional mesenchymal markers of pulmonary contractility were determined. Compared with control animals, perinatal nicotine exposure caused a significant increase in airway resistance and a decrease in airway compliance after a methacholine challenge in both male and female offspring, with more pronounced changes in the males. In contrast to this, the effects of perinatal nicotine exposure on acetylcholine-induced tracheal constriction, along with the expression of its mesenchymal markers, were observed exclusively in the male offspring. Concomitant treatment with RGZ normalized the nicotine-induced alterations in pulmonary function in both sexes, as well as the male-specific effects on acetylcholine-induced tracheal constriction, along with the affected mesenchymal markers. These data suggest that perinatal nicotine exposure causes sex-specific perinatal cigarette smoke exposure-induced asthma, providing a powerful phenotypic model for unequivocally determining the underlying nature of the cell molecular mechanism for this disease.

Patients with cystic fibrosis have inducible IL-17+IL-22+ memory cells in lung draining lymph nodes

IL-17 is an important cytokine signature of the TH differentiation pathway TH17. This T-cell subset is crucial in mediating autoimmune disease or antimicrobial immunity in animal models, but its presence and role in human disease remain to be completely characterized. We set out to determine the frequency of TH17 cells in patients with cystic fibrosis (CF), a disease in which there is recurrent infection with known pathogens. Explanted lungs from patients undergoing transplantation or organ donors (CF samples=18; non-CF, nonbronchiectatic samples=10) were collected. Hilar nodes and parenchymal lung tissue were processed and examined for TH17 signature by using immunofluorescence and quantitative real-time PCR. T cells were isolated and stimulated with antigens from Pseudomonas aeruginosa and Aspergillus species. Cytokine profiles and staining with flow cytometry were used to assess the reactivity of these cells to antigen stimulation. We found a strong IL-17 phenotype in patients with CF compared with that seen in control subjects without CF. Within this tissue, we found pathogenic antigen-responsive CD4+IL-17+ cells. There were double-positive IL-17+IL-22+ cells [TH17(22)], and the IL-22+ population had a higher proportion of memory characteristics. Antigen-specific TH17 responses were stronger in the draining lymph nodes compared with those seen in matched parenchymal lungs. Inducible proliferation of TH17(22) with memory cell characteristics is seen in the lungs of patients with CF. The function of these individual subpopulations will require further study regarding their development. T cells are likely not the exclusive producers of IL-17 and IL-22, and this will require further characterization.

Progression of small, irregular opacities in chest radiographs of former asbestos workers

Pulmonary parenchymal changes appear many years after the start of exposure to asbestos and their progression has been observed to continue many years after cessation of the exposure. The aim of the present analysis is to assess the risk of progression of radiological changes in the respiratory system, based on long-term follow-up of groups of workers occupationally exposed to asbestos dust. The analysis included 3144 individuals voluntarily applying for a medical examination in 2000-2010, who had performed at least two radiographs of the chest. Probability of progression in subsequent studies was based on the evaluation of radiographs for the presence of small, irregular type s, t, u opacities in the parenchymal lung tissue with profusion categories as specified in the classification of ILO, 1980. Multistate hidden Markov model was used in the statistical analysis. In the group of patients, small irregular opacities with a profusion of 1/1 or higher occurred in 640 (20%) patients in the first examination, and in 918 (29%) patients in the last examination. No parenchymal changes were observed in 1360 (43%) patients in the first examination (opacity profusion category 0/0), and in 645 (20%) patients in the last examination. The risk of progression of radiographic changes in former workers of asbestos processing plants is higher in smokers, from profusion category 0 to 1 - by 30% (HR = 1.30, 95% CI: 1.15-1.47), from profusion category 1 to 2 - by 50% (HR = 1.50, 95% CI: 0.92-2.45). The risk of progression of parenchymal changes decreases in the workers employed in subsequent calendar years: for category changes from 1 to 2, the decrease is nearly 40% for every 10 years of subsequent employment (HR = 0.60, 95% CI: 0.45-0.80). The probability of the progression increases with longer latency period: for change of category from 1 to 2, the increase is about 20% (HR = 1.19, 95% CI: 1.00-1.42) per 10 years of employment for blue collar workers. The risk of the 1 to 2 category progression is significant, nearly 2.5-fold higher in the workers employed in the asbestos-processing textile industry. Our results show that the risk of progression of pulmonary parenchymal fibrotic processes was higher in the smokers, workers employed during the earlier calendar years of the discussed period, those with longer latency period, blue collar workers involved directly in the production processes, and employees of the asbestos cement and/or textile industries.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

Dendritic cell depletion and repopulation in the lung after irradiation and bone marrow transplantation in mice

Macrophages and dendritic cells are essential for innate and adaptive immunity, respectively and have been reported to exhibit variable radiosensitivities in response to irradiation in various bone marrow transplantation (BMT) protocols. In order to address this controversy, we analyzed the magnitude of depletion and repopulation of both “conventional“ CD11bpos DC and CD103pos DC subsets as well as different pulmonary macrophage subsets in the lung tissue in response to irradiation and BMT in a mouse model. In our study, CD45.2pos donor bone marrow cells were transplanted into irradiated CD45.1pos recipient mice, in order to examine the depletion of recipient-type and the repopulation of donor-type DC and macrophage subsets. We observed an apoptosis- and necrosis-mediated &gt;90% depletion of the recipient CD103pos DC subset and only a 50–60% depletion of recipient CD11bpos DC from lung parenchymal tissue at day 3 and 5, whereas recipient alveolar and lung macrophages were much less radiosensitive, showing ˜50% depletion by days 14–21 post-treatment. Complete repopulation of lung tissue with donor DC subsets was observed by days 10 and 28 for CD11bpos DC and CD103pos DC, whereas alveolar and lung macrophages were repopulated by 6 and 10 weeks post-treatment. Furthermore, infection of mice with S. pneumoniae highly accelerated the turnover of lung DC as well as lung macrophage subsets. Our data illustrate the vulnerability of lung CD103pos DC and CD11bpos DC to irradiation and indicate an accelerated turnover of lung DC subsets relative to pulmonary macrophages. Our findings may have important implications for the development of adjuvant immune-stimulatory protocols which could reduce the risk of opportunistic infections in patients undergoing BMT.

Inhaled Nitrite Reverses Hemolysis-Induced Pulmonary Vasoconstriction in Newborn Lambs Without Blood Participation

Nitrite can be converted to nitric oxide (NO) by a number of different biochemical pathways. In newborn lambs, an aerosol of inhaled nitrite has been found to reduce pulmonary blood pressure, possibly acting via conversion to NO by reaction with intraerythrocytic deoxyhemoglobin. If so, the vasodilating effects of nitrite would be attenuated by free hemoglobin in plasma that would rapidly scavenge NO. Pulmonary vascular pressures and resistances to flow were measured in anesthetized newborn lambs. Plasma hemoglobin concentrations were then elevated, resulting in marked pulmonary hypertension. This effect was attenuated if infused hemoglobin was first oxidized to methemoglobin, which does not scavenge NO. These results further implicate NO as a tonic pulmonary vasodilator. Next, while free hemoglobin continued to be infused, the lambs were given inhaled NO gas (20 ppm), inhaled sodium nitrite aerosol (0.87 mol/L), or an intravascular nitrite infusion (3 mg/h bolus, 5 mg · kg⁻¹ · h⁻¹ infusion). Inhaled NO and inhaled nitrite aerosol both resulted in pulmonary vasodilation. Intravascular infusion of nitrite, however, did not. Increases in exhaled NO gas were observed in lambs while breathing the nitrite aerosol (≈ 20 ppb NO) but not during intravascular infusion of nitrite. We conclude that the pulmonary vasodilating effect of inhaled nitrite results from its conversion to NO in airway and parenchymal lung tissue and is not dependent on reactions with deoxyhemoglobin in the pulmonary circulation. Inhaled nitrite aerosol remains a promising candidate to reduce pulmonary hypertension in clinical application.

Lung tissue mechanics as an emergent phenomenon

The mechanical properties of lung parenchymal tissue are both elastic and dissipative, as well as being highly nonlinear. These properties cannot be fully understood, however, in terms of the individual constituents of the tissue. Rather, the mechanical behavior of lung tissue emerges as a macroscopic phenomenon from the interactions of its microscopic components in a way that is neither intuitive nor easily understood. In this review, we first consider the quasi-static mechanical behavior of lung tissue and discuss computational models that show how smooth nonlinear stress-strain behavior can arise through a percolation-like process in which the sequential recruitment of collagen fibers with increasing strain causes them to progressively take over the load-bearing role from elastin. We also show how the concept of percolation can be used to link the pathologic progression of parenchymal disease at the micro scale to physiological symptoms at the macro scale. We then examine the dynamic mechanical behavior of lung tissue, which invokes the notion of tissue resistance. Although usually modeled phenomenologically in terms of collections of springs and dashpots, lung tissue viscoelasticity again can be seen to reflect various types of complex dynamic interactions at the molecular level. Finally, we discuss the inevitability of why lung tissue mechanics need to be complex.

Dendritic Cell Depletion and Repopulation in the Lung after Irradiation and Bone Marrow Transplantation in Mice

Dendritic cells (DCs) are essential for innate and adaptive immunity, but are purported to exhibit variable radiosensitivity in response to irradiation in various bone marrow transplantation (BMT) protocols. To address this controversy, we analyzed the magnitude of depletion and repopulation of both lung CD11b(pos) DC and CD103(pos) DC subsets in response to irradiation and BMT in a murine model. In our study, CD45.2(pos) donor bone marrow cells were transplanted into irradiated CD45.1(pos) recipient mice to examine the depletion of recipient DC subsets and the repopulation of donor DC subsets. We observed an apoptosis-mediated and necrosis-mediated depletion (> 90%) of the recipient CD103(pos) DC subset, and only a 50-60% depletion of recipient CD11b(pos) DCs from lung parenchymal tissue on Days 3 and 5, whereas recipient alveolar and lung macrophages were much less radiosensitive, showing an approximately 50% depletion by Days 14-21 after treatment. A repopulation of lung tissue with donor DC subsets had occurred by Days 10 and 28 for CD11b(pos) DCs and CD103(pos) DCs, whereas alveolar and lung macrophages were repopulated by 6 and 10 weeks after treatment. Furthermore, the infection of mice with Streptococcus pneumoniae further accelerated the turnover of lung DCs and lung macrophage subsets. Our data illustrate the vulnerability of lung CD103(pos) DCs and CD11b(pos) DCs to irradiation, and indicate that an accelerated turnover of lung DC subsets occurs, relative to pulmonary and lung macrophages. Our findings may have important implications in the development of adjuvant immune-stimulatory protocols that could reduce the risk of opportunistic infections in patients undergoing BMT.

Oxidative modification of albumin in the parenchymal lung tissue of current smokers with chronic obstructive pulmonary disease

BackgroundThere is accumulating evidence that oxidative stress plays an important role in the pathophysiology of chronic obstructive pulmonary disease (COPD). One current hypothesis is that the increased oxidant burden in these patients is not adequately counterbalanced by the lung antioxidant systems.ObjectiveTo determine the levels of oxidised human serum albumin (HSA) in COPD lung explants and the effect of oxidation on HSA degradation using an ex vivo lung explant model.MethodsParenchymal lung tissue was obtained from 38 patients (15F/23M) undergoing lung resection and stratified by smoking history and disease using the GOLD guidelines and the lower limit of normal for FEV1/FVC ratio. Lung tissue was homogenised and analysed by ELISA for total levels of HSA and carbonylated HSA. To determine oxidised HSA degradation lung tissue explants were incubated with either 200 μg/ml HSA or oxidised HSA and supernatants collected at 1, 2, 4, 6, and 24 h and analysed for HSA using ELISA and immunoblot.ResultsWhen stratified by disease, lung tissue from GOLD II (median = 38.2 μg/ml) and GOLD I (median = 48.4 μg/ml) patients had lower levels of HSA compared to patients with normal lung function (median = 71.9 μg/ml, P < 0.05). In addition the number of carbonyl residues, which is a measure of oxidation was elevated in GOLD I and II tissue compared to individuals with normal lung function (P < 0.05). When analysing smoking status current smokers had lower levels of HSA (median = 43.3 μg/ml, P < 0.05) compared to ex smokers (median = 71.9 μg/ml) and non-smokers (median = 71.2 μg/ml) and significantly greater number of carbonyl residues per HSA molecule (P < 0.05). When incubated with either HSA or oxidised HSA lung tissue explants rapidly degraded the oxidised HSA but not unmodified HSA (P < 0.05).ConclusionWe report on a reliable methodology for measuring levels of oxidised HSA in human lung tissue and cell culture supernatant. We propose that differences in the levels of oxidised HSA within lung tissue from COPD patients and current smokers provides further evidence for an oxidant/antioxidant imbalance and has important biological implications for the disease.

A Microdosimetric Reassessment of New Data on the Effects of Plutonium Dioxide Inhalation by Beagle Dogs

Traditionally, the assessment of the effects of radiation on living tissue has been made in terms of absorbed dose. This concept, however, might not be the most appropriate when considering the effects arising from the inhalation of insoluble radioactive particulates in inhomogeneous tissue such as the lung. We have therefore applied microdosimetric methods to this problem and, in particular, investigated in detail how energy depositions are distributed when alpha particles travel through parenchymal lung tissue. Sections of material derived from rat, beagle and human lung were examined in an image analyzer, and an imaginary plutonium dioxide particulate was placed on the surface of an alveolar sac. The hypothetical alpha particles emitted from it were followed to the ends of their tracks so that the effects of the material's real structure could be followed in detail. It was found that, taking such detail into account, the alpha particles traveled much greater distances than might have been thought on the basis of a uniform, structureless lung. It was also found that the specific energy distributions can cover several orders of magnitude and can differ significantly between tissue as a whole, cells and nuclei at low exposures. Attempts are made to correlate these results with recently published data on beagle dogs that had inhaled graded exposure levels of plutonium dioxide aerosols.

Effect of enkephalinase inhibitor on endothelin-1 induced bronchoconstriction in guinea pigs

Endothelin-1 (ET-1) is one of the most potent bronchoconstrictors in the guinea pig. The mechanism of its metabolism is still unclear. Phosphoramidon is known to be an enkephalinase inhibitor. We studied the effect of phosphoramidon on bronchoconstriction induced by ET-1. In the first in vitro study, a tracheal preparation was mounted in oxygenated Krebs-Ringer solution. The response was monitored by isometric transducer. Dose-response curves to ET-1 with or without phosphoramidon were obtained. Phosphoramidon potentiated ET-1 induced bronchoconstriction significantly. Next, the specific airway conductance (sGaw) was measured in conscious guinea pigs exposed to an aerosol of phosphoramidon or saline, followed by ET-1 aerosol inhalation. The ET-1 dose was increased by successively doubling the concentration. sGaw, after inhalation of phosphoramidon, was significantly reduced when exposed to ET-1. Phosphoramidon also potentiated ET-1 induced bronchoconstriction in vivo. Next, lung parenchymal tissues were prepared and placed in oxygenated Krebs-Ringer solution with or without phosphoramidon. ET-1 was added and incubated, and samples were injected into a high performance liquid chromatography column. Phosphoramidon inhibited an analysis of ET-1. These data suggest that enkephalinase plays a role in the break down of ET-1 in the airway of the guinea pig. Under the condition of decreased enkephalinase, ET-1 would potentiate bronchoconstriction.

Clinical report on a computer-controlled hand-actuated stapling system for general lung surgery: the first application in Japan

Computer-controlled stapling systems can improve lung tissue approximation during thoracic surgery. We report our experience with a handy system with computer-controlled placement of staples for lung resection in Japan. The iDrive system is the improved second version of the SurgAssist stapling system. It comprises a self-contained computer microprocessor and hand-held control unit combined with a digital loading unit (a power linear cutter with a blue or green cartridge) for use in open and minimally invasive thoracic surgery. The mounted control unit has two uses: (1) controlling accurate placement of the cartridge by orientating the tip of the rigid and curved shaft and (2) controlling the closure of the stapler and the firing. Each cartridge contains a programmed electronic device that triggers activation of the appropriate program in the self-contained microprocessor. The compression level on lung tissue is determined by the computer. From March to October 2008, the iDrive system was used 53 times in a consecutive series of 39 patients during open thoracic lung surgery. There were 12 women and 27 men. The following procedures were performed: lobectomy, segmentectomy, and wedge resection. The power linear cutters were used for stapling lung parenchyma for wedge resection in 6 patients, bullectomy in 1, segmentectomy in 2, and fissure division in 33. There were no stapling failures and no complications related to the staplers. The new computer-controlled stapling system may be safe and efficient for lung parenchymal tissue resection during open thoracic surgery.

Stereological study of the effects of Doxycycline on hyperoxic lung injury In neonatal rats

Objective To explore the influence and potential protective effects of non-specific panMetrix Metalloproteinases(MMPs) inhibitor Doxycycline on hyperoxic lung injury and lung development in neonatal rats.Methods Neonatal SD rats were divided into 4 groups randomly within 12 hours after birth:air with normal saline(AN),air with doxycycline(AD),hyperoxia with normal saline(ON),and hyperoxia with doxycycline group(OD).Hyperoxia groups(ON and OD) were exposed to ≥90% O2.Doxycycline 20 mg/kg or equal volume of 0.9% saline(Doxycycline concentration 2 mg/ml) was administered by gastric gavage,twice daily from day 1 to experimental day,but it didn't exceed 14 days.Stereological study was carried out at day 1,3,7,14 and 21 after birth.Results Enlarged mean alveolar area was noted both in hyperoxia and Doxycycline groups.OD group had larger star volume than ON group on day 14.Except ON group,all other groups had increased alveolar septum and the condition was worsened by hyperoxia with Doxycycline.The percentage of collagen in lung parenchymal tissue in ON group increased persistently.This increasing trend was stopped in OD group on day 14,and collagen percentage had no significantly difference between OD and AN groups on day 14 and 21.Conclusion Both hyperoxia and Doxycycline influence neonatal lung development,percentage of coUgen in lung parenchymai can be reduced by Doxycycline in hyperoxic lung injury. Key words: Rats,neonatal; Lung injury; Stereology; Hyperoxia; Doxycycline

Lung Parenchymal Tissue Stiffness in Fibrosis and Cellular Responses to Substrate Stiffness

Stiffening of the lung parenchyma is one of the cardinal features of progressive pulmonary fibrosis, giving rise to a heterogeneous microenvironment with continuous gradients in stiffness. To define the local mechanical environment of the lung fibroblast, we directly measured the local elastic modulus and elasticity gradients of tissue strips from bleomycin treated mouse lung at the cellular scale using AFM force mapping technique. Elastographs revealed a heterogeneous spatial distribution of tissue stiffness with shear moduli ranging from 0.01 to 20 kPa in both normal and fibrotic lung. Fibrotic lung presented incremental stiffness and spatial heterogeneity. The median shear modulus shifted from 0.1 kPa in normal lung to 3 kPa in fibrotic lung. We then prepared a model system using 2D collagen-coated polyacrylamide substrates with stiffness gradients ranging from 0.1 to 50 kPa to study the role that local stiffness play in focusing fibroblast growth and activation. Human lung fibroblasts growing on stiffness gradients exhibited increased spatial density as substrate stiffness increased, suggesting that proliferation and/or migration responses on stiffness bias fibroblast accumulation to the stiffest region. Immunostaining indicated that stiffness increases focal adhesion size, alpha-smooth muscle actin expression, procollagen I expression, as well as the fibrogenic effect of TGF-beta1 on lung fibroblast. Together these results demonstrate that fibroblast accumulation and activation are biased to areas of increased substrate stiffness, and more importantly, that regional mechanical factors could underpin fibrotic progression in the lung through positive feedback loops of fibroblast recruitment and activation.

Intralobar sequestration of lung

Intralobar pulmonary sequestration is characterized by the presence of nonfunctional parenchymal lung tissue, receiving systemic arterial blood supply. It lacks normal communication with tracheobronchial tree. Failure to diagnose and treat this condition can lead to recurrent pneumonia and fatal hemoptysis. The aim of this case report is to increase awareness about the condition and to review criteria of its definitive diagnosis and subsequent treatment.

Mice That Overexpress CC Chemokine Ligand 2 in Their Lungs Show Increased Protective Immunity to Infection withMycobacterium bovisBacille Calmette‐Guérin

The acute phase of mycobacterial lung infection is characterized by a nearly exponential outgrowth of mycobacteria in the alveolar airspace and lung parenchymal tissue, suggesting insufficient early protective immunity against mycobacterial challenge. In the current study, we tested the hypothesis that a CC chemokine ligand 2 (CCL2)-dependent increased mononuclear phagocyte subset accumulation in distal airspaces would improve the lungs' protective immunity to infection with Mycobacterium bovis bacille Calmette-Guérin (hereafter, "M. bovis BCG"). Wild-type mice and CCL2-overexpressing mice that exhibited increased pools of alveolar and lung mononuclear phagocytes-due to the lung-specific overexpression of human CCL2 in type-II alveolar epithelial cells-were infected intratracheally with M. bovis BCG and the developing lung inflammatory response was analyzed. CCL2-overexpressing mice demonstrated significantly decreased mycobacterial loads in the bronchoalveolar space, lung parenchymal tissue, and spleen compared with wild-type mice, when both groups of mice were infected with M. bovis BCG. Moreover, in M. bovis BCG-infected mice, later-developing, accelerated resolution of lung granuloma formation was noted, particularly in CCL2-overexpressing mice as compared with wild-type mice. In addition, CCL2-overexpressing mice demonstrated an increased trafficking of mycobacteria-loaded dendritic cells towards lung-draining lymph nodes that was found to coincide with increased mycobacterial loads in this compartment. The data of the current study suggest that CCL2-dependent amplification of endogenous host-defense programs in the lung may improve the lungs' protective immunity against mycobacterial infections.

Overexpression of cathepsin K in mice decreases collagen deposition and lung resistance in response to bleomycin-induced pulmonary fibrosis

BackgroundLung fibrosis is a devastating pulmonary disorder characterized by alveolar epithelial injury, extracellular matrix deposition and scar tissue formation. Due to its potent collagenolytic activity, cathepsin K, a lysosomal cysteine protease is an interesting target molecule with therapeutic potential to attenuate bleomycin-induced pulmonary fibrosis in mice. We here tested the hypothesis that over-expression of cathepsin K in the lungs of mice is protective in bleomycin-induced pulmonary fibrosis.MethodsWild-type and cathepsin K overexpressing (cathepsin K transgenic; cath K tg) mice were challenged intratracheally with bleomycin and sacrificed at 1, 2, 3 and 4 weeks post-treatment followed by determination of lung fibrosis by estimating lung collagen content, lung histopathology, leukocytic infiltrates and lung function. In addition, changes in cathepsin K protein levels in the lung were determined by immunohistochemistry, real time RT-PCR and western blotting.ResultsCathepsin K protein levels were strongly increased in alveolar macrophages and lung parenchymal tissue of mock-treated cathepsin K transgenic (cath K tg) mice relative to wild-type mice and further increased particularly in cath K tg but also wild-type mice in response to bleomycin. Moreover, cath K tg mice responded with a lower collagen deposition in their lungs, which was accompanied by a significantly lower lung resistance (RL) compared to bleomycin-treated wild-type mice. In addition, cath K tg mice responded with a lower degree of lung fibrosis than wild-type mice, a process that was found to be independent of inflammatory leukocyte mobilization in response to bleomycin challenge.ConclusionOver-expression of cathepsin K reduced lung collagen deposition and improved lung function parameters in the lungs of transgenic mice, thereby providing at least partial protection against bleomycin-induced lung fibrosis.

MECHANICAL TESTING AND INVERSE ANALYSIS FOR DEVELOPING A MATERIAL MODEL OF LUNG PARENCHYMA

The mechanical ventilation of patients with Acute Respiratory Distress Syndrome (ARDS) and Acute Lung Injury (ALI) is a life saving treatment. However, insufficient understanding of lung mechanics can cause overstraining of the parenchymal tissue resulting in additional inflammatory injuries. These ventilation induced lung injuries (VILI) are mainly occurring in the alveolar tissue. The goal of our research is to improve mechanical ventilation, and thus to reduce the frequency and severity of VILI. Our research focuses on the development of different computational models that should serve a better understanding of the lung [Wiechert, 2007]. We are working on different projects concerning this complex multiscale problem. Since VILI occur mainly in the alveolar tissue, this work concentrates on a better understanding and modeling of this tissue. Our aim is to come up with accurate material models of parenchymal lung tissue. Currently our work is based on two material models for soft biological tissue that are already implemented in our research code [Holzapfel, 2001], [Itskov, 2006]. By mechanically testing tissue slices we will be able to determine appropriate material parameters of alveolar tissue more precisely and use these in our model development.

The utility of a reusable bipolar sealing instrument, BiClamp®, for pulmonary resection

To assess the use of a combination of bipolar sealing and electrosurgical coagulation for pulmonary resection. The procedure was used in both dogs and humans. Initially, lung wedge resections were performed on six healthy, Beagle dogs using a voltage controlled electrosurgical system. The area of lung tissue to be resected was first coagulated to provide a distinct line of seal. The lung was then resected along the peripheral site of the sealing scar. Efficiency of sealing was assessed using a tracheally applied air pressure of 30cmH(2)O. The electro-cauterized tissue was compared histologically to tissue sealed by a standard stapling technique. In the clinical phase, lung resections were performed after cauterization in 17 patients. Bullectomies were performed using video-assisted thoracic surgery in 4 patients, and thoracotomic procedures in 13 (1 bullectomy, 5 wedge resections, and 7 fissure separations). Dogs: Tissue sealing was highly successful, without any air leakage, in all six dogs. Histologically, the clamped lesion showed tissue-fusion probably due to both the compression and thermal effects. The proximal zone adjacent to the clamped lesion revealed both collapsed alveolar spaces and fused alveolar walls. In comparison, the stapled lesions showed no tissue-fusion. Humans: There were no major complications. The median operation time was 189min, and estimated median hemorrhage volume was 67ml. Median chest drainage duration was 3 days (range: 1-7) and no patient suffered from prolonged air leakage (>7 days). Lung parenchymal tissue resection following bipolar sealing and electrosurgical coagulation instead of staples was efficient and simple. Furthermore, the technique reduced the use of staples, reducing the cost of the surgery.