Magnus Dahlbäck

Altered fibroblast proteoglycan production in COPD

BackgroundAirway remodeling in COPD includes reorganization of the extracellular matrix. Proteoglycans play a crucial role in this process as regulators of the integrity of the extracellular matrix. Altered proteoglycan immunostaining has been demonstrated in COPD lungs and this has been suggested to contribute to the pathogenesis. The major cell type responsible for production and maintenance of ECM constituents, such as proteoglycans, are fibroblasts. Interestingly, it has been proposed that central airways and alveolar lung parenchyma contain distinct fibroblast populations. This study explores the hypothesis that altered depositions of proteoglycans in COPD lungs, and in particular versican and perlecan, is a result of dysregulated fibroblast proteoglycan production.MethodsProliferation, proteoglycan production and the response to TGF-β1 were examined in vitro in centrally and distally derived fibroblasts isolated from COPD patients (GOLD stage IV) and from control subjects.ResultsPhenotypically different fibroblast populations were identified in central airways and in the lung parenchyma. Versican production was higher in distal fibroblasts from COPD patients than from control subjects (p < 0.01). In addition, perlecan production was lower in centrally derived fibroblasts from COPD patients than from control subjects (p < 0.01). TGF-β1 triggered similar increases in proteoglycan production in distally derived fibroblasts from COPD patients and control subjects. In contrast, centrally derived fibroblasts from COPD patients were less responsive to TGF-β1 than those from control subjects.ConclusionsThe results show that fibroblasts from COPD patients have alterations in proteoglycan production that may contribute to disease development. Distally derived fibroblasts from COPD patients have enhanced production of versican that may have a negative influence on the elastic recoil. In addition, a lower perlecan production in centrally derived fibroblasts from COPD patients may indicate alterations in bronchial basement membrane integrity in severe COPD.

Direct demonstration of tissue uptake of an inhaled drug: proof-of-principle study using matrix assisted laser desorption ionization mass spectrometry imaging

Drug therapy is often directed to specific organ and tissue compartments where the mode of action of the compound affects specifically targeted biological processes. However, the direct measurement of drug uptake in terms of a time kinetic and concentrations attained at the local sites has not been readily available as a clinical index for most drugs. A proof-of-principle study was conducted to test the utility of applying matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) to demonstrate the qualitative distribution pattern of a locally administered drug within tissue sites of targeted action. Here we have measured the occurrence of an inhaled bronchodilator, the muscarinic receptor antagonist ipratropium, within human bronchial biopsies obtained by fiber optic bronchoscopy shortly after dosing exposure. Cryo-preserved biopsy samples from five subjects being evaluated for airway obstruction or potential tumor development were prepared as thin frozen sections. Samples coated with a MALDI matrix were analyzed by a MALDI LTQ Orbitrap XL mass spectrometer at large (100 μm) and small (30 μm) raster sizes. Our results demonstrate that ipratropium is rapidly absorbed into the airway wall. Ipratropium parent ion (m/z 332.332) and daughter ions (m/z 166.2 and 290.2) were coincidently partitioned within submucosal spaces containing targeted airway smooth muscle in four out of five subjects. The signal intensity of ipratropium fragment ions provided estimates that local drug concentrations between 3 and 80 nM were achieved within the airway wall. To our knowledge, this is the first reported study in applying MALDI-MSI to demonstrate the localization of a drug administered at therapeutic levels. The study highlights the potential benefit of MALDI-MSI to provide important measurements of drug efficacy in clinical settings.

Short-term effect of changes in smoking behaviour on emphysema quantification by CT

Background The effect of smoking cessation and smoking relapse on lung density was studied using low-dose CT. Methods Spiral, multidetector, low-dose CT was performed on 726 current and former smokers (>20 pack-years) recruited from a cancer screening trial. Lung density was quantified by calculating the 15th percentile density (PD15), which was adjusted to predicted total lung capacity. Data were analysed by linear regression models. Results At baseline mean PD15 was 45 g/l in former smokers (n=178) and 55 g/l in current smokers (n=548), representing a difference of 10 g/l (p<0.001). After smoking cessation (n=77) PD15 decreased by 6.2 g/l (p<0.001) in the first year, and by a further 3.6 g/l (p<0.001) in the second year, after which no further change could be detected. Moreover, the first year after relapse to smoking (n=18) PD15 increased by 3.7 g/l (p=0.02). Conclusions Current smoking status has a major influence on lung density assessed by CT, and the difference in lung density between current and former smokers observed in cross-sectional studies corresponds closely to the change in lung density seen in the years after smoking cessation. Current smoking status, and time since cessation or relapse, should be taken into account when assessing the severity of diseases such as emphysema by CT lung density.

Developments in biobanking workflow standardization providing sample integrity and stability

UNLABELLED Recommendations and outlines for standardization in biobanking processes are presented by a research team with long-term experience in clinical studies. These processes have important bearing on the use of samples in developing assays. These measurements are useful to document states of health and disease that are beneficial for academic research, commercial healthcare, drug development industry and government regulating agencies. There is a need for increasing awareness within proteomic and genomic communities regarding the basic concepts of collecting, storing and utilizing clinical samples. Quality control and sample suitability for analysis need to be documented and validated to ensure data integrity and establish contexts for interpretation of results. Standardized methods in proteomics and genomics are required to be practiced throughout the community allowing datasets to be comparable and shared for analysis. For example, sample processing of thousands of clinical samples, performed in 384 high-density sample tube systems in a fully automated workflow, preserves sample content and is presented showing validation criteria. Large studies will be accompanied by biological and molecular information with corresponding clinical records from patients and healthy donors. These developments position biobanks of human patient samples as an increasingly recognized major asset in disease research, future drug development and within patient care. BIOLOGICAL SIGNIFICANCE The current manuscript is of major relevance to the proteomic and genomic fields, as it outlines the standardization aspects of biobanking and the requirements that are needed to run future clinical studies that will benefit the patients where OMICS science will play a major role. A global view of the field is given where best practice and conventional acceptances are presented along with ongoing large-scale biobanking projects. The authors represent broadly stakeholders that cover the academic, pharma, biotech and healthcare fields with extensive experience and deliveries. This contribution will be a milestone paper to the proteomic and genomic scientists to present data in the future that will have impact to the life science area. This article is part of a Special Issue entitled: Standardization and Quality Control in Proteomics.

Passage of aerosolized BSA and the nona-peptide dDAVP via the respiratory tract in young and adult rats

The passage of the protein marker, bovine serum albumin (BSA, MW = 67,000), and the nona-peptide, 1-deaminocysteine-8-D-arginine vasopressin (dDAVP, MW = 1067), from the respiratory tract into the blood when applied as an aerosol with a MMAD of 1.7 microns was studied in 14-, 30-, and 100-120-day-old (adult) healthy rats and in adult rats with lung injury. In blood serum of adult rats the levels of immunoreactive BSA reached its maximum 16-24 h after a 1-h aerosol exposure with a calculated total passage of 6.4 +/- 1.8% of the given dose. dDAVP serum levels measured by RIA peaked after 0.5-1 h, giving a total passage of 84.3 +/- 12.9%. With increasing exposure periods from 0.5 to 3 h, which thereby increased the lung burden, the serum levels of BSA and dDAVP increased linearly indicating passive transepithelial transport processes for both molecules. For the young rats, similar serum level-time curves were obtained like those of the adult, with similar total passages of BSA, 4.6 +/- 0.8% for the 14-day-old rats and 5.2 +/- 1.6% for the 30-day-old rats. For dDAVP the total passage was significantly lower in both the 14-day-old rats, 40.9 +/- 12.1%, and the 30-day-old rats, 16.7 +/- 6.1% (p less than .05), as compared to the adult rats. Acute lung inflammation induced in rats by intratracheal instillation of 5 mg ferritin/kg body wt prior to a 1-h marker aerosol exposure increased the passage of BSA (58.7 +/- 18.8%, p less than .05), while the dDAVP passage was less affected (99.2 +/- 25.2%, p greater than .05) as compared to the healthy adult rats. The results indicate that after aerosol exposure the total passage of dDAVP over the respiratory tract was higher than that of the macromolecule BSA, the passage appeared to increase with the maturity of the rats and by inflammatory changes in the lung tissue.

Regional sensitivity of the respiratory tract to stimuli causing cough and reflex bronchoconstriction

Sensory nerves mediating cough and reflex bronchoconstriction have a non-uniform distribution in the respiratory tract. Afferent nerves originating in the laryngeal region differ from those of the intrapulmonary airways in their responsiveness to physical events in the breathing cycle and to chemical stimuli. Also, within each site afferents with separate characteristics are present. Studies in animals and human subjects have shown that the larynx and the carina are particularly sensitive to mechanical stimuli, whereas the intrapulmonary airways seem to be more sensitive to mediators and irritants. Based on recent data, the importance of the intrapulmonary airways to mediator/irritant-induced cough and reflex bronchoconstriction is emphasized. Inferentially, drugs inhibiting afferent neural activity arising in intrapulmonary airways would be a novel possibility in the treatment of cough and reflex bronchoconstriction.

The tryptase inhibitor APC-366 reduces the acute airway response to allergen in pigs sensitized to Ascaris suum

Background Tryptase is a mast cell serine protease that is released during mast cell degranulation. It has been implicated as an important enzyme in the pathophysiology of asthma, but its role in this disease is not fully elucidated.

Bone marrow progenitors in allergic airways diseases: studies in canine and human models.

In a canine model of Ascaris suum-inducible bronchial hyperresponsiveness, we previously demonstrated that bone marrow-derived myeloid progenitors rise within 24 h of allergen inhalation; this effect is abolished by pretreatment with inhaled budesonide. We now report that this allergen-induced bone marrow response is observable in human asthmatics, and involves increases in both neutrophil-macrophage and eosinophil-basophil progenitors, within 6 h of allergen inhalation, as measured either by hematopoietic colony assays or by flow cytometric analyses of CD34+, IL-3R alpha+, and/or IL-5-responsive cell populations. In dogs, but not in humans, a transferrable serum hematopoietic activity accounts for the marrow response to inhaled allergen. These findings suggest that allergen-induced increases in bone marrow progenitor formation depend either on a serum hematopoietic factor(s) released after allergen challenge, or upon constitutive marrow upregulation of specific progenitors in allergic airway disease. Further studies to characterize the serum hematopoietic factor(s) and to determine the nature of any atopy-related progenitor profile are in progress.

Genetic and environmental influence on lung function impairment in Swedish twins

BackgroundThe understanding of the influence of smoking and sex on lung function and symptoms is important for understanding diseases such as COPD. The influence of both genes and environment on lung function, smoking behaviour and the presence of respiratory symptoms has previously been demonstrated for each of these separately. Hence, smoking can influence lung function by co-varying not only as an environmental factor, but also by shared genetic pathways. Therefore, the objective was to evaluate heritability for different aspects of lung function, and to investigate how the estimates are affected by adjustments for smoking and respiratory symptoms.MethodsThe current study is based on a selected sample of adult twins from the Swedish Twin Registry. Pairs were selected based on background data on smoking and respiratory symptoms collected by telephone interview. Lung function was measured as FEV1, VC and DLco. Pack years were quantified, and quantitative genetic analysis was performed on lung function data adjusting stepwise for sex, pack years and respiratory symptoms.ResultsFully adjusted heritability for VC was 59% and did not differ by sex, with smoking and symptoms explaining only a small part of the total variance. Heritabilities for FEV1 and DLco were sex specific. Fully adjusted estimates were10 and 15% in men and 46% and 39% in women, respectively. Adjustment for smoking and respiratory symptoms altered the estimates differently in men and women. For FEV1 and DLco, the variance explained by smoking and symptoms was larger in men. Further, smoking and symptoms explained genetic variance in women, but was primarily associated with shared environmental effects in men.ConclusionDifferences between men and women were found in how smoking and symptoms influence the variation in lung function. Pulmonary gas transfer variation related to the menstrual cycle has been shown before, and the findings regarding DLco in the present study indicates gender specific environmental susceptibility not shown before. As a consequence the results suggest that patients with lung diseases such as COPD could benefit from interventions that are sex specific.

Identification of patients with chronic obstructive pulmonary disease (COPD) by measurement of plasma biomarkers

Introduction:  Inflammation is an important constituent of the pathology of chronic obstructive pulmonary disease (COPD), leading to alveolar destruction and airway remodelling.