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Chronic obstructive pulmonary disease (COPD) is induced by cigarette smoking and characterized by inflammation of airway tissue. Since smokers with COPD have a higher risk of developing lung cancer than those without, we hypothesized that they carry more mutations in affected tissue. We called somatic mutations in airway brush samples from medium-coverage whole genome sequencing data from healthy never and ex-smokers (n = 8), as well as from ex-smokers with variable degrees of COPD (n = 4). Owing to the limited concordance of resulting calls between the applied tools we built a consensus, a strategy that was validated with high accuracy for cancer data. However, consensus calls showed little promise of representing true positives due to low mappability of corresponding sequence reads and high overlap with positions harbouring known genetic polymorphisms. A targeted re-sequencing approach suggested that only few mutations would survive stringent verification testing and that our data did not allow the inference of any difference in the mutational load of bronchial brush samples between former smoking COPD cases and controls. High polyclonality in airway brush samples renders medium-depth sequencing insufficient to provide the resolution to detect somatic mutations. Deep sequencing data of airway biopsies are needed to tackle the question.

Objective: Review data obtained from high-frequency oscillatory ventilation (HFOV) and mechanical test lung models with respect to delivered tidal volume, distal pressure transmission, endotracheal tube cuff leaks, and simulated clinical conditions., Design: Review of selected studies from PubMed, published abstracts, and institutional mechanical test lung data., Results: Tidal volume delivery during HFOV is altered by oscillatory pressure amplitude (DeltaP), frequency (Hz), percent inspiratory time (IT%), and patient variables. Distal (carinal) oscillatory pressure amplitude transmission is directly correlated with endotracheal tube diameter and peripheral airway resistance. Endotracheal tube cuff leaks promote egress of tracheal gas while attenuating distal oscillatory pressure amplitude and tidal volume transmission. Simulated clinical conditions (e.g., increased distal airway resistance, mainstem intubation) may increase observed DeltaP, whereas mean airway pressure is decreased with air leaks., Conclusion: Mechanical test lung and artificial trachea simulations may provide useful information on the interaction of HFOV with altered lung mechanics and may contribute to the formulation of HFOV clinical strategies. Important limitations of these models include absence of gas exchange, histologic and biologic markers, or hemodynamic data.

Background: Chronic eosinophilic pneumonia is a rare idiopathic disorder. role the eosinophil plays in the pathogenesis of this disease is unknown. The recent finding that nature eosinophils can express the class II major histocompatibility complex molecule HLA-DR suggests an immunologic role, perhaps through antigen presentation. The purpose of this research was to determine whether lung-derived eosinophils exhibit in vivo expression of HLA-DR., Methods: Eosinophils were obtained simultaneously from bronchoalveolar lavage and peripheral blood from a 59-year-old woman with asthma and chronic eosinophilic pneumonia. Eosinophil-enriched aliquots of peripheral blood were cocultured with human lung fibroblasts (with or without additional granulocyte-macrophage colony-stimulating factor). The percentage of cells expressing HLA-DR was quantitated by flow cytometric analysis., Results: Eosinophils derived from bronchoalveolar lavage displayed in vivo expression of HLA-DR (86%) in contrast to those from peripheral blood (7%), suggesting compartmentalization of eosinophil activation within the lung. Peripheral blood eosinophils retained the capacity for HLA-DR expression when coincubated with lung fibroblasts (83%) with augmentation by granulocyte-macrophage colony-stimulating factor (93%)., Conclusion: These data demonstrate that lung eosinophil HLA-DR expression occurs in vivo; it may contribute to the pathogenesis of inflammatory lung injury.

Pulmonary fibrosis resulting from diverse etiologies is characterized by proliferation of fibroblasts and excessive accumulation of interstitial collagen. Whether fibrosis is associated with selective expansion of fibroblast subpopulations differing in amounts or types of collagens synthesized is unknown. We have previously isolated lines and clones of normal murine lung fibroblasts based on the presence of the Thy 1 surface antigen. These subpopulations differ in morphology, growth characteristics, and display of class II major histocompatibility complex antigens (R.P. Phipps, D.P. Penney, P. Keng, H. Quill, A. Paxhia, S. Derdak, and M. E. Felch. Am. J. Respir. Cell Mol. Biol. 1: 65-74, 1989). We evaluated the amounts and types of collagen and fibronectin synthesized by Thy 1+ (Fib2-T-3+) and Thy 1- (Fib2-T-4-) lung fibroblast lines and clones. Thy 1+ fibroblast line synthesized two- to threefold more collagen and noncollagen protein than the Thy 1- line. In contrast, both the Thy 1+ and Thy 1- lines synthesized similar amounts of fibronectin. Thy 1+ and Thy 1- lines and clones expressed mRNA for alpha 1(I)-and alpha 1(III)-procollagen and synthesized both types (predominantly type I and lesser amounts of type III) of collagen, protein, and mRNA. The fibroblast clones varied significantly in total collagen and fibronectin production, with one Thy 1- clone (D3) synthesizing the largest amount of collagen but relatively little fibronectin.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibrotic development is a common response of the lung to toxic or deleterious insult. For example, the lung is the dose-limiting organ for irradiation of the thorax for primary or metastatic lesions, due in large part to latent fibrosis. The development of the fibrotic response reflects a cascade of cell-cell and cell-extracellular matrix interactions, the ultimate target of which is the fibroblast. There is increasing evidence of subpopulations of pulmonary fibroblasts, which may have differing roles in either the initiation or progression of fibrosis. Recently we described two fibroblast subpopulations from the murine lung, which differ in the presence or absence of the membrane antigen Thy-1 (Phipps et al., 1989). These Thy-1+ and Thy-1- subpopulations are stable and differ in certain functions, such as the production of cytokines and the display of Class II MHC antigens. To determine the morphologic development of the two subpopulations and their growth characteristics in vitro, cultures of the two cell subtypes were prepared for transmission and scanning electron microscopy at varying stages of growth. Thy-1+ fibroblasts are more spindle-shaped, contain intracellular lipid, exhibit abundant cell-cell contacts, and are capable of secreting large amounts of collagen and modest amounts of fibronectin. Thy-1- fibroblasts are more rounded and spread, contain no intracellular lipid droplets, possess more intracellular microfilaments and microtubules, and synthesize less collagen and more fibronectin than do Thy-1+ cells. There are no significant differences between the two subpopulations insofar as growth rates are concerned, but Thy-1+ fibroblasts possess an additional DNA peak during periods of early growth.

We have determined that murine lung fibroblasts are divisible into two major subpopulations based on expression of Thy 1. Twenty-four to fifty-three percent of freshly isolated lung cells displayed Thy 1 and were separated using FACS into Thy 1+ and Thy 1- fractions for morphologic examination. Analysis by electron microscopy revealed that both the Thy 1+ and Thy 1- fractions contained fibroblasts. Freshly isolated lung cells cultured for 2 wk consisted of greater than 95% fibroblasts, with 28 to 49% displaying Thy 1. These cells were sorted by FACS into Thy 1+ and Thy 1- lines that maintained a stable phenotype over many weeks and that were used as a source to obtain stable fibroblast clones. Adherent pulmonary fibroblasts are not phagocytic and lack the markers of macrophages, dendritic cells, B lymphocytes, and T lymphocytes (with the exception of Thy 1). Interestingly, the Thy 1- fibroblasts spread more and contained a more extensive microfilament and microtubule network than did the spindly and often lipid-containing Thy 1+ population. Both populations of fibroblasts synthesized collagen. Class I MHC expression was very low on Thy 1+ and Thy 1- fibroblasts, but high levels were displayed after gamma-IFN treatment. Most exciting was the unexpected finding that only the Thy 1- lines and clones displayed class II MHC (Ia) in response to treatment with gamma-IFN. Moreover, only the Thy 1- fraction (gamma-IFN-treated) presented antigen to T lymphocyte clones, an observation that suggests that this subset of cells may be involved primarily in promoting chronic lung inflammation, which is associated with developing fibrosis. Thus, two populations of pulmonary fibroblasts exist, defined by the expression of Thy 1, distinguishing morphology, inducibility for Ia expression, and antigen-presenting function. It should now be possible, using these characteristics, to ascertain the role of pulmonary fibroblast subpopulations in developing fibrosis.