Health Equity Achievement in Radiation Therapy (HEART) Score: A Social Prognosis

PURPOSE/OBJECTIVE(S)

The aim of this study was to develop a Health Equity Achievement in Radiation Therapy (HEART) score that can help identify patients at risk of experiencing suboptimal quality-of-care (QoC) early on in the patient-provider encounter and prior to initiation of treatment. Such a score may improve shared decision making to improve QoC.

MATERIALS/METHODS

A retrospective analysis was conducted using the National Cancer Database (NCDB) for prostate cancer cases between 2004-2017. Sociodemographic factors, clinical characteristics, and treatment information were collected. A composite HEART score was built to predict suboptimal QoC, defined as treatment refusal, incomplete treatment, or treatment delay. 70% of the data was allocated to training and 30% to validating a logistic regression model through which a nomogram was constructed.

RESULTS

A total of 1,599,785 patients were included in the analysis, of whom 126,917 (7.9%) had at least one suboptimal QoC. The strongest predictors were Black race, uninsured status, lower educational status, geographic location, and nodal disease (Table). The nomogram demonstrated a fair ability to predict quality metrics, with an area under the receiver operating characteristic curve (AUC) of 0.57 in the test group. The nomogram facilitated graphic interpretation of systemic factors in contributing to suboptimal QoC.

CONCLUSION

With observed potential for predicting suboptimal QoC outcomes in patients with prostate cancer by considering systemic barriers, this NCDB-based nomogram has potential utility as a tool for identifying patients who may benefit from additional social support, including the financial resources associated with these services, to improve access to care. Further validation in diverse datasets is needed to improve performance and generalizability to broader patient populations and different disease sites.

Prognostic Impact of a Negative Central Pelvic Biopsy after Definitive Chemoradiotherapy (CRT) for Locally Advanced Cervical Cancer (LACC)

PURPOSE/OBJECTIVE(S)

Central pelvic biopsies are occasionally performed during post-treatment surveillance of locally advanced cervical cancer (LACC) after a change in symptoms, abnormal pelvic exam, pap smear or imaging. Although it is established that a positive result is considered disease recurrence, it is unclear the prognostic impact of a negative biopsy. Here, we investigated the characteristics and the clinical course of patients with negative biopsy, focusing on central pelvic recurrence.

MATERIALS/METHODS

Our institutional database of female patients with diagnosis of cervical cancer treated with definitive CRT was retrospectively reviewed (2013-2022). The central pelvic region was subdivided in: I) cervix, II) endocervix/endometrium, III) vagina, IV) vulva, V) bladder and VI) rectum. Each subsite sampled was considered a distinct biopsy event, but multiple samples from one subsite at the same procedure were considered one biopsy event. We calculated the rate of initial negative and positive biopsies. The central pelvic control (local recurrence rate [LCRR]) for patients with negative biopsy was estimated with Kaplan Meier method.

RESULTS

Two hundred and twenty-five consecutive patients were included (initial FIGO 2018 staging: 30% I/II and 70% III-IVA). Of these, 66 (29.3%) underwent 112 central pelvic biopsies (average 1.7 per patient) during a median follow up time of 27.1 months [range: 0.2-94.0], with median time from treatment to first biopsy of 7.0 months [range: 1.0-41.7]. Biopsies were triggered by: symptoms/physical exam in 83 (73.4%), imaging abnormalities in 21 (18.6%), and abnormal pap smear in 9 (8%). The most common structures biopsied were: cervix (53.6%, n = 60), vagina (17.9%, n = 20), endocervix/endometrium (11.6%, n = 13), rectum/sigmoid (11.6%, n = 13), bladder (4.5%, n = 5) and vulva (0.9%, n = 1). Overall, 13.6% cases (9/66) had an initial positive biopsy, while 86.4% (57/66) had an initial negative biopsy. Of these patients with negative biopsies, 84.2% (48/57) remained without evidence of local recurrence and 15.8% (9/57) were subsequently diagnosed with local disease recurrence (1y post-biopsy LCRR 15.0% [95% CI 4.8-24.0]).

CONCLUSION

Although most (>85%) post-treatment central pelvic biopsies are negative, these patients are still at considerable risk of early local recurrence thereafter (post-biopsy 1y-LCRR 15%). Strategies to intensify surveillance may be beneficial in the first year after a negative biopsy.

Human bronchial and parenchymal fibroblasts display differences in basal inflammatory phenotype and response to IL-17A

BACKGROUND

Chronic inflammation, typified by increased expression of IL-17A, together with airway and parenchymal remodelling are features of chronic lung diseases. Emerging evidence suggests that phenotypic heterogeneity of repair and inflammatory capacities of fibroblasts may contribute to the differential structural changes observed in different regions of the lung.

OBJECTIVE

To investigate phenotypic differences in parenchymal and bronchial fibroblasts, either in terms of inflammation and remodelling or the ability of these fibroblasts to respond to IL-17A.

METHODS

Four groups of primary fibroblasts were used: normal human bronchial fibroblast (NHBF), normal human parenchymal fibroblast (NHPF), COPD human bronchial fibroblast (CHBF) and COPD human parenchymal fibroblast (CHPF). Cytokine and extracellular matrix (ECM) expression were measured at baseline and after stimulation with IL-17A. Actinomycin D was used to measure cytokine mRNA stability.

RESULTS

At baseline, we observed higher protein production of IL-6 in NHPF than NHBF, but higher levels of IL-8 and GRO-α in NHBF. IL-17A induced a higher expression of GRO-α (CXCL1) and IL-6 in NHPF than in NHBF, and a higher level of IL-8 expression in NHBF. IL-17A treatment decreased the mRNA stability of IL-6 in NHBF when compared with NHPF. CHPF expressed higher protein levels of fibronectin, collagen-I and collagen-III than CHBF, NHBF and NHPF. IL-17A increased fibronectin and collagen-III protein only in NHPF and collagen-III protein production in CHBF and CHPF.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings provide insight into the inflammatory and remodelling processes that may be related to the phenotypic heterogeneity of fibroblasts from airway and parenchymal regions and in their response to IL-17A.

Monocyte-derived fibrocytes induce an inflammatory phenotype in airway smooth muscle cells

BACKGROUND

Infiltration of fibrocytes (FC) in the airway smooth muscle is a feature of asthma, but the pathological significance is unknown.

OBJECTIVE

We sought to explore whether FC modulate the phenotype of airway smooth muscle cells (ASMC) in asthmatic vs. control subjects.

METHODS

Fibrocytes were isolated from CD14+ monocytes from asthmatic and normal subjects. Proliferation of ASMC of asthmatic or normal subjects was analysed by (3) H-thymidine incorporation, cell number counting and Ki-67 expression after treatment of ASMC with FC-conditioned medium (FCCM) or co-culture with FC. ASMC-associated cytokines/chemokines implicated in asthma (TGF-β1, eotaxin, IL-6 and IL-8) were measured in co-culture or transwell culture of ASMC + FC by ELISA. Immunofluorescence staining was performed to localize these cytokines in ASMC. Cytokine secretion was measured in the transwell culture of ASMC + FC, where NF-κB-p65 or ERK1/2 in ASMC was silenced by siRNA. Contractile phenotype of ASMC in transwell culture was assessed by immunoblotting of α-smooth muscle actin (α-SMA) and myosin light chain kinase (MLCK).

RESULTS

Fibrocytes did not affect ASMC proliferation and expression of TGF-β1, eotaxin, α-SMA and MLCK; however, ASMC production of IL-8 and IL-6 was increased in the co-culture and transwell culture by FC. ASMC treated with FCCM were immunopositive for IL-8/IL-6 and produced more IL-8/IL-6. Furthermore, siRNA silencing of NF-κB-p65 or ERK1/2 in transwell cultures of asthmatic ASMC with normal subject FC decreased IL-8 and IL-6 production.

CONCLUSIONS AND CLINICAL RELEVANCE

Fibrocytes promoted IL-8 and IL-6 production by ASMC, demonstrating a proinflammatory role for FC and a possible mechanism of the inflammatory phenotype in asthma.

Epidemiology of subacute sclerosing panencephalitis (SSPE) in Germany from 2003 to 2009: a risk estimation

Subacute sclerosing panencephalitis (SSPE) is a fatal long-term complication of measles infection. We performed an estimation of the total number of SSPE cases in Germany for the period 2003 to 2009 and calculated the risk of SSPE after an acute measles infection. SSPE cases were collected from the Surveillance Unit for Rare Paediatric Diseases in Germany and the Institute of Virology and Immunobiology at the University of Würzburg. The total number of SSPE cases was estimated by capture-recapture analysis. For the period 2003 to 2009, 31 children with SSPE who were treated at German hospitals were identified. The capture-recapture estimate was 39 cases (95% confidence interval: 29.2–48.0). The risk of developing SSPE for children contracting measles infection below 5 years of age was calculated as 1∶1700 to 1∶3300. This risk is in the same order of magnitude as the risk of a fatal acute measles infection.

Mechanical strain increases cytokine and chemokine production in bronchial fibroblasts from asthmatic patients

BACKGROUND

Mechanical strain and cytokine stimulation are two important mechanisms leading to airway remodeling in asthma. The effect of mechanical strain on cytokine secretion in airway fibroblasts is not known. The aim of this study was to determine whether bronchial and nasal fibroblasts differentially alter cytokine secretion in response to mechanical strain.

METHODS

We measured secretion of the pro-fibrotic cytokine, interleukin-6 (IL-6), and the pro-inflammatory cytokines, IL-8 and monocyte chemotactic protein 1, before and after mechanical strain in bronchial fibroblasts obtained from asthmatic patients [asthmatic bronchial fibroblasts (BAF)] and normal volunteers [normal bronchial fibroblasts (BNF)], and in nasal fibroblasts (NF) obtained from nasal polyps. Cells were grown on flexible membranes and a mechanical strain of 30% amplitude, 1 Hz frequency was applied for 3, 6 and 24 h. Control cells were unstrained. IL-6, IL-8 and monocyte chemotactic protein 1 was measured after 24 h strain using enzyme-linked immunoassay; mRNA was measured by real time polymerase chain reaction. We also measured mRNA for versican, a matrix proteoglycan, known to be upregulated in the asthmatic airway wall.

RESULTS

In unstrained conditions, no differences in cytokine secretion were observed. After 24 h strain, BAF secreted more IL-6 than BNF. Mechanical strain increased IL-8 mRNA in BAF, BNF and NF; and IL-6 and versican mRNA, in BAF, only.

CONCLUSIONS

Cytokine responses to mechanical strain varied in different airway fibroblast populations, and depended on the site of origin, and the underlying inflammatory state. Strain resulted in IL-6 upregulation and increased message for extracellular matrix protein in bronchial fibroblasts from asthmatic patients only, and may reflect these patients' propensity for airway remodeling.

An ongoing multi-state outbreak of measles linked to non-immune anthroposophic communities in Austria, Germany, and Norway, March-April 2008

From the second week of March 2008, public health authorities in the province of Salzburg observed an increased number of measles cases compared to previous years. Twenty cases of measles had been were notified Austria-wide in 2007, 24 in 2006, 10 in 2005, and 14 in 2004. The current outbreak has affected, as of 14 April, 202 people in Austria, 53 in Germany, and four in Norway, bringing the total number of cases related to this outbreak to 259. The initial case series investigation revealed that the common link was attendance of an anthroposophic school and day care centre in Salzburg city. The majority of the pupils were not vaccinated against measles.

An outbreak of measles in Lower Bavaria, Germany, January-June 2007

Between January and June 2007, a total of 90 cases of measles were notified in Passau and Rottal-Inn, two districts of Lower Bavaria in south-east Germany sharing a border with Austria.

Differences in proteoglycan deposition in the airways of moderate and severe asthmatics

Excess deposition of proteoglycans (PGs) has been described in the subepithelial layer of the asthmatic airway wall. However, less is known about deposition in the airway smooth muscle (ASM) layer, and whether the pattern of deposition is altered depending upon disease severity. Endobronchial biopsies were performed in patients with severe or moderate asthma (defined using American Thoracic Society criteria) and in control subjects. Biopsies were immunostained for the PGs biglycan, lumican, versican and decorin. PG deposition was measured in the subepithelial and ASM layers, the former by calculating the area of positive staining, and the latter by determining the percentage area stained using point counting. Immunostaining for PGs was prominent in biopsies from both moderate and severe asthmatics, compared with control subjects. While there was no difference in the amount of PG in the subepithelial layer between the two asthmatic groups, the percentage area of biglycan and lumican staining in the ASM layer was significantly greater in moderate versus severe asthmatics. Differences in the deposition of proteoglycans within the airway smooth muscle layer of moderate versus severe asthmatics potentially impact on the functional behaviour of the airway smooth muscle in these two groups of patients.

Changes in Smad expression and subcellular localization in bleomycin-induced pulmonary fibrosis

Administration of bleomycin (BM) produces inflammation and fibrosis of the lung in humans and experimental animals. The molecular defects by which BM induces these pathological effects have not been studied in detail. We studied the expression of Smad family proteins, key molecules involved in mediating transforming growth factor (TGF)-β signaling from the cell membrane to the nucleus, during the early and late phases of BM-induced fibrogenesis. Pulmonary fibrosis was induced in male Sprague-Dawley rats by a single intratracheal injection (1.5 units) of BM. Control rats received saline. Rats were killed at 3, 5, 7, 14, and 28 days after BM, cytosolic and nuclear proteins were extracted and isolated from lung tissues, and Smad proteins were probed with specific antibodies. In BM-exposed lung tissue, compared with control, Smad3 decreased persistently in the cytosol and increased transiently in the nucleus. There was a persistent increase in phosphorylation and nuclear accumulation of Smad2/3. Smad4 was increased transiently in both the cytosol and nucleus. A significant and progressive decrease in the expression of Smad7, the endogenous inhibitor of TGF-β/Smad signaling, was observed after BM instillation. Collectively, our results indicate that an imbalance between agonistic Smads2–4 and antagonistic Smad7 may result in the unchecked activation of an autocrine TGF-β loop, which contributes to the pathogenesis of BM-induced pulmonary fibrosis.

Mechanical strain enhances proteoglycan message in fibroblasts from asthmatic subjects

BACKGROUND

Remodelling of the asthmatic airway includes increased deposition of proteoglycan (PG) molecules. One of the stimuli driving airway remodelling may be excessive mechanical stimulation.

OBJECTIVE

We hypothesized that fibroblasts from asthmatic patients would respond to excessive mechanical strain with up-regulation of message for PGs.

METHODS

We obtained fibroblasts from asthmatic patients (AF) and normal volunteers (NF) using endobronchial biopsy. Cells were maintained in culture until the fifth passage and then grown on a flexible collagen-coated membrane. Using the Flexercell device, cells were then subjected to cyclic stretch at 30% amplitude at 1 Hz for 24 h. Control cells were unstrained. Total RNA was extracted from the cell layer and quantitative RT-PCR performed for decorin, lumican and versican mRNA.

RESULTS

In unstrained cells, the expression of decorin mRNA was greater in AF than NF. With strain, NF showed increased expression of versican mRNA and AF showed increased expression of versican and decorin mRNA. The relative increase in versican mRNA expression with strain was greater in AF than NF.

CONCLUSIONS

These data support the hypothesis that proteoglycan message is increased in asthmatic fibroblasts subject to mechanical strain. This finding has implications for the mechanisms governing airway wall remodelling in asthma.

Stretch-induced changes in constricted lung parenchymal strips: role of extracellular matrix

Large amplitude oscillations of contracted airway smooth muscle cause relative relaxation of the preparation. However, little is known about the effect of mechanical stretch on distal lung behaviour. Rat parenchymal strips were suspended in an organ bath and attached at one end to a force transducer and at the other end to a servo-controlled lever arm that effected length changes. Mechanical impedance of the strip was measured by applying a complex signal consisting of pseudorandom length oscillations of varying frequencies (0.5-19.75 Hz). A constant phase model was fit to changes in length and tension to calculate tissue damping (G) and elastance (H). Hysteresivity was calculated as G/H. Impedance was measured before and after sinusoidal length oscillation at different amplitudes (1, 3, 10 and 25% of resting length) at a frequency of 1 Hz under baseline conditions and after acetylcholine-induced constriction. Oscillations of 10 and 25% amplitudes significantly decreased the G and H of the lung strip. The effect of length oscillations was no different in control versus constricted strips. These data suggest that in the distal lung, large stretches affect the structural components of the extracellular matrix rather than the contractile elements.

Changes in proteoglycans and lung tissue mechanics during excessive mechanical ventilation in rats

Excessive mechanical ventilation results in changes in lung tissue mechanics. We hypothesized that changes in tissue properties might be related to changes in the extracellular matrix component proteoglycans (PGs). The effect of different ventilation regimens on lung tissue mechanics and PGs was examined in an in vivo rat model. Animals were anesthetized, tracheostomized, and ventilated at a tidal volume of 8 (VT(8)), 20, or 30 (VT(30)) ml/kg, positive end-expiratory pressure of 0 (PEEP(0)) or 1.5 (PEEP(1.5)) cmH(2)O, and frequency of 1.5 Hz for 2 h. The constant-phase model was used to derive airway resistance, tissue elastance, and tissue damping. After physiological measurements, one lung was frozen for immunohistochemistry and the other was reserved for PG extraction and Western blotting. After 2 h of mechanical ventilation, tissue elastance and damping were significantly increased in rats ventilated at VT(30)PEEP(0) compared with control rats (ventilated at VT(8)PEEP(1.5)). Versican, basement membrane heparan sulfate PG, and biglycan were all increased in rat lungs ventilated at VT(30)PEEP(0) compared with control rats. At VT(30)PEEP(0), heparan sulfate PG and versican staining became prominent in the alveolar wall and airspace; biglycan was mostly localized in the airway wall. These data demonstrate that alterations in lung tissue mechanics with excessive mechanical ventilation are accompanied by changes in all classes of extracellular matrix PG.

Maturational changes in extracellular matrix and lung tissue mechanics

The viscoelastic properties of the pulmonary parenchyma change rapidly postparturition. We compared changes in mechanical properties with changes in tissue composition of rat lung parenchymal strips in three groups of Sprague-Dawley rats: baby (B; 10-14 days), young (Y; approximately 3 wk), and adult (A; approximately 8 wk). Strips were suspended in an organ bath, and resistance (R), elastance (E), and hysteresivity (eta) were calculated during sinusoidal oscillations before and after the addition of acetylcholine (ACh) (10(-3) M). Strips were then fixed in formalin, and sections were stained with hematoxylin and eosin, Verhoff's elastic stain, or Van Gieson's picric acid-fuchsin stain for collagen. The volume proportion of collagen (%Col), the length density of elastic fibers (L(V)/Pr(alv)), and the arithmetic mean thickness of alveolar septae (T(a)) were calculated by morphometry. Tissue was also stained for alpha-smooth muscle actin (ASMA), and the volume proportion of ASMA (%ASMA) was calculated. Hyaluronic acid (HA) was quantitated by radioimmunoassay in separate strips. R and E in B strips were significantly higher, whereas eta was significantly smaller than in Y or A strips. Changes in these parameters with ACh were greater in B strips. T(a), %ASMA, and HA were greatest in B strips, whereas %Col and L(V)/Pr(alv) were least. There were significant positive correlations between R and E vs. T(a) and between percent change in R and eta post-ACh vs. T(a) and vs. %ASMA, and significant negative correlations between R and E vs. %Col and vs. L(V)/Pr(alv) and percent increase in all three mechanical parameters post-ACh vs. %Col. These data suggest that the relatively high stiffness, R, and contractile responsiveness of parenchymal tissues observed in newborns are not directly attributable to the amount of collagen and elastic fibers in the tissue, but rather they are related to the thickened alveolar wall and the relatively greater percent of contractile cells.

Cancer prevention and the contribution of cancer registries

"Because they know what they do" should be the contribution of cancer registration to prevention. The public should be informed about the successes and failures of prevention. In addition, each doctor and each hospital should know the long-term results for its patients despite the complex interdisciplinary health care provision. At the same time, the regional results should be available and contrasted with clinical studies and international standards. An important criterion is also the quality of life of the patients, whose cooperation is more than overdue. According to the possibilities of prevention, six important levels can be differentiated. On each level the outcome should be evaluated on the basis of slightly differing criteria. Primary prevention has the largest incidence-, and thus, mortality-reduction potential, essentially caused by the giving up of smoking. However, the primary prevention of the tumor depends upon what kind of tumor it is, as primary prevention is possible to different extents. Often, secondary prevention is the earliest intervention possible, that is, the early detection of cancer in prognostically favorable stages. However, early detection only offers a chance of cure, albeit a smaller one, for some kinds of tumor. The third prevention level comprises primary care according to the state-of-the-art standards, followed by posttreatment care (disease-free phase) even when the disease is running a fatal course (palliative phase). In the terminal phase, adequate tumor-pain therapy and symptom-oriented measures stand for the sixth prevention level. Even the quality of life of the dying can be optimized. At the beginning of treatment at the latest, the quality of life should also be added to the outcome criteria. In this paper, the individual levels of prevention and possible evaluation criteria for successful prevention, which a modern cancer registration should submit, are discussed and examples given. If the evaluation of the quality of treatment and its significance for health care provision becomes the central tasks of the cancer registers, they will need to be transformed into service centers for hospitals, doctors, and patients.

Effect of glycosaminoglycan degradation on lung tissue viscoelasticity

We tested the hypothesis that matrix glycosaminoglycans contribute to lung tissue viscoelasticity. We exposed lung parenchymal strips to specific degradative enzymes (chondroitinase ABC, heparitinase I, and hyaluronidase) and determined whether the mechanical properties of the tissue were affected. Subpleural parenchymal strips were obtained from Sprague-Dawley rats and suspended in a Krebs-filled organ bath. One end of the strip was attached to a force transducer and the other to a servo-controlled lever arm that effected sinusoidal oscillations. Recordings of tension and length at different amplitudes and frequencies of oscillation were recorded before and after enzyme exposure. Resistance, dynamic elastance, and hysteresivity were estimated by fitting the equation of motion to changes in tension and length. Quasi-static stress-strain curves were also obtained. Exposure to chondroitinase and heparitinase I caused significant increases in hysteresivity, no decrement in resistance, and similar decreases in dynamic elastance relative to control strips exposed to Krebs solution only. Conversely, measures of static elastance were different in treated versus control strips. Hyaluronidase treatment did not alter any of the mechanical measures. These data demonstrate that digestion of chondroitin sulfate and heparan sulfate alters the mechanical behavior of lung parenchymal tissues.

Changes in extracellular matrix and tissue viscoelasticity in bleomycin-induced lung fibrosis. Temporal aspects

Bleomycin-induced lung fibrosis results in changes in tissue mechanical properties due to alterations in the extracellular matrix (ECM). How oscillatory mechanics and changes in the matrix evolve over time has not been addressed. Sprague-Dawley rats were instilled with bleomycin sulfate (BM) (1.5 U) intratracheally; control animals (C) received saline. At 7, 14, and 28 d after BM, parenchymal strips (7 x 2 x 2 mm) were obtained and strips suspended in a Krebs-filled organ bath. One end of the strip was attached to a force (F) transducer and the other to a lever arm that effected sinusoidal length (L) oscillations. Strips were oscillated at varying amplitudes (1, 3, and 10% of resting L) and frequencies (f = 0.3, 1, 3, and 10 Hz) at an operating stress of 2 kPa. Resistance (R) and elastance (E) were estimated by fitting changes in F and L to the equation of motion. Hysteresivity (eta) was calculated as eta = (R/E) 2pif. Strips were then fixed for morphological study of collagen, elastic fibers, and the small proteoglycans (PGs), biglycan and fibromodulin (FM). R and E were significantly greater and eta significantly less in BM versus C strips (p < 0.001). The increase in R and E peaked at 14 d after BM; the decrement in eta was maximal at Day 7. Biglycan was increased in BM lung strips at all time points, FM and elastic fibers were increased at 14 and 28 d, and collagen was increased at 28 d only. Hence, changes in mechanics were maximal before collagen content had increased. In addition, we demonstrated a significant correlation between biglycan and all mechanical parameters. These data suggest that changes in PGs may be critical in determining changes in lung tissue viscoelastic behavior in this fibrosis model

Alterations in large and small proteoglycans in bleomycin-induced pulmonary fibrosis in rats

In bleomycin (BM)-induced lung fibrosis, alterations have been shown in the expression and deposition of small proteoglycans (PGs). Less, however, is known about changes in large PGs. We investigated changes in large aggregating (versican [VS]), basement membrane (heparan sulfate proteoglycan [HSPG]), and small (biglycan and fibromodulin) PGs during the development of BM-induced pulmonary fibrosis. BM (1.5 U) was instilled intratracheally into male Sprague-Dawley rats. Control rats received saline. At 7, 14, and 28 d after administration of BM, lungs were excised; one lung was fixed in formalin and 5-microm sections were cut and stained with hematoxylin-eosin. The other lung was used for PG extraction. PGs were extracted with guanidine and were separated through composite gel polyacrylamide gel electrophoresis (PAGE) (large PGs) and sodium dodecylsulfate-PAGE (small PGs). Gels were either stained or electrophoretically transferred and probed with antibodies to VS, HSPG, biglycan, and fibromodulin. Histologic samples showed prominent inflammation, with abundant proteinaceous material, most evident in the samples obtained at 7 and 14 d after administration of BM. By 28 d after BM, much of the inflammatory response had resolved, and heterogeneous distribution of fibrosis was observed. Immunoblots showed a relative abundance of VS at 7 and 14 d. Control lungs stained minimally for VS. Levels of HSPG, biglycan, and fibromodulin were increased maximally at 14 d after administration of BM. Immunocytochemistry showed intense immunostaining of biglycan and fibromodulin in the areas of injured lung tissue from rats 14 and 28 d after BM administration. Control lungs revealed minimal staining for small PGs. Our findings indicate that changes in all subclasses of PGs occur during the development of BM-induced pulmonary fibrosis.

Changes in viscoelastic properties of rat lung parenchymal strips with maturation

The lung extracellular matrix changes rapidly with maturation. To further our understanding of the mechanisms underlying lung tissue mechanics, we studied age-related changes in mechanical properties in lung parenchymal strips from baby (10-15 days old), young ( approximately 3 wk old), and adult ( approximately 8 wk old) rats. Subpleural strips were cut and suspended in a fluid-filled organ bath. One end of the strip was attached to a force transducer and the other to a servo-controlled lever arm. Measurements of force (F) and length (L) were recorded during sinusoidal oscillations of various amplitudes and frequencies. Resistance modulus (R) and elastance modulus (E) were estimated by fitting the equation of motion to changes in stress (T) and stretch ratio (lambda). Hysteresivity (eta) was calculated as follows: eta = (R/E)2pif, where f is frequency. Slow-cycling T-lambda curves were measured by applying a constant slow length change. Finally, quasi-static T-lambda curves were measured as stress was increased from 0 to 6 kPa and back to 0 kPa in stepwise increments. Our results showed that lung tissue from immature rats was stiffer and less hysteretic than tissue from more mature animals. In addition, tissue from baby animals behaved in a manner compatible with an increased vulnerability to plastic change.

Extracellular matrix and oscillatory mechanics of rat lung parenchyma in bleomycin-induced fibrosis

We investigated in vivo and in vitro oscillatory mechanics in bleomycin-induced fibrotic lungs and correlated these with morphometric changes in the collagen-elastin matrix and contractile cells. Fischer rats received bleomycin sulfate (BLEO,1.5 U) or saline intratracheally. Four weeks later tracheal flow and tracheal and alveolar pressure (using alveolar capsules) were measured in open-chested rats during mechanical ventilation (V T = 8 ml/kg, f = 1 Hz, PEEP = 4 cm H(2)O). Total lung, tissue, and airway resistance (R) and lung elastance (E) were calculated. In addition, excised parenchymal strips (10 x 2 x 2 mm) were studied in the organ bath. Strips were attached to a force transducer at one end and to a servo-controlled lever arm that effected length (L) changes at the other. Sinusoidal oscillations were applied (f = 1 Hz, amplitude = 2. 5% resting L and tension = 0.7 g) and R, E, and hysteresivity (eta) were calculated. Strips were then exposed to acetylcholine (ACh, 10(-)(3) M). The amount of collagen and elastic fibers in the parenchymal strip was assessed semiquantitatively by point-counting in 5-micrometer-thick sections stained with either Sirius Red or Weigert's Resorcin-fuchsin. alpha-Smooth-muscle-specific actin was detected immunohistochemically. Both in vivo and in vitro, R, E, and eta were significantly increased in BLEO rats (p < 0.05). The % increase in R, E and eta after Ach was greater in BLEO rats (p < 0. 01). There was also a significant increase in the volume proportion of collagen, elastic fibers, and actin in the parenchyma (p < 0.01). In BLEO rats, baseline R and E were correlated with the volume proportion of collagen in the parenchyma. We conclude that changes in the collagen-elastin matrix contribute to changes in the viscoelastic properties of bleomycin-treated rat lungs. Dolhnikoff M, Mauad T, Ludwig MS. Extracellular matrix and oscillatory mechanics of rat lung parenchyma in bleomycin-induced fibrosis.

Tidal volume amplitude affects the degree of induced bronchoconstriction in dogs

When isolated constricted airway smooth muscle is oscillated, muscle tone decreases. We investigated whether changing tidal volume (VT) would affect induced bronchoconstriction in an in vivo canine model. Open-chest dogs were intubated with a double-lumen endotracheal tube, which isolated each main bronchus, and mechanically ventilated with a dual-cylinder ventilator. Bronchial pressure (Pbr) and flow were measured separately in each lung. Resistance and elastance were calculated by fitting the changes in Pbr, flow, and volume to the equation of motion. After baseline measurements at the same VT (150 ml), the two lungs were ventilated with different VT (50 vs. 250 ml) at a constant positive end-expiratory pressure. A continuous infusion of methacholine was begun, and measurements were repeated. The two lungs were then ventilated with the same VT (250 ml), and measurements were again repeated. A similar protocol was performed in a second group of dogs in which mean Pbr was kept constant. Bronchoconstriction was more severe in the lung ventilated with lower VT in both protocols. When VT was reset to the same amplitude in the two lungs, the difference in bronchoconstriction was abrogated. These results demonstrate that large VT inhibits airway smooth muscle contraction, regardless of mean Pbr.

Elastic moduli of excised constricted rat lungs

When airways constrict, the surrounding parenchyma undergoes stretch and distortion. Because of the mechanical interdependence between airways and parenchyma, the material properties of the parenchyma are important factors that modulate the degree of bronchoconstriction. The purpose of this study was to investigate the effect of changes in transpulmonary pressure (Ptp) and induced constriction on parenchymal bulk (k) and shear (mu) moduli. In excised rat lungs, pressure was measured at the airway opening, and pressure-volume curves were obtained by imposing step decreases in volume with a calibrated syringe from total lung inflation. Calculation was made of k during small-volume oscillations (1 Hz). Absolute lung volume at 0 cmH2O Ptp was obtained by saline displacement. To calculate mu, a lung-indentation test was performed. The lung surface was deformed with a cylindrical punch (diameter = 0.45 cm) in 0.25-mm increments, and the force required to effect this displacement was measured by a weight balance. Measurements of k and mu were obtained at 4 and 10 cmH2O Ptp, and again at 4 cmH2O Ptp, after delivery of methacholine aerosol (100 mg/ml) into the trachea. Values of k and mu in rat lungs were similar to those reported in other species. In addition, k and mu were dependent on Ptp. After induced constriction, k and mu increased significantly. That k and mu can increase after induced constriction has important implications vis a vis the factors modulating airway narrowing.

Human lung parenchyma responds to contractile stimulation

Tissue resistance increases after agonist challenge. Parenchymal contractile cells may be the responsible element. We investigated the viscoelastic properties of human parenchymal strips before and after challenge with acetylcholine (ACh) (10(-)3 M). Thirteen subpleural strips were oscillated in the organ bath, and measurements of resistance (R), elastance (E), and hysteresivity (eta) were obtained. After physiologic measurements, tissues were fixed for morphometric and immunohistochemical analysis. We quantitated the volume proportion of alveolar, airway, and blood vessel wall in individual strips. Smooth-muscle-specific actin was identified using a monoclonal antibody and the volume proportion of actin quantitated by point counting. After ACh, there was a significant increase in tension (2.6 +/- 0.6%), R (11.0 +/- 1.8%), E (4.3 +/- 0.7%), and eta (8.2 +/- 2.4%) (p < 0.002). Four strips contained no identifiable airways, yet in strips with and without airways there was no difference in the magnitude of the mechanical response or in the volume proportion of smooth-muscle-specific actin in the alveolar walls. We conclude that human lung parenchymal strips respond to ACh challenge with changes in dynamic mechanical behavior. Furthermore, small airways are not required for such a response to occur. This implicates a direct contractile response at the level of the alveolar wall and/or the alveolar duct.

Expression of lumican in human lungs

The collagen-elastin-proteoglycan (PG) matrix is the key constituent of lung parenchyma and plays a major role in the mechanical behavior of lung tissues. However, the exact composition of the PG matrix in lungs has not yet been fully determined. In the present study we report the expression of leucine-rich repeat PGs in adult human lungs. PG extraction was performed on peripheral lung tissue from patients undergoing therapeutic lung resections. The samples were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting using antipeptide antisera specific to human lumican, decorin, biglycan, and fibromodulin. Control experiments to verify antiserum reactivity were performed with an extract of adult human articular cartilage, which is known to contain all four PGs. In all lung extracts analyzed, a single component of molecular weight 65 to 90 kD was detected for lumican. Decorin, biglycan, and fibromodulin were either not detected or were barely detectable in the lung extracts, but were readily visualized in the cartilage samples. Immunohistochemistry showed that lumican was diffusely present in peripheral lung tissue, mainly in vessel walls. These results suggest that lumican is a major component of the PG matrix in adult human lungs.

Dissociation between hysteresivity and tension in constricted tracheal and parenchymal strips

The object of this study was to investigate how changes in the contractile state of smooth muscle would modify oscillatory mechanics of tracheal muscle and lung parenchyma during agonist challenge. Guinea pig tracheal and parenchymal lung strips were suspended in an organ bath. Measurements of length (L) and tension (T) were recorded during sinusoidal oscillations under baseline conditions and after challenge with 1 mM ACh. Measurements were also obtained in strips pretreated with the calmodulin inhibitor calmidazolium (Cmz) or staurosporine (Stauro), a protein kinase C inhibitor. Elastance (E) and resistance (R) were calculated by fitting changes in T, L, and DeltaL/Deltat to the equation of motion. Hysteresivity (eta) was obtained from the following equation: eta = (R/E)2pif, where f is frequency. Finally, maximal unloaded shortening velocity during electrical field stimulation was measured in Cmz-pretreated and control tracheal strips. In tracheal strips, pretreatment with Cmz caused a significant decrease in the eta response to ACh challenge and in maximal unloaded shortening velocity measured during electrical field stimulation; Stauro decreased the T, E, and R response to ACh. In parenchymal strips, Cmz decreased the eta response, whereas Stauro had no effect. These results suggest that modifications in the contractile state of the smooth muscle are reflected in changes in the hysteretic behavior and that T and eta may be controlled independently. Second, inasmuch as changes in eta were similar in parenchymal and tracheal strips, the contractile element is implicated as the structure responsible for constriction-induced changes in the mechanical behavior of the lung periphery.

A comparative study of elastic properties of rat and guinea pig parenchymal strips

Constricted guinea pig (GP) airways are much less sensitive to changes in transpulmonary pressure (Ptp) than are those of the rat. The object of this study was to investigate whether differences in the mechanical behavior of the lung parenchyma could explain differences between the two species in the interdependence of the airway and parenchyma. Subpleural lung strips from guinea pigs and rats were excised and suspended in an organ bath. One end of each strip was attached to a force transducer and the other to a servo-controlled lever arm that effected length (L) changes in the strip. Sinusoidal oscillations at varying frequencies and amplitudes were applied at different resting tensions. Measurements of L and resting tension (T) were recorded during baseline conditions and after acetylcholine (ACh) challenge. Elastance (E) and resistance (R) were calculated by fitting changes in T and L to the equation of motion. During sinusoidal oscillations, E and R in the two species were different in both the unconstricted and constricted states. The effect of T on E was significantly different in rats and GPs; E was less dependent on T in GPs. Insofar as E is a measure of the load against which airway smooth muscle (ASM) contracts, this difference may represent a potential mechanism to explain why constricted GP airways are less sensitive to changes in Ptp.

Antigen-induced responses in lung parenchymal strips during sinusoidal oscillation

We have recently demonstrated that tissue resistance increases during the early response to antigen challenge in sensitized Brown-Norway rats. The purpose of the present study was to investigate in vitro the dynamic tissue response to antigen challenge and the involvement of the mediators, i.e., serotonin (5HT) and leukotriene D4 (LTD4). In addition, we questioned whether strips from sensitized rats responded differently to nonspecific challenge compared with those of unsensitized controls. We sensitized Brown-Norway rats with ovalbumin and performed experiments using strips of subpleural parenchyma. Tissue strips were challenged with ovalbumin in the bath; in some experiments the tissues were exposed to methysergide (10-6 M), a 5HT antagonist, or MK-571 (10-6 M), a LTD4 receptor antagonist, or both, prior to challenge. At the end of the experiment all tissues were exposed to carbacholine (10-3 M). Oscillation mechanics of tissue strips were studied and values of resistance (R), elastance (E), and hysteresivity ( eta ) were obtained. During ovalbumin challenge in sensitized tissues, R, E, and eta increased significantly (% change in R, 12.1 ± 2.1%; % change in E, 3.8 ± 1.3%; % change in eta , 9.3 ± 2.8%). Both methysergide and MK-571 reduced the increase in R (3.0 ± 0.6 and 3.2 ± 0.8%, respectively, p < 0.05 vs. ovalbumin). There was no difference between sensitized and unsensitized strips in the response to carbacholine challenge. These data suggest that the oscillatory behaviour of tissue strips from sensitized rats is altered after ovalbumin challenge. The mechanism of that response is mediated by both 5HT and LTD4.Key words: tissue resistance, allergic asthma, serotonin, leukotrienes, hysteresis.

Antigen-induced responses in lung parenchymal strips during sinusoidal oscillation

We have recently demonstrated that tissue resistance increases during the early response to antigen challenge in sensitized Brown-Norway rats. The purpose of the present study was to investigate in vitro the dynamic tissue response to antigen challenge and the involvement of the mediators, i.e., serotonin (5HT) and leukotriene D4 (LTD4). In addition, we questioned whether strips from sensitized rats responded differently to nonspecific challenge compared with those of unsensitized controls. We sensitized Brown-Norway rats with ovalbumin and performed experiments using strips of subpleural parenchyma. Tissue strips were challenged with ovalbumin in the bath; in some experiments the tissues were exposed to methysergide (10(-6) M), a 5HT antagonist, or MK-571 (10(-6) M), a LTD4 receptor antagonist, or both, prior to challenge. At the end of the experiment all tissues were exposed to carbacholine (10(-3) M). Oscillation mechanics of tissue strips were studied and values of resistance (R), elastance (E), and hysteresivity (eta) were obtained. During ovalbumin challenge in sensitized tissues, R, E, and eta increased significantly (% change in R, 12.1 +/- 2.1%; % change in E, 3.8 +/- 1.3%; % change in eta, 9.3 +/- 2.8%). Both methysergide and MK-571 reduced the increase in R (3.0 +/- 0.6 and 3.2 +/- 0.8%, respectively, p < 0.05 vs. ovalbumin). There was no difference between sensitized and unsensitized strips in the response to carbacholine challenge. These data suggest that the oscillatory behaviour of tissue strips from sensitized rats is altered after ovalbumin challenge. The mechanism of that response is mediated by both 5HT and LTD4.

Effect of the route and mode of agonist delivery on functional behaviour of the airways

There is evidence that the mode of smooth muscle agonist delivery affects the changes induced in lung mechanical properties. The object of this investigation was to study modifications in airway behaviour associated with different modes of agonist delivery. Tracheal (Ptr) and alveolar pressure (PA) and flow (V) were measured in open-chested, mechanically ventilated (f = 1 Hz, VT = 10 ml/kg, PEEP = 4 cm H2O) rats under baseline conditions and during administration of repeated intravenous (i.v.) bolus, i.v. continuous infusion and aerosols of methacholine (MCh). We calculated lung elastance (EL) and lung resistance (RL) by fitting the equation of motion to changes in Ptr and V. We assessed the patency of the airway pathways and local dynamic hyperinflation by comparing Ptr vs PA. Comparison of the three different modes of MCh delivery showed a difference in the functional behaviour of the airways. In the aerosol group a larger incidence of highly constricted airways was observed. Conversely, the i.v. groups showed a larger incidence of regional dynamic hyperinflation. In the bolus group a different time course in the development of dynamic hyperinflation was observed for different pathways within the same animal. For consecutive challenges a given pathway tended to behave in the same manner, suggesting the response was characteristic for that pathway. In this study we have shown that, even though different airway pathways show different intrinsic reactivity, the mode of agonist delivery plays a role in determining functional airway behaviour.

Effects of lung volume on airway resistance during induced constriction in papain-treated rabbits

It has been reported that both the elasticity of the cartilage and airway-parenchymal interdependence can modify shortening of the airway smooth muscle and airway narrowing during induced constriction. We hypothesized that induced softening of the cartilage could alter airway compliance and/or the forces of mechanical interdependence, resulting in an increased degree of airway narrowing in response to a contractile stimulus. To test this hypothesis, we compared the effects of changing lung volume on airway resistance (Raw) under baseline conditions and during methacholine (MCh)-induced constriction in papain-treated (n = 6) and control rabbits (n = 6). With use of the alveolar capsule technique, Raw was directly measured under baseline conditions at different levels of end-expiratory transpulmonary pressure (Ptp = 4-12 cmH2O). Then aerosolized MCh was delivered (0.2-25 mg/ml) and measurements were performed at different levels of Ptp (4 and 12 cmH2O). From measured tracheal flow and tracheal and alveolar pressure in open-chest animals during mechanical ventilation (tidal volume = 6 ml/kg, breathing frequency = 1 Hz), we calculated Raw by subtracting tissue resistance from lung resistance. Papain treatment significantly increased Raw both under baseline conditions and after induced constriction. We found that increasing Ptp decreased Raw before and after MCh in both groups; however, the effects of changing Ptp on Raw were less in papain-treated animals. These observations suggest that both cartilage elasticity and mechanical interdependence are important determinants of airway smooth muscle shortening. The observation that volume dependence of Raw was less in papain-treated animals is consistent with the hypothesis that papain effects significant changes in the parenchymal attachments.

Characterization of the anatomical structures involved in the contractile response of the rat lung periphery

1. When lung parenchymal strips are challenged with different smooth muscle agonists, the tensile and viscoelastic properties change. It is not clear, however, which of the different anatomical elements present in the parenchymal strip, i.e., small vessel, small airway or alveolar wall, contribute to the response. 2. Parenchymal lung strips from Sprague Dawley rats were suspended in an organ bath filled with Krebs solution (37 degrees C, pH = 7.4) bubbled with 95%O2/5%CO2. Resting tension (T) was set at 1.1 g and sinusoidal oscillations of 2.5% resting length (L0) at a frequency of 1 Hz were applied. Following 1 h of stress adaptation, measurements of length (L) and T were recorded under baseline conditions and after challenge with a variety of pharmacological agents, i.e., acetylcholine (ACh), noradrenaline (NA) and angiotensin II (AII). Elastance (E) and resistance (R) were calculated by fitting changes in T, L and delta L/ delta t to the equation of motion. Hysteresivity (eta, the ratio of the energy dissipated to that conserved) was obtained from the equation eta = (R/E)2 pi f. 3. In order to determine whether small airways or small vessels accounted for the responses to the different pharmacologic agents, further studies were carried out in lung explants. Excised lungs from Sprague Dawley rats were inflated with agarose. Transverse slices of lung (0.5-1.0 mm thick) were cultured overnight. By use of an inverted microscope and video camera, airway and vascular lumen area were measured with an image analysis system. 4. NA, ACh and AII constricted the parenchymal strips. Airways constricted after all agonists, vessels constricted only after All. Atropine (Atr) pre-incubation decreased the explanted airway and vessel response to AII, but no difference was found in the parenchymal strip response. 5. Preincubation with the arginine analogue N omega-nitro-L-arginine (L-NOARG) did not modify the response to ACh but mildly increased the oscillatory response to NA after co-preincubation with propranolol (Prop). 6. These results suggest that during ACh and NA challenge, small vessels do not contribute substantially to the parenchymal strip response. The discrepancy between results in airways, vessels and strips when Atr was administered prior to AII implicates a direct contractile response in the parenchymal strip.

Airway and tissue behavior during early response in sensitized rats: role of 5-HT and LTD4

We have recently demonstrated that tissue resistance increases during the early response (ER) to antigen challenge in sensitized Brown-Norway rats. The purpose of the present study was to investigate the role of the potential ER mediators 5-hydroxytryptamine (5-HT) and leukotriene D4 (LTD4) in the airway and tissue response. We sensitized the rats with ovalbumin (OA) and performed experiments on anesthetized, open-chested, mechanically ventilated [breathing frequency = 1 Hz, tidal volume = 12 ml/kg, positive end-expiratory pressure (PEEP) = 3 cmH2O] animals. We affixed alveolar capsules to the lungs to measure alveolar pressure and calculated the resistance of lung (RL), tissue (Rti), and airway (Raw). To assess the effects of LTD4 and 5-HT, we administered the antagonists methysergide (5-HT antagonist) and MK-571 (LTD4 antagonist) before challenge. To assess lung morphometry during the ER, the lungs of four animals from each group were frozen with liquid nitrogen (PEEP = 3 cmH2O). Airway constriction was assessed by measuring the ratio of the airway lumen to the ideally relaxed airway (Abm/A*bm). Tissue distortion was assessed by measuring the mean linear intercept between alveolar walls (Lm), an atelectasis index (ATI) derived by calculating the ratio of tissue to air space, and SD of the two (SD-Lm and SD-ATI). In all animals receiving OA but no antagonists, an ER was seen (RL, Rti, and Raw = 180.7 +/- 6.1, 155.4 +/- 8.2, and 223.1 +/- 14.0% of baseline, respectively). Methysergide significantly inhibited the ER (RL, Rti, and Raw = 117.0 +/- 5.9, 101.2 +/- 1.6, 133.7 +/- 10.2%, respectively), whereas MK-571 partially reduced the ER (RL, Rti, and Raw = 144.2 +/- 5.6, 132.9 +/- 5.7, and 155.5 +/- 9.2%, respectively). Abm/A*bm was significantly decreased, and SD-Lm and SD-ATI were significantly increased in animals receiving OA alone and in those receiving MK-571 before OA challenge. These data suggest that alterations in both airways and tissues contribute to the ER and that 5-HT and, to a lesser degree, LTD4 are important mediators of the ER in this rat model of extrinsic asthma.