Corticosteroid and long-acting ß-agonist therapy reduces epithelial goblet cell metaplasia

BACKGROUND

Bronchial epithelial goblet cell metaplasia (GCM) with hyperplasia is a prominent feature of asthma, but the effects of treatment with corticosteroids alone or in combination with a long-acting β₂ -adrenergic receptor agonist (LABA) on GCM in the bronchial epithelium are unknown.

OBJECTIVES

To determine whether corticosteroid alone or in combination with a LABA alters protein and gene expression pathways associated with IL-13-induced goblet cell metaplasia.

RESULTS

We evaluated the effects of fluticasone propionate (FP) and of salmeterol (SM), on the response of well-differentiated cultured bronchial epithelial cells to interleukin-13 (IL-13). Outcome measures included gene expression of SPDEF/FOXa2, gene expression and protein production of MUC5AC/MUC5B and morphologic appearance of cultured epithelial cell sheets. We additionally analysed expression of these genes in bronchial epithelial brushings from healthy, steroid-naïve asthmatic and steroid-treated asthmatic subjects. In cultured airway epithelial cells, FP treatment inhibited IL-13-induced suppression of FOXa2 gene expression and up-regulation of SPDEF, alterations in gene and protein measures of MUC5AC and MUC5B and induction of GCM. The addition of SM synergistically modified the effects of FP modestly-only for gel-forming mucin MUC5AC. In bronchial epithelial cells recovered from asthmatic vs healthy human subjects, we found FOXa2 and MUC5B gene expression to be reduced and SPDEF and MUC5AC gene expression to be increased; these alterations were not observed in bronchial epithelial cells recovered after treatment with inhaled corticosteroids.

CONCLUSION AND CLINICAL RELEVANCE

Corticosteroid treatment inhibits IL-13-induced GCM of the airways in asthma, possibly through its effects on SPDEF and FOXa2 regulation of mucin gene expression. These effects are modestly augmented by the addition of a long-acting ß-agonist. As we found evidence for drug treatment counteracting the effects of IL-13 on the epithelium, we conclude that further exploration into the mechanisms by which corticosteroids and long-acting β₂ -adrenergic agonists confer protection against pathologic airway changes is warranted.

Chloride secretion by cultures of pig tracheal gland cells

Malfunction of airway submucosal glands contributes to the pathology of cystic fibrosis (CF), and cell cultures of CF human airway glands show defects in Cl(-) and water transport. Recently, a transgenic pig model of CF (the CF pig) has been developed. Accordingly, we have developed cell cultures of pig airway gland epithelium for use in investigating alterations in gland function in CF. Our cultures form tight junctions (as evidenced by high transepithelial electrical resistance) and show high levels of active anion secretion (measured as amiloride-insensitive short-circuit current). In agreement with recent results on human airway glands, neurohumoral agents that elevate intracellular Ca(2+) potently stimulated anion secretion, while elevation of cAMP was comparatively ineffective. Our cultures express lactoferrin and lysozyme (serous gland cell markers) and MUC5B (the main mucin of airway glands). They are, therefore, potentially useful in determining if CF-related alterations in anion transport result in altered secretion of serous cell antimicrobial agents or mucus.

Differentiated structure and function of primary cultures of monkey oviductal epithelium

We have established well-differentiated, polarized cultures of monkey oviductal epithelium. Oviductal epithelial cells were isolated by protease digestion and plated on collagen-coated, porous cell culture inserts. About 5 d after plating, cells developed detectable transepithelial electrical resistance of up to 2000 Omega.cm(2) (an index of tight junction formation) and transepithelial voltages of up to 20 mV (an index of vectorial transepithelial ion transport). Measurements of short-circuit current in Ussing chambers indicated that active secretion of Cl was the major transepithelial active ion transport process, and that this was stimulated by elevation of either cAMP or Ca(i). Furthermore, estimates of the volume of mucosal liquid were consistent with Cl secretion mediating fluid secretion. Various microscopical methods showed that the cultures were densely ciliated and contained mature secretory cells. Transport across the oviductal epithelium determines the composition of the oviductal fluid, and the study of the relevant transport processes will be greatly enhanced by well-differentiated cultures of oviductal epithelium of the kind established here.

Effects of media on differentiation of cultured human tracheal epithelium

The purpose of the this study was to find media that supported high levels of differentiation in primary cultures of human tracheal epithelium. We tested six previously described, partially defined media and three nondefined media. Cells were grown with an air interface on porous-bottomed inserts, and differentiation was assessed from electrophysiological properties, levels of total protein and deoxyribonucleic acid, and histology. In all media, cells polarized and developed tight junctions, as assessed from transepithelial electrical resistance and were better differentiated at 14 d after plating than at 7 d. The partially defined media described previously by Gray et al. (Am. J. Respir. Cell. Mol. Biol. 14:104-112; 1996) and Matsui et al. (J. Clin. Invest. 102:1125-1131; 1998) and an undefined medium containing Ultroser G serum substitute produced the most highly differentiated epithelial cells, as revealed by a high short-circuit current (I(sc)) and a ciliated, pseudostratified appearance. In other media, cells tended to be either squamous or stratified squamous, with I(sc) levels <25% of those obtained with the three optimal media. Though no key factor in the composition of the partially defined media could be identified, two of the four media with high concentrations of retinoic acid produced good differentiation. In contrast, the two media with the lowest [Ca] (0.11 mM) produced poorly differentiated cells, as did the two partially defined media with low or no retinoic acid concentration.

Effects of growth surface on differentiation of cultures of human tracheal epithelium

Optical measurements from epithelial cells grown on clear solid surfaces (e.g., coverslips, petri dishes) are often compared with other measurements (e.g., short-circuit current; I(sc)) obtained from cells grown on opaque porous surfaces (inserts). However, the relative levels of differentiation of cells grown under the two conditions are usually unknown. To address this issue, we grew primary cultures of human tracheal epithelium on solid surfaces or on porous inserts and compared their total levels of protein and deoxyribonucleic acid, electrical properties in Ussing chambers, and ultrastructure. To measure ion transport across cells grown on solid supports, cells were grown on inserts placed on parafilm. Later, separation of insert from parafilm allowed the cells' I(sc) to be measured in Ussing chambers. Four different media were used. Cells grown in one medium showed very low levels of differentiation on all growth supports. In the other media, growth on inserts markedly enhanced differentiation as compared with solid supports. Baseline I(sc) of cells grown on either clear or opaque inserts was at least 30 times greater than that of cells grown on solid supports, though I(sc) with clear inserts averaged approximately 30% lower than that with opaque inserts. We conclude that though differentiation of cells may vary slightly depending on the insert used, cells on any type of insert are much better differentiated than cells grown on solid surfaces. Thus, it is both possible and desirable to make all functional measurements on cells grown on clear porous supports.

Protease XXIV increases detection of mucin gene expression during in situ hybridization in archival tissue

Digoxigenin-labeled riboprobes of six groups of human mucins were evaluated for sensitivity in archival tissue, using protease XXIV or proteinase K during in situ hybridization. (J Histochem Cytochem 49:923-924, 2001)

Physiology and pathology of tracheobronchial glands

The tracheobronchial glands, composed of mucous and serous secretory cells, provide a mucin-rich, antimicrobial-rich secretion for the conducting airways. The secretory processes of these cells are under complex neurohumoral control. Several diseases demonstrate considerable increases in the volume of secretory glands, the amount of glandular secretions or the character of the secretory product. The role of the tracheobronchial glands in the pathophysiology of chronic bronchitis, asthma and cystic fibrosis is discussed.

Measurement of fibroblast proliferative activity in bronchoalveolar lavage fluid in the analysis of obliterative bronchiolitis among lung transplant recipients

BACKGROUND

Bronchiolitis obliterans occurs in 30% to 80% of lung-transplant recipients and is a direct cause of death in more than 40% of patients with this complication. This study assessed the potential utility of measuring fibroblast-proliferative activity in bronchoalveolar lavage fluid from lung-transplant recipients to better understand the pathogenesis of this process.

METHODS

The capacity of bronchoalveolar lavage fluid obtained from transplant recipients, during routine surveillance bronchoscopy, to stimulate the proliferation of human lung fibroblasts in vitro was assessed retrospectively and compared to that of control subjects. For each recipient, a correlation was made between the fibroblast-proliferative activity in serial lavage samples over time and the other modalities employed for detecting post-transplant complications including spirometry, transbronchial lung biopsy, and high-resolution computed tomography.

RESULTS

There was a significant difference in fibroblast-proliferative activity between volunteer and transplant recipient groups (p = 0.002). Further, for each transplant recipient, the decline in the forced expired flow rate between 25% and 75% of expired volume (FEF(25%-75%)) was correlated with the mean fibroblast-proliferative activity during the period of this study (r = 0.83; p = 0.04).

CONCLUSIONS

A sustained increase in fibroblast-proliferative activity in lavage supernatant precedes both histologic and physiologic evidence of bronchiolitis obliterans. Relative to an increase in fibroblast-proliferative activity or abnormalities in FEF25%-75%, a decrease in forced expiratory volume in 1 second is a late finding.

Restoration of cyclic adenosine monophosphate-stimulated chloride channel activity in human cystic fibrosis tracheobronchial submucosal gland cells by adenovirus-mediated and cationic lipid-mediated gene transfer

In human airways, the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) is predominantly expressed in serous cells of the tracheobronchial glands. Despite considerable evidence that submucosal glands are important contributors to the pathophysiology of CF lung disease, most attempts at CFTR gene transfer have primarily targeted airway surface epithelial cells. In this study, we systematically evaluated CFTR gene transfer into cultures of immortalized CF human tracheobronchial submucosal gland (6CFSMEO) cells using adenovirus and cationic lipid vectors. We found that the efficiency of adenovirus-mediated gene transfer was comparable in 6CFSMEO and CFT1 cells (a surface airway epithelial cell line isolated from a subject with CF). So was the ranking order of adenovirus vectors containing different enhancers/promoters (CMV >> E1a approximately phosphoglycerokinase), as determined by both X-Gal staining and quantitative measurement of beta-galactosidase activity. Further, we provide the first demonstration that cationic lipids mediate efficient gene transfer into 6CFSMEO cells in vitro. The transfection efficiency at optimal conditions was higher in 6CFSMEO than in CFT1 cells. Finally, either infection with adenoviral vectors or transfection with cationic lipid:plasmid DNA complexes encoding CFTR significantly increased chloride (Cl-) permeability, as assessed using the 6-methoxy-N-(3-sulfopropyl)-quinolinium (SPQ) fluorescence assay, indicating restoration of functional CFTR Cl- channel activity. These data show that although the mechanisms of transfection may be different between the two cell types, 6CFSMEO cells are as susceptible as CFT1 cells to transfection by adenoviral and cationic-lipid gene transfer vectors.

Alveolar epithelial fluid transport capacity in reperfusion lung injury after lung transplantation

Reperfusion lung injury is an important cause of morbidity and mortality after orthotopic lung transplantation. The purpose of this study was to investigate the function of the alveolar epithelium in the setting of reperfusion lung injury. Simultaneous samples of pulmonary edema fluid and plasma were collected from eight patients with severe post-transplantation reperfusion edema. The edema fluid to plasma protein ratio was measured, an indicator of alveolar-capillary barrier permeability. The initial edema fluid to plasma protein ratio was > 0.75 in six of eight patients, confirming the presence of increased permeability of the alveolar-capillary barrier. Graft ischemic time was positively correlated with the degree of permeability (r = 0.77, p < 0.05). In four of six patients with serial samples, there was a high rate of alveolar fluid clearance (19 +/- 9%/h, mean +/- SD). Alveolar fluid clearance was calculated from serial samples in six patients. Intact alveolar fluid clearance correlated with less histologic injury, rapid resolution of hypoxemia, and more rapid resolution of radiographic infiltrates. The two patients with no net alveolar fluid clearance had persistent hypoxemia and more severe histologic injury. This study provides the first direct evidence that increased permeability to protein is the usual cause of reperfusion edema after lung transplantation, with longer ischemic times associated with greater permeability to protein in the transplanted lung. The high rates of alveolar fluid clearance indicate that the fluid transport capacity of the alveolar epithelium may be well preserved in the allograft despite reperfusion lung injury. The ability to reabsorb fluid from the alveolar space was a marker of less severe reperfusion injury, whereas the degree of alveolar-capillary barrier permeability to protein was not. Measurement of alveolar fluid clearance may be useful to assess the severity of reperfusion lung injury and to predict outcome when pulmonary edema develops after lung transplantation.

Differential regulation of centrin genes during ciliogenesis in human tracheal epithelial cells

Centrins are small calcium-binding proteins found in a variety of cell types, often in association with microtubule-organizing centers. Here we present results regarding the expression of centrins during the in vitro differentiation of human tracheal epithelial cells. When grown at an air-liquid interface, these cells differentiate into mucus-secreting cells or undergo ciliogenesis. In immunofluorescence and immunoelectron microscopy experiments, an anti-centrin antibody stained exclusively the basal bodies of the ciliated cells. There was no staining over the axonemes or the striated rootlets. Northern blots and RT-PCR analysis of the three known human centrin genes showed that these genes have distinct patterns of expression during the growth and differentiation of human tracheal epithelial cells. Centrin-1 is never transcribed. Centrin-2 mRNA is present at all times, and its concentration increases when ciliogenesis occurs. Centrin-3 mRNA is found at a constant level throughout the entire process. This differential regulation suggests that centrins are not interchangeable but instead have unique functions.

Fluid transport across cultures of human tracheal glands is altered in cystic fibrosis

1. There is evidence that defective submucosal gland secretion contributes to the airway pathology of cystic fibrosis (CF). Using a capacitance probe technique, we have compared fluid transport across submucosal gland cultures from individuals with and without CF. 2. Under baseline conditions, approximately 60% of non-CF cultures secreted fluid; the rest absorbed. In secreting tissues, amiloride increased secretion, whereas in absorbing tissues it reduced or reversed absorption. 5-Nitro-2(3-phenylpropylamino)-benzoate (NPPB) a blocker of the CF transmembrane conductance regulator (CFTR), converted secretion to absorption. Thus, the direction and magnitude of baseline fluid movement depended on a balance between active absorption of Na+ and cAMP-dependent secretion of Cl-. 3. 8-(4-Chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (CPT-cAMP), methacholine and luminal uridine 5'-triphosphate (UTP) all induced or increased fluid secretion across non-CF cultures. Results with NPPB and with 4,4'-diisothiocyanatostilbene-2,2'-disulphonate (DIDS), a blocker of Ca(2+)-activated Cl- channels, suggested that fluid secretion induced by CPT-cAMP was mediated primarily by CFTR; UTP acted entirely via Ca(2+)-activated Cl- channels, and methacholine activated both pathways. 4. All CF cultures showed baseline fluid absorption, which was abolished by amiloride. 5. CF cultures showed a normal secretory response to UTP, a reduced response to methacholine, and no response to CPT-cAMP. 6. Thus, the absorptive processes of airway glands are retained in CF, but the cAMP-dependent secretory process is lost. This would markedly reduce the water content of gland secretions. The resulting change in viscosity would contribute to the accumulation of airway mucus which is characteristic of this disease.

Fetal congenital cystic adenomatoid malformations of the lung: a clinicopathologic study of eleven cases

We describe the pathological examination of 11 cases of fetal congenital cystic adenomatoid malformation of the lung. All patients were treated in utero between 21 and 27 weeks of gestation with either lobectomy or placement of a thoracoamniotic shunt. Ten cases involved a single lobe, and one case involved two lobes. The lesions contained both solid and cystic areas. On the basis of microscopic appearances, we separated the malformations into two distinct types. The first type consisted of seven cases showing scattered bronchiole-like dilated spaces lined by pseudostratified ciliated epithelium with intervening tightly packed small tubules lined by columnar cells with subnuclear vacuoles. This pattern superficially resembled the pseudoglandular period of lung development. The remaining four cases were of the other histologic type. They contained scattered bronchiole-like structures with intervening irregularly branching glands lined by cuboidal epithelium within loose mesenchymal stroma. This pattern superficially resembled the canalicular period of lung development. We observed that the malformations contained cysts of various sizes and that cyst size varied widely within a single lesion. Moreover, predominantly cystic and predominantly solid lesions could not be separated histologically. Thus, we identify two patterns of fetal congenital cystic adenomatoid malformations, pseudoglandular and canalicular, the clinical significance of which is yet to be determined.

Role of CFTR in chloride secretion across human tracheal epithelium

We have tested two hypotheses: 1) the cystic fibrosis transmembrane conductance regulator (CFTR) represents the predominant Cl conductance in the apical membrane of human tracheal epithelium, and 2) CFTR in this tissue is close to maximally activated under baseline conditions. In support of the first hypothesis, we found 1) when the level of differentiation of cultures was varied by varying the culture conditions, there was a significant positive correlation between the levels of CFTR and the magnitude of mediator-induced Cl secretion. 2) Amiloride-insensitive baseline short-circuit current (Isc) and mediator-induced increases in Isc were inhibited by diphenylamine-2-carboxylic acid (DPAC) but not by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), a pharmacology consistent with passage of apical membrane Cl current through CFTR; Ca-activated Cl channels are inhibited by DIDS but not by DPAC. 3) Raising temperature from 22 degrees to 37 degrees C increased 125I efflux, and this increase was inhibited by DPAC and blockers of protein kinase A, but not by DIDS or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester. In support of the second hypothesis, we have earlier shown [M. Yamaya, W.E. Finkbeiner, S.Y. Chun, and J.H. Widdicombe. Am. J. Physiol. 262 (Lung Cell. Mol. Physiol. 6): L713-L724, 1992] that adenosine 3',5'-cyclic monophosphate (cAMP)-elevating agents are essentially without effect on Isc across primary cultures of human tracheal epithelium. Here, we further show that these agents are also usually without effect on 125I efflux; the mean increase in efflux in response to elevating cAMP was approximately 20% that of raising temperature from 22 degrees to 37 degrees C.

Expression of airway secretory epithelial functions by lung carcinoma cells

We examined 12 non-small cell lung carcinoma cell lines for expression of airway goblet, serous, and mucous cell characteristics. The cells expressed some ultrastructural traits of secretory epithelial cells but none contained secretory granules typical of the airway secretory cells. Using immunocytochemistry and cell-specific monoclonal antibodies, we identified heterogeneous expression of goblet, mucous, and serous cell markers among the cell lines. After metabolic radiolabeling, cells incorporated isotope into high molecular weight material. Incubation of pulse-radiolabeled cells with a number of known mucus secretogogues revealed that 5 of the 12 cell lines released radiolabeled material in response to the agonists. However, in each cell line only one of the receptor-activated pathways tested was intact. Although we did not identify a single cell line expressing a phenotype similar to normal airway secretory cells, particular functions retained by some of these cell lines may make them useful for specific studies of mucus production or secretion.

Sudden cardiac death and polymorphous ventricular tachycardia in patients with normal QT intervals and normal systolic cardiac function

This study delineates the clinical spectrum of 15 patients with polymorphic ventricular tachycardia and normal QT intervals in the absence of apparent structural heart disease, adverse drug effects, or electrolyte disturbances. Patients presented with either palpitations (n = 2), presyncope (n = 5), syncope (n = 4), no symptoms (n = 1), or aborted sudden death (n = 3). Mean age was 41 years (range 20 to 64), and mean follow-up 38 months (range 4 to 109). Left ventricular function was normal as determined by either echocardiogram (n = 9) or left ventriculography (n = 9). Episodes of polymorphic ventricular tachycardia (VT) were analyzed in terms of the preceding interval, and the relation of the initiating coupling interval to the QT interval (coupling interval/QT interval = polymorphic VT index). The mean QT for the group as a whole was 0.41 +/- 0.02 second. Patients could be separated into 3 distinct groups. Four patients had polymorphic VT reproducibly induced by exercise and initiated by late-coupled beats (mean polymorphic VT index 1.27 +/- 0.21). Isoproterenol induced polymorphic VT in 3 of 4 patients, and all 4 responded to chronic beta blockade. Two patients had polymorphic VT during episodes of coronary artery spasm, and both responded to calcium channel blockade. Polymorphic VT unrelated to exertion or coronary vasospasm occurred in 9 patients. Tachycardia onset was initiated by closely coupled beats (mean polymorphic VT index 0.95 +/- 0.16), and was preceded by a pause in 4 patients, and no pause in 5 patients. Sudden death occurred in 5 of 9 patients with the shortest polymorphic VT indexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Culture and transformation of human airway epithelial cells

The culture of human airway epithelial cells has played an important role in advancing our understanding of the metabolic and molecular mechanisms underlying normal function and disease pathology of airway epithelial cells. Recent advances in culturing primary epithelial cells and the development of transformed airway epithelial cell lines have been particularly important in enhancing our understanding of the pathology associated with cystic fibrosis and lung cancer. The establishment of conditions that enhance the proliferative capacity of airway epithelial cells in primary culture was the first technical hurdle overcome in the development of in vitro culture systems. Research is now being geared toward the development of cell culture conditions that facilitate the expression in culture of the differentiated characteristics found in the native epithelium. Aside from the advances that have been made in defining the growth media and extracellular matrixes that enhance the expression of differentiated features, the use of an air-liquid interface has been a significant advance in the culture of airway epithelial cells. The implementation of the in vitro cell culture systems that have now been established and the research into optimizing the conditions for the growth of airway epithelial cells have been and will continue to be essential in the development of therapies for airway disease.

Do patients with primary pulmonary hypertension develop extensive central thrombi?

BACKGROUND

Distinguishing chronic major vessel thromboembolic pulmonary hypertension from primary pulmonary hypertension is critical because the treatment options differ markedly. Surgical thromboendarterectomy is potentially curative in the former condition, whereas oxygen, vasodilators, perhaps anticoagulation, and lung transplantation are the options for the latter. The development of large thrombi in the main, right, or left pulmonary arteries has not been previously described in patients with primary pulmonary hypertension.

METHODS AND RESULTS

Three pulmonary hypertensive patients with massive thrombi in the central pulmonary arteries are described. The data indicate that the large central thrombi in these three patients were not hemodynamically significant. In none did perfusion lung scans demonstrate segmental or larger defects.

CONCLUSIONS

Large central thrombi can develop in patients with primary pulmonary hypertension. Perfusion lung scans that do not demonstrate segmental or larger defects should alert physicians to this possibility. Chest computed tomography and other studies identifying such thrombi are not adequate in distinguishing such a development from operable chronic major vessel thromboembolic hypertension. Careful review of lobar and segmental artery findings and the pulmonary angiogram, angioscopy, and cardiac catheterization data demonstrating the hemodynamic significance (or lack thereof) of these thrombi are essential in making this important distinction. Furthermore, these observations may constitute an additional indication for anticoagulant therapy in primary pulmonary hypertension.

Chloride secretion and function of serous and mucous cells of human airway glands

Cells from the acini of human tracheal glands were grown in culture to produce confluent cell sheets of mucous or mixed seromucous phenotype. Levels of mediator-induced Cl secretion in mucous cells were 2-18% those of seromucous cells. Levels of the cystic fibrosis transmembrane conductance regulator (an apical membrane Cl channel) were also much less in mucous than in seromucous cells. These results suggest that serous cells are more important than mucous cells in providing the fluid component of gland secretions.

Effects of long-term right ventricular apical pacing on left ventricular perfusion, innervation, function and histology

OBJECTIVES

The purpose of this study was to better understand the effects of long-term right ventricular pacing on left ventricular perfusion, innervation, function and histology.

BACKGROUND

Long-term right ventricular apical pacing is associated with increased congestive heart failure and mortality compared with atrial pacing. The exact mechanism for these changes is unknown. In this study, left ventricular perfusion, sympathetic innervation, function and histologic appearance after long-term pacing were studied in dogs in an attempt to see whether basic changes might be present that might ultimately be associated with the adverse clinical outcome.

METHODS

A total of 24 dogs were studied. Sixteen underwent radiofrequency ablation of the atrioventricular (AV) junction to produce complete AV block. Seven of these underwent long-term pacing from the right ventricular apex (ventricular paced group), and nine had atrial and right ventricular apical pacing with AV synchrony (dual-chamber paced group). A control group of eight dogs had sham ablations with normal AV conduction. These dogs had atrial pacing only. Regional perfusion and sympathetic innervation were studied in all dogs by imaging with thallium-201 and [I123]metaiodobenzylguanidine, respectively. The degree of innervation was also determined by assay of tissue norepinephrine levels. Left ventricular function was assessed by radionuclide ventriculography. Cardiac histology was studied with both light and electron microscopy.

RESULTS

Mismatching of perfusion and innervation in the ventricular paced group was noted, with perfusion abnormalities of both the septum and free wall. Regional [I123]metaiodobenzylguanidine distribution was homogeneous. Tissue norepinephrine levels were elevated in both the ventricular and dual-chamber paced groups compared with the control group. No light or electron microscopic findings were noted in any groups. In the dual-chamber paced group, diastolic dysfunction was noted, with normal systolic function.

CONCLUSIONS

Ventricular pacing resulted in regional changes in tissue perfusion and heterogeneity between perfusion and sympathetic innervation. Both ventricular and dual-chamber pacing were associated with an increase in tissue catecholamine activity. The abnormal activation of the ventricles via right ventricular apical pacing may result in multiple abnormalities of cardiac function, which may ultimately affect clinical outcome.

Use of mucin antibodies and cDNA probes to quantify hypersecretion in vivo in human airways

Mucus hypersecretion is a prominent feature of the airway's response to injury. The ability to quantitatively detect mucin and mucin mRNA in vivo in human airways would facilitate the determination of safe exposure levels to various air pollutants and the identification of drugs capable of attenuating mucus hypersecretion. To this end, we have developed two assays: an enzyme-linked immunosorbent assay (ELISA) quantifying mucin-like molecules and a polymerase chain reaction (PCR)-based assay quantifying mucin mRNA. These tests are performed on bronchial lavage fluid and epithelial cells brushed from the surfaces of human airways at bronchoscopy. The PCR data are normalized to eliminate potentially confounding effects of nonepithelial cells in the samples. In a study of six smokers and six nonsmokers, the ELISA detected significantly more mucin-like material in the airways of the smokers than of the nonsmokers. The median mucin concentration for the smokers was 52.2 micrograms/ml (range, 16.3 to 4,860.0), whereas that for the nonsmokers was 12.7 micrograms/ml (range, 4.5 to 22.9). The difference between smokers and nonsmokers was statistically significant (P < or = 0.01). The PCR-based test showed a trend for RNA samples from smokers to be enriched (vis-à-vis nonsmokers) in mucin mRNA.

Calu-3: a human airway epithelial cell line that shows cAMP-dependent Cl- secretion

Of 12 cell lines derived from human lung cancers, only Calu-3 cells showed high transepithelial resistance (Rte) and increases in short-circuit current (Isc) in response to mediators. Calu-3 cells formed polarized monolayers with tight junctions and Rte of approximately 100 omega.cm2. Baseline Isc was approximately 35 microA/cm2 and was increased by approximately 75 microA/cm2 on elevation of intracellular adenosine 3',5'-cyclic monophosphate (cAMP) by isoproterenol. Flux studies showed that the increase in Isc was due to Cl- secretion. Forskolin and permeant analogues of cAMP also increased Isc. Consistent with the presence of cAMP-dependent Cl- secretion, immunoprecipitation demonstrated the presence of the cystic fibrosis transmembrane conductance regulator (CFTR). Bradykinin, methacholine, trypsin, and histamine all transiently (15-30 s) elevated Isc, probably by increasing intracellular Ca concentration. Experiments in which the basolateral membrane was permeabilized with nystatin indicated that CFTR was substantially activated under baseline conditions and that Ca-activated Cl- channels were absent from the apical membrane. We anticipate that Calu-3 cells will prove useful in the study of Cl- secretion and other functions of human airway epithelial cells.

CFTR in Calu-3 human airway cells: channel properties and role in cAMP-activated Cl- conductance

Calu-3, a cell line derived from a lung adenocarcinoma, forms tight junctions, expresses cystic fibrosis transmembrane conductance regulator (CFTR), and secretes Cl- in response to adenosine 3',5'-cyclic monophosphate (cAMP)-elevating agents. Anion conductance of Calu-3 cells was assessed with isotopic flux and patch-clamp methods at 22 degrees C. Iodide efflux was increased by cAMP-elevating agents and brief trypsin treatment. A 7.1 +/- 0.4-pS voltage-independent Cl- channel with linear current-voltage relation was the most common channel observed in cell-attached recordings and was identified as CFTR on the basis of shared features with recombinant CFTR. In unstimulated cells, the mean minimum number of active CFTR channels per patch was 1 +/- 1 (n = 12), increasing to 6 +/- 8 (n = 40) after stimulation with cAMP-elevating agents or after brief trypsin treatment. Channel closure after excision was biexponential with tau 1 approximately 4 s and tau 2 approximately 79 s; typically channels were open continuously until closing permanently. In 11 of 12 excised patches, channels were reactivated by exposure to cAMP-dependent protein kinase (PKA) plus ATP. Efficacy of reactivation was inversely related to the duration from excision to addition of PKA. Channels were blocked by 20-40 microM 5-nitro-2-(3-phenylpropylamino)benzoate on cytosolic but not external side. Active CFTR channels were recorded in 83% of total patches. Other types of Cl- channels were observed in 5 of 52 (10%) cell-attached patches and in 17 of 34 (50%) excised patches, including an outwardly rectifying channel in 2 patches. CFTR channels are the predominant pathway for cAMP-stimulated Cl- conductance in Calu-3 cells; the long open times in the absence of ATP are not explained by present models of CFTR activation.

Extrarenal tissue distribution of CHIP28 water channels by in situ hybridization and antibody staining

This study is an extension of in situ hybridization experiments showing expression of mRNA encoding CHIP28 in selected epithelial or endothelia in spleen, colon, lung, and eye (H. Hasegawa, R. Zhang, A. Dohrman, and A. S. Verkman. Am. J. Physiol. 264 (Cell Physiol. 33): C237-C245, 1993). Additional tissues from rat were screened by in situ hybridization, and tissues from rat and humans were stained with a polyclonal anti-CHIP28 antibody. Northern blot showed the 2.8-kilobase mRNA encoding CHIP28 in kidney, lung, and heart. In situ hybridization showed strong hybridization in epithelial cells in choroid plexus, iris, ciliary body, and lens and in epithelial and subepithelial layers of trachea. Except for colonic crypts, specific hybridization was not observed in the gastrointestinal tract, liver, thyroid gland, and muscle. Immunoblot of tissues from exsanguinated rats showed immunoreactive CHIP28 protein in kidney, lung, trachea, and heart. In fixed frozen rat and/or human tissues, the anti-CHIP28 antibody stained epithelial cells in kidney proximal tubule and thin limb of Henle, lung alveolus, bronchial mucosa and glands, choroid plexus, ciliary body, iris, lens surface, colonic crypt, sweat gland, pancreatic acini, gallbladder epithelium, and placental syncytial trophoblast cells. Endothelial cells were stained in many tissues. These studies indicate a wide and selective CHIP28 tissue distribution, suggesting an important role for CHIP28 in fluid transport. The absence of CHIP28 in many nonrenal membranes believed to be water permeable suggests the existence of non-CHIP28 water transporters.

CFTR expression and chloride secretion in polarized immortal human bronchial epithelial cells

A major limitation in the study of vectorial ion transport, secretion, and differentiated function in the human airway epithelium has been the lack of suitable cell culture systems. Progress in this direction has been made through the transformation of primary cultured epithelial cells. However, these transformants tend to lose differentiated properties with increasing serial passage, particularly following crisis. The successful establishment of a postcrisis SV40 large T-antigen transformed epithelial cell line derived from human bronchial epithelium is described. This cell line, 16HBE14o-, retains differentiated epithelial morphology and functions. Cell cultures show the presence of tight junctions and cilia, and monolayers generate transepithelial resistance, as measured in Ussing chambers, and retain beta-adrenergic stimulation of cAMP-dependent chloride ion transport, measured either by 36Cl- efflux or as short-circuit current in Ussing chambers. The cells also increase chloride transport in response to bradykinin or calcium ionophore. In addition, 16HBE14o- cells express levels of both the cystic fibrosis transmembrane conductance regulator (CFTR) mRNA and protein readily detectable by Northern and Western hybridization analysis, respectively. These cells provide a valuable resource for studying the modulation of CFTR and its role in regulation of chloride ion transport in human airway epithelium as well as other aspects of human airway cell biology.

Reverse transcription-polymerase chain reaction (RT-PCR) phenotypic analysis of cell cultures of human tracheal epithelium, tracheobronchial glands, and lung carcinomas

In order to identify expression of RNA transcripts for a number of important tracheobronchial cell products and molecules, we developed simple reverse transcription-polymerase chain reaction (RT-PCR) assays. Assays included the RNA for two apomucins (MUC1 and MUC2), secretory component, secretory leukocyte inhibitor protein, lysozyme, lactoferrin, 15-lipoxygenase, and the cystic fibrosis transmembrane conductance regulator. We tested RNA of normal and neoplastic origin. Sources of normal tissue included human tracheal surface epithelial cells and tracheobronchial submucosal tissues, acutely isolated human tracheal surface epithelial and tracheobronchial gland acini, and confluent cultures of human tracheal epithelial and tracheobronchial gland cells. Sources of neoplastic tissue included cell lines of non-small cell carcinomas of the lung. RNA expression was correlated with protein expression as assessed by immunocytochemistry. Tracheal surface epithelial tissues, isolated cells and cultures, and tracheobronchial submucosal tissues expressed RNA transcripts for all of the RNA transcripts assayed. Isolated gland acini and cultured gland cells expressed all RNA transcripts except 15-lipoxygenase. Expression of RNA transcripts by non-small cell lung carcinomas was heterogeneous and not necessarily influenced by histopathologic type. In most instances, RNA expression predicted expression of immunocytochemically detectable protein. These RT-PCR assays are useful for characterizing the molecular phenotype of cell cultures derived from normal or neoplastic airway epithelium and for establishing the potential of cultured cells for functional studies.

Ozone-induced airway inflammation in human subjects as determined by airway lavage and biopsy

Ozone (O3) is a major constituent of urban air pollution. The acute effects of the inhalation of O3 at ambient or near-ambient concentrations on bronchoalveolar lavage (BAL) end points consistent with a distal lung inflammatory response have been well documented in human subjects. Animal toxicologic studies have shown that the airway is also a major site of O3-induced injury and inflammation. To date, no studies have confirmed this finding in human subjects. Effects of O3 on the proximal airways are not adequately studied by BAL, which is primarily influenced by events occurring in the terminal bronchioles and alveoli. We hypothesized that O3 causes injury and inflammation in the airways in addition to that previously documented to occur in the distal lung. We performed isolated lavage of the left mainstem bronchus and forceps biopsy of the bronchial mucosa in a group of 14 healthy, athletic subjects 18 h after exposure to 0.20 ppm O3 for 4 h during moderate exercise in order to assess this possibility. We followed an identical protocol in a similar group of 12 subjects exposed to filtered air. The mean (SD) total cell count and the lactate dehydrogenase (LDH) concentration in the isolated airway lavage were significantly greater after O3 than after air, 13.9 (20.5) versus 4.9 (5.4) cells/ml x 10(4) and 18.9 (11.2) versus 9.6 (9.0) U/L, respectively. Morphometry (2,070 neutrophils/cm2 of tissue for O3 and 330 neutrophils/cm2 of tissue for air) demonstrated that O3 exposure induced an acute inflammatory cell influx into the airway.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered fluid transport across airway epithelium in cystic fibrosis

In cystic fibrosis (CF), absence or dysfunction of a phosphorylation-regulated chloride channel [CF transmembrane conductance regulator (CFTR)] leads to the loss or reduction of chloride secretion into the airways. Active sodium absorption is also increased in CF, and both of these ion transport changes could alter fluid transport across the airways. Under baseline conditions, cultured human airway epithelia from normal individuals absorbed fluid, and this absorption was increased in epithelia from patients with CF. In normal and CF epithelial cultures fluid absorption was inhibited by amiloride. Adenosine 3',5'-monophosphate stimulated fluid secretion in normal epithelial cultures but not in cultures from individuals with CF. In contrast, fluid secretion induced by nucleotide triphosphates (uridine triphosphate or adenosine triphosphate) was unaltered in cultures of epithelia from patients with CF, suggesting an approach to the treatment of CF.

Effects of nitric acid gas alone or in combination with ozone on healthy volunteers

Nitric acid (HNO3) is the most prevalent acid air pollutant in the western United States and has the potential to cause adverse respiratory effects through both acidification and oxidation reactions. To study this potential, we measured physiologic (specific airway resistance, SRaw, FEV1, and FVC) and bronchoalveolar lavage (total and differential cell counts, LDH, fibronectin, and total protein) end points in a group of 10 healthy, athletic subjects who were exposed to 500 micrograms/m3 of HNO3 gas or filtered air for 4 h during moderate exercise (ventilatory rate, 40 L/min) and underwent bronchoscopy 18 h later. Under an identical protocol, 10 healthy subjects were exposed to 500 micrograms/m3 of HNO3 gas plus 0.20 ppm ozone (O3) or 0.20 ppm O3 alone to determine if HNO3 might enhance the toxicity of O3. In addition to bronchoalveolar lavage (BAL), we employed the techniques of isolated left mainstem bronchial lavage and bronchial biopsy to determine if proximal airway injury was caused by pollutant exposure and whether there was any correlation with the degree of distal lung injury as assessed by BAL. We found no significant differences in pulmonary function tests or in the cellular or biochemical constituents in either the BAL or the left mainstem lavage fluids between the HNO3 and the air exposures. Similarly, there were no differences in these end points between the HNO3/O3 and the O3 exposures. Furthermore, there were no significant differences in the bronchial biopsy specimens between the HNO3 and air exposures or between the HNO3/O3 and O3 exposures.(ABSTRACT TRUNCATED AT 250 WORDS)

Are patients with neoplasia at an increased risk for cardiac myxomas?

A case-control study was undertaken to assess whether a significant association exists between the presence of a neoplasm or malignancy and the presence of a cardiac myxoma. We identified 13 patients seen at our institution between 1935 and 1990 whose autopsies revealed a cardiac myxoma that was undetected during the patient's lifetime. For each patient four control subjects were selected among the autopsied patients who had never had a cardiac myxoma; these were matched for age at death, gender, and year of autopsy. The institutional medical records and autopsy reports revealed that 46% of the patients and 65% of their controls had a neoplasm diagnosed prior to or at autopsy. The estimated odds ratio was 0.34 (95% confidence interval, 0.05 to 1.84). There was insufficient evidence to conclude that an association exists between the presence of a neoplasm and the presence of a cardiac myxoma (P = .2722).

Calcium-dependent chloride secretion across cultures of human tracheal surface epithelium and glands

Surface epithelium and gland cells from human trachea were cultured on porous-bottom inserts and loaded with fura 2 to permit measurement of the intracellular calcium concentration ([Ca2+]i). Short-circuit current (Isc), an index of transepithelial active ion transport, was measured on cells from the same cultures. Surface epithelial [Ca2+]i of 82 +/- 15 nM was increased transiently by isoproterenol, histamine, and bradykinin with maximal increases of 88 +/- 17, 480 +/- 149, and 978 +/- 214 nM (n = 15), respectively. Baseline [Ca2+]i in cultured gland cells of 68 +/- 11 nM was increased transiently by isoproterenol, histamine, methacholine, and bradykinin with maximal increases of 105 +/- 19, 233 +/- 47, 327 +/- 121, and 634 +/- 151 nM (n = 17-21), respectively. In both cell types, mediators that increased [Ca2+]i also increased Isc with a time course identical to the increase in [Ca2+]i. Pretreatment with the calcium chelator, 1,2-bis-(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid, acetoxymethyl ester (BAPTA-AM), had no effect on basal Isc or transepithelial resistance but markedly inhibited both the Isc and [Ca2+]i responses to agonists. Forskolin (10(-5) M), 3-isobutyl-1-methylxanthine (10(-3) M), dibutyryl adenosine 3',5'-cyclic monophosphate (10(-3) M), and 8-(4-chlorophenylthio)-cAMP (10(-3) M) had no or only trivial effects on Isc and [Ca2+]i. We suggest that mediators increase Isc across human airway epithelium by activating Ca-dependent basolateral K channels, resulting in hyperpolarization and an increased driving force for Cl exit through apical membrane Cl channels.

Markers of mucus secretion and DNA levels in induced sputum from asthmatic and from healthy subjects

To determine whether markers of mucus secretion can be quantified in airway lining fluid from asthmatic and from healthy subjects, we measured levels of a mucin-like glycoprotein (MLG) and lactoferrin in sputum induced by inhalation of hypertonic (3%) saline in 18 asthmatic and in 10 healthy subjects. Because DNA, like mucin, contributes to the viscosity of airway secretions, we also measured DNA levels in the induced sputum samples. To control for the presence of saliva in sputum, we also analyzed saliva samples from all subjects. The entire sputum sample and the saliva sample were reduced using dithiotreitol, and biochemical analysis was performed on supernatants obtained after centrifugation. We found that induced sputum from asthmatic subjects had higher levels of MLG [2,574.4 +/- 907.8 (mean +/- SEM) versus 562.2 +/- 90.5 micrograms/ml, p < 0.007] and DNA (7.1 +/- 1.6 versus 3.6 +/- 0.6 micrograms/ml, p < 0.05), but the difference in lactoferrin levels failed to reach statistical significance. However, in the subgroup of asthmatic subjects who gave a history of sputum production (n = 9), lactoferrin levels were higher than in the healthy control subjects (118.9 +/- 46.3 versus 35.2 +/- 6.5 micrograms/ml, p < 0.05). The very low levels of MLG, DNA, and lactoferrin measured in saliva were not significantly different in asthmatic subjects from those in healthy subjects. We conclude that measurement of markers of mucus secretion in induced sputum is feasible in asthmatic and healthy subjects, and it reveals abnormally high markers of mucus secretion in subjects with stable asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Cultures of bovine tracheal epithelium with differentiated ultrastructure and ion transport

Tracheal epithelial cells were grown on Nuclepore filters coated with human placental collagen. When grown immersed in medium containing fetal bovine serum, cells displayed an undifferentiated ultrastructure (no cilia and a cell height of approximately 10 microns). Short-circuit current (Isc) was approximately 1/10 that of the native epithelium. By contrast, when grown in hormonally defined, serum-free medium with an air interface, cells showed Isc equal to or greater than the original tissue, possessed cilia, and had a cell height of approximately 50 microns. Responses in Isc to mediators were similar to those of the original tissue, but differed from those of dog or human tracheal epithelium. Given the ready availability and low cost of the native tissues, bovine tracheal cultures grown in serum-free medium with an air interface should prove useful in studies of airway epithelial physiology.

Ablation of ventricular tachycardia using multiple sequential transcatheter application of radiofrequency energy

Multiple sequential radiofrequency energy was applied in the left and right ventricles of 24 dogs to produce large ablated areas limited to endocardial and subendocardial regions. Endocardial ablation was performed in nine dogs with normal ventricles and 15 that had survived remote myocardial infarcts, three with inducible sustained monomorphic ventricular tachycardia. A quadripolar catheter was positioned either at the site of earliest ventricular activation during induced monomorphic ventricular tachycardia or at circumscribed areas of the left ventricle. Radiofrequency energy was delivered between two adjacent poles of the catheter, successively applying radiofrequency energy to the distal, middle, and proximal electrode pairs; this was repeated 9 to 11 times with the catheter in a slightly different position. A cumulative energy of 9,688 +/- 4,191 joules resulted in an ablated endocardial/subendocardial surface area of 4.7 +/- 2.2 cm2 (range 2.4-10 cm2, maximum depth 4 mm). Sustained tachycardia was not inducible by aggressive programmed ventricular stimulation in the dogs with previously inducible tachycardia, indicating successful ablation of the tachycardia foci. Only seven normal dogs were available for electrophysiological studies; three were used in acute and four in chronic studies. Ventricular tachycardia was not induced in the remaining dogs either before or after radiofrequency ablation, indicating the lack of an arrhythmogenic effect of this method. Histologic examination was performed in all nine normal dogs (five were sacrificed for acute pathological examination) as well as in the 15 with myocardial infarction. The late pathological examination of the radiofrequency lesion in these 19 animals showed homogeneous areas of coagulation necrosis and endocardial proliferation. Thus, this modified technique of radiofrequency ablation produced large homogeneous endocardial/subendocardial scars suitable for treating ventricular tachycardia and showed no evidence of an arrhythmogenic influence.

Characterization of immortal cystic fibrosis tracheobronchial gland epithelial cells

Tracheobronchial glands were isolated and cultured from a patient with cystic fibrosis (CF). Cultured epithelial cells were transformed with pSVori-. All transformed cell lines express cytokeratin filaments and at early passages express the junctional complex molecule cell CAM 120/80, indicating their epithelial origin. Several gland cell lines express antigens that localize to secretory cells in vivo. Cl- transport measured by 36Cl efflux shows that CF gland epithelial cells, like CF surface airway and nasal polyp epithelial cells, are unable to respond to increases in intracellular cAMP. However, they do produce an increase in intracellular cAMP after treatment with isoproterenol or forskolin. One CF gland cell line shows increased intracellular calcium in response to a number of agents and increased Cl- efflux comparable to that observed in a non-CF airway surface epithelial cell line after addition of calcium ionophore. All cell lines express CF transmembrane conductance regulator mRNA, as measured by PCR amplification of first-strand cDNA. The CF tracheobronchial gland cell lines described here are compound heterozygotes, having a single copy of the delta F508 mutation.

Differentiated structure and function of cultures from human tracheal epithelium

Here we describe the conditions which allow cultured human tracheal epithelial cells to retain the ion transport properties and ultrastructure of the original tissue. The order of potency of growth supports and media additives in elevating baseline short-circuit current (Isc) and responses to mediators were vitrogen gel (VIT) greater than extracellular matrix from bovine corneal endothelial cells (ECM) greater than human placental collagen (HPC), and 2% Ultroser G serum substitute (USG) greater than 5% fetal calf serum (FCS) greater than defined growth factors (GF). For all combinations of medium and growth supports, an air interface (AIR) gave better electrical properties than immersion feeding (IMM). As opposed to our earlier conditions (HPC/FCS/IMM), the best new combination (VIT/USG/AIR) produced higher baseline Isc (58.0 +/- 10.6 vs. 5.1 +/- 1.0 microA/cm2) and increased Isc responses to isoproterenol (6.1 +/- 1.5 vs. 0.8 +/- 0.3 microA/cm2) and bradykinin (9.6 +/- 2.0 vs. 1.0 +/- 0.2 microA/cm2), while retaining high transepithelial resistance (227 +/- 5 omega.cm2). VIT/USG/AIR led to the appearance of cilia, an increase in the depth of the cell sheets (50 vs. 10 microns), longer and more frequent apical microvilli, and increased interdigitations of the basolateral membrane. Protein and DNA content were also significantly increased. Secretory granules were present which stained with antibody to goblet cells, but not to serous or mucous gland cells. CF cells grown in VIT/USG/AIR showed high baseline Isc (69 +/- 18 microA/cm2) and a proportionately larger inhibition of Isc by amiloride (70 +/- 10 vs. 34 +/- 3%). Isc did not respond to isoproterenol, and the response to bradykinin was 22% normal.

Bovine tracheal serous cell secretion: role of cAMP and cAMP-dependent protein kinase

The role of adenosine 3',5'-cyclic monophosphate (cAMP) and protein phosphorylation during beta-adrenergic receptor stimulation of bovine tracheal gland serous cells was investigated in vitro. Isoproterenol, a beta-adrenergic agonist, increased the secretion of 35S-labeled molecules. Intracellular cAMP levels were increased within 1 min after stimulation of bovine tracheal gland serous cells with isoproterenol. The dose-response relationship for isoproterenol-stimulated generation of cAMP correlated with the dose-response relationship for isoproterenol-stimulated secretion of 35S-labeled molecules. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine potentiated both isoproterenol-evoked secretion of 35S-labeled molecules and the production of intracellular cAMP, and the beta-adrenergic receptor antagonist propranolol completely blocked both effects. The secretory response of the cells to isoproterenol could be mimicked by the cAMP analogues 8-bromoadenosine 3',5'-cyclic monophosphate and dibutyryl adenosine 3',5'-cyclic monophosphate. Activity of cAMP-dependent kinase was measured in soluble and particulate cell extracts. cAMP effected the state of phosphorylation of proteins associated with the soluble but not the particulate fraction. These studies are consistent with the hypothesis that beta-adrenergic stimulation of secretion from bovine tracheal gland serous cells occurs via a cAMP-mediated pathway and that one of the molecular events in this pathway is cAMP-dependent protein phosphorylation.

Cloning of human airway 15-lipoxygenase: identity to the reticulocyte enzyme and expression in epithelium

Lipoxygenases constitute a family of enzymes which are implicated in a variety of inflammatory disorders including asthma. Although the 15-lipoxygenase has been identified as the major route of arachidonic acid metabolism in human lung, airway epithelial cells, eosinophils, and developing red cells, the localization of the enzyme within lung has not been clearly defined. Furthermore, the existence of isoforms of 15-lipoxygenase in different tissues has recently been proposed. To address these issues, we isolated a 2.6-kb cDNA encoding human airway 15-lipoxygenase from a human bronchus cDNA library using a previously characterized reticulocyte 15-lipoxygenase cDNA as a probe. The airway 15-lipoxygenase sequence was found to be identical to that of the reticulocyte-derived clone. Immunocytochemical studies using an antibody to human recombinant 15-lipoxygenase specifically localizes the enzyme to the basal and ciliated cells of the trachea, bronchi, and bronchioles. Staining for 15-lipoxygenase is not present in the airway secretory epithelial cells, epithelial cells located in the gas-exchanging regions of lung, vascular structures, or inflammatory cells. Taken together these results suggest that the 15-lipoxygenase of human lung is identical to that of the reticulocyte enzyme and is preferentially expressed in airway epithelium.

Changes in permeability of dog tracheal epithelium in response to hydrostatic pressure

We tested the hypothesis that, in asthma, the airway epithelial damage and leakage of blood proteins into the lumen are the result of edema and raised submucosal hydrostatic pressure. Sheets of dog tracheal epithelium were mounted in Ussing chambers, and the effects of transepithelial hydrostatic pressure differences (delta P) on conductance (G), [3H]mannitol flux (Jman), and fluorescein isothiocyanate-albumin flux (Jalb) were determined. delta P values of 20 cmH2O directed from the mucosal to submucosal side of the tissue (m----s) had no significant effects on G, Jman, Jalb, or tissue ultrastructure. delta Ps----m caused increases in conductance (G) with a maximal effect at approximately 20 cmH2O. delta Ps----m of 20 cmH2O significantly (P less than 0.05) increased G (4.3 +/- 0.6 to 10.6 +/- 1.6 mS/cm2), Jman s----m (18 +/- 5 to 411 +/- 54 nmol.cm-2.h-1), J(alb)s----m (0.3 +/- 0.1 to 6.0 +/- 2.0 micrograms.cm-2.h-1), and J(alb)m----s (0.7 +/- 0.3 to 1.8 +/- 0.4 micrograms.cm-2.h-1). Jman m----s was not affected. On removal of delta P, G and Jman s----m returned to preexposure values, though J(alb)s----m remained slightly elevated at 1.1 +/- 0.3 micrograms.cm-2.h-1. Morphologically, delta Ps----m caused dilation of lateral intercellular spaces, disruption of tight junctions, and submucosal edema. The large increases in s----m fluxes of albumin and mannitol are consistent with bulk flow of fluid toward the lumen via the areas of epithelial damage.

Ion transport by cultures of human tracheobronchial submucosal glands

Acini of human tracheobronchial submucosal glands were isolated by enzymatic disaggregation, and, when plated on flasks coated with human placental collagen (HPC) in media containing Ultroser G serum substitute (USG) and a variety of growth factors (GF), they became confluent after 14-20 days. The cells were then isolated by trypsinization and replated in media containing USG and GF at 10(6) cells/cm2 on porous-bottomed inserts coated with HPC. Confluent monolayers formed on day 1 after replating and were studied on day 10. Transepithelial resistance and short-circuit current (Isc) were 578 +/- 89 omega.cm2 and 12.9 +/- 1.9 microA/cm2 (means +/- SE, n = 23 cell sheets). The potency sequence for stimulation of Isc by mediators was methacholine greater than bradykinin greater than isoproterenol approximately or equal to phenylephrine. Amiloride decreased baseline Isc by 42 +/- 9% (n = 6 cell sheets) but had little effect on the Isc response to mediators. Diphenylamine-2-carboxylic acid, however, had no effect on baseline Isc but markedly inhibited the Isc response to all mediators. These results show that submucosal gland cells from human trachea can be grown in culture to produce epithelial sheets of high resistance, which secrete Cl in response to bradykinin and alpha- and beta-adrenergic and cholinergic agents.

Altered ion transport by tracheal glands in cystic fibrosis

Acini of tracheal glands from 12 humans without cystic fibrosis (CF) and from two CF patients were isolated by enzymatic digestion. They were plated on flasks coated with human placental collagen (HPC) in media containing Ultroser G serum substitute and a variety of growth factors. Confluent cell sheets formed after 20 days. Cells were then isolated by trypsinization and replated at 10(6) cells/cm2 onto porous-bottomed inserts coated with HPC. Confluent sheets formed on day 1 after replating and were studied on day 10 in Ussing chambers. Transepithelial resistance (Rte) and baseline short-circuit current (Isc) of CF cultures (171 +/- 67 omega.cm2, 3.8 +/- 0.8 microA/cm2; n = 5) were significantly less than non-CF (541 +/- 116 omega.cm2, 9.9 +/- 2.3 microA/cm2; n = 14). Responses in Isc to mediators were also significantly reduced in CF: isoproterenol (10(-5)M) = 0.04 +/- 0.04 vs. 1.9 +/- 0.6; methacholine (10(-5)M) = 0.2 +/- 0.1 vs. 7.1 +/- 1.7; bradykinin (10(-6)M) = 0.4 +/- 0.1 vs. 5.0 +/- 1.0 microA/cm2; n = 5 for CF, n = 14 for non-CF. When CF and non-CF cells were matched for baseline Isc and Rte, the responses of CF cells to mediators still remained statistically lower than normal. The reduced responses of CF cells to bradykinin and methacholine, in addition to isoproterenol, suggest that both Ca-dependent and adenosine 3',5'-cyclic monophosphate-dependent regulation of Cl secretion are defective in CF tracheobronchial glands. The resulting reduction in fluid secretion by glands may contribute to the accumulation of airway mucus in CF.

Hyaluronic acid in a cardiac myxoma: a biochemical and histological analysis

Cardiac myxoma is the most common primary tumor of the heart. This tumor has a gelatinous stroma that is thought to be composed of glycosaminoglycans, the classical acid mucopolysaccharide ground substance. We examined both biochemically and histologically the hyaluronic acid in a case of cardiac myxoma using a newly developed hyaluronic acid-binding protein probe. We observed that hyaluronic acid was localized in the amorphous stroma and occurred at levels 30 times that found in normal atrial septum.

Simple technique for culture of highly differentiated cells from dog tracheal epithelium

Cultures of dog tracheal epithelium have proved very useful in studies of ion transport. Their short-circuit current (Isc), however, is usually much less than the original tissue. We have tested a variety of conditions in an attempt to produce large numbers of cells with electrical properties comparable with the original tissue. Of several growth supports, human placental collagen (HPC) gave the best results. When plated at 2.5 x 10(5) cells/cm2 onto HPC, cells grown in serum-free, growth factor-supplemented medium (GF medium) showed increases in cells per unit area, thickness of cell sheet, numbers of domes, numbers of apical microvilli, and degree of basolateral membrane interdigitation compared with cells grown in medium containing 5% fetal calf serum (FCS medium). Transepithelial resistance (Rte) and the increases in Isc and intracellular Ca in response to isoproterenol were also increased. However, baseline Isc and adenosine 3',5'-cyclic monophosphate levels were not changed. The improved electrical properties were maintained for up to 4 mo. GF medium combined with an air interface produced further increases in Rte, Isc, and changes in Isc in response to amiloride and isoproterenol. Ultrastructural features such as the presence of cilia, greater thickness of the cell sheet, and increased amplification of apical and basolateral membranes also indicated improved differentiation. Our results show that GF medium and an air interface can be combined with a simple growth support and a relatively low-plating density to allow the easy production of greater than 500 cm2 of cultured cells from a single trachea, with a level of differentiation similar to that of the original tissue.

Etiology of intestinal damage in gastroschisis, II. Timing and reversibility of histological changes, mucosal function, and contractility

Previous work in the fetal lamb examined the relative effects of amniotic fluid and bowel constriction in the etiology of bowel damage in gastroschisis. The present study used the same model to assess the timing and reversibility of these changes during gestation. Gastroschisis was created at 80 days' gestation, and a tape was placed around the bowel to cause gradual constriction with growth. Lambs were killed at 100 days, 120 days, and term. Bowel damage was assessed using histology, mucosal enzyme activity, and in vitro motility. In an additional "repaired" group, the constrictor was removed at 120 days, a silastic pouch placed over the bowel, and bowel damage assessed at term. Normal fetuses at each gestational age were used as controls. A fibrous peel was observed at all gestational ages. Mucosal villous atrophy and mesenteric venous and lymphatic dilation were mild at 100 and 120 days, but severe at term. These changes were present but mild in repaired animals at term. Mucosal enzyme activity decreased gradually with gestational age; inhibition of maltase activity was maximal at term, and was significantly reversed by repair, whereas inhibition of aminooligopeptidase activity was maximal at 120 days, and was not affected by repair. Protein/DNA, DNA/weight, and protein/weight ratios showed that repaired mucosal cells were significantly more proliferative, smaller, and less mature than control or gastroschisis cells. In vitro motility studies demonstrated a mild decrease in contractility at 100 and 120 days, and a large decrease at term. This deleterious effect at the end of gestation was only partially reversed by repair in utero.(ABSTRACT TRUNCATED AT 250 WORDS)

Denervation-induced inflammation in the rat

We report that section of the sciatic and saphenous nerves, in the hindlimb of the rat, evokes an inflammatory response in the denervated tissue that can be distinguished from the previously described peptide-mediated neurogenic inflammation. This novel form of neurogenic inflammation has a very delayed onset (9.75 +/- 2.1 h, mean +/- S.E.M., n = 8), persists for more than 30 h, and is characterized by a marked neutrophilic cellular infiltrate. These features cannot be mimicked by electrical stimulation of the peripheral nerve and are not prevented by either prior application of local anesthetics to the nerve lesion site or by neonatal treatment with capsaicin.

Effect of repetitive brief episodes of cardiac ischemia on 31P magnetic resonance spectroscopy in the cat

Angina is characterized by brief periods of ischemia followed by reperfusion; the cumulative effect of these episodes on energetics of the myocardium has not been fully elucidated. This study used an in vivo feline model for the assessment of high-energy phosphate compounds during brief sequential periods of ischemia and reperfusion. Nine adult, open-chest, anesthetized cats were prepared with a reversible occluder around the proximal left anterior descending artery and a 1.2-cm-inside diameter coil sutured on the myocardial surface in the distribution of the left anterior descending coronary artery. Levels of PCr, Pi, and ATP (beta-phosphate signal) were measured by 31P MRS in a GE CSI 2-T NMR spectrometer/imager. Measurements were obtained during a control period and during three successive occlusion-deocclusion periods of roughly 12 and 20 min' duration, respectively. The last deocclusion period was observed for 60 min. Electron microscopy was performed in two animals. PCr declined (P less than 0.01) rapidly following each occlusion to 51 +/- 5.2% (occlusion 1), 53 +/- 5.8% (occlusion 2), and 48 +/- 5.7% (occlusion 3) of the control value by 6 min. Pi rose (P less than 0.01) with the three sequential occlusions to 253 +/- 46, 288 +/- 57, and 277 +/- 46%, respectively. PCr and Pi returned to baseline promptly with reperfusion, while ATP showed a gradual decline throughout the experiment, decreasing to 77 +/- 7.2% of control at the end of the last reperfusion (P less than 0.05). Although PCr returned to baseline during reperfusion, ATP did not, suggesting a reduction in the nucleotide pool. These findings indicate that the repeated episodes of ischemia, which are insufficient to produce necrosis, can have an effect on myocardial high-energy phosphate metabolism as evidenced by mild depletion of ATP.