Glucocorticoids can affect Pseudomonas aeruginosa (ATCC 27853) internalization and intracellular calcium concentration in cystic fibrosis bronchial epithelial cells.

BACKGROUND AND OBJECTIVE: Glucocorticoids (GCs) are anti-inflammatory agents, but their use in cystic fibrosis (CF) is controversial. In CF, the early colonization with Pseudomonas aeruginosa is mainly due to nonmucoid strains that can internalize, and induce apoptosis in the epithelial cells. Uptake of P. aeruginosa by the epithelial cells and subsequent apoptosis may prevent colonization of P. aeruginosa in CF airways. In the airway epithelia, several other biological effects, including an anti-secretory role by decreasing intracellular Ca(2+) concentration have been described for this anti-inflammatory drug. However, the effects of GCs on the nonmucoid P. aeruginosa internalization and intracellular Ca(2+) in CF bronchial epithelial cells have not been evaluated. METHODS: We used cultured human CF bronchial airway epithelial cell (CFBE) monolayers to determine P. aeruginosa internalization, apoptosis, and intracellular Ca(2+)concentration in CF bronchial epithelial cells. Cells were treated with IL-6, IL-8, dexamethasone, betamethasone, or budesonide. RESULTS: GCs in co-treatments with IL-6 reversed the effect of IL-6 by decreasing the internalization of P. aeruginosa in the CFBE cells. GCs decreased the extent of apoptosis in CFBE cells infected with internalized P. aeruginosa, and increased the intracellular Ca(2+) concentration. CONCLUSION: These findings suggest that if internalization of P. aeruginosa reduces infection, GC therapy would increase the risk of pulmonary infection by decreasing the internalization of P. aeruginosa in CF cells, but GCs may improve airway hydration by increasing the intracellular Ca(2+) concentration. Whether the benefits of GC treatment outweigh the negative effects is questionable, and further clinical studies need to be carried out.

N-acetylcysteine and azithromycin affect the innate immune response in cystic fibrosis bronchial epithelial cells in vitro.

BACKGROUND AND OBJECTIVE: We have previously reported that N-acetylcysteine (NAC), ambroxol and azithromycin (AZM) (partially) correct the chloride efflux dysfunction in cystic fibrosis bronchial epithelial (CFBE) cells with the ΔF508 homozygous mutation in vitro. METHODS: In the present paper, we further investigated possible immunomodulatory effects of these drugs on the regulation of the innate immune system by studying the expression of the cytosolic NOD-like receptors NLRC1 and NLRC2, and interleukin (IL)-6 production in CFBE cells. RESULTS: Under basal conditions, PCR and Western Blot data indicate that the NLRC2 receptor has a reduced expression in CF cells as compared to non-CF (16HBE) cells, but that the NLRC1 expression is the same in both cell lines. AZM significantly upregulated NLRC1 and NLRC2 while NAC upregulated only NLRC2 receptor expression in CF cells. Reduced basal IL-6 production was found in CF cells as compared to non-CF cells. MDP (an NLRC2 agonist), NAC and AZM, but not Tri-DAP (an NLRC1 agonist), increased IL-6 production in CF cells, indicating that in CF cells IL-6 upregulation is independent of NLRC1, but involves the activation of NLRC2. CONCLUSION: Overall, the results indicate that NAC and AZM not only can correct the chloride efflux dysfunction but also have a weakly strengthening effect on the innate immune system.

Pharmacological treatment of the basic defect in cystic fibrosis.

Cystic fibrosis (CF) is a genetic disease due to a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel in epithelial cells. There are about 1900 mutations, divided in several groups, for example, stop mutations, mutations affecting the permeability of the channel, and mutations in which the mutated CFTR is recognized as abnormal and destroyed. Pharmacological treatment has become possible for stop mutations (about 10% of the patients), and for a rare mutation affecting channel permeability. For the majority of patients, however, that have a mutation in which the mutated CFTR is destroyed on its way to the cell membrane, research is still in progress, although a number of compounds have been identified that (at least partly) corrects the error in chloride transport.

X-ray microanalysis in the scanning electron microscope.

X-ray microanalysis conducted using the scanning electron microscope is a technique that allows the determination of chemical elements in bulk or semi-thick specimens. The lowest concentration of an element that can be detected is in the order of a few mmol/kg or a few hundred parts per million, and the smallest amount is in the order of 10(-18) g. The spatial resolution of the analysis depends on the thickness of the specimen. For biological specimen analysis, care must be taken to prevent displacement/loss of the element of interest (usually ions). Protocols are presented for the processing of frozen-hydrated and freeze-dried specimens, as well as for the analysis of small volumes of fluid, cell cultures, and other specimens. Aspects of qualitative and quantitative analysis are covered, including limitations of the technique.

Isolation and culture of primary human nasal epithelial cells from anesthetized nasal epithelia.

CONCLUSION: Using a local anesthetic agent before obtaining nasal biopsies by nasal brushing makes the sampling procedure smooth, avoids lacrimation, nasal itching/irritation, and/or sneezing and provides enough viable cells to establish primary cultures. OBJECTIVES: To examine the use of local anesthesia to avoid the irritation experienced by the subject when nasal biopsies are obtained by nasal brushing in order to culture viable nasal epithelial cells. METHODS: Nasal epithelial cells were collected from the mid-part of the inferior turbinate of healthy volunteers by brushing with interdental brushes, after spraying a topical anesthetic on the nasal mucosa. Immunocytochemistry was performed to assess the purity of epithelial cells. RESULTS: Cell samples ranging from 1.16 × 10(5) to 3.06 × 10(5) cells/per sample were obtained. Of 11 samples, 7 formed confluent cultures, while the remaining 4 samples showed only patches of epithelial cells. Neither fungal nor bacterial contamination posed a problem. Immunocytochemistry of the cytospin slides confirmed the presence of epithelial cells in the cultures. No adverse effects were experienced by the volunteers.

Modulation of ENaC, CFTR, and iNOS expression in bronchial epithelial cells after stimulation with Staphylococcus epidermidis (94B080) and Staphylococcus aureus (90B083).

Bacteria affect the respiratory epithelium, which is covered by airway surface liquid (ASL) and mucus. Ion concentrations in the ASL are determined by the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na(+) channel (ENaC). Neonatal sepsis is a major risk factor for subsequent pulmonary disease in preterm newborns. Predominating are coagulase-negative staphylococci (e.g., Staphylococccus epidermidis and Staphylococccus aureus). The aim of this study was to investigate modulation of CFTR, ENaC, mucins, proinflammatory cytokines, and inducible nitric oxide synthase (iNOS) in respiratory epithelial cells after S. epidermidis 94B080 and S. aureus 90B083 exposure. Bronchial epithelial cells were incubated with S. epidermidis 94B080 and S. aureus 90B083 (neonatal blood isolates) for 1-36 h. Expression of CFTR, ENaC, iNOS, and mucins was analyzed by real-time PCR and Western blotting. Release of cytokines was analyzed by ELISA, and production of NO by the Griess assay. Expression of CFTR significantly decreased after 36 h incubation with S. epidermidis and more prominently with S. aureus, whereas S. epidermidis caused a significant increase in the expression of ß- and γ-ENaC. Expression of iNOS increased, but NO was not detected. Both staphylococci caused a decrease in the intracellular Ca(2+) concentration. S. aureus induced increased secretion of IL-6, IL-8, and transforming nuclear factor (TNF)-α in a time-dependent manner as compared with S. epidermidis. In conclusion, expression of ENaC, CFTR, and iNOS is modulated by exposure to S. aureus 90B083 and S. epidermidis 94B080. S. aureus is more potent in causing release of IL-6, IL-8, and TNF-α by bronchial epithelial cells as compared with S. epidermidis. The mRNA expression for the mucus proteins MUC2, MUC5AC, and MUC5B could not be measured, neither in the presence nor in the absence of bacteria.

The effect of ambroxol on chloride transport, CFTR and ENaC in cystic fibrosis airway epithelial cells.

Ambroxol, a mucokinetic anti-inflammatory drug, has been used for treatment of cystic fibrosis (CF). The respiratory epithelium is covered by the airway surface liquid (ASL), the thickness and composition of which is determined by Cl(-) efflux via the cystic fibrosis transmembrane conductance regulator (CFTR) and Na(+) influx via the epithelial Na(+) channel (ENaC). In cells expressing wt-CFTR, ambroxol increased the Cl(-) conductance, but not the bicarbonate conductance of the CFTR channels. We investigated whether treatment with ambroxol enhances chloride transport and/or CFTR and ENaC expression in CF airway epithelial cells (CFBE) cells. CFBE cells were treated with 100 µM ambroxol for 2, 4 or 8 h. mRNA expression for CFTR and ENaC subunits was analysed by real-time polymerase chain reaction (RT-PCR); protein expression was measured by Western blot. The effect of ambroxol on Cl(-) transport was measured by Cl(-) efflux measurements with a fluorescent chloride probe. Ambroxol significantly stimulated Cl(-) efflux from CFBE cells (a sixfold increase after 8 h treatment), and enhanced the expression of the mRNA of CFTR and α-ENaC, and of the CFTR protein. No significant difference was observed in ß-ENaC after exposure to ambroxol, whereas mRNA expression of γ-ENaC was reduced. No significant effects of ambroxol on the ENaC subunits were observed by Western blot. Ambroxol did not significantly affect the intracellular Ca(2+) concentration. Upregulation of CFTR and enhanced Cl(-) efflux after ambroxol treatment should promote transepithelial ion and water transport, which may improve hydration of the mucus, and therefore be beneficial to CF-patients.

The effect of NO-donors on chloride efflux, intracellular Ca(2+) concentration and mRNA expression of CFTR and ENaC in cystic fibrosis airway epithelial cells.

Since previous studies showed that the endogenous bronchodilator, S-nitrosglutathione (GSNO), caused a marked increase in CFTR-mediated chloride (Cl(-)) efflux and improved the trafficking of CFTR to the plasma membrane, and that also the nitric oxide (NO)-donor GEA3162 had a similar, but smaller, effect on Cl(-) efflux, it was investigated whether the NO-donor properties of GSNO were relevant for its effect on Cl(-) efflux from airway epithelial cells. Hence, the effect of a number of other NO-donors, sodium nitroprusside (SNP), S-nitroso-N-acetyl-DL-penicillamine (SNAP), diethylenetriamine/nitric oxide adduct (DETA-NO), and diethylenetriamine/nitric oxide adduct (DEA-NONOate) on Cl(-) efflux from CFBE (∆F508/∆F508-CFTR) airway epithelial cells was tested. Cl(-) efflux was determined using the fluorescent N-(ethoxycarbonylmethyl)-6-methoxyquinoliniu bromide (MQAE)-technique. Possible changes in the intracellular Ca(2+) concentration were tested by the fluorescent fluo-4 method in a confocal microscope system. Like previously with GSNO, after 4 h incubation with the NO-donor, an increased Cl(-) efflux was found (in the order SNAP>DETA-NO>SNP). The effect of DEA-NONOate on Cl(-) efflux was not significant, and the compound may have (unspecific) deleterious effects on the cells. Again, as with GSNO, after a short (5 min) incubation, SNP had no significant effect on Cl(-) efflux. None of the NO-donors that had a significant effect on Cl(-) efflux caused significant changes in the intracellular Ca(2+) concentration. After 4 h preincubation, SNP caused a significant increase in the mRNA expression of CFTR. SNAP and DEA-NONOate decreased the mRNA expression of all ENaC subunits significantly. DETA-NO caused a significant decrease only in α-ENaC expression. After a short preincubation, none of the NO-donors had a significant effect, neither on the expression of CFTR, nor on that of the ENaC subunits in the presence and absence of L-cysteine. It can be concluded that the effect of GSNO on Cl(-) efflux is, at least in part, due to its properties as an NO-donor, and the effect is likely to be mediated by CFTR, not by Ca(2+)-activated Cl(-) channels.

The effect of S-nitrosoglutathione and L-cysteine on chloride efflux from cystic fibrosis airway epithelial cells.

The endogenous bronchodilator, S-nitrosoglutathione (GSNO), has been proposed as a possible pharmacological remedy that reverses the ΔF508-CFTR (cystic fibrosis transmembrane conductance regulator) maturation defect and increases CFTR-mediated chloride efflux in cultured cystic fibrosis airway epithelial cells (CFBE41o(-)). It has also been reported that L-cysteine enhanced S-nitrosothiol uptake and increased the intracellular S-nitrosothiol levels, likely through transnitrosation chemistry. The present study investigated whether L-cysteine augmented the effect of GSNO on chloride efflux from CF airway epithelial cells. Treatment with 10 µM GSNO combined with 20 µM L-cysteine resulted in increased chloride efflux from CFBE41o(-) cells after 5 minutes exposure compared to the control efflux rate and to the efflux rate in the presence of L-cysteine alone as measured using the fluorescent dye N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE). Chloride efflux rates from these cells after 4h exposure to GSNO and L-cysteine were not different from control. Treatment with 10 µM GSNO alone increased chloride efflux from CFBE41o(-) cells after 4h but not at shorter incubation times. GSNO with or without L-cysteine did not alter epithelial tight junction integrity. In conclusion, a combination of GSNO with L-cysteine led to significant increase in chloride efflux in CFBE41o(-) cells but the effect was transient and not sustained beyond minutes.

Effect of duramycin on chloride transport and intracellular calcium concentration in cystic fibrosis and non-cystic fibrosis epithelia.

The lantibiotic duramycin (Moli1901, Lancovutide) has been suggested as a drug of choice in the treatment for cystic fibrosis (CF). It has been proposed that duramycin may stimulate chloride secretion through Ca²(+) -activated Cl⁻ channels (CaCC). We investigated whether duramycin exhibited any effect on Cl⁻ efflux and intracellular Ca²(+) concentration ([Ca²(+)](i)) in CF and non-CF epithelial cells. Duramycin did stimulate Cl⁻ efflux from CF bronchial epithelial cells (CFBE) in a narrow concentration range (around 1 µM). However, 100 and 250 µM of duramycin inhibited Cl⁻ efflux from CFBE cells. An inhibitor of the CF transmembrane conductance regulator (CFTR(inh)₋172) and a blocker of the capacitative Ca²(+) entry, gadolinium chloride, inhibited the duramycin-induced Cl⁻ efflux. No effect on Cl⁻ efflux was observed in non-CF human bronchial epithelial cells (16HBE), human airway submucosal gland cell line, human pancreatic epithelial cells, CF airway submucosal gland epithelial cells, and CF pancreatic cells. The [Ca²(+)](i) was increased by 3 µM duramycin in 16HBE cells, but decreased after 1, and 3 µM of duramycin in CFBE cells. The results suggest that the mechanism responsible for the stimulation of Cl⁻ efflux by duramycin is mainly related to unspecific changes of the cell membrane or its components rather than to effects on CaCC.

Tissue engineering and the use of stem/progenitor cells for airway epithelium repair.

Stem/progenitor cells can be used to repair defects in the airway wall, resulting from e.g., tumors, trauma, tissue reactions following long-time intubations, or diseases that are associated with epithelial damage. Several potential sources of cells for airway epithelium have been identified. These can be divided into two groups. The first group consists of endogenous progenitor cells present in the respiratory tract. This group can be subdivided according to location into (a) a ductal cell type in the submucosal glands of the proximal trachea, (b) basal cells in the intercartilaginous zones of the lower trachea and bronchi, (c) variant Clara cells (Clara v-cells) in the bronchioles and (d) at the junctions between the bronchioles and the alveolar ducts, and (e) alveolar type II cells. This classification of progenitor cell niches is, however, controversial. The second group consists of exogenous stem cells derived from other tissues in the body. This second group can be subdivided into: (a) embryonic stem (ES) cells, induced pluripotent stem (iPS) cells, or amniotic fluid stem cells, (b) side-population cells from bone marrow or epithelial stem cells present in bone marrow or circulation and (c) fat-derived mesenchymal cells. Airway epithelial cells can be co-cultured in a system that includes a basal lamina equivalent, extracellular factors from mesenchymal fibroblasts, and in an air-liquid interface system. Recently, spheroid-based culture systems have been developed. Several clinical applications have been suggested: cystic fibrosis, acute respiratory distress syndrome, chronic obstructive lung disease, pulmonary fibrosis, pulmonary edema, and pulmonary hypertension. Clinical applications so far are few, but include subglottic stenosis, tracheomalacia, bronchiomalacia, and emphysema.

The effect of N-acetylcysteine on chloride efflux from airway epithelial cells.

Defective chloride transport in epithelial cells increases mucus viscosity and leads to recurrent infections with high oxidative stress in patients with CF (cystic fibrosis). NAC (N-acetylcysteine) is a well known mucolytic and antioxidant drug, and an indirect precursor of glutathione. Since GSNO (S-nitrosoglutathione) previously has been shown to be able to promote Cl- efflux from CF airway epithelial cells, it was investigated whether NAC also could stimulate Cl- efflux from CF and non-CF epithelial cells and through which mechanisms. CFBE (CF bronchial epithelial cells) and normal bronchial epithelial cells (16HBE) were treated with 1 mM, 5 mM, 10 mM or 15 mM NAC for 4 h at 37 degrees C. The effect of NAC on Cl- transport was measured by Cl- efflux measurements and by X-ray microanalysis. Cl- efflux from CFBE cells was stimulated by NAC in a dose-dependent manner, with 10 mM NAC causing a significant increase in Cl- efflux with nearly 80% in CFBE cells. The intracellular Cl- concentration in CFBE cells was significantly decreased up to 60% after 4 h treatment with 10 mM NAC. Moreover immunocytochemistry and Western blot experiments revealed expression of CFTR channel on CFBE cells after treatment with 10 mM NAC. The stimulation of Cl- efflux by NAC in CF airway epithelial cells may improve hydration of the mucus and thereby be beneficial for CF patients.

CFTR and tight junctions in cultured bronchial epithelial cells.

Airway epithelial salt and water transport takes place through paracellular and transcellular pathways. This transport depends critically on the epithelial sodium channel (ENaC) and the cystic fibrosis transmembrane conductance regulator (CFTR), operating in concert with the paracellular pathway through the tight junctions (TJ). Normal (16HBE14o-), cystic fibrosis (CFBE41o-), and corrected CFBE41o- (CFBE41o-pCep4 overexpressing wtCFTR) airway epithelial cell lines were cultured under isotonic conditions. Transepithelial electrical resistance (TEER) was measured as indicator of the tightness of the cultures. Morphology was investigated by immunofluorescence and paracellular permeability by lanthanum nitrate or [14C] mannitol as permeability markers. The CFTR-defective cell line CFBE41o- developed higher TEER than its corrected counterpart CFBE41o-pCep4. Addition of a specific inhibitor of CFTR (CFTR(inh)-172) to 16HBE14o- and CFBE41o-pCep4 cells resulted in a time-dependent increase in TEER, whereas stimulation of CFTR by IBMX and forskolin caused a decrease. Permeability to lanthanum and [14C] mannitol was lower in CFBE41o- and in 16HBE14o- cells exposed to CFTR(inh)-172, compared to untreated 16HBE14o- and CFBE41o-pCep4 cells, respectively. 16HBE14o- cells exposed to IBMX and forskolin showed higher permeability to lanthanum but lower permeability to [14C] mannitol compared to control. Immunofluorescence revealed a disorganization of F-actin and alpha-tubulin in 16HBE14o- cells and CFBE41o- pCep4 exposed to CFTR(inh)-172 and in CFBE41o- cells. Changes in F-actin and alpha-tubulin in 16HBE14o- cells exposed to IBMX and forskolin were also seen. These results suggest the possibility of an interaction between CFTR and the TJ protein complex, probably via the cytoskeleton.

Azithromycin increases chloride efflux from cystic fibrosis airway epithelial cells.

It was investigated whether azithromycin (AZM) stimulates chloride (Cl-) efflux from cystic fibrosis (CF) and non-CF airway epithelial cells, possibly secondary to up-regulation of the multidrug resistance protein (MDR). CF and non-CF human airway epithelial cell lines (CFBE and 16HBE) were treated with 0.4, 4, and 40 microg/mL AZM for 4 days. Cl- efflux was explored in the presence or absence of specific inhibitors of CFTR and alternative Cl- channels. Six CF patients received AZM (500 mg daily) for 6 months. The percentage of predicted forced vital capacity (FVC%), forced expiratory volume (FEV1%), and the number of acute exacerbations were compared before and after treatment. Nasal biopsies were taken before and after treatment, and mRNA expression of MDR and CFTR was determined by in situ hybridization. A significant dose-dependent increase of Cl- efflux from CFBE cells (but not from 16HBE cells) was observed after AZM treatment. A CFTR inhibitor significantly reduced AZM-stimulated Cl- efflux from CFBE cells. A significant improvement in FEV1%, and fewer exacerbations were observed. AZM treatment did not affect mRNA expression of MDR and CFTR. The stimulation of Cl- efflux could be part of the explanation for the clinical improvement seen among the patients.

Transforming growth factor-beta-activated protein kinase 1-binding protein (TAB)-1alpha, but not TAB1beta, mediates cytokine-induced p38 mitogen-activated protein kinase phosphorylation and cell death in insulin-producing cells.

Previous studies have indicated that the p38 MAPK participates in signaling events that lead to the death of the insulin-producing beta-cell. The aim of the present study was to elucidate the role of the TGF-beta-activated protein kinase 1-binding protein 1 (TAB1) in the cytokine-induced activation of p38. Levels of TAB1 mRNA and protein were analyzed by real-time PCR and immunoblotting, and TAB1 expression in mouse and human islet cells was down-regulated using lipofection of diced-small interfering RNA. TAB1 overexpression in beta-TC6 cells was achieved by transient transfections followed by fluorescence activated cell sorting. Phosphorylation of p38, c-Jun N-terminal kinase, and ERK was assessed by immunoblotting, and viability was determined using vital staining with bisbenzimide and propidium iodide. We observed that TAB1 is expressed in insulin-producing cells. Cytokine (IL-1beta + interferon-gamma)-stimulated p38 phosphorylation was significantly increased by TAB1alpha overexpression, but not TAB1beta overexpression, in beta-TC6 cells. The TAB1alpha-augmented p38 phosphorylation was paralleled by an increased cell death rate. Treatment of islet cells with diced-small interfering RNA specific for TAB1, but not for TGF-beta-activated kinase 1, resulted in lowered cytokine-induced p38 phosphorylation and protection against cell death. The cytokine-induced phosphorylation of c-Jun N-terminal kinase and ERK was not affected by changes in TAB1 levels. Finally, TAB1 phosphorylation was decreased by the p38 inhibitor SB203580. We conclude that TAB1alpha, but not TAB1beta, plays an important role in the activation of p38 in insulin-producing cells and therefore also in cytokine-induced beta-cell death.

Effects of hyperosmotic stress on cultured airway epithelial cells.

Inhalation of hyperosmotic solutions (salt, mannitol) has been used in the treatment of patients with cystic fibrosis or asthma, but the mechanism behind the effect of hyperosmotic solutions is unclear. The relation between osmolarity and permeability changes was examined in an airway cell line by the addition of NaCl, NaBr, LiCl, mannitol, or xylitol (295-700 mOsm). Transepithelial resistance was measured as an indicator of the tightness of the cultures. Cell-cell contacts and morphology were investigated by immunofluorescence and by transmission electron microscopy, with lanthanum nitrate added to the luminal side of the epithelium to investigate tight junction permeability. The electrolyte solutions caused a significant decrease in transepithelial resistance from 450 mOsm upwards, when the hyperosmolar exposure was gradually increased from 295 to 700 mOsm; whereas the nonelectrolyte solutions caused a decrease in transepithelial resistance from 700 mOsm upwards. Old cultures reacted in a more rigid way compared to young cultures. Immuno-fluorescence pictures showed weaker staining for the proteins ZO-1, claudin-4, and plakoglobin in treated samples compared to the control. The ultrastructure revealed an increased number of open tight junctions as well as a disturbed morphology with increasing osmolarity, and electrolyte solutions opened a larger proportion of tight junctions than nonelectrolyte solutions. This study shows that hyperosmotic solutions cause the opening of tight junctions, which may increase the permeability of the paracellular pathway and result in increased transepithelial water transport.

X-ray microanalysis in the scanning electron microscope.

X-ray microanalysis conducted using the scanning electron microscope is a technique that allows the determination of chemical elements in bulk or semithick specimens. The lowest concentration of an element that can be detected is in the order of a few mmol/kg or a few hundred parts per million, and the smallest amount is in the order of 10(-18) g. The spatial resolution of the analysis depends on the thickness of the specimen. For biological specimen analysis, care must be taken to prevent displacement/loss of the element of interest (usually ions). Protocols are presented for the processing of frozen-hydrated and freeze-dried specimens, as well as for the analysis of small volumes of fluid, cell cultures and other specimens. Aspects of qualitative and quantitative analysis are covered, including limitations of the technique.

Macrovascular changes in mice overexpressing human semicarbazide-sensitive amine oxidase in smooth muscle cells.

BACKGROUND: The catalytic activity of semicarbazide-sensitive amine oxidase (SSAO) is increased in diabetes, as well as in other disorders of cardiovascular origin. Our hypothesis is that SSAO is involved in the synthesis or maturation of elastin in vascular tissue. An increased SSAO activity can thereby be involved in the development of vascular damage. METHODS: Elastin quantification was performed in aorta of transgenic mice overexpressing the human form of SSAO, using electron microscopy. Furthermore, lung capacity was measured using a spirometry-mimicking method, developed for mice. The effect of vasoactive substances was estimated by measuring mean arterial pressure and pulse pressure under anesthesia. RESULTS: No differences in elastin quantity or lung capacity could be observed between transgenic or nontransgenic littermates. Pulse pressure was higher in transgenic mice, and electron microscopy of aorta showed elastin fibers parallel with the aorta wall (ie, straight fibers instead of folded compared with control mice). No difference in the response to adrenaline or sodium chloride was observed between the transgenic and control mice. The control mice had a clear decrease in blood pressure (BP) with a longer duration as a response to injection of a nitric oxide (NO) donor, sodium nitroprusside, compared with transgenic mice where only a minor response was observed. The SSAO activity in serum of control mice was elevated in response to injection of the NO donor, but not in response to a ganglion blocker. CONCLUSIONS: An elevated pulse pressure, together with an abnormal elastin structure in the aorta, suggests a rigidity of large arteries as a result of an elevated SSAO activity as well as a physiologic role for SSAO in elastin maturation.

Activation of chloride transport in CF airway epithelial cell lines and primary CF nasal epithelial cells by S-nitrosoglutathione.

BACKGROUND: It has been suggested that low microM concentrations of S-nitrosoglutathione (GSNO), an endogenous bronchodilator, may promote maturation of the defective cystic fibrosis (CF) transmembrane conductance regulator (CFTR). Because nitric oxide (NO) and GSNO levels appear to be low in the CF airway, there is an interest in the possibility that GSNO replacement could be of therapeutic benefit in CF. METHODS: The effect of GSNO on chloride (Cl-) transport was investigated in primary nasal epithelial cells obtained from CF patients homozygous for the delF508 mutation, as well as in two CF cell lines (CFBE and CFSME), using both a fluorescent Cl- indicator and X-ray microanalysis. Maturation of delF508 CFTR was determined by immunoblotting. RESULTS: Treatment with 60 microM GSNO for 4 hours increased cAMP-induced chloride efflux in nasal epithelial cells from 18 out of 21 CF patients, but did not significantly affect Cl- efflux in cells from healthy controls. This Cl- efflux was confirmed by measurements with a fluorescent Cl- indicator in the CFBE and CFSME cell lines. The effect of GSNO on Cl- efflux in CFBE cells could be inhibited both by a specific thiazolidinone CFTR inhibitor (CFTRinh-172) and by 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonic acid (H2DIDS). X-ray microanalysis showed that, following 4 hours incubation with 60 microM GSNO, cAMP agonists caused a decrease in the cellular Cl- concentration in CFBE cells, corresponding to Cl- efflux. GSNO exposure resulted in an increase in the protein expression and maturation, as shown by immunoblot analysis. GSNO did not increase the cytosolic Ca2+ concentration in cultured airway epithelial cells. CONCLUSION: Previous studies have suggested that treatment with GSNO promotes maturation of delF508-CFTR, consistent with our results in this study. Here we show that GSNO increases chloride efflux, both in the two CF cell lines and in primary nasal epithelial cells from delF508-CF patients. This effect is at least in part mediated by CFTR. GSNO may be a candidate for pharmacological treatment of the defective chloride transport in CF epithelial cells.

A modified technique for the impregnation of lanthanum tracer to study the integrity of tight junctions on cells grown on a permeable substrate.

Ionic lanthanum is commonly used to trace permeability pathways across epithelia and endothelia in biological electron microscopy. A method for obtaining a uniformly dense precipitate of lanthanum is described. The method, which is a modification of the technique described by Shaklai and Tavassoli (1977) was suitable for fixation of cell cultures grown on permeable filter inserts and was successfully applied to study opening of tight junctions by hypertonic solutions in the airway epithelial cell line 16HBE14o(-). The preparation method formed the basis for a semiquantitative morphological determination in which the tight junctions were subdivided as "intact," "weakened," and "open." By using this modified technique, it could be demonstrated that opening of tight junctions in airway epithelial cells increased, with increasing osmolarity with electrolytes having a stronger effect than nonelectrolytes. A significant linear relationship was found between the osmolarity of the medium and the open state of the tight junctions (as determined by the semiquantitative morphological technique) or the transepithelial electrical resistance.