The elastase-induced expression of secretory leukocyte protease inhibitor is decreased in remodelled airway epithelium

During airway inflammation, proteinases such as human leukocyte elastase are actively secreted. Secretory leukocyte protease inhibitor is a major serine proteinase inhibitor, secreted by bronchial, bronchiolar and lung epithelial cells. We recently identified secretory leukocyte protease inhibitor in human nasal epithelium, exclusively in remodelled areas of the surface epithelium. We now investigated the influence of remodelling and inflammation of the nasal tissue on the in vitro capacity of these cells to respond to human leukocyte elastase. Primary cultures of surface epithelial cells were established from various nasal polyp samples. At confluency, cell cultures were exposed to different human leukocyte elastase concentrations. The secretory leukocyte protease inhibitor immunocytolocalisation, expression and secretion were then investigated. Immunocytochemistry, showed a human leukocyte elastase dose-dependent increase of secretory leukocyte protease inhibitor containing cells and a basal extracellular localization of secretory leukocyte protease inhibitor after incubation with 100 microg/ml human leukocyte elastase. The relative amount of secretory leukocyte protease inhibitor mRNA transcripts increased with respect to the human leukocyte elastase concentration. Nevertheless, the potential stimulation of secretory leukocyte protease inhibitor secretion by human leukocyte elastase was lower in the more remodelled and inflamed tissue. Our results suggest that the contribution of the surface epithelial cells of poorly remodelled tissues to the protection against the deleterious effect of neutrophil proteinases is severely decreased in highly remodelled and inflamed tissues.

Epithelial barrier integrity during in vitro wound repair of the airway epithelium

The surface epithelium of the airway mucosa forms a continuous barrier to a wide number of noxious substances present in the lumen. The restoration of the barrier integrity after injury represents a key issue in the defense capacity of the airway epithelium. Using an in vitro wound repair model of the airway epithelium, we investigated the dynamic of the restoration of the epithelial barrier integrity during the wound repair process. Airway epithelial cells in culture were chemically wounded by sodium hydroxide. The immunolocalization of zonula occludens 1 (ZO-1), a cytoplasmic protein associated with the tight junctions, was examined during the wound repair process. Junctional integrity was examined by analyzing the transepithelial resistance (TER) and the permeability to [3H]mannitol and by visualizing the permeability to lanthanum nitrate during 5 days after injury. Immediately after injury, we simultaneously observed a 36.7% decrease in the TER and a 74.9% rise in the permeability to [3H]mannitol. In addition, lanthanum nitrate penetrated in the intercellular spaces in the repairing areas, which was also characterized by the absence of ZO-1 staining, as opposed to nonrepairing cells. TER and [3H]mannitol flux values as well as lanthanum nitrate and ZO-1 localizations were found to be similar to those observed in confluent cultures only 1 to 2 days after complete wound closure. This study demonstrates that using our culture model, confluent airway epithelial cells form a continuous and efficient barrier with tight junctions. Epithelial integrity is affected immediately after injury and is completely restored within 1 to 2 days after wound closure. During such a period of time, the airway epithelium may remain exposed to the noxious effect of environment in vivo, which can prevent the epithelial barrier restoration by modifying tight junction formation.

Asialo GM1 is a receptor for Pseudomonas aeruginosa adherence to regenerating respiratory epithelial cells

We investigated the implication of asialo GM1 as an epithelial receptor in the increased Pseudomonas aeruginosa affinity for regenerating respiratory epithelial cells from cystic fibrosis (CF) and non-CF patients. Human respiratory epithelial cells were obtained from nasal polyps of non-CF subjects and of CF patients homozygous for the delta F 508 transmembrane conductance regulator protein (CFTR) mutation and cultured according to the explant-outgrowth model. At the periphery of the outgrowth, regenerating respiratory epithelial cells spreading over the collagen I matrix with lamellipodia were observed, characteristic of respiratory epithelial wound repair after injury. P aeruginosa adherence to regenerating respiratory epithelial cells was found to be significantly greater in the delta F 508 homozygous CF group than in the non-CF group (P < 0.001). In vitro competitive binding inhibition assays performed with rabbit polyclonal antibody against asialo GM1 demonstrated that blocking asialo GM1 reduces P. aeruginosa adherence to regenerating respiratory epithelial cells in delta F 508 homozygous cultures (P < 0.001) as well as in non-CF cultures (P < 0.001). Blocking of asialo GM1 was significantly more efficient in CF patients than in non-CF subjects (P < 0.05). Distribution of asialo GM1 as determined by preembedding labelling and immunoelectron microscopy clearly demonstrated the specific apical membrane expression of asialo GM1 by regenerating respiratory epithelial cells, whereas other cell phenotypes did not apically express asialo GM1. These results demonstrate that (i) asialo GM1 is an apical membrane receptor for P. aeruginosa expressed at the surface of CF and non-CF regenerating respiratory epithelial cells and (ii) asialo GM1 is specifically recovered in regenerating respiratory epithelium. These results suggest that in CF, epithelial repair represents the major event which exposes asialo GM1 for P. aeruginosa adherence.

Expression and localization of CFTR in the rhesus monkey surface airway epithelium

The Rhesus monkey has been used as a model for evaluating the possibility of introducing the CFTR gene into the airway epithelium in vivo. We addressed the question of whether the simian airway surface epithelium exhibits a CFTR distribution and functional activity (ciliary beating frequency) similar to that of human airway surface epithelium. Expression of CFTR mRNA was demonstrated on Rhesus monkey tracheobronchial tissue by reverse transcription polymerase chain reaction (RT-PCR) analysis. By immunofluorescent light microscopy, CFTR was localized on the apical plasma membrane of ciliated cells as we previously described for human tracheobronchial surface epithelium. The ciliary beat frequency (CBF) measured on the explant of Rhesus monkey tracheobronchial tissue appeared to be similar to that of the CBF of human tracheobronchial ciliated cells. To compare the Rhesus monkey CFTR gene with that of the human, we sequenced parts of exon 13 (encoding the R domain) and exon 24 (encoding the C terminal part of the protein) of the Rhesus monkey CFTR gene. The nucleotide sequence identity with the human counterpart was found to be 98% and 94% respectively, although restriction enzyme differences allow discrimination between Rhesus monkey and human CFTR cDNA. Taken together, these results suggest that the airway epithelium of the Rhesus monkey is a suitable model of human respiratory epithelium for analyzing the effect of human CFTR gene transfer.

Glandular-like morphogenesis and secretory activity of human tracheal gland cells in a three-dimensional collagen gel matrix

The extracellular matrix has been demonstrated to affect the differentiation of epithelial cells. We present evidence that in a three-dimensional (3-D) type I collagen gel matrix, isolated human adult tracheal gland (HTG) cells are capable of reconstructing new functional gland-like tubules in vitro. During the first two weeks in culture, HTG cells developed globular epithelial cell aggregates in which lumina is absent. By the third week in culture, the tubulogenesis and the formation of branching structures became evident with a polarized morphology, which in many aspects resembles the in vivo morphology. A central lumen was lined by polarized secretory epithelial cells exhibiting well-developed microvilli and apical secretory granules. Furthermore, we showed that the capacity of in vitro tracheal gland differentiation was associated with the basal deposition of laminin and type IV collagen around the gland-like tubules. A cell-associated 72 kDa type IV collagenase was expressed in developing tubule cells, as shown by immunocytochemistry. The secretion of the antileucoprotease (ALP), a protein marker of tracheal gland serous cells, was bidirectional in gland-like tubules, since up to 65% of released ALP was in the basolateral direction. Taken together, these observations indicate that isolated HTG cells in a 3-D collagen matrix form functional tracheal gland-like tubules and suggest that similar new tracheobronchial gland formations may occur during the human normal gland development and remodeling.

Protection of human respiratory epithelium from Pseudomonas aeruginosa adherence by phosphatidylglycerol liposomes

The ability of phosphatidylglycerol (DSPG) liposomes to prevent adherence of Pseudomonas aeruginosa to primary cultures of non-cystic fibrosis (CF) and delta F508 homozygous CF human respiratory epithelium was studied. The culture model was characterized by the simultaneous presence of various cellular phenotypes: well-differentiated respiratory epithelial cells, ciliated and nonciliated cells, and migrating cells which can be assimilated into a regenerating epithelium after injury. DSPG liposomes significantly decreased the binding of P. aeruginosa to migrating cells of both non-CF and delta F508 homozygous CF cultures compared with control cultures (35.5 x 10(-3) +/- 8.1 x 10(-3) bacteria per micron 2 versus 23.9 x 10(-3) +/- 2.5 x 10(-3); P < 0.01 for non-CF cultures and 88.8 x 10(-3) +/- 17.2 x 10(-3) bacteria per micron 2 versus 29.1 x 10(-3) +/- 0.6 x 10(-3), P < 0.001 for CF cultures). After treatment with DSPG liposomes, the size of P. aeruginosa aggregates bound to migrating cells in both non-CF cultures and delta F508 homozygous CF cultures was significantly decreased (14.4 +/- 3 bacteria per aggregate versus 11.9 +/- 2.5 bacteria per aggregate [P < 0.05] and 29.9 +/- 8.4 bacteria per aggregate versus 17.3 +/- 2.3 bacteria per aggregate [P < 0.01], respectively). Moreover, the control cultures were characterized by a differential P. aeruginosa adherence according to both the cellular phenotype and the mutation. The migrating cells bound more bacteria than the stationary cells of both non-CF and delta F508 homozygous CF cultures. The CF migrating cells bound significantly more bacteria than the non-CF migrating cells (88.8 x 10(-3) +/- 17.2 x 10(-3) bacteria per microns 2 versus 35.5 x 10(-3) +/- 8.1 x 10(-3) bacteria per micron 2, P < 0.001). These results suggest that DSPG liposomes are able to decrease P. aeruginosa adherence to CF and non-CF respiratory epithelium, particularly to migrating cells, which mimic a regenerating epithelium after injury. DSPG liposomes could also represent a hydrophobic barrier limiting the deleterious action of P. aeruginosa exoproducts.

Nasal epithelial cell culture as a tool in evaluating ciliary dysfunction

Cultures of respiratory epithelial cells were obtained from nasal polyps collected in patients with and without primary ciliary defect. The ciliary beating frequency and the ciliary beating heterogeneity were determined on native and cultured tissues. We observed a significantly higher (p < 0.01) ciliary beating frequency of cultured ciliated cells, when compared with ciliated cells from the native tissue. The ciliary beating frequency of the cultured ciliated cells from the patient with primary defect (7.9 +/- 2.1 Hz) was significantly lower when compared with the beating frequency of the ciliated cells from the control subject (12.4 +/- 2.0 Hz). In addition, the percentage of ciliated cells characterized by a beating frequency lower than 8 Hz was 90.7% in the native tissue and 47.5% in the cultured tissue from the patient with ciliary primary defect. In the patient without ciliary primary defect, 90% of the cultured ciliated cells had a homogeneous ciliary beating, whereas in the patient with primary ciliary defect, only 47% of the ciliated cells had a homogeneous ciliary beating. These results suggest that the culture of respiratory cells associated with the functional activity measurement of the ciliated cells represent another way of precisely determining the extent of the primary ciliary dyskinesia defect.

Distearoyl phosphatidylglycerol liposomes improve surface and transport properties of CF mucus

We have previously shown that a decreased level of phosphatidylglycerol in cystic fibrosis (CF) respiratory mucus is partly responsible for its marked adhesiveness and stickiness, which impair mucus transport, and that distearoyl phosphatidylglycerol (DSPG) was the most efficient form of phosphatidylglycerol in the enhancement of respiratory mucus clearance. The aim of our study was to analyse the effect of distearoyl phosphatidylglycerol liposomes on the transport by cough and cilia of cystic fibrosis respiratory mucus. The surface and transport properties of mucus were measured: 1) on native cystic fibrosis mucus; 2) on cystic fibrosis mucus complemented with DSPG liposomes at a non-cytotoxic concentration; and 3) on cystic fibrosis mucus complemented with water. The work of adhesion of cystic fibrosis mucus was significantly decreased by DSPG liposomes, but not by water. For mucociliary transport, the cystic fibrosis mucus was transported at a higher rate with DSPG liposomes and water compared to native cystic fibrosis mucus. The cough clearance of cystic fibrosis respiratory mucus was significantly improved in the presence of DSPG and water, but the effect was more pronounced with DSPG liposomes than with water. We conclude that the use of DSPG liposomes as a lubricating agent proves to be an interesting therapeutic approach for improving the cough and mucociliary transport in cystic fibrosis patients.

Distearoyl phosphatidylglycerol liposomes improve surface and transport properties of CF mucus

We have previously shown that a decreased level of phosphatidylglycerol in cystic fibrosis (CF) respiratory mucus is partly responsible for its marked adhesiveness and stickiness, which impair mucus transport, and that distearoyl phosphatidylglycerol (DSPG) was the most efficient form of phosphatidylglycerol in the enhancement of respiratory mucus clearance. The aim of our study was to analyse the effect of distearoyl phosphatidylglycerol liposomes on the transport by cough and cilia of cystic fibrosis respiratory mucus. The surface and transport properties of mucus were measured: 1) on native cystic fibrosis mucus; 2) on cystic fibrosis mucus complemented with DSPG liposomes at a non-cytotoxic concentration; and 3) on cystic fibrosis mucus complemented with water. The work of adhesion of cystic fibrosis mucus was significantly decreased by DSPG liposomes, but not by water. For mucociliary transport, the cystic fibrosis mucus was transported at a higher rate with DSPG liposomes and water compared to native cystic fibrosis mucus. The cough clearance of cystic fibrosis respiratory mucus was significantly improved in the presence of DSPG and water, but the effect was more pronounced with DSPG liposomes than with water. We conclude that the use of DSPG liposomes as a lubricating agent proves to be an interesting therapeutic approach for improving the cough and mucociliary transport in cystic fibrosis patients.

Studies on human porin. IX. Immunolocalization of porin and CFTR channels in human surface respiratory epithelium

The expression of the voltage-dependent anion channel (VDAC) "Porin 31 HL" and its cellular and subcellular immunocytochemical localization in the human respiratory epithelium were studied with monoclonal and polyclonal antibodies using immunofluorescence and immunogold labelling with light (LM) and transmission electron microscopy (TEM), respectively. Porin was identified in the apical domain of the ciliated cells and in the basal cells of the respiratory epithelium. Immunogold labelling was present in the apical plasma membrane and subapical vesicles of the ciliated cells. In pre-embedded freshly dissociated surface epithelial cells, porin could also be identified with TEM at the outer part of the plasma membrane of basal cells. By LM double immunolabelling, both porin and cystic fibrosis transmembrane conductance regulator (CFTR) were identified in the apical domain of ciliated cells but not in basal cells where CFTR was never identified. On Western blots of solubilized total membrane protein preparations from the same frozen surface epithelial respiratory cells, the antibodies recognized a group of 3 proteins of 31, 60 and 130-140 kDa with a strong reactivity for a 31 kDa protein, corresponding to the porin and a protein of 170 kDa which is consistent with mature CFTR. These results suggest that porin might be part of a multi-component chloride channel complex which could interact with CFTR.

Localization of the cystic fibrosis transmembrane conductance regulator in airway secretory glands

Cystic fibrosis (CF) is caused by mutations in the gene coding for the CF transmembrane conductance regulator (CFTR). From human normal tracheal submucosal gland cells in culture, we identified endogenous CFTR as a 170 kDa protein, consistent with that of fully glycosylated, mature CFTR molecule. This observation led to the hypothesis that airway secretory glands could be an important site for the CFTR expression. Using anti-human CFTR polyclonal and monoclonal antibodies, we examined the cellular and subcellular localization of the CFTR protein in airway submucosal glands from human and bovine tracheal tissues as well as in tracheal gland cell cultures. In human tracheal tissue, CFTR immunolabelling was present along both the apical and basolateral plasma membranes of glandular mucous cells. In contrast, CFTR was associated with the secretory granules of glandular serous cells. Using immunogold electron microscopy, we demonstrated that CFTR protein was more specifically associated with the membrane of serous cell secretory granules. In bovine tracheal tissue CFTR labelling was also identified in the secretory granules of glandular serous cells. In contrast, when bovine and human tracheal gland cells were cultured, no mature secretory granules were present, but a predominantly intracytoplasmic distribution of CFTR was observed. Our data thus suggest that in airway tissues, CFTR could be involved in intracellular processes of the mucus exocytosis in submucosal secretory glands.

Localization of the cystic fibrosis transmembrane conductance regulator in airway secretory glands

Cystic fibrosis (CF) is caused by mutations in the gene coding for the CF transmembrane conductance regulator (CFTR). From human normal tracheal submucosal gland cells in culture, we identified endogenous CFTR as a 170 kDa protein, consistent with that of fully glycosylated, mature CFTR molecule. This observation led to the hypothesis that airway secretory glands could be an important site for the CFTR expression. Using anti-human CFTR polyclonal and monoclonal antibodies, we examined the cellular and subcellular localization of the CFTR protein in airway submucosal glands from human and bovine tracheal tissues as well as in tracheal gland cell cultures. In human tracheal tissue, CFTR immunolabelling was present along both the apical and basolateral plasma membranes of glandular mucous cells. In contrast, CFTR was associated with the secretory granules of glandular serous cells. Using immunogold electron microscopy, we demonstrated that CFTR protein was more specifically associated with the membrane of serous cell secretory granules. In bovine tracheal tissue CFTR labelling was also identified in the secretory granules of glandular serous cells. In contrast, when bovine and human tracheal gland cells were cultured, no mature secretory granules were present, but a predominantly intracytoplasmic distribution of CFTR was observed. Our data thus suggest that in airway tissues, CFTR could be involved in intracellular processes of the mucus exocytosis in submucosal secretory glands.

Differential localization of the cystic fibrosis transmembrane conductance regulator in normal and cystic fibrosis airway epithelium

Deletion of the amino acid residue Phe 508 of the cystic fibrosis transmembrane conductance regulator (CFTR) protein represents the most common mutation identified in cystic fibrosis (CF) patients. A monoclonal and a polyclonal antibody directed against different regions of CFTR were used to localize the CFTR protein in normal and CF airway epithelium derived from polyps of non-CF and CF subjects homozygous for the delta Phe 508 CFTR mutation. To identify the cellular and subcellular localization of CFTR, immunofluorescent light microscopy, confocal scanning microscopy, and immunogold transmission electron microscopy were performed on cryofixed tissue. A markedly different subcellular distribution was identified between normal and CF airway epithelial cells. In normal epithelium, labeling was restricted to the surface apical compartment of the ciliated cells. In contrast, in the epithelium from homozygous delta Phe 508 CF patients, CFTR markedly accumulated in the cytosol of all the epithelial cells. These findings are consistent with the concept that the CFTR delta Phe 508 mutation modifies the intracellular maturation and trafficking of the protein, leading to an altered subcellular distribution of the delta Phe 508 mutant CFTR.

Immunocytochemical analysis reveals differences between the subcellular localization of normal and delta Phe508 recombinant cystic fibrosis transmembrane conductance regulator

Cystic fibrosis (CF) is caused by mutations in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). The most common mutation responsible for CF is the deletion of amino acid residue Phe508, with an average allelic frequency of 70%. We have isolated an anti-CFTR monoclonal antibody which specifically recognizes recombinant normal and delta Phe508-CFTR produced by a vaccinia virus expression system. Immunocytochemical analysis of L cells expressing either normal or delta Phe508-CFTR showed a marked difference in subcellular distribution. Normal CFTR had a distinct localization in the perinuclear area and was also associated with the plasma membrane. delta Phe508-CFTR essentially lacked the membrane-associated distribution and was present throughout the cytoplasm. This heterologous expression system thus provides a model system for studying the subcellular localization of different mutant forms of CFTR.

Identification of phospholipids in secretory granules of human submucosal gland respiratory cells

Although it has been shown that tracheal epithelial cells in culture synthesize and secrete phospholipids, no direct evidence for in situ phospholipid storage in human respiratory secretory epithelial cells has been demonstrated. We used a high-resolution cytochemical enzyme-gold technique to identify and precisely localize phospholipids in human submucosal gland secretory cells. In addition, lysozyme, a specific serous cell marker, was identified using the biotinstreptavidin gold technique with lysozyme antiserum. This double labeling of phospholipids and lysozyme was performed using gold particles of diameters 15 nm and 5 nm, respectively. Quantitation of phospholipid labeling was performed on an image analyzer. Phospholipids were identified in serous granules (8.87 +/- 2.21 gold particles/microns 2) in a significantly (p less than 0.05) higher density than in mucous granules (5.57 +/- 3.07 gold particles/microns 2). These results support the hypothesis that submucosal human airway serous and mucous secretory cells produce phospholipids which may be secreted in the airway lumen.

Functional activity of ciliated outgrowths from cultured human nasal and tracheal epithelia

Primary cultures of respiratory epithelium were produced as outgrowths from human fetal and adult tracheal and nasal polyp explants. Video recordings of the epithelial cell outgrowths were carried out after 5 days of culture and the ciliary beating frequency was analyzed by using a video technique. Uniform fields of differentiated ciliated cells were observed near the edge of the explant. In the transition region of the outgrowth from the explant to the outgrowth periphery, isolated ciliated cells were present, as well as cells with fused cilia. The ciliary beating frequency of the outgrowth of well-differentiated ciliated cells (13.5 +/- 1.4 Hz) was significantly higher (p less than 0.001) than the beating frequency of both the explant (11.9 +/- 0.7 Hz) and the ciliated cells with fused cilia (9.8 +/- 1.7 Hz). The same differentiation stages and functional activities were observed in the outgrowth cultures, whatever their origin. These in vitro models are comparable with each other and therefore could be useful for studying the ciliogenesis and functional activity of the human respiratory epithelium.

Culture and characterization of human tracheal gland cells

In order to study the composition and regulation of human tracheal gland (HTG) cell secretion, we cultured HTG cells isolated by enzymatic digestion from tracheal mucosa obtained 30 to 60 min after death. On microscopic observation, isolated cells were mainly composed of secretory glandular cells. Maximal HTG cell growth was observed when cells were cultured on type I collagen in the presence of 2% Ultroser G. Under these conditions, 3 to 6 HTG cell passages, corresponding to 20 to 30 population doublings, could be achieved. Lysozyme and bronchial inhibitor (Brl), two secretory protein markers specific to the serous HTG cells, were released in the culture medium, maximal secretion being observed 7 days after the cells had reached confluency. At that time, Brl could be detected, with an immunoperoxidase technique, in about 90% of the cells in culture, suggesting that most cells in culture were serous cells. Using transmission electron microscopy, after in situ fixation, HTG cells exhibited an epithelioid appearance at confluency. Using the biotin-streptavidin gold technique, we identified Brl in cytoplasmic vesicles and in small, immature electron-dense secretory granules. In high cell density cultures, we observed dome formation, suggesting active ion transport mechanisms in HTG cell culture. At confluency, a dose-dependent increase of Brl secretion was induced by phenylephrine, isoproterenol, and carbochol. These results suggest that HTG cell culture provides a useful tool to study the biochemistry and regulation of human tracheobronchial gland cell secretion.

Ultrastructural comparative distribution of carbohydrates in human tracheal and frog palate mucosa using neuraminidase and lectin-colloidal gold complexes

We have compared, at the ultrastructural level, the carbohydrate structure of glycoconjugates of the different types of secretory cells of the human tracheal mucosa (HTM) and the frog palate mucosa (FPM), proposed as a model for studying bacterial adherence to mucus-coated respiratory epithelium. In addition to reactivity with Concanavalin A and Lens cullinaris agglutinin, reactivity of Epon-embedded HTM and FPM secretory granules was studied by transmission electron microscopy using neuraminidase-gold complex and colloidal gold-adsorbed lectins with affinity for sugar residues of human mucins, namely the following: Helix pomatia, Lotus tetragonolobus, Ricinus communis II, Wheat germ and Limax flavus agglutinins. The affinity of HTM and FPM mucous and serous cells for the different colloidal-gold complexes was very similar, however Limax flavus agglutinin labelled only HTM and not FPM secretory granules. The FPM mucous and serous secretory granules were nevertheless intensely labelled by the neuraminidase-gold complex, demonstrating the presence of sialic acid residues. The close ultrastructural and histochemical similarities between HTM and FPM suggest that the FPM may be a valuable model for studying the specific interaction between microbial lectins and mucus glycoproteins in the bacterial adherence phenomenon.

Comparative rheological profile of rat gastric and duodenal gel mucus

Methods for measuring the adhesiveness, plasticity, viscoelasticity and spinnability of mucus microsamples have been developed. The rheological properties of the rat gastric and duodenal gel mucus have been analyzed and compared. Using a controlled stress rheometer (Carri-Med), flow and creep experiments showed that gastroduodenal mucus exhibits a typically non-newtonian, pseudoplastic and viscoelastic behaviour. The apparent viscosity (7,800 +/- 11,000 Pa.s) and yield stress (24.9 +/- 8.5 Pa) of gastric mucus were significantly higher than the duodenal mucus viscosity (39 +/- 160 Pa.s) and yield stress (12.9 +/- 2 Pa). Spinnability of gastric mucus, measured with a Filancemeter (SEFAM), was significantly lower (4.9 +/- 2.5 mm) in comparison to duodenal mucus (6.9 +/- 1.5 mm). Adhesive properties of gastric mucosa (analyzed with the platinum ring method) were not significantly different in comparison to duodenal mucus (99.9 +/- 31.5 mN/m and 92.8 +/- 11.2 mN/m, respectively).