Studies of the pH Gradient Across the Mucus on Rat Gastric Mucosa in Vivo and Across Mucus on Human Gastric Mucosa In Vitro

A novel animal model for studying antibiotic transfer across gastric mucosa was developed by using adult rats. Gastric corpus mucosa was mounted in an Ussing chamber system and bathed in oxygenated Krebs solution. Metronidazole flux from serosa to mucosa (J(S-->M)) was measured over 60 min under basal conditions and compared with mucosa-to-serosa flux (J(M-->S)). The effects of varying the chamber cross-sectional diameter and of stimulation by histamine and carbachol were assessed. Metronidazole J(M-->S) was measured with the mucosal pH at 2.2, 2.7, 3.2, and 7.4. Amoxicillin J(S-->M) under basal conditions was also measured and compared with metronidazole J(S-->M). Metronidazole J(S-->M) was proportional to serosal concentration (P < 0.001) under basal conditions, being 3.98 nmol x h(-1) x cm(-2) with a serosal concentration of 0.2 mmol/liter. Amoxicillin J(S-->M) was significantly lower under similar conditions at 0.50 nmol x h(-1) x cm(-2) (P < 0.01). Metronidazole J(S-->M) was not significantly different from J(M-->S), between chambers of different sizes, or following stimulation. When the mucosal pH was changed, J(M-->S) was proportional to the un-ionized concentration on the mucosal side (P < 0.001). Therefore, this model shows properties analogous to those of human gastric mucosa in vivo, with partitioning of metronidazole on the mucosal side according to pH, diffusion of metronidazole across the mucosa in both directions, and selectivity for different antibiotics, and it will be useful for the study of other therapeutic agents in the treatment of Helicobacter pylori.

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Living cells of probiotic Bifidobacterium bifidum YIT 10347 detected on gastric mucosa in humans

Beneficial Microbes ◽

10.3920/bm2015.0138 ◽

2016 ◽

Vol 7 (3) ◽

pp. 319-326 ◽

Cited By ~ 5

Author(s):

H. Shibahara-Sone ◽

A. Gomi ◽

T. Iino ◽

M. Kano ◽

C. Nonaka ◽

...

Keyword(s):

Gastric Mucosa ◽

Human Study ◽

In Vitro Study ◽

Probiotic Strain ◽

Bifidobacterium Bifidum ◽

Human Gastric Mucosa ◽

Beneficial Effects ◽

H Pylori

The probiotic strain Bifidobacterium bifidum YIT 10347 has been demonstrated to inhibit Helicobacter pylori activity, prevent injury to the gastric mucosa, and improve general gastric malaise symptoms in H. pylori positive patients. This study aimed to investigate the adhering activity and localisation of B. bifidum YIT 10347 to gastric cells and tissue in vitro, and in human in vivo to clarify the mechanism of its beneficial effects on the stomach. The in vitro study found the adhesion rate of B. bifidum YIT 10347 to human gastric epithelial cells was about 10 times higher than that of lactic acid bacteria and other bifidobacteria. In the human study, 5 H. pylori negative and 12 H. pylori positive subjects ingested milk fermented with B. bifidum YIT 10347. B. bifidum YIT 10347 cells were measured by RT-qPCR for in gastric biopsy samples. Living B. bifidum YIT 10347 cells were detected in the biopsy samples in H. pylori negative subjects (105 cells/g and 104 cells/g at 1 h and 2 h after ingestion, respectively) and H. pylori positive subjects (104 cells/g at 1 h after the ingestion). Moreover, immunostaining analysis of tissue sections found that B. bifidum YIT 10347 cells were located at the interstitial mucin layer of the stomach. These results suggest that cells of probiotic B. bifidum YIT 10347 adhered to the human gastric mucosa in a live state, and that the higher adhering activity of B. bifidum YIT 10347 to the gastric mucosa may be involved in its beneficial effects on the human stomach.

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Variations in Helicobacter pylori Lipopolysaccharide To Evade the Innate Immune Component Surfactant Protein D

Infection and Immunity ◽

10.1128/iai.73.11.7677-7686.2005 ◽

2005 ◽

Vol 73 (11) ◽

pp. 7677-7686 ◽

Cited By ~ 38

Author(s):

Wafa Khamri ◽

Anthony P. Moran ◽

Mulugeta L. Worku ◽

Q. Najma Karim ◽

Marjorie M. Walker ◽

...

Keyword(s):

Helicobacter Pylori ◽

Gastric Mucosa ◽

Phase Variation ◽

Surfactant Protein ◽

Clinical Isolates ◽

Surfactant Protein D ◽

Human Gastric Mucosa ◽

H Pylori

ABSTRACT Helicobacter pylori is a common and persistent human pathogen of the gastric mucosa. Surfactant protein D (SP-D), a component of innate immunity, is expressed in the human gastric mucosa and is capable of aggregating H. pylori. Wide variation in the SP-D binding affinity to H. pylori has been observed in clinical isolates and laboratory-adapted strains. The aim of this study was to reveal potential mechanisms responsible for evading SP-D binding and establishing persistent infection. An escape variant, J178V, was generated in vitro, and the lipopolysaccharide (LPS) structure of the variant was compared to that of the parental strain, J178. The genetic basis for structural variation was explored by sequencing LPS biosynthesis genes. SP-D binding to clinical isolates was demonstrated by fluorescence-activated cell sorter analyses. Here, we show that H. pylori evades SP-D binding through phase variation in lipopolysaccharide. This phenomenon is linked to changes in the fucosylation of the O chain, which was concomitant with slipped-strand mispairing in a poly(C) tract of the fucosyltransferase A (fucT1) gene. SP-D binding organisms are predominant in mucus in vivo (P = 0.02), suggesting that SP-D facilitates physical elimination. Phase variation to evade SP-D contributes to the persistence of this common gastric pathogen.

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Actions of prostacyclin (PGI2) and its product, 6-oxo-PGF1α on the rat gastric mucosa in vivo and in vitro

Prostaglandins ◽

10.1016/0090-6980(78)90038-2 ◽

1978 ◽

Vol 15 (6) ◽

pp. 955-967 ◽

Cited By ~ 128

Author(s):

B.J.R. Whittle ◽

N.K. Boughton-Smith ◽

S. Moncada ◽

J.R. Vane

Keyword(s):

Gastric Mucosa ◽

Rat Gastric Mucosa

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Biosynthesis of proteins by human gastric mucosa in vitro

Biochemical Journal ◽

10.1042/bj2420339 ◽

1987 ◽

Vol 242 (2) ◽

pp. 339-346 ◽

Cited By ~ 4

Author(s):

M Spohn ◽

I McColl

Keyword(s):

Gastric Mucosa ◽

Polyacrylamide Gel Electrophoresis ◽

Deae Cellulose ◽

Ion Exchange Chromatography ◽

Exchange Chromatography ◽

Human Gastric Mucosa ◽

Tissue Incorporation ◽

Mucus Glycoproteins

Incorporation of L-[U-14C]leucine and of D[U-14C]glucose into proteins of fresh human gastric mucosa in vitro was studied after incubation of homogenized tissue and of intact mucosal pieces. CsCl centrifugation was used to separate high-density mucus glycoproteins from other mucosal proteins, and the macromolecular nature of radioactive mucosal glycoprotein fractions was confirmed by SDS/polyacrylamide-gel electrophoresis and autoradiography of the polyacrylamide gels. In all experiments a substantial proportion of total incorporated radioactivity was associated with gastric-mucosal glycoprotein fractions (CsCl fraction L3), indicating their biosynthesis. Radioactivity of these fractions was shown to co-chromatograph with carbohydrates when fractionated either directly or after reduction and alkylation (1) Sephadex G-200 chromatography in the excluded fractions and (2) by DEAE-cellulose ion-exchange chromatography. On incubation of intact mucosa, the major portion of radioactivity associated with the glycoprotein fractions of both leucine- and glucose-labelled specimens was secreted into the mucosal media during the course of the experiment. It is suggested that biosynthesis of mucus in vivo by gastric mucosa may be associated with rapid secretion of the synthesized macromolecules into the lumen of the stomach and that investigations of the metabolic processes within the mucosa should consider the products of secretion of the tissue. Incorporation of L-[U-14C]leucine implies biosynthesis of the polypeptide components of the macromolecules.

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