Gastric permeability is not increased in children colonized by CagA-positive strains of Helicobacter pylori

Systematic review: are probiotics useful in controlling gastric colonization by Helicobacter pylori?

Helicobacter pylori is a highly prevalent pathogen considered as an aetiological factor for gastroduodenal ulcers, and a risk factor for gastric adenocarcinoma and lymphoma in humans. Most subjects colonized by this micro-organism are asymptomatic and remain untreated. In symptomatic patients, the antibiotic treatment has a high cost and is not 100% effective because of resistance to antibiotics and to moderate patient compliance. This review discusses the role of probiotics as alternative solutions to assist in the control of H. pylori colonization in at-risk populations. The evidence that some strains of Lactobacillus and Bifidobacterium are able to inhibit H. pylori growth through the release of bacteriocins or organic acids, and may also decrease its adhesion to epithelial cells, is reviewed. In addition, probiotics have a possible role in the stabilization of the gastric barrier function and the decrease of mucosal inflammation. Other aspects that are considered are the contribution of probiotics to the healing of the gastric mucosa linked to their antioxidant and anti-inflammatory properties. Clinical trials in colonized adults and children are reviewed, and suggest that probiotics do not eradicate H. pylori but maintain lower levels of this pathogen in the stomach; in combination with antibiotics, probiotics may increase eradication rate and/or decrease adverse effects. Papers suggesting similar effects on H. pylori by foodstuffs such as berry juice and some milk proteins are quoted. Regular intake of these and other dietary products might constitute a low-cost, large-scale alternative solution applicable for populations at-risk for H. pylori colonization.

Effect of regular ingestion of Saccharomyces boulardii plus inulin or Lactobacillus acidophilus LB in children colonized by Helicobacter pylori

AIM

To evaluate the effect of a probiotic, Lactobacillus acidophilus LB (LB), or a synbiotic, Saccharomyces boulardii plus inulin (SbI), on Helicobacter pylori (Hp) colonization in children.

SUBJECTS AND METHODS

A clinical trial was carried out in a school from a low socio-economic area of Santiago. Two hundred and fifty-four asymptomatic children (8.40+/-1.62 y) were screened for Hp by the (13)C-Urea Breath Test ((13)C-UBT). Hp-positive children were randomly distributed into three groups to receive either antibiotic treatment (lanzoprazole, clarythromycin and amoxicillin) for 8 d, or SbI or LB daily for 8 wk. A second (13)C-UBT was carried out at this time. Spontaneous clearance was evaluated in the same way in 81 infected, untreated children. The differences in the delta(13)CO(2) over baseline values before and after treatments (?DOB) were evaluated.

RESULTS

182 subjects (71.7%) were colonized by Hp, and 141 of them completed their treatment (22.5% dropout). Hp was eradicated in 66%, 12% and 6.5% of the children from the Ab, SbI and LB groups, respectively, while no spontaneous clearance was observed in the children without treatment. A moderate but significant difference in ?DOB was detected in children receiving living SbI (-6.31; 95% CI: -11.84 to -0.79), but not in those receiving LB (+0.70; 95% CI: -5.84 to +7.24).

CONCLUSION

S. boulardii seems promising as an agent that interferes with Hp in colonized individuals. More studies are needed to confirm these results and to elucidate the mechanisms by which Sb inhibits Hp.

Effect of Lactobacillus GG on intestinal integrity in Malawian children at risk of tropical enteropathy

BACKGROUND

Tropical enteropathy is an asymptomatic villous atrophy of the small bowel that is prevalent in the developing world and is associated with altered intestinal function and integrity. The histology of tropical enteropathy resembles that seen in small-bowel bacterial overgrowth.

OBJECTIVE

This study tested the hypothesis that treatment of 3-5-y-old Malawian children with the probiotic Lactobacillus GG would improve their intestinal function and integrity.

DESIGN

Clinically healthy children (n = 164) were enrolled in a placebo-controlled, randomized, double-blind trial. Intestinal function and integrity were measured by using the site-specific sugar-absorption test before and after 30 d of treatment with Lactobacillus GG or placebo. The primary outcomes were the ratios of urinary lactulose to mannitol (L:M) and of urinary sucrose to lactulose (S:L) excretion.

RESULTS

Of the 161 children who completed the study, 119 (73%) had tropical enteropathy on enrollment (L:M > 0.10). Children receiving Lactobacillus GG did not differ significantly from the placebo group in the excretion (in % of dose administered) of mannitol (mean +/- SD: 8.9 +/- 4.4 and 8.9 +/- 3.9, respectively), lactulose (0.31 +/- 0.20 and 0.33 +/- 0.23, respectively), or sucrose (0.078 +/- 0.058 and 0.082 +/- 0.075, respectively). L:M and S:L also did not differ significantly between the Lactobacillus and placebo groups (0.19 +/- 0.13 and 0.20 +/- 0.12, respectively, for L:M; 0.58 +/- 0.46 and 0.65 +/- 0.57, respectively, for S:L).

CONCLUSION

Administration of Lactobacillus GG for 30 d had no effect on the intestinal integrity of 3-5-y-old Malawian children.

Helicobacter pylori and specific immunoglobulin E antibodies to food allergens in children

OBJECTIVES

It has been suggested that chronic Helicobacter pylori infection may increase gastric permeability, predisposing infected children for the development of food allergies. We assessed the presence of food-specific immunoglobulin (Ig)E antibodies in H. pylori positive children and controls.

METHODS

We measured specific IgE values to six major food allergens (Pharmacia CAP-system) in a group of school-aged Caucasian (n = 36) and non-Caucasian (n = 38) children with a known H. pylori status. All children had undergone upper gastrointestinal endoscopy because of abdominal complaints.

RESULTS

Among H. pylori positive children (mean age, 8.8 years; range, 5-15 years, 25 female, 26 male), 33% (17 of 51) had an elevated food-specific IgE level to at least one of the food allergens tested. Unexpectedly, the majority of those with elevated serum food-specific IgE levels (12 of 17) were to cow's milk. Among H. pylori negative children (mean age, 9.3 years; range, 5-15 years, 13 female, 10 male), 26% (6 of 23) of the children had an elevated serum IgE level to at least one of the food allergens tested, and 9% (2 of 23) were positive to cow's milk. The difference in the number of children with an elevated serum IgE level for cow's milk in H. pylori positive and negative children was not significant. The severity of gastritis did not correlate with the presence of food-specific IgEs.

CONCLUSIONS

H. pylori infection had no effect on the manifestation of specific IgE to major food allergens in school-aged children. An IgE response to cow's milk was common among these school-aged children.

Helicobacter pylori increases the epithelial permeability to a food antigen in human gastric biopsies

AIMS

We have previously shown that H. pylori increases the passage of intact protein across the digestive epithelium, in vitro and in vivo in mice. The aim of this study was to test whether H. pylori can alter gastric permeability to a food-type antigen in humans.

METHODS

Antral and corpus gastric biopsies obtained from H. pylori-positive and H. pylori-negative patients suffering from nonulcer dyspepsia with normal esogastroduodenal endoscopy were mounted in adapted Ussing chambers to measure gastric permeability. Electrical resistance (R, an index of epithelial integrity) and fluxes of 14C-mannitol (JMan, a marker of paracellular permeability) and 3H-horseradish peroxidase (HRP, a test protein of antigen transport and processing) under intact (JHRPi) and degraded (JD) form, across the biopsies, were measured.

RESULTS

At the corpus level, biopsies obtained from H. pylori-positive patients, as compared to H. pylori-negative patients, presented significantly higher intact--but not degraded--HRP fluxes (JHRPi = 446 +/- 297 and 219 +/- 265 ng/h cm2, p < 0.05; JD = 4,247 +/- 3,884 and 3,575 +/- 2,594 ng/h x cm2, respectively), and an increase in paracellular permeability (Jman = 0.35 +/- 0.1 vs 0.24 +/- 0.08 micromol/h x cm2, p < 0.02, respectively). At the antrum level, a tendency to increased intact HRP fluxes in H. pylori-positive patients, as compared to H. pylori-negative patients, was observed (JHRPi = 284 +/- 250 vs 207 +/- 203 ng/h x cm2, p < 0.09), without modifications of paracellular permeability.

CONCLUSIONS

H. pylori infection increases absorption of an intact food antigen across the corpus gastric mucosa. This phenomenon may contribute to the maintenance of gastric inflammation and could play a role in the development of allergic sensitization to dietary antigens in susceptible individuals.

Construction and expression of the fusion gene of H pylori HspA subunit and E.coli heat-labile enterotoxin B subunit

AIM

To construct and express the fusion gene of H pylori heat shock protein A subunit (HspA) and E.coli heat-labile enterotoxin B subunit (LTB), and analyse the biologic and immunologic characteristics of the fusion protein.

METHODS

HspA gene was amplified from H pylori chromosome by PCR. The gene was cloned into plasmid pPLtB and the fusion gene of H pylori urease B subunit (HspA) and E.coli heat-labile enterotoxin B subunit (LTB) was constructed, and then LTB-HspA recombinant protein was expressed in E.coli JM109.

RESULTS

LtB-HspA fusion gene was found to be 684 base pairs and encode the recombinant fusion protein, which was composed of 228 amino acid residues. SDS-PAGE and Western blotting analysis showed that the recombinant fusion protein had a molecular weight of 25kD and a positive reaction with the serum from H pylori-infected patients. ELISA analysis showed that LTB protein existed in the fusion protein. At the same time, fusion protein kept the character of binding with LTB receptor-ganglioside GM1.

CONCLUSION

LTB-HspA recombinant protein may be used for research of genetically engineered H pylori vaccine.

Effect of the ingestion of a dietary product containing Lactobacillus johnsonii La1 on Helicobacter pylori colonization in children

OBJECTIVES

Dietary components such as vegetable or probiotic microorganisms have been proposed as an alternative solution to decrease Helicobacter pylori colonization in at-risk populations. Some strains of lactic acid bacteria have been shown to exert bacteriostatic or bactericidal effects against H. pylori in in vitro and in vivo models of infection by this pathogen. We investigated whether regular ingestion of a dietary product containing Lactobacillus johnsonii La1 or L. paracasei ST11 would interfere with H. pylori colonization in children.

METHODS

A double blind, randomized, controlled clinical trial was carried out in school children from a low socioeconomic area of Santiago. Subjects were 326 asymptomatic children (9.7 +/- 2.6 y) screened for H. pylori by the (13)C-urea breath test; H. pylori-colonized subjects were distributed into five groups to receive a product containing live La1 or ST11 (groups 1 and 3), heat-killed La1 or ST11 (groups 2 and 4), or vehicle (group 5) everyday for 4 wk. A second (13)C-urea breath test was carried out at the end of this period. Differences in delta(13)CO(2) above baseline values before (DOB1) and after (DOB2) probiotic treatment were evaluated.

RESULTS

A high prevalence of H. pylori colonization, 77.3%, was observed in our population. A moderate but significant difference (DOB2 - DOB1) was detected in children receiving live La1 (-7.64 per thousand; 95% confidence interval, -14.23 to -1.03), whereas no differences were observed in the other groups. The magnitude of the decrease in DOB values induced by La1 ingestion correlated with the basal values of DOB before treatment (r = 0.48, P = 0.0074).

CONCLUSIONS

Regular ingestion of a product containing Lactobacillus La1 may represent an interesting alternative to modulate H. pylori colonization in children infected by this pathogen.

Effect of acute cigarette smoking, alone or with alcohol, on gastric barrier function in healthy volunteers

BACKGROUND

Smoking is a risk factor for gastroduodenal ulcer and gastric adenocarcinoma. However, the pathophysiological mechanisms induced by acute cigarette smoking in the human gastric mucosa are poorly understood.

AIM

To evaluate the effect of acute cigarette smoking, alone or with alcohol, on the gastric permeability to sucrose, a specific marker of mucosal damage in the stomach.

SUBJECTS AND METHODS

Twenty healthy volunteers (8 smokers/12 non-smokers) were studied. Each fasted subject ingested 500 ml of a 20% sucrose solution and the amount of sucrose excreted in a 5-hour urine collection was measured by gas chromatography Four sucrose permeability tests were carried out: 1. basal, 2. while smoking 5 cigarettes, 3. after drinking 50 ml of a 40 degrees alcoholic beverage, 4. a combination of 2+3.

RESULTS

Sucrose excretion increased after alcohol ingestion (40.5 +/- 6.0 mg vs 143.1 +/- 28.9 mg, p = 0.002), but was not modified by acute cigarette smoking (34.4 +/- 5.9 mg). When alcohol and cigarettes were simultaneously consumed, the increase in alcohol-induced sucrose excretion was significantly reduced (73.1 +/- 16.6 mg, p = 0.03). Basal sucrose excretion was similar in smokers and non-smokers. However, in acute cigarette smoking, a decrease in sucrose excretion was observed in smokers (p = 0.02) but not in non-smokers.

CONCLUSIONS

These results indicate that acute cigarette smoking may tighten the gastric mucosa in habitual smokers and this is associated with a smaller increase of gastric permeability induced by alcohol.