Martin Gotteland

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.

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.

Intestinal luminal nitrogen metabolism: Role of the gut microbiota and consequences for the host

Alimentary and endogenous proteins are mixed in the small intestinal lumen with the microbiota. Although experimental evidences suggest that the intestinal microbiota is able to incorporate and degrade some of the available amino acids, it appears that the microbiota is also able to synthesize amino acids raising the view that amino acid exchange between the microbiota and host can proceed in both directions. Although the net result of such exchanges remains to be determined, it is likely that a significant part of the amino acids recovered from the alimentary proteins are used by the microbiota. In the large intestine, where the density of bacteria is much higher than in the small intestine and the transit time much longer, the residual undigested luminal proteins and peptides can be degraded in amino acids by the microbiota. These amino acids cannot be absorbed to a significant extent by the colonic epithelium, but are precursors for the synthesis of numerous metabolic end products in reactions made by the microbiota. Among these products, some like short-chain fatty acids and organic acids are energy substrates for the colonic mucosa and several peripheral tissues while others like sulfide and ammonia can affect the energy metabolism of colonic epithelial cells. More work is needed to clarify the overall effects of the intestinal microbiota on nitrogenous compound metabolism and consequences on gut and more generally host health.

Effect of Lactobacillus ingestion on the gastrointestinal mucosal barrier alterations induced by indometacin in humans

Chronic nonsteroidal anti‐inflammatory drug (NSAID) ingestion strongly affects the gastrointestinal mucosa as a first stage before ulceration. Some Lactobacillus strains may stabilize the mucosal barrier by increasing mucin expression, reducing bacterial overgrowth, stimulating mucosal immunity and synthetizing antioxidant substances; these events are altered in NSAID‐associated gastroenteropathy.

Effect of a Milk Formula With Prebiotics on the Intestinal Microbiota of Infants After an Antibiotic Treatment

Antibiotics exert deleterious effects on the intestinal microbiota, favoring the emergence of opportunistic bacteria and diarrhea. Prebiotics are nondigestible food components that stimulate the growth of bifidobacteria. Our aim was to evaluate the effects on the intestinal microbiota of a prebiotic-supplemented milk formula after an antibiotic treatment. A randomized, double-blind, controlled clinical trial was carried out in 140 infants 1–2 y of age distributed into two groups after a 1-wk amoxicillin treatment (50 mg/kg/d) for acute bronchitis. The children received for 3 wk >500 mL/d of a formula with prebiotics (4.5 g/L) or a control without prebiotics. Fecal samples were obtained on d –7 (at the beginning of the antibiotic treatment), on d 0 (end of the treatment and before formula administration), and on d 7 and 21 (during formula administration). Counts of Bifidobacterium, Lactobacillus-Enterococcus, Clostridium lituseburiense cluster, Clostridium histolyticum cluster, Escherichia coli, and Bacteroides-Prevotella were evaluated by fluorescent in situ hybridization (FISH) and flow cytometry. Tolerance and gastrointestinal symptoms were recorded daily. Amoxicillin decreased total fecal bacteria and increased E. coli. The prebiotic significantly increased bifidobacteria from 8.17 ± 1.46 on d 0 to 8.54 ± 1.20 on d 7 compared with the control 8.22 ± 1.24 on d 0 versus 7.95 ± 1.54 on d 7. The Lactobacillus population showed a similar tendency while the other bacteria were unaffected. No gastrointestinal symptoms were detected during the prebiotic administration. Prebiotics in a milk formula increase fecal bifidobacteria early after amoxicillin treatment without inducing gastrointestinal symptoms.

Modulation of Helicobacter pylori colonization with cranberry juice and Lactobacillus johnsonii La1 in children

OBJECTIVE Probiotics and cranberry have been shown to inhibit Helicobacter pylori in vitro owing to bacteriocin production and high levels of proanthocyanidins, respectively. These effects have been confirmed in clinical trials with H. pylori-positive subjects. The aim of this study was to evaluate whether regular intake of cranberry juice and the probiotic Lactobacillus johnsonii La1 (La1) may result in an additive or synergistic inhibition of H. pylori in colonized children. METHODS A multicentric, randomized, controlled, double-blind trial was carried out in 295 asymptomatic children (6-16 y of age) who tested positive for H. pylori by (13)C-urea breath test (UBT). Subjects were allocated in four groups: cranberry juice/La1 (CB/La1), placebo juice/La1 (La1), cranberry juice/heat-killed La1 (CB), and placebo juice/heat-killed La1 (control). Cranberry juice (200 mL) and La1 product (80 mL) were given daily for 3 wk, after which a second UBT was carried out. A third UBT was done after a 1-mo washout in those children who tested negative in the second UBT. RESULTS Two hundred seventy-one children completed the treatment period (dropout 8.1%). Helicobacter pylori eradication rates significantly differed in the four groups: 1.5% in the control group compared with 14.9%, 16.9%, and 22.9% in the La1, CB, and CB/La1 groups, respectively (P < 0.01); the latter group showed a slight but not significant increase when compared with the other treated groups. The third UBT was carried out only in 19 of the 38 children who tested negative in the second UBT and H. pylori was detected in 80% of them. CONCLUSION These results suggest that regular intake of cranberry juice or La1 may be useful in the management of asymptomatic children colonized by H. pylori; however, no synergistic inhibitory effects on H. pylori colonization were observed when both foodstuffs were simultaneously consumed.

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 13C‐Urea Breath Test (13C‐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 13C‐UBT was carried out at this time. Spontaneous clearance was evaluated in the same way in 81 infected, untreated children. The differences in the δ13CO2 over baseline values before and after treatments (ΔDOB) 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 ΔDOB 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).

Differential protective effects of quercetin, resveratrol, rutin and epigallocatechin gallate against mitochondrial dysfunction induced by indomethacin in Caco-2 cells.

The beneficial effects of dietary polyphenols on health are due not only to their antioxidant properties but also to their antibacterial, anti-inflammatory and/or anti-tumoral activities. It has recently been proposed that protection of mitochondrial function (which is altered in several diseases such as Alzheimer, Parkinson, obesity and diabetes) by these compounds, may be important in explaining the beneficial effects of polyphenols on health. The aim of this study was to evaluate the protective effects of dietary polyphenols quercetin, rutin, resveratrol and epigallocatechin gallate against the alterations of mitochondrial function induced by indomethacin (INDO) in intestinal epithelial Caco-2 cells, and to address the mechanism involved in such damaging effect by INDO, which generates oxidative stress. INDO concentration dependently decreases cellular ATP levels and mitochondrial membrane potential in Caco-2 cells after 20min of incubation. INDO also inhibits the activity of mitochondrial complex I and causes accumulation of NADH; leading to overproduction of mitochondrial O(2)()(-), since it is prevented by pyruvate. Quercetin (0.01mg/ml), resveratrol (0.1mg/ml) and rutin (1mg/ml) protected Caco-2 cells against INDO-induced mitochondrial dysfunction, while no protection was observed with epigallocatechin gallate. Quercetin was the most efficient in protecting against mitochondrial dysfunction; this could be due to its ability to enter cells and accumulate in mitochondria. Additionally its structural similarity with rotenone could favor its binding to the ubiquinone site of complex I, protecting it from inhibitors such as INDO or rotenone. These findings suggest a possible new protective role for dietary polyphenols for mitochondria, complementary of their antioxidant property. This new role might expand the preventive and/or therapeutic use of PPs in conditions involving mitochondrial dysfunction and associated with increased oxidative stress at the cellular or tissue levels.

Pilot study: alterations of intestinal microbiota in obese humans are not associated with colonic inflammation or disturbances of barrier function

Aliment Pharmacol Ther 2010; 32: 1307–1314

Re-print of “Intestinal luminal nitrogen metabolism: Role of the gut microbiota and consequences for the host”

Alimentary and endogenous proteins are mixed in the small intestinal lumen with the microbiota. Although experimental evidences suggest that the intestinal microbiota is able to incorporate and degrade some of the available amino acids, it appears that the microbiota is also able to synthesize amino acids raising the view that amino acid exchange between the microbiota and host can proceed in both directions. Although the net result of such exchanges remains to be determined, it is likely that a significant part of the amino acids recovered from the alimentary proteins are used by the microbiota. In the large intestine, where the density of bacteria is much higher than in the small intestine and the transit time much longer, the residual undigested luminal proteins and peptides can be degraded in amino acids by the microbiota. These amino acids cannot be absorbed to a significant extent by the colonic epithelium, but are precursors for the synthesis of numerous metabolic end products in reactions made by the microbiota. Among these products, some like short-chain fatty acids and organic acids are energy substrates for the colonic mucosa and several peripheral tissues while others like sulfide and ammonia can affect the energy metabolism of colonic epithelial cells. More work is needed to clarify the overall effects of the intestinal microbiota on nitrogenous compound metabolism and consequences on gut and more generally host health.