Transduction pathways regulating the trophic effects of Saccharomyces boulardii in rat intestinal mucosa.

UNLABELLED: Saccharomyces boulardii is a probiotic yeast that is widely prescribed in lyophilized form; it determines several effects in human and rat small intestine including endoluminal secretion of enzymes and of polyamines, stimulation of microvillous enzymes, of sIgA, increased production of the receptor for polymeric immunoglobulins by crypt cells, and enhanced d-glucose uptake. AIM: The objective of this study was to determine the pathway(s) by which these effects generated by the yeast are transduced into mucosal cells. METHODS: Litters of six growing Wistar rats each were treated with S. boulardii (50 microg/gram body weight) or with saline between days 30 and 34 postpartum. For each animal, the cytosol was prepared from the whole mucosa after the fat cake was discarded. Several known intestinal substrates were immunoprecipitated and immunoblotted using specific antibodies recognizing the non-, mono-, or diphosphorylated forms of these substrates. The signals were detected using Echochemiluminoscence (ECL) and were measured by optodensitometry. RESULTS: Treatment with S. boulardii markedly enhanced the RAS-GAP-RAF-ERK(1,2) pathway with participation of growth receptor bound 2 protein, SHC, SOS, and CRKII. Unit p85alpha of phosphatidylinositol 3 kinase, tested in its phosphorylated form, was also enhanced by the probiotic compared to control samples. In rats treated with an inhibitor of RAF-1 and of ERK(1,2) (PD098059) the expression of mucosal disaccharidases was inhibited by about 50%. CONCLUSION: The probiotic S. boulardii generates in vivo mitogen and metabolic signals that are transduced into intestinal mucosal cells, downstream from the apical membrane to the nuclei, using recruitment substrates and serine, threonine, or tyrosine kinases.

Interaction of Saccharomyces boulardii with intestinal brush border membranes: key to probiotic effects?

The probiotic Saccharomyces boulardii exerts beneficial effects in humans, which include trophic effects, anti-inflammatory effects, antisecretory effects, inhibition of toxins, immunostimulatory effects, and resistance to bacterial overgrowth. This short communication discusses the interactions of the probiotic with brush border membrane (BBM) constituents because most of these effects are BBM mediated. The use of bacterial and yeast probiotics has increased dramatically in more and more clinical states, but their exact mechanisms of action remain largely unknown. The present communication focuses on the interactions of a confirmed yeast probiotic (S boulardii) on the constituents of BBMs.

Characterization of alpha,alpha-trehalase released in the intestinal lumen by the probiotic Saccharomyces boulardii.

OBJECTIVE: Trehalose intolerance due to alpha,alpha-trehalase deficiency has scarcely been studied. The purpose of this study was to measure alpha,alpha-trehalase activity in intestinal biopsy samples from 200 consecutive patients over a period of 6 months, and to characterize alpha,alpha-trehalase released by the probiotic Saccharomyces boulardii (S. boulardii). MATERIAL AND METHODS: Enzyme activities were measured in human and rat intestinal mucosal samples using the micromethod of Messer & Dalqvist. alpha,alpha-trehalase from S. boulardii was immunoprecipitated and Western blotted using an IgG purified antibody raised against a 23 amino acid peptide of alpha,alpha-trehalase of S. cerevisiae. RESULTS: Among 200 patients, most of whom complained of abdominal symptoms and diarrhoea, 18 (9%) had total alpha,alpha-trehalase deficiency (0-12 U/g mucosa) and 39 had partial deficiency (3-12 U/g mucosa). Only 4 patients (2%) presented selective alpha,alpha-trehalase deficiency with otherwise normal disaccharidases. Expressed per gram of powder, alpha,alpha-trehalase from S. boulardii delivered in vitro an activity 175 times higher than that of human trehalase per gram of intestinal mucosa. V(max) (22+/-0.43 micromol) and K(m) (5 mM) were close to that of the human enzyme, whereas Western blot revealed a signal of two subunits of 82 kDa. Finally, treatment of rats with S. boulardii resulted in increases in alpha,alpha-trehalase activities of 25 to 45% (p<0.01) in endoluminal fluid and intestinal mucosa compared with in controls. CONCLUSIONS: Our data suggest that alpha,alpha-trehalase deficiency is more common than is believed and that oral administration of S. boulardii could be beneficial in patients with digestive symptoms caused by trehalose intolerance.

Ratio between Epstein-Barr viral load and anti-Epstein-Barr virus specific T-cell response as a predictive marker of posttransplant lymphoproliferative disease.

BACKGROUND: Posttransplant lymphoproliferative disease (PTLD) is closely linked to primary Epstein-Barr virus (EBV) infection and a defect of EBV specific cellular immunity is supposed to be the basis of PTLD. However, EBV load is so far the only marker proposed to evaluate PTLD risk, and no study has investigated the role of specific anti-EBV T lymphocytes (EBV-TL). METHODS: We therefore prospectively measured the EBV-TL by enzyme-linked immunospot (elispot) assay, in correlation to EBV load by real-time quantitative PCR and lymphoproliferation occurrence in 45 liver transplanted children. RESULTS: EBV load at the time of primary infection was high in all patients irrespective to subsequent emergence of PTLD. Seven patients developed PTLD, all of them following primary EBV infection. All seven had low EBV-TL (<2/mm3) associated with high viral load (>25,000 copies/microg DNA). Both parameters can be combined in a 100% positive predictive index. Healing from lymphoma was characterized by rapid EBV-TL increase concomitant to decreasing viral load. EBV-TL follow-up helped to adapt immunomodulation. No patient had PTLD whenever EBV-TL were above 2/mm3. CONCLUSIONS: We conclude that high viral load is systematic in patients who underwent primary EBV infection and is indicative of the PTLD risk only if there is low concomitant cellular immune response. Healing from PTLD requires modulation of immunosuppression, and appearance of EBV-TL.

Hepatocyte transplantation in a 4-year-old girl with peroxisomal biogenesis disease: technique, safety, and metabolic follow-up.

Hepatocyte transplantation is an investigational alternative to orthotopic liver transplantation to treat liver based inborn errors of metabolism. We report successful hepatocyte transplantation in a 4-year-old girl with infantile Refsum disease. Hepatocytes were isolated from the left liver segment of two male donors using a classic two-step perfusion method. Fresh cells were transplanted first and then cryopreserved cells, for a total of 2 billion cells. Total bile acids and abnormal dihydroxycoprostanoïc acid markedly decreased in the patient's serum, indicating resolution of cholestasis and re-population of liver cells. Pipecholic acid decreased by 40% and c26:c22 fatty acid ratio by 36% after 18 months. Donor chromosomes sequences were detected on biopsy posttransplant, indicating engraftment. Hepatocyte transplantation is a safe and promising technique in the treatment of rare inborn errors of metabolism. Future improvements of cell viability and prevention of apoptosis may increase engraftment and subsequent re-population.

Duodenal switch operation for pathologic transpyloric duodenogastric reflux.

OBJECTIVE: To assess the long-term results of the duodenal switch operation made for pathologic transpyloric duodenogastric reflux (DGR). SUMMARY BACKGROUND DATA: DGR symptoms and lesions are poorly responsive to medical treatment. METHODS: A duodenal switch operation was made on 48 patients suffering from pathologic transpyloric DGR either unrelated (n = 28) or secondary (n = 20) to previous upper gastrointestinal (GI) surgery, including cholecystectomy or vagotomy. The diagnosis was based on the combination of several objective arguments: a long history of gastric symptoms (ie, nausea, epigastric pain, and/or bilious vomiting) poorly responsive to medical treatment (48 of 48), gastroesophageal reflux symptoms unresponsive to proton-pump inhibitors (PPI) (23 of 29), gastritis on upper GI endoscopy (37 of 48) and/or at histology (28 of 41), presence of a bilious gastric lake at >1 upper GI endoscopy (30 of 48), DGR at diisopropyl iminodiacetic acid (DISIDA) scintigraphy scanning (7 of 13), pathologic 24-hour intragastric bile monitoring with the Bilitec device (40 of 41), and absence of Helicobacter pylori antral infection (39 of 41). RESULTS: At follow-up (median, 81 months), gastric symptoms were nil, had improved, and remained unchanged in 29 (60.4%), 16 (33.3%), and 2(4.2%) patients, respectively, and 1 patient experienced symptomatic recurrence after a 92-month symptom-free period (2.1%). Among the 44 patients who had postoperative upper GI endoscopy, 42 (95.5%) had no gastritis whereas 5 (11.3%) had an ulcer at the duodenojejunostomy. Gastric exposure to bile at postoperative 24-hour intragastric Bilitec test in 36 patients was nil, within the normal range, and still slightly pathologic in 15 (41.7%), 19 (52.8%), and 2 (5.5%), respectively. CONCLUSIONS: The duodenal switch operation made on patients in whom diagnosis of pathologic transpyloric DGR is supported by several objective arguments provides most of them with symptomatic and endoscopic improvement parallel to abolishment or normalization of gastric exposure to bile. Postoperative PPI therapy during a 2-month period is to be recommended to prevent the development of an anastomotic ulcer.

Effects of Saccharomyces boulardii on intestinal mucosa.

Saccharomyces boulardii (S. boulardii) is a non-pathogenic biotherapeutic agent, widely prescribed in a lyophilized form in many countries over the world. S. boulardii acts as a shuttle liberating effective enzymes, proteins and trophic factors during its intestinal transit that improve host immune defenses, digestion, and absorption of nutrients. In addition, S. boulardii secretes during its intestinal transit polyamines, mainly spermine and spermidine that regulate gene expression and protein synthesis. In this review, we will focus on the interactions of the yeast with the host intestinal mucosa.

Saccharomyces boulardii produces in rat small intestine a novel protein phosphatase that inhibits Escherichia coli endotoxin by dephosphorylation.

Using a polyclonal antibody raised against a highly conserved sequence of 38 amino acids containing the activation site (VTDSAAGAT) common to mammalian and yeast alkaline phosphatases (AP), we identified in decapsidated Saccharomyces boulardii a protein phosphatase detected by autoradiography as a single signal (63 kD). Using an affinity chromatography column, the protein phosphatase could be concentrated 39.1-fold and presented as a doublet of two subunits. Compared with rat and bovine purified intestinal AP, the enzyme from S. boulardii had a greater ability to dephosphorylate the lipopolysaccharide (LPS) of Escherichia coli 055B5. When tested in vivo, intraperitoneal injection of intact LPS to rats produced, after 9 h, 100 ng/mL of circulating tumor necrosis factor-alpha with inflammatory lesions and apoptotic bodies in the liver and the heart, whereas rats injected with partially dephosphorylated LPS produced only 40 ng/mL tumor necrosis factor-alpha without organic lesions. In conclusion, S. boulardii is able to inhibit toxicity of E. coli surface endotoxins by the release of a protein phosphatase exhibiting a great capacity of dephosphorylation.

[Lyophilized Saccharomyces boulardii: example of a probiotic medicine]. / Ejemplo de un medicamento probiótico: Saccharomyces boulardii liofilizada.

Saccharomyces boulardii is a natural yeast without genetic modification isolated from the bark of the litchi tree in Indochina. In its lyophilized form is an example of the called probiotic medicine. The probiotic denomination is in relation to that itself assets in the gastrointestinal tract in interrelation to that biologic environment. And is labelled as medicine because the lyophilized form has a clinical and pharmaceutical expedient included in the regulation of medicinal products in almost 100 countries.

Chronic hepatitis B infection: long term comparison of children receiving interferon alpha and untreated controls.

OBJECTIVES: To investigate the virological outcome of chronic hepatitis B (CH-B) in children who received interferon alpha (IFN) compared with no treatment. METHODS: Seventy-four children with CH-B (median age, 6.1 years; 44 boys) selected from a cohort of 158 cases were included and divided into two groups: IFN-treated (n = 37) and control (n = 37). The controls were matched with the treated children by baseline alanine aminotransferase (ALT) levels, sex and age. The Kaplan-Meier method was performed to estimate the time to clearance of hepatitis B e antigen (HbeAg) and hepatitis B surface antigen (HbsAg). RESULTS: Mean duration of follow-up was comparable in two groups (5.2 +/- 3.8 years in treatment group versus 5.2 +/- 3.7 years in control group, NS). HBeAg and HBsAg loss occurred in 20 (54.1%) and three treated children versus 13 (35.1%) and one untreated children (NS), respectively. The 7-year cumulative HBeAg and HBsAg clearance rates were 47.5% and 8.9% after the first visit in the treatment group versus 33.5% and 4.0% in untreated children (NS), respectively. Elevated baseline ALT (two times upper limit of normal) had a significant effect on the long-term cumulative rate of HBeAg seroconversion in treated patients (P = 0.01) but not in the untreated group. CONCLUSIONS: These findings show that the overall long-term virological outcome does not differ significantly between IFN-treated and untreated children but that a significant benefit of treatment on the long term rate of HBeAg seroconversion is obtained in children with higher baseline ALT levels.

Primary duodenogastric reflux in children and adolescents.

UNLABELLED: Primary duodenogastric reflux is a rare disorder in adults which has not yet been documented in children. Six young patients, aged 4.5 to 16.5 years (median 13.5 years) presented with atypical reflux symptoms persisting from 1 to 84 months (median 8 months) and unresponsive to classical antacid therapy. In all six patients, 24 h gastric bilimetry showed excessive bile exposures for absorbances ranging from 0.25 to 0.60. The fraction of time (supine period) above the 0.25 absorbance threshold ranged from 30% to 75% while the 95th percentile value for healthy adults is 31%. In all patients tested, hepato-iminodiacetic acid scintigraphy revealed the occurrence of a massive duodenogastric reflux and four out of five patients had an alkaline shift (fraction of time pH >8 on 24 h lower oesophageal pH monitoring) ranging from 4.2% to 20% (control values 0.0% to 2.9%). Endoscopic findings included abundant bilious gastric leak (6/6) and chronic prepyloric Helicobacter pylorinegative gastritis (2/6). Daily administration of cisapride, sucralfate with or without omeprazole resulted in an improvement of symptoms in five patients within 15 days. This treatment was ineffective in one patient who became symptom-free only after a surgical duodenal switch with fundoplication was performed. CONCLUSION: primary duodenogastric reflux is a rare foregut disorder of unknown origin occurring in late childhood. If suspected, 24 h intragastric bilimetry appears to be a useful investigation to confirm the diagnosis.

Saccharomyces boulardii enhances N-terminal peptide hydrolysis in suckling rat small intestine by endoluminal release of a zinc-binding metalloprotease.

Saccharomyces boulardii (S. boulardii), a biotherapeutic agent effective in acute and chronic enterocolopathies, produces trophic intestinal effects at least in part mediated by the endoluminal release of polyamines. However, the effects of the yeast on peptide hydrolysis have not yet been studied. The objectives of this study were to assess in suckling rats the endoluminal and mucosal aminopeptidase activities in response to S. boulardii treatment and to analyze their related mechanisms. Peptidase activities were assayed on yeast cells by using several L-amino acid-p-nitroanilide substrates in the pH range of 2 to 10. A marked hydrolytic activity was found for L-leucine-p-nitroanilide that peaked at pH = 8 (K(m) = 0.334 mM, V(max) = 44.7 micromol.min(-1).g(-1) protein). N-terminal peptide hydrolysis was confirmed using as substrate L-Leu-Gly-Gly (K(m) = 4.71 mM, V(max) = 18.08 micromol.min(-1).g(-1) protein). Enzyme reactions were inhibited in the presence of 1 mM Zn(2+). Oral treatment of sucklings with S. boulardii significantly enhanced jejunal and ileal mucosal leucine-aminopeptidase activities by 24 and 34%, respectively, over controls. In concordance, aminopeptidase activity was enhanced in jejunal and ileal endoluminal fluid samples by 47 and 105%, respectively. By use of an IgG-purified antibody raised against the zinc-binding domain common to metalloproteases, the yeast aminopeptidase was immunoprecipitated and detected as an heteromeric enzyme of 108 and 87-kD subunits. S. boulardii, when given orally to suckling rats, is able to significantly enhance hydrolysis of N-terminal oligopeptides in both endoluminal fluid and intestinal mucosa by the endoluminal release of a leucine aminopeptidase that appears to be a zinc-binding metalloprotease belonging to the M1 family of peptidases.

Ontogeny of MAP kinases in rat small intestine: premature stimulation by insulin of BBM hydrolases is regulated by ERKs but not by p-38 MAP kinase.

Although mitogen-activating protein (MAP) kinases are crucial signal transduction molecules regulating cellular proliferation, differentiation, and morphology, their ontogenic changes in the small intestine have not been analyzed. Also, it remains unknown which pathway of activated MAP kinases regulates the expression of brush border membrane hydrolases during growth. Therefore, we have analyzed the mucosal distribution, ontogeny, and responses to insulin and to inhibitors of p44, p42, and p38 MAP kinases in immature and mature enterocytes using Western blot analysis and autoradiography after immunoprecipitation, immunohistochemistry, and in vitro phosphorylation assays. Between d 10 and 40 postpartum, diphosphorylated active p44/p42 extracellular regulated protein kinases (ERKs) increased in abundance compared with total immunoprecipitated ERKs, and were highly responsive to exogenous insulin. In concordance, ERK total activity increased by 4-fold during the same period of growth and was further enhanced 2-fold by exogenous insulin. In weaning rats, ERKs were mainly located in membranes of villus cells and with less intensity in crypt cells. By contrast, p38 MAP kinase was unresponsive to insulin and was confined to nuclei. Administration to sucklings of PD 098059, a specific inhibitor of ERKs, not only inhibited the premature stimulation of sucrase, lactase, and maltase total activities in response to exogenous insulin, but also depressed the natural expression of these brush border membrane enzymes in the absence of insulin stimulation. In concordance, administration of SB 203580, a specific inhibitor of p38 MAP kinase, failed to inhibit both the response of brush border membrane hydrolases to insulin and their natural expression in the absence of insulin stimulation. We conclude that the ontogenic expression of brush border membrane hydrolases and their premature stimulation by insulin are regulated at least in part by the activation of p44/p42 ERKs but not by p38 MAP kinase.

Postcricoid hemangioma: an overlooked cause of dysphagia in infants?-a case report.

Feeding and swallowing disorders in children remain a major challenge owing to a wide differential diagnosis. Hemangioma of the upper aerodigestive tract represents one of the numerous non-neoplastic causes of dysphagia. We report two cases of postcricoid hemangioma causing inhalation and recurrent respiratory infections, treated successfully with systemic corticotherapy alone. To our knowledge, these are the second and third cases described in the literature. After a short review of the literature, the diagnostic procedures are discussed and a management strategy is proposed for this clinical entity, by far underestimated.

Long-term survival and late graft loss in pediatric liver transplant recipients--a 15-year single-center experience.

Increasing numbers of children undergo successful liver transplantation. Limited data exist on long-term survival and late graft loss. Survival and graft loss were studied in 376 primary liver graft recipients who survived more than 3 months after transplantation (80.5% of all primary graft recipients). Patient records were reviewed retrospectively for causes of graft loss. Risk factors were identified by analyzing graft, recipient, and posttransplant variables using multivariate Cox regression. One-, 5-, and 10-year actuarial graft survival rates in the study population were 94.6%, 87.3%, and 86.3%, respectively. Corresponding patient survival rates were 95.7%, 91.4%, and 90.4%. Forty-seven (12.5%) grafts were lost subsequently, 15 by patient death with preserved graft function. Survival rate after late retransplantation was 63.3%. Causes of late graft loss were infection (21.2%), posttransplant lymphoproliferative disease (PTLD, 21.2%), chronic rejection (17%), biliary complications (14.8%), and recurrence of malignant disease (8.5%). Independent risk factors for late graft loss and patient death included liver malignancy as primary disease, steroid resistant rejection, and PTLD. Graft loss rate was significantly increased for reduced-size grafts. Patients undergoing transplantation after 1991 and recipients of full-size grafts were more likely to survive. In conclusion, the long-term outcome for pediatric primary liver graft recipients surviving the early postoperative period is excellent except for patients with liver malignancy. There is no increased risk of late graft loss with the use of split or living related donor grafts. Technical complications are only a minor factor in late graft loss, but complications related to immunosuppression and infection remain a major hazard and must be addressed.