The role of rectal chloride secretion in childhood constipation.

BACKGROUND: Disturbance in fluid secretion, driven by chloride secretion, might play a role in constipation. However, disturbed chloride secretion in those patients has yet to be evaluated. Therefore, the aim of this study was to compare chloride secretion in rectal biopsies of children with functional constipation (FC) to those without constipation. METHODS: To measure changes in short circuit current (I(sc) in µA cm(-2)) reflecting chloride secretion, intestinal biopsies from children with constipation, to either exclude or diagnose Hirschsprung's disease, and from children without constipation (controls) undergoing colonoscopy for screening of familial adenomatous polyposis, juvenile polyps or inflammatory bowel disease (IBD), were compared and studied in Ussing chambers. Following electrogenic sodium absorption blockade by amiloride, chloride secretory responses to calcium-linked (histamine, carbachol) and cAMP-linked (IBMX/forskolin) secretagogues were assessed. KEY RESULTS: Ninety-six patients (46 FC) participated; nine FC patients (n = 1 congenital syndrome and n = 8 technical problems) and 13 controls (n = 6 IBD; n = 7 technical problems) were excluded. No significant difference was found in mean (±SE) basal chloride currents between children with FC and controls (9.6 ± 1.1 vs 9.2 ± 0.8; P = 0.75, respectively). Responses to calcium-linked chloride secretagogues (histamine and carbachol) were significantly higher in controls (33.0 ± 3.0 vs 24.5 ± 2.3; P = 0.03 and 33.6 ± 3.4 vs 26.4 ± 2.7; P = 0.05 following histamine and carbachol, respectively). CONCLUSIONS & INFERENCES: Calcium-linked chloride secretion is disturbed in children with FC. Whether this defect occurs at the level of histamine receptors, components of receptor-linked signal transduction pathways or basolateral Ca(2+) -sensitive K(+) channels enhancing the electrical driving force for apical chloride secretion, remains to be explored.

Short-chain fatty acids and commensal microbiota in the faeces of severely malnourished children with cholera rehydrated with three different carbohydrates.

BACKGROUND: Short-chain fatty acids (SCFAs) liberated by fermentation of complex carbohydrates might stimulate water and salt absorption, and provide energy. The aim of the study was to assess the number and proportion of faecal bacteria and the concentration of SCFAs of severely malnourished children with cholera receiving oral rehydration solution (ORS) containing glucose, amylase-resistant starch (ARS) or rice. METHODS: Serial faecal samples were collected from 30 malnourished children with cholera until rehydration and partial nutritional recovery. SCFAs were identified and quantitated by high-performance liquid chromatography. In situ hybridization combined with flow cytometry was used to analyse the microbiota in the faeces. RESULTS: Before treatment the concentration of total SCFA in faecal sample of cholera children was found to be 4.7±0.6 mmol/kg and it increased steadily until 95.0±8.7 mmol/kg at day 28. Among different ORS groups, concentration was significantly higher in the Rice-ORS group at day 1 (P<0.011) and at day 2 (P<0.025). During recovery faecal output was significantly reduced and the number of bacteria also increased faster in the Rice-ORS group than in the glucose-ORS group at day 1 and day 2 (P<0.01), and a modest increase in bacterial number was observed in the glucose-ORS plus ARS group (day 1, P=0.07; day 2, P=0.09). CONCLUSION: Clinical recovery was associated with an increase in bacterial and SCFA concentrations with all three carbohydrates in ORS. However, the increases were significantly higher in children receiving Rice-ORS.

Effect of feeding yogurt versus milk in children with acute diarrhea and carbohydrate malabsorption.

BACKGROUND: The aim of this study was to compare the effect of infant formula and the same formula subjected to microbial fermentation (yogurt) on the duration of diarrhea in young children with acute watery diarrhea, with or without reducing substances in stools. METHODS: One hundred twelve well-nourished children, aged 3 to 24 months, who were admitted to the hospital with acute watery diarrhea were included in a randomized trial. After appropriate rehydration, they were fed either an infant formula (group M, n = 56) or the same formula fermented with Lactobacillus bulgaricus and Streptococcus thermophilus (group Y, n = 56). The two feedings were comparable in lactose concentration (40 to 42 g/L), pH 4.5, flavor, and texture. The groups were subdivided into those with or without reducing sugars in stools at presentation. The presence of reducing sugars in stool was used as a marker of carbohydrate malabsorption. RESULTS: Group M and group Y had comparable clinical characteristics at admission, including the number of patients with reducing sugars in stools (n = 31 in group M and 27 in group Y). The success rate (cessation of diarrhea and appropriate weight gain 7 days after enrollment into the study) was similar in both groups (82% in group M vs. 84% group Y). Clinical failure was 3.6% in both groups. The percentage of patients withdrawn from the study for medical reasons (5.4% in group M vs. 7.1% in group Y) or withdrawn at the parents' request (8.9% in group M vs. 5.4% in group Y) was similar. Duration of diarrhea and number of stools were significantly less in group Y compared with group M. Forty-eight hours after inclusion, diarrhea was still present in 62% of group M versus in 35% of group Y (P < 0.002). In children with reducing sugars in stools, the rate of success (82%) was similar in groups M and Y, but the duration of diarrhea and number of stools per day were significantly decreased in group Y. Forty-height hours after inclusion, diarrhea was still present in 75% of group M patients and in 20% of group Y patients who had reducing substances in the stool. CONCLUSION: Young children with acute watery diarrhea, without malnutrition or associated disease, can be equally well treated with feeding of either infant formula or yogurt. Yogurt feeding is associated with a clinically relevant decrease in stool frequency and duration of diarrhea in children who have reducing sugars in stools.

Effect of cholera toxin on glutamine metabolism and transport in rabbit ileum.

The aim of the present study was to evaluate the effect of cholera toxin on energy balance from intestinal glutamine metabolism and oxidation, glutamine-dependent sodium absorption, and cholera toxin-dependent ion flux. Cholera toxin-stimulated sodium and L-glutamine ileal transport and metabolism were studied in Ussing chambers. Glutamine (10 mM) transport and metabolism were simultaneously studied using (14)C flux and HPLC. In the same tissues, the flux of each amino acid was studied by HPLC, and glutamine metabolism and oxidation were studied by the determination of amino acid specific activity and (14)CO(2) production. In control tissues, glutamine stimulated sodium absorption and was mainly oxidized. The transepithelial flux of intact glutamine represented 45% of glutamine flux across the luminal membrane. The other metabolites were glutamate and, to a lesser degree, citrulline, ornithine, and proline. Cholera toxin did not alter glutamine-stimulated sodium absorption, glutamine oxidation, transport, and metabolism. In conclusion, the present results indicate that cholera toxin does not alter glutamine intestinal function and metabolism. In addition, approximately 95% of the energy provided by glutamine oxidation remains available to the enterocyte.

Cytokine-induced alteration of the epithelial barrier to food antigens in disease.

The alteration of the intestinal epithelial barrier is often a consequence of various intestinal diseases but may also be the starting point of these diseases. Undigested food antigens are transported across the intestinal epithelium by a transcytotic mechanism, including a processing within the enterocytes, and leading to the passage of intact proteins, peptides, and amino acids to the underlying mucosa. Inflammation and infection lead to the upregulation of the transport and processing of food proteins; for example, IFN gamma increases the rate of transcytosis and alters, like TNF alpha, the tight junction permeability. Infection of gastric digestive epithelia with Helicobacter pylori also increases the antigenic load transmitted to the underlying immune system by inhibiting the enterocytic lysosomal degradation of proteins. In allergic diseases, such as cow's milk allergy, TNF alpha may be involved in the intestinal dysfunction and the associated enteropathy.

Sacolene in cholera: a double blind randomized controlled trial.

Methylated casein (Sacolene), a diarrhoea remedy used in Europe, has shown an antisecretory effect in cholera-induced secretion in animals and benefit in diarrhoea in humans. In this placebo controlled trial Sacolene was evaluated in 78 male adults with severe cholera who, after initial i.v. therapy received Sacolene or placebo, 4 g at start and 2 g 4 hourly until cessation of diarrhoea, along with oral rehydration therapy and repeat i.v. therapy if indicated. No antibiotics were given during the study. The purging rate and diarrhoea duration were similar in the 2 groups. The proportion of patients requiring repeat courses of i.v. therapy in the study group was 46% compared with 69% in controls (i.e. reduced by 23%, p = 0.04). While the severity of purging was not reduced, the proportion of patients requiring repeat i.v. therapy was reduced by Sacolene therapy. The latter finding may indicate some benefit from Sacolene in cholera, though this requires confirmation.

Effect of sorbin on electrolyte transport in rat and human intestine.

Stimulating water absorption in the colon represents an important target to reduce stool output in secretory diarrhea. Recently, a 153-amino-acid peptide was isolated from porcine upper small intestine and purified, taking into account the increase of water absorption in guinea pig gallbladder. Accordingly, this peptide was named sorbin. The aim of the present study was to determine if the COOH-terminal heptapeptide of sorbin (C7-sorbin) participates in the regulation of electrolyte transport in the colon. Different regions (from duodenum to colon) of stripped intestinal mucosa from rats or humans were mounted in Ussing chambers to measure the changes in short-circuit current (DeltaIsc) and net 22Na and 36Cl fluxes (JNanet and JClnet) after serosal exposure of 10(-7) to 10(-3) M C7-sorbin. In fasted rat intestine, C7-sorbin (10(-4) M) induced an immediate reduction in Isc in the distal ileum and proximal and distal colon but not in the duodenum and jejunum. In the colon, Isc reduction and JNanet and JClnet stimulation were dose dependent (EC50 = 2 x 10(-5) M). At 10(-3) M, maximal effect was observed (DeltaIsc = -1.14 +/- 0.05, DeltaJNanet = +4.97 +/- 1.38, and DeltaJClnet = +9.25 +/- 1.44 microeq. h-1. cm-2). C7-sorbin (10(-3) M) inhibited the increase in Isc induced by a series of 10 secretory agents such as secretin, vasoactive intestinal peptide, PGE2, and serotonin. In HT-29-Cl19A cells, C7-sorbin induced an increase in Isc, with a maximal effect at 10(-3) M (DeltaIsc = 0.29 +/- 0.10 microeq. h-1. cm-2). In human intestine, a dose-dependent decrease in Isc was observed in right and sigmoid colons in basal and stimulated conditions (EC50 congruent with 10(-5) M; at 10(-4) M, DeltaIsc = -2.66 +/- 0.17 microeq. h-1. cm-2) but not in the jejunum. The results indicate that C7-sorbin stimulated NaCl neutral absorption and inhibited electrogenic Cl- in rat and human intestinal epithelia. In addition, the antisecretory effect was essentially observed in the distal part of both rat and human intestine and the magnitude of the proabsorptive effect was directly related to the magnitude of the previously induced secretion.

Antral gastric permeability to antigens in mice is altered by infection with Helicobacter felis.

OBJECTIVE: Gastric inflammation is observed not only during Helicobacter pylori infection but also after eradication of the bacterium. The hypothesis that an altered gastric permeability could be involved was tested using a model of mice infected with Helicobacter felis. DESIGN: The antral and corpus gastric permeability during infection and after eradication of bacteria was studied. METHODS: Gastric fragments from the antrum and corpus of healthy mice, mice infected with H. felis, or mice after bacterial eradication, were mounted in Ussing chambers, and fluxes of sodium (JNa), mannitol (JMan) and horseradish peroxidase (HRP) under intact (JHRPi) and degraded (JD) form were measured. RESULTS: In healthy mice, JNa, JMan, JHRPi and JD, respectively, were greater in the antrum (6.5 +/- 0.5 microEq/h.cm2; 0.137 +/- 0.016 micromol/h.cm2; 30.4 +/- 7.4 ng/h.cm2 and 852 +/- 173 ng/h.cm2) than in the corpus (5.0 +/- 0.3 microEq/h.cm2; 0.085 micro 0.013 micromol/h.cm2; 9.5 +/- 2.8 ng/h.cm2 and 434 +/- 139 ng/h.cm2). In H. felis-infected mice, HRP fluxes in the antrum were increased (JHRPi = 182 +/- 86, JD = 948 +/- 94 ng/h.cm2) as compared to controls (JHRPi = 10.3 +/- 2.6, JD = 458 +/- 98 ng/h.cm2). Bacterial eradication led to the reduction of intact (JHRPi = 53 +/- 26 ng/h.cm) but not of degraded (JD = 844 +/- 213 ng/h.cm) HRP fluxes. After eradication, degraded HRP fluxes returned to normal in mice without inflammation (JD = 558 +/- 36 ng/h.cm2) but not in those with persistent inflammation (JD = 987 +/- 310 ng/h.cm2). CONCLUSIONS: The results suggest that during H. felis infection, bacterial colonization and inflammation lead to an increased gastric permeability along the direct and degradative pathways, respectively. Such an increased antigenic load could contribute to the perpetuation of gastric inflammation after bacterial eradication, and possibly to food protein sensitization.

Whole-body protein metabolism assessed by leucine and glutamine kinetics in adult patients with active celiac disease.

To assess the effect of increased renewal of intestinal epithelial cells on leucine and glutamine (Gln) turnover, 4-hour intravenous infusions of L-[1-(13)C]leucine and L-[2-(15)N]Gln were administered to five adult patients with active celiac disease in the postabsorptive state. There was a 35% increase in leucine flux (micromoles per kilogram per hour) in patients (117 +/- 17) compared with healthy controls (96 +/- 11, P < .03). Gln flux was increased by 13% in patients (377 +/- 35) versus controls (335 +/- 16, P < .04). These results suggest that active celiac disease, characterized by villous atrophy and crypt cell hyperplasia, is associated with a dramatic increase in whole-body protein breakdown as assessed by 13C-leucine, which may contribute per se to the protein malnutrition status of the patients. The increase in Gln utilization as assessed by L-[2-(15)N]Gln was moderate, but may have been offset due to the villose atrophy and ensuing reduced intestinal epithelial cell mass. The results are consistent with the concept that increased renewal of intestinal epithelial cells represents a sizable fraction of whole-body protein turnover and that Gln is an important fuel for epithelial intestinal cells in vivo.

Sensitization to cow's milk proteins during refeeding of guinea pigs recovering from polydeficient malnutrition.

We have previously shown that milk sensitization aggravates intestinal dysfunction in the malnourished guinea pigs, suggesting that it may also impair the recovery from malnutrition. To test this hypothesis, the growing guinea pigs were malnourished by feeding only maize for 7 d and then were refed for 21 d with a balanced diet containing either intact or hydrolyzed cow's milk proteins. The control animals received the hydrolyzed milk protein diet for 28 d. After an initial period of total inhibition of growth owing to maize, guinea pigs gained weight regularly, with both balanced diets, and there was no evidence of mucosal damage at the end of the refeeding period. However, refeeding with intact milk proteins induced milk sensitization, which was demonstrated on the systemic level by the presence of anti-beta-lactoglobulin IgG1 antibodies, and on the local level by the intestinal anaphylaxis measured by the increase in short circuit current induced by beta-lactoglobulin (16.4 +/- 2.6 microA/cm2) in jejunal segments mounted in Ussing chambers. Such an immune sensitization was associated with impaired intestinal permeability, as both the ionic conductance (21.0 +/- 1.6 versus 14.6 +/- 0.7 mS/cm2) and the transepithelial fluxes of horseradish peroxidase (537 +/- 203 versus 152 +/- 28 ng/h x cm2) were significantly increased in guinea pigs refed with the intact milk proteins compared with controls. In contrast, there was no difference in intestinal permeability between controls and guinea pigs refed with the hydrolyzed milk protein diet. These data show that sensitization to cow's milk proteins can develop in guinea pigs recovering from severe malnutrition and may impair full intestinal repair.

Helicobacter pylori alters exogenous antigen absorption and processing in a digestive tract epithelial cell line model.

To study the influence of Helicobacter pylori on epithelial barrier function, bacteria, bacterial sonicates, or broth culture supernatants were incubated for 24 h with HT29-19A intestinal cells grown as monolayers. Subsequently, the monolayers were mounted in Ussing chambers, and electrical resistance (R), fluxes of 22Na (JNa) and 14C-mannitol (JMan) (markers of the paracellular pathway), and fluxes of horseradish peroxidase (HRP) in total (J3H-HRP), intact (JHRPi), and degraded forms were measured. H. pylori did not induce any modification of the paracellular pathway (R = 148 +/- 10 versus 174 +/- 16 Omega. cm2; JNa = 4.16 +/- 0.44 versus 3.51 +/- 0.41 microEq/h. cm2; JMan = 0.081 +/- 0.01 versus 0.058 +/- 0.009 micromol/h. cm2), nor did it modify J3H-HRP (2,201 +/- 255 versus 2, 110 +/- 210 ng/h. cm2 for H. pylori-infected and control cells, respectively). However, in the presence of H. pylori, we observed a significant increase in JHRPi (520 +/- 146 versus 171 +/- 88 ng/h. cm2). This effect was not dependent of the cag status of the strain and was not reproduced by the sonicates or the culture supernatants. It was related to the presence of urease, since a urease-negative mutant of H. pylori did not induce this effect. Ammonia and bafilomycin A1, two agents known to increase the endolysosomal pH, reproduced the increase in JHRPi. In conclusion, H. pylori does not affect directly the integrity of intercellular junctions of epithelial cells in vitro, but it increases the passage of intact HRP, probably by inhibition of the intralysosomal degradation due to the release of ammonia. The increased transport of intact macromolecules may contribute to the induction and maintenance of gastric inflammation by H. pylori.

Protein transport and processing by human HT29-19A intestinal cells: effect of interferon gamma.

BACKGROUND: The nature of the breakdown products produced in enterocytes during epithelial transport of intact proteins may be critical in determining the functional consequences of protein absorption. AIM: (a) To measure the transepithelial transport of horseradish peroxidase (HRP) and to identify the nature of HRP breakdown products released on the basal side of enterocytes and (b) to assess the role of interferon gamma (IFN gamma) on HRP transport and processing. METHODS: HT29-19A intestinal cells were used to assess transepithelial transport of HRP in Ussing chambers, and the nature of breakdown products in the basal compartment was analysed by high performance liquid chromatography (HPLC). RESULTS: (1) In control conditions, [3H]HRP equivalent fluxes (3135 (219) ng/h per cm2; mean (SEM) comprised 50% amino acids, 40% peptides, and 10% intact HRP. Steric exclusion HPLC of the breakdown products indicated a wide range of molecular masses including a major peptide of about 1150 Da. Lysosomal aspartyl and thiol proteases were expressed but no HLA-DR surface expression was noted, (2) At 48 to 72 hours after IFN gamma stimulation, [3H]HRP equivalent fluxes increased significantly (7392 (1433) ng/h per cm2) without modification of the relative proportions of amino acids, peptides, and intact HRP, and without modification of the distribution of breakdown products in HPLC. Lysosomal protease activities were not modified by IFN gamma but HLA-DR expression was increased. CONCLUSION: Intestinal cells are able to process HRP into peptides potentially capable of stimulating the immune system. IFN gamma stimulates the transport and processing of HRP thus increasing the antigenic load in the intestinal mucosa.

[Definition and evaluation of therapeutic food for severely malnourished children in situations of humanitarian emergencies]. / Définition et évaluation d'un aliment thérapeutique pour les enfants sévèrement malnutris, en situation d'urgence humanitaire.

Nowadays, median case fatality rate of severely malnourished children treated in hospitals is 23.5%, a rate which has not changed for the last 50 years. This is probably related to the use of inappropriate or even unsafe treatment protocols. This work aimed at reducing case fatality rates of severe malnutrition by developing a treatment protocol and assessing its effectiveness during humanitarian crises. A therapeutic food was designed from pathophysiologic studies and its use adapted to therapeutic feeding centres. This food (F100) contains 100 Kcal/100 ml, with 10% of its energy derived from proteins; it has a low sodium and iron content but is fortified with vitamins and minerals. It can be prepared either at the treatment centre or at an industrial level. Industrial production, which started in 1993 reached 1,500 MT in 1997. In refugee camps, F100 was used according to a strict protocol adapted to local conditions. Intakes started at 100 Kcal/kg/day and reached 200 kcal/kg/day once appetite was restored. A model to assess the risk of death according to weight, height and oedema was developed. First results show that mortality was often below 5%. Hence, it is possible to standardise and evaluate a nutritional treatment in such unfavourable conditions as a refugee camp. Standardised use of F100 can markedly reduce mortality of severely malnourished children.