Giulio De Marco

Probiotics for treatment of acute diarrhoea in children: randomised clinical trial of five different preparations

Objective To compare the efficacy of five probiotic preparations recommended to parents in the treatment of acute diarrhoea in children. Design Randomised controlled clinical trial in collaboration with family paediatricians over 12 months. Setting Primary care. Participants Children aged 3-36 months visiting a family paediatrician for acute diarrhoea. Intervention Childrens parents were randomly assigned to receive written instructions to purchase a specific probiotic product: oral rehydration solution (control group); Lactobacillus rhamnosus strain GG; Saccharomyces boulardii; Bacillus clausii; mix of L delbrueckii var bulgaricus, Streptococcus thermophilus, L acidophilus, and Bifidobacterium bifidum; or Enterococcus faecium SF68. Main outcome measures Primary outcomes were duration of diarrhoea and daily number and consistency of stools. Secondary outcomes were duration of vomiting and fever and rate of admission to hospital. Safety and tolerance were also recorded. Results 571 children were allocated to intervention. Median duration of diarrhoea was significantly shorter (P<0.001) in children who received L rhamnosus strain GG (78.5 hours) and the mix of four bacterial strains (70.0 hours) than in children who received oral rehydration solution alone (115.0 hours). One day after the first probiotic administration, the daily number of stools was significantly lower (P<0.001) in children who received L rhamnosus strain GG and in those who received the probiotic mix than in the other groups. The remaining preparations did not affect primary outcomes. Secondary outcomes were similar in all groups. Conclusions Not all commercially available probiotic preparations are effective in children with acute diarrhoea. Paediatricians should choose bacterial preparations based on effectiveness data. Trial registration number Current Controlled Trials ISRCTN56067537.

Lactoferrin Induces Concentration-Dependent Functional Modulation of Intestinal Proliferation and Differentiation

Human milk stimulates intestinal development through the effects of various moieties. Lactoferrin (LF) is a glycoprotein of human milk whose concentration is highest in colostrum decreasing in mature milk. LF promotes enterocyte growth in intestinal cell lines. We tested the hypothesis that LF induces a distinct effect on enterocyte proliferation and differentiation, depending on its concentration. We examined the dose-related effects by human-native LF (N-LF) in Caco-2 (human colon adenocarcinoma) cells. At high concentrations, N-LF stimulated cell proliferation in immature Caco-2 cells, as judged by 3H-thymidine incorporation. In contrast, sucrase and lactase activities were increased at low but not high LF concentrations and their mRNA were also increased, indicating a transcriptional effect. Because iron binds specific LF sites, we compared the potency of N-LF and iron-saturated LF (I-LF) and found the native form more potent. Finally, we tested the effects by bovine LF (bLF) in the same system and found the latter more potent than the human isoform in inducing cell growth and lactase expression. These results suggest that LF directly induces enterocyte growth and proliferation, depending on its concentration, thereby regulating the earlyx postnatal intestinal development. bLF could be added to infant formula as a growth factor in selected intestinal diseases.

Zinc Inhibits Cholera Toxin-Induced, but Not Escherichia coli Heat-Stable Enterotoxin-Induced, Ion Secretion in Human Enterocytes

BACKGROUND Because zinc deficiency in malnourished children is associated with severe diarrhea, use of zinc supplementation has been proposed as an adjunct to oral rehydration. However, the effects of zinc on enterocyte ion transport are largely unknown. The objective of the present study was to investigate the effects of zinc on transepithelial ion transport under basal conditions and under conditions of enterotoxin-induced ion secretion. METHODS Ion transport was investigated by monitoring electrical parameters in human intestinal Caco-2 cells that were mounted in Ussing chambers and exposed to increasing concentrations of zinc, both in the absence and presence of either cholera toxin (CT) or Escherichia coli heat-stable enterotoxin (ST). Intracellular cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) concentrations were also determined. RESULTS The addition of zinc to the luminal or basolateral side of enterocytes induced a chloride-dependent, dose-related decrease in short-circuit current, indicating ion absorption. It also resulted in a substantial reduction in CT-induced ion secretion and in cAMP concentration. E. coli ST-induced ion secretion and cGMP concentration were not affected. Ion absorption peaked at 35 mu mol/L zinc, whereas excess zinc load induced active ion secretion. CONCLUSIONS By causing a decrease in cAMP concentration, zinc directly promotes ion absorption and substantially reduces CT-induced, but not E. coli ST-induced, ion secretion.

Natural history of intestinal failure, investigated through a national network-based approach

Objectives Intestinal failure (IF) is a condition whose treatment requires advanced knowledge and techniques and a multidisciplinary approach. Intestinal failure is the endpoint of many intestinal diseases and may result in full recovery, in life-long parenteral nutrition, or in the death of the child. The aim of this study was to evaluate the natural history of IF in children using a national network of resources. Methods Italian centers of pediatric gastroenterology merged in a national network, developing a collaborative management approach for children with IF. A consensus definition of IF was achieved. A database was set up to investigate the cause, epidemiologic factors, and natural history of IF. Results One hundred nine children were enrolled in 5 years. The cause of IF was: short bowel syndrome (n = 48), disorders of motility (n = 16), structural enterocyte defects (n = 14), multiple food intolerance (n = 10), autoimmune enteropathy (n = 7), and others or unknown (n = 14). The eventual outcome was closely related to the primary cause, ranging from full and permanent intestinal sufficiency in children with multiple food intolerance to high death rate or total dependance upon parenteral nutrition in those with structural enterocyte defects. Intermediate outcomes were observed for the other causes. Four children received intestinal transplantation. Conclusions The network approach for IF provides an effective model to optimize resources and to investigate prospectively the natural history of IF. Based on the work on this series, a European network for IF could be an effective model for fulfilling the diagnostic and management needs, including intestinal transplantation.

Management of gastrointestinal disorders in children with HIV infection.

A double scenario characterizes the epidemiology of HIV infection in children. In countries where highly active antiretroviral therapy (HAART) is available, the pattern of HIV infection is evolving into that of a chronic disease, for which control strictly depends on patients’ adherence to treatment. In developing countries with no or limited access to HAART, AIDS is rapidly expanding and is loaded with a high fatality ratio, due to the combined effects of malnutrition and opportunistic infections.The digestive tract is a target of the disease in both settings. Opportunistic infections play a major role in children with severe immune impairment, with Cryptosporidium parvum being the leading agent of severe diarrhea. Several therapeutic approaches are effective in reducing fecal output, but the eradication of the parasite is rarely obtained. Other opportunistic infections may induce severe and protracted diarrhea, including atypical mycobacteria and cytomegalovirus. Diagnosis of diarrhea should be individually tailored based on presenting symptoms and risk factors. A stepwise approach is effective in limiting patient discomfort and minimizing the costs of investigations, starting with microbiologic investigation and proceeding with endoscopy and histology. Aggressive treatment of infectious diarrhea is required in severely immunocompromised children. However, antiretroviral therapy prevents the development of severe cryptosporidiosis.The liver and pancreas are also target organs in HIV infection, although functional failure is rare. The digestive-absorptive functions are impaired, with steatorrhea, nutrient malabsorption, and increased permeability occurring in 20–70% of children. Intestinal dysfunction contributes to growth failure and further immune derangement, leading to wasting, the terminal stage of AIDS. Nutritional management is crucial in HIV-infected children and is based on aggressive nutritional rehabilitation through enteral or parenteral routes and micronutrient supplementation.HIV may play a direct enteropathogenic role and is implicated in both diarrhea and intestinal dysfunction. This explains the efficacy of antiretroviral therapy in inducing remission of diarrhea and restoring intestinal function.Gastrointestinal side effects of antiretroviral drugs are increasingly observed; they are often mild and transient. Severe reactions are rare but require the withdrawal of drugs.In conclusion, severe enteric infections and intestinal dysfunction characterize the intestinal involvement of HIV infection. This is more common in, but not limited to, children who do not receive effective antiretroviral therapy. Diagnostic approaches include microbiologic and morphologic examinations and assessment of digestive processes, but immunologic and virologic data should be also carefully considered. Treatment is based upon specific anti-infectious drugs, antiretroviral therapy, and nutritional rehabilitation.

Efficacy of a New Hypotonic Oral Rehydration Solution Containing Zinc and Prebiotics in the Treatment of Childhood Acute Diarrhea: A Randomized Controlled Trial

OBJECTIVE To evaluate the efficacy of a hypotonic oral rehydration solution (ORS) containing zinc and prebiotics for treatment of acute diarrhea in children. STUDY DESIGN We conducted a single-blind, prospective, controlled trial including children (age range, 3-36 months) with acute diarrhea randomly assigned to standard hypotonic ORS (group 1) or to new hypotonic ORS containing zinc and prebiotics (group 2). The main outcome was the rate of resolution of diarrhea at 72 hours. RESULTS A total of 60 children in group 1 (34 male; mean age, 18.58 months; 95% CI, 15.5-21.6) and 59 in group 2 (36 male; mean age, 19.26 months; 95% CI, 15.9-22.6) completed the study protocol. The rate of diarrhea resolution at 72 hours was higher in group 2 (50% versus 72.9%, P = .010). Total ORS intake in the first 24 hours was higher in group 2 (50 mL/kg; 95% CI, 41-59 versus 22 mL/kg; 95% CI, 17-29; P < .001). The mean number of missed working days by the parents of children in group 2 was lower (0.39; 95% CI, 0.08-0.70 versus 1.45; 95% CI 1.02-1.88; P < .001). Fewer patients in group 2 needed adjunctive drugs for the treatment of diarrhea 6/59 versus 19/60, P = .004. No adverse events were observed in either of the two groups. CONCLUSION The addition of zinc and prebiotics to ORS limits diarrhea duration in children.

Antiemetics for children with gastroenteritis : Off-label but still on in clinical practice

ABSTRACT Antiemetics are not included for treatment of vomiting associated with acute gastroenteritis (AGE) in children by standard guidelines. We performed a survey to determine antiemetic prescribing rates by Italian pediatricians. A structured questionnaire was distributed at a pediatric national conference. The majority of responders reported prescribing antiemetics for pediatric gastroenteritis. Although there is insufficient evidence to justify their use, the use of antiemetics is widely present among pediatricians.

Inhibitory effect of HIV-1 Tat protein on the sodium-D-glucose symporter of human intestinal epithelial cells.

Objective:The pathophysiology of HIV-1-related intestinal dysfunction is largely unknown. We previously found that the transactivator factor peptide (Tat) produced by HIV-1 induces ion secretion and inhibits cell proliferation in human enterocytes. Because sugar malabsorption is a frequent feature in AIDS patients, we evaluated whether Tat inhibits intestinal glucose absorption. Design and methods:We measured Na+-D-glucose symporter (SGLT-1) activity and determined its phenotypic expression in Caco-2 cells, in the presence and absence of Tat, in uptake experiments using a non-metabolized radiolabelled glucose analogue, and by western blot analysis, respectively. α-Tubulin staining was used to study the effects exerted by Tat on cell structure. Results:Tat dose dependently inhibited glucose uptake by human enterocytes. This effect was prevented by anti-Tat polyclonal antibodies and by L-type Ca2+ channels agonist Bay K8644. Western blot analysis of cellular lysates and brush-border membrane preparations showed that Tat induced SGLT-1 missorting. Tat also caused a dramatic decrease in α-tubulin staining, which indicates dysruption of the cytoskeleton organization. Conclusions:Tat acutely impairs intestinal glucose absorption through SGLT-1 missorting. This result indicates that Tat is directly involved in AIDS-associated intestinal dysfunction.

Nitric Oxide Produced by the Enterocyte Is Involved in the Cellular Regulation of Ion Transport

The role of nitric oxide (NO) in the intestinal basal ion transport and under conditions of enterotoxin-induced ion secretion is controversial. Namely it is not clear whether NO enhances or counteracts intestinal ion secretion and whether the effects on transport result from a direct interaction with the enterocyte. The cell origin of NO is also unclear. We have tested the hypothesis that NO produced by the enterocyte directly regulates ion transport processes either in basal condition or in response to cholera toxin-induced secretion. Electrical variables reflecting transepithelial ion transport were measured in Caco-2 cell monolayers mounted in Ussing chambers exposed to the NO synthase inhibitor Nω-nitro-L-arginine methyl ester, in the presence or absence of cholera toxin. cAMP concentrations were also measured. NO release was determined by nitrite-nitrate concentration. NO synthase activities were assayed by Western blot analysis. Nω-nitro-L-arginine methyl ester had a secretory effect, as judged by increased basal short-circuit current and cAMP concentration. It also increased cholera toxin-induced electrical response and cAMP production. Either cholera toxin or the cAMP analog 8-bromo-cAMP induced a rapidly progressive and Ca2+-dependent increase in NO concentration, suggesting a homeostatic up-regulation of the constitutive form of NO synthase. Western blot analysis showed an increase in constitutive NO synthase enzyme isoform. These results indicate that the enterocyte regulates its own ion transport processes, either in basal condition or in the presence of active secretion, through the activation of a constitutive NO synthase-NO pathway, functioning as a braking force of cAMP-induced ion secretion.

Rotavirus induces a biphasic enterotoxic and cytotoxic response in human-derived intestinal enterocytes, which is inhibited by human immunoglobulins.

The mechanisms of diarrhea due to rotavirus infection in humans are not fully understood; no specific therapy is available, but orally administered human serum immunoglobulins are effective in blocking stool output. We aimed to investigate the effect of rotavirus on ion transport and the role of NSP4 in human-derived enterocytes, and to test the efficacy of human serum immunoglobulin in a model of rotavirus infection. Soon after infection, rotavirus induces active chloride secretion in enterocytes. This effect is evident before viral replication leads to cell damage and correlates with NSP4 production. Inhibition of NSP4 prevents the early secretory phase but not cell damage. Incubation with human serum immunoglobulin blocks both ion secretion and cell damage. Rotavirus exerts an early NSP4-dependent ion secretion and subsequent tissue damage. The combined enterotoxic and cytotoxic effects may be responsible for the increased severity of diarrhea due to rotavirus infection, and both are counteracted by human serum immunoglobulin.