S. Ruotolo

Diagnostic accuracy of the atopy patch test in children with food allergy‐related gastrointestinal symptoms

Background:  Little is known about the diagnostic accuracy of atopy patch tests (APT) in the clinical practice of pediatric gastroenterology. Moreover, APTs containing purified food extracts have recently become available, but their diagnostic accuracy is largely undefined.

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.

The diagnosis of food allergy in children.

Purpose of review To give an update about the optimal diagnostic work-up for children with suspected food allergy. Recent findings Food allergy has become a very severe health problem not only for many children and parents, but also for the entire medical and paramedical community. The financial and social costs related to these conditions are increasing, but, contemporarily, basic and clinical research are deeply involved in the search of possible solutions to facilitate the management of these patients. Summary Food allergy is defined as an abnormal immunological reaction to food proteins, which causes an adverse clinical reaction. Over 90% of food allergies in childhood are caused by eight foods: cows milk, hens egg, soy, peanuts, tree nuts, wheat, fish and shellfish. The evaluation of a child with suspected food allergy includes detailed medical history, physical examination, screening tests and response to elimination diet and to oral food challenge. None of the screening tests, alone or in combination, can definitely diagnose or exclude it. The main principle of food allergy management is avoidance of the offending antigen. An incorrect diagnosis is likely to result in unnecessary dietary restrictions, which, if prolonged, may adversely affect the childs nutritional status and growth.

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.

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.

The Effects of Dietary Counseling on Children with Food Allergy: A Prospective, Multicenter Intervention Study

Although dietary counseling is generally recommended in children with food allergy (FA), its effect on the nutritional status of these patients has not yet been evaluated. Our nonrandomized multicenter prospective intervention study was undertaken to investigate the effects of dietary counseling on children with FA. Anthropometric data, dietary intakes, and laboratory biomarkers of nutritional status were evaluated in children with FA (aged 6 to 36 months) before and after dietary counseling, by multidisciplinary teams composed of pediatricians, dietitians, and nurses. Ninety-one children with FA (49 boys and 42 girls; mean age 18.9 months, 95% CI 16.5 to 21.3) were evaluated; 66 children without FA (41 boys and 25 girls; mean age 20.3 months, 95% CI 17.7 to 22.8) served as controls providing baseline values only. At enrollment, energy and protein intakes were lower in children with FA (91 kcal/kg/day, interquartile range [IQR]=15.1, minimum=55.2, maximum=130.6; and 2.2 g/kg/day, IQR=0.5, minimum=1.5, maximum=2.7, respectively) than in children without FA (96 kcal/kg/day, IQR=6.1, minimum=83.6, maximum=118.0; and 4.6 g/kg/day, IQR=1.2, minimum=2.0, maximum=6.1, respectively; P<0.001). A weight to length ratio <2 standard deviations was more frequent in children with FA than in children without FA (21% vs 3%; P<0.001). At 6 months following dietary counseling, the total energy intake of children with FA was similar to the baseline values of control children. Dietary counseling also resulted in a significant improvement of their anthropometric and laboratory biomarkers of nutritional status. The results of our study support the crucial role of dietary counseling in the clinical management of children with FA.

Zinc inhibits calcium-mediated and nitric oxide-mediated ion secretion in human enterocytes

Zn(2+) is effective in the treatment of acute diarrhea, but its mechanisms are not completely understood. We previously demonstrated that Zn(2+) inhibits the secretory effect of cyclic adenosine monophosphate but not of cyclic guanosine monophosphate in human enterocytes. The aim of the present study was to investigate whether Zn(2+) inhibits intestinal ion secretion mediated by the Ca(2+) or nitric oxide pathways. To investigate ion transport we evaluated the effect of Zn(2+) (35 microM) on electrical parameters of human intestinal epithelial cell monolayers (Caco2 cells) mounted in Ussing chambers and exposed to ligands that selectively increased intracellular Ca(2+) (carbachol 10(-6)M) or nitric oxide (interferon-gamma 300 UI/ml) concentrations. We also measured intracellular Ca(2+) and nitric oxide concentrations. Zn(2+) significantly reduced ion secretion elicited by carbachol (-87%) or by interferon-gamma (-100%), and inhibited the increase of intracellular Ca(2+) and nitric oxide concentrations. These data indicate that Zn(2+) inhibits ion secretion elicited by Ca(2+) and nitric oxide by directly interacting with the enterocyte. They also suggest that Zn(2+) interferes with three of the four main intracellular pathways of intestinal ion secretion that are involved in acute diarrhea.

Zinc fights diarrhoea in HIV-1-infected children: in-vitro evidence to link clinical data and pathophysiological mechanism.

Diarrhoea-related morbidity is reduced by zinc supplementation in HIV-1-infected children. The mechanisms of this effect are largely undefined. We provide evidence for role for Tat (transactivating peptide produced by HIV-1) in the pathogenesis of diarrhoea in AIDS patients. In this study we showed that zinc, preventing Tat-induced fluid secretion, directly limits a specific mechanism of HIV-1-related diarrhoea. Our data support a ‘zinc approach’ in adjunct to specific antiretroviral therapy in HIV-1-infected children.

Adherence to recommendations for primary prevention of atopic disease in neonatology clinical practice.

Passariello A, Terrin G, Baldassarre ME, Bisceglia M, Ruotolo S, Berni Canani R. Adherence to recommendations for primary prevention of atopic disease in neonatology clinical practice.
Pediatr Allergy Immunol 2010: 21: 889–891.
© 2010 John Wiley & Sons A/S

Peripheral Blood Immune Response Elicited by Beta-Lactoglobulin in Childhood Cow's Milk Allergy

Several studies analyzing the immune responses in patients with cows milk allergy (CMA) have used T-cell lines or T-cell clones that require prolonged in vitro cell culturing and may result in a switched cell phenotype and function. We investigated immune responses to beta-lactoglobulin (b-LG) in peripheral blood mononuclear cells after a short in vitro antigen stimulation in children with acute CMA (both IgE-mediated and non-IgE-mediated forms) and in those who outgrew an IgE-mediated CMA. Healthy controls were also investigated. Peripheral blood mononuclear cells were assayed for IL-13, IFN-γ, IL-4, and IL-10. Although b-LG induced a cytokine production and/or cell proliferation almost in all children, included healthy controls, differences were observed among the four groups. Children with IgE-mediated CMA had a marked Th2-response, with high IL-13 production and proliferation, but low IFN-γ; by contrast, children with non-IgE-mediated CMA produced no, or very low, IL-13 and cell proliferation. Children, who outgrew CMA, showed a shift to a Th1-response, with reduced IL-13 and increased IFN-γ. IL-10-responses were high in all groups, with the highest level in healthy children; by contrast, IL-4 was undetectable in all children. This study highlights the use of shortly stimulated peripheral blood cells to investigate the food-induced immune responses.