Probiotics, prebiotics, and allergy in children: what's new in the last year?

Nasal microbiome in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is defined as an inflammatory disorder of the paranasal sinuses and of the nasal mucosa that lasts 12 weeks or longer. In CRS microbes contribute to the disease pathogenesis. Clinical microbiology is focused on finding single pathogens that causes the disease and the main goal is the use of antibiotics to kill bacteria. Efforts to achieve a better understanding of CRS include the study of the sinus microbiome, and to evaluate the ability of probiotics to augment homeostasis and modulate the immune response of the host mucosa. This review provides an update on the role of the microbiome in CRS. The study was conducted using two databases: PubMed and Science Direct. We searched for articles in English that matched the review topic. We first used the abstracts of articles to assess whether they met the inclusion criteria. We also reviewed the references of the selected articles and read those with titles that might be of interest. Several studies have shown that endogenous microbiome dysbiosis can impact mucosa health and disease severity. Some bacterial species presenting protective or pathogenic effect. Antimicrobial agents can create a similar disruption and impact the nasal microbiome balance. On the other hand, probiotics offers a promising avenue for developing systemic and topical therapies geared towards strategic manipulation of the biological host load, thereby augmenting immune homeostasis. A better comprehension of sinus-nasal microbiome in healthy and in CRS patients and the link with different CRS phenotype can help in developing new prognostics, diagnostics, and therapeutics strategies. Going forward, the use of probiotics can restore the native sinus ecology with significant therapeutic and preventive implications.

Use of a Probiotic to Enhance Iron Absorption in a Randomized Trial of Pediatric Patients Presenting with Iron Deficiency

OBJECTIVE

To evaluate the efficacy of low dose ferrous sulfate for the treatment of iron deficiency and if the probiotic Lactobacillus plantarum 299v (LP299v) enhances treatment.

STUDY DESIGN

This randomized, double-blinded, controlled trial of the treatment of iron deficiency in children compared the use of low-dose ferrous sulfate (1-3 mg/kg/day), with or without probiotic (LP299v).

RESULTS

Serum ferritin level increased in all children from a baseline of 23.7 ng/mL to 45.4 ng/mL after 6-8 weeks of treatment. There was no significant difference in the increase in serum ferritin in children taking the probiotic LP299v compared with controls (23.2 vs 20.0 ng/mL, respectively). Additionally, an increase in ferritin level was not significantly associated with probiotic use when controlling for other factors, including child weight and dosing. Overall, the treatments were well-tolerated, with mild side effects.

CONCLUSIONS

Treatment with low-dose ferrous sulfate is well-tolerated and effective in correcting iron deficiency in children. However, the probiotic LP299v did not enhance treatment. Further attention should examine the dose-response effect in children, including an alternate day dosing schedule.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01617044.

Acute allergic reactions in Vietnamese children after drinking a new milk product

In early October 2009, pediatricians in hospitals in Ho Chi Minh City (HCMC) reported an unusual increase in the number of children presenting with an acute onset of itchy rash and some with breathing difficulties shortly after drinking milk products. The pediatricians considered the illness to be an allergic reaction to milk. The objective of our investigation was to identify the cause of this acute illness. Following early case reports, all hospitals in HCMC were requested to report cases of this illness. Parents were advised to take children with symptoms to a hospital immediately. A case-series was conducted to generate hypotheses on the possible causes of the illness and was followed by a case-control study to test the hypothesis. Parents of all cases and controls were interviewed face-to-face. The association between food items and the allergy was tested using conditional logistics regression. From 9 to 28 October 2009, 19 cases fulfilled the case definition, and 16 of the 17 cases included in the study had consumed milk supplemented with galacto-oligosaccharides (GOS) shortly before the onset of illness. Fifty age-matched, neighborhood controls were enrolled into the case control study. Of the 30 food items consumed by study participants in the preceding 24 h, only the odds ratio (OR) of milk supplemented with GOS was statistically significant: OR=34.0 (95% CI=3.9, 294.8). Laboratory tests of this milk product did not reveal any unusual properties, chemicals, or other toxic substances. This is the first report of an acute allergic reaction to fresh milk supplemented with GOS. However, the specific allergen in this product was not identified. Further cases were not reported once this product was withdrawn from sale. Vietnam's food safety authorities should expand laboratory capacity to detect allergens in food products.

Exposure to a galactooligosaccharides/inulin prebiotic mix at different developmental time points differentially modulates immune responses in mice

Prebiotics constitute emerging tools to alleviate immune pathologies. This study aimed to evaluate the effect of prebiotic exposure during perinatal and postweaning periods on immune and gut regulations. Mice were fed either a galactooligosaccharides/inulin prebiotic mix-enriched diet or a control diet during the perinatal and/or postweaning periods. Biomarkers related to gut barrier function (SCFA, heat shock proteins, zonula occludens protein-1, and mucin-2) and immune mechanisms (IgA, IgE, IgG1, IgG2a, IL-10, TGF-β, IL-4, IL-17A, and IFN-γ) were analyzed. The milk of dams fed the prebiotic diet was more concentrated in both IgA and TGF-β when prebiotics were introduced during both the perinatal and postweaning periods; IL-10, IgA, and IgG2a were increased in pups; and expression of intestinal markers was more pronounced. Postweaning exposure to prebiotics alone induced higher INF-γ and TGF-β levels, whereas IgA levels fell. Combined exposure periods (perinatal/postweaning) to prebiotics increased tolerance-related immunoglobulins in pups and reinforced gut barrier functions.

Food allergy and probiotics in childhood

Food allergy is a frequent problem in childhood and its prevalence is increasing. In most cases food allergy is an IgE-mediated hypersensitivity response that cause skin reactions as urticaria. Subacute or chronic disorders have generally a not IgE mediated mechanism. Milk is the most common food allergen in USA and UK followed by egg, peanut and walnuts. Sensitization to milk or egg in infancy is associated with an increased risk to develop house dust mite sensitization and asthma later in childhood. Commensal gut flora play a role in induction of oral tolerance and the importance of the intestinal microbiota in the development of food allergy is essential in early ages, when the mucosal barrier and immune system are still immature. Probiotics interact with the mucosal immune system by the same pathways as commensal bacteria. Recent study show that probiotic bacteria induced in vivo increased plasma levels IL-10 and total IgA in children with allergic predisposition. Many clinical studies reporting significant benefits by probiotics supplementation in food allergy prevention and management but not everyone agree on their effectiveness. These differences are probably related to differences in selected populations and in probiotic strains used.