Allergenicity of a hydrolyzed rice infant formula in a guinea pig model
Because sensitization to cow's milk is a common finding in children, the identification of safe alternative protein sources is important in the management of childhood allergy.
To evaluate, in an animal model, the allergenicity of a novel formula based on hydrolyzed rice proteins.
We conducted an experiment involving 130 guinea pigs, from 7 to 12 days old at the onset of the study. The animals were divided into 13 groups and were given, ad libitum, one of the following liquids to drink: (1) rice hydrolysate formula (RF), (2) a conventional cow's milk formula (CMF), or (3) water. After a 37-day sensitization period, a challenge was given, consisting of an intravenous injection of either isolated proteins or ultracentrifuged formulas (uCMF and uRF). Specific IgG antibodies to beta-lactoglobulin, casein, and whole rice protein were measured by enzyme-linked immunosorbent assay.
When animals fed CMF were challenged with beta-lactoglobulin, casein, or whole uCMF, they showed significantly more reactions than did those fed RF when challenged with the same proteins (P < 0.001). In the groups fed RF, no reaction was observed after challenge with uRF, and only 2 mild reactions occurred after challenge with rice protein. Very low levels of specific IgG antibodies to rice protein were noted in all the groups, including the RF-fed animals, and no significant differences were evident between groups.
The findings suggest that this new formula based on hydrolyzed rice proteins has a very low sensitizing capability.
Available from: Cristina Yolanda Pascual
- "In an animal model, 7-to 12-day old guinea pigs were fed a hydrolysed rice formula, a conventional cow’s milk formula or water. A challenge was given after a sensitization period (26). When challenged with the same proteins, the group receiving the cow’s milk formula showed significantly more reactions than the group receiving the hydrolysed HRPF. "
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ABSTRACT: Reche M, Pascual C, Fiandor A, Polanco I, Rivero-Urgell M, Chifre R, Johnston S, Martín-Esteban M. The effect of a partially hydrolysed formula based on rice protein in the treatment of infants with cow’s milk protein allergy. Pediatr Allergy Immunol 2010: 21: 577–585. © 2010 John Wiley & Sons A/S
Infants diagnosed with allergy to cow’s milk protein (CMP) are fed extensively hydrolysed cow’s milk formulas, modified soy formulas or even amino acid-based formulas. Hydrolysed rice protein infant formulas have become available and have been shown to be well tolerated by these infants. A prospective open, randomized clinical study to compare the clinical tolerance of a new hydrolysed rice protein formula (HRPF) with an extensively hydrolysed CMP formula (EHF) in the feeding of infants with IgE-mediated cow’s milk allergy. Ninety-two infants (46 boys and 46 girls, mean age 4.3 months, range 1.1–10.1 months) diagnosed with IgE-mediated cow’s milk allergy were enrolled in the study. Clinical tolerance to the formula products was tested. Clinical evaluation included skin prick tests with whole cow’s milk, soya and rice as well as antigens of CMP (beta-lactoglobulin, alpha-lactalbumin, casein and bovine seroalbumin), HRPF and EHF and specific IgE determinations to CMP using CAP technology. Patients were randomized to receive either an EHF based on CMP or a new HRPF. Follow-up was at 3, 6, 12, 18 and 24 months. Growth parameters were measured at each visit. One infant showed immediate allergic reaction to EHF, but no reaction was shown by any infant in the HRPF group. The number of infants who did not become tolerant to CMP during the study was not statistically different between the two groups. Measurement of IgE levels of infants allergic to CMP during the study showed no significant differences between the two formula groups. Growth parameters were in the normal range and similar between groups. In this study, the HRPF was well tolerated by infants with moderate to severe symptoms of IgE-mediated CMP allergy. Children receiving this formula showed similar growth and development of clinical tolerance to those receiving an EHF. In accordance with current guidelines, this HRPF was tolerated by more than 90% of children with CMP allergy and therefore could provide an adequate and safe alternative to CMP-hydrolysed formulas for these infants.
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ABSTRACT: Awareness of the considerable incidence of bovine protein allergy in infancy makes it necessary to eliminate cow's milk antigens from the diet in special cases. The primary objective of this review is to discuss the nutritional aspects and appropriate use of hypoallergenic formulas as a substitute for cow's milk formulas and to present new alternative feeding modalities in this field.
Related articles in PubMed (National Library of Medicine) were reviewed. This review is a synthesis of these sources along with the discussions with experts in this field and the expert opinion of the authors.
Soy protein-based and hydrolyzed milk protein formulas are the most commonly used alternative protein sources in the case of bovine protein allergy. Despite the adequacy of their nutritional values, there are still some problems to be solved regarding these formulas. In addition, a considerable percentage of the infants with bovine protein allergy may also present allergenic reactions to soy proteins as well as to hydrolyzed milk proteins. Thus, there still exists chaos in the selection of the most appropriate formula for infants sensitized to cow's milk protein. Rice protein-based formulas, probiotics, and prebiotics are expected to be new effective alternatives.
Bovine protein allergy constitutes an important place in childhood food allergies. Soy protein-based and hydrolyzed protein formulas have some disadvantages and risk of allergenic activity that is not to be underestimated. So, substitution of cow's milk protein with an alternative protein source in sensitized infants has become an art rather than a science. Rice protein, prebiotics, and probiotics appear to be valuable alternatives giving hope for the future.
Available from: Xudong Jia
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ABSTRACT: To develop a Brown Norway (BN) rat model to determine the potential allergenicity of novel proteins in genetically modified food.
The allergenicity of different proteins were compared, including ovalbumin (OVA), a potent respiratory and food allergen, bovine serum albumin (BSA), a protein that is considered to have a lesser allergenic potential, and potato acid phosphatase (PAP), a non-allergenic protein when administered to BN rats via different routes of exposure (intraperitoneally or by gavage). IgG and IgE antibody responses were determined by ELISA and PCA, respectively. An immunoassay kit was used to determine the plasma histamine level. In addition, possible systemic effect of allergens was investigated by monitoring blood pressure.
OVA provoked very vigorous protein-specific IgG and IgE responses, low grade protein-specific IgG and IgE responses were elicited by BSA, while by neither route did PAP elicit anything. In either routes of exposure, plasma histamine level in BN rats sensitized with OVA was higher than that of BSA or PAP. In addition, an oral challenge with BSA and PAP did not induce any effect on blood pressure, while a temporary drop in systolic blood pressure in few animals of each routes of exposure was found by an oral challenge with OVA.
BN rat model might be a useful and predictive animal model to study the potential allergenicity of novel food proteins.
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