A novel infant milk formula concept: Mimicking the human milk fat globule structure.

Human milk (HM) provides all nutrients to support an optimal growth and development of the neonate. The composition and structure of HM lipids, the most important energy provider, have an impact on the digestion, uptake and metabolism of lipids. In HM, the lipids are present in the form of dispersed fat globules: large fat droplets enveloped by a phospholipid membrane. Currently, infant milk formula (Control IMF) contains small fat droplets primarily coated by proteins. Recently, a novel IMF concept (Concept IMF) was developed with a different lipid architecture, Nuturis(®), comprising large fat droplets with a phospholipid coating. Confocal laser scanning microscopy (CLSM), with appropriate fluorescent probes, and transmission electron microscopy were used to determine and compare the interfacial composition and structure of HM fat globules, Concept IMF fat droplets and Control IMF fat droplets. The presence of a trilayer-structured HM fat globule membrane, composed of phospholipids, proteins, glycoproteins and cholesterol, was confirmed; in addition exosome-like vesicles are observed within cytoplasmic crescents. The Control IMF fat droplets had a thick protein-only interface. The Concept IMF fat droplets showed a very thin interface composed of a mixture of phospholipids, proteins and cholesterol. Furthermore, the Concept IMF contained fragments of milk fat globule membrane, which has been suggested to have potential biological functions in infants. By mimicking more closely the structure and composition of HM fat globules, this novel IMF concept with Nuturis(®) may have metabolic and digestive properties that are more similar to HM compared to Control IMF.

Enzymatic treatment of whey proteins in cow's milk results in differential inhibition of IgE-mediated mast cell activation compared to T-cell activation.

BACKGROUND: Cow's milk (CM) hydrolysates are frequently used as milk substitutes for children with CM allergy. In hydrolysates, allergenic epitopes within CM proteins are diminished by enzymatic treatment. The aim of this study was to examine the allergenic and immunogenic properties of whey proteins during hydrolysis. METHODS: During hydrolysis, samples were obtained at 0, 10, 15, 30, 45, 60, 75 and 90 min. Degradation was checked by HPLC and SDS-PAGE. Allergenic potential was analyzed by IgE crosslinking capacity of human Fcε receptor type 1-transduced rat basophilic leukemia cells sensitized with serum of CM-allergic patients. Whey-sensitized C3H/HeOuJ mice were ear challenged intracutaneously with the hydrolysates. Immunogenicity was tested using whey-specific human T-cell clones and T-cell lines at the level of proliferation and release of IL-4, IL-10, IL-13 and IFN-γ. RESULTS: After 15 min of hydrolysis, the majority of the proteins were degraded. Hydrolysis for 15 min resulted in 92% inhibition of mast cell degranulation and in 82% reduction of ear swelling in the mouse model. In contrast, T-cell-stimulatory capacity was less affected by hydrolysis: reduction of human T-cell proliferation was only 9%. This was further reduced to 57 and 74% after 30 and 45 min of hydrolysis, respectively. Cytokine production followed the pattern of T-cell proliferation. CONCLUSION: Via differential analysis of allergenic versus immunogenic properties of the time kinetics of hydrolysis of whey proteins, we have demonstrated specific hydrolysis conditions with reduced IgE-crosslinking responses but retained T-cell activating properties. This approach might be useful in better defining CM hydrolysates.

Acute allergic skin response as a new tool to evaluate the allergenicity of whey hydrolysates in a mouse model of orally induced cow's milk allergy.

Hypoallergenic milk formulae are used for cow's milk allergic infants and may be a good option for infants at risk. Clinical studies have shown that the protein source or the hydrolysis methodology used may influence the effectiveness in infants stressing the importance of adequate pre-clinical testing of hypoallergenic formulae in an in vivo model of orally induced cow's milk allergy. This study was undertaken to introduce a new read-out system to measure the residual allergenicity of whey hydrolysates on both the sensitization and challenge phase of orally induced cow's milk allergy in mice. Mice were sensitized orally to whey or a partial whey hydrolysate (pWH) to measure the residual sensitizing capacity. To predict the residual allergenicity of hydrolysates, whey allergic mice were challenged in the ear with pWH, extensive whey hydrolysate or an amino acid-based formula. An acute allergic skin response (ear swelling at 1 h), whey-specific serum antibodies, and local MCP-1 concentrations were measured. In contrast to whey, oral sensitization with pWH did not result in the induction of whey-specific antibodies, although a minor residual skin response to whey was observed after challenge. Skin exposure to whey hydrolysates showed a hydrolysation dependent reduction of the acute allergic skin response in whey allergic mice. In contrast to whey, skin exposure to pWH did not enhance tissue MCP-1 levels. The acute allergic skin response in mice orally sensitized to cow's milk proteins reveals a new pre-clinical tool which might provide information about the residual sensitizing capacity of hydrolysates supporting the discussion on the use of hypoallergenic formulae in high risk children. This mouse model might be a relevant model for the screening of new hypoallergenic formulae aimed to prevent or treat cow's milk allergy.