Scope
Human milk exosomes provide a natural means of genetic material transfer to infants; however, the effect of gastric/pancreatic digestion milk exosomes stability and their microRNA content is ...largely unknown.
Methods and results
We took a simulated gastric/pancreatic digestion protocol to perform in vitro digestion of milk exosomes, explore intestinal epithelial uptake, and further elucidate microRNA responses to digestion at early‐, mid‐, late lactation by massive parallel sequencing. Both undigested and digested exosomes enter human intestinal crypt‐like cells (HIEC), with evidence of nuclear localization. We identified 288 mature microRNAs from all 24 exosome samples, and an additional 610 at low abundance. A large number of synapse development‐ and immune‐related microRNAs were identified. hsa‐miR‐22‐3p was the most abundant microRNA, and the top 15 microRNAs contributed ∼11% of the sequencing reads. Upon digestion, the overall microRNA abundance in human milk exosomes was stable.
Conclusion
Our results for the first time reveal the survivability and complexity of human milk exosome microRNAs upon simulated gastric/pancreatic digestion, and the dynamics during lactation stages. The results suggest a previously underexplored area of infant response to genetic material in human milk exosomes.
After simulated gastric/pancreatic digestion mimicking human infant gut environment, human milk exosomes are taken up by crypt‐like HIEC cells, with evidence of nuclear localization. Two hundred and eighty eight mature exosome microRNAs from 24 milk samples collected at different lactation stages, and an additional 610 at low abundance. A large number of synapse development‐ and immune‐related microRNAs were identified. Upon digestion, the overall microRNA abundance in human milk exosomes was stable.
Cow's milk is considered the best wholesome supplement for children since it is highly enriched with micro and macro nutrients. Although the protein fraction is composed of more than 25 proteins, ...only a few of them are capable of triggering allergic reactions in sensitive consumers. The balance in protein composition plays an important role in the sensitization capacity of cow's milk, and its modification can increase the immunological response in allergic patients. In particular, the heating treatments in the presence of a food matrix have demonstrated a decrease in the milk allergenicity and this has also proved to play a pivotal role in developing tolerance towards milk. In this paper we investigated the effect of thermal treatment like baking of cow's milk proteins that were employed as ingredients in the preparation of muffins. A proteomic workflow was applied to the analysis of the protein bands highlighted along the SDS gel followed by western blot analyses with sera of milk allergic children in order to have deeper information on the impact of the heating on the epitopes and consequent IgE recognition. Our results show that incorporating milk in muffins might promote the formation of complex milk-food components and induce a modulation of the immunoreactivity towards milk allergens compared to milk baked in the oven at 180 °C for ten minutes. The interactions between milk proteins and food components during heating proved to play a role in the potential reduction of allergenicity as assessed by in vitro tests. This would help, in perspective, in designing strategies for improving milk tolerance in young patients affected from severe milk allergies.
Purpose
Modern food technology allows designing products aiming to simulate and replace traditional food. In affluent societies there is a rising tendency to consume foods derived from plants ...including milk imitations or plant drinks based on cereals, nuts, legumes, oil seeds or other plant families. Herein we review production and composition of such drinks, summarize consumers’ motivations to change from milk to plant drinks and highlight nutritional and health implications of consuming plant drinks instead of milk, in particular if non-fortified and if consumed by infants, children, adolescents and the elderly.
Results
Whereas the macronutrient concentrations of some plant drinks (soy) may approach in some cases (protein) that of cow’s milk, the nutritional quality of most plant drinks, e.g., the biological value of protein and the presence and amount of vitamins and essential minerals with high bioavailability does not. If cow’s milk is exchanged for non-fortified and non-supplemented plant drinks consumers may risk deficiencies of calcium, zinc, iodine, vitamins B2, B12, D, A, and indispensable amino acids, particularly in infants and toddlers who traditionally consume significant portions of milk. The vegetable nature, appearance and taste of such plant drinks may be appealing to adult consumers and be chosen for adding variety to the menu. However, in young children fed exclusively such plant drinks severe metabolic disturbances may occur.
Conclusion
Parents, dietitians, physicians and consumers should be aware of such potential risks, if non-fortified plant drinks are consumed instead of milk.
Digestion of milk proteins in the premature infant stomach releases functional peptides; however, which peptides are present has not been reported. Premature infants are often fed a combination of ...human milk and bovine milk fortifiers, but the variety of functional peptides released from both human and bovine milk proteins remains uncharacterized. This study applied peptidomics to investigate the peptides released in gastric digestion of mother's milk proteins and supplemental bovine milk proteins in premature infants. Peptides were assessed for homology against a database of known functional peptides-Milk Bioactive Peptide Database. The peptidomic data were analyzed to interpret which proteases most likely released them from the parent protein. We identified 5,264 unique peptides from bovine and human milk proteins within human milk, fortifier or infant gastric samples. Plasmin was predicted to be the most active protease in milk, while pepsin or cathepsin D were predicted to be most active in the stomach. Alignment of the peptide distribution showed a different digestion pattern between human and bovine proteins. The number of peptides with high homology to known functional peptides (antimicrobial, angiotensin-converting enzyme-inhibitory, antioxidant, immunomodulatory, etc.) increased from milk to the premature infant stomach and was greater from bovine milk proteins than human milk proteins. The differential release of bioactive peptides from human and bovine milk proteins may impact overall health outcomes in premature infants.
Heating processes are applied to milk and dairy products to ensure their microbiological safety and shelf lives. However, how differences in “industrial” thermal treatments affect protein ...digestibility is still equivocal. In this study, raw milk was subjected to pasteurization, three kinds of ultra-high-temperature (UHT) treatment, and in-can sterilization and was investigated by in vitro and in vivo digestion and proteomic methods. In-can sterilized milk, followed by UHT milk samples, showed a rapid decrease in protein bands during the course of digestion. However, protein digestibility determined by a Kjeldahl procedure showed insignificant differences. Proteomic analysis revealed that lactulosyllysine, which reflects a decrease in protein digestibility, in α-lactalbumin, β-lactoglobulin, and caseins was higher in in-can sterilized milk, followed by UHT milk samples. Thus, industrial heating may improve the digestibility of milk proteins by denaturation, but the improvement is likely to be offset by heat-derived modifications involved in decreased protein digestibility.
Cow's milk allergy (CMA) and gastro-esophageal reflux disease (GERD) may manifest with similar symptoms in infants making the diagnosis challenging. While immediate reaction to cow's milk protein ...indicate CMA, regurgitation, vomiting, crying, fussiness, poor appetite, sleep disturbances have been reported in both CMA and GERD and in other conditions such as functional gastrointestinal disorders, eosinophilic esophagitis, anatomic abnormalities, metabolic and neurological diseases. Gastrointestinal manifestations of CMA are often non-IgE mediated and clinical response to cow's milk free diet is not a proof of immune system involvement. Neither for non-IgE CMA nor for GERD there is a specific symptom or diagnostic test. Oral food challenge, esophageal pH impedance and endoscopy are recommended investigations for a correct clinical classification but they are not always feasible in all infants. As a consequence of the diagnostic difficulty, both over- and under- diagnosis of CMA or GERD may occur. Quite frequently acid inhibitors are empirically started. The aim of this review is to critically update the current knowledge of both conditions during infancy. A practical stepwise approach is proposed to help health care providers to manage infants presenting with persistent regurgitation, vomiting, crying or distress and to solve the clinical dilemma between GERD or CMA.
Bovine milk contains extracellular vesicles (EVs), which act as mediators of intercellular communication by regulating the recipients’ cellular processes via their selectively incorporated bioactive ...molecules. Because some of these EV components are evolutionarily conserved, EVs present in commercial milk might have the potential to regulate cellular processes in human consumers.
Because commercial milk is subjected to industrial processing, we investigated its effect on the number and integrity of isolated milk EVs and their bioactive components. For this, we compared EVs isolated from raw bovine milk with EVs isolated from different types of commercial milk, including pasteurized milk, either homogenized or not, and ultra heat treated (UHT) milk.
EVs were separated from other milk components by differential centrifugation, followed by density gradient ultracentrifugation. EVs from different milk types were compared by single-particle high-resolution fluorescence-based flow cytometry to determine EV numbers, Cryo-electron microscopy to visualize EV integrity and morphology, western blot analysis to investigate EV-associated protein cargo, and RNA analysis to assess total small RNA concentration and milk-EV-specific microRNA expression.
In UHT milk, we could not detect intact EVs. Interestingly, although pasteurization (irrespective of homogenization) did not affect mean ± SD EV numbers (3.4 × 108 ± 1.2 × 108–2.8 × 108 ± 0.3 × 107 compared with 3.1 × 108 ± 1.2 × 108 in raw milk), it affected EV integrity and appearance, altered their protein signature, and resulted in a loss of milk-EV-associated RNAs (from 40.2 ± 3.4 ng/μL in raw milk to 17.7 ± 5.4–23.3 ± 10.0 mg/μL in processed milk, P < 0.05).
Commercial milk, that has been heated by either pasteurization or UHT, contains fewer or no intact EVs, respectively. Although most EVs seemed resistant to pasteurization based on particle numbers, their integrity was affected and their molecular composition was altered. Thus, the possible transfer of bioactive components via bovine milk EVs to human consumers is likely diminished or altered in heat-treated commercial milk.
Camel, cow and human milk proteins were prepared and analyzed by two different gel electrophoretic techniques. The immunological cross-reactivity between camel and cow milk proteins was tested using ...immunoblotting and enzyme-linked immunosorbent assay (ELISA) techniques. Camel milk proteins have unique electrophoretic patterns that are completely different from cow and human milk proteins. When specific antisera to camel milk proteins were applied in immunoblotting (Western blot) analysis, results showed the absence of immunological cross-reactivity between camel and cow milk proteins. Similar results were obtained when sera from some children allergic to cow milk were tested for the specificity of their immunoglobulin E (IgE) to camel milk proteins. The study concluded that the absence of immunological similarity between camel and cow milk proteins can be considered an important criterion from the nutritional and clinical points of view, since camel milk may be suggested as a new protein source for nutrition for children allergic to cow milk and can be used as such or in a modified form.
The diagnosis of cow's milk allergy (CMA) is particularly challenging in infants, especially with non-Immunoglobulin E (IgE)-mediated manifestations, and inaccurate diagnosis may lead to unnecessary ...dietary restrictions. The aim of this study was to assess the accuracy of the cow's milk-related symptom score (CoMiSS
) in response to a cow's milk-free diet (CMFD). We prospectively recruited 47 infants (median age three months) who had been placed on a CMFD due to persisting unexplained gastrointestinal symptoms. We compared data with 94 healthy controls (median age three months). The CoMiSS
score was completed at recruitment and while on the exclusion diet. In 19/47 (40%) cases a response to the diet occurred. At recruitment CoMiSS
was significantly higher in cases compared to controls (median score 8 vs. 3;
-value: <0.05), 9 cases had a score ≥12 and 8/9 normalized on CMFD. An oral milk challenge was performed in all 19 responders and six of these had a positive reaction to cow's milk (CM). In eight infants IgE allergy tests were positive. The receiver operation characteristic (ROC) curve identified a CoMISS
score of 9 to be the best cut-off value (84% sensitivity, 85% specificity, 80% positive (PPV) and 88% negative predictive value (NPV)) for the response to CMFD. We found CoMiSS
to be a useful tool to help identify infants with persisting gastrointestinal symptoms and suspected CMA that would benefit from CMFD.
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