Changes in Proteases, Antiproteases, and Bioactive Proteins From Mother's Breast Milk to the Premature Infant Stomach

Demers‐Mathieu, Véronique; Nielsen, S. B.; Underwood, Mark A.; Borghese, Robyn; Dallas, David C.

doi:10.1097/mpg.0000000000001719

Cited by 31 publications

(33 citation statements)

References 43 publications

(53 reference statements)

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“…Our previous study found that cathepsin D and plasmin from human milk were still active in the preterm stomach at two hours postprandial. Our recent research also demonstrated that pepsin/cathepsin D activities and proteolysis increased from human milk to the preterm infant stomach at two hours postprandial.…”

Section: Discussionmentioning

confidence: 94%

“…The results are expressed as units per millilitre, where one unit of protease activity is the amount of enzyme that generates 1 μ mol of L‐tyrosine per min. For protease activity in human milk, the assay buffer (initial at pH 1.3) was adjusted with 1 M sodium hydroxide to pH 6.4 to approximate average milk pH from this study and our previous article . For protease activity in the gastric samples, the assay buffer was adjusted to pH 4.5 with 1 M sodium hydroxide to approximately match the average gastric sample pH of this study.…”

Section: Methodsmentioning

confidence: 99%

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The preterm infant stomach actively degrades milk proteins with increasing breakdown across digestion time

Demers‐Mathieu

Underwood

et al. 2018

Acta Paediatrica

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Aim: This study investigated the effect of time post-ingestion on gastric digestion and gastric hormones after feeding preterm infants unfortified and fortified human milk. Methods: Human milk and infant gastric samples were collected from 14 preterm (23–32 wk birth gestational age) mother-infant pairs within 7–98 days postnatal age. Gastric samples were collected 1, 2 and 3 h after beginning of feeding. Samples were analyzed for pH, proteolysis, general protease activity and the concentrations of pepsin, gastrin and gastrin-releasing peptide. One-way ANOVA with repeated measures followed by Tukey’s multiple comparisons test was used. Results: Gastric pH was significantly decreased after each hour in the preterm infant stomach from 1 to 3 h postprandial. Proteolysis increased significantly from human milk to gastric contents at 1, 2 and 3 h postprandial (by 62, 131% and 181%, p < 0.05). General protease activity increased significantly by 58% from human milk to the gastric contents at 2 h postprandial. Gastrin-releasing peptide was present in human milk whereas gastrin was produced in the infant stomach. Conclusion: Though preterm infants may digest human milk proteins to a lesser extent than term infants, we demonstrated that the preterm infant stomach actively degrades milk proteins with increasing breakdown over digestion time.

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Section: Discussionmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

The preterm infant stomach actively degrades milk proteins with increasing breakdown across digestion time

Demers‐Mathieu

Underwood

et al. 2018

Acta Paediatrica

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“…No study has compared the survival of Igs in the stomach or intestine between preterm and term infants. Our recent studies demonstrated that preterm infants partially degrade IgA but not IgG and IgM in the stomach [ 21 , 22 ]. A few studies have measured the survival of milk Igs to infant stool [ 17 , 38 ].…”

Section: Discussionmentioning

confidence: 99%

“…The human milk feedings were delivered via the nasogastric tubes over 30 min. Two hours after the initiation of feeding, 2 mL of each preterm and term infant’s gastric contents were collected in a syringe back through the feeding tube via suction as previously described in our studies [ 21 ]. Gastric samples were aspirated at 2 h postprandial to obtain samples that represented a compromise between when adequate sample remained recoverable from the stomach and a maximum feasible length of gastric digestion time had passed based on gastric emptying times [ 31 ].…”

Section: Methodsmentioning

confidence: 99%

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Comparison of Human Milk Immunoglobulin Survival during Gastric Digestion between Preterm and Term Infants

et al. 2018

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Human milk provides immunoglobulins (Igs) that supplement the passive immune system of neonates; however, the extent of survival of these Igs during gastric digestion and whether this differs between preterm and term infants remains unknown. Human milk, and infant gastric samples at 2 h post-ingestion were collected from 15 preterm (23–32 week gestational age (GA)) mother-infant pairs and from 8 term (38–40 week of GA) mother-infant pairs within 7–98 days postnatal age. Samples were analyzed via ELISA for concentration of total IgA (secretory IgA (SIgA)/IgA), total secretory component (SC/SIgA/SIgM), total IgM (SIgM/IgM), and IgG as well as peptidomics. Total IgA concentration decreased by 60% from human milk to the preterm infant stomach and decreased by 48% in the term infant stomach. Total IgM and IgG concentrations decreased by 33% and 77%, respectively, from human milk to the term infant stomach but were stable in the preterm infant stomach. Release of peptides from all Ig isotypes in the term infant stomach was higher than in the preterm stomach. Overall, the stability of human milk Igs during gastric digestion is higher in preterm infant than in term infants, which could be beneficial for assisting the preterm infants’ immature immune system.

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The Enzymology of Human Milk

Chan

Beverly

Dallas

2021

Food Engineering Series

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Changes in Proteases, Antiproteases, and Bioactive Proteins From Mother's Breast Milk to the Premature Infant Stomach

Abstract: Most human milk proteases are active in milk but not at preterm infant gastric pH. Only cathepsin D and plasmin have potential to continue degrading milk proteins within the preterm infant stomach.

Cited by 31 publications

References 43 publications

The preterm infant stomach actively degrades milk proteins with increasing breakdown across digestion time

The preterm infant stomach actively degrades milk proteins with increasing breakdown across digestion time

Comparison of Human Milk Immunoglobulin Survival during Gastric Digestion between Preterm and Term Infants

The Enzymology of Human Milk

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