Publications by authors named "Hirohisa Izumi"

The gut microbiome and fecal metabolites of breastfed infants changes during lactation, and are influenced by breast milk components. This study aimed to investigate dynamic associations of milk components with the infant gut microbiome and fecal metabolites throughout the lactation period in a mother-infant model. One month after delivery, breast milk and subsequent infant feces were collected in a pair for 5 months from a mother and an exclusively breastfed infant.

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Background: Plasma albumin (ALB) reflects protein nutritional status in rats, but it is not clear whether it is associated with dietary protein insufficiency in pregnant women and/or their risk of low birth weight delivery. This study aimed to investigate whether maternal serum ALB redox state reflects maternal protein nutritional status and/or is associated with infant birth weights.

Methods: The relationship between the serum reduced ALB ratio and infant birth weight was examined in an observational study of 229 Japanese pregnant women.

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Extracellular vesicles (EV) are important for delivering biologically active substances to facilitate cell-to-cell communication. Milk-derived EV are widely known because of their potential for immune enhancement. However, procedures for isolating milk-derived EV have not been fully established.

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Protein undernutrition contributes to the development of various diseases in broad generations. Urinary metabolites may serve as non-invasive biomarkers of protein undernutrition; however, this requires further investigation. We aimed to identify novel urinary metabolites as biomarker candidates responsive to protein undernutrition.

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Background: Plasma albumin (ALB) redox state reflects protein nutritional status, but how it differs from other protein nutrition biomarkers remains to be fully elucidated.

Objective: This study aimed to delineate the characteristics of plasma ALB redox state as a protein nutrition biomarker.

Methods: Adult male Wistar rats were maintained on an AIN-93 M [14% casein, control (CT)] diet or an AIN-93 M-based 5% casein [low protein (LP)] diet ad libitum for 4 wk.

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We recently reported that plasma albumin redox state, which correlates with albumin synthesis rate, could be associated with the quality of dietary protein. Aiming to elucidate the association between them, plasma albumin redox state was investigated in rats fed various kinds of AIN-93G-based low protein diets. Plasma albumin redox state was shifted to a more oxidized state in rats fed 3% casein (CN) diet than those fed 3% whey protein or 3% wheat gluten diet, while supplementing 3% CN diet with cystine reversed it to a more reduced state, indicating that cystine would complement the shortage of cysteine in CN, thereby increasing albumin synthesis rate.

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Background: Several types of oligosaccharides are used in infant formula to improve the gut microbiota of formula-fed infants. We previously reported that a combination of 3 oligosaccharides (lactulose, raffinose, and galacto-oligosaccharides; LRG) and Bifidobacterium breve effectively increased B. breve numbers, acetate, and the expression of several immune- and gut hormone-related mRNAs in neonatal mice gut.

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Physicochemical properties of casein (CN) materials manufactured using different processes are well studied; however, data on their bioaccessibility or bioactivity are limited. We compared the digestion patterns and glucagon-like peptide-1 (GLP-1)-releasing activities of micellar CN concentrate (MCC) and sodium caseinate (SCN). MCC and SCN mixed with whey protein isolate (SCN + WPI) were subjected to in vitro gastrointestinal digestion; the digestibility of MCC was higher than that of SCN + WPI, and both CN materials showed different patterns of peptides released after in vitro digestion.

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The redox state of plasma albumin shifts in response to dietary protein intake in growing rats, and the shift is more sensitive than that of plasma albumin level, a classical marker of protein nutritional status. While it has been suggested that plasma albumin redox state could be useful as a novel marker of protein nutritional status, the above animal model is highly sensitive to dietary protein intake and the observation may not be extrapolated widely to humans. This study aimed to investigate whether albumin redox state also reflects protein nutritional status in adult rats, which have a lower dietary protein requirement and are less responsive to protein intake.

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Background: Epicutaneous sensitization to food allergens can occur through defective skin barriers. However, the relationship between oral tolerance and epicutaneous sensitization remains to be elucidated. We aimed to determine whether prior oral exposure to whey proteins or their hydrolysates prevents epicutaneous sensitization and subsequent food-allergic reaction to the whey protein, β-lactoglobulin (β-LG), and investigated the underlying mechanisms.

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It is important to provide formula-fed infants with a bifidobacteria-enriched gut microbiota similar to those of breastfed infants to ensure intestinal health. Prebiotics, such as certain oligosaccharides, are a useful solution to this problem, but the combinational benefits of these oligosaccharides have not been evaluated. This study investigated the benefits of oligosaccharide combinations and screened for an optimal combination of oligosaccharides to promote healthy gut microbiota of formula-fed infants.

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Background: Bifidobacterium breve M-16V (M16V) is a probiotic bacterial strain with a long tradition of use in neonatal intensive care units in some countries. Previous study showed that the effects of M16V administration on gene expression were greater during the weaning period than in the neonatal period and were greater in the colon than in the small intestine and spleen, suggesting that M16V has anti-inflammatory effects. In this study, we evaluated the effects of inflammation during the weaning period and the effects of M16V on normal and inflammatory conditions.

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We reported previously that microRNA (miRNA) are present in whey fractions of human breast milk, bovine milk, and rat milk. Moreover, we also confirmed that so many mRNA species are present in rat milk whey. These RNA were resistant to acidic conditions and to RNase, but were degraded by detergent.

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Functional RNAs, such as microRNA (miRNA) and mRNA, are present in milk, but their roles are unknown. To clarify the roles of milk RNAs, further studies using experimental animals such as rats are needed. However, it is unclear whether rat milk also contains functional RNAs and what their time dependent expression profiles are.

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MicroRNAs (miRNAs) are small regulatory RNA molecules that modulate specific target mRNAs and play very important roles in physiological processes. They were recently detected in body fluids such as blood, urine, saliva, and milk. These body fluid miRNAs have been studied thoroughly as potential diagnostic biomarkers.

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Introduction: To examine the immune-modulatory effects of probiotics during early infancy, Bifidobacterium breve M-16V (B. breve) was administered to rat pups during the newborn or weaning period, and the expression of inflammatory genes was investigated using a cDNA microarray and real-time PCR.

Results: After B.

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Background: Necrotizing enterocolitis (NEC) is a devastating intestinal disease of premature infants. Although ω-3 fatty acids are known to have antiinflammatory effects, their effect against NEC remains unclear.

Methods: Mother rats fed a soybean-based, docosahexaenoic acid (DHA)- or eicosapentaenoic acid (EPA)-enriched diet from days 7 to 20 of gestation were examined.

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Background: Breast milk is a complex liquid that provides nutrition to the infant and facilitates the maturation of the infant's immune system. Recent studies indicated that microRNA (miRNA) exists in human body fluid. Because miRNAs are known to regulate various immune systems, we hypothesized that human breast milk contains miRNAs that may be important for the development of the infant's immune system.

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Background: Neonatal necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. The mortality rate associated with NEC is quite high and in most reports ranges from 20 to 30%. Despite extensive studies, the pathogenesis of NEC remains poorly understood.

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We investigated the effects of endogenous glucagon-like peptide-2 (GLP-2) on the development of intestinal mucosa in weanling rats. Three-week-old male weanling Sprague-Dawley rats were administered either anti-GLP-2 or normal rabbit serum every other day for 2 weeks. We then measured length, weight, and bromodeoxyuridine incorporation in the intestine on day 13 following the first injection.

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We investigated whether bovine milk constituents influenced glucagon-like peptide (GLP)-2 secretion and intestinal growth in suckling rats. Male Sprague-Dawley rats (14 d old) received i.g.

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To obtain large amounts of deglycosylated procarboxypeptidase Y (proCPY), in which all of the N-glycosylation sites were replaced by alanine residue by the point mutation method, an expression system was constructed using Pichia pastoris. The secreted enzyme was characterized by SDS-PAGE, native PAGE, MALDI-TOF mass spectrometry, and dynamic light scattering, and the results indicated heterogeneity. The recombinant proCPY contained 29 mol of glucose per mole of protein in average, according to the carbohydrate analysis by the phenol-sulfuric acid method.

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