Viral, nutritional, and bacterial safety of flash-heated and pretoria-pasteurized breast milk to prevent mother-to-child transmission of HIV in resource-poor countries: a pilot study.

Background: Heat-treated breast milk of HIV-positive mothers has potential to reduce vertical transmission. This study compared the impact of flash-heating (FH) and Pretoria pasteurization (PP) on HIV, nutrients, and antimicrobial properties in human milk.

Methods: Milk samples were spiked with 1 x 10 (8) copies/mL of clade C HIV-1 and treated with FH and PP.

Molecular regulation of milk trace mineral homeostasis.

The regulation of milk trace mineral homeostasis requires the temporal integration of three main processes, (A) mineral uptake into the secretory mammary epithelial cell (MEC); followed by (B) mineral secretion from MEC into the alveoli lumen of the mammary gland for sequestration in milk; and then (C) milk release in response to suckling. Trace mineral requirements of term infants are generally met by exclusive breast-feeding through about the first 6 months of life and although milk zinc (Zn), iron (Fe), and copper (Cu) concentrations are relatively refractory to maternal trace mineral status, they normally decline throughout lactation. Recently, Zn-, Fe- and Cu-specific transporters have been identified that regulate trace element uptake and efflux in various cell types; however, there is currently little information available regarding the processes through which the mammary gland regulates milk trace mineral transport.

A follow-up study of nutrient intake, nutritional status, and growth in infants with cow milk allergy fed either a soy formula or an extensively hydrolyzed whey formula.

Background: Infants with cow milk allergy (CMA) are reported to have reduced growth and special nutritional needs.

Objective: The aim of the present study was to compare nutrient intake, nutritional status, and growth in infants with CMA who were fed either a soy formula or an extensively hydrolyzed whey formula.

Design: The study group comprised 168 double-blind challenge-proven infants with CMA.

Maternal zinc deficiency reduces NMDA receptor expression in neonatal rat brain, which persists into early adulthood.

Prenatal and early postnatal zinc deficiency impairs learning and memory and these deficits persist into adulthood. A key modulator in this process may be the NMDA receptor; however, effects of zinc deficiency on the regulation of NMDA receptor activity are not well understood. Female Sprague-Dawley rats were fed diets containing 7 (zinc deficient, ZD), 10 (marginally zinc deficient, MZD) or 25 (control) mg Zn/g diet preconception through postnatal day (PN) 20, at which time pups were weaned onto their maternal or control diet.

Induction of cytochrome P450 1A by cow milk-based formula: a comparative study between human milk and formula.

During the treatment of neonatal apnea, formula-fed infants, compared to breastfed infants, show nearly three-fold increase in clearance of caffeine, a substrate of cytochrome P450 1A (CYP1A) and in part CYP3A4. However, human milk is known to contain higher concentrations of environmental pollutants than infant formula, which are potent CYP1A inducers. To gain insight into the mechanism underlying this apparent contradiction, we characterized CYP1A and CYP3A4 induction by human milk and cow milk-based infant formula.

A graded model of dietary zinc deficiency: effects on growth, insulin-like growth factor-I, and the glucose/insulin axis in weanling rats.

Objective: Severe zinc (Zn) deficiency inhibits growth, insulin storage and release. Mild or moderate Zn deficiency may also have profound physiological effects that are not outwardly evident. We examined the effects of graded levels of low Zn intake on growth, insulin-like growth factor-I (IGF-I) and glucose homeostasis in weanling rats.

Neurobehavioral evaluation of rhesus monkey infants fed cow's milk formula, soy formula, or soy formula with added manganese.

The possible neurobehavioral effects of excess manganese in soy formula were studied. Male rhesus monkeys (n=8/group) were fed a commercial cow's milk based formula (Control), a commercial soy protein based formula (Soy), or the soy formula with added manganese (Soy+Mn) from birth to 4 months of age. Soy formulas naturally have higher manganese (Mn) content than cow's milk formulas.

Effects of chronic copper exposure during early life in rhesus monkeys.

Background: Whether infants regulate copper absorption and the potential effects of excess copper in early life remain poorly defined.

Objective: The objective of the study was to assess copper retention, liver copper content, and liver function in infant rhesus monkeys fed infant formula containing 6.6 mg Cu/L.

Zinc deficiency is associated with increased brain zinc import and LIV-1 expression and decreased ZnT-1 expression in neonatal rats.

Zinc (Zn) deficiency has been associated with adverse behavioral outcomes in infants and children. However, Zn deficiency does not affect brain Zn concentration, suggesting that brain Zn homeostasis is tightly regulated. The recent identification of Zn-specific transport proteins allowed us to examine effects of low Zn intake on tissue Zn level, brain Zn uptake, and zinc transporter expression and localization in neonatal rat brain.

Detection of a single nucleotide polymorphism in the human alpha-lactalbumin gene: implications for human milk proteins.

Variability in the protein composition of breast milk has been observed in many women and is believed to be due to natural variation of the human population. Single nucleotide polymorphisms (SNPs) are present throughout the entire human genome, but the impact of this variation on human milk composition and biological activity and infant nutrition and health is unclear. The goals of this study were to characterize a variant of human alpha-lactalbumin observed in milk from a Filipino population by determining the location of the polymorphism in the amino acid and genomic sequences of alpha-lactalbumin.

Iron transporters in rat mammary gland: effects of different stages of lactation and maternal iron status.

Background: Mechanisms regulating iron transfer from maternal circulation into milk are yet unknown. Whether intestinal iron transporters, divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1), are present in the mammary gland and are involved in iron transfer into milk are unknown.

Objective: The objective was to examine DMT1 and FPN1 in rat mammary gland at different stages of lactation and to evaluate the effects of maternal iron status.

Zip3 plays a major role in zinc uptake into mammary epithelial cells and is regulated by prolactin.

During lactation, a substantial amount of Zn(2+) is transferred by the mammary gland from the maternal circulation into milk; thus secretory mammary epithelial cells must tightly regulate Zn(2+) transport to ensure optimal Zn(2+) transfer to the suckling neonate. To date, six Zn(2+) import proteins (Zip1-6) have been identified; however, Zip3 expression is restricted to tissues with unique requirements for Zn(2+), such as the mammary gland, which suggests that it may play a specialized role in this tissue. In the present study, we have used a unique mammary epithelial cell model (HC11) to characterize the role of Zip3 in mammary epithelial cell Zn(2+) transport.

Low vitamin a intake affects milk iron level and iron transporters in rat mammary gland and liver.

Marginal vitamin A deficiency is common and can result in a secondary iron (Fe) deficiency. A positive correlation between maternal Fe status and milk Fe was observed in lactating women supplemented with both vitamin A and Fe but not with Fe alone, suggesting effects of vitamin A on mammary gland Fe transport. We hypothesized that low vitamin A intake during lactation elicits differential effects on mammary gland and liver Fe transport and storage proteins, thus affecting milk Fe concentration but not maternal Fe status.

Effects of copper supplementation on copper absorption, tissue distribution, and copper transporter expression in an infant rat model.

Infants are exposed to variable copper (Cu) intake; Cu in breast milk is low, whereas infant formulas vary in Cu content as well as the water used for their preparation. Little is known about the regulation of Cu absorption during infancy. The objectives of this study were to determine effects of Cu supplementation on Cu absorption and tissue distribution and the expression of Cu transporters in an infant rat model.

Anaemia and iron deficiency during pregnancy in rural Bangladesh.

Objective: To study the prevalence of anaemia and its association with measures of iron deficiency (ID) among a group of pregnant women.

Design: Cross-sectional survey.

Setting: Pregnant women identified through house-to-house visits and participating in community-based antenatal care activities in a rural location of Mymensingh, Bangladesh.

Iron in ferritin or in salts (ferrous sulfate) is equally bioavailable in nonanemic women.

Background: Recent studies in humans suggest that ferritin iron in soybeans has high bioavailability. However, direct evidence for this is lacking because the soybeans were intrinsically labeled; thus, iron bound to other ligands, such as phytate, was also labeled.

Objective: The objectives of the study were to evaluate the absorption of iron from extrinsically labeled, purified ferritin (horse spleen) reconstituted with either high-phosphate iron mineral (plant-type) or low-phosphate iron mineral (animal-type) and to compare it with iron absorption from ferrous sulfate.

Human milk proteins: key components for the biological activity of human milk.

Human milk contains a wide array of proteins that provide biologic activities ranging from antimicrobial effects to immunostimulatory functions. Proteins like lactoferrin, secretory IgA, kappa-casein, lactoperoxidase, haptocorrin, lactadherin and peptides formed from human milk proteins during digestion can inhibit the growth of pathogenic bacteria and viruses and therefore protect against infection. At the same time, proteins like lactoferrin, bile-salt stimulated lipase, haptocorrin, kappa-casein, and folate-binding protein can facilitate the absorption of nutrients in the neonatal gut.

A multinational study of alpha-lactalbumin concentrations in human milk.

Alpha-lactalbumin, a 14-kD protein, plays a central biochemical role in the mammary gland as the regulatory subunit of lactose synthase, and also plays a nutritional role for the rapidly growing neonate as the protein in highest concentration in human milk. The current study was undertaken to better characterize alpha-lactalbumin concentrations in human milk from a variety of countries. Mature human milk (lactation duration > or =1 month) was collected from at least 50 women from nine different countries on five continents.

A community-based randomized controlled trial of iron and zinc supplementation in Indonesian infants: effects on growth and development.

Background: Deficiencies of iron and zinc are associated with delayed development, growth faltering, and increased infectious-disease morbidity during infancy and childhood. Combined iron and zinc supplementation may therefore be a logical preventive strategy.

Objective: The objective of the study was to compare the effects of combined iron and zinc supplementation in infancy with the effects of iron and zinc as single micronutrients on growth, psychomotor development, and incidence of infectious disease.

Cellular internalization of lactoferrin in intestinal epithelial cells.

We studied the cellular internalization of lactoferrin (Lf) in an intestinal epithelial cell line, Caco-2, to investigate the mechanism of biological actions of ingested Lf. RT-PCR and Western blotting analyses revealed that differentiated Caco-2 cells express LfR mRNA and its protein with a 34 kD molecular weight under reducing conditions. Biotin-labeled Lf showed specific binding to the cellular membrane of differentiated Caco-2 cells with a dissociation constant (Kd) of 0.

Baculovirus expression of mouse lactoferrin receptor and tissue distribution in the mouse.

Lactoferrin (Lf) has been shown to have a role in the immune system and in early development of the mouse embryo. A specific receptor for Lf has been suggested to mediate the functions of Lf. We have recently identified a Lf receptor (LfR) in human fetal small intestine.

Maternal zinc deficiency raises plasma prolactin levels in lactating rats.

There is an inverse relation between zinc (Zn) intake and plasma prolactin in men and nonpregnant women. Whether a relation exists in lactating women is unknown, despite the potential consequences of perturbations in prolactin regulation on lactation performance. We examined the effects of low Zn intake on prolactin concentration, the prolactin regulatory pathway in the pituitary gland, and lactation performance in lactating rats.

Dietary iron intake is positively associated with hemoglobin concentration during infancy but not during the second year of life.

Iron status during infancy and early childhood reflects highly dynamic processes, which are affected by both internal and external factors. The regulation of iron metabolism seems to be subjected to developmental changes during infancy, although the exact nature of these changes and their implications are not fully understood. We wanted to explore the association between dietary iron intake and indicators of iron status, and to assess temporal changes in these variables.

Functional and molecular responses of suckling rat pups and human intestinal Caco-2 cells to copper treatment.

Ctr1 and Atp7A are copper (Cu) transporters that may play a role in the regulation of intestinal Cu absorption; however, intestinal regulation of these transporters by Cu in vivo has not been well defined. In this study, we hypothesized that Cu supplementation would alter the expression of intestine Ctr1 and Atp7A in vivo and further documented effects of Cu exposure on Cu transport, Ctr1 and Atp7A levels and localization in enterocyte-like Caco-2 cells. Suckling rat pups were supplemented with Cu (0 and 25 microg Cu/day) for 10 days and small intestine Cu concentration, Ctr1, Atp7A and metallothionein (MT) gene expression were measured by Northern blot analysis.