Bo Lonnerdal - US grants

lactation; breast feeding; nutrition related tag; human milk; infant human (0-1 year); developmental nutrition;

The human fetus is dependent on an adequate supply of zinc in order to achieve normal pre- and postnatal development. Because of its location, the placenta, and in particular, the placental trophoblast, must play a critically important role in the delivery of maternal zinc to the fetus. The major long-term objective of this proposal is to gain some understanding of the cellular mechanism involved in placental transport of maternal zinc to the fetus. In plasma, zinc is mostly found associated with albumin and alpha2M. Therefore, in the first specific aim we propose to use a combination of biochemical and morphological techniques to evaluate the roles of fluid-phase and adsorptive endocytosis in the uptake and processing of alpha2M and albumin. In the second specific aim we will study the uptake and processing of zinc in the form of complexes with alpha2M and albumin and to determine the factors and intracellular compartments involved in the dissociation and subsequent processing of protein-bound zinc. The third specific aim will investigate the kinetics and control of zinc release and attempt to discover the chemical form of the released metal. Together, these three specific aims should provide important new information on the cellular mechanisms involved in zinc uptake and metabolism by trophoblast. In specific aim four we will study the effects of zinc on the control of alpha2M receptor expression since changes in expression could have an effect on intracellular zinc levels and on zinc transport. In the last specific aim we will study the role of metallothionein in trophoblast zinc metabolism. Metallothionein has been implicated in the control of zinc homeostasis in a number of systems. We will examine metallothionein levels during differentiation in vitro as well as measuring rates of metallothionein synthesis and degradation.

nutrition; growth factor; clinical trials; Primates; Mammalia;

Significance Infant formulas contain considerable higher concentrations of manganese than human milk. Since very high body burdens of manganese may have toxic effects, it is important to study how well manganese is absorbed from various types of formula and how manganese status of infants is affected. Further, as manganese and iron compete for absorption, it is important to assess the effect of high manganese intake on hematology and iron status. Objectives To feed milk-based and soy-based infant formulas with different levels of manganese (35-200 ug/L) to infant monkeys from birth to 6 months of age and to study the effects on growth, manganese absorption and status, and the effects on hematology, iron absorption and status. Results Manganese and iron absorption was significantly lower from the formula with the highest level of manganese (soy formula) than from all other formulas at 6 weeks of age. At 3 months of age, however, there was no difference between the groups, suggesting that body burden of manganese does not affect manganese retention. Whole blood manganese reflected manganese intake and was highest in the group fed formula with the highest manganese level, while serum ferritin was lower in this group. Future Directions To evaluate the effect of increased levels of manganese in the body on various physiological functions. KEYWORDS manganese, manganese absorption, iron, iron status, infant nutrition

Significance Epidemiologically, breast-fed infants contract fewer infections and have infections of shorter duration. These differences may be attributed to differences in composition between breast milk and formula. Lactoferrin (a metal chelate glycoprotein found in human and primate milk) is known to possess antimicrobial activity as well as act against endotoxin induced inflammation. Additionally, lactoferrin may indirectly suppress pathogenic colonization by encouraging an environment more suitable for growth of more "host-friendly" bacteria. Thus the presence of lactoferrin in milk may account, in part, for the breast-fed infant's ability to withstand infection. Therefore, supplementation of infant formula with lactoferrin may help protect formula-fed infants from microbiologic infection. Objectives To feed infant monkeys formula supplemented with lactoferrin, inoculate them with a strain of E. coli and assess their ability to resist the infection and recolonize the intestine with Bifidobacteria and Lactobacilli. Results The intestinal flora of breast-fed monkeys differs from that of formula-fed monkeys in that formula-fed monkeys have a predominance of E. coli and breast-fed monkeys have a predominance of Lactobacilli. Additionally, lactoferrin seemed to prevent an increase in E. coli colonization while stimulating the colonization with Bifidobacteria or Lactobacilli. Future Directions To evaluate the effects of other prebiotics on various pathogens. KEY WORDS lactoferrin, E. coli, pathogens, prebiotic, infant nutrition FUNDING Private Sector

Significance Epidemiologically, breast-fed infants contract fewer infections and have infections of shorter duration. These differences may be due to differences in composition between breast milk and formula. Glycomacropeptide, (GMP, a highly negatively charged carbohydrate found in milk) may mimic the glycans that bacteria use for attachment in the small intestine and thus may inhibit attachment and colonization, thereby preventing infections. Alpha-lactalbumin, (ALA, a predominant milk protein) is believed to make a major contribution to the balanced plasma amino acid pattern of breast-fed infants and may aid in the absorption of calcium and zinc. The effects of GMP or ALA supplementation will be assessed by the capacity to respond to a microbial challenge as well as by tracing mineral and amino status. Objectives To study the effects of glycomacropeptide (GMP) and alpha-lactalbumin (ALA) on the colonization of pathogenic bacteria as well as anthropometry, hematology and indices of mineral nutriture in infant monkeys. Results Although no differences in length were observed, a significant differences in weight between animals fed GMP and breast-fed infants was found. GMP and ALA resulted in significant increases in serum zinc as 2, 3, 4 and 5 months of age. The absorption of zinc was higher in the animals receiving ALA or GMP as compared with breast-fed infants. Although there were no differences in thymus size, animals receiving ALA or breast milk responded differently to inoculation of E. coli as assessed by changes in differential white blood cell count. Future Directions To evaluate the effect of other milk protein fractions on various pathogens. KEY WORDS glycomacropeptide, alpha-lactalbumin, E. coli, pathogens, prebiotic, infant nutrition FUNDING Private Sector

nutrient intake activity; copper; health; Primates; infant animal; animal colony; clinical research; nutrition related tag;

nutrient intake activity; copper; health; Primates; infant animal; animal colony; clinical research; nutrition related tag;

proteins; metabolism; Primates; animal colony; clinical research;

cognition; ethology; manganese; Primates; animal colony; behavioral /social science research tag; clinical research;

DESCRIPTION (provided by applicant): Lactoferrin (Lf), an 80 kD glycoprotein that can bind two atoms of Fe(lll), is a major protein in human milk, and also present in exocrine secretions, e.g. pancreatic fluid and bile, and in neutrophils. Lf has been suggested to have several functions, including a role in intestinal Fe absorption, reproductive function, antimicrobial action, cellular proliferation and immune competence. However, although some support for such activities have been obtained, little is known about the mechanisms by which Lf exerts these functions. We previously showed the existence of Lf receptors (LfR) in human small intestine by kinetic binding studies. We have recently cloned and expressed human and mouse LfR, which are expressed in several tissues. Transfection of human intestinal cells showed increased uptake of iron and of Lf. In the proposed project we intend to determine the tertiary structure of LfR and the Lf-LfR complex by X-ray diffraction to better understand the organization of the LfR molecule and its interaction with Lf. We will also determine the specific site of the Lf molecule that binds to the LfR by using truncated versions (N-lobe, C-lobe) expressed as chimeras with transferrin in baculovirus. Peptides binding to the LfR will be generated by combinatorial chemistry. Oligonucleotide probes will be used for in situ hybridization and an LfR antibody will be used for immunostaining of human and mouse tissues, with particular emphasis on the small intestine and mouse embryonic development. Pathways of Lf internalization will be studied by inhibitors specifically inhibiting coated pits and caveolae-mediated pathways, respectively. Cellular responses to Lf mediated by the LfR will be studied by microarrays for signal transduction pathways. The effect of Fe, lipopolysaccharide (LPS) and nitric oxide on LfR expression will be studied by using several cell lines. We will also explore the biological significance of the LfR by using a conditional knockout mouse. We will clone the mouse LfR gene and construct a targeting vector in which the first exon is flanked by two Iox P sites. We will then use inducible cre transgenic mice to produce LfR knockouts in various tissues, such as small intestine and mammary gland, as well as at various stages of development. Basic properties of the knockouts will be compared with those of the wild type. Possible observations in the knockouts will be impaired reproduction and immune competence, decreased levels of Lf in milk, developmental abnormalities, lower Fe status of pups and diminished protective effect of Lf against LPS-caused mortality. Overall, our understanding of the physiological significance of Lf and its receptor will be increased.

0-11 years old; 0-6 weeks old; Adolescent; Adolescent Youth; Affect; Allergy; Allergy, Food; CRISP; Child; Child Youth; Children (0-21); Chronic Disease; Chronic Illness; Computer Retrieval of Information on Scientific Projects Database; Development; Drops; Food Hypersensitivity; Funding; Grant; Health; Human; Human, Child; Human, General; Hypersensitivity; Immune system; Infant; Infant, Newborn; Institution; Investigators; Man (Taxonomy); Man, Modern; Methods; Microbe; NIH; Nasal; National Institutes of Health; National Institutes of Health (U.S.); Newborn Infant; Newborns; Nose; Nose, Nasal Passages; Preventive; Research; Research Personnel; Research Resources; Researchers; Resources; Respiratory System, Nose, Nasal Passages; Societies; Source; T-Cells; T-Lymphocyte; Thymus-Dependent Lymphocytes; United States National Institutes of Health; body system, allergic/immunologic; children; chronic disease/disorder; chronic disorder; infancy; infantile; juvenile; juvenile human; newborn human (0-6 weeks); organ system, allergic/immunologic; thymus derived lymphocyte; youngster

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The goal of the project is to use metabolomics (urine and plasma) to evaluate nutritional status and metabolism in infants.