Epidermal growth factor in human and bovine milk

ERBB Receptors and Their Ligands in the Developing Mammary Glands of Different Species: Fifteen Characters in Search of an Author

The ERBB tyrosine kinase receptors and their ligands belong to a complex family that has diverse biological effects and expression profiles in the developing mammary glands, where its members play an essential role in translating hormone signals into local effects. While our understanding of these processes stems mostly from mouse models, there is the potential for differences in how this family functions in the mammary glands of other species, particularly in light of their unique histomorphological features. Herein we review the postnatal distribution and function of ERBB receptors and their ligands in the mammary glands of rodents and humans, as well as for livestock and companion animals. Our analysis highlights the diverse biology for this family and its members across species, the regulation of their expression, and how their roles and functions might be modulated by varying stromal composition and hormone interactions. Given that ERBB receptors and their ligands have the potential to influence processes ranging from normal mammary development to diseased states such as cancer and/or mastitis, both in human and veterinary medicine, a more complete understanding of their biological functions should help to direct future research and the identification of new therapeutic targets.

Milk Proteins-Their Biological Activities and Use in Cosmetics and Dermatology

Milk and colostrum have high biological potential, and due to their natural origin and non-toxicity, they have many uses in cosmetics and dermatology. Research is ongoing on their potential application in other fields of medicine, but there are still few results; most of the published ones are included in this review. These natural products are especially rich in proteins, such as casein, β-lactoglobulin, α-lactalbumin, lactoferrin, immunoglobulins, lactoperoxidase, lysozyme, and growth factors, and possess various antibacterial, antifungal, antiviral, anticancer, antioxidant, immunomodulatory properties, etc. This review describes the physico-chemical properties of milk and colostrum proteins and the natural functions they perform in the body and compares their composition between animal species (cows, goats, and sheep). The milk- and colostrum-based products can be used in dietary supplementation and for performing immunomodulatory functions; they can enhance the effects of certain drugs and can have a lethal effect on pathogenic microorganisms. Milk products are widely used in the treatment of dermatological diseases for promoting the healing of chronic wounds, hastening tissue regeneration, and the treatment of acne vulgaris or plaque psoriasis. They are also increasingly regarded as active ingredients that can improve the condition of the skin by reducing the number of acne lesions and blackheads, regulating sebum secretion, ameliorating inflammatory changes as well as bestowing a range of moisturizing, protective, toning, smoothing, anti-irritation, whitening, soothing, and antiaging effects.

Invited review: Growth-promoting effects of colostrum in calves based on interaction with intestinal cell surface receptors and receptor-like transporters

The postnatal development and maturation of the gastrointestinal (GI) tract of neonatal calves is crucial for their survival. Major morphological and functional changes in the calf's GI tract initiated by colostrum bioactive substances promote the establishment of intestinal digestion and absorption of food. It is generally accepted that colostrum intake provokes the maturation of organs and systems in young calves, illustrating the significance of the cow-to-calf connection at birth. These postnatal adaptive changes of the GI tissues in neonatal calves are especially induced by the action of bioactive substances such as insulin-like growth factors, hormones, or cholesterol carriers abundantly present in colostrum. These substances interact with specific cell-surface receptors or receptor-like transporters expressed in the GI wall of neonatal calves to elicit their biological effects. Therefore, the abundance and activity of cell surface receptors and receptor-like transporters binding colostral bioactive substances are a key aspect determining the effects of the cow-to-calf connection at birth. The present review compiles the information describing the effects of colostrum feeding on selected serum metabolic and endocrine traits in neonatal calves. In this context, the current paper discusses specifically the consequences of colostrum feeding on the GI expression and activity of cell-receptors and receptor-like transporters binding growth hormone, insulin-like growth factors, insulin, or cholesterol acceptors in neonatal calves.

Insulin-like growth factors (IGFs), IGF binding proteins, and other endocrine factors in milk: role in the newborn

The role of colostrum and milk in the neonate has been chiefly recognized as a comprehensive nutrient foodstuff. In addition, the provision of colostrum-the first milk-for early immune capacity has been well documented for several species. Colostrum is additionally a rich and concentrated source of various factors that demonstrate biological activity in vitro. Three hypotheses have been proposed for the phenotypic function of these secreted bioactive components: (1) only mammary disposal, (2) mammary cell regulation, and (3) neonatal function [gastrointestinal tract (GIT) or systemic]. Traditionally, it was assumed that the development of the GIT is preprogrammed and not influenced by events occurring in the intestinal lumen. However, a large volume of research has demonstrated that colostrum (or milk-borne) bioactive components can basically contribute to the regulation of GIT growth and differentiation, while their role in postnatal development at physiological concentrations has remained elusive. Much of our current understanding is derived from cell culture and laboratory animals, but experimentation with agriculturally important species is taking place. This chapter provides an overview of work conducted primarily in neonatal calves and secondarily in other species on the effects on neonates of selected peptide endocrine factors (hormones, growth factors, in part cytokines) in colostrum. The primary focus will be on insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) and other bioactive peptides, but new interest and concern about steroids (especially estrogens) in milk are considered as well.

Antitumor effects of Nafamostat mesilate on head and neck squamous cell carcinoma

OBJECTIVE

Nafamostat mesilate (FUT-175), a synthetic serine protease inhibitor, has antitumor activities toward adenocarcinoma, e.g., colon cancer. However, its antitumor effects on other types of cancer have been less extensively studied. We investigated the biological activities of Nafamostat mesilate on cell proliferation, cell-invasive potential and growth factor production in head and neck squamous cell carcinoma (HNSCC).

METHODS

Two human HNSCC cell lines established in our department, YCU-L891 and -H891, and a human vulvar squamous cell carcinoma cell line, A431, were examined for the effect of Nafamostat mesilate. The effects on cell growth were evaluated using the MTT assay. The effects on the relative expression levels of mRNA were measured by quantitative RT-PCR. Cytokine secretion was analyzed by enzyme-linked immunosorbent assay.

RESULTS

Nafamostat mesilate inhibited the proliferation of two HNSCC cell lines, YCU-L891 and YCU-H891, and A431. In these cell lines, Nafamostat mesilate down-regulated both matrix metalloproteinase (MMP)-2 and -9. In addition, it reduced the productions of vascular endothelial growth factor (VEGF) and transforming growth factor beta1 (TGF-beta1) by the tumor cells.

CONCLUSION

Our results suggest that Nafamostat mesilate has potential for use as a treatment against local growth, invasion and metastasis of squamous cell carcinoma.

Multi-modal approach to prophylaxis of necrotizing enterocolitis: clinical report and review of literature

For the first time a multimodal approach to NEC prophylaxis is reported, consisting of early trophic feeding with human breast milk, and enteral administration of an antibiotic, an antifungal agent, and probiotics. A retrospective analysis of local protocol of NEC prophylaxis is presented. Included were all VLBWI admitted to the NICU, including transfers within the first 28 days of life. These infants were divided into two groups, an "inborn group" (infants admitted within the first 24 h of life) and an "outborn group" (infants admitted after the onset of their second day of life). Prophylaxis of NEC according to protocol was started at the day of admission, and was continued until discharge. Between 1998 and 2004, 405 VLBWI were admitted, including all transfers within the first 28 days of life. A total of 334 (82%) infants were admitted within the first 24 h of life (inborn group), and 71 (18%) were admitted after 24 h of life (outborn group). Five infants developed clinical features of necrotizing enterocolitis. The inborn group showed a NEC incidence of 0.7% (two infants), whereas the outborn group showed a NEC incidence of 4.5% (three infants), respectively. This difference was significant (P=0.049, Fisher's exact test). A surgical treatment with bowel resection was performed in two infants (both from the outborn group). The present study used a combination of different strategies, all having shown to have some beneficial effect, but not having brought a clinical breakthrough in single administration studies. Combinated were the beneficial effects of human breast milk feeding, oral antiobiotics, oral antifungal agents, and the administration of probiotics. In a homogenous group of preterm infants, using this protocol of multimodal NEC prophylaxis, there was a very low incidence of NEC, when started within the first 24 h of life.

Necrotizing enterocolitis: preventative strategies

Necrotizing enterocolitis (NEC) remains a major cause of morbidity and mortality in premature infants. Although the pathogenesis of NEC is unclear, prevention strategies have been developed based on clinical observations and epidemiologic and experimental data. Most current strategies have centered on feeding practices (eg, institution of feeds, advancement of feeds, composition of feeds, and standardization of feeding practices). Emerging strategies include amino acid supplementation, the use of platelet-activating factor(PAF) antagonists or PAF-acetylhydrolase administration, polyunsaturated fatty acid administration, epidermal growth factor administration, and the use of pre- and probiotics.

Epidermal growth factor and necrotizing enterocolitis

As the number of extremely low-birth-weight infants increases,necrotizing enterocolitis remains a critical eminent problem. Supplementation of enteral feeds with biologically active substances normally present in breast milk, such as epidermal growth factor, seems to be a logical and safe way to reduce the incidence of intestinal inflammation and necrotizing enterocolitis. Continuing basic research and clinical studies are essential before epidermal growth factor can be introduced as an efficient therapeutic approach in the treatment of neonatal necrotizing enterocolitis.

Increased epidermal growth factor levels in human milk of mothers with extremely premature infants

Maternal milk is the major source of nutrients and growth-promoting substances in the first weeks of life for the majority of neonates. Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) are trophic peptides present in human milk with significant healing effects on injured gastrointestinal mucosa. Decreasing gestational age of neonates is associated with higher risk of developing gastrointestinal disorders, and human milk provides better protection against these diseases compared with formula. The aim of this study was to evaluate the concentrations of EGF and TGF-alpha in human milk collected from mothers with infants born: extremely preterm, preterm, and full term. Milk samples were collected at the end of first, second, and fourth week postpartum from each mother of infants born in one of the three gestational age groups: extremely preterm (23-27 wk, n = 16), preterm (32-36 wk, n = 16), and full term (38-42 wk, n = 15). Milk concentrations of EGF and TGF-alpha were quantified with a homologous RIA in the milk aqueous fraction. Concentrations of EGF in human milk from the extremely preterm group (23-27 wk) were significantly higher compared with values from the preterm and full-term groups throughout the first month of lactation. A similar pattern was observed with human milk TGF-alpha; however, milk TGF-alpha levels were lower than EGF. In conclusion, we have found higher concentrations of EGF and TGF-alpha in human milk of mothers with extremely preterm babies. These data may indicate the potential importance of milk-borne EGF and TGF-alpha for the development of extremely premature infants.

The clinical, morphologic, and molecular changes in the ileum associated with early postnatal dexamethasone administration: from the baby's bowel to the researcher's bench

Focal small bowel perforation (FSBP) is a life-threatening event that predominantly affects extremely low birth weight (ELBW) infants. Histopathology from surgical specimens of ileum with FSBP shows a healthy mucosa overlying a thinned muscularis with segmental degeneration. Clinical data strongly support an association between early postnatal administration of dexamethasone (EPD) and FSBP. Additional risk factors, including gestational age, administration of prophylactic indomethacin, and severity of illness, may be synergistic with EPD for the pathogenesis of perforations. Animal models of dexamethasone administration show morphologic changes in the ileum, similar to those seen in ELBW infants, including increased mucosal maturation and thinning of the muscularis. These tissue-specific differences may be mediated by a perturbation in growth factor expression or accumulation. In support of this hypothesis, dexamethasone has been associated with increased IGF-I immunolocalization in the mucosa and decreased immunolocalization in the muscularis. The known growth-promoting functions of IGF-I are consistent with the observed dexamethasone-associated changes within both the mucosa and the muscularis. Ongoing studies in this animal model are exploring the potential mechanisms by which dexamethasone might affect IGF-I availability.

Course of epidermal growth factor (EGF) and insulin-like growth factor I (IGF-I) in mammary secretions of the goat during end-pregnancy and early lactation

The epidermal growth factor (EGF) plays a crucial role in mammogenesis in many species. In ruminants, studies are limited, as EGF does not occur in peripheral plasma and specific analytical systems do not exist. Therefore a heterologous radioimmunoassay based on rhEGF was set up to monitor EGF in mammary gland secretions from goats during end-pregnancy and early lactation. IGF-I was measured with an established radioimmunoassay. Samples were collected from 13 goats for 25 days ante-partum and 25 days post-partum. Mammary gland secretions were obtained ante-partum by removing a small amount of the udder secretions (control half) or milking (stimulated half). Post-partum normal milk samples were collected. Blood samples were drawn by jugular venipuncture for the same period. EGF was found to occur in different molecular weight forms in the mammary glands. For routine measurements these proteins were extracted with acetone and not further separated. IGF-I and EGF concentrations in mammary secretions and similarly IGF-I in blood were high ante-partum and decreased slightly towards birth. IGF-I but not EGF is found in the peripheral plasma. Whereas IGF-I concentrations in blood were quite constant post-partum, IGF-I and EGF dropped in mammary secretions close to the detection limits. The decrease was more pronounced in the stimulated half than in the control half. The data support a synergistic role for EGF and IGF-I for mammogenesis. Both factors are further influenced by the milking stimulus and thus the functional state of the udder.

Human milk and infant formula can induce in vitro adipocyte differentiation in murine 3T3-L1 preadipocytes

The potential of infant diet to influence fat cell development has largely been examined in clinical studies with conflicting results. In this study, the direct effects of two standard infant formulas, Enfamil and Similac, as well as human milk were examined using a well characterized model of adipocyte differentiation, the 3T3-L1 murine preadipocyte cell line. After exposure to a hormonal regimen of insulin, dexamethasone, and 1-methyl-3-isobutylmethylxanthine, these cells undergo a mitotic expansion phase followed by terminal differentiation. On d 4 of hormonal exposure, greater than 95% of 3T3-L1 cells exhibit the morphologic and biochemical characteristics of mature adipocytes. In this study, cells were exposed to control medium, or control medium supplemented with either 10% Enfamil, 10% Similac, 10% human milk (skim or whole), or the standard hormonal regimen. Oil Red O-detectable lipid accumulation, immunocytochemical cell proliferation assays, and activated expression of adipocyte differentiation-specific mRNAs by Northern blot analysis were used to assess the effects of treatment on adipocyte differentiation. Results from each level of assessment revealed that both Enfamil and human milk were as effective as the standard hormonal regimen at stimulating adipocyte differentiation. In contrast, results from treatment with Similac or human skim milk were indistinguishable from control unstimulated cells. This study, demonstrating that Enfamil and human milk are capable of independently inducing in vitro adipocyte differentiation, suggests that diet during infancy could influence body fat development.

Biologically active factors in bovine milk and dairy byproducts: influence on cell culture

Substantial progress has been made in our knowledge of the biological properties of mammal milks. Many nutritional, biochemical, immunological, or other biological properties have been studied in mature or industrially processed bovine milk as well as in human milk and colostrum. This article is a critical review of selected publications covering (1) the use of bovine milk or dairy byproducts (processed acid and enzymatic whey fractions) as a serum substitute for cell cultures, (2) specific factors in bovine milk and industrially processed milk the affect cell proliferation, and (3) the known functional and biological roles of two whey proteins: beta-lactoglobulin and the PP3 component.

Cytokines in human milk: properties and potential effects upon the mammary gland and the neonate

Epidemiologic and immunologic studies of breastfed and nonbreastfed infants and investigations of certain biologic activities in human milk led to the identification of immunomodulating agents in human milk. Among them were the cytokines interleukin-1 beta (IL-1 beta); IL-6, IL-8, IL-10, granulocyte-colony stimulating factor, macrophage-colony stimulating factor (M-CSF), tumor necrosis factor-alpha, interferon-gamma, epithelial growth factor (EGF), transforming growth factor-alpha (TGF-alpha), and TGF-beta 2. Interferon-gamma may originate from T cells in milk; EGF, TGF-alpha, TGF-beta, M-CSF, IL-6, and IL-8 may be produced by mammary gland epithelium. Based upon their known functions, we hypothesize that cytokines influence the development and immunologic function of the mammary gland and the neonate. Those in vivo functions remain to be defined by future investigations.

The potential physiological significance of milk-borne hormonally active substances for the neonate

This article reviews the presence and potential physiological significance of hormones and hormonally active substances (including growth factors) in human milk. Human milk has been found to contain several nonpeptide hormones and many peptide hormones and growth factors. In contrast to human breast milk, infant formulae lack some hormonally active peptides. There is little data concerning the effects of these agents on human neonates. Studies in immature experimental animals showing effects of orogastically administered hormones are summarized. The problems of supplementation of infant formula are discussed. Since hormones are present in the milk as a "cocktail" of potentially agonistic and antagonistic substances, one question is whether supplementation with a single agent would disturb this balance.

Stability of epidermal growth factor in the gastrointestinal lumen of suckling and weaned pigs

The stability of epidermal growth factor (EGF) in the gastrointestinal humen of 3-day-old suckling and 45-day-old weaned pigs was examined by incubating iodine labeled recombinant human EGF (hEGF) in the gastrointestinal fluids at 37 degrees C and monitoring the generation of acid soluble radioactivity. Chromatographic analysis and receptor binding study were also undertaken. The results showed that hEGF was quite stable in the gastric fluids in both suckling and weaned pigs with less than 20% degradation after 20 min incubation. The degradation rate in the intestinal fluids varied with the region of the small intestine and the age of the animals. At the proximal and mid regions of the small intestine in suckling pigs the degradation rate of hEGF after 20 min incubation was 5 and 20% respectively, while the degradation rate at the distal region was up to 50%. In the small intestinal lumen in weaned pigs the degradation rate of hEGF was much greater than that in suckling pigs, and the degradation rates at the proximal, mid and distal regions were 33, 51 and 56% respectively. Addition of acid soluble or casein fractions of porcine colostrum markedly reduced the degradation of hEGF in the intestinal fluids. These results indicate that milk-borne EGF is stable in the gastric and proximal intestinal humen in suckling pigs, and may play a role in regulating postnatal development in the suckling young.

Effect of human colostrum on interleukin-2 production and natural killer cell activity

The effect of human colostrum on the production of interleukin-2 (IL-2) and on natural killer (NK) cell activity by peripheral blood mononuclear cells (PBMC) was investigated in 50 healthy women. At concentrations as low as 0.5%, human colostrum stimulated IL-2 production; at a higher concentration (10%), IL-2 secretion was inhibited. A time and dose dependent inhibitory effect of colostrum on NK cytotoxicity was also observed. This inhibition could be reversed by the addition of human recombinant IL-2 (hrIL-2). The stimulation of IL-2 production induced by human colostrum might compensate for its inhibitory effect on NK cell activity. These findings suggest an additional mechanism by which breast feeding may affect the neonatal immune system.

Extraction from cheese whey by cation-exchange chromatography of factors that stimulate the growth of mammalian cells

Bovine cheese whey was investigated as a source of growth-stimulating factors that might replace or supplement fetal bovine serum in cell culture. Although some cell growth activity was demonstrated in whey or whey ultrafiltrates, enrichment on the basis of molecular size was not useful because the most abundant whey proteins, beta-lactoglobulin and alpha-lactalbumin, have molecular masses that are similar to most known growth factors. Instead, cation-exchange chromatography was selected as an enrichment process because, in contrast to the major whey proteins, growth factors generally have basic isoelectric points. Adsorption to and elution from Sepharose Fast Flow-S resin yielded an extract containing only 1 to 2% of whey protein but substantial growth-promoting activities on Balb/c 3T3 cells, L6 myoblasts, and human skin fibroblasts. The growth activity could be separated from lactoferrin, one of the prominent basic proteins present, through a stepwise elution from the resin. The resultant fraction, which contained lactoperoxidase as the most abundant protein stimulated the growth of the three cell lines at protein concentrations that were 2- to 20-fold lower than observed with fetal bovine serum. Immunoglobulin G could be removed by affinity chromatography, or lactoperoxidase could be inactivated by heat, without significant losses to the growth-promoting capacity of the fraction. These results suggest that enrichment of growth factors by cation-exchange chromatography offers a practical method for the large-scale isolation of an extract from cheese whey that stimulates cell growth.